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Sample records for acid residues essential

  1. Identification of essential amino acid residues of an alpha-amylase inhibitor from Phaseolus vulgaris white kidney beans.

    PubMed

    Takahashi, T; Hiramoto, S; Wato, S; Nishimoto, T; Wada, Y; Nagai, K; Yamaguchi, H

    1999-11-01

    Kidney bean (Phaseolus vulgaris) alpha-amylase inhibitors, which are bivalent inhibitors with the subunit stoichiometry of (alphabeta)(2) complex, have been inferred to contain unique arginine, tryptophan, and tyrosine residues essential for the inhibitory activity. To test the validity of this inference, an attempt was made to identify the essential amino acid residues of a white kidney bean (P. vulgaris) alpha-amylase inhibitor (PHA-I) by using the chemical modification technique combined with amino acid sequencing and mass spectrometry. Exhaustive modification of the arginine residues by phenylglyoxal did not lead to a marked loss of activity, suggesting that no arginine residue is directly associated with the inhibitory activity. N-Bromosuccinimide treatment of PHA-I in the presence or absence of a substrate alpha-amylase revealed the involvement of two tryptophan residues in alpha-amylase inhibition, and they were identified as Trp188 of the beta-subunit by amino acid sequencing and mass spectrometry of lysylendopeptidase peptides. Further, two tyrosine residues were preferentially modified either by N-acetylimidazole or by tetranitromethane, resulting in a concomitant loss of most of the PHA-I activity. Amino acid sequencing of the lysylendopeptidase peptides from a tetranitromethane-modified PHA-I identified Tyr186 of the beta-subunit as an essential residue.

  2. Basic amino acid residues located in the N-terminal region of BEND3 are essential for its nuclear localization.

    PubMed

    Shiheido, Hirokazu; Shimizu, Jun

    2015-02-20

    BEN domain-containing protein 3 (BEND3) has recently been reported to function as a heterochromatin-associated protein in transcriptional repression in the nucleus. BEND3 should have nuclear localization signals (NLSs) to localize to the nucleus in light of its molecular weight, which is higher than that allowed to pass through nuclear pore complexes. We here analyzed the subcellular localization of deletion/site-directed mutants of human BEND3 by an immunofluorescence assay in an attempt to identify the amino acids essential for its nuclear localization. We found that three basic amino acid residues located in the N-terminal region of BEND3 (BEND356-58, KRK) are essential, suggesting that these residues play a role as a functional NLS. These results provide valuable information for progressing research on BEND3.

  3. Basic amino acid residues located in the N-terminal region of BEND3 are essential for its nuclear localization

    SciTech Connect

    Shiheido, Hirokazu Shimizu, Jun

    2015-02-20

    BEN domain-containing protein 3 (BEND3) has recently been reported to function as a heterochromatin-associated protein in transcriptional repression in the nucleus. BEND3 should have nuclear localization signals (NLSs) to localize to the nucleus in light of its molecular weight, which is higher than that allowed to pass through nuclear pore complexes. We here analyzed the subcellular localization of deletion/site-directed mutants of human BEND3 by an immunofluorescence assay in an attempt to identify the amino acids essential for its nuclear localization. We found that three basic amino acid residues located in the N-terminal region of BEND3 (BEND3{sub 56–58}, KRK) are essential, suggesting that these residues play a role as a functional NLS. These results provide valuable information for progressing research on BEND3. - Highlights: • BEND3 localizes to the nucleus. • The N-terminal 60 amino acids region of BEND3 contains NLS. • Amino acids located between 56 and 58 of BEND3 (KRK) are part of NLS. • KRK motif is highly conserved among BEND3 homologs.

  4. Newly identified essential amino acid residues affecting ^8-sphingolipid desaturase activity revealed by site-directed mutagenesis

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In order to identify amino acid residues crucial for the enzymatic activity of ^8-sphingolipid desaturases, a sequence comparison was performed among ^8-sphingolipid desaturases and ^6-fatty acid desaturase from various plants. In addition to the known conserved cytb5 (cytochrome b5) HPGG motif and...

  5. Functional analysis of amino acid residues essential for activity in the Na+/H+ exchanger of fission yeast.

    PubMed

    Dibrov, P; Young, P G; Fliegel, L

    1998-06-09

    We identified amino acid residues important for activity of sod2, the Na+/H+ antiporter of Schizosaccharomyces pombe. We mutated all eight His residues of sod2 into Arg. Only His367-->Arg affected function and resulted in complete inability of sod2 to allow growth of S. pombe in LiCl-containing medium. Mutant S. pombe (H367R) could not expel sodium in acidic (pH 4.0) medium and were defective in their ability to alkalinize external medium. When His367 was replaced by Asp, sodium export of S. pombe was suppressed at acidic pH while the sodium-dependent proton influx at pH 6.1 was increased compared to wild type. We also mutated three residues conserved in putative membrane regions of various eukaryotic and prokaryotic Na+/H+ exchangers. S. pombe containing Asp241-->Asn and Asp266, 267-->Asn mutations had greatly impaired growth in LiCl-containing medium. In addition, sodium-dependent proton influx at external pH 6. 1 was impaired. Sodium export from S. pombe cells at external pH 4.0 was also almost completely abolished by the D266,267N mutation; however, the D241N mutant protein retained almost normal Na+ export. The results demonstrate that His367, Asp241, and Asp266,267 are important in the function of the eukaryotic Na+/H+ exchanger sod2.

  6. Conformational study reveals amino acid residues essential for hemagglutinating and anti-proliferative activities of Clematis montana lectin.

    PubMed

    Lu, Bangmin; Zhang, Bin; Qi, Wei; Zhu, Yanan; Zhao, Yan; Zhou, Nan; Sun, Rong; Bao, Jinku; Wu, Chuanfang

    2014-11-01

    Clematis montana lectin (CML), a novel mannose-binding lectin purified from C. montana Buch.-Ham stem (Ranunculaceae), has been proved to have hemagglutinating activity in rabbit erythrocytes and apoptosis-inducing activity in tumor cells. However, the biochemical properties of CML have not revealed and its structural information still needs to be elucidated. In this study, it was found that CML possessed quite good thermostability and alkaline resistance, and its hemagglutinating activity was bivalent metal cation dependent. In addition, hemagglutination test and fluorescence spectroscopy proved that GuHCl, urea, and sodium dodecyl sulfate could change the conformation of CML and further caused the loss of hemagglutination activity. Moreover, the changes of fluorescence spectrum indicated that the tryptophan (Trp) microenvironment conversion might be related to the conformation and bioactivities of CML. In addition, it was also found that Trp residues, arginine (Arg) residues, and sulfhydryl were important for the hemagglutinating activity of CML, but only Trp was proved to be crucial for the CML conformation. Furthermore, the Trp, Arg, and sulfhydryl-modified CML exhibited 97.17%, 76.99%, and 49.64% loss of its anti-proliferative activity, respectively, which was consistent with the alterations of its hemagglutinating activity. Given these findings, Trp residues on the surface of CML are essential for the active center to form substrate-accessible conformation and suitable environment for carbohydrate binding.

  7. Amino acid residues in ribonuclease MC1 from bitter gourd seeds which are essential for uridine specificity.

    PubMed

    Numata, T; Suzuki, A; Yao, M; Tanaka, I; Kimura, M

    2001-01-16

    The ribonuclease MC1 (RNase MC1), isolated from seeds of bitter gourd (Momordica charantia), consists of 190 amino acids and is characterized by specific cleavage at the 5'-side of uridine. Site-directed mutagenesis was used to evaluate the contribution of four amino acids, Asn71, Val72, Leu73, and Arg74, at the alpha4-alpha5 loop between alpha4 and alpha5 helices for recognition of uracil base by RNase MC1. Four mutants, N71T, V72L, L73A, and R74S, in which Asn71, Val72, Leu73, and Arg74 in RNase MC1 were substituted for the corresponding amino acids, Thr, Leu, Ala, and Ser, respectively, in a guanylic acid preferential RNase NW from Nicotiana glutinosa, were prepared and characterized with respect to enzymatic activity. Kinetic analysis with a dinucleoside monophosphate, CpU, showed that the mutant N71T exhibited 7.0-fold increased K(m) and 2.3-fold decreased k(cat), while the mutant L73A had 14.4-fold increased K(m), although it did retain the k(cat) value comparable to that of the wild-type. In contrast, replacements of Val72 and Arg74 by the corresponding amino acids Leu and Ser, respectively, had little effect on the enzymatic activity. This observation is consistent with findings in the crystal structure analysis that Asn71 and Leu73 are responsible for a uridine specificity for RNase MC1. The role of Asn71 in enzymatic reaction of RNase MC1 was further investigated by substituting amino acids Ala, Ser, Gln, and Asp. Our observations suggest that Asn71 has at least two roles: one is base recognition by hydrogen bonding, and the other is to stabilize the conformation of the alpha4-alpha5 loop by hydrogen bonding to the peptide backbone, events which possibly result in an appropriate orientation of the alpha-helix (alpha5) containing active site residues. Mutants N71T and N71S showed a remarkable shift from uracil to guanine specificity, as evaluated by cleavage of CpG, although they did exhibit uridine specificity against yeast RNA and homopolynucleotides.

  8. Discovery of essential fatty acids

    PubMed Central

    Spector, Arthur A.; Kim, Hee-Yong

    2015-01-01

    Dietary fat was recognized as a good source of energy and fat-soluble vitamins by the first part of the 20th century, but fatty acids were not considered to be essential nutrients because they could be synthesized from dietary carbohydrate. This well-established view was challenged in 1929 by George and Mildred Burr who reported that dietary fatty acid was required to prevent a deficiency disease that occurred in rats fed a fat-free diet. They concluded that fatty acids were essential nutrients and showed that linoleic acid prevented the disease and is an essential fatty acid. The Burrs surmised that other unsaturated fatty acids were essential and subsequently demonstrated that linolenic acid, the omega-3 fatty acid analog of linoleic acid, is also an essential fatty acid. The discovery of essential fatty acids was a paradigm-changing finding, and it is now considered to be one of the landmark discoveries in lipid research. PMID:25339684

  9. Identification of amino acid residues essential for catalytic activity of gentisate 1,2-dioxygenase from Pseudomonas alcaligenes NCIB 9867.

    PubMed

    Chua, C H; Feng, Y; Yeo, C C; Khoo, H E; Poh, C L

    2001-10-16

    Gentisate 1,2-dioxygenase (GDO, EC 1.13.11.4) is a ring cleavage enzyme that utilizes gentisate as a substrate yielding maleylpyruvate as the ring fission product. Mutant GDOs were generated by both random mutagenesis and site-directed mutagenesis of the gene cloned from Pseudomonas alcaligenes NCIB 9867. Alignment of known GDO sequences indicated the presence of a conserved central core region. Mutations generated within this central core resulted in the complete loss of enzyme activity whereas mutations in the flanking regions yielded GDOs with enzyme activities that were reduced by up to 78%. Site-directed mutagenesis was also performed on a pair of highly conserved HRH and HXH motifs found within this core region. Conversion of these His residues to Asp resulted in the complete loss of catalytic activity. Mutagenesis within the core region could have affected quaternary structure formation as well as cofactor binding. A mutant enzyme with increased catalytic activities was also characterized.

  10. An essential tyrosine residue of Aspergillus polygalacturonase.

    PubMed

    Stratilová, E; Dzúrová, M; Markovic, O; Jörnvall, H

    1996-03-11

    Based on strict conservation of a tyrosine residue in 24 polygalacturonases, tyrosine modification was assessed in two different forms of the Aspergillus enzyme. The second subform was unknown in structure but submitted to sequence analysis and was found also to have the conserved tyrosine residue. Results of chemical modifications are consistent in showing inactivation of the proteins with all tyrosine-reactive agents tested, acetic anhydride, N-acetyl imidazole, and tetranitromethane. Furthermore, after acetylation, regeneration of enzyme activity was possible with hydroxylamine. Spectrophotometric pH titration showed that one accessible tyrosine residue is ionized at pH 9.3-9.5, whereas the remaining, masked residues are all ionized at pH 10.5. It is concluded that one tyrosine residue is catalytically important, in agreement with the inactivation and reactivation data, that this residue is accessible, and that it is likely to correspond to the strictly conserved residue observed in all forms.

  11. Consequences of Essential Fatty Acids

    PubMed Central

    Lands, Bill

    2012-01-01

    Essential fatty acids (EFA) are nutrients that form an amazingly large array of bioactive mediators that act on a large family of selective receptors. Nearly every cell and tissue in the human body expresses at least one of these receptors, allowing EFA-based signaling to influence nearly every aspect of human physiology. In this way, the health consequences of specific gene-environment interactions with these nutrients are more extensive than often recognized. The metabolic transformations have similar competitive dynamics for the n-3 and n-6 homologs when converting dietary EFA from the external environment of foods into the highly unsaturated fatty acid (HUFA) esters that accumulate in the internal environment of cells and tissues. In contrast, the formation and action of bioactive mediators during tissue responses to stimuli tend to selectively create more intense consequences for n-6 than n-3 homologs. Both n-3 and n-6 nutrients have beneficial actions, but many common health disorders are undesired consequences of excessive actions of tissue n-6 HUFA which are preventable. This review considers the possibility of preventing imbalances in dietary n-3 and n-6 nutrients with informed voluntary food choices. That action may prevent the unintended consequences that come from eating imbalanced diets which support excessive chronic actions of n-6 mediators that harm human health. The consequences from preventing n-3 and n-6 nutrient imbalances on a nationwide scale may be very large, and they need careful evaluation and implementation to avoid further harmful consequences for the national economy. PMID:23112921

  12. The C-terminal 18 Amino Acid Region of Dengue Virus NS5 Regulates its Subcellular Localization and Contains a Conserved Arginine Residue Essential for Infectious Virus Production

    PubMed Central

    Ng, Ivan H. W.; Chan, Kitti W. K.; Zhao, Yongqian; Ooi, Eng Eong; Lescar, Julien; Jans, David A.; Forwood, Jade K.

    2016-01-01

    Dengue virus NS5 is the most highly conserved amongst the viral non-structural proteins and is responsible for capping, methylation and replication of the flavivirus RNA genome. Interactions of NS5 with host proteins also modulate host immune responses. Although replication occurs in the cytoplasm, an unusual characteristic of DENV2 NS5 is that it localizes to the nucleus during infection with no clear role in replication or pathogenesis. We examined NS5 of DENV1 and 2, which exhibit the most prominent difference in nuclear localization, employing a combination of functional and structural analyses. Extensive gene swapping between DENV1 and 2 NS5 identified that the C-terminal 18 residues (Cter18) alone was sufficient to direct the protein to the cytoplasm or nucleus, respectively. The low micromolar binding affinity between NS5 Cter18 and the nuclear import receptor importin-alpha (Impα), allowed their molecular complex to be purified, crystallised and visualized at 2.2 Å resolution using x-ray crystallography. Structure-guided mutational analysis of this region in GFP-NS5 clones of DENV1 or 2 and in a DENV2 infectious clone reveal residues important for NS5 subcellular localization. Notably, the trans conformation adopted by Pro-884 allows proper presentation for binding Impα and mutating this proline to Thr, as present in DENV1 NS5, results in mislocalizaion of NS5 to the cytoplasm without compromising virus fitness. In contrast, a single mutation to alanine at NS5 position R888, a residue conserved in all flaviviruses, resulted in a completely non-viable virus, and the R888K mutation led to a severely attenuated phentoype, even though NS5 was located in the nucleus. R888 forms a hydrogen bond with Y838 that is also conserved in all flaviviruses. Our data suggests an evolutionarily conserved function for NS5 Cter18, possibly in RNA interactions that are critical for replication, that is independent of its role in subcellular localization. PMID:27622521

  13. Multiple ligand-binding properties of the lipocalin member chicken alpha1-acid glycoprotein studied by circular dichroism and electronic absorption spectroscopy: the essential role of the conserved tryptophan residue.

    PubMed

    Zsila, Ferenc; Matsunaga, Hisami; Bikádi, Zsolt; Haginaka, Jun

    2006-08-01

    Multiple ligand-binding properties of the 30-kDa chicken alpha(1)-acid glycoprotein (cAGP), a member of the lipocalin protein family, were investigated for the first time by using circular dichroism (CD) and UV/Vis absorption spectroscopy methods. By measuring induced CD (ICD) spectra, high-affinity binding (K(a) approximately 10(5)-10(6) M(-1)) of several drugs, dyes and natural compounds to cAGP was demonstrated including antimalarial agents (quinacrine, primaquine), phenotiazines (chlorpromazine, methylene blue), propranolol, non-steroidal antiinflammatory drugs (ketoprofen, diclofenac), tamoxifen, diazepam, tacrine, dicoumarol, cationic dyes (auramine O, thioflavine T, ethidium bromide), benzo[a]pyrene, L-thyroxine, bile pigments (bilirubin, biliverdin), alkaloids (piperine, aristolochic acid), saturated and unsaturated fatty acids. Analysis of the extrinsic CD spectra with the study of the covalently modified protein and CD displacement experiments revealed that a single Trp26 residue of cAGP conserved in the whole lipocalin family is part of the binding site, and it is essentially involved in the ligand-binding process via pi-pi stacking interaction resulting in the appearance of strong induced CD bands due to the non-degenerate intermolecular exciton coupling between the pi-pi* transitions of the stacked indole ring-ligand chromophore. The finding that cAGP is able to accommodate a broad spectrum of ligands belonging to different chemical classes suggests that its core beta-barrel cavity is unusually wide containing overlapping sub-sites. Significance of these new data in understanding of the ligand-binding properties of other lipocalins, especially that of human AGP, and potential practical applications are briefly discussed. Overall, cAGP serves as a simple, ultimate model to extend our knowledge on ligand-binding properties of lipocalins and to study the role of tryptophan residues in molecular recognition processes.

  14. Identification of amino-acid residues in the V protein of peste des petits ruminants essential for interference and suppression of STAT-mediated interferon signaling

    SciTech Connect

    Ma, Xusheng; Yang, Xing; Nian, Xiaofeng; Zhang, Zhidong; Dou, Yongxi; Zhang, Xuehu; Luo, Xuenong; Su, Junhong; Zhu, Qiyun; Cai, Xuepeng

    2015-09-15

    Peste des petits ruminants virus (PPRV) causes a fatal disease in small ruminants. V protein of PPRV plays a pivotal role in interfering with host innate immunity by blocking IFNs signaling through interacting with STAT1 and STAT2. In the present study, the results demonstrated that PPRV V protein blocks IFN actions in a dose dependent manner and restrains the translocation of STAT1/2 proteins. We speculate that the translocation inhibition might be caused by the interfering of the downstream of STAT protein. Mutagenesis defines that Cys cluster and Trp motif of PPRV V protein are essential for STAT-mediated IFN signaling. These findings give a new sight for the further studies to understand the delicate mechanism of PPRV to escape the IFN signaling. - Highlights: • PPRV V protein inhibits type I IFN production and blocks its activation. • PPRV V protein negatively regulates activation of ISRE and GAS promoter. • PPRV V protein inhibits nuclear translocation of STAT protein by non-degradation. • PNT and VCT domain of PPRV V protein inhibit IFN transduction. • PPRV V protein binds with STAT protein via some conserved motifs.

  15. Pesticide residues in essential oils: evaluation of a database.

    PubMed

    Klier, B; Knödler, M; Peschke, J; Riegert, U; Steinhoff, B

    2015-01-01

    In the context of a revision of the European Pharmacopoeia (Ph. Eur.) general monograph Essential oils (2098), the need to include a test for pesticides is being discussed. According to published literature, some oils, mainly those produced by cold pressing (e.g. citrus oils), can contain relevant amounts of pesticide residues, whereas distilled oils showed positive findings in only a few cases. Recent evaluation of a database containing 127 517 sets of data compiled over 8 years, showed positive results in 1 150 cases (0.90 per cent), and the limits of Ph. Eur. general chapter 2.8.13 Pesticide residues or Regulation (EC) 396/2005, both applicable to herbal drugs, were exceeded in 392 cases (0.31 per cent, equivalent to 34.1 per cent of the positive results), particularly in cases of oils produced by cold pressing. From these results, it can be concluded that a general test on pesticides in the Ph. Eur. general monograph on essential oils is not required for most oils used in medicinal products. Therefore, it is proposed to limit the testing of essential oils for pesticide residues to those cases where potential residues are more of a concern, either due to the type of production process or to those processes where pesticides are actively used during cultivation of the plant (e.g. as documented according to Good Agricultural and Collection Practice (GACP)). Furthermore, in order to assess any potential risk, an approach using the Acceptable Daily Intake (ADI) can be made.

  16. Uric acid in childhood essential hypertension.

    PubMed

    Prebis, J W; Gruskin, A B; Polinsky, M S; Baluarte, H J

    1981-05-01

    Serum uric acid concentrations and the fractional excretion of uric acid were determined in 31 children from 3 1/2 to 18 years of age with essential hypertension. While on an unrestricted sodium intake, elevated serum values of uric acid were found in 13 of 31 (42%) of the children. After ingesting a low-sodium diet (200 mg/day) for three days, mean serum uric acid values increased by 0.7 mg/dl (P less than 0.001). There was a significant inverse correlation between the serum uric acid concentrations and fractional excretion of uric acid during the normal and low-sodium diet. This study indicates that the major factor leading to hyperuricemia in our hypertensive patients was a decrease in urate clearance. Insofar as hyperuricemia may represent a cardiovascular risk factor, this abnormality already exists in a significant fraction of hypertensive children and adolescents.

  17. Chemical modification of glycerinated stalks shows tyrosine residues essential for spasmoneme contraction of Vorticella sp.

    PubMed

    Fang, Jie; Zhang, Bei; Chen, Ning; Asai, Hiroshi

    2004-05-01

    Chemical modification of glycerinated stalks of Vorticella with TNM is used to investigate the role of tyrosine residues in the Ca(2+)-induced contraction of the spasmoneme. Tetranitromethane (TNM) is often employed as a specific reagent for the nitration of tyrosine residues in a protein at neutral and slightly alkaline pHs although TNM can also oxidize cysteine residues in the acidic and neutral pH range. Prior incubation with Ca(2+) of stalks to be treated with TNM can protect the spasmoneme from irreversible denaturation. On the other hand, TNM treatment in the absence of free Ca(2+) causes an irreversible denaturation of the spasmoneme. It was revealed by us that an isolated Ca(2+)-binding protein called spasmin could not bind with Ca(2+) after TNM treatment, even if the treatment was performed in the presence of Ca(2+). In an additional experiment, we confirmed that the chemical modification of cysteine residues in the spasmoneme with N-7-dimethyl-amino-4methyl- coumarinyl- maleimide (DACM) has no effect on the contractibility. These results suggest that tyrosine residues in spasmin are essential for spasmoneme contraction and are protected from TNM in the presence of Ca(2+) when spasmin binds with its receptor protein in the spasmoneme.

  18. Fish oil, essential fatty acids, and hypertension.

    PubMed

    Lee, R M

    1994-08-01

    A proper balance between the n-3 and n-6 series of essential fatty acids (EFAs) is essential for homeostasis and normal growth in humans. Dietary supplement with fish oil and related n-3 EFAs has been used to study their antihypertensive property in animals and humans with borderline and essential hypertension. In the animal models, chronic treatment of young animals generally only attenuated the development of hypertension. In animals with hypercholesterolemia, n-3 EFA supplement increased the incidence of atherosclerosis. In humans, chronic treatment with fish oil only produced a small reduction in blood pressure. The concerns are that the high dose of fish oil may interfere with the control of blood glucose in diabetic patients, and may cause prolonged bleeding in surgical patients. Studies on the animal models of hypertension showed that n-6 EFAs are more effective than n-3 EFAs in lowering and normalizing the blood pressure of these animals, probably through the production of tissue prostaglandins, which favour vasodilation. The antihypertensive effect of the n-6 EFAs in humans is not well known, because there are only a few studies, usually involving a very small number of patients. A possible side effects of n-6 EFAs for concern is that they might stimulate tumour development. A careful examination of these risk factors is needed before any recommendation can be made concerning the use of EFAs for the control of hypertension for humans.

  19. Modification of bovine heart succinate dehydrogenase with ethoxyformic anhydride and rose bengal: evidence for essential histidyl residues protectable by substrates.

    PubMed

    Hederstedt, L; Hatefi, Y

    1986-06-01

    Purified and membrane-bound succinate dehydrogenase (SDH) from bovine heart mitochondria was inhibited by the histidine-modifying reagents ethoxyformic anhydride (EFA) and Rose Bengal in the presence of light. Succinate and competitive inhibitors protected against inhibition, and decreased the number of histidyl residues modified by EFA. The essential residue modified by EFA was not the essential thiol of SDH, but modification of the essential thiol abolished the protective effect of malonate against inhibition of SDH by EFA. The EFA inhibition was reversed by hydroxylamine nearly completely when the inhibition was less than or equal to 35%, and only partially when the inhibition was more extensive. The uv spectrum of EFA-modified SDH before and after hydroxylamine treatment suggested that extensive inhibition of SDH with EFA may result in ethoxyformylation at both imidazole nitrogens of histidyl residues. Such a modification is not reversed by hydroxylamine. Succinate dehydrogenases and fumarate reductases from several different sources have similar compositions, and the two enzymes from Escherichia coli have considerable homology in the amino acid composition of their respective flavoprotein and iron-sulfur protein subunits. In the former, there is a short stretch containing conserved histidine, cysteine, and arginine residues. These residues, if also conserved in the bovine enzyme, may be the essential active site residues suggested by this work (histidine) and previously (cysteine, arginine).

  20. The essentiality of arachidonic acid and docosahexaenoic acid

    PubMed Central

    Le, Hau D.; Meisel, Jonathan A.; de Meijer, Vincent E.; Gura, Kathleen M.; Puder, Mark

    2012-01-01

    Objective The purpose of this review is to correlate the clinical finding that patients receiving parenteral nutrition with a fish oil-based lipid emulsion do not develop essential fatty acid deficiency (EFAD) with an experimental murine model, thus showing that arachidonic acid (AA) and docosahexaenoic acid (DHA) are likely to be the essential fatty acids. Background Conventional belief is that linoleic acid (LA, omega-6) and alpha-linolenic acid (ALA, omega-3) are the essential fatty acids (EFAs). We have shown that a fish oil-based lipid emulsion containing AA (omega-6) and docosahexaenoic acid (DHA, omega-3) and insignificant quantities of LA and ALA is efficacious in the treatment of parenteral nutrition-associated liver disease (PNALD), a major cause of liver-related morbidity and mortality. The prospect of using a fish oil-based lipid emulsion as monotherapy has raised concerns of EFAD development, hindering its adoption into clinical practice. Design Data from patients in our institution who received PN with a fish oil-based lipid emulsion was reviewed for clinical and biochemical evidence of EFAD, defined as an elevated triene-tetraene ratio (Mead acid/AA >0.2). We also investigated the minimum amount of fish oil required to prevent EFAD in a murine model and determined whether DHA and AA alone can prevent EFAD. Results No patients receiving PN with a fish oil-based lipid emulsion in our institution have developed biochemical or clinical evidence of EFAD such as an elevated triene-tetraene ratio, growth retardation or dermatitis. This observation parallels our previously published animal studies, which demonstrated prevention of EFAD when thirteen percent of total calories were from fish oil. Moreover, current work in our laboratory shows that AA and DHA provision alone is sufficient to prevent biochemical and physiologic evidence of EFAD in a murine model. Conclusions When dosed appropriately, fish oil-based lipid emulsions contain sufficient EFAs to

  1. Improving the acidic stability of a methyl parathion hydrolase by changing basic residues to acidic residues.

    PubMed

    Huang, Lu; Wang, Ping; Tian, Jian; Jiang, Huachen; Wu, Ningfeng; Yang, Peilong; Yao, Bin; Fan, Yunliu

    2012-06-01

    The acidic stability of a methyl parathion hydrolase (Ochr-MPH) was improved by selectively changing basic amino acids to acidic ones. Mutation sites were selected based on the position-specific amino acid replacement probabilities (more than or equal to 0.2) and the entropy of each site (more than or equal to 0.8). Three mutants (K208E, K277D, and K208E/K277D) were more stable than the wild-type (WT). Their half-lives at pH 5.0 were 64, 68, 65 min, respectively, whereas that of WT was 39 min. The acidic stability of proteins may therefore be improved by changing selected basic amino acid residues to acidic ones.

  2. Essential Amino Acids of the Hantaan Virus N Protein in Its Interaction with RNA

    PubMed Central

    Severson, William; Xu, Xiaolin; Kuhn, Michaela; Senutovitch, Nina; Thokala, Mercy; Ferron, François; Longhi, Sonia; Canard, Bruno; Jonsson, Colleen B.

    2005-01-01

    The nucleocapsid (N) protein of hantavirus encapsidates viral genomic and antigenomic RNAs. Previously, deletion mapping identified a central, conserved region (amino acids 175 to 217) within the Hantaan virus (HTNV) N protein that interacts with a high affinity with these viral RNAs (vRNAs). To further define the boundaries of the RNA binding domain (RBD), several peptides were synthesized and examined for the ability to bind full-length S-segment vRNA. Peptide 195-217 retained 94% of the vRNA bound by the HTNV N protein, while peptides 175-186 and 205-217 bound only 1% of the vRNA. To further explore which residues were essential for binding vRNA, we performed a comprehensive mutational analysis of the amino acids in the RBD. Single and double Ala substitutions were constructed for 18 amino acids from amino acids 175 to 217 in the full-length N protein. In addition, Ala substitutions were made for the three R residues in peptide 185-217. An analysis of protein-RNA interactions by electrophoretic mobility shift assays implicated E192, Y206, and S217 as important for binding. Chemical modification experiments showed that lysine residues, but not arginine or cysteine residues, contribute to RNA binding, which agreed with bioinformatic predictions. Overall, these data implicate lysine residues dispersed from amino acids 175 to 429 of the protein and three amino acids located in the RBD as essential for RNA binding. PMID:16014963

  3. 40 CFR 180.289 - Methanearsonic acid; tolerances for residues.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... residues. 180.289 Section 180.289 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) PESTICIDE PROGRAMS TOLERANCES AND EXEMPTIONS FOR PESTICIDE CHEMICAL RESIDUES IN FOOD Specific Tolerances § 180.289 Methanearsonic acid; tolerances for residues. (a) General. Tolerances are established...

  4. 40 CFR 180.311 - Cacodylic acid; tolerances for residues.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... residues. 180.311 Section 180.311 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) PESTICIDE PROGRAMS TOLERANCES AND EXEMPTIONS FOR PESTICIDE CHEMICAL RESIDUES IN FOOD Specific Tolerances § 180.311 Cacodylic acid; tolerances for residues. (a) General. Tolerances are established for...

  5. 40 CFR 180.289 - Methanearsonic acid; tolerances for residues.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 25 2012-07-01 2012-07-01 false Methanearsonic acid; tolerances for...) PESTICIDE PROGRAMS TOLERANCES AND EXEMPTIONS FOR PESTICIDE CHEMICAL RESIDUES IN FOOD Specific Tolerances § 180.289 Methanearsonic acid; tolerances for residues. (a) General. Tolerances are established...

  6. 40 CFR 180.289 - Methanearsonic acid; tolerances for residues.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 24 2014-07-01 2014-07-01 false Methanearsonic acid; tolerances for...) PESTICIDE PROGRAMS TOLERANCES AND EXEMPTIONS FOR PESTICIDE CHEMICAL RESIDUES IN FOOD Specific Tolerances § 180.289 Methanearsonic acid; tolerances for residues. (a) General. Tolerances are established...

  7. 40 CFR 180.289 - Methanearsonic acid; tolerances for residues.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 24 2011-07-01 2011-07-01 false Methanearsonic acid; tolerances for...) PESTICIDE PROGRAMS TOLERANCES AND EXEMPTIONS FOR PESTICIDE CHEMICAL RESIDUES IN FOOD Specific Tolerances § 180.289 Methanearsonic acid; tolerances for residues. (a) General. Tolerances are established...

  8. 40 CFR 180.289 - Methanearsonic acid; tolerances for residues.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 25 2013-07-01 2013-07-01 false Methanearsonic acid; tolerances for...) PESTICIDE PROGRAMS TOLERANCES AND EXEMPTIONS FOR PESTICIDE CHEMICAL RESIDUES IN FOOD Specific Tolerances § 180.289 Methanearsonic acid; tolerances for residues. (a) General. Tolerances are established...

  9. Recovery of mercury from acid waste residues

    DOEpatents

    Greenhalgh, Wilbur O.

    1989-12-05

    Mercury can be recovered from nitric acid-containing fluids by reacting the fluid with aluminum metal to produce mercury metal, and then quenching the reactivity of the nitric acid prior to nitration of the mercury metal.

  10. Recovery of mercury from acid waste residues

    DOEpatents

    Greenhalgh, W.O.

    1987-02-27

    Mercury can be recovered from nitric acid-containing fluids by reacting the fluid with aluminum metal to produce mercury metal, and thence quenching the reactivity of the nitric acid prior to nitration of the mercury metal. 1 fig.

  11. Recovery of mercury from acid waste residues

    DOEpatents

    Greenhalgh, Wilbur O.

    1989-01-01

    Mercury can be recovered from nitric acid-containing fluids by reacting the fluid with aluminum metal to produce mercury metal, and then quenching the reactivity of the nitric acid prior to nitration of the mercury metal.

  12. Child Stunting is Associated with Low Circulating Essential Amino Acids

    PubMed Central

    Semba, Richard D.; Shardell, Michelle; Sakr Ashour, Fayrouz A.; Moaddel, Ruin; Trehan, Indi; Maleta, Kenneth M.; Ordiz, M. Isabel; Kraemer, Klaus; Khadeer, Mohammed A.; Ferrucci, Luigi; Manary, Mark J.

    2016-01-01

    Background Stunting affects about one-quarter of children under five worldwide. The pathogenesis of stunting is poorly understood. Nutritional interventions have had only modest effects in reducing stunting. We hypothesized that insufficiency in essential amino acids may be limiting the linear growth of children. Methods We used a targeted metabolomics approach to measure serum amino acids, glycerophospholipids, sphingolipids, and other metabolites using liquid chromatography-tandem mass spectrometry in 313 children, aged 12–59 months, from rural Malawi. Children underwent anthropometry. Findings Sixty-two percent of the children were stunted. Children with stunting had lower serum concentrations of all nine essential amino acids (tryptophan, isoleucine, leucine, valine, methionine, threonine, histidine, phenylalanine, lysine) compared with nonstunted children (p < 0.01). In addition, stunted children had significantly lower serum concentrations of conditionally essential amino acids (arginine, glycine, glutamine), non-essential amino acids (asparagine, glutamate, serine), and six different sphingolipids compared with nonstunted children. Stunting was also associated with alterations in serum glycerophospholipid concentrations. Interpretation Our findings support the idea that children with a high risk of stunting may not be receiving an adequate dietary intake of essential amino acids and choline, an essential nutrient for the synthesis of sphingolipids and glycerophospholipids. PMID:27211567

  13. 40 CFR 180.180 - Orthoarsenic acid; tolerance for residues.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 23 2010-07-01 2010-07-01 false Orthoarsenic acid; tolerance for residues. 180.180 Section 180.180 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) PESTICIDE PROGRAMS TOLERANCES AND EXEMPTIONS FOR PESTICIDE CHEMICAL RESIDUES IN FOOD Specific...

  14. Fatty Acid Structure and Degradation Analysis in Fingerprint Residues.

    PubMed

    Pleik, Stefanie; Spengler, Bernhard; Schäfer, Thomas; Urbach, Dieter; Luhn, Steven; Kirsch, Dieter

    2016-09-01

    GC-MS investigations were carried out to elucidate the aging behavior of unsaturated fatty acids in fingerprint residues and to identify their degradation products in aged samples. For this purpose, a new sample preparation technique for fingerprint residues was developed that allows producing N-methyl-N-trimethylsilyl-trifluoroacetamide (MSTFA) derivatives of the analyzed unsaturated fatty acids and their degradation products. MSTFA derivatization catalyzed by iodotrimethylsilane enables the reliable identification of aldehydes and oxoacids as characteristic MSTFA derivatives in GCMS. The obtained results elucidate the degradation pathway of unsaturated fatty acids. Our study of aged fingerprint residues reveals that decanal is the main degradation product of the observed unsaturated fatty acids. Furthermore, oxoacids with different chain lengths are detected as specific degradation products of the unsaturated fatty acids. The detection of the degradation products and their chain length is a simple and effective method to determine the double bond position in unsaturated compounds. We can show that the hexadecenoic and octadecenoic acids found in fingerprint residues are not the pervasive fatty acids Δ9-hexadecenoic (palmitoleic acid) and Δ9-octadecenoic (oleic acid) acid but Δ6-hexadecenoic acid (sapienic acid) and Δ8-octadecenoic acid. The present study focuses on the structure identification of human sebum-specific unsaturated fatty acids in fingerprint residues based on the identification of their degradation products. These results are discussed for further investigations and method developments for age determination of fingerprints, which is still a tremendous challenge because of several factors affecting the aging behavior of individual compounds in fingerprints. Graphical Abstract ᅟ.

  15. Fatty Acid Structure and Degradation Analysis in Fingerprint Residues

    NASA Astrophysics Data System (ADS)

    Pleik, Stefanie; Spengler, Bernhard; Schäfer, Thomas; Urbach, Dieter; Luhn, Steven; Kirsch, Dieter

    2016-09-01

    GC-MS investigations were carried out to elucidate the aging behavior of unsaturated fatty acids in fingerprint residues and to identify their degradation products in aged samples. For this purpose, a new sample preparation technique for fingerprint residues was developed that allows producing N-methyl- N-trimethylsilyl-trifluoroacetamide (MSTFA) derivatives of the analyzed unsaturated fatty acids and their degradation products. MSTFA derivatization catalyzed by iodotrimethylsilane enables the reliable identification of aldehydes and oxoacids as characteristic MSTFA derivatives in GCMS. The obtained results elucidate the degradation pathway of unsaturated fatty acids. Our study of aged fingerprint residues reveals that decanal is the main degradation product of the observed unsaturated fatty acids. Furthermore, oxoacids with different chain lengths are detected as specific degradation products of the unsaturated fatty acids. The detection of the degradation products and their chain length is a simple and effective method to determine the double bond position in unsaturated compounds. We can show that the hexadecenoic and octadecenoic acids found in fingerprint residues are not the pervasive fatty acids Δ9-hexadecenoic (palmitoleic acid) and Δ9-octadecenoic (oleic acid) acid but Δ6-hexadecenoic acid (sapienic acid) and Δ8-octadecenoic acid. The present study focuses on the structure identification of human sebum-specific unsaturated fatty acids in fingerprint residues based on the identification of their degradation products. These results are discussed for further investigations and method developments for age determination of fingerprints, which is still a tremendous challenge because of several factors affecting the aging behavior of individual compounds in fingerprints.

  16. 40 CFR 180.550 - Arsanilic acid [(4-aminophenyl) arsonic acid]; tolerances for residues.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... for residues of the plant growth regulator arsanilic acid , in or on the following food commodities in...) PESTICIDE PROGRAMS TOLERANCES AND EXEMPTIONS FOR PESTICIDE CHEMICAL RESIDUES IN FOOD Specific...

  17. 40 CFR 180.550 - Arsanilic acid [(4-aminophenyl) arsonic acid]; tolerances for residues.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... for residues of the plant growth regulator arsanilic acid , in or on the following food commodities in...) PESTICIDE PROGRAMS TOLERANCES AND EXEMPTIONS FOR PESTICIDE CHEMICAL RESIDUES IN FOOD Specific...

  18. 40 CFR 180.550 - Arsanilic acid [(4-aminophenyl) arsonic acid]; tolerances for residues.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... for residues of the plant growth regulator arsanilic acid , in or on the following food commodities in...) PESTICIDE PROGRAMS TOLERANCES AND EXEMPTIONS FOR PESTICIDE CHEMICAL RESIDUES IN FOOD Specific...

  19. Current topics in the biotechnological production of essential amino acids, functional amino acids, and dipeptides.

    PubMed

    Mitsuhashi, Satoshi

    2014-04-01

    Amino acids play important roles in both human and animal nutrition and in the maintenance of health. Here, amino acids are classified into three groups: first, essential amino acids, which are essential to nutrition; second, functional amino acids, recently found to be important in the promotion of physiological functions; and third, dipeptides, which are used to resolve problematic features of specific free amino acids, such as their instability or insolubility. This review focusses on recent researches concerning the microbial production of essential amino acids (lysine and methionine), functional amino acids (histidine and ornithine), and a dipeptide (L-alanyl-L-glutamine).

  20. Microscopic residues of bone from dissolving human remains in acids.

    PubMed

    Vermeij, Erwin; Zoon, Peter; van Wijk, Mayonne; Gerretsen, Reza

    2015-05-01

    Dissolving bodies is a current method of disposing of human remains and has been practiced throughout the years. During the last decade in the Netherlands, two cases have emerged in which human remains were treated with acid. In the first case, the remains of a cremated body were treated with hydrofluoric acid. In the second case, two complete bodies were dissolved in a mixture of hydrochloric and sulfuric acid. In both cases, a great variety of evidence was collected at the scene of crime, part of which was embedded in resin, polished, and investigated using SEM/EDX. Apart from macroscopic findings like residual bone and artificial teeth, in both cases, distinct microscopic residues of bone were found as follows: (partly) digested bone, thin-walled structures, and recrystallized calcium phosphate. Although some may believe it is possible to dissolve a body in acid completely, at least some of these microscopic residues will always be found.

  1. Acid transformation of bauxite residue: Conversion of its alkaline characteristics.

    PubMed

    Kong, Xiangfeng; Li, Meng; Xue, Shengguo; Hartley, William; Chen, Chengrong; Wu, Chuan; Li, Xiaofei; Li, Yiwei

    2017-02-15

    Bauxite residue (BR) is a highly alkaline solid hazardous waste produced from bauxite processing for alumina production. Alkaline transformation appears to reduce the environmental risk of bauxite residue disposal areas (BRDAs) whilst potentially providing opportunities for the sustainable reuse and on-going management of BR. Mineral acids, a novel citric acid and a hybrid combination of acid-gypsum treatments were investigated for their potential to reduce residue pH and total alkalinity and transform the alkaline mineral phase. XRD results revealed that with the exception of andradite, the primary alkaline solid phases of cancrinite, grossular and calcite were transformed into discriminative products based on the transformation used. Supernatants separated from BR and transformed bauxite residue (TBR) displayed distinct changes in soluble Na, Ca and Al, and a reduction in pH and total alkalinity. SEM images suggest that mineral acid transformations promote macro-aggregate formation, and the positive promotion of citric acid, confirming the removal or reduction in soluble and exchangeable Na. NEXAFS analysis of Na K-edge revealed that the chemical speciation of Na in TBRs was consistent with BR. Three acid treatments and gypsum combination had no effect on Na speciation, which affects the distribution of Na revealed by sodium STXM imaging.

  2. Electron microscopy of carbonaceous matter in Allende acid residues

    NASA Technical Reports Server (NTRS)

    Lumpkin, G. R.

    1982-01-01

    On the basis of characteristic diffuse ring diffraction patterns, much of the carbonaceous matter in a large suite of Allende acid residues has been identified as a variety of turbostratic carbon. Crystallites of this phase contain randomly stacked sp(2) hybridized carbon layers and diffraction patterns resemble those from carbon black and glassy carbon. Carbynes are probably absent, and are certainly restricted to less than 0.5% of these acid residues. The work of Ott et al. (1981) provides a basis for the possibility that turbostratic carbon is a carrier of noble gases, but an additional component - amorphous carbon - may be necessary to explain the high release temperatures of noble gases as well as the glassy character of many of the carbonaceous particles. Carbynes are considered to be questionable as important carriers of noble gases in the Allende acid residues.

  3. Child stunting is associated with low circulating essential amino acids

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Stunting affects about one-quarter of children under five worldwide. The pathogenesis of stunting is poorly understood. Nutritional interventions have had only modest effects in reducing stunting. We hypothesized that insufficiency in essential amino acids may be limiting the linear growth of childr...

  4. Dietary essentiality of "nutritionally non-essential amino acids" for animals and humans.

    PubMed

    Hou, Yongqing; Yin, Yulong; Wu, Guoyao

    2015-08-01

    Based on growth or nitrogen balance, amino acids (AA) had traditionally been classified as nutritionally essential (indispensable) or non-essential (dispensable) for animals and humans. Nutritionally essential AA (EAA) are defined as either those AA whose carbon skeletons cannot be synthesized de novo in animal cells or those that normally are insufficiently synthesized de novo by the animal organism relative to its needs for maintenance, growth, development, and health and which must be provided in the diet to meet requirements. In contrast, nutritionally non-essential AA (NEAA) are those AA which can be synthesized de novo in adequate amounts by the animal organism to meet requirements for maintenance, growth, development, and health and, therefore, need not be provided in the diet. Although EAA and NEAA had been described for over a century, there are no compelling data to substantiate the assumption that NEAA are synthesized sufficiently in animals and humans to meet the needs for maximal growth and optimal health. NEAA play important roles in regulating gene expression, cell signaling pathways, digestion and absorption of dietary nutrients, DNA and protein synthesis, proteolysis, metabolism of glucose and lipids, endocrine status, men and women fertility, acid-base balance, antioxidative responses, detoxification of xenobiotics and endogenous metabolites, neurotransmission, and immunity. Emerging evidence indicates dietary essentiality of "nutritionally non-essential amino acids" for animals and humans to achieve their full genetic potential for growth, development, reproduction, lactation, and resistance to metabolic and infectious diseases. This concept represents a new paradigm shift in protein nutrition to guide the feeding of mammals (including livestock), poultry, and fish.

  5. Functional analyses of carnivorous plant-specific amino acid residues in S-like ribonucleases.

    PubMed

    Arai, Naoki; Nishimura, Emi; Kikuchi, Yo; Ohyama, Takashi

    2015-09-11

    Unlike plants with no carnivory, carnivorous plants seem to use S-like ribonucleases (RNases) as an enzyme for carnivory. Carnivorous plant-specific conserved amino acid residues are present at four positions around the conserved active site (CAS). The roles of these conserved amino acid residues in the enzymatic function were explored in the current study by preparing five recombinant variants of DA-I, the S-like RNase of Drosera adelae. The kcat and kcat/Km values of the enzymes revealed that among the four variants with a single mutation, the serine to glycine mutation at position 111 most negatively influenced the enzymatic activity. The change in the bulkiness of the amino acid residue side-chain seemed to be the major cause of the above effect. Modeling of the three dimensional (3D) structures strongly suggested that the S to G mutation at 111 greatly altered the overall enzyme conformation. The conserved four amino acid residues are likely to function in keeping the two histidine residues, which are essential for the cleavage of RNA strands, and the CAS in the most functional enzymatic conformation.

  6. Effect of essential fatty acids on tumor cells.

    PubMed

    Ramesh, G; Das, U N; Koratkar, R; Padma, M; Sagar, P S

    1992-01-01

    An earlier study showed that essential fatty acids and their metabolites can kill tumor cells in vitro. This tumoricidal action can be correlated to an increase in generation of free radicals in the tumor cells. Evening primrose oil (EPO) is a rich source of linoleic acid and gamma-linolenic acid. We report that EPO can kill tumor cells both in vitro and in vivo. This tumoricidal action of EPO was associated with a threefold increase in superoxide generation. One of the factors that is capable of interfering with the cytotoxic action of fatty acids appears to be the protein content of the medium. Fatty acids can bind to protein and thus prevent their cytotoxic action.

  7. Essential fatty acids in health and chronic disease.

    PubMed

    Simopoulos, A P

    1999-09-01

    Human beings evolved consuming a diet that contained about equal amounts of n-3 and n-6 essential fatty acids. Over the past 100-150 y there has been an enormous increase in the consumption of n-6 fatty acids due to the increased intake of vegetable oils from corn, sunflower seeds, safflower seeds, cottonseed, and soybeans. Today, in Western diets, the ratio of n-6 to n-3 fatty acids ranges from approximately 20-30:1 instead of the traditional range of 1-2:1. Studies indicate that a high intake of n-6 fatty acids shifts the physiologic state to one that is prothrombotic and proaggregatory, characterized by increases in blood viscosity, vasospasm, and vasoconstriction and decreases in bleeding time. n-3 Fatty acids, however, have antiinflammatory, antithrombotic, antiarrhythmic, hypolipidemic, and vasodilatory properties. These beneficial effects of n-3 fatty acids have been shown in the secondary prevention of coronary heart disease, hypertension, type 2 diabetes, and, in some patients with renal disease, rheumatoid arthritis, ulcerative colitis, Crohn disease, and chronic obstructive pulmonary disease. Most of the studies were carried out with fish oils [eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA)]. However, alpha-linolenic acid, found in green leafy vegetables, flaxseed, rapeseed, and walnuts, desaturates and elongates in the human body to EPA and DHA and by itself may have beneficial effects in health and in the control of chronic diseases.

  8. Evidence that the amino acid residue Cys117 of chloroplastic monodehydroascorbate reductase is involved in its activity and structural stability.

    PubMed

    Li, Feng; Wu, Qing-Yun; Sun, Yan-Li; Ma, Na-Na; Wang, Xiao-Yun; Meng, Qing-Wei

    2010-04-01

    Monodehydroascorbate reductase (MDAR; EC 1.6.5.4) is crucial for AsA regeneration and essential for maintaining the reduced pool of AsA. And the amino acid residue C117 of chloroplastic MDAR is the conserved cysteine residue in MDAR isoforms. A series mutation of conserved amino acid residue cysteine117 (C117) was constructed to investigate its role in MDAR structural stability and activity. Our study revealed that mutation in this conserved residue could cause pronounced loss of activity and conformational changes. Spectroscopic experiments indicated that these mutations influenced transition from the molten globule intermediate to the native state in folding process. These results suggested that amino acid residue C117 played a relatively important role in keeping MDAR structural stability and activity.

  9. Pesticide and plasticizer residues in bergamot essential oils from Calabria (Italy).

    PubMed

    Di Bella, Giuseppa; Saitta, Marcello; La Pera, Lara; Alfa, Maria; Dugo, Giacomo

    2004-08-01

    Organophosphorus and organochlorine pesticides, phosphorated plasticizers, chloroparaffins and phthalate esters contamination in bergamot essential oils produced in Calabria in the crop years 1999-2000 was studied by HRGC in connection with detectors FPD, ECD, MS. Residues of dicofol and tetradifon were found in oils from both crop years. The mean dicofol concentration was 0.26 mg/l in samples from 1999 and 0.20 mg/l in those from 2000; the mean tetradifon content was 0.06 mg/l for both the crop years. Among plasticizers, residues of diisobutyl phthalate, di-n-butyl phthalate, and bis(2-ethylhexyl) phthalate were found in samples from crop years 1999 and 2000, the mean content were 1.22 and 1.23 mg/l, 1.51 and 1.65 mg/l, 1.38 and 1.42 mg/l respectively.

  10. Lactic Acid and Biosurfactants Production from Residual Cellulose Films.

    PubMed

    Portilla Rivera, Oscar Manuel; Arzate Martínez, Guillermo; Jarquín Enríquez, Lorenzo; Vázquez Landaverde, Pedro Alberto; Domínguez González, José Manuel

    2015-11-01

    The increasing amounts of residual cellulose films generated as wastes all over the world represent a big scale problem for the meat industry regarding to environmental and economic issues. The use of residual cellulose films as a feedstock of glucose-containing solutions by acid hydrolysis and further fermentation into lactic acid and biosurfactants was evaluated as a method to diminish and revalorize these wastes. Under a treatment consisting in sulfuric acid 6% (v/v); reaction time 2 h; solid liquid ratio 9 g of film/100 mL of acid solution, and temperature 130 °C, 35 g/L of glucose and 49% of solubilized film was obtained. From five lactic acid strains, Lactobacillus plantarum was the most suitable for metabolizing the glucose generated. The process was scaled up under optimized conditions in a 2-L bioreactor, producing 3.4 g/L of biomass, 18 g/L of lactic acid, and 15 units of surface tension reduction of a buffer phosphate solution. Around 50% of the cellulose was degraded by the treatment applied, and the liqueurs generated were useful for an efficient production of lactic acid and biosurfactants using L. plantarum. Lactobacillus bacteria can efficiently utilize glucose from cellulose films hydrolysis without the need of clarification of the liqueurs.

  11. Covalent modification of a highly reactive and essential lysine residue of ribulose-1,5-bisphosphate carboxylase/oxygenase activase.

    PubMed

    Salvucci, M E

    1993-10-01

    Chemical modification of ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) activase with water-soluble N-hydroxysuccinimide esters was used to identify a reactive lysyl residue that is essential for activity. Incubation of Rubisco activase with sulfosuccinimidyl-7-amino-4-methylcoumarin-3-acetate (AMCA-sulfo-NHS) or sulfosuccinimidyl-acetate (sulfo-NHS-acetate) caused progressive inactivation of ATPase activity and concomitant loss of the ability to activate Rubisco. AMCA-sulfo-NHS was the more potent inactivator of Rubisco activase, exhibiting a second-order rate constant for inactivation of 239 M-1 s-1 compared to 21 M-1 s-1 for sulfo-NHS-acetate. Inactivation of enzyme activity by AMCA-sulfo-NHS correlated with the incorporation of 1.9 mol of AMCA per mol of 42-kD Rubisco activase monomer. ADP, a competitive inhibitor of Rubisco activase, afforded considerable protection against inactivation of Rubisco activase and decreased the amount of AMCA incorporated into the Rubisco activase monomer. Sequence analysis of the major labeled peptide from AMCA-sulfo-NHS-modified enzyme showed that the primary site of modification was lysine-247 (K247) in the tetrapeptide methionine-glutamic acid-lysine-phenylalanine. Upon complete inactivation of ATPase activity, modification of K247 accounted for 1 mol of AMCA incorporated per mol of Rubisco activase monomer. Photoaffinity labeling of AMCA-sulfo-NHS- and sulfo-NHS-acetate-modified Rubisco activase with ATP analogs derivatized on either the adenine base or on the gamma-phosphate showed that K247 is not essential for the binding of adenine nucleotides per se. Instead, the data indicated that the essentiality of K247 is probably due to an involvement of this highly reactive, species-invariant residue in an obligatory interaction that occurs between the protein and the nucleotide phosphate during catalysis.

  12. Serine residues in the LAT adaptor are essential for TCR-dependent signal transduction.

    PubMed

    Martínez-Florensa, Mario; García-Blesa, Antonio; Yélamos, José; Muñoz-Suano, Alba; Domínguez-Villar, Margarita; Valdor, Rut; Alonso, Antonio; García-Cózar, Francisco; Aparicio, Pedro; Malissen, Bernard; Aguado, Enrique

    2011-01-01

    The adaptor protein LAT has a prominent role in the transduction of intracellular signals elicited by the TCR/CD3 complex. Upon TCR engagement, LAT becomes tyrosine-phosphorylated and thereby, recruits to the membrane several proteins implicated in the activation of downstream signaling pathways. However, little is known about the role of other conserved motifs present in the LAT sequence. Here, we report that the adaptor LAT contains several conserved serine-based motifs, which are essential for proper signal transduction through the TCR. Mutation of these serine motifs in the human T cell line Jurkat prevents proper calcium influx, MAPK activation, and IL-2 production in response to TCR/CD3 stimulation. Moreover, this mutant form of LAT has a reduced ability to bind to PLC-γ1 and SLP-76, although phosphorylation of tyrosine residues 132, 171, and 191 is not decreased, raising a possible role for the serine-based motifs of LAT for the binding of important partners. The functional role of LAT serine-based motifs in signal transduction could be mediated by an effect on tyrosine phosphorylation, as their mutation significantly diminishes the phosphorylation of tyrosine residue 226. In addition, these serine motifs seem to have a regulatory role, given that upon their mutation, ZAP-70 shows enhanced phosphorylation. Therefore, the LAT serine-based motifs likely regulate signaling pathways that are essential for T cell physiology.

  13. Four residues of propeptide are essential for precursor folding of nattokinase.

    PubMed

    Jia, Yan; Cao, Xinhua; Deng, Yu; Bao, Wei; Tang, Changyan; Ding, Hanjing; Zheng, Zhongliang; Zou, Guolin

    2014-11-01

    Subtilisin propeptide functions as an intramolecular chaperone that guides precursor folding. Nattokinase, a member of subtilisin family, is synthesized as a precursor consisting of a signal peptide, a propeptide, and a subtilisin domain, and the mechanism of its folding remains to be understood. In this study, the essential residues of nattokinase propeptide which contribute to precursor folding were determined. Deletion analysis showed that the conserved regions in propeptide were important for precursor folding. Single-site and multi-site mutagenesis studies confirmed the role of Tyr10, Gly13, Gly34, and Gly35. During stage (i) and (ii) of precursor folding, Tyr10 and Gly13 would form the part of interface with subtilisin domain. While Gly34 and Gly35 connected with an α-helix that would stabilize the structure of propeptide. The quadruple Ala mutation, Y10A/G13A/G34A/G35A, resulted in a loss of the chaperone function for the propeptide. This work showed the essential residues of propeptide for precursor folding via secondary structure and kinetic parameter analyses.

  14. Structure-function studies of nerve growth factor: functional importance of highly conserved amino acid residues.

    PubMed Central

    Ibáñez, C F; Hallböök, F; Ebendal, T; Persson, H

    1990-01-01

    Selected amino acid residues in chicken nerve growth factor (NGF) were replaced by site-directed mutagenesis. Mutated NGF sequences were transiently expressed in COS cells and the yield of NGF protein in conditioned medium was quantified by Western blotting. Binding of each mutant to NGF receptors on PC12 cells was evaluated in a competition assay. The biological activity was determined by measuring stimulation of neurite outgrowth from chick sympathetic ganglia. The residues homologous to the proposed receptor binding site of insulin (Ser18, Met19, Val21, Asp23) were substituted by Ala. Replacement of Ser18, Met19 and Asp23 did not affect NGF activity. Modification of Val21 notably reduced both receptor binding and biological activity, suggesting that this residue is important to retain a fully active NGF. The highly conserved Tyr51 and Arg99 were converted into Phe and Lys respectively, without changing the biological properties of the molecule. However, binding and biological activity were greatly impaired after the simultaneous replacement of both Arg99 and Arg102 by Gly. The three conserved Trp residues at positions 20, 75 and 98 were substituted by Phe. The Trp mutated proteins retained 15-60% of receptor binding and 40-80% of biological activity, indicating that the Trp residues are not essential for NGF activity. However, replacement of Trp20 significantly reduced the amount of NGF in the medium, suggesting that this residue may be important for protein stability. Images Fig. 4. PMID:2328722

  15. Essential fatty acid requirement of juvenile red drum (Sciaenops ocellatus).

    PubMed

    Lochmann, R T; Gatlin, D M

    1993-10-01

    Feeding experiments and laboratory analyses were conducted to establish the essential fatty acid (EFA) requirement of red drum (Sciaenops ocellatus). Juvenile red drum were maintained in aquaria containing brackish water (5 ± 2‰ total dissolved solids) for two 6-week experiments. Semipurified diets contained a total of 70% lipid consisting of different combinations of tristearin [predominantly 18:0] and the following fatty acid ethyl esters: oleate, linoleate, linolenate, and a mixture of highly unsaturated fatty acids (HUFA) containing approximately 60% eicosapentaenoate plus docosahexaenoate. EFA-deficient diets (containing only tristearin or oleate) rapidly reduced fish growth and feed efficiency, and increased mortality. Fin erosion and a "shock syndrome" also occurred in association with EFA deficiency. Of the diets containing fatty acid ethyl esters, those with 0.5-1% (n-3) HUFA (0.3-0.6% eicosapentaenoate plus docosahexaenoate) promoted the best growth, survival, and feed efficiency; however, the control diet containing 7% menhaden fish oil provided the best performance. Excess (n-3) HUFA suppressed fish weight gain; suppression became evident at 1.5% (n-3) HUFA, and was pronounced at 2.5%. Fatty acid compositions of whole-body, muscle and liver tissues from red drum fed the various diets generally reflected dietary fatty acids, but modifications of these patterns also were evident. Levels of saturated fatty acids appeared to be regulated independent of diet. In fish fed EFA-deficient diets (containing only tristearin or oleate), monoenes increased and (n-3) HUFA were preferentially conserved in polar lipid fractions. Eicosatrienoic acid [20:3(n-9)] was not elevated in EFA-deficient red drum, apparently due to their limited ability to transform fatty acids. Red drum exhibited some limited ability to elongate and desaturate linoleic acid [18:2(n-6)] and linolenic acid [18:3(n-3)]; however, metabolism of 18:3(n-3) did not generally result in increased

  16. Methodology for detecting residual phosphoric acid in polybenzoxazole fibers.

    PubMed

    Park, Eun Su; Sieber, John; Guttman, Charles; Rice, Kirk; Flynn, Kathleen; Watson, Stephanie; Holmes, Gale

    2009-12-01

    Because of the premature failure of in-service soft-body armor containing the ballistic fiber poly[(benzo-[1,2-d:5,4-d']-benzoxazole-2,6-diyl)-1,4-phenylene] (PBO), the Office of Law Enforcement Standards (OLES) at the National Institute of Standards and Technology (NIST) initiated a research program to investigate the reasons for this failure and to develop testing methodologies and protocols to ensure that these types of failures do not reoccur. In a report that focused on the stability of the benzoxazole ring that is characteristic of PBO fibers, Holmes, G. A.; Rice, K.; Snyder, C. R. J. Mater. Sci. 2006, 41, 4105-4116, showed that the benzoxazole ring was susceptible to hydrolytic degradation under acid conditions. Because of the processing conditions for the fibers, it is suspected by many researchers that residual phosphoric acid may cause degradation of the benzoxazole ring resulting in a reduction of ballistic performance. Prior to this work, no definitive data have indicated the presence of phosphoric acid since the residual phosphorus is not easily extracted and the processed fibers are known to incorporate phosphorus containing processing aids. Methods to efficiently extract phosphorus from PBO are described in this article. Further, characterization determined that the majority of the extractable phosphorus in PBO was attributed to the octyldecyl phosphate processing aid with some phosphoric acid being detected. Analysis by matrix assisted laser desorption ionization of model PBO oligomers indicates that the nonextractable phosphorus is attached to the PBO polymer chain as a monoaryl phosphate ester. The response of model aryl phosphates to NaOH exposure indicates that monoaryl phosphate ester is stable to NaOH washes used in the manufacturing process to neutralize the phosphoric acid reaction medium and to extract residual phosphorus impurities.

  17. Polylactic Acid-Lemongrass Essential Oil Nanocapsules with Antimicrobial Properties.

    PubMed

    Liakos, Ioannis L; Grumezescu, Alexandru Mihai; Holban, Alina Maria; Florin, Iordache; D'Autilia, Francesca; Carzino, Riccardo; Bianchini, Paolo; Athanassiou, Athanassia

    2016-07-07

    Polylactic acid was combined with lemongrass essential oil (EO) to produce functional nanocapsules (NCs). The obtained polylactic acid nanoparticles showed antimicrobial activity both with and without the presence of lemongrass oil; however, the presence of EO improved the activity of the NCs. The presence of lemongrass assisted the formation of well-separated NCs and also provided enhanced antimicrobial properties, since lemongrass is known for its antimicrobial character. Fluorescence microscopy was used to optically observe the nanoparticles and NCs and revealed the attachment of lemongrass oil with the polylactic acid NCs. Dynamic light scattering was used to determine their size. UV absorption was used to determine the exact amount of lemongrass oil found in the polylactic acid-lemongrass oil NCs, which was important for understanding the minimum inhibitory concentration for the antimicrobial experiments. A series of clinically important microbial species were used in the study and the obtained NCs proved to have very good antimicrobial properties against all tested strains. Such NCs can be used for the design of ecological strategies, based on natural alternatives, which may be efficient against severe infections, including those that involve resistant pathogens and biofilms or those with difficult to reach localization.

  18. 77 FR 65834 - Residues of Fatty Acids, Tall-Oil, Ethoxylated Propoxylated; Tolerance Exemption

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-10-31

    ... AGENCY 40 CFR Part 180 Residues of Fatty Acids, Tall-Oil, Ethoxylated Propoxylated; Tolerance Exemption... an exemption from the requirement of a tolerance for residues of fatty acids, tall-oil, ethoxylated... residues of fatty ] acids, tall-oil, ethoxylated propoxylated on food or feed commodities. DATES:...

  19. Conservation of cysteine residues in fungal histidine acid phytases.

    PubMed

    Mullaney, Edward J; Ullah, Abul H J

    2005-03-11

    Amino acid sequence analysis of fungal histidine acid phosphatases displaying phytase activity has revealed a conserved eight-cysteine motif. These conserved amino acids are not directly associated with catalytic function; rather they appear to be essential in the formation of disulfide bridges. Their role is seen as being similar to another eight-cysteine motif recently reported in the amino acid sequence of nearly 500 plant polypeptides. An additional disulfide bridge formed by two cysteines at the N-terminus of all the filamentous ascomycete phytases was also observed. Disulfide bridges are known to increase both stability and heat tolerance in proteins. It is therefore plausible that this extra disulfide bridge contributes to the higher stability found in phytase from some Aspergillus species. To engineer an enhanced phytase for the feed industry, it is imperative that the role of disulfide bridges be taken into cognizance and possibly be increased in number to further elevate stability in this enzyme.

  20. XPS and STEM studies of Allende acid insoluble residues

    NASA Technical Reports Server (NTRS)

    Housley, R. M.; Clarke, D. R.

    1980-01-01

    Data on Allende acid residues obtained both before and after etching with hot HNO3 are presented. X-ray photoelectron spectra show predominantly carbonaceous material plus Fe-deficient chromite in both cases. The HNO3 oxidizes the carbonaceous material to some extent. The small chromites in these residues have a wide range of compositions somewhat paralleling those observed in larger Allende chromites and in Murchison chromites, especially in the high Al contents; however, they are deficient in divalent cations, which makes them metastable and indicates that they must have formed at relatively low temperatures. It is suggested that they formed by precipitation of Cr(3+) and Fe(3+) from olivine at low temperature or during rapid cooling.

  1. Histidine, an essential amino acid for adult dogs.

    PubMed

    Cianciaruso, B; Jones, M R; Kopple, J D

    1981-06-01

    Twenty-seven adult female mongrel dogs were studied to evaluate whether histidine is an essential amino acid. Dogs were tube-fed isocaloric, isonitrogenous amino acid diets which provided either no histidine or 67 mg histidine/kg body weight/day. The histidine-free diet was fed to 10 dogs for 5.6 +/- 3.6 (SD) days and to six dogs for 59.2 +/- 6.0 days. In the short-term studies, there were no differences between the responses of the dogs fed the histidine-free and histidine-replete diets. In the long-term studies, dogs fed the histidine-free diet developed a significant decrease in plasma and muscle histidine, muscle carnosine, body weight, hematocrit and serum albumin. The dogs fed the histidine-free diet tried to avoid the feedings, and after several weeks, they often manifested reduced activity and listlessness. One dog died on the 72nd day. None of these manifestations occurred in the dogs fed the histidine-replete diet in the long-term studies. Plasma zinc and copper were not different in the two groups of dogs. However, at the end of the long-term studies, the dogs fed the histidine-free diet had significantly lower final whole blood zinc and copper concentrations as compared to the histidine-replete dogs. These findings indicate that histidine is an essential amino acid in adult female dogs. The syndrome associated with histidine-deficiency tends to develop slowly over many days to several weeks.

  2. Agrochemical characterization of vermicomposts produced from residues of Palo Santo (Bursera graveolens) essential oil extraction.

    PubMed

    Carrión-Paladines, Vinicio; Fries, Andreas; Gómez-Muñoz, Beatriz; García-Ruiz, Roberto

    2016-12-01

    Fruits of Palo Santo (Bursera graveolens) are used for essential oil extraction. The extraction process is very efficient, because up to 3% of the fresh fruits can be transformed into essential oil; however, a considerable amount of waste is concurrently produced (>97% of the fresh biomass). Recent developments in Ecuadorian policies to foster environmentally friendly agroforestry and industrial practices have led to widespread interest in reusing the waste. This study evaluated the application of four vermicomposts (VMs), which are produced from the waste of the Palo Santo fruit distillation in combination with other raw materials (kitchen leftovers, pig manure, goat manure, and King Grass), for agrochemical use and for carbon (C) and nitrogen (N) decomposition in two soils with different textures. The results showed that the vermicompost mixtures (VMM) were valuable for agricultural utilisation, because total N (min. 2.63%) was relatively high and the C/N ratio (max. 13.3), as well as the lignin (max. 3.8%) and polyphenol (max. 1.6%) contents were low. In addition, N availability increased for both soil types after the application of the VMM. In contrast, N became immobile during decomposition if the VM of the pure waste was added. This likely occurred because of the relatively low total N (1.16%) content and high C/N ratio (35.0). However, the comparatively low C decomposition of this VM type makes its application highly recommendable as a strategy to increase the levels of organic matter and C, as well as for soil reclamation. Overall, these results suggest that the residues of the Palo Santo essential oil extraction are a potential source for vermicompost production and sustainable agriculture.

  3. The Essentiality of Arachidonic Acid in Infant Development.

    PubMed

    Hadley, Kevin B; Ryan, Alan S; Forsyth, Stewart; Gautier, Sheila; Salem, Norman

    2016-04-12

    Arachidonic acid (ARA, 20:4n-6) is an n-6 polyunsaturated 20-carbon fatty acid formed by the biosynthesis from linoleic acid (LA, 18:2n-6). This review considers the essential role that ARA plays in infant development. ARA is always present in human milk at a relatively fixed level and is accumulated in tissues throughout the body where it serves several important functions. Without the provision of preformed ARA in human milk or infant formula the growing infant cannot maintain ARA levels from synthetic pathways alone that are sufficient to meet metabolic demand. During late infancy and early childhood the amount of dietary ARA provided by solid foods is low. ARA serves as a precursor to leukotrienes, prostaglandins, and thromboxanes, collectively known as eicosanoids which are important for immunity and immune response. There is strong evidence based on animal and human studies that ARA is critical for infant growth, brain development, and health. These studies also demonstrate the importance of balancing the amounts of ARA and DHA as too much DHA may suppress the benefits provided by ARA. Both ARA and DHA have been added to infant formulas and follow-on formulas for more than two decades. The amounts and ratios of ARA and DHA needed in infant formula are discussed based on an in depth review of the available scientific evidence.

  4. The Essentiality of Arachidonic Acid in Infant Development

    PubMed Central

    Hadley, Kevin B.; Ryan, Alan S.; Forsyth, Stewart; Gautier, Sheila; Salem, Norman

    2016-01-01

    Arachidonic acid (ARA, 20:4n-6) is an n-6 polyunsaturated 20-carbon fatty acid formed by the biosynthesis from linoleic acid (LA, 18:2n-6). This review considers the essential role that ARA plays in infant development. ARA is always present in human milk at a relatively fixed level and is accumulated in tissues throughout the body where it serves several important functions. Without the provision of preformed ARA in human milk or infant formula the growing infant cannot maintain ARA levels from synthetic pathways alone that are sufficient to meet metabolic demand. During late infancy and early childhood the amount of dietary ARA provided by solid foods is low. ARA serves as a precursor to leukotrienes, prostaglandins, and thromboxanes, collectively known as eicosanoids which are important for immunity and immune response. There is strong evidence based on animal and human studies that ARA is critical for infant growth, brain development, and health. These studies also demonstrate the importance of balancing the amounts of ARA and DHA as too much DHA may suppress the benefits provided by ARA. Both ARA and DHA have been added to infant formulas and follow-on formulas for more than two decades. The amounts and ratios of ARA and DHA needed in infant formula are discussed based on an in depth review of the available scientific evidence. PMID:27077882

  5. Residual and ovicidal efficacy of essential oil-based formulations in vitro against the donkey chewing louse Bovicola ocellatus.

    PubMed

    Sands, B; Ellse, L; Wall, R

    2016-03-01

    Essential oils have shown good experimental potential as novel veterinary ectoparasiticides. However, if they are to be used as veterinary products, they must be available in formulations that are suitable for practical application against specific ectoparasites. Here, the efficacies of formulations containing 5% (v/v) lavender or tea tree oil, in combination with two emulsifiers [a surfactant, 5% (w/v) N-lauroylsarcosine sodium salt (SLS), and a soluble polymer, 5% (w/v) polyvinylpyrrolidone (PVP)], with or without 10% coconut oil, were tested in contact bioassays against the donkey chewing louse Bovicola ocellatus (Piaget) (Phthiraptera: Trichodectidae). Residual activity was quantified in open and closed containers; ovicidal efficacy was also examined. Exposure to either of 5% (v/v) lavender or tea tree oils with SLS or PVP resulted in louse mortality of 100%, but when coconut oil was included as an excipient, significantly lower efficacy was recorded. However, the formulations became significantly less effective after 2 h in open containers and 40 h in closed containers. The results confirm that the residual activity of essential oils is relatively transitory and the addition of 10% coconut oil does not prolong the period of insecticidal activity by slowing essential oil evaporation. Too short a period of residual activity is likely to be a significant impediment to the effective practical use of essential oils. However, unlike many synthetic pediculicides, the essential oils tested here were highly ovicidal, which suggests that prolonged residual activity may not be essential to kill newly hatched nymphs after treatment.

  6. Chemical and isotopic compositions in acid residues from various meteorites

    NASA Technical Reports Server (NTRS)

    Kano, N.; Yamakoshi, K.; Matsuzaki, H.; Nogami, K.

    1993-01-01

    We are planning to carry out systematic isotopic investigations of Ru, Mg, etc., in primordial samples. The investigations will be pursued in the context of a study of the pre-history of the solar system. It is hoped that the study will yield direct evidence for processes of nucleosynthesis in the pre-solar stage and detection of extinct radioactive nuclides. In this paper, we present the results of chemical compositions of acid residues obtained from three types of meteorites: Canyon Diablo (IA), Allende (CV3), and Nuevo Mercuro (H5); and the preliminary results of Ru isotopic compositions.

  7. Retinoic acid stimulates essential fatty acid-supplemented human keratinocytes in culture.

    PubMed

    Marcelo, C L; Dunham, W R

    1997-05-01

    The effect of all-trans retinoic acid on the proliferation of essential fatty acid (EFA)-deficient and of EFA-supplemented adult human keratinocytes was investigated. EFA-deficient cell strains were supplied with one of four different fatty acid-supplemented media at the P0 to P1 passage. All-trans retinoic acid at 0.5 or 1.0 microM was added to the cultures at the P1 to P2 passage. At passage P3, and 3 and 7 d thereafter, the cell growth rate was determined. The fatty acid content of cultures grown in each medium was measured using gas chromatography. All the EFA media "normalized" the cellular fatty acid composition and drastically decreased the cell number and total DNA and protein of the cultures. All-trans retinoic acid at 1 microM prevented the loss of cell viability and growth usually associated with EFA supplementation but did not affect the control (EFA deficient) or 18:1 fatty acid-supplemented cultures. All-trans retinoic acid at 1 microM altered the fatty acid content of the EFA-supplemented cultures. A statistically significant increase in 14:0, 14:1, 16:1, 18:1, and 20:4 fatty acids occurred, whereas the amounts of 18:0 and 18:2 fatty acids decreased. The largest changes were in 16:1 fatty acid (8-14%) and 18:2 fatty acid (12-5%). All-trans retinoic acid at 0.5 microM also affected both cell growth and fatty acid composition without induction of the CRABP II message. These studies demonstrate that all-trans retinoic acid stimulates the growth of EFA-supplemented keratinocyte cultures while also altering the fatty acid composition of the cells.

  8. Probing the catalytically essential residues of the alpha-L-arabinofuranosidase from Thermobacillus xylanilyticus.

    PubMed

    Debeche, Takoua; Bliard, Christophe; Debeire, Philippe; O'Donohue, Michael J

    2002-01-01

    The alpha-L-arabinofuranosidase D3 from Thermobacillus xylanilyticus is an arabinoxylan-debranching enzyme which belongs to family 51 of the glycosyl hydrolase classification. Previous studies have indicated that members of this family are retaining enzymes and may form part of the 4/7 superfamily of glycosyl hydrolases. To investigate the active site of alpha-L-arabinofuranosidase D3, we have used sequence alignment, site-directed mutagenesis and kinetic analyses. Likewise, we have shown that Glu(28), Glu(176) and Glu(298) are important for catalytic activity. Kinetic data obtained for the mutant Glu(176)-->Gln, combined with the results of chemical rescue using the mutant Glu(176)-->Ala, have shown that Glu(176) is the acid-base residue. Moreover, NMR analysis of the arabinosyl-azide adduct, which was produced by chemical rescue of the mutant Glu(176)-->Ala, indicated that alpha-L-arabinofuranosidase D3 hydrolyses glycosidic bonds with retention of the anomeric configuration. The results of similar chemical rescue studies using other mutant enzymes suggest that Glu(298) might be the catalytic nucleophile and that Glu(28) is a third member of a catalytic triad which may be responsible for modulating the ionization state of the acid-base and implicated in substrate fixation. Overall, these findings support the hypothesis that alpha-L-arabinofuranosidase D3 belongs to the 4/7 superfamily and provide the first experimental evidence concerning the catalytic apparatus of a family 51 arabinofuranosidase.

