Primary Storage Form Research Articles

Can sprouting reduce phytate and improve the nutritional composition and nutrient bioaccessibility in cereals and legumes?

Sprouting is a traditional processing method which has been used for centuries to improve the nutritional value of cereals and legumes. There has been growing interest in sprouted products in recent years due to a high demand for more natural and healthy foods. Phytate is the primary storage form of phosphorus in plants. It is long recognised to affect human health as it forms insoluble complexes with minerals such as iron and zinc in cereals and legumes, thereby preventing their absorption in the body. Sprouting activates the enzyme phytase, which degrades phytate, thereby improving mineral bioaccessibility and bioavailability. The extent of phytate reduction varies depending on the sprouting conditions, cereal/legume species, cultivar and native phytase activity. Sprouting has been associated with increased iron, zinc and calcium bioaccessibility in many studies, but this appears to differ in cereals and legumes, which possibly is due to the presence of other 'antinutrients'. Protein digestibility also appears to be positively correlated with phytate reduction albeit less than for minerals. It is not possible to accurately predict the influence of sprouting on nutrient bioavailability because so few studies have been conducted. Further research is required to determine whether the commercial production of sprouted cereals and legumes can increase the nutritional value and health benefits of commercial end products.

Disrupting AMPK-Glycogen Binding in Mice Increases Carbohydrate Utilization and Reduces Exercise Capacity.

The AMP-activated protein kinase (AMPK) is a central regulator of cellular energy balance and metabolism and binds glycogen, the primary storage form of glucose in liver and skeletal muscle. The effects of disrupting whole-body AMPK-glycogen interactions on exercise capacity and substrate utilization during exercise in vivo remain unknown. We used male whole-body AMPK double knock-in (DKI) mice with chronic disruption of AMPK-glycogen binding to determine the effects of DKI mutation on exercise capacity, patterns of whole-body substrate utilization, and tissue metabolism during exercise. Maximal treadmill running speed and whole-body energy utilization during submaximal running were determined in wild type (WT) and DKI mice. Liver and skeletal muscle glycogen and skeletal muscle AMPK α and β2 subunit content and signaling were assessed in rested and maximally exercised WT and DKI mice. Despite a reduced maximal running speed and exercise time, DKI mice utilized similar absolute amounts of liver and skeletal muscle glycogen compared to WT. DKI skeletal muscle displayed reduced AMPK α and β2 content versus WT, but intact relative AMPK phosphorylation and downstream signaling at rest and following exercise. During submaximal running, DKI mice displayed an increased respiratory exchange ratio, indicative of greater reliance on carbohydrate-based fuels. In summary, whole-body disruption of AMPK-glycogen interactions reduces maximal running capacity and skeletal muscle AMPK α and β2 content and is associated with increased skeletal muscle glycogen utilization. These findings highlight potential unappreciated roles for AMPK in regulating tissue glycogen dynamics and expand AMPK’s known roles in exercise and metabolism.

Genome-Wide Identification of CYP72A Gene Family and Expression Patterns Related to Jasmonic Acid Treatment and Steroidal Saponin Accumulation in Dioscorea zingiberensis.

Dioscorea zingiberensis is a medicinal herb containing a large amount of steroidal saponins, which are the major bioactive compounds and the primary storage form of diosgenin. The CYP72A gene family, belonging to cytochromes P450, exerts indispensable effects on the biosynthesis of numerous bioactive compounds. In this work, a total of 25 CYP72A genes were identified in D. zingiberensis and categorized into two groups according to the homology of protein sequences. The characteristics of their phylogenetic relationship, intron–exon organization, conserved motifs and cis-regulatory elements were performed by bioinformatics methods. The transcriptome data demonstrated that expression patterns of DzCYP72As varied by tissues. Moreover, qRT-PCR results displayed diverse expression profiles of DzCYP72As under different concentrations of jasmonic acid (JA). Likewise, eight metabolites in the biosynthesis pathway of steroidal saponins (four phytosterols, diosgenin, parvifloside, protodeltonin and dioscin) exhibited different contents under different concentrations of JA, and the content of total steroidal saponin was largest at the dose of 100 μmol/L of JA. The redundant analysis showed that 12 DzCYP72As had a strong correlation with specialized metabolites. Those genes were negatively correlated with stigmasterol and cholesterol but positively correlated with six other specialized metabolites. Among all DzCYP72As evaluated, DzCYP72A6, DzCYP72A16 and DzCYP72A17 contributed the most to the variation of specialized metabolites in the biosynthesis pathway of steroidal saponins. This study provides valuable information for further research on the biological functions related to steroidal saponin biosynthesis.

