相关论文
1999 - The EMBO Journal
Loss‐of‐function mutations in the rice homeobox gene OSH15 affect the architecture of internodes resulting in dwarf plants

The rice homeobox gene OSH15 (Oryza sativa homeobox) is a member of the knotted1‐type homeobox gene family. We report here on the identification and characterization of a loss‐of‐function mutation in OSH15 from a library of retrotransposon‐tagged lines of rice. Based on the phenotype and map position, we have identified three independent deletion alleles of the locus among conventional morphological mutants. All of these recessive mutations, which are considered to be null alleles, exhibit defects in internode elongation. Introduction of a 14 kbp genomic DNA fragment that includes all exons, introns and 5′‐ and 3′‐ flanking sequences of OSH15 complemented the defects in internode elongation, confirming that they were caused by the loss‐of‐function of OSH15. Internodes of the mutants had abnormal‐shaped epidermal and hypodermal cells and showed an unusual arrangement of small vascular bundles. These mutations demonstrate a role for OSH15 in the development of rice internodes. This is the first evidence that the knotted1‐type homeobox genes have roles other than shoot apical meristem formation and/or maintenance in plant development.

1977 - The Journal of clinical investigation
Cyclic adenosine 3',5'-monophosphate inhibits the availability of arachidonate to prostaglandin synthetase in human platelet suspensions.

When thrombin is added to washed human platelets, one of its actions results in activation of a phospholipase that hydrolyzes arachidonic acid from phospholipids. The arachidonate is converted to the cyclic endoperoxides (prostaglandin G2 and prostaglandin H2) by fatty acid cyclo-oxygenase. These compounds are then converted to thromboxane A2, also called rabbit aorta-contracting substance, by thromboxane synthetase. These labile, pharmacologically active compounds then break down to inactive products including thromboxane B2 and malonaldehyde. Incubation of platelets with either dibutyryl cyclic adenosine 3',5'-monophosphate (dBcAMP) or prostaglandin E1 (PGE1) before thrombin addition blocks the subsequent formation of oxygenated products of arachidonic acid including thromboxane A2, thromboxane B2, and malonaldehyde. In contrast, when arachidonic acid is added directly to platelets, prior incubation with dBcAMP or PGE1 does not inhibit production of the prostaglandins or their metabolites. Thrombin treatment of platelets also blocks the acetylation of cyclo-oxygenase by aspirin since the hydrolyzed arachidonic acid competes with aspirin for the active site on cyclo-oxygenase. Prior treatment of platelets with dBcAMP or PGE1 reverses the thrombin inhibition of the acetylation of cyclo-oxygenase. We conclude that agents which elevate platelet cAMP levels inhibit the hydrolysis of arachidonic acid from platelet phospholipids. We also find that prostaglandin synthesis can be dissociated, in part, from platelet aggregation and release, and that cAMP has separate actions on these processes. Higher thrombin concentrations are required to stimulate prostaglandin synthesis (0.05-2 U/ml) than are required to induce [14C]serotonin release (0.02-0.1 U/ml). Furthermore, dBcAMP and PGE1 both inhibit platelet aggregation induced by either arachidonic acid or prostaglandin H2 without affecting the production of prostaglandin metabolites from these compounds.

2010 - PLoS ONE
Effect of Animal and Industrial Trans Fatty Acids on HDL and LDL Cholesterol Levels in Humans – A Quantitative Review