  9. Removal of coagulant aluminum from water treatment residuals by acid.

    PubMed

    Okuda, Tetsuji; Nishijima, Wataru; Sugimoto, Mayo; Saka, Naoyuki; Nakai, Satoshi; Tanabe, Kazuyasu; Ito, Junki; Takenaka, Kenji; Okada, Mitsumasa

    2014-09-01

    Sediment sludge during coagulation and sedimentation in drinking water treatment is called "water treatment residuals (WTR)". Polyaluminum chloride (PAC) is mainly used as a coagulant in Japan. The recycling of WTR has been desired; one method for its reuse is as plowed soil. However, WTR reuse in this way is inhibited by the aluminum from the added PAC, because of its high adsorption capacity for phosphate and other fertilizer components. The removal of such aluminum from WTR would therefore be advantageous for its reuse as plowed soil; this research clarified the effect of acid washing on aluminum removal from WTR and on plant growth in the treated soil. The percentage of aluminum removal from raw WTR by sulphuric acid solution was around 90% at pH 3, the percentage decreasing to 40% in the case of a sun-dried sample. The maximum phosphate adsorption capacity was decreased and the available phosphorus was increased by acid washing, with 90% of aluminum removal. The enhancement of Japanese mustard spinach growth and the increased in plant uptake of phosphates following acid washing were observed.

  10. Critical amino acid residues involved in the electrogenic sodium-bicarbonate cotransporter kNBC1-mediated transport.

    PubMed

    Abuladze, Natalia; Azimov, Rustam; Newman, Debra; Sassani, Pakan; Liu, Weixin; Tatishchev, Sergei; Pushkin, Alexander; Kurtz, Ira

    2005-06-15

    We have previously reported a topological model of the electrogenic Na(+)-HCO(3)(-) cotransporter (NBC1) in which the cotransporter spans the plasma membrane 10 times with N- and C-termini localized intracellularly. An analysis of conserved amino acid residues among members of the SLC4 superfamily in both the transmembrane segments (TMs) and intracellular/extracellular loops (ILs/ELs) provided the basis for the mutagenesis approach taken in the present study to determine amino acids involved in NBC1-mediated ion transport. Using large-scale mutagenesis, acidic and basic amino acids putatively involved in ion transport mediated by the predominant variant of NBC1 expressed in the kidney (kNBC1) were mutated to neutral and/or oppositely charged amino acids. All mutant kNBC1 cotransporters were expressed in HEK-293T cells and the Na(+)-dependent base flux of the mutants was determined using intracellular pH measurements with 2',7'-bis-(carboxyethyl)-5(6)-carboxyfluorescein (BCECF). Critical glutamate, aspartate, lysine, arginine and histidine residues in ILs/ELs and TMs were detected that were essential for kNBC1-mediated Na(+)-dependent base transport. In addition, critical phenylalanine, serine, tyrosine, threonine and alanine residues in TMs and ILs/ELs were detected. Furthermore, several amino acid residues in ILs/ELs and TMs were shown to be essential for membrane targeting. The data demonstrate asymmetry of distribution of kNBC1 charged amino acids involved in ion recognition in putative outward-facing and inward-facing conformations. A model summarizing key amino acid residues involved in kNBC1-mediated ion transport is presented.

  11. Critical amino acid residues involved in the electrogenic sodium–bicarbonate cotransporter kNBC1-mediated transport

    PubMed Central

    Abuladze, Natalia; Azimov, Rustam; Newman, Debra; Sassani, Pakan; Liu, Weixin; Tatishchev, Sergei; Pushkin, Alexander; Kurtz, Ira

    2005-01-01

    We have previously reported a topological model of the electrogenic Na+–HCO3− cotransporter (NBC1) in which the cotransporter spans the plasma membrane 10 times with N- and C-termini localized intracellularly. An analysis of conserved amino acid residues among members of the SLC4 superfamily in both the transmembrane segments (TMs) and intracellular/extracellular loops (ILs/ELs) provided the basis for the mutagenesis approach taken in the present study to determine amino acids involved in NBC1-mediated ion transport. Using large-scale mutagenesis, acidic and basic amino acids putatively involved in ion transport mediated by the predominant variant of NBC1 expressed in the kidney (kNBC1) were mutated to neutral and/or oppositely charged amino acids. All mutant kNBC1 cotransporters were expressed in HEK-293T cells and the Na+-dependent base flux of the mutants was determined using intracellular pH measurements with 2′,7′-bis-(carboxyethyl)-5(6)-carboxyfluorescein (BCECF). Critical glutamate, aspartate, lysine, arginine and histidine residues in ILs/ELs and TMs were detected that were essential for kNBC1-mediated Na+-dependent base transport. In addition, critical phenylalanine, serine, tyrosine, threonine and alanine residues in TMs and ILs/ELs were detected. Furthermore, several amino acid residues in ILs/ELs and TMs were shown to be essential for membrane targeting. The data demonstrate asymmetry of distribution of kNBC1 charged amino acids involved in ion recognition in putative outward-facing and inward-facing conformations. A model summarizing key amino acid residues involved in kNBC1-mediated ion transport is presented. PMID:15817634

  12. Expression of the Isoamylase Gene of Flavobacterium odoratum KU in Escherichia coli and Identification of Essential Residues of the Enzyme by Site-Directed Mutagenesis

    PubMed Central

    Abe, Jun-ichi; Ushijima, Chiaki; Hizukuri, Susumu

    1999-01-01

    The isoamylase gene from Flavobacterium odoratum KU was cloned into and expressed in Escherichia coli JM109. The promoter of the gene was successful in E. coli, and the enzyme produced was excreted into the culture medium, depending on the amount of the enzyme expressed. The enzyme found in the culture medium showed almost the same Mr, heat-inactivating constant, and N-terminal sequence as those of the enzyme accumulated in the periplasmic space. This result indicated that the enzyme accumulated in an active form at the periplasm was transported out of the cell. The primary sequence of the enzyme, which was deduced from its nucleotide sequence, showed that the mature enzyme consisted of 741 amino acid residues. By changing five possible residues to Ala independently, it was found that Asp-374, Glu-422, and Asp-497 were essential. The sequences around those residues were highly conserved in isoamylases of different origins and the glycogen operon protein X, GlgX. The comparison of the distance between these essential residues with those of various amylases suggested that the bacterial and plant isoamylase but not GlgX had a longer fourth loop than the other amylases. This longer fourth loop had a possible role in accommodating the long branched chains of native glycogens and starches. PMID:10473430

  13. Role of lysine and acidic amino acid residues on the insecticidal activity of Jackbean urease.

    PubMed

    Real-Guerra, Rafael; Carlini, Célia Regina; Stanisçuaski, Fernanda

    2013-09-01

    Canavalia ensiformis has three isoforms of urease: Jackbean urease (JBU), Jackbean urease II and canatoxin. These isoforms present several biological activities, independent from the enzymatic property, such as entomotoxicity and antifungal properties. The entomotoxic activity is a property of the whole protein, as well as of a 10 kDa peptide released by insect digestive enzymes. Here we have used chemical modification to observe the influence of lysines and acidic residues on JBU enzymatic and insecticidal activities. Chemical modification of lysine residues was performed with dimethylamine-borane complex and formaldehyde, and acidic residues were modified by 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide and ethylenediamine. Derivatized ureases, called JBU-Lys (lysine-modified) and JBU-Ac (acidic residues-modified), were assayed for their biochemical and insecticidal properties. Neither modification altered significantly the kinetic parameters analyzed, indicating that no residue critical for the enzyme activity was affected and that the modifications did not incur in any significant structural alteration. On the other hand, both modifications reduced the toxic activity of the native protein fed to Dysdercus peruvianus. The changes observed in the entomotoxic property of the derivatized proteins reflect alterations in different steps of JBU's toxicity towards insects. JBU-Ac is not susceptible to hydrolysis by insect digestive enzymes, hence impairing the release of toxic peptide(s), while JBU-Lys is processed as the native protein. On the other hand, the antidiuretic effect of JBU on Rhodnius prolixus is altered in JBU-Lys, but not in JBU-Ac. Altogether, these data emphasize the role of lysine and acidic residues on the insecticidal properties of ureases.

  14. Biochemical Roles for Conserved Residues in the Bacterial Fatty Acid-binding Protein Family*

    PubMed Central

    Broussard, Tyler C.; Miller, Darcie J.; Jackson, Pamela; Nourse, Amanda; White, Stephen W.; Rock, Charles O.

    2016-01-01

    Fatty acid kinase (Fak) is a ubiquitous Gram-positive bacterial enzyme consisting of an ATP-binding protein (FakA) that phosphorylates the fatty acid bound to FakB. In Staphylococcus aureus, Fak is a global regulator of virulence factor transcription and is essential for the activation of exogenous fatty acids for incorporation into phospholipids. The 1.2-Å x-ray structure of S. aureus FakB2, activity assays, solution studies, site-directed mutagenesis, and in vivo complementation were used to define the functions of the five conserved residues that define the FakB protein family (Pfam02645). The fatty acid tail is buried within the protein, and the exposed carboxyl group is bound by a Ser-93-fatty acid carboxyl-Thr-61-His-266 hydrogen bond network. The guanidinium of the invariant Arg-170 is positioned to potentially interact with a bound acylphosphate. The reduced thermal denaturation temperatures of the T61A, S93A, and H266A FakB2 mutants illustrate the importance of the hydrogen bond network in protein stability. The FakB2 T61A, S93A, and H266A mutants are 1000-fold less active in the Fak assay, and the R170A mutant is completely inactive. All FakB2 mutants form FakA(FakB2)2 complexes except FakB2(R202A), which is deficient in FakA binding. Allelic replacement shows that strains expressing FakB2 mutants are defective in fatty acid incorporation into phospholipids and virulence gene transcription. These conserved residues are likely to perform the same critical functions in all bacterial fatty acid-binding proteins. PMID:26774272

  15. Standard test method for acidity of distillation residues or hydrocarbon liquids

    SciTech Connect

    Not Available

    1980-01-01

    This method covers the qualitative determination of the acidity of the distillation residue from a gasoline. The sample of distillation residue or hydrocarbon liquid is shaken with water and the aqueous layer tested for acidity to methyl orange. Some petroleum products are treated with mineral acid as part of the refining procedure. Obviously, any residual mineral acid in a petroleum product is undesirable. The absence of a positive indication in the test for acidity of the distillation residue or aqueous extract of a hydrocarbon liquid is an assurance of the care used in refining the fuel or solvent.

  16. New insights into the catalytic mechanism of histidine phosphatases revealed by a functionally essential arginine residue within the active site of the Sts phosphatases.

    PubMed

    San Luis, Boris; Nassar, Nicolas; Carpino, Nick

    2013-07-01

    Sts (suppressor of T-cell receptor signalling)-1 and Sts-2 are HPs (histidine phosphatases) that negatively regulate TCR (T-cell receptor) signalling pathways, including those involved in cytokine production. HPs play key roles in such varied biological processes as metabolism, development and intracellular signalling. They differ considerably in their primary sequence and substrate specificity, but possess a catalytic core formed by an invariant quartet of active-site residues. Two histidine and two arginine residues cluster together within the HP active site and are thought to participate in a two-step dephosphorylation reaction. To date there has been little insight into any additional residues that might play an important functional role. In the present study, we identify and characterize an additional residue within the Sts phosphatases (Sts-1 Arg383 or Sts-2 Arg369) that is critical for catalytic activity and intracellular function. Mutation of Sts-1 Arg383 to an alanine residue compromises the enzyme's activity and renders Sts-1 unable to suppress TCR-induced cytokine induction. Of the multiple amino acids substituted for Arg383, only lysine partially rescues the catalytic activity of Sts-1. Although Sts-1 Arg383 is conserved in all Sts homologues, it is only conserved in one of the two sub-branches of HPs. The results of the present study highlight an essential role for Sts-1 phosphatase activity in regulating T-cell activation and add a new dimension of complexity to our understanding of HP catalytic activity.

  17. Essential amino acids: master regulators of nutrition and environmental footprint?

    PubMed Central

    Tessari, Paolo; Lante, Anna; Mosca, Giuliano

    2016-01-01

    The environmental footprint of animal food production is considered several-fold greater than that of crops cultivation. Therefore, the choice between animal and vegetarian diets may have a relevant environmental impact. In such comparisons however, an often neglected issue is the nutritional value of foods. Previous estimates of nutrients’ environmental footprint had predominantly been based on either food raw weight or caloric content, not in respect to human requirements. Essential amino acids (EAAs) are key parameters in food quality assessment. We re-evaluated here the environmental footprint (expressed both as land use for production and as Green House Gas Emission (GHGE), of some animal and vegetal foods, titrated to provide EAAs amounts in respect to human requirements. Production of high-quality animal proteins, in amounts sufficient to match the Recommended Daily Allowances of all the EAAs, would require a land use and a GHGE approximately equal, greater o smaller (by only ±1-fold), than that necessary to produce vegetal proteins, except for soybeans, that exhibited the smallest footprint. This new analysis downsizes the common concept of a large advantage, in respect to environmental footprint, of crops vs. animal foods production, when human requirements of EAAs are used for reference. PMID:27221394

  18. Fatty acid facts, Part I. Essential fatty acids as treatment for depression, or food for mood?

    PubMed

    Pawels, E K J; Volterrani, D

    2008-10-01

    The epidemic character of depressive disorders has prompted further research into dietary habits that could make an etiological contribution. One clear change in the diet of the population in developed countries has been the replacement of omega-3 polyunsaturated fatty acids by saturated fats and trans-fats as well as by omega-6 polyunsaturated fatty acids. Omega-3 and omega-6 fatty acids are essential fatty acids, and the members of the -3 and -6 series are crucial for human health. In biochemical processes there is a competition between these two series. A higher dietary intake of omega-6 results in the excessive incorporation of these molecules in the cell membrane with numerous pathological consequences, presumably due to the formation of proinflammatory eicosanoids. Members of the omega-3 family and their derivatives modulate the inflammatory action. Essential fatty acids play a major role in brain development and brain functioning. The omega-3 series members docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) provide fluidity to the cell membrane, facilitating certain processes including neurotransmission and ion channel flow. It is thought that omega-3 deficiency during the fetal and postnatal period may have a long-term effect at various levels. Epidemiological studies have demonstrated a positive association between omega-3 deficits and mood disorders. As for treatment, there is convincing evidence that add-on omega-3 fatty acids to standard antidepressant pharmacotherapy results in improved mood. There is no evidence that fatty acid monotherapy has a mood-elevating effect, with a possible exception for childhood depression. There are indications that omega-3 has a prophylactic effect on perinatal depression and has a negative effect on natural killer cell activity and T-lymphocyte function. These observations need further study in view of the popularity of self-medication.

  19. 40 CFR 180.202 - p-Chlorophenoxyacetic acid; tolerances for residues.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 23 2010-07-01 2010-07-01 false p-Chlorophenoxyacetic acid; tolerances... Tolerances § 180.202 p-Chlorophenoxyacetic acid; tolerances for residues. (a) General. A tolerance is established for the combined residues of the plant regulator p-chlorophenoxyacetic acid and its metabolite...

  20. 40 CFR 180.202 - p-Chlorophenoxyacetic acid; tolerances for residues.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 24 2014-07-01 2014-07-01 false p-Chlorophenoxyacetic acid; tolerances... Tolerances § 180.202 p-Chlorophenoxyacetic acid; tolerances for residues. (a) General. A tolerance is established for the combined residues of the plant regulator p-chlorophenoxyacetic acid and its metabolite...

  1. 40 CFR 180.202 - p-Chlorophenoxyacetic acid; tolerances for residues.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 24 2011-07-01 2011-07-01 false p-Chlorophenoxyacetic acid; tolerances... Tolerances § 180.202 p-Chlorophenoxyacetic acid; tolerances for residues. (a) General. A tolerance is established for the combined residues of the plant regulator p-chlorophenoxyacetic acid and its metabolite...

  2. 40 CFR 180.202 - p-Chlorophenoxyacetic acid; tolerances for residues.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 25 2012-07-01 2012-07-01 false p-Chlorophenoxyacetic acid; tolerances... Tolerances § 180.202 p-Chlorophenoxyacetic acid; tolerances for residues. (a) General. A tolerance is established for the combined residues of the plant regulator p-chlorophenoxyacetic acid and its metabolite...

  3. 40 CFR 180.202 - p-Chlorophenoxyacetic acid; tolerances for residues.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 25 2013-07-01 2013-07-01 false p-Chlorophenoxyacetic acid; tolerances... Tolerances § 180.202 p-Chlorophenoxyacetic acid; tolerances for residues. (a) General. A tolerance is established for the combined residues of the plant regulator p-chlorophenoxyacetic acid and its metabolite...

  4. 40 CFR 180.325 - 2-(m-Chlorophenoxy) propionic acid; tolerances for residues.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 23 2010-07-01 2010-07-01 false 2-(m-Chlorophenoxy) propionic acid... Tolerances § 180.325 2-(m-Chlorophenoxy) propionic acid; tolerances for residues. (a) General. A tolerance is established for negligible residues of the plant regulator 2-(m-chlorophenoxy) propionic acid from...

  5. Site-specific PEGylation of therapeutic proteins via optimization of both accessible reactive amino acid residues and PEG derivatives.

    PubMed

    Zhang, Chun; Yang, Xiao-lan; Yuan, Yong-hua; Pu, Jun; Liao, Fei

    2012-08-01

    Modification of accessible amino acid residues with poly(ethylene glycol) [PEG] is a widely used technique for formulating therapeutic proteins. In practice, site-specific PEGylation of all selected/engineered accessible nonessential reactive residues of therapeutic proteins with common activated PEG derivatives is a promising strategy to concomitantly improve pharmacokinetics, allow retention of activity, alleviate immunogenicity, and avoid modification isomers. Specifically, through molecular engineering of a therapeutic protein, accessible essential residues reactive to an activated PEG derivative are substituted with unreactive residues provided that protein activity is retained, and a limited number of accessible nonessential reactive residues with optimized distributions are selected/introduced. Subsequently, all accessible nonessential reactive residues are completely PEGylated with the activated PEG derivative in great excess. Branched PEG derivatives containing new PEG chains with negligible metabolic toxicity are more desirable for site-specific PEGylation. Accordingly, for the successful formulation of therapeutic proteins, optimization of the number and distributions of accessible nonessential reactive residues via molecular engineering can be integrated with the design of large-sized PEG derivatives to achieve site-specific PEGylation of all selected/engineered accessible reactive residues.

  6. Octanoic acid in alcohol-responsive essential tremor

    PubMed Central

    McCrossin, Gayle; Lungu, Codrin; Considine, Elaine; Toro, Camilo; Nahab, Fatta B.; Auh, Sungyoung; Buchwald, Peter; Grimes, George J.; Starling, Judith; Potti, Gopal; Scheider, Linda; Kalowitz, Daniel; Bowen, Daniel; Carnie, Andrea; Hallett, Mark

    2013-01-01

    Objective: To assess safety and efficacy of an oral, single, low dose of octanoic acid (OA) in subjects with alcohol-responsive essential tremor (ET). Methods: We conducted a double-blind, placebo-controlled, crossover, phase I/II clinical trial evaluating the effect of 4 mg/kg OA in 19 subjects with ET. The primary outcome was accelerometric postural tremor power of the dominant hand 80 minutes after administration. Secondary outcomes included digital spiral analysis, pharmacokinetic sampling, as well as safety measures. Results: OA was safe and well tolerated. Nonserious adverse events were mild (Common Terminology Criteria for Adverse Events grade 1) and equally present after OA and placebo. At the primary outcome, OA effects were not different from placebo. Secondary outcome analyses of digital spiral analysis, comparison across the entire time course in weighted and nonweighted accelerometry, as well as nondominant hand tremor power did not show a benefit of OA over placebo. The analysis of individual time points showed that OA improved tremor at 300 minutes (dominant hand, F1,16 = 5.49, p = 0.032 vs placebo), with a maximum benefit at 180 minutes after OA (both hands, F1,16 = 6.1, p = 0.025). Conclusions: Although the effects of OA and placebo at the primary outcome were not different, secondary outcome measures suggest superiority of OA in reducing tremor at later time points, warranting further trials at higher dose levels. Classification of evidence: This study provides Class I evidence that a single 4-mg/kg dose of OA is not effective in reducing postural tremor in patients with ET at a primary outcome of 80 minutes, but is effective for a secondary outcome after 180 minutes. PMID:23408867

  7. Effects of ursodeoxycholic acid treatment on essential fatty acid deficiency in patients with biliary atresia.

    PubMed

    Yamashiro, Y; Ohtsuka, Y; Shimizu, T; Nittono, H; Urao, M; Miyano, T; Kawakami, S; Hayasawa, H

    1994-03-01

    To assess whether ursodeoxycholic acid (UDCA) treatment has any beneficial effect on essential fatty acid (EFA) deficiency in patients who have had a Kasai operation for extrahepatic atresia (EBA), responses of serum fatty acids to UDCA administration (15 mg/kg/d) were investigated in eight jaundice-free patients and in eight patients with jaundice (serum total bilirubin > or = 1.0 mg/dL). All patients were also given taurine supplementation (100 mg/kg/d). Serum fatty acid composition was determined before and 6 months after UDCA treatment. Serum total bile acid concentration and serum total bilirubin value, as a part of conventional liver function tests, were measured before and during UDCA therapy. Before UDCA treatment, the concentrations of linoleic acid and arachidonic acid were significantly lower (P > .05 for the former; P > .01 for the latter) in both the jaundice and jaundice-free groups than in the controls. After 6 months of treatment, the linoleic acid concentration significantly increased (P > .05), to the normal range, in the jaundice-free group, but not in the jaundice group. The arachidonic acid concentration did not increase significantly in either group. The serum total bile acid concentration was lower in six of the eight jaundice-free patients and in four of the eight jaundice patients. The serum total bilirubin value decreased in six of the eight jaundice-free patients and in four of the eight jaundice patients; however, the degree of improvement was not statistically significant in either group. No side effects developed, and there were no changes in blood chemistry values unrelated to liver disease.(ABSTRACT TRUNCATED AT 250 WORDS)

  8. Mutation of aspartic acid residues in the fructosyltransferase of Streptococcus salivarius ATCC 25975.

    PubMed Central

    Song, D D; Jacques, N A

    1999-01-01

    The site-directed mutated fructosyltransferases (Ftfs) of Streptococcus salivarius ATCC 25975, D312E, D312S, D312N and D312K were all active at 37 degrees C, indicating that Asp-312 present in the 'sucrose box' was not the nucleophilic Asp residue responsible for the formation of a covalent fructosyl-enzyme intermediate required for enzyme activity. Analysis of the kinetic constants of the purified mutated forms of the enzyme showed that Asp-312 was most likely an essential amino acid involved in determining acceptor recognition and/or stabilizing a beta-turn in the protein. In contrast, when the Asp-397 of the Ftf present in the conserved triplet RDP motif of all 60 bacterial and plant family-32 glycosylhydrolases was mutated to a Ser residue, both sucrose hydrolysis and polymerization ceased. Tryptophan emission spectra confirmed that this mutation did not alter protein structure. Comparison of published data from other site-directed mutated enzymes implicated the Asp residue in the RDP motif as the one that may form a transient covalent fructosyl intermediate during the catalysis of sucrose by the Ftf of S. salivarius. PMID:10548559

  9. The amino acid sequence around the active-site cysteine and histidine residues, and the buried cysteine residue in ficin.

    PubMed

    Husain, S S; Lowe, G

    1970-04-01

    Ficin that had been prepared from the latex of Ficus glabrata by salt fractionation and chromatography on carboxymethylcellulose was completely and irreversibly inhibited with 1,3-dibromo[2-(14)C]acetone and then treated with N-(4-dimethylamino-3,5-dinitrophenyl)maleimide in 6m-guanidinium chloride. After reduction and carboxymethylation of the labelled protein, it was digested with trypsin and alpha-chymotrypsin. Two radioactive peptides and two coloured peptides were isolated chromatographically and their sequences determined. The radioactive peptides revealed the amino acid sequences around the active-site cysteine and histidine residues and showed a high degree of homology with the omino acid sequence around the active-site cysteine and histidine residues in papain. The coloured peptides allowed the amino acid sequence around the buried cysteine residue in ficin to be determined.

  10. 40 CFR 180.297 - N-1-Naphthyl phthalamic acid; tolerances for residues.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...; tolerances for residues. 180.297 Section 180.297 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) PESTICIDE PROGRAMS TOLERANCES AND EXEMPTIONS FOR PESTICIDE CHEMICAL RESIDUES IN FOOD Specific Tolerances § 180.297 N-1-Naphthyl phthalamic acid; tolerances for residues. (a) General. Tolerances...

  11. 40 CFR 180.297 - N-1-Naphthyl phthalamic acid; tolerances for residues.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...; tolerances for residues. 180.297 Section 180.297 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) PESTICIDE PROGRAMS TOLERANCES AND EXEMPTIONS FOR PESTICIDE CHEMICAL RESIDUES IN FOOD Specific Tolerances § 180.297 N-1-Naphthyl phthalamic acid; tolerances for residues. (a) General. Tolerances...

  12. 40 CFR 180.297 - N-1-Naphthyl phthalamic acid; tolerances for residues.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...; tolerances for residues. 180.297 Section 180.297 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) PESTICIDE PROGRAMS TOLERANCES AND EXEMPTIONS FOR PESTICIDE CHEMICAL RESIDUES IN FOOD Specific Tolerances § 180.297 N-1-Naphthyl phthalamic acid; tolerances for residues. (a) General. Tolerances...

  13. 40 CFR 180.297 - N-1-Naphthyl phthalamic acid; tolerances for residues.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...; tolerances for residues. 180.297 Section 180.297 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) PESTICIDE PROGRAMS TOLERANCES AND EXEMPTIONS FOR PESTICIDE CHEMICAL RESIDUES IN FOOD Specific Tolerances § 180.297 N-1-Naphthyl phthalamic acid; tolerances for residues. (a) General. Tolerances...

  14. 40 CFR 180.297 - N-1-Naphthyl phthalamic acid; tolerances for residues.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...; tolerances for residues. 180.297 Section 180.297 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) PESTICIDE PROGRAMS TOLERANCES AND EXEMPTIONS FOR PESTICIDE CHEMICAL RESIDUES IN FOOD Specific Tolerances § 180.297 N-1-Naphthyl phthalamic acid; tolerances for residues. (a) General. Tolerances...

  15. Identification of catalytically essential residues in Escherichia coli esterase by site-directed mutagenesis.

    PubMed

    Haruki, M; Oohashi, Y; Mizuguchi, S; Matsuo, Y; Morikawa, M; Kanaya, S

    1999-07-09

    Escherichia coli esterase (EcE) is a member of the hormone-sensitive lipase family. We have analyzed the roles of the conserved residues in this enzyme (His103, Glu128, Gly163, Asp164, Ser165, Gly167, Asp262, Asp266 and His292) by site-directed mutagenesis. Among them, Gly163, Asp164, Ser165, and Gly167 are the components of a G-D/E-S-A-G motif. We showed that Ser165, Asp262, and His292 are the active-site residues of the enzyme. We also showed that none of the other residues, except for Asp164, is critical for the enzymatic activity. The mutation of Asp164 to Ala dramatically reduced the catalytic efficiency of the enzyme by the factor of 10(4) without seriously affecting the substrate binding. This residue is probably structurally important to make the conformation of the active-site functional.

  16. Essential amino acid supplementation in patients following total knee arthroplasty

    PubMed Central

    Dreyer, Hans C.; Strycker, Lisa A.; Senesac, Hilary A.; Hocker, Austin D.; Smolkowski, Keith; Shah, Steven N.; Jewett, Brian A.

    2013-01-01

    Background. By the year 2030, 3.48 million older U.S. adults are projected to undergo total knee arthroplasty (TKA). Following this surgery, considerable muscle atrophy occurs, resulting in decreased strength and impaired functional mobility. Essential amino acids (EAAs) have been shown to attenuate muscle loss during periods of reduced activity and may be beneficial for TKA patients. Methods. We used a double-blind, placebo-controlled, randomized clinical trial with 28 older adults undergoing TKA. Patients were randomized to ingest either 20 g of EAAs (n = 16) or placebo (n = 12) twice daily between meals for 1 week before and 2 weeks after TKA. At baseline, 2 weeks, and 6 weeks after TKA, an MRI was performed to determine mid-thigh muscle and adipose tissue volume. Muscle strength and functional mobility were also measured at these times. Results. TKA patients receiving placebo exhibited greater quadriceps muscle atrophy, with a –14.3 ± 3.6% change from baseline to 2 weeks after surgery compared with –3.4 ± 3.1% for the EAA group (F = 5.16, P = 0.036) and a –18.4 ± 2.3% change from baseline to 6 weeks after surgery for placebo versus –6.2 ± 2.2% for the EAA group (F = 14.14, P = 0.001). EAAs also attenuated atrophy in the nonoperated quadriceps and in the hamstring and adductor muscles of both extremities. The EAA group performed better at 2 and 6 weeks after surgery on functional mobility tests (all P < 0.05). Change in quadriceps muscle atrophy was significantly associated with change in functional mobility (F = 5.78, P = 0.021). Conclusion. EAA treatment attenuated muscle atrophy and accelerated the return of functional mobility in older adults following TKA. Trial registration. Clinicaltrials.gov NCT00760383. Funding. Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), Office of the Director (OD), and the National Institutes of Health Office of Dietary Supplements (ODS), NIH grant K01HD057332, and the Medical

  17. Oxidation in Acidic Medium of Lignins from Agricultural Residues

    NASA Astrophysics Data System (ADS)

    Labat, Gisele Aparecida Amaral; Gonçalves, Adilson Roberto

    Agricultural residues as sugarcane straw and bagasse are burned in boilers for generation of energy in sugar and alcohol industries. However, excess of those by-products could be used to obtain products with higher value. Pulping process generates cellulosic pulps and lignin. The lignin could be oxidized and applied in effluent treatments for heavy metal removal. Oxidized lignin presents very strong chelating properties. Lignins from sugarcane straw and bagasse were obtained by ethanol-water pulping. Oxidation of lignins was carried out using acetic acid and Co/Mn/Br catalytical system at 50, 80, and 115 °C for 5 h. Kinetics of the reaction was accomplished by measuring the UV-visible region. Activation energy was calculated for lignins from sugarcane straw and bagasse (34.2 and 23.4 kJ mol-1, respectively). The first value indicates higher cross-linked formation. Fourier-transformed infrared spectroscopy data of samples collected during oxidation are very similar. Principal component analysis applied to spectra shows only slight structure modifications in lignins after oxidation reaction.

  18. Pyrolytic characteristics of biomass acid hydrolysis residue rich in lignin.

    PubMed

    Huang, Yanqin; Wei, Zhiguo; Yin, Xiuli; Wu, Chuangzhi

    2012-01-01

    Pyrolytic characteristics of acid hydrolysis residue (AHR) of corncob and pinewood (CAHR, WAHR) were investigated using a thermo-gravimetric analyzer (TGA) and a self-designed pyrolysis apparatus. Gasification reactivity of CAHR char was then examined using TGA and X-ray diffractometer. Result of TGA showed that thermal degradation curves of AHR descended smoothly along with temperature increasing from 150 °C to 850 °C, while a "sharp mass loss stage" for original biomass feedstock (OBF) was observed. Char yield from AHR (42.64-30.35 wt.%) was found to be much greater than that from OBF (26.4-19.15 wt.%). In addition, gasification reactivity of CAHR char was lower than that of corncob char, and there was big difference in micro-crystallite structure. It was also found that CAHR char reactivity decreased with pyrolysis temperature, but increased with pyrolysis heating rate and gasification temperature at 850-950 °C. Furthermore, CAHR char reactivity performed better under steam atmosphere than under CO2 atmosphere.

  19. Evaluation of residues of essential oil components in honey after different anti-varroa treatments.

    PubMed

    Adamczyk, Sabine; Lázaro, Regina; Pérez-Arquillué, Consuelo; Conchello, Pilar; Herrera, Antonio

    2005-12-28

    Apiary trials on the use of three different treatments (Apilife Var, thymol solution in olive oil, and thymol solution in ethanol) for the control of Varroa destructor were conducted in Aragon (northeastern Spain). For the evaluation of the presence of residues of these treatments in honey an analytical method was developed. The method is applied to analyze honey samples before and after treatments with the acaricides mentioned. A solid-phase extraction on trifunctional silane SPE C18 cartridge and gas chromatography separation using a flame ionization detector allow reliable and precise determination of residues of thymol, menthol, eucalyptol, and camphor in honey. The results indicate that camphor is present in only low concentrations, residues of eucalyptol or menthol were not found at all, and only thymol left residues in high concentrations. Residues of thymol found in honey collected from the beehives ranged from 0.75 to 8.20 microg/g for Apilife Var, from 0.03 to 6.30 microg/g for thymol solution in olive oil, and from 0.05 to 6.20 microg/g for thymol solution in ethanol. Even so, natural treatments can be considered to be good alternatives for synthetic acaricides, especially because they do not represent a sanitary risk.

  20. 40 CFR 180.318 - 4-(2-Methyl-4-chlorophenoxy) butyric acid; tolerance for residues.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...)butanoic acid, and its metabolite MCPA, (4-chloro-2-methylphenoxy)acetic acid, in or on the following food... acid; tolerance for residues. 180.318 Section 180.318 Protection of Environment ENVIRONMENTAL... FOOD Specific Tolerances § 180.318 4-(2-Methyl-4-chlorophenoxy) butyric acid; tolerance for...

  1. 40 CFR 180.318 - 4-(2-Methyl-4-chlorophenoxy) butyric acid; tolerance for residues.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...)butanoic acid, and its metabolite MCPA, (4-chloro-2-methylphenoxy)acetic acid, in or on the following food... acid; tolerance for residues. 180.318 Section 180.318 Protection of Environment ENVIRONMENTAL... FOOD Specific Tolerances § 180.318 4-(2-Methyl-4-chlorophenoxy) butyric acid; tolerance for...

  2. 40 CFR 180.318 - 4-(2-Methyl-4-chlorophenoxy) butyric acid; tolerance for residues.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...)butanoic acid, and its metabolite MCPA, (4-chloro-2-methylphenoxy)acetic acid, in or on the following food... acid; tolerance for residues. 180.318 Section 180.318 Protection of Environment ENVIRONMENTAL... FOOD Specific Tolerances § 180.318 4-(2-Methyl-4-chlorophenoxy) butyric acid; tolerance for...

  3. 40 CFR 180.318 - 4-(2-Methyl-4-chlorophenoxy) butyric acid; tolerance for residues.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...)butanoic acid, and its metabolite MCPA, (4-chloro-2-methylphenoxy)acetic acid, in or on the following food... acid; tolerance for residues. 180.318 Section 180.318 Protection of Environment ENVIRONMENTAL... FOOD Specific Tolerances § 180.318 4-(2-Methyl-4-chlorophenoxy) butyric acid; tolerance for...

  4. 40 CFR 180.318 - 4-(2-Methyl-4-chlorophenoxy) butyric acid; tolerance for residues.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...)butanoic acid, and its metabolite MCPA, (4-chloro-2-methylphenoxy)acetic acid, in or on the following food... acid; tolerance for residues. 180.318 Section 180.318 Protection of Environment ENVIRONMENTAL... FOOD Specific Tolerances § 180.318 4-(2-Methyl-4-chlorophenoxy) butyric acid; tolerance for...

  5. Properties of nanocellulose isolated from corncob residue using sulfuric acid, formic acid, oxidative and mechanical methods.

    PubMed

    Liu, Chao; Li, Bin; Du, Haishun; Lv, Dong; Zhang, Yuedong; Yu, Guang; Mu, Xindong; Peng, Hui

    2016-10-20

    In this work, nanocellulose was extracted from bleached corncob residue (CCR), an underutilized lignocellulose waste from furfural industry, using four different methods (i.e. sulfuric acid hydrolysis, formic acid (FA) hydrolysis, 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO)-mediated oxidation, and pulp refining, respectively). The self-assembled structure, morphology, dimension, crystallinity, chemical structure and thermal stability of prepared nanocellulose were investigated. FA hydrolysis produced longer cellulose nanocrystals (CNCs) than the one obtained by sulfuric acid hydrolysis, and resulted in high crystallinity and thermal stability due to its preferential degradation of amorphous cellulose and lignin. The cellulose nanofibrils (CNFs) with fine and individualized structure could be isolated by TEMPO-mediated oxidation. In comparison with other nanocellulose products, the intensive pulp refining led to the CNFs with the longest length and the thickest diameter. This comparative study can help to provide an insight into the utilization of CCR as a potential source for nanocellulose production.

  6. Dihedral angle preferences of DNA and RNA binding amino acid residues in proteins.

    PubMed

    Ponnuraj, Karthe; Saravanan, Konda Mani

    2017-04-01

    A protein can interact with DNA or RNA molecules to perform various cellular processes. Identifying or analyzing DNA/RNA binding site amino acid residues is important to understand molecular recognition process. It is quite possible to accurately model DNA/RNA binding amino acid residues in experimental protein-DNA/RNA complex by using the electron density map whereas, locating/modeling the binding site amino acid residues in the predicted three dimensional structures of DNA/RNA binding proteins is still a difficult task. Considering the above facts, in the present work, we have carried out a comprehensive analysis of dihedral angle preferences of DNA and RNA binding site amino acid residues by using a classical Ramachandran map. We have computed backbone dihedral angles of non-DNA/RNA binding residues and used as control dataset to make a comparative study. The dihedral angle preference of DNA and RNA binding site residues of twenty amino acid type is presented. Our analysis clearly revealed that the dihedral angles (φ, ψ) of DNA/RNA binding amino acid residues prefer to occupy (-89° to -60°, -59° to -30°) bins. The results presented in this paper will help to model/locate DNA/RNA binding amino acid residues with better accuracy.

  7. Chlorine residuals and haloacetic acid reduction in rapid sand filtration.

    PubMed

    Chuang, Yi-Hsueh; Wang, Gen-Shuch; Tung, Hsin-hsin

    2011-11-01

    It is quite rare to find biodegradation in rapid sand filtration for drinking water treatment. This might be due to frequent backwashes and low substrate levels. High chlorine concentrations may inhibit biofilm development, especially for plants with pre-chlorination. However, in tropical or subtropical regions, bioactivity on the sand surface may be quite significant due to high biofilm development--a result of year-round high temperature. The objective of this study is to explore the correlation between biodegradation and chlorine concentration in rapid sand filters, especially for the water treatment plants that practise pre-chlorination. In this study, haloacetic acid (HAA) biodegradation was found in conventional rapid sand filters practising pre-chlorination. Laboratory column studies and field investigations were conducted to explore the association between the biodegradation of HAAs and chlorine concentrations. The results showed that chlorine residual was an important factor that alters bioactivity development. A model based on filter influent and effluent chlorine was developed for determining threshold chlorine for biodegradation. From the model, a temperature independent chlorine concentration threshold (Cl(threshold)) for biodegradation was estimated at 0.46-0.5mgL(-1). The results imply that conventional filters with adequate control could be conducive to bioactivity, resulting in lower HAA concentrations. Optimizing biodegradable disinfection by-product removal in conventional rapid sand filter could be achieved with minor variation and a lower-than-Cl(threshold) influent chlorine concentration. Bacteria isolation was also carried out, successfully identifying several HAA degraders. These degraders are very commonly seen in drinking water systems and can be speculated as the main contributor of HAA loss.

  8. Phosphorous acid residues in apples after foliar fertilization: results of field trials.

    PubMed

    Malusà, E; Tosi, L

    2005-06-01

    The levels of phosphorous acid residues in apples after foliar fertilization with P fertilizers and after treatment with a phosphonate fungicide (Fosetyl-Al) were determined and compared. Two field trials and a glasshouse experiment, using different genotypes and plants of different age, were carried out and monitored over a three-year period. Phosphorous acid residues were found in apples after application of foliar P fertilizers. Concentrations of the residues ranged between 0.02 and 14 mg kg(-1) depending on the phosphorous acid content in the fertilizer used and the plant size and yield. The treatments induced an accumulation of the residue in the course of the experiments, which in some cases reached a level exceeding the maximum limit set by EU legislation. Residues were also detected in other plant organs, i.e., roots and buds. Plants treated with Fosetyl-Al contained phosphorous acid residues in their fruits and buds two years after the suspension of the treatment, suggesting a long-term persistence of the substance in plant storage organs. A second experiment, involving treatment of trees with seven foliar fertilizers of different composition, also induced accumulation of phosphorous acid residues in fruits. It is concluded that a wide array of foliar products containing phosphorous acid, even as a minor component, could mimic the residue effect of phosphonate fungicide treatments.

  9. Mutational analysis of extracellular cysteine residues of rat secretin receptor shows that disulfide bridges are essential for receptor function.

    PubMed

    Vilardaga, J P; Di Paolo, E; Bialek, C; De Neef, P; Waelbroeck, M; Bollen, A; Robberecht, P

    1997-05-15

    We attempted to express point-mutant secretin receptors where each of the 10 extracellular Cys residues was replaced by a Ser residue, in Chinese hamster ovary (CHO) cells. Six of the point-mutant receptors (C24-->S, C44-->S, C53-->S, C67-->S, C85-->S and C101-->S) could not be detected by binding or functional studies: the mutations resulted in functional inactivation of the receptor. In contrast, the four other point-mutant receptors (C11-->S, C186-->S, C193-->S and C263-->S) were able to bind poorly 125I-secretin, and to activate adenylate cyclase with high secretin EC50 values. These results suggest that cysteine residues 24, 44, 53, 67, 85 and 101 are necessary for receptor function, and that the two putative disulfide bridges formed by cysteine residues 11, 186, 193 and 263 are functionally relevant, but not essential for receptor expression. Secretin activated the adenylate cyclase through the quadruple mutant (C11,186,193,263-->S), the four triple mutants, and through double mutants C186,193-->S and C186,263-->S with a very high (microM) EC50 value, suggesting that, in the wild-type receptor, disulfide bridges are formed between C11-C186, and between C193-C263. Prior treatment with dithiothreitol resulted in a marked EC50 increase of the wild-type receptor and of those receptors with at least the two cysteine residues in positions 11 and 186, suggesting that the C11-C186 (but not the C193-C263) disulfide bridge was accessible to this reducing agent. Several results nevertheless indicated that, in mutant receptors, alternative disulfide bridges can be formed between cysteine 186 and cysteine 193 or 263, suggesting that these three residues are in close spatial proximity in the wild-type receptor.

  10. Negative Confounding by Essential Fatty Acids in Methylmercury Neurotoxicity Associations

    PubMed Central

    Choi, Anna L; Mogensen, Ulla B.; Bjerve, Kristian S.; Debes, Frodi; Weihe, Pal; Grandjean, Philippe; Budtz-Jørgensen, Esben

    2014-01-01

    Background Methylmercury, a worldwide contaminant of fish and seafood, can cause adverse effects on the developing nervous system. However, long-chain n-3 polyunsaturated fatty acids in seafood provide beneficial effects on brain development. Negative confounding will likely result in underestimation of both mercury toxicity and nutrient benefits unless mutual adjustment is included in the analysis. Methods We examined these associations in 176 Faroese children, in whom prenatal methylmercury exposure was assessed from mercury concentrations in cord blood and maternal hair. The relative concentrations of fatty acids were determined in cord serum phospholipids. Neuropsychological performance in verbal, motor, attention, spatial, and memory functions was assessed at 7 years of age. Multiple regression and structural equation models (SEMs) were carried out to determine the confounder-adjusted associations with methylmercury exposure. Results A short delay recall (in percent change) in the California Verbal Learning Test (CVLT) was associated with a doubling of cord blood methylmercury (−18.9, 95% confidence interval [CI] = −36.3, −1.51). The association became stronger after the inclusion of fatty acid concentrations in the analysis (−22.0, 95% confidence interval [CI] = −39.4, −4.62). In structural equation models, poorer memory function (corresponding to a lower score in the learning trials and short delay recall in CVLT) was associated with a doubling of prenatal exposure to methylmercury after the inclusion of fatty acid concentrations in the analysis (−1.94, 95% CI = −3.39, −0.49). Conclusions Associations between prenatal exposure to methylmercury and neurobehavioral deficits in memory function at school age were strengthened after fatty acid adjustment, thus suggesting that n-3 fatty acids need to be included in analysis of similar studies to avoid underestimation of the associations with methylmercury exposure. PMID:24561639

  11. 40 CFR 180.311 - Cacodylic acid; tolerances for residues.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...) PESTICIDE PROGRAMS TOLERANCES AND EXEMPTIONS FOR PESTICIDE CHEMICAL RESIDUES IN FOOD Specific Tolerances... million Expiration/Revocation Date Cotton, undelinted seed 2.8 1/1/12 (b) Section 18 emergency...

  12. Conversion of Undaria pinnatifida residue to glycolic acid with recyclable methylamine in low temperature hydrothermal liquefaction.

    PubMed

    Chen, Yongxing; Ren, Xiulian; Wei, Qifeng

    2017-03-01

    The conversion of Undaria pinnatifida residue to glycolic acid was carried out using methylamine as catalyst by hydrothermal method at relatively low temperature. GC-MS and HPLC were used to identify the composition of bio-oil and liquid products which provide the knowledge of the chemical reaction pathways of the hydrothermal liquefaction. The main liquid product was organic acid which contained glycolic acid, lactic acid, formic acid and acetic acid. And the major organic acid was glycolic acid with the highest yield of 46.52% or 33.98% of dry biomass. Methylamine promoted the dissolution of cellulose from Undaria pinnatifida residue, and significantly improved the yield of glycolic acid. The mechanism of HTL was investigated and the results show that the carbocation C3 was attacked by methylamine molecule which led to the high yield of glycolic acid. In addition, the recovery of methylamine was studied and the highest recovery rate reached 99.28%.

  13. None of the rotor residues of F1-ATPase are essential for torque generation.

    PubMed

    Chiwata, Ryohei; Kohori, Ayako; Kawakami, Tomonari; Shiroguchi, Katsuyuki; Furuike, Shou; Adachi, Kengo; Sutoh, Kazuo; Yoshida, Masasuke; Kinosita, Kazuhiko

    2014-05-20

    F1-ATPase is a powerful rotary molecular motor that can rotate an object several hundred times as large as the motor itself against the viscous friction of water. Forced reverse rotation has been shown to lead to ATP synthesis, implying that the mechanical work against the motor's high torque can be converted into the chemical energy of ATP. The minimal composition of the motor protein is α3β3γ subunits, where the central rotor subunit γ turns inside a stator cylinder made of alternately arranged α3β3 subunits using the energy derived from ATP hydrolysis. The rotor consists of an axle, a coiled coil of the amino- and carboxyl-terminal α-helices of γ, which deeply penetrates the stator cylinder, and a globular protrusion that juts out from the stator. Previous work has shown that, for a thermophilic F1, significant portions of the axle can be truncated and the motor still rotates a submicron sized bead duplex, indicating generation of up to half the wild-type (WT) torque. Here, we inquire if any specific interactions between the stator and the rest of the rotor are needed for the generation of a sizable torque. We truncated the protruding portion of the rotor and replaced part of the remaining axle residues such that every residue of the rotor has been deleted or replaced in this or previous truncation mutants. This protrusionless construct showed an unloaded rotary speed about a quarter of the WT, and generated one-third to one-half of the WT torque. No residue-specific interactions are needed for this much performance. F1 is so designed that the basic rotor-stator interactions for torque generation and control of catalysis rely solely upon the shape and size of the rotor at very low resolution. Additional tailored interactions augment the torque to allow ATP synthesis under physiological conditions.

  14. None of the Rotor Residues of F1-ATPase Are Essential for Torque Generation

    PubMed Central

    Chiwata, Ryohei; Kohori, Ayako; Kawakami, Tomonari; Shiroguchi, Katsuyuki; Furuike, Shou; Adachi, Kengo; Sutoh, Kazuo; Yoshida, Masasuke; Kinosita, Kazuhiko

    2014-01-01

    F1-ATPase is a powerful rotary molecular motor that can rotate an object several hundred times as large as the motor itself against the viscous friction of water. Forced reverse rotation has been shown to lead to ATP synthesis, implying that the mechanical work against the motor’s high torque can be converted into the chemical energy of ATP. The minimal composition of the motor protein is α3β3γ subunits, where the central rotor subunit γ turns inside a stator cylinder made of alternately arranged α3β3 subunits using the energy derived from ATP hydrolysis. The rotor consists of an axle, a coiled coil of the amino- and carboxyl-terminal α-helices of γ, which deeply penetrates the stator cylinder, and a globular protrusion that juts out from the stator. Previous work has shown that, for a thermophilic F1, significant portions of the axle can be truncated and the motor still rotates a submicron sized bead duplex, indicating generation of up to half the wild-type (WT) torque. Here, we inquire if any specific interactions between the stator and the rest of the rotor are needed for the generation of a sizable torque. We truncated the protruding portion of the rotor and replaced part of the remaining axle residues such that every residue of the rotor has been deleted or replaced in this or previous truncation mutants. This protrusionless construct showed an unloaded rotary speed about a quarter of the WT, and generated one-third to one-half of the WT torque. No residue-specific interactions are needed for this much performance. F1 is so designed that the basic rotor-stator interactions for torque generation and control of catalysis rely solely upon the shape and size of the rotor at very low resolution. Additional tailored interactions augment the torque to allow ATP synthesis under physiological conditions. PMID:24853745

  15. Mutational analysis of amino acid residues involved in catalytic activity of a family 18 chitinase from tulip bulbs.

    PubMed

    Suzukawa, Keisuke; Yamagami, Takeshi; Ohnuma, Takayuki; Hirakawa, Hideki; Kuhara, Satoru; Aso, Yoichi; Ishiguro, Masatsune

    2003-02-01

    We expressed chitinase-1 (TBC-1) from tulip bulbs (Tulipa bakeri) in E. coli cells and used site-directed mutagenesis to identify amino acid residues essential for catalytic activity. Mutations at Glu-125 and Trp-251 completely abolished enzyme activity, and activity decreased with mutations at Asp-123 and Trp-172 when glycolchitin was the substrate. Activity changed with the mutations of Trp-251 to one of several amino acids with side-chains of little hydrophobicity, suggesting that hydrophobic interaction of Trp-251 is important for the activity. Molecular dynamics (MD) simulation analysis with hevamine as the model compound showed that the distance between Asp-123 and Glu-125 was extended by mutation of Trp-251. Kinetic studies of Trp-251-mutated chitinases confirmed these various phenomena. The results suggested that Glu-125 and Trp-251 are essential for enzyme activity and that Trp-251 had a direct role in ligand binding.

  16. Aspartic Acid Residue D3 Critically Determines Cx50 Gap Junction Channel Transjunctional Voltage-Dependent Gating and Unitary Conductance

    PubMed Central

    Xin, Li; Nakagawa, So; Tsukihara, Tomitake; Bai, Donglin

    2012-01-01

    Previous studies have suggested that the aspartic acid residue (D) at the third position is critical in determining the voltage polarity of fast Vj-gating of Cx50 channels. To test whether another negatively charged residue (a glutamic acid residue, E) could fulfill the role of the D3 residue, we generated the mutant Cx50D3E. Vj-dependent gating properties of this mutant channel were characterized by double-patch-clamp recordings in N2A cells. Macroscopically, the D3E substitution reduced the residual conductance (Gmin) to near zero and outwardly shifted the half-inactivation voltage (V0), which is a result of both a reduced aggregate gating charge (z) and a reduced free-energy difference between the open and closed states. Single Cx50D3E gap junction channels showed reduced unitary conductance (γj) of the main open state, reduced open dwell time at ±40 mV, and absence of a long-lived substate. In contrast, a G8E substitution tested to compare the effects of the E residue at the third and eighth positions did not modify the Vj-dependent gating profile or γj. In summary, this study is the first that we know of to suggest that the D3 residue plays an essential role, in addition to serving as a negative-charge provider, as a critical determinant of the Vj-dependent gating sensitivity, open-closed stability, and unitary conductance of Cx50 gap junction channels. PMID:22404924

  17. 40 CFR 180.331 - 4-(2,4-Dichlorophenoxy) butyric acid; tolerances for residues.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... and conjugated, determined as the acid, in or on food commodities, as follows: Commodity Parts per... 40 Protection of Environment 24 2014-07-01 2014-07-01 false 4-(2,4-Dichlorophenoxy) butyric acid... Tolerances § 180.331 4-(2,4-Dichlorophenoxy) butyric acid; tolerances for residues. (a) General....

  18. 40 CFR 180.331 - 4-(2,4-Dichlorophenoxy) butyric acid; tolerances for residues.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... and conjugated, determined as the acid, in or on food commodities, as follows: Commodity Parts per... 40 Protection of Environment 25 2012-07-01 2012-07-01 false 4-(2,4-Dichlorophenoxy) butyric acid... Tolerances § 180.331 4-(2,4-Dichlorophenoxy) butyric acid; tolerances for residues. (a) General....

  19. 40 CFR 180.331 - 4-(2,4-Dichlorophenoxy) butyric acid; tolerances for residues.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... and conjugated, determined as the acid, in or on food commodities, as follows: Commodity Parts per... 40 Protection of Environment 25 2013-07-01 2013-07-01 false 4-(2,4-Dichlorophenoxy) butyric acid... Tolerances § 180.331 4-(2,4-Dichlorophenoxy) butyric acid; tolerances for residues. (a) General....

  20. 40 CFR 180.331 - 4-(2,4-Dichlorophenoxy) butyric acid; tolerances for residues.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... and conjugated, determined as the acid, in or on food commodities, as follows: Commodity Parts per... 40 Protection of Environment 23 2010-07-01 2010-07-01 false 4-(2,4-Dichlorophenoxy) butyric acid... Tolerances § 180.331 4-(2,4-Dichlorophenoxy) butyric acid; tolerances for residues. (a) General....

  1. Essential fatty acid intake and serum fatty acid composition among adolescent girls in central Mozambique.

    PubMed

    Freese, Riitta; Korkalo, Liisa; Vessby, Bengt; Tengblad, Siv; Vaara, Elina M; Hauta-alus, Helena; Selvester, Kerry; Mutanen, Marja

    2015-04-14

    Many African diets are low in fat but are currently changing because of nutrition transition. We studied fat and fatty acid (FA) intake and the essential fatty acid (EFA) status of adolescent girls (aged 14-19 years, n 262) in Zambezia Province, central Mozambique. A cross-sectional study was carried out in a city as well as in the towns and rural villages of a coastal and an inland district. Dietary intake and FA sources were studied in a 24 h dietary recall. FA compositions of cholesteryl esters and phospholipids of non-fasting serum samples were analysed by GLC. Fat intake was low (13-18 % of energy) in all areas. Coconut and palm oil were the main sources of fat, and soyabean oil and maize were the main sources of PUFA. Compared to Food and Agriculture Organization/WHO 2010 recommendations, intake of linoleic acid (LA, 18 : 2n-6) was inadequate in the coastal district, and intakes of n-3 PUFA were inadequate in all areas. FA compositions of serum lipids differed between areas. The proportions of LA tended to be highest in the city and lowest in the rural areas. The phospholipid mead (20 : 3n-9):arachidonic acid (20 : 4n-6) ratio did not indicate EFA insufficiency. LA proportions in phospholipids were low, but those of long-chain n-6 and n-3 PUFA were high in comparison with Western adolescents. To conclude, fat sources, FA intake and EFA status differed between adolescent girls living in different types of communities. Fat intake was low, but EFA insufficiency was not indicated.

  2. Hexameric RSF1010 helicase RepA: the structural and functional importance of single amino acid residues

    PubMed Central

    Ziegelin, Günter; Niedenzu, Timo; Lurz, Rudi; Saenger, Wolfram; Lanka, Erich

    2003-01-01

    In the known monoclinic crystals the 3-dimensional structure of the hexameric, replicative helicase RepA encoded by plasmid RSF1010 shows 6-fold rotational symmetry. In contrast, in the cubic crystal form at 2.55 Å resolution described here RepA has 3-fold symmetry and consists of a trimer of dimers. To study structure–function relationships, a series of repA deletion mutants and mutations yielding single amino acid exchanges were constructed and the respective gene products were analyzed in vivo and in vitro. Hexamerization of RepA occurs via the N-terminus and is required for NTP hydrolysis. The C-terminus is essential both for the interaction with the replication machinery and for the helicase activity. Functional analyses of RepA variants with single amino acid exchanges confirmed most of the predictions that were based on the published 3-dimensional structure. Of the five motifs conserved in family 4 helicases, all residues conserved in RepA and T7 gp4 helicases participate in DNA unwinding. Residues K42, E76, D77, D139 and H178, proposed to play key roles in catalyzing the hydrolysis of NTPs, are essential for RepA activity. Residue H178 of motif H3 couples nucleotide consumption to DNA strand separation. PMID:14530440

  3. Identification of essential histidine residues involved in heme binding and Hemozoin formation in heme detoxification protein from Plasmodium falciparum.

    PubMed

    Nakatani, Keisuke; Ishikawa, Haruto; Aono, Shigetoshi; Mizutani, Yasuhisa

    2014-08-20

    Malaria parasites digest hemoglobin within a food vacuole to supply amino acids, releasing the toxic product heme. During the detoxification, toxic free heme is converted into an insoluble crystalline form called hemozoin (Hz). Heme detoxification protein (HDP) in Plasmodium falciparum is one of the most potent of the hemozoin-producing enzymes. However, the reaction mechanisms of HDP are poorly understood. We identified the active site residues in HDP using a combination of Hz formation assay and spectroscopic characterization of mutant proteins. Replacement of the critical histidine residues His122, His172, His175, and His197 resulted in a reduction in the Hz formation activity to approximately 50% of the wild-type protein. Spectroscopic characterization of histidine-substituted mutants revealed that His122 binds heme and that His172 and His175 form a part of another heme-binding site. Our results show that the histidine residues could be present in the individual active sites and could be ligated to each heme. The interaction between heme and the histidine residues would serve as a molecular tether, allowing the proper positioning of two hemes to enable heme dimer formation. The heme dimer would act as a seed for the crystal growth of Hz in P. falciparum.

  4. Content of essential polyunsaturated fatty acids in three canned fish species.

    PubMed

    Gladyshev, Michail I; Sushchik, Nadezhda N; Makhutova, Olesia N; Kalachova, Galina S

    2009-05-01

    Three canned fish species--Pacific saury (Cololabis saira), Pacific herring (Clupea harengus) and Baltic sprat (Sprattus sprattus)--most common and popular in Russia, were analyzed for fatty acids. Special attention was paid to long-chain essential polyunsaturated fatty acids: eicosapentaenoic acid (20:5omega3) and docosahexaenoic acid (22:6omega3). Sums of eicosapentaenoic acid and docosahexaenoic acid in saury, herring and sprat were, on average, 2.42, 1.80 and 1.43 g/100 g product, respectively. Contents of these essential acids in all the canned fish species were found to be very high compared with many other fish reported in the available literature. All the canned fish appeared to be highly valuable products for human nutrition concerning the content of eicosapentaenoic and docosahexaenoic acids.

  5. Identification of ciliary neurotrophic factor (CNTF) residues essential for leukemia inhibitory factor receptor binding and generation of CNTF receptor antagonists.

    PubMed Central

    Di Marco, A; Gloaguen, I; Graziani, R; Paonessa, G; Saggio, I; Hudson, K R; Laufer, R

    1996-01-01

    Ciliary neurotrophic factor (CNTF) drives the sequential assembly of a receptor complex containing the ligand-specific alpha-receptor subunit (CNTFR alpha) and the signal transducers gp130 and leukemia inhibitory factor receptor-beta (LIFR). The D1 structural motif, located at the beginning of the D-helix of human CNTF, contains two amino acid residues, F152 and K155, which are conserved among all cytokines that signal through LIFR. The functional importance of these residues was assessed by alanine mutagenesis. Substitution of either F152 or K155 with alanine was found to specifically inhibit cytokine interaction with LIFR without affecting binding to CNTFR alpha or gp130. The resulting variants behaved as partial agonists with varying degrees of residual bioactivity in different cell-based assays. Simultaneous alanine substitution of both F152 and K155 totally abolished biological activity. Combining these mutations with amino acid substitutions in the D-helix, which enhance binding affinity for the CNTFR alpha, gave rise to a potent competitive CNTF receptor antagonist. This protein constitutes a new tool for studies of CNTF function in normal physiology and disease. Images Fig. 1 Fig. 6 PMID:8799186

  6. Teichuronic acid reducing terminal N-acetylglucosamine residue linked by phosphodiester to peptidoglycan of Micrococcus luteus

    SciTech Connect

    Gassner, G.T.; Dickie, J.P.; Hamerski, D.A.; Magnuson, J.K.; Anderson, J.S. )

    1990-05-01

    Teichuronic acid-peptidoglycan complex isolated from Micrococcus luteus cells by lysozyme digestion in osmotically stabilized medium was treated with mild acid to cleave the linkage joining teichuronic acid to peptidoglycan. This labile linkage was shown to be the phosphodiester which joins N-acetylglucosamine, the residue located at the reducing end of the teichuronic acid, through its anomeric hydroxyl group to a 6-phosphomuramic acid, a residue of the glycan strand of peptidoglycan. {sup 31}P nuclear magnetic resonance spectroscopy of the lysozyme digest of cell walls demonstrated the presence of a phosphodiester which was converted to a phosphomonoester by the conditions which released teichuronic acid from cell walls. Reduction of acid-liberated reducing end groups by NaB{sup 3}H{sub 4} followed by complete acid hydrolysis yielded ({sup 3}H) glucosaminitol from the true reducing end residue of teichuronic acid and ({sup 3}H)glucitol from the sites of fragmentation of teichuronic acid. The amount of N-acetylglucosamine detected was approximately stoichiometric with the amount of phosphate in the complex. Partial fragmentation of teichuronic acid provides an explanation of the previous erroneous identification of the reducing end residue.

  7. Determination of essential oils residues on zucchini fruits by GC-MS.

    PubMed

    Milano, Filomena; Donnarumma, Lucia

    2017-04-01

    In recent years, the use of essential oils (EOs) derived from aromatic plants as low-risk fungicides has increased considerably owing to their interest with organic growers and environmentally conscious consumers. The proposed method, based upon liquid-liquid extraction followed by gas chromatography-mass spectrometry analysis, is suitable for monitoring main components of EOs on zucchini fruits after protection treatments to control crop disease. The aim of this work is to find a rapid, simple and cheap procedure for screening analysis such as quality control of crops' edible portion.

  8. 40 CFR 180.155 - 1-Naphthaleneacetic acid; tolerances for residues.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... established for the combined residues of the plant growth regulator 1-naphthaleneacetic acid and its... ammonium, sodium, or potassium salts, ethyl ester, and acetamide in or on food commodities as...

  9. Phospho-N-Acetyl-Muramyl-Pentapeptide Translocase from Escherichia coli: Catalytic Role of Conserved Aspartic Acid Residues

    PubMed Central

    Lloyd, Adrian J.; Brandish, Philip E.; Gilbey, Andrea M.; Bugg, Timothy D. H.

    2004-01-01

    Phospho-N-acetyl-muramyl-pentapeptide translocase (translocase 1) catalyzes the first of a sequence of lipid-linked steps that ultimately assemble the peptidoglycan layer of the bacterial cell wall. This essential enzyme is the target of several natural product antibiotics and has recently been the focus of antimicrobial drug discovery programs. The catalytic mechanism of translocase 1 is believed to proceed via a covalent intermediate formed between phospho-N-acetyl-muramyl-pentapeptide and a nucleophilic amino acid residue. Amino acid sequence alignments of the translocase 1 family and members of the related transmembrane phosphosugar transferase superfamily revealed only three conserved residues that possess nucleophilic side chains: the aspartic acid residues D115, D116, and D267. Here we report the expression and partial purification of Escherichia coli translocase 1 as a C-terminal hexahistidine (C-His6) fusion protein. Three enzymes with the site-directed mutations D115N, D116N, and D267N were constructed, expressed, and purified as C-His6 fusions. Enzymatic analysis established that all three mutations eliminated translocase 1 activity, and this finding verified the essential role of these residues. By analogy with the structural environment of the double aspartate motif found in prenyl transferases, we propose a model whereby D115 and D116 chelate a magnesium ion that coordinates with the pyrophosphate bridge of the UDP-N-acetyl-muramyl-pentapeptide substrate and in which D267 therefore fulfills the role of the translocase 1 active-site nucleophile. PMID:14996806

  10. Fish oil prevents essential fatty acid deficiency and enhances growth: clinical and biochemical implications.

    PubMed

    Strijbosch, Robert A M; Lee, Sang; Arsenault, Danielle A; Andersson, Charlotte; Gura, Kathleen M; Bistrian, Bruce R; Puder, Mark

    2008-05-01

    Fish oil, a rich source of omega-3 fatty acids, has never been used as the sole source of lipid in clinical practice for fear of development of essential fatty acid deficiency, as it lacks the believed requisite levels of linoleic acid, an omega-6 fatty acid. The objectives of this study were to establish biochemical standards for fish oil as the sole fat and to test the hypothesis that fish oil contains adequate amounts of omega-6 fatty acids to prevent essential fatty acid deficiency. Forty mice were divided into 2 groups that were either pair fed or allowed to eat ad libitum. In each group, 4 subgroups of 5 mice were fed 1%, 5%, and 10% fish oil diets by weight or a control soybean diet for 9 weeks. Blood was collected at 4 time points, and fatty acid analysis was performed. Food intake and weight status were monitored. All groups but the pair-fed 1% fish oil group gained weight, and the 5% fish oil group showed the highest caloric efficiency in both pair-fed and ad libitum groups. Fatty acid profiles for the 1% fish oil group displayed clear essential fatty acid deficiency, 5% fish oil appeared marginal, and 10% and soybean oil diets were found to prevent essential fatty acid deficiency. Fish oil enhances growth through higher caloric efficiency. We established a total omega-6 fatty acid requirement of between 0.30% and 0.56% of dietary energy, approximately half of the conventionally believed 1% as linoleic acid. This can presumably be attributed to the fact that fish oil contains not only a small amount of linoleic acid, but also arachidonic acid, which has greater efficiency to meet omega-6 fatty acid requirements.

  11. Prediction of nucleic acid binding probability in proteins: a neighboring residue network based score.

    PubMed

    Miao, Zhichao; Westhof, Eric

    2015-06-23

    We describe a general binding score for predicting the nucleic acid binding probability in proteins. The score is directly derived from physicochemical and evolutionary features and integrates a residue neighboring network approach. Our process achieves stable and high accuracies on both DNA- and RNA-binding proteins and illustrates how the main driving forces for nucleic acid binding are common. Because of the effective integration of the synergetic effects of the network of neighboring residues and the fact that the prediction yields a hierarchical scoring on the protein surface, energy funnels for nucleic acid binding appear on protein surfaces, pointing to the dynamic process occurring in the binding of nucleic acids to proteins.

  12. Effect of temperature on iron leaching from bauxite residue by sulfuric acid.

    PubMed

    Liu, Zhi-Rong; Zeng, Kai; Zhao, Wei; Li, Ying

    2009-01-01

    Bauxite residue, as solid waste from alumina production, contains mainly hematite [Fe2O3]. Kinetic study of iron leaching of bauxite residue by diluted sulfuric acid at atmospheric pressure has been investigated. The results have been obtained as following: (i) Temperature play an important role in iron leaching from bauxite residue. Higher temperature is favor of Fe(III) leaching from bauxite residue. (ii) The leaching process is applicable to the intra-particle diffusion model and the apparent activation energy of model of leaching is found to be 17.32 kJ/mol.

  13. Entropy reduction in unfolded peptides (and proteins) due to conformational preferences of amino acid residues.

    PubMed

    Schweitzer-Stenner, Reinhard; Toal, Siobhan E

    2014-11-07

    As established by several groups over the last 20 years, amino acid residues in unfolded peptides and proteins do not exhibit the unspecific random distribution as assumed by the classical random coil model. Individual amino acid residues in small peptides were found to exhibit different conformational preferences. Here, we utilize recently obtained conformational distributions of guest amino acid residues in GxG peptides to estimate their conformational entropy, which we find to be significantly lower than the entropy of an assumed random coil like distribution. Only at high temperature do backbone entropies approach random coil like values. We utilized the obtained backbone entropies of the investigated amino acid residues to estimate the loss of conformational entropy caused by a coil → helix transition and identified two subsets of amino acid residues for which the thus calculated entropy losses correlate well with the respective Gibbs energy of helix formation obtained for alanine based host-guest systems. Calculated and experimentally derived entropic losses were found to be in good agreement. For most of the amino acid residues investigated entropic losses derived from our GxG distributions correlate very well with corresponding values recently obtained from MD simulations biased by conformational propensities derived from truncated coil libraries. Both, conformational entropy and the entropy of solvation exhibit a strong, residue specific temperature dependence, which can be expected to substantially affect the stability of unfolded states. Altogether, our results provide strong evidence for the notion that conformational preferences of amino acid residues matter with regard to the thermodynamics of peptide and protein folding.

  14. Identification of amino acids essential for DNA binding and dimerization in p67SRF: implications for a novel DNA-binding motif.

    PubMed Central

    Sharrocks, A D; Gille, H; Shaw, P E

    1993-01-01

    The serum response factor (p67SRF) binds to a palindromic sequence in the c-fos serum response element (SRE). A second protein, p62TCF binds in conjunction with p67SRF to form a ternary complex, and it is through this complex that growth factor-induced transcriptional activation of c-fos is thought to take place. A 90-amino-acid peptide, coreSRF, is capable for dimerizing, binding DNA, and recruiting p62TCF. By using extensive site-directed mutagenesis we have investigated the role of individual coreSRF amino acids in DNA binding. Mutant phenotypes were defined by gel retardation and cross-linking analyses. Our results have identified residues essential for either DNA binding or dimerization. Three essential basic amino acids whose conservative mutation severely reduced DNA binding were identified. Evidence which is consistent with these residues being on the face of a DNA binding alpha-helix is presented. A phenylalanine residue and a hexameric hydrophobic box are identified as essential for dimerization. The amino acid phasing is consistent with the dimerization interface being presented as a continuous region on a beta-strand. A putative second alpha-helix acts as a linker between these two regions. This study indicates that p67SRF is a member of a protein family which, in common with many DNA binding proteins, utilize an alpha-helix for DNA binding. However, this alpha-helix is contained within a novel domain structure. Images PMID:8417320

  15. Core Amino Acid Residues in the Morphology-Regulating Protein, Mms6, for Intracellular Magnetite Biomineralization

    PubMed Central

    Yamagishi, Ayana; Narumiya, Kaori; Tanaka, Masayoshi; Matsunaga, Tadashi; Arakaki, Atsushi

    2016-01-01

    Living organisms produce finely tuned biomineral architectures with the aid of biomineral-associated proteins. The functional amino acid residues in these proteins have been previously identified using in vitro and in silico experimentation in different biomineralization systems. However, the investigation in living organisms is limited owing to the difficulty in establishing appropriate genetic techniques. Mms6 protein, isolated from the surface of magnetite crystals synthesized in magnetotactic bacteria, was shown to play a key role in the regulation of crystal morphology. In this study, we have demonstrated a defect in the specific region or substituted acidic amino acid residues in the Mms6 protein for observing their effect on magnetite biomineralization in vivo. Analysis of the gene deletion mutants and transformants of Magnetospirillum magneticum AMB-1 expressing partially truncated Mms6 protein revealed that deletions in the N-terminal or C-terminal regions disrupted proper protein localization to the magnetite surface, resulting in a change in the crystal morphology. Moreover, single amino acid substitutions at Asp123, Glu124, or Glu125 in the C-terminal region of Mms6 clearly indicated that these amino acid residues had a direct impact on magnetite crystal morphology. Thus, these consecutive acidic amino acid residues were found to be core residues regulating magnetite crystal morphology. PMID:27759096

  16. Effects of advanced oxidation pretreatment on residual aluminum control in high humic acid water purification.

    PubMed

    Wang, Wendong; Li, Hua; Ding, Zhenzhen; Wang, Xiaochang

    2011-01-01

    Due to the formation of disinfection by-products and high concentrations of Al residue in drinking water purification, humic substances are a major component of organic matter in natural waters and have therefore received a great deal of attention in recent years. We investigated the effects of advanced oxidation pretreatment methods usually applied for removing dissolved organic matters on residual Al control. Results showed that the presence of humic acid increased residual Al concentration notably. With 15 mg/L of humic acid in raw water, the concentrations of soluble aluminum and total aluminum in the treated water were close to the quantity of Al addition. After increasing coagulant dosage from 12 to 120 mg/L, the total-Al in the treated water was controlled to below 0.2 mg/L. Purification systems with ozonation, chlorination, or potassium permanganate oxidation pretreatment units had little effects on residual Al control; while UV radiation decreased Al concentration notably. Combined with ozonation, the effects of UV radiation were enhanced. Optimal dosages were 0.5 mg O3/mg C and 3 hr for raw water with 15 mg/L of humic acid. Under UV light radiation, the combined forces or bonds that existed among humic acid molecules were destroyed; adsorption sites increased positively with radiation time, which promoted adsorption of humic acid onto polymeric aluminum and Al(OH)3(s). This work provides a new solution for humic acid coagulation and residual Al control for raw water with humic acid purification.

  17. Reversible phenotypic modulation induced by deprivation of exogenous essential fatty acids.

    PubMed

    Laposata, M; Minda, M; Capriotti, A M; Hartman, E J; Furth, E E; Iozzo, R V

    1988-12-01

    Essential fatty acid deficiency, produced by deprivation of omega-6 and omega-3 fatty acids, is a condition characterized by renal disease, dermatitis, and infertility. Although many of the biochemical aspects of this disorder have been investigated, little is known about the ultrastructural changes induced by essential fatty acid deficiency. Using a unique fatty acid-deficient cell line (EFD-1), which demonstrates the in vivo fatty acid changes of essential fatty acid deficiency, and the prostaglandin E2-producing mouse fibrosarcoma line from which it was derived (HSDM1C1), we correlated ultrastructural and biochemical changes induced by prolonged deprivation of all exogenous lipids and subsequent repletion of selected essential fatty acids. We found that in cells deprived of all exogenous lipids, there was dilation of rough endoplasmic reticulum and an associated defect in protein secretion; these changes were specifically reversed by arachidonate. There was also an accumulation of secondary lysosomes containing degraded membranes in these cells with an associated increase in phospholipids relative to parent HSDM1C1 cells. Cytoplasmic lipid bodies present in parent cells disappeared, with an associated decrease in triacylglycerol. After just 2 days in lipid-free medium, all these changes were apparent, and prostaglandin E2 production was markedly impaired despite normal amounts of cellular arachidonate. Incubation of EFD-1 cells with arachidonate, the major prostaglandin precursor fatty acid, induced a reversion to the HSDM1C1 phenotype, whereas other fatty acids were totally ineffective. These results indicate changes in fatty acid metabolism in essential fatty acid deficiency are associated with marked alterations in ultrastructure and secretion of protein from cells.

  18. Essential Fatty Acids and Attention-Deficit-Hyperactivity Disorder: A Systematic Review

    ERIC Educational Resources Information Center

    Raz, Raanan; Gabis, Lidia

    2009-01-01

    Aim: Essential fatty acids (EFAs), also known as omega-3 and omega-6 fatty acids, have been claimed to have beneficial effects as a treatment for attention-deficit-hyperactivity disorder (ADHD). Animal experiments have provided information about the role of EFA in the brain, and several mechanisms of EFA activity are well known. The current review…

  19. Esterification of essential and non-essential fatty acids into distinct lipid classes in ruminant and non-ruminant tissues.