Auxin Treatment Enhances Anthocyanin Production in the Non-Climacteric Sweet Cherry (Prunus avium L.).

Abscisic acid (ABA) is a key signaling molecule promoting ripening of non-climacteric fruits such as sweet cherry (Prunus avium L.). To shed light on the role of other hormones on fruit development, ripening and anthocyanin production, the synthetic auxin 1-naphthaleneacetic acid (NAA) was applied to sweet cherry trees during the straw-color stage of fruit development. NAA-treated fruits exhibited higher concentrations of 1-aminocyclopropane-1-carboxylic acid (ACC) and ABA-glucose ester (ABA-GE), which are a precursor of ethylene and a primary storage form of ABA, respectively. Consistent with these observations, transcript levels of genes encoding ACC synthase and ACC oxidase, both involved in ethylene biosynthesis, were increased after 6 days of NAA treatment, and both ABA concentration and expression of the regulator gene of ABA biosynthesis (NCED1 encoding 9-cis-epoxycarotenoid dioxygenase) were highest during early fruit ripening. In addition, transcript levels of key anthocyanin regulatory, biosynthetic and transport genes were significantly upregulated upon fruit exposure to NAA. This was accompanied by an increased anthocyanin concentration and fruit weight whilst fruit firmness and cracking index decreased. Altogether our data suggest that NAA treatment alters ethylene production, which in turn induces ripening in sweet cherry and enhanced anthocyanin production, possibly through ABA metabolism. The results from our study highlight the potential to use a single NAA treatment for manipulation of cherry ripening.

Plasma Lipolysis and Changes in Plasma and Cerebrospinal Fluid Signaling Lipids Reveal Abnormal Lipid Metabolism in Chronic Migraine.

BackgroundLipids are a primary storage form of energy and the source of inflammatory and pain signaling molecules, yet knowledge of their importance in chronic migraine (CM) pathology is incomplete. We aim to determine if plasma and cerebrospinal fluid (CSF) lipid metabolism are associated with CM pathology.MethodsWe obtained plasma and CSF from healthy controls (CT, n = 10) or CM subjects (n = 15) diagnosed using the International Headache Society criteria. We measured unesterified fatty acid (UFA) and esterified fatty acids (EFAs) using gas chromatography-mass spectrometry. Glycerophospholipids (GP) and sphingolipid (SP) levels were determined using LC-MS/MS, and phospholipase A2 (PLA2) activity was determined using fluorescent substrates.ResultsUnesterified fatty acid levels were significantly higher in CM plasma but not in CSF. Unesterified levels of five saturated fatty acids (SAFAs), eight monounsaturated fatty acids (MUFAs), five ω-3 polyunsaturated fatty acids (PUFAs), and five ω-6 PUFAs are higher in CM plasma. Esterified levels of three SAFAs, eight MUFAs, five ω-3 PUFAs, and three ω-6 PUFAs, are higher in CM plasma. The ratios C20:4n-6/homo-γ-C20:3n-6 representative of delta-5-desaturases (D5D) and the elongase ratio are lower in esterified and unesterified CM plasma, respectively. In the CSF, the esterified D5D index is lower in CM. While PLA2 activity was similar, the plasma UFA to EFA ratio is higher in CM. Of all plasma GP/SPs detected, only ceramide levels are lower (p = 0.0003) in CM (0.26 ± 0.07%) compared to CT (0.48 ± 0.06%). The GP/SP proportion of platelet-activating factor (PAF) is significantly lower in CM CSF.ConclusionsPlasma and CSF lipid changes are consistent with abnormal lipid metabolism in CM. Since plasma UFAs correspond to diet or adipose tissue levels, higher plasma fatty acids and UFA/EFA ratios suggest enhanced adipose lipolysis in CM. Differences in plasma and CSF desaturases and elongases suggest altered lipid metabolism in CM. A lower plasma ceramide level suggests reduced de novo synthesis or reduced sphingomyelin hydrolysis. Changes in CSF PAF suggest differences in brain lipid signaling pathways in CM. Together, this pilot study shows lipid metabolic abnormality in CM corresponding to altered energy homeostasis. We propose that controlling plasma lipolysis, desaturases, elongases, and lipid signaling pathways may relieve CM symptoms.

