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Sample records for acid residues required

  1. Immobilization of acid digestion residue

    International Nuclear Information System (INIS)

    Greenhalgh, W.O.; Allen, C.R.

    1983-01-01

    Acid digestion treatment of nuclear waste is similar to incineration processes and results in the bulk of the waste being reduced in volume and weight to some residual solids termed residue. The residue is composed of various dispersible solid materials and typically contains the resultant radioactivity from the waste. This report describes the immobilization of the residue in portland cement, borosilicate glass, and some other waste forms. Diagrams showing the cement and glass virtification parameters are included in the report as well as process steps and candidate waste product forms. Cement immobilization is simplest and probably least expensive; glass vitrification exhibits the best overall volume reduction ratio

  2. Acidic and uncharged polar residues in the consensus motifs of the yeast Ca2+ transporter Gdt1p are required for calcium transport.

    Science.gov (United States)

    Colinet, Anne-Sophie; Thines, Louise; Deschamps, Antoine; Flémal, Gaëlle; Demaegd, Didier; Morsomme, Pierre

    2017-07-01

    The UPF0016 family is a recently identified group of poorly characterized membrane proteins whose function is conserved through evolution and that are defined by the presence of 1 or 2 copies of the E-φ-G-D-[KR]-[TS] consensus motif in their transmembrane domain. We showed that 2 members of this family, the human TMEM165 and the budding yeast Gdt1p, are functionally related and are likely to form a new group of Ca 2+ transporters. Mutations in TMEM165 have been demonstrated to cause a new type of rare human genetic diseases denominated as Congenital Disorders of Glycosylation. Using site-directed mutagenesis, we generated 17 mutations in the yeast Golgi-localized Ca 2+ transporter Gdt1p. Single alanine substitutions were targeted to the highly conserved consensus motifs, 4 acidic residues localized in the central cytosolic loop, and the arginine at position 71. The mutants were screened in a yeast strain devoid of both the endogenous Gdt1p exchanger and Pmr1p, the Ca 2+ -ATPase of the Golgi apparatus. We show here that acidic and polar uncharged residues of the consensus motifs play a crucial role in calcium tolerance and calcium transport activity and are therefore likely to be architectural components of the cation binding site of Gdt1p. Importantly, we confirm the essential role of the E53 residue whose mutation in humans triggers congenital disorders of glycosylation. © 2017 John Wiley & Sons Ltd.

  3. Disappearing or residual tiny (≤5 mm) colorectal liver metastases after chemotherapy on gadoxetic acid-enhanced liver MRI and diffusion-weighted imaging: Is local treatment required?

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Seung Soo [Sungkyunkwan University School of Medicine, Department of Radiology and Center for Imaging Science, Samsung Medical Center, Seoul (Korea, Republic of); Cheonan Hospital, Department of Radiology, Soonchunhyang University College of Medicine, Cheonan-si, Chungcheongnam-do (Korea, Republic of); Song, Kyoung Doo; Kim, Young Kon [Sungkyunkwan University School of Medicine, Department of Radiology and Center for Imaging Science, Samsung Medical Center, Seoul (Korea, Republic of); Kim, Hee Cheol; Huh, Jung Wook [Sungkyunkwan University School of Medicine, Department of Surgery, Samsung Medical Center, Seoul (Korea, Republic of); Park, Young Suk; Park, Joon Oh; Kim, Seung Tae [Sungkyunkwan University School of Medicine, Division of Hematology-Oncology, Department of Medicine, Samsung Medical Center, Seoul (Korea, Republic of)

    2017-07-15

    To evaluate the clinical course of disappearing colorectal liver metastases (DLM) or residual tiny (≤5 mm) colorectal liver metastases (RTCLM) on gadoxetic acid-enhanced magnetic resonance imaging (MRI) and diffusion-weighted imaging (DWI) in patients who had colorectal liver metastases (CLM) and received chemotherapy. Among 137 patients who received chemotherapy for CLM and underwent gadoxetic acid-enhanced MRI and DWI between 2010 and 2012, 43 patients with 168 DLMs and 48 RTCLMs were included. The cumulative in situ recurrence rate of DLM and progression rate of RTCLM and their predictive factors were evaluated. A total of 150 DLMs and 26 RTCLMs were followed up without additional treatment. At 1 and 2 years, respectively, the cumulative in situ recurrence rates for DLM were 10.9 % and 15.7 % and the cumulative progression rates for RTCLM were 27.2 % and 33.2 %. The in situ recurrence rate at 2 years was 4.9 % for the DLM group that did not show reticular hypointensity of liver parenchyma on hepatobiliary phase. DLM on gadoxetic acid-enhanced liver MRI and DWI indicates a high possibility of clinical complete response, especially in patients without chemotherapy-induced sinusoidal obstruction syndrome. Thirty-three percent of RTCLMs showed progression at 2 years. (orig.)

  4. A Soluble, Folded Protein without Charged Amino Acid Residues

    DEFF Research Database (Denmark)

    Højgaard, Casper; Kofoed, Christian; Espersen, Roall

    2016-01-01

    side chains can maintain solubility, stability, and function. As a model, we used a cellulose-binding domain from Cellulomonas fimi, which, among proteins of more than 100 amino acids, presently is the least charged in the Protein Data Bank, with a total of only four titratable residues. We find......Charges are considered an integral part of protein structure and function, enhancing solubility and providing specificity in molecular interactions. We wished to investigate whether charged amino acids are indeed required for protein biogenesis and whether a protein completely free of titratable...... that the protein shows a surprising resilience toward extremes of pH, demonstrating stability and function (cellulose binding) in the pH range from 2 to 11. To ask whether the four charged residues present were required for these properties of this protein, we altered them to nontitratable ones. Remarkably...

  5. A Soluble, Folded Protein without Charged Amino Acid Residues

    DEFF Research Database (Denmark)

    Højgaard, Casper; Kofoed, Christian; Espersen, Roall

    2016-01-01

    Charges are considered an integral part of protein structure and function, enhancing solubility and providing specificity in molecular interactions. We wished to investigate whether charged amino acids are indeed required for protein biogenesis and whether a protein completely free of titratable...... side chains can maintain solubility, stability, and function. As a model, we used a cellulose-binding domain from Cellulomonas fimi, which, among proteins of more than 100 amino acids, presently is the least charged in the Protein Data Bank, with a total of only four titratable residues. We find...

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

    OpenAIRE

    Kong, X.; Li, M.; Xue, S.; Hartley, W.; Chen, C.; Wu, C.; Li, X.; Li, Y.

    2016-01-01

    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...

  7. 40 CFR 158.1410 - Residue chemistry data requirements table.

    Science.gov (United States)

    2010-07-01

    ... table. 158.1410 Section 158.1410 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED... example, most products used in or near kitchens require residue data for risk assessment purposes even... NR PAIRA 7 Analytical methods 860.1340 Residue analytical methods R R R CR CR Residue of concern 1, 3...

  8. Identification of amino acid residues in protein SRP72 required for binding to a kinked 5e motif of the human signal recognition particle RNA

    Directory of Open Access Journals (Sweden)

    Zwieb Christian

    2010-11-01

    Full Text Available Abstract Background Human cells depend critically on the signal recognition particle (SRP for the sorting and delivery of their proteins. The SRP is a ribonucleoprotein complex which binds to signal sequences of secretory polypeptides as they emerge from the ribosome. Among the six proteins of the eukaryotic SRP, the largest protein, SRP72, is essential for protein targeting and possesses a poorly characterized RNA binding domain. Results We delineated the minimal region of SRP72 capable of forming a stable complex with an SRP RNA fragment. The region encompassed residues 545 to 585 of the full-length human SRP72 and contained a lysine-rich cluster (KKKKKKKKGK at postions 552 to 561 as well as a conserved Pfam motif with the sequence PDPXRWLPXXER at positions 572 to 583. We demonstrated by site-directed mutagenesis that both regions participated in the formation of a complex with the RNA. In agreement with biochemical data and results from chymotryptic digestion experiments, molecular modeling of SRP72 implied that the invariant W577 was located inside the predicted structure of an RNA binding domain. The 11-nucleotide 5e motif contained within the SRP RNA fragment was shown by comparative electrophoresis on native polyacrylamide gels to conform to an RNA kink-turn. The model of the complex suggested that the conserved A240 of the K-turn, previously identified as being essential for the binding to SRP72, could protrude into a groove of the SRP72 RNA binding domain, similar but not identical to how other K-turn recognizing proteins interact with RNA. Conclusions The results from the presented experiments provided insights into the molecular details of a functionally important and structurally interesting RNA-protein interaction. A model for how a ligand binding pocket of SRP72 can accommodate a new RNA K-turn in the 5e region of the eukaryotic SRP RNA is proposed.

  9. Identification of amino acid residues in protein SRP72 required for binding to a kinked 5e motif of the human signal recognition particle RNA.

    Science.gov (United States)

    Iakhiaeva, Elena; Iakhiaev, Alexei; Zwieb, Christian

    2010-11-13

    Human cells depend critically on the signal recognition particle (SRP) for the sorting and delivery of their proteins. The SRP is a ribonucleoprotein complex which binds to signal sequences of secretory polypeptides as they emerge from the ribosome. Among the six proteins of the eukaryotic SRP, the largest protein, SRP72, is essential for protein targeting and possesses a poorly characterized RNA binding domain. We delineated the minimal region of SRP72 capable of forming a stable complex with an SRP RNA fragment. The region encompassed residues 545 to 585 of the full-length human SRP72 and contained a lysine-rich cluster (KKKKKKKKGK) at postions 552 to 561 as well as a conserved Pfam motif with the sequence PDPXRWLPXXER at positions 572 to 583. We demonstrated by site-directed mutagenesis that both regions participated in the formation of a complex with the RNA. In agreement with biochemical data and results from chymotryptic digestion experiments, molecular modeling of SRP72 implied that the invariant W577 was located inside the predicted structure of an RNA binding domain. The 11-nucleotide 5e motif contained within the SRP RNA fragment was shown by comparative electrophoresis on native polyacrylamide gels to conform to an RNA kink-turn. The model of the complex suggested that the conserved A240 of the K-turn, previously identified as being essential for the binding to SRP72, could protrude into a groove of the SRP72 RNA binding domain, similar but not identical to how other K-turn recognizing proteins interact with RNA. The results from the presented experiments provided insights into the molecular details of a functionally important and structurally interesting RNA-protein interaction. A model for how a ligand binding pocket of SRP72 can accommodate a new RNA K-turn in the 5e region of the eukaryotic SRP RNA is proposed.

  10. Mutational properties of amino acid residues: implications for evolvability of phosphorylatable residues

    DEFF Research Database (Denmark)

    Creixell, Pau; Schoof, Erwin M.; Tan, Chris Soon Heng

    2012-01-01

    in terms of their mutational activity. Moreover, we highlight the importance of the genetic code and physico-chemical properties of the amino acid residues as likely causes of these inequalities and uncover serine as a mutational hot spot. Finally, we explore the consequences that these different......; it is typically assumed that all amino acid residues are equally likely to mutate or to result from a mutation. Here, by reconstructing ancestral sequences and computing mutational probabilities for all the amino acid residues, we refute this assumption and show extensive inequalities between different residues...... mutational properties have on phosphorylation site evolution, showing that a higher degree of evolvability exists for phosphorylated threonine and, to a lesser extent, serine in comparison with tyrosine residues. As exemplified by the suppression of serine's mutational activity in phosphorylation sites, our...

  11. Recovery of mercury from acid waste residues

    Science.gov (United States)

    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.

  12. 40 CFR 161.240 - Residue chemistry data requirements.

    Science.gov (United States)

    2010-07-01

    .../feed (5), (14) [CR] [CR] [CR] [CR] EP EP 171-4 Meat/milk/poultry/eggs (6), (14) [CR] [CR] [CR] [CR... food/feed are required when detectable residues could concentrate on processing and thus require establishment of a food additive tolerance. (6) Livestock feeding studies are required whenever a pesticide...

  13. Peptides containing internal residues of pyroglutamic acid: proton NMR characteristics

    International Nuclear Information System (INIS)

    Khan, S.A.

    1986-01-01

    The proton NMR characteristics of internal pyroglutamic acid (Glp; 5-oxoproline) residues in seven tripeptides of the general structure Boc-Xxx-Glp-Yyy-NH 2 were studied. In general, the chemical shifts of several diagnostic protons moved downfield on going from the Glu-containing peptides (Boc-Xxx-Glu-Yyy-NH 2 ) to the corresponding Glp-containing peptides. The C-2 proton of the Xxx residue was shifted by about 1.1 ppm. The N-2 proton of the Yyy residue was shifted by about 0.5 ppm. The C-2 proton of the Glx residue itself was shifted by about 0.5 ppm. One of the Glx C-3 protons was also shifted by about 0.5 ppm, but the other remained essentially unchanged. Finally, the Glx C-4 protons were shifted by about 0.3 ppm. Internal Glu residues are readily converted chemically into internal Glp residues. This conversion also occurs as a side reaction during HP cleavage of the protecting group from Glu(OBzl) residues. The spontaneous fragmentation of serum proteins C3, C4 and λ 2 -macroglobulin under denaturing conditions is probably due to regioselective hydrolysis of an internal Glp residue formed in each of these proteins upon denaturation. These proton NMR characteristics may be useful in establishing the presence of internal Glp residues in synthetic and natural peptides

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

    Science.gov (United States)

    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. Copyright © 2016 Elsevier B.V. All rights reserved.

  15. Amendment of Acid Soils with Crop Residues and Biochars

    Institute of Scientific and Technical Information of China (English)

    YUAN Jin-Hua; XU Ren-Kou; WANG Ning; LI Jiu-Yu

    2011-01-01

    The liming potential of some crop residues and their biochars on an acid Ultisol was investigated using incubation experiments. Rice hulls showed greater liming potential than rice hull biochar, while soybean and pea straws had less liming potential than their biochars. Due to their higher alkalinity, biochars from legume materials increased soil pH much compared to biochars from non-legume materials. The alkalinity of biochars was a key factor affecting their liming potential,and the greater alkalinity of biochars led to greater reductions in soil acidity. The incorporation of biochars decreased soil exchangeable acidity and increased soil exchangeable base cations and base saturation, thus improving soil fertility.

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

    Science.gov (United States)

    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.

  17. 40 CFR 158.270 - Experimental use permit data requirements for residue chemistry.

    Science.gov (United States)

    2010-07-01

    ... requirements for residue chemistry. 158.270 Section 158.270 Protection of Environment ENVIRONMENTAL PROTECTION... Experimental use permit data requirements for residue chemistry. All residue chemistry data, as described in... section 408(r) is sought. Residue chemistry data are not required for an experimental use permit issued on...

  18. 75 FR 40736 - Acetic Acid; Exemption from the Requirement of a Tolerance

    Science.gov (United States)

    2010-07-14

    ... an exemption from the requirement of a tolerance for residues of acetic acid, also known as vinegar... a maximum permissible level for residues of acetic acid, also known as vinegar. DATES: This... humans. It is also naturally produced during the fermentation process in a wide range of foods. In plants...

  19. Residual load, renewable surplus generation and storage requirements in Germany

    International Nuclear Information System (INIS)

    Schill, Wolf-Peter

    2014-01-01

    I examine the effects of increasing amounts of fluctuating renewable energy on residual load, which is defined as the difference between actual power demand and the feed-in of non-dispatchable and inflexible generators. I draw on policy-relevant scenarios for Germany and make use of extensive sensitivity analyses. Whereas yearly renewable surplus energy is low in most scenarios analyzed, peak surplus power can become very high. Decreasing thermal must-run requirements and increasing biomass flexibility substantially reduce surpluses. I use an optimization model to determine the storage capacities required for taking up renewable surpluses. Allowing curtailment of 1% of the yearly feed-in of non-dispatchable renewables would render storage investments largely obsolete until 2032 under the assumption of a flexible power system. Further restrictions of curtailment as well as lower system flexibility strongly increase storage requirements. By 2050, at least 10 GW of storage are required for surplus integration, of which a sizeable share is seasonal storage. Results suggest that policy makers should work toward avoiding surplus generation, in particular by decreasing the must-run of thermal generators. Concerns about surpluses should not be regarded as an obstacle to further renewable expansion. The findings are also relevant for other countries that shift toward fluctuating renewables. - Highlights: • I examine the effects of fluctuating renewable energy on residual load. • Surplus energies are generally low, but there are high surplus power peaks. • Increasing the flexibility of thermal generators substantially reduces surpluses. • Allowing curtailment of 1% renders storage investments largely obsolete by 2032. • Both storage requirements and the share of seasonal storage increase by 2050

  20. XPS and STEM studies of Allende acid insoluble residues

    Science.gov (United States)

    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. Treatment of the acid mine drainage residue for uranium recovery

    International Nuclear Information System (INIS)

    Dias, M.M.; Horta, D.G.; Fukuma, H.T.; Villegas, R.A.S.; Carvalho, C.H.T. de; Silva, A.C. da

    2017-01-01

    Acid mine drainage (AMD) is a process that occurs in many mining that have sulfide ores. With water and oxygen, several metals are oxidized, one example being uranium. At the mine pit of the Osamu Utsumi Mine located at INB - Caldas and in two other boot-wastes (mining waste pile), AMD is present and currently, without a technological solution. The acidic water present in the pit is treated with hydrated lime, generating water for disposal and an alkaline residue called calcium diuranate - DUCA. The DUCA has a concentration of approximately 0.32% U 3 O 8 , which makes interesting the development of a process for extracting that metal. One of the processes that can be used is leaching. For this study, it was decided to evaluate the alkaline leaching to extract the uranium present in the residue. It is necessary to optimize operational parameters for the process: percentage of solids, concentration of leaching agent in solution, temperature and reaction time. With these parameters, it is possible to improve the leaching so that the largest amount of uranium is extracted from the sample, to help solve the environmental impact caused by the wastewater from the treatment of acid waters and, in addition, to give an economical destination for this metal that is contained in the deposited DUCA

  2. Analysis of abietic acid and dehydroabietic acid residues in raw ducks and cooked ducks.

    Science.gov (United States)

    Zhu, Yongzhi; Zhang, Suzhen; Geng, Zhiming; Wang, Daoying; Liu, Fang; Zhang, Muhan; Bian, Huan; Xu, Weimin

    2014-10-01

    Rosin was once widely used for removal of duck feathers in China and is still being used secretly in some poultry processing enterprises. Abietic acid (AA) and dehydroabietic acid (DHAA) are the major compounds of rosin. In the present study, 90 duck samples were collected for investigation of AA and DHAA residues. Abietic acid and DHAA were simultaneously detected in 13 out 40 raw ducks, 8 out of 26 water-boiled salted ducks, and 7 out of 24 roasted ducks, respectively. In positive samples, averages of AA were significantly higher than those of DHAA in positive samples of the 3 types of ducks (P ducks were significantly higher than those in positive roasted ducks (P ducks were defeathered by means of rosin-containing defeathering agent, and cooking processes could reduce the AA and DHAA residues to some extent, but could not eliminate them completely. ©2014 Poultry Science Association Inc.

  3. Gamma-aminobutyric acid fermentation with date residue by a lactic acid bacterium, Lactobacillus brevis.

    Science.gov (United States)

    Hasegawa, Momoko; Yamane, Daisuke; Funato, Kouichi; Yoshida, Atsushi; Sambongi, Yoshihiro

    2018-03-01

    Dates are commercially consumed as semi-dried fruit or processed into juice and puree for further food production. However, the date residue after juice and puree production is not used, although it appears to be nutrient enriched. Here, date residue was fermented by a lactic acid bacterium, Lactobacillus brevis, which has been generally recognized as safe. Through degradation of sodium glutamate added to the residue during the fermentation, γ-aminobutyric acid (GABA), which reduces neuronal excitability, was produced at the conversion rate of 80-90% from glutamate. In order to achieve this GABA production level, pretreatment of the date residue with carbohydrate-degrading enzymes, i.e., cellulase and pectinase, was necessary. All ingredients used for this GABA fermentation were known as being edible. These results provide us with a solution for the increasing commercial demand for GABA in food industry with the use of date residue that has been often discarded. Copyright © 2017 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

  4. Linoleic acid intake and vitamin E requirement

    NARCIS (Netherlands)

    Jager, F.C.

    1973-01-01

    In experiments with rats and Peking ducklings it has been investigated to what extent the linoleic acid content of the diet is of influence on the requirement of vitamin E. This requirement was determined by adding D-α-tocopheryl acetate in increasing doses to vitamin E-free diets and to determine

  5. Determination of thymine glycol residues in irradiated or oxidized DNA by formation of methylglyceric acid

    International Nuclear Information System (INIS)

    Schellenberg, K.A.; Shaeffer, J.

    1986-01-01

    Treatment of DNA solutions with X-irradiation various oxidants including hydrogen peroxide plus ferrous ion, hydrogen peroxide plus copper ion and ascorbate, permanganate, or sonication in the presence of dissolved oxygen all produced varying amounts of thymine glycol residues. After denaturing the DNA with heat, the glycol residues were reduced and labeled at the 6 position with tritium- labeled sodium borohydride. Subsequent reaction with anhydrous methanolic HCl gave a quantitative yield of the methyl ester of methylglyceric acid, which was determined by thin layer chromatography. The method, developed using thymidine as a model, was used to ascertain the requirements for glycol formation in DNA. It was shown that hydroxyl radical generating systems, permanganate, X-irradiation, or sonication in presence of oxygen were required, but hydrogen peroxide in the absence of iron or copper and ascorbate was inactive. Application to determination of DNA damage in vivo is being explored

  6. Acid leaching of uranium present in a residue from mining industry

    Energy Technology Data Exchange (ETDEWEB)

    Braulio, Walace S.; Ladeira, Ana C.Q. [Center for Development of Nuclear Technology (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil). Dept. of Mineral Technology

    2011-07-01

    The acid mine drainage is one of the most important environmental problems associated with mining of ores containing sulfides. The treatment of these acid effluents, which contains high concentrations of dissolved metals and anions, is generally by liming. The wastes generated in the liming process may present significant toxicity and their storage in inappropriate places waiting for treatment is a common issue that requires solution. Osamu Utsumi Mine located in the city of Caldas, Minas Gerais, has been facing this problem. The residue of this mine consists of an alkaline sludge generated from the neutralization of the pH of acid mine drainage and is rich in various metals, including uranium. The main concern is the long term stability of this residue, which is in permanent contact with the acid water in the open pit. The recovery of uranium by hydrometallurgical techniques, such as acid leaching, can be a viable alternative on the reuse of this material. This study aimed at establishing a specific leaching process for the recovery of uranium present in the sludge from Caldas uranium mine. Some parameters such as solid/liquid ratio (0.09 to 0.17), time of leaching (1 to 24 hours) and concentration of sulfuric acid (pH from 0 to 3.0) were assessed. The results showed that it is possible to extract 100% of uranium present in the sludge. The concentration of U{sub 3}O{sub 8} in the residue was 0.25%, similar to the content of the vein ores which is around 0.20% to 1.0%. The best experimental leaching condition is solid/liquid ratio of 0.17, pH 1.0 and 2 hours of reaction at room temperature (25 deg C). The content of uranium in the liquor is around 440 mgL{sup -1}. The recovery of the uranium from the liquor is under investigation by ionic exchange. (author)

  7. Acid leaching of uranium present in a residue from mining industry

    International Nuclear Information System (INIS)

    Braulio, Walace S.; Ladeira, Ana C.Q.

    2011-01-01

    The acid mine drainage is one of the most important environmental problems associated with mining of ores containing sulfides. The treatment of these acid effluents, which contains high concentrations of dissolved metals and anions, is generally by liming. The wastes generated in the liming process may present significant toxicity and their storage in inappropriate places waiting for treatment is a common issue that requires solution. Osamu Utsumi Mine located in the city of Caldas, Minas Gerais, has been facing this problem. The residue of this mine consists of an alkaline sludge generated from the neutralization of the pH of acid mine drainage and is rich in various metals, including uranium. The main concern is the long term stability of this residue, which is in permanent contact with the acid water in the open pit. The recovery of uranium by hydrometallurgical techniques, such as acid leaching, can be a viable alternative on the reuse of this material. This study aimed at establishing a specific leaching process for the recovery of uranium present in the sludge from Caldas uranium mine. Some parameters such as solid/liquid ratio (0.09 to 0.17), time of leaching (1 to 24 hours) and concentration of sulfuric acid (pH from 0 to 3.0) were assessed. The results showed that it is possible to extract 100% of uranium present in the sludge. The concentration of U 3 O 8 in the residue was 0.25%, similar to the content of the vein ores which is around 0.20% to 1.0%. The best experimental leaching condition is solid/liquid ratio of 0.17, pH 1.0 and 2 hours of reaction at room temperature (25 deg C). The content of uranium in the liquor is around 440 mgL -1 . The recovery of the uranium from the liquor is under investigation by ionic exchange. (author)

  8. Finding coevolving amino acid residues using row and column weighting of mutual information and multi-dimensional amino acid representation

    DEFF Research Database (Denmark)

    Oliveira, Rodrigo Gouveia; Pedersen, Anders Gorm

    2007-01-01

    ABSTRACT: BACKGROUND: Some amino acid residues functionally interact with each other. This interaction will result in an evolutionary co-variation between these residues - coevolution. Our goal is to find these coevolving residues. RESULTS: We present six new methods for detecting coevolving...... residues. Among other things, we suggest measures that are variants of Mutual Information, and measures that use a multidimensional representation of each residue in order to capture the physico-chemical similarities between amino acids. We created a benchmarking system, in silico, able to evaluate...

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

    Science.gov (United States)

    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. Copyright © 2011 Elsevier Ltd. All rights reserved.

  10. Characteristics of a continuous denitration by formic acid - electrolytic trimming of residual acid with accompanying the precipitation of metal ions

    International Nuclear Information System (INIS)

    Kim, G. W.; Kim, S. H.; Lim, J. G.; Lee, I. H.

    2003-01-01

    This work has studied the characteristics of destruction of nitric acid and precipitation of several metal ions in a continuous denitration process combining a denitration by formic acid and a residual acid-electrolytic trimming system. The metal ions of Zr, Mo, Fe, and Nd did not affect the electrodes at the step of electrolytic trimming of the residual acid after denitration by formic acid. The Mo ion in electrolytic solution enhanced the generation of nitrite ion during the electrolytic reaction. The mole ratio of formic acid to nitric acid fed into the continuous denitration reactor using formic acid affected much the final acidity, the precipitation yields of metal ions, the precipitate morphology. At the ratio of 1.65, the process had the lowest final acidity of less than 0.1 M, and the precipitation yields of Zr and Mo reached 95% and 83%, respectively as the highest values

  11. Residue Geometry Networks: A Rigidity-Based Approach to the Amino Acid Network and Evolutionary Rate Analysis

    Science.gov (United States)

    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

  12. Hydrogen bond strengths in phosphorylated and sulfated amino acid residues.

    Directory of Open Access Journals (Sweden)

    Chaya Rapp

    Full Text Available Post-translational modification by the addition of an oxoanion functional group, usually a phosphate group and less commonly a sulfate group, leads to diverse structural and functional consequences in protein systems. Building upon previous studies of the phosphoserine residue (pSer, we address the distinct nature of hydrogen bonding interactions in phosphotyrosine (pTyr and sulfotyrosine (sTyr residues. We derive partial charges for these modified residues and then study them in the context of molecular dynamics simulation of model tripeptides and sulfated protein complexes, potentials of mean force for interacting residue pairs, and a survey of the interactions of modified residues among experimental protein structures. Overall, our findings show that for pTyr, bidentate interactions with Arg are particularly dominant, as has been previously demonstrated for pSer. sTyr interactions with Arg are significantly weaker, even as compared to the same interactions made by the Glu residue. Our work sheds light on the distinct nature of these modified tyrosine residues, and provides a physical-chemical foundation for future studies with the goal of understanding their roles in systems of biological interest.

  13. Effect of cooking on residues of the quinolones oxolinic acid and flumequine in fish.

    Science.gov (United States)

    Steffenak, I; Hormazabal, V; Yndestad, M

    1994-01-01

    The effect of cooking on residues of the quinolones oxolinic acid and flumequine in fish was investigated. Salmon containing residues of oxolinic acid and flumequine was boiled or baked in the oven. Samples of raw and cooked muscle, skin, and bone, as well as of the water in which the fish was boiled and juice from the baked fish, were analysed. Oxolinic acid and flumequine did not degrade at the temperatures reached when cooking the fish. However, fish muscle free from drug residues may be contaminated during boiling and baking due to leakage of the drug from reservoirs in the fish.

  14. The effect of delignification process with alkaline peroxide on lactic acid production from furfural residues

    Directory of Open Access Journals (Sweden)

    Yong Tang

    2012-11-01

    Full Text Available Furfural residues produced from the furfural industry were investigated as a substrate for lactic acid production by simultaneous saccharification and fermentation (SSF. Alkaline peroxide was used for delignification of furfural residues to improve the final lactic acid concentration. The residue was treated with 1.3% to 1.7% hydrogen peroxide at 80 °C for 1 h with a substrate concentration of 3.33%. SSF of furfural residues with different delignification degrees were carried out to evaluate the effect of delignification degree on lactic acid production. Using corn hydrolysates/ furfural residues as substrates, SSF with different media were carried out to investigate the effect of lignin on the interaction between enzymes and lactic acid bacteria. Lactic acid bacteria had a negative effect on cellulase, thus resulting in the reduction of enzyme activity. Lignin and nutrients slowed down the decreasing trend of enzyme activity. A higher delignification resulted in a slower fermentation rate and lower yield due to degradation products of lignin and the effect of lignin on the interaction between enzymes and lactic acid bacteria. For the purpose of lactic acid production, a moderate delignification (furfural residues with the lignin content of 14.8% was optimum.

  15. 40 CFR 158.2172 - Experimental use permit microbial pesticides residue data requirements table.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 23 2010-07-01 2010-07-01 false Experimental use permit microbial....2172 Experimental use permit microbial pesticides residue data requirements table. (a) General. Sections 158.100 through 158.130 describe how to use this table to determine the residue chemistry data...

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

    International Nuclear Information System (INIS)

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

    1990-01-01

    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. 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 3 H 4 followed by complete acid hydrolysis yielded [ 3 H] glucosaminitol from the true reducing end residue of teichuronic acid and [ 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

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

    Science.gov (United States)

    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. Copyright © 2016 Elsevier Ltd. All rights reserved.

  18. Fermentative utilization of glycerol residue for the production of acetic acid

    Science.gov (United States)

    Irvan; Trisakti, B.; Hasibuan, R.; Joli, M.

    2018-02-01

    Glycerol residue, frequently known as pitch, is a waste produced from the downstream product of crude glycerine distillation. With the increasing need of pure glycerine in the world, the glycerol residue produced is also increasing. Glycerol residue is a solid waste at room temperature, highly alkaline (pH > 13), corrosive, and categorized as hazardous and poisonous waste. In this research, acetic acid was produced from glycerol residue through the anaerobic fermentation process by using purple non-sulphur photosynthetic bacteria. The purpose of this study was to find out the influence of concentration change of glycerol residue on time and to find out the possibility of glycerol residue to be utilized as acetic acid. In this research, at first 400 g of glycerol residue was diluted with 200 ml of distilled water to change the glycerine phase, from solid to liquid at room temperature, acidified by using hydrochloric acid until pH 2. The top layer formed was fatty acid and triglycerides that should be removed. Meanwhile, the bottom layer was diluted glycerol residue which was then neutralized with caustic soda. To produce acetic acid, glycerol residue with various concentrations, salt, and purple non-sulphur photosynthetic bacteria were put together into a 100 ml bottle which had been previously sterilized, then incubated for four weeks under the light of 40-watt bulb. The result showed that on the 28th day of fermentation, the produced acetic acid were 0.28, 1.85, and 0.2% (w/w) by using glycerine with the concentration of 0.5, 1.0, and 1.5% (w/w), respectively.

  19. Plant residues: short term effect on sulphate, borate, zinc and copper adsorption by an acid oxisol

    Directory of Open Access Journals (Sweden)

    Dias Ana Cristi Basile

    2003-01-01

    Full Text Available Laboratory experiments were carried out to examine the effects of plant residues on Cu, Zn, B and S adsorption by an acidic oxisol. The plant residues were: black oats (Avena strigosa, oil seed radish(Raphanus sativus, velvet beans (Stizolobium cinereum, and pigeon pea (Cajanus cajan collected at flowering stage. Plant residues increased Cu and Zn adsorptions and decreased B and S adsorptions. The results indicated that for short term effect plant residues decreased the availabilities of Cu and Zn through metal organic complex reactions and increased availabilities of S and B through competition with organic anions by the adsorption sites on soil.

  20. Irradiation and modified atmosphere packaging effects on residual nitrite, ascorbic acid, nitrosomyoglobin, and color in sausage.

    Science.gov (United States)

    Ahn, Hyun-Joo; Jo, Cheorun; Lee, Ju-Woon; Kim, Jae-Hyun; Kim, Kee-Hyuk; Byun, Myung-Woo

    2003-02-26

    The present study was undertaken to evaluate the irradiation and modified atmosphere packaging effects on emulsion-type cooked pork sausage during storage for 4 weeks. CO(2) (100%), N(2) (100%), or 25% CO(2)/75% N(2) packaged sausage were irradiated at 0, 5, and 10 kGy, and residual nitrite, residual ascorbic acid, nitrosomyoglobin (NO-Mb), color values, and their correlation were observed. Irradiation significantly reduced the residual nitrite content and caused partial reduction of NO-Mb during storage. No difference was observed in ascorbic acid content by irradiation. Irradiation decreased the Hunter color a value of sausage. CO(2) or CO(2)/N(2) packaging were more effective for reducing residual nitrite and inhibiting the loss of the red color of sausage compared to N(2) packaging. Results indicated that the proper combination of irradiation and modified atmosphere packaging could reduce the residual nitrite in sausage with minimization of color change.

  1. Coevolution of amino acid residues in the key photosynthetic enzyme Rubisco

    Directory of Open Access Journals (Sweden)

    Kapralov Maxim V

    2011-09-01

    Full Text Available Abstract Background One of the key forces shaping proteins is coevolution of amino acid residues. Knowing which residues coevolve in a particular protein may facilitate our understanding of protein evolution, structure and function, and help to identify substitutions that may lead to desired changes in enzyme kinetics. Rubisco, the most abundant enzyme in biosphere, plays an essential role in the process of carbon fixation through photosynthesis, thus facilitating life on Earth. This makes Rubisco an important model system for studying the dynamics of protein fitness optimization on the evolutionary landscape. In this study we investigated the selective and coevolutionary forces acting on large subunit of land plants Rubisco using Markov models of codon substitution and clustering approaches applied to amino acid substitution histories. Results We found that both selection and coevolution shape Rubisco, and that positively selected and coevolving residues have their specifically favored amino acid composition and pairing preference. The mapping of these residues on the known Rubisco tertiary structures showed that the coevolving residues tend to be in closer proximity with each other compared to the background, while positively selected residues tend to be further away from each other. This study also reveals that the residues under positive selection or coevolutionary force are located within functionally important regions and that some residues are targets of both positive selection and coevolution at the same time. Conclusion Our results demonstrate that coevolution of residues is common in Rubisco of land plants and that there is an overlap between coevolving and positively selected residues. Knowledge of which Rubisco residues are coevolving and positively selected could be used for further work on structural modeling and identification of substitutions that may be changed in order to improve efficiency of this important enzyme in crops.

  2. Residues of the UL25 Protein of Herpes Simplex Virus That Are Required for Its Stable Interaction with Capsids ▿

    Science.gov (United States)

    Cockrell, Shelley K.; Huffman, Jamie B.; Toropova, Katerina; Conway, James F.; Homa, Fred L.

    2011-01-01

    The herpes simplex virus 1 (HSV-1) UL25 gene product is a minor capsid component that is required for encapsidation, but not cleavage, of replicated viral DNA. UL25 is located on the capsid surface in a proposed heterodimer with UL17, where five copies of the heterodimer are found at each of the capsid vertices. Previously, we demonstrated that amino acids 1 to 50 of UL25 are essential for its stable interaction with capsids. To further define the UL25 capsid binding domain, we generated recombinant viruses with either small truncations or amino acid substitutions in the UL25 N terminus. Studies of these mutants demonstrated that there are two important regions within the capsid binding domain. The first 27 amino acids are essential for capsid binding of UL25, while residues 26 to 39, which are highly conserved in the UL25 homologues of other alphaherpesviruses, were found to be critical for stable capsid binding. Cryo-electron microscopy reconstructions of capsids containing either a small tag on the N terminus of UL25 or the green fluorescent protein (GFP) fused between amino acids 50 and 51 of UL25 demonstrate that residues 1 to 27 of UL25 contact the hexon adjacent to the penton. A second region, most likely centered on amino acids 26 to 39, contacts the triplex that is one removed from the penton. Importantly, both of these UL25 capsid binding regions are essential for the stable packaging of full-length viral genomes. PMID:21411517

  3. 40 CFR 180.1023 - Propanoic acid; exemptions from the requirement of a tolerance.

    Science.gov (United States)

    2010-07-01

    ...) Propanoic acid is exempt from the requirement of a tolerance for residues in or on cattle, meat; cattle, meat byproducts; goat, meat; goat, meat byproducts; hog, meat; hog meat byproducts; horse, meat; horse, meat byproducts; sheep, meat; sheep meat byproducts; and, poultry, fat; poultry meat; poultry meat...

  4. A Mineralogical Assessment on Residues after Acidic Leaching of Bauxite Residue (Red Mud for Titanium Recovery

    Directory of Open Access Journals (Sweden)

    Gözde Alkan

    2017-10-01

    Full Text Available Due to its alkalinity, red mud produced by the Bayer process may affect both the environment and human health. For this reason, its further utilization instead of disposal is of great importance. Numerous methods have already been studied for hydrometallurgical treatment of red mud, especially for the recovery of various metallic components such as iron, aluminum, titanium or rare earth elements. This study focuses on the extraction of titanium from red mud and in particular the mineralogical changes, induced by leaching. Sulfuric acid, hydrochloric acid and their combination have been utilized as leaching agents with the same leaching parameters. It has been determined that sulfuric acid is the best candidate for the red mud treatment in terms of titanium leaching efficiency at the end of 2 h with a value of 67.3%. Moreover, samples from intermediate times of reaction revealed that leaching of Ti exhibit various reaction rates at different times of reaction depending on acid type. In order to explain differences, X-ray Diffraction (XRD, scanning electron microscope (SEM and QEMSCAN techniques were utilized. Beside titanium oxide (TiO2 with available free surface area, a certain amount of the TiO2 was detected as entrapped in Fe dominating oxide. These associations between Ti and Fe phases were used to explain different leaching reaction rates and a reaction mechanism was proposed to open a process window.

  5. Activity of boric acid on German cockroaches: Analysis of residues ...

    African Journals Online (AJOL)

    STORAGESEVER

    2009-02-18

    Feb 18, 2009 ... Full Length Research Paper. Activity of ... In a previous study, we have shown that boric ... ing 300 µl of curcumin solution (12.5 mg curcumin, 10 ml acetic acid) ..... Schal C, Chiang AS, Burns EL, Gadot M, Cooper RA (1993).

  6. Studies on distribution and residue of sulfur in simulated acid rain in vegetable and soil by using 35S

    International Nuclear Information System (INIS)

    Wan Zhaoliang; Liu Dayong

    1995-01-01

    Distribution and residue of sulfur in simulated acid rain in two kinds of vegetables (lettuce and Chinese cabbage) and three types of soils (acid yellow earth, acid and neutral purple soils) were studied by using 35 S tracer method. The results showed that the higher concentration of acid rain was sprayed, the more residue of sulfur in vegetable there would be. The residue of sulfur in vegetable varied with the different physical and chemical properties of soils, the order of sulfur residue in vegetable was: acid purple soil>acid yellow earth>neutral purple soil. In the same soil, the residue of sulfur in lettuce was higher than that in Chinese cabbage, for the same vegetable, the residue of sulfur in leaves were higher than that in stems. The order of sulfur residue in different soils was acid purple soil>acid yellow earth>neutral purple soil. The higher concentration of acid rain was sprayed, the more residue of sulfur in soil surface there would be. The sulfur residue varied with the depth of soil and the pH value of acid rain. With the increase of soil depth, a slight increase of sulfur residue with rain of ph 6 and a slight decrease with rain of pH 4.0 and 2.5 were found

  7. Computational studies on non-succinimide-mediated stereoinversion mechanism of aspartic acid residues assisted by phosphate

    Science.gov (United States)

    Nakayoshi, Tomoki; Fukuyoshi, Shuichi; Takahashi, Ohgi; Oda, Akifumi

    2018-03-01

    Although nearly all of the amino acids that constitute proteins are l-amino acids, d-amino acid residues in human proteins have been recently reported. d-amino acid residues cause a change in the three-dimensional structure of proteins, and d-aspartic acid (Asp) residues are considered to be one of the causes of age-related diseases. The stereoinversion of Asp residues in peptides and proteins is thought to proceed via a succinimide intermediate; however, it has been reported that stereoinversion can occur even under conditions where a succinimide intermediate cannot be formed. In order to elucidate the non-succinimide-mediated stereoinversion pathway, we investigated the stereoinversion of l-Asp to d-Asp catalysed by phosphate and estimated the activation barrier using B3LYP/6-31+G(d,p) density functional theory (DFT) calculations. For the DFT calculations, a model compound in which the Asp residue is capped with acetyl and methyl-amino groups on the N- and C-termini, respectively, was used. The calculated activation barrier was not excessively high for the stereoinversion to occur in vivo. Therefore, this stereoinversion mechanism may compete with the succinimide-mediated mechanism.

  8. Preparation and Characterization of a Solid Acid Catalyst from Macro Fungi Residue for Methyl Palmitate Production

    Directory of Open Access Journals (Sweden)

    Min Wang

    2015-07-01

    Full Text Available During the process of fungal polysaccharide extraction for health care products and food factories, a large quantity of macro-fungi residues are produced, but most of the residues are abandoned and become environmental pollutants. A solid acid catalyst, prepared by sulfonating carbonized Phellinus igniarius residue, was shown to be an efficient and environmentally benign catalyst for the esterification of palmitate acid (PA and methanol. As a comparison, two types of common biomass catalysts, wheat straws and wood chips, were prepared. In this study, characterizations, including scanning electron microscopy, thermo-gravimetric analysis, Fourier transform infrared spectrometry, Brunauer-Emmett-Teller assays and elemental analysis, and reaction conditions for the synthesis of methyl palmitate (MP using solid acid catalysts were investigated. Experiments showed that the solid acid catalyst prepared from P. igniarius residue had a higher catalytic activity than the other two catalysts, and the highest yield of MP catalyzed by P. igniarius residue solid acid catalyst was 91.5% under the following optimum conditions: molar ratio of methanol/PA of 10:1, reaction temperature of 60 °C, mass ratio of catalyst/substrate of 2%, and a reaction time of 1.5 h. Thus, the use of this catalyst offers a method for producing MP.

  9. Temperature-dependent dynamical transitions of different classes of amino acid residue in a globular protein.

    Science.gov (United States)

    Miao, Yinglong; Yi, Zheng; Glass, Dennis C; Hong, Liang; Tyagi, Madhusudan; Baudry, Jerome; Jain, Nitin; Smith, Jeremy C

    2012-12-05

    The temperature dependences of the nanosecond dynamics of different chemical classes of amino acid residue have been analyzed by combining elastic incoherent neutron scattering experiments with molecular dynamics simulations on cytochrome P450cam. At T = 100-160 K, anharmonic motion in hydrophobic and aromatic residues is activated, whereas hydrophilic residue motions are suppressed because of hydrogen-bonding interactions. In contrast, at T = 180-220 K, water-activated jumps of hydrophilic side chains, which are strongly coupled to the relaxation rates of the hydrogen bonds they form with hydration water, become apparent. Thus, with increasing temperature, first the hydrophobic core awakens, followed by the hydrophilic surface.

  10. Residual learning rates in lead-acid batteries: Effects on emerging technologies

    International Nuclear Information System (INIS)

    Matteson, Schuyler; Williams, Eric

    2015-01-01

    The low price of lead-acid, the most popular battery, is often used in setting cost targets for emerging energy storage technologies. Future cost reductions in lead acid batteries could increase investment and time scales needed for emerging storage technologies to reach cost-parity. In this paper the first documented model of cost reductions for lead-acid batteries is developed. Regression to a standard experience curve using 1989–2012 data yield a poor fit, with R 2 values of 0.17 for small batteries and 0.05 for larger systems. To address this problem, battery costs are separated into material and residual costs, and experience curves developed for residual costs. Depending on the year, residual costs account for 41–86% of total battery cost. Using running-time averages to address volatility in material costs, a 4-year time average experience curve for residual costs yield much higher R 2 , 0.78 for small and 0.74 for large lead-acid batteries. The learning rate for residual costs in lead-acid batteries is 20%, a discovery with policy implications. Neglecting to consider cost reductions in lead-acid batteries could result in failure of energy storage start-ups and public policy programs. Generalizing this result, learning in incumbent technologies must be understood to assess the potential of emerging ones. -- Highlights: •We analyze potential cost reductions in lead-acid batteries. •Modified experience curve for non-material costs gives good empirical fit. •Historical learning rate for non-material costs from 1985–2012 is 19–24%. •Progress in incumbent technology raises barrier to new entrants

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

    Science.gov (United States)

    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

  12. Maximizing Selective Cleavages at Aspartic Acid and Proline Residues for the Identification of Intact Proteins

    Science.gov (United States)

    Foreman, David J.; Dziekonski, Eric T.; McLuckey, Scott A.

    2018-04-01

    A new approach for the identification of intact proteins has been developed that relies on the generation of relatively few abundant products from specific cleavage sites. This strategy is intended to complement standard approaches that seek to generate many fragments relatively non-selectively. Specifically, this strategy seeks to maximize selective cleavage at aspartic acid and proline residues via collisional activation of precursor ions formed via electrospray ionization (ESI) under denaturing conditions. A statistical analysis of the SWISS-PROT database was used to predict the number of arginine residues for a given intact protein mass and predict a m/z range where the protein carries a similar charge to the number of arginine residues thereby enhancing cleavage at aspartic acid residues by limiting proton mobility. Cleavage at aspartic acid residues is predicted to be most favorable in the m/z range of 1500-2500, a range higher than that normally generated by ESI at low pH. Gas-phase proton transfer ion/ion reactions are therefore used for precursor ion concentration from relatively high charge states followed by ion isolation and subsequent generation of precursor ions within the optimal m/z range via a second proton transfer reaction step. It is shown that the majority of product ion abundance is concentrated into cleavages C-terminal to aspartic acid residues and N-terminal to proline residues for ions generated by this process. Implementation of a scoring system that weights both ion fragment type and ion fragment area demonstrated identification of standard proteins, ranging in mass from 8.5 to 29.0 kDa. [Figure not available: see fulltext.

  13. Dynamics of Linker Residues Modulate the Nucleic Acid Binding Properties of the HIV-1 Nucleocapsid Protein Zinc Fingers

    Science.gov (United States)

    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. PMID:25029439

  14. Biosynthesis of D-alanyl-lipoteichoic acid by Lactobacillus casei: interchain transacylation of D-alanyl ester residues

    International Nuclear Information System (INIS)

    Childs, W.C. III; Taron, D.J.; Neuhaus, F.C.

    1985-01-01

    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-[ 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

  15. Process Design Aspects for Scandium-Selective Leaching of Bauxite Residue with Sulfuric Acid

    OpenAIRE

    Konstantinos Hatzilyberis; Theopisti Lymperopoulou; Lamprini-Areti Tsakanika; Klaus-Michael Ochsenkühn; Paraskevas Georgiou; Nikolaos Defteraios; Fotios Tsopelas; Maria Ochsenkühn-Petropoulou

    2018-01-01

    Aiming at the industrial scale development of a Scandium (Sc)-selective leaching process of Bauxite Residue (BR), a set of process design aspects has been investigated. The interpretation of experimental data for Sc leaching yield, with sulfuric acid as the leaching solvent, has shown significant impact from acid feed concentration, mixing time, liquid to solids ratio (L/S), and number of cycles of leachate re-usage onto fresh BR. The thin film diffusion model, as the fundamental theory for l...

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

    Science.gov (United States)

    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.)

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

    Directory of Open Access Journals (Sweden)

    Kazutaka Sawada

    2016-01-01

    Full Text Available 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.

  18. Natively oxidized amino acid residues in the spinach cytochrome b 6 f complex.

    Science.gov (United States)

    Taylor, Ryan M; Sallans, Larry; Frankel, Laurie K; Bricker, Terry M

    2018-01-29

    The cytochrome b 6 f complex of oxygenic photosynthesis produces substantial levels of reactive oxygen species (ROS). It has been observed that the ROS production rate by b 6 f is 10-20 fold higher than that observed for the analogous respiratory cytochrome bc 1 complex. The types of ROS produced (O 2 •-, 1 O 2 , and, possibly, H 2 O 2 ) and the site(s) of ROS production within the b 6 f complex have been the subject of some debate. Proposed sources of ROS have included the heme b p , PQ p •- (possible sources for O 2 •- ), the Rieske iron-sulfur cluster (possible source of O 2 •- and/or 1 O 2 ), Chl a (possible source of 1 O 2 ), and heme c n (possible source of O 2 •- and/or H 2 O 2 ). Our working hypothesis is that amino acid residues proximal to the ROS production sites will be more susceptible to oxidative modification than distant residues. In the current study, we have identified natively oxidized amino acid residues in the subunits of the spinach cytochrome b 6 f complex. The oxidized residues were identified by tandem mass spectrometry using the MassMatrix Program. Our results indicate that numerous residues, principally localized near p-side cofactors and Chl a, were oxidatively modified. We hypothesize that these sites are sources for ROS generation in the spinach cytochrome b 6 f complex.

  19. Identification of amino acid residues in PEPHC1 important for binding to the tumor-specific receptor EGFRvIII

    DEFF Research Database (Denmark)

    Hansen, Charlotte Lund; Hansen, Paul Robert; Pedersen, Nina

    2008-01-01

    to identify the amino acid residues important for binding of PEPHC1 to EGFRvIII. The results indicate that the amino acid residues at the N-terminus of PEPHC1 are essential for the binding to the mutated receptor. One analog, [Ala(12)]PEPHC1, showed higher selective binding to EGFRvIII than PEPHC1...

  20. Physicochemical pretreatments and hydrolysis of furfural residues via carbon-based sulfonated solid acid.

    Science.gov (United States)

    Ma, Bao Jun; Sun, Yuan; Lin, Ke Ying; Li, Bing; Liu, Wan Yi

    2014-03-01

    Potential commercial physicochemical pretreatment methods, NaOH/microwave and NaOH/ultrasound were developed, and the carbon-based sulfonated solid acid catalysts were prepared for furfural residues conversion into reducing sugars. After the two optimum pretreatments, both the content of cellulose increased (74.03%, 72.28%, respectively) and the content of hemicellulose (94.11%, 94.17% of removal rate, respectively) and lignin (91.75%, 92.09% of removal rate, respectively) decreased in furfural residues. The reducing sugar yields of furfural residues with the two physicochemical pretreatments on coal tar-based solid acid reached 33.94% and 33.13%, respectively, higher than that pretreated via NaOH alone (27%) and comparable to that pretreated via NaOH/H2O2 (35.67%). The XRD patterns, IR spectra and SEM images show microwave and ultrasound improve the pretreatment effect. The results demonstrate the carbon-based sulfonated solid acids and the physicochemical pretreatments are green, effective, low-cost for furfural residues conversion. Copyright © 2014 Elsevier Ltd. All rights reserved.

  1. Amino acid residues involved in ligand preference of the Snf3 transporter-like sensor in Saccharomyces cerevisiae

    DEFF Research Database (Denmark)

    Dietvorst, J.; Karhumaa, Kaisa; Kielland-Brandt, Morten

    2010-01-01

    /preferences of Snf3. The ability of cells to sense sugars in vivo was monitored by following the degradation of the Mth1 protein, :ill earl., event ill the signal pathway. Our study reveals that Snf3. ill addition to glucose. also senses fructose and mannose, as well as the glucose analogues 2-deoxyglucose, 3-O......-methylglucoside and 6-deoxyglucose. The signalling proficiency of a non-phosphorylatable analogue strongly supports the notion that sensing through Snf3 does not require sugar phosphorylation. Sequence comparisons of Snf3 to glucose transporters indicated amino acid residues possibly involved in sensing of sugars other...... than glucose. By site-specific mutagenesis of the structural gene, roles of specific residues in Snf3 could he established. Change of isoleucine-374 to valine ill transmembrane segment 7 of Snf3 partially abolished sensing of fructose mannose. while mutagenesis causing it change of phenylalanine-462 (4...

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

    Science.gov (United States)

    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.

  3. Antimicrobial residual effects of irrigation regimens with maleic acid in infected root canals

    OpenAIRE

    Ferrer-Luque, Carmen Mar?a; Gonz?lez-Castillo, Silvia; Ruiz-Linares, Matilde; Arias-Moliz, Mar?a Teresa; Rodr?guez-Archilla, Alberto; Baca, Pilar

    2015-01-01

    Background The success of endodontic treatment depends largely on the control of microorganisms present in infected root canals. The aim of this study was to determine the residual antimicrobial activity of several final irrigation protocols with 7% maleic acid (MA) alone and combined with chlorhexidine (CHX), cetrimide (CTR) or both, in root canals infected with Enterococcus faecalis. Biofilms of E. faecalis were grown in uniradicular roots for 4 weeks. A total of 72 specimens were divided i...

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

    Directory of Open Access Journals (Sweden)

    Ohgi Takahashi

    2015-01-01

    Full Text Available 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.

  5. Acetic acid can catalyze succinimide formation from aspartic acid residues by a concerted bond reorganization mechanism: a computational study.

    Science.gov (United States)

    Takahashi, Ohgi; Kirikoshi, Ryota; Manabe, Noriyoshi

    2015-01-12

    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.

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

    Directory of Open Access Journals (Sweden)

    Chaline Caren Coghetto

    Full Text Available Abstract 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 17.87 g L-1, whereas lactic acid, the most important lactic acid bacteria metabolite, peaked at 37.59 g L-1, corresponding to a productivity of 1.46 g L-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.

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

    Science.gov (United States)

    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. Copyright © 2016 Sociedade Brasileira de Microbiologia. Published by Elsevier Editora Ltda. All rights reserved.

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

    Science.gov (United States)

    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. Copyright © 2013 Elsevier Ltd. All rights reserved.

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

    Science.gov (United States)

    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 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 acid residues compared with B/I, which mainly explains the apparent differences in molecular weight. Future investigations will focus on the clinical and functional significance of the revealed differences in sialic acid residues.

  10. Characteristics of lactic acid bacteria isolates and their effect on silage fermentation of fruit residues.

    Science.gov (United States)

    Yang, Jinsong; Tan, Haisheng; Cai, Yimin

    2016-07-01

    The natural lactic acid bacteria (LAB) population, chemical composition, and silage fermentation of fruit residues were studied. Eighty-two strains of LAB were isolated from fruit residues such as banana leaf and stem, pineapple peel, and papaya peel. All strains were gram-positive and catalase-negative bacteria, and they were divided into 7 groups (A-G) according to morphological and biochemical characters. Strains in groups A to F were rods, and group G was cocci. Group F produced gas from glucose; other groups did not. Groups A to C and F formed dl-lactic acid, whereas groups D, E, and G formed l-lactic acid. Based on the 16S rRNA gene sequence and DNA-DNA hybridization analysis, groups A to G strains were identified as Lactobacillus plantarum (54.9% of the total isolates), Lactobacillus paraplantarum (3.6%), Lactobacillus nagelii (8.5%), Lactobacillus perolens (4.9%), Lactobacillus casei (11.0%), Lactobacillus fermentum (9.8%), and Enterococcus gallinarum (7.3%), respectively. Lactobacillus plantarum and Lactobacillus casei are the most frequently isolated from fruit residues as a dominant species, and they could grow at a lower pH conditions and produce more lactic acid than other isolates. Pineapple and papaya peels contained higher crude protein (11.5-13.8%) and water-soluble carbohydrate (16.8-22.4%), but lower acid detergent fiber contents (21.2 to 26.4%) than banana stems and leaves (8.2% crude protein, 42.8% acid detergent fiber, and 5.1% water-soluble carbohydrate). Compared with banana stem and leaf silages, the pineapple and papaya peel silages were well preserved with a lower pH and higher lactate content. The study suggests that the fruit residues contain excellent LAB species and abundant feed nutrients, and that they can be preserved as silage to be potential food resources for livestock. Copyright © 2016 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

  11. Composition, texture and methane potential of cellulosic residues from Lewis acids organosolv pulping of wheat straw.

    Science.gov (United States)

    Constant, Sandra; Barakat, Abdellatif; Robitzer, Mike; Di Renzo, Francesco; Dumas, Claire; Quignard, Françoise

    2016-09-01

    Cellulosic pulps have been successfully isolated from wheat straw through a Lewis acids organosolv treatment. The use of Lewis acids with different hardness produced pulps with different delignification degrees. The cellulosic residue was characterised by chemical composition, X-ray diffraction, FT-IR spectroscopy, N2 physisorption, scanning electron microscopy and potential for anaerobic digestibility. Surface area and pore volume increased with the hardness of the Lewis acid, in correspondence with the decrease of the amount of lignin and hemicellulose in the pulp. The non linearity of the correlation between porosity and composition suggests that an agglomeration of cellulose fibrils occurs in the early stages of pulping. All organosolv pulps presented a significantly higher methane potential than the parent straw. A methane evolution of 295Ncm(3)/g OM was reached by a moderate improvement of the accessibility of the native straw. Copyright © 2016 Elsevier Ltd. All rights reserved.

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

    Science.gov (United States)

    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. Copyright © 2013. Published by Elsevier Ltd.

  13. SNBRFinder: A Sequence-Based Hybrid Algorithm for Enhanced Prediction of Nucleic Acid-Binding Residues.

    Science.gov (United States)

    Yang, Xiaoxia; Wang, Jia; Sun, Jun; Liu, Rong

    2015-01-01

    Protein-nucleic acid interactions are central to various fundamental biological processes. Automated methods capable of reliably identifying DNA- and RNA-binding residues in protein sequence are assuming ever-increasing importance. The majority of current algorithms rely on feature-based prediction, but their accuracy remains to be further improved. Here we propose a sequence-based hybrid algorithm SNBRFinder (Sequence-based Nucleic acid-Binding Residue Finder) by merging a feature predictor SNBRFinderF and a template predictor SNBRFinderT. SNBRFinderF was established using the support vector machine whose inputs include sequence profile and other complementary sequence descriptors, while SNBRFinderT was implemented with the sequence alignment algorithm based on profile hidden Markov models to capture the weakly homologous template of query sequence. Experimental results show that SNBRFinderF was clearly superior to the commonly used sequence profile-based predictor and SNBRFinderT can achieve comparable performance to the structure-based template methods. Leveraging the complementary relationship between these two predictors, SNBRFinder reasonably improved the performance of both DNA- and RNA-binding residue predictions. More importantly, the sequence-based hybrid prediction reached competitive performance relative to our previous structure-based counterpart. Our extensive and stringent comparisons show that SNBRFinder has obvious advantages over the existing sequence-based prediction algorithms. The value of our algorithm is highlighted by establishing an easy-to-use web server that is freely accessible at http://ibi.hzau.edu.cn/SNBRFinder.