    PubMed

    Caldari-Torres, Cristina; McGilliard, Michael L; Corl, Benjamin A

    2016-10-01

    Extensive microbial biohydrogenation of polyunsaturated fatty acids (PUFA) in the rumen reduces the essential fatty acids (EFA) available for absorption in ruminant animals, but there is no published documentation of ruminants developing EFA deficiency. In ruminants, most circulating PUFA are found in the phospholipid (PL) and cholesteryl ester lipid classes that have slow turn-over compared to other lipid classes. The objective of this experiment was to measure fatty acid esterification patterns of the non-EFA palmitic (16:0) and oleic acid (18:1), and the EFA linoleic (18:2) and linolenic acid (18:3) in small intestine, liver, and muscle tissue of cows and pigs to identify tissues participating in sequestration of these FA in less metabolically active lipid classes in ruminants. Bovine and porcine small intestine, liver, and muscle explants were prepared and incubated in media containing radiolabeled 16:0, 18:1, 18:2, or 18:3 to measure esterification of fatty acids into PL and TG. Neither bovine nor porcine small intestine explants preferentially incorporated non-EFA compared to EFA into PL vs TG. Bovine liver explants esterified a larger proportion of EFA than non-EFA into PL compared to TG, while incorporation was similar among the FA tested in porcine liver explants. Bovine muscle explants showed preferential incorporation of EFA into PL rather than TG. Results show that bovine and porcine liver and muscle esterify EFA and non-EFA differently and that the conservation of EFA in ruminants is a result of preferential incorporation of EFA into PL mediated by bovine liver and muscle, but not the small intestine.

  20. Protective Effect of Ocimum basilicum Essential Oil Against Acetic Acid-Induced Colitis in Rats.

    PubMed

    Rashidian, Amir; Roohi, Parnia; Mehrzadi, Saeed; Ghannadi, Ali Reza; Minaiyan, Mohsen

    2016-10-01

    Ocimum basilicum L has been traditionally used for the treatment of inflammatory bowel disease in Iran. This study investigates the ameliorative effect of Ocimum basilicum essential oil on an acetic acid-induced colitis model in rats. Ocimum basilicum essential oil with 2 doses (200 and 400 μL/kg) significantly ameliorated wet weight/length ratio of colonic tissue compared to the control group. Higher doses of essential oil (200 and 400 μL/kg) significantly reduced ulcer severity, ulcer area, and ulcer index. On the other hand, histological examination revealed the diminution of total colitis index as a marker for inflammatory cell infiltration in the colonic segments of rats treated with Ocimum basilicum essential oil (200 and 400 μL/kg). The increased level of myeloperoxidase was significantly decreased after the treatment with the essential oil (200 and 400 μL/kg). These results suggest that Ocimum basilicum exhibits protective effect against acetic acid-induced colitis.

  1. A new α-galactosidase from symbiotic Flavobacterium sp. TN17 reveals four residues essential for α-galactosidase activity of gastrointestinal bacteria.

    PubMed

    Zhou, Junpei; Shi, Pengjun; Huang, Huoqing; Cao, Yanan; Meng, Kun; Yang, Peilong; Zhang, Rui; Chen, Xiaoyan; Yao, Bin

    2010-12-01

    The α-galactosidase gene, galA17, was cloned from Flavobacterium sp. TN17, a symbiotic bacterium isolated from the gut of Batocera horsfieldi larvae. The 2,205-bp full-length gene encodes a 734-residue polypeptide (GalA17) containing a putative 28-residue signal peptide and a catalytic domain belonging to glycosyl hydrolase family 36 (GH 36). The deduced amino acid sequence of galA17 was most similar to a putative α-galactosidase from Pedobacter sp. BAL39 (EDM38577; 66.6% identity) and a characterized α-galactosidase from Carnobacterium piscicola BA (AAL27305; 30.1%). Phylogenetic analysis revealed that GalA17 was similar to GH 36 α-galactosidases from symbiotic bacteria sharing two putative catalytic motifs, KWD and SDXXDXXXR, in which D480, S548, D549, and R556 were essential for α-galactosidase activity based on site-directed mutagenesis. Purified recombinant GalA17 showed apparent optimal activity at pH 5.5 and 45°C; exhibited strong resistance to digestion by trypsin, α-chymotrypsin, collagenase, and proteinase K; and efficiently hydrolyzed several synthetic and natural substrates (p-nitrophenyl-α-D-galactopyranoside, stachyose, melibiose, raffinose, soybean meal, locust bean gum, and guar gum).

  2. On the distribution of amino acid residues in transmembrane alpha-helix bundles.

    PubMed Central

    Samatey, F A; Xu, C; Popot, J L

    1995-01-01

    The periodic distribution of residues in the sequence of 469 putative transmembrane alpha-helices from eukaryotic plasma membrane polytopic proteins has been analyzed with correlation matrices. The method does not involve any a priori assumption about the secondary structure of the segments or about the physicochemical properties of individual amino acid residues. Maximal correlation is observed at 3.6 residues per period, characteristic of alpha-helices. A scale extracted from the data describes the propensity of the various residues to lie on the same or on opposite helix faces. The most polar face of transmembrane helices, presumably that buried in the protein core, shows a strong enrichment in aromatic residues, while residues likely to face the fatty acyl chains of lipids are largely aliphatic. PMID:7753846

  3. Two Cys residues essential for von Willebrand factor multimer assembly in the Golgi.

    PubMed

    Purvis, Angie R; Gross, Julia; Dang, Luke T; Huang, Ren-Huai; Kapadia, Milan; Townsend, R Reid; Sadler, J Evan

    2007-10-02

    Von Willebrand factor (VWF) dimerizes through C-terminal CK domains, and VWF dimers assemble into multimers in the Golgi by forming intersubunit disulfide bonds between D3 domains. This unusual oxidoreductase reaction requires the VWF propeptide (domains D1D2), which acts as an endogenous pH-dependent chaperone. The cysteines involved in multimer assembly were characterized by using a VWF construct that encodes the N-terminal D1D2D'D3 domains. Modification with thiol-specific reagents demonstrated that secreted D'D3 monomer contained reduced Cys, whereas D'D3 dimer and propeptide did not. Reduced Cys in the D'D3 monomer were alkylated with N-ethylmaleimide and analyzed by mass spectrometry. All 52 Cys within the D'D3 region were observed, and only Cys(1099) and Cys(1142) were modified by N-ethylmaleimide. When introduced into the D1D2D'D3 construct, the mutation C1099A or C1142A markedly impaired the formation of D'D3 dimers, and the double mutation prevented dimerization. In full-length VWF, the mutations C1099A and C1099A/C1142A prevented multimer assembly; the mutation C1142A allowed the formation of almost exclusively dimers, with few tetramers and no multimers larger than hexamers. Therefore, Cys(1099) and Cys(1142) are essential for the oxidoreductase mechanism of VWF multimerization. Cys(1142) is reported to form a Cys(1142)-Cys(1142) intersubunit bond, suggesting that Cys(1099) also participates in a Cys(1099)-Cys(1099) disulfide bond between D3 domains. This arrangement of intersubunit disulfide bonds implies that the dimeric N-terminal D'D3 domains of VWF subunits align in a parallel orientation within VWF multimers.

  4. Essential fatty acids in the treatment of dry eye syndrome: A myth or reality?

    PubMed Central

    Al Mahmood, Ammar M.; Al-Swailem, Samar A.

    2014-01-01

    Dry eye is a common condition that can severely impair the quality of life. Systemic and topical omega-3 fatty acids and omega-6 fatty acids have been used as treatment for patients with dry eye disease and showed promising results. Further multicenter randomized controlled trials are required in order to establish a standardized protocol for the treatment of dry eye syndrome with those essential fatty acids. PMID:25278796

  5. Site-Directed Mutagenesis of HgcA and HgcB Reveals Amino Acid Residues Important for Mercury Methylation

    PubMed Central

    Smith, Steven D.; Bridou, Romain; Johs, Alexander; Parks, Jerry M.; Elias, Dwayne A.; Hurt, Richard A.; Brown, Steven D.; Podar, Mircea

    2015-01-01

    Methylmercury is a potent neurotoxin that is produced by anaerobic microorganisms from inorganic mercury by a recently discovered pathway. A two-gene cluster, consisting of hgcA and hgcB, encodes two of the proteins essential for this activity. hgcA encodes a corrinoid protein with a strictly conserved cysteine proposed to be the ligand for cobalt in the corrinoid cofactor, whereas hgcB encodes a ferredoxin-like protein thought to be an electron donor to HgcA. Deletion of either gene eliminates mercury methylation by the methylator Desulfovibrio desulfuricans ND132. Here, site-directed mutants of HgcA and HgcB were constructed to determine amino acid residues essential for mercury methylation. Mutations of the strictly conserved residue Cys93 in HgcA, the proposed ligand for the corrinoid cobalt, to Ala or Thr completely abolished the methylation capacity, but a His substitution produced measurable methylmercury. Mutations of conserved amino acids near Cys93 had various impacts on the methylation capacity but showed that the structure of the putative “cap helix” region harboring Cys93 is crucial for methylation function. In the ferredoxin-like protein HgcB, only one of two conserved cysteines found at the C terminus was necessary for methylation, but either cysteine sufficed. An additional, strictly conserved cysteine, Cys73, was also determined to be essential for methylation. This study supports the previously predicted importance of Cys93 in HgcA for methylation of mercury and reveals additional residues in HgcA and HgcB that facilitate the production of this neurotoxin. PMID:25724962

  6. Site-Directed Mutagenesis of HgcA and HgcB Reveals Amino Acid Residues Important for Mercury Methylation

    DOE PAGES

    Smith, Steven D.; Bridou, Romain; Johs, Alexander; ...

    2015-02-27

    Methylmercury is a potent neurotoxin that is produced by anaerobic microorganisms from inorganic mercury by a recently discovered pathway. A two-gene cluster, consisting of hgcA and hgcB, encodes two of the proteins essential for this activity. hgcA encodes a corrinoid protein with a strictly conserved cysteine proposed to be the ligand for cobalt in the corrinoid cofactor, whereas hgcB encodes a ferredoxin-like protein thought to be an electron donor to HgcA. Deletion of either gene eliminates mercury methylation by the methylator Desulfovibrio desulfuricans ND132. Here, site-directed mutants of HgcA and HgcB were constructed to determine amino acid residues essential formore » mercury methylation. Mutations of the strictly conserved residue Cys93 in HgcA, the proposed ligand for the corrinoid cobalt, to Ala or Thr completely abolished the methylation capacity, but a His substitution produced measurable methylmercury. Mutations of conserved amino acids near Cys93 had various impacts on the methylation capacity but showed that the structure of the putative “cap helix” region harboring Cys93 is crucial for methylation function. In the ferredoxin-like protein HgcB, only one of two conserved cysteines found at the C terminus was necessary for methylation, but either cysteine sufficed. An additional, strictly conserved cysteine, Cys73, was also determined to be essential for methylation. Ultimately, this study supports the previously predicted importance of Cys93 in HgcA for methylation of mercury and reveals additional residues in HgcA and HgcB that facilitate the production of this neurotoxin.« less

  7. Site-Directed Mutagenesis of HgcA and HgcB Reveals Amino Acid Residues Important for Mercury Methylation

    SciTech Connect

    Smith, Steven D.; Bridou, Romain; Johs, Alexander; Parks, Jerry M.; Elias, Dwayne A.; Hurt, Richard A.; Brown, Steven D.; Podar, Mircea; Wall, Judy D.

    2015-02-27

    Methylmercury is a potent neurotoxin that is produced by anaerobic microorganisms from inorganic mercury by a recently discovered pathway. A two-gene cluster, consisting of hgcA and hgcB, encodes two of the proteins essential for this activity. hgcA encodes a corrinoid protein with a strictly conserved cysteine proposed to be the ligand for cobalt in the corrinoid cofactor, whereas hgcB encodes a ferredoxin-like protein thought to be an electron donor to HgcA. Deletion of either gene eliminates mercury methylation by the methylator Desulfovibrio desulfuricans ND132. Here, site-directed mutants of HgcA and HgcB were constructed to determine amino acid residues essential for mercury methylation. Mutations of the strictly conserved residue Cys93 in HgcA, the proposed ligand for the corrinoid cobalt, to Ala or Thr completely abolished the methylation capacity, but a His substitution produced measurable methylmercury. Mutations of conserved amino acids near Cys93 had various impacts on the methylation capacity but showed that the structure of the putative “cap helix” region harboring Cys93 is crucial for methylation function. In the ferredoxin-like protein HgcB, only one of two conserved cysteines found at the C terminus was necessary for methylation, but either cysteine sufficed. An additional, strictly conserved cysteine, Cys73, was also determined to be essential for methylation. Ultimately, this study supports the previously predicted importance of Cys93 in HgcA for methylation of mercury and reveals additional residues in HgcA and HgcB that facilitate the production of this neurotoxin.

  8. Cysteine residues of the porcine reproductive and respiratory syndrome virus ORF5a protein are not essential for virus viability.

    PubMed

    Sun, Lichang; Zhou, Yan; Liu, Runxia; Li, Yanhua; Gao, Fei; Wang, Xiaomin; Fan, Hongjie; Yuan, Shishan; Wei, Zuzhang; Tong, Guangzhi

    2015-02-02

    ORF5a protein was recently identified as a novel structural protein in porcine reproductive and respiratory syndrome virus (PRRSV). The ORF5a protein possesses two cysteines at positions 29 and 30 that are highly conserved among type 2 PRRSV. In this study, the significance of the ORF5a protein cysteine residues on virus replication was determined based on a type 2 PRRSV cDNA clone (pAJXM). Each cysteine was substituted by serine or glycine and the mutations were introduced into pAJXM. We found that the replacement of cysteine to glycine at position 30 was lethal for virus viability, but all serine mutant clones produced infectious progeny viruses. This data indicated that cysteine residues in the ORF5a protein were not essential for replication of type 2 PRRSV. The bimolecular fluorescence complementation (BiFC) and Co-immunoprecipitation (Co-IP) assay were used to study ORF5a protein interacted with other enveloped proteins. These results showed that ORF5a protein interacted non-covalently with itself and interacted with GP4 and 2b protein. The replacement of cysteine to glycine at position 30 affected the ORF5a protein interacted non-covalently with itself, which may account for the lethal phenotype of mutants carrying substitution of cysteine to glycine at position 30.

  9. Solvent accessibility, residue charge and residue volume, the three ingredients of a robust amino acid substitution matrix.

    PubMed

    Goodarzi, Hani; Katanforoush, Ali; Torabi, Noorossadat; Najafabadi, Hamed Shateri

    2007-04-21

    Cost measure matrices or different amino acid indices have been widely used for studies in many fields of biology. One major criticism of these studies might be based on the unavailability of an unbiased and yet effective amino acid substitution matrix. Throughout this study we have devised a cost measure matrix based on the solvent accessibility, residue charge, and residue volume indices. Performed analyses on this novel substitution matrix (i.e. solvent accessibility charge volume (SCV) matrix) support the uncontaminated nature of this matrix regarding the genetic code. Although highly similar to a number of previously available cost measure matrices, the SCV matrix results in a more significant optimality in the error-buffering capacity of the genetic code when compared to many other amino acid substitution matrices. Besides, a method to compare an SCV-based scoring matrix with a number of widely used matrices has been devised, the results of which highlights the robustness of this matrix in protein family discrimination.

  10. Antioxidant activities of rosemary (Rosmarinus Officinalis L.) extract, blackseed (Nigella sativa L.) essential oil, carnosic acid, rosmarinic acid and sesamol.

    PubMed

    Erkan, Naciye; Ayranci, Guler; Ayranci, Erol

    2008-09-01

    Antioxidant activities of three pure compounds: carnosic acid, rosmarinic acid and sesamol, as well as two plant extracts: rosemary extract and blackseed essential oil, were examined by applying DPPH and ABTS(+) radical-scavenging assays and the ferric thiocyanate test. All three test methods proved that rosemary extract had a higher antioxidant activity than blackseed essential oil. The order of antioxidant activity of pure compounds showed variations in different tests. This was attributed to structural factors of individual compounds. Phenolic contents of blackseed essential oil and rosemary extract were also determined. Rosemary extract was found to have a higher phenolic content than blackseed essential oil. This fact was utilised in explaining the higher antioxidant activity of rosemary extract.

  11. Optimization of acid hydrolysis from the hemicellulosic fraction of Eucalyptus grandis residue using response surface methodology.

    PubMed

    Canettieri, Eliana Vieira; de Moraes Rocha, George Jackson; de Carvalho, João Andrade; de Almeida e Silva, João Batista

    2007-01-01

    Biotechnological conversion of biomass into fuels and chemicals requires hydrolysis of the polysaccharide fraction into monomeric sugars. Hydrolysis can be performed enzymatically and with dilute or concentrate mineral acids. The present study used dilute sulfuric acid as a catalyst for hydrolysis of Eucalyptus grandis residue. The purpose of this paper was to optimize the hydrolysis process in a 1.4 l pilot-scale reactor and investigate the effects of the acid concentration, temperature and residue/acid solution ratio on the hemicellulose removal and consequently on the production of sugars (xylose, glucose and arabinose) as well as on the formation of by-products (furfural, 5-hydroxymethylfurfural and acetic acid). This study was based on a model composition corresponding to a 2(3) orthogonal factorial design and employed the response surface methodology (RSM) to optimize the hydrolysis conditions, aiming to attain maximum xylose extraction from hemicellulose of residue. The considered optimum conditions were: H(2)SO(4) concentration of 0.65%, temperature of 157 degrees C and residue/acid solution ratio of 1/8.6 with a reaction time of 20 min. Under these conditions, 79.6% of the total xylose was removed and the hydrolysate contained 1.65 g/l glucose, 13.65 g/l xylose, 1.55 g/l arabinose, 3.10 g/l acetic acid, 1.23 g/l furfural and 0.20 g/l 5-hydroxymethylfurfural.

  12. Essential dietary amino acids for growth of larvae of the yellow mealworm, Tenebrio molitor L.

    PubMed

    Davis, G R

    1975-08-01

    Larvae of the yellow mealworm, Tenebrio molitor L., have been used to evaluate nutritional quality of proteins and protein isolates. However, such investigations have been complicated by lack of knowledge of dietary requirements of the larvae. To determine essential dietary amino acids for growth of Tenebrio molitor, single amino acids were deleted from the amino acid mixture of the diet. Diets were maintained isonitrogenous with supplementary glycine and, in the case of deleted glycine, with glutamic acid. Growth, as measured by gain in weight, and survival were observed over a 4-week period at 27 plus or minus 0.25 degrees and 65 plus or minus 5% relative humidity. The results indicate that larvae of Tenebrio molitor require a dietary source of the same 10 amino acids essential for growth in rats, other vertebrates, and some protozoa. They also showed that serine, tyrosine, glutamic acid, and possibly glycine were dispensable for growth in this insect. Alanine, cystine, proline, and aspartic acid appeared semidispensable. Survival over the 4-week experimental period was unaffected by deleting amino acids from the diet. The results are discussed in relation to amino acid requirements of other insects and to suggested improvement of the diet of the present investigation.

  13. Hepatic Fasting-Induced PPARα Activity Does Not Depend on Essential Fatty Acids.

    PubMed

    Polizzi, Arnaud; Fouché, Edwin; Ducheix, Simon; Lasserre, Frédéric; Marmugi, Alice P; Mselli-Lakhal, Laila; Loiseau, Nicolas; Wahli, Walter; Guillou, Hervé; Montagner, Alexandra

    2016-09-24

    The liver plays a central role in the regulation of fatty acid metabolism, which is highly sensitive to transcriptional responses to nutrients and hormones. Transcription factors involved in this process include nuclear hormone receptors. One such receptor, PPARα, which is highly expressed in the liver and activated by a variety of fatty acids, is a critical regulator of hepatic fatty acid catabolism during fasting. The present study compared the influence of dietary fatty acids and fasting on hepatic PPARα-dependent responses. Pparα(-/-) male mice and their wild-type controls were fed diets containing different fatty acids for 10 weeks prior to being subjected to fasting or normal feeding. In line with the role of PPARα in sensing dietary fatty acids, changes in chronic dietary fat consumption influenced liver damage during fasting. The changes were particularly marked in mice fed diets lacking essential fatty acids. However, fasting, rather than specific dietary fatty acids, induced acute PPARα activity in the liver. Taken together, the data imply that the potent signalling involved in triggering PPARα activity during fasting does not rely on essential fatty acid-derived ligand.

  14. The N-terminal portion of domain E of retinoic acid receptors alpha and beta is essential for the recognition of retinoic acid and various analogs.

    PubMed

    Ostrowski, J; Hammer, L; Roalsvig, T; Pokornowski, K; Reczek, P R

    1995-03-14

    Utilizing a strategy involving domain exchange between retinoic acid receptors alpha and beta (RAR alpha and RAR beta) and monitoring the transcriptional activity of the resulting chimeric receptors with receptor-selective retinoids, we identified a 70-aa region within the N-terminal portion of the RAR alpha and -beta domain E which is important for an RAR alpha- or RAR beta-specific response. Two amino acid residues within this region, serine-232 (S232) and threonine-239 (T239) in RAR alpha and the corresponding alanine-225 (A225) and isoleucine-232 (I232) in RAR beta, were found to be essential for this effect. In addition, binding studies using the chimeric receptors expressed in Escherichia coli showed that the N-terminal portion of domain E was also important for the characteristic binding profile of t-RA and various retinoids with RAR alpha or RAR beta. Structural predictions of the primary amino acid sequence in this region indicate the presence of an amphipathic helix-turn-helix structure with five hydrophobic amino acids that resemble a leucine zipper motif. The amino acid residues identified by domain swapping, S232 and T239 in RAR alpha and A225 and I232 in RAR beta, were found within the hydrophobic face of an alpha-helix in close proximity to this zipper motif, suggesting that the ligand may interact with the receptor in the region adjacent to a surface involved in protein-protein interactions. This finding may link ligand binding to other processes important for transcriptional activation.

  15. The N-terminal portion of domain E of retinoic acid receptors alpha and beta is essential for the recognition of retinoic acid and various analogs.

    PubMed Central

    Ostrowski, J; Hammer, L; Roalsvig, T; Pokornowski, K; Reczek, P R

    1995-01-01

    Utilizing a strategy involving domain exchange between retinoic acid receptors alpha and beta (RAR alpha and RAR beta) and monitoring the transcriptional activity of the resulting chimeric receptors with receptor-selective retinoids, we identified a 70-aa region within the N-terminal portion of the RAR alpha and -beta domain E which is important for an RAR alpha- or RAR beta-specific response. Two amino acid residues within this region, serine-232 (S232) and threonine-239 (T239) in RAR alpha and the corresponding alanine-225 (A225) and isoleucine-232 (I232) in RAR beta, were found to be essential for this effect. In addition, binding studies using the chimeric receptors expressed in Escherichia coli showed that the N-terminal portion of domain E was also important for the characteristic binding profile of t-RA and various retinoids with RAR alpha or RAR beta. Structural predictions of the primary amino acid sequence in this region indicate the presence of an amphipathic helix-turn-helix structure with five hydrophobic amino acids that resemble a leucine zipper motif. The amino acid residues identified by domain swapping, S232 and T239 in RAR alpha and A225 and I232 in RAR beta, were found within the hydrophobic face of an alpha-helix in close proximity to this zipper motif, suggesting that the ligand may interact with the receptor in the region adjacent to a surface involved in protein-protein interactions. This finding may link ligand binding to other processes important for transcriptional activation. PMID:7892182

  16. Protein and Essential Amino Acids to Protect Musculoskeletal Health during Spaceflight: Evidence of a Paradox?

    PubMed Central

    Hackney, Kyle J.; English, Kirk L.

    2014-01-01

    Long-duration spaceflight results in muscle atrophy and a loss of bone mineral density. In skeletal muscle tissue, acute exercise and protein (e.g., essential amino acids) stimulate anabolic pathways (e.g., muscle protein synthesis) both independently and synergistically to maintain neutral or positive net muscle protein balance. Protein intake in space is recommended to be 12%–15% of total energy intake (≤1.4 g∙kg−1∙day−1) and spaceflight is associated with reduced energy intake (~20%), which enhances muscle catabolism. Increasing protein intake to 1.5–2.0 g∙kg−1∙day−1 may be beneficial for skeletal muscle tissue and could be accomplished with essential amino acid supplementation. However, increased consumption of sulfur-containing amino acids is associated with increased bone resorption, which creates a dilemma for musculoskeletal countermeasures, whereby optimizing skeletal muscle parameters via essential amino acid supplementation may worsen bone outcomes. To protect both muscle and bone health, future unloading studies should evaluate increased protein intake via non-sulfur containing essential amino acids or leucine in combination with exercise countermeasures and the concomitant influence of reduced energy intake. PMID:25370374

  17. 75 FR 1773 - Notice of Receipt of a Pesticide Petition Filed for Residues of Polymeric Polyhydroxy Acid in or...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-01-13

    ... AGENCY Notice of Receipt of a Pesticide Petition Filed for Residues of Polymeric Polyhydroxy Acid in or... establishment of a regulation for residues of the plant growth regulator, polymeric polyhydroxy acid, in or on... polymeric polyhydroxy acid in or on all food commodities. EPA has determined that the pesticide...

  18. Stage of harvest and polyunsaturated essential fatty acid concentrations in purslane (Portulaca oleraceae) leaves.

    PubMed

    Palaniswamy, U R; McAvoy, R J; Bible, B B

    2001-07-01

    Purslane is a nutritious vegetable crop rich in the polyunsaturated essential fatty acids (PUEFA) alpha-linolenic acid (LNA) and linoleic acid (LA), which are essential for normal human growth, health promotion, and disease prevention. Total lipids and fatty acid concentrations at three stages of harvest (6-, 10-, and 14-true-leaf stages) were examined in a cultivated variety of purslane (Portulaca oleraceae L. var. sativa). The 14-true-leaf stage of growth was found to be ideal for harvest because at this stage the leaf area, shoot fresh weight, shoot dry weight, and PUEFA concentrations per gram of leaf fresh weight were higher (P < or = 0.05) than at the 6- and 10-true-leaf stages of growth. The LNA to LA ratio was also highest at the 14-true-leaf stage.

  19. In vitro susceptibility of Brachyspira hyodysenteriae to organic acids and essential oil components

    PubMed Central

    VANDE MAELE, Lien; HEYNDRICKX, Marc; MAES, Dominiek; DE PAUW, Nele; MAHU, Maxime; VERLINDEN, Marc; HAESEBROUCK, Freddy; MARTEL, An; PASMANS, Frank; BOYEN, Filip

    2015-01-01

    The antibacterial potential of organic acids and essential oil components against Brachyspira hyodysenteriae, the causative pathogen of swine dysentery, was evaluated. Minimum inhibitory concentrations (MIC) of 15 compounds were determined at pH 7.2 and pH 6.0, using a broth microdilution assay. In addition, possible synergism was determined. MIC values for the three tested strains were similar. For organic acids, MIC values at pH 6.0 were lower than at pH 7.2. B. hyodysenteriae was most sensitive to cinnamaldehyde and lauric acid, with MIC values <1.5 mM. Most antibacterial effects of binary combinations were additive, however, for thymol and carvacrol, synergism could be observed. In vitro results demonstrate the antibacterial action of certain essential oil components and organic acids against B. hyodysenteriae. PMID:26369432

  20. In vitro susceptibility of Brachyspira hyodysenteriae to organic acids and essential oil components.

    PubMed

    Vande Maele, Lien; Heyndrickx, Marc; Maes, Dominiek; De Pauw, Nele; Mahu, Maxime; Verlinden, Marc; Haesebrouck, Freddy; Martel, An; Pasmans, Frank; Boyen, Filip

    2016-02-01

    The antibacterial potential of organic acids and essential oil components against Brachyspira hyodysenteriae, the causative pathogen of swine dysentery, was evaluated. Minimum inhibitory concentrations (MIC) of 15 compounds were determined at pH 7.2 and pH 6.0, using a broth microdilution assay. In addition, possible synergism was determined. MIC values for the three tested strains were similar. For organic acids, MIC values at pH 6.0 were lower than at pH 7.2. B. hyodysenteriae was most sensitive to cinnamaldehyde and lauric acid, with MIC values <1.5 mM. Most antibacterial effects of binary combinations were additive, however, for thymol and carvacrol, synergism could be observed. In vitro results demonstrate the antibacterial action of certain essential oil components and organic acids against B. hyodysenteriae.

  1. Dissimilar roles of the four conserved acidic residues in the thermal stability of poly(A)-specific ribonuclease.

    PubMed

    He, Guang-Jun; Liu, Wei-Feng; Yan, Yong-Bin

    2011-01-01

    Divalent metal ions are essential for the efficient catalysis and structural stability of many nucleotidyl-transfer enzymes. Poly(A)-specific ribonuclease (PARN) belongs to the DEDD superfamily of 3'-exonucleases, and the active site of PARN contains four conserved acidic amino acid residues that coordinate two Mg(2+) ions. In this research, we studied the roles of these four acidic residues in PARN thermal stability by mutational analysis. It was found that Mg(2+) significantly decreased the rate but increased the aggregate size of the 54 kDa wild-type PARN in a concentration-dependent manner. All of the four mutants decreased PARN thermal aggregation, while the aggregation kinetics of the mutants exhibited dissimilar Mg(2+)-dependent behavior. A comparison of the kinetic parameters indicated that Asp28 was the most crucial one to the binding of the two Mg(2+) ions, while metal B might be more important in PARN structural stability. The spectroscopic and aggregation results also suggested that the alterations in the active site structure by metal binding or mutations might lead to a global conformational change of the PARN molecule.

  2. A microalgae residue based carbon solid acid catalyst for biodiesel production.

    PubMed

    Fu, Xiaobo; Li, Dianhong; Chen, Jie; Zhang, Yuanming; Huang, Weiya; Zhu, Yi; Yang, Jun; Zhang, Chengwu

    2013-10-01

    Biodiesel production from microalgae is recognized as one of the best solutions to deal with the energy crisis issues. However, after the oil extraction from the microalgae, the microalgae residue was generally discarded or burned. Here a novel carbon-based solid acid catalyst derived from microalgae residue by in situ hydrothermal partially carbonization were synthesized. The obtained catalyst was characterized and subjected to both the esterification of oleic acid and transesterification of triglyceride to produce biodiesel. The catalyst showed high catalytic activity and can be regenerated while its activity can be well maintained after five cycles.

  3. Enhancing essential amino acids and health benefit components in grain crops for improved nutritional values.

    PubMed

    Wenefrida, Ida; Utomo, Herry S; Blanche, Sterling B; Linscombe, S D

    2009-01-01

    Improving essential amino acids or protein content, along with other phytonutrients in the food crops, will affect a great portion of the world population, especially in developing countries where rice grain is the main source of protein. Malnutrition, including deficiencies in protein/energy, iron/zinc, vitamin A, and iodine, causes a total 24,000 deaths per day worldwide. The problem is severe where rice is the major staple food. Protein deficiency involves both the quantity (amount) and quality (the content in essential amino acids) of the dietary protein. Various interventions, such as distribution, fortification, dietary diversification, and measures against infectious diseases, have been applied to reduce deficiency disorders. The problem, however, remains unsolved. Developing genetically novel lines with elevated content of essential amino acids together with other health benefit components becomes more feasible for the enhancement of breeding techniques, genomics, molecular manipulations, and genetic engineering. Advancement in basic genetic and genetic engineering has resulted in successful enrichment of some essential amino acids, such as lysine (Lys), tryptophan (Trp), and methionine (Met). Successful genetic enhancement has been largely restricted to the maize crop through enrichment of grain Lys and to some extends Trp. Since rice is the main source of calories and protein intake for billions of people, enhancing essential amino acids in rice represents a tremendous challenge. This paper will discuss and review the current status in basic genetics, molecular genetics, and genetic engineering associated with the enhancement of amino acids and other health benefit components in major grain crop improvement. Patents and future efforts associated with enhancing nutritional quality of the grain will also be reviewed as a concerted effort to solve the malnutrition problem and improve the quality of life worldwide.

  4. Polymorphisms at Amino Acid Residues 141 and 154 Influence Conformational Variation in Ovine PrP

    PubMed Central

    Yang, Sujeong; Thackray, Alana M.; Hopkins, Lee; Monie, Tom P.; Burke, David F.; Bujdoso, Raymond

    2014-01-01

    Polymorphisms in ovine PrP at amino acid residues 141 and 154 are associated with susceptibility to ovine prion disease: Leu141Arg154 with classical scrapie and Phe141Arg154 and Leu141His154 with atypical scrapie. Classical scrapie is naturally transmissible between sheep, whereas this may not be the case with atypical scrapie. Critical amino acid residues will determine the range or stability of structural changes within the ovine prion protein or its functional interaction with potential cofactors, during conversion of PrPC to PrPSc in these different forms of scrapie disease. Here we computationally identified that regions of ovine PrP, including those near amino acid residues 141 and 154, displayed more conservation than expected based on local structural environment. Molecular dynamics simulations showed these conserved regions of ovine PrP displayed genotypic differences in conformational repertoire and amino acid side-chain interactions. Significantly, Leu141Arg154 PrP adopted an extended beta sheet arrangement in the N-terminal palindromic region more frequently than the Phe141Arg154 and Leu141His154 variants. We supported these computational observations experimentally using circular dichroism spectroscopy and immunobiochemical studies on ovine recombinant PrP. Collectively, our observations show amino acid residues 141 and 154 influence secondary structure and conformational change in ovine PrP that may correlate with different forms of scrapie. PMID:25126555

  5. Effect of the secondary structure of carbohydrate residues of alpha 1-acid glycoprotein (orosomucoid) on the local dynamics of Trp residues.

    PubMed

    Albani, Jihad René

    2004-01-01

    We studied in this work the relation between the secondary structure of the carbohydrate residues of alpha1-acid glycoprotein and the local motions of Trp residues of the protein. We measured for this purpose the fluorescence emission intensity and anisotropy of the Trp residues between -46 and +30 degrees of the sialylated and asialylated protein. Our results indicate that, in both forms, the global profile of the emission intensity with temperature shows that Trp residues display static and collisional interaction with the neighboring amino acids. However, the profile of the asialylated form is more structured than that observed for the sialylated protein. The Y-plot analysis of the emission-anisotropy results indicated that the frictional resistance to rotation of the surface Trp residue is less important in the sialylated protein than in the asialylated form. This result is in good agreement with the fact that, in the asialylated conformation, the carbohydrate residues are closer to the protein surface than in the sialylated form, thereby increasing the contact of the surface Trp residue with the neighboring amino acids. Also, the interaction between the carbohydrate residues and the surface Trp residue contributes to the modification of the frictional resistance to rotation of the fluorophore.

  6. Evaluation of microwave-accelerated residue-specific acid cleavage for proteomic applications.

    PubMed

    Swatkoski, Stephen; Gutierrez, Peter; Wynne, Colin; Petrov, Alexey; Dinman, Jonathan D; Edwards, Nathan; Fenselau, Catherine

    2008-02-01

    Microwave-accelerated proteolysis using acetic acid has been shown to occur specifically on either or both sides of aspartic acid residues. This chemical cleavage has been applied to ovalbumin and several model peptides to test the effect on some of the more common post-translational modifications. No oxidation of methionine or cysteine was observed; however, hydrolysis of phosphate groups proceeds at a detectable rate. Acid cleavage was also extended to the yeast ribosome model proteome, where it provided information on 74% of that proteome. Aspartic acid occurs across the proteome with approximately half the frequency of the combined occurrence of the trypsin residues lysine and arginine, and implications of this are considered.

  7. Modification of amino acid residues in carious dentin matrix.

    PubMed

    Kleter, G A; Damen, J J; Buijs, M J; Ten Cate, J M

    1998-03-01

    The Maillard reaction between sugar and protein has been postulated as the cause for the browning and arrestment of caries lesions. This reaction has been implicated as the cause for decreased degradability of collagen in vivo. The aim of the present study was to verify the occurrence of the reaction in vivo. Carious and sound dentin samples were taken from extracted human teeth and analyzed for the fluorescence characteristic of the Maillard reaction and oxidation and, by HPLC, for Maillard products. In addition, physiological cross-links were analyzed by HPLC. Oxidation- and Maillard reaction-related fluorescence increased in collagenase digests from carious dentin. Advanced Maillard products (carboxymethyllysine and pentosidine) increased, whereas furosine, a marker for the initial reaction, was not observed consistently. This implies no direct addition of sugars to protein, but rather the addi-tion of smaller metabolites and glycoxidation products. In addition, the physiological cross-links hydroxylysinonorleucine and dihydroxylysinonorleucine decreased in carious dentin. Also for hydroxylysylpyridinoline, a decrease was observed, but not consistently. In conclusion, the caries process modifies amino acids in dentin collagen, which can lead to increased resistance against proteolysis and ultimately to caries arrestment.

  8. Evolutionary diversification of aminopeptidase N in Lepidoptera by conserved clade-specific amino acid residues.

    PubMed

    Hughes, Austin L

    2014-07-01

    Members of the aminopepidase N (APN) gene family of the insect order Lepidoptera (moths and butterflies) bind the naturally insecticidal Cry toxins produced by the bacterium Bacillus thuringiensis. Phylogenetic analysis of amino acid sequences of seven lepidopteran APN classes provided strong support for the hypothesis that lepidopteran APN2 class arose by gene duplication prior to the most recent common ancestor of Lepidoptera and Diptera. The Cry toxin-binding region (BR) of lepidopteran and dipteran APNs was subject to stronger purifying selection within APN classes than was the remainder of the molecule, reflecting conservation of catalytic site and adjoining residues within the BR. Of lepidopteran APN classes, APN2, APN6, and APN8 showed the strongest evidence of functional specialization, both in expression patterns and in the occurrence of conserved derived amino acid residues. The latter three APN classes also shared a convergently evolved conserved residue close to the catalytic site. APN8 showed a particularly strong tendency towards class-specific conserved residues, including one of the catalytic site residues in the BR and ten others in close vicinity to the catalytic site residues. The occurrence of class-specific sequences along with the conservation of enzymatic function is consistent with the hypothesis that the presence of Cry toxins in the environment has been a factor shaping the evolution of this multi-gene family.

  9. Revised Backbone-Virtual-Bond-Angle Potentials to Treat the l- and d-Amino Acid Residues in the Coarse-Grained United Residue (UNRES) Force Field

    PubMed Central

    2015-01-01

    Continuing our effort to introduce d-amino-acid residues in the united residue (UNRES) force field developed in our laboratory, in this work the Cα ··· Cα ··· Cα backbone-virtual-bond-valence-angle (θ) potentials for systems containing d-amino-acid residues have been developed. The potentials were determined by integrating the combined energy surfaces of all possible triplets of terminally blocked glycine, alanine, and proline obtained with ab initio molecular quantum mechanics at the MP2/6-31G(d,p) level to calculate the corresponding potentials of mean force (PMFs). Subsequently, analytical expressions were fitted to the PMFs to give the virtual-bond-valence potentials to be used in UNRES. Alanine represented all types of amino-acid residues except glycine and proline. The blocking groups were either the N-acetyl and N′,N′-dimethyl or N-acetyl and pyrrolidyl group, depending on whether the residue next in sequence was an alanine-type or a proline residue. A total of 126 potentials (63 symmetry-unrelated potentials for each set of terminally blocking groups) were determined. Together with the torsional, double-torsional, and side-chain-rotamer potentials for polypeptide chains containing d-amino-acid residues determined in our earlier work (Sieradzan et al. J. Chem. Theory Comput., 2012, 8, 4746), the new virtual-bond-angle (θ) potentials now constitute the complete set of physics-based potentials with which to run coarse-grained simulations of systems containing d-amino-acid residues. The ability of the extended UNRES force field to reproduce thermodynamics of polypeptide systems with d-amino-acid residues was tested by comparing the experimentally measured and the calculated free energies of helix formation of model KLALKLALxxLKLALKLA peptides, where x denotes any d- or l- amino-acid residue. The obtained results demonstrate that the UNRES force field with the new potentials reproduce the changes of free energies of helix formation upon d

  10. Identification of a key residue in Kv7.1 potassium channel essential for sensing external potassium ions

    PubMed Central

    Wang, Wenying; Flores, Maria Cristina Perez; Sihn, Choong-Ryoul; Kim, Hyo Jeong; Zhang, Yinuo; Doyle, Karen J.; Chiamvimonvat, Nipavan

    2015-01-01

    Kv7.1 voltage-gated K+ (Kv) channels are present in the apical membranes of marginal cells of the stria vascularis of the inner ear, where they mediate K+ efflux into the scala media (cochlear duct) of the cochlea. As such, they are exposed to the K+-rich (∼150 mM of external K+ (K+e)) environment of the endolymph. Previous studies have shown that Kv7.1 currents are substantially suppressed by high K+e (independent of the effects of altering the electrochemical gradient). However, the molecular basis for this inhibition, which is believed to involve stabilization of an inactivated state, remains unclear. Using sequence alignment of S5-pore linkers of several Kv channels, we identified a key residue, E290, found in only a few Kv channels including Kv7.1. We used substituted cysteine accessibility methods and patch-clamp analysis to provide evidence that the ability of Kv7.1 to sense K+e depends on E290, and that the charge at this position is essential for Kv7.1’s K+e sensitivity. We propose that Kv7.1 may use this feedback mechanism to maintain the magnitude of the endocochlear potential, which boosts the driving force to generate the receptor potential of hair cells. The implications of our findings transcend the auditory system; mutations at this position also result in long QT syndrome in the heart. PMID:25712016

  11. Isoelectric Point, Electric Charge, and Nomenclature of the Acid-Base Residues of Proteins

    ERIC Educational Resources Information Center

    Maldonado, Andres A.; Ribeiro, Joao M.; Sillero, Antonio

    2010-01-01

    The main object of this work is to present the pedagogical usefulness of the theoretical methods, developed in this laboratory, for the determination of the isoelectric point (pI) and the net electric charge of proteins together with some comments on the naming of the acid-base residues of proteins. (Contains 8 figures and 4 tables.)

  12. Progesterone binding to the tryptophan residues of human alpha1-acid glycoprotein.

    PubMed

    Albani, J R

    2006-11-06

    Binding studies between progesterone and alpha1-acid glycoprotein allowed us to demonstrate that the binding site of progesterone contains one hydrophobic tryptophan residue and that the structure of the protein is not altered upon binding. The data obtained at saturated concentrations of progesterone clearly reveal the type of interaction at physiological levels.

  13. Mycolic Acid Cyclopropanation is Essential for Viability, Drug Resistance, and Cell Wall Integrity of Mycobacterium tuberculosis

    SciTech Connect

    Barkan, Daniel; Liu, Zhen; Sacchettini, James C.; Glickman, Michael S.

    2009-12-01

    Mycobacterium tuberculosis infection remains a major global health problem complicated by escalating rates of antibiotic resistance. Despite the established role of mycolic acid cyclopropane modification in pathogenesis, the feasibility of targeting this enzyme family for antibiotic development is unknown. We show through genetics and chemical biology that mycolic acid methyltransferases are essential for M. tuberculosis viability, cell wall structure, and intrinsic resistance to antibiotics. The tool compound dioctylamine, which we show acts as a substrate mimic, directly inhibits the function of multiple mycolic acid methyltransferases, resulting in loss of cyclopropanation, cell death, loss of acid fastness, and synergistic killing with isoniazid and ciprofloxacin. These results demonstrate that mycolic acid methyltransferases are a promising antibiotic target and that a family of virulence factors can be chemically inhibited with effects not anticipated from studies of each individual enzyme.

  14. Achieving optimal essential fatty acid status in vegetarians: current knowledge and practical implications.

    PubMed

    Davis, Brenda C; Kris-Etherton, Penny M

    2003-09-01

    Although vegetarian diets are generally lower in total fat, saturated fat, and cholesterol than are nonvegetarian diets, they provide comparable levels of essential fatty acids. Vegetarian, especially vegan, diets are relatively low in alpha-linolenic acid (ALA) compared with linoleic acid (LA) and provide little, if any, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). Clinical studies suggest that tissue levels of long-chain n-3 fatty acids are depressed in vegetarians, particularly in vegans. n-3 Fatty acids have numerous physiologic benefits, including potent cardioprotective effects. These effects have been demonstrated for ALA as well as EPA and DHA, although the response is generally less for ALA than for EPA and DHA. Conversion of ALA by the body to the more active longer-chain metabolites is inefficient: < 5-10% for EPA and 2-5% for DHA. Thus, total n-3 requirements may be higher for vegetarians than for nonvegetarians, as vegetarians must rely on conversion of ALA to EPA and DHA. Because of the beneficial effects of n-3 fatty acids, it is recommended that vegetarians make dietary changes to optimize n-3 fatty acid status.

  15. Biosynthesis of Essential Polyunsaturated Fatty Acids in Wheat Triggered by Expression of Artificial Gene

    PubMed Central

    Mihálik, Daniel; Klčová, Lenka; Ondreičková, Katarína; Hudcovicová, Martina; Gubišová, Marcela; Klempová, Tatiana; Čertík, Milan; Pauk, János; Kraic, Ján

    2015-01-01

    The artificial gene D6D encoding the enzyme ∆6desaturase was designed and synthesized using the sequence of the same gene from the fungus Thamnidium elegans. The original start codon was replaced by the signal sequence derived from the wheat gene for high-molecular-weight glutenin subunit and the codon usage was completely changed for optimal expression in wheat. Synthesized artificial D6D gene was delivered into plants of the spring wheat line CY-45 and the gene itself, as well as transcribed D6D mRNA were confirmed in plants of T0 and T1 generations. The desired product of the wheat genetic modification by artificial D6D gene was the γ-linolenic acid. Its presence was confirmed in mature grains of transgenic wheat plants in the amount 0.04%–0.32% (v/v) of the total amount of fatty acids. Both newly synthesized γ-linolenic acid and stearidonic acid have been detected also in leaves, stems, roots, awns, paleas, rachillas, and immature grains of the T1 generation as well as in immature and mature grains of the T2 generation. Contents of γ-linolenic acid and stearidonic acid varied in range 0%–1.40% (v/v) and 0%–1.53% (v/v) from the total amount of fatty acids, respectively. This approach has opened the pathway of desaturation of fatty acids and production of essential polyunsaturated fatty acids in wheat. PMID:26694368

  16. Synthesis and antibacterial activity of some new non-proteinogenic amino acids containing thiazole residues.

    PubMed

    Stanchev, M; Pajpanova, T; Golovinsky, E

    2000-01-01

    Some new thioamides and thiazoles have been synthesized using canavanine, S-cysteine, homo-S-cysteinesulfonamides and their N-omega aminoethylated derivatives as adducts in order to investigate the structure-antimicrobial activity relationships. The compounds showed substantial antibacterial activity in vitro against various gram-positive (Staphylococcus aureus, Bacillus cereus etc.) and gram-negative (Escherichia coli, Proteus vulgaris etc.) bacteria. These findings indicate that the presence of the thiazole residue is an essential factor for the antibacterial effect.

  17. Uniformly sup 13 C-labeled algal protein used to determine amino acid essentiality in vivo

    SciTech Connect

    Berthold, H.K.; Hachey, D.L.; Reeds, P.J.; Klein, P.D. ); Thomas, O.P. ); Hoeksema, S. )

    1991-09-15

    The edible alga Spirulina platensis was uniformly labeled with {sup 13}C by growth in an atmosphere of pure {sup 13}CO{sub 2}. The labeled biomass was then incorporated into the diet of a laying hen for 27 days. The isotopic enrichment of individual amino acids in egg white and yolk proteins, as well as in various tissues of the hen at the end of the feeding period, was analyzed by negative chemical ionization gas chromatography/mass spectrometry. The amino acids of successive eggs showed one of two exclusive enrichment patterns: complete preservation of the intact carbon skeleton or extensive degradation and resynthesis. The same observation was made in tissue proteins. These patterns were cleanly divided according to known nutritional amino acid essentiality/nonessentiality but revealed differences in labeling among the nonessential amino acids: most notable was that proline accretion was derived entirely from the diet. Feeding uniformly {sup 13}C-labeled algal protein and recovering and analyzing de novo-synthesized protein provides a useful method to examine amino acid metabolism and determine conditional amino acid essentially in vivo.

  18. FSH receptor-specific residues L501 and I505 in extracellular loop 2 are essential for its function.

    PubMed

    Banerjee, Antara A; Dupakuntla, Madhavi; Pathak, Bhakti R; Mahale, Smita D

    2015-06-01

    The extracellular loop 2 (EL2) of FSH receptor (FSHR) plays a pivotal role in various events downstream of FSH stimulation. Because swapping the six FSHR-specific residues in EL2 (chimeric EL2M) with those from LH/choriogonadotropin receptor resulted in impaired internalization of FSH-FSHR complex and low FSH-induced cAMP production, six substitution mutants of EL2 were generated to ascertain the contribution of individual amino acids to the effects shown by chimeric EL2M. Results revealed that L(501)F mainly and I(505)V to a lesser extent contribute to the diminished receptor function in chimeric EL2M. HEK293 cells stably expressing WT and chimeric EL2M FSHR were generated to track the fate of the receptors post FSH induction. The chimeric EL2M FSHR stable clone showed weak internalization and cAMP response similar to transiently transfected cells. Furthermore, reduced FSH-induced ERK phosphorylation was also observed. The interaction of activated chimeric EL2M and L(501)F FSHR with β-arrestins was weak compared with WT FSHR, thus explaining the impaired internalization of chimeric EL2M and corroborating the indispensable role of EL2 in receptor function.

  19. Residual mitochondrial transmembrane potential decreases unsaturated fatty acid level in sake yeast during alcoholic fermentation.

    PubMed

    Sawada, Kazutaka; Kitagaki, Hiroshi

    2016-01-01

    Oxygen, a key nutrient in alcoholic fermentation, is rapidly depleted during this process. Several pathways of oxygen utilization have been reported in the yeast Saccharomyces cerevisiae during alcoholic fermentation, namely synthesis of unsaturated fatty acid, sterols and heme, and the mitochondrial electron transport chain. However, the interaction between these pathways has not been investigated. In this study, we showed that the major proportion of unsaturated fatty acids of ester-linked lipids in sake fermentation mash is derived from the sake yeast rather than from rice or koji (rice fermented with Aspergillus). Additionally, during alcoholic fermentation, inhibition of the residual mitochondrial activity of sake yeast increases the levels of unsaturated fatty acids of ester-linked lipids. These findings indicate that the residual activity of the mitochondrial electron transport chain reduces molecular oxygen levels and decreases the synthesis of unsaturated fatty acids, thereby increasing the synthesis of estery flavors by sake yeast. This is the first report of a novel link between residual mitochondrial transmembrane potential and the synthesis of unsaturated fatty acids by the brewery yeast during alcoholic fermentation.

  20. Neisseria meningitidis Translation Elongation Factor P and Its Active-Site Arginine Residue Are Essential for Cell Viability

    PubMed Central

    Yanagisawa, Tatsuo; Takahashi, Hideyuki; Suzuki, Takehiro; Masuda, Akiko; Dohmae, Naoshi; Yokoyama, Shigeyuki

    2016-01-01

    Translation elongation factor P (EF-P), a ubiquitous protein over the entire range of bacterial species, rescues ribosomal stalling at consecutive prolines in proteins. In Escherichia coli and Salmonella enterica, the post-translational β-lysyl modification of Lys34 of EF-P is important for the EF-P activity. The β-lysyl EF-P modification pathway is conserved among only 26–28% of bacteria. Recently, it was found that the Shewanella oneidensis and Pseudomonas aeruginosa EF-P proteins, containing an Arg residue at position 32, are modified with rhamnose, which is a novel post-translational modification. In these bacteria, EF-P and its Arg modification are both dispensable for cell viability, similar to the E. coli and S. enterica EF-P proteins and their Lys34 modification. However, in the present study, we found that EF-P and Arg32 are essential for the viability of the human pathogen, Neisseria meningitidis. We therefore analyzed the modification of Arg32 in the N. meningitidis EF-P protein, and identified the same rhamnosyl modification as in the S. oneidensis and P. aeruginosa EF-P proteins. N. meningitidis also has the orthologue of the rhamnosyl modification enzyme (EarP) from S. oneidensis and P. aeruginosa. Therefore, EarP should be a promising target for antibacterial drug development specifically against N. meningitidis. The pair of genes encoding N. meningitidis EF-P and EarP suppressed the slow-growth phenotype of the EF-P-deficient mutant of E. coli, indicating that the activity of N. meningitidis rhamnosyl–EF-P for rescuing the stalled ribosomes at proline stretches is similar to that of E. coli β-lysyl–EF-P. The possible reasons for the unique requirement of rhamnosyl–EF-P for N. meningitidis cells are that more proline stretch-containing proteins are essential and/or the basal ribosomal activity to synthesize proline stretch-containing proteins in the absence of EF-P is lower in this bacterium than in others. PMID:26840407

  1. Comparison between conjugated linoleic acid and essential fatty acids in preventing oxidative stress in bovine mammary epithelial cells.

    PubMed

    Basiricò, L; Morera, P; Dipasquale, D; Tröscher, A; Bernabucci, U

    2017-03-01

    Some in vitro and in vivo studies have demonstrated protective effects of conjugated linoleic acid (CLA) isomers against oxidative stress and lipid peroxidation. However, only a few and conflicting studies have been conducted showing the antioxidant potential of essential fatty acids. The objectives of the study were to compare the effects of CLA to other essential fatty acids on the thiol redox status of bovine mammary epithelia cells (BME-UV1) and their protective role against oxidative damage on the mammary gland by an in vitro study. The BME-UV1 cells were treated with complete medium containing 50 μM of cis-9,trans-11 CLA, trans-10,cis-12 CLA, α-linolenic acid, γ-linolenic acid, and linoleic acid. To assess the cellular antioxidant response, glutathione, NADPH, and γ-glutamyl-cysteine ligase activity were measured 48 h after addition of fatty acids (FA). Intracellular reactive oxygen species and malondialdehyde production were also assessed in cells supplemented with FA. Reactive oxygen species production after 3 h of H2O2 exposure was assessed to evaluate and to compare the potential protection of different FA against H2O2-induced oxidative stress. All FA treatments induced an intracellular GSH increase, matched by high concentrations of NADPH and an increase of γ-glutamyl-cysteine ligase activity. Cells supplemented with FA showed a reduction in intracellular malondialdehyde levels. In particular, CLA isomers and linoleic acid supplementation showed a better antioxidant cellular response against oxidative damage induced by H2O2 compared with other FA.

  2. Identification of conserved amino acid residues critical for human immunodeficiency virus type 1 integrase function in vitro.

    PubMed Central

    Engelman, A; Craigie, R

    1992-01-01

    We have probed the structural organization of the human immunodeficiency virus type 1 integrase protein by limited proteolysis and the functional organization by site-directed mutagenesis of selected amino acid residues. A central region of the protein was relatively resistant to proteolysis. Proteins with altered amino acids in this region, or in the N-terminal part of the protein that includes a putative zinc-binding motif, were purified and assayed for 3' processing, DNA strand transfer, and disintegration activities in vitro. In general, these mutations had parallel effects on 3' processing and DNA strand transfer, suggesting that integrase may utilize a single active site for both reactions. The only proteins that were completely inactive in all three assays contained mutations at conserved amino acids in the central region, suggesting that this part of the protein may be involved in catalysis. In contrast, none of the mutations in the N-terminal region resulted in a protein that was inactive in all three assays, suggesting that this part of integrase may not be essential for catalysis. The disintegration reaction was particularly insensitive to these amino acid substitutions, indicating that some function that is important for 3' processing and DNA strand transfer may be dispensable for disintegration. Images PMID:1404595

  3. Identification of Essential Amino Acids in the Azorhizobium caulinodans Fucosyltransferase NodZ†

    PubMed Central

    Chazalet, Valerie; Uehara, Kazuyoshi; Geremia, Roberto A.; Breton, Christelle

    2001-01-01

    The nodZ gene, which is present in various rhizobial species, is involved in the addition of a fucose residue in an α1-6 linkage to the reducing N-acetylglucosamine residue of lipo-chitin oligosaccharide signal molecules, the so-called Nod factors. Fucosylation of Nod factors is known to affect nodulation efficiency and host specificity. Despite a lack of overall sequence identity, NodZ proteins share conserved peptide motifs with mammalian and plant fucosyltransferases that participate in the biosynthesis of complex glycans and polysaccharides. These peptide motifs are thought to play important roles in catalysis. NodZ was expressed as an active and soluble form in Escherichia coli and was subjected to site-directed mutagenesis to investigate the role of the most conserved residues. Enzyme assays demonstrate that the replacement of the invariant Arg-182 by either alanine, lysine, or aspartate results in products with no detectable activity. A similar result is obtained with the replacement of the conserved acidic position (Asp-275) into its corresponding amide form. The residues His-183 and Asn-185 appear to fulfill functions that are more specific to the NodZ subfamily. Secondary structure predictions and threading analyses suggest the presence of a “Rossmann-type” nucleotide binding domain in the half C-terminal part of the catalytic domain of fucosyltransferases. Site-directed mutagenesis combined with theoretical approaches have shed light on the possible nucleotide donor recognition mode for NodZ and related fucosyltransferases. PMID:11717264

  4. Identification of the amino acid residues responsible for stable nucleosome formation by histone H3.Y.

    PubMed

    Kujirai, Tomoya; Horikoshi, Naoki; Xie, Yan; Taguchi, Hiroyuki; Kurumizaka, Hitoshi

    2017-01-24

    Histone H3.Y is conserved among primates. We previously reported that exogenously produced H3.Y accumulates around transcription start sites, suggesting that it may play a role in transcription regulation. The H3.Y nucleosome forms a relaxed chromatin conformation with flexible DNA ends. The H3.Y-specific Lys42 residue is partly responsible for enhancing the flexibility of the nucleosomal DNA. To our surprise, we found that H3.Y stably associates with chromatin and nucleosomes in vivo and in vitro. However, the H3.Y residues responsible for its stable nucleosome incorporation have not been identified yet. In the present study, we performed comprehensive mutational analyses of H3.Y, and determined that the H3.Y C-terminal region including amino acid residues 124-135 is responsible for its stable association with DNA. Among the H3.Y C-terminal residues, the H3.Y Met124 residue significantly contributed to the stable DNA association with the H3.Y-H4 tetramer. The H3.Y M124I mutation substantially reduced the H3.Y-H4 association in the nucleosome. In contrast, the H3.Y K42R mutation affected the nucleosome stability less, although it contributes to the flexible DNA ends of the nucleosome. Therefore, these H3.Y-specific residues, Lys42 and Met124, play different and specific roles in nucleosomal DNA relaxation and stable nucleosome formation, respectively, in chromatin.

  5. Intramolecular cyclization of aspartic acid residues assisted by three water molecules: a density functional theory study

    NASA Astrophysics Data System (ADS)

    Takahashi, Ohgi; Kirikoshi, Ryota

    2014-01-01

    Aspartic acid (Asp) residues in peptides and proteins (l-Asp) are known to undergo spontaneous nonenzymatic reactions to form l-β-Asp, d-Asp, and d-β-Asp residues. The formation of these abnormal Asp residues in proteins may affect their three-dimensional structures and hence their properties and functions. Indeed, the reactions have been thought to contribute to aging and pathologies. Most of the above reactions of the l-Asp residues proceed via a cyclic succinimide intermediate. In this paper, a novel three-water-assisted mechanism is proposed for cyclization of an Asp residue (forming a gem-diol precursor of the succinimide) by the B3LYP/6-31 + G(d,p) density functional theory calculations carried out for an Asp-containing model compound (Ace-Asp-Nme, where Ace = acetyl and Nme = NHCH3). The three water molecules act as catalysts by mediating ‘long-range’ proton transfers. In the proposed mechanism, the amide group on the C-terminal side of the Asp residue is first converted to the tautomeric iminol form (iminolization). Then, reorientation of a water molecule and a conformational change occur successively, followed by the nucleophilic attack of the iminol nitrogen on the carboxyl carbon of the Asp side chain to form the gem-diol species. A satisfactory agreement was obtained between the calculated and experimental energetics.

  6. A Hexasaccharide Containing Rare 2‐O‐Sulfate‐Glucuronic Acid Residues Selectively Activates Heparin Cofactor II

    PubMed Central

    Sankarayanarayanan, Nehru Viji; Strebel, Tamara R.; Boothello, Rio S.; Sheerin, Kevin; Raghuraman, Arjun; Sallas, Florence; Mosier, Philip D.; Watermeyer, Nicholas D.

    2017-01-01

    Abstract Glycosaminoglycan (GAG) sequences that selectively target heparin cofactor II (HCII), a key serpin present in human plasma, remain unknown. Using a computational strategy on a library of 46 656 heparan sulfate hexasaccharides we identified a rare sequence consisting of consecutive glucuronic acid 2‐O‐sulfate residues as selectively targeting HCII. This and four other unique hexasaccharides were chemically synthesized. The designed sequence was found to activate HCII ca. 250‐fold, while leaving aside antithrombin, a closely related serpin, essentially unactivated. This group of rare designed hexasaccharides will help understand HCII function. More importantly, our results show for the first time that rigorous use of computational techniques can lead to discovery of unique GAG sequences that can selectively target GAG‐binding protein(s), which may lead to chemical biology or drug discovery tools. PMID:28124818

  7. Essential fatty acid deficiency profile in patients with nephrotic-range proteinuria.

    PubMed

    Aldámiz-Echevarría, Luis; Vallo, Alfredo; Aguirre, Mireia; Sanjurjo, Pablo; Gonzalez-Lamuño, Domingo; Elorz, Javier; Prieto, José Angel; Andrade, Fernando; Rodríguez-Soriano, Juan

    2007-04-01

    Plasma free fatty acids are bound to albumin, filtered through the glomeruli, and reabsorbed at the proximal nephron. The aim of the present investigation was to determine if urinary loss of fatty acids results in essential fatty acid (EFA) deficiency in patients with nephrotic-range proteinuria. We studied 12 patients aged 9 months to 23 years (eight male, four female) four suffering from congenital nephrotic syndrome (NS) and eight from different renal diseases. Six patients were studied postrenal transplantation. Proteinuria ranged between 41 and 829 mg/m2/h. Results were compared with data obtained in 83 healthy children. The patients had significantly lower values for plasma arachidonic acid content and EFA index (omega3 + omega6/omega7 + omega9). Deficiency in polyunsaturated fatty acids (PUFA) was especially manifest in infants with congenital NS. Plasma content of arachidonic and docosahexaenoic acids related negatively with the degree of proteinuria. In the lineal regression model, the degree of proteinuria explained 60% of the variability of plasma values of those fatty acids. We conclude that plasma fatty acid status should be regularly monitored in patients with nephrotic-range proteinuria, especially in young infants with congenital NS, who represent a population at special risk with regard to neurological development.

  8. The prediction of the degree of exposure to solvent of amino acid residues via genetic programming

    SciTech Connect

    Handley, S.

    1994-12-31

    In this paper I evolve programs that predict the degree of exposure to solvent (the buriedness) of amino acid residues given only the primary structure. I use genetic programming to evolve programs that take as input the primary structure and that output the buriedness of each residue. I trained these programs on a set of 82 proteins from the Brookhaven Protein Data Bank (PDB) and cross-validated them on a separate testing set of 40 proteins, also from the PDB. The best program evolved had a correlation of 0.434 between the predicted and observed buriednesses on the testing set.

  9. Thiostrepton Variants Containing a Contracted Quinaldic Acid Macrocycle Result from Mutagenesis of the Second Residue

    PubMed Central

    Zhang, Feifei; Li, Chaoxuan

    2016-01-01

    The thiopeptides are a family of ribosomally synthesized and posttranslationally modified peptide metabolites, and the vast majority of thiopeptides characterized to date possess one highly modified macrocycle. A few members, including thiostrepton A, harbor a second macrocycle that incorporates a quinaldic acid moiety and the four N-terminal residues of the peptide. The antibacterial properties of thiostrepton A are well established, and its recently discovered ability to inhibit the proteasome has additional implications for the development of antimalarial and anticancer therapeutics. We have conducted the saturation mutagenesis of Ala2 in the precursor peptide, TsrA, to examine which variants can be transformed into a mature thiostrepton analogue. Although the thiostrepton biosynthetic system is somewhat restrictive towards substitutions at the second residue, eight thiostrepton Ala2 analogues were isolated. The TsrA Ala2Ile and Ala2Val variants were largely channeled through an alternate processing pathway wherein the first residue of the core peptide, Ile1, is removed and the resulting thiostrepton analogues bear quinaldic acid macrocycles abridged by one residue. This is the first report revealing that quinaldic acid loop size is amenable to alteration during the course of thiostrepton biosynthesis. Both the antibacterial and proteasome inhibitory properties of the thiostrepton Ala2 analogues were examined. While the identity of the residue at the second position of the core peptide influences thiostrepton biosynthesis, our report suggests it may not be crucial for antibacterial and proteasome inhibitory properties of the full-length variants. In contrast, the contracted quinaldic acid loop can, to differing degrees, affect both types of biological activity. PMID:26630475

  10. The influence of dietary essential fatty acids on uterine C20 and C22 fatty acid composition.

    PubMed

    Howie, A; Leaver, H A; Wilson, N H; Yap, P L; Aitken, I D

    1992-06-01

    The effect of dietary fatty acids on uterine fatty acid composition was studied in rats fed control diet or semi-synthetic diet supplemented with 1.5 microliter/g/day evening primrose oil (EPO) or fish oil (FO). Diet-related changes in uterine lipid were detected within 21 days. Changes of 2- to 20-fold were detected in the uterine n-6 and n-3 essential fatty acids (EFA) and in certain saturated and monounsaturated fatty acids. The FO diet was associated with higher uterine C20 and C22 n-3, and the EPO diet, with higher uterine n-6 fatty acid. High uterine C18:2 n-6 was detected in neutral lipid (NL) of rats fed high concentrations of this fatty acid, but there was little evidence of selective incorporation or retention of C18:2 n-6 by uterine NL. The incorporation of EFA into uterine phospholipids (PL) was greater than NL EFA incorporation, and uterine PL n-3/n-6 ratios showed greater diet dependence. Tissue/diet fatty acid ratios in NL and PL also indicated preferential incorporation/synthesis of C16:1 n-9, and C16:0, and there was greater incorporation of C12:0 and C14:0 into uteri of rats fed EPO and FO. Replacement of 50-60% of arachidonate with n-3 EFA in uterine PL may inhibit n-6 EFA metabolism necessary for uterine function at parturition.

  11. [Inhibitory effect of essential oils, food additives, peracetic acid and detergents on bacterial histidine decarboxylase].

    PubMed

    Kamii, Eri; Terada, Gaku; Akiyama, Jyunki; Isshiki, Kenji

    2011-01-01

    The aim of this study is to examine whether various essential oils, food additives, peracetic acid and detergents inhibit bacterial histidine decarboxylase. Crude extract of Morganella morganii NBRC3848 was prepared and incubated with various agents. Histidine decarboxylase activity was significantly inhibited (p<0.05) by 26 of 45 compounds tested. Among the 26 agents, sodium hypochlorite completely decomposed both histidine and histamine, while peracetic acid caused slight decomposition. Histidine and histamine were stable in the presence of the other 24 agents. These results indicated that 25 of the agents examined were inhibitors of histidine decarboxylase.

  12. Increasing CO2 differentially affects essential and non-essential amino acid concentration of rice grains grown in cadmium-contaminated soils.

    PubMed

    Wu, Huibin; Song, Zhengguo; Wang, Xiao; Liu, Zhongqi; Tang, Shirong

    2016-09-01

    Environmental pollution by both ambient CO2 and heavy metals has been steadily increasing, but we do not know how fluctuating CO2 concentrations influence plant nutrients under high Cd pollution, especially in crops. Here, we studied the effects of elevated CO2 and Cd accumulation on proteins and amino acids in rice under Cd stress. In this pot experiment, we analyzed the amino-acid profile of 20 rice cultivars that accumulate Cd differently; the plants were grown in Cd-containing soils under ambient conditions and elevated CO2 levels. We found that although Cd concentrations appeared to be higher in most cultivars under elevated CO2 than under ambient CO2, the effect was significant only in seven cultivars. Combined exposure to Cd and elevated CO2 strongly decreased rice protein and amino acid profiles, including essential and non-essential amino acids. Under elevated CO2, the ratios of specific amino acids were either higher or lower than the optimal ratios provided by FAO/WHO, suggesting that CO2 may flatten the overall amino-acid profile, leading to an excess in some amino acids and deficiencies in others when the rice is consumed. Thus, Cd-tainted rice limits the concentration of essential amino acids in rice-based diets, and the combination with elevated CO2 further exacerbates the problem.

  13. A novel sono-assisted acid pretreatment of chili post harvest residue for bioethanol production.

    PubMed

    Sindhu, Raveendran; Binod, Parameswaran; Pandey, Ashok

    2016-08-01

    The objective of the present study was to develop a sono-assisted acid pretreatment strategy for the effective removal of lignin and hemicelluloses and to improve the sugar yield from chili post harvest residue. Operational parameters that affect the pretreatment efficiency were studied and optimized. Inhibitor analysis of the hydrolyzate revealed that major fermentation inhibitors like furfural, hydroxymethyl furfural and organic acids like citric acid, succinic acid and propionic acid were absent. Changes in structural properties of the biomass were studied in relation to the pretreatment process using scanning electron microscopy (SEM), X-ray diffraction (XRD) and Fourier Transform Infrared (FTIR) analysis, and the changes in chemical composition was also monitored. The biomass pretreated with the optimized novel method yielded 0.465g/g of reducing sugars on enzymatic hydrolysis. Fermentation of the non-detoxified hydrolysate yielded 2.14% of bioethanol with a fermentation efficiency of 71.03%.

  14. Cyclopropanation of Membrane Unsaturated Fatty Acids Is Not Essential to the Acid Stress Response of Lactococcus lactis subsp. cremoris ▿

    PubMed Central

    To, Thi Mai Huong; Grandvalet, Cosette; Tourdot-Maréchal, Raphaëlle

    2011-01-01

    Cyclopropane fatty acids (CFAs) are synthetized in situ by the transfer of a methylene group from S-adenosyl-l-methionine to a double bond of unsaturated fatty acid chains of membrane phospholipids. This conversion, catalyzed by the Cfa synthase enzyme, occurs in many bacteria and is recognized to play a key role in the adaptation of bacteria in response to a drastic perturbation of the environment. The role of CFAs in the acid tolerance response was investigated in the lactic acid bacterium Lactococcus lactis MG1363. A mutant of the cfa gene was constructed by allelic exchange. The cfa gene encoding the Cfa synthase was cloned and introduced into the mutant to obtain the complemented strain for homologous system studies. Data obtained by gas chromatography (GC) and GC-mass spectrometry (GC-MS) validated that the mutant could not produce CFA. The CFA levels in both the wild-type and complemented strains increased upon their entry to stationary phase, especially with acid-adapted cells or, more surprisingly, with ethanol-adapted cells. The results obtained by performing quantitative reverse transcription-PCR (qRT-PCR) experiments showed that transcription of the cfa gene was highly induced by acidity (by 10-fold with cells grown at pH 5.0) and by ethanol (by 9-fold with cells grown with 6% ethanol) in comparison with that in stationary phase. Cell viability experiments were performed after an acidic shock on the mutant strain, the wild-type strain, and the complemented strain, as a control. The higher viability level of the acid-adapted cells of the three strains after 3 h of shock proved that the cyclopropanation of unsaturated fatty acids is not essential for L. lactis subsp. cremoris survival under acidic conditions. Moreover, fluorescence anisotropy data showed that CFA itself could not maintain the membrane fluidity level, particularly with ethanol-grown cells. PMID:21421775

  15. Cyclopropanation of membrane unsaturated fatty acids is not essential to the acid stress response of Lactococcus lactis subsp. cremoris.

    PubMed

    To, Thi Mai Huong; Grandvalet, Cosette; Tourdot-Maréchal, Raphaëlle

    2011-05-01

    Cyclopropane fatty acids (CFAs) are synthetized in situ by the transfer of a methylene group from S-adenosyl-L-methionine to a double bond of unsaturated fatty acid chains of membrane phospholipids. This conversion, catalyzed by the Cfa synthase enzyme, occurs in many bacteria and is recognized to play a key role in the adaptation of bacteria in response to a drastic perturbation of the environment. The role of CFAs in the acid tolerance response was investigated in the lactic acid bacterium Lactococcus lactis MG1363. A mutant of the cfa gene was constructed by allelic exchange. The cfa gene encoding the Cfa synthase was cloned and introduced into the mutant to obtain the complemented strain for homologous system studies. Data obtained by gas chromatography (GC) and GC-mass spectrometry (GC-MS) validated that the mutant could not produce CFA. The CFA levels in both the wild-type and complemented strains increased upon their entry to stationary phase, especially with acid-adapted cells or, more surprisingly, with ethanol-adapted cells. The results obtained by performing quantitative reverse transcription-PCR (qRT-PCR) experiments showed that transcription of the cfa gene was highly induced by acidity (by 10-fold with cells grown at pH 5.0) and by ethanol (by 9-fold with cells grown with 6% ethanol) in comparison with that in stationary phase. Cell viability experiments were performed after an acidic shock on the mutant strain, the wild-type strain, and the complemented strain, as a control. The higher viability level of the acid-adapted cells of the three strains after 3 h of shock proved that the cyclopropanation of unsaturated fatty acids is not essential for L. lactis subsp. cremoris survival under acidic conditions. Moreover, fluorescence anisotropy data showed that CFA itself could not maintain the membrane fluidity level, particularly with ethanol-grown cells.

  16. Conjugated fatty acid synthesis: residues 111 and 115 influence product partitioning of Momordica charantia conjugase.

    PubMed

    Rawat, Richa; Yu, Xiao-Hong; Sweet, Marie; Shanklin, John

    2012-05-11

    Conjugated linolenic acids (CLNs), 18:3 Δ(9,11,13), lack the methylene groups found between the double bonds of linolenic acid (18:3 Δ(9,12,15)). CLNs are produced by conjugase enzymes that are homologs of the oleate desaturases FAD2. The goal of this study was to map the domain(s) within the Momordica charantia conjugase (FADX) responsible for CLN formation. To achieve this, a series of Momordica FADX-Arabidopsis FAD2 chimeras were expressed in the Arabidopsis fad3fae1 mutant, and the transformed seeds were analyzed for the accumulation of CLN. These experiments identified helix 2 and the first histidine box as a determinant of conjugase product partitioning into punicic acid (18:3 Δ(9cis,11trans,13cis)) or α-eleostearic acid (18:3 Δ(9cis,11trans,13trans)). This was confirmed by analysis of a FADX mutant containing six substitutions in which the sequence of helix 2 and first histidine box was converted to that of FAD2. Each of the six FAD2 substitutions was individually converted back to the FADX equivalent identifying residues 111 and 115, adjacent to the first histidine box, as key determinants of conjugase product partitioning. Additionally, expression of FADX G111V and FADX G111V/D115E resulted in an approximate doubling of eleostearic acid accumulation to 20.4% and 21.2%, respectively, compared with 9.9% upon expression of the native Momordica FADX. Like the Momordica conjugase, FADX G111V and FADX D115E produced predominantly α-eleostearic acid and little punicic acid, but the FADX G111V/D115E double mutant produced approximately equal amounts of α-eleostearic acid and its isomer, punicic acid, implicating an interactive effect of residues 111 and 115 in punicic acid formation.

  17. Relation between the secondary structure of carbohydrate residues of alpha1-acid glycoprotein (orosomucoid) and the fluorescence of the protein.

    PubMed

    Albani, Jihad R

    2003-05-01

    We studied in this work the relation that exists between the secondary structure of the glycans of alpha(1)-acid glycoprotein and the fluorescence of the Trp residues of the protein. We calculated for that the efficiency of quenching and the radiative and non-radiative constants. Our results indicate that the glycans display a spatial structure that is modified upon asialylation. The asialylated conformation is closer to the protein matrix than the sialylated form, inducing by that a decrease in the fluorescence parameters of the Trp residues. In fact, the mean quantum yield of Trp residues in sialylated and asialylated alpha(1)-acid glycoprotein are 0.0645 and 0.0385, respectively. Analysis of the fluorescence emission of alpha(1)-acid glycoprotein as the result of two contributions (surface and hydrophobic domains) indicates that quantum yields of both classes of Trp residues are lower when the protein is in the asialylated form. Also, the mean fluorescence lifetime of Trp residues decreases from 2.285 ns in the sialylated protein to 1.948 ns in the asialylated one. The radiative rate constant k(r) of the Trp residues in the sialylated alpha(1)-acid glycoprotein is higher than that in the asialylated protein. Thus, the carbohydrate residues are closer to the Trp residues in the absence of sialic acid. The modification of the spatial conformation of the glycans upon asialylation is confirmed by the decrease of the fluorescence lifetimes of Calcofluor, a fluorophore that binds to the carbohydrate residues. Finally, thermal intensity quenching of Calcofluor bound to alpha(1)-acid glycoprotein shows that the carbohydrate residues have slower residual motions in the absence of sialic acid residues.