Background Trans fatty acids are produced either by industrial hydrogenation or by biohydrogenation in the rumens of cows and sheep. Industrial trans fatty acids lower HDL cholesterol, raise LDL cholesterol, and increase the risk of coronary heart disease. The effects of conjugated linoleic acid and trans fatty acids from ruminant animals are less clear. We reviewed the literature, estimated the effects trans fatty acids from ruminant sources and of conjugated trans linoleic acid (CLA) on blood lipoproteins, and compared these with industrial trans fatty acids. Methodology/Principal Findings We searched Medline and scanned reference lists for intervention trials that reported effects of industrial trans fatty acids, ruminant trans fatty acids or conjugated linoleic acid on LDL and HDL cholesterol in humans. The 39 studies that met our criteria provided results of 29 treatments with industrial trans fatty acids, 6 with ruminant trans fatty acids and 17 with CLA. Control treatments differed between studies; to enable comparison between studies we recalculated for each study what the effect of trans fatty acids on lipoprotein would be if they isocalorically replaced cis mono unsaturated fatty acids. In linear regression analysis the plasma LDL to HDL cholesterol ratio increased by 0.055 (95%CI 0.044–0.066) for each % of dietary energy from industrial trans fatty acids replacing cis monounsaturated fatty acids The increase in the LDL to HDL ratio for each % of energy was 0.038 (95%CI 0.012–0.065) for ruminant trans fatty acids, and 0.043 (95% CI 0.012–0.074) for conjugated linoleic acid (p = 0.99 for difference between CLA and industrial trans fatty acids; p = 0.37 for ruminant versus industrial trans fatty acids). Conclusions/Significance Published data suggest that all fatty acids with a double bond in the trans configuration raise the ratio of plasma LDL to HDL cholesterol.

2005 - Genetics
Detecting Amino Acid Sites Under Positive Selection and Purifying Selection

An excess of nonsynonymous over synonymous substitution at individual amino acid sites is an important indicator that positive selection has affected the evolution of a protein between the extant sequences under study and their most recent common ancestor. Several methods exist to detect the presence, and sometimes location, of positively selected sites in alignments of protein-coding sequences. This article describes the “sitewise likelihood-ratio” (SLR) method for detecting nonneutral evolution, a statistical test that can identify sites that are unusually conserved as well as those that are unusually variable. We show that the SLR method can be more powerful than currently published methods for detecting the location of positive selection, especially in difficult cases where the strength of selection is low. The increase in power is achieved while relaxing assumptions about how the strength of selection varies over sites and without elevated rates of false-positive results that have been reported with some other methods. We also show that the SLR method performs well even under circumstances where the results from some previous methods can be misleading.

2005 - Annual review of cell and developmental biology
Docosahexaenoic acid, fatty acid-interacting proteins, and neuronal function: breastmilk and fish are good for you.

In contrast to other tissues, the nervous system is enriched in the polyunsaturated fatty acids (PUFAs): arachidonic acid (AA, 20:4 n-6) and docosahexaenoic acid (DHA, 22:6 n-3). Despite their abundance in the nervous system, AA and DHA cannot be synthesized de novo by mammals; they, or their precursors, must be ingested from dietary sources and transported to the brain. During late gestation and the early postnatal period, neurodevelopment is exceptionally rapid, and substantial amounts of PUFAs, especially DHA, are critical to ensure neurite outgrowth as well as proper brain and retina development. Here, we review the various functions of DHA in the nervous system, the proteins involved in its internalization and metabolism into phospholipids, and its relationship to several neurological disorders, including Alzheimer's disease and depression.

2002 - Diabetes
Alterations in the activity of placental amino acid transporters in pregnancies complicated by diabetes.

Alterations in placental transport may contribute to accelerated fetal growth in pregnancies complicated by diabetes. We studied the activity of the syncytiotrophoblast amino acid transporter system A and the transport of the essential amino acids leucine, lysine, and taurine. Syncytiotrophoblast microvillous plasma membranes (MVMs) and basal plasma membranes (BMs) were isolated from placentas obtained from normal pregnancies and pregnancies complicated by gestational diabetes mellitus (GDM) and type 1 diabetes, with and without large-for-gestational-age (LGA) fetuses. Amino acid transport was assessed using radio-labeled substrates and rapid filtration techniques. System A activity in MVM was increased (65-80%, P < 0.05) in all groups with diabetes independent of fetal overgrowth. However, MVM system A activity was unaffected in placentas of normal pregnancies with LGA fetuses. MVM leucine transport was increased in the GDM/LGA group. In BMs, amino acid transport was unaffected by diabetes. In conclusion, diabetes in pregnancy is associated with an increased system A activity in MVM, and MVM leucine transport is increased in the GDM/LGA group. We suggest that these changes result in an increased uptake of neutral amino acids across MVM, which may be used in placental metabolism or be delivered to the fetus. The increased MVM leucine uptake in the GDM/LGA group may contribute to accelerated fetal growth in these patients.