  14. Critical lysine residues of Klf4 required for protein stabilization and degradation

    Energy Technology Data Exchange (ETDEWEB)

    Lim, Key-Hwan; Kim, So-Ra; Ramakrishna, Suresh; Baek, Kwang-Hyun, E-mail: baek@cha.ac.kr

    2014-01-24

    Highlights: • Klf4 undergoes the 26S proteasomal degradation by ubiquitination on its multiple lysine residues. • Essential Klf4 ubiquitination sites are accumulated between 190–263 amino acids. • A mutation of lysine at 232 on Klf4 elongates protein turnover. • Klf4 mutants dramatically suppress p53 expression both under normal and UV irradiated conditions. - Abstract: The transcription factor, Krüppel-like factor 4 (Klf4) plays a crucial role in generating induced pluripotent stem cells (iPSCs). As the ubiquitination and degradation of the Klf4 protein have been suggested to play an important role in its function, the identification of specific lysine sites that are responsible for protein degradation is of prime interest to improve protein stability and function. However, the molecular mechanism regulating proteasomal degradation of the Klf4 is poorly understood. In this study, both the analysis of Klf4 ubiquitination sites using several Klf4 deletion fragments and bioinformatics predictions showed that the lysine sites which are signaling for Klf4 protein degradation lie in its N-terminal domain (aa 1–296). The results also showed that Lys32, 52, 232, and 252 of Klf4 are responsible for the proteolysis of the Klf4 protein. These results suggest that Klf4 undergoes proteasomal degradation and that these lysine residues are critical for Klf4 ubiquitination.

  15. Fatty acids are required for epidermal permeability barrier function.

    Science.gov (United States)

    Mao-Qiang, M; Elias, P M; Feingold, K R

    1993-08-01

    The permeability barrier is mediated by a mixture of ceramides, sterols, and free fatty acids arranged as extracellular lamellar bilayers in the stratum corneum. Whereas prior studies have shown that cholesterol and ceramides are required for normal barrier function, definitive evidence for the importance of nonessential fatty acids is not available. To determine whether epidermal fatty acid synthesis also is required for barrier homeostasis, we applied 5-(tetradecyloxy)-2-furancarboxylic acid (TOFA), an inhibitor of acetyl CoA carboxylase, after disruption of the barrier by acetone or tape stripping. TOFA inhibits epidermal fatty acid by approximately 50% and significantly delays barrier recovery. Moreover, coadministration of palmitate with TOFA normalizes barrier recovery, indicating that the delay is due to a deficiency in bulk fatty acids. Furthermore, TOFA treatment also delays the return of lipids to the stratum corneum and results in abnormalities in the structure of lamellar bodies, the organelle which delivers lipid to the stratum corneum. In addition, the organization of secreted lamellar body material into lamellar bilayers within the stratum corneum interstices is disrupted by TOFA treatment. Finally, these abnormalities in lamellar body and stratum corneum membrane structure are corrected by coapplication of palmitate with TOFA. These results demonstrate a requirement for bulk fatty acids in barrier homeostasis. Thus, inhibiting the epidermal synthesis of any of the three key lipids that form the extracellular, lipid-enriched membranes of the stratum corneum results in an impairment in barrier homeostasis.

  16. The role of aspartic acid residues 405 and 416 of the kidney isotype of sodium-bicarbonate cotransporter 1 in its targeting to the plasma membrane

    Science.gov (United States)

    Kucher, Volodymyr; Li, Emily Y.; Conforti, Laura; Zahedi, Kamyar A.

    2012-01-01

    The NH2 terminus of the sodium-bicarbonate cotransporter 1 (NBCe1) plays an important role in its targeting to the plasma membrane. To identify the amino acid residues that contribute to the targeting of NBCe1 to the plasma membrane, polarized MDCK cells were transfected with expression constructs coding for green fluorescent protein (GFP)-tagged NBCe1 NH2-terminal deletion mutants, and the localization of GFP-tagged proteins was analyzed by confocal microscopy. Our results indicate that the amino acids between residues 399 and 424 of NBCe1A contain important sequences that contribute to its localization to the plasma membrane. Site-directed mutagenesis studies showed that GFP-NBCe1A mutants D405A and D416A are retained in the cytoplasm of the polarized MDCK epithelial cells. Examination of functional activities of D405A and D416A reveals that their activities are reduced compared with the wild-type NBCe1A. Similarly, aspartic acid residues 449 and 460 of pancreatic NBCe1 (NBCe1B), which correspond to residues 405 and 416 of NBCe1A, are also required for its full functional activity and accurate targeting to the plasma membrane. In addition, while replacement of D416 with glutamic acid did not affect the targeting or functional activity of NBCe1A, substitution of D405 with glutamic acid led to the retention of the mutated protein in the intracellular compartment and impaired functional activity. These studies demonstrate that aspartic acid residues 405 and 416 in the NH2 terminus of NBCe1A are important in its accurate targeting to the plasma membrane. PMID:22442137

  17. Identifying SARS-CoV membrane protein amino acid residues linked to virus-like particle assembly.

    Directory of Open Access Journals (Sweden)

    Ying-Tzu Tseng

    Full Text Available Severe acute respiratory syndrome coronavirus (SARS-CoV membrane (M proteins are capable of self-assembly and release in the form of membrane-enveloped vesicles, and of forming virus-like particles (VLPs when coexpressed with SARS-CoV nucleocapsid (N protein. According to previous deletion analyses, M self-assembly involves multiple M sequence regions. To identify important M amino acid residues for VLP assembly, we coexpressed N with multiple M mutants containing substitution mutations at the amino-terminal ectodomain, carboxyl-terminal endodomain, or transmembrane segments. Our results indicate that a dileucine motif in the endodomain tail (218LL219 is required for efficient N packaging into VLPs. Results from cross-linking VLP analyses suggest that the cysteine residues 63, 85 and 158 are not in close proximity to the M dimer interface. We noted a significant reduction in M secretion due to serine replacement for C158, but not for C63 or C85. Further analysis suggests that C158 is involved in M-N interaction. In addition to mutations of the highly conserved 107-SWWSFNPE-114 motif, substitutions at codons W19, W57, P58, W91, Y94 or F95 all resulted in significantly reduced VLP yields, largely due to defective M secretion. VLP production was not significantly affected by a tryptophan replacement of Y94 or F95 or a phenylalanine replacement of W19, W57 or W91. Combined, these results indicate the involvement of specific M amino acids during SARS-CoV virus assembly, and suggest that aromatic residue retention at specific positions is critical for M function in terms of directing virus assembly.

  18. Study on residual discharge time of lead-acid battery based on fitting method

    Science.gov (United States)

    Liu, Bing; Yu, Wangwang; Jin, Yueqiang; Wang, Shuying

    2017-05-01

    This paper use the method of fitting to discuss the data of C problem of mathematical modeling in 2016, the residual discharge time model of lead-acid battery with 20A,30A,…,100A constant current discharge is obtained, and the discharge time model of discharge under arbitrary constant current is presented. The mean relative error of the model is calculated to be about 3%, which shows that the model has high accuracy. This model can provide a basis for optimizing the adaptation of power system to the electrical motor vehicle.

  19. DNA Three Way Junction Core Decorated with Amino Acids-Like Residues-Synthesis and Characterization

    Directory of Open Access Journals (Sweden)

    Claudia Addamiano

    2016-08-01

    Full Text Available Construction and physico-chemical behavior of DNA three way junction (3WJ functionalized by protein-like residues (imidazole, alcohol and carboxylic acid at unpaired positions at the core is described. One 5′-C(S-propargyl-thymidine nucleotide was specifically incorporated on each strand to react through a post synthetic CuACC reaction with either protected imidazolyl-, hydroxyl- or carboxyl-azide. Structural impacts of 5′-C(S-functionalization were investigated to evaluate how 3WJ flexibility/stability is affected.

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

    Directory of Open Access Journals (Sweden)

    Michał Jewgiński

    2014-03-01

    Full Text Available 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.

  1. Lead Isotope Compositions of Acid Residues from Olivine-Phyric Shergottite Tissint: Implications for Heterogeneous Shergottite Source Reservoirs

    Science.gov (United States)

    Moriwaki, R.; Usui, T.; Yokoyama, T.; Simon, J. I.; Jones, J. H.

    2015-01-01

    Geochemical studies of shergottites suggest that their parental magmas reflect mixtures between at least two distinct geochemical source reservoirs, producing correlations between radiogenic isotope compositions and trace element abundances. These correlations have been interpreted as indicating the presence of a reduced, incompatible element- depleted reservoir and an oxidized, incompatible- element-enriched reservoir. The former is clearly a depleted mantle source, but there is ongoing debate regarding the origin of the enriched reservoir. Two contrasting models have been proposed regarding the location and mixing process of the two geochemical source reservoirs: (1) assimilation of oxidized crust by mantle derived, reduced magmas, or (2) mixing of two distinct mantle reservoirs during melting. The former requires the ancient Martian crust to be the enriched source (crustal assimilation), whereas the latter requires isolation of a long-lived enriched mantle domain that probably originated from residual melts formed during solidification of a magma ocean (heterogeneous mantle model). This study conducts Pb isotope and trace element concentration analyses of sequential acid-leaching fractions (leachates and the final residues) from the geochemically depleted olivine-phyric shergottite Tissint. The results suggest that the Tissint magma is not isotopically uniform and sampled at least two geochemical source reservoirs, implying that either crustal assimilation or magma mixing would have played a role in the Tissint petrogenesis.

  2. Preparation of Grinding Aid Using Waste Acid Residue from Plasticizer Plant

    Science.gov (United States)

    Li, Lingxiao; Feng, Yanchao; Liu, Manchao; Zhao, Fengqing

    2017-09-01

    The grinding aid for granulated blast-furnace slag were prepared from waste acid residue from plasticizer plant through neutralization, de-methanol and granulation process. In this process, sulfuric acid was transformed into gypsum which has much contribution for grinding effect by combined use with the glycerol and poly glycerin in the waste. Fly ash was used for granulation for the composite grinding aid. Methanol can be recycled in the process. The result showed that the suitable addition of grinding aid is 0.03 % of granulated blast-furnace slag (mass). In this case, the specific surface area is 14% higher than that of the blank. Compared with the common grinding aids, it has excellent performance and low cost.

  3. Chlorination of tyrosyl residues in peptides and proteins by hypochlorous acid

    International Nuclear Information System (INIS)

    Kettle, A.J.; Chapman, A.L.P.; Senthilmohan, R.; Vile, G.F.; Chai, L.L.

    1998-01-01

    Full text: Hypochlorous acid (HOCI) is the major strong oxidant produced by neutrophils. These granulocytic cells use HOCI to kill bacteria and it is also proposed to promote inflammation. Previously, it was shown that HOCI converts tyrosyl residues in proteins to 3-chlorotyrosine. This chlorinated molecule is an ideal biomarker for determining the precise roles HOCI plays in bacterial killing and inflammatory tissue damage. We have investigated the reaction of HOCI with tyrosyl residues in peptides and proteins to establish whether or not chlorinated products in addition to 3-chlorotyrosine are formed. When 200μM HOCI was added to 500μg/ml of bovine serum albumin both 3-chlorotyrosine and 3,5-dichlorotyrosine were formed. The monochlorinated amino acid was the predominant product and its formation was complete by 20 minutes whereas levels of 3,5-dichlorotyrosine continued to increase for up to an hour. Amounts of both chlorinated products increased with increasing concentrations of HOCI until a plateau was reached at about 800μM. At all concentrations of HOCI a substantial amount of the tyrosine that had reacted was unaccounted for as either 3-chlorotyrosine or 3,5-dichlorotyrosine. Similar results were obtained with small peptides containing tyrosine. Sub-stoichiometric concentrations of HOCI converted tyrosyl residues in GGYR to 3-chlorotyrosine. At higher concentrations of HOCI, chlorination was rapid and both 3-chlorotyrosine and 3,5-dichlorotyrosine were produced but they accounted for less than 50% of the products. To identify the additional products of the reaction, we reacted HOCI with tyrosine analogues including N-acetyltyrosine, phydroxyphenylacetic acid, and 4-propylphenol. Separation of the reaction mixture by HPLC revealed that numerous products were formed besides mono and dichlorinated derivatives of the parent compounds. Analysis of the products by gas chromatography/mass spectrometry strongly indicated that mono and dichlorinated

  4. [Determination of residual solvents in 7-amino-3-chloro cephalosporanic acid by gas chromatography].

    Science.gov (United States)

    Ma, Li; Yao, Tong-wei

    2011-01-01

    To develop a gas chromatography method for determination of residual solvents in 7-amino-3-chloro cephalosporanic acid (7-ACCA). The residual levels of acetone, methanol, dichloromethane, ethyl acetate, isobutanol, pyridine and toluene in 7-ACCA were measured by gas chromatography using Agilent INNOWAX capillary column (30 m × 0.32 mm,0.5 μm). The initial column temperature was 70° maintained for 6 min and then raised (10°C/min) to 160°C for 1 min. Nitrogen gas was used as carrier and FID as detector. The flow of carrier was 1.0 ml/min, the temperature of injection port and detector was 200°C and 250°C, respectively. The limits of detection for acetone, methanol, dichloromethane, ethyl acetate, isobutanol, pyridine, toluene in 7-ACCA were 2.5 μg/ml, 1.5 μg/ml, 15 μg/ml, 2.5 μg/ml, 2.5 μg/ml, 2.5 μg/ml and 11 μg/ml, respectively. Only acetone was detected in the sample, and was less than the limits of Ch.P. The method can effectively detect the residual solvents in 7-ACCA.

  5. Computational Analysis of the Interaction Energies between Amino Acid Residues of the Measles Virus Hemagglutinin and Its Receptors

    Directory of Open Access Journals (Sweden)

    Fengqi Xu

    2018-05-01

    Full Text Available Measles virus (MV causes an acute and highly devastating contagious disease in humans. Employing the crystal structures of three human receptors, signaling lymphocyte-activation molecule (SLAM, CD46, and Nectin-4, in complex with the measles virus hemagglutinin (MVH, we elucidated computationally the details of binding energies between the amino acid residues of MVH and those of the receptors with an ab initio fragment molecular orbital (FMO method. The calculated inter-fragment interaction energies (IFIEs revealed a number of significantly interacting amino acid residues of MVH that played essential roles in binding to the receptors. As predicted from previously reported experiments, some important amino-acid residues of MVH were shown to be common but others were specific to interactions with the three receptors. Particularly, some of the (non-polar hydrophobic residues of MVH were found to be attractively interacting with multiple receptors, thus indicating the importance of the hydrophobic pocket for intermolecular interactions (especially in the case of Nectin-4. In contrast, the electrostatic interactions tended to be used for specific molecular recognition. Furthermore, we carried out FMO calculations for in silico experiments of amino acid mutations, finding reasonable agreements with virological experiments concerning the substitution effect of residues. Thus, the present study demonstrates that the electron-correlated FMO method is a powerful tool to search exhaustively for amino acid residues that contribute to interactions with receptor molecules. It is also applicable for designing inhibitors of MVH and engineered MVs for cancer therapy.

  6. Identification of key amino acid residues modulating intracellular and in vitro microcin E492 amyloid formation

    Directory of Open Access Journals (Sweden)

    Paulina eAguilera

    2016-01-01

    Full Text Available 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 E. coli cells, that were visualized as round-shaped inclusion bodies recognized by two amyloidophillic 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

  7. Accurate prediction of hot spot residues through physicochemical characteristics of amino acid sequences

    KAUST Repository

    Chen, Peng

    2013-07-23

    Hot spot residues of proteins are fundamental interface residues that help proteins perform their functions. Detecting hot spots by experimental methods is costly and time-consuming. Sequential and structural information has been widely used in the computational prediction of hot spots. However, structural information is not always available. In this article, we investigated the problem of identifying hot spots using only physicochemical characteristics extracted from amino acid sequences. We first extracted 132 relatively independent physicochemical features from a set of the 544 properties in AAindex1, an amino acid index database. Each feature was utilized to train a classification model with a novel encoding schema for hot spot prediction by the IBk algorithm, an extension of the K-nearest neighbor algorithm. The combinations of the individual classifiers were explored and the classifiers that appeared frequently in the top performing combinations were selected. The hot spot predictor was built based on an ensemble of these classifiers and to work in a voting manner. Experimental results demonstrated that our method effectively exploited the feature space and allowed flexible weights of features for different queries. On the commonly used hot spot benchmark sets, our method significantly outperformed other machine learning algorithms and state-of-the-art hot spot predictors. The program is available at http://sfb.kaust.edu.sa/pages/software.aspx. © 2013 Wiley Periodicals, Inc.

  8. Accurate prediction of hot spot residues through physicochemical characteristics of amino acid sequences

    KAUST Repository

    Chen, Peng; Li, Jinyan; Limsoon, Wong; Kuwahara, Hiroyuki; Huang, Jianhua Z.; Gao, Xin

    2013-01-01

    Hot spot residues of proteins are fundamental interface residues that help proteins perform their functions. Detecting hot spots by experimental methods is costly and time-consuming. Sequential and structural information has been widely used in the computational prediction of hot spots. However, structural information is not always available. In this article, we investigated the problem of identifying hot spots using only physicochemical characteristics extracted from amino acid sequences. We first extracted 132 relatively independent physicochemical features from a set of the 544 properties in AAindex1, an amino acid index database. Each feature was utilized to train a classification model with a novel encoding schema for hot spot prediction by the IBk algorithm, an extension of the K-nearest neighbor algorithm. The combinations of the individual classifiers were explored and the classifiers that appeared frequently in the top performing combinations were selected. The hot spot predictor was built based on an ensemble of these classifiers and to work in a voting manner. Experimental results demonstrated that our method effectively exploited the feature space and allowed flexible weights of features for different queries. On the commonly used hot spot benchmark sets, our method significantly outperformed other machine learning algorithms and state-of-the-art hot spot predictors. The program is available at http://sfb.kaust.edu.sa/pages/software.aspx. © 2013 Wiley Periodicals, Inc.

  9. Influences of conformations of peptides on stereoinversions and/or isomerizations of aspartic acid residues.

    Science.gov (United States)

    Oda, Akifumi; Nakayoshi, Tomoki; Fukuyoshi, Shuichi; Kurimoto, Eiji; Takahashi, Ohgi

    2018-07-01

    Recently, non-enzymatic stereoinversions of aspartic acid (Asp) residues in proteins and peptides have been reported. Here, we performed replica exchange molecular dynamics (REMD) simulations of model peptides (exon 6, 26A-1, and 26A-2) extracted from elastin to investigate their structural features, thereby revealing the factor that influences stereoinversions. For REMD trajectories, we calculated distances between carboxyl carbon in Asp and amide nitrogen in the (n + 1) residue (CN distances). Because bond formation between carbon and nitrogen is indispensable to the formation of a succinimide intermediate the distance between them seems to play an important role in stereoinversion. Moreover, we calculated polar surface areas (PSAs) for the trajectories, finding that CN distances and PSA were different for each peptide, with the longest CN distance and smallest PSA observed for exon 6 peptide, where stereoinversion of Asp is the slowest. Although the average CN distance was shorter for exon 26A-1 peptide than for exon 26A-2 peptide, the number of conformations with CN distances acids: biology in the mirror, edited by Dr. Loredano Pollegioni, Dr. Jean-Pierre Mothet and Dr. Molla Gianluca. Copyright © 2018 Elsevier B.V. All rights reserved.

  10. Accurate prediction of hot spot residues through physicochemical characteristics of amino acid sequences.

    Science.gov (United States)

    Chen, Peng; Li, Jinyan; Wong, Limsoon; Kuwahara, Hiroyuki; Huang, Jianhua Z; Gao, Xin

    2013-08-01

    Hot spot residues of proteins are fundamental interface residues that help proteins perform their functions. Detecting hot spots by experimental methods is costly and time-consuming. Sequential and structural information has been widely used in the computational prediction of hot spots. However, structural information is not always available. In this article, we investigated the problem of identifying hot spots using only physicochemical characteristics extracted from amino acid sequences. We first extracted 132 relatively independent physicochemical features from a set of the 544 properties in AAindex1, an amino acid index database. Each feature was utilized to train a classification model with a novel encoding schema for hot spot prediction by the IBk algorithm, an extension of the K-nearest neighbor algorithm. The combinations of the individual classifiers were explored and the classifiers that appeared frequently in the top performing combinations were selected. The hot spot predictor was built based on an ensemble of these classifiers and to work in a voting manner. Experimental results demonstrated that our method effectively exploited the feature space and allowed flexible weights of features for different queries. On the commonly used hot spot benchmark sets, our method significantly outperformed other machine learning algorithms and state-of-the-art hot spot predictors. The program is available at http://sfb.kaust.edu.sa/pages/software.aspx. Copyright © 2013 Wiley Periodicals, Inc.

  11. SNBRFinder: A Sequence-Based Hybrid Algorithm for Enhanced Prediction of Nucleic Acid-Binding Residues.

    Directory of Open Access Journals (Sweden)

    Xiaoxia Yang

    Full Text Available Protein-nucleic acid interactions are central to various fundamental biological processes. Automated methods capable of reliably identifying DNA- and RNA-binding residues in protein sequence are assuming ever-increasing importance. The majority of current algorithms rely on feature-based prediction, but their accuracy remains to be further improved. Here we propose a sequence-based hybrid algorithm SNBRFinder (Sequence-based Nucleic acid-Binding Residue Finder by merging a feature predictor SNBRFinderF and a template predictor SNBRFinderT. SNBRFinderF was established using the support vector machine whose inputs include sequence profile and other complementary sequence descriptors, while SNBRFinderT was implemented with the sequence alignment algorithm based on profile hidden Markov models to capture the weakly homologous template of query sequence. Experimental results show that SNBRFinderF was clearly superior to the commonly used sequence profile-based predictor and SNBRFinderT can achieve comparable performance to the structure-based template methods. Leveraging the complementary relationship between these two predictors, SNBRFinder reasonably improved the performance of both DNA- and RNA-binding residue predictions. More importantly, the sequence-based hybrid prediction reached competitive performance relative to our previous structure-based counterpart. Our extensive and stringent comparisons show that SNBRFinder has obvious advantages over the existing sequence-based prediction algorithms. The value of our algorithm is highlighted by establishing an easy-to-use web server that is freely accessible at http://ibi.hzau.edu.cn/SNBRFinder.

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

    Science.gov (United States)

    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...

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

    Science.gov (United States)

    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

  14. Sulfhydryl oxidation of mutants with cysteine in place of acidic residues in the lactose permease.

    Science.gov (United States)

    Voss, J; Sun, J; Venkatesan, P; Kaback, H R

    1998-06-02

    To examine further the role of charge-pair interactions in the structure and function of lactose permease, Asp237 (helix VII), Asp240 (helix VII), Glu126 (cytoplasmic loop IV/V), Glu269 (helix VIII), and Glu325 (helix X) were replaced individually with Cys in a functional mutant devoid of Cys residues. Each mutant was then oxidized with H2O2 in order to generate a sulfinic and/or sulfonic acid at these positions. Due to the isosteric relationship between aspartate and sulfinate, in particular, and the lower pKa of the sulfinic and sulfonic acid side chains, oxidized derivatives of Cys are useful probes for examining the role of carboxylates. Asp237-->Cys or Asp240-->Cys permease is inactive, as shown previously, but H2O2 oxidation restores activity to an extent similar to that observed when a negative charge is reintroduced by other means. Glu126-->Cys, Glu269-->Cys, or Glu325-->Cys permease is inactive, but oxidation does not restore active lactose transport. The data are consistent with previous observations indicating that Asp237 and Asp240 are not critical for active lactose transport, while Glu126, Glu269, and Glu325 are irreplaceable. Although Glu269-->Cys permease does not transport lactose, the oxidized mutant exhibits significant transport of beta,D-galactosylpyranosyl 1-thio-beta,D-galactopyranoside, a property observed with Glu269-->Asp permease. The observation supports the idea that an acidic residue at position 269 is important for substrate recognition. Finally, oxidized Glu325-->Cys permease catalyzes equilibrium exchange with an apparent pKa of about 6.5, more than a pH unit lower than that observed with Glu325-->Asp permease, thereby providing strong confirmatory evidence that a negative charge at position 325 determines the rate of translocation of the ternary complex between the permease, substrate, and H+.

  15. Intravenous Tranexamic Acid Decreases Allogeneic Transfusion Requirements in Periacetabular Osteotomy.

    Science.gov (United States)

    Bryan, Andrew J; Sanders, Thomas L; Trousdale, Robert T; Sierra, Rafael J

    2016-01-01

    Bernese (Ganz) periacetabular osteotomy is associated with significant blood loss and the need for perioperative transfusion. Tranexamic acid decreases blood loss and minimizes transfusion rates in total joint arthroplasty. However, no reports have described its use in patients undergoing Bernese periacetabular osteotomy. This study reports the use of intravenous tranexamic acid in these patients. The study included 137 patients (150 hips) who underwent isolated periacetabular osteotomy at a single institution between 2003 and 2014. Of these, 68 patients (75 hips) received intravenous tranexamic acid 1 g at the time of incision and 1 g at the time of closure. A group of 69 patients (75 hips) served as control subjects who underwent periacetabular osteotomy without administration of intravenous tranexamic acid. Thromboembolic disease was defined as deep venous thrombosis or pulmonary embolism occurring within 6 weeks of surgery. Outcomes measured included transfusion requirements, pre- and postoperative hemoglobin values, operative times, and thromboembolic disease rates. Aspirin was used as the thromboembolic prophylactic regimen in 95% of patients. The rate of allogeneic transfusion was 0 in the tranexamic acid group compared with 21% in the control group (P=.0001). No significant difference was found in the autologous cell salvage requirement (.96 vs 1.01; P=.43) or the thromboembolic disease rate between the tranexamic acid group and the control group (2.67% vs 1.33%; P=.31). The use of intravenous tranexamic acid led to a decreased transfusion requirement with no increased risk of thromboembolic disease in this contemporary cohort of patients undergoing periacetabular osteotomy. Copyright 2016, SLACK Incorporated.

  16. External pH modulates EAG superfamily K+ channels through EAG-specific acidic residues in the voltage sensor

    Science.gov (United States)

    Kazmierczak, Marcin; Zhang, Xiaofei; Chen, Bihan; Mulkey, Daniel K.; Shi, Yingtang; Wagner, Paul G.; Pivaroff-Ward, Kendra; Sassic, Jessica K.; Bayliss, Douglas A.

    2013-01-01

    The Ether-a-go-go (EAG) superfamily of voltage-gated K+ channels consists of three functionally distinct gene families (Eag, Elk, and Erg) encoding a diverse set of low-threshold K+ currents that regulate excitability in neurons and muscle. Previous studies indicate that external acidification inhibits activation of three EAG superfamily K+ channels, Kv10.1 (Eag1), Kv11.1 (Erg1), and Kv12.1 (Elk1). We show here that Kv10.2, Kv12.2, and Kv12.3 are similarly inhibited by external protons, suggesting that high sensitivity to physiological pH changes is a general property of EAG superfamily channels. External acidification depolarizes the conductance–voltage (GV) curves of these channels, reducing low threshold activation. We explored the mechanism of this high pH sensitivity in Kv12.1, Kv10.2, and Kv11.1. We first examined the role of acidic voltage sensor residues that mediate divalent cation block of voltage activation in EAG superfamily channels because protons reduce the sensitivity of Kv12.1 to Zn2+. Low pH similarly reduces Mg2+ sensitivity of Kv10.1, and we found that the pH sensitivity of Kv11.1 was greatly attenuated at 1 mM Ca2+. Individual neutralizations of a pair of EAG-specific acidic residues that have previously been implicated in divalent block of diverse EAG superfamily channels greatly reduced the pH response in Kv12.1, Kv10.2, and Kv11.1. Our results therefore suggest a common mechanism for pH-sensitive voltage activation in EAG superfamily channels. The EAG-specific acidic residues may form the proton-binding site or alternatively are required to hold the voltage sensor in a pH-sensitive conformation. The high pH sensitivity of EAG superfamily channels suggests that they could contribute to pH-sensitive K+ currents observed in vivo. PMID:23712551

  17. External pH modulates EAG superfamily K+ channels through EAG-specific acidic residues in the voltage sensor.

    Science.gov (United States)

    Kazmierczak, Marcin; Zhang, Xiaofei; Chen, Bihan; Mulkey, Daniel K; Shi, Yingtang; Wagner, Paul G; Pivaroff-Ward, Kendra; Sassic, Jessica K; Bayliss, Douglas A; Jegla, Timothy

    2013-06-01

    The Ether-a-go-go (EAG) superfamily of voltage-gated K(+) channels consists of three functionally distinct gene families (Eag, Elk, and Erg) encoding a diverse set of low-threshold K(+) currents that regulate excitability in neurons and muscle. Previous studies indicate that external acidification inhibits activation of three EAG superfamily K(+) channels, Kv10.1 (Eag1), Kv11.1 (Erg1), and Kv12.1 (Elk1). We show here that Kv10.2, Kv12.2, and Kv12.3 are similarly inhibited by external protons, suggesting that high sensitivity to physiological pH changes is a general property of EAG superfamily channels. External acidification depolarizes the conductance-voltage (GV) curves of these channels, reducing low threshold activation. We explored the mechanism of this high pH sensitivity in Kv12.1, Kv10.2, and Kv11.1. We first examined the role of acidic voltage sensor residues that mediate divalent cation block of voltage activation in EAG superfamily channels because protons reduce the sensitivity of Kv12.1 to Zn(2+). Low pH similarly reduces Mg(2+) sensitivity of Kv10.1, and we found that the pH sensitivity of Kv11.1 was greatly attenuated at 1 mM Ca(2+). Individual neutralizations of a pair of EAG-specific acidic residues that have previously been implicated in divalent block of diverse EAG superfamily channels greatly reduced the pH response in Kv12.1, Kv10.2, and Kv11.1. Our results therefore suggest a common mechanism for pH-sensitive voltage activation in EAG superfamily channels. The EAG-specific acidic residues may form the proton-binding site or alternatively are required to hold the voltage sensor in a pH-sensitive conformation. The high pH sensitivity of EAG superfamily channels suggests that they could contribute to pH-sensitive K(+) currents observed in vivo.

  18. Production of bio-sugar and bioethanol from coffee residue (CR) by acid-chlorite pretreatment.

    Science.gov (United States)

    Kim, Ho Myeong; Choi, Yong-Soo; Lee, Dae-Seok; Kim, Yong-Hwan; Bae, Hyeun-Jong

    2017-07-01

    Nowadays, coffee residue (CR) after roasting is recognized as one of the most useful resources in the world for producing the biofuel and bio-materials. In this study, we evaluated the potential of bio-sugar and bioethanol production from acid-chlorite treated CR. Notably, CR treated three times with acid-chlorite after organic solvent extraction (OSE-3), showed the high monosaccharide content, and the efficient sugar conversion yield compared to the other pretreatment conditions. The OSE-3 (6% substrate loading, w/v) can produce bio-sugar (0.568g/g OSE-3). Also, simultaneous saccharification and fermentation (SSF) produced ethanol (0.266g/g OSE-3), and showed an ethanol conversion yield of 73.8% after a 72-h reaction period. These results suggest that acid-chlorite pretreatment can improve the bio-sugar and bioethanol production of CR by removing the phenolic and brown compounds. Copyright © 2017 Elsevier Ltd. All rights reserved.

  19. Amphoteric surfactants containing ?-hydroxy ester group and an amino acid residue

    Directory of Open Access Journals (Sweden)

    Eissa, A. M. F.

    2006-09-01

    Full Text Available A series of amphoteric surfactants containing α-hydroxy ester group and an amino acid residue were prepared with the addition of epoxy derivatives (which were prepared from epoxidation of alkyl methacrylate to different types of amino acids (glycine, alanine, valine, isoleucine, phenylalanine, tyrosine, serine, threonine, aspartic and anthranilic acid.The structures of the prepared compounds were confirmed by infrared spectra, proton magnetic resonance spectra, Mass spectra and elementary analysis. Surface tension, Kraft point, foaming power, critical micelle concentration emulsion and Ca++ stabilities were determined. Antimicrobial activity and biodegradability were also screened.Se prepararon una serie de tensioactivos anfóteros conteniendo un grupo alfa hidroxi éster y un residuo de aminoácido por adición de derivados epoxy (obtenidos mediante epoxidación de metacrilato de alquilo a diferentes tipos de aminoácidos (glicina, alanina, valina, isoleucina, fenilalanina, tirosina, serina, treonina y ácidos aspártico y antranílico. Las estructuras de los compuestos preparados se confirmaron por los espectros de infrarrojo, de masa, resonancia magnética nuclear de protones y análisis elemental. Se determinaron la tensión superficial, el punto de Kraft, el poder espumante, la concentración micelar crítica en emulsión y las estabilidades de Ca++. También se estudiaron la actividad antimicrobiana y la biodegradabilidad.

  20. Studies on the riboflavin, pantothenic acid, nicotinic acid and choline requirements of young Embden geese

    Science.gov (United States)

    Serafin, J.A.

    1981-01-01

    Four experiments were conducted to examine the riboflavin, pantothenic acid, nicotinic acid, and choline requirements of young Embden geese fed purified diets. Goslings fed diets deficient in either riboflavin, pantothenic acid, nicotinic acid, or choline grew poorly. Feeding a pantothenic acid-deficient diet resulted in 100% mortality. Goslings fed diets containing 530 mg/kg of choline or less developed perosis. Under the conditions of these experiments it was found that: 1) goslings require no more than 3.84 mg/kg of riboflavin and 31.2 mg/kg of nicotinic acid in the diet for rapid growth and normal development, 2) the pantothenic acid requirement of goslings is no more than 12.6 mg/kg of diet, and 3) a dietary choline level of 1530 mg/kg is adequate for both the prevention of perosis and rapid growth of goslings. The levels of vitamins found to support normal growth and development of goslings appear to be similar to requirements of other species that have been examined.

  1. Identification of essential amino acid residues in the nisin dehydratase NisB

    Directory of Open Access Journals (Sweden)

    Rustem eKhusainov

    2015-02-01

    Full Text Available Nisin is a posttranslationally-modified antimicrobial peptide that has the ability to induce its own biosynthesis. Serines and threonines in the modifiable core peptide part of precursor nisin are dehydrated to dehydroalanines and dehydrobutyrines by the dehydratase NisB, and subsequently cysteines are coupled to the dehydroamino acids by the cyclase NisC. In this study, we applied extensive site-directed mutagenesis, together with direct binding studies, to investigate the molecular mechanism of the dehydratase NisB. We use a natural nisin-producing strain as a host to probe mutant-NisB functionality. Importantly, we are able to differentiate between intracellular and secreted fully dehydrated precursor nisin, enabling investigation of the NisB properties needed for the release of dehydrated precursor nisin to its devoted secretion system NisT. We report that single amino acid substitutions of conserved residues, i.e. R83A, R83M and R87A result in incomplete dehydration of precursor nisin and prevention of secretion. Single point NisB mutants Y80F and H961A, result in a complete lack of dehydration of precursor nisin, but do not abrogate precursor nisin binding. The data indicate that residues Y80 and H961 are directly involved in catalysis, fitting well with their position in the recently published 3D-structure of NisB. We confirm, by in vivo studies, results that were previously obtained from in vitro experiments and NisB structure elucidation and show that previous findings translate well to effects seen in the original production host.

  2. Branched chain amino acids requirements and metabolism in pigs

    DEFF Research Database (Denmark)

    Assadi Soumeh, Elham

    2015-01-01

    There is an interest to reduce the dietary crude protein (CP) level to promote the gut health of piglets, eliminate the environmental nitrogen load from intensive pig farming, and to reduce diet costs. This is possible by estimating individual amino acid (AA) requirements and by optimizing the diet...... according to the ideal protein profile that is compatible with the animal AA demand for normal body function. During the past decades, it has been tried to understand and characterize branched chain amino acids (BCAA) requirements, biological importance, and mode of actions. This is interesting for two...... of the last “-omics”, is a global analysis and interpretation of metabolome in specific health or nutritional status. Non-targeted metabolomics is used for screening the metabolic profile, and the metabolic signature could be used for hypothesis generation. The results of a non-targeted LC-MS metabolomics...

  3. Mutation-induced quisqualic acid and ibotenic acid affinity at the metabotropic glutamate receptor subtype 4: ligand selectivity results from a synergy of several amino acid residues

    DEFF Research Database (Denmark)

    Hermit, Mette B; Greenwood, Jeremy R; Bräuner-Osborne, Hans

    2004-01-01

    The metabotropic glutamate receptors (mGluRs) are key modulators of excitatory neurotransmission in the central nervous system. The eight mGluR subtypes are seven trans-membrane-spanning proteins that possess a large extracellular amino-terminal domain in which the endogenous ligand binding pocket...... resides. In this study, we have identified four non-conserved amino acid residues that are essential for differentiating mGluR1 from mGluR4. Our approach has been to increase the affinity of the classic mGluR1 agonists, quisqualic acid and ibotenic acid, at mGluR4 by making various point mutations......, the mutations K74Y and K317R induced dramatic triple-order-of-magnitude increases in the affinity of ibotenic acid at mGluR4, making the affinity equivalent to that of mGluR1. Furthermore, the affinity of quisqualic acid at mGluR4 was increased to the same level as mGluR1 by the two double mutations, K74Y/K317R...

  4. Prediction of beta-turns from amino acid sequences using the residue-coupled model.

    Science.gov (United States)

    Guruprasad, K; Shukla, S

    2003-04-01

    We evaluated the prediction of beta-turns from amino acid sequences using the residue-coupled model with an enlarged representative protein data set selected from the Protein Data Bank. Our results show that the probability values derived from a data set comprising 425 protein chains yielded an overall beta-turn prediction accuracy 68.74%, compared with 94.7% reported earlier on a data set of 30 proteins using the same method. However, we noted that the overall beta-turn prediction accuracy using probability values derived from the 30-protein data set reduces to 40.74% when tested on the data set comprising 425 protein chains. In contrast, using probability values derived from the 425 data set used in this analysis, the overall beta-turn prediction accuracy yielded consistent results when tested on either the 30-protein data set (64.62%) used earlier or a more recent representative data set comprising 619 protein chains (64.66%) or on a jackknife data set comprising 476 representative protein chains (63.38%). We therefore recommend the use of probability values derived from the 425 representative protein chains data set reported here, which gives more realistic and consistent predictions of beta-turns from amino acid sequences.

  5. Enzyme active site mimics based on TriAzaCyclophane (TAC)-scaffolded peptides and amino acid residues

    NARCIS (Netherlands)

    Albada, H.B.

    2009-01-01

    This thesis describes the scope and limitations of the application of TriAzaCyclophane (TAC)-scaffolded peptides or amino acid residues as enzyme active site mimics, as ligands in asymmetric catalysis and as hydrolysis catalysts attached to vancomycin. For the mimicry of functional group enzymes, of

  6. Queen survival and oxalic acid residues in sugar stores after summer application against Varroa destructor in honey bees (Apis mellifera)

    NARCIS (Netherlands)

    Cornelissen, B.; Donders, J.N.L.C.; Stratum, van P.; Blacquière, T.; Dooremalen, van C.

    2012-01-01

    Methods using oxalic acid (OA) to control Varroa destructor in honey bee (Apis mellifera) colonies are widely applied. In this study, the effects of an OA spray application in early summer on the survival of young and old queens, and on OA residues in sugar stores were investigated. A questionnaire

  7. Synthesis of two hyaluronic-acid-related oligosaccharide 4-methoxyphenyl glycosides having a beta-D-glucuronic acid residue at the reducing end

    NARCIS (Netherlands)

    Halkes, K.M.; Slaghek, T.M.; Hypponen, T.K.; Kamerling, J.P.; Vliegenthart, J.F.G.

    1999-01-01

    Synthesis of two hyaluronic-acid-related oligosaccharides, the 4-methoxyphenyl β-glycosides of β-D-GlcpA-(1→3)-β-D-GlcpNAc-(1→4)-D-GlcpA and β-D-GlcpA-(1→3)-β-D-GlcpNAc-(1→4)-β-D-GlcpA-(1→3)- β-D-GJcpNAc-(1→4)-D-GlcpA, is described. D-Glucopyranosyluronic acid residues were obtained by selective

  8. Synthesis of two hyaluronic-acid-related oligosaccharide 4-methoxyphenyl glycosides having a β-D-glucuronic acid residue at the reducing end

    NARCIS (Netherlands)

    Vliegenthart, J.F.G.; Halkes, K.M.; Slaghek, T.M.; Hyppönen, T.K.; Kamerling, J.P.

    1999-01-01

    Synthesis of two hyaluronic-acid-related oligosaccharides, the 4-methoxyphenyl beta-glycosides of beta-D-GlcpA-(1->3)-beta-D-GlcpNAc-(1->4)-D-GlcpA and beta-D-GlcpA-(1->3)-beta-D-GlcpNAc-(1->4)-beta-D-GlcpA-(1->3)-beta-D-GlcpNAc-(1->4)-D-GlcpA, is described. D-Glucopyranosyluronic acid residues were

  9. Catalytically important amino-acid residues of abalone alginate lyase HdAly assessed by site-directed mutagenesis

    OpenAIRE

    Yamamoto, Sayo; Sahara, Takehiko; Sato, Daisuke; Kawasaki, Kosei; Ohgiya, Satoru; Inoue, Akira; Ojima, Takao

    2008-01-01

    Alginate lyase is an enzyme that degrades alginate chains via β-elimination and has been used for the production of alginate oligosaccharides and protoplasts from brown algae. Previously, we deduced the amino-acid sequence of an abalone alginate lyase, HdAly, from its cDNA sequence and, through multiple amino-acid sequence alignment, found that several basic amino-acid residues were highly conserved among the polysaccharide-lyase family 14 (PL-14) enzymes including HdAly. In the present study...

  10. SucStruct: Prediction of succinylated lysine residues by using structural properties of amino acids.

    Science.gov (United States)

    López, Yosvany; Dehzangi, Abdollah; Lal, Sunil Pranit; Taherzadeh, Ghazaleh; Michaelson, Jacob; Sattar, Abdul; Tsunoda, Tatsuhiko; Sharma, Alok

    2017-06-15

    Post-Translational Modification (PTM) is a biological reaction which contributes to diversify the proteome. Despite many modifications with important roles in 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. In contrast to 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 treatment for dealing with class imbalance and designed a pruned decision tree for classification. Our predictor, referred to 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. Copyright © 2017 Elsevier Inc. All rights reserved.

  11. Superabsorbent materials from grafting of acrylic acid onto Thai agricultural residues by gamma irradiation

    International Nuclear Information System (INIS)

    Wongsawaeng, Doonyapong; Jumpee, Chayanit

    2016-01-01

    Superabsorbent polymers based on ubiquitous agricultural residues: sugarcane, water hyacinth, rice straw, coconut shell and palm fruit bunch substrates, were successfully synthesized. Gamma radiation from Co-60 was employed to graft acrylic acid (AA) onto the substrates. Rice straw exhibited the highest equilibrium swelling ratio of 78.90 g/g at 6 kGy of absorbed gamma ray dose and 14%v/v AA concentration. The rate of water absorption was rapid at the beginning and became reduced with increasing immersion time. After about 3.5 hours, the absorption reached approximately 90% of the saturation value. Temperature plays a critical role on the rate of water evaporation from the superabsorbent. As for the one experiencing 35degC-40degC temperature, the weight of the saturated superabsorbent reduced to approximately 50% of the original value in 13 hours. However, for the one experiencing room temperature (24.2degC-27.7degC), approximately 58 hours were needed to reduce the weight by half. The superabsorbent polymer was able to absorb about 203% of the polymer's dry weight and did not release urea when eluded by water. Moreover, the polymer was able to hold water very well for at least 3 weeks and did not degrade until at least 6 weeks, ensuring biodegradability. (author)

  12. A single amino acid residue controls Ca2+ signaling by an octopamine receptor from Drosophila melanogaster.

    Science.gov (United States)

    Hoff, Max; Balfanz, Sabine; Ehling, Petra; Gensch, Thomas; Baumann, Arnd

    2011-07-01

    Rhythmic activity of cells and cellular networks plays an important role in physiology. In the nervous system oscillations of electrical activity and/or second messenger concentrations are important to synchronize neuronal activity. At the molecular level, rhythmic activity can be initiated by different routes. We have recently shown that an octopamine-activated G-protein-coupled receptor (GPCR; DmOctα1Rb, CG3856) from Drosophila initiates Ca(2+) oscillations. Here, we have unraveled the molecular basis of cellular Ca(2+) signaling controlled by the DmOctα1Rb receptor using a combination of pharmacological intervention, site-directed mutagenesis, and functional cellular Ca(2+) imaging on heterologously expressed receptors. Phosphorylation of a single amino acid residue in the third intracellular loop of the GPCR by PKC is necessary and sufficient to desensitize the receptor. From its desensitized state, DmOctα1Rb is resensitized by dephosphorylation, and a new Ca(2+) signal occurs on octopamine stimulation. Our findings show that transient changes of the receptor's surface profile have a strong effect on its physiological signaling properties. We expect that the detailed knowledge of DmOctα1Rb-dependent signal transduction fosters the identification of specific drugs that can be used for GPCR-mediated pest control, since octopamine serves important physiological and behavioral functions in arthropods.

  13. Amino acid residues involved in membrane insertion and pore formation of Clostridium botulinum C2 toxin.

    Science.gov (United States)

    Lang, Alexander E; Neumeyer, Tobias; Sun, Jianjun; Collier, R John; Benz, Roland; Aktories, Klaus

    2008-08-12

    The actin-ADP-ribosylating Clostridium botulinum C2 toxin consists of the enzymatic component C2I and the binding component C2II. C2II forms heptameric channels involved in translocation of the enzymatic component into the target cell. On the basis of the heptameric toxin channel, we studied functional consequences of mutagenesis of amino acid residues probably lining the lumen of the toxin channel. Substitution of glutamate-399 of C2II with alanine blocked channel formation and cytotoxicity of the holotoxin. Although cytotoxicity and rounding up of cells by C2I were completely blocked by exchange of phenylalanine-428 with alanine, the mutation increased potassium conductance caused by C2II in artificial membranes by about 2-3-fold over that of wild-type toxin. In contrast to its effects on single-channel potassium conductance in artificial membranes, the F428A mutation delayed the kinetics of pore formation in lipid vesicles and inhibited the activity of C2II in promoting (86)Rb (+) release from preloaded intact cells after pH shift of the medium. Moreover, F428A C2II exhibited delayed and diminished formation of C2II aggregates at low pH, indicating major changes of the biophysical properties of the toxin. The data indicate that phenylalanine-428 of C2II plays a major role in conformational changes occurring during pore formation of the binding component of C2II.

  14. Protonation of key acidic residues is critical for the K⁺-selectivity of the Na/K pump.

    Science.gov (United States)

    Yu, Haibo; Ratheal, Ian M; Artigas, Pablo; Roux, Benoît

    2011-09-11

    The sodium-potassium (Na/K) pump is a P-type ATPase that generates Na(+) and K(+) concentration gradients across the cell membrane. For each hydrolyzed ATP molecule, the pump extrudes three Na(+) and imports two K(+) by alternating between outward- and inward-facing conformations that preferentially bind K(+) or Na(+), respectively. Remarkably, the selective K(+) and Na(+) binding sites share several residues, and how the pump is able to achieve the selectivity required for the functional cycle is unclear. Here, free energy-perturbation molecular dynamics (FEP/MD) simulations based on the crystal structures of the Na/K pump in a K(+)-loaded state (E2·P(i)) reveal that protonation of the high-field acidic side chains involved in the binding sites is crucial to achieving the proper K(+) selectivity. This prediction is tested with electrophysiological experiments showing that the selectivity of the E2P state for K(+) over Na(+) is affected by extracellular pH.

  15. Interaction of acid mine drainage with Ordinary Portland Cement blended solid residues generated from active treatment of acid mine drainage with coal fly ash.

    Science.gov (United States)

    Gitari, Wilson M; Petrik, Leslie F; Key, David L; Okujeni, Charles

    2011-01-01

    Fly ash (FA) has been investigated as a possible treatment agent for Acid mine drainage (AMD) and established to be an alternative, cheap and economically viable agent compared to the conventional alkaline agents. However, this treatment option also leads to generation of solid residues (SR) that require disposal and one of the proposed disposal method is a backfill in coal mine voids. In this study, the interaction of the SR with AMD that is likely to be present in such backfill scenario was simulated by draining columns packed with SR and SR + 6% Ordinary Portland Cement (OPC) unsaturated with simulated AMD over a 6 month period. The evolving geochemistry of the liquid/solid (L/S) system was evaluated in-terms of the mineral phases likely or controlling contaminants attenuation at the different pH regimes generated. Stepwise acidification of the percolates was observed as the drainage progressed. Two pH buffer zones were observed (7.5-9 and 3-4) for SR and (11.2-11.3 and 3.5-4) for SR + 6% OPC. The solid residue cores (SR) appeared to have a significant buffering capacity, maintaining a neutral to slightly alkaline pH in the leachates for an extended period of time (97 days: L/S 4.3) while SR + 6% OPC reduced this neutralization capacity to 22 days (L/S 1.9). Interaction of AMD with SR or SR + 6% OPC generated alkaline conditions that favored precipitation of Fe, Al, Mn-(oxy) hydroxides, Fe and Ca-Al hydroxysulphates that greatly contributed to the contaminants removal. However, precipitation of these phases was restricted to the pH of the leachates remaining at neutral to circum-neutral levels. Backfill of mine voids with SR promises to be a feasible technology for the disposal of the SR but its success will greatly depend on the disposal scenario, AMD generated and the alkalinity generating potential of the SR. A disadvantage would be the possible re-dissolution of the precipitated phases at pH water column. However extrapolation of this concept to a field

  16. A 13C{31P} REDOR NMR Investigation of the Role of Glutamic Acid Residues in Statherin-Hydroxyapatite Recognition

    Science.gov (United States)

    Ndao, Moise; Ash, Jason T.; Breen, Nicholas F.; Goobes, Gil; Stayton, Patrick S.; Drobny, Gary P.

    2011-01-01

    The side chain carboxyl groups of acidic proteins found in the extra-cellular matrix (ECM) of mineralized tissues play a key role in promoting or inhibiting the growth of minerals such as hydroxyapatite (HAP), the principal mineral component of bone and teeth. Among the acidic proteins found in the saliva is statherin, a 43-residue tyrosine-rich peptide that is a potent lubricant in the salivary pellicle and an inhibitor of both HAP crystal nucleation and growth. Three acidic amino acids – D1, E4, and E5 – are located in the N-terminal 15 amino acid segment, with a fourth amino acid, E26, located outside the N-terminus. We have utilized 13C{31P} REDOR NMR to analyze the role played by acidic amino acids in the binding mechanism of statherin to the HAP surface by measuring the distance between the δ-carboxyl 13C spins of the three glutamic acid side chains of statherin (residues E4, E5, E26) and 31P spins of the phosphate groups at the HAP surface. 13C{31P} REDOR studies of glutamic-5-13C acid incorporated at positions E4 and E26 indicate a 13C–31P distance of more than 6.5 Å between the side chain carboxyl 13C spin of E4 and the closest 31P in the HAP surface. In contrast, the carboxyl 13C spin at E5 has a much shorter 13C–31P internuclear distance of 4.25±0.09 Å, indicating that the carboxyl group of this side chain interacts directly with the surface. 13C T1ρ and slow-spinning MAS studies indicate that the motions of the side chains of E4 and E5 are more restricted than that of E26. Together, these results provide further insight into the molecular interactions of statherin with HAP surfaces. PMID:19678690

  17. Reuse of acid coagulant-recovered drinking waterworks sludge residual to remove phosphorus from wastewater

    Science.gov (United States)

    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.

  18. 40 CFR 180.1090 - Lactic acid; exemption from the requirement of a tolerance.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 23 2010-07-01 2010-07-01 false Lactic acid; exemption from the... Exemptions From Tolerances § 180.1090 Lactic acid; exemption from the requirement of a tolerance. Lactic acid (2-hydroxypropanoic acid) is exempted from the requirement of a tolerance when used as a plant growth...

  19. Treatment of air pollution control residues with iron rich waste sulfuric acid: does it work for antimony (Sb)?

    Science.gov (United States)

    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. Copyright © 2013 Elsevier B.V. All rights reserved.

  20. A highly Conserved Aspartic Acid Residue of the Chitosanase from Bacillus Sp. TS Is Involved in the Substrate Binding.

    Science.gov (United States)

    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.

  1. The periplasmic transaminase PtaA of Pseudomonas fluorescens converts the glutamic acid residue at the pyoverdine fluorophore to α-ketoglutaric acid.

    Science.gov (United States)

    Ringel, Michael T; Dräger, Gerald; Brüser, Thomas

    2017-11-10

    The periplasmic conversion of ferribactin to pyoverdine is essential for siderophore biogenesis in fluorescent pseudomonads, such as pathogenic Pseudomonas aeruginosa or plant growth-promoting Pseudomonas fluorescens The non-ribosomal peptide ferribactin undergoes cyclizations and oxidations that result in the fluorophore, and a strictly conserved fluorophore-bound glutamic acid residue is converted to a range of variants, including succinamide, succinic acid, and α-ketoglutaric acid residues. We recently discovered that the pyridoxal phosphate-containing enzyme PvdN is responsible for the generation of the succinamide, which can be hydrolyzed to succinic acid. Based on this, a distinct unknown enzyme was postulated to be responsible for the conversion of the glutamic acid to α-ketoglutaric acid. Here we report the identification and characterization of this enzyme in P. fluorescens strain A506. In silico analyses indicated a periplasmic transaminase in fluorescent pseudomonads and other proteobacteria that we termed PtaA for " p eriplasmic t ransaminase A " An in-frame-deleted ptaA mutant selectively lacked the α-ketoglutaric acid form of pyoverdine, and recombinant PtaA complemented this phenotype. The ptaA / pvdN double mutant produced exclusively the glutamic acid form of pyoverdine. PtaA is homodimeric and contains a pyridoxal phosphate cofactor. Mutation of the active-site lysine abolished PtaA activity and affected folding as well as Tat-dependent transport of the enzyme. In pseudomonads, the occurrence of ptaA correlates with the occurrence of α-ketoglutaric acid forms of pyoverdines. As this enzyme is not restricted to pyoverdine-producing bacteria, its catalysis of periplasmic transaminations is most likely a general tool for specific biosynthetic pathways. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

  2. Retinoic acid activates two pathways required for meiosis in mice.

    Directory of Open Access Journals (Sweden)

    Jana Koubova

    2014-08-01

    Full Text Available In all sexually reproducing organisms, cells of the germ line must transition from mitosis to meiosis. In mice, retinoic acid (RA, the extrinsic signal for meiotic initiation, activates transcription of Stra8, which is required for meiotic DNA replication and the subsequent processes of meiotic prophase. Here we report that RA also activates transcription of Rec8, which encodes a component of the cohesin complex that accumulates during meiotic S phase, and which is essential for chromosome synapsis and segregation. This RA induction of Rec8 occurs in parallel with the induction of Stra8, and independently of Stra8 function, and it is conserved between the sexes. Further, RA induction of Rec8, like that of Stra8, requires the germ-cell-intrinsic competence factor Dazl. Our findings strengthen the importance of RA and Dazl in the meiotic transition, provide important details about the Stra8 pathway, and open avenues to investigate early meiosis through analysis of Rec8 induction and function.

  3. Citric-acid preacidification enhanced electrokinetic remediation for removal of chromium from chromium-residue-contaminated soil.

    Science.gov (United States)

    Meng, Fansheng; Xue, Hao; Wang, Yeyao; Zheng, Binghui; Wang, Juling

    2018-02-01

    Electrokinetic experiments were conducted on chromium-residue-contaminated soils collected from a chemical plant in China. Acidification-electrokinetic remediation technology was proposed in order to solve the problem of removing inefficient with ordinary electrokinetic. The results showed that electrokinetic remediation removal efficiency of chromium from chromium-contaminated soil was significantly enhanced with acidizing pretreatment. The total chromium [Cr(T)] and hexavalent chromium [Cr(VI)] removal rate of the group acidized by citric acid (0.9 mol/L) for 5 days was increased from 6.23% and 19.01% in the acid-free experiments to 26.97% and 77.66% in the acidification-treated experiments, respectively. In addition, part of chromium with the state of carbonate-combined will be converted into water-soluble state through acidification to improve the removal efficiency. Within the appropriate concentration range, the higher concentration of acid was, the more chromium was released. So the removal efficiency of chromium depended on the acid concentration. The citric acid is also a kind of complexing agent, which produced complexation with Cr that was released by the electrokinetic treatment and then enhanced the removal efficiency. The major speciation of chromium that was removed from soils by acidification-electrokinetics remediation was acid-soluble speciation, revivification speciation and oxidation speciation, which reduced biological availability of chromium.

  4. Structural and functional characterization of Rpn12 identifies residues required for Rpn10 proteasome incorporation.

    Science.gov (United States)

    Boehringer, Jonas; Riedinger, Christiane; Paraskevopoulos, Konstantinos; Johnson, Eachan O D; Lowe, Edward D; Khoudian, Christina; Smith, Dominique; Noble, Martin E M; Gordon, Colin; Endicott, Jane A

    2012-11-15

    The ubiquitin-proteasome system targets selected proteins for degradation by the 26S proteasome. Rpn12 is an essential component of the 19S regulatory particle and plays a role in recruiting the extrinsic ubiquitin receptor Rpn10. In the present paper we report the crystal structure of Rpn12, a proteasomal PCI-domain-containing protein. The structure helps to define a core structural motif for the PCI domain and identifies potential sites through which Rpn12 might form protein-protein interactions. We demonstrate that mutating residues at one of these sites impairs Rpn12 binding to Rpn10 in vitro and reduces Rpn10 incorporation into proteasomes in vivo.

  5. Evaluation of methods to estimate the essential amino acids requirements of fish from the muscle amino acid profile

    Directory of Open Access Journals (Sweden)

    Álvaro José de Almeida Bicudo

    2014-03-01

    Full Text Available Many methods to estimate amino acid requirement based on amino acid profile of fish have been proposed. This study evaluates the methodology proposed by Meyer & Fracalossi (2005 and by Tacon (1989 to estimate amino acids requirement of fish, which do exempt knowledge on previous nutritional requirement of reference amino acid. Data on amino acid requirement of pacu, Piaractus mesopotamicus, were used to validate de accuracy of those methods. Meyer & Fracalossi's and Tacon's methodology estimated the lysine requirement of pacu, respectively, at 13 and 23% above requirement determined using dose-response method. The values estimated by both methods lie within the range of requirements determined for other omnivorous fish species, the Meyer & Fracalossi (2005 method showing better accuracy.