  18. Lake eutrophication and brownification downgrade availability and transfer of essential fatty acids for human consumption.

    PubMed

    Taipale, S J; Vuorio, K; Strandberg, U; Kahilainen, K K; Järvinen, M; Hiltunen, M; Peltomaa, E; Kankaala, P

    2016-11-01

    Fish are an important source of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) for birds, mammals and humans. In aquatic food webs, these highly unsaturated fatty acids (HUFA) are essential for many physiological processes and mainly synthetized by distinct phytoplankton taxa. Consumers at different trophic levels obtain essential fatty acids from their diet because they cannot produce these sufficiently de novo. Here, we evaluated how the increase in phosphorus concentration (eutrophication) or terrestrial organic matter inputs (brownification) change EPA and DHA content in the phytoplankton. Then, we evaluated whether these changes can be seen in the EPA and DHA content of piscivorous European perch (Perca fluviatilis), which is a widely distributed species and commonly consumed by humans. Data from 713 lakes showed statistically significant differences in the abundance of EPA- and DHA-synthesizing phytoplankton as well as in the concentrations and content of these essential fatty acids among oligo-mesotrophic, eutrophic and dystrophic lakes. The EPA and DHA content of phytoplankton biomass (mgHUFAg(-1)) was significantly lower in the eutrophic lakes than in the oligo-mesotrophic or dystrophic lakes. We found a strong significant correlation between the DHA content in the muscle of piscivorous perch and phytoplankton DHA content (r=0.85) as well with the contribution of DHA-synthesizing phytoplankton taxa (r=0.83). Among all DHA-synthesizing phytoplankton this correlation was the strongest with the dinoflagellates (r=0.74) and chrysophytes (r=0.70). Accordingly, the EPA+DHA content of perch muscle decreased with increasing total phosphorus (r(2)=0.80) and dissolved organic carbon concentration (r(2)=0.83) in the lakes. Our results suggest that although eutrophication generally increase biomass production across different trophic levels, the high proportion of low-quality primary producers reduce EPA and DHA content in the food web up to predatory fish

  19. Polyamines are essential for the synthesis of 2-ricinoleoyl phosphatidic acid in developing seeds of castor.

    PubMed

    Tomosugi, Mitsuhiro; Ichihara, Ken'ichi; Saito, Kazumi

    2006-01-01

    The major fatty acid component of castor (Ricinus communis L.) oil is ricinoleic acid (12-hydroxy-cis-9-octadecenoic acid), and unsaturated hydroxy acid accounts for >85% of the total fatty acids in triacylglycerol (TAG). TAG had a higher ricinoleate content at position 2 than at positions 1 and 3. Although lysophosphatidic acid (LPA) acyltransferase (EC 2.3.1.51), which catalyzes acylation of LPA at position 2, was expected to utilize ricinoleoyl-CoA preferentially over other fatty acyl-CoAs, no activity was found for ricinoleoyl-CoA in vitro at concentrations at which other unsaturated acyl-CoAs were incorporated rapidly. However, activity for ricinoleoyl-CoA appeared with addition of polyamines (putrescine, spermidine, and spermine), while polyamines decreased the rates of incorporation of other acyl-CoAs into position 2. The order of effect of polyamines on LPA acyltransferase activity was spermine > spermidine > putrescine. At concentrations of spermine and spermidine of >0.1 mM, ricinoleoyl-CoA served as an effective substrate for LPA acyltransferase reaction. The concentrations of spermine and spermidine in the developing seeds were estimated at approximately 0.09 and approximately 0.63 mM, respectively. These stimulatory effects for incorporation of ricinoleate were specific to polyamines, but basic amino acids were ineffective as cations. In contrast, in microsomes from safflower seeds that do not contain ricinoleic acid, spermine and spermidine stimulated the LPA acyltransferase reaction for all acyl-CoAs tested, including ricinoleoyl-CoA. Although the fatty acid composition of TAG depends on both acyl-CoA composition in the cell and substrate specificity of acyltransferases, castor bean polyamines are crucial for incorporation of ricinoleate into position 2 of LPA. Polyamines are essential for synthesis of 2-ricinoleoyl phosphatidic acid in developing castor seeds.

  20. Oxidation and inactivation of SERCA by selective reaction of cysteine residues with amino acid peroxides.

    PubMed

    Dremina, Elena S; Sharov, Victor S; Davies, Michael J; Schöneich, Christian

    2007-10-01

    The oxidative modification of proteins plays an important role in a wide range of pathological processes and aging. Proteins are modified by numerous biologic oxidants including hydrogen peroxide, peroxynitrite, singlet oxygen, and oxygen- and nitrogen-centered radicals. More recently, an additional class of physiologically important oxidants has been identified, peptide and protein peroxides. The latter react quite rapidly and selectively with protein cysteine residues. The sarco/endoplasmic reticulum Ca-ATPase (SERCA) is reversibly regulated through NO-dependent S-glutathiolation of specific cysteine residues. The irreversible oxidation of these cysteine residues could, therefore, impair NO-dependent muscle relaxation. Here, we show that specific protein-derived (amino acid) peroxides react selectively with a subset of the 22 reduced cysteine residues of SERCA1, including a peptide-containing Cys674 and Cys675, where Cys674 (in SERCA2) represents one of the targets for NO-dependent S-glutathiolation. Out of 11 tested amino acid, peptide, and protein peroxides, those derived from free tryptophan and free tyrosine showed the highest reactivity towards SERCA, while no oxidation under similar experimental conditions was detected through hydrogen peroxide. Among the peroxides from tryptophan, those of free tryptophan showed a significantly higher reactivity as compared to those from N- and C-terminally blocked tryptophan. Quantitative HPLC-MS/MS analysis demonstrated that the highest reactivity of the tryptophan-derived peroxides was observed for Cys774 and Cys938, cysteine residues, which are embedded within the transmembrane domains of SERCA1. This unusual reactivity of transmembrane domains cannot be solely rationalized by the hydrophobicity of the oxidant, as the peroxide from dl-tryptophan shows considerable higher reactivity as compared to the one derived from N-acetyl-tryptophan methyl ester. Our data demonstrate a potential role of peptide- and protein

  1. Determination of free acidic and alkaline residues of protein via moving reaction boundary titration in microdevice electrophoresis.

    PubMed

    Wang, Hou-yu; Li, Si; Tang, Yun-yun; Dong, Jing-yu; Fan, Liu-yin; Cao, Cheng-xi

    2013-06-21

    As two important physico-chemical parameters, the acidic and alkaline residues of protein are of evident significance for the evaluation of protein properties and the design of relevant separation and analysis. However, there is still no electrophoretic method used for the direct detection of free acidic and alkaline residues of protein. Herein, we developed the concepts of moving reaction boundary (MRB) and MRB titration, relevant MRB titration theory, and the method of microdevice electrophoresis for the determination of free acidic and alkaline residues of protein. In the MRB titration, the boundary was created with acid or alkali and target protein immobilized via highly cross-linked polyacrylamide gel (PAG). It was theoretically revealed that the number of free acidic or alkaline residues of protein was as a function of MRB displacement in the electrophoretic titration system. As a proof of concept, seven model proteins were chosen for the determination of acidic or alkaline residues of protein via MRB titration. The results showed that the numbers of free acidic and alkaline residues of proteins detected were in good agreement with those obtained from the relevant amino sequences in the NCBI database, demonstrating the feasibility of the developed concept, theory and technique. The general methodology of MRB titration has potential application for inexpensive, facilitative and informative protein structure analysis of free acidic or alkaline residues of protein.

  2. Mutagenesis of conserved amino acids of Helicobacter pylori fur reveals residues important for function.

    PubMed

    Carpenter, Beth M; Gancz, Hanan; Benoit, Stéphane L; Evans, Sarah; Olsen, Cara H; Michel, Sarah L J; Maier, Robert J; Merrell, D Scott

    2010-10-01

    The ferric uptake regulator (Fur) of the medically important pathogen Helicobacter pylori is unique in that it has been shown to function as a repressor both in the presence of an Fe2+ cofactor and in its apo (non-Fe2+-bound) form. However, virtually nothing is known concerning the amino acid residues that are important for Fur functioning. Therefore, mutations in six conserved amino acid residues of H. pylori Fur were constructed and analyzed for their impact on both iron-bound and apo repression. In addition, accumulation of the mutant proteins, protein secondary structure, DNA binding ability, iron binding capacity, and the ability to form higher-order structures were also examined for each mutant protein. While none of the mutated residues completely abrogated the function of Fur, we were able to identify residues that were critical for both iron-bound and apo-Fur repression. One mutation, V64A, did not alter regulation of any target genes. However, each of the five remaining mutations showed an effect on either iron-bound or apo regulation. Of these, H96A, E110A, and E117A mutations altered iron-bound Fur regulation and were all shown to influence iron binding to different extents. Additionally, the H96A mutation was shown to alter Fur oligomerization, and the E110A mutation was shown to impact oligomerization and DNA binding. Conversely, the H134A mutant exhibited changes in apo-Fur regulation that were the result of alterations in DNA binding. Although the E90A mutant exhibited alterations in apo-Fur regulation, this mutation did not affect any of the assessed protein functions. This study is the first for H. pylori to analyze the roles of specific amino acid residues of Fur in function and continues to highlight the complexity of Fur regulation in this organism.

  3. Natural populations of lactic acid bacteria isolated from vegetable residues and silage fermentation.

    PubMed

    Yang, J; Cao, Y; Cai, Y; Terada, F

    2010-07-01

    Natural populations of lactic acid bacteria (LAB) and silage fermentation of vegetable residues were studied. Fifty-two strains of LAB isolated from cabbage, Chinese cabbage, and lettuce residues were identified and characterized. The LAB strains were gram-positive and catalase-negative bacteria, which were divided into 6 groups (A to F) according to morphological and biochemical characteristics. The strains in group A were rods that did not produce gas from glucose and formed the d and l isomers of lactate. Groups B and C were homofermentative cocci that formed l-lactic acid. Groups D, E, and F were heterofermentative cocci that formed d-lactic acid. Based on 16S rDNA gene sequence analysis, group A to F strains were identified as Lactobacillus plantarum, Lactococcus piscium, Lactococcus lactis, Leuconostoc citreum, Weissella soli and Leuconostoc gelidum, respectively. The prevalent LAB, predominantly homofermentative lactobacilli, consisted of Lactobacillus plantarum (34.6%), Weissella soli (19.2%), Leuconostoc gelidum (15.4%), Leuconostoc citreum (13.5%), Lactococcus lactis (9.6%), and Lactococcus piscium (7.7%). Lactobacillus plantarum was the dominant member of the LAB population in 3 types of vegetable residues. These vegetable residues contained a high level of crude protein (20.2 to 28.4% of dry matter). These silages prepared by using a small-scale fermentation system were well preserved, with low pH and a relatively high content of lactate. This study suggests that the vegetable residues contain abundant LAB species and nutrients, and that they could be well preserved by making silage, which is a potentially good vegetable protein source for livestock diets.

  4. Comparison between liquid and solid acids catalysts on reducing sugars conversion from furfural residues via pretreatments.

    PubMed

    Lin, Keying; Ma, Baojun; Sun, Yuan; Liu, Wanyi

    2014-09-01

    Liquid sulphuric acid is adopted and compared with carbon-based sulfonated solid acids (coal tar-based and active carbon-based) for furfural residues conversion into reducing sugars. The optimum hydrolysis conditions of liquid acid are at 4% of sulphuric acid, 25:1 of liquid and solid ratio, 175°C of reaction temperature and 120 min of reaction time. The reducing sugar yields are reached over 60% on liquid acid via NaOH/H2O2, NaOH/microwave and NaOH/ultrasonic pretreatments, whereas only over 30% on solid acids. The TOFs (turnover number frequency) via NaOH/H2O2 pretreatments are 0.093, 0.020 and 0.023 h(-1) for liquid sulphuric acid, coal tar-based and active carbon-based solid acids catalysts, respectively. Considering the efficiency, cost and environment factors, the liquid and solid acids have their own advantages of potential commercial application values.

  5. Fatty acid metabolism during maturation affects glucose uptake and is essential to oocyte competence.

    PubMed

    Paczkowski, M; Schoolcraft, W B; Krisher, R L

    2014-10-01

    Fatty acid β-oxidation (FAO) is essential for oocyte maturation in mice. The objective of this study was to determine the effect of etomoxir (a FAO inhibitor; 100 μM), carnitine (1 mM), and palmitic acid (1 or 100 μM) during maturation on metabolism and gene expression of the oocyte and cumulus cells, and subsequent embryo development in the mouse. Carnitine significantly increased embryo development, while there was a decrease in development following maturation with 100 μM palmitic acid or etomoxir (P<0.05) treatment. Glucose consumption per cumulus-oocyte complex (COC) was decreased after treatment with carnitine and increased following etomoxir treatment (P<0.05). Intracellular oocyte lipid content was decreased after carnitine or etomoxir exposure (P<0.05). Abundance of Slc2a1 (Glut1) was increased after etomoxir treatment in the oocyte and cumulus cells (P<0.05), suggesting stimulation of glucose transport and potentially the glycolytic pathway for energy production when FAO is inhibited. Abundance of carnitine palmitoyltransferase 2 (Cpt2) tended to increase in oocytes (P=0.1) after treatment with 100 μM palmitic acid and in cumulus cells after exposure to 1 μM palmitic acid (P=0.07). Combined with carnitine, 1 μM palmitic acid increased the abundance of Acsl3 (P<0.05) and Cpt2 tended to increase (P=0.07) in cumulus cells, suggesting FAO was increased during maturation in response to stimulators and fatty acids. In conclusion, fatty acid and glucose metabolism are related to the mouse COC, as inhibition of FAO increases glucose consumption. Stimulation of FAO decreases glucose consumption and lipid stores, positively affecting subsequent embryo development, while an overabundance of fatty acid or reduced FAO negatively affects oocyte quality.

  6. Studies on the biochemical composition, energetics and essential amino acids of three mudskippers in Xiamen Harbour

    NASA Astrophysics Data System (ADS)

    Jun, Wang; Yong-Quan, Su

    1995-12-01

    Measurements were made on the contents of protein, lipid, glycogen (PLG) and water, and on caloric values and amino acids, in muscle of three mudskippers Periophthalmus cantonensis, Scarteiaos viridis and Boleophthalmus pectinirostris collected from Haicang, Xiamen. The essential amino acids (EAA) for these fishes were also studied with radioisotopic trace method. The results showed: (1) The content of each component in tested fish muscles differed slightly, and protein was the most important component making up from 6.685% to 9.891% of the wet weight (about 44.21%-50.45% of dry weight); (2) Energy calculated from the sum of protein, lipid and glycogen in wet muscle was low (<4.3kJ/g) in these fishes, especially in B. pectinirostris (<3.1 kJ/g); the ratios of energy to protein content ( E/P) also were low (<39.873-45.535kJ/g); (3) Seventeen amino acids were determined in these three fishes. The content of the same amino acid (among the seventeen) tested in different species and sexes varied slightly. The amounts of methionine, phenylalanine lysine, arginine, histidine, threonine isoleucine and leucine which are indispensable for the needs of human beings and animals were relatively high, accounting for 47.35%-48.06% of the total amino acid content. (4) Leucine, isoleucine, arginine, lysine, phenylalanine, tryptophan, methionine, histidine, threonine, and valine, are essential in the diet of the three mudskippers as the radioisotopic trace method using D-[U-14C]-glucose showed little or no radioactivity was incorporated into these ten amino acids.

  7. Studies on the biochemical composition, energetics and essential amino acids of three mudskippers in Xiamen Harbour

    NASA Astrophysics Data System (ADS)

    Wang, Jun; Su, Yong-Quan

    1995-12-01

    Measurements were made on the contents of protein, lipid, glycogen (PLG) and water, and on caloric values and amino acids, in muscle of three mudskippers Periophthalmus cantonensis, Scarteiaos viridis and Boleophthalmus pectinirostris collected from Haicang, Xiamen. The essential amino acids (EAA) for these fishes were also studied with radioisotopic trace method. The results showed: (1) The content of each component in tested fish muscles differed slightly, and protein was the most important component making up from 6.685% to 9.891% of the wet weight (about 44.21% 50.45% of dry weight); (2) Energy calculated from the sum of protein, lipid and glycogen in wet muscle was low (<4.3kJ/g) in these fishes, especially in B. pectinirostris (<3.1 kJ/g); the ratios of energy to protein content ( E/P) also were low (<39.873 45.535kJ/g); (3) Seventeen amino acids were determined in these three fishes. The content of the same amino acid (among the seventeen) tested in different species and sexes varied slightly. The amounts of methionine, phenylalanine lysine, arginine, histidine, threonine isoleucine and leucine which are indispensable for the needs of human beings and animals were relatively high, accounting for 47.35% 48.06% of the total amino acid content. (4) Leucine, isoleucine, arginine, lysine, phenylalanine, tryptophan, methionine, histidine, threonine, and valine, are essential in the diet of the three mudskippers as the radioisotopic trace method using D-[U-14C]-glucose showed little or no radioactivity was incorporated into these ten amino acids.

  8. Autistic Children Exhibit Decreased Levels of Essential Fatty Acids in Red Blood Cells

    PubMed Central

    Brigandi, Sarah A.; Shao, Hong; Qian, Steven Y.; Shen, Yiping; Wu, Bai-Lin; Kang, Jing X.

    2015-01-01

    Omega-6 (n-6) and omega-3 (n-3) polyunsaturated fatty acids (PUFA) are essential nutrients for brain development and function. However, whether or not the levels of these fatty acids are altered in individuals with autism remains debatable. In this study, we compared the fatty acid contents between 121 autistic patients and 110 non-autistic, non-developmentally delayed controls, aged 3–17. Analysis of the fatty acid composition of red blood cell (RBC) membrane phospholipids showed that the percentage of total PUFA was lower in autistic patients than in controls; levels of n-6 arachidonic acid (AA) and n-3 docosahexaenoic acid (DHA) were particularly decreased (p < 0.001). In addition, plasma levels of the pro-inflammatory AA metabolite prostaglandin E2 (PGE2) were higher in a subset of the autistic participants (n = 20) compared to controls. Our study demonstrates an alteration in the PUFA profile and increased production of a PUFA-derived metabolite in autistic patients, supporting the hypothesis that abnormal lipid metabolism is implicated in autism. PMID:25946342

  9. Anthelmintic efficacy of cinnamaldehyde and cinnamic acid from cortex cinnamon essential oil against Dactylogyrus intermedius.

    PubMed

    Ling, Fei; Jiang, Chao; Liu, Guanglu; Li, Mingshuang; Wang, Gaoxue

    2015-12-01

    Utilization of chemical pesticide to control monogenean diseases is often restricted in many countries due to the development of pesticide resistance and concerns of chemical residues and environmental contamination. Thus, the use of antiparasitic agents from plants has been explored as a possible way for controlling monogenean infections. Extracts from Cinnamomum cassia were investigated under in vivo conditions against Dactylogyrus intermedius in goldfish. The two bioactive compounds, cinnamaldehyde and cinnamic acid, were identified using nuclear magnetic resonance and electrospray ionization mass spectrometry. The 48 h median effective concentrations (EC(50)) for these compounds against D. intermedius were 0·57 and 6·32 mg L(-1), respectively. The LD(50) of cinnamaldehyde and cinnamic acid were 13·34 and 59·66 mg L(-1) to goldfish in 48 h acute toxicity tests, respectively. These data confirm that cinnamaldehyde is effective against D. intermedius, and the cinnamaldehyde exhibits potential for the development of a candidate antiparasitic agent.

  10. Important amino acid residues of hexachlorocyclohexane dehydrochlorinases (LinA) for enantioselective transformation of hexachlorocyclohexane isomers.

    PubMed

    Shrivastava, Nidhi; Macwan, Ankit S; Kohler, Hans-Peter E; Kumar, Ashwani

    2017-03-01

    LinA-type1 and LinA-type2 are two well-characterized variants of the enzyme 'hexachlorocyclohexane (HCH)-dehydrochlorinase'. They differ from each other at ten amino acid positions and exhibit differing enantioselectivity for the transformation of the (-) and (+) enantiomers of α-HCH. Amino acids responsible for this enantioselectivity, however, are not known. An in silico docking analysis identified four amino acids (K20, L96, A131, and T133) in LinA-type1 that could be involved in selective binding of the substrates. Experimental studies with constructed mutant enzymes revealed that a combined presence of three amino acid changes in LinA-type1, i.e. K20Q, L96C, and A131G, caused a reversal in its preference from the (-) to the (+) enantiomer of α-HCH. This preference was enhanced by the additional amino acid change T133 M. Presence of these four changes also caused the reversal of enantioselectivity of LinA-type1 for δ-HCH, and β-, γ-, and δ-pentachlorocyclohexens. Thus, the residues K20, L96, A131, and T133 in LinA-type1 and the residues Q20, C96, G131, and M133 in LinA-type 2 appear to be important determinants for the enantioselectivity of LinA enzymes.

  11. Lactobacillus plantarum BL011 cultivation in industrial isolated soybean protein acid residue.

    PubMed

    Coghetto, Chaline Caren; Vasconcelos, Carolina Bettker; Brinques, Graziela Brusch; Ayub, Marco Antônio Záchia

    In this study, physiological aspects of Lactobacillus plantarum BL011 growing in a new, all-animal free medium in bioreactors were evaluated aiming at the production of this important lactic acid bacterium. Cultivations were performed in submerged batch bioreactors using the Plackett-Burman methodology to evaluate the influence of temperature, aeration rate and stirring speed as well as the concentrations of liquid acid protein residue of soybean, soy peptone, corn steep liquor, and raw yeast extract. The results showed that all variables, except for corn steep liquor, significantly influenced biomass production. The best condition was applied to bioreactor cultures, which produced a maximal biomass of 17.87gL(-1), whereas lactic acid, the most important lactic acid bacteria metabolite, peaked at 37.59gL(-1), corresponding to a productivity of 1.46gL(-1)h(-1). This is the first report on the use of liquid acid protein residue of soybean medium for L. plantarum growth. These results support the industrial use of this system as an alternative to produce probiotics without animal-derived ingredients to obtain high biomass concentrations in batch bioreactors.

  12. Critical amino acid residues of maurocalcine involved in pharmacology, lipid interaction and cell penetration.

    PubMed

    Mabrouk, Kamel; Ram, Narendra; Boisseau, Sylvie; Strappazzon, Flavie; Rehaim, Amel; Sadoul, Rémy; Darbon, Hervé; Ronjat, Michel; De Waard, Michel

    2007-10-01

    Maurocalcine (MCa) is a 33-amino acid residue peptide that was initially identified in the Tunisian scorpion Scorpio maurus palmatus. This peptide triggers interest for three main reasons. First, it helps unravelling the mechanistic basis of Ca(2+) mobilization from the sarcoplasmic reticulum because of its sequence homology with a calcium channel domain involved in excitation-contraction coupling. Second, it shows potent pharmacological properties because of its ability to activate the ryanodine receptor. Finally, it is of technological value because of its ability to carry cell-impermeable compounds across the plasma membrane. Herein, we characterized the molecular determinants that underlie the pharmacological and cell-penetrating properties of maurocalcine. We identify several key amino acid residues of the peptide that will help the design of cell-penetrating analogues devoid of pharmacological activity and cell toxicity. Close examination of the determinants underlying cell penetration of maurocalcine reveals that basic amino acid residues are required for an interaction with negatively charged lipids of the plasma membrane. Maurocalcine analogues that penetrate better have also stronger interaction with negatively charged lipids. Conversely, less effective analogues present a diminished ability to interact with these lipids. These findings will also help the design of still more potent cell penetrating analogues of maurocalcine.

  13. Study on effect of lomefloxacin on human holo-transferrin in the presence of essential and nonessential amino acids: Spectroscopic and molecular modeling approaches.

    PubMed

    Marouzi, Somaye; Sharifi Rad, Atena; Beigoli, Sima; Teimoori Baghaee, Parisa; Assaran Darban, Reza; Chamani, Jamshidkhan

    2017-04-01

    The purpose of this study was to determine how lomefloxacin (LMF) interacts with human holo-transferrin (HTF) in the presence of two kinds of essential and nonessential amino acids. The investigations were carried out by fluorescence spectroscopy, zeta potential and molecular modeling techniques under imitated physiological conditions. We were able to determine the number of binding sites, the drug binding affinity to HTF in the presence of essential and nonessential amino acids and the quenching source of HTF. The interaction between HTF with LMF suggested that the microenvironment of the Trp residues was altered causing a strong static fluorescence quenching in the binary and ternary systems. The results pointed at the formation of a complex in the binary and ternary systems which caused an enhancement of the RLS intensity that was analyzed using synchronous fluorescence spectroscopy. The density functional theory (DFT) was employed to determine the amino acid residues on HTF that interacted with LMF. Also, Steric and van der Waals forces as well as the contribution of small amounts of hydrogen bonds were stronger or Tyr 71 in chain (b) than for 128 Trp in chain (a) of HTF.

  14. Acetic Acid Can Catalyze Succinimide Formation from Aspartic Acid Residues by a Concerted Bond Reorganization Mechanism: A Computational Study

    PubMed Central

    Takahashi, Ohgi; Kirikoshi, Ryota; Manabe, Noriyoshi

    2015-01-01

    Succinimide formation from aspartic acid (Asp) residues is a concern in the formulation of protein drugs. Based on density functional theory calculations using Ace-Asp-Nme (Ace = acetyl, Nme = NHMe) as a model compound, we propose the possibility that acetic acid (AA), which is often used in protein drug formulation for mildly acidic buffer solutions, catalyzes the succinimide formation from Asp residues by acting as a proton-transfer mediator. The proposed mechanism comprises two steps: cyclization (intramolecular addition) to form a gem-diol tetrahedral intermediate and dehydration of the intermediate. Both steps are catalyzed by an AA molecule, and the first step was predicted to be rate-determining. The cyclization results from a bond formation between the amide nitrogen on the C-terminal side and the side-chain carboxyl carbon, which is part of an extensive bond reorganization (formation and breaking of single bonds and the interchange of single and double bonds) occurring concertedly in a cyclic structure formed by the amide NH bond, the AA molecule and the side-chain C=O group and involving a double proton transfer. The second step also involves an AA-mediated bond reorganization. Carboxylic acids other than AA are also expected to catalyze the succinimide formation by a similar mechanism. PMID:25588215

  15. Camphorquinone-10-sulfonic acid and derivatives: convenient reagents for reversible modification of arginine residues

    SciTech Connect

    Pande, C.S.; Pelzig, M.; Glass, J.D.

    1980-02-01

    Camphorquinone-10-sulfonic acid hydrate was prepared by the action of selenous acid on camphor-10-sulfonic acid. Camphorquinone-10-sulfonylnorleucine was prepared either from the sulfonic acid via the sulfonyl chloride or by selenous acid oxidation of camphor-10-sulfonylnorleucine. These reagents are useful for specific, reversible modification of the guanidino groups of arginine residues. Camphorquinonsulfonic acid is a crystalline water-soluble reagent that is especially suitable for use with small arginine-containing molecules, because the sulfonic acid group of the reagent is a convenient handle for analytical and preparative separation of products. Camphorquinonesulfonylnorleucine is more useful for work with large polypeptides and proteins, because hydrolysates of modified proteins may be analyzed for norleucine to determine the extent of arginine modification. The adducts of the camphorquinone derivatives with the guanidino group are stable to 0.5 M hydroxylamine solutions at pH 7, the recommended conditions for cleavage of the corresponding cyclohexanedione adducts. At pH 8-9 the adducts of the camphorquinone derivatives with the guanidino group are cleaved by o-phenylenediamine. The modification and regeneration of arginine, of the dipeptide arginylaspartic acid, of ribonuclease S-peptide, and of soybean trypsin inhibitor are presented as demonstrations of the use of the reagents.The use of camphorquinonesulfonyl chloride to prepare polymers containing arginine-specific ligands is discussed.

  16. Amino acid residues Leu135 and Tyr236 are required for RNA binding activity of CFIm25 in Entamoeba histolytica.

    PubMed

    Ospina-Villa, Juan David; Zamorano-Carrillo, Absalom; Lopez-Camarillo, Cesar; Castañon-Sanchez, Carlos A; Soto-Sanchez, Jacqueline; Ramirez-Moreno, Esther; Marchat, Laurence A

    2015-08-01

    Pre-mRNA 3' end processing in the nucleus is essential for mRNA stability, efficient nuclear transport, and translation in eukaryotic cells. In Human, the cleavage/polyadenylation machinery contains the 25 kDa subunit of the Cleavage Factor Im (CFIm25), which specifically recognizes two UGUA elements and regulates the assembly of polyadenylation factors, poly(A) site selection and polyadenylation. In Entamoeba histolytica, the protozoan parasite responsible for human amoebiasis, EhCFIm25 has been reported as a RNA binding protein that interacts with the Poly(A) Polymerase. Here, we follow-up with the study of EhCFIm25 to characterize its interaction with RNA. Using in silico strategy, we identified Leu135 and Tyr236 in EhCFIm25 as conserved amino acids among CFIm25 homologues. We therefore generated mutant EhCFIm25 proteins to investigate the role of these residues for RNA interaction. Results showed that RNA binding activity was totally abrogated when Leu135 and Tyr236 were replaced with Ala residue, and Tyr236 was changed for Phe. In contrast, RNA binding activity was less affected when Leu135 was substituted by Thr. Our data revealed for the first time -until we know-the functional relevance of the conserved Leu135 and Tyr236 in EhCFIm25 for RNA binding activity. They also gave some insights about the possible chemical groups that could be interacting with the RNA molecule.

  17. Diverse amino acid residues function within the type 1 peroxisomal targeting signal. Implications for the role of accessory residues upstream of the type 1 peroxisomal targeting signal.

    PubMed

    Mullen, R T; Lee, M S; Flynn, C R; Trelease, R N

    1997-11-01

    The purpose of this study was to determine whether the plant type 1 peroxisomal targeting signal (PTS1) utilizes amino acid residues that do not strictly adhere to the serine-lysine-leucine (SKL) motif (small-basic-hydrophobic residues). Selected residues were appended to the C terminus of chloramphenicol acetyltransferase (CAT) and were tested for their ability to target CAT fusion proteins to glyoxysomes in tobacco (Nicotiana tabacum L.) cv Bright Yellow 2 suspension-cultured cells. CAT was redirected from the cytosol into glyoxysomes by a wide range of residues, i.e. A/C/G/S/T-H/K/ L/N/R-I/L/M/Y. Although L and N at the -2 position (-SLL, -ANL) do not conform to the SKL motif, both functioned, but in a temporally less-efficient manner. Other SKL divergent residues, however, did not target CAT to glyoxysomes, i.e. F or P at the -3 position (-FKL, -PKL), S or T at the -2 position (-SSI, STL), or D at the -1 position (-SKD). The targeting inefficiency of CAT-ANL could be ameliorated when K was included at the -4 position (-KANL). In summary, the plant PTS1 mostly conforms to the SKL motif. For those PTS1s that possess nonconforming residue(s), other residues upstream of the PTS1 appear to function as accessory sequences that enhance the temporal efficiency of peroxisomal targeting.

  18. Nitrogen retention of young men who consumed selection patterns of essential amino acids at a constant nitrogen intake.

    PubMed

    Brewer, M F; Halvorson, J D; Calrk, H E

    1978-05-01

    Six patterns of essential amino acids were devised to represent different sources or combinations of protein based on a daily intake of 6.0 g of nitrogen from these sources. In each diet, cereals furnished 70% and a specially designed amino acid mixture 30% of the total nitrogen. Nitrogen retention of young men who consumed amino acids equivalent to combinations of rice and soy or egg and potato did not differ from the pattern of egg, and these patterns were superior to a combination of rice and wheat; egg also was superior to corn plus beans and wheat plus milk. Relative amounts and proportions of essential amino acids could be modified without depressing nitrogen retention until one amino acid became limiting or the pattern became imbalanced. Therefore, more than one pattern of amino acids should be recognized as useful for adult human subjects; both minimal and total amounts of essential amino acids need to be considered.

  19. Removal of copper from acid wastewater of bioleaching by adsorption onto ramie residue and uptake by Trichoderma viride.

    PubMed

    Wang, Buyun; Wang, Kai

    2013-05-01

    A continuous batch bioleaching was built to realize the bioleaching of sewage sludge in large scale. In the treatment, heavy metal in acid wastewater of bioleaching was removed by adsorption onto ramie residue. Then, acid wastewater was reused in next bioleaching batch. In this way, most time and water of bioleaching was saved and leaching efficiency of copper, lead and chromium kept at a high level in continuous batch bioleaching. It was found that residual heavy metal in sewage sludge is highly related to that in acid wastewater after bioleaching. To get a high leaching efficiency, concentration of heavy metal in acid wastewater should be low. Adsorption of copper from acid wastewater onto ramie residue can be described by pseudo first-order kinetics equation and Freundlich isotherm model. Trichoderma viride has the potential to be used for the concentration and recovery of heavy metal adsorbed onto ramie residue.

  20. Extension of UNRES force field to treat polypeptide chains with D-amino-acid residues

    PubMed Central

    Sieradzan, Adam K.; Hansmann, Ulrich H.E.; Scheraga, Harold A.; Liwo, Adam

    2013-01-01

    Coarse-grained force fields for protein simulations are usually designed and parameterized to treat proteins composed of natural L-amino-acid residues. However, D-amino-acid residues occur in bacterial, fungal (e.g., gramicidins), as well as human-designed proteins. For this reason, we have extended the UNRES coarse-grained force field developed in our laboratory to treat systems with D-amino-acid residues. We developed the respective virtual-bond-torsional and double-torsional potentials for rotation about the Cα · · · Cα virtual-bond axis and two consecutive Cα · · · Cα virtual-bond axes, respectively, as functions of virtual-bond-dihedral angles γ. In turn, these were calculated as potentials of mean force (PMFs) from the diabatic energy surfaces of terminally-blocked model compounds for glycine, alanine, and proline. The potential-energy surfaces were calculated by using the ab initio method of molecular quantum mechanics at the Møller-Plesset (MP2) level of theory and the 6-31G(d,p) basis set, with the rotation angles of the peptide groups about Ci-1α⋯Ciα(λ(1)) and Ciα⋯Ci+1α(λ(2)) used as variables, and the energy was minimized with respect to the remaining degrees of freedom. The PMFs were calculated by numerical integration for all pairs and triplets with all possible combinations of types (glycine, alanine, and proline) and chirality (D or L); however, symmetry relations reduce the number of non-equivalent torsional potentials to 13 and the number of double-torsional potentials to 63 for a given C-terminal blocking group. Subsequently, one- (for torsional) and two-dimensional (for double-torsional potentials) Fourier series were fitted to the PMFs to obtain analytical expressions. It was found that the torsional potentials of the x-Y and X-y types, where X and Y are Ala or Pro, respectively, and a lowercase letter denotes D-chirality, have global minima for small absolute values of γ, accounting for the double-helical structure of

  1. Essential and long-chain polyunsaturated fatty acid status and fatty acid composition of breast milk of lactating adolescents.

    PubMed

    Meneses, Flávia; Torres, Alexandre G; Trugo, Nádia M F

    2008-11-01

    The aims of the present study were to evaluate essential fatty acids (EFA) and long-chain PUFA (LCPUFA) status in lactating adolescents and its association with breast milk composition. Healthy nursing adolescents from Rio de Janeiro, Brazil (n 30; 14-19 years; 30-120 d postpartum), exclusively or predominantly breast-feeding, participated in this study. Breast milk and blood samples were collected after overnight fasting. Fatty acid composition of breast milk, erythrocyte membrane (EM) and plasma NEFA were determined by GC. Indices of fatty acid status (mean melting point (MMP); EFA status index; DHA status indices, 22 : 5n-6:22 : 4n-6 and 22 : 6n-3:22 : 5n-6 ratios) were calculated from EM fatty acid composition. Dietary intake of n-3 fatty acids was low when compared with current recommendations for lactating women. MMP was associated with indices of DHA status, some individual fatty acids in EM and years post-menarche and weeks postpartum, suggesting the use of erythrocyte MMP as a possible comprehensive biochemical marker of LCPUFA status in this physiological condition. The DHA status of lactating adolescents and their milk DHA concentrations were similar to the values of Brazilian lactating adults, but lower compared with the values of lactating adults from other countries. Therefore, these lactating adolescents were apparently not disadvantaged, as compared with the Brazilian adults, when EM and breast milk fatty acid composition were considered. In general, PUFA in milk from adolescents presented few associations with their concentrations in plasma NEFA and with maternal status. However, milk DHA was associated with maternal LCPUFA and DHA states.

  2. Chlorogenic acid content, essential oil compositions, and in vitro antioxidant activities of Chromolaena odorata leaves

    PubMed Central

    Pitakpawasutthi, Yamon; Thitikornpong, Worathat; Palanuvej, Chanida; Ruangrungsi, Nijsiri

    2016-01-01

    Chromolaena odorata (L.) R. M. King and H. Rob. is a Thai medicinal plant used for the treatment of wounds, rashes, diabetes, and insect repellent. The leaves of C. odorata were collected from 10 different sources throughout Thailand. The chemical constituents of essential oils were hydro-distilled from the leaves and were analyzed by gas chromatography-mass spectrometry. Chlorogenic acid contents were determined by thin-layer chromatography (TLC) - densitometry with winCATS software and TLC image analysis with ImageJ software. The TLC plate was developed in the mobile phase that consisted of ethyl acetate:water:formic acid (17:3:2). Antioxidant activities were examined by 1,1-diphenyl-2-picryl hydrazyl (DPPH) radical scavenging and β-carotene bleaching assays. C. odorata essential oil has shown the major components of pregeijerene, dauca-5, 8-diene, (E)-caryophyllene, β-pinene, and α-pinene. The chlorogenic acid content of C. odorata leaves was determined by TLC-densitometry and TLC image analysis. Results have shown that TLC-densitometry and TLC image analysis method were not statistically significantly different. DPPH radical scavenging and β-carotene bleaching assays of ethanolic extract of C. odorata leaves showed its antioxidant potential. PMID:27144150

  3. Chlorogenic acid content, essential oil compositions, and in vitro antioxidant activities of Chromolaena odorata leaves.

    PubMed

    Pitakpawasutthi, Yamon; Thitikornpong, Worathat; Palanuvej, Chanida; Ruangrungsi, Nijsiri

    2016-01-01

    Chromolaena odorata (L.) R. M. King and H. Rob. is a Thai medicinal plant used for the treatment of wounds, rashes, diabetes, and insect repellent. The leaves of C. odorata were collected from 10 different sources throughout Thailand. The chemical constituents of essential oils were hydro-distilled from the leaves and were analyzed by gas chromatography-mass spectrometry. Chlorogenic acid contents were determined by thin-layer chromatography (TLC) - densitometry with winCATS software and TLC image analysis with ImageJ software. The TLC plate was developed in the mobile phase that consisted of ethyl acetate:water:formic acid (17:3:2). Antioxidant activities were examined by 1,1-diphenyl-2-picryl hydrazyl (DPPH) radical scavenging and β-carotene bleaching assays. C. odorata essential oil has shown the major components of pregeijerene, dauca-5, 8-diene, (E)-caryophyllene, β-pinene, and α-pinene. The chlorogenic acid content of C. odorata leaves was determined by TLC-densitometry and TLC image analysis. Results have shown that TLC-densitometry and TLC image analysis method were not statistically significantly different. DPPH radical scavenging and β-carotene bleaching assays of ethanolic extract of C. odorata leaves showed its antioxidant potential.

  4. Crystal structure of FadD32, an enzyme essential for mycolic acid biosynthesis in mycobacteria.

    PubMed

    Li, Wenjuan; Gu, Shoujin; Fleming, Joy; Bi, Lijun

    2015-12-02

    Fatty acid degradation protein D32 (FadD32), an enzyme required for mycolic acid biosynthesis and essential for mycobacterial growth, has recently been identified as a valid and promising target for anti-tuberculosis drug development. Here we report the crystal structures of Mycobacterium smegmatis FadD32 in the apo and ATP-bound states at 2.4 Å and 2.25 Å resolution, respectively. FadD32 consists of two globular domains connected by a flexible linker. ATP binds in a cleft at the interface between the N- and C-terminal domains and its binding induces significant local conformational changes in FadD32. The binding sites of meromycolic acid and phosphopantetheine are identified by structural comparison with other members of the adenylating enzyme superfamily. These results will improve our understanding of the catalytic mechanism of FadD32 and help in the design of inhibitors of this essential enzyme.

  5. Fatty Acid Flippase Activity Of UCP2 Is Essential For Its Proton Transport In Mitochondria

    PubMed Central

    Berardi, Marcelo J.; Chou, James J.

    2014-01-01

    SUMMARY Modulation of cellular energy expenditure is fundamental to normal and pathological cell growth and differentiation. Mitochondria stores energy as a proton gradient across their inner membrane. Uncoupling proteins (UCPs) can dissipate the gradient to produce heat or regulate metabolite fluxes. UCP-mediated proton currents require fatty acids (FA) and are blocked by nucleotides, but the molecular basis of these processes is unknown. We find, by nuclear magnetic resonance and functional mutagenesis, that UCP2 can bind FA laterally thru its peripheral site, and this intramembrane molecular recognition is essential for UCP2-catalyzed FA flipping across the membrane, which in turn is essential for proton translocation. The antagonist GDP binds inside the UCP2 cavity and perturbs its conformation, which can displace FA from the peripheral site as a mean of inhibiting proton currents. Our data provide a biophysical perspective of the intricate interplay of UCPs, FA, and nucleotides in determining proton fluxes in mitochondria. PMID:25127353

  6. Mobilization of Cr(VI) from chromite ore processing residue through acid treatment.

    PubMed

    Tinjum, James M; Benson, Craig H; Edil, Tuncer B

    2008-02-25

    Batch leaching studies on chromite ore processing residue (COPR) were performed using acids to investigate leaching of hexavalent chromium, Cr(VI), with respect to particle size, reaction time, and type of acid (HNO(3) and H(2)SO(4)). Aqueous Cr(VI) is maximized at approximately 0.04 mol Cr(VI) per kg of dry COPR at pH 7.6-8.1. Cr(VI) mobilized more slowly for larger particles, and the pH increased with time and increased more rapidly for smaller particles, suggesting that rate limitations occur in the solid phase. With H(2)SO(4), the pH stabilized at a higher value (8.8 for H(2)SO(4) vs. 8.0 for HNO(3)) and more rapidly (16 h vs. 30 h), and the differences in pH for different particle sizes were smaller. The acid neutralization capacity (ANC) of COPR is very large (8 mol HNO(3) per kg of dry COPR for a stable eluate pH of 7.5). Changes to the elemental and mineralogical composition and distribution in COPR particles after mixing with acid indicate that Cr(VI)-bearing solids dissolved. However, concentrations of Cr(VI) >2800 mg kg(-1) (>50% of the pre-treatment concentration) were still found after mixing with acid, regardless of the particle size, reaction time, or type of acid used. The residual Cr(VI) appears to be partially associated with poorly-ordered Fe and Al oxyhydroxides that precipitated in the interstitial areas of COPR particles. Remediation strategies that use HNO(3) or H(2)SO(4) to neutralize COPR or to maximize Cr(VI) in solution are likely to require extensive amounts of acid, may not mobilize all of the Cr(VI), and may require extended contact time, even under well-mixed conditions.

  7. The Role of Essential Fatty Acids in Anorexia Nervosa and Obesity.

    PubMed

    Yehuda, Shlomo; Rabinovitz, Sharon

    2016-09-09

    The two basic questions in food intake study are what we eat, and how much do we eat. Most research is directed toward the control of how much is eaten. This is likely the result of the increased number of individuals with eating disorders in the Western world. Feeding behavior is highly complex, and is controlled by many psychological, physiological, biochemical, and immunological factors. The aim of this review is to clarify the involvement of fatty acids in eating disorders such as anorexia and binge eating disorder. The review will describe the modified fatty acid profile observed in individuals with anorexia or binge eating disorder, and discuss on what factors fatty acids can exert beneficial effects. In addition, the differences and similarities between anorexia and binge eating disorder will be discussed. We suggest that beneficial effects of essential fatty acids on both anorexia and binge eating disorder can be explained by the stabilizing effect of those fatty acids on the neuronal membrane fluidity index.

  8. Molecular mechanism underlying sialic acid as an essential nutrient for brain development and cognition.

    PubMed

    Wang, Bing

    2012-05-01

    The early stages of neurodevelopment in infants are crucial for establishing neural structures and synaptic connections that influence brain biochemistry well into adulthood. This postnatal period of rapid neural growth is of critical importance for cell migration, neurite outgrowth, synaptic plasticity, and axon fasciculation. These processes thus place an unusually high demand on the intracellular pool of nutrients and biochemical precursors. Sialic acid (Sia), a family of 9-carbon sugar acids, occurs in large amounts in human milk oligosaccharides and is an essential component of brain gangliosides and sialylated glycoproteins, particularly as precursors for the synthesis of the polysialic acid (polySia) glycan that post-translationally modify the cell membrane-associated neural cell adhesion molecules (NCAM). Human milk is noteworthy in containing exceptionally high levels of Sia-glycoconjugates. The predominate form of Sia in human milk is N-acetylneuraminic acid (Neu5Ac). Infant formula, however, contains low levels of Sia consisting of both Neu5Ac and N-glycolyneuraminic acid (Neu5Gc). Current studies implicate Neu5Gc in several human inflammatory diseases. Polysialylated NCAM and neural gangliosides both play critical roles in mediating cell-to-cell interactions important for neuronal outgrowth, synaptic connectivity, and memory formation. A diet rich in Sia also increases the level of Sia in the brains of postnatal piglets, the expression level of 2 learning-related genes, and enhances learning and memory.

  9. Nutrition in brain development and aging: role of essential fatty acids.

    PubMed

    Uauy, Ricardo; Dangour, Alan D

    2006-05-01

    The essential fatty acids (EFAs), particularly the n-3 long-chain polyunsaturated fatty acids (LCPs), are important for brain development during both the fetal and postnatal period. They are also increasingly seen to be of value in limiting the cognitive decline during aging. EFA deficiency was first shown over 75 years ago, but the more subtle effects of the n-3 fatty acids in terms of skin changes, a poor response to linoleic acid supplementation, abnormal visual function, and peripheral neuropathy were only discovered later. Both n-3 and n-6 LCPs play important roles in neuronal growth, development of synaptic processing of neural cell interaction, and expression of genes regulating cell differentiation and growth. The fetus and placenta are dependent on maternal EFA supply for their growth and development, with docosahexaenomic acid (DHA)-supplemented infants showing significantly greater mental and psychomotor development scores (breast-fed children do even better). Dietary DHA is needed for the optimum functional maturation of the retina and visual cortex, with visual acuity and mental development seemingly improved by extra DHA. Aging is also associated with decreased brain levels of DHA: fish consumption is associated with decreased risk of dementia and Alzheimer's disease, and the reported daily use of fish-oil supplements has been linked to improved cognitive function scores, but confirmation of these effects is needed.

  10. Mutational Insights into the Roles of Amino Acid Residues in Ligand Binding for Two Closely Related Family 16 Carbohydrate Binding Modules

    SciTech Connect

    Su, Xiaoyun; Agarwal, Vinayak; Dodd, Dylan; Bae, Brian; Mackie, Roderick I.; Nair, Satish K.; Cann, Isaac K.O.

    2010-11-22

    Carbohydrate binding modules (CBMs) are specialized proteins that bind to polysaccharides and oligosaccharides. Caldanaerobius polysaccharolyticus Man5ACBM16-1/CBM16-2 bind to glucose-, mannose-, and glucose/mannose-configured substrates. The crystal structures of the two proteins represent the only examples in CBM family 16, and studies that evaluate the roles of amino acid residues in ligand binding in this family are lacking. In this study, we probed the roles of amino acids (selected based on CBM16-1/ligand co-crystal structures) on substrate binding. Two tryptophan (Trp-20 and Trp-125) and two glutamine (Gln-81 and Gln-93) residues are shown to be critical in ligand binding. Additionally, several polar residues that flank the critical residues also contribute to ligand binding. The CBM16-1 Q121E mutation increased affinity for all substrates tested, whereas the Q21G and N97R mutants exhibited decreased substrate affinity. We solved CBM/substrate co-crystal structures to elucidate the molecular basis of the increased substrate binding by CBM16-1 Q121E. The Gln-121, Gln-21, and Asn-97 residues can be manipulated to fine-tune ligand binding by the Man5A CBMs. Surprisingly, none of the eight residues investigated was absolutely conserved in CBM family 16. Thus, the critical residues in the Man5A CBMs are either not essential for substrate binding in the other members of this family or the two CBMs are evolutionarily distinct from the members available in the current protein database. Man5A is dependent on its CBMs for robust activity, and insights from this study should serve to enhance our understanding of the interdependence of its catalytic and substrate binding modules.

  11. Regulation of catabolism of microinjected ribonuclease A. Identification of residues 7-11 as the essential pentapeptide

    SciTech Connect

    Dice, J.F.; Chiang, H.L.; Spencer, E.P.; Backer, J.M.

    1986-05-25

    We have identified a pentapeptide region of microinjected ribonuclease A that is required for enhanced degradation of this protein during serum withdrawal. We introduced reductively methylated (/sup 3/H)ribonuclease A, (/sup 3/H)ribonuclease S-protein (residues 21-124), and (/sup 3/H)ribonuclease S-peptide (residues 1-20) into the cytosol of human fibroblasts by red cell-mediated microinjection and osmotic lysis of pinosomes. The degradative rates of ribonuclease A and ribonuclease S-peptide are increased 2-fold upon withdrawal of serum, while catabolism of ribonuclease S-protein is not regulated in this manner. Certain fragments of ribonuclease S-peptide are also degraded in a serum-dependent fashion (residues 1-14 and 4-13), while other fragments are not (residues 1-10 and 2-8). (/sup 3/H)Ribonuclease S-peptide is cleaved into two smaller radioactive peptides during loading into red cell ghosts. We tentatively identified the larger fragment as residues 7-11 based on its molecular weight determined by Sephadex chromatography in the presence of 8 M urea combined with sequential Edman degradation to identify the position of radioactive lysines. The smaller peptide fragment appears to be the amino-terminal dipeptide, Lys-Glu, and/or residues 7-8, Lys-Phe. After microinjection into fibroblasts, the pentapeptide is degraded at an enhanced rate in the absence of serum, while degradation of the dipeptide is not affected. We confirmed that residues 7-11 constitute the larger hydrolysis product of S-peptide by synthesizing this pentapeptide and radiolabeling it by reductive methylation. It migrated at the expected position after Sephadex chromatography in 8 M urea and was further hydrolyzed only slightly during loading into red cells.

  12. Essentials in the diagnosis of acid-base disorders and their high altitude application.

    PubMed

    Paulev, P E; Zubieta-Calleja, G R

    2005-09-01

    This report describes the historical development in the clinical application of chemical variables for the interpretation of acid-base disturbances. The pH concept was already introduced in 1909. Following World War II, disagreements concerning the definition of acids and bases occurred, and since then two strategies have been competing. Danish scientists in 1923 defined an acid as a substance able to give off a proton at a given pH, and a base as a substance that could bind a proton, whereas the North American Singer-Hasting school in 1948 defined acids as strong non-buffer anions and bases as non-buffer cations. As a consequence of this last definition, electrolyte disturbances were mixed up with real acid-base disorders and the variable, strong ion difference (SID), was introduced as a measure of non-respiratory acid-base disturbances. However, the SID concept is only an empirical approximation. In contrast, the Astrup/Siggaard-Andersen school of scientists, using computer strategies and the Acid-base Chart, has made diagnosis of acid-base disorders possible at a glance on the Chart, when the data are considered in context with the clinical development. Siggaard-Andersen introduced Base Excess (BE) or Standard Base Excess (SBE) in the extracellular fluid volume (ECF), extended to include the red cell volume (eECF), as a measure of metabolic acid-base disturbances and recently replaced it by the term Concentration of Titratable Hydrogen Ion (ctH). These two concepts (SBE and ctH) represent the same concentration difference, but with opposite signs. Three charts modified from the Siggaard-Andersen Acid-Base Chart are presented for use at low, medium and high altitudes of 2500 m, 3500 m, and 4000 m, respectively. In this context, the authors suggest the use of Titratable Hydrogen Ion concentration Difference (THID) in the extended extracellular fluid volume, finding it efficient and better than any other determination of the metabolic component in acid

  13. Maternal di-(2-ethylhexyl)-phthalate exposure influences essential fatty acid homeostasis in rat placenta.

    PubMed

    Xu, Y; Agrawal, S; Cook, T J; Knipp, G T

    2008-11-01

    Maintaining essential fatty acid (EFA) homeostasis during pregnancy is critical for fetal development. As the organ that controls the maternal-to-fetal supply of nutrients, the placenta plays a significant role in guiding EFA transfer to the fetus. Many EFA homeostasis proteins are regulated by peroxisome proliferator-activated receptors (PPARs). The metabolites of di-(2-ethylhexyl)-phthalate (DEHP), a ubiquitous environmental contaminant, might influence EFA homeostasis via trans-activation of PPARs with subsequent downstream effects on EFA transporters and enzymes. To investigate DEHP's effect on placental/fetal EFA homeostasis, female Sprague-Dawley rats were orally gavaged with either vehicle or DEHP at 750 or 1500 mg/kg/day from gestational day (GD) 0 to GD 19. Changes in the expression of several EFA homeostasis regulating proteins were determined in the junctional (JXN) and labyrinthine (LAB) zones of the placenta, including PPAR isoforms (alpha, beta and gamma), fatty acid translocase (FAT/CD36), fatty acid transport protein 1 (FATP1), plasma membrane fatty acid binding protein (FABPpm), heart cytoplasmic fatty acid binding protein (HFABP), cytochrome P450 (CYP) 4A1, and cyclooxygenase (COX)-1 and -2. Additionally, effects of DEHP maternal exposure on the placental transfer and fetal distribution of representative EFAs, arachidonic acid (AA) and docosahexaenoic acid (DHA), and the placental production of prostaglandins (PGs) were investigated. Expression of PPARalpha, PPARgamma, FAT/CD36, FATP1, HFABP and CYP4A1 was up-regulated in JXN and/or LAB while COX-2 was down-regulated in JXN. PPARbeta, FABPpm, and COX-1 demonstrated variable expression. Reduced directional maternal-to-fetal placental transfer and altered fetal distribution of AA and DHA were observed in concordance with a decreased total placental PG production. These results correlate with previous in vitro data, suggesting that DEHP could influence placental EFA homeostasis with potential

  14. Leaching of lead from zinc leach residue in acidic calcium chloride aqueous solution

    NASA Astrophysics Data System (ADS)

    Wang, Le; Mu, Wen-ning; Shen, Hong-tao; Liu, Shao-ming; Zhai, Yu-chun

    2015-05-01

    A process with potentially reduced environmental impacts and occupational hazards of lead-bearing zinc plant residue was studied to achieve a higher recovery of lead via a cost-effective and environmentally friendly process. This paper describes an optimization study on the leaching of lead from zinc leach residue using acidic calcium chloride aqueous solution. Six main process conditions, i.e., the solution pH value, stirring rate, concentration of CaCl2 aqueous solution, liquid-to-solid (L/S) ratio, leaching temperature, and leaching time, were investigated. The microstructure and components of the residue and tailing were characterized using scanning electron microscopy (SEM) and X-ray diffraction (XRD). On the basis of experimental results, the optimum reaction conditions were determined to be a solution pH value of 1, a stirring rate of 500 r·min-1, a CaCl2 aqueous solution concentration of 400 g·L-1, a liquid-to-solid mass ratio of 7:1, a leaching temperature of 80°C, and a leaching time of 45 min. The leaching rate of lead under these conditions reached 93.79%, with an iron dissolution rate of 19.28%. Silica did not take part in the chemical reaction during the leaching process and was accumulated in the residue.

  15. Radionuclide Leaching from Residual Solids Remaining after Acid Dissolution of Composite K East Canister Sludge

    SciTech Connect

    Delegard, C.H.; Rinehart, D.E.; Soderquist, C.Z.; Fadeff, S.K.

    1999-04-02

    Laboratory tests were performed to examine mixed nitric/hydrofluoric acid leach treatments for decontaminating dissolver residual solids (KECDVSR24H-2) produced during a 20- to 24-hr dissolution of a composite K East (KE) Basin canister sludge in 95 C 6 M nitric acid (HNO{sub 3}). The scope of this testing has been described in Section 4.5 of ''Testing Strategy to Support the Development of K Basin Sludge Treatment Process'' (Flament 1998). Radionuclides sorbed or associated with the residual solids generated in the K Basin sludge treatment process can restrict disposal of this solid to the Environmental Restoration Disposal Facility (ERDF). The starting dissolver residual solid for this testing, KECDVSR24H-2, contains radionuclides at concentrations which exceed the ERDF Waste Acceptance Criteria for TRU by about a factor of 70, for {sup 239}Pu by a factor of 200, and for {sup 241}Am by a factor of 50. The solids also exceed the ERDF criterion for {sup 137}Cs by a factor of 2 and uranium by a factor of 5. Therefore, the radionuclides of greatest interest in this leaching study are first {sup 239}Pu and {sup 241}Am (both components of TRU) and then uranium and {sup 137}Cs.

  16. Functional role of polar amino acid residues in Na+/H+ exchangers.

    PubMed Central

    Wiebe, C A; Dibattista, E R; Fliegel, L

    2001-01-01

    Na(+)/H(+) exchangers are a family of ubiquitous membrane proteins. In higher eukaryotes they regulate cytosolic pH by removing an intracellular H(+) in exchange for an extracellular Na(+). In yeast and Escherichia coli, Na(+)/H(+) exchangers function in the opposite direction to remove intracellular Na(+) in exchange for extracellular H(+). Na(+)/H(+) exchangers display an internal pH-sensitivity that varies with the different antiporter types. Only recently have investigations examined the amino acids involved in pH-sensitivity and in cation binding and transport. Histidine residues are good candidates for H(+)-sensing amino acids, since they can ionize within the physiological pH range. Histidine residues have been shown to be important in the function of the E. coli Na(+)/H(+) exchanger NhaA and in the yeast Na(+)/H(+) exchanger sod2. In E. coli, His(225) of NhaA may function to interact with, or regulate, the pH-sensory region of NhaA. In sod2, His(367) is also critical to transport and may be a functional analogue of His(225) of NhaA. Histidine residues are not critical for the function of the mammalian Na(+)/H(+) exchanger, although an unusual histidine-rich sequence of the C-terminal tail has some influence on activity. Other amino acids involved in cation binding and transport by Na(+)/H(+) exchangers are only beginning to be studied. Amino acids with polar side chains such as aspartate and glutamate have been implicated in transport activity of NhaA and sod2, but have not been studied in the mammalian Na(+)/H(+) exchanger. Further studies are needed to elucidate the mechanisms involved in pH-sensitivity and cation binding and transport by Na(+)/H(+) exchangers. PMID:11415429

  17. Prediction of functionally important residues in globular proteins from unusual central distances of amino acids

    PubMed Central

    2011-01-01

    Background Well-performing automated protein function recognition approaches usually comprise several complementary techniques. Beside constructing better consensus, their predictive power can be improved by either adding or refining independent modules that explore orthogonal features of proteins. In this work, we demonstrated how the exploration of global atomic distributions can be used to indicate functionally important residues. Results Using a set of carefully selected globular proteins, we parametrized continuous probability density functions describing preferred central distances of individual protein atoms. Relative preferred burials were estimated using mixture models of radial density functions dependent on the amino acid composition of a protein under consideration. The unexpectedness of extraordinary locations of atoms was evaluated in the information-theoretic manner and used directly for the identification of key amino acids. In the validation study, we tested capabilities of a tool built upon our approach, called SurpResi, by searching for binding sites interacting with ligands. The tool indicated multiple candidate sites achieving success rates comparable to several geometric methods. We also showed that the unexpectedness is a property of regions involved in protein-protein interactions, and thus can be used for the ranking of protein docking predictions. The computational approach implemented in this work is freely available via a Web interface at http://www.bioinformatics.org/surpresi. Conclusions Probabilistic analysis of atomic central distances in globular proteins is capable of capturing distinct orientational preferences of amino acids as resulting from different sizes, charges and hydrophobic characters of their side chains. When idealized spatial preferences can be inferred from the sole amino acid composition of a protein, residues located in hydrophobically unfavorable environments can be easily detected. Such residues turn out to be

  18. Conformational characterization of the 1-aminocyclobutane-1-carboxylic acid residue in model peptides.

    PubMed

    Gatos, M; Formaggio, F; Crisma, M; Toniolo, C; Bonora, G M; Benedetti, Z; Di Blasio, B; Iacovino, R; Santini, A; Saviano, M; Kamphuis, J

    1997-01-01

    A series of N- and C-protected, monodispersed homo-oligopeptides (to the dodecamer level) from the small-ring alicyclic C alpha, alpha-dialkylated glycine 1-aminocyclobutane-1-carboxylic acid (Ac4c) and two Ala/Ac4c tripeptides were synthesized by solution methods and fully characterized. The conformational preferences of all the model peptides were determined in deuterochloroform solution by FT-IR absorption and 1H-NMR. The molecular structures of the amino acid derivatives Z-Ac4c-OH and Z2-Ac4c-OH, the tripeptides Z-(Ac4c)3-OtBu, Z-Ac4c-(L-Ala)2-OMe and Z-L-Ala-Ac4c-L-Ala-OMe, and the tetrapeptide Z-(Ac4c)4-OtBu were determined in the crystal state by X-ray diffraction. The average geometry of the cyclobutyl moiety of the Ac4c residue was assessed and the tau(N-C alpha-C') bond angle was found to be significantly expanded from the regular tetrahedral value. The conformational data are strongly in favour of the conclusion that the Ac4c residue is an effective beta-turn and helix former. A comparison with the structural propensities of alpha-aminoisobutyric acid, the prototype of C alpha, alpha-dialkylated glycines, and the other extensively investigated members of the family of 1-aminocycloalkane-1-carboxylic acids (Acnc, with n = 3, 5-8) is made and the implications for the use of the Ac4c residue in conformationally constrained peptide analogues are briefly examined.

  19. A Novel Treatment for Acid Mine Drainage Utilizing Reclaimed Limestone Residual

    SciTech Connect

    Horace K. Moo-Young; Charles E. Ochola

    2004-08-31

    The viability of utilizing Reclaimed Limestone Residual (RLR) to remediate Acid Mine Drainage (AMD) was investigated. Physical and chemical characterization of RLR showed that it is composed of various minerals that contain significant quantities of limestone or calcium bearing compounds that can be exploited for acid neutralization. Acid Neutralization Potential (ANP) test results showed that RLR has a neutralization potential of approximately 83% as calcium carbonate (CaCO{sub 3}). Neutralization tests with most of the heavy metals associated with AMD showed removal efficiencies of over 99%. An unexpected benefit of utilizing RLR was the removal of hexavalent chromium Cr (VI) from the aqueous phase. Due to an elevation in pH by RLR most AMD heavy metals are removed from solution by precipitation as their metal hydroxides. Cr (VI) however is not removed by pH elevation and therefore subsequent ongoing tests to elucidate the mechanism responsible for this reaction were conducted.

  20. Pollen feeding in the butterfly Heliconius charitonia: isotopic evidence for essential amino acid transfer from pollen to eggs.

    PubMed

    O'Brien, Diane M; Boggs, Carol L; Fogel, Marilyn L

    2003-12-22

    Heliconius and Laparus butterflies exhibit a unique pollen-collecting behaviour that enhances lifespan and fecundity. The specific nutritional contribution of pollen, however, had not been previously demonstrated. We used stable isotope variation to trace the carbon flow into eggs from corn pollen provided experimentally to ovipositing female Heliconius charitonia, and to evaluate the use of isotopically contrasting nectar sugars in egg amino acids. The delta(13)C of individual amino acids from pollen, larval host plant and the eggs from experimental butterflies was measured with gas chromatography/combustion/isotope ratio mass spectrometry (GC/C/IRMS), to evaluate amino acid transfer. The delta(13)C of egg essential amino acids indicated a transfer of essential amino acids from pollen to butterfly eggs. However, the delta(13)C of non-essential amino acids reflected the isotopic composition of the artificial nectar, indicating that H. charitonia synthesizes non-essential amino acids from dietary sugars. This, to our knowledge, is the first direct demonstration of amino acid transfer from pollen to butterfly eggs, and suggests that essential amino acids in particular are a key resource for extending lifespan and fecundity in Heliconius butterflies.

  1. Supplemental dietary leucine and the skeletal muscle anabolic response to essential amino acids.

    PubMed

    Pasiakos, Stefan M; McClung, James P

    2011-09-01

    Skeletal muscle protein synthesis (MPS) is regulated by a number of dietary factors, to include essential amino acids (EAAs). Leucine, a branched-chain amino acid, has been identified as a stimulator of MPS in many cell culture and animal studies. However, whether supplemental leucine exerts a unique stimulatory effect, as compared to other EAAs, on muscle anabolism in humans has not been clearly demonstrated. A recent study found no improvement in resting MPS in adults who consumed a 10 g EAA supplement providing added leucine (3.5 g leucine) when compared to a control 10 g EAA supplement (1.8 g leucine). These findings suggest that added leucine is unnecessary for the stimulation of MPS when sufficient EAAs are provided; however, the study of supplemental leucine during conditions such as endurance exercise, caloric deprivation, and ageing may be warranted.

  2. Plastidic aspartate aminotransferases and the biosynthesis of essential amino acids in plants.

    PubMed

    de la Torre, Fernando; Cañas, Rafael A; Pascual, M Belén; Avila, Concepción; Cánovas, Francisco M

    2014-10-01

    In the chloroplasts and in non-green plastids of plants, aspartate is the precursor for the biosynthesis of different amino acids and derived metabolites that play distinct and important roles in plant growth, reproduction, development or defence. Aspartate biosynthesis is mediated by the enzyme aspartate aminotransferase (EC 2.6.1.1), which catalyses the reversible transamination between glutamate and oxaloacetate to generate aspartate and 2-oxoglutarate. Plastids contain two aspartate aminotransferases: a eukaryotic-type and a prokaryotic-type bifunctional enzyme displaying aspartate and prephenate aminotransferase activities. A general overview of the biochemistry, regulation, functional significance, and phylogenetic origin of both enzymes is presented. The roles of these plastidic aminotransferases in the biosynthesis of essential amino acids are discussed.

  3. Acid hydrolysis of Curcuma longa residue for ethanol and lactic acid fermentation.

    PubMed

    Nguyen, Cuong Mai; Nguyen, Thanh Ngoc; Choi, Gyung Ja; Choi, Yong Ho; Jang, Kyoung Soo; Park, Youn-Je; Kim, Jin-Cheol

    2014-01-01

    This research examines the acid hydrolysis of Curcuma longa waste, to obtain the hydrolysate containing lactic acid and ethanol fermentative sugars. A central composite design for describing regression equations of variables was used. The selected optimum condition was 4.91% sulphuric acid, 122.68°C and 50 min using the desirability function under the following conditions: the maximum reducing sugar (RS) yield is within the limited range of the 5-hydroxymethylfurfural (HMF) and furfural concentrations. Under the condition, the obtained solution contained 144 g RS/L, 0.79 g furfural/L and 2.59 g HMF/L and was directly fermented without a detoxification step. The maximum product concentration, average productivity, RS conversion and product yield were 115.36 g/L, 2.88 g/L/h, 89.43% and 64% for L-lactic acid; 113.92 g/L, 2.59 g/L/h, 88.31% and 63.29% for D-lactic acid; and 55.03 g/L, 1.38 g/L/h, 42.66 and 30.57%, respectively, for ethanol using a 7-L jar fermenter.

  4. [Nitrate nitrogen leaching and residue of humic acid fertilizer in field soil].

    PubMed

    Liu, Fang-chun; Xing, Shang-jun; Duan, Chun-hua; Du, Zhen-yu; Ma, Hai-lin; Ma, Bing-yao

    2010-07-01

    To elucidate the potential influence of humic acidfertilizer on groundwater and soil quality in clay soil (CS) and sandy soil (SS), nitrate nitrogen leaching and residue of different fertilizers in field soil were studied using a self-made leaching field device. Nitrate nitrogen concentration in leaching water of fertilizer treatments was 28.1%-222.2% higher than that of non-nitrogen treatment in different times, but humic acid fertilizer could prevent nitrate nitrogen leaching both in CS and SS, especially in CS. Nitrate nitrogen concentration of leaching water in CS was 41.2%-59.1% less than that in SS and the inhibiting effect in CS was greater than that in SS. Nitrate nitrogen could be accumulated in soil profile by fertilizer application. The residue of nitrate nitrogen retained in 0-40 cm soil layer of humic acid fertilizer treatment was 59.8% and 54.4% respectively, higher than that of urea and compound fertilizer treatments. Nitrate nitrogen amount of humic acid, urea and compound fertilizer treatments in SS was significantly less than that in CS, being 81.7%, 81.1% and 47.6% respectively. Compared with the conventional fertilizer, humic acid fertilizer treatment improved the contents of organic matter, available nitrogen, phosphorus, and potassium of upper layer soil as well as cation exchange capacity. Besides, total amount of water-soluble salts in humic acid fertilizer treatment was decreased by 24.8% and 22.5% in comparison to urea and compound fertilizer treatments in CS, respectively. In summary, the application of humic acid fertilizer could improve physical and chemical properties of upper layer soil and reduce the risk of potential pollution to groundwater.

  5. "Silent" Amino Acid Residues at Key Subunit Interfaces Regulate the Geometry of Protein Nanocages.

    PubMed

    Zhang, Shengli; Zang, Jiachen; Zhang, Xiaorong; Chen, Hai; Mikami, Bunzo; Zhao, Guanghua

    2016-11-22

    Rendering the geometry of protein-based assemblies controllable remains challenging. Protein shell-like nanocages represent particularly interesting targets for designed assembly. Here, we introduce an engineering strategy-key subunit interface redesign (KSIR)-that alters a natural subunit-subunit interface by selective deletion of a small number of "silent" amino acid residues (no participation in interfacial interactions) into one that triggers the generation of a non-native protein cage. We have applied KSIR to construct a non-native 48-mer nanocage from its native 24-mer recombinant human H-chain ferritin (rHuHF). This protein is a heteropolymer composed of equal numbers of two different subunits which are derived from one polypeptide. This strategy has allowed the study of conversion between protein nanocages with different geometries by re-engineering key subunit interfaces and the demonstration of the important role of the above-mentioned specific residues in providing geometric specificity for protein assembly.

  6. Chemical modification of amino acid residues in glycerinated Vorticella stalk and Ca(2+)-induced contractility.

    PubMed

    Kono, R; Ochiai, T; Asai, H

    1997-01-01

    The glycerinated stalk of the peritrich ciliate Vorticella, was treated with various reagents to chemically modify the amino acid residues. The influences of these modifcations on spasmoneme contractility were investigated. First, it was confirmed that the spasmoneme contraction is not inhibited by alteration of SH groups. It was also demonstrated that chemical modification of methionine and tryptophan residues abolishes spasmoneme contractility. The reagents used for chemical modification were N-bromosuccinimide (NBS), chloramine T, and 2-hydroxy-5-nitrobenzyl bromide (HNBB), which abolished spasmoneme contractility at concentrations of 40-50 microM, 200-300 microM, and 4 mM, respectively. These results suggest that, along with Ca2+ binding proteins, there are other as yet to be identified proteins involved in contractility.

  7. A conserved amino acid residue critical for product and substrate specificity in plant triterpene synthases

    PubMed Central

    Salmon, Melissa; Thimmappa, Ramesha B.; Minto, Robert E.; Melton, Rachel E.; O’Maille, Paul E.; Hemmings, Andrew M.; Osbourn, Anne

    2016-01-01

    Triterpenes are structurally complex plant natural products with numerous medicinal applications. They are synthesized through an origami-like process that involves cyclization of the linear 30 carbon precursor 2,3-oxidosqualene into different triterpene scaffolds. Here, through a forward genetic screen in planta, we identify a conserved amino acid residue that determines product specificity in triterpene synthases from diverse plant species. Mutation of this residue results in a major change in triterpene cyclization, with production of tetracyclic rather than pentacyclic products. The mutated enzymes also use the more highly oxygenated substrate dioxidosqualene in preference to 2,3-oxidosqualene when expressed in yeast. Our discoveries provide new insights into triterpene cyclization, revealing hidden functional diversity within triterpene synthases. They further open up opportunities to engineer novel oxygenated triterpene scaffolds by manipulating the precursor supply. PMID:27412861

  8. Defining membrane spanning domains and crucial membrane-localized acidic amino acid residues for K⁺ transport of a Kup/HAK/KT-type Escherichia coli potassium transporter.

    PubMed

    Sato, Yoko; Nanatani, Kei; Hamamoto, Shin; Shimizu, Makoto; Takahashi, Miho; Tabuchi-Kobayashi, Mayumi; Mizutani, Akifumi; Schroeder, Julian I; Souma, Satoshi; Uozumi, Nobuyuki

    2014-05-01

    Potassium (K(+))-uptake transport proteins present in prokaryote and eukaryote cells are categorized into two classes; Trk/Ktr/HKT, K(+) channel, and Kdp belong to the same superfamily, whereas the remaining K(+)-uptake family, Kup/HAK/KT has no homology to the others, and neither its membrane topology nor crucial residues for K(+) uptake have been identified. We examined the topology of Kup from Escherichia coli. Results from the reporter fusion and cysteine labeling assays support a model with 12 membrane-spanning domains. A model for proton-coupled K(+) uptake mediated by Kup has been proposed. However, this study did not show any stimulation of Kup activity at low pH and any evidence of involvement of the three His in Kup-mediated K(+) uptake. Moreover, replacement of all four cysteines of Kup with serine did not abolish K(+) transport activity. To gain insight on crucial residues of Kup-mediated K(+) uptake activity, we focused on acidic residues in the predicted external and transmembrane regions, and identified four residues in the membrane regions required for K(+) uptake activity. This is different from no membrane-localized acidic residues essential for Trk/Ktr/HKTs, K(+) channels and Kdp. Taken together, these results demonstrate that Kup belongs to a distinct type of K(+) transport system.

  9. Volatile fatty acids distribution during acidogenesis of algal residues with pH control.

    PubMed

    Li, Yan; Hua, Dongliang; Zhang, Jie; Zhao, Yuxiao; Xu, Haipeng; Liang, Xiaohui; Zhang, Xiaodong

    2013-06-01

    The anaerobic acidification of protein-rich algal residues with pH control (4, 6, 8, 10) was studied in batch reactors, which was operated at mesophilic(35 °C) condition. The distribution of major volatile fatty acids (VFAs) during acidogenesis was emphasized in this paper. The results showed that the acidification efficiency and VFAs distribution in the acid reactor strongly depended on the pH. The main product for all the runs involved acetic acid except that the proportion of butyric acid acidified at pH 6 was relatively higher. The other organic acids remained at lower levels. The VFAs yield reached the maximum value with about 0.6 g VFAs/g volatile solid (VS) added as pH was 8, and also the content of total ammonia nitrogen (TAN) reached the highest values of 9,629 mg/l. Low acidification degrees were obtained under the conditions at pH 4 and 10, which was not suitable for the metabolism of acidogens. Hydralic retention time (HRT) required for different conditions varied. As a consequence, it was indicated that pH was crucial to the acidification efficiency and products distribution. The investigation of acidogenesis process, which was producing the major substrates, short-chain fatty acids, would play the primary role in the efficient operation of methanogenesis.

  10. Emerging Perspectives on Essential Amino Acid Metabolism in Obesity and the Insulin-Resistant State12

    PubMed Central

    Adams, Sean H.