A Multicarbohydrase and Phytase Complex Is Able to Compensate a Nutrient-Deficiency in Growing-Finishing Pigs.

Simple SummaryPhytate is the primary storage form of phosphorus in grain-based feedstuffs, which can reduce the utilization of the phosphorus, calcium, and other minerals. Additionally, non-starch polysaccha-rides can increase digesta viscosity and thus decrease the nutrient digestion and utilization. The current study has evaluated the effects of a next-generation multicarbohydrase and phytase com-plex on the growth performance, apparent total tract digestibility of nutrients, carcass traits, and meat quality in growing-finishing pigs fed a corn-wheat-soybean meal-based diet. The results showed that dietary supplementation of the multicarbohydrase and phytase complex improved the growth performance and nutrient digestibility but had little effect on carcass traits and meat quality in growing-finishing pigs fed a corn-soybean meal-wheat-based diet. These findings indi-cate that the multicarbohydrase and phytase complex could be used as a promising enzymes product to mitigate the negative effects of phytate and non-starch polysaccharides.The objective of this study was to evaluate the efficacy of supplementing a corn-wheat-soybean meal-based diet with a multicarbohydrase and phytase complex (MCPC) on growth performance, apparent total tract digestibility (ATTD) of nutrients, carcass traits, and meat quality in growing-finishing pigs. A total of 300 pigs (Duroc × Large White × Landrace; body weight = 25.3 ± 0.7 kg) were randomly allotted to three groups with 10 replicates of 10 pigs each. Pigs from three groups were fed positive control (PC) or negative control (NC), without or with MCPC diets, respectively. The MCPC supplied at least 1800, 1244, 6600, and 1000 units of xylanase, β-glucanase, α-arabinofuranosidase, and phytase per kilogram of diet, respectively. The NC diet was the PC diet but reduced in net energy (NE), digestible amino acids (dig. AA), digestible P (dig. P), and Ca by 74 kcal/kg, 7.0%, 0.134, and 0.119 percentage points, respectively. The diets were fed in 4 growth phases based on body weight (BW): phase 1: 25–50 kg, phase 2: 50–75 kg, phase 3: 75–100 kg, and phase 4: 100–135 kg. Compared to the PC, the NC diet decreased (p < 0.05) body weight gain, feed intake, and(or) feed to gain ratio during the growing/finishing phases 1, 2, 3, and 4. It also reduced (p < 0.05) the ATTD of crude protein, crude fat, P, and Ca of pigs. MCPC supplementation improved (p < 0.05) the body weight gain, feed intake, and(or) feed to gain ratio in phases 2, 3, and 4 and the ATTD of crude protein, crude fat, ash, P, and Ca for the NC diet. Additionally, dietary treatment had no effects on carcass traits and meat quality with the exception that the loin eye area in the NC plus MCPC diet was higher (p < 0.05) than the NC diet. In conclusion, the addition of MCPC to a corn-soybean meal-wheat-based diet reduced in energy and nutrients improved the growth performance and nutrient digestibility but had little effect on carcass traits and meat quality in growing-finishing pigs.

Vitamin D and Calcium Supplements: Helpful, Harmful, or Neutral for Cardiovascular Risk?

Vitamin D has traditionally been known as the "bone vitamin". However, a large body of observational data has also linked low concentrations of serum 25-hydroxyvitamin D (25[OH]D), the primary storage form of vitamin D, to an increased risk of incident cardiovascular disease (CVD) and mortality, garnering public excitement about the purported nonskeletal benefits of vitamin D. Despite this, more recent meta-analyses and randomized clinical trials have failed to find a beneficial effect of vitamin D supplements on CVD and cancer outcomes. These findings, along with the lack of consensus on optimal serum 25(OH)D concentrations, have dampened some of the initial enthusiasm for vitamin D supplements. Residual confounding or reverse causation may explain some of the discrepancy between the observational and trial results. At this time, vitamin D supplements should not be prescribed for the primary purpose of CVD prevention. Adding to this complexity is the fact that many adults take vitamin D and calcium supplements together for bone health, and there is some concern (albeit inconclusive) related to calcium use and increased CVD risk. In this light, it may be best to achieve the recommended daily allowances of calcium intake through food and reserve calcium supplementation only for those at risk for calcium intake deficiency, with the smallest dosage needed after dietary modifications have been exhausted. In this review, we discuss vitamin D and calcium supplementation and how they may affect cardiovascular health.