2010 - Genome research
Function annotation of the rice transcriptome at single-nucleotide resolution by RNA-seq.

The functional complexity of the rice transcriptome is not yet fully elucidated, despite many studies having reported the use of DNA microarrays. Next-generation DNA sequencing technologies provide a powerful approach for mapping and quantifying the transcriptome, termed RNA sequencing (RNA-seq). In this study, we applied RNA-seq to globally sample transcripts of the cultivated rice Oryza sativa indica and japonica subspecies for resolving the whole-genome transcription profiles. We identified 15,708 novel transcriptional active regions (nTARs), of which 51.7% have no homolog to public protein data and >63% are putative single-exon transcripts, which are highly different from protein-coding genes (<20%). We found that approximately 48% of rice genes show alternative splicing patterns, a percentage considerably higher than previous estimations. On the basis of the available rice gene models, 83.1% (46,472 genes) of the current rice gene models were validated by RNA-seq, and 6228 genes were identified to be extended at the 5' and/or 3' ends by at least 50 bp. Comparative transcriptome analysis demonstrated that 3464 genes exhibited differential expression patterns. The ratio of SNPs with nonsynonymous/synonymous mutations was nearly 1:1.06. In total, we interrogated and compared transcriptomes of the two rice subspecies to reveal the overall transcriptional landscape at maximal resolution.

2005 - Journal of AOAC International
Effects of antinutritional factors on protein digestibility and amino acid availability in foods.

Digestibility of protein in traditional diets from developing countries such as India, Guatemala, and Brazil is considerably lower compared to that of protein in typical North American diets (54-78 versus 88-94%). The presence of less digestible protein fractions, high levels of insoluble fiber, and high concentrations of antinutritional factors in the diets of developing countries, which are based on less refined cereals and grain legumes as major sources of protein, are responsible for poor digestibility of protein. The effects of the presence of some of the important antinutritional factors on protein and amino digestibilities of food and feed products are reviewed in this chapter. Food and feed products may contain a number of antinutritional factors that may adversely affect protein digestibility and amino acid availability. Antinutritional factors may occur naturally, such as glucosinolates in mustard and rapeseed protein products, trypsin inhibitors and hemagglutinins in legumes, tannins in legumes and cereals, phytates in cereals and oilseeds, and gossypol in cottonseed protein products. Antinutritional factors may also be formed during heat/alkaline processing of protein products, yielding Maillard compounds, oxidized forms of sulfur amino acids, D-amino acids, and lysinoalanine (LAL, an unnatural amino acid derivative). The presence of high levels of dietary trypsin inhibitors from soybeans, kidney beans, or other grain legumes can cause substantial reductions in protein and amino acid digestibilities (up to 50%) in rats and pigs. Similarly, the presence of high levels of tannins in cereals, such as sorghum, and grain legumes, such as fababean (Vicia faba L.), can result in significantly reduced protein and amino acid digestibilities (up to 23%) in rats, poultry, and pigs. Studies involving phytase supplementation of production rations for swine or poultry have provided indirect evidence that normally encountered levels of phytates in cereals and legumes can reduce protein and amino acid digestibilities by up to 10%. D-amino acids and LAL formed during alkaline/heat treatment of proteins such as casein, lactalbumin, soy protein isolate, or wheat proteins are poorly digestible (less than 40%), and their presence can reduce protein digestibility by up to 28% in rats and pigs. A comparison of the protein digestibility determination in young (5-week) versus old (20-month) rats suggests greater susceptibility to the adverse effects of antinutritional factors in old rats than in young rats. Therefore, the inclusion of protein digestibility data obtained with young rats, as the recommended animal model, in the calculation of PDCAAS (Protein Digestibility-Corrected Amino Acid Score) may overestimate protein digestibility and quality of products, especially those containing antinutritional factors, for the elderly. For products specifically intended for the elderly, protein digestibility should be determined using more mature rats.