    2011-01-01

    Dysregulation of insulin action is most often considered in the context of impaired glucose homeostasis, with the defining feature of diabetes mellitus being elevated blood glucose concentration. Complications arising from the hyperglycemia accompanying frank diabetes are well known and epidemiological studies point to higher risk toward development of metabolic disease in persons with impaired glucose tolerance. Although the central role of proper blood sugar control in maintaining metabolic health is well established, recent developments have begun to shed light on associations between compromised insulin action [obesity, prediabetes, and type 2 diabetes mellitus (T2DM)] and altered intermediary metabolism of fats and amino acids. For amino acids, changes in blood concentrations of select essential amino acids and their derivatives, in particular BCAA, sulfur amino acids, tyrosine, and phenylalanine, are apparent with obesity and insulin resistance, often before the onset of clinically diagnosed T2DM. This review provides an overview of these changes and places recent observations from metabolomics research into the context of historical reports in the areas of biochemistry and nutritional biology. Based on this synthesis, a model is proposed that links the FFA-rich environment of obesity/insulin resistance and T2DM with diminution of BCAA catabolic enzyme activity, changes in methionine oxidation and cysteine/cystine generation, and tissue redox balance (NADH/NAD+). PMID:22332087

  11. Amino Acid Residues in the Putative Transmembrane Domain 11 of Human Organic Anion Transporting Polypeptide 1B1 Dictate Transporter Substrate Binding, Stability, and Trafficking.

    PubMed

    Hong, Weifang; Wu, Zhixuan; Fang, Zihui; Huang, Jiujiu; Huang, Hong; Hong, Mei

    2015-12-07

    Organic anion transporting polypeptides (OATPs, gene symbol SLCO) are membrane proteins that mediate the sodium-independent transport of a wide range of endogenous and exogenous compounds. Due to their broad substrate specificity, wide tissue distribution, and involvement in drug-drug interactions, OATPs have been considered as key players in drug absorption, distribution, and excretion. Transmembrane domains (TMs) are crucial structural features involved in proper functions of many transporters. According to computer-based modeling and previous studies of our laboratory and others, TM11 of OATP1B1 may face the substrate interaction pocket and thus play an important role in the transport function of the protein. Alanine-scanning of the transmembrane domain identified seven critical amino acid residues within the region. Further analysis revealed that alanine substitution of these residues resulted in reduced protein stability, which led to significantly decreased protein expression on the plasma membrane. In addition, all mutants exhibited an altered Km for ES uptake (either high affinity or low affinity component, or both), though Km for taurocholate transport only changed in R580A, G584A, and F591A. These results suggested that critical residues in TM11 not only affect protein stability of the transporter, but its interaction with substrates as well. The identification of seven essential residues out of 21 TM amino acids highlighted the importance of this transmembrane domain in the proper function of OATP1B1.

  12. A residue in the TRPM2 channel outer pore is crucial in determining species-dependent sensitivity to extracellular acidic pH.

    PubMed

    Zou, Jie; Yang, Wei; Beech, David J; Jiang, Lin-Hua

    2011-08-01

    Acidic pH is an important parameter regulating ion channel activity and its biological function. This study investigated inhibition of the hTRPM2 channels by extracellular acidic pH and compared the sensitivity of human (h) and mouse (m) TRPM2 channel to such an inhibition. The initial inhibition of hTRPM2 channel currents was substantially reversible, but the reversibility progressively diminished as the exposure to acidic pH was prolonged and it was essentially lost in the steady state, suggesting that extracellular acidic pH induces initial reversible inhibition and subsequent irreversible inactivation. Like the hTRPM2 channel, the mTRPM2 channel was sensitive to inhibition by pH 4.0-5.5, but the kinetics was significantly slower. Moreover, in contrast to the complete inhibition of the hTRPM2 channel, the mTRPM2 channel was insensitive to pH 6.0. Replacement of residue Gln(992) in the outer pore with the equivalent residue His(995) in the hTRPM2 channel resulted in a mutant mTRPM2 channel with the pH sensitivity and kinetics of inhibition of the wild-type hTRPM2 channel. Conversely, the reciprocal mutation H995Q in the hTRPM2 channel dramatically slowed down the kinetics of inhibition. Swapping other residues in the pore region failed to produce such opposing effects. Taken together, our results suggest a crucial role of residue His(995)/Gln(992) in the outer pore of TRPM2 channels in determining species-dependent effects of extracellular acidic pH.

  13. Effects of Cilnidipine on Heart Rate and Uric Acid Metabolism in Patients With Essential Hypertension

    PubMed Central

    Das, Arijit; Kumar, Prakash; Kumari, Abha; Chandra, Satish; Gari, Manju; Singh, Nidhi; Dey, Debleena

    2016-01-01

    Background The relation between hypertension and hyperuricemia has been established by epidemiological studies. Calcium channel blockers are one of the first-line drugs for newly diagnosed patients with essential hypertension. Cilnidipine is a new calcium channel blocker acting by blocking both L- and N-type calcium channels. The aim of this study was to compare the effectiveness of amlodipine and cilnidipine in patients with essential hypertension and their effects on heart rate and serum uric acid levels. Methods Out of 100 enrolled patients, 92 completed the study. They were randomly assigned to amlodipine (N = 47) and cilnidipine (N = 45) groups. Cilnidipine was started at 10 mg/day and then adjusted to 5 - 20 mg/day, and amlodipine was started at 5 mg/day and then adjusted to 2.5 - 10 mg/day. Results After 24 weeks of study, patients in cilnidipine groups showed significant reduction in heart rate and serum uric acid levels from baseline (P = 0.00). Conclusion In clinical setting where both hypertension and hyperuricemia exist, cilnidipine can be a promising drug of choice. PMID:28197287

  14. [Role of essential fatty acids in trophometabolic interactions in the freshwater ecosystems (a review)].

    PubMed

    Sushchik, N N

    2008-01-01

    Polyunsaturated fatty acids (PUFA) of omega3 family are of crucial physiological importance for the most animals and they are an essential and deficient component of human nutrition. These compounds are most effectively synthesized by some groups of algae, hence, aquatic ecosystems are considered to be the main source of these PUFA for human nutrition. Factors controlling the content and distribution of omega3 PUFA in freshwater organisms of basic trophic levels and determined PUFA final production in freshwater ecosystems are considered in the review. PUFA biosynthesis is known to be tightly related to basic fatty acid metabolic pathways. Hence, fatty composition and the PUFA content of major freshwater hydrobiont groups, including bacteria, algae, invertebrates and vertebrates, and environmental and population age effects are described. The peculiarities of PUFA transfer between organisms of various trophic levels are discussed. The essential omega3 PUFA is one of the important parameter of food quality of aquatic consumers and they can determine the rate of energy and matter transfer between producers and primary consumers and, as a result, in a whole freshwater food chain. Analysis of PUFA content and its regulation in biomass of various fish populations indicates that freshwater ecosystems are of the same value in respect of PUFA sources as marine ecosystems. Despite the great practical importance, the studies focused on production and whole pools of omega3 PUFA in different freshwater ecosystems are still scarce and need to be continued.

  15. Three Tyrosine Residues in the Erythropoietin Receptor Are Essential for Janus Kinase 2 V617F Mutant-induced Tumorigenesis.

    PubMed

    Ueda, Fumihito; Tago, Kenji; Tamura, Hiroomi; Funakoshi-Tago, Megumi

    2017-02-03

    The erythropoietin receptor (EpoR) regulates development of blood cells, and its full activation normally requires the cytokine erythropoietin (Epo). In the case of myeloproliferative neoplasms (MPN), Epo-independent signaling through EpoR can be caused by a point mutation, V617F, in the EpoR-interacting tyrosine kinase Janus kinase 2 (JAK2). In cells expressing the JAK2 V617F mutant, eight tyrosine residues in the intracellular domain of EpoR are phosphorylated, but the functional role of these phosphorylations in oncogenic signaling is incompletely understood. Here, to evaluate the functional consequences of the phosphorylation of these tyrosine residues, we constructed an EpoR-8YF mutant in which we substituted all eight tyrosine residues with phenylalanine. Co-expression of EpoR-8YF with the JAK2 V617F mutant failed to induce cytokine-independent cell proliferation and tumorigenesis, indicating that JAK2-mediated EpoR phosphorylation is the reason for JAK2 V617F mutant-induced oncogenic signaling. An exhaustive mutational analysis of the eight EpoR tyrosine residues indicated that three of these residues, Tyr-343, Tyr-460, and Tyr-464, are required for the JAK2 V617F mutant to exhibit its oncogenic activity. We also showed that phosphorylation at these three residues was necessary for full activation of the transcription factor STAT5, which is a critical downstream factor of JAK2 V617F-induced oncogenic signaling. In contrast, Epo stimulation could moderately stimulate the proliferation of cells expressing wild type JAK2 and EpoR-8YF, suggesting that the requirement of the phosphorylation of these three tyrosine residues seems to be specific for the oncogenic proliferation provoked by V617F mutation. Collectively, these results have revealed that phosphorylation of Tyr-343, Tyr-460, and Tyr-464 in EpoR underlies JAK2 V617F mutant-induced tumorigenesis. We propose that the targeted disruption of this pathway has therapeutic utility for managing MPN.

  16. Influence of glutamic acid residues and pH on the properties of transmembrane helices.

    PubMed

    Rajagopalan, Venkatesan; Greathouse, Denise V; Koeppe, Roger E

    2017-03-01

    Negatively charged side chains are important for the function of particular ion channels and certain other membrane proteins. To investigate the influence of single glutamic acid side chains on helices that span lipid-bilayer membranes, we have employed GWALP23 (acetyl-GGALW(5)LALALALALALALW(19)LAGA-amide) as a favorable host peptide framework. We substituted individual Leu residues with Glu residues (L12E or L14E or L16E) and incorporated specific (2)H-labeled alanine residues within the core helical region or near the ends of the sequence. Solid-state (2)H NMR spectra reveal little change for the core labels in GWALP23-E12, -E14 and -E16 over a pH range of 4 to 12.5, with the spectra being broader for samples in DOPC compared to DLPC bilayers. The spectra for samples with deuterium labels near the helix ends on alanines 3 and 21 show modest pH-dependent changes in the extent of unwinding of the helix terminals in DLPC and DOPC bilayers. The combined results indicate minor overall responses of these transmembrane helices to changes in pH, with the most buried residue E12 showing no pH dependence. While the Glu residues E14 and E16 may have high pKa values in the lipid bilayer environment, it is also possible that a paucity of helix response is masking the pKa values. Interestingly, when E16 is present, spectral changes at high pH report significant local unwinding of the core helix. Our results are consistent with the expectation that buried carboxyl groups aggressively hold their protons and/or waters of hydration.

  17. Changes in transepidermal water loss and the composition of epidermal lecithin after applications of pure fatty acid triglycerides to skin of essential fatty acid-deficient rats.

    PubMed

    Hartop, P J; Prottey, C

    1976-09-01

    The importance of various unsaturated fatty acid triglycerides to the repair of faulty skin barrier function was studied in essential fatty acid-deficient rats. Following cutaneous application of the pure triglycerides for up to 5 days, the hitherto high rate of transepidermal water loss, characteristic of essential fatty acid deficiency in rats, was reduced by the triglycerides of linoleic and gamma-linolenic acids. Incorporation of the applied fatty acids into the lecithin of the epidermis accompanied these changes in water loss, indicating that cutaneously applied triglycerides may be metabolized by the skin and incorporated into complex lipids. Other fatty acid triglycerides, including alpha-linolenic, dihomo-gamma-linolenic, arachidonic and omega-7-heneicosatrienoic acid, did not lower the rate of transepidermal water loss, although all were incorporated into epidermal structural lipids. The non-essential oleic acid also had no effect upon the rate of transepidermal water loss. These data suggest that of the two main essential fatty acids that occur in skin, linoleic acid and arachidonic acid, the former specifically plays an important role in regulating barrier function whereas the later may have a separate function, such as serving as a precursor of prostaglandins.

  18. Hydroxycarboxylic acid receptors are essential for breast cancer cells to control their lipid/fatty acid metabolism.

    PubMed

    Stäubert, Claudia; Broom, Oliver Jay; Nordström, Anders

    2015-08-14

    Cancer cells exhibit characteristic changes in their metabolism with efforts being made to address them therapeutically. However, targeting metabolic enzymes as such is a major challenge due to their essentiality for normal proliferating cells. The most successful pharmaceutical targets are G protein-coupled receptors (GPCRs), with more than 40% of all currently available drugs acting through them.We show that, a family of metabolite-sensing GPCRs, the Hydroxycarboxylic acid receptor family (HCAs), is crucial for breast cancer cells to control their metabolism and proliferation.We found HCA1 and HCA3 mRNA expression were significantly increased in breast cancer patient samples and detectable in primary human breast cancer patient cells. Furthermore, siRNA mediated knock-down of HCA3 induced considerable breast cancer cell death as did knock-down of HCA1, although to a lesser extent. Liquid Chromatography Mass Spectrometry based analyses of breast cancer cell medium revealed a role for HCA3 in controlling intracellular lipid/fatty acid metabolism. The presence of etomoxir or perhexiline, both inhibitors of fatty acid β-oxidation rescues breast cancer cells with knocked-down HCA3 from cell death.Our data encourages the development of drugs acting on cancer-specific metabolite-sensing GPCRs as novel anti-proliferative agents for cancer therapy.

  19. Type II Fatty Acid Synthesis Is Essential for the Replication of Chlamydia trachomatis*

    PubMed Central

    Yao, Jiangwei; Abdelrahman, Yasser M.; Robertson, Rosanna M.; Cox, John V.; Belland, Robert J.; White, Stephen W.; Rock, Charles O.

    2014-01-01

    The major phospholipid classes of the obligate intracellular bacterial parasite Chlamydia trachomatis are the same as its eukaryotic host except that they also contain chlamydia-made branched-chain fatty acids in the 2-position. Genomic analysis predicts that C. trachomatis is capable of type II fatty acid synthesis (FASII). AFN-1252 was deployed as a chemical tool to specifically inhibit the enoyl-acyl carrier protein reductase (FabI) of C. trachomatis to determine whether chlamydial FASII is essential for replication within the host. The C. trachomatis FabI (CtFabI) is a homotetramer and exhibited typical FabI kinetics, and its expression complemented an Escherichia coli fabI(Ts) strain. AFN-1252 inhibited CtFabI by binding to the FabI·NADH complex with an IC50 of 0.9 μm at saturating substrate concentration. The x-ray crystal structure of the CtFabI·NADH·AFN-1252 ternary complex revealed the specific interactions between the drug, protein, and cofactor within the substrate binding site. AFN-1252 treatment of C. trachomatis-infected HeLa cells at any point in the infectious cycle caused a decrease in infectious titers that correlated with a decrease in branched-chain fatty acid biosynthesis. AFN-1252 treatment at the time of infection prevented the first cell division of C. trachomatis, although the cell morphology suggested differentiation into a metabolically active reticulate body. These results demonstrate that FASII activity is essential for C. trachomatis proliferation within its eukaryotic host and validate CtFabI as a therapeutic target against C. trachomatis. PMID:24958721

  20. Type II fatty acid synthesis is essential for the replication of Chlamydia trachomatis.

    PubMed

    Yao, Jiangwei; Abdelrahman, Yasser M; Robertson, Rosanna M; Cox, John V; Belland, Robert J; White, Stephen W; Rock, Charles O

    2014-08-08

    The major phospholipid classes of the obligate intracellular bacterial parasite Chlamydia trachomatis are the same as its eukaryotic host except that they also contain chlamydia-made branched-chain fatty acids in the 2-position. Genomic analysis predicts that C. trachomatis is capable of type II fatty acid synthesis (FASII). AFN-1252 was deployed as a chemical tool to specifically inhibit the enoyl-acyl carrier protein reductase (FabI) of C. trachomatis to determine whether chlamydial FASII is essential for replication within the host. The C. trachomatis FabI (CtFabI) is a homotetramer and exhibited typical FabI kinetics, and its expression complemented an Escherichia coli fabI(Ts) strain. AFN-1252 inhibited CtFabI by binding to the FabI·NADH complex with an IC50 of 0.9 μM at saturating substrate concentration. The x-ray crystal structure of the CtFabI·NADH·AFN-1252 ternary complex revealed the specific interactions between the drug, protein, and cofactor within the substrate binding site. AFN-1252 treatment of C. trachomatis-infected HeLa cells at any point in the infectious cycle caused a decrease in infectious titers that correlated with a decrease in branched-chain fatty acid biosynthesis. AFN-1252 treatment at the time of infection prevented the first cell division of C. trachomatis, although the cell morphology suggested differentiation into a metabolically active reticulate body. These results demonstrate that FASII activity is essential for C. trachomatis proliferation within its eukaryotic host and validate CtFabI as a therapeutic target against C. trachomatis.

  1. Conformation of dehydropentapeptides containing four achiral amino acid residues – controlling the role of L-valine

    PubMed Central

    Krzciuk-Gula, Joanna; Makowski, Maciej; Latajka, Rafał; Kafarski, Paweł

    2014-01-01

    Summary Structural studies of pentapeptides containing an achiral block, built from two dehydroamino acid residues (ΔZPhe and ΔAla) and two glycines, as well as one chiral L-Val residue were performed using NMR spectroscopy. The key role of the L-Val residue in the generation of the secondary structure of peptides is discussed. The obtained results suggest that the strongest influence on the conformation of peptides arises from a valine residue inserted at the C-terminal position. The most ordered conformation was found for peptide Boc-Gly-ΔAla-Gly-ΔZPhe-Val-OMe (3), which adopts a right-handed helical conformation. PMID:24778717

  2. Stable isotope studies reveal pathways for the incorporation of non-essential amino acids in Acyrthosiphon pisum (pea aphids).

    PubMed

    Haribal, Meena; Jander, Georg

    2015-12-01

    Plant roots incorporate inorganic nitrogen into the amino acids glutamine, glutamic acid, asparagine and aspartic acid, which together serve as the primary metabolites of nitrogen transport to other tissues. Given the preponderance of these four amino acids, phloem sap is a nutritionally unbalanced diet for phloem-feeding insects. Therefore, aphids and other phloem feeders typically rely on microbial symbionts for the synthesis of essential amino acids. To investigate the metabolism of the four main transport amino acids by the pea aphid (Acyrthosiphon pisum), and its Buchnera aphidicola endosymbionts, aphids were fed defined diets with stable isotope-labeled glutamine, glutamic acid, asparagine or aspartic acid (U-(13)C, U-(15)N; U-(15)N; α-(15)N; or γ-(15)N). The metabolic fate of the dietary (15)N and (13)C was traced using gas chromatography-mass spectrometry (GC-MS). Nitrogen was the major contributor to the observed amino acid isotopomers with one additional unit mass (M+1). However, there was differential incorporation, with the amine nitrogen of asparagine being incorporated into other amino acids more efficiently than the amide nitrogen. Higher isotopomers (M+2, M+3 and M+4) indicated the incorporation of varying numbers of (13)C atoms into essential amino acids. GC-MS assays also showed that, even with an excess of dietary labeled glutamine, glutamic acid, asparagine or aspartic acid, the overall content of these amino acids in aphid bodies was mostly the product of catabolism of dietary amino acids and subsequent re-synthesis within the aphids. Thus, these predominant dietary amino acids are not passed directly to Buchnera endosymbionts for synthesis of essential amino acids, but are rather are produced de novo, most likely by endogenous aphid enzymes.

  3. Biochemical evaluation of borage (Borago officinalis) rosette leaves through their essential oil and fatty acid composition.

    PubMed

    Mhamdi, Baya; Aidi Wannes, Wissem; Marzouk, Brahim

    2007-06-01

    Borago officinalis rosette leaves were sampled in the region of Amdoun (Tunisia) during different stages of their development. Essential oil contents varied from 0.01% to 0.13% respectively in young and adult leaves. Twenty three volatile compounds were identified. Hydrocarbons, mainly represented by nonadecane (29.8%), tetracosane (11.3%) and heptacosane (4.7%), constituted the major class in the young leaves (45.8%), followed by aldehydes (22.4%). The percentages of these two classes decreased to reach respectively 15% and 8.1% in adult leaves in favour of alcohols (57.9%) where cis-3-hexenol (29.6%) and hexanol (14.5%) were the main compounds. Total fatty acids amounts increased from 5.03 mg/g DW in young leaves to 32.23 mg/g DW in adult ones. The predominant fatty acids were alpha-linolenic (C18:3 n-3), stearidonic (C18:4 n-3), gamma-linolenic (C18:3 n-6), palmitic (C16: 0) and linoleic (C18:2 n-6) acids.

  4. Inhibition of nocturnal acidity is important but not essential for duodenal ulcer healing.

    PubMed Central

    Bianchi Porro, G; Parente, F; Sangaletti, O

    1990-01-01

    We have determined the relative importance of day and night time gastric acid inhibition for duodenal ulcer healing by comparing the anti-ulcer efficacy of a single morning with that of a single bedtime dose of ranitidine. One hundred and thirty patients with active duodenal ulcer were randomly assigned to a double-blind therapy with ranitidine 300 mg at 8 am or the same dose at 10 pm for up to eight weeks. The antisecretory effects of these regimens were also assessed by 24 h intragastric pH monitoring in 18 of these patients. At four weeks ulcers had healed in 41/61 (67%) of patients taking the morning dose and in 47/63 (75%) of those receiving the nocturnal dose (95% CI for the difference -0.09 +0.25; p ns). At eight weeks, the corresponding healing rates were 82% and 85.5%, respectively (95% CI for the difference -0.11 +0.17; p ns). Both treatments were significantly superior to placebo in raising 24 h intragastric pH, although the effects of the morning dose were of shorter duration than those of the nocturnal dose. These findings suggest that suppression of nocturnal acidity is important but not essential to promote healing of duodenal ulcers; a prolonged period of acid inhibition during the day (as obtained with a single large morning dose of H2-blockers) may be equally effective. PMID:2186980

  5. Histidine-41 of the cytochrome b5 domain of the borage delta6 fatty acid desaturase is essential for enzyme activity.

    PubMed

    Sayanova, O; Shewry, P R; Napier, J A

    1999-10-01

    Unlike most other plant microsomal desaturases, the Delta6-fatty acid desaturase from borage (Borago officinalis) contains an N-terminal extension that shows homology to the small hemoprotein cytochrome (Cyt) b5. To determine if this domain serves as a functional electron donor for the Delta6-fatty acid desaturase, mutagenesis and functional analysis by expression in transgenic Arabidopsis was carried out. Although expression of the wild-type borage Delta6-fatty acid desaturase resulted in the synthesis and accumulation of Delta6-unsaturated fatty acids, this was not observed in plants transformed with N-terminally deleted forms of the desaturase. Site-directed mutagenesis was used to disrupt one of the axial heme-binding residues (histidine-41) of the Cyt b5 domain; expression of this mutant form of the Delta6-desaturase in transgenic plants failed to produce Delta6-unsaturated fatty acids. These data indicate that the Cyt b5 domain of the borage Delta6-fatty acid desaturase is essential for enzymatic activity.

  6. Optimization of thermal-dilute sulfuric acid pretreatment for enhancement of methane production from cassava residues.

    PubMed

    Zhang, Qinghua; Tang, Lei; Zhang, Jianhua; Mao, Zhonggui; Jiang, Li

    2011-02-01

    In this study, the pretreatment of cassava residues by thermal-dilute sulfuric acid (TDSA) hydrolysis was investigated by means of a statistically designed set of experiments. A three-factor central composite design (CCD) was employed to identify the optimum pretreatment condition of cassava residues for methane production. The individual and interactive effects of temperature, H(2)SO(4) concentration and reaction time on increase of methane yield (IMY) were evaluated by applying response surface methodology (RSM). After optimization, the resulting optimum pretreatment condition was 157.84°C, utilizing 2.99% (w/w TS) H(2)SO(4) for 20.15 min, where the maximum methane yield (248 mL/g VS) was 56.96% higher than the control (158 mL/g VS), which was very close to the predict value 56.53%. These results indicate the model obtained through RSM analysis is suit to predict the optimum pretreatment condition and there is great potential of using TDSA pretreatment of cassava residues to enhance methane yield.

  7. Differentiating amino acid residues and side chain orientations in peptides using scanning tunneling microscopy.

    PubMed

    Claridge, Shelley A; Thomas, John C; Silverman, Miles A; Schwartz, Jeffrey J; Yang, Yanlian; Wang, Chen; Weiss, Paul S

    2013-12-11

    Single-molecule measurements of complex biological structures such as proteins are an attractive route for determining structures of the large number of important biomolecules that have proved refractory to analysis through standard techniques such as X-ray crystallography and nuclear magnetic resonance. We use a custom-built low-current scanning tunneling microscope to image peptide structures at the single-molecule scale in a model peptide that forms β sheets, a structural motif common in protein misfolding diseases. We successfully differentiate between histidine and alanine amino acid residues, and further differentiate side chain orientations in individual histidine residues, by correlating features in scanning tunneling microscope images with those in energy-optimized models. Beta sheets containing histidine residues are used as a model system due to the role histidine plays in transition metal binding associated with amyloid oligomerization in Alzheimer's and other diseases. Such measurements are a first step toward analyzing peptide and protein structures at the single-molecule level.

  8. Identification of Structural and Catalytic Classes of Highly Conserved Amino Acid Residues in Lysine 2,3-Aminomutase †

    PubMed Central

    Chen, Dawei; Frey, Perry A.; Lepore, Bryan W.; Ringe, Dagmar; Ruzicka, Frank J.

    2008-01-01

    Lysine 2,3-aminomutase (LAM) from Clostridium subterminale SB4 catalyzes the interconversion of (S)-lysine and (S)-β-lysine by a radical mechanism involving coenzymatic actions of S-adenosylmethionine (SAM), a [4Fe-4S] cluster, and pyridoxal-5′-phosphate (PLP). The enzyme contains a number of conserved acidic residues and a cysteine and arginine-rich motif, that binds iron and sulfide in the [4Fe–4S] cluster. The results of activity and iron, sulfide, and PLP analysis of variants resulting from site-specific mutations of the conserved acidic residues and the arginine residues in the iron-sulfide binding motif indicate two classes of conserved residues of each type. Mutation of the conserved residues Arg134, Asp293, and Asp330 abolish all enzymatic activity. Based on the x-ray crystal structure, these residues bind the ε-aminium and α-carboxylate groups of (S)-lysine. However, among these residues only Asp293 appears to be important for stabilizing the [4Fe–4S] cluster. Members of a second group of conserved residues appear to stabilize the structure of LAM. Mutations of arginine residues 130, 135, and 136 and acidic residues Glu86, Asp165, Glu236, and Asp172 dramatically decrease iron and sulfide contents in the purified variants. Mutation of Asp96 significantly decreases iron and sulfide content. Variants in Arg130 or Asp172 display no detectable activity, whereas variants in the other positions display low to very low activities. Structural roles are assigned to this latter class of conserved amino acids. In particular, a network of hydrogen bonded interactions of Arg130, Glu86, Arg135 and the main chain carbonyl groups of Cys132 and Leu55 appears to stabilize the [4Fe–4S] cluster. PMID:17042481

  9. Identification of Key Amino Acid Residues Modulating Intracellular and In vitro Microcin E492 Amyloid Formation.

    PubMed

    Aguilera, Paulina; Marcoleta, Andrés; Lobos-Ruiz, Pablo; Arranz, Rocío; Valpuesta, José M; Monasterio, Octavio; Lagos, Rosalba

    2016-01-01

    Microcin E492 (MccE492) is a pore-forming bacteriocin produced and exported by Klebsiella pneumoniae RYC492. Besides its antibacterial activity, excreted MccE492 can form amyloid fibrils in vivo as well as in vitro. It has been proposed that bacterial amyloids can be functional playing a biological role, and in the particular case of MccE492 it would control the antibacterial activity. MccE492 amyloid fibril's morphology and formation kinetics in vitro have been well-characterized, however, it is not known which amino acid residues determine its amyloidogenic propensity, nor if it forms intracellular amyloid inclusions as has been reported for other bacterial amyloids. In this work we found the conditions in which MccE492 forms intracellular amyloids in Escherichia coli cells, that were visualized as round-shaped inclusion bodies recognized by two amyloidophilic probes, 2-4'-methylaminophenyl benzothiazole and thioflavin-S. We used this property to perform a flow cytometry-based assay to evaluate the aggregation propensity of MccE492 mutants, that were designed using an in silico prediction of putative aggregation hotspots. We established that the predicted amino acid residues 54-63, effectively act as a pro-amyloidogenic stretch. As in the case of other amyloidogenic proteins, this region presented two gatekeeper residues (P57 and P59), which disfavor both intracellular and in vitro MccE492 amyloid formation, preventing an uncontrolled aggregation. Mutants in each of these gatekeeper residues showed faster in vitro aggregation and bactericidal inactivation kinetics, and the two mutants were accumulated as dense amyloid inclusions in more than 80% of E. coli cells expressing these variants. In contrast, the MccE492 mutant lacking residues 54-63 showed a significantly lower intracellular aggregation propensity and slower in vitro polymerization kinetics. Electron microscopy analysis of the amyloids formed in vitro by these mutants revealed that, although with

  10. Identification of Key Amino Acid Residues Modulating Intracellular and In vitro Microcin E492 Amyloid Formation

    PubMed Central

    Aguilera, Paulina; Marcoleta, Andrés; Lobos-Ruiz, Pablo; Arranz, Rocío; Valpuesta, José M.; Monasterio, Octavio; Lagos, Rosalba

    2016-01-01

    Microcin E492 (MccE492) is a pore-forming bacteriocin produced and exported by Klebsiella pneumoniae RYC492. Besides its antibacterial activity, excreted MccE492 can form amyloid fibrils in vivo as well as in vitro. It has been proposed that bacterial amyloids can be functional playing a biological role, and in the particular case of MccE492 it would control the antibacterial activity. MccE492 amyloid fibril’s morphology and formation kinetics in vitro have been well-characterized, however, it is not known which amino acid residues determine its amyloidogenic propensity, nor if it forms intracellular amyloid inclusions as has been reported for other bacterial amyloids. In this work we found the conditions in which MccE492 forms intracellular amyloids in Escherichia coli cells, that were visualized as round-shaped inclusion bodies recognized by two amyloidophilic probes, 2-4′-methylaminophenyl benzothiazole and thioflavin-S. We used this property to perform a flow cytometry-based assay to evaluate the aggregation propensity of MccE492 mutants, that were designed using an in silico prediction of putative aggregation hotspots. We established that the predicted amino acid residues 54–63, effectively act as a pro-amyloidogenic stretch. As in the case of other amyloidogenic proteins, this region presented two gatekeeper residues (P57 and P59), which disfavor both intracellular and in vitro MccE492 amyloid formation, preventing an uncontrolled aggregation. Mutants in each of these gatekeeper residues showed faster in vitro aggregation and bactericidal inactivation kinetics, and the two mutants were accumulated as dense amyloid inclusions in more than 80% of E. coli cells expressing these variants. In contrast, the MccE492 mutant lacking residues 54–63 showed a significantly lower intracellular aggregation propensity and slower in vitro polymerization kinetics. Electron microscopy analysis of the amyloids formed in vitro by these mutants revealed that, although

  11. Effects of the number of fatty acid residues on the phase behaviors of decaglycerol fatty acid esters.

    PubMed

    Ai, Sakiko; Ishitobi, Masahiko

    2006-04-15

    The effects of the number of fatty acid residues (n) in decaglycerol fatty acid esters, i.e., decaglycerol laurates (abbreviated to (C11)nG10), on the phase behaviors of three laurate esters, (C11)1.9G10, (C11)2.7G10, and (C11)3.4G10, were investigated. The unreacted decaglycerol remaining in each ester was removed by liquid extraction before use. (C11)1.9G10 formed hexagonal liquid crystals in aqueous solutions, while (C11)2.7G10 and (C11)3.4G10, which are more hydrophobic than (C11)1.9G10, formed lamellar liquid crystals. The cloud point in aqueous solution was measured for mixtures of these three esters. The cloud phenomenon was observed when the weight ratio of hydrophilic groups to the total surfactant (WH/WS) was around 0.6. The cloud point shifted to a markedly higher temperature, even with a slight increase in the WH/WS ratio. The solubilization abilities of (C11)nG10 for the oils m-xylene and (R)-(+)-limonene were also examined. When the WH/WS ratio was between 0.60 and 0.64, (C11)nG10 formed microemulsions and lyotropic liquid crystals in the presence of water and the oils. These self-organized structures were stable, even above 90 degrees C. It is concluded that the phase behavior of (C11)nG10 are insensitive to temperature, but strongly dependent on both the WH/WS ratio and the number of fatty acid residues (n).

  12. Differences in sialic acid residues among bone alkaline phosphatase isoforms: a physical, biochemical, and immunological characterization.

    PubMed

    Magnusson, P; Farley, J R

    2002-12-01

    High-performance liquid chromatography (HPLC) separates three human bone alkaline phosphatase (BALP) isoforms in serum; two major BALP isoforms, B1 and B2, and a minor fraction, B/I, which is composed on average of 70% bone and 30% intestinal ALP. The current studies were intended to identify an in vitro source of the BALP isoforms for physical, biochemical, and immunological characterizations. The three BALP isoforms were identified in extracts of human osteosarcoma (SaOS-2) cells, by HPLC, after separation by anion-exchange chromatography. All three BALP isoforms were similar with respect to freeze-thaw stability, solubility, heat inactivation, and inhibition by L-phenylalanine, L-homoarginine, and levamisole. The isoforms were also kinetically similar (i.e., maximal velocity and KM at pH 8.8 and pH 10.0). The isoforms differed, however, with respect to sensitivity to precipitation with wheat germ agglutinin (WGA), P < 0.001, but not Concanavalin A. At 3.0 mg/ml, WGA precipitated approximately 25% of B/I but more than 80% of B1 and B2. Molecular weights were estimated by native gradient gel electrophoresis: B/I, 126 kDa; B1, 136 kDa; and B2, 141 kDa. Desialylation with neuraminidase reduced the apparent sizes of B1 and B2 to 127 kDa (i.e., approximately to that of B/I). The total carbohydrate content was calculated to be 18 kDa, 28 kDa, and 33 kDa (i.e., 14%, 21%, and 23%) for the BALP isofonns, B/I, B1, and B2, respectively. The number of sialic acid residues was estimated to be 29 and 45, for each B1 and B2 homodimer, respectively. Apparent discrepancies between these estimates of molecular weight and estimates based on gel filtration chromatography were attributed to nonspecific interactions between carbohydrate residues and the gel filtration beads. All three BALP isoforms showed similar dose-dependent linearity in the commercial Alkphase-B and Tandem-MP Ostase immunoassays, r = 0.944 and r = 0.985, respectively (P < 0.001). In summary, our data indicate that

  13. Role of enthalpy-entropy compensation interactions in determining the conformational propensities of amino acid residues in unfolded peptides.

    PubMed

    Toal, Siobhan E; Verbaro, Daniel J; Schweitzer-Stenner, Reinhard

    2014-02-06

    The driving forces governing the unique and restricted conformational preferences of amino acid residues in the unfolded state are still not well understood. In this study, we experimentally determine the individual thermodynamic components underlying intrinsic conformational propensities of these residues. Thermodynamic analysis of ultraviolet-circular dichroism (UV-CD) and (1)H NMR data for a series of glycine capped amino acid residues (i.e., G-x-G peptides) reveals the existence of a nearly exact enthalpy-entropy compensation for the polyproline II-β strand equilibrium for all investigated residues. The respective ΔHβ, ΔSβ values exhibit a nearly perfect linear relationship with an apparent compensation temperature of 295 ± 2 K. Moreover, we identified iso-equilibrium points for two subsets of residues at 297 and 305 K. Thus, our data suggest that within this temperature regime, which is only slightly below physiological temperatures, the conformational ensembles of amino acid residues in the unfolded state differ solely with respect to their capability to adopt turn-like conformations. Such iso-equilibria are rarely observed, and their existence herein indicates a common physical origin behind conformational preferences, which we are able to assign to side-chain dependent backbone solvation. Conformational effects such as differences between the number of sterically allowed side chain rotamers can contribute to enthalpy and entropy but not to the Gibbs energy associated with conformational preferences. Interestingly, we found that alanine, aspartic acid, and threonine are the only residues which do not share these iso-equilbiria. The enthalpy-entropy compensation discovered as well as the iso-equilbrium and thermodynamics obtained for each amino acid residue provide a new and informative way of identifying the determinants of amino acid propensities in unfolded and disordered states.

  14. Quantitative solid state NMR analysis of residues from acid hydrolysis of loblolly pine wood.

    PubMed

    Sievers, Carsten; Marzialetti, Teresita; Hoskins, Travis J C; Valenzuela Olarte, Mariefel B; Agrawal, Pradeep K; Jones, Christopher W

    2009-10-01

    The composition of solid residues from hydrolysis reactions of loblolly pine wood with dilute mineral acids is analyzed by (13)C Cross Polarization Magic Angle Spinning (CP MAS) NMR spectroscopy. Using this method, the carbohydrate and lignin fractions are quantified in less than 3h as compared to over a day using wet chemical methods. In addition to the quantitative information, (13)C CP MAS NMR spectroscopy provides information on the formation of additional extractives and pseudo lignin from the carbohydrates. Being a non-destructive technique, NMR spectroscopy provides unambiguous evidence of the presence of side reactions and products, which is a clear advantage over the wet chemical analytical methods. Quantitative results from NMR spectroscopy and proximate analysis are compared for the residues from hydrolysis of loblolly pine wood under 13 different conditions; samples were treated either at 150 degrees C or 200 degrees C in the presence of various acids (HCl, H(2)SO(4), H(3)PO(4), HNO(3) and TFA) or water. The lignin content determined by both methods differed on averaged by 2.9 wt% resulting in a standard deviation of 3.5 wt%. It is shown that solid degradation products are formed from saccharide precursors under harsh reaction conditions. These degradation reactions limit the total possible yield of monosaccharides from any subsequent reaction.

  15. Theoretical exploration of the cooperative effect in NMF-NMF-amino acid residue hydrogen bonding system.

    PubMed

    Li, Xichen; Liu, Wenlan; Sun, Kening; Wang, Yan; Tan, Hongwei; Chen, Guangju

    2008-09-28

    This paper presents a theoretical study of the cooperative effect in sixteen linearly-arranged trimer systems consisting of N-methylformamide dimer and an extra amino acid residue. These trimer systems, NMF-NMF-AAR, in short, have been systematically investigated by full optimization at B3LYP/cc-pVTZ level and subsequent electronic energy calculations at PBE1PBE/cc-pVTZ, HF/cc-pVTZ and MP2/cc-pVTZ, respectively. Obvious spatial transformation due to energetic factors has been found in almost all the trimers. Systematic analysis in weak interaction energy components has shown that: (1) in these trimer systems, the bonding structure and the cooperative effect combine to determine the stability of both HB1 and HB2. For HB2, the structure of the constituent amino acid residue also plays a crucial role by interfering with the neighboring moieties; (2) the large contribution of the cooperative effect to the overall hydrogen bonding energy has claimed the importance of cooperativity in our systems; (3) the non-hydrogen bonding weak interaction components are found to be non-negligible in these trimer systems; (4) moreover, the cooperative effect between these non-hydrogen bonding components is always found to be positive. The good performances of PBE1PBE and PM6 have been established by comparisons between these methods.

  16. Accurate determination of residual acrylic acid in superabsorbent polymer of hygiene products by headspace gas chromatography.

    PubMed

    Zhang, Shu-Xin; Chai, Xin-Sheng; Jiang, Ran

    2017-02-17

    This work reports on a method for the determination of residual acrylic acid (AA) in the superabsorbent polymers for hygiene products by headspace analysis. It was based on water extraction for the polymer sample at a room temperature for 50min. Then, the AA in the extractant reacted with bicarbonate solution in a closed headspace sample vial, from which the carbon dioxide generated from the reaction (within 20min at 70°C) was detected by gas chromatography (GC). It was found that there is adsorption partition equilibrium of AA between solid-liquid phases. Therefore, an equation for calculating the total AA content in the original polymers sample was derived based on the above phase equilibrium. The results show that the HS-GC method has good precision (RSD<2.51%) and good accuracy (recoveries from 93 to 105%); the limit of quantification (LOQ) was 373mg/kg. The present method is rapid, accurate, and suitable for determining total residual acrylic acid in a wide variety of applications from processing of superabsorbent polymer to commercial products quality control.

  17. Glycolic acid-catalyzed deamidation of asparagine residues in degrading PLGA matrices: a computational study.

    PubMed

    Manabe, Noriyoshi; Kirikoshi, Ryota; Takahashi, Ohgi

    2015-03-31

    Poly(lactic-co-glycolic acid) (PLGA) is a strong candidate for being a drug carrier in drug delivery systems because of its biocompatibility and biodegradability. However, in degrading PLGA matrices, the encapsulated peptide and protein drugs can undergo various degradation reactions, including deamidation at asparagine (Asn) residues to give a succinimide species, which may affect their potency and/or safety. Here, we show computationally that glycolic acid (GA) in its undissociated form, which can exist in high concentration in degrading PLGA matrices, can catalyze the succinimide formation from Asn residues by acting as a proton-transfer mediator. A two-step mechanism was studied by quantum-chemical calculations using Ace-Asn-Nme (Ace = acetyl, Nme = NHCH3) as a model compound. The first step is cyclization (intramolecular addition) to form a tetrahedral intermediate, and the second step is elimination of ammonia from the intermediate. Both steps involve an extensive bond reorganization mediated by a GA molecule, and the first step was predicted to be rate-determining. The present findings are expected to be useful in the design of more effective and safe PLGA devices.

  18. The Dual NOD1/NOD2 Agonism of Muropeptides Containing a Meso-Diaminopimelic Acid Residue

    PubMed Central

    Dagil, Yulia A.; Arbatsky, Nikolai P.; Alkhazova, Biana I.; L’vov, Vyacheslav L.; Mazurov, Dmitriy V.; Pashenkov, Mikhail V.

    2016-01-01

    Muropeptides are fragments of peptidoglycan that trigger innate immune responses by activating nucleotide-binding oligomerization domain (NOD) 1 and NOD2. Muropeptides from Gram-negative bacteria contain a meso-diaminopimelic acid (meso-DAP) residue in either a terminal or a non-terminal position. While the former ones are known to be recognized by NOD1, much less is known about recognition of muropeptides with non-terminal meso-DAP, which are most abundant moieties of Gram-negative peptidoglycans. Here, we developed a novel system to assess biological activity of muropeptides, based on CRISPR/Cas9-mediated knockout (KO) of NOD1 and NOD2 genes in modified HEK293T cells. Using NOD1/NOD2 knockout and overexpression systems, as well as human monocytes and macrophages, we refine the current view of muropeptide recognition. We show that NOD2 can recognize different natural muropeptides containing a meso-DAP residue (preferably in a non-terminal position), provided they are present at micromolar concentrations. NOD2 accepts muropeptides with long and branched peptide chains and requires an intact N-acetylmuramyl residue. Muropeptides with non-terminal meso-DAP can activate NOD1 as well, but, in this case, probably require peptidase pre-processing to expose the meso-DAP residue. Depending on NOD1/NOD2 ratio in specific cell types, meso-DAP-containing muropeptides can be recognized either primarily via NOD2 (in monocytes) or via NOD1 (in monocyte-derived macrophages and HEK293T-derived cells). The dual NOD1/NOD2 agonism of meso-DAP-containing muropeptides should be taken into account when assessing cellular responses to muropeptides and designing muropeptide immunostimulants and vaccine adjuvants. PMID:27513337

  19. Inhibition of the ATPase from Halobacterium Saccharovorum by Thiol Inhibitors: Evidence for the Presence of More Than One Essential Cysteinyl Residue

    NASA Technical Reports Server (NTRS)

    Hochstein, Lawrence I.; Emrich, Errol; Stan-Lotter, Helga; DeVincenzi, Donald L. (Technical Monitor)

    1995-01-01

    The vacuolar-like ATPase from Halobacterium saccha vorum is inhibited by N-ethylmaleimide and p-chloromercudphenylsulfonate. The failure of adenine nucleotides to protect against p-chloromercuriphenyisulfonate inhibition, of p-chloromercuriphenylsulfonate to protect against N-ethylmaleimide inhibition, and the difference in the temperature dependence of inactivation infers that the enzyme contains at least two thiols that are essential for enzyme activity. CNBr cleavage of C-14-N-ethylmaleimide labeled subunit results in two radioactive peptides that locates the N-ethylmaleimide-reactive cysteinyl residue as cysteine-262 in the H. salinarium sequence.

  20. Increasing dietary crude protein does not increase the essential amino acid requirements of kittens.

    PubMed

    Strieker, M J; Morris, J G; Rogers, Q R

    2006-08-01

    Essential amino acid (EAA) requirements of omnivores and herbivores (e.g. chicks, lambs, pigs and rats) are directly related to the concentration of dietary crude protein (CP). When an EAA is limiting in the diet, addition of a mixture of EAA lacking the limiting one (which increases dietary CP) results in a decrease in food intake and weight gain. This interaction has been referred to as an AA imbalance and has not been studied in depth in strict carnivores. The objectives of these experiments were to examine the effects on growing kittens (2-week periods) of the addition to diets of a mixture of AA lacking the limiting one. The control diets were at the requirement of the respective limiting EAA (or about 85% of the 1986 National Research Council requirement). In experiment 1, with the dietary EAAs at the minimally determined requirements, the concentration of the essential or dispensable amino acids was increased to determine if CP or an EAA was limiting. Results of growth rates (n = 12) and plasma AA concentrations indicated that tryptophan was limiting, but increased body weight gain also occurred when the concentration of CP was increased as dispensable amino acids without additional tryptophan. Experiment 1 was repeated in experiment 2 using a crossover design. Again, when tryptophan was limiting additional concentrations of dispensable AAs increased body weight gain. This response is the opposite of that in herbivores and omnivores. Experiment 3 consisted of 10 separate crossover trials, one for each of the 10 EAA and examined the effect of two concentrations of dietary CP (200 and 300 g CP/kg diet) on body weight gain of kittens (n = 8) offered diets limiting in each respective EAA. Body weight gain was numerically greater when diets contained 300 g CP/kg than 200 g CP/kg for eight of 10 EAAs (p < 0.05 for only isoleucine and threonine) when each amino acid was limiting. This response is the reverse of that which occurs in chicks, lambs, pigs and rats when

  1. [The use of essential fatty acids in the treatments of wounds].

    PubMed

    Manhezi, Andreza Cano; Bachion, Maria Márcia; Pereira, Angela Lima

    2008-01-01

    In spite of being widely spread throughout Brazil, the use of essential fatty acids (EFA) for wound healing is controversial. This study aimed at identifying and analyzing the available scientific evidence for EFA to be used in the treatment of wounds. This is a descriptive study, carried out through a systematic literature review, concerning the Biblioteca Virtual de Saúde (Health Online Library) and PubMed data bank, from 1970 to 2006. Initially, we identified 503 references. After the relevance tests I and II, 11 articles were included in the analysis, showing evidence of recommendation- level II and III for EFA to be used in burns, mediastinitis, among others situations. Most studies still refer to its use in animal. Relevant publications are still scarce.

  2. Comparison of the effects of ozone on the modification of amino acid residues in glutamine synthetase and bovine serum albumin.

    PubMed

    Berlett, B S; Levine, R L; Stadtman, E R

    1996-02-23

    During exposure to ozone, the methionine and aromatic amino acid residues of Escherichia coli glutamine synthetase (GS) and bovine serum albumin (BSA) are oxidized rapidly in the order Met > Trp > Tyr approximately His > Phe. The loss of His is matched by a nearly equivalent formation of aspartate or of a derivative that is converted to aspartic acid upon acid hydrolysis. Conversion of His to aspartate was confirmed by showing that the oxidation of E. coli protein in which all His residues were uniformly labeled with 14C gave rise to 14C-labeled aspartic acid in 80% yield and also by the demonstration that His residues in the tripeptides Ala-His-Ala or Ala-Ala-His gave rise to nearly stoichiometric amounts of aspartic acid whereas oxidation of His-Ala-Ala yielded only 36% aspartate. The oxidation of BSA and GS led to formation, respectively, of 11 and 3.3 eq of carbonyl groups and 0.5 and 0.3 eq of quinoprotein per subunit. Although BSA and GS contain nearly identical amounts of each kind of aromatic amino acid residues, oxidation of these residues in BSA was about 1.5-2.0 times faster than in GS indicating that the susceptibility to oxidation is dependent on the primary, secondary, tertiary, and quaternary structure of the protein.

  3. Kinetics of sulfuric acid leaching of cadmium from Cd-Ni zinc plant residues.

    PubMed

    Safarzadeh, Mohammad Sadegh; Moradkhani, Davood; Ojaghi-Ilkhchi, Mehdi

    2009-04-30

    Cd-Ni filtercakes are produced continuously at the third purification step in the electrolytic production of zinc in the National Iranian Lead and Zinc Company (NILZ) in northwestern Iran. In this research, the dissolution kinetics of cadmium from Cd-Ni residues produced in NILZ plant has been investigated. Hence, the effects of temperature, sulfuric acid concentration, particle size and stirring speed on the kinetics of cadmium dissolution in sulfuric acid were studied. The dissolution kinetics at 25-55 degrees C and tacid concentration, solid/liquid ratio and particle size were also achieved. The rate of reaction at first 5 min based on diffusion-controlled process can be expressed by a semi-empirical equation as:It was determined that the dissolution rate increased with increasing sulfuric acid concentration and decreasing particle size.

  4. Identification of acid-base catalytic residues of high-Mr thioredoxin reductase from Plasmodium falciparum.

    PubMed

    McMillan, Paul J; Arscott, L David; Ballou, David P; Becker, Katja; Williams, Charles H; Müller, Sylke

    2006-11-03

    High-M(r) thioredoxin reductase from the malaria parasite Plasmodium falciparum (PfTrxR) contains three redox active centers (FAD, Cys-88/Cys-93, and Cys-535/Cys-540) that are in redox communication. The catalytic mechanism of PfTrxR, which involves dithiol-disulfide interchanges requiring acid-base catalysis, was studied by steady-state kinetics, spectral analyses of anaerobic static titrations, and rapid kinetics analysis of wild-type enzyme and variants involving the His-509-Glu-514 dyad as the presumed acid-base catalyst. The dyad is conserved in all members of the enzyme family. Substitution of His-509 with glutamine and Glu-514 with alanine led to TrxR with only 0.5 and 7% of wild type activity, respectively, thus demonstrating the crucial roles of these residues for enzymatic activity. The H509Q variant had rate constants in both the reductive and oxidative half-reactions that were dramatically less than those of wild-type enzyme, and no thiolateflavin charge-transfer complex was observed. Glu-514 was shown to be involved in dithiol-disulfide interchange between the Cys-88/Cys-93 and Cys-535/Cys-540 pairs. In addition, Glu-514 appears to greatly enhance the role of His-509 in acid-base catalysis. It can be concluded that the His-509-Glu-514 dyad, in analogy to those in related oxidoreductases, acts as the acid-base catalyst in PfTrxR.

  5. Acid-catalyzed hydrothermal severity on the fractionation of agricultural residues for xylose-rich hydrolyzates.

    PubMed

    Lee, Ji Ye; Ryu, Hyun Jin; Oh, Kyeong Keun

    2013-03-01

    The objective of this work was to investigate the feasibility of acid-catalyzed hydrothermal fractionation for maximum solubilization of the hemicellulosic portion of three agricultural residues. The fractionation conditions converted into combined severity factor (CS) in the range of 1.2-2.9. The highest hemicellulose yield of 87.88% was achieved when barley straw was fractionated at a CS of 2.19. However, the maximum glucose release of 15.29% was achieved for the case of rice straw. The maximum productions of various by-products were observed with the fractionation of rape straw: 0.88 g/L of 5-hydroxymethylfurfural (5-HMF), 2.16 g/L of furfural, 0.44 g/L of levulinic acid, 1.59 g/L of formic acid, and 3.06 g/L of acetic acid. The highest selectivities, a criterion for evaluating the fractionation of 21.55 for fractionated solid and 7.48 for liquid hydrolyzate were obtained from barley straw.

  6. Bioaccumulation patterns of methyl mercury and essential fatty acids in lacustrine planktonic food webs and fish.

    PubMed

    Kainz, Martin; Telmer, Kevin; Mazumder, Asit

    2006-09-01

    Organisms of the planktonic food web convey essential nutrients as well as contaminants to animals at higher trophic levels. We measured concentrations of methyl mercury (MeHg) and essential fatty acids (EFAs, key nutrients for aquatic food webs) in four size categories of planktonic organisms - seston (10-64 microm), micro-(100-200 microm), meso-(200-500 microm), and macrozooplankton (>500 microm) - as well as total mercury (THg) and EFAs in rainbow trout (Oncorhynchus mykiss) in coastal lakes. We demonstrate that, in all lakes during this summer sampling, MeHg concentrations of planktonic organisms increase significantly with plankton size, independent of their taxonomic composition, and that their MeHg accumulation patterns predict significantly THg concentrations in rainbow trout (R2=0.71, p<0.05). However, concentrations of total EFAs do not follow this pattern. Total EFAs increased from seston to mesozooplankton but decreased in the largest zooplankton size fraction. Moreover, concentrations of individual EFA compounds in rainbow trout are consistently lower, with the exception of docosahexaenoic acid, than those in macrozooplankton. The continuous increase of MeHg concentrations in aquatic organisms, therefore, differs from patterns of EFA accumulation in zooplankton and fish. We interpret these contrasting accumulation patterns of MeHg and EFA compounds as the inability of aquatic organisms to regulate the assimilation of dietary MeHg, whereas the rate of EFA retention may be controlled to optimize their physiological performance. Therefore, we conclude that bioaccumulation patterns of Hg in these aquatic food webs are not controlled by lipid solubility and/or the retention of EFA compounds.

  7. Symbiotic essential amino acids provisioning in the American cockroach, Periplaneta americana (Linnaeus) under various dietary conditions

    PubMed Central

    Larsen, Thomas; Sabree, Zakee

    2016-01-01

    Insect gut microbes have been shown to provide nutrients such as essential amino acids (EAAs) to their hosts. How this symbiotic nutrient provisioning tracks with the host’s demand is not well understood. In this study, we investigated microbial essential amino acid (EAA) provisioning in omnivorous American cockroaches (Periplaneta americana), fed low-quality (LQD) and comparatively higher-quality dog food (DF) diets using carbon stable isotope ratios of EAAs (δ13CEAA). We assessed non-dietary EAA input, quantified as isotopic offsets (Δ13C) between cockroach (δ13CCockroach EAA) and dietary (δ13CDietary EAA) EAAs, and subsequently determined biosynthetic origins of non-dietary EAAs in cockroaches using 13C-fingerprinting with dietary and representative bacterial and fungal δ13CEAA. Investigation of biosynthetic origins of de novo non-dietary EAAs indicated bacterial origins of EAA in cockroach appendage samples, and a mixture of fungal and bacterial EAA origins in gut filtrate samples for both LQD and DF-fed groups. We attribute the bacteria-derived EAAs in cockroach appendages to provisioning by the fat body residing obligate endosymbiont, Blattabacterium and gut-residing bacteria. The mixed signatures of gut filtrate samples are attributed to the presence of unassimilated dietary, as well as gut microbial (bacterial and fungal) EAAs. This study highlights the potential impacts of dietary quality on symbiotic EAA provisioning and the need for further studies investigating the interplay between host EAA demands, host dietary quality and symbiotic EAA provisioning in response to dietary sufficiency or deficiency. PMID:27231663

  8. Symbiotic essential amino acids provisioning in the American cockroach, Periplaneta americana (Linnaeus) under various dietary conditions.

    PubMed

    Ayayee, Paul A; Larsen, Thomas; Sabree, Zakee

    2016-01-01

    Insect gut microbes have been shown to provide nutrients such as essential amino acids (EAAs) to their hosts. How this symbiotic nutrient provisioning tracks with the host's demand is not well understood. In this study, we investigated microbial essential amino acid (EAA) provisioning in omnivorous American cockroaches (Periplaneta americana), fed low-quality (LQD) and comparatively higher-quality dog food (DF) diets using carbon stable isotope ratios of EAAs (δ (13)CEAA). We assessed non-dietary EAA input, quantified as isotopic offsets (Δ(13)C) between cockroach (δ (13)CCockroach EAA) and dietary (δ (13)CDietary EAA) EAAs, and subsequently determined biosynthetic origins of non-dietary EAAs in cockroaches using (13)C-fingerprinting with dietary and representative bacterial and fungal δ (13)CEAA. Investigation of biosynthetic origins of de novo non-dietary EAAs indicated bacterial origins of EAA in cockroach appendage samples, and a mixture of fungal and bacterial EAA origins in gut filtrate samples for both LQD and DF-fed groups. We attribute the bacteria-derived EAAs in cockroach appendages to provisioning by the fat body residing obligate endosymbiont, Blattabacterium and gut-residing bacteria. The mixed signatures of gut filtrate samples are attributed to the presence of unassimilated dietary, as well as gut microbial (bacterial and fungal) EAAs. This study highlights the potential impacts of dietary quality on symbiotic EAA provisioning and the need for further studies investigating the interplay between host EAA demands, host dietary quality and symbiotic EAA provisioning in response to dietary sufficiency or deficiency.

  9. Bicarbonate-sensing soluble adenylyl cyclase is an essential sensor for acid/base homeostasis

    PubMed Central

    Tresguerres, Martin; Parks, Scott K.; Salazar, Eric; Levin, Lonny R.; Goss, Greg G.; Buck, Jochen

    2009-01-01

    pH homeostasis is essential for life, yet it remains unclear how animals sense their systemic acid/base (A/B) status. Soluble adenylyl cyclase (sAC) is an evolutionary conserved signaling enzyme that produces the second messenger cAMP in response to bicarbonate ions (HCO3−). We cloned the sAC ortholog from the dogfish, a shark that regulates blood A/B by absorbing and secreting protons (H+) and HCO3− at its gills. Similar to mammalian sAC, dogfish soluble adenylyl cyclase (dfsAC) is activated by HCO3− and can be inhibited by two structurally and mechanistically distinct small molecule inhibitors. dfsAC is expressed in the gill epithelium, where the subset of base-secreting cells resides. Injection of inhibitors into animals under alkaline stress confirmed that dfsAC is essential for maintaining systemic pH and HCO3− levels in the whole organism. One of the downstream effects of dfsAC is to promote the insertion of vacuolar proton pumps into the basolateral membrane to absorb H+ into the blood. sAC orthologs are present throughout metazoans, and mammalian sAC is expressed in A/B regulatory organs, suggesting that systemic A/B sensing via sAC is widespread in the animal kingdom. PMID:20018667

  10. Bicarbonate-sensing soluble adenylyl cyclase is an essential sensor for acid/base homeostasis.

    PubMed

    Tresguerres, Martin; Parks, Scott K; Salazar, Eric; Levin, Lonny R; Goss, Greg G; Buck, Jochen

    2010-01-05

    pH homeostasis is essential for life, yet it remains unclear how animals sense their systemic acid/base (A/B) status. Soluble adenylyl cyclase (sAC) is an evolutionary conserved signaling enzyme that produces the second messenger cAMP in response to bicarbonate ions (HCO(3)(-)). We cloned the sAC ortholog from the dogfish, a shark that regulates blood A/B by absorbing and secreting protons (H(+)) and HCO(3)(-) at its gills. Similar to mammalian sAC, dogfish soluble adenylyl cyclase (dfsAC) is activated by HCO(3)(-) and can be inhibited by two structurally and mechanistically distinct small molecule inhibitors. dfsAC is expressed in the gill epithelium, where the subset of base-secreting cells resides. Injection of inhibitors into animals under alkaline stress confirmed that dfsAC is essential for maintaining systemic pH and HCO(3)(-) levels in the whole organism. One of the downstream effects of dfsAC is to promote the insertion of vacuolar proton pumps into the basolateral membrane to absorb H(+) into the blood. sAC orthologs are present throughout metazoans, and mammalian sAC is expressed in A/B regulatory organs, suggesting that systemic A/B sensing via sAC is widespread in the animal kingdom.

  11. Interaction between carbohydrate residues of alpha1-acid glycoprotein (orosomucoid) and saturating concentrations of Calcofluor White. A fluorescence study.

    PubMed

    Albani, J R; Sillen, A; Plancke, Y D; Coddeville, B; Engelborghs, Y

    2000-07-24

    Calcofluor White is a fluorescent probe that interacts with polysaccharides and is commonly used in clinical studies. Interaction between Calcofluor White and carbohydrate residues of alpha1-acid glycoprotein (orosomucoid) was previously followed by fluorescence titration of the Trp residues of the protein. A stoichiometry of one Calcofluor for one protein has been found [J.R. Albani and Y.D. Plancke, Carbohydr. Res., 318 (1999) 193-200]. Alpha1-acid glycoprotein contains 40% carbohydrate by weight and has up to 16 sialic acid residues. Since binding of Calcofluor to alpha1-acid glycoprotein occurs mainly on the carbohydrate residues, we studied in the present work the interaction between Calcofluor and the protein by following the fluorescence change of the fluorophore. In order to establish the role of the sialic acid residues in the interaction, the experiments were performed with the sialylated and asialylated protein. Interaction of Calcofluor with sialylated alpha1-acid glycoprotein induces a red shift of the emission maximum of the fluorophore from 438 to 450 nm at saturation (one Calcofluor for one sialic acid) and an increase in the fluorescence intensity. At saturation the fluorescence intensity increase levels off. Binding of Calcofluor to asialylated acid glycoprotein does not change the position of the emission maximum of the fluorophore and induces a decrease in its fluorescence intensity. Saturation occurs when 10 molecules of Calcofluor are bound to 1 mol of alpha1-acid glycoprotein. Since the protein contains five heteropolysaccharide groups, we have 2 mol of Calcofluor for each group. Addition of free sialic acid to Calcofluor induces a continuous decrease in the fluorescence intensity of the fluorophore but does not change the position of the emission maximum. Our results confirm the presence of a defined spatial conformation of the sialic acid residues, a conformation that disappears when they are free in solution. Dynamics studies on Calcofluor

  12. Osmium isotope anomalies in chondrites: Results for acid residues and related leachates

    NASA Astrophysics Data System (ADS)

    Yokoyama, Tetsuya; O'D. Alexander, Conel M.; Walker, Richard J.

    2010-03-01

    We have investigated Os isotope anomalies in acid residues enriched in insoluble organic matter (IOM) extracted from ten primitive chondrites, acid leachates and residues of these fractions, as well as acid leachates of bulk chondrites. Osmium isotopic compositions of bulk carbonaceous, ordinary and enstatite chondrites are also reported. Consistent with prior results, bulk chondrites have homogeneous Os isotope compositions for s-, r-, and p-process nuclides that are indistinguishable from terrestrial, at the current level of resolution. In contrast, nearly all the IOM-rich residues are enriched in s-process Os, evidently due to the preferential incorporation of s-process enriched presolar grains (most likely presolar SiC). Presolar silicate grains that formed in red giant branch (RGB) or asymptotic giant branch (AGB) stars are also likely hosts of additional s-process Os in chondrites. Consistent with one prior study, Os released by weak acid leaching of bulk chondrites is slightly to strongly enriched in r-process nuclides, of which the carrier may be fine-grained presolar silicates formed in supernovae or unidentified solar phases. Collectively, the different, chemically concentrated components in these meteorites are variably enriched in s-, r-, and possibly p-process Os, of which the individual carriers must have been produced in multiple stellar environments. The lack of evidence for Os isotopic heterogeneity among bulk chondrites contrasts with evidence for isotopic heterogeneities for various other elements at approximately the same levels of resolution (e.g., Cr, Mo, Ru, Ba, Sm, and Nd). One possible explanation for this is that the heterogeneities for some elements in bulk materials reflect selective removal of some types of presolar grains as a result of nebular processes, and that because of the strong chemical differences between Os and the other elements, the Os was not significantly affected. Another possible explanation is that late-stage injection

  13. Phenolic acid contents, essential oil compositions and antioxidant activities of two varieties of Salvia euphratica from Turkey.

    PubMed

    Yumrutas, Onder; Sokmen, Atalay; Akpulat, H Askın; Ozturk, Nilgun; Daferera, Dimitra; Sokmen, Munevver; Tepe, Bektas

    2012-01-01

    This study was designed to evaluate the in vitro antioxidant activities of n-hexane (Hex), dichloromethane (DCM), methanol (MeOH) and essential oils (EO) extracts obtained from Salvia euphratica var. euphratica and Salvia euphratica var. leiocalycina and to determine their essential oil and phenolic acid compositions. The samples were screened for their antioxidant activity by using DPPH and β-carotene/linoleic acid assays. Methanol extracts of both varieties exhibited strong antioxidant activities. Our results showed that rosmarinic acid was dominant phenolic acid of MeOH extracts (39.4 and 55.8 µg mg⁻¹, respectively). The chemical compositions of essential oils of two varieties were analysed and their main components were determined as eucalyptol (18.4%) and trans-pinocarvyl acetate (24.9%), respectively. It can be said that these varieties could be used as natural antioxidant.

  14. Frequencies of amino acid strings in globular protein sequences indicate suppression of blocks of consecutive hydrophobic residues

    PubMed Central

    Schwartz, Russell; Istrail, Sorin; King, Jonathan

    2001-01-01

    Patterns of hydrophobic and hydrophilic residues play a major role in protein folding and function. Long, predominantly hydrophobic strings of 20–22 amino acids each are associated with transmembrane helices and have been used to identify such sequences. Much less attention has been paid to hydrophobic sequences within globular proteins. In prior work on computer simulations of the competition between on-pathway folding and off-pathway aggregate formation, we found that long sequences of consecutive hydrophobic residues promoted aggregation within the model, even controlling for overall hydrophobic content. We report here on an analysis of the frequencies of different lengths of contiguous blocks of hydrophobic residues in a database of amino acid sequences of proteins of known structure. Sequences of three or more consecutive hydrophobic residues are found to be significantly less common in actual globular proteins than would be predicted if residues were selected independently. The result may reflect selection against long blocks of hydrophobic residues within globular proteins relative to what would be expected if residue hydrophobicities were independent of those of nearby residues in the sequence. PMID:11316883

  15. Biofortification of rice with the essential amino acid lysine: molecular characterization, nutritional evaluation, and field performance

    PubMed Central

    Yang, Qing-qing; Zhang, Chang-quan; Chan, Man-ling; Zhao, Dong-sheng; Chen, Jin-zhu; Wang, Qing; Li, Qian-feng; Yu, Heng-xiu; Gu, Ming-hong; Sun, Samuel Sai-ming; Liu, Qiao-quan

    2016-01-01

    Rice (Oryza sativa L.), a major staple crop worldwide, has limited levels of the essential amino acid lysine. We previously produced engineered rice with increased lysine content by expressing bacterial aspartate kinase and dihydrodipicolinate synthase and inhibiting rice lysine ketoglutarate reductase/saccharopine dehydrogenase activity. However, the grain quality, field performance, and integration patterns of the transgenes in these lysine-enriched lines remain unclear. In the present study, we selected several elite transgenic lines with endosperm-specific or constitutive regulation of the above key enzymes but lacking the selectable marker gene. All target transgenes were integrated into the intragenic region in the rice genome. Two pyramid transgenic lines (High Free Lysine; HFL1 and HFL2) with free lysine levels in seeds up to 25-fold that of wild type were obtained via a combination of the above two transgenic events. We observed a dramatic increase in total free amino acids and a slight increase in total protein content in both pyramid lines. Moreover, the general physicochemical properties were improved in pyramid transgenic rice, but the starch composition was not affected. Field trials indicated that the growth of HFL transgenic rice was normal, except for a slight difference in plant height and grain colour. Taken together, these findings will be useful for the potential commercialization of high-lysine transgenic rice. PMID:27252467

  16. Renal effects of essential fatty acid deficiency in hydropenic and volume-expanded rats.

    PubMed

    Paixão, Ana D O; Nunes, Flávia A; Léger, Claude; Aléssio, Maria L M

    2002-01-01

    The aim of this paper was to study the effects of essential fatty acid (EFA) on fractional sodium excretion (FE(Na(+))) and renal hemodynamics in rats during hydropenia (H) and acute volume expansion (VE), successively. Mean arterial pressure (MAP) and renal blood flow (RBF) were measured using a blood pressure transducer and a flow probe, respectively, both connected to a flowmeter. Glomerular filtration rate (GFR) was estimated by inulin clearance. The rats receiving coconut oil as only source of dietary lipids (the EFA-deficient group) presented lower levels of linoleic acid in cortex and medulla and lower body weight than the rats receiving soy oil in place of coconut oil (the control non-EFA-deficient group). During H, the EFA-deficient rats exhibited a lower level of renal vascular resistance resulting in a higher level of RBF and a higher urinary flow (V') and FE(Na(+)), although GFR was lower than in the control group. During VE, the rats of the control group responded with increased MAP, RBF, V' and FE(Na(+)), which were not found in the EFA-deficient group, suggesting an impaired hemodynamic adjustment in EFA deficiency. In conclusion, both experimental conditions revealed that EFA deficiency affects the renal hemodynamics.

  17. Biofortification of rice with the essential amino acid lysine: molecular characterization, nutritional evaluation, and field performance.

    PubMed

    Yang, Qing-Qing; Zhang, Chang-Quan; Chan, Man-Ling; Zhao, Dong-Sheng; Chen, Jin-Zhu; Wang, Qing; Li, Qian-Feng; Yu, Heng-Xiu; Gu, Ming-Hong; Sun, Samuel Sai-Ming; Liu, Qiao-Quan

    2016-07-01

    Rice (Oryza sativa L.), a major staple crop worldwide, has limited levels of the essential amino acid lysine. We previously produced engineered rice with increased lysine content by expressing bacterial aspartate kinase and dihydrodipicolinate synthase and inhibiting rice lysine ketoglutarate reductase/saccharopine dehydrogenase activity. However, the grain quality, field performance, and integration patterns of the transgenes in these lysine-enriched lines remain unclear. In the present study, we selected several elite transgenic lines with endosperm-specific or constitutive regulation of the above key enzymes but lacking the selectable marker gene. All target transgenes were integrated into the intragenic region in the rice genome. Two pyramid transgenic lines (High Free Lysine; HFL1 and HFL2) with free lysine levels in seeds up to 25-fold that of wild type were obtained via a combination of the above two transgenic events. We observed a dramatic increase in total free amino acids and a slight increase in total protein content in both pyramid lines. Moreover, the general physicochemical properties were improved in pyramid transgenic rice, but the starch composition was not affected. Field trials indicated that the growth of HFL transgenic rice was normal, except for a slight difference in plant height and grain colour. Taken together, these findings will be useful for the potential commercialization of high-lysine transgenic rice.

  18. Fatty acids, essential oil and phenolics composition of Silybum marianum seeds and their antioxidant activities.

    PubMed

    Mhamdi, Baya; Abbassi, Feten; Smaoui, Abderrazak; Abdelly, Chedly; Marzouk, Brahim

    2016-05-01

    The presentstudydescribes the biochemical evaluation of Silybum marianum seed. The analysis of essential oil composition of Silybum marianum seed by Gas Chromatography-Mass Spectrometry GC-MS showed the presence of14 volatile components with the predominance of γ-cadinene (49.8%) and α-pinene (24.5%). Whereas, the analysis of fatty acids composition, showed the predominance of linoleic (50.5%) and oleic (30.2%) acids. Silybum marainum presented also an important polyphenol contents with 29mgGAE/g DW, a good antiradical activity (CI(50)=39μg/ml) but a lower reducing power ability. Flavonoid and condensed tannin contents were about 3.39mg EC/g DW and 1.8mg EC/gDW, respectively. The main phenolic compounds identified by RP-HPLC, were silybin A (12.2%), silybin B (17.67%), isosilybin A (21.9%), isosilybin B (12.8%), silychristin (7.9%) andsilydianin (7.5%).

  19. Single aromatic residue location alters nucleic acid binding and chaperone function of FIV nucleocapsid protein

    PubMed Central

    Wu, Hao; Wang, Wei; Naiyer, Nada; Fichtenbaum, Eric; Qualley, Dominic F.; McCauley, Micah J.; Gorelick, Robert J.; Rouzina, Ioulia; Musier-Forsyth, Karin; Williams, Mark C.

    2014-01-01

    Feline immunodeficiency virus (FIV) is a retrovirus that infects domestic cats, and is an excellent animal model for human immunodeficiency virus type 1 (HIV-1) pathogenesis. The nucleocapsid (NC) protein is critical for replication in both retroviruses. FIV NC has several structural features that differ from HIV-1 NC. While both NC proteins have a single conserved aromatic residue in each of the two zinc fingers, the aromatic residue on the second finger of FIV NC is located on the opposite C-terminal side relative to its location in HIV-1 NC. In addition, whereas HIV-1 NC has a highly charged cationic N-terminal tail and a relatively short C-terminal extension, the opposite is true for FIV NC. To probe the impact of these differences on the nucleic acid (NA) binding and chaperone properties of FIV NC, we carried out ensemble and single-molecule assays with wild-type (WT) and mutant proteins. The ensemble studies show that FIV NC binding to DNA is strongly electrostatic, with a higher effective charge than that observed for HIV-1 NC. The C-terminal basic domain contributes significantly to the NA binding capability of FIV NC. In addition, the non-electrostatic component of DNA binding is much weaker for FIV NC than for HIV-1 NC. Mutation of both aromatic residues in the zinc fingers to Ala (F12A/W44A) further increases the effective charge of FIV NC and reduces its non-electrostatic binding affinity. Interestingly, switching the location of the C-terminal aromatic residue to mimic the HIV-1 NC sequence (N31W/W44A) reduces the effective charge of FIV NC and increases its non-electrostatic binding affinity to values similar to HIV-1 NC. Consistent with the results of these ensemble studies, single-molecule DNA stretching studies show that while WT FIV NC has reduced stacking capability relative to HIV-1 NC, the aromatic switch mutant recovers the ability to intercalate between the DNA bases. Our results demonstrate that altering the position of a single aromatic

  20. Conserved Amino Acid Residues of the NuoD Segment Important for Structure and Function of Escherichia coli NDH-1 (Complex I)

    PubMed Central

    2015-01-01

    The NuoD segment (homologue of mitochondrial 49 kDa subunit) of the proton-translocating NADH:quinone oxidoreductase (complex I/NDH-1) from Escherichia coli is in the hydrophilic domain and bears many highly conserved amino acid residues. The three-dimensional structural model of NDH-1 suggests that the NuoD segment, together with the neighboring subunits, constitutes a putative quinone binding cavity. We used the homologous DNA recombination technique to clarify the role of selected key amino acid residues of the NuoD segment. Among them, residues Tyr273 and His224 were considered candidates for having important interactions with the quinone headgroup. Mutant Y273F retained partial activity but lost sensitivity to capsaicin-40. Mutant H224R scarcely affected the activity, suggesting that this residue may not be essential. His224 is located in a loop near the N-terminus of the NuoD segment (Gly217–Phe227) which is considered to form part of the quinone binding cavity. In contrast to the His224 mutation, mutants G217V, P218A, and G225V almost completely lost the activity. One region of this loop is positioned close to a cytosolic loop of the NuoA subunit in the membrane domain, and together they seem to be important in keeping the quinone binding cavity intact. The structural role of the longest helix in the NuoD segment located behind the quinone binding cavity was also investigated. Possible roles of other highly conserved residues of the NuoD segment are discussed. PMID:25545070

  1. Identification of amino acid residues involved in substrate specificity of plant acyl-ACP thioesterases using a bioinformatics-guided approach

    PubMed Central

    Mayer, Kimberly M; Shanklin, John

    2007-01-01

    Background The large amount of available sequence information for the plant acyl-ACP thioesterases (TEs) made it possible to use a bioinformatics-guided approach to identify amino acid residues involved in substrate specificity. The Conserved Property Difference Locator (CPDL) program allowed the identification of putative specificity-determining residues that differ between the FatA and FatB TE classes. Six of the FatA residue differences identified by CPDL were incorporated into the FatB-like parent via site-directed mutagenesis and the effect of each on TE activity was determined. Variants were expressed in E. coli strain K27 that allows determination of enzyme activity by GCMS analysis of fatty acids released into the medium. Results Substitutions at four of the positions (74, 86, 141, and 174) changed substrate specificity to varying degrees while changes at the remaining two positions, 110 and 221, essentially inactivated the thioesterase. The effects of substitutions at positions 74, 141, and 174 (3-MUT) or 74, 86, 141, 174 (4-MUT) were not additive with respect to specificity. Conclusion Four of six putative specificity determining positions in plant TEs, identified with the use of CPDL, were validated experimentally; a novel colorimetric screen that discriminates between active and inactive TEs is also presented. PMID:17201914

  2. Intra-molecular cross-linking of acidic residues for protein structure studies.

    SciTech Connect

    Kruppa, Gary Hermann; Young, Malin M.; Novak, Petr; Schoeniger, Joseph S.