  6. PAMP-induced defense responses in potato require both salicylic acid and jasmonic acid.

    Science.gov (United States)

    Halim, Vincentius A; Altmann, Simone; Ellinger, Dorothea; Eschen-Lippold, Lennart; Miersch, Otto; Scheel, Dierk; Rosahl, Sabine

    2009-01-01

    To elucidate the molecular mechanisms underlying pathogen-associated molecular pattern (PAMP)-induced defense responses in potato (Solanum tuberosum), the role of the signaling compounds salicylic acid (SA) and jasmonic acid (JA) was analyzed. Pep-13, a PAMP from Phytophthora, induces the accumulation of SA, JA and hydrogen peroxide, as well as the activation of defense genes and hypersensitive-like cell death. We have previously shown that SA is required for Pep-13-induced defense responses. To assess the importance of JA, RNA interference constructs targeted at the JA biosynthetic genes, allene oxide cyclase and 12-oxophytodienoic acid reductase, were expressed in transgenic potato plants. In addition, expression of the F-box protein COI1 was reduced by RNA interference. Plants expressing the RNA interference constructs failed to accumulate the respective transcripts in response to wounding or Pep-13 treatment, neither did they contain significant amounts of JA after elicitation. In response to infiltration of Pep-13, the transgenic plants exhibited a highly reduced accumulation of reactive oxygen species as well as reduced hypersensitive cell death. The ability of the JA-deficient plants to accumulate SA suggests that SA accumulation is independent or upstream of JA accumulation. These data show that PAMP responses in potato require both SA and JA and that, in contrast to Arabidopsis, these compounds act in the same signal transduction pathway. Despite their inability to fully respond to PAMP treatment, the transgenic RNA interference plants are not altered in their basal defense against Phytophthora infestans.

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

    Energy Technology Data Exchange (ETDEWEB)

    Shiheido, Hirokazu, E-mail: shiheido@ak.med.kyoto-u.ac.jp; 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.

  8. CHOICE FEEDING AND AMINO ACID REQUIREMENTS FOR BROILERS

    Directory of Open Access Journals (Sweden)

    B. Indarsih

    2011-12-01

    Full Text Available The study was conducted as a completely randomized design, with a factorial arrangement to determine the response of commercial broilers to choice feeding and limiting amino acids on growth and carcass performance. A total of 432 male birds were weighed at one-d-old and randomly distributed to 48 wire-floored brooder cage each 1.0 m2. There were 2 sexes and 4 dietary treatments with 6 replicates each of 9 birds. Birds were given one of three dietary regimens with dietary change every 7 days. All groups were fed free choice of summit and dilution diets. The estimated dietary level of crude protein at day-old was 240 g/kg and the level at 42 d was either 120, 150 or 180 g/kg for females or 130, 160 and 190 g/kg for males. At 43 d of age, all birds from each dietary treatment were slaughtered for measurement of body composition. Results reveal that lysine requirement for maximum gain in this study was higher than NRC recommendation. The free choice-fed bird was significantly higher, in terms of growth and body composition than that obtained on the low dietary protein regimen.Keyword

  9. Multiple roles of the extracellular vestibule amino acid residues in the function of the rat P2X4 receptor.

    Directory of Open Access Journals (Sweden)

    Milos B Rokic

    Full Text Available The binding of ATP to trimeric P2X receptors (P2XR causes an enlargement of the receptor extracellular vestibule, leading to opening of the cation-selective transmembrane pore, but specific roles of vestibule amino acid residues in receptor activation have not been evaluated systematically. In this study, alanine or cysteine scanning mutagenesis of V47-V61 and F324-N338 sequences of rat P2X4R revealed that V49, Y54, Q55, F324, and G325 mutants were poorly responsive to ATP and trafficking was only affected by the V49 mutation. The Y54F and Y54W mutations, but not the Y54L mutation, rescued receptor function, suggesting that an aromatic residue is important at this position. Furthermore, the Y54A and Y54C receptor function was partially rescued by ivermectin, a positive allosteric modulator of P2X4R, suggesting a rightward shift in the potency of ATP to activate P2X4R. The Q55T, Q55N, Q55E, and Q55K mutations resulted in non-responsive receptors and only the Q55E mutant was ivermectin-sensitive. The F324L, F324Y, and F324W mutations also rescued receptor function partially or completely, ivermectin action on channel gating was preserved in all mutants, and changes in ATP responsiveness correlated with the hydrophobicity and side chain volume of the substituent. The G325P mutant had a normal response to ATP, suggesting that G325 is a flexible hinge. A topological analysis revealed that the G325 and F324 residues disrupt a β-sheet upon ATP binding. These results indicate multiple roles of the extracellular vestibule amino acid residues in the P2X4R function: the V49 residue is important for receptor trafficking to plasma membrane, the Y54 and Q55 residues play a critical role in channel gating and the F324 and G325 residues are critical for vestibule widening.

  10. Residue-specific incorporation of noncanonical amino acids for protein engineering

    NARCIS (Netherlands)

    van Eldijk, Mark B.; van Hest, Jan C.M.; Lemke, E.A.

    2018-01-01

    The incorporation of noncanonical amino acids has given protein chemists access to an expanded repertoire of amino acids. This methodology has significantly broadened the scope of protein engineering allowing introduction of amino acids with non-native functionalities, such as bioorthogonal reactive

  11. Two Arginine Residues of Streptococcus gordonii Sialic Acid-Binding Adhesin Hsa Are Essential for Interaction to Host Cell Receptors.

    Directory of Open Access Journals (Sweden)

    Yumiko Urano-Tashiro

    Full Text Available Hsa is a large, serine-rich protein of Streptococcus gordonii DL1 that mediates binding to α2-3-linked sialic acid termini of glycoproteins, including platelet glycoprotein Ibα, and erythrocyte membrane protein glycophorin A, and band 3. The binding of Hsa to platelet glycoprotein Ibα contributes to the pathogenesis of infective endocarditis. This interaction appears to be mediated by a second non-repetitive region (NR2 of Hsa. However, the molecular details of the interaction between the Hsa NR2 region and these glycoproteins are not well understood. In the present study, we identified the amino acid residues of the Hsa NR2 region that are involved in sialic acid recognition. To identify the sialic acid-binding site of Hsa NR2 region, we prepared various mutants of Hsa NR2 fused with glutathione transferase. Fusion proteins harboring Arg340 to Asn (R340N or Arg365 to Asn (R365N substitutions in the NR2 domain exhibited significantly reduced binding to human erythrocytes and platelets. A sugar-binding assay showed that these mutant proteins abolished binding to α2-3-linked sialic acid. Furthermore, we established S. gordonii DL1 derivatives that encoded the corresponding Hsa mutant protein. In whole-cell assays, these mutant strains showed significant reductions in hemagglutination, in platelet aggregation, and in adhesion to human leukocytes. These results indicate that the Arg340 and Arg365 residues of Hsa play an important role in the binding of Hsa to α2-3-linked sialic acid-containing glycoproteins.

  12. Asthma induction in mice leads to appearance of alpha2-3- and alpha2-6-linked sialic acid residues in respiratory goblet-like cells

    DEFF Research Database (Denmark)

    Kirkeby, Svend; Jensen, Niels-Erik Viby; Mandel, Ulla

    2008-01-01

    Allergic asthmatic inflammation in mice was induced by sensitization with ovalbumin and lipopolysaccharide from Escherichia coli and visualized in the airways of asthmatic mice by spatial and temporal changes of carbohydrates containing sialic acid residues. Immunohistochemistry was used...

  13. Importance of Terminal Amino Acid Residues to the Transport of Oligopeptides across the Caco-2 Cell Monolayer.

    Science.gov (United States)

    Ding, Long; Wang, Liying; Yu, Zhipeng; Ma, Sitong; Du, Zhiyang; Zhang, Ting; Liu, Jingbo

    2017-09-06

    The objective of this paper was to investigate the effects of terminal amino acids on the transport of oligopeptides across the Caco-2 cell monolayer. Ala-based tetra- and pentapeptides were designed, and the N- or C-terminal amino acid residues were replaced by different amino acids. The results showed that the oligopeptides had a wide range of transport permeability across the Caco-2 cell monolayer and could be divided into four categories: non-/poor permeability, low permeability, intermediate permeability, and good permeability. Tetrapeptides with N-terminal Leu, Pro, Ile, Cys, Met, and Val or C-terminal Val showed the highest permeability, with apparent permeability coefficient (P app ) values over 10 × 10 -6 cm/s (p transport of tetrapeptides. Pentapeptides with N- or C-terminal Tyr also showed high permeability levels, with P app values of about 10 × 10 -6 cm/s. The amino acids Glu, Asn, and Thr at the N terminus or Lys, Asp, and Arg at the C terminus were also beneficial for the transport of tetra- and pentapeptides, with P app values ranging from 1 × 10 -6 to 10 × 10 -6 cm/s. In addition, peptides with amino acids replaced at the N terminus generally showed higher permeability than those with amino acids replaced at the C terminus (p transport of oligopeptides across the Caco-2 cell monolayer.

  14. Amino acid residues important for substrate specificity of the amino acid permeases Can I p and Gnp I p in Saccharomyces cerevisiae

    DEFF Research Database (Denmark)

    Regenberg, Birgitte; Kielland-Brandt, M.C.

    2001-01-01

    Deletion of the general amino acid permease gene GAP1 abolishes uptake of L-citrulline in Saccharomyces cerevisiae, resulting in the inability to grow on L-citrulline as sole nitrogen source. Selection for suppressor mutants that restored growth on L-citrulline led to isolation of 21 mutations...... in the arginine permease gene CAN1. One similar mutation was found in the glutamine-asparagine permease gene GNP1. L-[C-14]citrulline uptake measurements confirmed that suppressor mutations in CAN1 conferred uptake of this amino acid, while none of the mutant permeases had lost the ability to transport L-[C-14......]arginine. Substrate specificity seemed to remain narrow in most cases, and broad substrate specificity was only observed in the cases where mutations affect two proline residues (P148 and P313) that are both conserved in the amino acid-polyamine-choline (APC) transporter superfamily. We found mutations...

  15. Identification of functionally important amino acid residues in the mitochondria targeting sequence of Hepatitis B virus X protein

    International Nuclear Information System (INIS)

    Li, Sai Kam; Ho, Sai Fan; Tsui, Kwok Wing; Fung, Kwok Pui; Waye, M.Y. Mary

    2008-01-01

    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

  16. 40 CFR 180.1187 - L-glutamic acid; exemption from the requirement of a tolerance.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 23 2010-07-01 2010-07-01 false L-glutamic acid; exemption from the... Exemptions From Tolerances § 180.1187 L-glutamic acid; exemption from the requirement of a tolerance. L-glutamic acid is exempt from the requirement of a tolerance on all food commodities when used in accordance...

  17. 46 CFR 153.557 - Special requirements for hydrochloric acid.

    Science.gov (United States)

    2010-10-01

    ... CARGOES SHIPS CARRYING BULK LIQUID, LIQUEFIED GAS, OR COMPRESSED GAS HAZARDOUS MATERIALS Design and... system that carries hydrochloric acid must be lined with: (1) Natural rubber; (2) Neoprene; or (3) A material approved for hydrochloric acid tanks by the Commandant (CG-522). (b) Containment systems for...

  18. Evidence for a Proton Transfer Network and a Required Persulfide-Bond-Forming Cysteine Residue in Ni-Containing Carbon Monoxide Dehydrogenases

    International Nuclear Information System (INIS)

    Eun Jin Kim; Jian Feng; Bramlett, Matthew R.; Lindahl, Paul A.

    2004-01-01

    OAK-B135 Carbon monoxide dehydrogenase from Moorella thermoacetica catalyzes the reversible oxidation of CO to CO2 at a nickel-iron-sulfur active-site called the C-cluster. Mutants of a proposed proton transfer pathway and of a cysteine residue recently found to form a persulfide bond with the C-cluster were characterized. Four semi-conserved histidine residues were individually mutated to alanine. His116 and His122 were essential to catalysis, while His113 and His119 attenuated catalysis but were not essential. Significant activity was ''rescued'' by a double mutant where His116 was replaced by Ala and His was also introduced at position 115. Activity was also rescued in double mutants where His122 was replaced by Ala and His was simultaneously introduced at either position 121 or 123. Activity was also ''rescued'' by replacing His with Cys at position 116. Mutation of conserved Lys587 near the C-cluster attenuated activity but did not eliminate it. Activity was virtually abolished in a double mutant where Lys587 and His113 were both changed to Ala. Mutations of conserved Asn284 also attenuated activity. These effects suggest the presence of a network of amino acid residues responsible for proton transfer rather than a single linear pathway. The Ser mutant of the persulfide-forming Cys316 was essentially inactive and displayed no EPR signals originating from the C-cluster. Electronic absorption and metal analysis suggests that the C-cluster is absent in this mutant. The persulfide bond appears to be essential for either the assembly or stability of the C-cluster, and/or for eliciting the redox chemistry of the C-cluster required for catalytic activity

  19. P-aminobenzoic acid and tritiated cyanoborohydride for the detection of pyruvoyl residues in proteins

    International Nuclear Information System (INIS)

    van Poelje, P.D.; Snell, E.E.

    1987-01-01

    A procedure for the detection of covalently bound pyruvic acid in purified proteins or in crude extracts is described. The dialyzed sample is first treated with sodium cyanoborohydride to reduce any Schiff bases present and then incubated with p-aminobenzoic acid and sodium [ 3 H]cyanoborohydride. Derivatized proteins are visualized by fluorography following sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Gel slices containing the labeled proteins are hydrolyzed, and, after removal of polyacrylic acid, the hydrolysate is subjected to ion-exchange high-performance liquid chromatography. The presence of pyruvic acid is established by the detection of a tritiated, 280-nm absorbing compound with a retention time corresponding to that of synthetic N-(p-carboxyphenyl)alanine. The procedure is capable of detecting protein-bound pyruvic acid in the picomolar range and is easily modified to screen for other covalently bound keto acids

  20. Amino-terminal residues of ΔNp63, mutated in ectodermal dysplasia, are required for its transcriptional activity.

    Science.gov (United States)

    Lena, Anna Maria; Duca, Sara; Novelli, Flavia; Melino, Sonia; Annicchiarico-Petruzzelli, Margherita; Melino, Gerry; Candi, Eleonora

    2015-11-13

    p63, a member of the p53 family, is a crucial transcription factor for epithelial development and skin homeostasis. Heterozygous mutations in TP63 gene have been associated with human ectodermal dysplasia disorders. Most of these TP63 mutations are missense mutations causing amino acidic substitutions at p63 DNA binding or SAM domains that reduce or abolish the transcriptional activity of mutants p63. A significant number of mutants, however, resides in part of the p63 protein that apparently do not affect DNA binding and/or transcriptional activity, such as the N-terminal domain. Here, we characterize five p63 mutations at the 5' end of TP63 gene aiming to understand the pathogenesis of the diseases and to uncover the role of ΔNp63α N-terminus residues in determining its transactivation potential. Copyright © 2015 Elsevier Inc. All rights reserved.

  1. Effects of the substitution of amino acid residues, through chemical synthesis, on the conformation and activity of antimicrobial peptides

    Directory of Open Access Journals (Sweden)

    Regina C. Adão

    2012-06-01

    Full Text Available Antimicrobial peptides make up an assorted group of molecules which contain from 12 to 50 amino acid residues and which may be produced by microorganisms, plants and animals. From the discovery that these biomolecules are lethal to bacteria, inhibiting the pathogenic organism’s growth, and are also related to innate and adapted defense mechanisms, the investigation of such molecules came to be an emergent research field, in which more than 1800 antimicrobial peptides have so far been discovered throughout the last three decades. These molecules are potential representatives of a new generation of antibiotic agents and the main motivation for such use is their activity against a wide variety of pathogens, including Gram-positive and Gram-negative bacteria as well as fungi and viruses. An important class of comprising some of these peptides may be found in anurans, from which it has been isolated, a considerable number of antimicrobial peptides with diverse sequences and structures, including linear and dimeric ones. In this work monomeric chains (CH1 e CH2 of the heterodimeric antimicrobial peptide distinctin (isolated in 1999 from Phyllomedusa distincta anurans, as well as its mutated monomers (CH1-S and CH2-S and the heterodimer itself were synthesized. The distinctin is the peptide with two chains of different sequences (Table 1 bound each other by disulfide bond from the cystein residues constituting the heterodimer. To investigate the effects on the biological activity by amino acids substitution at normal distinctin CH1 and CH2 chains, both were synthesized as well as their similar chains (CH1-S and CH2-S in which the cystein (Fig.1 a residues of each chain were changed by serin residues (Fig. 1 b. The new chains were named mutants. The synthesis was carried out in solid phase, using Fmoc strategy. The heterodimer distinctin was obtained from CH1 and CH2 chains coupling through cystein residues air oxidation. The results from HPLC

  2. 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.

    Science.gov (United States)

    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. Copyright © 2014 Elsevier Ltd. All rights reserved.

  3. 40 CFR 158.2082 - Experimental use permit biochemical pesticides residue data requirements table.

    Science.gov (United States)

    2010-07-01

    .... These data requirements apply to all biochemical pesticides, i.e., naturally occurring insect repellents and attractants, semiochemicals (e.g., insect pheromones), natural and plant growth regulators. Notes... food crop use, terrestrial feed crop use, aquatic food crop use, greenhouse food crop use, and indoor...

  4. 78 FR 20029 - Castor Oil, Polymer With Adipic Acid, Linoleic Acid, Oleic Acid and Ricinoleic Acid; Tolerance...

    Science.gov (United States)

    2013-04-03

    ..., Polymer With Adipic Acid, Linoleic Acid, Oleic Acid and Ricinoleic Acid; Tolerance Exemption AGENCY... from the requirement of a tolerance for residues of castor oil, polymer with adipic acid, linoleic acid... pesticide formulation. Advance Polymer Technology submitted a petition to EPA under the Federal Food, Drug...

  5. Carbobenzoxy amino acids: Structural requirements for cholecystokinin receptor antagonist activity

    International Nuclear Information System (INIS)

    Maton, P.N.; Sutliff, V.E.; Jensen, R.T.; Gardner, J.D.

    1985-01-01

    The authors used dispersed acini prepared from guinea pig pancreas to examine 28 carbobenzoxy (CBZ) amino acids for their abilities to function as cholecystokinin receptor antagonists. All amino acid derivatives tested, except for CBZ-alanine, CBZ-glycine, and N alpha-CBZ- lysine, were able to inhibit the stimulation of amylase secretion caused by the C-terminal octapeptide of cholecystokinin. In general, there was a good correlation between the ability of a carbobenzoxy amino acid to inhibit stimulated amylase secretion and the ability of the amino acid derivative to inhibit binding of 125 I-cholecystokinin. The inhibition of cholecystokinin-stimulated amylase secretion was competitive, fully reversible, and specific for those secretagogues that interact with the cholecystokinin receptor. The potencies with which the various carbobenzoxy amino acids inhibited the action of cholecystokinin varied 100-fold and CBZ-cystine was the most potent cholecystokinin receptor antagonist. This variation in potency was primarily but not exclusively a function of the hydrophobicity of the amino acid side chain

  6. Tsetse salivary gland proteins 1 and 2 are high affinity nucleic acid binding proteins with residual nuclease activity.

    Directory of Open Access Journals (Sweden)

    Guy Caljon

    Full Text Available Analysis of the tsetse fly salivary gland EST database revealed the presence of a highly enriched cluster of putative endonuclease genes, including tsal1 and tsal2. Tsal proteins are the major components of tsetse fly (G. morsitans morsitans saliva where they are present as monomers as well as high molecular weight complexes with other saliva proteins. We demonstrate that the recombinant tsetse salivary gland proteins 1&2 (Tsal1&2 display DNA/RNA non-specific, high affinity nucleic acid binding with K(D values in the low nanomolar range and a non-exclusive preference for duplex. These Tsal proteins exert only a residual nuclease activity with a preference for dsDNA in a broad pH range. Knockdown of Tsal expression by in vivo RNA interference in the tsetse fly revealed a partially impaired blood digestion phenotype as evidenced by higher gut nucleic acid, hematin and protein contents.

  7. Optimization of a Nucleic Acids united-RESidue 2-Point model (NARES-2P) with a maximum-likelihood approach

    International Nuclear Information System (INIS)

    He, Yi; Scheraga, Harold A.; Liwo, Adam

    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

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

    Science.gov (United States)

    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.

  9. Proteomic Investigation of Protein Profile Changes and Amino Acid Residue Level Modification in Cooked Lamb Meat: The Effect of Boiling.

    Science.gov (United States)

    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.

  10. Identification of functional amino acid residues involved in polyamine and agmatine transport by human organic cation transporter 2.

    Science.gov (United States)

    Higashi, Kyohei; Imamura, Masataka; Fudo, Satoshi; Uemura, Takeshi; Saiki, Ryotaro; Hoshino, Tyuji; Toida, Toshihiko; Kashiwagi, Keiko; Igarashi, Kazuei

    2014-01-01

    Polyamine (putrescine, spermidine and spermine) and agmatine uptake by the human organic cation transporter 2 (hOCT2) was studied using HEK293 cells transfected with pCMV6-XL4/hOCT2. The Km values for putrescine and spermidine were 7.50 and 6.76 mM, and the Vmax values were 4.71 and 2.34 nmol/min/mg protein, respectively. Spermine uptake by hOCT2 was not observed at pH 7.4, although it inhibited both putrescine and spermidine uptake. Agmatine was also taken up by hOCT2, with Km value: 3.27 mM and a Vmax value of 3.14 nmol/min/mg protein. Amino acid residues involved in putrescine, agmatine and spermidine uptake by hOCT2 were Asp427, Glu448, Glu456, Asp475, and Glu516. In addition, Glu524 and Glu530 were involved in putrescine and spermidine uptake activity, and Glu528 and Glu540 were weakly involved in putrescine uptake activity. Furthermore, Asp551 was also involved in the recognition of spermidine. These results indicate that the recognition sites for putrescine, agmatine and spermidine on hOCT2 strongly overlap, consistent with the observation that the three amines are transported with similar affinity and velocity. A model of spermidine binding to hOCT2 was constructed based on the functional amino acid residues.

  11. Identification of functional amino acid residues involved in polyamine and agmatine transport by human organic cation transporter 2.

    Directory of Open Access Journals (Sweden)

    Kyohei Higashi

    Full Text Available Polyamine (putrescine, spermidine and spermine and agmatine uptake by the human organic cation transporter 2 (hOCT2 was studied using HEK293 cells transfected with pCMV6-XL4/hOCT2. The Km values for putrescine and spermidine were 7.50 and 6.76 mM, and the Vmax values were 4.71 and 2.34 nmol/min/mg protein, respectively. Spermine uptake by hOCT2 was not observed at pH 7.4, although it inhibited both putrescine and spermidine uptake. Agmatine was also taken up by hOCT2, with Km value: 3.27 mM and a Vmax value of 3.14 nmol/min/mg protein. Amino acid residues involved in putrescine, agmatine and spermidine uptake by hOCT2 were Asp427, Glu448, Glu456, Asp475, and Glu516. In addition, Glu524 and Glu530 were involved in putrescine and spermidine uptake activity, and Glu528 and Glu540 were weakly involved in putrescine uptake activity. Furthermore, Asp551 was also involved in the recognition of spermidine. These results indicate that the recognition sites for putrescine, agmatine and spermidine on hOCT2 strongly overlap, consistent with the observation that the three amines are transported with similar affinity and velocity. A model of spermidine binding to hOCT2 was constructed based on the functional amino acid residues.

  12. Influence of residual elements in lead on oxygen- and hydrogen-gassing rates of lead-acid batteries

    Science.gov (United States)

    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.

  13. Blocking of proteolytic processing and deletion of glycosaminoglycan side chain of mouse DMP1 by substituting critical amino acid residues.

    Science.gov (United States)

    Peng, Tao; Huang, Bingzhen; Sun, Yao; Lu, Yongbo; Bonewald, Lynda; Chen, Shuo; Butler, William T; Feng, Jerry Q; D'Souza, Rena N; Qin, Chunlin

    2009-01-01

    Dentin matrix protein 1 (DMP1) is present in the extracellular matrix (ECM) of dentin and bone as processed NH(2)- and COOH-terminal fragments, resulting from proteolytic cleavage at the NH(2) termini of 4 aspartic acid residues during rat DMP1 processing. One cleavage site residue, Asp(181) (corresponding to Asp(197) of mouse DMP1), and its flanking region are highly conserved across species. We speculate that cleavage at the NH(2) terminus of Asp(197) of mouse DMP1 represents an initial, first-step scission in the whole cascade of proteolytic processing. To test if Asp(197) is critical for initiating the proteolytic processing of mouse DMP1, we substituted Asp(197) with Ala(197) by mutating the corresponding nucleotides of mouse cDNA that encode this amino acid residue. This mutant DMP1 cDNA was cloned into a pcDNA3.1 vector. Data from transfection experiments indicated that this single substitution blocked the proteolytic processing of mouse DMP1 in HEK-293 cells, indicating that cleavage at the NH(2) terminus of Asp(197) is essential for exposing other cleavage sites for the conversion of DMP1 to its fragments. The NH(2)-terminal fragment of DMP1 occurs as a proteoglycan form (DMP1-PG) that contains a glycosaminoglycan (GAG) chain. Previously, we showed that a GAG chain is linked to Ser(74) in rat DMP1 (Ser(89) in mouse DMP1). To confirm that mouse DMP1-PG possesses a single GAG chain attached to Ser(89), we substituted Ser(89) by Gly(89). Data from transfection analysis indicated that this substitution completely prevented formation of the GAG-containing form, confirming that DMP1-PG contains a single GAG chain attached to Ser(89) in mouse DMP1. Copyright 2008 S. Karger AG, Basel.

  14. Herpes Simplex Virus Type 1 Glycoprotein B Requires a Cysteine Residue at Position 633 for Folding, Processing, and Incorporation into Mature Infectious Virus Particles

    Science.gov (United States)

    Laquerre, Sylvie; Anderson, Dina B.; Argnani, Rafaela; Glorioso, Joseph C.

    1998-01-01

    Herpes simplex virus type 1 (HSV-1) glycoprotein B (gB) resides in the virus envelope in an oligomeric form and plays an essential role in virus entry into susceptible host cells. The oligomerizing domain is a movable element consisting of amino acids 626 to 653 in the gB external domain. This domain contains a single cysteine residue at position 633 (Cys-633) that is predicted to form an intramolecular disulfide bridge with Cys-596. In this study, we examined gB oligomerization, processing, and incorporation into mature virus during infection by two mutant viruses in which either the gB Cys-633 [KgB(C633S)] or both Cys-633 and Cys-596 [KgB(C596S/C633S)] residues were mutated to serine. The result of immunofluorescence studies and analyses of released virus particles showed that the mutant gB molecules were not transported to the cell surface or incorporated into mature virus envelopes and thus infectious virus was not produced. Immunoprecipitation studies revealed that the mutant gB molecules were in an oligomeric configuration and that these mutants produced hetero-oligomers with a truncated form of gB consisting of residues 1 to 43 and 595 to 904, the latter containing the oligomerization domain. Pulse-chase experiments in combination with endoglycosidase H treatment determined that the mutant molecules were improperly processed, having been retained in the endoplasmic reticulum (ER). Coimmunoprecipitation experiments revealed that the cysteine mutations resulted in gB misfolding and retention by the molecular chaperones calnexin, calreticulin, and Grp78 in the ER. The altered conformation of the gB mutant glycoproteins was directly detected by a reduction in monoclonal antibody recognition of two previously defined distinct antigenic sites located within residues 381 to 441 and 595 to 737. The misfolded molecules were not transported to the cell surface as hetero-oligomers with wild-type gB, suggesting that the conformational change could not be corrected by

  15. Waste management from reprocessing: a stringent regulatory requirements for high quality conditioned residues

    International Nuclear Information System (INIS)

    Bordier, J. C.; Greneche, D.; Devezeaux, J. G.; Dalcorso, J.

    2000-01-01

    Nuclear waste production and management in France is governed by safety requirements imposed to all operators. French nuclear safety relies on two basic principles: · Responsibility of the nuclear operator, which expands to waste generated, · Safety basic objectives issued by national Safety Authority. For a long time the regulatory framework for waste production and management has been satisfactorily applied and has benefited to each actor of the process. LLW/MLW and HLW nuclear waste are currently conditioned in safe matrices or packages either likely to be disposed in surface repositories or designed with the intention to be disposed underground according to their radioactive content. France is looking into the case of VLLW and has already carried out a design for future disposal, the design being in the pipe. Other types of waste (i. e. radium bearing waste, graphite, and tritium content waste) are also considered in the whole framework of French waste management. (author)

  16. 46 CFR 153.558 - Special requirements for phosphoric acid.

    Science.gov (United States)

    2010-10-01

    ... CARGOES SHIPS CARRYING BULK LIQUID, LIQUEFIED GAS, OR COMPRESSED GAS HAZARDOUS MATERIALS Design and... containment system must be: (a) Lined with natural rubber or neoprene; (b) Lined with a material approved for phosphoric acid tanks by the Commandant (CG-522); or (c) Made of a stainless steel that resists corrosion by...

  17. Vitamin C (ascorbic acid) requirements of Heterobranchus longifilis ...

    African Journals Online (AJOL)

    SERVER

    2007-07-04

    Jul 4, 2007 ... Fish fed the control (0 mg vitamin C kg-1) diet exhibited deficiency signs including lordosis, caudal fin deformity, ... INTRODUCTION. Vitamin C (ascorbic acid) belongs to the water-soluble group of vitamin. Its importance in fish diets and characteristics had been described by various authors. (Lim and Lovell ...

  18. Multiple Arginine Residues Are Methylated in Drosophila Mre11 and Required for Survival Following Ionizing Radiation.

    Science.gov (United States)

    Yuan, Qing; Tian, Ran; Zhao, Haiying; Li, Lijuan; Bi, Xiaolin

    2018-05-31

    Mre11 is a key player for DNA double strand break repair. Previous studies have shown that mammalian Mre11 is methylated at multiple arginines in its C-terminal Glycine-Arginine-Rich motif (GAR) by protein arginine methyltransferase PRMT1. Here, we found that the Drosophila Mre11 is methylated at arginines 559, 563, 565, and 569 in the GAR motif by DART1, the Drosophila homolog of PRMT1. Mre11 interacts with DART1 in S2 cells, and this interaction does not require the GAR motif. Arginines methylated Mre11 localizes exclusively in the nucleus as soluble nuclear protein or chromatin-binding protein. To study the in vivo functions of methylation, we generated the single Arg-Ala and all Arginines mutated flies. We found these mutants were sensitive to ionizing radiation. Furthermore, Arg-Ala mutated flies had no irradiation induced G2/M checkpoint defect in wing disc and eye disc. Thus, we provided evidence that arginines in Drosophila Mre11 are methylated by DART1 methytransferase and flies loss of arginine methylation are sensitive to irradiation. Copyright © 2018 Yuan et al.

  19. Carbonaceous materials in the acid residue from the Orgueil carbonaceous chondrite meteorite

    Science.gov (United States)

    Garvie, Laurence A. J.; Buseck, Peter R.

    2006-04-01

    Insoluble organic matter (IOM) dominates the HF/HCl residue of the Orgueil (CI) carbonaceous chondrite meteorite. The IOM is composed primarily of two C-rich particle types. The first has a fluffy texture similar to crumpled tissue paper, and the second type occurs as solid or hollow nanospheres. High-resolution transmission electron microscope (HRTEM) images of the fluffy material show it is poorly ordered, with small, irregularly shaped regions having fringes with 0.34-0.38 nm spacings and locally 0.21 nm cross-fringes. Nanodiamonds occur in the fluffy material. The rounded C-rich particles are common in the residue and their HRTEM images show neither fringes nor nanodiamonds. Both types of carbonaceous materials have a high aromatic component, as revealed by electron energy-loss spectroscopy (EELS), with up to 10 at% substitution by S, N, and O. The average compositions of the fluffy material and nanospheres are C100S1.9N3.7O4.9 and C100S2.4N5.0O3.9, respectively. The structural and chemical heterogeneity of the carbonaceous materials may represent material from multiple sources.

  20. Chemical-modification studies of a unique sialic acid-binding lectin from the snail Achatina fulica. Involvement of tryptophan and histidine residues in biological activity.

    Science.gov (United States)

    Basu, S; Mandal, C; Allen, A K

    1988-01-01

    A unique sialic acid-binding lectin, achatininH (ATNH) was purified in single step from the haemolymph of the snail Achatina fulica by affinity chromatography on sheep submaxillary-gland mucin coupled to Sepharose 4B. The homogeneity was checked by alkaline gel electrophoresis, immunodiffusion and immunoelectrophoresis. Amino acid analysis showed that the lectin has a fairly high content of acidic amino acid residues (22% of the total). About 1.3% of the residues are half-cystine. The glycoprotein contains 21% carbohydrate. The unusually high content of xylose (6%) and fucose (2.7%) in this snail lectin is quite interesting. The protein was subjected to various chemical modifications in order to detect the amino acid residues and carbohydrate residues present in its binding sites. Modification of tyrosine and arginine residues did not affect the binding activity of ATNH; however, modification of tryptophan and histidine residues led to a complete loss of its biological activity. A marked decrease in the fluorescence emission was found as the tryptophan residues of ATNH were modified. The c.d. data showed the presence of an identical type of conformation in the native and modified agglutinin. The modification of lysine and carboxy residues partially diminished the biological activity. The activity was completely lost after a beta-elimination reaction, indicating that the sugars are O-glycosidically linked to the glycoprotein's protein moiety. This result confirms that the carbohydrate moiety also plays an important role in the agglutination property of this lectin. Images Fig. 3. PMID:3140796

  1. [The importance of C-terminal aspartic acid residue (D141) to the antirestriction activity of the ArdB (R64) protein].

    Science.gov (United States)

    Kudryavtseva, A A; Osetrova, M S; Livinyuk, V Ya; Manukhov, I V; Zavilgelsky, G B

    2017-01-01

    Antirestriction proteins of the ArdB/KlcA family are specific inhibitors of restriction (endonuclease) activity of type-I restriction/modification enzymes. The effect of conserved amino acid residues on the antirestriction activity of the ArdB protein encoded by the transmissible R64 (IncI1) plasmid has been investigated. An analysis of the amino acid sequences of ArdB homologues demonstrated the presence of four groups of conserved residues ((1) R16, E32, and W51; (2) Y46 and G48; (3) S81, D83 and E132, and (4) N77, L(I)140, and D141) on the surface of the protein globule. Amino acid residues of the fourth group showed a unique localization pattern with the terminal residue protruding beyond the globule surface. The replacement of two conserved amino acids (D141 and N77) located in the close vicinity of each other on the globule surface showed that the C-terminal D141 is essential for the antirestriction activity of ArdB. The deletion of this residue, as well as replacement by a hydrophobic threonine residue (D141T), completely abolished the antirestriction activity of ArdB. The synonymous replacement of D141 by a glutamic acid residue (D141E) caused an approximately 30-fold decrease of the antirestriction activity of ArdB, and the point mutation N77A caused an approximately 20-fold decrease in activity. The residues D141 and N77 located on the surface of the protein globule are presumably essential for the formation of a contact between ArdB and a currently unknown factor that modulates the activity of type-I restriction/modification enzymes.

  2. Glutamic Acid Residues in HIV-1 p6 Regulate Virus Budding and Membrane Association of Gag.

    Science.gov (United States)

    Friedrich, Melanie; Setz, Christian; Hahn, Friedrich; Matthaei, Alina; Fraedrich, Kirsten; Rauch, Pia; Henklein, Petra; Traxdorf, Maximilian; Fossen, Torgils; Schubert, Ulrich

    2016-04-25

    The HIV-1 Gag p6 protein regulates the final abscission step of nascent virions from the cell membrane by the action of its two late (L-) domains, which recruit Tsg101 and ALIX, components of the ESCRT system. Even though p6 consists of only 52 amino acids, it is encoded by one of the most polymorphic regions of the HIV-1 gag gene and undergoes various posttranslational modifications including sumoylation, ubiquitination, and phosphorylation. In addition, it mediates the incorporation of the HIV-1 accessory protein Vpr into budding virions. Despite its small size, p6 exhibits an unusually high charge density. In this study, we show that mutation of the conserved glutamic acids within p6 increases the membrane association of Pr55 Gag followed by enhanced polyubiquitination and MHC-I antigen presentation of Gag-derived epitopes, possibly due to prolonged exposure to membrane bound E3 ligases. The replication capacity of the total glutamic acid mutant E0A was almost completely impaired, which was accompanied by defective virus release that could not be rescued by ALIX overexpression. Altogether, our data indicate that the glutamic acids within p6 contribute to the late steps of viral replication and may contribute to the interaction of Gag with the plasma membrane.

  3. Influence of washing time on residual contamination of carcasses sprayed with lauric acid-potassium hydroxide.

    Science.gov (United States)

    A series of experiments were conducted to examine reductions in bacterial contamination of broiler carcasses washed for various times in a spray cabinet with a 2% lauric acid (LA)-1% potassium hydroxide (KOH) (w/v) solution. Forty eviscerated carcasses and 5 ceca were obtained from the processing l...

  4. Effect of the replacement of aspartic acid/glutamic acid residues with asparagine/glutamine residues in RNase He1 from Hericium erinaceus on inhibition of human leukemia cell line proliferation.

    Science.gov (United States)

    Kobayashi, Hiroko; Motoyoshi, Naomi; Itagaki, Tadashi; Suzuki, Mamoru; Inokuchi, Norio

    2015-01-01

    RNase He1 from Hericium erinaceus, a member of the RNase T1 family, has high identity with RNase Po1 from Pleurotus ostreatus with complete conservation of the catalytic sequence. However, the optimal pH for RNase He1 activity is lower than that of RNase Po1, and the enzyme shows little inhibition of human tumor cell proliferation. Hence, to investigate the potential antitumor activity of recombinant RNase He1 and to possibly enhance its optimum pH, we generated RNase He1 mutants by replacing 12 Asn/Gln residues with Asp/Glu residues; the amino acid sequence of RNase Po1 was taken as reference. These mutants were then expressed in Escherichia coli. Using site-directed mutagenesis, we successfully modified the optimal pH for enzyme activity and generated a recombinant RNase He1 that inhibited the proliferation of cells in the human leukemia cell line. These properties are extremely important in the production of anticancer biologics that are based on RNase activity.

  5. The conserved basic residues and the charged amino acid residues at the α-helix of the zinc finger motif regulate the nuclear transport activity of triple C2H2 zinc finger proteins

    Science.gov (United States)

    Lin, Chih-Ying

    2018-01-01

    Zinc finger (ZF) motifs on proteins are frequently recognized as a structure for DNA binding. Accumulated reports indicate that ZF motifs contain nuclear localization signal (NLS) to facilitate the transport of ZF proteins into nucleus. We investigated the critical factors that facilitate the nuclear transport of triple C2H2 ZF proteins. Three conserved basic residues (hot spots) were identified among the ZF sequences of triple C2H2 ZF proteins that reportedly have NLS function. Additional basic residues can be found on the α-helix of the ZFs. Using the ZF domain (ZFD) of Egr-1 as a template, various mutants were constructed and expressed in cells. The nuclear transport activity of various mutants was estimated by analyzing the proportion of protein localized in the nucleus. Mutation at any hot spot of the Egr-1 ZFs reduced the nuclear transport activity. Changes of the basic residues at the α-helical region of the second ZF (ZF2) of the Egr-1 ZFD abolished the NLS activity. However, this activity can be restored by substituting the acidic residues at the homologous positions of ZF1 or ZF3 with basic residues. The restored activity dropped again when the hot spots at ZF1 or the basic residues in the α-helix of ZF3 were mutated. The variations in nuclear transport activity are linked directly to the binding activity of the ZF proteins with importins. This study was extended to other triple C2H2 ZF proteins. SP1 and KLF families, similar to Egr-1, have charged amino acid residues at the second (α2) and the third (α3) positions of the α-helix. Replacing the amino acids at α2 and α3 with acidic residues reduced the NLS activity of the SP1 and KLF6 ZFD. The reduced activity can be restored by substituting the α3 with histidine at any SP1 and KLF6 ZFD. The results show again the interchangeable role of ZFs and charge residues in the α-helix in regulating the NLS activity of triple C2H2 ZF proteins. PMID:29381770

  6. Effect of organic fertilizer and its residual on cowpea and soybean in acid soils

    Directory of Open Access Journals (Sweden)

    Henny Kuntyastuty

    2017-10-01

    Full Text Available The expansion of planting areas on acid soils is one of the strategies to achieve Indonesian self-sufficiency program on food. Acidic soil has low pH that causes contents of Al, Fe, and Mn are high. In addition, acidic soil also only has low microbial population. These conditions make soybean growth is not optimal. This research consisted of two phases i.e., the first and second planting. The first planting was aimed to study the effectiveness of fertilizer treatment, with three replications, using cowpea commodity. The second planting was done without additional fertilizer that consisted of three replicates (continued from the first planting using soybean. This research that was carried out at Iletri’s greenhouse Malang in 2014 was arranged in a randomized block design consisting of eight treatments, namely: (a control/without fertilizer; (B 300 kg/ha (15% N, 15% P2O5, 15% K2O, 10% S; (C 1500 kg/ha cow manure; (D 3000 kg/ha cow manure; (E 5000 kg/ha cow manure; (F 1500 kg/ha fermented chicken + cow manures; (G 3000 kg/ha fermented chicken + cow manures; and (H 5000 kg/ha fermented chicken + cow manures. The results showed that organic fertilizer (cow manure 5000 kg/ha had higher yields both in the first planting and second planting compared to inorganic fertilizer 300 kg/ha (15% N, 15% P2O5, 15% K2O, 10% S

  7. Purification, cloning, characterization and essential amino acid residues analysis of a new ι-carrageenase from Cellulophaga sp. QY3.

    Directory of Open Access Journals (Sweden)

    Su Ma

    Full Text Available ι-Carrageenases belong to family 82 of glycoside hydrolases that degrade sulfated galactans in the red algae known as ι-carrageenans. The catalytic mechanism and some substrate-binding residues of family GH82 have been studied but the substrate recognition and binding mechanism of this family have not been fully elucidated. We report here the purification, cloning and characterization of a new ι-carrageenase CgiA_Ce from the marine bacterium Cellulophaga sp. QY3. CgiA_Ce was the most thermostable carrageenase described so far. It was most active at 50°C and pH 7.0 and retained more than 70% of the original activity after incubation at 50°C for 1 h at pH 7.0 or at pH 5.0-10.6 for 24 h. CgiA_Ce was an endo-type ι-carrageenase; it cleaved ι-carrageenan yielding neo-ι-carrabiose and neo-ι-carratetraose as the main end products, and neo-ι-carrahexaose was the minimum substrate. Sequence analysis and structure modeling showed that CgiA_Ce is indeed a new member of family GH82. Moreover, sequence analysis of ι-carrageenases revealed that the amino acid residues at subsites -1 and +1 were more conserved than those at other subsites. Site-directed mutagenesis followed by kinetic analysis identified three strictly conserved residues at subsites -1 and +1 of ι-carrageenases, G228, Y229 and R254 in CgiA_Ce, which played important roles for substrate binding. Furthermore, our results suggested that Y229 and R254 in CgiA_Ce interacted specifically with the sulfate groups of the sugar moieties located at subsites -1 and +1, shedding light on the mechanism of ι-carrageenan recognition in the family GH82.

  8. A single acidic residue can guide binding site selection but does not govern QacR cationic-drug affinity.

    Directory of Open Access Journals (Sweden)

    Kate M Peters

    Full Text Available Structures of the multidrug-binding repressor protein QacR with monovalent and bivalent cationic drugs revealed that the carboxylate side-chains of E90 and E120 were proximal to the positively charged nitrogens of the ligands ethidium, malachite green and rhodamine 6G, and therefore may contribute to drug neutralization and binding affinity. Here, we report structural, biochemical and in vivo effects of substituting these glutamate residues. Unexpectedly, substitutions had little impact on ligand affinity or in vivo induction capabilities. Structures of QacR(E90Q and QacR(E120Q with ethidium or malachite green took similar global conformations that differed significantly from all previously described QacR-drug complexes but still prohibited binding to cognate DNA. Strikingly, the QacR(E90Q-rhodamine 6G complex revealed two mutually exclusive rhodamine 6G binding sites. Despite multiple structural changes, all drug binding was essentially isoenergetic. Thus, these data strongly suggest that rather than contributing significantly to ligand binding affinity, the role of acidic residues lining the QacR multidrug-binding pocket is primarily to attract and guide cationic drugs to the "best available" positions within the pocket that elicit QacR induction.

  9. Identification of genetic determinants and enzymes involved with the amidation of glutamic acid residues in the peptidoglycan of Staphylococcus aureus.

    Directory of Open Access Journals (Sweden)

    Teresa A Figueiredo

    2012-01-01

    Full Text Available The glutamic acid residues of the peptidoglycan of Staphylococcus aureus and many other bacteria become amidated by an as yet unknown mechanism. In this communication we describe the identification, in the genome of S. aureus strain COL, of two co-transcribed genes, murT and gatD, which are responsible for peptidoglycan amidation. MurT and GatD have sequence similarity to substrate-binding domains in Mur ligases (MurT and to the catalytic domain in CobB/CobQ-like glutamine amidotransferases (GatD. The amidation of glutamate residues in the stem peptide of S. aureus peptidoglycan takes place in a later step than the cytoplasmic phase--presumably the lipid phase--of the biosynthesis of the S. aureus cell wall precursor. Inhibition of amidation caused reduced growth rate, reduced resistance to beta-lactam antibiotics and increased sensitivity to lysozyme which inhibited culture growth and caused degradation of the peptidoglycan.

  10. Determination of cyanuric acid residues in catfish, trout, tilapia, salmon and shrimp by liquid chromatography-tandem mass spectrometry

    International Nuclear Information System (INIS)

    Karbiwnyk, Christine M.; Andersen, Wendy C.; Turnipseed, Sherri B.; Storey, Joseph M.; Madson, Mark R.; Miller, Keith E.; Gieseker, Charles M.; Miller, Ron A.; Rummel, Nathan G.; Reimschuessel, Renate

    2009-01-01

    In May 2007, investigators discovered that waste material from the pet food manufacturing process contaminated with melamine (MEL) and/or cyanuric acid (CYA) had been added to hog and chicken feeds. At this time, investigators also learned that adulterated wheat gluten had been used in the manufacture of aquaculture feeds. Concern that the contaminated feed had been used in aquaculture and could enter the human food supply prompted the development of a method for the determination of CYA residues in the edible tissues of fish and shrimp. Liquid chromatography-tandem mass spectrometry (LC-MS/MS) was employed as a sensitive technique for the analysis of CYA in catfish, tilapia, salmon, trout and shrimp tissue. CYA was extracted from ground fish or shrimp with an acetic acid solution, defatted with hexane, and isolated with a graphitic carbon black solid-phase extraction column. Residues were separated from matrix components using a porous graphitic carbon LC column, and then analyzed with electrospray ionization in negative ion mode on a triple quadrupole mass spectrometer. Selective reaction monitoring was performed on the [M-H] - m/z 128 ion resulting in the product ions m/z 85 and 42. Recoveries from catfish, tilapia and trout fortified with 10-100 μg kg -1 of CYA averaged 67% with a relative standard deviation (R.S.D.) of 18% (n = 107). The average method detection limit (MDL) for catfish, tilapia and trout is 3.5 μg kg -1 . An internal standard, 13 C 3 -labeled CYA, was used in the salmon and shrimp extractions. Average recovery of CYA from salmon was 91% (R.S.D. = 15%, n = 18) with an MDL of 7.4 μg kg -1 . Average recovery of CYA from shrimp was 85% (R.S.D. = 10%, n = 13) with an MDL of 3.5 μg kg -1

  11. Antibacterial Properties of Silver Nanoparticles Embedded on Polyelectrolyte Hydrogels Based on α-Amino Acid Residues

    Directory of Open Access Journals (Sweden)

    Mario Casolaro

    2018-05-01

    Full Text Available Polyelectrolyte hydrogels bearing l-phenylalanine (PHE, l-valine (AVA, and l-histidine (Hist residues were used as scaffolds for the formation of silver nanoparticles by reduction of Ag+ ions with NaBH4. The interaction with the metal ion allowed a prompt collapse of the swollen hydrogel, due to the neutralization reaction of basic groups present on the polymer. The imidazole nitrogen of the hydrogel with Hist demonstrated greater complexing capacity with the Ag+ ion compared to the hydrogels with carboxyl groups. The subsequent reduction to metallic silver allowed for the restoration of the hydrogel’s degree of swelling to the starting value. Transmission electron microscopy (TEM and spectroscopic analyses showed, respectively, a uniform distribution of the 15 nm spherical silver nanoparticles embedded on the hydrogel and peak optical properties around a wavelength of 400 nm due to the surface plasmonic effect. Unlike native hydrogels, the composite hydrogels containing silver nanoparticles showed good antibacterial activity as gram+/gram− bactericides, and higher antifungal activity against S. cerevisiae.

  12. Amino acid residues that contribute to substrate specificity of class A beta-lactamase SME-1.

    Science.gov (United States)

    Majiduddin, Fahd K; Palzkill, Timothy

    2005-08-01

    Carbapenem antibiotics are used as antibiotics of last resort because they possess a broad spectrum of antimicrobial activity and are not easily hydrolyzed by beta-lactamases. Recently, class A enzymes, such as the SME-1, NMC-A, and IMI-1 beta-lactamases, have been identified with the capacity to hydrolyze carbapenem antibiotics. Traditional class A beta-lactamases, such as TEM-1 and SHV-1, are unable to hydrolyze carbapenem antibiotics and exhibit some differences in sequence from those that are able to hydrolyze carbapenem antibiotics. The positions that differ may contribute to the unique substrate specificity of the class A carbapenemase SME-1. Codons in the SME-1 gene representing residues 104, 105, 132, 167, 237, and 241 were randomized by site-directed mutagenesis, and functional mutants were selected for the ability to hydrolyze imipenem, ampicillin, or cefotaxime. Although several positions are important for hydrolysis of beta-lactam antibiotics, no single position was found to uniquely contribute to carbapenem hydrolysis. The results of this study support a model whereby the carbapenemase activity of SME-1 is due to a highly distributed set of interactions that subtly alter the structure of the active-site pocket.

  13. Amino Acid Residues That Contribute to Substrate Specificity of Class A β-Lactamase SME-1

    Science.gov (United States)

    Majiduddin, Fahd K.; Palzkill, Timothy

    2005-01-01

    Carbapenem antibiotics are used as antibiotics of last resort because they possess a broad spectrum of antimicrobial activity and are not easily hydrolyzed by β-lactamases. Recently, class A enzymes, such as the SME-1, NMC-A, and IMI-1 β-lactamases, have been identified with the capacity to hydrolyze carbapenem antibiotics. Traditional class A β-lactamases, such as TEM-1 and SHV-1, are unable to hydrolyze carbapenem antibiotics and exhibit some differences in sequence from those that are able to hydrolyze carbapenem antibiotics. The positions that differ may contribute to the unique substrate specificity of the class A carbapenemase SME-1. Codons in the SME-1 gene representing residues 104, 105, 132, 167, 237, and 241 were randomized by site-directed mutagenesis, and functional mutants were selected for the ability to hydrolyze imipenem, ampicillin, or cefotaxime. Although several positions are important for hydrolysis of β-lactam antibiotics, no single position was found to uniquely contribute to carbapenem hydrolysis. The results of this study support a model whereby the carbapenemase activity of SME-1 is due to a highly distributed set of interactions that subtly alter the structure of the active-site pocket. PMID:16048956

  14. Vitamin C (ascorbic acid) requirements of Heterobranchus longifilis ...

    African Journals Online (AJOL)

    A feeding experiment was conducted to quantify the minimum dietary vitamin C requirement of Heterobranchus longifilis fingerlings. Fish were fed a basal diet with 42.5% crude protein for a conditioning period of 2 weeks. Following conditioning, fingerlings with initial mean weight, 2.3 ± 0.3 g were stocked as groups of 20 ...

  15. Models of protein and amino acid requirements for cattle

    Directory of Open Access Journals (Sweden)

    Luis Orlindo Tedeschi

    2015-03-01

    Full Text Available Protein supply and requirements by ruminants have been studied for more than a century. These studies led to the accumulation of lots of scientific information about digestion and metabolism of protein by ruminants as well as the characterization of the dietary protein in order to maximize animal performance. During the 1980s and 1990s, when computers became more accessible and powerful, scientists began to conceptualize and develop mathematical nutrition models, and to program them into computers to assist with ration balancing and formulation for domesticated ruminants, specifically dairy and beef cattle. The most commonly known nutrition models developed during this period were the National Research Council (NRC in the United States, Agricultural Research Council (ARC in the United Kingdom, Institut National de la Recherche Agronomique (INRA in France, and the Commonwealth Scientific and Industrial Research Organization (CSIRO in Australia. Others were derivative works from these models with different degrees of modifications in the supply or requirement calculations, and the modeling nature (e.g., static or dynamic, mechanistic, or deterministic. Circa 1990s, most models adopted the metabolizable protein (MP system over the crude protein (CP and digestible CP systems to estimate supply of MP and the factorial system to calculate MP required by the animal. The MP system included two portions of protein (i.e., the rumen-undegraded dietary CP - RUP - and the contributions of microbial CP - MCP as the main sources of MP for the animal. Some models would explicitly account for the impact of dry matter intake (DMI on the MP required for maintenance (MPm; e.g., Cornell Net Carbohydrate and Protein System - CNCPS, the Dutch system - DVE/OEB, while others would simply account for scurf, urinary, metabolic fecal, and endogenous contributions independently of DMI. All models included milk yield and its components in estimating MP required for lactation

  16. Dilute Sulfuric Acid Pretreatment of Agricultural and Agro-Industrial Residues for Ethanol Production

    Science.gov (United States)

    Martin, Carlos; Alriksson, Björn; Sjöde, Anders; Nilvebrant, Nils-Olof; Jönsson, Leif J.

    The potential of dilute-acid prehydrolysis as a pretreatment method for sugarcane bagasse, rice hulls, peanut shells, and cassava stalks was investigated. The prehydrolysis was performed at 122°C during 20, 40, or 60 min using 2% H2SO4 at a solid-to-liquid ratio of 1∶10. Sugar formation increased with increasing reaction time. Xylose, glucose, arabinose, and galactose were detected in all of the prehydrolysates, whereas mannose was found only in the prehydrolysates of peanut shells and cassava stalks. The hemicelluloses of bagasse were hydrolyzed to a high-extent yielding concentrations of xylose and arabinose of 19.1 and 2.2 g/L, respectively, and a xylan conversion of more than 80%. High-glucose concentrations (26-33.5 g/L) were found in the prehydrolysates of rice hulls, probably because of hydrolysis of starch of grain remains in the hulls. Peanut shells and cassava stalks rendered low amounts of sugars on prehydrolysis, indicating that the conditions were not severe enough to hydrolyze the hemicelluloses in these materials quantitatively. All prehydrolysates were readily fermentable by Saccharomyces cerevisiae. The dilute-acid prehydrolysis resulted in a 2.7-to 3.7-fold increase of the enzymatic convertibility of bagasse, but was not efficient for improving the enzymatic hydrolysis of peanut shells, cassava stalks, or rice hulls.

  17. Predicting HLA class I non-permissive amino acid residues substitutions.

    Directory of Open Access Journals (Sweden)

    T Andrew Binkowski

    Full Text Available Prediction of peptide binding to human leukocyte antigen (HLA molecules is essential to a wide range of clinical entities from vaccine design to stem cell transplant compatibility. Here we present a new structure-based methodology that applies robust computational tools to model peptide-HLA (p-HLA binding interactions. The method leverages the structural conservation observed in p-HLA complexes to significantly reduce the search space and calculate the system's binding free energy. This approach is benchmarked against existing p-HLA complexes and the prediction performance is measured against a library of experimentally validated peptides. The effect on binding activity across a large set of high-affinity peptides is used to investigate amino acid mismatches reported as high-risk factors in hematopoietic stem cell transplantation.

  18. Wastewater disinfection by peracetic acid: assessment of models for tracking residual measurements and inactivation.

    Science.gov (United States)

    Santoro, Domenico; Gehr, Ronald; Bartrand, Timothy A; Liberti, Lorenzo; Notarnicola, Michele; Dell'Erba, Adele; Falsanisi, Dario; Haas, Charles N

    2007-07-01

    With its potential for low (if any) disinfection byproduct formation and easy retrofit for chlorine contactors, peracetic acid (PAA) or use of PAA in combination with other disinfectant technologies may be an attractive alternative to chlorine-based disinfection. Examples of systems that might benefit from use of PAA are water reuse schemes or plants discharging to sensitive receiving water bodies. Though PAA is in use in numerous wastewater treatment plants in Europe, its chemical kinetics, microbial inactivation rates, and mode of action against microorganisms are not thoroughly understood. This paper presents results from experimental studies of PAA demand, PAA decay, and microbial inactivation, with a complementary modeling analysis. Model results are used to evaluate techniques for measurement of PAA concentration and to develop hypotheses regarding the mode of action of PAA in bacterial inactivation. Kinetic and microbial inactivation rate data were collected for typical wastewaters and may be useful for engineers in evaluating whether to convert from chlorine to PAA disinfection.

  19. Stainless steels with low contents in residual elements for nitric acid environments. Influence of melting processes

    International Nuclear Information System (INIS)

    Desestret, A.; Gay, G.; Soulignac, P.