The regulation and consequences of lipid droplet catabolism

Lipid droplets are recognized to be the primary storage form of energy in most cell types. While this important function is critical to supply cells or organisms with energy during times of nutrient deprivation, their role beyond energy storage has not been sufficiently explored. Our laboratory has focused on elucidating the mechanisms through which lipid droplets communicate within cells to coordinate energy storage with cell signaling and metabolism. This presentation will focus on the regulation of lipid droplet catabolism through cytosolic lipases and autophagic pathways. We will present data showing the role of perilipin 5, lipid droplet protein highly expressed in fasting liver, in mediating lipid droplet degradation. We will also explore the role of perilipin 5 as a key node that links lipolysis to downstream signaling networks that govern mitochondrial biogenesis, dynamics and function. In summary, this presentation will highlight novel roles for lipid droplets and resident lipid droplet proteins in cellular and organismal biology and their importance in human health.This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Macronutrients and the Adipose-Liver Axis in Obesity and FattyLiver.

Macronutrient metabolism is a highly orchestrated process, with adipose tissue and liver each playing central roles in nutrient uptake, processing, transport, and storage. These 2 tissues form an important metabolic circuit, particularly as it relates to lipids as the primary storage form of excess energy. The function of the circuit is influenced by many factors, including the quantity and type of nutrients consumed and their impact on the overall health of the tissues. In this review we begin with a brief summary of the homeostatic disposition of lipids between adipose tissue and liver and how these processes can become dysregulated in obesity. We then explore how specific dietary nutrients and nutrient combinations can exert unique influences on the liver–adipose tissue axis.

Inositol Hexakis Phosphate is the Seasonal Phosphorus Reservoir in the Deciduous Woody Plant Populus alba L.

Seasonal recycling of nutrients is an important strategy for deciduous perennials. Deciduous perennials maintain and expand their nutrient pools by the autumn nutrient remobilization and the subsequent winter storage throughout their long life. Phosphorus (P), one of the most important elements in living organisms, is remobilized from senescing leaves during autumn in deciduous trees. However, it remains unknown how phosphate is stored over winter. Here we show that in poplar trees (Populus alba L.), organic phosphates are accumulated in twigs from late summer to winter, and that IP6 (myo-inositol-1,2,3,4,5,6-hexakis phosphate: phytic acid) is the primary storage form. IP6 was found in high concentrations in twigs during winter and quickly decreased in early spring. In parenchyma cells of winter twigs, P was associated with electron-dense structures, similar to globoids found in seeds of higher plants. Various other deciduous trees were also found to accumulate IP6 in twigs during winter. We conclude that IP6 is the primary storage form of P in poplar trees during winter, and that it may be a common strategy for seasonal P storage in deciduous woody plants.

13C MRS Studies of the Control of Hepatic Glycogen Metabolism at High Magnetic Fields