    2005-03-01

    Intra-molecular cross-linking has been suggested as a method of obtaining distance constraints that would be useful in developing structural models of proteins. Recent work published on intra-molecular cross-linking for protein structural studies has employed commercially available primary amine selective reagents that can cross-link lysine residues to other lysine residues or the amino terminus. Previous work using these cross-linkers has shown that for several proteins of known structure, the number of cross-links that can be obtained experimentally may be small compared to what would be expected from the known structure, due to the relative reactivity, distribution, and solvent accessibility of the lysines in the protein sequence. To overcome these limitations we have investigated the use of cross-linking reagents that can react with other reactive sidechains in proteins. We used 1-Ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride (EDC) to activate the carboxylic acid containing residues, aspartic acid (D), glutamic acid (E), and the carboxy terminus (O), for cross-linking reactions. Once activated, the DEO sidechains can react to form 'zero-length' cross-links with nearby primary amine containing resides, lysines (K) and the amino terminus (X), via the formation of a new amide bond. We also show that the EDC-activated DEO sidechains can be cross-linked to each other using dihydrazides, two hydrazide moieties connected by an alkyl cross-linker ann of variable length. Using these reagents, we have found three new 'zero-length' cross-links in ubiquitin consistent with its known structure (M1-E16, M1-E18, and K63-E64). Using the dihydrazide cross-linkers, we have identified 2 new cross-links (D21-D32 and E24-D32) unambiguously. Using a library of dihydrazide cross-linkers with varying arm length, we have shown that there is a minimum arm length required for the DEO-DEO cross-links of 5.8 angstroms. These results show that additional structural information

  3. Arg²³⁵ is an essential catalytic residue of Bacillus pumilus DKS1 pectate lyase to degum ramie fibre.

    PubMed

    Basu, Snehasish; Roy, Arunava; Ghosh, Abhrajyoti; Bera, Amit; Chattopadhyay, Dhrubajyoti; Chakrabarti, Krishanu

    2011-02-01

    After 24 h of incubation with only purified pectate lyase isolated from Bacillus pumilus DKS1 (EF467045), the weight loss of the ramie fibre was found to be 25%. To know the catalytic residue of pectate lyase the pel gene encoding a pectate lyase from the strain Bacillus pumilus DKS1 was cloned in E. coli XL1Blue and expressed in E. coli BL21 (DE3) pLysS. The pel gene was sequenced and showed 1032 bp length. After purification using CM-Sepharose the enzyme showed molecular weight of 35 kDa and maximal enzymatic activity was observed at 60°C and a pH range of 8.5-9.0. Both Ca²(+) and Mn²(+) ions were required for activity on Na-pectate salt substrates, while the enzyme was strongly inhibited by Zn²(+) and EDTA. The deduced nucleotide sequence of the DKS1 pectate lyase (EU652988) showed 90% homology to pectate lyases from Bacillus pumilus SAFR-032 (CP000813). The 3D structure as well as the catalytic residues was predicted using EasyPred software and Catalytic Site Atlas (CSA), respectively. Site directed mutagenesis confirmed that arginine is an essential catalytic residue of DKS1 pectate lyase.

  4. Transmembrane carboxyl residues are essential for cation-dependent function in the gastric H,K-ATPase.

    PubMed

    Rabon, E C; Hoggatt, M; Smillie, K

    1996-12-13

    The K+-dependent ATPase activity of the H,K-ATPase was irreversibly inhibited by the carboxyl activating reagent, dicyclohexylcarbodiimide (DCCD). The inhibition was first order and displayed a concentration dependence with the K0.5 (DCCD) = 0.65 +/- 0.04 mM. KCl protected 70% of the ATPase activity from DCCD-dependent inhibition in a concentration-dependent manner with a K0.5 (K+) = 0.58 +/- 0.1 mM KCl. DCCD modification selectively inhibited the K+-dependent rather than ATP-dependent partial reactions including eosin fluorescence responses and ligand-stabilized initial tryptic cleavage patterns of the membrane-associated enzyme. DCCD modification also inhibited the binding of 86Rb+ and the fluorescent responses of the K+-competitive, fluorescent inhibitor 1-(2-methylphenyl)-4-methylamino-6-methyl-2, 3-dihydropyrrolo[3,2-c]quinoline. [14C]DCCD was incorporated into the H,K-ATPase in a time course identical to that describing the inactivation of the K+-dependent ATPase activity of the H,K-ATPase. A component of the [14C]DCCD incorporated into the H,K-ATPase was K+-sensitive where K+ reduced the [14C]DCCD incorporated into the enzyme by 1.6 nmol of [14C]DCCD/mg of protein. Membrane-associated tryptic peptides resolved from the [14C]DCCD-modified H,K-ATPase exhibited various K+ sensitivities with peptides at 23, 9.6, 8.2, 7.1, and 6.1 kDa containing 10-78%, 23-52%, 24-36%, 2%, and 3-4% K+-sensitivity, respectively. The N-terminal sequence of the K+-sensitive, approximately 23- and 9.6-kDa peptides was LVNE857, a C-terminal fragment of the ATPase alpha-subunit. The mass of the smaller peptide limited the residue assignment to the transmembrane M7/M8 domains and an intervening extracytoplasmic loop. An N-terminal sequence, SD840IM, was obtained from a 3.3-kDa, [14C]DCCD-labeled peptide resolved from a V8 digest of the partially purified alpha-subunit. This mass was sufficient to include LVNE but would exclude M8 and the intervening loop between M7 and M8. Glu857 is a

  5. Nitrate and Nitrite Determination in Gunshot Residue Samples by Capillary Electrophoresis in Acidic Run Buffer().

    PubMed

    Erol, Özge Ö; Erdoğan, Behice Y; Onar, Atiye N

    2017-03-01

    Simultaneous determination of nitrate and nitrite in gunshot residue has been conducted by capillary electrophoresis using an acidic run buffer (pH 3.5). In previously developed capillary electrophoretic methods, alkaline pH separation buffers were used where nitrite and nitrate possess similar electrophoretic mobility. In this study, the electroosmotic flow has been reversed by using low pH running buffer without any additives. As a result of reversing the electroosmotic flow, very fast analysis has been actualized, well-defined and separated ion peaks emerge in less than 4 min. Besides, the limit of detection was improved by employing large volume sample stacking. Limit of detection values were 6.7 and 4.3 μM for nitrate and nitrite, respectively. In traditional procedure, mechanical agitation is employed for extraction, while in this work the extraction efficiency of ultrasound mixing for 30 min was found sufficient. The proposed method was successfully applied to authentic gunshot residue samples.

  6. Allosteric Inhibition of Phosphoenolpyruvate Carboxylases is Determined by a Single Amino Acid Residue in Cyanobacteria

    PubMed Central

    Takeya, Masahiro; Hirai, Masami Yokota; Osanai, Takashi

    2017-01-01

    Phosphoenolpyruvate carboxylase (PEPC) is an important enzyme for CO2 fixation and primary metabolism in photosynthetic organisms including cyanobacteria. The kinetics and allosteric regulation of PEPCs have been studied in many organisms, but the biochemical properties of PEPC in the unicellular, non-nitrogen-fixing cyanobacterium Synechocystis sp. PCC 6803 have not been clarified. In this study, biochemical analysis revealed that the optimum pH and temperature of Synechocystis 6803 PEPC proteins were 7.3 and 30 °C, respectively. Synechocystis 6803 PEPC was found to be tolerant to allosteric inhibition by several metabolic effectors such as malate, aspartate, and fumarate compared with other cyanobacterial PEPCs. Comparative sequence and biochemical analysis showed that substitution of the glutamate residue at position 954 with lysine altered the enzyme so that it was inhibited by malate, aspartate, and fumarate. PEPC of the nitrogen-fixing cyanobacterium Anabaena sp. PCC 7120 was purified, and its activity was inhibited in the presence of malate. Substitution of the lysine at position 946 (equivalent to position 954 in Synechocystis 6803) with glutamate made Anabaena 7120 PEPC tolerant to malate. These results demonstrate that the allosteric regulation of PEPC in cyanobacteria is determined by a single amino acid residue, a characteristic that is conserved in different orders. PMID:28117365

  7. Salicylic acid and jasmonic acid are essential for systemic resistance against tobacco mosaic virus in Nicotiana benthamiana.

    PubMed

    Zhu, Feng; Xi, De-Hui; Yuan, Shu; Xu, Fei; Zhang, Da-Wei; Lin, Hong-Hui

    2014-06-01

    Systemic resistance is induced by pathogens and confers protection against a broad range of pathogens. Recent studies have indicated that salicylic acid (SA) derivative methyl salicylate (MeSA) serves as a long-distance phloem-mobile systemic resistance signal in tobacco, Arabidopsis, and potato. However, other experiments indicate that jasmonic acid (JA) is a critical mobile signal. Here, we present evidence suggesting both MeSA and methyl jasmonate (MeJA) are essential for systemic resistance against Tobacco mosaic virus (TMV), possibly acting as the initiating signals for systemic resistance. Foliar application of JA followed by SA triggered the strongest systemic resistance against TMV. Furthermore, we use a virus-induced gene-silencing-based genetics approach to investigate the function of JA and SA biosynthesis or signaling genes in systemic response against TMV infection. Silencing of SA or JA biosynthetic and signaling genes in Nicotiana benthamiana plants increased susceptibility to TMV. Genetic experiments also proved the irreplaceable roles of MeSA and MeJA in systemic resistance response. Systemic resistance was compromised when SA methyl transferase or JA carboxyl methyltransferase, which are required for MeSA and MeJA formation, respectively, were silenced. Moreover, high-performance liquid chromatography-mass spectrometry analysis indicated that JA and MeJA accumulated in phloem exudates of leaves at early stages and SA and MeSA accumulated at later stages, after TMV infection. Our data also indicated that JA and MeJA could regulate MeSA and SA production. Taken together, our results demonstrate that (Me)JA and (Me)SA are required for systemic resistance response against TMV.

  8. A synthetic amino acid residue containing a new oligopeptide-based photosensitive fluorescent organogel.

    PubMed

    Maiti, Dibakar Kumar; Banerjee, Arindam

    2013-01-01

    A synthetic amino acid (with a stilbene residue in the main chain) containing a tripeptide-based organogelator has been discovered. This peptide-based synthetic molecule 1 self-assembles in various organic solvents to form an organogel. The gel has been thoroughly characterized by using various microscopic techniques including field-emission scanning electron microscopy (FESEM), atomic force microscopy (AFM), X-ray diffraction (XRD), UV-visible and fluorescence spectroscopy, and rheology. Morphological investigations using FESEM and AFM show a nanofibrillar network structure. Interestingly, the organogel is photoresponsive and a gel-sol transition occurred by irradiating the gel with UV light of 365 nm for 2 h as shown by the UV and fluorescence study. This photoresponsive fluorescent gel holds promise for new peptide-based soft materials with interesting applications.

  9. Characterisation of the products from pyrolysis of residues after acid hydrolysis of Miscanthus.

    PubMed

    Melligan, F; Dussan, K; Auccaise, R; Novotny, E H; Leahy, J J; Hayes, M H B; Kwapinski, W

    2012-03-01

    Platform chemicals such as furfural and hydroxymethylfurfural are major products formed during the acid hydrolysis of lignocellulosic biomass in second generation biorefining processes. Solid hydrolysis residues (HR) can amount to 50 wt.% of the starting biomass materials. Pyrolysis of the HRs gives rise to biochar, bio-liquids, and gases. Time and temperature were variables during the pyrolysis of HRs in a fixed bed tubular reactor, and both parameters have major influences on the amounts and properties of the products. Biochar, with potential for carbon sequestration and soil conditioning, composed about half of the HR pyrolysis product. The amounts (11-20 wt.%) and compositions (up to 77% of phenols in organic fraction) of the bio-liquids formed suggest that these have little value as fuels, but could be sources of phenols, and the gas can have application as a fuel.

  10. Site-Specific Pyrolysis Induced Cleavage at Aspartic Acid Residue in Peptides and Proteins

    PubMed Central

    Zhang, Shaofeng; Basile, Franco

    2011-01-01

    A simple and site-specific non-enzymatic method based on pyrolysis has been developed to cleave peptides and proteins. Pyrolytic cleavage was found to be specific and rapid as it induced a cleavage at the C-terminal side of aspartic acid in the temperature range of 220–250 °C in 10 seconds. Electrospray Ionization (ESI) mass spectrometry (MS) and tandem-MS (MS/MS) were used to characterize and identify pyrolysis cleavage products, confirming that sequence information is conserved after the pyrolysis process in both peptides and protein tested. This suggests that pyrolysis-induced cleavage at aspartyl residues can be used as a rapid protein digestion procedure for the generation of sequence specific protein biomarkers. PMID:17388620

  11. Modeling, Substrate Docking, and Mutational Analysis Identify Residues Essential for the Function and Specificity of a Eukaryotic Purine-Cytosine NCS1 Transporter*

    PubMed Central

    Krypotou, Emilia; Kosti, Vasiliki; Amillis, Sotiris; Myrianthopoulos, Vassilios; Mikros, Emmanuel; Diallinas, George

    2012-01-01

    The recent elucidation of crystal structures of a bacterial member of the NCS1 family, the Mhp1 benzyl-hydantoin permease from Microbacterium liquefaciens, allowed us to construct and validate a three-dimensional model of the Aspergillus nidulans purine-cytosine/H+ FcyB symporter. The model consists of 12 transmembrane α-helical, segments (TMSs) and cytoplasmic N- and C-tails. A distinct core of 10 TMSs is made of two intertwined inverted repeats (TMS1–5 and TMS6–10) that are followed by two additional TMSs. TMS1, TMS3, TMS6, and TMS8 form an open cavity that is predicted to host the substrate binding site. Based on primary sequence alignment, three-dimensional topology, and substrate docking, we identified five residues as potentially essential for substrate binding in FcyB; Ser-85 (TMS1), Trp-159, Asn-163 (TMS3), Trp-259 (TMS6), and Asn-354 (TMS8). To validate the role of these and other putatively critical residues, we performed a systematic functional analysis of relevant mutants. We show that the proposed substrate binding residues, plus Asn-350, Asn-351, and Pro-353 are irreplaceable for FcyB function. Among these residues, Ser-85, Asn-163, Asn-350, Asn-351, and Asn-354 are critical for determining the substrate binding affinity and/or the specificity of FcyB. Our results suggest that Ser-85, Asn-163, and Asn-354 directly interact with substrates, Trp-159 and Trp-259 stabilize binding through π-π stacking interactions, and Pro-353 affects the local architecture of substrate binding site, whereas Asn-350 and Asn-351 probably affect substrate binding indirectly. Our work is the first systematic approach to address structure-function-specificity relationships in a eukaryotic member of NCS1 family by combining genetic and computational approaches. PMID:22969088

  12. Resistance of essential fatty acid-deficient rats to endotoxin-induced increases in vascular permeability

    SciTech Connect

    Li, E.J.; Cook, J.A.; Spicer, K.M.; Wise, W.C.; Rokach, J.; Halushka, P.V. )

    1990-06-01

    Resistance to endotoxin in essential fatty acid-deficient (EFAD) rats is associated with reduced synthesis of certain arachidonic acid metabolites. It was hypothesized that EFAD rats would manifest decreased vascular permeability changes during endotoxemia as a consequence of reduced arachidonic acid metabolism. To test this hypothesis, changes in hematocrit (HCT) and mesenteric localization rate of technetium-labeled human serum albumin (99mTc-HSA) and red blood cells (99mTc-RBC) were assessed in EFAD and normal rats using gamma-camera imaging. Thirty minutes after Salmonella enteritidis endotoxin, EFAD rats exhibited less hemoconcentration as determined by % HCT than normal rats. Endotoxin caused a less severe change in permeability index in the splanchnic region in EFAD rats than in normal rats (1.2 +/- 0.6 x 10(-3)min-1 vs. 4.9 +/- 1.7 x 10(-3)min-1 respectively, P less than 0.05). In contrast to 99mTc-HSA, mesenteric localization of 99mTc-RBC was not changed by endotoxin in control or EFAD rats. Supplementation with ethyl-arachidonic acid did not enhance susceptibility of EFAD rats to endotoxin-induced splanchnic permeability to 99mTc-HSA. Leukotrienes have been implicated as mediators of increased vascular permeability in endotoxin shock. Since LTC3 formation has been reported to be increased in EFA deficiency, we hypothesized that LTC3 may be less potent than LTC4. Thus the effect of LTC3 on mean arterial pressure and permeability was compared to LTC4 in normal rats. LTC3-induced increases in peak mean arterial pressure were less than LTC4 at 10 micrograms/kg (39 +/- 5 mm Hg vs. 58 +/- 4 mm Hg respectively, P less than 0.05) and at 20 micrograms/kg (56 +/- 4 mm Hg vs. 75 +/- 2 mm Hg respectively, P less than 0.05). LY171883 (30 mg/kg), an LTD4/E4 receptor antagonist, attenuated the pressor effect of LTC4, LTD4, and LTC3.

  13. Residue Geometry Networks: A Rigidity-Based Approach to the Amino Acid Network and Evolutionary Rate Analysis

    PubMed Central

    Fokas, Alexander S.; Cole, Daniel J.; Ahnert, Sebastian E.; Chin, Alex W.

    2016-01-01

    Amino acid networks (AANs) abstract the protein structure by recording the amino acid contacts and can provide insight into protein function. Herein, we describe a novel AAN construction technique that employs the rigidity analysis tool, FIRST, to build the AAN, which we refer to as the residue geometry network (RGN). We show that this new construction can be combined with network theory methods to include the effects of allowed conformal motions and local chemical environments. Importantly, this is done without costly molecular dynamics simulations required by other AAN-related methods, which allows us to analyse large proteins and/or data sets. We have calculated the centrality of the residues belonging to 795 proteins. The results display a strong, negative correlation between residue centrality and the evolutionary rate. Furthermore, among residues with high closeness, those with low degree were particularly strongly conserved. Random walk simulations using the RGN were also successful in identifying allosteric residues in proteins involved in GPCR signalling. The dynamic function of these residues largely remain hidden in the traditional distance-cutoff construction technique. Despite being constructed from only the crystal structure, the results in this paper suggests that the RGN can identify residues that fulfil a dynamical function. PMID:27623708

  14. Residue Geometry Networks: A Rigidity-Based Approach to the Amino Acid Network and Evolutionary Rate Analysis

    NASA Astrophysics Data System (ADS)

    Fokas, Alexander S.; Cole, Daniel J.; Ahnert, Sebastian E.; Chin, Alex W.

    2016-09-01

    Amino acid networks (AANs) abstract the protein structure by recording the amino acid contacts and can provide insight into protein function. Herein, we describe a novel AAN construction technique that employs the rigidity analysis tool, FIRST, to build the AAN, which we refer to as the residue geometry network (RGN). We show that this new construction can be combined with network theory methods to include the effects of allowed conformal motions and local chemical environments. Importantly, this is done without costly molecular dynamics simulations required by other AAN-related methods, which allows us to analyse large proteins and/or data sets. We have calculated the centrality of the residues belonging to 795 proteins. The results display a strong, negative correlation between residue centrality and the evolutionary rate. Furthermore, among residues with high closeness, those with low degree were particularly strongly conserved. Random walk simulations using the RGN were also successful in identifying allosteric residues in proteins involved in GPCR signalling. The dynamic function of these residues largely remain hidden in the traditional distance-cutoff construction technique. Despite being constructed from only the crystal structure, the results in this paper suggests that the RGN can identify residues that fulfil a dynamical function.

  15. Differential contribution of basic residues to HIV-1 nucleocapsid protein’s nucleic acid chaperone function and retroviral replication

    PubMed Central

    Wu, Hao; Mitra, Mithun; Naufer, M. Nabuan; McCauley, Micah J.; Gorelick, Robert J.; Rouzina, Ioulia; Musier-Forsyth, Karin; Williams, Mark C.

    2014-01-01

    The human immunodeficiency virus type 1 (HIV-1) nucleocapsid (NC) protein contains 15 basic residues located throughout its 55-amino acid sequence, as well as one aromatic residue in each of its two CCHC-type zinc finger motifs. NC facilitates nucleic acid (NA) rearrangements via its chaperone activity, but the structural basis for this activity and its consequences in vivo are not completely understood. Here, we investigate the role played by basic residues in the N-terminal domain, the N-terminal zinc finger and the linker region between the two zinc fingers. We use in vitro ensemble and single-molecule DNA stretching experiments to measure the characteristics of wild-type and mutant HIV-1 NC proteins, and correlate these results with cell-based HIV-1 replication assays. All of the cationic residue mutations lead to NA interaction defects, as well as reduced HIV-1 infectivity, and these effects are most pronounced on neutralizing all five N-terminal cationic residues. HIV-1 infectivity in cells is correlated most strongly with NC’s NA annealing capabilities as well as its ability to intercalate the DNA duplex. Although NC’s aromatic residues participate directly in DNA intercalation, our findings suggest that specific basic residues enhance these interactions, resulting in optimal NA chaperone activity. PMID:24293648

  16. Amino acid residues 201-205 in C-terminal acidic tail region plays a crucial role in antibacterial activity of HMGB1

    PubMed Central

    2009-01-01

    Background Antibacterial activity is a novel function of high-mobility group box 1 (HMGB1). However, the functional site for this new effect is presently unknown. Methods and Results In this study, recombinant human HMGB1 A box and B box (rHMGB1 A box, rHMGB1 B box), recombinant human HMGB1 (rHMGB1) and the truncated C-terminal acidic tail mutant (tHMGB1) were prepared by the prokaryotic expression system. The C-terminal acidic tail (C peptide) was synthesized, which was composed of 30 amino acid residues. Antibacterial assays showed that both the full length rHMGB1 and the synthetic C peptide alone could efficiently inhibit bacteria proliferation, but rHMGB1 A box and B box, and tHMGB1 lacking the C-terminal acidic tail had no antibacterial function. These results suggest that C-terminal acidic tail is the key region for the antibacterial activity of HMGB1. Furthermore, we prepared eleven different deleted mutants lacking several amino acid residues in C-terminal acidic tail of HMGB1. Antibacterial assays of these mutants demonstrate that the amino acid residues 201-205 in C-terminal acidic tail region is the core functional site for the antibacterial activity of the molecule. Conclusion In sum, these results define the key region and the crucial site in HMGB1 for its antibacterial function, which is helpful to illustrating the antibacterial mechanisms of HMGB1. PMID:19751520

  17. Selective conversion of cellulose in corncob residue to levulinic acid in an aluminum trichloride-sodium chloride system.

    PubMed

    Li, Jianmei; Jiang, Zhicheng; Hu, Libin; Hu, Changwei

    2014-09-01

    Increased energy consumption and environmental concerns have driven efforts to produce chemicals from renewable biomass with high selectivity. Here, the selective conversion of cellulose in corncob residue, a process waste from the production of xylose, to levulinic acid was carried out using AlCl3 as catalyst and NaCl as promoter by a hydrothermal method at relatively low temperature. A levulinic acid yield of 46.8 mol% was obtained, and the total selectivity to levulinic acid with formic acid was beyond 90%. NaCl selectively promoted the dissolution of cellulose from corncob residue, and significantly improved the yield and selectivity to levulinic acid by inhibiting lactic acid formation in the subsequent dehydration process. Owing to the salt effect of NaCl, the obtained levulinic acid could be efficiently extracted to tetrahydrofuran from aqueous solution. The aqueous solution with AlCl3 and NaCl could be recycled 4 times. Because of the limited conversion of lignin, this process allows for the production of levulinic acid with high selectivity directly from corncob residue in a simple separation process.

  18. Differential expression of the α2,3-sialic acid residues in breast cancer is associated with metastatic potential.

    PubMed

    Cui, Hongxia; Lin, Yu; Yue, Liling; Zhao, Xuemei; Liu, Jicheng

    2011-05-01

    Aberrant sialylation is closely associated with the malignant phenotype of cancer cells and metastatic potential. However, the precise nature of the molecules in breast cancers has not been unveiled. In this study, we investigated the expression levels of α2,3-sialic acid residues of 50 primary tumor cases, 50 pair-matched lymph node metastasis tumor samples and in the MDA-MB-231, T-47D and MCF-7 breast cancer cell lines with different metastatic potential. The expression of α2,3-sialic acid residues was analyzed by histochemistry, cytochemistry and flow cytometry with Maackia amurensis lectin (MAL). The invasion and migration abilities of cells were examined using cell adhesion and transwell in vitro assays. Pair-matched lymph node metastasis tumor samples exhibited higher levels of expression of α2,3-sialic acid residues compared to that of primary tumors (P=0.0432). Furthermore, of 38 tumors cases in T1/T2 stages, 31 (81.58%) had weak staining for MAL, which specifically binds to α2,3-sialic acid residues, whereas of 12 tumor cases in T3/T4 stages, only 1 (8.33%) had weak reactions for MAL. The highly metastatic breast cancer cell line MDA-MB-231 exhibited the strongest binding to MAL and the highest expression levels of α2,3-sialic acid residues among the selected cell lines, depending on mRNA expression levels of α2,3-sialyltransferase gene. The adhesion, invasion and migration activities confirmed that MDA-MB-231 exhibited the greater cell adhesion to, migration toward and invasion to Matrigel. Taken together, the high expression of α2,3-sialic acid residues in breast cancer was associated with metastatic potential. This property may be important for developing new therapeutic approaches for breast cancer.

  19. Monomethyl Branched-Chain Fatty Acids Play an Essential Role in Caenorhabditis elegans Development

    PubMed Central

    Crawford, Quinn T; Seiber, Matt; Wang, Cun-Yu

    2004-01-01

    Monomethyl branched-chain fatty acids (mmBCFAs) are commonly found in many organisms from bacteria to mammals. In humans, they have been detected in skin, brain, blood, and cancer cells. Despite a broad distribution, mmBCFAs remain exotic in eukaryotes, where their origin and physiological roles are not understood. Here we report our study of the function and regulation of mmBCFAs in Caenorhabditis elegans, combining genetics, gas chromatography, and DNA microarray analysis. We show that C. elegans synthesizes mmBCFAs de novo and utilizes the long-chain fatty acid elongation enzymes ELO-5 and ELO-6 to produce two mmBCFAs, C15ISO and C17ISO. These mmBCFAs are essential for C. elegans growth and development, as suppression of their biosynthesis results in a growth arrest at the first larval stage. The arrest is reversible and can be overcome by feeding the arrested animals with mmBCFA supplements. We show not only that the levels of C15ISO and C17ISO affect the expression of several genes, but also that the activities of some of these genes affect biosynthesis of mmBCFAs, suggesting a potential feedback regulation. One of the genes, lpd-1, encodes a homolog of a mammalian sterol regulatory element-binding protein (SREBP 1c). We present results suggesting that elo-5 and elo-6 may be transcriptional targets of LPD-1. This study exposes unexpected and crucial physiological functions of C15ISO and C17ISO in C. elegans and suggests a potentially important role for mmBCFAs in other eukaryotes. PMID:15340492

  20. A new method for the study of essential fatty acid requirements in fish larvae.

    PubMed

    Morais, Sofia; Conceição, Luís E C

    2009-05-01

    This study describes a methodology with potential application in the estimation of essential fatty acid (EFA) requirements of fish larvae. Senegalese sole (Solea senegalensis) larvae were fed, from 16 days after hatching (DAH), on Artemia enriched with different oils, inducing graded dietary concentrations of DHA: (1) soyabean oil, containing no measurable amounts of DHA (NDHA); (2) fish oil, inducing a medium DHA level (MDHA, 3 g DHA/100 g fatty acids); and (3) a mixture of Easy DHA Selco and Microfeed, resulting in high DHA content (HDHA, 8 g/100 g). At 28 DAH a metabolic trial was conducted where larvae were tube fed [1-(14) C]DHA, in order to determine its absorption, retention in the gut and body tissues, as well as its oxidation. At 23 DAH the HDHA treatment induced a significantly higher larval growth, while at 32 DAH significant differences were only found between the NDHA and HDHA treatments. The absorption of tube-fed [1-(14) C]DHA was extremely high (94-95 %) and independent of feeding regime. However, in larvae fed NDHA Artemia, a significantly higher amount of label was retained in the gut compartment and a concurrently lower retention was measured in the body. A significantly higher proportion of the absorbed DHA label was oxidized in larvae fed HDHA, compared to NDHA. Based on these results, we suggest that increasing dietary supply of DHA above the larval requirement level results in its increased oxidation for energy purposes and we propose potential applications of the tube feeding methodology using radiolabelled EFA in conjunction with dose-response studies.

  1. Identification by site-directed mutagenesis of three essential histidine residues in membrane dipeptidase, a novel mammalian zinc peptidase.

    PubMed Central

    Keynan, S; Hooper, N M; Turner, A J

    1997-01-01

    Membrane dipeptidase (EC 3.4.13.19) is a plasma membrane zinc peptidase that is involved in the renal metabolism of glutathione and its conjugates, such as leukotriene D4. The enzyme lacks the classical signatures of other zinc-dependent hydrolases and shows no homology with any other mammalian protein. We have used site-directed mutagenesis to explore the roles of five histidine residues in pig membrane dipeptidase that are conserved among mammalian species. When expressed in COS-1 cells, the mutants H49K and H128L exhibited a specific activity and Km for the substrate Gly-D-Phe comparable with those of the wild-type enzyme. However, the mutants H20L, H152L and H198K were inactive, but were expressed at the cell surface at equivalent levels to the wild-type, as assessed by immunoblotting and immunofluorescence. These three mutants were compared with regard to their ability to bind to the competitive inhibitor cilastatin, which binds with equal efficacy to native and EDTA-treated pig kidney membrane dipeptidase. Expressed wild-type enzyme and mutants H20L and H198K were efficiently bound by cilastatin-Sepharose, but H152L failed to bind. Thus His-152 appears to be involved in the binding of substrate or inhibitor, whereas His-20 and His-198 appear to be involved in catalysis. Membrane dipeptidase shares some similarity with a dipeptidase recently cloned from Acinetobacter calcoaceticus. In particular, His-20 and His-198 of membrane dipeptidase are conserved in the bacterial enzyme, as are Glu-125 and His-219, previously shown to be required for catalytic activity. PMID:9337849

  2. The ACVD task force on canine atopic dermatitis (XXIII): are essential fatty acids effective?

    PubMed

    Olivry, T; Marsella, R; Hillier, A

    2001-09-20

    Essential fatty acids (EFAs) exhibit the potential to affect allergic inflammation through the modulation of prostaglandin and leukotriene production, the inhibition of cellular activation and cytokine secretion as well as the alteration of the composition and function of the epidermal lipid barrier. Because of these multi-faceted effects, EFA have been proposed for treatment of canine atopic dermatitis (AD) since 1987. To date, more than 20 trials have been performed, reporting the efficacy of either oral EFA supplements or EFA-rich diets. Unfortunately, most of these studies were found to exhibit one or more of the following deficiencies: heterogeneity of diagnoses used as inclusion criteria, short duration of supplementation, lack of randomization of treatment allocation, lack of blinding of investigators and/or owners, lack of placebo or active controls, lack of documentation of plasma or skin EFA profiles during supplementation, as well as lack of standardization of the basal diets or supplements which could have provided additional EFA. Consequently, there is presently insufficient evidence to recommend for or against the use of EFA to control clinical signs of canine AD. Evidence of efficacy must await the performance of blinded, randomized and controlled trials of at least 3 months duration in which diets are identical for all of study subjects. In these trials, clinical efficacy should be evaluated in relation to plasma and cutaneous EFA treatment-induced alterations.

  3. Hypercortisolemia alters muscle protein anabolism following ingestion of essential amino acids

    NASA Technical Reports Server (NTRS)

    Paddon-Jones, Douglas; Sheffield-Moore, Melinda; Creson, Daniel L.; Sanford, Arthur P.; Wolf, Steven E.; Wolfe, Robert R.; Ferrando, Arny A.

    2003-01-01

    Debilitating injury is accompanied by hypercortisolemia, muscle wasting, and disruption of the normal anabolic response to food. We sought to determine whether acute hypercortisolemia alters muscle protein metabolism following ingestion of a potent anabolic stimulus: essential amino acids (EAA). A 27-h infusion (80 microg. kg(-1). h(-1)) of hydrocortisone sodium succinate mimicked cortisol (C) levels accompanying severe injury (>30 microg/dl), (C + AA; n = 6). The control group (AA) received intravenous saline (n = 6). Femoral arteriovenous blood samples and muscle biopsies were obtained during a primed (2.0 micromol/kg) constant infusion (0.05 micromol. kg(-1). min(-1)) of l-[ring-(2)H(5)]phenylalanine before and after ingestion of 15 g of EAA. Hypercortisolemia [36.5 +/- 2.1 (C + AA) vs. 9.0 +/- 1.0 microg/dl (AA)] increased postabsorptive arterial, venous, and muscle intracellular phenylalanine concentrations. Hypercortisolemia also increased postabsorptive and post-EAA insulin concentrations. Net protein balance was blunted (40% lower) following EAA ingestion but remained positive for a greater period of time (60 vs. 180 min) in the C + AA group. Thus, although differences in protein metabolism were evident, EAA ingestion improved muscle protein anabolism during acute hypercortisolemia and may help minimize muscle loss following debilitating injury.

  4. Oral essential amino acid supplements in children with advanced chronic renal failure.

    PubMed

    Jones, R W; Dalton, N; Start, K; El-Bishti, M M; Chantler, C

    1980-07-01

    The effects on growth, nitrogen balance, and body composition of a protein-restricted diet supplemented with oral essential amino acids (EAA) were studied in seven children with advanced chronic renal failure. The diet was designed to provide minimum protein requirements for height-age, half in unselected form and half as an EAA supplement. Energy from carbohydrate and fat were increased to give a protein/energy ratio of 1.25 G:100 kcal. Nitrogen balance, studied in five children before and after 6 to 8 months of EAA treatment, was improved in each case. intracellular water (total body water minus bromide space) increased in four children but fell in three children during treatment. No significant improvement in growth, expressed as height or height velocity standard deviation scores in relation to bone age, was observed. Serum urea and urea/creatinine ratio fell after institution of EAA treatment, but the fall was not sustained. Although the EAA preparation proved acceptable to the children, dietary assessments indicated that the desired dietary aims were rarely achieved. It is concluded that, in this pediatric age group, the long-term application of a protein restricted diet with EAA supplements is of limited value.

  5. Tri-peptide reference structures for the calculation of relative solvent accessible surface area in protein amino acid residues.

    PubMed

    Topham, Christopher M; Smith, Jeremy C

    2015-02-01

    Relative amino acid residue solvent accessibility values allow the quantitative comparison of atomic solvent-accessible surface areas in different residue types and physical environments in proteins and in protein structural alignments. Geometry-optimised tri-peptide structures in extended solvent-exposed reference conformations have been obtained for 43 amino acid residue types at a high level of quantum chemical theory. Significant increases in side-chain solvent accessibility, offset by reductions in main-chain atom solvent exposure, were observed for standard residue types in partially geometry-optimised structures when compared to non-minimised models built from identical sets of proper dihedral angles abstracted from the literature. Optimisation of proper dihedral angles led most notably to marked increases of up to 54% in proline main-chain atom solvent accessibility compared to literature values. Similar effects were observed for fully-optimised tri-peptides in implicit solvent. The relief of internal strain energy was associated with systematic variation in N, C(α) and C(β) atom solvent accessibility across all standard residue types. The results underline the importance of optimisation of 'hard' degrees of freedom (bond lengths and valence bond angles) and improper dihedral angle values from force field or other context-independent reference values, and impact on the use of standardised fixed internal co-ordinate geometry in sampling approaches to the determination of absolute values of protein amino acid residue solvent accessibility. Quantum chemical methods provide a useful and accurate alternative to molecular mechanics methods to perform energy minimisation of peptides containing non-standard (chemically modified) amino acid residues frequently present in experimental protein structure data sets, for which force field parameters may not be available. Reference tri-peptide atomic co-ordinate sets including hydrogen atoms are made freely available.

  6. Amino acid residues of bitter taste receptor TAS2R16 that determine sensitivity in primates to β-glycosides

    PubMed Central

    Imai, Hiroo; Suzuki-Hashido, Nami; Ishimaru, Yoshiro; Sakurai, Takanobu; Yin, Lijie; Pan, Wenshi; Ishiguro, Masaji; Masuda, Katsuyoshi; Abe, Keiko; Misaka, Takumi; Hirai, Hirohisa

    2016-01-01

    In mammals, bitter taste is mediated by TAS2Rs, which belong to the family of seven transmembrane G protein-coupled receptors. Since TAS2Rs are directly involved in the interaction between mammals and their dietary sources, it is likely that these genes evolved to reflect species-specific diets during mammalian evolution. Here, we analyzed the amino acids responsible for the difference in sensitivities of TAS2R16s of various primates using a cultured cell expression system. We found that the sensitivity of TAS2R16 varied due to several amino acid residues. Mutation of amino acid residues at E86T, L247M, and V260F in human and langur TAS2R16 for mimicking the macaque TAS2R16 decreased the sensitivity of the receptor in an additive manner, which suggests its contribution to the potency of salicin, possibly via direct interaction. However, mutation of amino acid residues 125 and 133 in human TAS2R16, which are situated in helix 4, to the macaque sequence increased the sensitivity of the receptor. These results suggest the possibility that bitter taste sensitivities evolved independently by replacing specific amino acid residues of TAS2Rs in different primate species to adapt to species-specific food. PMID:27924271

  7. SeqX: a tool to detect, analyze and visualize residue co-locations in protein and nucleic acid structures

    PubMed Central

    Biro, Jan C; Fördös, Gergely

    2005-01-01

    Background The interacting residues of protein and nucleic acid sequences are close to each other – they are co-located. Structure databases (like Protein Data Bank, PDB and Nucleic Acid Data Bank, NDB) contain all information about these co-locations; however it is not an easy task to penetrate this complex information. We developed a JAVA tool, called SeqX for this purpose. Results SeqX tool is useful to detect, analyze and visualize residue co-locations in protein and nucleic acid structures. The user a. selects a structure from PDB; b. chooses an atom that is commonly present in every residues of the nucleic acid and/or protein structure(s) c. defines a distance from these atoms (3–15 Å). The SeqX tool detects every residue that is located within the defined distances from the defined "backbone" atom(s); provides a DotPlot-like visualization (Residues Contact Map), and calculates the frequency of every possible residue pairs (Residue Contact Table) in the observed structure. It is possible to exclude +/- 1 to 10 neighbor residues in the same polymeric chain from detection, which greatly improves the specificity of detections (up to 60% when tested on dsDNA). Results obtained on protein structures showed highly significant correlations with results obtained from literature (p < 0.0001, n = 210, four different subsets). The co-location frequency of physico-chemically compatible amino acids is significantly higher than is calculated and expected in random protein sequences (p < 0.0001, n = 80). Conclusion The tool is simple and easy to use and provides a quick and reliable visualization and analyses of residue co-locations in protein and nucleic acid structures. Availability and requirements SeqX, Java J2SE Runtime Environment 5.0 (available from [see Additional file 1] ) and at least a 1 GHz processor and with a minimum 256 Mb RAM. Source codes are available from the authors. PMID:16011796

  8. Leaching and selective zinc recovery from acidic leachates of zinc metallurgical leach residues.

    PubMed

    Sethurajan, Manivannan; Huguenot, David; Jain, Rohan; Lens, Piet N L; Horn, Heinrich A; Figueiredo, Luiz H A; van Hullebusch, Eric D

    2017-02-15

    Zinc (Zn) leaching yields and kinetics from three different zinc plant leach residues (ZLR) generated in different periods (ZLR1>30 years, ZLR2 5-30 years and ZLR3<2 years) were investigated. The factors affecting the Zn leaching rate such as solid to liquid ratio, temperature, acid concentration and agitation were optimized. Under optimum conditions, 46.2 (±4.3), 23.3 (±2.7) and 17.6 (±1.2) mg of Zn can be extracted per gram of ZLR1, ZLR2 and ZLR3, respectively. The Zn leaching kinetics of ZLRs follow the shrinking core diffusion model. The activation energy required to leach Zn from ZLR1, ZLR2 and ZLR3 were estimated to be 2.24kcal/mol, 6.63kcal/mol and 11.7kcal/mol, respectively, by the Arrhenius equation. The order of the reaction with respect to the sulfuric acid concentration was also determined as 0.20, 0.56, and 0.87 for ZLR1, ZLR2 and ZLR3, respectively. Zn was selectively recovered from the leachates by adjusting the initial pH and by the addition of sodium hydroxide and sodium sulfide. More than 90% of Zn was selectively recovered as sphalerite from the ZLR polymetallic leachates by chemical sulfide precipitation.

  9. Evidence for pentagalloyl glucose binding to human salivary alpha-amylase through aromatic amino acid residues.

    PubMed

    Gyémánt, Gyöngyi; Zajácz, Agnes; Bécsi, Bálint; Ragunath, Chandran; Ramasubbu, Narayanan; Erdodi, Ferenc; Batta, Gyula; Kandra, Lili

    2009-02-01

    We demonstrate here that pentagalloyl glucose (PGG), a main component of gallotannins, was an effective inhibitor of HSA and it exerted similar inhibitory potency to Aleppo tannin used in this study. The inhibition of HSA by PGG was found to be non-competitive and inhibitory constants of K(EI)=2.6 microM and K(ESI)=3.9 microM were determined from Lineweaver-Burk secondary plots. PGG as a model compound for gallotannins was selected to study the inhibitory mechanism and to characterize the interaction of HSA with this type of molecules. Surface plasmon resonance (SPR) binding experiments confirmed the direct interaction of HSA and PGG, and it also established similar binding of Aleppo tannin to HSA. Saturation transfer difference (STD) experiment by NMR clearly demonstrated the aromatic rings of PGG may be involved in the interaction suggesting a possible stacking with the aromatic side chains of HSA. The role of aromatic amino acids of HSA in PGG binding was reinforced by kinetic studies with the W58L and Y151M mutants of HSA: the replacement of the active site aromatic amino acids with aliphatic ones decreased the PGG inhibition dramatically, which justified the importance of these residues in the interaction.

  10. Quantitative assessment of the preferences for the amino acid residues flanking archaeal N-linked glycosylation sites.

    PubMed

    Igura, Mayumi; Kohda, Daisuke

    2011-05-01

    Oligosaccharyltransferase (OST) catalyzes the transfer of an oligosaccharide to an asparagine residue in polypeptide chains. Using positional scanning peptide libraries, we assessed the effects of amino acid variations on the in vitro glycosylation efficiency within and adjacent to an N-glycosylation consensus, Asn-X-Ser/Thr, with an archaeal OST from Pyrococcus furiosus. The amino acid variations at the X(-2), X(-1) and X(+1) positions in the sequence X(-2)-X(-1)-Asn-X-Ser/Thr-X(+1) strongly influenced the glycosylation efficiency to a similar extent at position X. The rank orders of the amino acid preferences were unique at each site. We experimentally confirmed that the archaeal OST does not require an acidic residue at the -2 position, unlike the eubacterial OSTs. Pro was disfavored at the -1 and +1 positions, although the exclusion was not as strict as that at X, whereas Pro was the most favored amino acid residue among those studied at the -2 position. The overall amino acid preferences are correlated with a conformational propensity to extend around the sequon. The results of the library experiments revealed that the optimal acceptor sequence was PYNVTK, with a K(m) of 10 µM. The heat-stable, single-subunit OST of P. furiosus is a potential candidate enzyme for the production of recombinant glycoproteins in bacterial cells. Quantitative assessment of the amino acid preferences of the OST enzyme will facilitate the proper design of a production system.

  11. CS(2) blinds in Brassica crops: false positive results in the dithiocarbamate residue analysis by the acid digestion method.

    PubMed

    Perz, R C; van Lishaut, H; Schwack, W

    2000-03-01

    Various members of the Brassicaceae family (cauliflower, savoy cabbage, red cabbage, turnip-rooted cabbage) grown without any application of pesticides were analyzed according to the acid digestion method commonly used for the determination of dithiocarbamate fungicide residues. Depending on postharvest treatments, high non-anthropogenic CS(2) values up to 4 mg/kg were found in some cases, especially in frozen raw cabbage samples, exceeding maximum residue limits. To explore phytogenic CS(2) occurrences, two model substances (phenylisothiocyanate and methyl tryptaminedithiocarbamate) representing natural mustard oils and brassinines, respectively, were analyzed for their acid hydrolysis decomposition products. In both cases, COS was found generally, but CS(2) was readily formed during acid digestion, too, when sulfides were present. The results obtained clearly demonstrate that CS(2) values determined by using the acid digestion method of crops rich in secondary metabolism sulfur compounds have to be interpreted carefully.

  12. Allelic Analyses of the Arabidopsis YUC1 Locus Reveal Residues and Domains Essential for the Functions of YUC Family of Flavin Monooxygenases

    PubMed Central

    Hou, Xianhui; Liu, Sainan; Pierri, Florencia; Dai, Xinhua; Qu, Li-Jia; Zhao, Yunde

    2011-01-01

    Flavin monooxygenases (FMOs) play critical roles in plant growth and development by synthesizing auxin and other signaling molecules. However, the structure and function relationship within plant FMOs is not understood. Here we defined the important residues and domains of the Arabidopsis YUC1 FMO, a key enzyme in auxin biosynthesis. We previously showed that simultaneous inactivation of YUC1 and its homologue YUC4 caused severe defects in vascular and floral development. We mutagenized the yuc4 mutant and screened for mutants with phenotypes similar to those of yuc1 yuc4 double mutants. Among the isolated mutants, five of them contained mutations in the YUC1 gene. Interestingly, the mutations identified in the new yuc1 alleles were concentrated in the two GXGXXG motifs that are highly conserved among the plant FMOs. One such motif presumably binds to flavin adenine dinucleotide (FAD) cofactor and the other binds to nicotinamide adenine dinucleotide phosphate (NADPH). We also identified the Ser139 to Phe conversion in yuc1, a mutation that is located between the two nucleotide-binding sites. By analyzing a series of yuc1 mutants, we identified key residues and motifs essential for the functions of YUC1 FMO. PMID:21205174

  13. Modular organization of residue-level contacts shape the selection pressure on individual amino acid sites of ribosomal proteins.

    PubMed

    Mallik, Saurav; Kundu, Sudip

    2017-02-22

    Understanding the molecular evolution of macromolecular complexes in the light of their structure, assembly and stability is of central importance. Here we address how the modular organization of native molecular contacts shapes the selection pressure on individual residue sites of ribosomal complexes. The bacterial ribosomal complex is represented as a residue contact network where nodes represent amino acid/nucleotide residues and edges represent their van der Waals interactions. We find statistically overrepresented native amino acid-nucleotide contacts (OaantC, one amino acid contacts one or multiple nucleotides, inter-nucleotide contacts are disregarded). Contact number is defined as the number of nucleotides contacted. Involvement of individual amino acids in OaantCs with smaller contact numbers is more random, while only a few amino acids significantly contribute to OaantCs with higher contact numbers. An investigation of structure, stability and assembly of bacterial ribosome depicts the involvement of these OaantCs in diverse biophysical interactions stabilizing the complex, including high-affinity protein-RNA contacts, inter-protein cooperativity, inter-subunit bridge, packing of multiple ribosomal RNA domains etc. Amino acid-nucleotide constituents of OaantCs with higher contact numbers are generally associated with significantly slower substitution rates compared to that of OaantCs with smaller contact numbers. This evolutionary rate heterogeneity emerges from the strong purifying selection pressure that conserves the respective amino acid physicochemical properties relevant to the stabilizing interaction with OaantC nucleotides. An analysis of relative molecular orientations of OaantC residues and their interaction energetics provides the biophysical ground of purifying selection conserving OaantC amino acid physicochemical properties.

  14. Leucine-enriched essential amino acid supplementation during moderate steady state exercise enhances postexercise muscle protein synthesis

    Technology Transfer Automated Retrieval System (TEKTRAN)

    BACKGROUND: The effects of essential amino acid (EAA) supplementation during moderate steady state (ie, endurance) exercise on postexercise skeletal muscle metabolism are not well described, and the potential role of supplemental leucine on muscle protein synthesis (MPS) and associated molecular re...

  15. Combined application of origanum vulgare l. essential oil and acetic acid for controlling the growth of staphylococcus aureus in foods

    PubMed Central

    de Souza, Evandro Leite; de Barros, Jefferson Carneiro; da Conceição, Maria Lúcia; Neto, Nelson Justino Gomes; da Costa, Ana Caroliny Vieira

    2009-01-01

    This study evaluated the occurrence of an enhancing inhibitory effect of the combined application of Origanum vulgare L. essential oil and acetic acid against Staphylococcus aureus by the determination of Fractional Inhibitory Concentration (FIC) index and kill-time assay in nutrient broth, meat broth and in a food model (meat pieces). Acetic acid showed MIC and MFC of 0.6 and 1.25 μL.mL-1, respectively. For O. vulgare essential oil MIC and MBC were 1.25 and 2.5 μL.mL-1, respectively. FIC indexes of the mixture of essential oil and acetic acid at MIC x ½ were ≤ 1.0, showing an additive effect. No synergy was found at kill-time study. Anti-staphylococcal effect of the antimicrobials alone or in mixture (MIC x ½) was lower in meat than in nutrient and meat broths. The effective combination of essential oils and organic acids could appear as an attractive alternative for the food industry, as the doses to inhibit the microbial growth in foods can be lowered. PMID:24031377

  16. Leucine-enriched essential amino acids attenuate inflammation in rat muscle and enhance muscle repair after eccentric contraction.

    PubMed

    Kato, Hiroyuki; Miura, Kyoko; Nakano, Sayako; Suzuki, Katsuya; Bannai, Makoto; Inoue, Yoshiko

    2016-09-01

    Eccentric exercise results in prolonged muscle damage that may lead to muscle dysfunction. Although inflammation is essential to recover from muscle damage, excessive inflammation may also induce secondary damage, and should thus be suppressed. In this study, we investigated the effect of leucine-enriched essential amino acids on muscle inflammation and recovery after eccentric contraction. These amino acids are known to stimulate muscle protein synthesis via mammalian target of rapamycin (mTOR), which, is also considered to alleviate inflammation. Five sets of 10 eccentric contractions were induced by electrical stimulation in the tibialis anterior muscle of male SpragueDawley rats (8-9 weeks old) under anesthesia. Animals received a 1 g/kg dose of a mixture containing 40 % leucine and 60 % other essential amino acids or distilled water once a day throughout the experiment. Muscle dysfunction was assessed based on isometric dorsiflexion torque, while inflammation was evaluated by histochemistry. Gene expression of inflammatory cytokines and myogenic regulatory factors was also measured. We found that leucine-enriched essential amino acids restored full muscle function within 14 days, at which point rats treated with distilled water had not fully recovered. Indeed, muscle function was stronger 3 days after eccentric contraction in rats treated with amino acids than in those treated with distilled water. The amino acid mix also alleviated expression of interleukin-6 and impeded infiltration of inflammatory cells into muscle, but did not suppress expression of myogenic regulatory factors. These results suggest that leucine-enriched amino acids accelerate recovery from muscle damage by preventing excessive inflammation.

  17. Heavily fractionated noble gases in an acid residue from the Klein Glacier 98300 EH3 chondrite

    NASA Astrophysics Data System (ADS)

    Nakashima, Daisuke; Ott, Ulrich; El Goresy, Ahmed; Nakamura, Tomoki

    2010-09-01

    Noble gases were measured both in bulk samples (stepped pyrolysis and total extraction) and in a HF/HCl residue (stepped pyrolysis and combustion) from the Klein Glacier (KLE) 98300 EH3 chondrite. Like the bulk meteorite and as seen in previous studies of bulk type 3 E chondrites ("sub-Q"), the acid residue contains elementally fractionated primordial noble gases. As we show here, isotopically these are like those in phase-Q of primitive meteorites, but elementally they are heavily fractionated relative to these. The observed noble gases are different from "normal" Q noble gases also with respect to release patterns, which are similar to those of Ar-rich noble gases in anhydrous carbonaceous chondrites and unequilibrated ordinary chondrites (with also similar isotopic compositions). While we cannot completely rule out a role for parent body processes such as thermal and shock metamorphism (including a later thermal event) in creating the fractionated elemental compositions, parent body processes in general seem not be able to account for the distinct release patterns from those of normal Q noble gases. The fractionated gases may have originated from ion implantation from a nebular plasma as has been suggested for other types of primordial noble gases, including Q, Ar-rich, and ureilite noble gases. With solar starting composition, the corresponding effective electron temperature is about 5000 K. This is lower than inferred for other primordial noble gases (10,000-6000 K). Thus, if ion implantation from a solar composition reservoir was a common process for the acquisition of primordial gas, electron temperatures in the early solar system must have varied spatially or temporally between 10,000 and 5000 K. Neon and xenon isotopic ratios of the residue suggest the presence of presolar silicon carbide and diamond in abundances lower than in the Qingzhen EH3 and Indarch EH4 chondrites. Parent body processes including thermal and shock metamorphism and a late thermal

  18. Effect of ferrous sulfate and nitrohumic acid neutralization on the leaching of metals from a combined bauxite residue.

    PubMed

    Ren, Jie; Liu, Jidong; Chen, Juan; Liu, Xiaolian; Li, Fasheng; Du, Ping

    2017-02-23

    Bauxite residue neutralization is intended to open opportunities for revegetation and reuse of the residue. Ferrous sulfate (FS) and nitrohumic acid (NA) were two kinds of materials studied for pH reduction of the residue from 10.6 to 8.3 and 8.1, respectively. The effects of FS and NA on the leaching of metals from a combined bauxite residue were investigated by using sequential and multiple extraction procedures. Neutralization with FS and NA restricted the leaching of Al, V, and Pb from the residue but promoted the leaching of Fe, Cu, Mn, and Ni, consistent with the changes in the potentially mobile fractions. With the exceptions of Pb and Ni, leaching of metals increased during a 10-day extraction period. However, the maximum leaching of Al, V, Pb, Fe, Cu, Mn, and Ni from neutralized bauxite residue were 0.46 mg/L, 59.3, 12.9, 167, 95.3, 15.5, and 14.5 μg/L, respectively, which were under the corresponding limits in the National Standard (GB/T 14848-93). Although it is necessary to consider the continued leaching of metals during neutralization, both maximum and accumulation leaching concentrations of metals from a combined bauxite residue were too low to pose a potential environmental risk.

  19. Removal of acidic residues of the prodomain of PCSK9 increases its activity towards the LDL receptor.

    PubMed

    Holla, Øystein L; Laerdahl, Jon K; Strøm, Thea Bismo; Tveten, Kristian; Cameron, Jamie; Berge, Knut Erik; Leren, Trond P

    2011-03-11

    Proprotein convertase subtilisin/kexin type 9 (PCSK9) binds to the low density lipoprotein receptor (LDLR) at the cell surface and mediates intracellular degradation of the LDLR. The amino-terminus of mature PCSK9, residues 31-53 of the prodomain, has an inhibitory effect on this function of PCSK9, but the underlying mechanism is not fully understood. In this study, we have identified two highly conserved negatively charged segments (residues 32-40 and 48-50, respectively) within this part of the prodomain and performed deletions and substitutions to study their importance for degradation of the LDLRs. Deletion of the acidic residues of the longest negatively charged segment increased PCSK9's ability to degrade the LDLR by 31%, whereas a modest 8% increase was observed when these residues were mutated to uncharged amino acids. Thus, both the length and the charge of this part of the prodomain were important for its inhibitory effect. Deletion of the residues of the shorter second negatively charged segment only increased PCSK9's activity by 8%. Substitution of the amino acids of both charged segments to uncharged residues increased PCSK9's activity by 36%. These findings indicate that the inhibitory effect of residues 31-53 of the prodomain is due to the negative charge of this segment. The underlying mechanism could involve the binding of this peptide segment to positively charged structures which are important for PCSK9's activity. One possible candidate could be the histidine-rich C-terminal domain of PCSK9.

  20. [Recent biochemical nutrition knowledge in relation to metabolism and the significance of essential fatty acids and n-3-fatty acids contained in fish].

    PubMed

    Kolb, E

    1989-10-01

    A survey is given on some newer knowledge about metabolism and about the importance of the essential fatty acids and of the n-3 fatty acids (eicosapentaenic, docosapentaenic, docosahexaenic acids) which occur in fish oils. In the body the linoleic acid via intermediate steps can be transformed into the arachidonic acid, from which various prostaglandins and leucotriens as well as the thromboxane A2 can be formed. The transformation of the linolenic acid into the eicosapentaenic acid is slight in man. The docosahexaenic acid is necessary for the construction of phospholipids in the brain and in the retina. The uptake of fish fatty acids inhibits the formation of thromboxane A2 and of leukotriens from the arachidonic acid. The fish fatty acids further in the liver in the peroxisomas the activity of the enzymes for the beta-oxidation; the formation of lipoproteins of high density increases under their influence: the triacylglyceride content, the cholesterol as well as the lipoprotein content of very low and low density decreases, when there is an adequate part of fish fatty acids in the nutrition.

  1. Effect of second coagulant addition on coagulation efficiency, floc properties and residual Al for humic acid treatment by Al13 polymer and polyaluminum chloride (PACl).

    PubMed

    Xu, Weiying; Gao, Baoyu; Wang, Yan; Yue, Qinyan; Ren, Haijing

    2012-05-15

    Influence of second dose on coagulation efficiency, floc re-growth, fractal structure and residual Al of the effluent in humic acid (HA) coagulation with Al(13) polymer ([Al(13)O(4)(OH)(24)(H(2)O)(12)](7+)) and PACl were comparatively investigated in this study. Effects of breakage shear on the floc properties generated in the coagulation with and without additional dose were also investigated. The results indicated that additional dose during breakage could essentially improve the HA removal efficiency and floc re-growth in both Al(13) and PACl coagulations. Second doses of Al(13) at 0.5 and 1.0mg/L resulted in better turbidity and UV(254) removal as well as floc re-growth rather than higher additional dose of 1.5 and 2.0mg/L; while in PACl coagulation, more efficient HA removal and better floc re-growth were obtained at higher additional doses (1.0, 1.5 and 2.0mg/L). Small additional Al(13) could apparently increase the D(f) of re-formed flocs while the additional PACl displayed inconspicuous effect on floc D(f). The additional coagulant dose could alleviate the further decrease of re-grown floc size with increased breakage shear for both coagulants. The residual Al analysis implied that two-stage addition contributed to lower residual Al in effluent than one-time addition mode with the same total coagulant concentration.

  2. Retinoic Acid Signaling Is Essential for Valvulogenesis by Affecting Endocardial Cushions Formation in Zebrafish Embryos.

    PubMed

    Li, Junbo; Yue, Yunyun; Zhao, Qingshun

    2016-02-01

    Retinoic acid (RA) plays important roles in many stages of heart morphogenesis. Zebrafish embryos treated with exogenous RA display defective atrio-ventricular canal (AVC) specification. However, whether endogenous RA signaling takes part in cardiac valve formation remains unknown. Herein, we investigated the role of RA signaling in cardiac valve development by knocking down aldh1a2, the gene encoding an enzyme that is mainly responsible for RA synthesis during early development, in zebrafish embryos. The results showed that partially knocking down aldh1a2 caused defective formation of primitive cardiac valve leaflets at 108 hpf (hour post-fertilization). Inhibiting endogenous RA signaling by 4-diethylaminobenzal-dehyde revealed that 16-26 hpf was a key time window when RA signaling affects the valvulogenesis. The aldh1a2 morphants had defective formation of endocardial cushion (EC) at 76 hpf though they had almost normal hemodynamics and cardiac chamber specification at early development. Examining the expression patterns of AVC marker genes including bmp4, bmp2b, nppa, notch1b, and has2, we found the morphants displayed abnormal development of endocardial AVC but almost normal development of myocardial AVC at 50 hpf. Being consistent with the reduced expression of notch1b in endocardial AVC, the VE-cadherin gene cdh5, the downstream gene of Notch signaling, was ectopically expressed in AVC of aldh1a2 morphants at 50 hpf, and overexpression of cdh5 greatly affected the formation of EC in the embryos at 76 hpf. Taken together, our results suggest that RA signaling plays essential roles in zebrafish cardiac valvulogenesis.

  3. Tracing the biosynthetic source of essential amino acids in marine turtles using delta13C fingerprints.

    PubMed

    Arthur, Karen E; Kelez, Shaleyla; Larsen, Thomas; Choy, C Anela; Popp, Brian N

    2014-05-01

    Plants, bacteria, and fungi produce essential amino acids (EAAs) with distinctive patterns of delta13C values that can be used as naturally occurring fingerprints of biosynthetic origin of EAAs in a food web. Because animals cannot synthesize EAAs and must obtain them from food, their tissues reflect delta13C(EAA) patterns found in diet, but it is not known how microbes responsible for hindgut fermentation in some herbivores influence the delta13C values of EAAs in their hosts' tissues. We examined whether distinctive delta13C fingerprints of hindgut flora are evident in the tissues of green turtles (Chelonia mydas), which are known to be facultative hindgut fermenters. We determined delta13C(EAA) values in tissues of green turtles foraging herbivorously in neritic habitats of Hawaii and compared them with those from green, olive ridley, and loggerhead turtles foraging carnivorously in oceanic environments of the central and southeast Pacific Ocean. Results of multivariate statistical analysis revealed two distinct groups that could be distinguished based on unique delta13C(EAA) patterns. A three-end-member predictive linear discriminant model indicated that delta13C(EAA) fingerprints existed in the tissues of carnivorous turtles that resembled patterns found in microalgae, which form the base of an oceanic food web, whereas herbivorous turtles derive EAAs from a bacterial or seagrass source. This study demonstrates the capacity for delta13C fingerprinting to establish the biosynthetic origin of EAAs in higher consumers, and that marine turtles foraging on macroalgal diets appear to receive nutritional supplementation from bacterial symbionts in their digestive system.

  4. Dose-escalation study of octanoic acid in patients with essential tremor

    PubMed Central

    Voller, Bernhard; Lines, Emily; McCrossin, Gayle; Tinaz, Sule; Lungu, Codrin; Grimes, George; Starling, Judith; Potti, Gopal; Haubenberger, Dietrich

    2016-01-01

    BACKGROUND. Recently, 1-octanol has been shown to have efficacy in treating patients with essential tremor (ET). The primary metabolite of 1-octanol is octanoic acid (OA), which is now thought to be the active substance that mediates tremor suppression. Our aim was to describe the maximum tolerated dose (MTD) of oral OA in patients with ET and assess the pharmacokinetics (PK) and pharmacodynamics (PD) profile of OA. METHODS. The MTD was studied using an open-label, single-ascending 3 + 3 dose–escalation design. Predefined single doses ranged from 8 to 128 mg/kg, with grade 2 adverse events (AEs) defined as dose-limiting toxicity. Tremor was assessed using accelerometry, digital spiral analysis, and a standard clinical rating scale at baseline and up to 600 minutes after intake. Safety assessments and PK sampling were also performed. RESULTS. Dose-limiting toxicity was not reached. The most frequent AE was mild abdominal discomfort. Exposure (AUC) increased linearly with the dose. Secondary efficacy measures suggested a dose-dependent reduction of tremor. Accordingly, a single unified PK/PD model with an effect compartment and sigmoid maximum effect (Emax) response could be built that accounted well for the time profiles of plasma concentrations as well as effects on tremor severity across the 5 dose levels. CONCLUSION. Although our trial did not reach an MTD, a dose-dependent effect was demonstrated in the PK/PD model as well as in secondary efficacy outcomes. Future studies are needed to explore the safety in higher dose ranges and to confirm dose-dependent efficacy in a placebo-controlled design. TRIAL REGISTRATION. Clinicaltrials.gov NCT01468948 FUNDING. NINDS Intramural Research Program; TG Therapeutics Inc. PMID:26927672

  5. Spatial Patterns and Temperature Predictions of Tuna Fatty Acids: Tracing Essential Nutrients and Changes in Primary Producers.

    PubMed

    Pethybridge, Heidi R; Parrish, Christopher C; Morrongiello, John; Young, Jock W; Farley, Jessica H; Gunasekera, Rasanthi M; Nichols, Peter D

    2015-01-01

    Fatty acids are among the least understood nutrients in marine environments, despite their profile as key energy components of food webs and that they are essential to all life forms. Presented here is a novel approach to predict the spatial-temporal distributions of fatty acids in marine resources using generalized additive mixed models. Fatty acid tracers (FAT) of key primary producers, nutritional condition indices and concentrations of two essential long-chain (≥C20) omega-3 fatty acids (EFA) measured in muscle of albacore tuna, Thunnus alalunga, sampled in the south-west Pacific Ocean were response variables. Predictive variables were: location, time, sea surface temperature (SST) and chlorophyll-a (Chla), and phytoplankton biomass at time of catch and curved fork length. The best model fit for all fatty acid parameters included fish length and SST. The first oceanographic contour maps of EFA and FAT (FATscapes) were produced and demonstrated clear geographical gradients in the study region. Predicted changes in all fatty acid parameters reflected shifts in the size-structure of dominant primary producers. Model projections show that the supply and availability of EFA are likely to be negatively affected by increases in SST especially in temperate waters where a 12% reduction in both total fatty acid content and EFA proportions are predicted. Such changes will have large implications for the availability of energy and associated health benefits to high-order consumers. Results convey new concerns on impacts of projected climate change on fish-derived EFA in marine systems.

  6. Reclamation of acidic mine residues by creation of technosoils with the addition of biochar and marble waste

    NASA Astrophysics Data System (ADS)

    Moreno-Barriga, Fabián; Díaz, Vicente; Acosta, José; Faz, Ángel; Zornoza, Raul

    2016-04-01

    This study reports the short-term effect of biochar and marble waste addition for the reclamation of acidic mine residues. A lab incubation was carried out for 90 days. Biochars derived from pig manure (PM), crop residues (CR) and municipal solid waste (MSW) were added to the soil at a rate of 20 g kg-1. The marble waste (MW) was added at a rate of 200 g kg-1. Bochars and MW were applied independently and combined. A control soil was used without application of amendments. The evolution of different physical, chemical and biochemical properties and availability of heavy metals was periodically monitored. Results showed that original pH (2.8) was increased with all amendments, those samples containing MW being the ones with the highest pH (~8.0). The electrical conductivity (EC) decreased from 6.6 to 3.0-4.5 mS cm-1 in all the treatments receiving MW. Soil organic C (SOC) increased in all samples receiving biochar up to 18-20 g kg-1, with no shifts during the 90 d incubation, indicating the high stability of the C supplied. Recalcitrant organic C accounted for ~90-98% of the SOC. No significant effect of amendment addition was observed for carbohydrates, soluble C, microbial biomass C and β-glucosidase activity. However, arylesterase activity increased with amendments, highly related to pH. The availability of heavy metals decreased up to 90-95% owing to the addition of amendments, mainly in samples containing MW. The MW provided conditions to increase pH and decrease EC and metals mobility. Biochar was an effective strategy to increase SOC, recalcitrant C and AS, essential to create soil structure. However, a labile source of organic matter should be added together with the proposed amendments to promote the activation of microbial communities. Acknowledgement : This work has been funded by Fundación Séneca (Agency of Science and Technology of the Region of Murcia, Spain) by the project 18920/JLI/13

  7. Studies on essential fatty acid deficiency. Effect of the deficiency on the lipids in liver mitochondria and oxidative phosphorylation

    PubMed Central

    Biran, L. A.; Bartley, W.; Carter, C. W.; Renshaw, A.

    1965-01-01

    1. Dietary deficiency of essential fatty acids results in a twofold increase in the neutral lipid content of liver mitochondria as compared with the corresponding value for stock-fed rats. 2. Deficiency produces changes in the pattern of the constituent fatty acids of the main phospholipid fractions of liver mitochondria which are similar to those previously reported for the lipids of whole liver. There is a fall in the content of C18:2 acid and to a smaller extent of C20:4 acid associated with a rise of C16:1, C18:1 and C20:3 acids. 3. Deficiency results in small decreases in the phosphorylation quotients of liver mitochondria during oxidation of succinate and pyruvate, but the values lie within the range reported for normal mitochondria. Mitochondrial respiration with succinate is decreased as a result of deficiency but no change was observed with pyruvate as substrate. PMID:14342237

  8. Structure-function analysis of MurJ reveals a solvent-exposed cavity containing residues essential for peptidoglycan biogenesis in Escherichia coli.

    PubMed

    Butler, Emily K; Davis, Rebecca M; Bari, Vase; Nicholson, Paul A; Ruiz, Natividad

    2013-10-01

    Gram-negative bacteria such as Escherichia coli build a peptidoglycan (PG) cell wall in their periplasm using the precursor known as lipid II. Lipid II is a large amphipathic molecule composed of undecaprenyl diphosphate and a disaccharide-pentapeptide that PG-synthesizing enzymes use to build the PG sacculus. During PG biosynthesis, lipid II is synthesized at the cytoplasmic face of the inner membrane and then flipped across the membrane. This translocation of lipid II must be assisted by flippases thought to shield the disaccharide-pentapeptide as it crosses the hydrophobic core of the membrane. The inner membrane protein MurJ is essential for PG biogenesis and homologous to known and putative flippases of the MOP (multidrug/oligo-saccharidyl-lipid/polysaccharide) exporter superfamily, which includes flippases that translocate undecaprenyl diphosphate-linked oligosaccharides across the cytoplasmic membranes of bacteria. Consequently, MurJ has been proposed to function as the lipid II flippase in E. coli. Here, we present a three-dimensional structural model of MurJ generated by the I-TASSER server that suggests that MurJ contains a solvent-exposed cavity within the plane of the membrane. Using in vivo topological studies, we demonstrate that MurJ has 14 transmembrane domains and validate features of the MurJ structural model, including the presence of a solvent-exposed cavity within its transmembrane region. Furthermore, we present functional studies demonstrating that specific charged residues localized in the central cavity are essential for function. Together, our studies support the structural homology of MurJ to MOP exporter proteins, suggesting that MurJ might function as an essential transporter in PG biosynthesis.

  9. GRP1 PH Domain, Like AKT1 PH Domain, Possesses a Sentry Glutamate Residue Essential for Specific Targeting to Plasma Membrane PI(3,4,5)P3

    PubMed Central

    Pilling, Carissa; Landgraf, Kyle E.; Falke, Joseph J.

    2011-01-01

    During the appearance of the signaling lipid PI(3,4,5)P3, an important subset of pleckstrin homology (PH) domains target signaling proteins to the plasma membrane. To ensure proper pathway regulation, such PI(3,4,5)P3-specific PH domains must exclude the more prevalant, constitutive plasma membrane lipid PI(4,5)P2 and bind the rare PI(3,4,5)P3 target lipid with sufficiently high affinity. Our previous study of the E17K mutant of protein kinase B (AKT1) PH domain, together with evidence from Carpten et al (1), revealed that the native AKT1 E17 residue serves as a sentry glutamate that excludes PI(4,5)P2, thereby playing an essential role in specific PI(3,4,5)P3 targeting (2). The sentry glutamate hypothesis proposes that an analogous sentry glutamate residue is a widespread feature of PI(3,4,5)P3-specific PH domains, and that charge reversal mutation at the sentry glutamate position will yield both increased PI(4,5)P2 affinity and constitutive plasma membrane targeting. To test this hypothesis the present study investigates the E345 residue, a putative sentry glutamate, of General Receptor for Phosphoinositides 1 (GRP1) PH domain. The results show that incorporation of the E345K charge reversal mutation into GRP1 PH domain enhances PI(4,5)P2 affinity 8-fold and yields constitutive plasma membrane targeting in cells, reminiscent of the effects of the E17K mutation in AKT1 PH domain. Hydrolysis of plasma membrane PI(4,5)P2 releases E345K GRP1 PH domain into the cytoplasm and the efficiency of this release increases when target Arf6 binding is disrupted. Overall, the findings provide strong support for the sentry glutamate hypothesis and suggest that the GRP1 E345K mutation will be linked to changes in cell physiology and human pathologies, as demonstrated for AKT1 E17K (1, 3). Analysis of available PH domain structures suggests that a lone glutamate residue (or, in some cases an aspartate) is a common, perhaps ubiquitous, feature of PI(3,4,5)P3-specific binding

  10. Essential Amino Acids in the Gluten-Free Diet and Serum in Relation to Depression in Patients with Celiac Disease

    PubMed Central

    van Hees, Nathalie J. M.; Giltay, Erik J.; Tielemans, Susanne M. A. J.; Geleijnse, Johanna M.; Puvill, Thomas; Janssen, Nadine; van der Does, Willem

    2015-01-01

    Introduction Celiac disease (CD) is associated with an increased risk of major depressive disorder, possibly due to deficiencies in micronutrients in the gluten-free diet. We aimed to investigate whether essential amino acids (i.e., the precursors of serotonin, dopamine and other neurotransmitters) are depleted in the diet and serum of CD patients with major depressive disorder. Methods In a cross-sectional study we assessed dietary intake of amino acids and serum levels of amino acids, in 77 CD patients on a gluten-free diet and in 33 healthy controls. Major depressive disorder was assessed with structured interviews (using the Mini International Neuropsychiatric Interview Plus). Dietary intake was assessed using a 203-item food frequency questionnaire. Results Participants had a mean age of 55 years and 74% were women. The intake of vegetable protein was significantly lower in CD patients than in healthy controls (mean difference of 7.8 g/d; 95% CI: 4.7–10.8), as were serum concentrations of tyrosine, phenylalanine and tryptophan (all p < 0.005). However, within the CD patient group, the presence of major depressive disorder (n = 42) was not associated with intake or serum levels of essential amino acids. Conclusions Patients with CD on a long-term gluten-free diet, with good adherence, consume significantly less vegetable protein than controls, and their serum levels of several essential amino acids were also lower. Despite its potential adverse effect, intake and serum levels of essential amino acids were not related to major depression. PMID:25884227

  11. Effect of low molecular weight organic acids on phosphorus adsorption by ferric-alum water treatment residuals.

    PubMed

    Wang, Changhui; Wang, Ziyuan; Lin, Lu; Tian, Binghui; Pei, Yuansheng

    2012-02-15

    Effects of low molecular weight organic acids (LMWOAs; citric acid, oxalic acid and tartaric acid) on phosphorus (P) adsorption by ferric-alum water treatment residuals (FARs) were studied. Both batch and column experiments indicated that the effects of LMWOAs on P adsorption were closely related to adsorption time. Initially, all acids presented inhibitory function on P adsorption. The inhibition became weaker with time, eventually promoting P adsorption for citric acid and tartaric acid. In the column experiment with a 61-day duration, high P adsorption rates (>55%) were observed for the test groups containing citric acid and tartaric acid. Interestingly, higher pH likely enhanced P adsorption with the effects of LMWOAs and a distinct relationship between LMWOAs' effects on P adsorption and their concentrations was not observed. Moreover, fractionation of the adsorbed P from the FARs demonstrated that oxalic acid reduced P adsorption capacity, while citric acid and tartaric acid increased. Based on the forms of Fe and Al existing in the FARs and Fourier transform infrared spectroscopy analyses, LMWOAs can promote P adsorption through activating crystalline Fe/Al and preventing crystallization of amorphous Fe/Al to increase P adsorption sites, and can also inhibit P adsorption by competition with adsorption sites.

  12. Identification of genes and pathways involved in the synthesis of Mead acid (20:3n-9), an indicator of essential fatty acid deficiency.

    PubMed

    Ichi, Ikuyo; Kono, Nozomu; Arita, Yuka; Haga, Shizuka; Arisawa, Kotoko; Yamano, Misato; Nagase, Mana; Fujiwara, Yoko; Arai, Hiroyuki

    2014-01-01

    In mammals, 5,8,11-eicosatrienoic acid (Mead acid, 20:3n-9) is synthesized from oleic acid during a state of essential fatty acid deficiency (EFAD). Mead acid is thought to be produced by the same enzymes that synthesize arachidonic acid and eicosapentaenoic acid, but the genes and the pathways involved in the conversion of oleic acid to Mead acid have not been fully elucidated. The levels of polyunsaturated fatty acids in cultured cells are generally very low compared to those in mammalian tissues. In this study, we found that cultured cells, such as NIH3T3 and Hepa1-6 cells, have significant levels of Mead acid, indicating that cells in culture are in an EFAD state under normal culture conditions. We then examined the effect of siRNA-mediated knockdown of fatty acid desaturases and elongases on the level of Mead acid, and found that knockdown of Elovl5, Fads1, or Fads2 decreased the level of Mead acid. This and the measured levels of possible intermediate products for the synthesis of Mead acid such as 18:2n-9, 20:1n-9 and 20:2n-9 in the knocked down cells indicate two pathways for the synthesis of Mead acid: pathway 1) 18:1n-9→(Fads2)→18:2n-9→(Elovl5)→20:2n-9→(Fads1)→20:3n-9 and pathway 2) 18:1n-9→(Elovl5)→20:1n-9→(Fads2)→20:2n-9→(Fads1)→20:3n-9.