    1983-01-01

    Nitric acid solutions, as they are for instance employed in the chemical treatment of nuclear fuels, do not apparently pose any more corrosion problems and the safe use of the several steels is well documented. The most difficult corrosion problems are next those related to ''tunnel'' penetrations, in the hot-rolling direction (longitudinal). This phenomenon can be quite important such as to imperial complex structures. Up to the last few years, the only manner to eliminate such ''tunnel'' corrosions was to carry out special operations of remelting and refining under careful selected slag (Electro Slag Remelting or ESR). It turns out indeed that non metallic inclusions are the prime factors in this type of corrosion. Well adapted ladle refining processes made possible to obtain equivalent results at lower costs, while purity and cleanliness are improved to such a degree that a steel of type Cr 18 - Ni 10 thus produced exhibit a nearly absolute resistance to intergranular corrosion in the 14 N (65%) boiling nitric acid (the Huey test) whatever the ''sensitization'' treatment, between 1000 0 C and 600 0 C. In view of its very high tolerance to varied thermal cycles and of the near complete disappearance of any ''tunnel'' corrosion, such a steel is of great interest when complex parts are produced, by machining forged or rolled metal, which is then assembled by welding techniques or procedures which would be forbidden in the case of usual Cr 18 -Ni 10 steels. Similar improvements are also obtained on the two other special steels used in nitric environments: Cr 25 - Ni 20 - C [fr

  20. Involvement of tyrosine residues, N-terminal amino acids, and beta-alanine in insect cuticular sclerotization.

    Science.gov (United States)

    Andersen, Svend Olav

    2007-09-01

    During sclerotization of insect cuticle the acyldopamines, N-acetyldopamine (NADA) and N-beta-alanyldopamine (NBAD), are oxidatively incorporated into the cuticular matrix, thereby hardening and stabilizing the material by forming crosslinks between the proteins in the cuticular matrix and by forming polymers filling the intermolecular spaces in the cuticle. Sclerotized cuticle from the locust, Schistocerca gregaria, and the beetle, Tenebrio molitor, was hydrolyzed in dilute hydrochloric acid, and from the hydrolysates some components presumably degradation products of cuticular crosslinks were isolated. In two of the components, the sidechain of 3,4-dihydroxyacetophenone was linked to the amino groups of glycine and beta-alanine, respectively, and in the third component to the phenolic group of tyrosine. These three compounds, glycino-dihydroxyacetophenone, beta-alanino-dihydroxyacetophenone, and O-tyrosino-dihydroxyacetophenone, as well as the previously reported compound, lysino-dihydroxyacetophenone [Andersen, S.O., Roepstorff, P., 2007. Aspects of cuticular sclerotization in the locust, Schistocerca gregaria, and the beetle, Tenebrio molitor. Insect Biochem. Mol. Biol. 37, 223-234], are suggested to be degradation products of cuticular crosslinks, in which amino acid residues formed linkages to both the alpha- and beta-positions of the sidechain of acyldopamines.

  1. Identification of key amino acid residues in the hTGR5-nomilin interaction and construction of its binding model.

    Science.gov (United States)

    Sasaki, Takashi; Mita, Moeko; Ikari, Naho; Kuboyama, Ayane; Hashimoto, Shuzo; Kaneko, Tatsuya; Ishiguro, Masaji; Shimizu, Makoto; Inoue, Jun; Sato, Ryuichiro

    2017-01-01

    TGR5, a member of the G protein-coupled receptor (GPCR) family, is activated by bile acids. Because TGR5 promotes energy expenditure and improves glucose homeostasis, it is recognized as a key target in treating metabolic diseases. We previously showed that nomilin, a citrus limonoid, activates TGR5 and confers anti-obesity and anti-hyperglycemic effects in mice. Information on the TGR5-nomilin interaction regarding molecular structure, however, has not been reported. In the present study, we found that human TGR5 (hTGR5) shows higher nomilin responsiveness than does mouse TGR5 (mTGR5). Using mouse-human chimeric TGR5, we also found that three amino acid residues (Q77ECL1, R80ECL1, and Y893.29) are important in the hTGR5-nomilin interaction. Based on these results, an hTGR5-nomilin binding model was constructed using in silico docking simulation, demonstrating that four hydrophilic hydrogen-bonding interactions occur between nomilin and hTGR5. The binding mode of hTGR5-nomilin is vastly different from those of other TGR5 agonists previously reported, suggesting that TGR5 forms various binding patterns depending on the type of agonist. Our study promotes a better understanding of the structure of TGR5, and it may be useful in developing and screening new TGR5 agonists.

  2. Requirement of tyrosine residues 333 and 338 of the growth hormone (GH) receptor for selected GH-stimulated function

    DEFF Research Database (Denmark)

    Lobie, P E; Allevato, G; Norstedt, G

    1995-01-01

    We have examined the involvement of tyrosine residues 333 and 338 of the growth hormone (GH) receptor in the cellular response to GH. Stable Chinese hamster ovary (CHO) cell clones expressing a receptor with tyrosine residues at position 333 and 338 of the receptor substituted for phenylalanine (...

  3. Oxidation of protein tyrosine or methionine residues: From the amino acid to the peptide

    Energy Technology Data Exchange (ETDEWEB)

    Berges, J [Universite Pierre et Marie Curie, UMR 7616, Laboratoire de Chimie Theorique, 75005 Paris (France); Trouillas, P [EA 4021 Faculte de Pharmacie, 2 Rue du Dr. Marcland, 87025 Limoges Cedex (France); Houee-Levin, C, E-mail: jb@lct.jussieu.fr, E-mail: patrick.trouillas@unilim.fr, E-mail: chantal.houee@u-psud.fr [Universite Paris Sud, UMR 8000, Laboratoire de Chimie Physique, 91405 Orsay (France) (France)

    2011-01-01

    Methionine and tyrosine are competing targets of oxidizing free radicals in peptides or proteins. The first step is the addition of OH radicals either on the sulphur atom of methionine, followed by OH{sup -} elimination, or on the aromatic cycle of tyrosine. The next step can be stabilization of methionine radical cation by a two centre-three electron bond, or intramolecular electron transfer from tyrosine to the methionine radical cation. In this latter case a tyrosine radical is formed, which appears deprotonated. In a first step we have compared the stability of the OH radical adducts on Methionine or on Tyrosine. In agreement with experimental results, the thermodynamical data indicate that the OH adduct on Tyrosine and the radical cation are more stable than those on methionine. In a second step we have investigated the stabilization of the radical cations of Methionine by formation of intramolecular S:X two-center three-electron bond (X=S, N, O). Finally we have compared the spin densities on separated amino acids to that in a radical pentapeptide, methionine enkephalin. One observes a delocalisation of the orbital of the odd electron on the sulfur atom of Met and on the cycle of Tyr. The peptidic chain is also concerned.

  4. Oxidation of protein tyrosine or methionine residues: From the amino acid to the peptide

    International Nuclear Information System (INIS)

    Berges, J; Trouillas, P; Houee-Levin, C

    2011-01-01

    Methionine and tyrosine are competing targets of oxidizing free radicals in peptides or proteins. The first step is the addition of OH radicals either on the sulphur atom of methionine, followed by OH - elimination, or on the aromatic cycle of tyrosine. The next step can be stabilization of methionine radical cation by a two centre-three electron bond, or intramolecular electron transfer from tyrosine to the methionine radical cation. In this latter case a tyrosine radical is formed, which appears deprotonated. In a first step we have compared the stability of the OH radical adducts on Methionine or on Tyrosine. In agreement with experimental results, the thermodynamical data indicate that the OH adduct on Tyrosine and the radical cation are more stable than those on methionine. In a second step we have investigated the stabilization of the radical cations of Methionine by formation of intramolecular S:X two-center three-electron bond (X=S, N, O). Finally we have compared the spin densities on separated amino acids to that in a radical pentapeptide, methionine enkephalin. One observes a delocalisation of the orbital of the odd electron on the sulfur atom of Met and on the cycle of Tyr. The peptidic chain is also concerned.

  5. The conserved glycine residues in the transmembrane domain of the Semliki Forest virus fusion protein are not required for assembly and fusion

    International Nuclear Information System (INIS)

    Liao Maofu; Kielian, Margaret

    2005-01-01

    The alphavirus Semliki Forest virus (SFV) infects cells via a low pH-triggered fusion reaction mediated by the viral E1 protein. Both the E1 fusion peptide and transmembrane (TM) domain are essential for membrane fusion, but the functional requirements for the TM domain are poorly understood. Here we explored the role of the five TM domain glycine residues, including the highly conserved glycine pair at E1 residues 415/416. SFV mutants with alanine substitutions for individual or all five glycine residues (5G/A) showed growth kinetics and fusion pH dependence similar to those of wild-type SFV. Mutants with increasing substitution of glycine residues showed an increasingly more stringent requirement for cholesterol during fusion. The 5G/A mutant showed decreased fusion kinetics and extent in fluorescent lipid mixing assays. TM domain glycine residues thus are not required for efficient SFV fusion or assembly but can cause subtle effects on the properties of membrane fusion

  6. Influence of calcium and phosphorus, lactose, and salt-to-moisture ratio on Cheddar cheese quality: changes in residual sugars and water-soluble organic acids during ripening.

    Science.gov (United States)

    Upreti, P; McKay, L L; Metzger, L E

    2006-02-01

    Cheddar cheese ripening involves the conversion of lactose to glucose and galactose or galactose-6-phosphate by starter and nonstarter lactic acid bacteria. Under ideal conditions (i.e., where bacteria grow under no stress of pH, water activity, and salt), these sugars are mainly converted to lactic acid. However, during ripening of cheese, survival and growth of bacteria occurs under the stressed condition of low pH, low water activity, and high salt content. This forces bacteria to use alternate biochemical pathways resulting in production of other organic acids. The objective of this study was to determine if the level and type of organic acids produced during ripening was influenced by calcium (Ca) and phosphorus (P), residual lactose, and salt-to-moisture ratio (S/M) of cheese. Eight cheeses with 2 levels of Ca and P (0.67 and 0.47% vs. 0.53 and 0.39%, respectively), lactose at pressing (2.4 vs. 0.78%), and S/M (6.4 vs. 4.8%) were manufactured. The cheeses were analyzed for organic acids (citric, orotic, pyruvic, lactic, formic, uric, acetic, propanoic, and butyric acids) and residual sugars (lactose, galactose) during 48 wk of ripening using an HPLC-based method. Different factors influenced changes in concentration of residual sugars and organic acids during ripening and are discussed in detail. Our results indicated that the largest decrease in lactose and the largest increase in lactic acid occurred between salting and d 1 of ripening. It was interesting to observe that although the lactose content in cheese was influenced by several factors (Ca and P, residual lactose, and S/M), the concentration of lactic acid was influenced only by S/M. More lactic acid was produced in low S/M treatments compared with high S/M treatments. Although surprising for Cheddar cheese, a substantial amount (0.2 to 0.4%) of galactose was observed throughout ripening in all treatments. Minor changes in the levels of citric, uric, butyric, and propanoic acids were observed during

  7. Modulation of procaspase-7 self-activation by PEST amino acid residues of the N-terminal prodomain and intersubunit linker.

    Science.gov (United States)

    Alves, Juliano; Garay-Malpartida, Miguel; Occhiucci, João M; Belizário, José E

    2017-12-01

    Procaspase-7 zymogen polypeptide is composed of a short prodomain, a large subunit (p20), and a small subunit (p10) connected to an intersubunit linker. Caspase-7 is activated by an initiator caspase-8 and -9, or by autocatalysis after specific cleavage at IQAD 198 ↓S located at the intersubunit linker. Previously, we identified that PEST regions made of amino acid residues Pro (P), Glu (E), Asp (D), Ser (S), Thr (T), Asn (N), and Gln (Q) are conserved flanking amino acid residues in the cleavage sites within a prodomain and intersubunit linker of all caspase family members. Here we tested the impact of alanine substitution of PEST amino acid residues on procaspase-7 proteolytic self-activation directly in Escherichia coli. The p20 and p10 subunit cleavage were significantly delayed in double caspase-7 mutants in the prodomain (N18A/P26A) and intersubunit linker (S199A/P201A), compared with the wild-type caspase-7. The S199A/P201A mutants effectively inhibited the p10 small subunit cleavage. However, the mutations did not change the kinetic parameters (k cat /K M ) and optimal tetrapeptide specificity (DEVD) of the purified mutant enzymes. The results suggest a role of PEST-amino acid residues in the molecular mechanism for prodomain and intersubunit cleavage and caspase-7 self-activation.

  8. Evaluation of crop residues on potassium kinetics in an acid soil and potassium use efficiency in potato-garlic sequence using tracer 86Rb

    International Nuclear Information System (INIS)

    Sud, K.C.

    2005-01-01

    Greenhouse and laboratory studies were conducted on an acid soil in order to evaluate the role of two crop residues i.e. paddy and wheat along with farmyard manure on potassium kinetics and its availability in the potato-garlic sequence using tracer 86 Rb. Under rapid equilibrium, application of crop residues of paddy, wheat straw and FYM were able to enhance soil pH and organic carbon content. In addition, their application helped in enhancing soil K availability indices like water soluble, available and non-exchangeable -K. This was further augmented by the Q/I studies using 86 Rb where application of organic residues helped in lowering the potassium buffering capacity of the soil. Greenhouse study supplemented the results obtained from laboratory study where application of crop residues/FYM were able to improve the potato yield significantly and maintained higher concentration of K in potato leaf at early growth stages. A significant correlation was obtained between leaf K and haulms-K with that of 86 Rb activities in potato leaf at 35 days and 86 Rb absorbed in the haulms, respectively. Residues/ FYM and PK application to potato left sufficient residual effect on succeeding garlic crop. In potato-garlic sequence, K recovery was highest with FYM while N and P recoveries were higher with wheat residues. The nutrient recoveries with PK application followed law of diminishing returns. (author)

  9. The Distribution of Charged Amino Acid Residues and the Ca2+ Permeability of Nicotinic Acetylcholine Receptors: A Predictive Model

    Directory of Open Access Journals (Sweden)

    Sergio Fucile

    2017-05-01

    Full Text Available Nicotinic acetylcholine receptors (nAChRs are cation-selective ligand-gated ion channels exhibiting variable Ca2+ permeability depending on their subunit composition. The Ca2+ permeability is a crucial functional parameter to understand the physiological role of nAChRs, in particular considering their ability to modulate Ca2+-dependent processes such as neurotransmitter release. The rings of extracellular and intracellular charged amino acid residues adjacent to the pore-lining TM2 transmembrane segment have been shown to play a key role in the cation selectivity of these receptor channels, but to date a quantitative relationship between these structural determinants and the Ca2+ permeability of nAChRs is lacking. In the last years the Ca2+ permeability of several nAChR subtypes has been experimentally evaluated, in terms of fractional Ca2+ current (Pf, i.e., the percentage of the total current carried by Ca2+ ions. In the present study, the available Pf-values of nAChRs are used to build a simplified modular model describing the contribution of the charged residues in defined regions flanking TM2 to the selectivity filter controlling Ca2+ influx. This model allows to predict the currently unknown Pf-values of existing nAChRs, as well as the hypothetical Ca2+ permeability of subunit combinations not able to assemble into functional receptors. In particular, basing on the amino acid sequences, a Pf > 50% would be associated with homomeric nAChRs composed by different α subunits, excluding α7, α9, and α10. Furthermore, according to the model, human α7β2 receptors should have Pf-values ranging from 3.6% (4:1 ratio to 0.1% (1:4 ratio, much lower than the 11.4% of homomeric α7 nAChR. These results help to understand the evolution and the function of the large diversity of the nicotinic receptor family.

  10. Determination of cyanuric acid residues in catfish, trout, tilapia, salmon and shrimp by liquid chromatography-tandem mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Karbiwnyk, Christine M. [Animal Drugs Research Center, U.S. Food and Drug Administration, P.O. Box 25087, Denver, CO 80225-0087 (United States)], E-mail: christine.karbiwnyk@fda.hhs.gov; Andersen, Wendy C.; Turnipseed, Sherri B. [Animal Drugs Research Center, U.S. Food and Drug Administration, P.O. Box 25087, Denver, CO 80225-0087 (United States); Storey, Joseph M.; Madson, Mark R. [Denver District Laboratory, U.S. Food and Drug Administration, P.O. Box 25087, Denver, CO 80225-0087 (United States); Miller, Keith E. [Center for Veterinary Medicine, U.S. Food and Drug Administration, 8401 Muirkirk Road, Laurel, MD 20708 (United States); Gieseker, Charles M.; Miller, Ron A.; Rummel, Nathan G.; Reimschuessel, Renate [University of Denver, Department of Chemistry and Biochemistry, Denver, CO 80208 (United States)

    2009-04-01

    In May 2007, investigators discovered that waste material from the pet food manufacturing process contaminated with melamine (MEL) and/or cyanuric acid (CYA) had been added to hog and chicken feeds. At this time, investigators also learned that adulterated wheat gluten had been used in the manufacture of aquaculture feeds. Concern that the contaminated feed had been used in aquaculture and could enter the human food supply prompted the development of a method for the determination of CYA residues in the edible tissues of fish and shrimp. Liquid chromatography-tandem mass spectrometry (LC-MS/MS) was employed as a sensitive technique for the analysis of CYA in catfish, tilapia, salmon, trout and shrimp tissue. CYA was extracted from ground fish or shrimp with an acetic acid solution, defatted with hexane, and isolated with a graphitic carbon black solid-phase extraction column. Residues were separated from matrix components using a porous graphitic carbon LC column, and then analyzed with electrospray ionization in negative ion mode on a triple quadrupole mass spectrometer. Selective reaction monitoring was performed on the [M-H]{sup -}m/z 128 ion resulting in the product ions m/z 85 and 42. Recoveries from catfish, tilapia and trout fortified with 10-100 {mu}g kg{sup -1} of CYA averaged 67% with a relative standard deviation (R.S.D.) of 18% (n = 107). The average method detection limit (MDL) for catfish, tilapia and trout is 3.5 {mu}g kg{sup -1}. An internal standard, {sup 13}C{sub 3}-labeled CYA, was used in the salmon and shrimp extractions. Average recovery of CYA from salmon was 91% (R.S.D. = 15%, n = 18) with an MDL of 7.4 {mu}g kg{sup -1}. Average recovery of CYA from shrimp was 85% (R.S.D. = 10%, n = 13) with an MDL of 3.5 {mu}g kg{sup -1}.

  11. 12 CFR 714.5 - What is required if you rely on an estimated residual value greater than 25% of the original cost...

    Science.gov (United States)

    2010-01-01

    ... 12 Banks and Banking 6 2010-01-01 2010-01-01 false What is required if you rely on an estimated residual value greater than 25% of the original cost of the leased property? 714.5 Section 714.5 Banks and Banking NATIONAL CREDIT UNION ADMINISTRATION REGULATIONS AFFECTING CREDIT UNIONS LEASING § 714.5 What is...

  12. Separating nano graphene oxide from the residual strong-acid filtrate of the modified Hummers method with alkaline solution

    Energy Technology Data Exchange (ETDEWEB)

    Hu, Xuebing, E-mail: xuebinghu2010@gmail.com [Key Laboratory of Inorganic Membrane, Jingdezhen Ceramic Institute, Jingdezhen 333001 (China); Key Laboratory of Inorganic Coating Materials, Shanghai Institute of Ceramics, Chinese Academy of Science, Shanghai 201800 (China); Yu, Yun, E-mail: yunyush@mail.sic.ac.cn [Key Laboratory of Inorganic Coating Materials, Shanghai Institute of Ceramics, Chinese Academy of Science, Shanghai 201800 (China); Wang, Yongqing; Zhou, Jianer [Key Laboratory of Inorganic Membrane, Jingdezhen Ceramic Institute, Jingdezhen 333001 (China); Song, Lixin [Key Laboratory of Inorganic Coating Materials, Shanghai Institute of Ceramics, Chinese Academy of Science, Shanghai 201800 (China)

    2015-02-28

    Graphical abstract: By adding an alkaline (NaOH or KOH) solution, the unprecipitated nano graphene oxide undergoes fast aggregation from the residual strong-acid filtrate of the modified Hummers method and forms the stable floccules when the pH value of the filtrate is about 1.7. The acid–base interaction with the surface functional groups of the carbon layers plays a role in the aggregation of the unprecipitated nano graphene oxide. - Highlights: • The novel and high-efficient method for separating graphene oxide was showed. • Graphene oxide undergoes aggregation and forms the floccules when pH value is ∼1.7. • The acid–base interaction plays a role in the aggregation of graphene oxide. - Abstract: In the modified Hummers method for preparing graphene oxide, the yellow slurry can be obtained. After filtering through a quantitative filter paper, the strong-acid filtrate containing the unprecipitated nano graphene oxide was gained. The corresponding filtrate was added gradually with an alkaline (NaOH or KOH) solution at room temperature. The unprecipitated nano graphene oxide could undergo fast aggregation when the pH value of the filtrate was about 1.7 and formed the stable floccules. X-ray diffraction analysis shows the dominant peak of the floccules is about 11°, which accords to the peak of graphene oxide. Spectra of X-ray photoelectron spectroscopy confirm the presence in the floccules of an abundance of oxygen functional groups and the purified graphene oxide floccules can be obtained. Atomic force microscopy measurement shows the graphene oxide floccules consists of sheet-like objects, mostly containing only a few layers (about 5 layers). Zeta potential analysis demonstrates the surface charge of the graphene oxide is pH-sensitive and its isoelectric point is ∼1.7. The flocculation mechanism of graphene oxide ascribes to the acid–base interaction with the surface functional groups of the carbon layers.

  13. Two amino acid residues confer different binding affinities of Abelson family kinase SRC homology 2 domains for phosphorylated cortactin.

    Science.gov (United States)

    Gifford, Stacey M; Liu, Weizhi; Mader, Christopher C; Halo, Tiffany L; Machida, Kazuya; Boggon, Titus J; Koleske, Anthony J

    2014-07-11

    The closely related Abl family kinases, Arg and Abl, play important non-redundant roles in the regulation of cell morphogenesis and motility. Despite similar N-terminal sequences, Arg and Abl interact with different substrates and binding partners with varying affinities. This selectivity may be due to slight differences in amino acid sequence leading to differential interactions with target proteins. We report that the Arg Src homology (SH) 2 domain binds two specific phosphotyrosines on cortactin, a known Abl/Arg substrate, with over 10-fold higher affinity than the Abl SH2 domain. We show that this significant affinity difference is due to the substitution of arginine 161 and serine 187 in Abl to leucine 207 and threonine 233 in Arg, respectively. We constructed Abl SH2 domains with R161L and S187T mutations alone and in combination and find that these substitutions are sufficient to convert the low affinity Abl SH2 domain to a higher affinity "Arg-like" SH2 domain in binding to a phospho-cortactin peptide. We crystallized the Arg SH2 domain for structural comparison to existing crystal structures of the Abl SH2 domain. We show that these two residues are important determinants of Arg and Abl SH2 domain binding specificity. Finally, we expressed Arg containing an "Abl-like" low affinity mutant Arg SH2 domain (L207R/T233S) and find that this mutant, although properly localized to the cell periphery, does not support wild type levels of cell edge protrusion. Together, these observations indicate that these two amino acid positions confer different binding affinities and cellular functions on the distinct Abl family kinases. © 2014 by The American Society for Biochemistry and Molecular Biology, Inc.

  14. Physicochemical and in vitro antioxidant properties of pectin extracted from hot pepper (Capsicum annuum L. var. acuminatum (Fingerh.)) residues with hydrochloric and sulfuric acids.

    Science.gov (United States)

    Xu, Honggao; Tai, Kedong; Wei, Tong; Yuan, Fang; Gao, Yanxiang

    2017-11-01

    Transformation of hot pepper residues to value-added products with concomitant benefits on environmental pollution would be of great value to capsicum oleoresin manufacturers. Pectin, a soluble dietary fiber with multiple functions, from hot pepper residues was investigated in this study. The extraction of hot pepper pectin using hydrochloric acid was first optimized using response surface methodology (RSM). The most efficient parameters for maximum hot pepper pectin yield (14.63%, dry basis) were a pH of 1.0, a temperature of 90 °C, an extraction time of 2 h and a liquid-to-solid ratio of 20 L g -1 . The pectin was mainly composed of uronic acids, and the major neutral sugars were galactose and glucose. The structure of hot pepper pectin was characterized by homogalacturonan and rhamnogalacturonan I elements. The physicochemical properties of hot pepper pectin extracted by sulfuric acid and hydrochloric acid were further investigated. The content of protein and degree of esterification in hot pepper pectin extracted with sulfuric acid solution (SP) were higher (P hot pepper pectin, hot pepper residues would be a new source to obtain pectin, and SP would be more preferred than HP. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

  15. Changes in FGFR2 amino-acid residue Asn549 lead to Crouzon and Pfeiffer syndrome with hydrocephalus

    Directory of Open Access Journals (Sweden)

    Caroline Apra

    2016-10-01

    Full Text Available Mutations in Fibroblast Growth Factor Receptor II (FGFR2 have been identified in patients with Crouzon and Pfeiffer syndrome, among which rare mutations of the intracellular tyrosine kinase domain. Correlating subtle phenotypes with each rare mutation is still in progress. In Necker-Enfants Malades Hospital, we identified three patients harboring three different pathogenic variants of the same amino acid residue Asn-549 located in this domain: in addition to a very typical crouzonoid appearance, they all developed clinically relevant hydrocephalus, which is an inconstant feature of Crouzon and Pfeiffer syndrome. Overall, FGFR2 tyrosine kinase domain mutations account for 5/67 (7.4% cases in our hospital. We describe a novel mutation, p.Asn549Ser, and new cases of p.Asn549His and p.Asn549Thr mutations, each reported once before. Our three cases of Asn-549 mutations, alongside with rare previously reported cases, show that these patients are at higher risk of hydrocephalus. Clinical and imaging follow-up, with possible early surgery, may help prevent secondary intellectual disability.

  16. Three amino acid residues bind corn odorants to McinOBP1 in the polyembryonic endoparasitoid of Macrocentrus cingulum Brischke.

    Directory of Open Access Journals (Sweden)

    Tofael Ahmed

    Full Text Available Odorant binding proteins (OBPs play a central role in transporting odorant molecules from the sensillum lymph to olfactory receptors to initiate behavioral responses. In this study, the OBP of Macrocentrus cingulum McinOBP1 was expressed in Escherichia coli and purified by Ni ion affinity chromatography. Real-time PCR experiments indicate that the McinOBP1 is expressed mainly in adult antennae, with expression levels differing by sex. Ligand-binding experiments using N-phenyl-naphthylamine (1-NPN as a fluorescent probe demonstrated that the McinOBP1 can bind green-leaf volatiles, including aldehydes and terpenoids, but also can bind aliphatic alcohols with good affinity, in the order trans-2-nonenal>cis-3-hexen-1-ol>trans-caryophelle, suggesting a role of McinOBP1 in general odorant chemoreception. We chose those three odorants for further homology modeling and ligand docking based on their binding affinity. The Val58, Leu62 and Glu130 are the key amino acids in the binding pockets that bind with these three odorants. The three mutants, Val58, Leu62 and Glu130, where the valine, leucine and glutamic residues were replaced by alanine, proline and alanine, respectively; showed reduced affinity to these odorants. This information suggests, Val58, Leu62 and Glu130 are involved in the binding of these compounds, possibly through the specific recognition of ligands that forms hydrogen bonds with the ligands functional groups.

  17. Residual Tensile Property of Plain Woven Jute Fiber/Poly(Lactic Acid Green Composites during Thermal Cycling

    Directory of Open Access Journals (Sweden)

    Hideaki Katogi

    2016-07-01

    Full Text Available This study investigated the residual tensile properties of plain woven jute fiber reinforced poly(lactic acid (PLA during thermal cycling. Temperature ranges of thermal cycling tests were 35–45 °C and 35–55 °C. The maximum number of cycles was 103 cycles. The quasi-static tensile tests of jute fiber, PLA, and composite were conducted after thermal cycling tests. Thermal mechanical analyses of jute fiber and PLA were conducted after thermal cycling tests. Results led to the following conclusions. For temperatures of 35–45 °C, tensile strength of composite at 103 cycles decreased 10% compared to that of composite at 0 cycles. For temperatures of 35–55 °C, tensile strength and Young’s modulus of composite at 103 cycles decreased 15% and 10%, respectively, compared to that of composite at 0 cycles. Tensile properties and the coefficient of linear expansion of PLA and jute fiber remained almost unchanged after thermal cycling tests. From observation of a fracture surface, the length of fiber pull out in the fracture surface of composite at 103 cycles was longer than that of composite at 0 cycles. Therefore, tensile properties of the composite during thermal cycling were decreased, probably because of the decrease of interfacial adhesion between the fiber and resin.

  18. Residual Tensile Property of Plain Woven Jute Fiber/Poly(Lactic Acid) Green Composites during Thermal Cycling.

    Science.gov (United States)

    Katogi, Hideaki; Takemura, Kenichi; Akiyama, Motoki

    2016-07-14

    This study investigated the residual tensile properties of plain woven jute fiber reinforced poly(lactic acid) (PLA) during thermal cycling. Temperature ranges of thermal cycling tests were 35-45 °C and 35-55 °C. The maximum number of cycles was 10³ cycles. The quasi-static tensile tests of jute fiber, PLA, and composite were conducted after thermal cycling tests. Thermal mechanical analyses of jute fiber and PLA were conducted after thermal cycling tests. Results led to the following conclusions. For temperatures of 35-45 °C, tensile strength of composite at 10³ cycles decreased 10% compared to that of composite at 0 cycles. For temperatures of 35-55 °C, tensile strength and Young's modulus of composite at 10³ cycles decreased 15% and 10%, respectively, compared to that of composite at 0 cycles. Tensile properties and the coefficient of linear expansion of PLA and jute fiber remained almost unchanged after thermal cycling tests. From observation of a fracture surface, the length of fiber pull out in the fracture surface of composite at 10³ cycles was longer than that of composite at 0 cycles. Therefore, tensile properties of the composite during thermal cycling were decreased, probably because of the decrease of interfacial adhesion between the fiber and resin.

  19. Residual wood polymers facilitate compounding of microfibrillated cellulose with poly(lactic acid) for 3D printer filaments

    Science.gov (United States)

    Winter, Armin; Mundigler, Norbert; Holzweber, Julian; Veigel, Stefan; Müller, Ulrich; Kovalcik, Adriana; Gindl-Altmutter, Wolfgang

    2017-12-01

    Microfibrillated cellulose (MFC) is a fascinating material with an obvious potential for composite reinforcement due to its excellent mechanics together with high specific surface area. However, in order to use this potential, commercially viable solutions to important technological challenges have to be found. Notably, the distinct hydrophilicity of MFC prevents efficient drying without loss in specific surface area, necessitating storage and processing in wet condition. This greatly hinders compounding with important technical polymers immiscible with water. Differently from cellulose, the chemistry of the major wood polymers lignin and hemicellulose is much more diverse in terms of functional groups. Specifically, the aromatic moieties present in lignin and acetyl groups in hemicellulose provide distinctly less polar surface-chemical functionality compared to hydroxyl groups which dominate the surface-chemical character of cellulose. It is shown that considerable advantages in the production of MFC-filled poly(lactic acid) filaments for three-dimensional printing can be obtained through the use of MFC containing residual lignin and hemicellulose due to their advantageous surface-chemical characteristics. Specifically, considerably reduced agglomerations of MFC in the filaments in combination with improved printability and improved toughness of printed objects are achieved. This article is part of a discussion meeting issue `New horizons for cellulose nanotechnology'.

  20. Improved prediction of residue flexibility by embedding optimized amino acid grouping into RSA-based linear models.

    Science.gov (United States)

    Zhang, Hua; Kurgan, Lukasz

    2014-12-01

    Knowledge of protein flexibility is vital for deciphering the corresponding functional mechanisms. This knowledge would help, for instance, in improving computational drug design and refinement in homology-based modeling. We propose a new predictor of the residue flexibility, which is expressed by B-factors, from protein chains that use local (in the chain) predicted (or native) relative solvent accessibility (RSA) and custom-derived amino acid (AA) alphabets. Our predictor is implemented as a two-stage linear regression model that uses RSA-based space in a local sequence window in the first stage and a reduced AA pair-based space in the second stage as the inputs. This method is easy to comprehend explicit linear form in both stages. Particle swarm optimization was used to find an optimal reduced AA alphabet to simplify the input space and improve the prediction performance. The average correlation coefficients between the native and predicted B-factors measured on a large benchmark dataset are improved from 0.65 to 0.67 when using the native RSA values and from 0.55 to 0.57 when using the predicted RSA values. Blind tests that were performed on two independent datasets show consistent improvements in the average correlation coefficients by a modest value of 0.02 for both native and predicted RSA-based predictions.

  1. Residual wood polymers facilitate compounding of microfibrillated cellulose with poly(lactic acid) for 3D printer filaments.

    Science.gov (United States)

    Winter, Armin; Mundigler, Norbert; Holzweber, Julian; Veigel, Stefan; Müller, Ulrich; Kovalcik, Adriana; Gindl-Altmutter, Wolfgang

    2018-02-13

    Microfibrillated cellulose (MFC) is a fascinating material with an obvious potential for composite reinforcement due to its excellent mechanics together with high specific surface area. However, in order to use this potential, commercially viable solutions to important technological challenges have to be found. Notably, the distinct hydrophilicity of MFC prevents efficient drying without loss in specific surface area, necessitating storage and processing in wet condition. This greatly hinders compounding with important technical polymers immiscible with water. Differently from cellulose, the chemistry of the major wood polymers lignin and hemicellulose is much more diverse in terms of functional groups. Specifically, the aromatic moieties present in lignin and acetyl groups in hemicellulose provide distinctly less polar surface-chemical functionality compared to hydroxyl groups which dominate the surface-chemical character of cellulose. It is shown that considerable advantages in the production of MFC-filled poly(lactic acid) filaments for three-dimensional printing can be obtained through the use of MFC containing residual lignin and hemicellulose due to their advantageous surface-chemical characteristics. Specifically, considerably reduced agglomerations of MFC in the filaments in combination with improved printability and improved toughness of printed objects are achieved.This article is part of a discussion meeting issue 'New horizons for cellulose nanotechnology'. © 2017 The Author(s).

  2. Studies on the riboflavin, niacin, pantothenic acid and choline requirements of young bobwhite quail

    Science.gov (United States)

    Serafin, J.A.

    1974-01-01

    Four experiments were conducted to examine the riboflavin, niacin, pantothenic acid and choline requirements of young Bobwhite quail. Quail fed purified diets deficient in either riboflavin, niacin, pantothenic acid or choline grew poorly and high mortality occurred by 5 weeks of age. Under the conditions of these experiments, it was found that: (1) young quail require approximately 3.8 mg. riboflavin/kg. diet for satisfactory growth and survival; (2) no more than 31 mg. niacin/kg. diet are required for normal growth and survival of young quail; (3) the requirement for pantothenic acid is higher than has previously been reported, quail in these studies requiring 12.6 mg. pantothenic acid/kg. feed for growth and survival; and (4) the requirement for choline for reducing mortality is approximately 1000 mg./kg., while the amount necessary for normal growth of young quail is no greater than 1500 mg./kg. when the diet contains ample amounts of methionine. Quail fed a niacin-deficient diet developed stiff, shortened feathers and an erythema about the head; those receiving a riboflavin-deficient ration developed enlarged hocks and bowed legs, as did quail fed diets low or devoid of choline. Aside from slow growth, poor feathering was the only other indication that a deficient diet was being fed when quail were placed on a basal ration without pantothenic acid for five weeks.

  3. 75 FR 20785 - Polyglyceryl Phthalate Ester of Coconut Oil Fatty Acids; Exemption from the Requirement of a...

    Science.gov (United States)

    2010-04-21

    ... Phthalate Ester of Coconut Oil Fatty Acids; Exemption from the Requirement of a Tolerance; Technical... ester of coconut oil fatty acids; exemption from the requirement of a tolerance. This document is being... requirement of a tolerance for ``polyglyceryl phthalate ester of coconut oil fatty acids'' pursuant to a...

  4. The omega-3 fatty acid eicosapentaenoic acid is required for normal alcohol response behaviors in C. elegans.

    Directory of Open Access Journals (Sweden)

    Richard C Raabe

    Full Text Available Alcohol addiction is a widespread societal problem, for which there are few treatments. There are significant genetic and environmental influences on abuse liability, and understanding these factors will be important for the identification of susceptible individuals and the development of effective pharmacotherapies. In humans, the level of response to alcohol is strongly predictive of subsequent alcohol abuse. Level of response is a combination of counteracting responses to alcohol, the level of sensitivity to the drug and the degree to which tolerance develops during the drug exposure, called acute functional tolerance. We use the simple and well-characterized nervous system of Caenorhabditis elegans to model the acute behavioral effects of ethanol to identify genetic and environmental factors that influence level of response to ethanol. Given the strong molecular conservation between the neurobiological machinery of worms and humans, cellular-level effects of ethanol are likely to be conserved. Increasingly, variation in long-chain polyunsaturated fatty acid levels has been implicated in complex neurobiological phenotypes in humans, and we recently found that fatty acid levels modify ethanol responses in worms. Here, we report that 1 eicosapentaenoic acid, an omega-3 polyunsaturated fatty acid, is required for the development of acute functional tolerance, 2 dietary supplementation of eicosapentaenoic acid is sufficient for acute tolerance, and 3 dietary eicosapentaenoic acid can alter the wild-type response to ethanol. These results suggest that genetic variation influencing long-chain polyunsaturated fatty acid levels may be important abuse liability loci, and that dietary polyunsaturated fatty acids may be an important environmental modulator of the behavioral response to ethanol.

  5. The Shigella flexneri OmpA amino acid residues 188EVQ190 are essential for the interaction with the virulence factor PhoN2.

    Science.gov (United States)

    Scribano, Daniela; Damico, Rosanna; Ambrosi, Cecilia; Superti, Fabiana; Marazzato, Massimiliano; Conte, Maria Pia; Longhi, Catia; Palamara, Anna Teresa; Zagaglia, Carlo; Nicoletti, Mauro

    2016-12-01

    Shigella flexneri is an intracellular pathogen that deploys an arsenal of virulence factors promoting host cell invasion, intracellular multiplication and intra- and inter-cellular dissemination. We have previously reported that the interaction between apyrase (PhoN2), a periplasmic ATP-diphosphohydrolase, and the C-terminal domain of the outer membrane (OM) protein OmpA is likely required for proper IcsA exposition at the old bacterial pole and thus for full virulence expression of Shigella flexneri (Scribano et al., 2014). OmpA, that is the major OM protein of Gram-negative bacteria, is a multifaceted protein that plays many different roles both in the OM structural integrity and in the virulence of several pathogens. Here, by using yeast two-hybrid technology and by constructing an in silico 3D model of OmpA from S. flexneri 5a strain M90T, we observed that the OmpA residues 188 EVQ 190 are likely essential for PhoN2-OmpA interaction. The 188 EVQ 190 amino acids are located within a flexible region of the OmpA protein that could represent a scaffold for protein-protein interaction.

  6. The One-carbon Carrier Methylofuran from Methylobacterium extorquens AM1 Contains a Large Number of α- and γ-Linked Glutamic Acid Residues*

    Science.gov (United States)

    Hemmann, Jethro L.; Saurel, Olivier; Ochsner, Andrea M.; Stodden, Barbara K.; Kiefer, Patrick; Milon, Alain; Vorholt, Julia A.

    2016-01-01

    Methylobacterium extorquens AM1 uses dedicated cofactors for one-carbon unit conversion. Based on the sequence identities of enzymes and activity determinations, a methanofuran analog was proposed to be involved in formaldehyde oxidation in Alphaproteobacteria. Here, we report the structure of the cofactor, which we termed methylofuran. Using an in vitro enzyme assay and LC-MS, methylofuran was identified in cell extracts and further purified. From the exact mass and MS-MS fragmentation pattern, the structure of the cofactor was determined to consist of a polyglutamic acid side chain linked to a core structure similar to the one present in archaeal methanofuran variants. NMR analyses showed that the core structure contains a furan ring. However, instead of the tyramine moiety that is present in methanofuran cofactors, a tyrosine residue is present in methylofuran, which was further confirmed by MS through the incorporation of a 13C-labeled precursor. Methylofuran was present as a mixture of different species with varying numbers of glutamic acid residues in the side chain ranging from 12 to 24. Notably, the glutamic acid residues were not solely γ-linked, as is the case for all known methanofurans, but were identified by NMR as a mixture of α- and γ-linked amino acids. Considering the unusual peptide chain, the elucidation of the structure presented here sets the basis for further research on this cofactor, which is probably the largest cofactor known so far. PMID:26895963

  7. The One-carbon Carrier Methylofuran from Methylobacterium extorquens AM1 Contains a Large Number of α- and γ-Linked Glutamic Acid Residues.

    Science.gov (United States)

    Hemmann, Jethro L; Saurel, Olivier; Ochsner, Andrea M; Stodden, Barbara K; Kiefer, Patrick; Milon, Alain; Vorholt, Julia A

    2016-04-22

    Methylobacterium extorquens AM1 uses dedicated cofactors for one-carbon unit conversion. Based on the sequence identities of enzymes and activity determinations, a methanofuran analog was proposed to be involved in formaldehyde oxidation in Alphaproteobacteria. Here, we report the structure of the cofactor, which we termed methylofuran. Using an in vitro enzyme assay and LC-MS, methylofuran was identified in cell extracts and further purified. From the exact mass and MS-MS fragmentation pattern, the structure of the cofactor was determined to consist of a polyglutamic acid side chain linked to a core structure similar to the one present in archaeal methanofuran variants. NMR analyses showed that the core structure contains a furan ring. However, instead of the tyramine moiety that is present in methanofuran cofactors, a tyrosine residue is present in methylofuran, which was further confirmed by MS through the incorporation of a (13)C-labeled precursor. Methylofuran was present as a mixture of different species with varying numbers of glutamic acid residues in the side chain ranging from 12 to 24. Notably, the glutamic acid residues were not solely γ-linked, as is the case for all known methanofurans, but were identified by NMR as a mixture of α- and γ-linked amino acids. Considering the unusual peptide chain, the elucidation of the structure presented here sets the basis for further research on this cofactor, which is probably the largest cofactor known so far. © 2016 by The American Society for Biochemistry and Molecular Biology, Inc.

  8. Identification of functional residues essential for dehalogenation by the non-stereospecific α-haloalkanoic acid dehalogenase from Rhizobium sp. RC1.

    Science.gov (United States)

    Hamid, Azzmer Azzar Abdul; Hamid, Tengku Haziyamin Tengku Abdul; Wahab, Roswanira Abdul; Huyop, Fahrul

    2015-03-01

    The non-stereospecific α-haloalkanoic acid dehalogenase DehE from Rhizobium sp. RC1 catalyzes the removal of the halide from α-haloalkanoic acid D,L-stereoisomers and, by doing so, converts them into hydroxyalkanoic acid L,D-stereoisomers, respectively. DehE has been extensively studied to determine its potential to act as a bioremediation agent, but its structure/function relationship has not been characterized. For this study, we explored the functional relevance of several putative active-site amino acids by site-specific mutagenesis. Ten active-site residues were mutated individually, and the dehalogenase activity of each of the 10 resulting mutants in soluble cell lysates against D- and L-2-chloropropionic acid was assessed. Interestingly, the mutants W34→A,F37→A, and S188→A had diminished activity, suggesting that these residues are functionally relevant. Notably, the D189→N mutant had no activity, which strongly implies that it is a catalytically important residue. Given our data, we propose a dehalogenation mechanism for DehE, which is the same as that suggested for other non-stereospecific α-haloalkanoic acid dehalogenases. To the best of our knowledge, this is the first report detailing a functional aspect for DehE, and our results could help pave the way for the bioengineering of haloalkanoic acid dehalogenases with improved catalytic properties. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. Effect of the inclusion of fish residue oils in diets on the fatty acid profile of muscles of males and females lambari (Astyanax altiparanae

    Directory of Open Access Journals (Sweden)

    Ligia Uribe Gonçalves

    2012-09-01

    Full Text Available This study evaluated the effects of two lipids sources of fish residue (tilapia and salmon compared with a vegetable oil source (soybean oil on the fatty acid profiles of male and female lambari. This experiment was developed in a completely randomized experimental design in a 3 × 2 factorial arrangement, totaling 6 treatments resulting from the combination of the three experimental diets for both sexes, with four replications for each treatment. This study involved 120 male (2.58±0.13 g and 72 female lambari (4.00±0.09 g, fed the experimental diets twice a day until apparent satiation for a period of 60 days. Oleic, linoleic, palmitic and stearic fatty acids were found at higher concentrations in all experimental oils and diets, as well in the muscle of male and female lambari. The low amounts of arachidonic, eicosapentaenoic and docosahexaenoic acids in the experimental diets and subsequent greater concentrations in muscle tissue, suggested that lambari are able to desaturate and elongate the chain of fatty acids with 18 carbons. The fish of both sexes that received the diet with soybean oil showed high levels of n-6 fatty acids, especially of C18: 2n-6 and low levels of eicosapentaenoic and docosahexaenoic acids. The diet with salmon residue oil promoted higher levels of fatty acids of the n-3 series and resulted in the best n-3/n-6 ratio in the muscle of male and female lambari. The oils from fish residues can be a substitute for traditional fish oil and its use in the lambari diets does not impair its growth.

  10. Efficacy of citric acid denture cleanser on the Candida albicans biofilm formed on poly(methyl methacrylate): effects on residual biofilm and recolonization process.

    Science.gov (United States)

    Faot, Fernanda; Cavalcanti, Yuri Wanderley; Mendonça e Bertolini, Martinna de; Pinto, Luciana de Rezende; da Silva, Wander José; Cury, Altair Antoninha Del Bel

    2014-06-23

    It is well known that the use of denture cleansers can reduce Candida albicans biofilm accumulation; however, the efficacy of citric acid denture cleansers is uncertain. In addition, the long-term efficacy of this denture cleanser is not well established, and their effect on residual biofilms is unknown. This in vitro study evaluated the efficacy of citric acid denture cleanser treatment on C. albicans biofilm recolonization on poly(methyl methacrylate) (PMMA) surface. C. albicans biofilms were developed for 72 h on PMMA resin specimens (n = 168), which were randomly assigned to 1 of 3 cleansing treatments (CTs) overnight (8 h). CTs included purified water as a control (CTC) and two experimental groups that used either a 1:5 dilution of citric acid denture cleanser (CT5) or a 1:8 dilution of citric acid denture cleanser (CT8). Residual biofilms adhering to the specimens were collected and quantified at two time points: immediately after CTs (ICT) and after cleaning and residual biofilm recolonization (RT). Residual biofilms were analyzed by quantifying the viable cells (CFU/mL), and biofilm architecture was evaluated by confocal laser scanning microscopy (CLSM) and scanning electron microscopy (SEM). Denture cleanser treatments and evaluation periods were considered study factors. Data were analyzed using two-way ANOVA and Tukey's Honestly Significant Difference (HSD) test (α = 0.05). Immediately after treatments, citric acid denture cleansing solutions (CT5 and CT8) reduced the number of viable cells as compared with the control (p recolonization (p recolonization was also detected by CLSM and SEM analysis, which revealed a higher biomass and average biofilm thickness for the CT8 group (p recolonization.

  11. Identification of two critical amino acid residues of the severe acute respiratory syndrome coronavirus spike protein for its variation in zoonotic tropism transition via a double substitution strategy.

    Science.gov (United States)

    Qu, Xiu-Xia; Hao, Pei; Song, Xi-Jun; Jiang, Si-Ming; Liu, Yan-Xia; Wang, Pei-Gang; Rao, Xi; Song, Huai-Dong; Wang, Sheng-Yue; Zuo, Yu; Zheng, Ai-Hua; Luo, Min; Wang, Hua-Lin; Deng, Fei; Wang, Han-Zhong; Hu, Zhi-Hong; Ding, Ming-Xiao; Zhao, Guo-Ping; Deng, Hong-Kui

    2005-08-19

    Severe acute respiratory syndrome coronavirus (SARS-CoV) is a recently identified human coronavirus. The extremely high homology of the viral genomic sequences between the viruses isolated from human (huSARS-CoV) and those of palm civet origin (pcSARS-CoV) suggested possible palm civet-to-human transmission. Genetic analysis revealed that the spike (S) protein of pcSARS-CoV and huSARS-CoV was subjected to the strongest positive selection pressure during transmission, and there were six amino acid residues within the receptor-binding domain of the S protein being potentially important for SARS progression and tropism. Using the single-round infection assay, we found that a two-amino acid substitution (N479K/T487S) of a huSARS-CoV for those of pcSARS-CoV almost abolished its infection of human cells expressing the SARS-CoV receptor ACE2 but no effect upon the infection of mouse ACE2 cells. Although single substitution of these two residues had no effects on the infectivity of huSARS-CoV, these recombinant S proteins bound to human ACE2 with different levels of reduced affinity, and the two-amino acid-substituted S protein showed extremely low affinity. On the contrary, substitution of these two amino acid residues of pcSARS-CoV for those of huSRAS-CoV made pcSARS-CoV capable of infecting human ACE2-expressing cells. These results suggest that amino acid residues at position 479 and 487 of the S protein are important determinants for SARS-CoV tropism and animal-to-human transmission.

  12. Local sequence information in cellular retinoic acid-binding protein I: specific residue roles in beta-turns.

    Science.gov (United States)

    Rotondi, Kenneth S; Gierasch, Lila M

    2003-01-01

    We have recently shown that two of the beta-turns (III and IV) in the ten-stranded, beta-clam protein, cellular retinoic acid-binding protein I (CRABP I), are favored in short peptide fragments, arguing that they are encoded by local interactions (K. S. Rotondi and L. M. Gierasch, Biochemistry, 2003, Vol. 42, pp. 7976-7985). In this paper we examine these turns in greater detail to dissect the specific local interactions responsible for their observed native conformational biases. Conformations of peptides corresponding to the turn III and IV fragments were examined under conditions designed to selectively disrupt stabilizing interactions, using pH variation, chaotrope addition, or mutagenesis to probe specific side-chain influences. We find that steric constraints imposed by excluded volume effects between near neighbor residues (i,i+2), favorable polar (i,i+2) interactions, and steric permissiveness of glycines are the principal factors accounting for the observed native bias in these turns. Longer-range stabilizing interactions across the beta-turns do not appear to play a significant role in turn stability in these short peptides, in contrast to their importance in hairpins. Additionally, our data add to a growing number of examples of the 3:5 type I turn with a beta-bulge as a class of turns with high propensity to form locally defined structure. Current work is directed at the interplay between the local sequence information in the turns and more long-range influences in the mechanism of folding of this predominantly beta-sheet protein. Copyright 2004 Wiley Periodicals, Inc.

  13. The myeloperoxidase-derived oxidant hypothiocyanous acid inhibits protein tyrosine phosphatases via oxidation of key cysteine residues

    DEFF Research Database (Denmark)

    Cook, Naomi L.; Moeke, Cassidy H.; Fantoni, Luca I.

    2016-01-01

    Phosphorylation of protein tyrosine residues is critical to cellular processes, and is regulated by kinases and phosphatases (PTPs). PTPs contain a redox-sensitive active site Cys residue, which is readily oxidized. Myeloperoxidase, released from activated leukocytes, catalyzes thiocyanate ion (SCN...

  14. Stable nuclide tracer studies and human amino acid requirements. A summary

    International Nuclear Information System (INIS)

    Young, V.R.

    1994-01-01

    The nutritional requirements for proteins have been estimated for various age groups. The current status of knowledge concerning the quantitative needs for specific indispensable amino acids was reviewed and it was concluded that, except for infants, current values for pre-school children, school age children and healthy adults are based on limited experimental data and/or on results from nitrogen balance determinations which are open to serious question regarding their nutritional significance. A review of 13 C-labelled tracer studies carried out in MIT laboratories was undertaken to demonstrate the applicability of stable nuclide tracer studies for purposes of determining the amino acid requirements of humans. 5 refs

  15. Coagulation of some humic acid solutions by Moringa oleifera lam seeds: effect on chlorine requirement

    Directory of Open Access Journals (Sweden)

    L.M. Bawa

    2001-12-01

    Full Text Available Experiments were carried out to study humic acid solutions and surface waters coagulation by Moringa oleifera Lam seeds aqueous extract. High amounts of such extract (up to 10 g/L were required to clarify humic acid solutions whereas 0.5 g/L were used to remove 90% of initial turbidity of a surface water. The treatment of water with low turbidity (Moringa oleifera Lam seeds extract released a high amount of organic compounds in treated solutions leading to a high chlorine requirement.

  16. Panel-reactive antibody levels and renal transplantation rates in sensitized patients after desensitization and human leucocyte antigen amino acid residue matching.

    Science.gov (United States)

    Shang, Wenjun; Dong, Laidong; Feng, Guiwen; Wang, Yue; Pang, Xinlu; Li, Jinfeng; Liu, Lei; Zhang, Weihong

    2013-08-01

    To determine whether a new desensitization protocol (mycophenolate mofetil [MMF], plasmapheresis and antithymocyte globulin [ATG], complemented with human leucocyte antigen [HLA] amino acid residue matching) could reduce panel-reactive antibody (PRA) levels in sensitized patients, to facilitate successful renal transplantation. Patients awaiting transplantation with PRA levels >10% received treatment with MMF; those with PRA levels >30% were also treated with plasmapheresis. Patients whose PRA level was desensitization were eligible for transplantation. When a donor became available, traditional HLA matching and HLA amino acid residue matching were performed. All patients received ATG induction therapy postoperatively. Thirty-two sensitized patients were enrolled. Desensitization produced a significant decrease in PRA levels; 27 patients (84.4%) became eligible for transplantation and 26 (81.2%) subsequently underwent successful transplantation. Residue matching improved the proportion with a mismatch number of 0-1 from 7.7% to 65.4%, compared with traditional HLA matching. Postoperatively, all patients showed immediate graft function. Acute rejection occurred in three patients (11.5%) and infections in seven patients (25.9%); all were treated successfully. The combination of a desensitization protocol (MMF, plasmapheresis and ATG) and residue matching appears to be an effective strategy for sensitized patients awaiting renal transplantation.

  17. Metals in proteins: correlation between the metal-ion type, coordination number and the amino-acid residues involved in the coordination.

    Science.gov (United States)

    Dokmanić, Ivan; Sikić, Mile; Tomić, Sanja

    2008-03-01

    Metal ions are constituents of many metalloproteins, in which they have either catalytic (metalloenzymes) or structural functions. In this work, the characteristics of various metals were studied (Cu, Zn, Mg, Mn, Fe, Co, Ni, Cd and Ca in proteins with known crystal structure) as well as the specificity of their environments. The analysis was performed on two data sets: the set of protein structures in the Protein Data Bank (PDB) determined with resolution metal ion and its electron donors and the latter was used to assess the preferred coordination numbers and common combinations of amino-acid residues in the neighbourhood of each metal. Although the metal ions considered predominantly had a valence of two, their preferred coordination number and the type of amino-acid residues that participate in the coordination differed significantly from one metal ion to the next. This study concentrates on finding the specificities of a metal-ion environment, namely the distribution of coordination numbers and the amino-acid residue types that frequently take part in coordination. Furthermore, the correlation between the coordination number and the occurrence of certain amino-acid residues (quartets and triplets) in a metal-ion coordination sphere was analysed. The results obtained are of particular value for the identification and modelling of metal-binding sites in protein structures derived by homology modelling. Knowledge of the geometry and characteristics of the metal-binding sites in metalloproteins of known function can help to more closely determine the biological activity of proteins of unknown function and to aid in design of proteins with specific affinity for certain metals.

  18. Quantum-mechanical analysis of amino acid residues function in the proton transport during F0F1-ATP synthase catalytic cycle

    Science.gov (United States)

    Ivontsin, L. A.; Mashkovtseva, E. V.; Nartsissov, Ya R.

    2017-11-01

    Implications of quantum-mechanical approach to the description of proton transport in biological systems are a tempting subject for an overlapping of fundamental physics and biology. The model of proton transport through the integrated membrane enzyme FoF1-ATP synthase responsible for ATP synthesis was developed. The estimation of the mathematical expectation of the proton transfer time through the half-channel was performed. Observed set of proton pathways through the inlet half-channel showed the nanosecond timescale highly dependable of some amino acid residues. There were proposed two types of crucial amino acids: critically localized (His245) and being a part of energy conserving system (Asp119).

  19. Mechanisms of mono- and poly-ubiquitination: Ubiquitination specificity depends on compatibility between the E2 catalytic core and amino acid residues proximal to the lysine

    Directory of Open Access Journals (Sweden)

    Sadowski Martin

    2010-08-01

    Full Text Available Abstract Ubiquitination involves the attachment of ubiquitin to lysine residues on substrate proteins or itself, which can result in protein monoubiquitination or polyubiquitination. Ubiquitin attachment to different lysine residues can generate diverse substrate-ubiquitin structures, targeting proteins to different fates. The mechanisms of lysine selection are not well understood. Ubiquitination by the largest group of E3 ligases, the RING-family E3 s, is catalyzed through co-operation between the non-catalytic ubiquitin-ligase (E3 and the ubiquitin-conjugating enzyme (E2, where the RING E3 binds the substrate and the E2 catalyzes ubiquitin transfer. Previous studies suggest that ubiquitination sites are selected by E3-mediated positioning of the lysine toward the E2 active site. Ultimately, at a catalytic level, ubiquitination of lysine residues within the substrate or ubiquitin occurs by nucleophilic attack of the lysine residue on the thioester bond linking the E2 catalytic cysteine to ubiquitin. One of the best studied RING E3/E2 complexes is the Skp1/Cul1/F box protein complex, SCFCdc4, and its cognate E2, Cdc34, which target the CDK inhibitor Sic1 for K48-linked polyubiquitination, leading to its proteasomal degradation. Our recent studies of this model system demonstrated that residues surrounding Sic1 lysines or lysine 48 in ubiquitin are critical for ubiquitination. This sequence-dependence is linked to evolutionarily conserved key residues in the catalytic region of Cdc34 and can determine if Sic1 is mono- or poly-ubiquitinated. Our studies indicate that amino acid determinants in the Cdc34 catalytic region and their compatibility to those surrounding acceptor lysine residues play important roles in lysine selection. This may represent a general mechanism in directing the mode of ubiquitination in E2 s.

  20. Exploration of a mechanism for the production of highly unsaturated fatty acids in Scenedesmus sp. at low temperature grown on oil crop residue based medium.

    Science.gov (United States)

    Lu, Qian; Li, Jun; Wang, Jinghan; Li, Kun; Li, Jingjing; Han, Pei; Chen, Paul; Zhou, Wenguang

    2017-11-01

    The ability of algae to produce lipids comprising of unsaturated fatty acids varies with strains and culture conditions. This study investigates the effect of temperature on the production of unsaturated fatty acids in Scenedesmus sp. grown on oil crop residue based medium. At low temperature (10°C), synthesis of lipids compromising of high contents of unsaturated fatty acids took place primarily in the early stage while protein accumulation mainly occurred in the late stage. This stepwise lipid-protein synthesis process was found to be associated with the contents of acetyl-CoA and α-KG in the algal cells. A mechanism was proposed and tested through simulation experiments which quantified the carbon flux allocation in algal cells at different cultivation stages. It is concluded that low culture temperature such as 10°C is suitable for the production of lipids comprising of unsaturated fatty acids. Copyright © 2017 Elsevier Ltd. All rights reserved.

  1. Evaluation of ozonation technique for pesticide residue removal and its effect on ascorbic acid, cyanidin-3-glucoside, and polyphenols in apple (Malus domesticus) fruits.