1977 - Science
Posttranslational covalent modification of proteins.

A search for derivatized amino acids in proteins has shown that the extent of posttranslational modification of proteins is quite substantial. While only 20 primary amino acids are specified in the genetic code and are involved as monomer building blocks in the assembly of the polypeptide chain, about 140 amino acids and amino acid derivatives have been identified as constituents of different proteins in different organisms. A brief consideration of the questions about where and when the derivatization reactions occur, how the specificity of the reactions is established, and how the posttranslational modifications can facilitate biological processes, reveal a need for more information on all these points. Answers to these questions should represent significant contributions to our understanding of biochemistry and cell biology.

1975 - Nature
Stereochemical basis of heat stability in bacterial ferredoxins and in haemoglobin A2

MOST enzymes are quickly inactivated above about 55 °C but those from thermophile bacteria are stable for long periods at higher temperatures1. We do not know why because so far their structures have proved too complex. For example although the tertiary and quaternary structures of the enzyme glyceraldehyde phosphate dehydrogenase from lobster muscle and from Bacterium stearothermophilus are alike their amino acid sequences differ by more than 130 out of some 330 positions which makes it hard to decide why the stearothermophilus enzyme is more stable. The electron transfer protein ferredoxin offers a better chance because its single polypeptide chain contains fewer than 60 residues; its structure is known and its heat stability and amino acid sequence have been determined in both mesophile and thermophile bacteria. We have built an atomic model of this protein, replaced its amino acid side chains in turn to correspond to the published sequences and searched for possible causes of the greater heat stability of ferredoxins from thermophile bacteria. We found that it arises mainly from external salt bridges linking residues near the amino terminus to others near the carboxy terminus. Haemoglobin A2 a minor fraction of adult human haemoglobin which is a little more heat stable than the major fraction, haemoglobin A, seemed another good choice because its amino acid sequence differs from that of A at only 10 positions. The atomic model suggests that at only two of these positions are the replacements likely to contribute to the extra stability of haemoglobin A2 one replacement providing an extra hydrogen bond between the α1 and β1 subunits and the other adding two non-polar interactions to a surface crevice within the β subunits. To account for the increased heat stability of the two proteins the extra bond energy provided by these interactions need not be larger than 10 kJ for ferredoxin or 5 kJ for haemoglobin A2.

1969 - The Journal of clinical investigation
Amino acid balance across tissues of the forearm in postabsorptive man. Effects of insulin at two dose levels.

Amino acid balance across skeletal muscle and across subcutaneous adipose tissue plus skin of the forearm has been quantified in postabsorptive man before and after insulin infusion into the brachial artery. Skeletal muscle released significant amounts of alpha amino nitrogen after an overnight fast. Most individual amino acids were released. Alanine output was by far the greatest. The pattern of release probably reflects both the composition of muscle protein undergoing degradation and de novo synthesis of alanine by transamination. A significant correlation was observed between the extent of release of each amino acid and its ambient arterial concentration. Elevation of forearm insulin in eight subjects from postabsorptive (12 muU/ml) to high physiologic levels (157 muU/ml) in addition to stimulating muscle glucose uptake blocked muscle alpha amino nitrogen release by 74%. Consistent declines in output were seen for leucine, isoleucine, tyrosine, phenylalanine, threonine, glycine, and alpha-aminobutyric acid. Alanine output was insignificantly affected. Doubling forearm insulin levels (from 10 to 20 muU/ml) in eight subjects increased muscle glucose uptake in three and blocked alpha amino nitrogen output in two although both effects were seen concurrently in only one subject. Changes in net amino acid balance after insulin could be accounted for by increased transport of amino acids into muscle cells or retardation of their exit. It is likely that ambient arterial amino acid concentrations are established and maintained primarily by the extent of muscle amino acid release. The individual amino acids whose outputs from forearm muscle decline after forearm insulinization correspond well with those whose levels fall systematically after systemic insulinization. This suggests that declines in amino acid levels after systemic insulinization are due to inhibition of muscle release. Doubling basal insulin approaches the threshold both for blockade of muscle amino acid output and stimulation of glucose uptake, effects which appear to occur independently.