Introduction: Glycogen is the primary intracellular storage form of carbohydrates. In contrast to most tissues where stored glycogen can only supply the local tissue with energy, hepatic glycogen is mobilized and released into the blood to maintain appropriate circulating glucose levels, and is delivered to other tissues as glucose in response to energetic demands. Insulin and glucagon, two current targets of high interest in the pharmaceutical industry, are well known glucose-regulating hormones whose primary effect in liver is to modulate glycogen synthesis and breakdown. The purpose of these studies was to develop methods to measure glycogen metabolism in real time non-invasively both in isolated mouse livers, and in non-human primates (NHPs) using 13C MRS. Methods: Livers were harvested from C57/Bl6 mice and perfused with [1-13C] Glucose. To demonstrate the ability to measure acute changes in glycogen metabolism ex-vivo, fructose, glucagon, and insulin were administered to the liver ex-vivo. The C1 resonance of glycogen was measured in real time with 13C MRS using an 11.7T (500 MHz) NMR spectrometer. To demonstrate the translatability of this approach, NHPs (male rhesus monkeys) were studied in a 7 T Philips MRI using a partial volume 1H/13C imaging coil. NPHs were subjected to a variable IV infusion of [1-13C] glucose (to maintain blood glucose at 3-4x basal), along with a constant 1 mg/kg/min infusion of fructose. The C1 resonance of glycogen was again measured in real time with 13C MRS. To demonstrate the ability to measure changes in glycogen metabolism in vivo, animals received a glucagon infusion (1 μg/kg bolus followed by 40 ng/kg/min constant infusion) half way through the study on the second study session. Results: In both perfused mouse livers and in NHPs, hepatic 13C-glycogen synthesis (i.e. monotonic increases in the 13C-glycogen NMR signal) was readily detected. In both paradigms, addition of glucagon resulted in cessation of glycogen synthesis and induction of glycogen breakdown. In the perfused liver, inclusion of insulin was able to dose-dependently block the effect of glucagon. Conclusion: Hepatic glycogen synthesis, as well as acute hormonally-induced changes thereof, can be measured using 13C MRS at high magnetic fields both ex-vivo

Progresses of the Past Decade on Factors Contributing to Skeletal Muscle Glycogen Synthase Regulation

Glycogen is the primary storage form of glucose, which is metabolized actively in the liver and skeletal muscle of mammals. The skeletal muscle glycogen is used intracellularly to provide starting substrate for glycolysis, whereas liver glycogen is used mainly for the maintenance of blood glucose homeostasis. The conversion of glucose to glycogen is an ordered process, in which the enzyme glycogen synthase plays an essential role. The key events in the synthesis of glycogen have been elucidated in both the liver and muscle. The process of understanding the regulatory mechanism of glycogen synthase activity has led to the discoveries of many important players in cellular metabolism. Research in identifying factors modulating muscle glycogen synthesis has been of popular interest within the past decade. The goal of this review is to summarize potential factors affecting skeletal muscle glycogen synthase expression level and activity in literatures published for the past decade.

Acetate supplementation as a means of inducing glioblastoma stem-like cell growth arrest.

Glioblastoma (GBM), the most common primary adult malignant brain tumor, is associated with a poor prognosis due, in part, to tumor recurrence mediated by chemotherapy and radiation resistant glioma stem-like cells (GSCs). The metabolic and epigenetic state of GSCs differs from their non-GSC counterparts, with GSCs exhibiting greater glycolytic metabolism and global hypoacetylation. However, little attention has been focused on the potential use of acetate supplementation as a therapeutic approach. N-acetyl-l-aspartate (NAA), the primary storage form of brain acetate, and aspartoacylase (ASPA), the enzyme responsible for NAA catalysis, are significantly reduced in GBM tumors. We recently demonstrated that NAA supplementation is not an appropriate therapeutic approach since it increases GSC proliferation and pursued an alternative acetate source. The FDA approved food additive Triacetin (glyceryl triacetate, GTA) has been safely used for acetate supplementation therapy in Canavan disease, a leukodystrophy due to ASPA mutation. This study characterized the effects of GTA on the proliferation and differentiation of six primary GBM-derived GSCs relative to established U87 and U251 GBM cell lines, normal human cerebral cortical astrocytes, and murine neural stem cells. GTA reduced proliferation of GSCs greater than established GBM lines. Moreover, GTA reduced growth of the more aggressive mesenchymal GSCs greater than proneural GSCs. Although sodium acetate induced a dose-dependent reduction of GSC growth, it also reduced cell viability. GTA-mediated growth inhibition was not associated with differentiation, but increased protein acetylation. These data suggest that GTA-mediated acetate supplementation is a novel therapeutic strategy to inhibit GSC growth.