    Science.gov (United States)

    Swami, Saurabh; Muzammil, Raunaq; Saha, Supradip; Shabeer, Ahammed; Oulkar, Dasharath; Banerjee, Kaushik; Singh, Shashi Bala

    2016-05-01

    Ozonated water dip technique was evaluated for the detoxification of six pesticides, i.e., chlorpyrifos, cypermethrin, azoxystrobin, hexaconazole, methyl parathion, and chlorothalonil from apple fruits. Results revealed that ozonation was better than washing alone. Ozonation for 15 min decreased residues of the test pesticides in the range of from 26.91 to 73.58%, while ozonation for 30 min could remove the pesticide residues by 39.39-95.14 % compared to 19.05-72.80 % by washing. Cypermethrin was the least removed pesticide by washing as well as by ozonation. Chlorothalonil, chlorpyrifos, and azoxystrobin were removed up to 71.45-95.14 % in a 30-min ozonation period. In case of methyl parathion removal, no extra advantage could be obtained by ozonation. The HPLC analysis indicated that ozonation also affected adversely the ascorbic acid and cyanidin-3-glucoside content of apples. However, 11 polyphenols studied showed a mixed trend. Gallic acid, 3,4-dihydroxybenzoic acid, catechin, epicatechin, p-coumaric acid, quercetin-3-O-glucoside, quercetin, and kaempferol were found to decrease while syringic acid, rutin, and resveratrol were found to increase in 30-min ozonation.

  2. Simultaneous determination of difenoconazole, trifloxystrobin and its metabolite trifloxystrobin acid residues in watermelon under field conditions by GC-MS/MS.

    Science.gov (United States)

    Kang, Di; Zhang, Haizhen; Chen, Yuling; Wang, Fei; Shi, Lihong; Hu, Deyu; Zhang, Kankan

    2017-11-01

    An optimized quick, easy, cheap, effective, rugged and safe method for the simultaneous determination of difenoconazole, trifloxystrobin and its metabolite trifloxystrobin acid residues in watermelon and soil was developed and validated by gas chromatography with tandem mass spectrometry. The samples were extracted with acetonitrile (1% formic acid) and cleaned up by dispersive solid-phase extraction with octadecylsilane sorbent. The limit of quantification of the method was 0.01 mg/kg, and the limit of detection was 0.003 mg/kg for all three analytes. The recoveries of the fungicides in watermelon, pulp and soil were 72.32-99.20% for difenoconazole, 74.68-87.72% for trifloxystrobin and 78.59-92.66% for trifloxystrobin acid with relative standard deviations of 1.34-14.04%. The dissipation dynamics of difenoconazole and trifloxystrobin in watermelon and soil followed the first-order kinetics with half-lives of 3.2-8.8 days in both locations. The final residue levels of difenoconazole and trifloxystrobin were below 0.1 mg/kg (maximum residue level [MRL] set by China) and 0.2 mg/kg (MRL set by European Union), respectively, in pulp samples collected 14 days after the last application. These results could help Chinese authorities to establish MRL of trifloxystrobin in watermelon and provide guidance for the safe and proper application of both fungicides on watermelon. Copyright © 2017 John Wiley & Sons, Ltd.

  3. Strains of Lactococcus lactis with a partial pyrimidine requirement show sensitivity toward aspartic acid

    DEFF Research Database (Denmark)

    Wadskov-Hansen, Steen Lyders Lerche; Martinussen, Jan

    2009-01-01

    The growth rate of the widely used laboratory strain Lactococcus lactis subsp. cremoris LM0230 was reduced if aspartic acid were present in the growth medium. The strain LM0230 is a plasmid- and phage-cured derivative of L. lactis subsp. cremoris C2, the ancestor of the original dairy isolate L...... with the wild-type strain, and this varied with the concentration of aspartic acid. The observed effect of aspartate could be explained by the accumulation of the toxic pyrimidine de novo pathway intermediate, carbamoyl aspartate. Assays of the pyrimidine biosynthetic enzymes of L. lactis LM0230 showed...... that the partial pyrimidine requirement can be explained by a low specific activity of the pyrimidine biosynthetic enzymes. In conclusion, L. lactis LM0230 during the process of plasmid- and prophage-curing has acquired a partial pyrimidine requirement resulting in sensitivity toward aspartic acid....

  4. Casein kinase 1-Like 3 is required for abscisic acid regulation of ...

    African Journals Online (AJOL)

    Casein kinase 1-Like 3 is required for abscisic acid regulation of seed germination, root growth, and gene expression in Arabidopsis. M Wang, D Yu, X Guo, X Li, J Zhang, L Zhao, H Chang, S Hu, C Zhang, J Shi, X Liu ...

  5. Gibberellin requirement for Arabidopsis seed germination is determined both by testa characteristics and embryonic abscisic acid

    NARCIS (Netherlands)

    Debeaujon, I.; Koornneef, M.

    2000-01-01

    The mechanisms imposing a gibberellin (GA) requirement to promote the germination of dormant and non-dormant Arabidopsis seeds were analyzed using the GA-deficient mutant ga1, several seed coat pigmentation and structure mutants, and the abscisic acid (ABA)-deficient mutant aba1. Testa mutants,

  6. Structural Requirements of Alkylglyceryl-l-Ascorbic Acid Derivatives for Melanogenesis Inhibitory Activity.

    Science.gov (United States)

    Taira, Norihisa; Katsuyama, Yushi; Yoshioka, Masato; Muraoka, Osamu; Morikawa, Toshio

    2018-04-10

    l-Ascorbic acid has multifunctional benefits on skin aesthetics, including inhibition of melanin production, and is widely used in cosmetics. It, however, has low stability and poor skin penetration. We hypothesize that alkylglyceryl-l-ascorbic acid derivatives, highly stable vitamin C-alkylglycerol conjugates, would have similar anti-melanogenic activity with better stability and penetration. We test 28 alkylglyceryl-l-ascorbic acid derivatives ( 1 - 28 ) on theophylline-stimulated B16 melanoma 4A5 cells to determine if they inhibit melanogenesis and establish any structure-function relationships. Although not the most potent inhibitors, 3- O -(2,3-dihydroxypropyl)-2- O -hexyl-l-ascorbic acid ( 6 , IC 50 = 81.4 µM) and 2- O -(2,3-dihydroxypropyl)-3- O -hexyl-l-ascorbic acid ( 20 , IC 50 = 117 µM) are deemed the best candidate derivatives based on their inhibitory activities and low toxicities. These derivatives are also found to be more stable than l-ascorbic acid and to have favorable characteristics for skin penetration. The following structural requirements for inhibitory activity of alkylglyceryl-l-ascorbic acid derivatives are also determined: (i) alkylation of glyceryl-l-ascorbic acid is essential for inhibitory activity; (ii) the 3- O -alkyl-derivatives ( 2 - 14 ) exhibit stronger inhibitory activity than the corresponding 2- O -alkyl-derivatives ( 16 - 28 ); and (iii) derivatives with longer alkyl chains have stronger inhibitory activities. Mechanistically, our studies suggest that l-ascorbic acid derivatives exert their effects by suppressing the mRNA expression of tyrosinase and tyrosine-related protein-1.

  7. 37 CFR 1.823 - Requirements for nucleotide and/or amino acid sequences as part of the application.

    Science.gov (United States)

    2010-07-01

    ... may not include material other than part of the sequence listing. A fixed-width font should be used... integer expressing the number of bases or amino acid residues M. Type Whether presented sequence molecule is DNA, RNA, or PRT (protein). If a nucleotide sequence contains both DNA and RNA fragments, the type...

  8. Impact of arterial occlusion during partial nephrectomy on residual renal function. An evaluation with {sup 99m}technetium-dimercaptosuccinic acid scintigraphy

    Energy Technology Data Exchange (ETDEWEB)

    Kondo, Tsunenori; Nakazawa, Hayakazu; Ito, Fumio; Onitsuka, Shiro; Ryoji, Osamu; Yago, Rie; Hashimoto, Yasunobu; Toma, Hiroshi [Tokyo Women' s Medical Coll. (Japan)

    2002-08-01

    Partial nephrectomy (PNx) has been performed with temporary renal arterial occlusion and in situ renal hypothermia (conventional PNx). However, the impact of temporary renal arterial occlusion on residual renal function has not been well assessed. To address this question, we performed renal scintigraphy with {sup 99m}technetium-dimercaptosuccinic acid (DMSA) for the quantitative measurement of postoperative residual renal function after conventional PNx and partial nephrectomy without arterial occlusion (non-clamping PNx). Thirty-four patients underwent postoperative DMSA scintigraphy after PNx for renal cell carcinoma. No obvious difference in preoperative renal function between the diseased kidney and the contralateral kidney was found in any of the patients. Of these patients, 24 underwent conventional PNx, and 10 underwent non-clamping PNx. Residual renal function was evaluated using the relative DMSA uptake of the operated kidney. The relative DMSA uptake of the operated kidney was 39.9{+-}7.3% (25.1-58.8) after conventional PNx compared to 34.8{+-}8.9% (13.5-45.5) after non-clamping PNx. This difference was not statistically significant (P=0.15). Total ischemic time during conventional PNx had no adverse influence on the residual renal function. In the analysis of the other determinant factors influencing residual renal function, tumor size was the only significant factor that inversely correlated with the relative DMSA uptake. Our results showed that arterial clamping during PNx has no negative impact on the functional residual capacity as long as in situ renal hypothermia is adequately performed. (author)

  9. Activation of the LRR Receptor-Like Kinase PSY1R Requires Transphosphorylation of Residues in the Activation Loop

    Directory of Open Access Journals (Sweden)

    Christian B. Oehlenschlæger

    2017-11-01

    Full Text Available PSY1R is a leucine-rich repeat (LRR receptor-like kinase (RLK previously shown to act as receptor for the plant peptide hormone PSY1 (peptide containing sulfated tyrosine 1 and to regulate cell expansion. PSY1R phosphorylates and thereby regulates the activity of plasma membrane-localized H+-ATPases. While this mechanism has been studied in detail, little is known about how PSY1R itself is activated. Here we studied the activation mechanism of PSY1R. We show that full-length PSY1R interacts with members of the SERK co-receptor family in planta. We identified seven in vitro autophosphorylation sites on serine and threonine residues within the kinase domain of PSY1R using mass spectrometry. We furthermore show that PSY1R autophosphorylation occurs in trans and that the initial transphosphorylation takes place within the activation loop at residues Ser951, Thr959, and Thr963. While Thr959 and Thr963 are conserved among other related plant LRR RLKs, Ser951 is unique to PSY1R. Based on homology modeling we propose that phosphorylation of Ser951 stabilize the inactive conformation of PSY1R.

  10. Amino acid substrates impose polyamine, eIF5A, or hypusine requirement for peptide synthesis.

    Science.gov (United States)

    Shin, Byung-Sik; Katoh, Takayuki; Gutierrez, Erik; Kim, Joo-Ran; Suga, Hiroaki; Dever, Thomas E

    2017-08-21

    Whereas ribosomes efficiently catalyze peptide bond synthesis by most amino acids, the imino acid proline is a poor substrate for protein synthesis. Previous studies have shown that the translation factor eIF5A and its bacterial ortholog EF-P bind in the E site of the ribosome where they contact the peptidyl-tRNA in the P site and play a critical role in promoting the synthesis of polyproline peptides. Using misacylated Pro-tRNAPhe and Phe-tRNAPro, we show that the imino acid proline and not tRNAPro imposes the primary eIF5A requirement for polyproline synthesis. Though most proline analogs require eIF5A for efficient peptide synthesis, azetidine-2-caboxylic acid, a more flexible four-membered ring derivative of proline, shows relaxed eIF5A dependency, indicating that the structural rigidity of proline might contribute to the requirement for eIF5A. Finally, we examine the interplay between eIF5A and polyamines in promoting translation elongation. We show that eIF5A can obviate the polyamine requirement for general translation elongation, and that this activity is independent of the conserved hypusine modification on eIF5A. Thus, we propose that the body of eIF5A functionally substitutes for polyamines to promote general protein synthesis and that the hypusine modification on eIF5A is critically important for poor substrates like proline. Published by Oxford University Press on behalf of Nucleic Acids Research 2017.

  11. RBscore&NBench: a high-level web server for nucleic acid binding residues prediction with a large-scale benchmarking database.

    Science.gov (United States)

    Miao, Zhichao; Westhof, Eric

    2016-07-08

    RBscore&NBench combines a web server, RBscore and a database, NBench. RBscore predicts RNA-/DNA-binding residues in proteins and visualizes the prediction scores and features on protein structures. The scoring scheme of RBscore directly links feature values to nucleic acid binding probabilities and illustrates the nucleic acid binding energy funnel on the protein surface. To avoid dataset, binding site definition and assessment metric biases, we compared RBscore with 18 web servers and 3 stand-alone programs on 41 datasets, which demonstrated the high and stable accuracy of RBscore. A comprehensive comparison led us to develop a benchmark database named NBench. The web server is available on: http://ahsoka.u-strasbg.fr/rbscorenbench/. © The Author(s) 2016. Published by Oxford University Press on behalf of Nucleic Acids Research.

  12. Application of Ganghwa Mugwort in Combination with Ascorbic Acid for the Reduction of Residual Nitrite in Pork Sausage during Refrigerated Storage

    Science.gov (United States)

    Hwang, Ko-Eun; Kim, Hyun-Wook; Song, Dong-Heon; Kim, Yong-Jae; Ham, Youn-Kyung; Lee, Choong-Hee; Choi, Yun-Sang; Kim, Cheon-Jei

    2014-01-01

    The application of ganghwa mugwort (GM), ascorbic acid (AC), and their combinations for reduction of residual nitrite contents was analyzed in pork sausages during storage of 28 d. Six treatments of pork sausages contained the following: Control (no antioxidant added), AC (0.05% AC), GM 0.1 (0.1% GM), GM 0.2 (0.2% GM), AC+GM 0.1 (0.05% AC + 0.1% GM) and AC+GM 0.2 (0.05% AC + 0.2% GM). Results showed that the mixture of 0.05% AC and 0.2% GM was most effective for reducing thiobarbituric acid reactive substances (TBARS) and residual nitrite contents than the control and GM added sausages alone (pcolor values of all treatments were significantly affected by adding GM (either alone or with AC). Additionally, the total color difference (ΔE) and hue angle (H°) values of treatments added with GM were higher than those of the control as the amount of GM increased (p0.05). Our results showed possible applications of antioxidant combination, for preventing the lipid oxidation and decreasing the residual nitrite levels of meat products. PMID:26760936

  13. Conversion of agroindustrial residues for high poly(γ-glutamic acid) production by Bacillus subtilis NX-2 via solid-state fermentation.

    Science.gov (United States)

    Tang, Bao; Xu, Hong; Xu, Zongqi; Xu, Cen; Xu, Zheng; Lei, Peng; Qiu, Yibin; Liang, Jinfeng; Feng, Xiaohai

    2015-04-01

    Poly(γ-glutamic acid) (γ-PGA) production by Bacillus subtilis NX-2 was carried out through solid-state fermentation with dry mushroom residues (DMR) and monosodium glutamate production residues (MGPR; a substitute of glutamate) for the first time. Dry shiitake mushroom residue (DSMR) was found to be the most suitable solid substrate among these DMRs; the optimal DSMR-to-MGPR ratio was optimized as 12:8. To increase γ-PGA production, industrial waste glycerol was added as a carbon source supplement to the solid-state medium. As a result, γ-PGA production increased by 34.8%. The batch fermentation obtained an outcome of 115.6 g kg(-1) γ-PGA and 39.5×10(8) colony forming units g(-1) cells. Furthermore, a satisfactory yield of 107.7 g kg(-1) γ-PGA was achieved by compost experiment on a scale of 50 kg in open air, indicating that economically large-scale γ-PGA production was feasible. Therefore, this study provided a novel method to produce γ-PGA from abundant and low-cost agroindustrial residues. Copyright © 2015 Elsevier Ltd. All rights reserved.

  14. Metabolism and Residues of 2,4-Dichlorophenoxyacetic Acid in DAS-40278-9 Maize (Zea mays) Transformed with Aryloxyalkanoate Dioxygenase-1 Gene.

    Science.gov (United States)

    Zhou, Xiao; Rotondaro, Sandra L; Ma, Mingming; Rosser, Steve W; Olberding, Ed L; Wendelburg, Brian M; Adelfinskaya, Yelena A; Balcer, Jesse L; Blewett, T Craig; Clements, Bruce

    2016-10-12

    DAS-40278-9 maize, which is developed by Dow AgroSciences, has been genetically modified to express the aryloxyalkanoate dioxygenase-1 (AAD-1) protein and is tolerant to phenoxy auxin herbicides, such as 2,4-dichlorophenoxyacetic acid (2,4-D). To understand the metabolic route and residue distribution of 2,4-D in DAS-40278-9 maize, a metabolism study was conducted with 14 C-radiolabeled 2,4-D applied at the maximum seasonal rate. Plants were grown in boxes outdoors. Forage and mature grain, cobs, and stover were collected for analysis. The metabolism study showed that 2,4-D was metabolized to 2,4-dichlorophenol (2,4-DCP), which was then rapidly conjugated with glucose. Field-scale residue studies with 2,4-D applied at the maximum seasonal rate were conducted at 25 sites in the U.S. and Canada to measure the residues of 2,4-D and free and conjugated 2,4-DCP in mature forage, grain, and stover. Residues of 2,4-D were not detectable in the majority of the grain samples and averaged <1.0 and <1.5 μg/g in forage and stover, respectively. Free plus conjugated 2,4-DCP was not observed in grain and averaged <1.0 μg/g in forage and stover.

  15. Guillain-Barre Syndrome – rehabilitation outcome, residual deficits and requirement of lower limb orthosis for locomotion at 1 year follow-up.

    Science.gov (United States)

    Gupta, Anupam; Taly, Arun B; Srivastava, Abhishek; Murali, Thyloth

    2010-01-01

    To analyse long-term functional recovery, deficits and requirement of lower limb orthosis (LLO) for locomotion in patients with Guillain-Barre Syndrome (GBS). Prospective longitudinal follow-up study. Neurological Rehabilitation unit of university hospital. Sixty-nine patients of GBS admitted for inpatient rehabilitation. Thirty-five patients (M:F, 19:16) reporting after 1 year follow-up (50.72%) were included in study (between September 2005 and July 2009). Their residual deficits and requirement of LLO were recorded and analysed. Age ranged from 4 to 65 year (29.74 ± 15.75). Twenty-seven patients had typical GBS and eight patients had acute motor axonal neuropathy variant. Twenty-eight patients (80%) had neuropathic pain needing medication with 11 required more than one drug. Twenty-one patients (60%) had foot drop and advised ankle-foot orthosis-AFO (20 bilateral AFO). Thirty patients (85.71%) needed assistive devices also for locomotion at discharge. After 1 year, foot drop was still present in 12 patients (34.28%) using orthosis. Modified Barthel Index scores, Modified Rankin Scale and Hughes Disability Scale were used to assess functional disabilities. Significant recovery was observed at the time of discharge and after 1 year (p < 0.001 each). Patients with GBS continue to show significant functional recovery for long period. They have residual deficits even after 1 year with requirement of orthosis in large number of patients.

  16. Fatty acid oxidation is required for active and quiescent brown adipose tissue maintenance and thermogenic programing

    Directory of Open Access Journals (Sweden)

    Elsie Gonzalez-Hurtado

    2018-01-01

    Full Text Available Objective: To determine the role of fatty acid oxidation on the cellular, molecular, and physiologic response of brown adipose tissue to disparate paradigms of chronic thermogenic stimulation. Methods: Mice with an adipose-specific loss of Carnitine Palmitoyltransferase 2 (Cpt2A−/−, that lack mitochondrial long chain fatty acid β-oxidation, were subjected to environmental and pharmacologic interventions known to promote thermogenic programming in adipose tissue. Results: Chronic administration of β3-adrenergic (CL-316243 or thyroid hormone (GC-1 agonists induced a loss of BAT morphology and UCP1 expression in Cpt2A−/− mice. Fatty acid oxidation was also required for the browning of white adipose tissue (WAT and the induction of UCP1 in WAT. In contrast, chronic cold (15 °C stimulation induced UCP1 and thermogenic programming in both control and Cpt2A−/− adipose tissue albeit to a lesser extent in Cpt2A−/− mice. However, thermoneutral housing also induced the loss of UCP1 and BAT morphology in Cpt2A−/− mice. Therefore, adipose fatty acid oxidation is required for both the acute agonist-induced activation of BAT and the maintenance of quiescent BAT. Consistent with this data, Cpt2A−/− BAT exhibited increased macrophage infiltration, inflammation and fibrosis irrespective of BAT activation. Finally, obese Cpt2A−/− mice housed at thermoneutrality exhibited a loss of interscapular BAT and were refractory to β3-adrenergic-induced energy expenditure and weight loss. Conclusion: Mitochondrial long chain fatty acid β-oxidation is critical for the maintenance of the brown adipocyte phenotype both during times of activation and quiescence. Keywords: Fatty acid oxidation, Brown adipose tissue, Cold induced thermogenesis, Adrenergic signaling, Adipose macrophage

  17. Spectrofluorometric and Molecular Modeling Studies on Binding of Nitrite Ion with Bovine Hemoglobin: Effect of Nitrite Ion on Amino Acid Residues

    Science.gov (United States)

    Madrakian, T.; Bagheri, H.; Afkhami, A.

    2015-05-01

    The interaction between nitrite ion and bovine hemoglobin was investigated by a spectrofluorometric technique. The experimental results indicated that the interaction causes a static quenching of the fluorescence of bovine hemoglobin, that the binding reaction is spontaneous, and that H-bonding interactions play a major role in binding of this ion to bovine hemoglobin. The formation constant for this interaction was calculated. Based on Förster's theory of nonradiative energy transfer, the binding distance between this ion and bovine hemoglobin was determined. Furthermore, the interaction of nitrite ion with tyrosine and tryptophan was investigated with synchronous fluorescence. There was no significant shift of the maximum emission wavelength with interactions of the mentioned ion with bovine hemoglobin, which implies that interaction of nitrite ion with bovine hemoglobin does not affect the microenvironment around the tryptophan and tyrosine residues. Furthermore, the effect of nitrite ion on amino acid residues of bovine hemoglobin was studied by a molecular docking technique.

  18. Identification of amino acid residues in the ligand-binding domain of the aryl hydrocarbon receptor causing the species-specific response to omeprazole: possible determinants for binding putative endogenous ligands.

    Science.gov (United States)

    Shiizaki, Kazuhiro; Ohsako, Seiichiroh; Kawanishi, Masanobu; Yagi, Takashi

    2014-02-01

    Omeprazole (OME) induces the expression of genes encoding drug-metabolizing enzymes, such as CYP1A1, via activation of the aryl hydrocarbon receptor (AhR) both in vivo and in vitro. However, the precise mechanism of OME-mediated AhR activation is still under investigation. While elucidating species-specific susceptibility to dioxin, we found that OME-mediated AhR activation was mammalian species specific. Moreover, we previously reported that OME has inhibitory activity toward CYP1A1 enzymes. From these observations, we speculated that OME-mediated AhR target gene transcription is due to AhR activation by increasing amounts of putative AhR ligands in serum by inhibition of CYP1A1 activity. We compared the amino acid sequences of OME-sensitive rabbit AhR and nonsensitive mouse AhR to identify the residues responsible for the species-specific response. Chimeric AhRs were constructed by exchanging domains between mouse and rabbit AhRs to define the region required for the response to OME. OME-mediated transactivation was observed only with the chimeric AhR that included the ligand-binding domain (LBD) of the rabbit AhR. Site-directed mutagenesis revealed three amino acids (M328, T353, and F367) in the rabbit AhR that were responsible for OME-mediated transactivation. Replacing these residues with those of the mouse AhR abolished the response of the rabbit AhR. In contrast, substitutions of these amino acids with those of the rabbit AhR altered nonsensitive mouse AhR to become sensitive to OME. These results suggest that OME-mediated AhR activation requires a specific structure within LBD that is probably essential for binding with enigmatic endogenous ligands.

  19. Identification of tocopherols, tocotrienols, and their fatty acid esters in residues and distillates of structured lipids purified by short-path distillation.

    Science.gov (United States)

    Zou, Long; Akoh, Casimir C

    2013-01-09

    The fate of endogenous vitamin E isomers during production and purification of structured lipids (SLs) was investigated. Two SLs involving tripalmitin, stearidonic acid soybean oil, and docosahexaenoic acid were synthesized by transesterification catalyzed by Novozym 435 (NSL) and acidolysis by Lipozyme TL IM (LDHA) and purified by short-path distillation (SPD). The electron impact and chemical ionization mass spectra of tocopheryl and tocotrienyl fatty acid esters in the distillates measured by GC-MS in synchronous scan/SIM mode demonstrated that these esters were formed during acidolysis as well as transesterification. The predominant esters were tocopheryl palmitate, tocopheryl oleate, and tocopheryl linoleate homologues, and no tocopheryl or tocotrienyl linolenate, stearidonate, or docosahexaenoate was found. Meanwhile, none of these esters were detected in the residues for either NSL or LDHA. Less than 50% of vitamin E isomers were present in residues after SPD. This loss played a major role in the rapid oxidative deterioration of SLs from previous studies with less contribution from the formation of tocopheryl and tocotrienyl esters. The lost tocopherols and tocotrienols present at high concentration in the distillates may be recovered and used to improve the oxidative stability of SLs.

  20. Current issues in determining dietary protein and amino-acid requirements

    DEFF Research Database (Denmark)

    Pencharz, P; Jahoor, F; Kurpad, A

    2014-01-01

    Pregnancy and the first two years of life are periods of rapid growth and yet the knowledge of requirements for protein and dietary indispensable amino acids is very limited. The development of carbon oxidation methods opens the way to studies that should fill these important gaps in knowledge.Eu.......European Journal of Clinical Nutrition advance online publication, 15 January 2014; doi:10.1038/ejcn.2013.297....

  1. Studies on the protein and sulfur amino acid requirements of young bobwhite quail

    Science.gov (United States)

    Serafin, J.A.

    1977-01-01

    Four experiments were conducted with purified diets to examine the influence of protein level and to estimate the sulfur amino acid (S.A.A.) requirement of young Bobwhite quail (Colinus virginianus). These studies demonstrated (I) that 26% protein was sufficient for rapid growth when the diet was supplemented with methionine; (2) that diets containing higher levels of protein (29.3% and 31.3%) failed to support satisfactory growth unless they contained supplemental methionine; and (3) that young Bobwhite quail require no more than 1.0% sulfur-containing amino acids for optimal growth and efficiency of feed utilization. A fifth experiment was conducted to examine the protein and S.A.A. requirements of young Bobwhite quail using practical rations and to compare results with those obtained with purified diets. Diets containing 24%, 26% and 28% protein were supplied with and without supplemental methionine in a five week study. Results showed significant growth responses to protein and supplemental methionine. Responses showed that Bobwhite quail require no more than 26% protein for maximum growth and efficiency of feed utilization when the S.A.A. level of the diet was approximately 1.0%. The results were in close agreement with those obtained with purified diets. These findings define more precisely than had been known the quantitative requirements of young Bobwhite quail for protein and for the S.A.A. necessary for optimal growth.

  2. Identification and modulation of the key amino acid residue responsible for the pH sensitivity of neoculin, a taste-modifying protein.

    Directory of Open Access Journals (Sweden)

    Ken-ichiro Nakajima

    Full Text Available Neoculin occurring in the tropical fruit of Curculigo latifolia is currently the only protein that possesses both a sweet taste and a taste-modifying activity of converting sourness into sweetness. Structurally, this protein is a heterodimer consisting of a neoculin acidic subunit (NAS and a neoculin basic subunit (NBS. Recently, we found that a neoculin variant in which all five histidine residues are replaced with alanine elicits intense sweetness at both neutral and acidic pH but has no taste-modifying activity. To identify the critical histidine residue(s responsible for this activity, we produced a series of His-to-Ala neoculin variants and evaluated their sweetness levels using cell-based calcium imaging and a human sensory test. Our results suggest that NBS His11 functions as a primary pH sensor for neoculin to elicit taste modification. Neoculin variants with substitutions other than His-to-Ala were further analyzed to clarify the role of the NBS position 11 in the taste-modifying activity. We found that the aromatic character of the amino acid side chain is necessary to elicit the pH-dependent sweetness. Interestingly, since the His-to-Tyr variant is a novel taste-modifying protein with alternative pH sensitivity, the position 11 in NBS can be critical to modulate the pH-dependent activity of neoculin. These findings are important for understanding the pH-sensitive functional changes in proteinaceous ligands in general and the interaction of taste receptor-taste substance in particular.

  3. Role of four conserved aspartic acid residues of EF-loops in the metal ion binding and in the self-assembly of ciliate Euplotes octocarinatus centrin.

    Science.gov (United States)

    Liu, Wen; Duan, Lian; Sun, Tijian; Yang, Binsheng

    2016-12-01

    Ciliate Euplotes octocarinatus centrin (EoCen) is an EF-hand calcium-binding protein closely related to the prototypical calcium sensor protein calmodulin. Four mutants (D37K, D73K, D110K and D146K) were created firstly to elucidate the importance of the first aspartic acid residues (Asp37, Asp73, Asp110 and Asp146) in the beginning of the four EF-loops of EoCen. Aromatic-sensitized Tb 3+ fluorescence indicates that the aspartic acid residues are very important for the metal-binding of EoCen, except for Asp73 (in EF-loop II). Resonance light scattering (RLS) measurements for different metal ions (Ca 2+ and Tb 3+ ) binding proteins suggest that the order of four conserved aspartic acid residues for contributing to the self-assembly of EoCen is Asp37 > Asp146 > Asp110 > Asp73. Cross-linking experiment also exhibits that Asp37 and Asp146 play critical role in the self-assembly of EoCen. Asp37, in site I, which is located in the N-terminal domain, plays the most important role in the metal ion-dependent self-assembly of EoCen, and there is cooperativity between N-terminal and C-terminal domain (especially the site IV). In addition, the dependence of Tb 3+ induced self-assembly of EoCen and the mutants on various factors, including ionic strength and pH, were characterized using RLS. Finally, 2-p-toluidinylnaphthalene-6-sulfonate (TNS) binding, ionic strength and pH control experiments indicate that in the process of EoCen self-assembly, molecular interactions are mediated by both electrostatic and hydrophobic forces, and the hydrophobic interaction has the important status.

  4. A single arginine residue is required for the interaction of the electron transferring flavoprotein (ETF) with three of its dehydrogenase partners.

    Science.gov (United States)

    Parker, Antony R

    2003-12-01

    The interaction of several dehydrogenases with the electron transferring flavoprotein (ETF) is a crucial step required for the successful transfer of electrons into the electron transport chain. The exact determinants regarding the interaction of ETF with its dehydrogenase partners are still unknown. Chemical modification of ETF with arginine-specific reagents resulted in the loss, to varying degrees, of activity with medium chain acyl-coenzyme A dehydrogenase (MCAD). The kinetic profiles showed the inactivations followed pseudo-first-order kinetics for all reagents used. For activity with MCAD, maximum inactivation of ETF was accomplished by 2,3-butanedione (4% residual activity after 120 min) and it was shown that modification of one arginine residue was responsible for the inactivation. Almost 100% restoration of this ETF activity was achieved upon incubation with free arginine. However, the same 2,3-butanedione modified ETF only possessed decreased activity with dimethylglycine-(DMGDH, 44%) and sarcosine- (SDH, 27%) dehydrogenases unlike the abolition with MCAD. Full protection of ETF from arginine modification by 2,3-butanedione was achieved using substrate-protected DMGDH, MCAD and SDH respectively. Cross-protection studies of ETF with the three dehydrogenases implied use of the same single arginine residue in the binding of all three dehydrogenases. These results lead us to conclude that this single arginine residue is essential in the binding of the ETF to MCAD, but only contributes partially to the binding of ETF to SDH and DMGDH and thus, the determinants of the dehydrogenase binding sites overlap but are not identical.

  5. TmiRUSite and TmiROSite scripts: searching for mRNA fragments with miRNA binding sites with encoded amino acid residues

    OpenAIRE

    Berillo, Olga; Régnier, Mireille; Ivashchenko, Anatoly

    2014-01-01

    microRNAs are small RNA molecules that inhibit the translation of target genes. microRNA binding sites are located in the untranslated regions as well as in the coding domains. We describe TmiRUSite and TmiROSite scripts developed using python as tools for the extraction of nucleotide sequences for miRNA binding sites with their encoded amino acid residue sequences. The scripts allow for retrieving a set of additional sequences at left and at right from the binding site. The scripts presents ...

  6. Fatty acid oxidation is required for active and quiescent brown adipose tissue maintenance and thermogenic programing.

    Science.gov (United States)

    Gonzalez-Hurtado, Elsie; Lee, Jieun; Choi, Joseph; Wolfgang, Michael J

    2018-01-01

    To determine the role of fatty acid oxidation on the cellular, molecular, and physiologic response of brown adipose tissue to disparate paradigms of chronic thermogenic stimulation. Mice with an adipose-specific loss of Carnitine Palmitoyltransferase 2 (Cpt2 A-/- ), that lack mitochondrial long chain fatty acid β-oxidation, were subjected to environmental and pharmacologic interventions known to promote thermogenic programming in adipose tissue. Chronic administration of β3-adrenergic (CL-316243) or thyroid hormone (GC-1) agonists induced a loss of BAT morphology and UCP1 expression in Cpt2 A-/- mice. Fatty acid oxidation was also required for the browning of white adipose tissue (WAT) and the induction of UCP1 in WAT. In contrast, chronic cold (15 °C) stimulation induced UCP1 and thermogenic programming in both control and Cpt2 A-/- adipose tissue albeit to a lesser extent in Cpt2 A-/- mice. However, thermoneutral housing also induced the loss of UCP1 and BAT morphology in Cpt2 A-/- mice. Therefore, adipose fatty acid oxidation is required for both the acute agonist-induced activation of BAT and the maintenance of quiescent BAT. Consistent with this data, Cpt2 A-/- BAT exhibited increased macrophage infiltration, inflammation and fibrosis irrespective of BAT activation. Finally, obese Cpt2 A-/- mice housed at thermoneutrality exhibited a loss of interscapular BAT and were refractory to β3-adrenergic-induced energy expenditure and weight loss. Mitochondrial long chain fatty acid β-oxidation is critical for the maintenance of the brown adipocyte phenotype both during times of activation and quiescence. Copyright © 2017 The Authors. Published by Elsevier GmbH.. All rights reserved.

  7. Discrimination between acid and alkali-labile phosphorylated residues on Immobilon: phosphorylation studies of nucleoside diphosphate kinase

    DEFF Research Database (Denmark)

    Biondi, R M; Walz, K; Issinger, O G

    1996-01-01

    of phosphoserine after strong acid hydrolysis of the histidine autophosphorylated enzyme is in fact a nonenzymatic transphosphorylation from phosphohistidine due to the harsh acid treatment. This methodology was also applied to in vivo phosphorylation studies of C. albicans NDP kinase. We believe...

  8. Bromopyruvate, an active site-directed inactivator of E. coli 2-keto-4-hydroxyglutarate(KHG) aldolase, modifies glutamic acid residue-45

    International Nuclear Information System (INIS)

    Vlahos, C.J.; Dekker, E.E.

    1987-01-01

    E. coli KHG-aldolase (2-keto-4-hydroxyglutarate ↔ pyruvate + glyoxylate), a novel trimeric Class I aldolase, requires one active-site lysine residue (Lys 133)/subunit for Schiff-base formation as well as one arginine residue (Arg 49)/subunit for catalytic activity. The substrate analog, 3-bromopyruvate (BRPY), causes a time- and concentration-dependent loss of KHG-aldolase activity. This inactivation is regarded as active site-directed since: (a) BRPY modification results in complete loss of enzymatic activity; (b) saturation kinetics are exhibited, suggesting that a reversible complex is formed between the aldolase and BRPY prior to the rate-limiting inactivation step; (c) over 90% of the initial aldolase activity is protected by either substrate, pyruvate or KHG; (d) 1.1 mol of 14 C-BRPY is bound/enzyme subunit. Peptide isolation and sequencing show that the incorporated radioactivity is associated with residue Glu-45. Denaturation of the enzyme with guanidine x HCl following treatment with excess 14 C-BRPY allows for the incorporation of carbon-14 at Cys-159 and Cys-180 as well. The presence of pyruvate protects Glu-45 from being esterified but does not prevent the alkylation of the two cysteine residues. These results suggest that Glu-45 is essential for the catalytic activity of E. coli KHG-aldolase, most likely functioning as the active-site amphoteric proton donor/acceptor moiety that is involved in the overall mechanism of the reaction catalyzed by this enzyme

  9. Quantitation of some amino-terminal residues in proteins using 3H-labelled dansyl chloride and 14C labelled amino acids

    International Nuclear Information System (INIS)

    Flengsrud, R.

    1979-01-01

    A method for quantitation of amino-terminal residues in proteins is presented. The method is a modification of a double isotope-labelling technique, using 3 H-labelled dansyl chloride and 14 C-labelled amino acids as internal standards. The method is demonstrated on human fibrinogen, horse myoglobin and on mouse myoloma IgA. A linear relationship between the ratio 3 H/ 14 C in the separated amino-terminal amino acid of the protein and the amount of protein added in the labelling mixture was obtained with standard deviations of +- 7.4%, +-3.4% and +-10.3%, respectively. An application of the method is demonstrated by measuring the increase in amino-terminal glycine in fibrinogen following the proteolytic action of thrombin. The method seems to be useful when 0.1 nmol or more of protein is used. (author)

  10. Use of radioactive glucosamine in the perfused rat liver to prepare α1-acid glycoprotein (orosomucoid) with 3H- or 14C-labelled sialic acid and N-acetylglucosamine residues

    International Nuclear Information System (INIS)

    Aronson, N.N. Jr.

    1982-01-01

    A method was developed whereby [1- 14 C]glucosamine was used in a perfused rat liver system to prepare over 2 mg of α 1 -acid glycoprotein with highly radioactive sialic acid and glucosamine residues. The liver secreted radioactive α 1 -acid glycoprotein over a 4-6 h period, and this glycoprotein was purified from the perfusate by chromatography on DEAE-cellulose at pH3.6. The sialic acid on the isolated glycoprotein had a specific radioactivity of 3.1 Ci/mol, whereas the glucosamine-specific radioactivity was 4.3 Ci/mole. The latter amino-sugar residues on the isolated protein were only 13-fold less radioactive than the initially added [1- 14 C]glucosamine. Orosomucoid with a specific radioactivity of 31.3 μCi/mg of protein was obtainable by using [6- 3 H]glucosamine. Many other radioactive glycoproteins were found to be secreted into the perfusate by the liver. Thus this experimental system should prove useful for obtaining other serum glycoproteins with highly radioactive sugar moieties. (author)

  11. GLABROUS INFLORESCENCE STEMS (GIS) is required for trichome branching through gibberellic acid signaling in Arabidopsis.

    Science.gov (United States)

    An, Lijun; Zhou, Zhongjing; Su, Sha; Yan, An; Gan, Yinbo

    2012-02-01

    Cell differentiation generally corresponds to the cell cycle, typically forming a non-dividing cell with a unique differentiated morphology, and Arabidopsis trichome is an excellent model system to study all aspects of cell differentiation. Although gibberellic acid is reported to be involved in trichome branching in Arabidopsis, the mechanism for such signaling is unclear. Here, we demonstrated that GLABROUS INFLORESCENCE STEMS (GIS) is required for the control of trichome branching through gibberellic acid signaling. The phenotypes of a loss-of-function gis mutant and an overexpressor showed that GIS acted as a repressor to control trichome branching. Our results also show that GIS is not required for cell endoreduplication, and our molecular and genetic study results have shown that GIS functions downstream of the key regulator of trichome branching, STICHEL (STI), to control trichome branching through the endoreduplication-independent pathway. Furthermore, our results also suggest that GIS controls trichome branching in Arabidopsis through two different pathways and acts either upstream or downstream of the negative regulator of gibbellic acid signaling SPINDLY (SPY).

  12. A chloroplast lipoxygenase is required for wound-induced jasmonic acid accumulation in Arabidopsis.

    Science.gov (United States)

    Bell, E; Creelman, R A; Mullet, J E

    1995-09-12

    Plant lipoxygenases are thought to be involved in the biosynthesis of lipid-derived signaling molecules. The potential involvement of a specific Arabidopsis thaliana lipoxygenase isozyme, LOX2, in the biosynthesis of the plant growth regulators jasmonic acid (JA) and abscisic acid was investigated. Our characterization of LOX2 indicates that the protein is targeted to chloroplasts. The physiological role of this chloroplast lipoxygenase was analyzed in transgenic plants where cosuppression reduced LOX2 accumulation. The reduction in LOX2 levels caused no obvious changes in plant growth or in the accumulation of abscisic acid. However, the wound-induced accumulation of JA observed in control plants was absent in leaves of transgenic plants that lacked LOX2. Thus, LOX2 is required for the wound-induced synthesis of the plant growth regulator JA in leaves. We also examined the expression of a wound- and JA-inducible Arabidopsis gene, vsp, in transgenic and control plants. Leaves of transgenic plants lacking LOX2 accumulated less vsp mRNA than did control leaves in response to wounding. This result suggests that wound-induced JA (or some other LOX2-requiring component of the wound response pathway) is involved in the wound-induced regulation of this gene.

  13. Daily Intake of Protein from Cod Residual Material Lowers Serum Concentrations of Nonesterified Fatty Acids in Overweight Healthy Adults: A Randomized Double-Blind Pilot Study

    Directory of Open Access Journals (Sweden)

    Iselin Vildmyren

    2018-06-01

    Full Text Available Improved process technologies have allowed fishing vessels to utilize residuals from cod fillet production (head, backbone, skin, cuttings, and entrails and convert this to high-quality protein powders for human consumption. In this double-blind pilot study, 42 healthy overweight or obese adults were randomized to three experimental groups consuming tablets corresponding to 6 g/day of proteins from cod residuals as presscake meal (Cod-PC, presscake and stickwater meal (Cod-PCW, or placebo tablets (control for eight weeks. The primary outcome of this study was changes in metabolites related to glucose regulation in overweight or obese healthy adults after intake of proteins from cod residuals. Cod-PC supplementation decreased postprandial serum nonesterified fatty acids (NEFA concentration and increased gene expressions of diglyceride acyltransferase 1 and 2 in subcutaneous adipose tissue compared with controls. Fasting insulin increased while fasting NEFA and 120-min postprandial glucose decreased within the Cod-PC group, but these changes did not differ from the other groups. In conclusion, supplementation with Cod-PC beneficially affected postprandial serum NEFA concentration compared with the other groups in overweight or obese adults. Supplementation with Cod-PCW, which contains a higher fraction of water-soluble protein compared to Cod-PC, did not affect serum markers of glucose regulation.

  14. Identification of the roles of individual amino acid residues of the helix E of the major antenna of photosystem II (LHCII) by alanine scanning mutagenesis.

    Science.gov (United States)

    Liu, Cheng; Rao, Yan; Zhang, Lei; Yang, Chunhong

    2014-10-01

    The functions of the helix E (W97-F105), an amphiphilic lumenal 310 helix of the major antenna of photosystem II (LHCII), are still unidentified. To elucidate the roles of individual amino acid residue of the helix E, alanine scanning mutagenesis has been performed to mutate every residue of this domain to alanine. The influence of every alanine substitution on the structure and function of LHCII has been investigated biochemically and spectroscopically. The results show that all mutations have little impact on the pigment binding and configuration. However, many mutants presented decreased thermo- or photo-stability compared with the wild type, highlighting the significance of this helix to the stability of LHCII. The most critical residue for stability is W97. The mutant W97A yielded very fragile trimeric pigment protein complexes. The structural analysis revealed that the hydrogen bonding and aromatic interactions between W97, F195, F194 and a water molecule contributed greatly to the stability of LHCII. Moreover, Q103A and F105A have been identified to be able to reinforce the tendency of aggregation in vitro. The structural analysis suggested that the enhancement in aggregation formation for Q103A and F105A might be attributed to the changing hydrophobicity of the region. © The Authors 2014. Published by Oxford University Press on behalf of the Japanese Biochemical Society. All rights reserved.

  15. NPPD: A Protein-Protein Docking Scoring Function Based on Dyadic Differences in Networks of Hydrophobic and Hydrophilic Amino Acid Residues

    Directory of Open Access Journals (Sweden)

    Edward S. C. Shih

    2015-03-01

    Full Text Available Protein-protein docking (PPD predictions usually rely on the use of a scoring function to rank docking models generated by exhaustive sampling. To rank good models higher than bad ones, a large number of scoring functions have been developed and evaluated, but the methods used for the computation of PPD predictions remain largely unsatisfactory. Here, we report a network-based PPD scoring function, the NPPD, in which the network consists of two types of network nodes, one for hydrophobic and the other for hydrophilic amino acid residues, and the nodes are connected when the residues they represent are within a certain contact distance. We showed that network parameters that compute dyadic interactions and those that compute heterophilic interactions of the amino acid networks thus constructed allowed NPPD to perform well in a benchmark evaluation of 115 PPD scoring functions, most of which, unlike NPPD, are based on some sort of protein-protein interaction energy. We also showed that NPPD was highly complementary to these energy-based scoring functions, suggesting that the combined use of conventional scoring functions and NPPD might significantly improve the accuracy of current PPD predictions.

  16. Protein Thermostability Is Owing to Their Preferences to Non-Polar Smaller Volume Amino Acids, Variations in Residual Physico-Chemical Properties and More Salt-Bridges.

    Science.gov (United States)

    Panja, Anindya Sundar; Bandopadhyay, Bidyut; Maiti, Smarajit

    2015-01-01

    Protein thermostability is an important field for its evolutionary perspective of mesophilic versus thermophilic relationship and for its industrial/ therapeutic applications. Presently, a total 400 (200 thermophilic and 200 mesophilic homologue) proteins were studied utilizing several software/databases to evaluate their amino acid preferences. Randomly selected 50 homologous proteins with available PDB-structure of each group were explored for the understanding of the protein charges, isoelectric-points, hydrophilicity, hydrophobicity, tyrosine phosphorylation and salt-bridge occurrences. These 100 proteins were further probed to generate Ramachandran plot/data for the gross secondary structure prediction in and comparison between the thermophilic and mesophilic proteins. Present results strongly suggest that nonpolar smaller volume amino acids Ala (χ2 = 238.54, psalt bridges in this study. The average percentage of salt-bridge of thermophiles is found to be higher by 20% than their mesophilic homologue. The GLU-HIS and GLU-LYS salt-bridge dyads are calculated to be significantly higher (psalt-bridges and smaller volume nonpolar residues (Gly, Ala and Val) and lesser occurrence of bulky polar residues in the thermophilic proteins. A more stoichiometric relationship amongst these factors minimized the hindrance due to side chain burial and increased compactness and secondary structural stability in thermophilic proteins.

  17. Facile and Low-Cost Preparation of Nb/Al Oxide Catalyst with High Performance for the Conversion of Kiwifruit Waste Residue to Levulinic Acid

    Directory of Open Access Journals (Sweden)

    Rui Wang

    2015-09-01

    Full Text Available The kiwifruit industry is booming worldwide. As a result, a great deal of kiwifruit waste residue (KWR containing monosaccharides is produced and discarded. This material shows great potential for the production of platform chemicals. In this study, a series of Nb/Al oxide catalysts were synthesized via a facile and low-cost coprecipitation method, and their structures were characterized using: thermal gravimetric analysis (TGA, XRD, FESEM, TEM, X-ray photoelectron spectroscopy (XPS, NH3-TPD, N2 adsorption-desorption, and FTIR-Pyridine adsorption. Experimental results of sugar-to-levulinic acid (LA conversion revealed that the 20%Nb/Al oxide catalyst provided the highest catalytic performance and durability in terms of LA yield from fructose (74.2% at 463 K after 10 min and from glucose (47.5% at 473 K after 15 min. Notably, the 20% Nb/Al oxide catalyst with a 10% dosage is capable of converting kiwifruit waste residue to LA at 473 K after 10 min. In conclusion, the enhanced catalytic performance was obtained due to the high acidity, and large surface areaof Nb/Al oxide catalyst.

  18. Identification of oligo-N-glycolylneuraminic acid residues in mammal-derived glycoproteins by a newly developed immunochemical reagent and biochemical methods.

    Science.gov (United States)

    Sato, C; Kitajima, K; Inoue, S; Inoue, Y

    1998-01-30

    The occurrence of the alpha2-->8-linked oligomeric form of N-glycolylneuraminic acid (oligo-Neu5Gc) residues in mammalian glycoproteins was unequivocally demonstrated using a newly developed anti-oligo/poly-Neu5Gc monoclonal antibody as well as by chemical and biochemical methods. First, the antibody, designated mAb.2-4B, which specifically recognized oligo/poly-Neu5Gc with a degree of polymerization of >2, was developed by establishing a hybridoma cell line from P3U1 myeloma cells fused with splenocytes from an MRL autoimmune mouse immunized with dipalmitoylphosphatidylethanolamine-conjugated oligo/poly-Neu5Gc. Second, oligo-Neu5Gc was shown to occur in glycoproteins derived from pig spleen by Western blot analysis using mAb.2-4B, which was also confirmed by fluorometric high performance liquid chromatographic analysis of the product of periodate oxidation/reduction/acid hydrolysis of the purified glycopeptide fractions and by TLC and 600-MHz 1H NMR spectroscopic analysis of their mild acid hydrolysates. Finally, the ubiquitous occurrence of oligo-Neu5Gc chains as glycoproteinaceous components in Wistar rat tissue was immunochemically indicated. This is the first example demonstrating the diversity in oligo/poly-Sia structure in mammalian glycoproteins, where only poly-N-acetylneuraminic acid is known to occur. Such diversity in oligo/poly-Sia structure also implicates a diverged array of biological functions of this glycan unit in glycoproteins.

  19. Molecular evolution of the nicotinic acid requirement within the Shigella/EIEC pathotype.

    Science.gov (United States)

    Di Martino, Maria Letizia; Fioravanti, Rosa; Barbabella, Giada; Prosseda, Gianni; Colonna, Bianca; Casalino, Mariassunta

    2013-12-01

    Nicotinamide adenine dinucleotide (NAD) is a crucial cofactor in several anabolic and catabolic reactions. NAD derives from quinolinic acid (QUIN) which in Escherichia coli is obtained through a pyridine salvage pathway or a de novo synthesis pathway. In the latter case, two enzymes, L-aspartate oxidase (NadB) and quinolinate synthase (NadA), are required for the synthesis of QUIN. In contrast to its E. coli ancestor, Shigella spp., the causative agent of bacillary dissentery, lacks the de novo pathway and strictly requires nicotinic acid for growth (Nic⁻ phenotype). This phenotype depends on the silencing of the nadB and nadA genes and its pathoadaptive nature is suggested by the observation that QUIN attenuates the Shigella invasive process. Shigella shares the pathogenicity mechanism with enteronvasive E. coli (EIEC), a group of pathogenic E. coli. On the basis of this similarity EIEC and Shigella have been grouped into a single E. coli pathotype. However EIEC strains do not constitute a homogeneous group and do not possess the complete set of characters that define Shigella strains. In this work we have analysed thirteen EIEC strains belonging to different serotypes and originating from different geographic areas. We show that, in contrast to Shigella, only some EIEC strains require nicotinic acid for growth in minimal medium. Moreover, by studying the emergence of the Nic⁻ phenotype in all serotypes of S. flexneri, as well as in S. sonnei and S. dysenteriae, we describe which molecular rearrangements occurred and which mutations are responsible for the inactivation of the nadA and nadB genes. Our data confirm that the genome of Shigella is extremely dynamic and support the hypothesis that EIEC might reflect an earlier stage of the pathoadaptation process undergone by Shigella. Copyright © 2013. Published by Elsevier GmbH.

  20. Hereditary folate malabsorption: A positively charged amino acid at position 113 of the proton-coupled folate transporter (PCFT/SLC46A1) is required for folic acid binding

    International Nuclear Information System (INIS)

    Lasry, Inbal; Berman, Bluma; Glaser, Fabian; Jansen, Gerrit; Assaraf, Yehuda G.

    2009-01-01

    The proton-coupled folate transporter (PCFT/SLC46A1) mediates intestinal folate uptake at acidic pH. Some loss of folic acid (FA) transport mutations in PCFT from hereditary folate malabsorption (HFM) patients cluster in R113, thereby suggesting a functional role for this residue. Herein, unlike non-conservative substitutions, an R113H mutant displayed 80-fold increase in the FA transport Km while retaining parental Vmax, hence indicating a major fall in folate substrate affinity. Furthermore, consistent with the preservation of 9% of parental transport activity, R113H transfectants displayed a substantial decrease in the FA growth requirement relative to mock transfectants. Homology modeling based on the crystal structures of the Escherichia coli transporter homologues EmrD and glycerol-3-phosphate transporter revealed that the R113H rotamer properly protrudes into the cytoplasmic face of the minor cleft normally occupied by R113. These findings constitute the first demonstration that a basic amino acid at position 113 is required for folate substrate binding.

  1. Exchanging a single amino acid residue generates or weakens a +2 cellooligosaccharide binding subsite in rice β-glucosidases.

    Science.gov (United States)

    Sansenya, Sompong; Maneesan, Janjira; Cairns, James R Ketudat

    2012-04-01

    Os3BGlu6, Os3BGlu7, and Os4BGlu12 are rice glycoside hydrolase family 1 β-glucosidases, the structures of which have been solved by X-ray crystallography. In complex structures, Os3BGlu7 residue Asn245 hydrogen bonds to the second sugar in the +1 subsite for laminaribiose and the third sugar in the +2 subsite for cellotetraose and cellopentaose. The corresponding Os3BGlu6 residue, Met251, appears to block the binding of cellooligosaccharides at the +2 subsite, whereas His252 in this position in Os4BGlu12 could hydrogen bond to oligosaccharides. Mutation of Os3BGlu6 Met251 to Asn resulted in a 15-fold increased k(cat)/K(m) value for hydrolysis of laminaribiose compared to wild type Os3BGlu6 and 9 to 24-fold increases for cellooligosaccharides with degrees of polymerization (DP) of 2-5. On the other hand, mutation of Os3BGlu7 Asn245 to Met decreased the k(cat)/K(m) of hydrolysis by 6.5-fold for laminaribiose and 17 to 30-fold for cellooligosaccharides with DP >2, while mutation of Os4BGlu12 His252 to Met decreased the corresponding k(cat)/K(m) values 2 to 6-fold. Copyright © 2012 Elsevier Ltd. All rights reserved.

  2. Regulatory Considerations for the Long Term Cooling Safe Shutdown Requirements of the Passive Residual Heat Removal Systems in Advanced Reactors

    International Nuclear Information System (INIS)

    Sim, S. K.; Bae, S. H.; Kim, Y. S.; Hwang, Min Jeong; Bang, Young Seok; Hwang, Taesuk

    2016-01-01

    USNRC approved safe shutdown at 215.6 .deg. C for a safe and long term cooling state for the redundant passive RHRSs by SECY-94-084. USNRC issued COLA(Combined Construction and Operating License) for the Levy County NP Unit-1/2 for the AP1000 passive RHRSs in 2014. Korea Hydro and Nuclear Power(KHNP) is developing APR+ and adopted Passive Auxiliary Feedwater System(PAFS) as a new passive RHRS design. Korea Institute of Nuclear Safety(KINS) has been developing regulatory guides for the advanced safety design features of the advanced ALWRs which has plan to construct in near future in Korea[5]. Safety and regulatory issues as well as the safe shut down requirements of the passive RHRS are discussed and considerations in developing regulatory guides for the passive RHRS are presented herein. Passive RHRSs have been introduced as new safety design features for the advanced reactors under development in Korea. These passive RHRSs have potential advantages over existing active RHRS, however, their functions are limited due to inherent ability of passive heat removal processes. It is high time to evaluate the performance of the passive PRHRs and develop regulatory guides for the safety as well as the performance analyses of the passive RHRS

  3. Influence of bleaching on flavor of 34% whey protein concentrate and residual benzoic acid concentration in dried whey products

    Science.gov (United States)

    Previous studies have shown that bleaching negatively affects the flavor of 70% whey protein concentrate (WPC70), but bleaching effects on lower-protein products have not been established. Benzoyl peroxide (BP), a whey bleaching agent, degrades to benzoic acid (BA) and may elevate BA concentrations...

  4. Influence of Bleaching on Flavor of 34% Whey Protein Concentrate and Residual Benzoic Acid Concentration in Dried Whey Proteins

    Science.gov (United States)

    Previous studies have shown that bleaching negatively affects the flavor of 70% whey protein concentrate (WPC70), but bleaching effects on lower-protein products have not been established. Benzoyl peroxide (BP), a whey bleaching agent, degrades to benzoic acid (BA) and may elevate BA concentrations...

  5. Triazacyclophane (TAC)-scaffolded histidine and aspartic acid residues as mimics of non-heme metalloenzyme active sites

    NARCIS (Netherlands)

    Albada, H.B.; Soulimani, F.; Jacobs, H.J.F.; Versluis, C.; Weckhuysen, B.M.; Liskamp, R.M.J.

    2012-01-01

    We describe the synthesis and coordination behaviour to copper(II) of two close structural triazacyclophane-based mimics of two often encountered aspartic acid and histidine containing metalloenzyme active sites. Coordination of these mimics to copper(I) and their reaction with molecular oxygen

  6. MOLECULAR MODELING STUDY OF THE CONTRIBUTIONS OF SIDE AMINO ACID RESIDUES OF POLYMYXIN B3 TO ITS BINDING WITH E.COLI OUTER MEMBRANE LIPOPOLYSACCHARIDE

    Directory of Open Access Journals (Sweden)

    Lisnyak Yu. V.