2003 - The American journal of clinical nutrition
Plant-based foods and prevention of cardiovascular disease: an overview.

Evidence from prospective cohort studies indicates that a high consumption of plant-based foods such as fruit and vegetables, nuts, and whole grains is associated with a significantly lower risk of coronary artery disease and stroke. The protective effects of these foods are probably mediated through multiple beneficial nutrients contained in these foods, including mono- and polyunsaturated fatty acids, n-3 fatty acids, antioxidant vitamins, minerals, phytochemicals, fiber, and plant protein. In dietary practice, healthy plant-based diets do not necessarily have to be low in fat. Instead, these diets should include unsaturated fats as the predominant form of dietary fat (eg, fats from natural liquid vegetable oils and nuts), whole grains as the main form of carbohydrate, an abundance of fruit and vegetables, and adequate n-3 fatty acids. Such diets, which also have many other health benefits, deserve more emphasis in dietary recommendations to prevent chronic diseases.

2002 - Proceedings of the National Academy of Sciences of the United States of America
Metabolic efficiency and amino acid composition in the proteomes of Escherichia coli and Bacillus subtilis

Biosynthesis of an Escherichia coli cell, with organic compounds as sources of energy and carbon, requires approximately 20 to 60 billion high-energy phosphate bonds [Stouthamer, A. H. (1973) Antonie van Leeuwenhoek 39, 545–565]. A substantial fraction of this energy budget is devoted to biosynthesis of amino acids, the building blocks of proteins. The fueling reactions of central metabolism provide precursor metabolites for synthesis of the 20 amino acids incorporated into proteins. Thus, synthesis of an amino acid entails a dual cost: energy is lost by diverting chemical intermediates from fueling reactions and additional energy is required to convert precursor metabolites to amino acids. Among amino acids, costs of synthesis vary from 12 to 74 high-energy phosphate bonds per molecule. The energetic advantage to encoding a less costly amino acid in a highly expressed gene can be greater than 0.025% of the total energy budget. Here, we provide evidence that amino acid composition in the proteomes of E. coli and Bacillus subtilis reflects the action of natural selection to enhance metabolic efficiency. We employ synonymous codon usage bias as a measure of translation rates and show increases in the abundance of less energetically costly amino acids in highly expressed proteins.

1993 - Journal of Biomolecular NMR
Amino acid type determination in the sequential assignment procedure of uniformly 13C/15N-enriched proteins

SummaryExperiments and procedures are described that greatly alleviate the sequential assignment process of uniformly 13C/15N-enriched proteins by determining the type of amino acid from experiments that correlate side chain with backbone amide resonances. A recently proposed 3D NMR experiment, CBCA(CO)NH, correlates Cα and Cβ resonances to the backbone amide 1H and 15N resonances of the next residue (Grzesiek, S. and Bax, A. (1992) J. Am. Chem. Soc., 114, 6291–6293). An extension of this experiment is described which correlates the proton Hβ and Hα resonances to the amide 1H and 15N resonances of the next amino acid, and a detailed product operator description is given. A simple 2D-edited constant-time HSQC experiment is described which rapidly identifies Hβ and Cβ resonances of aromatic or Asn/Asp residues. The extent to which combined knowledge of the Cα and Cβ chemical shift values determines the amino acid type is investigated, and it is demonstrated that the combined Cα and Cβ chemical shifts of three or four adjacent residues usually are sufficient for defining a unique position in the protein sequence.