Identification and characterization of a type-2 diacylglycerol acyltransferase (DGAT2) from Rhodosporidium diobovatum

Triacylglycerols (TAGs), synthesized in the microsomal membranes of eukaryotes, serve as a primary storage form of carbon and energy in microorganisms. For this reason, TAGs produced by organisms have great potential to become biofuels and facilitate researchers to look for alternative renewable sources of energy. The present study describes the identification and functional characterization of a type-2 diacylglycerol acyltransferase from Rhodosporidium diobovatum, designated as RdDGAT, which catalyzed the final step of TAG synthesis. A full-length cDNA clone for RdDGAT was obtained, and its biological activity was proven by being expressed in a Saccharomyces cerevisiae quadruple mutant that was defective in TAG synthesis. Enzymatic assays were performed and finally the existence of TAGs in the transformed Saccharomyces cerevisiae quadruple mutant was determined using the method of thin-layer chromatography. Substrate preference experiments revealed that RdDGAT preferred unsaturated fatty acids over saturated ones. Through further analysis, we assume that the evolution and expression characteristics of the RdDGAT gene perhaps is the result of adaption to its oligotrophic and cold living environment.

Acetate Supplementation Induces Growth Arrest of NG2/PDGFRα-Positive Oligodendroglioma-Derived Tumor-Initiating Cells

Cancer is associated with globally hypoacetylated chromatin and considerable attention has recently been focused on epigenetic therapies. N-acetyl-L-aspartate (NAA), the primary storage form of acetate in the brain, and aspartoacylase (ASPA), the enzyme responsible for NAA catalysis to generate acetate and ultimately acetyl-Coenzyme A for histone acetylation, are reduced in oligodendroglioma. The short chain triglyceride glyceryl triacetate (GTA), which increases histone acetylation and inhibits histone deacetylase expression, has been safely used for acetate supplementation in Canavan disease, a leukodystrophy due to ASPA mutation. We demonstrate that GTA induces cytostatic G0 growth arrest of oligodendroglioma-derived cells in vitro, without affecting normal cells. Sodium acetate, at doses comparable to that generated by complete GTA catalysis, but not glycerol also promoted growth arrest, whereas long chain triglycerides promoted cell growth. To begin to elucidate its mechanism of action, the effects of GTA on ASPA and acetyl-CoA synthetase protein levels and differentiation of established human oligodendroglioma cells (HOG and Hs683) and primary tumor-derived oligodendroglioma cells that exhibit some features of cancer stem cells (grade II OG33 and grade III OG35) relative to an oligodendrocyte progenitor line (Oli-Neu) were examined. The nuclear localization of ASPA and acetyl-CoA synthetase-1 in untreated cells was regulated during the cell cycle. GTA-mediated growth arrest was not associated with apoptosis or differentiation, but increased expression of acetylated proteins. Thus, GTA-mediated acetate supplementation may provide a safe, novel epigenetic therapy to reduce the growth of oligodendroglioma cells without affecting normal neural stem or oligodendrocyte progenitor cell proliferation or differentiation.

Triacetin‐based acetate supplementation as a chemotherapeutic adjuvant therapy in glioma

Cancer is associated with epigenetic (i.e., histone hypoacetylation) and metabolic (i.e., aerobic glycolysis) alterations. Levels of N-acetyl-L-aspartate (NAA), the primary storage form of acetate in the brain, and aspartoacylase (ASPA), the enzyme responsible for NAA catalysis to generate acetate, are reduced in glioma; yet, few studies have investigated acetate as a potential therapeutic agent. This preclinical study sought to test the efficacy of the food additive Triacetin (glyceryl triacetate, GTA) as a novel therapy to increase acetate bioavailability in glioma cells. The growth-inhibitory effects of GTA, compared to the histone deacetylase inhibitor Vorinostat (SAHA), were assessed in established human glioma cell lines (HOG and Hs683 oligodendroglioma, U87 and U251 glioblastoma) and primary tumor-derived glioma stem-like cells (GSCs), relative to an oligodendrocyte progenitor line (Oli-Neu), normal astrocytes, and neural stem cells (NSCs) in vitro. GTA was also tested as a chemotherapeutic adjuvant with temozolomide (TMZ) in orthotopically grafted GSCs. GTA-induced cytostatic growth arrest in vitro comparable to Vorinostat, but, unlike Vorinostat, GTA did not alter astrocyte growth and promoted NSC expansion. GTA alone increased survival of mice engrafted with glioblastoma GSCs and potentiated TMZ to extend survival longer than TMZ alone. GTA was most effective on GSCs with a mesenchymal cell phenotype. Given that GTA has been chronically administered safely to infants with Canavan disease, a leukodystrophy due to ASPA mutation, GTA-mediated acetate supplementation may provide a novel, safe chemotherapeutic adjuvant to reduce the growth of glioma tumors, most notably the more rapidly proliferating, glycolytic and hypoacetylated mesenchymal glioma tumors.