    2014-12-01

    Full Text Available Last decades, antimicrobial peptides (AMPs are the subject of intense investigations aimed to develop effective drugs against extremely resistant nosocomial bacterial pathogens (especially Gram-negative bacteria. In particular, there has been greatly renewed interest to polymyxins, the representatives of AMPs which are specific and highly potent against Gram-negative bacteria, but have potential nephrotoxic side effect. A prerequisite of purposeful enhancement of therapeutic properties of polymyxins is a detailed knowledge of the molecular mechanisms of their interactions with cell targets. Lipopolysaccharide (LPS, the main component of the outer leaflet of outer membrane of gram-negative bacteria, is a primary cell target of polymyxins. The aim of the paper was to study the peculiarities of molecular interactions of polymyxin В3 with lipopolysaccharide of the outer membrane of gram-negative bacterium. Materials and methods The complexes of polymyxin В3 (PmВ3 and its alaninederivatives with E. coli outer membrane lipopolysaccharide were built and studied by molecular modeling methods (minimization, simulated annealing, docking. Atom coordinates of polymyxin В3 and LPS structures were taken from nuclear magnetic resonance and X-ray crystallography experiments, respectively. The AMBER03 force field was used with a 1.05 nm force cutoff. Longrange electrostatic interactions were treated by the Particle Mesh Ewald method. Results and discussion Alanine scanning of PmВ3 molecule has been carried out and the role of its side amino acid residues in the formation of complex with lipopolysaccharide has been investigated. It has been shown that substitutions of polymyxin’s Dab residues in positions 1, 3, 5, 8 and 9 for alanine markedly reduce the binding energy of PmB3-LPS complex, where as the similar substitutions of residues in positions 2, 6, 7 and 10 leave the binding energy virtually unchanged. Structural aspects of antimicrobial action of

  7. Contribution of post-harvest agricultural paddy residue fires in the N.W. Indo-Gangetic Plain to ambient carcinogenic benzenoids, toxic isocyanic acid and carbon monoxide

    Science.gov (United States)

    Praphulla Chandra, Boggarapu; Sinha, Vinayak

    2016-04-01

    In the North West Indo-Gangetic Plain (N.W.IGP), large scale post-harvest paddy residue fires occur every year during the months of October-November. This anthropogenic perturbation causes contamination of the atmospheric environment with adverse impacts on regional air quality posing health risks for the population exposed to high concentrations of carcinogens such as benzene and toxic VOCs such as isocyanic acid. These gases and carbon monoxide are known to be emitted from biomass fires along with acetonitrile. Yet no long-term in-situ measurements quantifying the impact of this activity have been carried out in the N.W. IGP. Using high quality continuous online in-situ measurements of these gases at a strategic downwind site over a three year period from 2012 to 2014, we demonstrate the strong impact of this anthropogenic emission activity on ambient concentrations of these gases. In contrast to the pre-paddy harvest period, excellent correlation of benzenoids, isocyanic acid and CO with acetonitrile (a biomass burning chemical tracer); (r ≥ 0.82) and distinct VOC/acetonitrile emission ratios were observed for the post-paddy harvest period which was also characterized by high ambient concentrations of these species. The average concentrations of acetonitrile (1.62 ± 0.18 ppb), benzene (2.51 ± 0.28 ppb), toluene (3.72 ± 0.41 ppb), C8-aromatics (2.88 ± 0.30 ppb), C9-aromatics (1.55 ± 0.19 ppb) and CO (552 ± 113 ppb) in the post-paddy harvest periods were about 1.5 times higher than the annual average concentrations. For isocyanic acid, a compound with both primary and secondary sources, the concentration in the post-paddy harvest period was 0.97 ± 0.17 ppb. The annual average concentrations of benzene, a class A carcinogen, exceeded the annual exposure limit of 1.6 ppb at NTP mandated by the National Ambient Air Quality Standard of India (NAAQS). We show that mitigating the post-harvest paddy residue fires can lower the annual average concentration of

  8. Analysis of ethyl acrylate (EA) and acrylic acid (AA) residues from rat tissues following oral ea dosing

    International Nuclear Information System (INIS)

    Udinsky, J.R.; Frederick, C.B.

    1990-01-01

    Gavage dosing of rats with EA at high dose levels (100 or 200 mg/kg) has resulted in tumors at the dosing site, forestomach (FST), but no lesions of the glandular stomach (GST) or other remote tissues. Since previous in vitro studies have demonstrated that EA is very rapidly metabolized to AA and glutathione conjugates, EA and AA residues were analyzed 0-24 hr following gavage dosing of non-fasted F-344/N male rats with [1- 14 C]EA in corn oil at 10, 50, and 200 mg/kg. Analysis of total 14 C indicated that the dose solution was primarily in the FST at ≥5 min after dosing, although 14 C was detected in the GST, duodenum, and small intestine (attributed to distension of the FST and leakage from the FST to the GST). HPLC analysis of the gut contents, gut wall, liver, kidneys, lungs, and blood indicated that EA and AA could only be detected at ≥15 min in the FST and GST contents, and in the FST tissue. AA alone was detected in the GST tissue, duodenum tissue and contents, and small intestine tissue and contents. The minimum level of detection was 0.0005% of the dose. The remaining 14 C was primarily attributed to binding to the gut contents or bioincorporation of AA. The detection of EA and AA residues only in the upper gastrointestinal tract following gavage dosing is consistent with rapid detoxification of EA by hydrolysis and conjugation which prevents toxicity at sites remote form the site of dosing

  9. Phenotypic and genetic relationships of residual feed intake measures and their component traits with fatty acid composition in subcutaneous adipose of beef cattle.

    Science.gov (United States)

    Zhang, F; Ekine-Dzivenu, C; Vinsky, M; Basarab, J A; Aalhus, J L; Dugan, M E R; Li, C

    2017-07-01

    Feed efficiency is of particular interest to the beef industry because feed is the largest variable cost in production and fatty acid composition is emerging as an important trait, both economically and socially, due to the potential implications of dietary fatty acids on human health. Quantifying correlations between feed efficiency and fatty acid composition will contribute to construction of optimal multiple-trait selection indexes to maximize beef production profitability. In the present study, we estimated phenotypic and genetic correlations of feed efficiency measures including residual feed intake (RFI), RFI adjusted for final ultrasound backfat thickness (RFIf); their component traits ADG, DMI, and metabolic BW; and final ultrasound backfat thickness measured at the end of feedlot test with 25 major fatty acids in the subcutaneous adipose tissues of 1,366 finishing steers and heifers using bivariate animal models. The phenotypic correlations of RFI and RFIf with the 25 individual and grouped fatty acid traits were generally low (ratio (0.52 ± 0.29 and 0.45 ± 0.31, respectively), 18:2-6 (0.45 ± 0.18 and 0.40 ± 0.19, respectively), -6 (0.43 ± 0.18 and 0.38 ± 0.19, respectively), PUFA (0.42 ± 0.18 and 0.36 ± 0.20, respectively), and 9-16:1 (-0.43 ± 0.20 and -0.33 ± 0.22, respectively) were observed. Hence, selection for low-RFI or more efficient beef cattle will improve fatty acid profiles by lowering the content of -6 PUFA, thus reducing the ratio of -6 to -3 along with increasing the amount of 9-16:1. Moderate to moderately high genetic correlations were also observed for DMI with 9-14:1 (-0.32 ± 0.17) and the sum of CLA analyzed (SumCLA; -0.45 ± 0.21), suggesting that selection of beef cattle with lower DMI will lead to an increase amount of 9-14:1 and SumCLA in the subcutaneous adipose tissue. However, unfavorable genetic correlations were detected for ADG with 11-18:1 (-0.38 ± 0.23) and SumCLA (-0.73 ± 0.26), implying that selection of beef

  10. Ethanol production from residual wood chips of cellulose industry: acid pretreatment investigation, hemicellulosic hydrolysate fermentation, and remaining solid fraction fermentation by SSF process.

    Science.gov (United States)

    Silva, Neumara Luci Conceição; Betancur, Gabriel Jaime Vargas; Vasquez, Mariana Peñuela; Gomes, Edelvio de Barros; Pereira, Nei

    2011-04-01

    Current research indicates the ethanol fuel production from lignocellulosic materials, such as residual wood chips from the cellulose industry, as new emerging technology. This work aimed at evaluating the ethanol production from hemicellulose of eucalyptus chips by diluted acid pretreatment and the subsequent fermentation of the generated hydrolysate by a flocculating strain of Pichia stipitis. The remaining solid fraction generated after pretreatment was subjected to enzymatic hydrolysis, which was carried out simultaneously with glucose fermentation [saccharification and fermentation (SSF) process] using a strain of Saccharomyces cerevisiae. The acid pretreatment was evaluated using a central composite design for sulfuric acid concentration (1.0-4.0 v/v) and solid to liquid ratio (1:2-1:4, grams to milliliter) as independent variables. A maximum xylose concentration of 50 g/L was obtained in the hemicellulosic hydrolysate. The fermentation of hemicellulosic hydrolysate and the SSF process were performed in bioreactors and the final ethanol concentrations of 15.3 g/L and 28.7 g/L were obtained, respectively.

  11. A thioesterase bypasses the requirement for exogenous fatty acids in the plsX deletion of Streptococcus pneumoniae

    NARCIS (Netherlands)

    Parsons, J.B.; Frank, M.W.; Eleveld, M.J.; Schalkwijk, J.; Broussard, T.C.; Jonge, M.I. de; Rock, C.O.

    2015-01-01

    PlsX is an acyl-acyl carrier protein (ACP):phosphate transacylase that interconverts the two acyl donors in Gram-positive bacterial phospholipid synthesis. The deletion of plsX in Staphylococcus aureus results in a requirement for both exogenous fatty acids and de novo type II fatty acid

  12. TmiRUSite and TmiROSite scripts: searching for mRNA fragments with miRNA binding sites with encoded amino acid residues.

    Science.gov (United States)

    Berillo, Olga; Régnier, Mireille; Ivashchenko, Anatoly

    2014-01-01

    microRNAs are small RNA molecules that inhibit the translation of target genes. microRNA binding sites are located in the untranslated regions as well as in the coding domains. We describe TmiRUSite and TmiROSite scripts developed using python as tools for the extraction of nucleotide sequences for miRNA binding sites with their encoded amino acid residue sequences. The scripts allow for retrieving a set of additional sequences at left and at right from the binding site. The scripts presents all received data in table formats that are easy to analyse further. The predicted data finds utility in molecular and evolutionary biology studies. They find use in studying miRNA binding sites in animals and plants. TmiRUSite and TmiROSite scripts are available for free from authors upon request and at https: //sites.google.com/site/malaheenee/downloads for download.

  13. Bioethanol production from microwave-assisted acid or alkali-pretreated agricultural residues of cassava using separate hydrolysis and fermentation (SHF).

    Science.gov (United States)

    Pooja, N S; Sajeev, M S; Jeeva, M L; Padmaja, G

    2018-01-01

    The effect of microwave (MW)-assisted acid or alkali pretreatment (300 W, 7 min) followed by saccharification with a triple enzyme cocktail (Cellic, Optimash BG and Stargen) with or without detoxification mix on ethanol production from three cassava residues (stems, leaves and peels) by Saccharomyces cerevisiae was investigated. Significantly higher fermentable sugar yields (54.58, 47.39 and 64.06 g/L from stems, leaves and peels, respectively) were obtained after 120 h saccharification from MW-assisted alkali-pretreated systems supplemented (D+) with detoxification chemicals (Tween 20 + polyethylene glycol 4000 + sodium borohydride) compared to the non-supplemented (D0) or MW-assisted acid-pretreated systems. The percentage utilization of reducing sugars during fermentation (48 h) was also the highest (91.02, 87.16 and 89.71%, respectively, for stems, leaves and peels) for the MW-assisted alkali-pretreated (D+) systems. HPLC sugar profile indicated that glucose was the predominant monosaccharide in the hydrolysates from this system. Highest ethanol yields ( Y E , g/g), fermentation efficiency (%) and volumetric ethanol productivity (g/L/h) of 0.401, 78.49 and 0.449 (stems), 0.397, 77.71 and 0.341 (leaves) and 0.433, 84.65 and 0.518 (peels) were also obtained for this system. The highest ethanol yields (ml/kg dry biomass) of ca. 263, 200 and 303, respectively, for stems, leaves and peels from the MW-assisted alkali pretreatment (D+) indicated that this was the most effective pretreatment for cassava residues.

  14. Simultaneous requirement of carbon dioxide and abscisic acid for stomatal closing in Xanthium strumarium L.

    Science.gov (United States)

    Raschke, K

    1975-01-01

    Open stomata of detached leaves of Xanthium strumarium L. closed only when carbon dioxide and abscisic acid (ABA) were presented simultaneously. Three parameters of stomatal closing were determined after additions of ABA to the irrigation water of detached leaves, while the leaves were exposed to various CO2 concentrations ([CO2]s) in the air; a) the delay between addition of ABA and a reduction of stomatal conductance by 5%, b) the velocity of stomatal closing, and c) the new conductance. Changes in all three parameters showed that stomatal responses to ABA were enhanced by CO2; this effect followed saturation kinetics. Half saturation occurred at an estimated [CO2] in the stomatal pore of 200 μl l(-1). With respect to ABA, stomata responded in normal air with half their maximal amplitude at [ABA]s between 10(-6) and 10(-5) M(+-)-ABA. The amounts of ABA taken up by the leaves during the delay increased with a power strumarium.Based on earlier findings and on the results of this investigation it is suggested that stomata close if the cytoplasm of the guard cells contains much malate and H(+). The acid content in turn is determined by the relative rates of production of malic acid (from endogenous as well as exogenous CO2) and its removal (by transport of the anion into the vacuole and exchange of the H(+) for K(+) with the environment of the guard cells). The simultaneous requirement of CO2 and ABA for stomatal closure leads to the inference that ABA inhibits the expulsion of H(+) from guard cells.

  15. Synthesis and NMR characterization of dendrimers based on 2, 2-bis-(hydroxymethyl-propanoic acid (bis-HMPA containing peripheral amino acid residues for gene transfection

    Directory of Open Access Journals (Sweden)

    Silvana Alfei

    2017-08-01

    Full Text Available Dendrimers, the emerging man made, highly branched, star-shaped macromolecules with nanometer-scale dimensions are well known for their well defined and high controlled architecture, their versatility and high functionality and are of eminent interest in nanomedical applications such as drug delivery, gene transfection, and imaging. In this paper, versatile protocols for the synthesis of polyester-based, hydrolysable, polycationic dendrimers have been setup. A fourth generation dendrimer equipped with 48 peripheral hydroxyl groups was prepared from 2,2-bis(hydroxymethylpropanoic acid and was used for grafting BOC-amino acids or as “hypercores” on which dendrons functionalized with BOC-amino acids were attached. A library of 15 polycationic homo- and hetero-dendrimers in the form of hydrochloride was obtained. Their structures and composition were confirmed by NMR analysis and by experimental molecular weight computed by volumetric titration. Their buffer capacity and results obtained from cytotoxicity assays and tests of binding with both pDNA and siRNA were very satisfactory.

  16. Genetic Analysis of Diaminopimelic Acid- and Lysine-Requiring Mutants of Escherichia coli1

    Science.gov (United States)

    Bukhari, Ahmad I.; Taylor, Austin L.

    1971-01-01

    Several diaminopimelic acid (DAP)- and lysine-requiring mutants of Escherichia coli were isolated and studied by genetic, physiological, and biochemical means. The genes concerned with DAP-lysine synthesis map at several different sites on the E. coli chromosome and, therefore, do not constitute a single operon. Three separate loci affecting DAP synthesis are located in the 0 to 2.5 min region of the genetic map. The order of the loci in this region is thr-dapB-pyrA-ara-leu-pan-dapC-tonA-dapD. Two additional DAP genes map in the region between min 47 and 48, with the gene order being gua-dapA-dapE-ctr. The lys locus at min 55 determines the synthesis of the enzyme DAP decarboxylase, which catalyzes the conversion of DAP into lysine. The order of the genes in this region is serA-lysA-thyA. PMID:4926684

  17. Genetic analysis of diaminopimelic acid- and lysine-requiring mutants of Escherichia coli.

    Science.gov (United States)

    Bukhari, A I; Taylor, A L

    1971-03-01

    Several diaminopimelic acid (DAP)- and lysine-requiring mutants of Escherichia coli were isolated and studied by genetic, physiological, and biochemical means. The genes concerned with DAP-lysine synthesis map at several different sites on the E. coli chromosome and, therefore, do not constitute a single operon. Three separate loci affecting DAP synthesis are located in the 0 to 2.5 min region of the genetic map. The order of the loci in this region is thr-dapB-pyrA-ara-leu-pan-dapC-tonA-dapD. Two additional DAP genes map in the region between min 47 and 48, with the gene order being gua-dapA-dapE-ctr. The lys locus at min 55 determines the synthesis of the enzyme DAP decarboxylase, which catalyzes the conversion of DAP into lysine. The order of the genes in this region is serA-lysA-thyA.

  18. Development of short and highly potent self-assembling elastin-derived pentapeptide repeats containing aromatic amino acid residues.

    Science.gov (United States)

    Taniguchi, Suguru; Watanabe, Noriko; Nose, Takeru; Maeda, Iori

    2016-01-01

    Tropoelastin is the primary component of elastin, which forms the elastic fibers that make up connective tissues. The hydrophobic domains of tropoelastin are thought to mediate the self-assembly of elastin into fibers, and the temperature-mediated self-assembly (coacervation) of one such repetitive peptide sequence (VPGVG) has been utilized in various bio-applications. To elucidate a mechanism for coacervation activity enhancement and to develop more potent coacervatable elastin-derived peptides, we synthesized two series of peptide analogs containing an aromatic amino acid, Trp or Tyr, in addition to Phe-containing analogs and tested their functional characteristics. Thus, position 1 of the hydrophobic pentapeptide repeat of elastin (X(1)P(2)G(3)V(4)G(5)) was substituted by Trp or Tyr. Eventually, we acquired a novel, short Trp-containing elastin-derived peptide analog (WPGVG)3 with potent coacervation ability. From the results obtained during this process, we determined the importance of aromaticity and hydrophobicity for the coacervation potency of elastin-derived peptide analogs. Generally, however, the production of long-chain synthetic polypeptides in quantities sufficient for commercial use remain cost-prohibitive. Therefore, the identification of (WPGVG)3, which is a 15-mer short peptide consisting simply of five natural amino acids and shows temperature-dependent self-assembly activity, might serve as a foundation for the development of various kinds of biomaterials. Copyright © 2015 European Peptide Society and John Wiley & Sons, Ltd.

  19. Site directed mutagenesis of amino acid residues at the active site of mouse aldehyde oxidase AOX1.

    Directory of Open Access Journals (Sweden)

    Silvia Schumann

    Full Text Available Mouse aldehyde oxidase (mAOX1 forms a homodimer and belongs to the xanthine oxidase family of molybdoenzymes which are characterized by an essential equatorial sulfur ligand coordinated to the molybdenum atom. In general, mammalian AOs are characterized by broad substrate specificity and an yet obscure physiological function. To define the physiological substrates and the enzymatic characteristics of mAOX1, we established a system for the heterologous expression of the enzyme in Escherichia coli. The recombinant protein showed spectral features and a range of substrate specificity similar to the native protein purified from mouse liver. The EPR data of recombinant mAOX1 were similar to those of AO from rabbit liver, but differed from the homologous xanthine oxidoreductase enzymes. Site-directed mutagenesis of amino acids Val806, Met884 and Glu1265 at the active site resulted in a drastic decrease in the oxidation of aldehydes with no increase in the oxidation of purine substrates. The double mutant V806E/M884R and the single mutant E1265Q were catalytically inactive enzymes regardless of the aldehyde or purine substrates tested. Our results show that only Glu1265 is essential for the catalytic activity by initiating the base-catalyzed mechanism of substrate oxidation. In addition, it is concluded that the substrate specificity of molybdo-flavoenzymes is more complex and not only defined by the three characterized amino acids in the active site.

  20. Effects of mutagenesis of aspartic acid residues in the putative phosphoribosyl diphosphate binding site of Escherichia coli phosphoribosyl diphosphate synthetase on metal ion specificity and ribose-5-phosphate binding

    DEFF Research Database (Denmark)

    Willemoës, Martin; Nilsson, Dan; Hove-Jensen, Bjarne

    1996-01-01

    The three conserved aspartic acid residues of the 5-phospho-d-ribosyl a-1-diphosphate binding site (213-GRDCVLVDDMIDTGGT-228) of Escherichia coli phosphoribosyl diphosphate synthetase were studied by analysis of the mutant enzymes D220E, D220F, D221A, D224A, and D224S. The mutant enzymes showed...... enzymes were dependent on the metal ion present, suggesting a function of the investigated aspartic acid residues both in the binding of ribose 5-phosphate, possibly via a divalent metal ion, and in the interaction with a divalent metal ion during catalysis....

  1. Amino acid sequence requirements in the hinge of human immunoglobulin A1 (IgA1) for cleavage by streptococcal IgA1 proteases

    DEFF Research Database (Denmark)

    Batten, MR; Senior, BW; Kilian, Mogens

    2003-01-01

    The amino acid sequence requirements in the hinge of human immunoglobulin A1 (IgA1) for cleavage by IgA1 proteases of different species of Streptococcus were investigated. Recombinant IgA1 antibodies were generated with point mutations at proline 227 and threonine 228, the residues lying on either...... side of the peptide bond at which all streptococcal IgA1 proteases cleave wild-type human IgA1. The amino acid substitutions produced no major effect upon the structure of the mutant IgA1 antibodies or their functional ability to bind to Fcalpha receptors. However, the substitutions had a substantial...... effect upon sensitivity to cleavage with some streptococcal IgA1 proteases, with, in some cases, a single point mutation rendering the antibody resistant to a particular IgA1 protease. This effect was least marked with the IgA1 protease from Streptococcus pneumoniae, which showed no absolute requirement...

  2. Minimal health impacts but detectable tissue residues after exposure of northern leopard frogs (Lithobates pipiens) to commercial naphthenic acids

    International Nuclear Information System (INIS)

    Hersikorn, B.; Young, R.; Fedorak, P.; Smits, J.

    2010-01-01

    This presentation reported on a study that examined whether naphthenic acids (NAs) are a toxic component in oil sands process-affected materials (OSPM). The study investigated the toxicity of commercial (Refined Merichem) NAs to native amphibians (northern leopard frogs) exposed to saline conditions comparable to those of reclaimed wetlands on oil sand leases. Gas chromatography-mass spectroscopy analysis showed that the exposure of frogs to NAs solutions for 28 days resulted in proportional NA concentrations in extracts of frog muscle tissue. Biological assays were performed to determine if the increasing exposure to NAs caused a proportional compromise in the health of test animals. The innate immune function, thyroid hormones, and hepatic detoxification enzyme induction did not differ in response to increased tissue concentrations of NAs. The commercial NAs were absorbed and deposited in muscle tissue. It was concluded that NAs play only a small, if any, role in the toxicity of OSPM to frogs.

  3. 78 FR 46265 - Complex Polymeric Polyhydroxy Acids; Exemption From the Requirement of a Tolerance

    Science.gov (United States)

    2013-07-31

    ... fresh and salt water environments as a result of decaying plant materials, and are used to condition... human risk. EPA considers the toxicity database to be complete and has identified no residual...

  4. Prostatic acid phosphatase is required for the antinociceptive effects of thiamine and benfotiamine.

    Science.gov (United States)

    Hurt, Julie K; Coleman, Jennifer L; Fitzpatrick, Brendan J; Taylor-Blake, Bonnie; Bridges, Arlene S; Vihko, Pirkko; Zylka, Mark J

    2012-01-01

    Thiamine (Vitamin B1) is an essential vitamin that must be obtained from the diet for proper neurological function. At higher doses, thiamine and benfotiamine (S-benzoylthiamine O-monophosphate, BT)-a phosphorylated derivative of thiamine-have antinociceptive effects in animals and humans, although how these compounds inhibit pain is unknown. Here, we found that Prostatic acid phosphatase (PAP, ACPP) can dephosphorylate BT in vitro, in dorsal root ganglia (DRG) neurons and in primary-afferent axon terminals in the dorsal spinal cord. The dephosphorylated product S-benzoylthiamine (S-BT) then decomposes to O-benzoylthiamine (O-BT) and to thiamine in a pH-dependent manner, independent of additional enzymes. This unique reaction mechanism reveals that BT only requires a phosphatase for conversion to thiamine. However, we found that the antinociceptive effects of BT, thiamine monophosphate (TMP) and thiamine-a compound that is not phosphorylated-were entirely dependent on PAP at the spinal level. Moreover, pharmacokinetic studies with wild-type and Pap(-/-) mice revealed that PAP is not required for the conversion of BT to thiamine in vivo. Taken together, our study highlights an obligatory role for PAP in the antinociceptive effects of thiamine and phosphorylated thiamine analogs, and suggests a novel phosphatase-independent function for PAP.

  5. Prostatic acid phosphatase is required for the antinociceptive effects of thiamine and benfotiamine.

    Directory of Open Access Journals (Sweden)

    Julie K Hurt

    Full Text Available Thiamine (Vitamin B1 is an essential vitamin that must be obtained from the diet for proper neurological function. At higher doses, thiamine and benfotiamine (S-benzoylthiamine O-monophosphate, BT-a phosphorylated derivative of thiamine-have antinociceptive effects in animals and humans, although how these compounds inhibit pain is unknown. Here, we found that Prostatic acid phosphatase (PAP, ACPP can dephosphorylate BT in vitro, in dorsal root ganglia (DRG neurons and in primary-afferent axon terminals in the dorsal spinal cord. The dephosphorylated product S-benzoylthiamine (S-BT then decomposes to O-benzoylthiamine (O-BT and to thiamine in a pH-dependent manner, independent of additional enzymes. This unique reaction mechanism reveals that BT only requires a phosphatase for conversion to thiamine. However, we found that the antinociceptive effects of BT, thiamine monophosphate (TMP and thiamine-a compound that is not phosphorylated-were entirely dependent on PAP at the spinal level. Moreover, pharmacokinetic studies with wild-type and Pap(-/- mice revealed that PAP is not required for the conversion of BT to thiamine in vivo. Taken together, our study highlights an obligatory role for PAP in the antinociceptive effects of thiamine and phosphorylated thiamine analogs, and suggests a novel phosphatase-independent function for PAP.

  6. Contribution of post-harvest agricultural paddy residue fires in the N.W. Indo-Gangetic Plain to ambient carcinogenic benzenoids, toxic isocyanic acid and carbon monoxide.

    Science.gov (United States)

    Chandra, B P; Sinha, Vinayak

    2016-03-01

    In the north west Indo-Gangetic Plain (N.W.IGP), large scale post-harvest paddy residue fires occur every year during the months of October-November. This anthropogenic perturbation causes contamination of the atmospheric environment with adverse impacts on regional air quality posing health risks for the population exposed to high concentrations of carcinogens such as benzene and toxic VOCs such as isocyanic acid. These gases and carbon monoxide are known to be emitted from biomass fires along with acetonitrile. Yet no long-term in-situ measurements quantifying the impact of this activity have been carried out in the N.W. IGP. Using high quality continuous online in-situ measurements of these gases at a strategic downwind site over a three year period from 2012 to 2014, we demonstrate the strong impact of this anthropogenic emission activity on ambient concentrations of these gases. In contrast to the pre-paddy harvest period, excellent correlation of benzenoids, isocyanic acid and CO with acetonitrile (a biomass burning chemical tracer); (r≥0.82) and distinct VOC/acetonitrile emission ratios were observed for the post-paddy harvest period which was also characterized by high ambient concentrations of these species. The average concentrations of acetonitrile (1.62±0.18ppb), benzene (2.51±0.28ppb), toluene (3.72±0.41ppb), C8-aromatics (2.88±0.30ppb), C9-aromatics (1.55±0.19ppb) and CO (552±113ppb) in the post-paddy harvest periods were about 1.5 times higher than the annual average concentrations. For isocyanic acid, a compound with both primary and secondary sources, the concentration in the post-paddy harvest period was 0.97±0.17ppb. The annual average concentrations of benzene, a class A carcinogen, exceeded the annual exposure limit of 1.6ppb at NTP mandated by the National Ambient Air Quality Standard of India (NAAQS). We show that mitigating the post-harvest paddy residue fires can lower the annual average concentration of benzene and ensure

  7. RNASEK is required for internalization of diverse acid-dependent viruses.

    Science.gov (United States)

    Hackett, Brent A; Yasunaga, Ari; Panda, Debasis; Tartell, Michael A; Hopkins, Kaycie C; Hensley, Scott E; Cherry, Sara

    2015-06-23

    Viruses must gain entry into cells to establish infection. In general, viruses enter either at the plasma membrane or from intracellular endosomal compartments. Viruses that use endosomal pathways are dependent on the cellular factors that control this process; however, these genes have proven to be essential for endogenous cargo uptake, and thus are of limited value for therapeutic intervention. The identification of genes that are selectively required for viral uptake would make appealing drug targets, as their inhibition would block an early step in the life cycle of diverse viruses. At this time, we lack pan-antiviral therapeutics, in part because of our lack of knowledge of such cellular factors. RNAi screening has begun to reveal previously unknown genes that play roles in viral infection. We identified dRNASEK in two genome-wide RNAi screens performed in Drosophila cells against West Nile and Rift Valley Fever viruses. Here we found that ribonuclease kappa (RNASEK) is essential for the infection of human cells by divergent and unrelated positive- and negative-strand-enveloped viruses from the Flaviviridae, Togaviridae, Bunyaviridae, and Orthomyxoviridae families that all enter cells from endosomal compartments. In contrast, RNASEK was dispensable for viruses, including parainfluenza virus 5 and Coxsackie B virus, that enter at the plasma membrane. RNASEK is dispensable for attachment but is required for uptake of these acid-dependent viruses. Furthermore, this requirement appears specific, as general endocytic uptake of transferrin is unaffected in RNASEK-depleted cells. Therefore, RNASEK is a potential host cell Achilles' heel for viral infection.

  8. Removal of acidic interferences in multi-pesticides residue analysis of fruits using modified magnetic nanoparticles prior to determination via ultra-HPLC-MS/MS

    International Nuclear Information System (INIS)

    Qi, Peipei; Wang, Zhiwei; Yang, Guiling; Wang, Xinquan; Shang, Chunqing; Xu, Hao; Wang, Xiangyun; Zhang, Hu; Wang, Qiang

    2015-01-01

    The authors describe magnetite (Fe 3 O 4 ) nanoparticles modified with 3-(N,N-diethylamino) propyltrimethoxysilane (Fe 3 O 4 -PSA NPs) for use as a sorbent for dispersive solid phase extraction of pesticide residues. The Fe 3 O 4 -PSA NPs were prepared by silanizing Fe 3 O 4 NPs and modifying them with 3-(N,N-diethylamino) propyltrimethoxysilane. Field-emission scanning electron microscopy, FTIR and zeta potential measurements were employed to characterize the modified NPs. They were then used as an adsorbent to remove acidic interferences (such as malic acid and succinic acid), which are major interferences in LC-MS/MS analysis in causing ion suppression in the MS spectra of pesticides. In addition, graphitized carbon black (GCB) was used as an adsorbent to eliminate interferences by pigments. The use of Fe 3 O 4 -PSA NPs can replace time-consuming centrifugation as used in the so-called QuEChERS (quick, easy, cheap, effective, rugged and safe) method. This improvement is particularly significant in high-throughput analysis. Following the optimization of the quantities of Fe 3 O 4 -PSA NPs and GCB, the method was applied to the determination of 56 pesticides in (spiked) fruits (apple, kiwi, orange and pear) by ultra-HPLC-MS/MS. The analytical ranges typically extend from 1 to 200 ng∙mL −1 , and recoveries range from 60.2 to 130 % at different concentrations of all four kinds of fruits. The LOQs for the pesticides are 10 ng∙kg −1 , which makes the method a viable tool for pesticide monitoring in fruits. (author)

  9. Aging impacts of low molecular weight organic acids (LMWOAs) on furfural production residue-derived biochars: Porosity, functional properties, and inorganic minerals.

    Science.gov (United States)

    Liu, Guocheng; Chen, Lei; Jiang, Zhixiang; Zheng, Hao; Dai, Yanhui; Luo, Xianxiang; Wang, Zhenyu

    2017-12-31

    The aging of biochar by low molecular weight organic acids (LMWOAs), which are typical root-derived exudates, is not well understood. Three LMWOAs (ethanoic, malic, and citric acids) were employed to investigate their aging impacts on the biochars from furfural production residues at 300-600°C (BC300-600). The LMWOAs created abundant macropores in BC300, whereas they significantly increased the mesoporosity and surface area of BC600 by 13.5-27.0% and 44.6-61.5%, respectively. After LMWOA aging, the content of C and H of the biochars increased from 51.3-60.2% and 1.87-3.45% to 56.8-69.9% and 2.06-4.45%, respectively, but the O content decreased from 13.8-24.8% to 7.82-19.4% (except BC300). For carbon fraction in the biochars, the LMWOAs barely altered the bulk and surface functional properties during short-term aging. The LMWOAs facilitated the dissolution of minerals (e.g., K 2 Mg(PO 3 ) 4 , AlPO 4 , and Pb 2 P 2 O 7 ) and correspondingly promoted the release of not only plant nutrients (K + , Ca 2+ , Mg 2+ , Fe 3+ , PO 4 3- , and SO 4 2- ) but also toxic metals (Al 3+ and Pb 2+ ). This research provided systematic insights on the responses of biochar properties to LMWOAs and presented direct evidence for acid activation of inorganic minerals in the biochars by LMWOAs, which could enhance the understanding of environmental behaviors of biochars in rhizosphere soils. Copyright © 2017 Elsevier B.V. All rights reserved.

  10. Biodegradation and speciation of residual SS-ethylenediaminedisuccinic acid (EDDS) in soil solution left after soil washing.

    Science.gov (United States)

    Tandy, Susan; Ammann, Adrian; Schulin, Rainer; Nowack, Bernd

    2006-07-01

    This paper aims to investigate the degradation and speciation of EDDS-complexes (SS-ethylenediaminedisuccinic acid) in soil following soil washing. The changes in soil solution metal and EDDS concentrations were investigated for three polluted soils. EDDS was degraded after a lag phase of 7-11 days with a half-life of 4.18-5.60 days. No influence of EDDS-speciation on the reaction was observed. The decrease in EDDS resulted in a corresponding decrease in solubilized metals. Changes in EDDS speciation can be related to (1) initial composition of the soil, (2) temporarily anoxic conditions in the soil slurry after soil washing, (3) exchange of EDDS complexes with Cu even in soils without elevated Cu and (4) formation of NiEDDS. Dissolved organic matter is important for metal speciation at low EDDS concentrations. Our results show that even in polluted soils EDDS is degraded from a level of several hundred micromoles to below 1 microM within 50 days.

  11. Better preservation of residual renal function in peritoneal dialysis patients treated with a low-protein diet supplemented with keto acids: a prospective, randomized trial.

    Science.gov (United States)

    Jiang, Na; Qian, Jiaqi; Sun, Weilan; Lin, Aiwu; Cao, Liou; Wang, Qin; Ni, Zhaohui; Wan, Yanping; Linholm, Bengt; Axelsson, Jonas; Yao, Qiang

    2009-08-01

    While a low-protein diet may preserve residual renal function (RRF) in chronic kidney disease (CKD) patients before the start of dialysis, a high-protein intake is usually recommended in dialysis patients to prevent protein-energy wasting. Keto acids, which were often recommended to pre-dialysis CKD patients treated with a low-protein diet, had also been reported to be associated with both RRF and nutrition maintenance. We conducted a randomized trial to test whether a low-protein diet with or without keto acids would be safe and associated with a preserved RRF during peritoneal dialysis (PD). To assess the safety of low protein, we first conducted a nitrogen balance study in 34 incident PD patients randomized to receive in-centre diets containing 1.2, 0.9 or 0.6 g of protein/kg ideal body weight (IBW)/day for 10 days. Second, 60 stable PD patients [RRF 4.04 +/- 2.30 ml/ min/1.73 m(2), urine output 1226 +/- 449 ml/day, aged 53.6 +/- 12.8 years, PD duration 8.8 (1.5-17.8) months] were randomized to receive either a low- (LP: 0.6-0.8 g/kg IBW/day), keto acid-supplemented low- (sLP: 0.6-0.8 g/kg IBW/day with 0.12 g/kg IBW/day of keto acids) or high-protein (HP: 1.0-1.2 g/kg IBW/day) diet. The groups were followed for 1 year and RRF as well as nutritional status was evaluated serially. A neutral or positive nitrogen balance was achieved in all three groups. RRF remained stable in group sLP (3.84 +/- 2.17 to 3.39 +/- 3.23 ml/min/1.73 m(2), P = ns) while it decreased in group LP (4.02 +/- 2.49 to 2.29 +/- 1.72 ml/min/1.73 m(2), P diet containing 0.6-0.8 g of protein/kg IBW/day is safe and, when combined with keto acids, is associated with an improved preservation of RRF in relatively new PD patients without significant malnutrition or inflammation.

  12. Docosahexaenoic acid (DHA, essentiality and requirements: why and how to provide supplementation

    Directory of Open Access Journals (Sweden)

    Nieto, Susana

    2006-06-01

    Full Text Available Lipids comprize from 50-60% of the structural matter of the brain and docosahexaenoic acid (C22:6, DHA is the most  important omega-3 long-chain polyunsaturated fatty acid in the brain phospholipids comprizing 25% of the total fatty acids of the grey matter. The majority of the DHA present in the human brain is incorporated during the brain growth spurt which starts at week 26 of gestation and imposes a high demand for the fatty acid until about 2 years of age. DHA is required during brain development when neuronal and glial differentiation and migration, and active myelination and synaptogenesis take place. The fatty acid must be incorporated into the brain lipids as preformed DHA because less than 5% of its precursor (alpha linolenic acid, LNA is converted to DHA. The human foetus has a limited ability to synthesize DHA from LNA, and therefore it must be largely supplied from maternal sources. Maternal DHA available for foetal nutrition can be provided from three main sources: adipose tissue, which is the main reservoir for the fatty acid; through biosynthesis from the precursor LNA, which occurs mainly in the liver; and as preformed DHA from dietary sources. In the postnatal period DHA is provided by the mother to the newborn through milk secretion. Western nutrition provides low LNA and DHA and Expert Nutrition Committees suggest that mothers should receive DHA supplementation during pregnancy and lactation. At present DHA supplementation can be provided from different sources: as purified free DHA, as an ethyl ester derivative, extracted from single-cell algae oils, from egg yolk phospholipids, or in the form of sn-2 DHA monoacylglycerol. In this review we revise and discuss the evidence of DHA requirements for the newborn, the need for maternal supplementation during pregnancy and nursing, and the alternatives at present for providing DHA supplementation.Los lípidos comprenden entre el 50-60% de la estructura del cerebro, y el

  13. Effect of tranexamic acid on intraoperative blood loss and transfusion requirements in patients undergoing excision of intracranial meningioma.

    Science.gov (United States)

    Hooda, Bhavna; Chouhan, Rajendra Singh; Rath, Girija Prasad; Bithal, Parmod Kumar; Suri, Ashish; Lamsal, Ritesh

    2017-07-01

    Surgical excision of meningioma is often complicated by significant blood loss requiring blood transfusion with its attendant risks. Although tranexamic acid is used to reduce perioperative blood loss, its blood conservation effect is uncertain in neurosurgery. Sixty adults undergoing elective craniotomy for meningioma excision were randomized to receive either tranexamic acid or placebo, initiated prior to skin incision. Patients in the tranexamic acid group received intravenous bolus of 20mg/kg over 20min followed by an infusion of 1mg/kg/h till the conclusion of surgery. Intraoperative blood loss, transfusion requirements and estimation of surgical hemostasis using a 5-grade scale were noted. Postoperatively, the extent of tumor excision on CT scan and complications were observed. Demographics, tumor characteristics, amount of fluid infusion, and duration of surgery and anesthesia were comparable between the two groups. The amount of blood loss was significantly less in tranexamic acid group compared to placebo (830mlvs 1124ml; p=0.03). The transfusion requirement was less in tranexamic acid group (p>0.05). The patients in tranexamic acid group fared better on a 5-grade surgical hemostasis scale with more patients showing good hemostasis (p=0.007). There were no significant differences between the groups with regards to extent of tumor removal, perioperative complications, hospital stay or neurologic outcome. To conclude, administration of tranexamic acid significantly reduced blood loss in patients undergoing excision of meningioma. Fewer patients in the tranexamic acid group received blood transfusions. Surgical field hemostasis was better achieved in patients who received tranexamic acid. Copyright © 2017 Elsevier Ltd. All rights reserved.

  14. Identification of residues within the African swine fever virus DP71L protein required for dephosphorylation of translation initiation factor eIF2α and inhibiting activation of pro-apoptotic CHOP

    Energy Technology Data Exchange (ETDEWEB)

    Barber, Claire; Netherton, Chris; Goatley, Lynnette [The Pirbright Institute, Ash Road, Pirbright, Woking, Surrey GU24 0NF (United Kingdom); Moon, Alice; Goodbourn, Steve [Institute for Infection and Immunity, St. George' s, University of London, London SW17 0RE (United Kingdom); Dixon, Linda, E-mail: linda.dixon@pirbright.ac.uk [The Pirbright Institute, Ash Road, Pirbright, Woking, Surrey GU24 0NF (United Kingdom)

    2017-04-15

    The African swine fever virus DP71L protein recruits protein phosphatase 1 (PP1) to dephosphorylate the translation initiation factor 2α (eIF2α) and avoid shut-off of global protein synthesis and downstream activation of the pro-apoptotic factor CHOP. Residues V16 and F18A were critical for binding of DP71L to PP1. Mutation of this PP1 binding motif or deletion of residues between 52 and 66 reduced the ability of DP71L to cause dephosphorylation of eIF2α and inhibit CHOP induction. The residues LSAVL, between 57 and 61, were also required. PP1 was co-precipitated with wild type DP71L and the mutant lacking residues 52- 66 or the LSAVL motif, but not with the PP1 binding motif mutant. The residues in the LSAVL motif play a critical role in DP71L function but do not interfere with binding to PP1. Instead we propose these residues are important for DP71L binding to eIF2α. - Highlights: •The African swine fever virus DP71L protein recruits protein phosphatase 1 (PP1) to dephosphorylate translation initiation factor eIF2α (eIF2α). •The residues V{sup 16}, F{sup 18} of DP71L are required for binding to the α, β and γ isoforms of PP1 and for DP71L function. •The sequence LSAVL downstream from the PP1 binding site (residues 57–61) are also important for DP71L function. •DP71L mutants of the LSAVL sequence retain ability to co-precipitate with PP1 showing these sequences have a different role to PP1 binding.

  15. Disinfection of wastewater by hydrogen peroxide or peracetic acid: development of procedures for measurement of residual disinfectant and application to a physicochemically treated municipal effluent.

    Science.gov (United States)

    Wagner, Monika; Brumelis, Daina; Gehr, Ronald

    2002-01-01

    The Montreal Urban Community Wastewater Treatment Plant (MUCWTP) located in Montreal. Quebec, Canada, uses physicochemical treatment processes prior to discharging wastewater into the St. Lawrence River via an outfall tunnel of 2 hours retention time. Although chlorination facilities exist, they are not being used, and the MUCWTP is seeking alternative methods for disinfection to achieve a 2- to 3-log fecal coliform reduction. Liquid chemical disinfectants were attractive options because of their low capital costs. This led to an investigation of the feasibility of using hydrogen peroxide or peracetic acid. A method for measuring peroxycompounds (hydrogen peroxide or peracetic acid plus hydrogen peroxide) was developed using the peroxidase-based oxidation of 2,2'-azino-bis(3-ethylbenz-thiazoline-6-sulfuric acid) diammonium salt (ABTS) with hydrogen peroxide. The validity of the method was confirmed using effluent from the MUCWTP. Recovery was higher than 90% for peracetic acid levels as low as 1.0 mg/L. Quenching of hydrogen peroxide was achieved with 50-mg/L catalase; quenching of peracetic acid was achieved with 100 mg/L of sodium thiosulfate, followed by 50 mg/L of catalase. Batch disinfection tests were conducted on MUCWTP effluent. Hydrogen peroxide and peracetic acid in wastewater over time could be modeled as a second-order decay, with the decay "constant" being a function of the initial concentration of peroxycompounds. This function was the same for both hydrogen peroxide and peracetic acid, possibly indicating similar decomposition pathways in wastewater matrices. Disinfection was modeled using a modified Hom equation. Required doses of hydrogen peroxide to reach the target fecal coliform levels ranged from 106 to 285 mg/L, with the higher doses occurring when ferric chloride instead of alum was used as the coagulant. Hence, hydrogen peroxide was infeasible as a disinfectant for this application. On the other hand, the peracetic acid dose needed to

  16. Mass spectrometric differentiation of linear peptides composed of L-amino acids from isomers containing one D-amino acid residue.

    Science.gov (United States)

    Serafin, Scott V; Maranan, Rhonda; Zhang, Kangling; Morton, Thomas Hellman

    2005-09-01

    MS/MS of electrosprayed ions is shown to have the capacity to discriminate between peptides that differ by configuration about their alpha-carbons. It is not necessary for the peptides to possess tertiary structures that are affected by stereochemistry, since five epimers of the pentapeptide, H2N-Gly-Leu-Ser-Phe-Ala-OH (GLSFA) all display different collisionally activated dissociation (CAD) patterns of their protonated parent ions. The figure of merit, r, is a ratio of ratios of fragment ion abundances between stereoisomers, where r = 1 corresponds to no stereochemical effect. Values of r as high as 3.8 are seen for diastereomer pairs. Stereochemical effects are also seen for the diprotonated dodecapeptide H2N-Leu-Val-Phe-Phe-Ala-Glu-Asp-Val-Gly-Ser-Asn-Lys-OH (LVFFAEDVGSNK), a tryptic fragment from the amyloid beta-protein. Triply charged complexes of the protonated dodecapeptide with cobalt(II) ions undergo CAD at lower collision energies than do doubly protonated LVFFAEDVGSNK ions. Statistically significant (p < 0.01) differences between the all-L-dodecapeptide and the ones containing a d-serine or a D-aspartic acid are observed.

  17. The Arabidopsis Vacuolar Sorting Receptor1 Is Required for Osmotic Stress-Induced Abscisic Acid Biosynthesis

    KAUST Repository

    Wang, Zhen-Yu

    2014-11-21

    Osmotic stress activates the biosynthesis of the phytohormone abscisic acid (ABA) through a pathway that is rate limited by the carotenoid cleavage enzyme 9-cis-epoxycarotenoid dioxygenase (NCED). To understand the signal transduction mechanism underlying the activation of ABA biosynthesis, we performed a forward genetic screen to isolate mutants defective in osmotic stress regulation of the NCED3 gene. Here, we identified the Arabidopsis (Arabidopsis thaliana) Vacuolar Sorting Receptor1 (VSR1) as a unique regulator of ABA biosynthesis. The vsr1 mutant not only shows increased sensitivity to osmotic stress, but also is defective in the feedback regulation of ABA biosynthesis by ABA. Further analysis revealed that vacuolar trafficking mediated by VSR1 is required for osmotic stress-responsive ABA biosynthesis and osmotic stress tolerance. Moreover, under osmotic stress conditions, the membrane potential, calcium flux, and vacuolar pH changes in the vsr1 mutant differ from those in the wild type. Given that manipulation of the intracellular pH is sufficient to modulate the expression of ABA biosynthesis genes, including NCED3, and ABA accumulation, we propose that intracellular pH changes caused by osmotic stress may play a signaling role in regulating ABA biosynthesis and that this regulation is dependent on functional VSR1.

  18. The Arabidopsis Vacuolar Sorting Receptor1 Is Required for Osmotic Stress-Induced Abscisic Acid Biosynthesis

    KAUST Repository

    Wang, Zhen-Yu; Gehring, Christoph A; Zhu, Jianhua; Li, Feng-Min; Zhu, Jian-Kang; Xiong, Liming

    2014-01-01

    Osmotic stress activates the biosynthesis of the phytohormone abscisic acid (ABA) through a pathway that is rate limited by the carotenoid cleavage enzyme 9-cis-epoxycarotenoid dioxygenase (NCED). To understand the signal transduction mechanism underlying the activation of ABA biosynthesis, we performed a forward genetic screen to isolate mutants defective in osmotic stress regulation of the NCED3 gene. Here, we identified the Arabidopsis (Arabidopsis thaliana) Vacuolar Sorting Receptor1 (VSR1) as a unique regulator of ABA biosynthesis. The vsr1 mutant not only shows increased sensitivity to osmotic stress, but also is defective in the feedback regulation of ABA biosynthesis by ABA. Further analysis revealed that vacuolar trafficking mediated by VSR1 is required for osmotic stress-responsive ABA biosynthesis and osmotic stress tolerance. Moreover, under osmotic stress conditions, the membrane potential, calcium flux, and vacuolar pH changes in the vsr1 mutant differ from those in the wild type. Given that manipulation of the intracellular pH is sufficient to modulate the expression of ABA biosynthesis genes, including NCED3, and ABA accumulation, we propose that intracellular pH changes caused by osmotic stress may play a signaling role in regulating ABA biosynthesis and that this regulation is dependent on functional VSR1.

  19. Genome-wide identification of Saccharomyces cerevisiae genes required for tolerance to acetic acid

    Directory of Open Access Journals (Sweden)

    Sá-Correia Isabel

    2010-10-01

    Full Text Available Abstract Background Acetic acid is a byproduct of Saccharomyces cerevisiae alcoholic fermentation. Together with high concentrations of ethanol and other toxic metabolites, acetic acid may contribute to fermentation arrest and reduced ethanol productivity. This weak acid is also a present in lignocellulosic hydrolysates, a highly interesting non-feedstock substrate in industrial biotechnology. Therefore, the better understanding of the molecular mechanisms underlying S. cerevisiae tolerance to acetic acid is essential for the rational selection of optimal fermentation conditions and the engineering of more robust industrial strains to be used in processes in which yeast is explored as cell factory. Results The yeast genes conferring protection against acetic acid were identified in this study at a genome-wide scale, based on the screening of the EUROSCARF haploid mutant collection for susceptibility phenotypes to this weak acid (concentrations in the range 70-110 mM, at pH 4.5. Approximately 650 determinants of tolerance to acetic acid were identified. Clustering of these acetic acid-resistance genes based on their biological function indicated an enrichment of genes involved in transcription, internal pH homeostasis, carbohydrate metabolism, cell wall assembly, biogenesis of mitochondria, ribosome and vacuole, and in the sensing, signalling and uptake of various nutrients in particular iron, potassium, glucose and amino acids. A correlation between increased resistance to acetic acid and the level of potassium in the growth medium was found. The activation of the Snf1p signalling pathway, involved in yeast response to glucose starvation, is demonstrated to occur in response to acetic acid stress but no evidence was obtained supporting the acetic acid-induced inhibition of glucose uptake. Conclusions Approximately 490 of the 650 determinants of tolerance to acetic acid identified in this work are implicated, for the first time, in tolerance to

  20. MMS sensitivity of all amino acid-requiring mutants in aspergillus and its suppression by mutations in a single gene.

    Science.gov (United States)

    Käfer, E

    1987-04-01

    All available amino acid-requiring mutants of Aspergillus nidulans were found to be hypersensitive to MMS (methyl methanesulfonate) to various degrees. On MMS media, secondary mutations could be selected which suppress this MMS sensitivity but do not affect the requirement. Many such mutations were analyzed and found to be alleles of one gene, smsA (= suppressor of MMS sensitivity), which mapped distal on the right arm of chromosome V. This gene is more likely to be involved in general regulation of amino acid biosynthesis than MMS uptake, since a variety of pathway interactions were clearly modified by smsA suppressors in the absence of MMS.

  1. Residual stresses

    International Nuclear Information System (INIS)

    Sahotra, I.M.

    2006-01-01

    The principal effect of unloading a material strained into the plastic range is to create a permanent set (plastic deformation), which if restricted somehow, gives rise to a system of self-balancing within the same member or reaction balanced by other members of the structure., known as residual stresses. These stresses stay there as locked-in stresses, in the body or a part of it in the absence of any external loading. Residual stresses are induced during hot-rolling and welding differential cooling, cold-forming and extruding: cold straightening and spot heating, fabrication and forced fitting of components constraining the structure to a particular geometry. The areas which cool more quickly develop residual compressive stresses, while the slower cooling areas develop residual tensile stresses, and a self-balancing or reaction balanced system of residual stresses is formed. The phenomenon of residual stresses is the most challenging in its application in surface modification techniques determining endurance mechanism against fracture and fatigue failures. This paper discusses the mechanism of residual stresses, that how the residual stresses are fanned and what their behavior is under the action of external forces. Such as in the case of a circular bar under limit torque, rectangular beam under limt moment, reclaiming of shafts welds and peening etc. (author)

  2. Measurement of {sup 1}H-{sup 15}N and {sup 1}H-{sup 13}C residual dipolar couplings in nucleic acids from TROSY intensities

    Energy Technology Data Exchange (ETDEWEB)

    Ying Jinfa [National Institutes of Health, Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases (United States); Wang Jinbu [National Cancer Institute, National Institutes of Health, Structural Biophysics Laboratory (United States); Grishaev, Alex [National Institutes of Health, Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases (United States); Yu Ping; Wang Yunxing [National Cancer Institute, National Institutes of Health, Structural Biophysics Laboratory (United States); Bax, Ad, E-mail: bax@nih.gov [National Institutes of Health, Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases (United States)

    2011-09-15

    Analogous to the recently introduced ARTSY method for measurement of one-bond {sup 1}H-{sup 15}N residual dipolar couplings (RDCs) in large perdeuterated proteins, we introduce methods for measurement of base {sup 13}C-{sup 1}H and {sup 15}N-{sup 1}H RDCs in protonated nucleic acids. Measurements are based on quantitative analysis of intensities in {sup 1}H-{sup 15}N and {sup 13}C-{sup 1}H TROSY-HSQC spectra, and are illustrated for a 71-nucleotide adenine riboswitch. Results compare favorably with those of conventional frequency-based measurements in terms of completeness and convenience of use. The ARTSY method derives the size of the coupling from the ratio of intensities observed in two TROSY-HSQC spectra recorded with different dephasing delays, thereby minimizing potential resonance overlap problems. Precision of the RDC measurements is limited by the signal-to-noise ratio, S/N, achievable in the 2D TROSY-HSQC reference spectrum, and is approximately given by 30/(S/N) Hz for {sup 15}N-{sup 1}H and 65/(S/N) Hz for {sup 13}C-{sup 1}H. The signal-to-noise ratio of both {sup 1}H-{sup 15}N and {sup 1}H-{sup 13}C spectra greatly benefits when water magnetization during the experiments is not perturbed, such that rapid magnetization transfer from bulk water to the nucleic acid, mediated by rapid amino and hydroxyl hydrogen exchange coupled with {sup 1}H-{sup 1}H NOE transfer, allows for fast repetition of the experiment. RDCs in the mutated helix 1 of the riboswitch are compatible with nucleotide-specifically modeled, idealized A-form geometry and a static orientation relative to the helix 2/3 pair, which differs by ca 6 Degree-Sign relative to the X-ray structure of the native riboswitch.

  3. 40 CFR 180.1159 - Pelargonic acid; exemption from the requirement of tolerances.

    Science.gov (United States)

    2010-07-01

    ..., vats, fillers, evaporators, pasteurizers and aseptic equipment in restaurants, food service operations, dairies, breweries, wineries, beverage and food processing plants. [62 FR 28364, May 23, 1997, as amended... (CONTINUED) PESTICIDE PROGRAMS TOLERANCES AND EXEMPTIONS FOR PESTICIDE CHEMICAL RESIDUES IN FOOD Exemptions...

  4. 77 FR 68686 - Xylenesulfonic Acid, Sodium Salt; Exemption From the Requirement of a Tolerance

    Science.gov (United States)

    2012-11-16

    ... of subchronic study data for chronic exposure assessment. The rational for this decision is provided... sanitizing solutions would exceed 500 ppm. B. International Residue Limits In making its tolerance decisions... compounded by EPA's decision to assume a worst case scenario that all food that an individual consumes will...

  5. Saturated very long chain fatty acids are required for the production of infectious human cytomegalovirus progeny.

    Directory of Open Access Journals (Sweden)

    Emre Koyuncu

    Full Text Available Human cytomegalovirus hijacks host cell metabolism, increasing the flux of carbon from glucose to malonyl-CoA, the committed precursor to fatty acid synthesis and elongation. Inhibition of acetyl-CoA carboxylase blocks the production of progeny virus. To probe further the role of fatty acid metabolism during infection, we performed an siRNA screen to identify host cell metabolic enzymes needed for the production of infectious cytomegalovirus progeny. The screen predicted that multiple long chain acyl-CoA synthetases and fatty acid elongases are needed during infection, and the levels of RNAs encoding several of these enzymes were upregulated by the virus. Roles for acyl-CoA synthetases and elongases during infection were confirmed by using small molecule antagonists. Consistent with a role for these enzymes, mass spectrometry-based fatty acid analysis with ¹³C-labeling revealed that malonyl-CoA is consumed by elongases to produce very long chain fatty acids, generating an approximately 8-fold increase in C26-C34 fatty acid tails in infected cells. The virion envelope was yet further enriched in C26-C34 saturated fatty acids, and elongase inhibitors caused the production of virions with lower levels of these fatty acids and markedly reduced infectivity. These results reveal a dependence of cytomegalovirus on very long chain fatty acid metabolism.

  6. Evaluation of soluble fraction and enzymatic residual fraction of dilute dry acid, ethylenediamine, and steam explosion pretreated corn stover on the enzymatic hydrolysis of cellulose.

    Science.gov (United States)

    Qin, Lei; Liu, Li; Li, Wen-Chao; Zhu, Jia-Qing; Li, Bing-Zhi; Yuan, Ying-Jin

    2016-06-01

    This study is aimed to examine the inhibition of soluble fraction (SF) and enzymatic residual fraction (ERF) in dry dilute acid (DDA), ethylenediamine (EDA) and steam explosion (SE) pretreated corn stover (CS) on the enzymatic digestibility of cellulose. SF of DDA, EDA and SE pretreated CS has high xylose, soluble lignin and xylo-oligomer content, respectively. SF of EDA pretreated CS leads to the highest inhibition, followed by SE and DDA pretreated CS. Inhibition of ERF of DDA and SE pretreated CS is higher than that of EDA pretreated CS. The inhibition degree (A0/A) of SF is 1.76 and 1.21 times to that of ERF for EDA and SE pretreated CS, respectively. The inhibition degree of ERF is 1.05 times to that of SF in DDA pretreated CS. The quantitative analysis shows that SF of EDA pretreated CS, SF and ERF of SE pretreated CS cause significant inhibition during enzymatic hydrolysis. Copyright © 2016 Elsevier Ltd. All rights reserved.

  7. Green and sustainable succinic acid production from crude glycerol by engineered Yarrowia lipolytica via agricultural residue based in situ fibrous bed bioreactor.

    Science.gov (United States)

    Li, Chong; Gao, Shi; Yang, Xiaofeng; Lin, Carol Sze Ki

    2018-02-01

    In situ fibrous bed bioreactor (isFBB) for efficient succinic acid (SA) production by Yarrowia lipolytica was firstly developed in our former study. In this study, agricultural residues including wheat straw, corn stalk and sugarcane bagasse were investigated for the improvement of isFBB, and sugarcane bagasse was demonstrated to be the best immobilization material. With crude glycerol as the sole carbon source, optimization for isFBB batch fermentation was carried out. Under the optimal conditions of 20g sugarcane bagasse as immobilization material, 120gL -1 crude glycerol as carbon source and 4Lmin -1 of aeration rate, the resultant SA concentration was 53.6gL -1 with an average productivity of 1.45gL -1 h -1 and a SA yield of 0.45gg -1 . By feeding crude glycerol, SA titer up to 209.7gL -1 was obtained from fed batch fermentation, which was the highest value that ever reported. Copyright © 2017 Elsevier Ltd. All rights reserved.

  8. Proteomic investigation of protein profile changes and amino acid residue-level modification in cooked lamb longissimus thoracis et lumborum: The effect of roasting.