1997 - Science
Enantiomeric Excesses in Meteoritic Amino Acids

Gas chromatographic-mass spectral analyses of the four stereoisomers of 2-amino-2,3-dimethylpentanoic acid (DL-α-methylisoleucine and DL-α-methylalloisoleucine) obtained from the Murchison meteorite show that the L enantiomer occurs in excess (7.0 and 9.1%, respectively) in both of the enantiomeric pairs. Similar results were obtained for two other α-methyl amino acids, isovaline and α-methylnorvaline, although the α hydrogen analogs of these amino acids, α-amino-n-butyric acid and norvaline, were found to be racemates. With the exception of α-amino-n-butyric acid, these amino acids are either unknown or of limited occurrence in the biosphere. Because carbonaceous chondrites formed 4.5 billion years ago, the results are indicative of an asymmetric influence on organic chemical evolution before the origin of life.

1997 - The American journal of clinical nutrition
n-3 fatty acids and serum lipoproteins: animal studies.

This review examines the effects of n-3 fatty acids on serum lipid and lipoprotein concentrations in seven species of experimental animals. n-3 Fatty acids consistently lower serum triacylglycerol concentrations in humans but not in most animals. In addition, a common effect of n-3 fatty acids in animals is a marked reduction in high-density-lipoprotein-cholesterol concentrations, a response virtually never seen with fish-oil supplementation in humans. These differences between animals and humans arise not only from underlying species differences in lipoprotein metabolism but also from differences in experimental designs, the most notable of which is the tendency to feed animals much larger amounts of n-3 fatty acids than supplements provide for humans. Thus, great care must be taken not only to use appropriate animal models when studying lipoprotein metabolism but also to feed the animals comparable amounts of n-3 fatty acids. Failure to properly address these issues will make it difficult to uncover the biochemical basis for the hypolipidemic effect of fish oils in humans through use of experimental animals.

2011 - Science
mTORC1 Senses Lysosomal Amino Acids Through an Inside-Out Mechanism That Requires the Vacuolar H+-ATPase

Cellular sensing of amino acids occurs at the lysosome and is mediated by the vacuolar proton pump. The mTOR complex 1 (mTORC1) protein kinase is a master growth regulator that is stimulated by amino acids. Amino acids activate the Rag guanosine triphosphatases (GTPases), which promote the translocation of mTORC1 to the lysosomal surface, the site of mTORC1 activation. We found that the vacuolar H+–adenosine triphosphatase ATPase (v-ATPase) is necessary for amino acids to activate mTORC1. The v-ATPase engages in extensive amino acid–sensitive interactions with the Ragulator, a scaffolding complex that anchors the Rag GTPases to the lysosome. In a cell-free system, ATP hydrolysis by the v-ATPase was necessary for amino acids to regulate the v-ATPase-Ragulator interaction and promote mTORC1 translocation. Results obtained in vitro and in human cells suggest that amino acid signaling begins within the lysosomal lumen. These results identify the v-ATPase as a component of the mTOR pathway and delineate a lysosome-associated machinery for amino acid sensing.

1998 - The Journal of Biological Chemistry
Amino Acid Sufficiency and mTOR Regulate p70 S6 Kinase and eIF-4E BP1 through a Common Effector Mechanism*

The present study identifies the operation of a signal tranduction pathway in mammalian cells that provides a checkpoint control, linking amino acid sufficiency to the control of peptide chain initiation. Withdrawal of amino acids from the nutrient medium of CHO-IR cells results in a rapid deactivation of p70 S6 kinase and dephosphorylation of eIF-4E BP1, which become unresponsive to all agonists. Readdition of the amino acid mixture quickly restores the phosphorylation and responsiveness of p70 and eIF-4E BP1 to insulin. Increasing the ambient amino acids to twice that usually employed increases basal p70 activity to the maximal level otherwise attained in the presence of insulin and abrogates further stimulation by insulin. Withdrawal of most individual amino acids also inhibits p70, although with differing potency. Amino acid withdrawal from CHO-IR cells does not significantly alter insulin stimulation of tyrosine phosphorylation, phosphotyrosine-associated phosphatidylinositol 3-kinase activity, c-Akt/protein kinase B activity, or mitogen-activated protein kinase activity. The selective inhibition of p70 and eIF-4E BP1 phosphorylation by amino acid withdrawal resembles the response to rapamycin, which prevents p70 reactivation by amino acids, indicating that mTOR is required for the response to amino acids. A p70 deletion mutant, p70Δ2–46/ΔCT104, that is resistant to inhibition by rapamycin (but sensitive to wortmannin) is also resistant to inhibition by amino acid withdrawal, indicating that amino acid sufficiency and mTOR signal to p70 through a common effector, which could be mTOR itself, or an mTOR-controlled downstream element, such as a protein phosphatase.