  13. Growth responses of breast and leg muscles to essential amino acids in broiler chicks.

    PubMed

    Mehri, M; Bagherzadeh-Kasmani, F; Rokouei, M

    2016-03-01

    The first three essential amino acids (EAA) for broilers including methionine (Met), lysine (Lys) and threonine (Thr) may greatly influence the growth of chick muscles at early stages of life. In order to survey the potential effects of those EAA on growth muscles, a rotatable three-variable central composite design (CCD) was conducted to track the interrelationships of dietary digestible Met (dMet), Lys (dLys) and Thr (dThr) for optimization of processing yields in broiler chicks using response surface methodology. A total of 60 floor pens of six birds each were assigned to 15 dietary treatments based on CCD containing five levels of dMet (0.416% to 0.584% of diet), dLys (0.881% to 1.319% of diet) and dThr (0.532% to 0.868% of diet) from 3 to 16 days of age. Experimental treatments significantly affected breast mass (BM) and leg mass (LM) of the birds (P<0.05) in which the main effect of dLys on BM was threefold higher than the main effect of dThr, and interaction effect between dMet and dLys was observed on BM (P<0.05). However, in the case of LM, the main effect of dThr was higher than the main effects of dMet and dLys and highest interaction effect exist between dThr and dMet (P<0.05). The second-order models for BM and LM were fitted by least squares regression. Canonical analysis revealed that the stationary points for carcass components were saddle points, thus ridge analysis was performed for getting optimal values of each EAA. Ridge analyses of BM and LM models showed that the maximum BM point may be obtained with 0.58%, 1.05% and 0.76% of dMet, dLys and dThr, respectively, in diet, and maximum LM point may be achieved with 0.58%, 1.09% and 0.70% of dMet, dLys and dThr, respectively, in diet. The resultant ideal ratios of dMet and dThr to dLys were 55% and 72% for BM; 53% and 64% for LM. Moreover, sensitivity analysis showed that the most important amino acids in BM and LM models were Lys and Thr, respectively. In conclusion, providing these three amino

  14. D-amino acid residue in a defensin-like peptide from platypus venom: effect on structure and chromatographic properties.

    PubMed

    Torres, Allan M; Tsampazi, Chryssanthi; Geraghty, Dominic P; Bansal, Paramjit S; Alewood, Paul F; Kuchel, Philip W

    2005-10-15

    The recent discovery that the natriuretic peptide OvCNPb (Ornithorhynchus venom C-type natriuretic peptide B) from platypus (Ornithorynchus anatinus) venom contains a D-amino acid residue suggested that other D-amino-acid-containing peptides might be present in the venom. In the present study, we show that DLP-2 (defensin-like peptide-2), a 42-amino-acid residue polypeptide in the platypus venom, also contains a D-amino acid residue, D-methionine, at position 2, while DLP-4, which has an identical amino acid sequence, has all amino acids in the L-form. These findings were supported further by the detection of isomerase activity in the platypus gland venom extract that converts DLP-4 into DLP-2. In the light of this new information, the tertiary structure of DLP-2 was recalculated using a new structural template with D-Met2. The structure of DLP-4 was also determined in order to evaluate the effect of a D-amino acid at position 2 on the structure and possibly to explain the large retention time difference observed for the two molecules in reverse-phase HPLC. The solution structures of the DLP-2 and DLP-4 are very similar to each other and to the earlier reported structure of DLP-2, which assumed that all amino acids were in the L-form. Our results suggest that the incorporation of the D-amino acid at position 2 has minimal effect on the overall fold in solution.

  15. SucStruct: Prediction of succinylated lysine residues by using structural properties of amino acids.

    PubMed

    López, Yosvany; Dehzangi, Abdollah; Lal, Sunil Pranit; Taherzadeh, Ghazaleh; Michaelson, Jacob; Sattar, Abdul; Tsunoda, Tatsuhiko; Sharma, Alok

    2017-03-28

    Post-Translational Modification (PTM) is a biological reaction which contributes to diversify the proteome. Despite many modifications with important roles in the cellular activity, lysine succinylation has recently emerged as an important PTM mark. It alters the chemical structure of lysines, leading to remarkable changes in the structure and function of proteins. Given the huge amount of proteins being sequenced in the post-genome era, the experimental detection of succinylated residues remains expensive, inefficient and time-consuming. Therefore, the development of computational tools for accurately predicting succinylated lysines is an urgent necessity. To date, several approaches have been proposed but their sensitivity has been reportedly poor. In this paper, we propose an approach that utilizes structural features of amino acids to improve lysine succinylation prediction. Succinylated and non-succinylated lysines were first retrieved from 670 proteins and characteristics such as accessible surface area, backbone torsion angles, and local structure conformations were incorporated. We used the k-nearest neighbors cleaning for dealing with class imbalance and designed a pruned decision tree for classification. Our predictor, referred as SucStruct (Succinylation using Structural features), proved to significantly improve performance when compared to previous predictors, with sensitivity, accuracy and Mathew's correlation coefficient equal to 0.7334-0.7946, 0.7444-0.7608 and 0.4884-0.5240, respectively.

  16. Peptide bond formation does not involve acid-base catalysis by ribosomal residues.

    PubMed

    Bieling, Peter; Beringer, Malte; Adio, Sarah; Rodnina, Marina V

    2006-05-01

    Ribosomes catalyze the formation of peptide bonds between aminoacyl esters of transfer RNAs within a catalytic center composed of ribosomal RNA only. Here we show that the reaction of P-site formylmethionine (fMet)-tRNA(fMet) with a modified A-site tRNA substrate, Phelac-tRNA(Phe), in which the nucleophilic amino group is replaced with a hydroxyl group, does not show the pH dependence observed with small substrate analogs such as puromycin and hydroxypuromycin. This indicates that acid-base catalysis by ribosomal residues is not important in the reaction with the full-size substrate. Rather, the ribosome catalyzes peptide bond formation by positioning the tRNAs, or their 3' termini, through interactions with rRNA that induce and/or stabilize a pH-insensitive conformation of the active site and provide a preorganized environment facilitating the reaction. The rate of peptide bond formation with unmodified Phe-tRNA(Phe) is estimated to be >300 s(-1).

  17. Biosorption of heavy metal ions onto agricultural residues buckwheat hulls functionalized with 1-hydroxylethylidenediphosphonic acid.

    PubMed

    Yin, Ping; Wang, Zengdi; Qu, Rongjun; Liu, Xiguang; Zhang, Jiang; Xu, Qiang

    2012-11-28

    Novel biosorbent materials obtained from agricultural residues buckwheat hulls (BH) were successfully developed through functionalization with 1-hydroxylethylidenediphosphonic acid (HEDP), and they were characterized. This paper reports the feasibility of using HEDP-BH for removal of heavy metals from stimulated wastewater, the experimental results revealed that the adsorption property of functionalized buckwheat hulls with 120 mesh 120-HEDP-BH for Au(III) was very excellent, and the monolayer maximum adsorption capacity for Au(III) calculated from the Langmuir isotherm models was up to 450.45 mg/g at 35 °C. The combined effect of initial solution pH, 120-HEDP-BH dosage, and initial Au(III) concentration was investigated using response surface methodology (RSM), and the result showed that biomass dosage exerted a stronger influence on Au(III) uptake than those of initial pH and initial Au(III) concentration. Analysis of variance (ANOVA) of the quadratic model demonstrated that the model was highly significant. Moreover, investigation on the adsorption selectivity showed that 120-HEDP-BH displayed strong affinity for gold in aqueous solutions and even exhibited 100% selectivity for Au(III) ions in the presence of Zn(II) and Co(II). Regeneration capacities of 120-HEDP-BH were studied using the eluent solutions of 0.0-5.0% thiourea in 0.1 mmol/L HCl, and it was found that the adsorption capability remains high after several cycles of adsorption-desorption process.

  18. Antidepressant-like effects of fractions, essential oil, carnosol and betulinic acid isolated from Rosmarinus officinalis L.

    PubMed

    Machado, Daniele G; Cunha, Mauricio P; Neis, Vivian B; Balen, Grasiela O; Colla, André; Bettio, Luis E B; Oliveira, Agatha; Pazini, Francis Leonardo; Dalmarco, Juliana B; Simionatto, Edésio Luiz; Pizzolatti, Moacir G; Rodrigues, Ana Lúcia S

    2013-01-15

    The aim of this study was to investigate the antidepressant-like effect of fractions from Rosmarinus officinalis L.: ethyl acetate 1 and 2 (AcOEt1 and 2), hexane (HEX), ethanolic (ET), and essential oil-free (EOF) fractions, as well as essential oil, the isolated compounds carnosol and betulinic acid in the tail suspension test, a predictive test of antidepressant activity. Swiss mice were acutely administered by oral route (p.o.) with fractions, essential oil or isolated compounds, 60 min before the tail suspension test or open-field test. All of them produced a significant antidepressant-like effect: AcOEt1, ET, EOF fractions and essential oil (0.1-100mg/kg, p.o); HEX (0.1-10mg/kg, p.o) and AcOEt2 fraction (0.1-1mg/kg, p.o), carnosol (0.01-0.1mg/kg, p.o.) isolated from the HEX fraction and betulinic acid (10mg/kg, p.o.), isolated from the AcOEt1 and AcOEt2 fractions. No psychostimulant effect was shown in the open-field test, indicating that the effects in the tail suspension test are specific. This study suggests that carnosol and betulinic acid could be responsible for the anti-immobility effect of extracts from R. officinalis.

  19. Comparative evaluation of essential fatty acid composition of mothers' milk of some urban and suburban regions of West Bengal, India.

    PubMed

    Roy, Susmita; Dhar, Pubali; Ghosh, Santinath

    2012-12-01

    This study investigated the fatty acid composition of lipid present in breast milk of mothers residing in urban and suburban regions of West Bengal with special emphasis on n-6 and n-3 polyunsaturated fatty acids, which played a crucial role in the growth and development of neonates. Milk samples collected from 135 mothers of middle income group (average monthly income around 'Rs 10,000/-') were analysed by gas liquid chromatography after extraction and transmethylation to determine fatty acid composition. Information about the dietary intake of individual mothers was obtained through food frequency questionnaire. The fractions of n-6 and n-3 polyunsaturated fatty acids available in milk of urban mothers were 13.59 ± 0.94 and 3.65 ± 0.49, respectively, and in suburban mothers 12.74 ± 0.89 and 4.36 ± 0.39, respectively. The green leafy vegetables, fishes and vegetable oils were the major sources of essential fatty acids in the diet of the experimental groups of Bengali mothers. This study revealed a relationship between the alimentary habits of mothers and the concentration of essential fatty acids in breast milk of Bengali mothers.

  20. Isomerization of HNO to HON in the singlet state assisted by amino acid residues and/or water molecules

    NASA Astrophysics Data System (ADS)

    Shi, Junyou; Li, Ping; Bu, Yuxiang; Wang, Weihua; Mou, Zhaoxia; Song, Rui

    The effects of amino acid residues in the presence or absence of water molecules on the isomerization of the singlet state of HNO/HON have been systematically investigated at the B3LYP/6-311++G** level of theory. The structural characteristics, proton transfer (PT) mechanisms, and the corresponding thermodynamic and kinetic parameters, have been discussed, respectively. All the optimized complexes have been characterized by the ring structures through the intermolecular H-bonds. The origin of the increase in N bond H stretching frequency (blue shifts) occurring in the reactants has also been investigated using the natural bonding orbital (NBO) analyses, which is mainly attributed to the decrease of the electron densities in the antibonding orbital of the N bond H bonds as well as the increase of the polarization of the N bond H bond. All the PTs proceed with the concerted mechanisms since no ionic intermediates have been located during PT processes. At the same time, the cooperative effects of amino acid residues and water molecules on the selected PT processes have been observed, where the PTs assisted solely by the selected residues cannot occur without the participation of the water molecule. Overall, the introductions of one or two water molecules are more favorable for the isomerization of HNO assisted by the amino acid residues.

  1. Acidic Residues Control the Dimerization of the N-terminal Domain of Black Widow Spiders’ Major Ampullate Spidroin 1

    NASA Astrophysics Data System (ADS)

    Bauer, Joschka; Schaal, Daniel; Eisoldt, Lukas; Schweimer, Kristian; Schwarzinger, Stephan; Scheibel, Thomas

    2016-09-01

    Dragline silk is the most prominent amongst spider silks and comprises two types of major ampullate spidroins (MaSp) differing in their proline content. In the natural spinning process, the conversion of soluble MaSp into a tough fiber is, amongst other factors, triggered by dimerization and conformational switching of their helical amino-terminal domains (NRN). Both processes are induced by protonation of acidic residues upon acidification along the spinning duct. Here, the structure and monomer-dimer-equilibrium of the domain NRN1 of Latrodectus hesperus MaSp1 and variants thereof have been investigated, and the key residues for both could be identified. Changes in ionic composition and strength within the spinning duct enable electrostatic interactions between the acidic and basic pole of two monomers which prearrange into an antiparallel dimer. Upon naturally occurring acidification this dimer is stabilized by protonation of residue E114. A conformational change is independently triggered by protonation of clustered acidic residues (D39, E76, E81). Such step-by-step mechanism allows a controlled spidroin assembly in a pH- and salt sensitive manner, preventing premature aggregation of spider silk proteins in the gland and at the same time ensuring fast and efficient dimer formation and stabilization on demand in the spinning duct.

  2. Acidic Residues Control the Dimerization of the N-terminal Domain of Black Widow Spiders’ Major Ampullate Spidroin 1

    PubMed Central

    Bauer, Joschka; Schaal, Daniel; Eisoldt, Lukas; Schweimer, Kristian; Schwarzinger, Stephan; Scheibel, Thomas

    2016-01-01

    Dragline silk is the most prominent amongst spider silks and comprises two types of major ampullate spidroins (MaSp) differing in their proline content. In the natural spinning process, the conversion of soluble MaSp into a tough fiber is, amongst other factors, triggered by dimerization and conformational switching of their helical amino-terminal domains (NRN). Both processes are induced by protonation of acidic residues upon acidification along the spinning duct. Here, the structure and monomer-dimer-equilibrium of the domain NRN1 of Latrodectus hesperus MaSp1 and variants thereof have been investigated, and the key residues for both could be identified. Changes in ionic composition and strength within the spinning duct enable electrostatic interactions between the acidic and basic pole of two monomers which prearrange into an antiparallel dimer. Upon naturally occurring acidification this dimer is stabilized by protonation of residue E114. A conformational change is independently triggered by protonation of clustered acidic residues (D39, E76, E81). Such step-by-step mechanism allows a controlled spidroin assembly in a pH- and salt sensitive manner, preventing premature aggregation of spider silk proteins in the gland and at the same time ensuring fast and efficient dimer formation and stabilization on demand in the spinning duct. PMID:27681031

  3. Preparation of a novel carbon-based solid acid from cassava stillage residue and its use for the esterification of free fatty acids in waste cooking oil.

    PubMed

    Wang, Lingtao; Dong, Xiuqin; Jiang, Haoxi; Li, Guiming; Zhang, Minhua

    2014-04-01

    A novel carbon-based solid acid catalyst was prepared by the sulfonation of incompletely carbonized cassava stillage residue (CSR) with concentrated sulfuric acid, and employed to catalyze the esterification of methanol and free fatty acids (FFAs) in waste cooking oil (WCO). The effects of the carbonization and the sulfonation temperatures on the pore structure, acid density and catalytic activity of the CSR-derived catalysts were systematically investigated. Low temperature carbonization and high temperature sulfonation can cause the collapse of the carbon framework, while high temperature carbonization is not conducive to the attachment of SO3H groups on the surface. The catalyst showed high catalytic activity for esterification, and the acid value for WCO is reduced to below 2mg KOH/g after reaction. The activity of catalyst can be well maintained after five cycles. CSR can be considered a promising raw material for the production of a new eco-friendly solid acid catalyst.

  4. Direct fermentation of potato starch and potato residues to lactic acid by Geobacillus stearothermophilus under non-sterile conditions

    PubMed Central

    Smerilli, Marina; Neureiter, Markus; Wurz, Stefan; Haas, Cornelia; Frühauf, Sabine; Fuchs, Werner

    2015-01-01

    BACKGROUND Lactic acid is an important biorefinery platform chemical. The use of thermophilic amylolytic microorganisms to produce lactic acid by fermentation constitutes an efficient strategy to reduce operating costs, including raw materials and sterilization costs. RESULTS A process for the thermophilic production of lactic acid by Geobacillus stearothermophilus directly from potato starch was characterized and optimized. Geobacillus stearothermophilus DSM 494 was selected out of 12 strains screened for amylolytic activity and the ability to form lactic acid as the major product of the anaerobic metabolism. In total more than 30 batches at 3–l scale were run at 60 °C under non-sterile conditions. The process developed produced 37 g L−1 optically pure (98%) L-lactic acid in 20 h from 50 g L−1 raw potato starch. As co-metabolites smaller amounts (<7% w/v) of acetate, formate and ethanol were formed. Yields of lactic acid increased from 66% to 81% when potato residues from food processing were used as a starchy substrate in place of raw potato starch. CONCLUSIONS Potato starch and residues were successfully converted to lactic acid by G. stearothermophilus. The process described in this study provides major benefits in industrial applications and for the valorization of starch-rich waste streams. © 2015 The Authors.Journal of Chemical Technology & Biotechnology published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry. PMID:25937690

  5. Neutralization of acidic residues in helix II stabilizes the folded conformation of acyl carrier protein and variably alters its function with different enzymes.

    PubMed

    Gong, Huansheng; Murphy, Anne; McMaster, Christopher R; Byers, David M

    2007-02-16

    Acyl carrier protein (ACP), a small protein essential for bacterial growth and pathogenesis, interacts with diverse enzymes during the biosynthesis of fatty acids, phospholipids, and other specialized products such as lipid A. NMR and hydrodynamic studies have previously shown that divalent cations stabilize native helical ACP conformation by binding to conserved acidic residues at two sites (A and B) at either end of the "recognition" helix II. To examine the roles of these amino acids in ACP structure and function, site-directed mutagenesis was used to replace individual site A (Asp-30, Asp-35, Asp-38) and site B (Glu-47, Glu-53, Asp-56) residues in recombinant Vibrio harveyi ACP with the corresponding amides, along with combined mutations at each site (SA, SB) or both sites (SA/SB). Like native V. harveyi ACP, all individual mutants were unfolded at neutral pH but adopted a helical conformation in the presence of millimolar Mg(2+) or upon fatty acylation. Mg(2+) binding to sites A or B independently stabilized native ACP conformation, whereas mutant SA/SB was folded in the absence of Mg(2+), suggesting that charge neutralization is largely responsible for ACP stabilization by divalent cations. Asp-35 in site A was critical for holo-ACP synthase activity, while acyl-ACP synthetase and UDP-N-acetylglucosamine acyltransferase (LpxA) activities were more affected by mutations in site B. Both sites were required for fatty acid synthase activity. Overall, our results indicate that divalent cation binding site mutations have predicted effects on ACP conformation but unpredicted and variable consequences on ACP function with different enzymes.

  6. Chemical composition and antibacterial properties of essential oil and fatty acids of different parts of Ligularia persica Boiss

    PubMed Central

    Mohadjerani, Maryam; Hosseinzadeh, Rahman; Hosseini, Maryam

    2016-01-01

    Objective: The objective of this research was to investigate the chemical composition and antibacterial activities of the fatty acids and essential oil from various parts of Ligularia persica Boiss (L. persica) growing wild in north of Iran. Materials and Methods: Essential oils were extracted by using Clevenger-type apparatus. Antibacterial activity was tested on two Gram-positive and two Gram-negative bacteria by using micro dilution method. Results: GC and GC∕MS analysis of the oils resulted in detection of 94%, 96%, 93%, 99% of the total essential oil of flowers, stems, roots and leaves, respectively. The main components of flowers oil were cis-ocimene (15.4%), β-myrcene (4.4%), β-ocimene (3.9%), and γ-terpinene (5.0%). The major constituents of stems oil were β-phellandrene (5.4%), β-cymene (7.0%), valencene (3.9%). The main compounds of root oil were fukinanolid (17.0%), α-phellandrene (11.5%) and Β-selinene (5.0%) and in the case of leaves oil were cis-ocimene (4.8%), β-ocimene (4.9%), and linolenic acid methyl ester (4.7%). An analysis by GC-FID and GC-MS on the fatty-acid composition of the different parts of L. persica showed that major components were linoleic acid (11.3-31.6%), linolenic acid (4.7-21.8%) and palmitic acid (7.2-23.2%). Saturated fatty acids were found in lower amounts than unsaturated ones. The least minimum inhibition concentration (MIC) of the L. persica was 7.16 μg/ml against Pseudomonas aeruginosa. Conclusion: Our study indicated that the essential oil from L. persica stems and flowers showed high inhibitory effect on the Gram negative bacteria. The results also showed that fatty acids from the stems and leaves contained a high amount of poly-unsaturated fatty acids (PUFAs). PMID:27462560

  7. The highly conserved aspartic acid residue between hypervariable regions 1 and 2 of human immunodeficiency virus type 1 gp120 is important for early stages of virus replication.

    PubMed Central

    Wang, W K; Essex, M; Lee, T H

    1995-01-01

    Between hypervariable regions V1 and V2 of human immunodeficiency virus type 1 (HIV-1) gp120 lies a cluster of relatively conserved residues. The contribution of nine charged residues in this region to virus infectivity was evaluated by single-amino-acid substitutions in an infectious provirus clone. Three of the HIV-1 mutants studied had slower growth kinetics than the wild-type virus. The delay was most pronounced in a mutant with an alanine substituted for an aspartic acid residue at position 180. This aspartic acid is conserved by all HIV-1 isolates with known nucleotide sequences. Substitutions with three other residues at this position, including a negatively charged glutamic acid, all affected virus infectivity. The defect identified in these mutants suggests that this aspartic acid residue is involved in the early stages of HIV-1 replication. PMID:7983752

  8. A Mutational Analysis of the Active Site Loop Residues in cis-3-Chloroacrylic Acid Dehalogenase

    PubMed Central

    Schroeder, Gottfried K.; Huddleston, Jamison P.; Johnson, William H.; Whitman, Christian P.

    2013-01-01

    cis -3-Chloroacrylic acid dehalogenase (cis-CaaD) from Pseudomonas pavonaceae 170 and a homologue from Corynebacterium glutamicum designated Cg10062 share 34% sequence identity (54% similarity). The former catalyzes a key step in a bacterial catabolic pathway for the nematocide 1,3-dichloropropene, whereas the latter has no known biological activity. Although Cg10062 has the six active site residues (Pro-1, His-28, Arg-70, Arg-73, Tyr-103, Glu-114) that are critical for cis-CaaD activity, it shows only a low level cis-CaaD activity and lacks the specificity of cis-CaaD: Cg10062 processes both isomers of 3-chloroacrylate with a preference for the cis-isomer. Although the basis for these differences is unknown, a comparison of the crystal structures of the enzymes covalently modified by an adduct resulting from their incubation with the same inhibitor offers a possible explanation. A 6-residue active site loop in cis-CaaD shows a strikingly different conformation from that observed in Cg10062: the loop closes down on the active site of cis-CaaD, but not on that of Cg10062. In order to examine what this loop might contribute to cis-CaaD catalysis and specificity, the residues were changed individually to those found in Cg10062. Subsequent kinetic and mechanistic analysis suggests that the T34A mutant of cis-CaaD is more Cg10062-like. The mutant enzyme shows a 4-fold increase in Km (using cis-3-bromoacrylate), but not to the degree observed for Cg10062 (687-fold). The mutation also causes a 4-fold decrease in the burst rate (compared to the wild type cis-CaaD), whereas Cg10062 shows no burst rate. More telling is the reaction of the T34A mutant of cis-CaaD with the alternate substrate, 2,3-butadienoate. In the presence of NaBH4 and the allene, cis-CaaD is completely inactivated after one turnover due to the covalent modification of Pro-1. The same experiment with Cg10062 does not result in the covalent modification of Pro-1. The different outcomes are attributed to

  9. Identification of amino acid residues that determine the substrate specificity of mammalian membrane-bound front-end fatty acid desaturases[S

    PubMed Central

    Watanabe, Kenshi; Ohno, Makoto; Taguchi, Masahiro; Kawamoto, Seiji; Ono, Kazuhisa; Aki, Tsunehiro

    2016-01-01

    Membrane-bound desaturases are physiologically and industrially important enzymes that are involved in the production of diverse fatty acids such as polyunsaturated fatty acids and their derivatives. Here, we identified amino acid residues that determine the substrate specificity of rat Δ6 desaturase (D6d) acting on linoleoyl-CoA by comparing its amino acid sequence with that of Δ5 desaturase (D5d), which converts dihomo-γ-linolenoyl-CoA. The N-terminal cytochrome b5-like domain was excluded as a determinant by domain swapping analysis. Substitution of eight amino acid residues (Ser209, Asn211, Arg216, Ser235, Leu236, Trp244, Gln245, and Val344) of D6d with the corresponding residues of D5d by site-directed mutagenesis switched the substrate specificity from linoleoyl-CoA to dihomo-γ-linolenoyl-CoA. In addition, replacement of Leu323 of D6d with Phe323 on the basis of the amino acid sequence of zebra fish Δ5/6 bifunctional desaturase was found to render D6d bifunctional. Homology modeling of D6d using recent crystal structure data of human stearoyl-CoA (Δ9) desaturase revealed that Arg216, Trp244, Gln245, and Leu323 are located near the substrate-binding pocket. To our knowledge, this is the first report on the structural basis of the substrate specificity of a mammalian front-end fatty acid desaturase, which will aid in efficient production of value-added fatty acids. PMID:26590171

  10. Myrtus communis berry color morphs: a comparative analysis of essential oils, fatty acids, phenolic compounds, and antioxidant activities.

    PubMed

    Messaoud, Chokri; Boussaid, Mohamed

    2011-02-01

    Extracts of mature dark blue and white berries from two Tunisian Myrtus communis morphs growing at the same site were assessed for their essential-oil and fatty-acid compositions, phenolic contents, and antioxidant activities. The GC and GC/MS analyses of the essential oils allowed the identification of 33 constituents. The oils from the dark blue fruits showed high percentages of α-pinene (11.1%), linalool (11.6%), α-terpineol (15.7%), methyl eugenol (6.2%), and geraniol (3.7%). Myrtenyl acetate (20.3%) was found to be the major compound in the oils from white berries. GC Analysis of the pericarp and seed fatty acids showed that the polyunsaturated fatty acids constituted the major fraction (54.3-78.1%). The highest percentages of linoleic acid (78.0%) and oleic acid (20.0%) were observed in the seeds and the pericarps of the white fruits, respectively. The total phenol, flavonoid, and flavonol contents and the concentration of the eight anthocyanins, identified by HPLC analysis, were significantly higher in the dark blue fruits. All extracts showed a substantial antioxidant activity, assessed by the free radical-scavenging activity and the ferric reducing power, with the dark blue fruit extracts being more effective.

  11. T Cell Determinants Incorporating [beta]-Amino Acid Residues Are Protease Resistant and Remain Immunogenic In Vivo

    SciTech Connect

    Webb, Andrew I.; Dunstone, Michelle A.; Williamson, Nicholas A.; Price, Jason D.; Kauwe, Andreade; Chen, Weisan; Oakley, Aaron; Perlmutter, Patrick; McCluskey, James; Aguilar, Marie-Isabel; Rossjohn, Jamie; Purcell, Anthony W.

    2010-07-20

    A major hurdle in designing successful epitope-based vaccines resides in the delivery, stability, and immunogenicity of the peptide immunogen. The short-lived nature of unmodified peptide-based vaccines in vivo limits their therapeutic application in the immunotherapy of cancers and chronic viral infections as well as their use in generating prophylactic immunity. The incorporation of {beta}-amino acids into peptides decreases proteolysis, yet its potential application in the rational design of T cell mimotopes is poorly understood. To address this, we have replaced each residue of the SIINFEKL epitope individually with the corresponding {beta}-amino acid and examined the resultant efficacy of these mimotopes. Some analogs displayed similar MHC binding and superior protease stability compared with the native epitope. Importantly, these analogs were able to generate cross-reactive CTLs in vivo that were capable of lysing tumor cells that expressed the unmodified epitope as a surrogate tumor Ag. Structural analysis of peptides in which anchor residues were substituted with {beta}-amino acids revealed the basis for enhanced MHC binding and retention of immunogenicity observed for these analogs and paves the way for future vaccine design using {beta}-amino acids. We conclude that the rational incorporation of {beta}-amino acids into T cell determinants is a powerful alternative to the traditional homologous substitution of randomly chosen naturally occurring {alpha}-amino acids, and these mimotopes may prove particularly useful for inclusion in epitope-based vaccines.

  12. Residual cadmium forms in acid-extracted anaerobically digested sewage sludge

    SciTech Connect

    Feltz, R.E.; Logan, T.J.

    1985-01-01

    The effects of phosphorus and lime additions after acid extraction on residual Cd solubility and chemical forms in an anaerobically digested sewage sludge were investigated. High Cd content anaerobically digested sewage sludge was aerated and then acidified to pH 2 to solubilize Cd. After 18 h of acidification, the sludge was dewatered and the supernatant and solids separated. Seventy or more percent of the Cd was removed from the solids. Similar amounts of Ni, Mn and Zn were also removed, but Cu removal was only 26% and that of Pb was < 5%. Before liming the sludge was amended with rock phosphate (RP) or monocalcium phosphate (MCP). The RP was insoluble while MCP dissolved, providing a high level of phosphate ligand for Cd precipitation or coprecipitation. Estimated sludge solution solubility products for major Fe, Al and Ca phosphates showed that several of these minerals could have precipitated with P addition, especially with MCP, and Cd may have coprecipitated with these solid phases. Cadmium phosphate may also have been formed in the MCP sludge. Chemical fractionation indicated that 50% of the Cd in the aerated unextracted sludge existed as inorganic precipitates with another 40% Na/sub 4/P/sub 2/O/sub 7/ extractable. Acidification solubilized 98% of the inorganic Cd and 86% of the organically bound Cd. Seventy-nine percent of the Cd remaining in the dewatered acidified sludge was in the KNO/sub 3/ extractable (exchangeable) fraction. Liming redistributed the Cd with 13 to 19% as inorganic precipitates, 70 to 85% organically bound and < 3% in the exchangeable fraction. Phosphate addition had no significant effect on Cd fractionation.

  13. Mutation in aspartic acid residues modifies catalytic and haemolytic activities of Bacillus cereus sphingomyelinase.

    PubMed Central

    Tamura, H; Tameishi, K; Yamada, A; Tomita, M; Matsuo, Y; Nishikawa, K; Ikezawa, H

    1995-01-01

    Four aspartic acid residues (Asp126, Asp156, Asp233 and Asp295) of Bacillus cereus sphingomyelinase (SMase) in the conservative regions were changed to glycine by in vitro mutagenesis, and the mutant SMases [D126G (Asp126-->Gly etc.), D156G, D233G and D295G] were produced in Bacillus brevis 47, a protein-producing strain. The sphingomyelin (SM)-hydrolysing activity of D295G was completely abolished and those of D126G and D156G were reduced by more than 80%, whereas that of D233G was not so profoundly affected. Two mutant enzymes (D126G and D156G) were purified and characterized further. The hydrolytic activities of D126G and D156G toward four phosphocholine-containing substrates with different hydrophobicities, SM, 2-hexadecanoylamino-4-nitrophenylphosphocholine(HNP), lysophosphatidylcholine (lysoPC) and p-nitro-phenylphosphocholine (p-NPPC), were compared with those of the wild-type. The activity of D126G toward water-soluble p-NPPC was comparable with that of the wild-type. On the other hand, D156G catalysed the hydrolysis of hydrophilic substrates such as HNP and p-NPPC more efficiently (> 4-fold) than the wild-type. These results suggested that Asp126 and Asp156, located in the highly conserved region, may well be involved in a substrate recognition process rather than catalytic action. Haemolytic activities of the mutant enzymes were found to be parallel with their SM-hydrolysing activities. Two regions, including the C-terminal region containing Asp295, were found to show considerable sequence identity with the corresponding regions of bovine pancreatic DNase I. Structural predictions indicated structural similarity between SMase and DNase I. An evolutionary relationship based on the catalytic function was suggested between the structures of these two phosphodiesterases. Images Figure 2 Figure 3 Figure 4 Figure 6 PMID:7639690

  14. Reuse of acid coagulant-recovered drinking waterworks sludge residual to remove phosphorus from wastewater

    NASA Astrophysics Data System (ADS)

    Yang, Lan; Wei, Jie; Zhang, Yumei; Wang, Jianli; Wang, Dongtian

    2014-06-01

    Acid coagulant-recovered drinking waterworks sludge residual (DWSR) is a waste product from drinking waterworks sludge (DWS) treatment with acid for coagulant recovery. In this study, we evaluated DWSR as a potential phosphorus (P) removing material in wastewater treatment by conducting a series of batch and semi-continuous tests. Batch tests were carried out to study the effects of pH, initial concentration, and sludge dose on P removal. Batch test results showed that the P removal efficiency of DWSR was highly dependent on pH. Calcinated DWSR (C-DWSR) performed better in P removal than DWSR due to its higher pH. At an optimum initial pH value of 5-6 and a sludge dose of 10 g/L, the P removal rates of DWSR and DWS decreased from 99% and 93% to 84% and 14%, respectively, and the specific P uptake of DWSR and DWS increased from 0.19 and 0.19 mg P/g to 33.60 and 5.72 mg P/g, respectively, when the initial concentration was increased from 2 to 400 mg/L. The effective minimum sludge doses of DWSR and DWS were 0.5 g/L and 10 g/L, respectively, when the P removal rates of 90% were obtained at an initial concentration of 10 mg/L. Results from semi-continuous test indicated that P removal rates over 99% were quickly achieved for both synthetic and actual wastewater (lake water and domestic sewage). These rates could be maintained over a certain time under a certain operational conditions including sludge dose, feed flow, and initial concentration. The physicochemical properties analysis results showed that the contents of aluminum (Al) and iron (Fe) in DWSR were reduced by 50% and 70%, respectively, compared with DWS. The insoluble Al and Fe hydroxide in DWS converted into soluble Al and Fe in DWSR. Metal leaching test results revealed that little soluble Al and Fe remained in effluent when DWSR was used for P removal. We deduced that chemical precipitation might be the major action for P removal by DWSR and that adsorption played only a marginal role.

  15. Influence of ageing and essential amino acids on quantitative patterns of troponin T alternative splicing in human skeletal muscle

    PubMed Central

    Berg, Arthur; Drummond, Micah J.; Rasmussen, Blake B.; Kimball, Scot R.

    2015-01-01

    Ageing is associated with a loss of skeletal muscle performance, a condition referred to as sarcopenia. In part, the age-related reduction in performance is due to a selective loss in muscle fiber mass, but mass-independent effects have also been demonstrated. An important mass-independent determinant of muscle performance is the pattern of expression of isoforms of proteins that participate in muscle contraction, e.g. the troponins. In the present study we tested the hypothesis that ageing impairs alternative splicing of the pre-mRNA encoding fast troponin T (Tnnt3) in human vastus lateralis muscle. Furthermore, we hypothesized that resistance exercise alone or in combination with consumption of essential amino acids will attenuate age-associated effects on Tnnt3 alternative splicing. Our results indicate that ageing negatively affects the pattern of Tnnt3 pre-mRNA alternative splicing in a manner that correlates quantitatively with age-associated reductions in muscle performance. Interestingly, whereas vastus lateralis Tnnt3 alternative splicing was unaffected by a bout of resistance exercise 24 hour prior to muscle biopsy, ingestion of a mixture of essential amino acids after resistance exercise resulted in a significant shift in the pattern of Tnnt3 spliceform expression in both age groups to one predicted to promote greater muscle performance. We conclude that essential amino acid supplementation after resistance exercise may provide a means to reduce impairments in skeletal muscle quality during ageing in humans. PMID:26201856

  16. Localization of key amino acid residues in the dominant conformational epitopes on thyroid peroxidase recognized by mouse monoclonal antibodies.

    PubMed

    Godlewska, Marlena; Czarnocka, Barbara; Gora, Monika

    2012-09-01

    Autoantibodies to thyroid peroxidase (TPO), the major target autoantigen in autoimmune thyroid diseases, recognize conformational epitopes limited to two immunodominant regions (IDRs) termed IDR-A and -B. The apparent restricted heterogeneity of TPO autoantibodies was discovered using TPO-specific mouse monoclonal antibodies (mAbs) and later confirmed by human recombinant Fabs. In earlier studies we identified key amino acids crucial for the interaction of human autoantibodies with TPO. Here we show the critical residues that participate in binding of five mAbs to the conformational epitopes on the TPO surface. Using ELISA we tested the reactivity of single and multiple TPO mutants expressed in CHO cells with a panel of mAbs specifically recognizing IDR-A (mAb 2 and 9) and IDR-B (mAb 15, 18, 64). We show that antibodies recognizing very similar regions on the TPO surface may interact with different sets of residues. We found that residues K713 and E716 contribute to the interaction between mAb 2 and TPO. The epitope for mAb 9 is critically dependent on residues R646 and E716. Moreover, we demonstrate that amino acids E604 and D630 are part of the functional epitope for mAb 15, and amino acids D624 and K627 for mAb 18. Finally, residues E604, D620, D624, K627, and D630 constitute the epitope for mAb 64. This is the first detailed study identifying the key resides for binding of mAbs 2, 9, 15, 18, and 64. Better understanding of those antibodies' specificity will be helpful in elucidating the properties of TPO as an antigen in autoimmune disorders.

  17. Dynamics of linker residues modulate the nucleic acid binding properties of the HIV-1 nucleocapsid protein zinc fingers.

    PubMed

    Zargarian, Loussiné; Tisné, Carine; Barraud, Pierre; Xu, Xiaoqian; Morellet, Nelly; René, Brigitte; Mély, Yves; Fossé, Philippe; Mauffret, Olivier

    2014-01-01

    The HIV-1 nucleocapsid protein (NC) is a small basic protein containing two zinc fingers (ZF) separated by a short linker. It is involved in several steps of the replication cycle and acts as a nucleic acid chaperone protein in facilitating nucleic acid strand transfers occurring during reverse transcription. Recent analysis of three-dimensional structures of NC-nucleic acids complexes established a new property: the unpaired guanines targeted by NC are more often inserted in the C-terminal zinc finger (ZF2) than in the N-terminal zinc finger (ZF1). Although previous NMR dynamic studies were performed with NC, the dynamic behavior of the linker residues connecting the two ZF domains remains unclear. This prompted us to investigate the dynamic behavior of the linker residues. Here, we collected 15N NMR relaxation data and used for the first time data at several fields to probe the protein dynamics. The analysis at two fields allows us to detect a slow motion occurring between the two domains around a hinge located in the linker at the G35 position. However, the amplitude of motion appears limited in our conditions. In addition, we showed that the neighboring linker residues R29, A30, P31, R32, K33 displayed restricted motion and numerous contacts with residues of ZF1. Our results are fully consistent with a model in which the ZF1-linker contacts prevent the ZF1 domain to interact with unpaired guanines, whereas the ZF2 domain is more accessible and competent to interact with unpaired guanines. In contrast, ZF1 with its large hydrophobic plateau is able to destabilize the double-stranded regions adjacent to the guanines bound by ZF2. The linker residues and the internal dynamics of NC regulate therefore the different functions of the two zinc fingers that are required for an optimal chaperone activity.

  18. Treatment of air pollution control residues with iron rich waste sulfuric acid: does it work for antimony (Sb)?

    PubMed

    Okkenhaug, Gudny; Breedveld, Gijs D; Kirkeng, Terje; Lægreid, Marit; Mæhlum, Trond; Mulder, Jan

    2013-03-15

    Antimony (Sb) in air pollution control (APC) residues from municipal solid waste incineration has gained increased focus due to strict Sb leaching limits set by the EU landfill directive. Here we study the chemical speciation and solubility of Sb at the APC treatment facility NOAH Langøya (Norway), where iron (Fe)-rich sulfuric acid (∼3.6M, 2.3% Fe(II)), a waste product from the industrial extraction of ilmenite, is used for neutralization. Antimony in water extracts of untreated APC residues occurred exclusively as pentavalent antimonate, even at low pH and Eh values. The Sb solubility increased substantially at pH<10, possibly due to the dissolution of ettringite (at alkaline pH) or calcium (Ca)-antimonate. Treated APC residues, stored anoxically in the laboratory, simulating the conditions at the NOAH Langøya landfill, gave rise to decreasing concentrations of Sb in porewater, occurring exclusively as Sb(V). Concentrations of Sb decreased from 87-918μgL(-1) (day 3) to 18-69μgL(-1) (day 600). We hypothesize that an initial sorption of Sb to Fe(II)-Fe(III) hydroxides (green rust) and eventually precipitation of Ca- and Fe-antimonates (tripuhyite; FeSbO4) occurred. We conclude that Fe-rich, sulfuric acid waste is efficient to immobilize Sb in APC residues from waste incineration.

  19. Two amino acid residues confer type specificity to a neutralizing, conformationally dependent epitope on human papillomavirus type 11.

    PubMed Central

    Ludmerer, S W; Benincasa, D; Mark, G E

    1996-01-01

    Characterization of virus binding by neutralizing antibodies is important both in understanding early events in viral infectivity and in development of vaccines. Neutralizing monoclonal antibodies (MAbs) to human papillomavirus type 11 (HPV11) have been described, but mapping the binding site has been difficult because of the conformational nature of key type-specific neutralization epitopes on the L1 coat protein. We have determined those residues of the L1 protein of HPV11 which confer type specificity to the binding of HPV11-neutralizing MAbs. Binding of three HPV11-specific neutralizing MAbs could be redirected to HPV6 L1 virus-like particles in which as few as two substitutions of corresponding amino acid residues from HPV11 L1 have been made, thus demonstrating the importance of these residues to MAb binding through the transfer of a conformationally dependent epitope. In addition, a fourth neutralizing MAb could be distinguished from the other neutralizing MAbs in terms of the amino acid residues which affect binding, suggesting the possibility that it neutralizes HPV11 through a different mechanism. PMID:8676509

  20. Spatial Patterns and Temperature Predictions of Tuna Fatty Acids: Tracing Essential Nutrients and Changes in Primary Producers

    PubMed Central

    Pethybridge, Heidi R.; Parrish, Christopher C.; Morrongiello, John; Young, Jock W.; Farley, Jessica H.; Gunasekera, Rasanthi M.; Nichols, Peter D.

    2015-01-01

    Fatty acids are among the least understood nutrients in marine environments, despite their profile as key energy components of food webs and that they are essential to all life forms. Presented here is a novel approach to predict the spatial-temporal distributions of fatty acids in marine resources using generalized additive mixed models. Fatty acid tracers (FAT) of key primary producers, nutritional condition indices and concentrations of two essential long-chain (≥C20) omega-3 fatty acids (EFA) measured in muscle of albacore tuna, Thunnus alalunga, sampled in the south-west Pacific Ocean were response variables. Predictive variables were: location, time, sea surface temperature (SST) and chlorophyll-a (Chla), and phytoplankton biomass at time of catch and curved fork length. The best model fit for all fatty acid parameters included fish length and SST. The first oceanographic contour maps of EFA and FAT (FATscapes) were produced and demonstrated clear geographical gradients in the study region. Predicted changes in all fatty acid parameters reflected shifts in the size-structure of dominant primary producers. Model projections show that the supply and availability of EFA are likely to be negatively affected by increases in SST especially in temperate waters where a 12% reduction in both total fatty acid content and EFA proportions are predicted. Such changes will have large implications for the availability of energy and associated health benefits to high-order consumers. Results convey new concerns on impacts of projected climate change on fish-derived EFA in marine systems. PMID:26135308

  1. Biosynthesis of D-alanyl-lipoteichoic acid by Lactobacillus casei: interchain transacylation of D-alanyl ester residues

    SciTech Connect

    Childs, W.C. 3d.; Taron, D.J.; Neuhaus, F.C.

    1985-06-01

    Lipoteichoic acid (LTA) from Lactobacillus casei contains poly(glycerophosphate) substituted with D-alanyl ester residues. The distribution of these residues in the in vitro-synthesized polymer is uniform. Esterification of LTA with D-alanine may occur in one of two modes: (i) addition at random or (ii) addition at a defined locus in the poly(glycerophosphate) chain followed by redistribution of the ester residues. A time-dependent transacylation of these residues from D-(/sup 14/C)alanyl-lipophilic LTA to hydrophilic acceptor was observed. The hydrophilic acceptor was characterized as D-alanyl-hydrophilic LTA. This transacylation requires neither ATP nor the D-alanine incorporation system, i.e., the D-alanine activating enzyme and D-alanine:membrane acceptor ligase. No evidence for an enzyme-catalyzed transacylation reaction was observed. The authors propose that this process of transacylation may be responsible for the redistribution of D-alanyl residues after esterification to the poly(glycerophosphate). As a result, it is difficult to distinguish between these proposed modes of addition.

  2. A highly Conserved Aspartic Acid Residue of the Chitosanase from Bacillus Sp. TS Is Involved in the Substrate Binding.

    PubMed

    Zhou, Zhanping; Zhao, Shuangzhi; Liu, Yang; Chang, Zhengying; Ma, Yanhe; Li, Jian; Song, Jiangning

    2016-11-01

    The chitosanase from Bacillus sp. TS (CsnTS) is an enzyme belonging to the glycoside hydrolase family 8. The sequence of CsnTS shares 98 % identity with the chitosanase from Bacillus sp. K17. Crystallography analysis and site-direct mutagenesis of the chitosanase from Bacillus sp. K17 identified the important residues involved in the catalytic interaction and substrate binding. However, despite progress in understanding the catalytic mechanism of the chitosanase from the family GH8, the functional roles of some residues that are highly conserved throughout this family have not been fully elucidated. This study focused on one of these residues, i.e., the aspartic acid residue at position 318. We found that apart from asparagine, mutation of Asp318 resulted in significant loss of enzyme activity. In-depth investigations showed that mutation of this residue not only impaired enzymatic activity but also affected substrate binding. Taken together, our results showed that Asp318 plays an important role in CsnTS activity.

  3. Formation of [b3 - 1 + cat]+ ions from metal-cationized tetrapeptides containing beta-alanine, gamma-aminobutyric acid or epsilon-aminocaproic acid residues.

    PubMed

    Osburn, Sandra M; Ochola, Sila O; Talaty, Erach R; Van Stipdonk, Michael J

    2008-11-01

    The presence and position of a single beta-alanine (betaA), gamma-aminobutyric acid (gammaABu) or epsilon-aminocaproic acid (Cap) residue has been shown to have a significant influence on the formation of b(n)+ and y(n)+ product ions from a series of model, protonated peptides. In this study, we examined the effect of the same residues on the formation of analogous [b3 - 1 + cat]+ products from metal (Li+, Na+ and Ag+)-cationized peptides. The larger amino acids suppress formation of b3+ from protonated peptides with general sequence AAXG (where X = beta-alanine, gamma-aminobutyric acid or epsilon-aminocaproic acid), presumably because of the prohibitive effect of larger cyclic intermediates in the 'oxazolone' pathway. However, abundant [b3 - 1 + cat]+ products are generated from metal-cationized versions of AAXG. Using a group of deuterium-labeled and exchanged peptides, we found that formation of [b3 - 1 + cat]+ involves transfer of either amide or alpha-carbon position H atoms, and the tendency to transfer the atom from the alpha-carbon position increases with the size of the amino acid in position X. To account for the transfer of the H atom, a mechanism involving formation of a ketene product as [b3 - 1 + cat]+ is proposed.

  4. Plasmodium falciparum Field Isolates Commonly Use Erythrocyte Invasion Pathways That Are Independent of Sialic Acid Residues of Glycophorin A

    PubMed Central

    Okoyeh, Jude Nnaemeka; Pillai, C. R.; Chitnis, Chetan E.

    1999-01-01

    Erythrocyte invasion by malaria parasites is mediated by specific molecular interactions. Sialic acid residues of glycophorin A are used as invasion receptors by Plasmodium falciparum. In vitro invasion studies have demonstrated that some cloned P. falciparum lines can use alternate receptors independent of sialic acid residues of glycophorin A. It is not known if invasion by alternate pathways occurs commonly in the field. In this study, we used in vitro growth assays and erythrocyte invasion assays to determine the invasion phenotypes of 15 P. falciparum field isolates. Of the 15 field isolates tested, 5 multiply in both neuraminidase and trypsin-treated erythrocytes, 3 multiply in neuraminidase-treated but not trypsin-treated erythrocytes, and 4 multiply in trypsin-treated but not neuraminidase-treated erythrocytes; 12 of the 15 field isolates tested use alternate invasion pathways that are not dependent on sialic acid residues of glycophorin A. Alternate invasion pathways are thus commonly used by P. falciparum field isolates. Typing based on two polymorphic markers, MSP-1 and MSP-2, and two microsatellite markers suggests that only 1 of the 15 field isolates tested contains multiple parasite genotypes. Individual P. falciparum lines can thus use multiple invasion pathways in the field. These observations have important implications for malaria vaccine development efforts based on EBA-175, the P. falciparum protein that binds sialic acid residues of glycophorin A during invasion. It may be necessary to target parasite ligands responsible for the alternate invasion pathways in addition to EBA-175 to effectively block erythrocyte invasion by P. falciparum. PMID:10531229

  5. Structural and Functional Characterization of PseC, an Aminotransferase Involved in the Biosynthesis of Pseudaminic Acid, an Essential Flagellar Modification in Helicobacter Pylori

    SciTech Connect

    Schoenhofen,I.; Lunin, V.; Julien, J.; Li, Y.; Ajamian, E.; Matte, A.; Cygler, M.; Brisson, J.; Aubry, A.; et al.

    2006-01-01

    Helicobacter pylori flagellin is heavily glycosylated with the novel sialic acid-like nonulosonate, pseudaminic acid (Pse). The glycosylation process is essential for assembly of functional flagellar filaments and consequent bacterial motility. As motility is a key virulence factor for this and other important pathogens, the Pse biosynthetic pathway offers potential for novel therapeutic targets. From recent NMR analyses, we determined that the conversion of UDP-a-D-GlcNAc to the central intermediate in the pathway, UDP-4-amino-4,6-dideoxy-{beta}-L-AltNAc, proceeds by formation of UDP-2-acetamido-2,6-dideoxy-{beta}-L-arabino-4-hexulose by the dehydratase/epimerase PseB (HP0840) followed with amino transfer by the aminotransferase, PseC (HP0366). The central role of PseC in the H. pylori Pse biosynthetic pathway prompted us to determine crystal structures of the native protein, its complexes with pyridoxal phosphate alone and in combination with the UDP-4-amino-4,6-dideoxy-{beta}-L-AltNAc product, the latter being converted to the external aldimine form in the enzyme's active site. In the binding site, the AltNAc sugar ring adopts a 4C1 chair conformation which is different from the predominant 1C4 form found in solution. The enzyme forms a homodimer where each monomer contributes to the active site, and these structures have permitted the identification of key residues involved in stabilization, and possibly catalysis, of the {beta}-L-arabino intermediate during the amino transfer reaction. The essential role of Lys183 in the catalytic event was confirmed by site-directed mutagenesis. This work presents for the first time a nucleotide-sugar aminotransferase co-crystallized with its natural ligand, and in conjunction with the recent functional characterization of this enzyme, will assist in elucidating the aminotransferase reaction mechanism within the Pse biosynthetic pathway.

  6. Experimental study of the antithrombogenic behavior of Dacron vascular grafts coated with hydrophilic acrylic copolymers bearing salicylic acid residues.

    PubMed

    San Román, J; Buján, J; Bellón, J M; Gallardo, A; Escudero, M C; Jorge, E; de Haro, J; Alvarez, L; Castillo-Olivares, J L

    1996-09-01

    The objective of the present work was study of the behavior of active coatings of hydrophilic acrylic polymers bearing salicylic acid residues linked covalently to the macromolecular chains, after their application to woven and knitted Dacron vascular grafts. In vitro tests were carried out under dynamic flow conditions using equipment especially designed to reproduce physiologic conditions, to determine the retention of the coating using a saline solution. Ex vivo tests were carried out in an extracorporeal circuit using the dog as an animal model. The study of the deposition of platelets was followed by labeling of autologous platelets with 111In-oxine, as well as by analysis of the surfaces of the prostheses by scanning electron microscopy. An application of thin coatings of hydrophilic acrylic copolymers improves the antithrombogenicity of the vascular grafts with respect to the uncoated prosthesis. The presence of relatively small amounts of units bearing salicylic acid residues in the copolymer chains (5-20 wt %) gives good results when they are applied to woven and knitten Dacron meshes which have been quantified by analysis of the percentage of radiotracer on the surface of the vascular grafts tested in ex vivo experiments. The salicylic acid residues are released slowly to the medium by hydrolysis of the reversible covalent bonds of this compound to the acrylic macromolecular chains, which provides an additional antiaggregating effect for platelets. The polymeric coating forms a thin active film which improves the antithrombogenic properties of the surface of woven or knitted Dacron vascular grafts in ex vivo experiments.

  7. Sequence of the canine herpesvirus thymidine kinase gene: taxon-preferred amino acid residues in the alphaherpesviral thymidine kinases.

    PubMed

    Rémond, M; Sheldrick, P; Lebreton, F; Foulon, T

    1995-12-01

    Multiple sequence alignments of evolutionarily related proteins are finding increasing use as indicators of critical amino acid residues necessary for structural stability or involved in functional domains responsible for catalytic activities. In the past, a number of alignments have provided such information for the herpesviral thymidine kinases, for which three-dimensional structures are not yet available. We have sequenced the thymidine kinase gene of a canine herpesvirus, and with a multiple alignment have identified amino acids preferentially conserved in either of two taxons, the genera Varicellovirus and Simplexvirus, of the subfamily Alphaherpesvirinae. Since some regions of the thymidine kinases show otherwise elevated levels of substitutional tolerance, these conserved amino acids are candidates for critical residues which have become fixed through selection during the evolutionary divergence of these enzymes. Several pairs with distinctive patterns of distribution among the various viruses occur in or near highly conserved sequence motifs previously proposed to form the catalytic site, and we speculate that they may represent interacting, co-ordinately variable residues.

  8. Benefit-risk ratio of canned pacific saury (Cololabis saira) intake: Essential fatty acids vs. heavy metals.

    PubMed

    Anishchenko, O V; Sushchik, N N; Makhutova, O N; Kalachova, G S; Gribovskaya, I V; Morgun, V N; Gladyshev, M I

    2017-03-01

    Fatty acid (FA) and element contents were studied in 14 brands of canned (in its own juice and with sunflower oil) saury (Cololabis saira), a popular product of Russian market. Canned saury is a valuable source of essential polyunsaturated FA - eicosapentaenoic acid (EPA, 20:5n-3) and docosahexaenoic acid (DHA, 22:6n-3). To obtain personal daily dose of EPA + DHA of 1 g for prevention of cardiovascular diseases, neural and inflammatory disorders one needs to intake from 26 to 76 g of canned saury, as was calculated for studied brands. ICP-OES analysis of 24 elements showed that Pb concentration in one brand and Cd content in most of studied saury samples exceeded standards for fish meat established by the European Commission. However, values of hazard quotient, HQEFA, which estimate benefit-risk ratio of fish intake, indicate that canned saury is safe product for human nutrition.

  9. Target of rapamycin signalling mediates the lifespan-extending effects of dietary restriction by essential amino acid alteration.

    PubMed

    Emran, Sahar; Yang, Mingyao; He, Xiaoli; Zandveld, Jelle; Piper, Matthew D W

    2014-05-01

    Dietary restriction (DR), defined as a moderate reduction in food intake short of malnutrition, has been shown to extend healthy lifespan in a diverse range of organisms, from yeast to primates. Reduced signalling through the insulin/IGF-like (IIS) and Target of Rapamycin (TOR) signalling pathways also extend lifespan. InDrosophila melanogaster the lifespan benefits of DR can be reproduced by modulating only the essential amino acids in yeast based food. Here, we show that pharmacological downregulation of TOR signalling, but not reduced IIS, modulates the lifespan response to DR by amino acid alteration. Of the physiological responses flies exhibit upon DR, only increased body fat and decreased heat stress resistance phenotypes correlated with longevity via reduced TOR signalling. These data indicate that lowered dietary amino acids promote longevity via TOR, not by enhanced resistance to molecular damage, but through modified physiological conditions that favour fat accumulation.

  10. Simultaneous Determination of Essential Oil Components and Fatty Acids in Fennel using Gas Chromatography with a Polar Capillary Column.

    PubMed

    Najdoska-Bogdanov, Menče; Bogdanov, Jane B; Stefova, Marina

    2015-09-01

    Cultivated and wild growing samples of fennel (Foeniculum vulgare Mill., Apiaceae) from R. Macedonia were studied for their volatiles and fatty acid composition. The main essential oil components isolated via hydrodistillation were: trans-anethole (>80%), estragole (< 6%), limonene (< 6%), anisaldehyde (< 1%) and 0.5 % fenchone. An alternative method for characterization of both the non-polar volatile and non volatile fractions was developed using n-hexane and dichloromethane (3:1, v/v) in a Soxhlet extraction followed by transesterification. The obtained extracts were then characterized and the dominant fatty acid was 18:1 (petroselinic and oleic acid) 75.0-82.8%, followed by 18:2 (linoleic acid) 10.8-16.2% and other fatty acids: palmitic (4.3-6.9%), stearic (1.2-1.7%) and myristic (0-2.9%). The results for the volatile fraction after Soxhlet extraction and transesterification did not significantly differ from results obtained after hydrodistillation, especially for the main components (trans-anethole, estragole, fenchone and limonene), implying that the developed method can be used for simultaneous determination of volatiles and fatty acids.

  11. Identification of Respiratory Syncytial Virus Nonstructural Protein 2 Residues Essential for Exploitation of the Host Ubiquitin System and Inhibition of Innate Immune Responses

    PubMed Central

    Whelan, Jillian N.; Tran, Kim C.; van Rossum, Damian B.

    2016-01-01

    ABSTRACT Respiratory syncytial virus (RSV) is a leading cause of lower respiratory tract infection in young children worldwide. The RSV nonstructural protein 2 (NS2) is a multifunctional protein that primarily acts to antagonize the innate immune system by targeting STAT2 for proteasomal degradation. We investigated the structural determinants of NS2 important for interaction with the host ubiquitin system to degrade STAT2 during infection. We found that NS2 expression enhances ubiquitination of host proteins. Bioinformatics analysis provided a platform for identification of specific residues that limit NS2-induced ubiquitination. Combinations of multiple mutations displayed an additive effect on reducing NS2-induced ubiquitination. Using a reverse genetics system, we generated recombinant RSV (rRSV) containing NS2 ubiquitin mutations, which maintained their effect on ubiquitin expression during infection. Interestingly, STAT2 degradation activity was ablated in the NS2 ubiquitin mutant rRSV. In addition, NS2 ubiquitin mutations decreased rRSV replication, indicating a correlation between NS2's ubiquitin function and antagonism of innate immune signaling to enhance viral replication. Our approach of targeting NS2 residues required for NS2 inhibition of immune responses provides a mechanism for attenuating RSV for vaccine development. IMPORTANCE RSV has been circulating globally for more than 60 years, causing severe respiratory disease in pediatric, elderly, and immunocompromised populations. Production of a safe, effective vaccine against RSV is a public health priority. The NS2 protein is an effective target for prevention and treatment of RSV due to its antagonistic activity against the innate immune system. However, NS2-deleted RSV vaccine candidates rendered RSV overattenuated or poorly immunogenic. Alternatively, we can modify essential NS2 structural features to marginally limit viral growth while maintaining immune responses, providing the necessary balance

  12. The Hip Functional Retrieval after Elective Surgery May Be Enhanced by Supplemented Essential Amino Acids

    PubMed Central

    Baldissarro, Eleonora; Aquilani, Roberto; Boschi, Federica; Baiardi, Paola; Iadarola, Paolo; Fumagalli, Marco; Pasini, Evasio; Verri, Manuela; Dossena, Maurizia; Gambino, Arianna; Cammisuli, Sharon; Viglio, Simona

    2016-01-01

    It is not known whether postsurgery systemic inflammation and plasma amino acid abnormalities are still present during rehabilitation of individuals after elective hip arthroplasty (EHA). Sixty subjects (36 females; age 66.58 ± 8.37 years) were randomized to receive 14-day oral EAAs (8 g/day) or a placebo (maltodextrin). At admission to and discharge from the rehabilitation center, serum C-reactive protein (CRP) and venous plasma amino acid concentrations were determined. Post-EHA hip function was evaluated by Harris hip score (HHS) test. Ten matched healthy subjects served as controls. At baseline, all patients had high CRP levels, considerable reduction in several amino acids, and severely reduced hip function (HHS 40.78 ± 2.70 scores). After treatment, inflammation decreased both in the EAA group and in the placebo group. Only EAA patients significantly improved their levels of glycine, alanine, tyrosine, and total amino acids. In addition, they enhanced the rate of hip function recovery (HHS) (from baseline 41.8 ± 1.15 to 76.37 ± 6.6 versus baseline 39.78 ± 4.89 to 70.0 ± 7.1 in placebo one; p = 0.006). The study documents the persistence of inflammation and plasma amino acid abnormalities in post-EHA rehabilitation phase. EAAs enhance hip function retrieval and improve plasma amino acid abnormalities. PMID:27110573

  13. QTL mapping with different genetic systems for nine non-essential amino acids of cottonseeds.

    PubMed

    Liu, Haiying; Quampah, Alfred; Chen, Jinhong; Li, Jinrong; Huang, Zhuangrong; He, Qiuling; Shi, Chunhai; Zhu, Shuijin

    2017-03-18

    Amino acid is an important nutrient resource for both human and animals. Using a set of 188 RILs population derived from an elite hybrid cross of upland cotton cultivars 'HS46' × 'MARCABUCAG8US-1-88' and their immortal F2 (IF2) with reciprocal backcrosses BC1F1 and BC2F1 (BC) populations in two environments, the QTLs located on the embryo genome and maternal plant genome for nine amino acids of cottonseed were studied across environments. The QTL Network-CL-2.0-seed software was used to analyze the QTLs and their genetic effects for nine amino acids. A total of 56 QTLs for nine amino acids were detected in both populations, with many having over 5% of phenotypic variation. Ten of the total QTLs could be simultaneously found in the IF2 and BC populations. For most QTLs, the genetic effects from embryo genome were more important than those from maternal plant genome for the performance of nine amino acids. Significant embryo additive main effects and maternal additive main effect with their environment interaction effects from many QTLs were also found in present experiment. Some QTLs with larger phenotypic variation were important for improving the amino-acid contents in cottonseeds.

  14. Residual Chemoresponsiveness to Acids in the Superior Laryngeal Nerve in “Taste-Blind” (P2X2/P2X3 Double-KO) Mice

    PubMed Central

    Ohkuri, Tadahiro; Horio, Nao; Stratford, Jennifer M.; Finger, Thomas E.; Ninomiya, Yuzo

    2012-01-01

    Mice lacking both the P2X2 and the P2X3 purinergic receptors (P2X-dblKO) exhibit loss of responses to all taste qualities in the taste nerves innervating the tongue. Similarly, these mice exhibit a near total loss of taste-related behaviors in brief access tests except for a near-normal avoidance of acidic stimuli. This persistent avoidance of acids despite the loss of gustatory neural responses to sour was postulated to be due to continued responsiveness of the superior laryngeal (SL) nerve. However, chemoresponses of the larynx are attributable both to taste buds and to free nerve endings. In order to test whether the SL nerve of P2X-dblKO mice remains responsive to acids but not to other tastants, we recorded responses from the SL nerve in wild-type (WT) and P2X-dblKO mice. WT mice showed substantial SL responses to monosodium glutamate, sucrose, urea, and denatonium—all of which were essentially absent in P2X-dblKO animals. In contrast, the SL nerve of P2X-dblKO mice exhibited near-normal responses to citric acid (50 mM) although responsiveness of both the chorda tympani and the glossopharyngeal nerves to this stimulus were absent or greatly reduced. These results are consistent with the hypothesis that the residual avoidance of acidic solutions by P2X-dblKO mice may be attributable to the direct chemosensitivity of nerve fibers innervating the laryngeal epithelium and not to taste. PMID:22362867

  15. Apicoplast fatty acid synthesis is essential for pellicle formation at the end of cytokinesis in Toxoplasma gondii.

    PubMed

    Martins-Duarte, Érica S; Carias, Maira; Vommaro, Rossiane; Surolia, Namita; de Souza, Wanderley

    2016-09-01

    The apicomplexan protozoan Toxoplasma gondii, the causative agent of toxoplasmosis, harbors an apicoplast, a plastid-like organelle with essential metabolic functions. Although the FASII fatty acid biosynthesis pathway located in the apicoplast is essential for parasite survival, the cellular effects of FASII disruption in T. gondii had not been examined in detail. Here, we combined light and electron microscopy techniques - including focused ion beam scanning electron microscopy (FIB-SEM) - to characterize the effect of FASII disruption in T. gondii, by treatment with the FASII inhibitor triclosan or by inducible knockdown of the FASII component acyl carrier protein. Morphological analyses showed that FASII disruption prevented cytokinesis completion in T. gondii tachyzoites, leading to the formation of large masses of 'tethered' daughter cells. FIB-SEM showed that tethered daughters had a mature basal complex, but a defect in new membrane addition between daughters resulted in incomplete pellicle formation. Addition of exogenous fatty acids to medium suppressed the formation of tethered daughter cells and supports the notion that FASII is essential to generate lipid substrates required for the final step of parasite division.

  16. Antimicrobial efficacy of emulsified essential oil components against weak acid-adapted spoilage yeasts in clear and cloudy apple juice.

    PubMed

    Loeffler, Myriam; Beiser, Sophia; Suriyarak, Sarisa; Gibis, Monika; Weiss, Jochen

    2014-08-01

    The antimicrobial activity of oil-in-water emulsions containing dual combinations of the essential oil components cinnamaldehyde, perillaldehyde, and citral was examined against two acid-resistant yeast strains (Zygosaccharomyces bailii) in beverage systems composed of diluted clear or cloudy apple juice and in a Sabouraud dextrose broth model. Antimicrobial properties of an encapsulated oil-in-water emulsion and of essential oil components dissolved in 10% dimethyl sulfoxide were compared using plate counts and turbidity measurements. Growth curves were modulated to qualitatively assess differences in antimicrobial efficacy. The impact of the presence of a beverage emulsion without essential oils (unloaded; 5% oil and 1% modified starch, pH 3.0) on the antimicrobial efficacy also was investigated. Dual combinations of essential oil components were sufficient to completely inhibit and/or kill yeast cells in diluted apple juice and Sabouraud dextrose broth systems at very low concentrations (100 to 200 μg/ml). However, the combination of perillaldehyde and citral had the weakest antimicrobial effect; a concentration of 400 μg/ml was necessary to prevent yeast growth in beverages, and up to 800 μg/ml was required in systems to which an unloaded emulsion had been added. The antimicrobial activity of essential oil components did not differ in diluted clear and cloudy apple juices and was not affected by being added in emulsified form or dissolved in dimethyl sulfoxide as long as there was no unloaded emulsion also present. These results indicate that formulations of essential oil combinations encapsulated together in emulsions are highly effective for inhibiting and/or killing microorganisms in real beverage systems.

  17. Increasing intake of essential fatty acids from milk replacer benefits performance, immune responses, and health of preweaned Holstein calves.

    PubMed

    Garcia, M; Shin, J H; Schlaefli, A; Greco, L F; Maunsell, F P; Thatcher, W W; Santos, J E P; Staples, C R

    2015-01-01

    The objective was to evaluate the effect of feeding increasing amounts of essential fatty acids (FA) in milk replacer (MR) during the first 60 d of life on growth, health, and immunity of Holstein calves. Calves were born from dams fed low concentrations of total and essential FA during the lasT2 mo of pregnancy. Newborn calves were blocked by sex and parity of the dam and assigned randomly to receive 1 of 4 MR treatments (T). Hydrogenated coconut oil and soybean oil were mixed with emulsifier and commercial MR powder to prepare the following 4 MR containing 0.119 and 0.007 (T1), 0.187 and 0.017 (T2), 0.321 and 0.036 (T3), and 0.593 and 0.076 (T4) g of intake per kg of metabolic body weight (BW(0.75)) of linoleic acid and α-linolenic acid, respectively. At 30 d of life, concentrations of essential FA (linoleic acid and α-linolenic acid) in liver increased, whereas concentrations of C12:0, C14:0, C16:0, and C20:3n-9 decreased linearly with increasing intake of essential FA. Body weight gain and feed efficiency were optimized when male calves consumed T2, whereas gain by female calves tended to increase linearly with increasing intake of essential FA during the first 30 d of age. However, these responses to treatment were not maintained after initiation of concentrate feeding at 31 d of life. Over the 60-d preweaning period, wither and hip heights were improved in both sexes as intake of essential FA increased up to T3. Some measures of health and immunity were affected by replacing some coconut oil with soybean oil. Severity of diarrhea tended to decrease linearly; plasma concentrations of haptoglobin during diarrhea were lower in T2, T3, and T4; phagocytosis by blood neutrophils tended to peak for calves fed T2; in vitro proliferation of stimulated blood lymphocytes was greater for calves fed T2; in vitro stimulated blood cells produced more IFN-γ (up to T3 for males and T2 for females), concentrations of serum IgG against ovalbumin injections were increased in

  18. n-3 Essential fatty acids decrease weight gain in genetically obese mice.

    PubMed

    Cunnane, S C; McAdoo, K R; Horrobin, D F

    1986-07-01

    1. Lean (ln/ln) and obese (ob/ob) mice were given diets containing a fat source of 100 g evening primrose (Oenothera biennis) oil (fatty acids 18:2n-6, 18:3n-6; EPO) or 100 g cod liver oil (20:5n-3, 22:6n-3; CLO)/kg diet. 2. Weight gain was lower in the ob/ob mice fed on CLO, an effect unrelated to food intake. 3. In the ob/ob mice fed on CLO, thromboxane synthesis by clotting platelets was reduced compared with that in ob/ob mice fed on EPO. 4. The ob/ob CLO-fed mice had lower arachidonic acid but higher levels of n-3 fatty acids in liver, brown adipose tissue and white adipose tissue. 5. The n-3 fatty acids in CLO therefore replaced the n-6 fatty acids in tissue lipids and reduced synthesis of '2 series' prostaglandins in addition to causing lower weight gain in the CLO-fed ob/ob mice.

  19. Urea, glycolic acid, and glycerol in an organic residue produced by ultraviolet irradiation of interstellar/pre-cometary ice analogs.

    PubMed

    Nuevo, Michel; Bredehöft, Jan Hendrik; Meierhenrich, Uwe J; d'Hendecourt, Louis; Thiemann, Wolfram H-P

    2010-03-01

    More than 50 stable organic molecules have been detected in the interstellar medium (ISM), from ground-based and onboard-satellite astronomical observations, in the gas and solid phases. Some of these organics may be prebiotic compounds that were delivered to early Earth by comets and meteorites and may have triggered the first chemical reactions involved in the origin of life. Ultraviolet irradiation of ices simulating photoprocesses of cold solid matter in astrophysical environments have shown that photochemistry can lead to the formation of amino acids and related compounds. In this work, we experimentally searched for other organic molecules of prebiotic interest, namely, oxidized acid labile compounds. In a setup that simulates conditions relevant to the ISM and Solar System icy bodies such as comets, a condensed CH(3)OH:NH(3) = 1:1 ice mixture was UV irradiated at approximately 80 K. The molecular constituents of the nonvolatile organic residue that remained at room temperature were separated by capillary gas chromatography and identified by mass spectrometry. Urea, glycolic acid, and glycerol were detected in this residue, as well as hydroxyacetamide, glycerolic acid, and glycerol amide. These organics are interesting target molecules to be searched for in space. Finally, tentative mechanisms of formation for these compounds under interstellar/pre-cometary conditions are proposed.

  20. Functional properties of whey, whey components, and essential amino acids: mechanisms underlying health benefits for active people (review).

    PubMed

    Ha, Ewan; Zemel, Michael B

    2003-05-01

    Whey proteins and amino acid supplements have a strong position in the sports nutrition market based on the purported quality of proteins and amino acids they provide. Recent studies employing stable isotope methodology demonstrate the ability of whey proteins or amino acid mixtures of similar composition to promote whole body and muscle protein synthesis. Other developing avenues of research explore health benefits of whey that extend beyond protein and basic nutrition. Many bioactive components derived from whey are under study for their ability to offer specific health benefits. These functions are being investigated predominantly in tissue culture systems and animal models. The capacity of these compounds to modulate adiposity, and to enhance immune function and anti-oxidant activity presents new applications potentially suited to the needs of those individuals with active lifestyles. This paper will review the recent literature that describes functional properties of essential amino acids, whey proteins, whey-derived minerals and other compounds and the mechanisms by which they may confer benefits to active people in the context that exercise is a form of metabolic stress. The response to this stress can be positive, as with the accretion of more muscle and improved functionality or greater strength. However, overall benefits may be compromised if immune function or general health is challenged in response to the stress. From a mechanistic standpoint, whey proteins, their composite amino acids, and/or associated compounds may be able to provide substrate and bioactive components to extend the overall benefits of physical activity.

  1. Technical note: Methodological and feed factors affecting prediction of ruminal degradability and intestinal digestibility of essential amino acids.

    PubMed

    White, Robin R; Kononoff, Paul J; Firkins, Jeffrey L

    2017-03-01

    We hypothesized that ruminal degradability of essential AA (EAA) and the intestinal digestibility of the ruminally undegraded EAA residue in feeds could be evaluated in a meta-analysis. The objective was to characterize methodological factors for ruminal incubation (time of incubation of feed in situ) and method of simulating digestion of the ruminally undegraded AA (incubation of residue in digestive enzymes in vitro or in mobile bags inserted into the duodenum). To increase numbers of observations, feeds were categorized before ANOVA. An approach is described to predict differential ruminal degradability (or undegradability) of individual EAA by normalizing them as a proportion of total AA (TAA) degradability (undegradability) and similarly to normalize the intestinal digestibility of EAA using TAA. Interaction of feed category with individual EAA justifies future studies with a broader range of feeds and more replication within feed to bolster this approach. With broader data, the approach to normalize EAA as a proportion of TAA should allow a better defined EAA library to be integrated with more robust CP databases (that can be updated with specific feed information from more routine laboratory analyses) in dairy supply-requirement models.

  2. Pulsed EPR Determination of Water Accessibility to Spin-Labeled Amino Acid Residues in LHCIIb

    PubMed Central

    Volkov, A.; Dockter, C.; Bund, T.; Paulsen, H.; Jeschke, G.

    2009-01-01

    Membrane proteins reside in a structured environment in which some of their residues are accessible to water, some are in contact with alkyl chains of lipid molecules, and some are buried in the protein. Water accessibility of residues may change during folding or function-related structural dynamics. Several techniques based on the combination of pulsed electron paramagnetic resonance (EPR) with site-directed spin labeling can be used to quantify such water accessibility. Accessibility parameters for different residues in major plant light-harvesting complex IIb are determined by electron spin echo envelope modulation spectroscopy in the presence of deuterated water, deuterium contrast in transversal relaxation rates, analysis of longitudinal relaxation rates, and line shape analysis of electron-spin-echo-detected EPR spectra as well as by the conventional techniques of measuring the maximum hyperfine splitting and progressive saturation in continuous-wave EPR. Systematic comparison of these parameters allows for a more detailed characterization of the environment of the spin-labeled residues. These techniques are applicable independently of protein size and require ∼10–20 nmol of singly spin-labeled protein per sample. For a residue close to the N-terminus, in a domain unresolved in the existing x-ray structures of light-harvesting complex IIb, all methods indicate high water accessibility. PMID:19186148

  3. Influence of shear force on floc properties and residual aluminum in humic acid treatment by nano-Al₁₃.

    PubMed

    Xu, Weiying; Gao, Baoyu; Du, Bin; Xu, Zhenghe; Zhang, Yongfang; Wei, Dong

    2014-04-30

    The impacts of various shear forces on floc sizes and structures in humic acid coagulations by polyaluminum chloride (PACl) and nano-Al13 were comparatively studied in this paper. The dynamic floc size was monitored by use of a laser diffraction particle sizing device. The floc structure was evaluated in terms of fractal dimension, analyzed by small-angle laser light scattering (SALLS). The effect of increased shear rate on residual Al of the coagulation effluents was then analyzed on the basis of different floc characteristics generated under various shear conditions. The results showed that floc size decreased with the increasing shear rate for both Al13 and PACl. Besides, floc strength and re-formation ability were also weakened by the enhanced shear force. Al13 resulted in small, strong and better recoverable flocs than PACl and moreover, in the shear range of 100-300 revolution per minute (rpm) (G=40.7-178.3s(-1)), the characteristics of HA-Al13 flocs displayed smaller scale changes than those of HA-PACl flocs. The results of residual Al measurements proved that with shear increased, the residual Al increased continuously but Al13 presented less sensitivity to the varying shear forces. PACl contributed higher residual Al than Al13 under the same shear condition.