    Science.gov (United States)

    Yu, Tzer-Yang; Morton, James D; Clerens, Stefan; Dyer, Jolon M

    2016-09-01

    Protein modifications of meat cooked by typical dry-heat methods (e.g., roasting) are currently not well understood. The present study utilised a shotgun proteomic approach to examine the molecular-level effect of roasting on thin lamb longissimus thoracis et lumborum patties, in terms of changes to both the protein profile and amino acid residue side-chain modifications. Cooking caused aggregation of actin, myosin heavy chains and sarcoplasmic proteins. Longer roasting time resulted in significantly reduced protein extractability as well as protein truncation involving particularly a number of myofibrillar and sarcoplasmic proteins, e.g., 6-phosphofructokinase, beta-enolase, l-lactate dehydrogenase A chain, alpha-actinin-3, actin and possibly myosin heavy chains. Modifications that have potential influence on nutritional properties, including carboxyethyllysine and a potentially glucose-derived N-terminal Amadori compound, were observed in actin and myoglobin after roasting. This study provided new insights into molecular changes resulting from the dry-heat treatment of meat, such as commonly used in food preparation. Copyright © 2016 Elsevier Ltd. All rights reserved.

  9. Establishment of a novel immunoassay system for rapid detection of 2,4-dichlorophenoxyacetic acid residues based on magnetic-fluorescent probes

    Directory of Open Access Journals (Sweden)

    WANG Yuanfeng

    2014-12-01

    Full Text Available A novel immunoassay system based on magnetic-fluorescent probes was established to detect 2.4-dichlorophenoxyacetic acid (2,4-D residue in liquid system in food and agricultural products.The composites of anti-2,4-D antibody bound to Fe3O4@SiO2-NH2 was employed as the solid phase as well as magnetic probe.The composites composed of 2,4-D-OVA labeled with CdTe@SiO2-NH2 as the fluorescent probe was used to produce fluorescent signal.2,4-D and its fluorescent probe competed binding the antibody on the surface of the magnetic probe.The optimization of 2,4-D-OVA dosage,coupling PH and reaction time in preparing the fluorescent probe were investigated.It showed that in the synthesis of fluorescent probe 8.2 was the optimal pH,70 min was the optimal coupling time,500 μL amount of 2,4-D-OVA.The standard curve was obtained with the concentration of 2,4-D and the maximum fluorescence intensity.The detection limit of the assay was gotten and it was 3.55×10-8.One reaction step and one washing step were needed.The assay significantly shortened the testing time and amplified the detection signal compared with classic ELISA.

  10. Analysis of SAT Type Foot-And-Mouth Disease Virus Capsid Proteins and the Identification of Putative Amino Acid Residues Affecting Virus Stability

    Science.gov (United States)

    Maree, Francois F.; Blignaut, Belinda; de Beer, Tjaart A. P.; Rieder, Elizabeth

    2013-01-01

    Foot-and-mouth disease virus (FMDV) initiates infection by adhering to integrin receptors on target cells, followed by cell entry and disassembly of the virion through acidification within endosomes. Mild heating of the virions also leads to irreversible dissociation into pentamers, a characteristic linked to reduced vaccine efficacy. In this study, the structural stability of intra- and inter-serotype chimeric SAT2 and SAT3 virus particles to various conditions including low pH, mild temperatures or high ionic strength, was compared. Our results demonstrated that while both the SAT2 and SAT3 infectious capsids displayed different sensitivities in a series of low pH buffers, their stability profiles were comparable at high temperatures or high ionic strength conditions. Recombinant vSAT2 and intra-serotype chimeric viruses were used to map the amino acid differences in the capsid proteins of viruses with disparate low pH stabilities. Four His residues at the inter-pentamer interface were identified that change protonation states at pH 6.0. Of these, the H145 of VP3 appears to be involved in interactions with A141 in VP3 and K63 in VP2, and may be involved in orientating H142 of VP3 for interaction at the inter-pentamer interfaces. PMID:23717387

  11. Analysis of SAT type foot-and-mouth disease virus capsid proteins and the identification of putative amino acid residues affecting virus stability.

    Directory of Open Access Journals (Sweden)

    Francois F Maree

    Full Text Available Foot-and-mouth disease virus (FMDV initiates infection by adhering to integrin receptors on target cells, followed by cell entry and disassembly of the virion through acidification within endosomes. Mild heating of the virions also leads to irreversible dissociation into pentamers, a characteristic linked to reduced vaccine efficacy. In this study, the structural stability of intra- and inter-serotype chimeric SAT2 and SAT3 virus particles to various conditions including low pH, mild temperatures or high ionic strength, was compared. Our results demonstrated that while both the SAT2 and SAT3 infectious capsids displayed different sensitivities in a series of low pH buffers, their stability profiles were comparable at high temperatures or high ionic strength conditions. Recombinant vSAT2 and intra-serotype chimeric viruses were used to map the amino acid differences in the capsid proteins of viruses with disparate low pH stabilities. Four His residues at the inter-pentamer interface were identified that change protonation states at pH 6.0. Of these, the H145 of VP3 appears to be involved in interactions with A141 in VP3 and K63 in VP2, and may be involved in orientating H142 of VP3 for interaction at the inter-pentamer interfaces.

  12. Co-production of bio-ethanol, xylonic acid and slow-release nitrogen fertilizer from low-cost straw pulping solid residue.

    Science.gov (United States)

    Huang, Chen; Ragauskas, Arthur J; Wu, Xinxing; Huang, Yang; Zhou, Xuelian; He, Juan; Huang, Caoxing; Lai, Chenhuan; Li, Xin; Yong, Qiang

    2018-02-01

    A novel bio-refinery sequence yielding varieties of co-products was developed using straw pulping solid residue. This process utilizes neutral sulfite pretreatment which under optimal conditions (160 °C and 3% (w/v) sulfite charge) provides 64.3% delignification while retaining 90% of cellulose and 67.3% of xylan. The pretreated solids exhibited excellent enzymatic digestibility, with saccharification yields of 86.9% and 81.1% for cellulose and xylan, respectively. After pretreatment, the process of semi-simultaneous saccharification and fermentation (S-SSF) and bio-catalysis was investigated. The results revealed that decreased ethanol yields were achieved when solid loading increased from 5% to 30%. An acceptable ethanol yield of 76.8% was obtained at 20% solid loading. After fermentation, bio-catalysis of xylose remaining in fermentation broth resulted in near 100% xylonic acid (XA) yield at varied solid loadings. To complete the co-product portfolio, oxidation ammoniation of the dissolved lignin successfully transformed it into biodegradable slow-release nitrogen fertilizer with excellent agricultural properties. Copyright © 2017 Elsevier Ltd. All rights reserved.

  13. Conditional RARα Knockout Mice Reveal Acute Requirement for Retinoic Acid and RARα in Homeostatic Plasticity

    Directory of Open Access Journals (Sweden)

    Federica eSarti

    2012-02-01

    Full Text Available All-trans retinoic acid (RA plays important roles in brain development through regulating gene transcription. Recently, a novel postdevelopmental role of RA in mature brain was proposed. Specifically, RA rapidly enhanced excitatory synaptic transmission independent of transcriptional regulation. RA synthesis was induced when excitatory synaptic transmission was chronically blocked, and RA then activated dendritic protein synthesis and synaptic insertion of homomeric GluA1 AMPA receptors, thereby compensating for the loss of neuronal activity in a homeostatic fashion. This action of RA was suggested to be mediated by its canonical receptor RARα but no genetic evidence was available. Thus, we here tested the fundamental requirement of RARα in homeostatic plasticity using conditional RARα knockout mice, and additionally performed a structure-function analysis of RARα. We show that acutely deleting RARα in neurons eliminated RA’s effect on excitatory synaptic transmission, and inhibited activity blockade-induced homeostatic synaptic plasticity. By expressing various RARα rescue constructs in RARα knockout neurons, we found that the DNA-binding domain of RARα was dispensable for its role in regulating synaptic strength, further supporting the notion that RA and RARα act in a non-transcriptional manner in this context. By contrast, the ligand-binding domain (LBD and the mRNA-binding domain (F-domain are both necessary and sufficient for the function of RARα in homeostatic plasticity. Furthermore, we found that homeostatic regulation performed by the LBD/F domains leads to insertion of calcium-permeable AMPA receptors. Our results confirm with unequivocal genetic approaches that RA and RARα perform essential non-transcriptional functions in regulating synaptic strength, and establish a functional link between the various domains of RARα and their involvement in regulating protein synthesis and excitatory synaptic transmission during

  14. Mms Sensitivity of All Amino Acid-Requiring Mutants in Aspergillus and Its Suppression by Mutations in a Single Gene

    OpenAIRE

    Käfer, Etta

    1987-01-01

    All available amino acid-requiring mutants of Aspergillus nidulans were found to be hypersensitive to MMS (methyl methanesulfonate) to various degrees. On MMS media, secondary mutations could be selected which suppress this MMS sensitivity but do not affect the requirement. Many such mutations were analyzed and found to be alleles of one gene, smsA (= suppressor of MMS sensitivity), which mapped distal on the right arm of chromosome V. This gene is more likely to be involved in general regula...

  15. Residual stresses

    International Nuclear Information System (INIS)

    Macherauch, E.

    1978-01-01

    Residual stresses are stresses which exist in a material without the influence of external powers and moments. They come into existence when the volume of a material constantly changes its form as a consequence of mechanical, thermal, and/or chemical processes and is hindered by neighbouring volumes. Bodies with residual stress are in mechanical balance. These residual stresses can be manifested by means of all mechanical interventions disturbing this balance. Acoustical, optical, radiological, and magnetical methods involving material changes caused by residual stress can also serve for determining residual stress. Residual stresses have an ambivalent character. In technical practice, they are feared and liked at the same time. They cause trouble because they can be the cause for unexpected behaviour of construction elements. They are feared since they can cause failure, in the worst case with catastrophical consequences. They are appreciated, on the other hand, because, in many cases, they can contribute to improvements of the material behaviour under certain circumstances. But they are especially liked for their giving convenient and (this is most important) mostly uncontrollable explanations. For only in very few cases we have enough knowledge and possibilities for the objective evaluation of residual stresses. (orig.) [de

  16. The dapE-encoded N-succinyl-L,L-diaminopimelic acid desuccinylase from Haemophilus influenzae contains two active-site histidine residues.

    Science.gov (United States)

    Gillner, Danuta M; Bienvenue, David L; Nocek, Boguslaw P; Joachimiak, Andrzej; Zachary, Vincentos; Bennett, Brian; Holz, Richard C

    2009-01-01

    The catalytic and structural properties of the H67A and H349A dapE-encoded N-succinyl-L,L-diaminopimelic acid desuccinylase (DapE) from Haemophilus influenzae were investigated. On the basis of sequence alignment with the carboxypeptidase from Pseudomonas sp. strain RS-16, both H67 and H349 were predicted to be Zn(II) ligands. The H67A DapE enzyme exhibited a decreased catalytic efficiency (180-fold) compared with wild-type (WT) DapE towards N-succinyldiaminopimelic acid. No catalytic activity was observed for H349A under the experimental conditions used. The electronic paramagnetic resonance (EPR) and electronic absorption data indicate that the Co(II) ion bound to H349A-DapE is analogous to that of WT DapE after the addition of a single Co(II) ion. The addition of 1 equiv of Co(II) to H67A DapE provides spectra that are very different from those of the first Co(II) binding site of the WT enzyme, but that are similar to those of the second binding site. The EPR and electronic absorption data, in conjunction with the kinetic data, are consistent with the assignment of H67 and H349 as active-site metal ligands for the DapE from H. influenzae. Furthermore, the data suggest that H67 is a ligand in the first metal binding site, while H349 resides in the second metal binding site. A three-dimensional homology structure of the DapE from H. influenzae was generated using the X-ray crystal structure of the DapE from Neisseria meningitidis as a template and superimposed on the structure of the aminopeptidase from Aeromonas proteolytica (AAP). This homology structure confirms the assignment of H67 and H349 as active-site ligands. The superimposition of the homology model of DapE with the dizinc(II) structure of AAP indicates that within 4.0 A of the Zn(II) binding sites of AAP all of the amino acid residues of DapE are nearly identical.

  17. Utilization of alimentary protein and amino acids in satisfying the nitrogen requirements of monogastric mammals

    International Nuclear Information System (INIS)

    Pion, R.; Arnal, M.

    1976-01-01

    The nitrogenous matter in the food of monogastric animals consists mainly of proteins, which are rapidly hydrolized in the intestinal tract when they have left the gastric reservoir. The digestive tube has several roles: it provides for hydrolysis of the food proteins and for a supply of endogenous nitrogen; it enables a certain digestive function to be performed by the intestinal flora and permits the transport of amino acids into the blood, selecting those which are needed for protein synthesis. The digestion products appear mainly in the form of free amino acids in the portal blood. A large proportion of these amino acids is taken up by the liver, so that intense protein synthesis takes place in the latter, coupled with a decrease in catabolism leading to a rhythmic increase in the liver content of proteins and RNA. The labile proteins retained are mainly enzymes, which catabolize the amino acids, and the liver is the site of the catabolism of most of the excess amino acids except those with chain branching. Alimentary deficiencies do not markedly reduce protein synthesis in this organ, since the rate of re-utilization of the amino acids is increased and the liver thus plays a regulatory role. The utilization of amino acids in muscle also follows a certain rhythm, partly connected with feeding, and under hormonal control. The muscle is the seat of catabolism of a large part of the branched chain amino acids, and like the liver it contributes to the energy utilization of amino acids. The rate of utilization of certain essential amino acids can be measured by metabolic criteria, including determination of blood and muscle concentrations and excretion of 14 CO 2 labels in the exhaled air or of 35 S labels in urine. (author)

  18. Residue-specific description of non-native transient structures in the ensemble of acid-denatured structures of the all-beta protein c-src SH3

    DEFF Research Database (Denmark)

    Rösner, Heike I; Poulsen, Flemming Martin

    2010-01-01

    -src loop to the third beta-strand, exhibited an apparent helicity of nearly 45%. Furthermore, the RT loop and the diverging turn appeared to adopt non-native-like helical conformations. Interestingly, none of the residues found in transient helical conformations exhibited significant varphi-values [Riddle......Secondary chemical shift analysis has been used to characterize the unfolded state of acid-denatured c-src SH3. Even though native c-src SH3 adopts an all-beta fold, we found evidence of transient helicity in regions corresponding to native loops. In particular, residues 40-46, connecting the n...

  19. Americium recovery from reduction residues

    Science.gov (United States)

    Conner, W.V.; Proctor, S.G.

    1973-12-25

    A process for separation and recovery of americium values from container or bomb'' reduction residues comprising dissolving the residues in a suitable acid, adjusting the hydrogen ion concentration to a desired level by adding a base, precipitating the americium as americium oxalate by adding oxalic acid, digesting the solution, separating the precipitate, and thereafter calcining the americium oxalate precipitate to form americium oxide. (Official Gazette)

  20. The Pseudomonas aeruginosa antimetabolite L-2-amino-4-methoxy-trans-3-butenoic acid (AMB is made from glutamate and two alanine residues via a thiotemplate-linked tripeptide precursor

    Directory of Open Access Journals (Sweden)

    Nelson eRojas Murcia

    2015-03-01

    Full Text Available The Pseudomonas aeruginosa toxin L-2-amino-4-methoxy-trans-3-butenoic acid (AMB is a non-proteinogenic amino acid which is toxic for prokaryotes and eukaryotes. Production of AMB requires a five-gene cluster encoding a putative LysE-type transporter (AmbA, two nonribosomal peptide synthetases (AmbB and AmbE, and two iron(II/α-ketoglutarate-dependent oxygenases (AmbC and AmbD. Bioinformatics analysis predicts one thiolation (T domain for AmbB and two T domains (T1 and T2 for AmbE, suggesting that AMB is generated by a processing step from a precursor tripeptide assembled on a thiotemplate. Using a combination of ATP-PPi exchange assays, aminoacylation assays, and mass spectrometry-based analysis of enzyme-bound substrates and pathway intermediates, the AmbB substrate was identified to be L-alanine (L-Ala, while the T1 and T2 domains of AmbE were loaded with L-glutamate (L-Glu and L-Ala, respectively. Loading of L-Ala at T2 of AmbE occurred only in the presence of AmbB, indicative of a trans loading mechanism. In vitro assays performed with AmbB and AmbE revealed the dipeptide L-Glu-L-Ala at T1 and the tripeptide L-Ala-L-Glu-L-Ala attached at T2. When AmbC and AmbD were included in the assay, these peptides were no longer detected. Instead, an L-Ala-AMB-L-Ala tripeptide was found at T2. These data are in agreement with a biosynthetic model in which L-Glu is converted into AMB by the action of AmbC, AmbD and tailoring domains of AmbE. The importance of the flanking L-Ala residues in the precursor tripeptide is discussed.

  1. Fed levels of amino acids are required for the somatotropin-induced increase in muscle protein synthesis.

    Science.gov (United States)

    Wilson, Fiona A; Suryawan, Agus; Orellana, Renán A; Nguyen, Hanh V; Jeyapalan, Asumthia S; Gazzaneo, Maria C; Davis, Teresa A

    2008-10-01

    Chronic somatotropin (pST) treatment in pigs increases muscle protein synthesis and circulating insulin, a known promoter of protein synthesis. Previously, we showed that the pST-mediated rise in insulin could not account for the pST-induced increase in muscle protein synthesis when amino acids were maintained at fasting levels. This study aimed to determine whether the pST-induced increase in insulin promotes skeletal muscle protein synthesis when amino acids are provided at fed levels and whether the response is associated with enhanced translation initiation factor activation. Growing pigs were treated with pST (0 or 180 microg x kg(-1) x day(-1)) for 7 days, and then pancreatic-glucose-amino acid clamps were performed. Amino acids were raised to fed levels in the presence of either fasted or fed insulin concentrations; glucose was maintained at fasting throughout. Muscle protein synthesis was increased by pST treatment and by amino acids (with or without insulin) (P<0.001). In pST-treated pigs, fed, but not fasting, amino acid concentrations further increased muscle protein synthesis rates irrespective of insulin level (P<0.02). Fed amino acids, with or without raised insulin concentrations, increased the phosphorylation of S6 kinase (S6K1) and eukaryotic initiation factor (eIF) 4E-binding protein 1 (4EBP1), decreased inactive 4EBP1.eIF4E complex association, and increased active eIF4E.eIF4G complex formation (P<0.02). pST treatment did not alter translation initiation factor activation. We conclude that the pST-induced stimulation of muscle protein synthesis requires fed amino acid levels, but not fed insulin levels. However, under the current conditions, the response to amino acids is not mediated by the activation of translation initiation factors that regulate mRNA binding to the ribosomal complex.

  2. 76 FR 11965 - Peroxyacetic Acid; Amendment to an Exemption From the Requirement of a Tolerance

    Science.gov (United States)

    2011-03-04

    ..., including primates and humans, and is naturally produced during the fermentation process in a wide range of foods. Furthermore, AA has a long history of use as a food additive, is the main acid in vinegar, and is...

  3. 40 CFR 180.1225 - Decanoic acid; exemption from the requirement of a tolerance.

    Science.gov (United States)

    2010-07-01

    ... acid (up to 170 ppm per application) on food contact surfaces such as equipment, pipelines, tanks, vats, fillers, evaporators, pasteurizers and aseptic equipment in restaurants, food service operations, dairies...

  4. Comparison of topical use of protamine and tranexamic acid in surgical patients requiring cardio-pulmonary bypass

    International Nuclear Information System (INIS)

    Siddiqeh, M.; Siddiqi, R.; Ali, N.; Iqbal, A.; Younus, Z.; Haq, I.U.

    2015-01-01

    To determine the effectiveness of local protamine in reducing post-operative blood loss compared to local tranexamic acid. Study Design: Randomized controlled trial. Place and Duration of Study: Armed Forces Institute of Cardiology/National Institute of Heart Diseases Rawalpindi from January 2011 to September 2011. Patients and Methods: One hundred and twenty cardiac surgical patients were randomly divided into two equal groups, one receiving local protamine while the other group receiving local tranexamic acid before chest closure. The efficiency was measured as post-operative blood loss and requirement of blood and blood products in the post-surgical ICU. Results: Average blood loss in protamine group was significantly less (252.97 ml) compared to tranexamic acid group (680.67 ml). Number of patients requiring no post-operative blood transfusion was significantly higher in protamine group (76.7%) compared to tranexamic acid group (53.3%). Conclusion: Local protamine is more effective in reducing post-operative blood loss than local tranexamic acid. (author)

  5. Apoplastic peroxidases are required for salicylic acid-mediated defense against Pseudomonas syringae.

    Science.gov (United States)

    Mammarella, Nicole D; Cheng, Zhenyu; Fu, Zheng Qing; Daudi, Arsalan; Bolwell, G Paul; Dong, Xinnian; Ausubel, Frederick M

    2015-04-01

    Reactive oxygen species (ROS) generated by NADPH oxidases or apoplastic peroxidases play an important role in the plant defense response. Diminished expression of at least two Arabidopsis thaliana peroxidase encoding genes, PRX33 (At3g49110) and PRX34 (At3g49120), as a consequence of anti-sense expression of a heterologous French bean peroxidase gene (asFBP1.1), were previously shown to result in reduced levels of ROS following pathogen attack, enhanced susceptibility to a variety of bacterial and fungal pathogens, and reduced levels of callose production and defense-related gene expression in response to the microbe associated molecular pattern (MAMP) molecules flg22 and elf26. These data demonstrated that the peroxidase-dependent oxidative burst plays an important role in the elicitation of pattern-triggered immunity (PTI). Further work reported in this paper, however, shows that asFBP1.1 antisense plants are not impaired in all PTI-associated responses. For example, some but not all flg22-elicited genes are induced to lower levels by flg22 in asFPB1.1, and callose deposition in asFPB1.1 is similar to wild-type following infiltration with a Pseudomonas syringae hrcC mutant or with non-host P. syringae pathovars. Moreover, asFPB1.1 plants did not exhibit any apparent defect in their ability to mount a hypersensitive response (HR). On the other hand, salicylic acid (SA)-mediated activation of PR1 was dramatically impaired in asFPB1.1 plants. In addition, P. syringae-elicited expression of many genes known to be SA-dependent was significantly reduced in asFBP1.1 plants. Consistent with this latter result, in asFBP1.1 plants the key regulator of SA-mediated responses, NPR1, showed both dramatically decreased total protein abundance and a failure to monomerize, which is required for its translocation into the nucleus. Copyright © 2014 Elsevier Ltd. All rights reserved.

  6. The dapE-encoded N-succinyl-L,L-Diaminopimelic Acid Desuccinylase from Haemophilus influenzae Contains two Active Site Histidine Residues

    Science.gov (United States)

    Gillner, Danuta M.; Bienvenue, David L.; Nocek, Boguslaw P.; Joachimiak, Andrzej; Zachary, Vincentos; Bennett, Brian; Holz, Richard C.

    2009-01-01

    The catalytic and structural properties of the H67A and H349A altered dapE-encoded N-succinyl-l,l-diaminopimelic acid desuccinylase (DapE) from H. influenzae were investigated. Based on sequence alignment with CPG2 both H67 and H349 were predicted to be Zn(II) ligands. Catalytic activity was observed for the H67A altered DapE enzyme which exhibited kcat = 1.5 ± 0.5 sec−1 and Km = 1.4 ± 0.3 mM. No catalytic activity was observed for H349A under the experimental conditions used. The EPR and electronic absorption data indicate that the Co(II) ion bound to H349A-DapE is analogous to WT DapE after the addition of a single Co(II) ion. The addition of one equivalent of Co(II) to H67A altered DapE provides spectra that are very different from the first Co(II) binding site of the WT enzyme, but similar to the second binding site. The EPR and electronic absorption data, in conjunction with the kinetic data, are consistent with the assignment of H67 and H349 as active site metal ligands for the DapE from H. influenzae. Furthermore, the data suggest that H67 is a ligand in the first metal binding site while H349 resides in the second metal binding site. A three-dimensional homology structure of the DapE from H. influenzae was generated using the X-ray crystal structure of the DapE from N. meningitidis as a template and superimposed on the structure of AAP. This homology structure confirms the assignment of H67 and H349 as active site ligands. The superimposition of the homology model of DapE with the dizinc(II) structure of AAP indicates that within 4.0 Å of the Zn(II) binding sites of AAP, all of the amino acid residues of DapE are nearly identical. PMID:18712420

  7. Construction of hevein (Hev b 6.02) with reduced allergenicity for immunotherapy of latex allergy by comutation of six amino acid residues on the conformational IgE epitopes.

    Science.gov (United States)

    Karisola, Piia; Mikkola, Jari; Kalkkinen, Nisse; Airenne, Kari J; Laitinen, Olli H; Repo, Susanna; Pentikäinen, Olli T; Reunala, Timo; Turjanmaa, Kristiina; Johnson, Mark S; Palosuo, Timo; Kulomaa, Markku S; Alenius, Harri

    2004-02-15

    Recently we have established that IgE Abs bind to conformational epitopes in the N- and C-terminal regions of the major natural rubber latex allergen, hevein (Hev b 6.02). To identify the critical amino acid residues that interact with IgE, the hevein sequence was scanned by using site-specific mutations. Twenty-nine hevein mutants were designed and produced by a baculovirus expression system in insect cells and tested by IgE inhibition-ELISA using sera from 26 latex allergic patients. Six potential IgE-interacting residues of hevein (Arg(5), Lys(10), Glu(29), Tyr(30), His(35), and Gln(38)) were identified and characterized further in detail. Based on these six residues, two triple mutants (Hdelta3A, Hdelta3B) and hevein mutant where all six residues were mutated (Hdelta6), were designed, modeled, and produced. Structural and functional properties of these combinatory mutants were compared experimentally and in silico with those of recombinant hevein. The IgE-binding affinity of the mutants decreased by three to five orders of magnitude as compared with that of recombinant hevein. Skin prick test reactivity of the triple mutant HDelta3A was drastically reduced and that of the six-residue mutant Hdelta6 was completely abolished in all patients examined in this study. The approach presented in this paper offers tools for identification and modification of amino acid residues on conformational epitopes of allergens that interact with IgE. Hevein with a highly reduced ability to bind IgE should provide a valuable candidate molecule for immunotherapy of latex allergy and is anticipated to have a low risk of systemic side effects.

  8. Acidic pH sensing in the bacterial cytoplasm is required for Salmonella virulence.

    Science.gov (United States)

    Choi, Jeongjoon; Groisman, Eduardo A

    2016-09-01

    pH regulates gene expression, biochemical activities and cellular behaviors. A mildly acidic pH activates the master virulence regulatory system PhoP/PhoQ in the facultative intracellular pathogen Salmonella enterica serovar Typhimurium. The sensor PhoQ harbors an extracytoplasmic domain implicated in signal sensing, and a cytoplasmic domain controlling activation of the regulator PhoP. We now report that, surprisingly, a decrease in Salmonella's own cytoplasmic pH induces transcription of PhoP-activated genes even when the extracytoplasmic pH remains neutral. Amino acid substitutions in PhoQ's cytoplasmic domain hindered activation by acidic pH and attenuated virulence in mice, but did not abolish activation by low Mg(2+) or the antimicrobial peptide C18G. Conversely, removal of PhoQ's extracytoplasmic domains prevented the response to the latter PhoQ-activating signals but not to acidic pH. PhoP-dependent genes were minimally induced by acidic pH in the non-pathogenic species Salmonella bongori but were activated by low Mg(2+) and C18G as in pathogenic S. enterica. Our findings indicate that the sensor PhoQ enables S. enterica to respond to both host- and bacterial-derived signals that alter its cytoplasmic pH. © 2016 John Wiley & Sons Ltd.

  9. Solid residues

    International Nuclear Information System (INIS)

    Mulder, E.; Duin, P.J. van; Grootenboer, G.J.

    1995-01-01

    A summary is presented of the many investigations that have been done on solid residues of atmospheric fluid bed combustion (AFBC). These residues are bed ash, cyclone ash and bag filter ash. Physical and chemical properties are discussed and then the various uses of residues (in fillers, bricks, gravel, and for recovery of aluminium) are summarised. Toxicological properties of fly ash and stack ash are discussed as are risks of pneumoconiosis for workers handling fly ash, and contamination of water by ashes. On the basis of present information it is concluded that risks to public health from exposure to emissions of coal fly ash from AFBC appear small or negligible as are health risk to workers in the coal fly ash processing industry. 35 refs., 5 figs., 12 tabs

  10. Host-Derived Sialic Acids Are an Important Nutrient Source Required for Optimal Bacterial Fitness In Vivo.

    Science.gov (United States)

    McDonald, Nathan D; Lubin, Jean-Bernard; Chowdhury, Nityananda; Boyd, E Fidelma

    2016-04-12

    A major challenge facing bacterial intestinal pathogens is competition for nutrient sources with the host microbiota.Vibrio cholerae is an intestinal pathogen that causes cholera, which affects millions each year; however, our knowledge of its nutritional requirements in the intestinal milieu is limited. In this study, we demonstrated that V. cholerae can grow efficiently on intestinal mucus and its component sialic acids and that a tripartite ATP-independent periplasmic SiaPQM strain, transporter-deficient mutant NC1777, was attenuated for colonization using a streptomycin-pretreated adult mouse model. In in vivo competition assays, NC1777 was significantly outcompeted for up to 3 days postinfection. NC1777 was also significantly outcompeted in in vitro competition assays in M9 minimal medium supplemented with intestinal mucus, indicating that sialic acid uptake is essential for fitness. Phylogenetic analyses demonstrated that the ability to utilize sialic acid was distributed among 452 bacterial species from eight phyla. The majority of species belonged to four phyla, Actinobacteria (members of Actinobacillus, Corynebacterium, Mycoplasma, and Streptomyces), Bacteroidetes (mainly Bacteroides, Capnocytophaga, and Prevotella), Firmicutes (members of Streptococcus, Staphylococcus, Clostridium, and Lactobacillus), and Proteobacteria (including Escherichia, Shigella, Salmonella, Citrobacter, Haemophilus, Klebsiella, Pasteurella, Photobacterium, Vibrio, and Yersinia species), mostly commensals and/or pathogens. Overall, our data demonstrate that the ability to take up host-derived sugars and sialic acid specifically allows V. cholerae a competitive advantage in intestinal colonization and that this is a trait that is sporadic in its occurrence and phylogenetic distribution and ancestral in some genera but horizontally acquired in others. Sialic acids are nine carbon amino sugars that are abundant on all mucous surfaces. The deadly human pathogen Vibrio cholerae contains

  11. Evolutionary divergence of plant borate exporters and critical amino acid residues for the polar localization and boron-dependent vacuolar sorting of AtBOR1

    KAUST Repository

    Wakuta, Shinji

    2015-01-24

    Boron (B) is an essential micronutrient for plants but is toxic when accumulated in excess. The plant BOR family encodes plasma membrane-localized borate exporters (BORs) that control translocation and homeostasis of B under a wide range of conditions. In this study, we examined the evolutionary divergence of BORs among terrestrial plants and showed that the lycophyte Selaginella moellendorffii and angiosperms have evolved two types of BOR (clades I and II). Clade I includes AtBOR1 and homologs previously shown to be involved in efficient transport of B under conditions of limited B availability. AtBOR1 shows polar localization in the plasma membrane and high-B-induced vacuolar sorting, important features for efficient B transport under low-B conditions, and rapid down-regulation to avoid B toxicity. Clade II includes AtBOR4 and barley Bot1 involved in B exclusion for high-B tolerance. We showed, using yeast complementation and B transport assays, that three genes in S. moellendorffii, SmBOR1 in clade I and SmBOR3 and SmBOR4 in clade II, encode functional BORs. Furthermore, amino acid sequence alignments identified an acidic di-leucine motif unique in clade I BORs. Mutational analysis of AtBOR1 revealed that the acidic di-leucine motif is required for the polarity and high-B-induced vacuolar sorting of AtBOR1. Our data clearly indicated that the common ancestor of vascular plants had already acquired two types of BOR for low- and high-B tolerance, and that the BOR family evolved to establish B tolerance in each lineage by adapting to their environments. © The Author 2015. Published by Oxford University Press on behalf of Japanese Society of Plant Physiologists.

  12. Branched-Chain Amino Acids Are Required for the Survival and Virulence of Actinobacillus pleuropneumoniae in Swine▿

    OpenAIRE

    Subashchandrabose, Sargurunathan; LeVeque, Rhiannon M.; Wagner, Trevor K.; Kirkwood, Roy N.; Kiupel, Matti; Mulks, Martha H.

    2009-01-01

    In Actinobacillus pleuropneumoniae, which causes porcine pleuropneumonia, ilvI was identified as an in vivo-induced (ivi) gene and encodes the enzyme acetohydroxyacid synthase (AHAS) required for branched-chain amino acid (BCAA) biosynthesis. ilvI and 7 of 32 additional ivi promoters were upregulated in vitro when grown in chemically defined medium (CDM) lacking BCAA. Based on these observations, we hypothesized that BCAA would be found at limiting concentrations in pulmonary secretions and t...

  13. Mass spectrometry and site-directed mutagenesis identify several autophosphorylated residues required for the activity of PrkC, a Ser/Thr kinase from Bacillus subtilis

    DEFF Research Database (Denmark)

    Madec, Edwige; Stensballe, Allan; Kjellström, Sven

    2003-01-01

    We have shown recently that PrkC, which is involved in developmental processes in Bacillus subtilis, is a Ser/Thr kinase with features of the receptor kinase family of eukaryotic Hanks kinases. In this study, we expressed and purified from Escherichia coli the cytoplasmic domain of PrkC containing...... the kinase and a short juxtamembrane region. This fragment, which we designate PrkCc, undergoes autophosphorylation in E.coli. PrkCc is further autophosphorylated in vitro, apparently through a trans-kinase, intermolecular reaction. PrkC also displays kinase activity with myelin basic protein. Using high...... mass accuracy electrospray tandem mass spectrometry (LC-MS/MS) and nanoelectrospray tandem mass spectrometry, we identified seven phosphorylated threonine and one serine residue in PrkCc. All the corresponding residues were replaced by systematic site-directed mutagenesis and the purified mutant...

  14. Microbiota-Derived Short-Chain Fatty Acids Modulate Expression of Campylobacter jejuni Determinants Required for Commensalism and Virulence.

    Science.gov (United States)

    Luethy, Paul M; Huynh, Steven; Ribardo, Deborah A; Winter, Sebastian E; Parker, Craig T; Hendrixson, David R

    2017-05-09

    Campylobacter jejuni promotes commensalism in the intestinal tracts of avian hosts and diarrheal disease in humans, yet components of intestinal environments recognized as spatial cues specific for different intestinal regions by the bacterium to initiate interactions in either host are mostly unknown. By analyzing a C. jejuni acetogenesis mutant defective in converting acetyl coenzyme A (Ac-CoA) to acetate and commensal colonization of young chicks, we discovered evidence for in vivo microbiota-derived short-chain fatty acids (SCFAs) and organic acids as cues recognized by C. jejuni that modulate expression of determinants required for commensalism. We identified a set of C. jejuni genes encoding catabolic enzymes and transport systems for amino acids required for in vivo growth whose expression was modulated by SCFAs. Transcription of these genes was reduced in the acetogenesis mutant but was restored upon supplementation with physiological concentrations of the SCFAs acetate and butyrate present in the lower intestinal tracts of avian and human hosts. Conversely, the organic acid lactate, which is abundant in the upper intestinal tract where C. jejuni colonizes less efficiently, reduced expression of these genes. We propose that microbiota-generated SCFAs and lactate are cues for C. jejuni to discriminate between different intestinal regions. Spatial gradients of these metabolites likely allow C. jejuni to locate preferred niches in the lower intestinal tract and induce expression of factors required for intestinal growth and commensal colonization. Our findings provide insights into the types of cues C. jejuni monitors in the avian host for commensalism and likely in humans to promote diarrheal disease. IMPORTANCE Campylobacter jejuni is a commensal of the intestinal tracts of avian species and other animals and a leading cause of diarrheal disease in humans. The types of cues sensed by C. jejuni to influence responses to promote commensalism or

  15. Mitochondrial fatty acid synthesis is required for normal mitochondrial morphology and function in Trypanosoma brucei

    Czech Academy of Sciences Publication Activity Database

    Guler, J. L.; Kriegová, Eva; Smith, T. K.; Lukeš, Julius; Englund, P. T.

    2008-01-01

    Roč. 67, č. 5 (2008), s. 1125-1142 ISSN 0950-382X R&D Projects: GA ČR GA204/06/1558; GA MŠk LC07032; GA MŠk 2B06129 Grant - others:NIH(US) AI21334; Wellcome Trust(GB) 067441 Institutional research plan: CEZ:AV0Z60220518 Keywords : Trypanosoma * mitochondrion * fatty acid * RNA interference Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 5.213, year: 2008

  16. Complying with Clean Air Act acid rain provisions: A case history of required air quality analyses

    International Nuclear Information System (INIS)

    McComb, G.G. Jr.; Naperkoski, G.J.; Rogers, F.A.

    1990-01-01

    Clean Air Act Amendments being considered by Congress require SO 2 emissions reductions from numerous large power generation sources nationwide. As currently written, these amendments also require that the affected sources must continue to comply with all provisions of the existing Clean Air Act while achieving the required reductions. United Engineers and Constructors is presently assisting utilities in the evaluation of compliance options for units totaling over 18,000 MW. The methods of achieving compliance with the probable requirements of the Act most often include the retrofit installation of SO 2 scrubbers. A study designed to determine permitting issues and the scope of air quality analyses required to demonstrate the regulatory acceptability of installation of wet scrubbing systems has been completed for units totaling a portion of the above-referenced 18,000 MW. The study results show that, under certain commonly occurring circumstances, there is a risk of creating National Ambient Air Quality Standards contraventions for SO 2 and NO 2 when scrubbers are installed at an existing facility. Any such contraventions subject the plant to state and/or federal enforcement actions. In addition, installation of materials handling equipment for lime stone can trigger Prevention of Significant Deterioration requirements as a major modification. This paper is divided into two major areas. The first deals with the air quality regulatory requirements imposed upon installation of pollution control equipment. The first section is further sub-divided into two sections: one covering requirements emanating from the 1977 Clean Air Act Amendments and its implementing regulations and the other the regulatory requirements of the new Clean Air Act Amendments. This section on regulatory requirements provides background information for the understanding of the second major section of the paper which gives the results of the hypothetical case study

  17. Extended hormone binding site of the human thyroid stimulating hormone receptor: distinctive acidic residues in the hinge region are involved in bovine thyroid stimulating hormone binding and receptor activation.

    Science.gov (United States)

    Mueller, Sandra; Kleinau, Gunnar; Jaeschke, Holger; Paschke, Ralf; Krause, Gerd

    2008-06-27

    The human thyroid stimulating hormone receptor (hTSHR) belongs to the glycoprotein hormone receptors that bind the hormones at their large extracellular domain. The extracellular hinge region of the TSHR connects the N-terminal leucine-rich repeat domain with the membrane-spanning serpentine domain. From previous studies we reasoned that apart from hormone binding at the leucine-rich repeat domain, additional multiple hormone contacts might exist at the hinge region of the TSHR by complementary charge-charge recognition. Here we investigated highly conserved charged residues in the hinge region of the TSHR by site-directed mutagenesis to identify amino acids interacting with bovine TSH (bTSH). Indeed, the residues Glu-297, Glu-303, and Asp-382 in the TSHR hinge region are essential for bTSH binding and partially for signal transduction. Side chain substitutions showed that the negative charge of Glu-297 and Asp-382 is necessary for recognition of bTSH by the hTSHR. Multiple combinations of alanine mutants of the identified positions revealed an increased negative effect on hormone binding. An assembled model suggests that the deciphered acidic residues form negatively charged patches at the hinge region resulting in an extended binding mode for bTSH on the hTSHR. Our data indicate that certain positively charged residues of bTSH might be involved in interaction with the identified negatively charged amino acids of the hTSHR hinge region. We demonstrate that the hinge region represents an extracellular intermediate connector for both hormone binding and signal transduction of the hTSHR.

  18. 40 CFR 180.1019 - Sulfuric acid; exemption from the requirement of a tolerance.

    Science.gov (United States)

    2010-07-01

    ... requirement of a tolerance in cattle, meat; goat, meat; hog, meat; horse, meat; sheep, meat; poultry, fat; poultry, meat; poultry, meat, byproducts; egg; milk; fish, shellfish, and irrigated crops when it results...

  19. West Nile virus replication requires fatty acid synthesis but is independent on phosphatidylinositol-4-phosphate lipids.

    Directory of Open Access Journals (Sweden)

    Miguel A Martín-Acebes

    Full Text Available West Nile virus (WNV is a neurovirulent mosquito-borne flavivirus, which main natural hosts are birds but it also infects equines and humans, among other mammals. As in the case of other plus-stranded RNA viruses, WNV replication is associated to intracellular membrane rearrangements. Based on results obtained with a variety of viruses, different cellular processes have been shown to play important roles on these membrane rearrangements for efficient viral replication. As these processes are related to lipid metabolism, fatty acid synthesis, as well as generation of a specific lipid microenvironment enriched in phosphatidylinositol-4-phosphate (PI4P, has been associated to it in other viral models. In this study, intracellular membrane rearrangements following infection with a highly neurovirulent strain of WNV were addressed by means of electron and confocal microscopy. Infection of WNV, and specifically viral RNA replication, were dependent on fatty acid synthesis, as revealed by the inhibitory effect of cerulenin and C75, two pharmacological inhibitors of fatty acid synthase, a key enzyme of this process. However, WNV infection did not induce redistribution of PI4P lipids, and PI4P did not localize at viral replication complex. Even more, WNV multiplication was not inhibited by the use of the phosphatidylinositol-4-kinase inhibitor PIK93, while infection by the enterovirus Coxsackievirus B5 was reduced. Similar features were found when infection by other flavivirus, the Usutu virus (USUV, was analyzed. These features of WNV replication could help to design specific antiviral approaches against WNV and other related flaviviruses.

  20. Branched-chain amino acid interactions with reference to amino acid requirements in adult men: Valine metabolism at different leucine intakes

    International Nuclear Information System (INIS)

    Pelletier, V.; Marks, L.; Wagner, D.A.; Hoerr, R.A.; Young, V.R.

    1991-01-01

    The authors explored whether the oxidation of valine and by implication the physiological requirement for this amino acid are affected by changes in leucine intake over a physiological range. Six young adult men received, in random order, four L-amino acid-based diets for 5 d supplying either 20 or 10 mg valine.kg body wt-1.d-1, each in combination with 80 or 40 mg leucine.kg-1.d-1. On day 6 subjects were studied with an 8-h continuous intravenous infusion of [1-13C]valine (and [2H3]leucine) to determine valine oxidation in the fasted state (first 3 h) and fed state (last 5 h). Valine oxidation in the fasted state was similar among all diets but was lower (P less than 0.05) in the fed state for the 10 vs 20 mg valine.kg-1.d-1 intake. Leucine intake did not affect valine oxidation. Mean daily valine balance approximated +1.3 mg.kg-1.d-1 for the 20-mg intake and -1.6 mg.kg-1.d-1 for the 10-mg intake. These findings support our previously suggested mean valine requirement estimate of approximately 20 mg.kg-1.d-1

  1. EGFR-dependent signalling reduced and p38 dependent apoptosis required by Gallic acid in Malignant Mesothelioma cells.

    Science.gov (United States)

    Demiroglu-Zergeroglu, Asuman; Candemir, Gulsife; Turhanlar, Ebru; Sagir, Fatma; Ayvali, Nurettin

    2016-12-01

    The unrestrained EGFR signalling contributes to malignant phenotype in a number of cancers including Malignant Mesotheliomas. Present study was designed to evaluate EGFR-dependent anti-proliferative and apoptotic effects of Gallic acid in transformed Mesothelial (MeT-5A) and Malignant Mesothelioma (SPC212) cells. Gallic acid reduced the viability of Malignant Mesothelioma cells in a concentration and time-dependent manner. However, viability of mesothelial cells reduced only at high concentration and longer time periods. Gallic acid restrained the activation of EGFR, ERK1/2 and AKT proteins and down regulated expression of Cyclin D and Bcl-2 genes, but upregulated the expression of p21 gene in EGF-induced SPC212 cells. GA-induced transitory G1 arrest and triggered mitochondrial and death receptor mediated apoptosis, which requires p38MAPK activation. The data provided here indicate that GA is able to inhibit EGFR dependent proliferation and survival signals and induces p38 pathway dependent apoptosis in Malignant Mesothelioma cells. On the basis of these experimental findings it is worthwhile to investigate further the biological activity of Gallic acid on other Mesothelioma cell lines harbouring aberrant EGFR signals. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

  2. Residual basins

    International Nuclear Information System (INIS)

    D'Elboux, C.V.; Paiva, I.B.

    1980-01-01

    Exploration for uranium carried out over a major portion of the Rio Grande do Sul Shield has revealed a number of small residual basins developed along glacially eroded channels of pre-Permian age. Mineralization of uranium occurs in two distinct sedimentary units. The lower unit consists of rhythmites overlain by a sequence of black shales, siltstones and coal seams, while the upper one is dominated by sandstones of probable fluvial origin. (Author) [pt

  3. Requirement of Gamma-Carboxyglutamic Acid Modification and Phosphatidylserine Binding for the Activation of Tyro3, Axl, and Mertk Receptors by Growth Arrest-Specific 6

    Directory of Open Access Journals (Sweden)

    Ke Geng

    2017-11-01

    Full Text Available The Tyro3, Axl, and Mertk (TAM receptors are homologous type I receptor tyrosine kinases that have critical functions in the clearance of apoptotic cells in multicellular organisms. TAMs are activated by their endogenous ligands, growth arrest-specific 6 (Gas6, and protein S (Pros1, that function as bridging molecules between externalized phosphatidylserine (PS on apoptotic cells and the TAM ectodomains. However, the molecular mechanisms by which Gas6/Pros1 promote TAM activation remains elusive. Using TAM/IFNγR1 reporter cell lines to monitor functional TAM activity, we found that Gas6 activity was exquisitely dependent on vitamin K-mediated γ-carboxylation, whereby replacing vitamin K with anticoagulant warfarin, or by substituting glutamic acid residues involved in PS binding, completely abrogated Gas6 activity as a TAM ligand. Furthermore, using domain and point mutagenesis, Gas6 activity also required both an intact Gla domain and intact EGF-like domains, suggesting these domains function cooperatively in order to achieve TAM activation. Despite the requirement of γ-carboxylation and the functional Gla domain, non-γ-carboxylated Gas6 and Gla deletion/EGF-like domain deletion mutants still retained their ability to bind TAMs and acted as blocking decoy ligands. Finally, we found that distinct sources of PS-positive cells/vesicles (including apoptotic cells, calcium-induced stressed cells, and exosomes bound Gas6 and acted as cell-derived or exosome-derived ligands to activate TAMs. Taken together, our findings indicate that PS is indispensable for TAM activation by Gas6, and by inference, provides new perspectives on how PS, regulates TAM receptors and efferocytosis.

  4. The TIP30 protein complex, arachidonic acid and coenzyme A are required for vesicle membrane fusion.

    Directory of Open Access Journals (Sweden)

    Chengliang Zhang

    Full Text Available Efficient membrane fusion has been successfully mimicked in vitro using artificial membranes and a number of cellular proteins that are currently known to participate in membrane fusion. However, these proteins are not sufficient to promote efficient fusion between biological membranes, indicating that critical fusogenic factors remain unidentified. We have recently identified a TIP30 protein complex containing TIP30, acyl-CoA synthetase long-chain family member 4 (ACSL4 and Endophilin B1 (Endo B1 that promotes the fusion of endocytic vesicles with Rab5a vesicles, which transport endosomal acidification enzymes vacuolar (H⁺-ATPases (V-ATPases to the early endosomes in vivo. Here, we demonstrate that the TIP30 protein complex facilitates the fusion of endocytic vesicles with Rab5a vesicles in vitro. Fusion of the two vesicles also depends on arachidonic acid, coenzyme A and the synthesis of arachidonyl-CoA by ACSL4. Moreover, the TIP30 complex is able to transfer arachidonyl groups onto phosphatidic acid (PA, producing a new lipid species that is capable of inducing close contact between membranes. Together, our data suggest that the TIP30 complex facilitates biological membrane fusion through modification of PA on membranes.

  5. Highly acidic C-terminal domain of pp32 is required for the interaction with histone chaperone, TAF-Ibeta.

    Science.gov (United States)

    Lee, In-Seon; Oh, Sang-Min; Kim, Sung-Mi; Lee, Dong-Seok; Seo, Sang-Beom

    2006-12-01

    We have previously reported that INHAT (inhibitor of acetyltransferases) complex subunits, TAF (template activating factor)-Ialpha, TAF-Ibeta and pp32 can inhibit histone acetylation and HAT (histone acetyltransferase)-dependent transcription by binding to histones. Evidences are accumulating that INHAT complex subunits have important regulatory roles in various cellular activities such as replication, transcription, and apoptosis etc. However, how these subunits interact each other remains largely unknown. Using immunoprecipitation (IP) and protein-protein interaction assays with TAF-Ibeta and pp32 deletion mutant proteins, we identify INHAT complex subunits, TAF-Ibeta and pp32 interaction requires highly acidic C-terminal domain of pp32. We also show that the interaction between the INHAT complex subunits is stronger in the presence of histones. In this study, we report that the synergistic inhibition of HAT-mediated transcription by TAF-Ibeta and pp32 is dependent on the highly acidic C-terminal domain of pp32.

  6. Differences in essential fatty acid requirements by enteral and parenteral routes of administration in patients with fat malabsorption

    DEFF Research Database (Denmark)

    Jeppesen, Palle B; Høy, Carl-Erik; Mortensen, Per B

    1999-01-01

    Background: Essential fatty acid (EFA) requirements of patients receiving home parenteral nutrition (HPN) are uncertain. Objective: The objective was to evaluate the influence of the route of administration (enteral compared with parenteral) on plasma phospholipid EFA concentrations. Design......: Intestinal absorption, parenteral supplement of EFAs, and plasma phospholipid EFA concentrations were investigated in balance studies in 4 groups (A, B, C, and D) of 10 patients with short-bowel syndrome and a fecal loss of >2000 kJ/d. Groups A (fat malabsorption 50%) did...... absorption was negligible in groups C and D. Thus, intestinal absorption of EFAs in group A. corresponded to parenteral EFA supplements in group C, whereas group D was almost totally deprived of EFAs. The median plasma phospholipid concentration of linoleic acid decreased by 21.9%, > 16.3%, >13.8%, 11...

  7. 5,5'-Dithiobis-(2-nitrobenzoic acid) as a probe for a non-essential cysteine residue at the medium chain acyl-coenzyme A dehydrogenase binding site of the human 'electron transferring flavoprotein' (ETF).

    Science.gov (United States)

    Parker, A; Engel, P C

    1999-01-01

    Human 'electron transferring flavoprotein' (ETF) was inactivated by the thiol-specific reagent 5,5'-dithiobis-(2-nitrobenzoic acid) (DTNB). The kinetic profile showed the reaction followed pseudo-first-order kinetics during the initial phase of inactivation. Monitoring the release of 5-thio-2-nitrobenzoate (TNB) showed that modification of 1 cysteine residue was responsible for the loss of activity. The inactivation of ETF by DTNB could be reversed upon incubation with thiol-containing reagents. The loss of activity was prevented by the inclusion of medium chain acyl-CoA dehydrogenase (MCAD) and octanoyl-CoA. Cyanolysis of the DTNB modified-ETF with KCN led to the release of TNB accompanied presumably by the formation of the thio-cyano enzyme and with almost full recovery of activity. Conservation studies and the lack of 100% inactivation, however, suggested that this cysteine residue is not essential for the interaction with MCAD.

  8. Aspergillus fumigatus Does Not Require Fatty Acid Metabolism via Isocitrate Lyase for Development of Invasive Aspergillosis▿

    OpenAIRE

    Schöbel, Felicitas; Ibrahim-Granet, Oumaïma; Avé, Patrick; Latgé, Jean-Paul; Brakhage, Axel A.; Brock, Matthias

    2006-01-01

    Aspergillus fumigatus is the most prevalent airborne filamentous fungus causing invasive aspergillosis in immunocompromised individuals. Only a limited number of determinants directly associated with virulence are known, and the metabolic requirements of the fungus to grow inside a host have not yet been investigated. Previous studies on pathogenic microorganisms, i.e., the bacterium Mycobacterium tuberculosis and the yeast Candida albicans, have revealed an essential role for isocitrate lyas...

  9. Actinide recovery from pyrochemical residues

    International Nuclear Information System (INIS)

    Avens, L.R.; Clifton, D.G.; Vigil, A.R.

    1985-05-01

    We demonstrated a new process for recovering plutonium and americium from pyrochemical waste. The method is based on chloride solution anion exchange at low acidity, or acidity that eliminates corrosive HCl fumes. Developmental experiments of the process flow chart concentrated on molten salt extraction (MSE) residues and gave >95% plutonium and >90% americium recovery. The recovered plutonium contained 6 2- from high-chloride low-acid solution. Americium and other metals are washed from the ion exchange column with lN HNO 3 -4.8M NaCl. After elution, plutonium is recovered by hydroxide precipitation, and americium is recovered by NaHCO 3 precipitation. All filtrates from the process can be discardable as low-level contaminated waste. Production-scale experiments are in progress for MSE residues. Flow charts for actinide recovery from electro-refining and direct oxide reduction residues are presented and discussed

  10. Murine elongation factor 1 alpha (EF-1 alpha) is posttranslationally modified by novel amide-linked ethanolamine-phosphoglycerol moieties. Addition of ethanolamine-phosphoglycerol to specific glutamic acid residues on EF-1 alpha

    International Nuclear Information System (INIS)

    Whiteheart, S.W.; Shenbagamurthi, P.; Chen, L.; Cotter, R.J.; Hart, G.W.

    1989-01-01

    Elongation Factor 1 alpha (EF-1 alpha), an important eukaryotic translation factor, transports charged aminoacyl-tRNA from the cytosol to the ribosomes during poly-peptide synthesis. Metabolic radiolabeling with [ 3 H] ethanolamine shows that, in all cells examined, EF-1 alpha is the major radiolabeled protein. Radiolabeled EF-1 alpha has an apparent Mr = 53,000 and a basic isoelectric point. It is cytosolic and does not contain N-linked oligosaccharides. Trypsin digestion of murine EF-1 alpha generated two major [ 3 H]ethanolamine-labeled peptides. Three peptides were sequenced and were identical to two distinct regions of the human EF-1 alpha protein. Blank sequencing cycles coinciding with glutamic acid in the human cDNA-derived sequence were also found to release [ 3 H]ethanolamine, and compositional analysis of these peptides confirmed the presence of glutamic acid. Dansylation analysis demonstrates that the amine group of the ethanolamine is blocked. These results indicate that EF-1 alpha is posttranslationally modified by the covalent attachment of ethanolamine via an amide bond to at least two specific glutamic acid residues (Glu-301 and Glu-374). The hydroxyl group of the attached ethanolamine was shown by mass spectrometry and compositional analysis, to be further modified by the addition of a phosphoglycerol unit. This novel posttranslational modification may represent an important alteration of EF-1 alpha, comparable to the regulatory effects of posttranslational methylation of EF-1 alpha lysine residues

  11. Treatment of the acid mine drainage residue for uranium recovery; Tratamento do resíduo da drenagem ácida de mina para recuperação de urânio

    Energy Technology Data Exchange (ETDEWEB)

    Dias, M.M.; Horta, D.G., E-mail: mmartinsdias@uol.com.br [Universidade Federal de Alfenas, Núcleo de Engenharia de Minas, Poços de Caldas-MG (Brazil); Fukuma, H.T.; Villegas, R.A.S.; Carvalho, C.H.T. de; Silva, A.C. da [Comissão Nacional de Energia Nuclear (LAPOC/CNEN), Pocos de Caldas, MG (Brazil). Lab. de Pocos de Caldas/Setor de Processos Químicos

    2017-07-01

    Acid mine drainage (AMD) is a process that occurs in many mining that have sulfide ores. With water and oxygen, several metals are oxidized, one example being uranium. At the mine pit of the Osamu Utsumi Mine located at INB - Caldas and in two other boot-wastes (mining waste pile), AMD is present and currently, without a technological solution. The acidic water present in the pit is treated with hydrated lime, generating water for disposal and an alkaline residue called calcium diuranate - DUCA. The DUCA has a concentration of approximately 0.32% U{sub 3}O{sub 8}, which makes interesting the development of a process for extracting that metal. One of the processes that can be used is leaching. For this study, it was decided to evaluate the alkaline leaching to extract the uranium present in the residue. It is necessary to optimize operational parameters for the process: percentage of solids, concentration of leaching agent in solution, temperature and reaction time. With these parameters, it is possible to improve the leaching so that the largest amount of uranium is extracted from the sample, to help solve the environmental impact caused by the wastewater from the treatment of acid waters and, in addition, to give an economical destination for this metal that is contained in the deposited DUCA.

  12. Consensus of sample-balanced classifiers for identifying ligand-binding residue by co-evolutionary physicochemical characteristics of amino acids

    KAUST Repository

    Chen, Peng

    2013-01-01

    Protein-ligand binding is an important mechanism for some proteins to perform their functions, and those binding sites are the residues of proteins that physically bind to ligands. So far, the state-of-the-art methods search for similar, known

  13. Poor results of 5-aminolevulinic acid-photodynamic therapy for residual high-grade dysplasia and early cancer in barrett esophagus after endoscopic resection

    NARCIS (Netherlands)

    Peters, F.; Kara, M.; Rosmolen, W.; Aalders, M.; ten Kate, F.; Krishnadath, K.; van Lanschot, J.; Fockens, P.; Bergman, J.

    2005-01-01

    BACKGROUND AND STUDY AIMS: The aim of the study was to evaluate the efficacy of photodynamic therapy (PDT) in the treatment of residual high-grade dysplasia or early cancer (HGD/EC) after endoscopic resection in Barrett esophagus. PATIENTS AND METHODS: Study patients were separated into group A,

  14. Microwave assisted solvent extraction and coupled-column reversed-phase liquid chromatography with UV detection use of an analytical restricted-access-medium column for the efficient multi-residue analysis of acidic pesticides in soils.

    Science.gov (United States)

    Hogendoom, E A; Huls, R; Dijkman, E; Hoogerbrugge, R

    2001-12-14

    A screening method has been developed for the determination of acidic pesticides in various types of soils. Methodology is based on the use of microwave assisted solvent extraction (MASE) for fast and efficient extraction of the analytes from the soils and coupled-column reversed-phase liquid chromatography (LC-LC) with UV detection at 228 nm for the instrumental analysis of uncleaned extracts. Four types of soils, including sand, clay and peat, with a range in organic matter content of 0.3-13% and ten acidic pesticides of different chemical families (bentazone, bromoxynil, metsulfuron-methyl, 2,4-D, MCPA, MCPP, 2,4-DP, 2,4,5-T, 2,4-DB and MCPB) were selected as matrices and analytes, respectively. The method developed included the selection of suitable MASE and LC-LC conditions. The latter consisted of the selection of a 5-microm GFF-II internal surface reversed-phase (ISRP, Pinkerton) analytical column (50 x 4.6 mm, I.D.) as the first column in the RAM-C18 configuration in combination with an optimised linear gradient elution including on-line cleanup of sample extracts and reconditioning of the columns. The method was validated with the analysis of freshly spiked samples and samples with aged residues (120 days). The four types of soils were spiked with the ten acidic pesticides at levels between 20 and 200 microg/kg. Weighted regression of the recovery data showed for most analyte-matrix combinations, including freshly spiked samples and aged residues, that the method provides overall recoveries between 60 and 90% with relative standard deviations of the intra-laboratory reproducibility's between 5 and 25%; LODs were obtained between 5 and 50 microg/kg. Evaluation of the data set with principal component analysis revealed that the parameters (i) increase of organic matter content of the soil samples and (ii) aged residues negatively effect the recovery of the analytes.