2010 - The Journal of Biological Chemistry
Arachidonic Acid-metabolizing Cytochrome P450 Enzymes Are Targets of ω-3 Fatty Acids*

Eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) protect against cardiovascular disease by largely unknown mechanisms. We tested the hypothesis that EPA and DHA may compete with arachidonic acid (AA) for the conversion by cytochrome P450 (CYP) enzymes, resulting in the formation of alternative, physiologically active, metabolites. Renal and hepatic microsomes, as well as various CYP isoforms, displayed equal or elevated activities when metabolizing EPA or DHA instead of AA. CYP2C/2J isoforms converting AA to epoxyeicosatrienoic acids (EETs) preferentially epoxidized the ω-3 double bond and thereby produced 17,18-epoxyeicosatetraenoic (17,18-EEQ) and 19,20-epoxydocosapentaenoic acid (19,20-EDP) from EPA and DHA. We found that these ω-3 epoxides are highly active as antiarrhythmic agents, suppressing the Ca2+-induced increased rate of spontaneous beating of neonatal rat cardiomyocytes, at low nanomolar concentrations. CYP4A/4F isoforms ω-hydroxylating AA were less regioselective toward EPA and DHA, catalyzing predominantly ω- and ω minus 1 hydroxylation. Rats given dietary EPA/DHA supplementation exhibited substantial replacement of AA by EPA and DHA in membrane phospholipids in plasma, heart, kidney, liver, lung, and pancreas, with less pronounced changes in the brain. The changes in fatty acids were accompanied by concomitant changes in endogenous CYP metabolite profiles (e.g. altering the EET/EEQ/EDP ratio from 87:0:13 to 27:18:55 in the heart). These results demonstrate that CYP enzymes efficiently convert EPA and DHA to novel epoxy and hydroxy metabolites that could mediate some of the beneficial cardiovascular effects of dietary ω-3 fatty acids.

1995 - The Journal of Biological Chemistry
Cloning of a Protein That Mediates Transcriptional Effects of Fatty Acids in Preadipocytes

Exposure of preadipocytes to long chain fatty acids induces expression of several gene markers of adipocyte differentiation. This report describes the cloning, from a preadipocyte library, of a cDNA encoding a fatty acid-activated receptor, FAAR. The cDNA had the characteristics and ligand-binding domains of nuclear hormone receptors and encoded a 440 amino acid protein related to peroxisome proliferator-activated receptors, PPAR. The deduced protein sequence was 88% homologous to that of hNUC I, isolated from human osteosarcoma cells. FAAR mRNA was abundant in adipose tissue, intestine, brain, heart, and skeletal muscles and less abundant in kidney, liver, testis, and spleen. The mRNA was undetectable in growing Ob1771 and 3T3-F442A preadipocytes, was strongly induced early during differentiation, and was increased by fatty acid. Transcription assays using hybrid receptor showed strong stimulation by fatty acid and weaker induction by fibrates. Transfection of 3T3-C2 fibroblasts, with a FAAR expression vector, conferred fatty acid inducibility of the adipocyte lipid-binding protein and the fatty acid transporter. Transcriptional induction of these genes exhibited inducer specificity identical to that described in preadipocytes. In summary, the data indicate that FAAR is likely a mediator of fatty acid transcriptional effects in preadipocytes.

Unintended compositional changes in transgenic rice seeds ( Oryza sativa L.) studied by spectral and chromatographic analysis coupled with chemometrics methods.