  4. Kinetic and mutagenic evidence for the role of histidine residues in the Lycopersicon esculentum 1-aminocyclopropane-1-carboxylic acid oxidase.

    PubMed

    Tayeh, M A; Howe, D L; Salleh, H M; Sheflyan, G Y; Son, J K; Woodard, R W

    1999-01-01

    The ACCO gene from Lycopersicon esculentum (tomato) has been cloned into the expression vector PT7-7. The highly expressed protein was recovered in the form of inclusion bodies. ACCO is inactivated by diethyl pyrocarbonate (DEPC) with a second-order rate constant of 170 M(-1) min(-1). The pH-inactivation rate data imply the involvement of an amino acid residue with a pK value of 6.05. The difference UV spectrum of the the DEPC-inactivated versus native ACCO showed a single peak at 242 nm indicating the modification of histidine residues. The inactivation was reversed by the addition of hydroxylamine to the DEPC-inactivated ACCO. Substrate/cofactor protection studies indicate that both iron and ACC bind near the active site, which contains histidine residues. Four histidines of ACCO were individually mutated to alanine and glycine. H39A is catalytically active, while H177A, H177G, H211A, H211G, H234A, and H234G are basically inactive. The results indicate that histidine residues 177, 211, and 234 may serve as ligands for the active-site iron of ACCO and/or may play some important structural or catalytic role.

  5. Essential role for retinoic acid in the promotion of CD4+ T cell effector responses via retinoic acid receptor alpha

    PubMed Central

    Hall, J.A.; Cannons, J.L.; Grainger, J.R.; Santos, L.M. Dos; Hand, T.W.; Naik, S.; Wohlfert, E.A.; Chou, D.B.; Oldenhove, G.; Robinson, M.; Grigg, M.E.; Kastenmayer, R.; Schwartzberg, P.L.; Belkaid, Y.

    2012-01-01

    SUMMARY Vitamin A and its metabolite, retinoic acid (RA), have recently been implicated in the regulation of immune homeostasis via the peripheral induction of regulatory T cells. Here we show that RA is also required to elicit proinflammatory CD4+ helper T cell responses to infection and mucosal vaccination. Retinoic acid receptor alpha (RARα) is the critical mediator of these effects. Strikingly, antagonism of RAR signaling and deficiency in RARα(Rara−/−) results in a cell autonomous CD4+ T cell activation defect. Altogether, these findings reveal a fundamental role for the RA/RARα axis in the development of both regulatory and inflammatory arms of adaptive immunity and establish nutritional status as a broad regulator of adaptive T cell responses. PMID:21419664

  6. Heart-type Fatty Acid-binding Protein Is Essential for Efficient Brown Adipose Tissue Fatty Acid Oxidation and Cold Tolerance*

    PubMed Central

    Vergnes, Laurent; Chin, Robert; Young, Stephen G.; Reue, Karen

    2011-01-01

    Brown adipose tissue has a central role in thermogenesis to maintain body temperature through energy dissipation in small mammals and has recently been verified to function in adult humans as well. Here, we demonstrate that the heart-type fatty acid-binding protein, FABP3, is essential for cold tolerance and efficient fatty acid oxidation in mouse brown adipose tissue, despite the abundant expression of adipose-type fatty acid-binding protein, FABP4 (also known as aP2). Fabp3−/− mice exhibit extreme cold sensitivity despite induction of uncoupling and oxidative genes and hydrolysis of brown adipose tissue lipid stores. However, using FABP3 gain- and loss-of-function approaches in brown adipocytes, we detected a correlation between FABP3 levels and the utilization of exogenous fatty acids. Thus, Fabp3−/− brown adipocytes fail to oxidize exogenously supplied fatty acids, whereas enhanced Fabp3 expression promotes more efficient oxidation. These results suggest that FABP3 levels are a determinant of fatty acid oxidation efficiency by brown adipose tissue and that FABP3 represents a potential target for modulation of energy dissipation. PMID:21044951

  7. Bioavailability of omega-3 essential fatty acids from perilla seed oil.

    PubMed

    Kurowska, E M; Dresser, G K; Deutsch, L; Vachon, D; Khalil, W

    2003-03-01

    Increased dietary intake of fish oil omega-3 fatty acids, eicosapentanoic acid and docosohexanoic acid, and their precursor, alpha-linolenic acid (ALA), is associated with various health benefits. Enteric-coating (Entrox), which improves stability of omega-3 capsules, has been shown to facilitate fish oil absorption after chronic treatment. To assess the effect of Entrox coating on the short-term bioavailability of ALA administered in the form of ALA-rich Perilla seed oil, 12 healthy subjects (6 males and 6 females) received in a random order Entrox-coated and non-coated ALA formulations, each as a single 6g dose separated by a 3-week washout period. Measurements of plasma ALA concentrations from 0 to 24h showed no difference in ALA pharmacokinetics between the two formulations. However, significantly greater increases in plasma ALA levels from baseline to 24h were observed after ingestion of Entrox vs. non-coated product, suggesting a possible benefit of Entrox with long-term treatment.

  8. Dry heat popping of amaranth seed might damage some of its essential amino acids.

    PubMed

    Tovar, L R; Brito, E; Takahashi, T; Miyazawa, T; Soriano, J; Fujimoto, K

    1989-12-01

    Amaranth was a major crop among the Aztecs. In Mexico the seed is popped and eaten with brown sugar. The crude protein content of the seed is 14 +/- 2% but its contents of lysine and tryptophan are 6.2 and 1.6 g/16 g N respectively. We developed a popping method based on a fluid bed system (FBS) whereas the traditional method (TM) is just to pop the seeds manually in a hot plate. Assays carried out were evaluation of racemization of the amaranth protein due to heat treatment, amino acid composition of the raw and heat treated seeds and a biological experiment testing whether leucine was the most limiting amino acid of amaranth protein. Male rats were fed both popped amaranths and roasted amaranth. Parboiled amaranth and casein were controls. The results were: (a) Lys, Arg and Cys were damaged in the heat treated seeds; (b) Asp, Met, Glu, Ala and Phe were racemized in that decreasing order in the seeds popped and roasted by the TM; (c) the estimated net protein retention (NPR) and estimated net protein utilization (NPU) of popped amaranths by either method were not different, but were lower than for the parboiled amaranth. The parboiled amaranth was not different from casein; (d) Leu was not the most limiting amino acid in any of the amaranth seeds tested. After Lys, sulfur amino acids appear to be the next most limiting in severely heat treated amaranth. The FBS seems to be a promising method for popping amaranth at industrial level.

  9. Reversible receptor methylation is essential for normal chemotaxis of Escherichia coli in gradients of aspartic acid.

    PubMed Central

    Weis, R M; Koshland, D E

    1988-01-01

    The chemotaxis of wild-type cells of Escherichia coli and double mutants lacking the methyltransferase and the methylesterase activities of the receptor modification system has been compared in spatial gradients of aspartic acid. Previous studies showing that a chemotactic response can be observed for the mutant raised questions about the role of methylation in the bacterial memory. To clarify the role of methylation, the redistribution of bacteria in stabilized defined gradients of aspartic acid was monitored by light scattering. There was no redistribution of the mutant cells in nonsaturating gradients of aspartic acid, but over the same range these mutant bacteria were observed to respond and to adapt during tethering experiments. In large saturating gradients of aspartate, slight movement of the mutant up the gradient was observed. These results show that dynamic receptor methylation is required for the chemotactic response to gentle gradients of aspartic acid and that methylation resets to zero and is part of the normal wild-type memory. There are certain gradients, however, in which the methylation-deficient mutants show chemotactic ability, thus explaining the apparent anomaly. Images PMID:2829179

  10. [Correlation between the output and composition of essential oil and the level of salicylic acid in mint plants at different ontogenetic stages].

    PubMed

    Shelepova, O V; Kondrat'eva, V V; Voronkova, T V; Olekhnovich, L S

    2013-01-01

    Dynamic changes in the content of acetylsalicylic acid and the output and qualitative composition of essential oil have been studied in mint plants (Mentha spicata L. and cultivar Medichka) during their ontogenesis with allowance for changes in weather conditions. Ontogenetic changes in the level of acetylsalicylic acid in leaf tissues are found to be similar in both cv. Medichka and M. spicata. In the case of cv. Medichka, this change is connected with the dynamics of the production and the qualitative composition of essential oil; in the case of M. spicata, this connection is less expressed. The role of acetylsalicylic acid and essential oil in plant adaptation to the environment is discussed.

  11. Essential fatty acid supplementation during lactation is required to maximize the subsequent reproductive performance of the modern sow.

    PubMed

    Rosero, David S; Boyd, R Dean; McCulley, Mark; Odle, Jack; van Heugten, Eric

    2016-05-01

    This study was conducted to investigate the effects of supplemental essential fatty acids (EFA) on sow reproductive efficiency and to estimate the concentrations of EFA required by the lactating sow for maximum subsequent reproduction. Data were collected on 480 sows (PIC Camborough) balanced by parity, with 241 and 239 sows representing Parity 1, and 3-5 (P3+), respectively. Sows were assigned randomly, within parity, to a 3 × 3 factorial arrangement plus a control diet without added lipids. Factors included linoleic (2.1%, 2.7%, and 3.3%) and α-linolenic acid (0.15%, 0.30%, and 0.45%), obtained by adding 4% of different mixtures of canola, corn and flaxseed oils to diets. Diets were corn-soybean meal based with 12% wheat middlings. The benefits of supplemental EFA were more evident for the subsequent reproduction of mature P3+ sows. For these sows, supplemental α-linolenic acid improved the proportion of sows that farrowed relative to sows weaned (linear P=0.080; 82.8, 80.5, and 92.8% for sows fed 0.15%, 0.30%, and 0.45% α-linolenic acid, respectively). In addition, supplemental linoleic acid, fed to Parity 1 and P3+ sows, tended to increase subsequent litter size (linear P=0.074; 13.2, 13.8 and 14.0 total pigs born for 2.1%, 2.7% and 3.3% linoleic acid, respectively). These results demonstrate that a minimum dietary intake of both α-linolenic and linoleic acid is required for the modern lactating sow to achieve a maximum reproductive outcome through multiple mechanisms that include rapid return to estrus, increased maintenance of pregnancy and improved subsequent litter size.

  12. A Review: Supplementation of Foods with Essential Fatty Acids-Can It Turn a Breeze without Further Ado?

    PubMed

    Ganesh, Vijayalakshmi; Hettiarachchy, Navam S

    2016-07-03

    This paper focuses on the critical aspects of supplementation of foods with essential fatty acids (EFAs), the need, health benefits of supplementation and the constraints of the process. Current trend of supplementation of foods with EFAs has been gaining momentum and more research pioneers due to the health benefits in par with the direct intake of EFA supplements. Technologies including encapsulation, nanotechnology, molecular complexing, genetic engineering and more emerging means, hold promise to food supplementation with EFAs. Food trials with adoption of various technologies, studies of bioavailability and health benefits are still underway and crucial before EFA supplementation in foods can hit the market on a global scale.

  13. Identification of functionally important amino acid residues in the mitochondria targeting sequence of Hepatitis B virus X protein

    SciTech Connect

    Li, Sai Kam; Ho, Sai Fan; Tsui, Kwok Wing; Fung, Kwok Pui; Waye, M.Y. Mary

    2008-11-10

    Chronic hepatitis B virus (HBV) infection has been strongly associated with hepatocellular carcinoma (HCC) and the X protein (HBx) is thought to mediate the cellular changes associated with carcinogenesis. Recently, isolation of the hepatitis B virus integrants from HCC tissue by others have established the fact that the X gene is often truncated at its C-terminus. Expression of the GFP fusion proteins of HBx and its truncation mutants with a GFP tag in human liver cell-lines in this study revealed that the C-terminus of HBx is indispensable for its specific localization in the mitochondria. A crucial region of seven amino acids at the C-terminus has been mapped out in which the cysteine residue at position 115 serves as the most important residue for the subcellular localization. When cysteine 115 of HBx is mutated to alanine the mitochondria targeting property of HBx is abrogated.

  14. A facile route to preparation of high purity nanoporous silica from acid-leached residue of serpentine.

    PubMed

    Bai, Penn; Sharratt, Paul; Yeo, Tze Yuen; Bu, Jie

    2014-09-01

    As the current cost of mineral carbonation is too high for an economically viable industrial process, it is desirable to produce value-added products from CO2 mineralization process. In this work, a facile and cost-effective process was developed for the production of high purity SiO2 from acid-leached serpentine residue. The Si extraction rate is fast even under ambient conditions due to the highly defective structure of the residue. The reaction kinetics were studied and it was found that the Si extraction rate was under a combination of chemical reaction control and film diffusion control. The SiO2 sample prepared has high purity with a nanoporous structure, which renders it a potential candidate for applications such as an adsorbent and a catalyst support.

  15. Effects of particle size and acid addition on the remediation of chromite ore processing residue using ferrous sulfate.

    PubMed

    Jagupilla, Santhi Chandra; Moon, Deok Hyun; Wazne, Mahmoud; Christodoulatos, Christos; Kim, Min Gyu

    2009-08-30

    A bench-scale treatability study was conducted to assess the effects of particle size and acid addition on the remediation of chromite ore processing residue (COPR) using ferrous sulfate. The remediation scheme entailed the chemical reduction of hexavalent chromium [Cr(VI)] and the mitigation of swell potential. Leaching tests and the EQ3/6 geochemical model were used to estimate the acid dosage required to destabilize Cr(VI)-bearing and swell-causing minerals. The model predicted greater acid dosage than that estimated from the batch leaching tests. This indicated that mass transfer limitation may be playing a significant role in impeding the dissolution of COPR minerals following acid addition and hence hindering the remediation of COPR. Cr(VI) concentrations determined by alkaline digestion for the treated samples were less than the current NJDEP standard. However, Cr(VI) concentrations measured by X-ray absorption near edge structure (XANES) were greater than those measured by alkaline digestion. Greater Cr(VI) percentages were reduced for acid pretreated and also for smaller particle size COPR samples. Upon treatment, brownmillerite content was greatly reduced for the acid pretreated samples. Conversely, ettringite, a swell-causing mineral, was not observed in the treated COPR.

  16. Mutant characterization and in vivo conditional repression identify aromatic amino acid biosynthesis to be essential for Aspergillus fumigatus virulence

    PubMed Central

    Sasse, Anna; Hamer, Stefanie N; Amich, Jorge; Binder, Jasmin; Krappmann, Sven

    2016-01-01

    Pathogenicity of the saprobe Aspergillus fumigatus strictly depends on nutrient acquisition during infection, as fungal growth determines colonisation and invasion of a susceptible host. Primary metabolism has to be considered as a valid target for antimycotic therapy, based on the fact that several fungal anabolic pathways are not conserved in higher eukaryotes. To test whether fungal proliferation during invasive aspergillosis relies on endogenous biosynthesis of aromatic amino acids, defined auxotrophic mutants of A. fumigatus were generated and assessed for their infectious capacities in neutropenic mice and found to be strongly attenuated in virulence. Moreover, essentiality of the complete biosynthetic pathway could be demonstrated, corroborated by conditional gene expression in infected animals and inhibitor studies. This brief report not only validates the aromatic amino acid biosynthesis pathway of A. fumigatus to be a promising antifungal target but furthermore demonstrates feasibility of conditional gene expression in a murine infection model of aspergillosis. PMID:26605426

  17. Determination by systematic deletion of the amino acids essential for catalysis by ricin A chain.

    PubMed Central

    Morris, K N; Wool, I G

    1992-01-01

    The A chain of ricin is a RNA N-glycosidase that inactivates ribosomes by depurination of a single adenosine in 28S rRNA. Of the 267 amino acids in the protein, 222 (83%) could be deleted from one or another of 74 mutants without loss of the capacity of the protein to recognize a single nucleotide from among the 7000 in ribosomes or to catalyze hydrolysis. Images PMID:1594586

  18. Energy vs. essential fatty acids: what do scallop larvae (Argopecten purpuratus) need most?

    PubMed

    Nevejan, Nancy; Saez, Iris; Gajardo, Gonzalo; Sorgeloos, Patrick

    2003-04-01

    Larvae of the Chilean-Peruvian scallop Argopecten purpuratus were fed a Dunaliella tertiolecta diet (Dun-diet) supplemented with lipid emulsions, rich in 20:5n-3 (EmEPA), 22:6n-3 (EmDHA) or in saturated fatty acids (EmCOCO). A mixed algal diet of Isochrysis galbana (T-iso) and Chaetoceros neogracile served as a positive control (St-diet). Lipid supplementation to the Dun-diet improved the larval growth and increased the percentage of eyed larvae significantly, compared to the non-supplemented Dun-diet because of the extra energy supplied and not because of its fatty acid composition. No significant differences were observed between supplementation with EmEPA, EmDHA or EmCOCO. A mixture of 20% EmEPA+20% EmDHA (40% EmHUFA) was more efficient in raising the total lipid content in larvae than 40% EmCOCO. Both emulsions increased the triacylglycerol content in larvae compared to the non-supplemented Dun-diet. The best result, however, was obtained with the St-diet, probably because of a more suitable 18:2n-6/18:3n-3 ratio and a higher level of arachidonic acid. A positive relationship between the 18:2n-6/18:3n-3 ratio and the larval performance was found. No significant difference was observed in post-settlement larval size or percentage of metamorphosed larvae between the St-diet and the St-diet supplemented with 20% EmHUFA or 20% EmCOCO. The metamorphosed larvae had a constant DHA/EPA ratio of 3.7, independent from the diet, which suggested a metabolic control of the two fatty acids and a species-dependency of the ratio.

  19. Predominant information quality scheme for the essential amino acids: an information-theoretical analysis.

    PubMed

    Esquivel, Rodolfo O; Molina-Espíritu, Moyocoyani; López-Rosa, Sheila; Soriano-Correa, Catalina; Barrientos-Salcedo, Carolina; Kohout, Miroslav; Dehesa, Jesús S

    2015-08-24

    In this work we undertake a pioneer information-theoretical analysis of 18 selected amino acids extracted from a natural protein, bacteriorhodopsin (1C3W). The conformational structures of each amino acid are analyzed by use of various quantum chemistry methodologies at high levels of theory: HF, M062X and CISD(Full). The Shannon entropy, Fisher information and disequilibrium are determined to grasp the spatial spreading features of delocalizability, order and uniformity of the optimized structures. These three entropic measures uniquely characterize all amino acids through a predominant information-theoretic quality scheme (PIQS), which gathers all chemical families by means of three major spreading features: delocalization, narrowness and uniformity. This scheme recognizes four major chemical families: aliphatic (delocalized), aromatic (delocalized), electro-attractive (narrowed) and tiny (uniform). All chemical families recognized by the existing energy-based classifications are embraced by this entropic scheme. Finally, novel chemical patterns are shown in the information planes associated with the PIQS entropic measures.

  20. The aspartate-family pathway of plants: linking production of essential amino acids with energy and stress regulation.

    PubMed

    Galili, Gad

    2011-02-01

    The Asp family pathway of plants is highly important from a nutritional standpoint because it leads to the synthesis of the four essential amino acids Lys, Thr, Met and Ile. These amino acids are not synthesized by human and its monogastric livestock and should be supplemented in their diets. Among the Asp-family amino acids, Lys is considered as the nutritionally most important essential amino acid because its level is most limiting in cereal grains, representing the largest source of plant foods and feeds worldwide. Metabolic engineering approaches led to significant increase in Lys level in seeds by enhancing its synthesis and reducing its catabolism. However, results from the model plant Arabidopsis showed that this approach may retard seed germination due to a major negative effect on the levels of a number of TCA cycle metabolites that associate with cellular energy. In the present review, we discuss the regulatory metabolic link of the Asp-family pathway with the TCA cycle and its biological significance upon exposure to stress conditions that cause energy deprivation. In addition, we also discuss how deep understanding of the regulatory metabolic link of the Asp-family pathway with energy and stress regulation can be used to improve Lys level in seeds of important crop species, minimizing the interference with the cellular energy status and plant-stress interaction. This review thus provides an example showing how deep understanding the inter-regulation of metabolism with plant stress physiology can lead to successful nutritional improvements with minimal negative effect on plant growth and response to stressful environments.

  1. ASCORBIC ACID REDUCTION ON RESIDUAL ACTIVE CHLORINE IN POTABLE WATER PRIOR TO HALOCARBOXYLATE DETERMINATION

    EPA Science Inventory

    In studies on the formation of disinfection byproducts (DBPs), it is necessary to scavenge residual active (odxidizing) chlorine in order to fix the chlorination byproducts (such as haloethanoates) at a point in time . Such research projects often have distinct needs from requi...

  2. ASCORBIC ACID REDUCTION OF RESIDUAL ACTIVE CHLORINE IN POTABLE WATER PRIOR TO HALOCARBOXYLATE DETERMINATION

    EPA Science Inventory

    In studies on the formation of disinfection byproducts (DBPs), it is necessary to scavenge residual active (oxidizing) chlorine in order to fix the chlorination byproducts (such as haloethanoates) at a point in time. Thus, methods designed for compliance monitoring are not alway...

  3. 40 CFR 180.155 - 1-Naphthaleneacetic acid; tolerances for residues.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... (CONTINUED) PESTICIDE PROGRAMS TOLERANCES AND EXEMPTIONS FOR PESTICIDE CHEMICAL RESIDUES IN FOOD Specific... ammonium, sodium, or potassium salts, ethyl ester, and acetamide in or on food commodities as follows: Commodity Parts per million Cherry, sweet 0.1 Fruit, pome, group 11 0.15 Olive 0.7 Orange 0.1 Pineapple1...

  4. Analysis of an invariant cofactor-protein interaction in thiamin diphosphate-dependent enzymes by site-directed mutagenesis. Glutamic acid 418 in transketolase is essential for catalysis.

    PubMed

    Wikner, C; Meshalkina, L; Nilsson, U; Nikkola, M; Lindqvist, Y; Sundström, M; Schneider, G

    1994-12-23

    A homologous expression system and a purification protocol for pure, highly active recombinant yeast transketolase have been developed. The invariant transketolase residue Glu418, which forms a hydrogen bond to the N-1' nitrogen atom of the pyrimidine ring of the cofactor thiamin diphosphate has been replaced by glutamine and alanine. Crystallographic analyses of the mutants show that these amino acid substitutions do not induce structural changes beyond the site of mutation. In both cases, the cofactor binds in a manner identical to the wild-type enzyme. Significant differences in the CD spectra of the mutant transketolases compared with the spectrum of wild-type enzyme indicate differences in the electron distribution of the aminopyrimidine ring of the cofactor. The E418Q mutant shows 2% and the E418A mutant shows about 0.1% of the catalytic activity of wild-type enzyme. The affinities of the mutant enzymes for thiamin diphosphate are comparable with wild-type transketolase. The hydrogen bond between the coenzyme and the side chain of Glu418 is thus not required for coenzyme binding but essential for catalytic activity. The results demonstrate the functional importance of this interaction and support the molecular model for cofactor deprotonation, the first step in enzymatic thiamin catalysis.

  5. Uptake of nitric acid, ammonia, and organics in orographic clouds: mass spectrometric analyses of droplet residual and interstitial aerosol particles

    NASA Astrophysics Data System (ADS)

    Schneider, Johannes; Mertes, Stephan; van Pinxteren, Dominik; Herrmann, Hartmut; Borrmann, Stephan

    2017-01-01

    Concurrent in situ analyses of interstitial aerosol and cloud droplet residues have been conducted at the Schmücke mountain site during the Hill Cap Cloud Thuringia campaign in central Germany in September and October 2010. Cloud droplets were sampled from warm clouds (temperatures between -3 and +16 °C) by a counterflow virtual impactor and the submicron-sized residues were analyzed by a compact time-of-flight aerosol mass spectrometer (C-ToF-AMS), while the interstitial aerosol composition was measured by an high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS). During cloud-free periods, the submicron out-of-cloud aerosol was analyzed using both instruments, allowing for intercomparison between the two instruments. Further instrumentation included black carbon measurements and optical particle counters for the aerosol particles as well as optical sizing instrumentation for the cloud droplets. The results show that, under cloud conditions, on average 85 % of the submicron aerosol mass partitioned into the cloud liquid phase. Scavenging efficiencies of nitrate, ammonium, sulfate, and organics ranged between 60 and 100 %, with nitrate having, in general, the highest values. For black carbon, the scavenging efficiency was markedly lower (about 24 %). The nitrate and ammonium mass fractions were found to be markedly enhanced in cloud residues, indicating uptake of gaseous nitric acid and ammonia into the aqueous phase. This effect was found to be temperature dependent: at lower temperatures, the nitrate and ammonium mass fractions in the residues were higher. Also, the oxidation state of the organic matter in cloud residues was found to be temperature dependent: the O : C ratio was lower at higher temperatures. A possible explanation for this observation is a more effective uptake and/or higher concentrations of low-oxidized water-soluble volatile organic compounds, possibly of biogenic origin, at higher temperatures. Organic nitrates were observed

  6. Dynamic HypA zinc site is essential for acid viability and proper urease maturation in Helicobacter pylori

    PubMed Central

    Johnson, Ryan C.; Hu, Heidi Q.; Merrell, D. Scott; Maroney, Michael J.

    2015-01-01

    Helicobacter pylori requires urease activity in order to survive in the acid environment of the human stomach. Urease is regulated in part by nickelation, a process that requires the HypA protein, which is a putative nickel metallochaperone that is generally associated with hydrogenase maturation. However, in H. pylori, HypA plays a dual role. In addition to an N-terminal nickel binding site, HypA proteins also contain a structural zinc site that is coordinated by two rigorously conserved CXXC sequences, which in H. pylori are flanked by His residues. These structural Zn sites are known to be dynamic, converting from Zn(Cys)4 centers at pH 7.2 to Zn(Cys)2(His)2 centers at pH 6.3 in the presence of Ni(II) ions. In this study, mutant strains of H. pylori that express zinc site variants of the HypA protein are used to show that the structural changes in the zinc site are important for the acid viability of the bacterium, and that a reduction in acid viability in these variants can be traced in large measure to deficient urease activity. This in turn leads to a model that connects the Zn(Cys)4 coordination to urease maturation. PMID:25608738

  7. Modulation in vitro of human natural cytotoxicity, lymphocyte proliferative response to mitogens and cytokine production by essential fatty acids.

    PubMed Central

    Purasiri, P; Mckechnie, A; Heys, S D; Eremin, O

    1997-01-01

    Essential fatty acids (EFA) have been shown in animal studies to have a differential effect on various aspects of immune reactivity. However, there have been few studies in humans. Therefore, we elected to investigate the effects of a variety of EFA [gamma-linolenic acid (GLA), eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA)] in vitro on human blood lymphocyte reactivity, cytokine secretion and natural cytotoxicity. The proliferative response to polyclonal mitogens (phytohaemagglutinin, pokeweed mitogen, concanavalin A), as measured by [3H]thymidine incorporation into newly synthesized lymphocytes, was inhibited (P < 0.05) by all EFAs tested, in a dose-dependent manner (3-15 micrograms/ml). The greatest inhibition of proliferation was caused by EPA and DHA. Similarly, EPA, DHA and GLA significantly reduced cytotoxic activity [expressed as lytic units, using 51 chromium-release assays natural killer (NK) (K562 cells) and lymphokine-activated (LAK) (Daudi cells) cells] (P < 0.05) in a concentration-dependent manner (5-50 micrograms/ml), without affecting cell viability. EPA and DHA exhibited greater suppression than GLA. Furthermore, the inhibition of cell proliferation and suppression of natural cytotoxicity was associated with marked decrease in cytokine [interleukin-1 (IL-1), IL-2, tumour necrosis factor-alpha (TNF-alpha) and interferon-gamma (IFN-gamma)] production in vitro. Our findings demonstrate that EFAs (GLA, EPA, DHA) have the potential to inhibit significantly various aspects of human lymphocyte cell-mediated and humoral immune reactivities. PMID:9415022

  8. Intake of essential fatty acids in Indonesian children: secondary analysis of data from a nationally representative survey.

    PubMed

    Neufingerl, Nicole; Djuwita, Ratna; Otten-Hofman, Anke; Nurdiani, Reisi; Garczarek, Ursula; Sulaeman, Ahmad; Zock, Peter L; Eilander, Ans

    2016-02-28

    Essential fatty acids (EFA) such as α-linolenic acid (ALA) and linoleic acid (LA) are needed for healthy growth and development of children. Worldwide, reliable intake data of EFA are often lacking. The objective of this study was to investigate dietary intake of EFA in Indonesian children. Dietary intake data of 4-12-year-old children (n 45,821) from a nationally representative Indonesian survey were used to estimate median intake and distribution of population fatty acid intake. Missing data on individual fatty acids in the Indonesian food composition table were complemented through chemical analyses of national representative food samples and imputation of data from the US nutrient database. Nutrient adequacy ratios were calculated as a percentage of FAO/WHO intake recommendations. The medians of total fat intake of the children was 26·7 (10th-90th percentile 11·2-40·0) percentage of total daily energy (%E). Intakes of fatty acids were 4·05 (10th-90th percentile 1·83-7·22) %E for total PUFA, 3·36 (10th-90th percentile 1·14-6·29) %E for LA and 0·20 (10th-90th percentile 0·07-0·66) %E for ALA. Median intake of PUFA was 67 % and that of ALA 40 % of the minimum amounts recommended by FAO/WHO. These data indicate that a majority of Indonesian children has intakes of PUFA and specifically ALA that are lower than recommended intake levels. Total fat and LA intakes may be suboptimal for a smaller yet considerable proportion of children. Public health initiatives should provide practical guidelines to promote consumption of PUFA-rich foods.

  9. Preparation of a modified flue gas desulphurization residue and its effect on pot sorghum growth and acidic soil amelioration.

    PubMed

    Shi, Lin; Xu, Peizhi; Xie, Kaizhi; Tang, Shuanhu; Li, Yongli

    2011-09-15

    A modified flue gas desulphurization residue (MFGDR) was prepared and its effects on sorghum growth and acidic soil amelioration were evaluated in this paper. The MFGDR was prepared by calcining a mixture of dry/semi-dry flue gas desulphurization (FGD) residue from a coal-fired power plant, sorted potash feldspar and/or limestone powder. The available nutrients from the MFGDR were determined with 4.91 wt% K(+), 1.15 wt% Mg(2+), 22.4 wt% Ca(2+), 7.01 wt% Si(4+) and 2.07 wt% SO(4)(2-)-S in 0.1 mol L(-1) citric acid solution. Its pH value was held at 9.60 displaying slightly alkaline. The results of sorghum pot growth in both red and crimson acidic soil for 30 days indicated that adding the MFGDR at a dosage of 2 g kg(-1) in total soil weight would increase the growth rate of biomass by 24.3-149% (wet weight basis) and 47.3-157% (dry weight), the stem length and thickness increase by 5.75-22.1% and 4.76-30.9% in contrast with CK treatment for two test cuttings, respectively. The effect on sorghum growth was attributed to the increase of available nutrients, the enhancement of soil pH value and the reduction of aluminum toxicity in acidic soil due to the addition of the MFGDR. The experimental results also suggested that the MFGDR could be effectively used to ameliorate the acidic soil which is widely distributed throughout the southern China.

  10. Simulation of acid hydrolysis of lignocellulosic residues to fermentable sugars for bioethanol production

    NASA Astrophysics Data System (ADS)

    Sidiras, Dimitris

    2012-12-01

    The dilute acid hydrolysis of fir sawdust with sulfuric acid was undertaken in a batch reactor system (autoclave). The experimental data and reaction kinetic analysis indicate that this is a potential process for cellulose and hemicelluloses hydrolysis, due to a rapid hydrolysis reaction for acid concentration 0.045 N at 160-180°C. It was found that significant sugar degradation occurred at these conditions. The optimum conditions gave a yield of 38% total fermentable sugars. The kinetics of dilute acid hydrolysis of cellulose and hemicelluloses (polysaccharides) were simulated using four pseudo-kinetic models. The reaction rate constants were calculated in each case.

  11. Docosahexaenoic acid (DHA): An essential nutrient and a nutraceutical for brain health and diseases.

    PubMed

    Sun, Grace Y; Simonyi, Agnes; Fritsche, Kevin L; Chuang, Dennis Y; Hannink, Mark; Gu, Zezong; Greenlief, C Michael; Yao, Jeffrey K; Lee, James C; Beversdorf, David Q

    2017-03-10

    Docosahexaenoic acid (DHA), a polyunsaturated fatty acid (PUFA) enriched in phospholipids in the brain and retina, is known to play multi-functional roles in brain health and diseases. While arachidonic acid (AA) is released from membrane phospholipids by cytosolic phospholipase A2 (cPLA2), DHA is linked to action of the Ca(2+)-independent iPLA2. DHA undergoes enzymatic conversion by 15-lipoxygenase (Alox 15) to form oxylipins including resolvins and neuroprotectins, which are powerful lipid mediators. DHA can also undergo non-enzymatic conversion by reacting with oxygen free radicals (ROS), which cause the production of 4-hydoxyhexenal (4-HHE), an aldehyde derivative which can form adducts with DNA, proteins and lipids. In studies with both animal models and humans, there is evidence that inadequate intake of maternal n-3 PUFA may lead to aberrant development and function of the central nervous system (CNS). What is less certain is whether consumption of n-3 PUFA is important in maintaining brain health throughout one's life span. Evidence mostly from non-human studies suggests that DHA intake above normal nutritional requirements might modify the risk/course of a number of diseases of the brain. This concept has fueled much of the present interest in DHA research, in particular, in attempts to delineate mechanisms whereby DHA may serve as a nutraceutical and confer neuroprotective effects. Current studies have revealed ability for the oxylipins to regulation of cell redox homeostasis through the Nuclear factor (erythroid-derived 2)-like 2/Antioxidant response element (Nrf2/ARE) anti-oxidant pathway, and impact signaling pathways associated with neurotransmitters, and modulation of neuronal functions involving brain-derived neurotropic factor (BDNF). This review is aimed at describing recent studies elaborating these mechanisms with special regard to aging and Alzheimer's disease, autism spectrum disorder, schizophrenia, traumatic brain injury, and stroke.

  12. A Peculiar Formula of Essential Amino Acids Prevents Rosuvastatin Myopathy in Mice

    PubMed Central

    D'Antona, Giuseppe; Tedesco, Laura; Ruocco, Chiara; Corsetti, Giovanni; Ragni, Maurizio; Fossati, Andrea; Saba, Elisa; Fenaroli, Francesca; Montinaro, Mery; Carruba, Michele O.; Valerio, Alessandra

    2016-01-01

    Abstract Aims: Myopathy, characterized by mitochondrial oxidative stress, occurs in ∼10% of statin-treated patients, and a major risk exists with potent statins such as rosuvastatin (Rvs). We sought to determine whether a peculiar branched-chain amino acid-enriched mixture (BCAAem), found to improve mitochondrial function and reduce oxidative stress in muscle of middle-aged mice, was able to prevent Rvs myopathy. Results: Dietary supplementation of BCAAem was able to prevent the structural and functional alterations of muscle induced by Rvs in young mice. Rvs-increased plasma 3-methylhistidine (a marker of muscular protein degradation) was prevented by BCAAem. This was obtained without changes of Rvs ability to reduce cholesterol and triglyceride levels in blood. Rather, BCAAem promotes de novo protein synthesis and reduces proteolysis in cultured myotubes. Morphological alterations of C2C12 cells induced by statin were counteracted by amino acids, as were the Rvs-increased atrogin-1 mRNA and protein levels. Moreover, BCAAem maintained mitochondrial mass and density and citrate synthase activity in skeletal muscle of Rvs-treated mice beside oxygen consumption and ATP levels in C2C12 cells exposed to statin. Notably, BCAAem assisted Rvs to reduce oxidative stress and to increase the anti-reactive oxygen species (ROS) defense system in skeletal muscle. Innovation and Conclusions: The complex interplay between proteostasis and antioxidant properties may underlie the mechanism by which a specific amino acid formula preserves mitochondrial efficiency and muscle health in Rvs-treated mice. Strategies aimed at promoting protein balance and controlling mitochondrial ROS level may be used as therapeutics for the treatment of muscular diseases involving mitochondrial dysfunction, such as statin myopathy. Antioxid. Redox Signal. 25, 595–608. PMID:27245589

  13. Maintenance of essential amino acid synthesis pathways in the Blattabacterium cuenoti symbiont of a wood-feeding cockroach.

    PubMed

    Tokuda, Gaku; Elbourne, Liam D H; Kinjo, Yukihiro; Saitoh, Seikoh; Sabree, Zakee; Hojo, Masaru; Yamada, Akinori; Hayashi, Yoshinobu; Shigenobu, Shuji; Bandi, Claudio; Paulsen, Ian T; Watanabe, Hirofumi; Lo, Nathan

    2013-06-23

    In addition to harbouring intestinal symbionts, some animal species also possess intracellular symbiotic microbes. The relative contributions of gut-resident and intracellular symbionts to host metabolism, and how they coevolve are not well understood. Cockroaches and the termite Mastotermes darwiniensis present a unique opportunity to examine the evolution of spatially separated symbionts, as they harbour gut symbionts and the intracellular symbiont Blattabacterium cuenoti. The genomes of B. cuenoti from M. darwiniensis and the social wood-feeding cockroach Cryptocercus punctulatus are each missing most of the pathways for the synthesis of essential amino acids found in the genomes of relatives from non-wood-feeding hosts. Hypotheses to explain this pathway degradation include: (i) feeding on microbes present in rotting wood by ancestral hosts; (ii) the evolution of high-fidelity transfer of gut microbes via social behaviour. To test these hypotheses, we sequenced the B. cuenoti genome of a third wood-feeding species, the phylogenetically distant and non-social Panesthia angustipennis. We show that host wood-feeding does not necessarily lead to degradation of essential amino acid synthesis pathways in B. cuenoti, and argue that ancestral high-fidelity transfer of gut microbes best explains their loss in strains from M. darwiniensis and C. punctulatus.

  14. Identification of significant amino acids in multiple transmembrane domains of human transient receptor potential ankyrin 1 (TRPA1) for activation by eudesmol, an oxygenized sesquiterpene in hop essential oil.

    PubMed

    Ohara, Kazuaki; Fukuda, Takafumi; Okada, Hiroyuki; Kitao, Sayoko; Ishida, Yuko; Kato, Kyoko; Takahashi, Chika; Katayama, Mikio; Uchida, Kunitoshi; Tominaga, Makoto

    2015-01-30

    Transient receptor potential ankyrin 1 (TRPA1) is a calcium-permeable non-selective cation channel that is activated by various noxious or irritant substances in nature, including spicy compounds. Many TRPA1 chemical activators have been reported; however, only limited information is available regarding the amino acid residues that contribute to the activation by non-electrophilic activators, whereas activation mechanisms by electrophilic ligands have been well characterized. We used intracellular Ca(2+) measurements and whole-cell patch clamp recordings to show that eudesmol, an oxygenated sesquiterpene present at high concentrations in the essential oil of hop cultivar Hallertau Hersbrucker, could activate human TRPA1. Gradual activation of inward currents with outward rectification by eudesmol was observed in human embryonic kidney-derived 293 cells expressing human TRPA1. This activation was completely blocked by a TRPA1-specific inhibitor, HC03-0031. We identified three critical amino acid residues in human TRPA1 in putative transmembrane domains 3, 4, and 5, namely threonine at 813, tyrosine at 840, and serine at 873, for activation by β-eudesmol in a systematic mutational study. Our results revealed a new TRPA1 activator in hop essential oil and provide a novel insight into mechanisms of human TRPA1 activation by non-electrophilic chemicals.

  15. Identification of Significant Amino Acids in Multiple Transmembrane Domains of Human Transient Receptor Potential Ankyrin 1 (TRPA1) for Activation by Eudesmol, an Oxygenized Sesquiterpene in Hop Essential Oil

    PubMed Central

    Ohara, Kazuaki; Fukuda, Takafumi; Okada, Hiroyuki; Kitao, Sayoko; Ishida, Yuko; Kato, Kyoko; Takahashi, Chika; Katayama, Mikio; Uchida, Kunitoshi; Tominaga, Makoto

    2015-01-01

    Transient receptor potential ankyrin 1 (TRPA1) is a calcium-permeable non-selective cation channel that is activated by various noxious or irritant substances in nature, including spicy compounds. Many TRPA1 chemical activators have been reported; however, only limited information is available regarding the amino acid residues that contribute to the activation by non-electrophilic activators, whereas activation mechanisms by electrophilic ligands have been well characterized. We used intracellular Ca2+ measurements and whole-cell patch clamp recordings to show that eudesmol, an oxygenated sesquiterpene present at high concentrations in the essential oil of hop cultivar Hallertau Hersbrucker, could activate human TRPA1. Gradual activation of inward currents with outward rectification by eudesmol was observed in human embryonic kidney-derived 293 cells expressing human TRPA1. This activation was completely blocked by a TRPA1-specific inhibitor, HC03–0031. We identified three critical amino acid residues in human TRPA1 in putative transmembrane domains 3, 4, and 5, namely threonine at 813, tyrosine at 840, and serine at 873, for activation by β-eudesmol in a systematic mutational study. Our results revealed a new TRPA1 activator in hop essential oil and provide a novel insight into mechanisms of human TRPA1 activation by non-electrophilic chemicals. PMID:25525269

  16. Amino acid residues in the Ler protein critical for derepression of the LEE5 promoter in enteropathogenic E. coli.

    PubMed

    Choi, Su-Mi; Jeong, Jae-Ho; Choy, Hyon E; Shin, Minsang

    2016-08-01

    Enteropathogenic E. coli causes attaching and effacing (A/E) intestinal lesions. The genes involved in the formation of A/E lesions are encoded within a chromosomal island comprising of five major operons, LEE1-5. The global regulator H-NS represses the expression of these operons. Ler, a H-NS homologue, counteracts the H-NS-mediated repression. Using a novel genetic approach, we identified the amino acid residues in Ler that are involved in the interaction with H-NS: I20 and L23 in the C-terminal portion of α-helix 3, and I42 in the following unstructured linker region.

  17. Effect of Coriandrum sativum hydroalcoholic extract and its essential oil on acetic acid- induced acute colitis in rats

    PubMed Central

    Heidari, Bahareh; Sajjadi, Seyed Ebrahim; Minaiyan, Mohsen

    2016-01-01

    Objective: The aim of this study was to determine the protective effects of Coriandrum sativum on acetic acid-inducedcolitis in rats. C. sativum (Coriander) has long been used in Iranian traditional medicine and its use as an anti-inflammatory agent is still common in some herbal formulations. Materials and Methods: Colitis was induced by intra-rectal administration of 2ml acetic acid 4% in fasted male Wistar rats. Treatment was carried out using three increasing doses of extract (250, 500, 1000 mg/kg) and essential oil (0.25, 0.5, 1 ml/kg) of coriander started 2 h before colitis induction and continued for a five-day period. Colon biopsies were taken for weighting, macroscopic scoring of injured tissue, histopathological examination and measuring myeloperoxidase (MPO) activity. Results: Colon weight was decreased in the groups treated with extract (500 and 1000 mg/kg) and essential oil (0.5 ml/kg) compared to the control group. Regarding MPO levels, ulcer severity and area as well as the total colitis index, same results indicating meaningful alleviation of colitis was achieved after treatment with oral extract and essential oil. Conclusion: Since the present experiment was made by oral fractions of coriander thus the resulting effects could be due to both the absorption of the active ingredients and/or the effect of non-absorbable materials on colitis after reaching the colon. In this regard, we propose more toxicological and clinical experiments to warranty its beneficial application in human inflammatory bowel diseases. PMID:27222834

  18. Heat Shock 70-kDa Protein 5 (Hspa5) Is Essential for Pronephros Formation by Mediating Retinoic Acid Signaling*

    PubMed Central

    Shi, Weili; Xu, Gang; Wang, Chengdong; Sperber, Steven M.; Chen, Yonglong; Zhou, Qin; Deng, Yi; Zhao, Hui

    2015-01-01

    Heat shock 70-kDa protein 5 (Hspa5), also known as binding immunoglobulin protein (Bip) or glucose-regulated protein 78 (Grp78), belongs to the heat shock protein 70 kDa family. As a multifunctional protein, it participates in protein folding and calcium homeostasis and serves as an essential regulator of the endoplasmic reticulum (ER) stress response. It has also been implicated in signal transduction by acting as a receptor or co-receptor residing at the plasma membrane. Its function during embryonic development, however, remains largely elusive. In this study, we used morpholino antisense oligonucleotides (MOs) to knock down Hspa5 activity in Xenopus embryos. In Hspa5 morphants, pronephros formation was strongly inhibited with the reduction of pronephric marker genes Lim homeobox protein 1 (lhx1), pax2, and β1 subunit of Na/K-ATPase (atp1b1). Pronephros tissue was induced in vitro by treating animal caps with all-trans-retinoic acid and activin. Depletion of Hspa5 in animal caps, however, blocked the induction of pronephros as well as reduced the expression of retinoic acid (RA)-responsive genes, suggesting that knockdown of Hspa5 attenuated RA signaling. Knockdown of Hspa5 in animal caps resulted in decreased expression of lhx1, a transcription factor directly regulated by RA signaling and essential for pronephros specification. Co-injection of Hspa5MO with lhx1 mRNA partially rescued the phenotype induced by Hspa5MO. These results suggest that the RA-Lhx1 signaling cascade is involved in Hspa5MO-induced pronephros malformation. This study shows that Hspa5, a key regulator of the unfolded protein response, plays an essential role in pronephros formation, which is mediated in part through RA signaling during early embryonic development. PMID:25398881

  19. Structure-Based Mutagenesis of Sulfolobus Turreted Icosahedral Virus B204 Reveals Essential Residues in the Virion-Associated DNA-Packaging ATPase

    PubMed Central

    Dellas, Nikki; Snyder, Jamie C.; Dills, Michael; Nicolay, Sheena J.; Kerchner, Keshia M.; Brumfield, Susan K.; Lawrence, C. Martin

    2015-01-01

    ABSTRACT Sulfolobus turreted icosahedral virus (STIV), an archaeal virus that infects the hyperthermoacidophile Sulfolobus solfataricus, is one of the most well-studied viruses of the domain Archaea. STIV shares structural, morphological, and sequence similarities with viruses from other domains of life, all of which are thought to belong to the same viral lineage. Several of these common features include a conserved coat protein fold, an internal lipid membrane, and a DNA-packaging ATPase. B204 is the ATPase encoded by STIV and is thought to drive packaging of viral DNA during the replication process. Here, we report the crystal structure of B204 along with the biochemical analysis of B204 mutants chosen based on structural information and sequence conservation patterns observed among members of the same viral lineage and the larger FtsK/HerA superfamily to which B204 belongs. Both in vitro ATPase activity assays and transfection assays with mutant forms of B204 confirmed the essentiality of conserved and nonconserved positions. We also have identified two distinct particle morphologies during an STIV infection that differ in the presence or absence of the B204 protein. The biochemical and structural data presented here are not only informative for the STIV replication process but also can be useful in deciphering DNA-packaging mechanisms for other viruses belonging to this lineage. IMPORTANCE STIV is a virus that infects a host from the domain Archaea that replicates in high-temperature, acidic environments. While STIV has many unique features, there exist several striking similarities between this virus and others that replicate in different environments and infect a broad range of hosts from Bacteria and Eukarya. Aside from structural features shared by viruses from this lineage, there exists a significant level of sequence similarity between the ATPase genes carried by these different viruses; this gene encodes an enzyme thought to provide energy that drives

  20. AMINO ACID COMPOSITION AND C-TERMINAL RESIDUES OF ALGAL BILIPROTEINS,

    DTIC Science & Technology

    R-phycoerythrin from Ceramium rubrum and C- phycocyanin from Nostoc nuscorum were obtained in purified form by fractional crystallization, followed by...as amino acids. Alanine was identified as the only C-terminal amino acid of R-phycoerythrin, each molecule of which contained about 12 terminal groups. Serine was identified as the only C-terminal group of C- phycocyanin . (Author)

  1. The selective reaction of methoxyamine with cytidine residues in mammalian initiator transfer ribonucleic acid

    PubMed Central

    Piper, Peter W.; Clark, Brian F.C.

    1974-01-01

    Methoxyamine reacts selectively with tRNA molecules at certain exposed cytosine residues usually located in non base-paired regions of the two dimensional clover leaf structure. Here methoxyamine is used for the first time in a study of a mammalian tRNA structure. One of the sequence abnormalities of myeloma initiator tRNA is a cytosine instead of the usual uracil immediately preceding the anticodon. A study of the reaction of the cytosine residues with methoxyamine indicates that the accessibility of bases to chemical reagents in the anticodon loop of this mammalian initiator tRNA is very similar to that observed for the bacterial initiator tRNA. Images PMID:10793658

  2. Effects of Lactic Acid Bacteria on Residual Nitrite in a Summer Style Sausage.

    DTIC Science & Technology

    1984-01-01

    Lactobacillus leichmannii, Streptococcus faecalis, and several atypical lactobacilli isolated from fresh beef and mutton reduced 200-1000 ppm nitrite...faecalis and an atypical lactobacillus isolated from beef) showed abilities to reduce pH and residual nitrite to levels similar to L. plantarum and P...Leuconostoc mesenteroides reduced nitrite at a faster rate than either Lactobacillus plantarum or Lactobacillus viridescens, while Lactobacillus

  3. Stabile Chlorine Isotope Study of Martian Shergottites and Nakhlites; Whole Rock and Acid Leachates and Residues

    NASA Technical Reports Server (NTRS)

    Nakamura, N.; Nyquist, L. E.; Reese, Y.; Shih, C-Y; Fujitani, T.; Okano, O.

    2011-01-01

    We have established a precise analytical technique for stable chlorine isotope measurements of tiny planetary materials by TIMS (Thermal Ionization Mass Spectrometry) [1], for which the results are basically consistent with the IRMS tech-nique (gas source mass spectrometry) [2,3,4]. We present here results for Martian shergottites and nakhlites; whole rocks, HNO3-leachates and residues, and discuss the chlorine isotope evolution of planetary Mars.

  4. Amino acid residues 196–225 of LcrV represent a plague protective epitope

    PubMed Central

    Quenee, Lauriane E.; Berube, Bryan J.; Segal, Joshua; Elli, Derek; Ciletti, Nancy A.; Anderson, Deborah; Schneewind, Olaf

    2010-01-01

    LcrV, a protein that resides at the tip of the type III secretion needles of Yersinia pestis, is the single most important plague protective antigen. Earlier work reported monoclonal antibody MAb 7.3, which binds a conformational epitope of LcrV and protects experimental animals against lethal plague challenge. By screening monoclonal antibodies directed against LcrV for their ability to protect immunized mice against bubonic plague challenge, we examined here the possibility of additional protective epitopes. MAb BA5 protected animals against plague, neutralized the Y. pestis type III secretion pathway and promoted opsonophagocytic clearance of bacteria in blood. LcrV residues 196–225 were necessary and sufficient for MAb-BA5 binding. Compared to full length LcrV, a variant lacking its residues 196–225 retained the ability of eliciting plague protection. These results identify LcrV residues 196–225 as a linear epitope that is recognized by the murine immune system to confer plague protection. PMID:20005318

  5. Radionuclide Leaching from Residual Solids Remaining after Acid Dissolution of K East Area Sludge Composite

    SciTech Connect

    Delegard, C.H.; Rinehart, D.E.; Carlson, C.D.; Soderquist, C.Z.; Fadeff, S.K.

    1999-04-02

    Laboratory tests were performed to examine the efficacy of various leach treatments for decontaminating dissolver residual solids (KEACRESID1) produced during a 24-hour dissolution of K East Basin floor and Weasel Pit sludge composite in boiling 6 M HNO{sub 3}. The scope of this testing has been described in Section 4.5 of ''Testing Strategy to Support the Development of K Basin Sludge Treatment Process'' (Flament 1998). Radionuclides sorbed or associated with the residual solids generated in the K Basin sludge treatment process can restrict disposal of this solid to the Environmental Restoration Disposal Facility (ERDF). The starting dissolver residual solid for this testing, KEACRESID1, is a visibly heterogeneous material. This material contains radionuclides at concentrations above the ERDF Waste Acceptance Criteria for transuranics (TRU) by about a factor of 3, for {sup 239}Pu by a factor of 10, and for {sup 241}Am by a factor of 1.6. It meets the ERDF criterion for {sup 137}Cs by a factor of 4 and for uranium by a factor of 10. Therefore, the radionuclides of greatest interest in this leaching study are first {sup 239}Pu, and then {sup 241}Am, {sup 137}Cs, and uranium.

  6. Delivery of a foreign epitope by sharing amino acid residues with the carrier matrix.

    PubMed

    Cheong, Wan-Shoo; Drummer, Heidi Edelgard; Netter, Hans-Jürgen

    2009-06-01

    A broad range of structural viral proteins has the ability to assemble into virus-like particles (VLPs). Under the condition that modified subunits are still competent to assemble into VLPs, they are epitope delivery platforms suitable for vaccination purposes. The insertion of foreign sequences can be detrimental for the formation of chimeric VLPs as a result of misfolded subunit proteins. Hence, a strategy was adopted to screen for locations allowing the use of shared residues between the wildtype subunit sequence and the foreign insert. The insertion of a cysteine-containing sequence of hepatitis C virus (HCV) envelope protein 2 (E2) without adding an additional cysteine residue retained the ability of recombinant small hepatitis B surface antigen (HBsAg-S) to form secretion competent VLPs. A cysteine residue shared by the insert and the template protein avoided the formation of non-native disulfide bonds, and allowed the formation of VLPs. The chimeric HBsAg-S VLPs were similar to wildtype VLPs in density exposing the inserted foreign epitope and being immunogenic. Overall, the use of shared sequences between the insert and the subunit will facilitate the design of chimeric VLPs carrying multiple epitopes.

  7. Optimization of a Nucleic Acids united-RESidue 2-Point model (NARES-2P) with a maximum-likelihood approach

    SciTech Connect

    He, Yi; Scheraga, Harold A.; Liwo, Adam

    2015-12-28

    Coarse-grained models are useful tools to investigate the structural and thermodynamic properties of biomolecules. They are obtained by merging several atoms into one interaction site. Such simplified models try to capture as much as possible information of the original biomolecular system in all-atom representation but the resulting parameters of these coarse-grained force fields still need further optimization. In this paper, a force field optimization method, which is based on maximum-likelihood fitting of the simulated to the experimental conformational ensembles and least-squares fitting of the simulated to the experimental heat-capacity curves, is applied to optimize the Nucleic Acid united-RESidue 2-point (NARES-2P) model for coarse-grained simulations of nucleic acids recently developed in our laboratory. The optimized NARES-2P force field reproduces the structural and thermodynamic data of small DNA molecules much better than the original force field.

  8. Influence of the amino acid residue downstream of (Asp)4Lys on enterokinase cleavage of a fusion protein.

    PubMed

    Hosfield, T; Lu, Q

    1999-04-10

    We have studied the cleavage efficiency of the protease enterokinase (EK) using the novel vector pESP4. pESP4 is a yeast expression vector equipped with ligation-independent cloning sites, a GST purification tag, and a FLAG epitope tag. EK is used to cleave the FLAG and GST tags leaving the protein of interest without any extraneously added amino acids. We have found that EK is relatively permissive of the amino acid residue downstream of the recognition sequence (the P'1 position). This makes EK an ideal choice to use as a protease to cleave any protein of interest cloned within the pESP4 yeast expression vector.

  9. Optimization of a Nucleic Acids united-RESidue 2-Point model (NARES-2P) with a maximum-likelihood approach

    PubMed Central

    He, Yi; Liwo, Adam; Scheraga, Harold A.

    2015-01-01

    Coarse-grained models are useful tools to investigate the structural and thermodynamic properties of biomolecules. They are obtained by merging several atoms into one interaction site. Such simplified models try to capture as much as possible information of the original biomolecular system in all-atom representation but the resulting parameters of these coarse-grained force fields still need further optimization. In this paper, a force field optimization method, which is based on maximum-likelihood fitting of the simulated to the experimental conformational ensembles and least-squares fitting of the simulated to the experimental heat-capacity curves, is applied to optimize the Nucleic Acid united-RESidue 2-point (NARES-2P) model for coarse-grained simulations of nucleic acids recently developed in our laboratory. The optimized NARES-2P force field reproduces the structural and thermodynamic data of small DNA molecules much better than the original force field. PMID:26723596

  10. Molecular design of glycoprotein mimetics: glycoblotting by engineered proteins with an oxylamino-functionalized amino acid residue.

    PubMed

    Matsubara, Naoki; Oiwa, Kei; Hohsaka, Takahiro; Sadamoto, Reiko; Niikura, Kenichi; Fukuhara, Norio; Takimoto, Akio; Kondo, Hirosato; Nishimura, Shin-Ichiro

    2005-11-18

    The general and efficient method for the site-directed glycosylation of proteins is a key step in order to understand the biological importance of the carbohydrate chains of proteins and to control functional roles of the engineered glycoproteins in terms of the development of improved glycoprotein therapeutics. We have developed a novel method for site-directed glycosylation of proteins based on chemoselective blotting of common reducing sugars by genetically encoded proteins. The oxylamino-functionalized L-homoserine residues, 2-amino-4-O-(N-methylaminooxy) butanoic acid and 2-amino-4-aminooxy butanoic acid, were efficiently incorporated into proteins by using the four-base codon/anticodon pair strategy in Escherichia coli in vitro translation. Direct and chemoselective coupling between unmodified simple sugars and N-methylaminooxy group displayed on the engineered streptavidin allowed for the combinatorial synthesis of novel glycoprotein mimetics.

  11. Improving volatile fatty acids production by exploiting the residual substrates in post-fermented sludge: Protease catalysis of refractory protein.

    PubMed

    Yin, Bo; Liu, Hongbo; Wang, Yuanyuan; Bai, Jie; Liu, He; Fu, Bo

    2016-03-01

    The real cause to the low yield of volatile fatty acids (VFAs), from inhibition or low biodegradation, is uncertain in sludge anaerobic fermentation. In this study, poor biodegradability of proteins and fast decrease of the indigenous hydrolase activity in the residual post-fermented sludge were found to be the major reasons. With the addition of trypsin or alkaline protease in residual post-fermented sludge after primary alkaline fermentation, degradation efficiency of refractory protein increased by 33.6% and 34.8%, respectively. Accordingly, the VFAs yields were improved by 69.7% and 106.1%, respectively. Furthermore, the activities of added trypsin and alkaline protease could maintain at 13.52 U/mL and 19.11 U/mL in the alkaline fermentation process. This study demonstrated that exploiting the refractory proteins in residual post-fermented sludge by protease addition seems to be a very promising way for improving VFAs yield of conventional alkaline fermentations with waste activated sludge.

  12. An eleven amino acid residue deletion expands the substrate specificity of acetyl xylan esterase II (AXE II) from Penicillium purpurogenum

    NASA Astrophysics Data System (ADS)

    Colombres, Marcela; Garate, José A.; Lagos, Carlos F.; Araya-Secchi, Raúl; Norambuena, Patricia; Quiroz, Soledad; Larrondo, Luis; Pérez-Acle, Tomas; Eyzaguirre, Jaime

    2008-01-01

    The soft-rot fungus Penicillium purpurogenum secretes to the culture medium a variety of enzymes related to xylan biodegradation, among them three acetyl xylan esterases (AXE I, II and III). AXE II has 207 amino acids; it belongs to family 5 of the carbohydrate esterases and its structure has been determined by X-ray crystallography at 0.9 Å resolution (PDB 1G66). The enzyme possesses the α/β hydrolase fold and the catalytic triad typical of serine esterases (Ser90, His187 and Asp175). AXE II can hydrolyze esters of a large variety of alcohols, but it is restricted to short chain fatty acids. An analysis of its three-dimensional structure shows that a loop that covers the active site may be responsible for this strict specificity. Cutinase, an enzyme that hydrolyzes esters of long chain fatty acids and shows a structure similar to AXE II, lacks this loop. In order to generate an AXE II with this broader specificity, the preparation of a mutant lacking residues involving this loop (Gly104 to Ala114) was proposed. A set of molecular simulation experiments based on a comparative model of the mutant enzyme predicted a stable structure. Using site-directed mutagenesis, the loop's residues have been eliminated from the AXE II cDNA. The mutant protein has been expressed in Aspergillus nidulans A722 and Pichia pastoris, and it is active towards a range of fatty acid esters of up to at least 14 carbons. The availability of an esterase with broader specificity may have biotechnological applications for the synthesis of sugar esters.

  13. Phenolic acids identified in sorghum distillery residue demonstrated antioxidative and anti-cold-stress properties in cultured tilapia, Oreochromis mossambicus.

    PubMed

    Lee, Shin-Mei; Lin, Jing-Jen; Liao, Chih-Yuan; Cheng, Hui-Ling; Pan, Bonnie Sun

    2014-05-21

    This study aimed to identify the bioactive compounds and evaluate the anti-cold-stress function of the sorghum distillery residue (SDR) using tilapia as an alternative animal model. The highest contents of water-soluble bioactive compounds in SDR were polyphenols, followed by tannins, anthocyanins, and flavonoids. SDR was extracted with double-distilled water, 95% ethanol, and ethyl acetate, separately. The ethanol extract (SDR-E) yielded the highest polyphenol content [15.03 mg/g of SDR dry weight (dw)], of which the EC50 value of R,R-diphenyl-β-picrylhydrazyl (DPPH) radical scavenging efficiency was 0.56 ± 0.04 mg/mL. The SDR-E suppressed the oxidation of low-density lipoproteins (LDLs) more efficiently than that of other extracts. Tilapia fed a diet containing 3.6% SDR-E decreased accumulative mortality during cold stress, of 46.2%. The accumulative morality of the control was 92.9%. The phenolic acids identified in SDR included gallic acid (0.36 ± 0.08 mg/g of SDR dw), 3,4-dihydroxybenzoic acid (0.16 ± 0.12 mg/g of SDR dw), and 4-hydroxybenzoic acid (0.49 ± 0.23 mg/g of SDR dw). Diets supplemented with 0.5% 4-hydroxybenzoic acid fed to tilapia showed a lower mortality rate than that fed 1.0% 4-hydroxybenzoic acid, comparable to that of the tilapia fed 20% SDR. The latter showed lower mortality than that of the control. These results suggested that 4-hydroxybenzoic acid is one of the major anti-cold-stress compounds in SDR.

  14. Amino acid sequence around the active-site serine residue in the acyltransferase domain of goat mammary fatty acid synthetase.

    PubMed Central

    Mikkelsen, J; Højrup, P; Rasmussen, M M; Roepstorff, P; Knudsen, J

    1985-01-01

    Goat mammary fatty acid synthetase was labelled in the acyltransferase domain by formation of O-ester intermediates by incubation with [1-14C]acetyl-CoA and [2-14C]malonyl-CoA. Tryptic-digest and CNBr-cleavage peptides were isolated and purified by high-performance reverse-phase and ion-exchange liquid chromatography. The sequences of the malonyl- and acetyl-labelled peptides were shown to be identical. The results confirm the hypothesis that both acetyl and malonyl groups are transferred to the mammalian fatty acid synthetase complex by the same transferase. The sequence is compared with those of other fatty acid synthetase transferases. PMID:3922356

  15. Absorption and metabolism of ( sup 3 H)arachidonic and ( sup 14 C)linoleic acid in essential fatty acid-deficient rats

    SciTech Connect

    Hjelte, L.; Melin, T.; Nilsson, A.; Strandvik, B. )

    1990-07-01

    ({sup 3}H)arachidonic acid (20:4) and ({sup 14}C)linoleic acid (18:2) were fed in a triolein emulsion to essential fatty acid-deficient (EFAD) rats and to age-matched controls. Tissues were analyzed for radioactivity of different lipid classes after 1, 2, and 4 h. As in earlier studies, control rats retained more ({sup 3}H)20:4 than ({sup 14}C)18:2 in all organs except adipose tissue. In EFAD rats, recovery of ({sup 14}C)18:2 was increased in small intestine, liver, heart, and kidneys. In comparison to controls, EFAD rats retained much more ({sup 14}C)18:2 in phospholipids of these organs. The increase in the incorporation of both {sup 3}H and {sup 14}C into phosphatidylethanolamine was particularly pronounced. Another striking feature was the drastic increase in the retention after 4 h of {sup 14}C in cardiolipin, which is specifically located in the inner mitochondrial membrane. In contrast, incorporation of both {sup 3}H and {sup 14}C into phosphatidylinositol was decreased or unchanged in EFAD rats. Although fecal fat excretion was increased there was no evidence for a malabsorption or an increased retention in intestinal triacyglycerol of the radioactive fatty acids in EFAD rats. The proportion of ({sup 14}C)18:2 that had been converted to ({sup 14}C)20:4 was generally low but increased significantly with time in the liver and intestine of EFAD rats.

  16. Effects of changing the essential and functional fatty acid intake of dairy calves.

    PubMed

    Hill, T M; Bateman, H G; Aldrich, J M; Schlotterbeck, R L

    2009-02-01

    There is limited information on the effects and requirements of specific fatty acids for dairy calves. The starter diet based on corn and soybean meal, which is typical in the United States, is low in C(18:3), and the ratio of C(18:2) to C(18:3) is quite high relative to recommendations for human infants. Additionally, other functional fatty acids (C(20:4), C(20:5), C(22:6)) elongated from C(18:2) and C(18:3) have proven benefits in monogastric species. Thus, the effect of adding Ca salts of flax oil (high in C(18:3)) or fish oil (high in C(20:4), C(20:5), C(22:6)) to the starter diet of calves less than 3 mo old was investigated. In trial 1, 48 Holstein bull calves [43.2 +/- 1.4 kg of body weight (BW); 12/treatment] that were 2 to 3 d of age were fed 1 of 4 starter treatments containing A) no flax or fish oil (control), B) 0.125% Ca salt of flax oil, C) 0.250% Ca salt of flax oil, or D) 0.250% Ca salt of fish oil. Starters and water were fed free-choice to calves. During the first 56 d, calves were individually penned. From arrival until d 28, calves were fed a 26% crude protein, 17% fat milk replacer. From 56 to 84 d, calves were penned in groups of 6 and maintained on their same starter blended with 5% chopped grass hay. Trial 2 used 96 Holstein steer calves (66.3 +/- 3.11 kg of BW; 24/treatment) that were 59 to 60 d old in a 28-d trial. These calves had been managed for their first 56 d in the same way as the calves from trial 1 before starting trial 2. Trial 2 evaluated increasing concentrations of Ca salt of flax oil within a starter blended with 5% chopped grass hay and fed with water free-choice. The 4 treatments were A) 0%, B) 0.083%, C) 0.167%, and D) 0.250% Ca salt of flax oil. In trial 1, there were no differences among calves fed the control diet and calves fed the diet supplemented with flax oil. In trial 1, average daily gain (ADG) increased linearly as flax oil increased in the starter from d 0 to 56 and from d 56 to 84, and hip width change

  17. Prediction of fatty acid-binding residues on protein surfaces with three-dimensional probability distributions of interacting atoms.

    PubMed

    Mahalingam, Rajasekaran; Peng, Hung-Pin; Yang, An-Suei

    2014-08-01

    Protein-fatty acid interaction is vital for many cellular processes and understanding this interaction is important for functional annotation as well as drug discovery. In this work, we present a method for predicting the fatty acid (FA)-binding residues by using three-dimensional probability density distributions of interacting atoms of FAs on protein surfaces which are derived from the known protein-FA complex structures. A machine learning algorithm was established to learn the characteristic patterns of the probability density maps specific to the FA-binding sites. The predictor was trained with five-fold cross validation on a non-redundant training set and then evaluated with an independent test set as well as on holo-apo pair's dataset. The results showed good accuracy in predicting the FA-binding residues. Further, the predictor developed in this study is implemented as an online server which is freely accessible at the following website, http://ismblab.genomics.sinica.edu.tw/.

  18. Proteomic Investigation of Protein Profile Changes and Amino Acid Residue Level Modification in Cooked Lamb Meat: The Effect of Boiling.

    PubMed

    Yu, Tzer-Yang; Morton, James D; Clerens, Stefan; Dyer, Jolon M

    2015-10-21

    Hydrothermal treatment (heating in water) is a common method of general food processing and preparation. For red-meat-based foods, boiling is common; however, how the molecular level effects of this treatment correlate to the overall food properties is not yet well-understood. The effects of differing boiling times on lamb meat and the resultant cooking water were here examined through proteomic evaluation. The longer boiling time was found to result in increased protein aggregation involving particularly proteins such as glyceraldehyde-3-phosphate dehydrogenase, as well as truncation in proteins such as in α-actinin-2. Heat-induced protein backbone cleavage was observed adjacent to aspartic acid and asparagine residues. Side-chain modifications of amino acid residues resulting from the heating, including oxidation of phenylalanine and formation of carboxyethyllysine, were characterized in the cooked samples. Actin and myoglobin bands from the cooked meat per se remained visible on sodium dodecyl sulfate-polyacrylamide gel electrophoresis, even after significant cooking time. These proteins were also found to be the major source of observed heat-induced modifications. This study provides new insights into molecular-level modifications occurring in lamb meat proteins during boiling and a protein chemistry basis for better understanding the effect of this common treatment on the nutritional and functional properties of red-meat-based foods.

  19. Analysis of amino acids in latent fingerprint residue by capillary electrophoresis-mass spectrometry.

    PubMed

    Atherton, Tom; Croxton, Ruth; Baron, Mark; Gonzalez-Rodriguez, Jose; Gámiz-Gracia, Laura; García-Campaña, Ana M

    2012-11-01

    The analysis of the chemical composition of fingerprints is important for the development and improvement of existing fingerprint enhancement techniques. This study demonstrates the first analysis of a latent fingerprint sample, using an optimized CE-MS method. In total 12 amino acids were detected in the fingerprint sample. MS/MS fragmentation was used to provide additional identity confirmation, for which eight of the twelve detected amino acids generated confirmatory product ions. Nine amino acids were quantified and their relative abundances were consistent with previous studies with serine and glycine being the most abundant. The successful detection of amino acids from latent fingerprints demonstrates that CE-MS is a potential future technique for further study of such compounds in fingerprint samples.

  20. Influence of residual elements in lead on oxygen- and hydrogen-gassing rates of lead-acid batteries

    NASA Astrophysics Data System (ADS)

    Lam, L. T.; Ceylan, H.; Haigh, N. P.; Lwin, T.; Rand, D. A. J.

    Raw lead materials contain many residual elements. With respect to setting 'safe' levels for these elements, each country has its own standard, but the majority of the present specifications for the lead used to prepare battery oxide apply to flooded batteries that employ antimonial grids. In these batteries, the antimony in the positive and negative grids dominates gassing characteristics so that the influence of residual elements is of little importance. This is, however, not the case for valve-regulated lead-acid (VRLA) batteries, which use antimony-free grids and less sulfuric acid solution. Thus, it is necessary to specify 'acceptable' levels of residual elements for the production of VRLA batteries. In this study, 17 elements are examined, namely: antimony, arsenic, bismuth, cadmium, chromium, cobalt, copper, germanium, iron, manganese, nickel, selenium, silver, tellurium, thallium, tin, and zinc. The following strategy has been formulated to determine the acceptable levels: (i) selection of a control oxide; (ii) determination of critical float, hydrogen and oxygen currents; (iii) establishment of a screening plan for the elements; (iv) development of a statistical method for analysis of the experimental results. The critical values of the float, hydrogen and oxygen currents are calculated from a field survey of battery failure data. The values serve as a base-line for comparison with the corresponding measured currents from cells using positive and negative plates produced either from the control oxide or from oxide doped with different levels of the 17 elements in combination. The latter levels are determined by means of a screening plan which is based on the Plackett-Burman experimental design. Following this systematic and thorough exercise, two specifications are proposed for the purity of the lead to be used in oxide production for VRLA technology.

  1. Essential role for acid sphingomyelinase-inhibited autophagy in melanoma response to cisplatin.

    PubMed

    Cervia, Davide; Assi, Emma; De Palma, Clara; Giovarelli, Matteo; Bizzozero, Laura; Pambianco, Sarah; Di Renzo, Ilaria; Zecchini, Silvia; Moscheni, Claudia; Vantaggiato, Chiara; Procacci, Patrizia; Clementi, Emilio; Perrotta, Cristiana

    2016-05-03

    The sphingolipid metabolising enzyme Acid Sphingomyelinase (A-SMase) has been recently shown to inhibit melanoma progression and correlate inversely to tumour grade. In this study we have investigated the role of A-SMase in the chemo-resistance to anticancer treatmentusing mice with melanoma allografts and melanoma cells differing in terms of expression/activity of A-SMase. Since autophagy is emerging as a key mechanism in tumour growth and chemo-resistance, we have also investigated whether an action of A-SMase in autophagy can explain its role. Melanoma sensitivity to chemotherapeutic agent cisplatin in terms of cell viability/apoptosis, tumour growth, and animal survival depended directly on the A-SMase levels in tumoural cells. A-SMase action was due to inhibition of autophagy through activation of Akt/mammalian target of rapamycin (mTOR) pathway. Treatment of melanoma-bearing mice with the autophagy inhibitor chloroquine restored sensitivity to cisplatin of tumours expressing low levels of A-SMase while no additive effects were observed in tumours characterised by sustained A-SMase levels. The fact that A-SMase in melanomas affects mTOR-regulated autophagy and plays a central role in cisplatin efficacy encourages pre-clinical testing on the modulation of A-SMase levels/activity as possible novel anti-neoplastic strategy.

  2. Ketogenic essential amino acids replacement diet ameliorated hepatosteatosis with altering autophagy-associated molecules.

    PubMed

    Xu, Ling; Kanasaki, Megumi; He, Jianhua; Kitada, Munehiro; Nagao, Kenji; Jinzu, Hiroko; Noguchi, Yasushi; Maegawa, Hiroshi; Kanasaki, Keizo; Koya, Daisuke

    2013-10-01

    Ketogenic amino acid (KAA) replacement diet has been shown to cure hepatic steatosis, a serious liver disease associated with diverse metabolic defects. In this study, we investigated the effects of KAA replacement diet on nutrition sensing signaling pathway and analyzed whether induction of hepatic autophagy was involved. Mice are fed with high fat diet (HFD) or KAA replacement in high-fat diet (30% fat in food; HFD)-fed (HFD(KAAR)) and sacrificed at 8, 12, 16 weeks after initiation of experimental food. Hepatic autophagy was analyzed in protein expression of several autophagy-associated molecules and in light chain-3 green fluorescent protein (LC-3 GFP) transgenic mice. HFD(KAAR) showed increased AMP-activated protein kinase (AMPK) phosphorylation and enhanced liver kinase B1 (LKB1) expression compared to control HFD-fed mice. The KAA-HFD-induced activation of AMPK was associated with an increased protein expression of sirtuin 1 (Sirt1), decreased forkhead box protein O3a (Foxo3a) level, and suppression of mammalian target of rapamycin (mTOR) phosphorylation compared with the HFD-fed mice. The intervention study revealed that a KAA-replacement diet also ameliorated all the established metabolic and autophagy defects in the HFD-fed mice, suggesting that a KAA-replacement diet can be used therapeutically in established diseases. These results indicate that KAA replacement in food could be a novel strategy to combat hepatic steatosis and metabolic abnormalities likely involvement of an induction of autophagy.

  3. Pyelonephritis: renal urokinase activity in rats on essential fatty acid diets.

    PubMed

    du Toit, P J; van Aswegen, C H; Nel, J D; Strasheim, B; Becker, P J; du Plessis, D J

    1994-01-01