Isolation, morphological and molecular characterization of phytate-hydrolysing fungi by 18S rDNA sequence analysis

Phytate is the primary storage form of phosphate in plants. Monogastric animals like poultry, pigs and fishes have very low or no phytase activities in their digestive tracts therefore, are incapable to efficiently utilize phytate phosphorus from the feed. Phytase from microbial sources are supplemented to feedstuff of these to increase the uptake of phytate phosphorus. In the present work efforts were made to isolate and characterize proficient phytase producing fungi from soil. Phytase producing fungi were isolated using phytate specific medium. Fungal isolates were selected according to their higher phytase activities. These isolates were further characterized and identified by morphological and microscopic analysis and confirmed by amplification of 18S rRNA gene, using specific primers. This gene was subsequently sequenced and phylogenetic affiliations were assigned. Fungal isolates were identified as various species of Aspergillus. Phytases from these fungi could be utilized as a feed additive in poultry and swine industries.

Genetic analysis of two OsLpa1-like genes in Arabidopsis reveals that only one is required for wild-type seed phytic acid levels

Phytic acid (inositol-1,2,3,4,5,6-hexakisphosphate or InsP(6)) is the primary storage form of phosphorus in plant seeds. The rice OsLpa1 encodes a novel protein required for wild-type levels of seed InsP(6) and was identified from a low phytic acid (lpa) mutant exhibiting a 45-50% reduction in seed InsP(6). OsLpa1 is highly conserved in plants and Arabidopsis contains two OsLpa1-like genes, At3g45090 and At5g60760. Analysis of homozygous T-DNA insertion mutants of At5g60760 revealed significantly reduced levels of seed InsP(6) while no changes were observed in seeds of At3g45090 mutants. A double knockout mutant of At5g60760 and At3g45090 was created and its seed InsP(6) content was similar to that of the At5g60760 mutant indicating that At3g45090 does not provide functional redundancy. OsLpa1 was confirmed to be the ortholog of At5g60760 by complementation of a knockout mutant with a cDNA clone corresponding to the largest of three alternative transcripts of OsLpa1. The spatial and temporal expression of At5g60760 during seed development is consistent with its involvement in seed InsP(6) biosynthesis.

Dietary roles of phytate and phytase in human nutrition: A review

Phytate is the primary storage form of both phosphate and inositol in plant seeds. It forms complexes with dietary minerals, especially iron and zinc, and causes mineral-related deficiency in humans. It also negatively impacts protein and lipid utilisation. It is of major concern for individuals who depend mainly on plant derivative foods. Processing techniques, such as soaking, germination, malting and fermentation, reduce phytate content by increasing activity of naturally present phytase. Supplementation of phytase in diets results in increase in mineral absorption. Apart from negative effects, its consumption provides protection against a variety of cancers mediated through antioxidation properties, interruption of cellular signal transduction, cell cycle inhibition and enhancement of natural killer (NK) cells activity. It has therapeutic use against diabetes mellitus, atherosclerosis and coronary heart disease and reduces kidney stone formation, HIV-1 and heavy metal toxicity; however, information on the dosage for humans for eliciting beneficial effects is limited.

Structure of Debaryomyces castellii CBS 2923 phytase.

Phytate (myo-inositol hexakisphosphate) is the primary storage form of phosphate in seeds and legumes (Reddy et al., 1982). Phytases are phosphatases that hydrolyze phytate to less phosphorylated myo-inositol derivatives and inorganic phosphate. The crystal structure of phytase from Debaryomyces castellii has been determined at 2.3 A resolution. The crystals belonged to space group P6(5)22, with unit-cell parameters a = 121.65, c = 332.24 A. The structure was solved by molecular replacement and refined to a final R factor of 15.7% (R(free) = 20.9%). The final model consists of a dimer (with two monomers of 458 residues), five NAG molecules and 628 water molecules.