Zhuo Zhang
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Gong-ke Li
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Zhe Jiao
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Xiao-xi Si
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Gong-ke Li
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Zhuo-min Zhang
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Xin-ping Xu
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Xiao-xi Si
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Zhe-xu Jiao
|
Xin-ping Xu
|
Xiaoxi Si

Abstract:Unintended compositional changes in transgenic rice seeds were studied by near-infrared reflectance, GC-MS, HPLC, and ICP-AES coupled with chemometrics strategies. Three kinds of transgenic rice with resistance to fungal diseases or insect pests were comparatively studied with the nontransgenic counterparts in terms of key nutrients such as protein, amino acids, fatty acids, vitamins, elements, and antinutrient phytic acid recommended by the Organization for Economic Co-operation and Development (OECD). The compositional profiles were discriminated by chemometrics methods, and the discriminatory compounds were protein, three amino acids, two fatty acids, two vitamins, and several elements. Significance of differences for these compounds was proved by analysis of variance, and the variation extent ranged from 20 to 74% for amino acids, from 19 to 38% for fatty acids, from 25 to 57% for vitamins, from 20 to 50% for elements, and 25% for protein, whereas phytic acid content did not change significantly. The unintended compositional alterations as well as unintended change of physical characteristic in transgenic rice compared with nontransgenic rice might be related to the genetic transformation, the effect of which needs to be elucidated by additional studies.

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引用
Assessment of peanut quality and compositional characteristics among transgenic sclerotinia blight-resistant and non-transgenic susceptible cultivars.
Journal of Agricultural and Food Chemistry
2014
Metabolite profiles of rice cultivars containing bacterial blight-resistant genes are distinctive from susceptible rice.
Acta biochimica et biophysica Sinica
2012
Long term toxicity of a Roundup herbicide and a Roundup-tolerant genetically modified maize.
Food and chemical toxicology : an international journal published for the British Industrial Biological Research Association
2012
Analysis and Identification of Rice Adulteration Using Terahertz Spectroscopy and Pattern Recognition Algorithms
IEEE Access
2020
Metabolomics of Genetically Modified Crops
International journal of molecular sciences
2014
Application of terahertz spectroscopy imaging for discrimination of transgenic rice seeds with chemometrics.
Food chemistry
2016
Nondestructive determination of transgenic Bacillus thuringiensis rice seeds (Oryza sativa L.) using multispectral imaging and chemometric methods.
Food chemistry
2014
Metabolic profiling based on LC/MS to evaluate unintended effects of transgenic rice with cry1Ac and sck genes
Plant Molecular Biology
2012
Metabolomics for the safety assessment of genetically modified (GM) crops
2013
Foodomics strategies for the analysis of transgenic foods
2013
Rice Seed Cultivar Identification Using Near-Infrared Hyperspectral Imaging and Multivariate Data Analysis
Sensors
2013
Evaluation of Genetically Engineered Crops Using Transcriptomic, Proteomic, and Metabolomic Profiling Techniques
Plant Physiology
2011
Development and characterization of GR2E Golden rice introgression lines
Scientific Reports
2021
Recent Applications of 1D GC-MS and 2D GC-MS in Foodomics Studies
2021
An Overview of Near Infrared Spectroscopy and Its Applications in the Detection of Genetically Modified Organisms
International journal of molecular sciences
2021
Metabolomics-Assisted Breeding for Crop Improvement: An Emerging Approach
2021
Recent advances in untargeted and targeted approaches applied in herbal-extracts and essential-oils fingerprinting - A review.
Journal of pharmaceutical and biomedical analysis
2020
Preliminary study on discrimination of transgenic cotton seeds using terahertz time‐domain spectroscopy
Food science & nutrition
2020
A Comparison Between the Agricultural Traits of GM and Non-GM Rice in Drought Stress and Non-stress Conditions
2020
Global metabolite profiling based on GC–MS and LC–MS/MS analyses in ABF3-overexpressing soybean with enhanced drought tolerance
Applied Biological Chemistry
2019