  15. Protein turnover, amino acid requirements and recommendations for athletes and active populations

    International Nuclear Information System (INIS)

    Poortmans, J.R.; Carpentier, A.; Pereira-Lancha, L.O.; Lancha, A. Jr.

    2012-01-01

    Skeletal muscle is the major deposit of protein molecules. As for any cell or tissue, total muscle protein reflects a dynamic turnover between net protein synthesis and degradation. Noninvasive and invasive techniques have been applied to determine amino acid catabolism and muscle protein building at rest, during exercise and during the recovery period after a single experiment or training sessions. Stable isotopic tracers ( 13 C-lysine, 15 N-glycine, 2 H 5 -phenylalanine) and arteriovenous differences have been used in studies of skeletal muscle and collagen tissues under resting and exercise conditions. There are different fractional synthesis rates in skeletal muscle and tendon tissues, but there is no major difference between collagen and myofibrillar protein synthesis. Strenuous exercise provokes increased proteolysis and decreased protein synthesis, the opposite occurring during the recovery period. Individuals who exercise respond differently when resistance and endurance types of contractions are compared. Endurance exercise induces a greater oxidative capacity (enzymes) compared to resistance exercise, which induces fiber hypertrophy (myofibrils). Nitrogen balance (difference between protein intake and protein degradation) for athletes is usually balanced when the intake of protein reaches 1.2 g·kg −1 ·day −1 compared to 0.8 g·kg −1 ·day −1 in resting individuals. Muscular activities promote a cascade of signals leading to the stimulation of eukaryotic initiation of myofibrillar protein synthesis. As suggested in several publications, a bolus of 15-20 g protein (from skimmed milk or whey proteins) and carbohydrate (± 30 g maltodextrine) drinks is needed immediately after stopping exercise to stimulate muscle protein and tendon collagen turnover within 1 h

  16. Protein turnover, amino acid requirements and recommendations for athletes and active populations

    Energy Technology Data Exchange (ETDEWEB)

    Poortmans, J.R.; Carpentier, A. [Laboratory for Biometry and Sport Nutrition, Faculty of Motor Sciences, Free University of Brussels, Brussels (Belgium); Pereira-Lancha, L.O. [Departamento de Nutrição, Instituto Vita, São Paulo, SP (Brazil); Lancha, A. Jr. [Laboratório de Nutrição Aplicada à Atividade Motora, Escola de Educação Física e Esporte, Universidade de São Paulo, São Paulo, SP (Brazil)

    2012-06-08

    Skeletal muscle is the major deposit of protein molecules. As for any cell or tissue, total muscle protein reflects a dynamic turnover between net protein synthesis and degradation. Noninvasive and invasive techniques have been applied to determine amino acid catabolism and muscle protein building at rest, during exercise and during the recovery period after a single experiment or training sessions. Stable isotopic tracers ({sup 13}C-lysine, {sup 15}N-glycine, {sup 2}H{sub 5}-phenylalanine) and arteriovenous differences have been used in studies of skeletal muscle and collagen tissues under resting and exercise conditions. There are different fractional synthesis rates in skeletal muscle and tendon tissues, but there is no major difference between collagen and myofibrillar protein synthesis. Strenuous exercise provokes increased proteolysis and decreased protein synthesis, the opposite occurring during the recovery period. Individuals who exercise respond differently when resistance and endurance types of contractions are compared. Endurance exercise induces a greater oxidative capacity (enzymes) compared to resistance exercise, which induces fiber hypertrophy (myofibrils). Nitrogen balance (difference between protein intake and protein degradation) for athletes is usually balanced when the intake of protein reaches 1.2 g·kg{sup −1}·day{sup −1} compared to 0.8 g·kg{sup −1}·day{sup −1} in resting individuals. Muscular activities promote a cascade of signals leading to the stimulation of eukaryotic initiation of myofibrillar protein synthesis. As suggested in several publications, a bolus of 15-20 g protein (from skimmed milk or whey proteins) and carbohydrate (± 30 g maltodextrine) drinks is needed immediately after stopping exercise to stimulate muscle protein and tendon collagen turnover within 1 h.

  17. Protein turnover, amino acid requirements and recommendations for athletes and active populations

    Directory of Open Access Journals (Sweden)

    J.R. Poortmans

    2012-10-01

    Full Text Available Skeletal muscle is the major deposit of protein molecules. As for any cell or tissue, total muscle protein reflects a dynamic turnover between net protein synthesis and degradation. Noninvasive and invasive techniques have been applied to determine amino acid catabolism and muscle protein building at rest, during exercise and during the recovery period after a single experiment or training sessions. Stable isotopic tracers (13C-lysine, 15N-glycine, ²H5-phenylalanine and arteriovenous differences have been used in studies of skeletal muscle and collagen tissues under resting and exercise conditions. There are different fractional synthesis rates in skeletal muscle and tendon tissues, but there is no major difference between collagen and myofibrillar protein synthesis. Strenuous exercise provokes increased proteolysis and decreased protein synthesis, the opposite occurring during the recovery period. Individuals who exercise respond differently when resistance and endurance types of contractions are compared. Endurance exercise induces a greater oxidative capacity (enzymes compared to resistance exercise, which induces fiber hypertrophy (myofibrils. Nitrogen balance (difference between protein intake and protein degradation for athletes is usually balanced when the intake of protein reaches 1.2 g·kg-1·day-1 compared to 0.8 g·kg-1·day-1 in resting individuals. Muscular activities promote a cascade of signals leading to the stimulation of eukaryotic initiation of myofibrillar protein synthesis. As suggested in several publications, a bolus of 15-20 g protein (from skimmed milk or whey proteins and carbohydrate (± 30 g maltodextrine drinks is needed immediately after stopping exercise to stimulate muscle protein and tendon collagen turnover within 1 h.

  18. Host-Derived Sialic Acids Are an Important Nutrient Source Required for Optimal Bacterial Fitness In Vivo

    Directory of Open Access Journals (Sweden)

    Nathan D. McDonald

    2016-04-01

    Full Text Available A major challenge facing bacterial intestinal pathogens is competition for nutrient sources with the host microbiota. Vibrio cholerae is an intestinal pathogen that causes cholera, which affects millions each year; however, our knowledge of its nutritional requirements in the intestinal milieu is limited. In this study, we demonstrated that V. cholerae can grow efficiently on intestinal mucus and its component sialic acids and that a tripartite ATP-independent periplasmic SiaPQM strain, transporter-deficient mutant NC1777, was attenuated for colonization using a streptomycin-pretreated adult mouse model. In in vivo competition assays, NC1777 was significantly outcompeted for up to 3 days postinfection. NC1777 was also significantly outcompeted in in vitro competition assays in M9 minimal medium supplemented with intestinal mucus, indicating that sialic acid uptake is essential for fitness. Phylogenetic analyses demonstrated that the ability to utilize sialic acid was distributed among 452 bacterial species from eight phyla. The majority of species belonged to four phyla, Actinobacteria (members of Actinobacillus, Corynebacterium, Mycoplasma, and Streptomyces, Bacteroidetes (mainly Bacteroides, Capnocytophaga, and Prevotella, Firmicutes (members of Streptococcus, Staphylococcus, Clostridium, and Lactobacillus, and Proteobacteria (including Escherichia, Shigella, Salmonella, Citrobacter, Haemophilus, Klebsiella, Pasteurella, Photobacterium, Vibrio, and Yersinia species, mostly commensals and/or pathogens. Overall, our data demonstrate that the ability to take up host-derived sugars and sialic acid specifically allows V. cholerae a competitive advantage in intestinal colonization and that this is a trait that is sporadic in its occurrence and phylogenetic distribution and ancestral in some genera but horizontally acquired in others.

  19. Conserved amino acid motifs from the novel Piv/MooV family of transposases and site-specific recombinases are required for catalysis of DNA inversion by Piv.

    Science.gov (United States)

    Tobiason, D M; Buchner, J M; Thiel, W H; Gernert, K M; Karls, A C

    2001-02-01

    Piv, a site-specific invertase from Moraxella lacunata, exhibits amino acid homology with the transposases of the IS110/IS492 family of insertion elements. The functions of conserved amino acid motifs that define this novel family of both transposases and site-specific recombinases (Piv/MooV family) were examined by mutagenesis of fully conserved amino acids within each motif in Piv. All Piv mutants altered in conserved residues were defective for in vivo inversion of the M. lacunata invertible DNA segment, but competent for in vivo binding to Piv DNA recognition sequences. Although the primary amino acid sequences of the Piv/MooV recombinases do not contain a conserved DDE motif, which defines the retroviral integrase/transposase (IN/Tnps) family, the predicted secondary structural elements of Piv align well with those of the IN/Tnps for which crystal structures have been determined. Molecular modelling of Piv based on these alignments predicts that E59, conserved as either E or D in the Piv/MooV family, forms a catalytic pocket with the conserved D9 and D101 residues. Analysis of Piv E59G confirms a role for E59 in catalysis of inversion. These results suggest that Piv and the related IS110/IS492 transposases mediate DNA recombination by a common mechanism involving a catalytic DED or DDD motif.

  20. A requirement of TolC and MDR efflux pumps for acid adaptation and GadAB induction in Escherichia coli.

    Directory of Open Access Journals (Sweden)

    Kari N W Deininger

    Full Text Available BACKGROUND: The TolC outer membrane channel is a key component of several multidrug resistance (MDR efflux pumps driven by H(+ transport in Escherichia coli. While tolC expression is under the regulation of the EvgA-Gad acid resistance regulon, the role of TolC in growth at low pH and extreme-acid survival is unknown. METHODS AND PRINCIPAL FINDINGS: TolC was required for extreme-acid survival (pH 2 of strain W3110 grown aerobically to stationary phase. A tolC deletion decreased extreme-acid survival (acid resistance of aerated pH 7.0-grown cells by 10(5-fold and of pH 5.5-grown cells by 10-fold. The requirement was specific for acid resistance since a tolC defect had no effect on aerobic survival in extreme base (pH 10. TolC was required for expression of glutamate decarboxylase (GadA, GadB, a key component of glutamate-dependent acid resistance (Gad. TolC was also required for maximal exponential growth of E. coli K-12 W3110, in LBK medium buffered at pH 4.5-6.0, but not at pH 6.5-8.5. The TolC growth requirement in moderate acid was independent of Gad. TolC-associated pump components EmrB and MdtB contributed to survival in extreme acid (pH 2, but were not required for growth at pH 5. A mutant lacking the known TolC-associated efflux pumps (acrB, acrD, emrB, emrY, macB, mdtC, mdtF, acrEF showed no growth defect at acidic pH and a relatively small decrease in extreme-acid survival when pre-grown at pH 5.5. CONCLUSIONS: TolC and proton-driven MDR efflux pump components EmrB and MdtB contribute to E. coli survival in extreme acid and TolC is required for maximal growth rates below pH 6.5. The TolC enhancement of extreme-acid survival includes Gad induction, but TolC-dependent growth rates below pH 6.5 do not involve Gad. That MDR resistance can enhance growth and survival in acid is an important consideration for enteric organisms passing through the acidic stomach.

  1. Non-equivalence of key positively charged residues of the free fatty acid 2 receptor in the recognition and function of agonist versus antagonist ligands

    DEFF Research Database (Denmark)

    Sergeev, Eugenia; Hojgaard Hansen, Anders; Pandey, Sunil K

    2016-01-01

    Short chain fatty acids (SCFAs) are produced in the gut by bacterial fermentation of poorly digested carbohydrates. A key mediator of their actions is the G protein-coupled Free Fatty Acid 2 (FFA2) receptor and this has been suggested as a therapeutic target for the treatment of both metabolic an...

  2. RESIDUAL RISK ASSESSMENT: ETHYLENE OXIDE ...

    Science.gov (United States)

    This document describes the residual risk assessment for the Ethylene Oxide Commercial Sterilization source category. For stationary sources, section 112 (f) of the Clean Air Act requires EPA to assess risks to human health and the environment following implementation of technology-based control standards. If these technology-based control standards do not provide an ample margin of safety, then EPA is required to promulgate addtional standards. This document describes the methodology and results of the residual risk assessment performed for the Ethylene Oxide Commercial Sterilization source category. The results of this analyiss will assist EPA in determining whether a residual risk rule for this source category is appropriate.

  3. Distinct functional domains within the acidic cluster of tegument protein pp28 required for trafficking and cytoplasmic envelopment of human cytomegalovirus.

    Science.gov (United States)

    Seo, Jun-Young; Jeon, Hyejin; Hong, Sookyung; Britt, William J

    2016-10-01

    Human cytomegalovirus UL99-encoded tegument protein pp28 contains a 16 aa acidic cluster that is required for pp28 trafficking to the assembly compartment (AC) and the virus assembly. However, functional signals within the acidic cluster of pp28 remain undefined. Here, we demonstrated that an acidic cluster rather than specific sorting signals was required for trafficking to the AC. Recombinant viruses with chimeric pp28 proteins expressing non-native acidic clusters exhibited delayed viral growth kinetics and decreased production of infectious virus, indicating that the native acidic cluster of pp28 was essential for wild-type virus assembly. These results suggested that the acidic cluster of pp28 has distinct functional domains required for trafficking and for efficient virus assembly. The first half (aa 44-50) of the acidic cluster was sufficient for pp28 trafficking, whereas the native acidic cluster consisting of aa 51-59 was required for the assembly of wild-type levels of infectious virus.

  4. Identification of hormone-interacting amino acid residues within the steroid-binding domain of the glucocorticoid receptor in relation to other steroid hormone receptors

    International Nuclear Information System (INIS)

    Carlstedt-Duke, J.; Stroemstedt, P.E.; Persson, B.; Cederlund, E.; Gustafsson, J.A.; Joernvall, H.

    1988-01-01

    Purified rat liver glucocorticoid receptor was covalently charged with [ 3 H]glucocorticoid by photoaffinity labeling (UV irradiation of [ 3 H]triamcinolone acetonide-glucocorticoid receptor) or affinity labeling (incubation with [ 3 H]dexamethasone mesylate). After labeling, separate samples of the denatured receptor were cleaved with trypsin (directly or after prior succinylation), chymotrypsin, and cyanogen bromide. Labeled residues in the peptides obtained were identified by radiosequence analysis. The peaks of radioactivity corresponded to Met-622 and Cys-754 after photoaffinity labeling with [ 3 H]triamcinolone acetonide and Cys-656 after affinity labeling with [ 3 H]dexamethasone mesylate. The labeled residues are all positioned within hydrophobic segments of the steroid-binding domain. The patterns of hydropathy and secondary structure for the glucocorticoid receptor are highly similar to those for the progestin receptor and similar but less so to those for the estrogen receptor and to those for c-erb A

  5. Consensus of sample-balanced classifiers for identifying ligand-binding residue by co-evolutionary physicochemical characteristics of amino acids

    KAUST Repository

    Chen, Peng

    2013-01-01

    Protein-ligand binding is an important mechanism for some proteins to perform their functions, and those binding sites are the residues of proteins that physically bind to ligands. So far, the state-of-the-art methods search for similar, known structures of the query and predict the binding sites based on the solved structures. However, such structural information is not commonly available. In this paper, we propose a sequence-based approach to identify protein-ligand binding residues. Due to the highly imbalanced samples between the ligand-binding sites and non ligand-binding sites, we constructed several balanced data sets, for each of which a random forest (RF)-based classifier was trained. The ensemble of these RF classifiers formed a sequence-based protein-ligand binding site predictor. Experimental results on CASP9 targets demonstrated that our method compared favorably with the state-of-the-art. © Springer-Verlag Berlin Heidelberg 2013.

  6. Casein kinase 2 down-regulation and activation by polybasic peptides are mediated by acidic residues in the 55-64 region of the beta-subunit. A study with calmodulin as phosphorylatable substrate

    DEFF Research Database (Denmark)

    Meggio, F; Boldyreff, B; Issinger, O G

    1994-01-01

    to substitute for wild-type beta-subunit as a suppressor of activity toward calmodulin. The only mutations that reduced the ability of the beta-subunit to suppress calmodulin phosphorylation activity, though being compatible with normal reconstitution of CK2 holoenzyme, were those affecting Asp55, Glu57...... are conversely ineffective. The latent "calmodulin kinase" activity of CK2 can also be specifically unmasked by a peptide (alpha[66-86]) reproducing a basic insert of the catalytic subunit. This effect is reversed by equimolar addition of a peptide (beta[55-71]) including the 55-64 acidic stretch of the beta......-subunit. Comparable polylysine stimulation was observed with the holoenzymes reconstituted with either beta wt or the beta mutants capable of assembling with the alpha-subunit, with the notable exception of those bearing Ala substitutions for acidic residues at positions 55, 57, and 59-61. These were nearly...

  7. Influence of amino acid residues near the active site of cytochrome P450 from Bacillus megaterium on the selectivity of n-octane oxidation to octanol regioisomers

    Science.gov (United States)

    Miyaji, Akimitsu; Baba, Toshihide

    2017-09-01

    A mutant of cytochrome P450 from Bacillus megaterium (CYP450BM-3) was prepared by replacing two alanine residues around active site of the enzyme, alanine 328 and alanine 82, with leucine and tryptophan, respectively. The CYP450BM-3 mutant produced 2-octanol selectively from n-octane under atmospheric temperature and pressure; its selectivity was 74%. Furthermore, the mutant produced 1-octanol, which is not produced by wild-type enzyme.

  8. Structural basis for new pattern of conserved amino acid residues related to chitin-binding in the antifungal peptide from the coconut rhinoceros beetle Oryctes rhinoceros.

    Science.gov (United States)

    Hemmi, Hikaru; Ishibashi, Jun; Tomie, Tetsuya; Yamakawa, Minoru

    2003-06-20

    Scarabaecin isolated from hemolymph of the coconut rhinoceros beetle Oryctes rhinoceros is a 36-residue polypeptide that has antifungal activity. The solution structure of scarabaecin has been determined from twodimensional 1H NMR spectroscopic data and hybrid distance geometry-simulated annealing protocol calculation. Based on 492 interproton and 10 hydrogen-bonding distance restraints and 36 dihedral angle restraints, we obtained 20 structures. The average backbone root-mean-square deviation for residues 4-35 is 0.728 +/- 0.217 A from the mean structure. The solution structure consists of a two-stranded antiparallel beta-sheet connected by a type-I beta-turn after a short helical turn. All secondary structures and a conserved disulfide bond are located in the C-terminal half of the peptide, residues 18-36. Overall folding is stabilized by a combination of a disulfide bond, seven hydrogen bonds, and numerous hydrophobic interactions. The structural motif of the C-terminal half shares a significant tertiary structural similarity with chitin-binding domains of plant and invertebrate chitin-binding proteins, even though scarabaecin has no overall sequence similarity to other peptide/polypeptides including chitin-binding proteins. The length of its primary structure, the number of disulfide bonds, and the pattern of conserved functional residues binding to chitin in scarabaecin differ from those of chitin-binding proteins in other invertebrates and plants, suggesting that scarabaecin does not share a common ancestor with them. These results are thought to provide further strong experimental evidence to the hypothesis that chitin-binding proteins of invertebrates and plants are correlated by a convergent evolution process.

  9. Endogenous salicylic acid is required for promoting cadmium tolerance of Arabidopsis by modulating glutathione metabolisms

    International Nuclear Information System (INIS)

    Guo, Bin; Liu, Chen; Li, Hua; Yi, Keke; Ding, Nengfei; Li, Ningyu; Lin, Yicheng; Fu, Qinglin

    2016-01-01

    Highlights: • The role of endogenous SA in mediating Cd tolerance was explored using sid2 mutants. • Cd stress induces SA accumulation in a SID2 dependent way. • Depletion of SA causes negative effects on Cd tolerance. • Endogenous SA is required for promoting Cd tolerance by modulating GSH metabolism. • Possible mode of SA signaling through GR/GSH pathway under Cd toxicity was discussed. - Abstract: A few studies with NahG transgenic lines of Arabidopsis show that depletion of SA enhances cadmium (Cd) tolerance. However, it remains some uncertainties that the defence signaling may be a result of catechol accumulation in NahG transgenic lines but not SA deficiency. Here, we conducted a set of hydroponic assays with another SA-deficient mutant sid2 to examine the endogenous roles of SA in Cd tolerance, especially focusing on the glutathione (GSH) cycling. Our results showed that reduced SA resulted in negative effects on Cd tolerance, including decreased Fe uptake and chlorophyll concentration, aggravation of oxidative damage and growth inhibition. Cd exposure significantly increased SA concentration in wild-type leaves, but did not affect it in sid2 mutants. Depletion of SA did not disturb the Cd uptake in either roots or shoots. The reduced Cd tolerance in sid2 mutants is due to the lowered GSH status, which is associated with the decreased expression of serine acetyltransferase along with a decline in contents of non-protein thiols, phytochelatins, and the lowered transcription and activities of glutathione reductase1 (GR1) which reduced GSH regeneration. Finally, the possible mode of SA signaling through the GR/GSH pathway during Cd exposure is discussed.

  10. Endogenous salicylic acid is required for promoting cadmium tolerance of Arabidopsis by modulating glutathione metabolisms

    Energy Technology Data Exchange (ETDEWEB)

    Guo, Bin, E-mail: ndgb@163.com [Institute of Environment, Resource, Soil and Fertilizer, Zhejiang Academy of Agricultural Sciences, Geological Research Center For Agricultural Applications, China Geological Survey, Hangzhou (China); Liu, Chen; Li, Hua [Institute of Environment, Resource, Soil and Fertilizer, Zhejiang Academy of Agricultural Sciences, Geological Research Center For Agricultural Applications, China Geological Survey, Hangzhou (China); Yi, Keke [Institute of Virology and Biotechnology, Zhejiang Academy of Agricultural Sciences, Hangzhou (China); Ding, Nengfei; Li, Ningyu; Lin, Yicheng [Institute of Environment, Resource, Soil and Fertilizer, Zhejiang Academy of Agricultural Sciences, Geological Research Center For Agricultural Applications, China Geological Survey, Hangzhou (China); Fu, Qinglin, E-mail: fuql161@yahoo.com.cn [Institute of Environment, Resource, Soil and Fertilizer, Zhejiang Academy of Agricultural Sciences, Geological Research Center For Agricultural Applications, China Geological Survey, Hangzhou (China)

    2016-10-05

    Highlights: • The role of endogenous SA in mediating Cd tolerance was explored using sid2 mutants. • Cd stress induces SA accumulation in a SID2 dependent way. • Depletion of SA causes negative effects on Cd tolerance. • Endogenous SA is required for promoting Cd tolerance by modulating GSH metabolism. • Possible mode of SA signaling through GR/GSH pathway under Cd toxicity was discussed. - Abstract: A few studies with NahG transgenic lines of Arabidopsis show that depletion of SA enhances cadmium (Cd) tolerance. However, it remains some uncertainties that the defence signaling may be a result of catechol accumulation in NahG transgenic lines but not SA deficiency. Here, we conducted a set of hydroponic assays with another SA-deficient mutant sid2 to examine the endogenous roles of SA in Cd tolerance, especially focusing on the glutathione (GSH) cycling. Our results showed that reduced SA resulted in negative effects on Cd tolerance, including decreased Fe uptake and chlorophyll concentration, aggravation of oxidative damage and growth inhibition. Cd exposure significantly increased SA concentration in wild-type leaves, but did not affect it in sid2 mutants. Depletion of SA did not disturb the Cd uptake in either roots or shoots. The reduced Cd tolerance in sid2 mutants is due to the lowered GSH status, which is associated with the decreased expression of serine acetyltransferase along with a decline in contents of non-protein thiols, phytochelatins, and the lowered transcription and activities of glutathione reductase1 (GR1) which reduced GSH regeneration. Finally, the possible mode of SA signaling through the GR/GSH pathway during Cd exposure is discussed.

  11. Identification of a highly conserved valine-glycine-phenylalanine amino acid triplet required for HIV-1 Nef function

    Directory of Open Access Journals (Sweden)

    Meuwissen Pieter J

    2012-04-01

    Full Text Available Abstract Background The Nef protein of HIV facilitates virus replication and disease progression in infected patients. This role as pathogenesis factor depends on several genetically separable Nef functions that are mediated by interactions of highly conserved protein-protein interaction motifs with different host cell proteins. By studying the functionality of a series of nef alleles from clinical isolates, we identified a dysfunctional HIV group O Nef in which a highly conserved valine-glycine-phenylalanine (VGF region, which links a preceding acidic cluster with the following proline-rich motif into an amphipathic surface was deleted. In this study, we aimed to study the functional importance of this VGF region. Results The dysfunctional HIV group O8 nef allele was restored to the consensus sequence, and mutants of canonical (NL4.3, NA-7, SF2 and non-canonical (B2 and C1422 HIV-1 group M nef alleles were generated in which the amino acids of the VGF region were changed into alanines (VGF→AAA and tested for their capacity to interfere with surface receptor trafficking, signal transduction and enhancement of viral replication and infectivity. We found the VGF motif, and each individual amino acid of this motif, to be critical for downregulation of MHC-I and CXCR4. Moreover, Nef’s association with the cellular p21-activated kinase 2 (PAK2, the resulting deregulation of cofilin and inhibition of host cell actin remodeling, and targeting of Lck kinase to the trans-golgi-network (TGN were affected as well. Of particular interest, VGF integrity was essential for Nef-mediated enhancement of HIV virion infectivity and HIV replication in peripheral blood lymphocytes. For targeting of Lck kinase to the TGN and viral infectivity, especially the phenylalanine of the triplet was essential. At the molecular level, the VGF motif was required for the physical interaction of the adjacent proline-rich motif with Hck. Conclusion Based on these findings, we

  12. Fatty acid profile in milk from goats, Capra aegagrus hircus, exposed to perchlorate and its relationship with perchlorate residues in human milk.

    Science.gov (United States)

    Cheng, Qiuqiong; Smith, Ernest E; Kirk, Andrea B; Liu, Fujun; Boylan, Lee Mallory; McCarty, Michael E; Hart, Sybil; Dong, Linxia; Cobb, George P; Jackson, W Andrew; Anderson, Todd A

    2007-10-01

    Polyunsaturated fatty acids (PUFA) in milk are vital for normal growth and development of infant mammals. Changes in fatty acid composition were observed in milk fat from goats dosed with perchlorate (0.1 and 1 mg/kg body weight/day) for 31 days, but the effect was not persistent. Adaptation may be induced in these goats to compensate for the perchlorate effect. In an analysis of fatty acid composition in human milk samples, a weak negative correlation was observed between perchlorate concentrations and total PUFA in 38 human milk samples.

  13. Residual nilpotence and residual solubility of groups

    International Nuclear Information System (INIS)

    Mikhailov, R V

    2005-01-01

    The properties of the residual nilpotence and the residual solubility of groups are studied. The main objects under investigation are the class of residually nilpotent groups such that each central extension of these groups is also residually nilpotent and the class of residually soluble groups such that each Abelian extension of these groups is residually soluble. Various examples of groups not belonging to these classes are constructed by homological methods and methods of the theory of modules over group rings. Several applications of the theory under consideration are presented and problems concerning the residual nilpotence of one-relator groups are considered.

  14. High power valve regulated lead-acid batteries for new vehicle requirements

    Science.gov (United States)

    Trinidad, Francisco; Sáez, Francisco; Valenciano, Jesús

    The performance of high power VRLA ORBITAL™ batteries is presented. These batteries have been designed with isolated cylindrical cells, providing high reliability to the recombination process, while maintaining, at the same time, a very high compression (>80 kPa) over the life of the battery. Hence, the resulting VRLA modules combine a high rate capability with a very good cycle performance. Two different electrochemically active material compositions have been developed: high porosity and low porosity for starting and deep cycle applications, respectively (depending on the power demand and depth of discharge). Although, the initial performance of the starting version is higher, after a few cycles the active material of the deep cycle version is fully developed, and this achieves the same high rate capability. Both types are capable of supplying the necessary reliability for cranking at the lowest temperature (-40°C). Specific power of over 500 W/kg is achievable at a much lower cost than for nickel-metal hydride systems. Apart from the initial performance, an impressive behaviour of the cycling version has been found in deep cycle applications, due to the highly compressed and high density active material. When submitted to continuous discharge-charge cycles at 75% (IEC 896-2 specification) and 100% (BCI deep cycle) DoD, it has been found that the batteries are still healthy after more than 1000 and 700 cycles, respectively. However, it has been proven that the application of an IUi algorithm (up to 110% of overcharging) with a small constant current charging period at the end of the charge is absolutely necessary to achieve the above results. Without the final boosting period, the cycle life of the battery could be substantially shortened. The high specific power and reliability observed in the tests carried out, would allow ORBITAL™ batteries to comply with the more demanding requirements that are being introduced in conventional and future hybrid electric

  15. Increase in tartrate-resistant acid phosphatase of bone at the early stage of ascorbic acid deficiency in the ascorbate-requiring Osteogenic Disorder Shionogi (ODS) rat.

    Science.gov (United States)

    Goto, A; Tsukamoto, I

    2003-08-01

    The effect of ascorbic acid deficiency on bone metabolism was evaluated using the ascorbate-requiring Osteogenic Disorder Shionogi (ODS) rat model. Ascorbic acid (Asc)-deficient rats gained body weight in a manner similar to Asc-supplemented rats (control) during 3 weeks, but began to lose weight during the 4th week of Asc deficiency. The tartrate-resistant acid phosphatase (TRAP) activity in serum increased to about 2-fold the control value in the rats fed the Asc-free diet for 2, 3, and 4 weeks (AscD2, AscD3, and AscD4), while a decrease in the alkaline phosphatase (ALP) activity was observed only in AscD4 rats. The serum pyridinoline cross-linked carboxyterminal telopeptide of type I collagen (ICTP) level significantly increased to 1.3-, 1.4-, and 1.9-fold of that in the controls in AscD2, D3, and D4, respectively. The ALP activity in the distal femur was unchanged in AscD1, D2, and D3, but decreased to 50% of the control level in AscD4 rats. The TRAP activity in the distal femur increased to about 2-fold of that in the controls in the AscD2 and D3 and decreased to the control level in the AscD4 rats. The amount of hydroxyproline in the distal femur significantly decreased to about 80%, 70%, and 60% of the control in AscD2, D3, and D4 rats, respectively. These decreases were associated with a similar reduction in the calcium content of the distal femur. Histochemical analysis of the distal femur showed an increase in TRAP-positive cells in AscD2 and AscD3 rats and a decrease in the trabecular bone in AscD2, D3, and D4 rats. These results suggested that a deficiency of Asc stimulated bone resorption at an early stage, followed by a decrease in bone formation in mature ODS rats which already had a well-developed collagen matrix and fully differentiated osteoblasts.

  16. Identification of genes required for secretion of the Francisella oxidative burst-inhibiting acid phosphatase AcpA

    Directory of Open Access Journals (Sweden)

    John S Gunn

    2016-04-01

    Full Text Available Francisella tularensis is a Tier 1 bioterror threat and the intracellular pathogen responsible for tularemia in humans and animals. Upon entry into the host, Francisella uses multiple mechanisms to evade killing. Our previous studies have shown that after entering its primary cellular host, the macrophage, Francisella immediately suppresses the oxidative burst by secreting a series of acid phosphatases including AcpA-B-C and HapA, thereby evading the innate immune response of the macrophage and enhancing survival and further infection. However, the mechanism of acid phosphatase secretion by Francisella is still unknown. In this study, we screened for genes required for AcpA secretion in Francisella. We initially demonstrated that the known secretion systems, the putative Francisella-pathogenicity island (FPI-encoded Type VI secretion system and the Type IV pili, do not secrete AcpA. Using random transposon mutagenesis in conjunction with ELISA, Western blotting and acid phosphatase enzymatic assays, a transposon library of 5450 mutants was screened for strains with a minimum 1.5-fold decrease in secreted (culture supernatant AcpA, but no defect in cytosolic AcpA. Three mutants with decreased supernatant AcpA were identified. The transposon insertion sites of these mutants were revealed by direct genomic sequencing or inverse-PCR and sequencing. One of these mutants has a severe defect in AcpA secretion (at least 85% decrease and is a predicted hypothetical inner membrane protein. Interestingly, this mutant also affected the secretion of the FPI-encoded protein, VgrG. Thus, this screen identified novel protein secretion factors involved in the subversion of host defenses.

  17. Low oleic acid-derived repression of jasmonic acid-inducible defense responses requires the WRKY50 and WRKY51 proteins

    Science.gov (United States)

    Signaling induced upon a reduction in oleic acid (18:1) levels simultaneously up-regulates salicylic acid (SA)-mediated responses and inhibits jasmonic acid (JA)-inducible defenses, resulting in enhanced resistance to biotrophs but increased susceptibility to necrotrophs. SA and the signaling compon...

  18. Phospho-Rasputin Stabilization by Sec16 Is Required for Stress Granule Formation upon Amino Acid Starvation

    Directory of Open Access Journals (Sweden)

    Angelica Aguilera-Gomez

    2017-07-01

    Full Text Available Most cellular stresses induce protein translation inhibition and stress granule formation. Here, using Drosophila S2 cells, we investigate the role of G3BP/Rasputin in this process. In contrast to arsenite treatment, where dephosphorylated Ser142 Rasputin is recruited to stress granules, we find that, upon amino acid starvation, only the phosphorylated Ser142 form is recruited. Furthermore, we identify Sec16, a component of the endoplasmic reticulum exit site, as a Rasputin interactor and stabilizer. Sec16 depletion results in Rasputin degradation and inhibition of stress granule formation. However, in the absence of Sec16, pharmacological stabilization of Rasputin is not enough to rescue the assembly of stress granules. This is because Sec16 specifically interacts with phosphorylated Ser142 Rasputin, the form required for stress granule formation upon amino acid starvation. Taken together, these results demonstrate that stress granule formation is fine-tuned by specific signaling cues that are unique to each stress. These results also expand the role of Sec16 as a stress response protein.

  19. Phospho-Rasputin Stabilization by Sec16 Is Required for Stress Granule Formation upon Amino Acid Starvation.

    Science.gov (United States)

    Aguilera-Gomez, Angelica; Zacharogianni, Margarita; van Oorschot, Marinke M; Genau, Heide; Grond, Rianne; Veenendaal, Tineke; Sinsimer, Kristina S; Gavis, Elizabeth R; Behrends, Christian; Rabouille, Catherine

    2017-07-25

    Most cellular stresses induce protein translation inhibition and stress granule formation. Here, using Drosophila S2 cells, we investigate the role of G3BP/Rasputin in this process. In contrast to arsenite treatment, where dephosphorylated Ser142 Rasputin is recruited to stress granules, we find that, upon amino acid starvation, only the phosphorylated Ser142 form is recruited. Furthermore, we identify Sec16, a component of the endoplasmic reticulum exit site, as a Rasputin interactor and stabilizer. Sec16 depletion results in Rasputin degradation and inhibition of stress granule formation. However, in the absence of Sec16, pharmacological stabilization of Rasputin is not enough to rescue the assembly of stress granules. This is because Sec16 specifically interacts with phosphorylated Ser142 Rasputin, the form required for stress granule formation upon amino acid starvation. Taken together, these results demonstrate that stress granule formation is fine-tuned by specific signaling cues that are unique to each stress. These results also expand the role of Sec16 as a stress response protein. Copyright © 2017 The Author(s). Published by Elsevier Inc. All rights reserved.

  20. Study of radionuclide leaching from the residues of K Basin sludge dissolution

    International Nuclear Information System (INIS)

    Bechtold, D.B.

    1998-01-01

    The sludges remaining in the K Basins after removal of the spent N Reactor nuclear fuel will be conditioned for disposal. After conditioning, an acid-insoluble residue will remain that may require further leaching to properly condition it for disposal. This document presents a literature study to identify and recommend one or more chemical leaching treatments for laboratory testing, based on the likely compositions of the residues. The processes identified are a nitric acid cerate leach, a silver-catalyzed persulfate leach, a nitric hydrofluoric acid leach, an oxalic citric acid reactor decontamination leach, a nitric hydrochloric acid leach, a ammonium fluoride nitrate leach, and a HEOPA formate dehydesulfoxylate leach. All processes except the last two are recommended for testing in that order

  1. Actinide recovery from pyrochemical residues

    International Nuclear Information System (INIS)

    Avens, L.R.; Clifton, D.G.; Vigil, A.R.

    1984-01-01

    A new process for recovery of plutonium and americium from pyrochemical waste has been demonstrated. It is based on chloride solution anion exchange at low acidity, which eliminates corrosive HCl fumes. Developmental experiments of the process flowsheet concentrated on molten salt extraction (MSE) residues and gave >95% plutonium and >90% americium recovery. The recovered plutonium contained 6 = from high chloride-low acid solution. Americium and other metals are washed from the ion exchange column with 1N HNO 3 -4.8M NaCl. The plutonium is recovered, after elution, via hydroxide precipitation, while the americium is recovered via NaHCO 3 precipitation. All filtrates from the process are discardable as low-level contaminated waste. Production-scale experiments are now in progress for MSE residues. Flow sheets for actinide recovery from electrorefining and direct oxide reduction residues are presented and discussed

  2. Total Sulfur Amino Acid Requirements Are Not Altered in Children with Chronic Renal Insufficiency, but Minimum Methionine Needs Are Increased.

    Science.gov (United States)

    Elango, Rajavel; Humayun, Mohammad A; Turner, Justine M; Rafii, Mahroukh; Langos, Veronika; Ball, Ronald O; Pencharz, Paul B

    2017-10-01

    Background: The total sulfur amino acid (TSAA) and minimum Met requirements have been previously determined in healthy children. TSAA metabolism is altered in kidney disease. Whether TSAA requirements are altered in children with chronic renal insufficiency (CRI) is unknown. Objective: We sought to determine the TSAA (Met in the absence of Cys) requirements and minimum Met (in the presence of excess Cys) requirements in children with CRI. Methods: Five children (4 boys, 1 girl) aged 10 ± 2.6 y with CRI were randomly assigned to receive graded intakes of Met (0, 5, 10, 15, 25, and 35 mg · kg -1 · d -1 ) with no Cys in the diet. Four of the children (3 boys, 1 girl) were then randomly assigned to receive graded dietary intakes of Met (0, 2.5, 5, 7.5, 10, and 15 mg · kg -1 · d -1 ) with 21 mg · kg -1 · d -1 Cys. The mean TSAA and minimum Met requirements were determined by measuring the oxidation of l-[1- 13 C]Phe to 13 CO 2 (F 13 CO 2 ). A 2-phase linear-regression crossover analysis of the F 13 CO 2 data identified a breakpoint at minimal F 13 CO 2 Urine samples collected from all study days and from previous studies of healthy children were measured for sulfur metabolites. Results: The mean and population-safe (upper 95% CI) intakes of TSAA and minimum Met in children with CRI were determined to be 12.6 and 15.9 mg · kg -1 · d -1 and 7.3 and 10.9 mg · kg -1 · d -1 , respectively. In healthy school-aged children the mean and upper 95% CI intakes of TSAA and minimum Met were determined to be 12.9 and 17.2 mg · kg -1 · d -1 and 5.8 and 7.3 mg · kg -1 · d -1 , respectively. A comparison of the minimum Met requirements between healthy children and children with CRI indicated significant ( P < 0.05) differences. Conclusion: These results suggest that children with CRI have a similar mean and population-safe TSAA to that of healthy children, suggesting adequate Cys synthesis via transsulfuration, but higher minimum Met requirement, suggesting reduced

  3. Analysis of Amino Acid Residues of Potential Importance for Phosphati-dylserine Specificity of P4-type ATPase ATP8A2

    DEFF Research Database (Denmark)

    Mogensen, Louise; Vestergaard, Anna Lindeløv; Mikkelsen, Stine

    The asymmetric structure of the plasma membrane is maintained through internalization of phos-pholipids by the family of P4-ATPases by a poorly characterized mechanism. Studies in yeast point towards a non-classical pathway involving important residues of a two-gate mechanism [1]. Glycine-230...... 302 of ATP8A2 with alanine (N302A), tyrosine (N302Y) and serine (N302S). Furthermore, a triple mutant of ATP8A2 (Q95GQ96AN302S) was studied to reveal any cooperativity between the two gates, as observed in yeast [1]. The affinities of the mutants for phosphatidylserine and phosphatidylethanolamine...

  4. Effect of routine preoperative fasting on residual gastric volume and ...

    African Journals Online (AJOL)

    2016-02-10

    Feb 10, 2016 ... Key words: Fasting, myomectomy, pH, residual gastric volume. Date of Acceptance: ... gastric volume and acid in patients undergoing myomectomy. Niger J Clin ..... of gastric residual volume: A simulated, controlled study.

  5. Metabolism-oriented amino acid requirement determination by means of the catabolic rates of 14C- and 15N-labelled lysine under maintenance

    International Nuclear Information System (INIS)

    Simon, O.; Bergner, H.; Adam, K.

    1977-01-01

    Male Wistar rats (of 60 g live weight) allotted in 10 groups were fed diets with gradually increasing lysine levels ranging from 1.4 to 7.4 g lysine/16 g N. Feed intake was restricted so much that the experimental animals did not change their live weights during the last 3 days of the 8-day experimental period. On the 7the experimental day, 4 animals of each group were injected, i. p. 14 C-L-lysine, the 14 CO 2 -excretion being subsequently measured over a period of 2 hours. On the next day, 6 animals of each group were applied an i. p. injection of 15 N-L-lysine, the urine being collected over the following 24-hour period to measure the 15 N-frequency. Applying both labelling methods, an increased catabolisation of the amino acid was observed after the metabolically necessary lysine requirement had been covered. The methods are very sensitive and revealed, under the experimental conditions chosen, a lysine requirement coverage of about 3 g lysine/16 g N. The possibility of using also 15 N-labelled compounds in the metabolism-oriented amino acid requirement determination is likely to facilitate the transfer of the methodology to farm animals would thus allow to study the amino acid requirement of man. The metabolism-oriented amino acid requirement determination will likewise allow to estimate exact amino acid requirement data under conditions that cannot be rated on the basis of productive yields. (author)

  6. Revk - a Tool for the Fulfilment of Requirements from National Rules for Tracking and Documentation of Radioactive Residual Material and Radioactive Waste

    International Nuclear Information System (INIS)

    Hartmann, B.; Haeger, M.; Gruendler, D.

    2006-01-01

    According to the German Radiation Protection Ordinance treatment, storage, whereabouts of radioactive material etc. have to be documented. Due to legal requirements an electronic documentation system for radioactive waste has to be installed. Within the framework of the currently largest decommissioning project of nuclear facilities by Energiewerke Nord GmbH, a material flow-waste tracking and control system (ReVK) has been developed, tailored to the special needs of the decommissioning of nuclear facilities. With this system it is possible to record radioactive materials which can be released after treatment or decay storage for restricted and unrestricted utilization. Radioactive waste meant for final storage can be registered and documented as well. Based on ORACLE, ReVK is a client/server data base system with the following modules: 1. data registration, 2. transport management, 3. waste tracking, 4. storage management, 5. container management, 6. reporting, 7. activity calculation, 8. examination of technical acceptance criteria for storages and final repositories. Furthermore ReVK provides a multitude of add-ons to meet special user needs, which enlarge the spectrum of application enormously. ReVK is validated and qualified, accepted by experts and authorities and fulfils the requirements for a radioactive waste documentation system. (authors)

  7. Protein Requirements Are Elevated in Endurance Athletes after Exercise as Determined by the Indicator Amino Acid Oxidation Method.

    Directory of Open Access Journals (Sweden)

    Hiroyuki Kato

    Full Text Available A higher protein intake has been recommended for endurance athletes compared with healthy non-exercising individuals based primarily on nitrogen balance methodology. The aim of this study was to determine the estimated average protein requirement and recommended protein intake in endurance athletes during an acute 3-d controlled training period using the indicator amino acid oxidation method. After 2-d of controlled diet (1.4 g protein/kg/d and training (10 and 5km/d, respectively, six male endurance-trained adults (28±4 y of age; Body weight, 64.5±10.0 kg; VO2peak, 60.3±6.7 ml·kg-1·min-1; means±SD performed an acute bout of endurance exercise (20 km treadmill run prior to consuming test diets providing variable amounts of protein (0.2-2.8 g·kg-1·d-1 and sufficient energy. Protein was provided as a crystalline amino acid mixture based on the composition of egg protein with [1-13C]phenylalanine provided to determine whole body phenylalanine flux, 13CO2 excretion, and phenylalanine oxidation. The estimated average protein requirement was determined as the breakpoint after biphasic linear regression analysis with a recommended protein intake defined as the upper 95% confidence interval. Phenylalanine flux (68.8±8.5 μmol·kg-1·h-1 was not affected by protein intake. 13CO2 excretion displayed a robust bi-phase linear relationship (R2 = 0.86 that resulted in an estimated average requirement and a recommended protein intake of 1.65 and 1.83 g protein·kg-1·d-1, respectively, which was similar to values based on phenylalanine oxidation (1.53 and 1.70 g·kg-1·d-1, respectively. We report a recommended protein intake that is greater than the RDA (0.8 g·kg-1·d-1 and current recommendations for endurance athletes (1.2-1.4 g·kg-1·d-1. Our results suggest that the metabolic demand for protein in endurance-trained adults on a higher volume training day is greater than their sedentary peers and current recommendations for athletes based

  8. Quantification of the amount of galacturonic acid residues in blocksequences in pectin homogalacturonan by enzymatic fingerprinting with exo- and endo-polygalacturonase II from Aspergillus niger

    DEFF Research Database (Denmark)

    Limberg, G; Körner, R; Buchholt, H C

    2000-01-01

    A method to determine the amount of galacturonic acid in blocksequence (BS) in pectin homogalacturonan (HG) is described. The method is based on a combination of endopolygalacturonase II (endo-PG II) and exopolygalacturonase (exo-PG) digestion followed by quantification of the liberated galacturo...

  9. Efficient biorefinery of waste activated sludge and vinegar residue into volatile fatty acids: Effect of feedstock conditioning on performance and microbiology

    DEFF Research Database (Denmark)

    Varrone, Cristiano

    2018-01-01

    acid (SA) pretreated VR, respectively. Based on composition analysis, this improvement was mainly due to C2–C3 VFAs production. The hydrolysis rate constants in co-digestion tests, e.g., kh_TA = 0.0045 h−1, were also higher than that observed during mono-digestion (0.0018 h−1). Addition of VR greatly...

  10. Efficient autophosphorylation and phosphorylation of the beta-subunit by casein kinase-2 require the integrity of an acidic cluster 50 residues downstream from the phosphoacceptor site

    DEFF Research Database (Denmark)

    Boldyreff, B; Meggio, F; Pinna, L A

    1994-01-01

    Various beta-mutants were investigated either as subunits or as substrates for casein kinase 2 (CK-2), in the absence of presence of polylysine. A total of 21 beta-mutants were characterized for their susceptibility to autophosphorylation, by combining them in equimolar amounts with the recombina...

  11. Mannobiose Binding Induces Changes in Hydrogen Bonding and Protonation States of Acidic Residues in Concanavalin A As Revealed by Neutron Crystallography

    Energy Technology Data Exchange (ETDEWEB)

    Gerlits, Oksana O. [UT/ORNL; Coates, Leighton [Biology; Woods, Robert J. [Complex; Kovalevsky, Andrey [Biology

    2017-08-30

    Plant lectins are carbohydrate-binding proteins with various biomedical applications. Concanavalin A (Con A) holds promise in treating cancerous tumors. To better understand the Con A carbohydrate binding specificity, we obtained a room-temperature neutron structure of this legume lectin in complex with a disaccharide Manα1–2Man, mannobiose. The neutron structure afforded direct visualization of the hydrogen bonding between the protein and ligand, showing that the ligand is able to alter both protonation states and interactions for residues located close to and distant from the binding site. An unprecedented low-barrier hydrogen bond was observed forming between the carboxylic side chains of Asp28 and Glu8, with the D atom positioned equidistant from the oxygen atoms having an O···D···O angle of 101.5°.

  12. Internalisation of the mu-opioid receptor by endomorphin-1 and leu-enkephalin is dependant on aromatic amino acid residues.

    Science.gov (United States)

    Del Borgo, Mark P; Blanchfield, Joanne T; Toth, Istvan

    2008-04-15

    The opioid receptor system in the central nervous system controls a number of physiological processes, most notably pain. However, most opioids currently available have a variety of side-effects as well as exhibiting tolerance. Tolerance is most likely to be a complex phenomenon, however, the role of receptor internalisation is thought to play a crucial role. In this study, we examined the role of aromaticity in ligand-mediated receptor internalisation of the mu-opioid receptor (MOPR). These studies show that the amount of receptor internalisation may be dependant on the amphiphilicity of the ligand. Specifically, deletion of the C-terminus aromatic residues of endomorphin 1, particularly tryptophan reduces receptor-mediated internalisation whilst the addition of tryptophan within the enkephalin sequence increases receptor internalisation and decreases tolerance.

  13. H9N2 influenza virus acquires intravenous pathogenicity on the introduction of a pair of di-basic amino acid residues at the cleavage site of the hemagglutinin and consecutive passages in chickens

    Directory of Open Access Journals (Sweden)

    Sakoda Yoshihiro

    2011-02-01

    Full Text Available Abstract Background Outbreaks of avian influenza (AI caused by infection with low pathogenic H9N2 viruses have occurred in poultry, resulting in serious economic losses in Asia and the Middle East. It has been difficult to eradicate the H9N2 virus because of its low pathogenicity, frequently causing in apparent infection. It is important for the control of AI to assess whether the H9N2 virus acquires pathogenicity as H5 and H7 viruses. In the present study, we investigated whether a non-pathogenic H9N2 virus, A/chicken/Yokohama/aq-55/2001 (Y55 (H9N2, acquires pathogenicity in chickens when a pair of di-basic amino acid residues is introduced at the cleavage site of its HA molecule. Results rgY55sub (H9N2, which had four basic amino acid residues at the HA cleavage site, replicated in MDCK cells in the absence of trypsin after six consecutive passages in the air sacs of chicks, and acquired intravenous pathogenicity to chicken after four additional passages. More than 75% of chickens inoculated intravenously with the passaged virus, rgY55sub-P10 (H9N2, died, indicating that it is pathogenic comparable to that of highly pathogenic avian influenza viruses (HPAIVs defined by World Organization for Animal Health (OIE. The chickens inoculated with the virus via the intranasal route, however, survived without showing any clinical signs. On the other hand, an avirulent H5N1 strain, A/duck/Hokkaido/Vac-1/2004 (Vac1 (H5N1, acquired intranasal pathogenicity after a pair of di-basic amino acid residues was introduced into the cleavage site of the HA, followed by two passages by air sac inoculation in chicks. Conclusion The present results demonstrate that an H9N2 virus has the potential to acquire intravenous pathogenicity in chickens although the morbidity via the nasal route of infection is lower than that of H5N1 HPAIV.

  14. Prediction of binding modes between protein L-isoaspartyl (D-aspartyl) O-methyltransferase and peptide substrates including isomerized aspartic acid residues using in silico analytic methods for the substrate screening.

    Science.gov (United States)

    Oda, Akifumi; Noji, Ikuhiko; Fukuyoshi, Shuichi; Takahashi, Ohgi

    2015-12-10

    Because the aspartic acid (Asp) residues in proteins are occasionally isomerized in the human body, not only l-α-Asp but also l-β-Asp, D-α-Asp and D-β-Asp are found in human proteins. In these isomerized aspartic acids, the proportion of D-β-Asp is the largest and the proportions of l-β-Asp and D-α-Asp found in human proteins are comparatively small. To explain the proportions of aspartic acid isomers, the possibility of an enzyme able to repair l-β-Asp and D-α-Asp is frequently considered. The protein L-isoaspartyl (D-aspartyl) O-methyltransferase (PIMT) is considered one of the possible repair enzymes for l-β-Asp and D-α-Asp. Human PIMT is an enzyme that recognizes both l-β-Asp and D-α-Asp, and catalyzes the methylation of their side chains. In this study, the binding modes between PIMT and peptide substrates containing l-β-Asp or D-α-Asp residues were investigated using computational protein-ligand docking and molecular dynamics simulations. The results indicate that carboxyl groups of both l-β-Asp and D-α-Asp were recognized in similar modes by PIMT and that the C-terminal regions of substrate peptides were located in similar positions on PIMT for both the l-β-Asp and D-α-Asp peptides. In contrast, for peptides containing l-α-Asp or D-β-Asp residues, which are not substrates of PIMT, the computationally constructed binding modes between PIMT and peptides greatly differed from those between PIMT and substrates. In the nonsubstrate peptides, not inter- but intra-molecular hydrogen bonds were observed, and the conformations of peptides were more rigid than those of substrates. Thus, the in silico analytical methods were able to distinguish substrates from nonsubstrates and the computational methods are expected to complement experimental analytical methods. Copyright © 2015 Elsevier B.V. All rights reserved.

  15. Electroremediation of air pollution control residues in a continuous reactor

    DEFF Research Database (Denmark)

    Jensen, Pernille Erland; Ferreira, Célia M. D.; Hansen, Henrik K.

    2010-01-01

    Air pollution control (APC) residue from municipal solid waste incineration is considered hazardous waste due to its alkalinity and high content of salts and mobile heavy metals. Various solutions for the handling of APC-residue exist, however most commercial solutions involve landfilling. A demand...... were made with raw residue, water-washed residue, acid washed residue and acid-treated residue with emphasis on reduction of heavy metal mobility. Main results indicate that the reactor successfully removes toxic elements lead, copper, cadmium and zinc from the feed stream, suggesting...

  16. Expression and mutagenesis of the sea anemone toxin Av2 reveals key amino acid residues important for activity on voltage-gated sodium channels.

    Science.gov (United States)

    Moran, Yehu; Cohen, Lior; Kahn, Roy; Karbat, Izhar; Gordon, Dalia; Gurevitz, Michael

    2006-07-25

    Type I sea anemone toxins are highly potent modulators of voltage-gated Na-channels (Na(v)s) and compete with the structurally dissimilar scorpion alpha-toxins on binding to receptor site-3. Although these features provide two structurally different probes for studying receptor site-3 and channel fast inactivation, the bioactive surface of sea anemone toxins has not been fully resolved. We established an efficient expression system for Av2 (known as ATX II), a highly insecticidal sea anemone toxin from Anemonia viridis (previously named A. sulcata), and mutagenized it throughout. Each toxin mutant was analyzed in toxicity and binding assays as well as by circular dichroism spectroscopy to discern the effects derived from structural perturbation from those related to bioactivity. Six residues were found to constitute the anti-insect bioactive surface of Av2 (Val-2, Leu-5, Asn-16, Leu-18, and Ile-41). Further analysis of nine Av2 mutants on the human heart channel Na(v)1.5 expressed in Xenopus oocytes indicated that the bioactive surfaces toward insects and mammals practically coincide but differ from the bioactive surface of a structurally similar sea anemone toxin, Anthopleurin B, from Anthopleura xanthogrammica. Hence, our results not only demonstrate clear differences in the bioactive surfaces of Av2 and scorpion alpha-toxins but also indicate that despite the general conservation in structure and importance of the Arg-14 loop and its flanking residues Gly-10 and Gly-20 for function, the surface of interaction between different sea anemone toxins and Na(v)s varies.

  17. A highly bioavailable omega-3 free fatty acid formulation improves the cardiovascular risk profile in high-risk, statin-treated patients with residual hypertriglyceridemia (the ESPRIT trial).

    Science.gov (United States)

    Maki, Kevin C; Orloff, David G; Nicholls, Stephen J; Dunbar, Richard L; Roth, Eli M; Curcio, Danielle; Johnson, Judith; Kling, Douglas; Davidson, Michael H

    2013-09-01

    A novel omega-3 formulation in free fatty acid form (OM3-FFA) has as much as 4-fold greater bioavailability than ethyl ester forms and reduces triglyceride (TG) levels in patients with severe hypertriglyceridemia. This study was designed to evaluate the efficacy of adding OM3-FFA (2 or 4 g/d) to statin therapy for lowering non-HDL-C and TG levels in subjects with persistent hypertriglyceridemia and at high risk for cardiovascular disease. In this double-blind, parallel-group study, 647 diet-stable patients with fasting TG levels ≥ 200 mg/dL and <500 mg/dL (treated with a maximally tolerated dose of statin or statin with ezetimibe) and at high risk for cardiovascular disease were randomized to 6 weeks of treatment with capsules of control (olive oil [OO]) 4 g/d, OM3-FFA 2 g/d (plus 2 g/d OO), or OM3-FFA 4 g/d. Assessments included fasting serum levels of lipids and apolipoproteins (apo); plasma concentrations of eicosapentaenoic acid, docosahexaenoic acid, docosapentaenoic acid, and arachidonic acid; and laboratory safety values and adverse events. In the 627 subjects in the intention to treat sample, non-HDL-C levels were reduced with OM3-FFA 2 g/d and OM3-FFA 4 g/d (-3.9% and -6.9%, respectively) compared with OO (-0.9%) (both, P < 0.05), as were TG levels (-14.6% and -20.6%, respectively, vs -5.9%; both, P < 0.001). LDL-C levels increased with OM3-FFA 2 g/d (4.6%) compared with OO (1.1%) (P = 0.025) but not with OM3-FFA 4 g/d (1.3%). Total cholesterol and VLDL-C concentrations were reduced compared with OO with both OM3-FFA dosages, and the total cholesterol/HDL-C ratio and apo AI and apo B levels were significantly lowered with OM3-FFA 4 g/d only (all at least P < 0.05). Percent changes from baseline in HDL-C did not differ between OO and either OM3-FFA group. Plasma concentrations of docosahexaenoic acid, eicosapentaenoic acid, and docosapentaenoic acid were significantly increased and arachidonic acid was significantly reduced in both OM3-FFA treatment

  18. Risk-based Strategy to Determine Testing Requirement for the Removal of Residual Process Reagents as Process-related Impurities in Bioprocesses.

    Science.gov (United States)

    Qiu, Jinshu; Li, Kim; Miller, Karen; Raghani, Anil

    2015-01-01

    The purpose of this article is to recommend a risk-based strategy for determining clearance testing requirements of the process reagents used in manufacturing biopharmaceutical products. The strategy takes account of four risk factors. Firstly, the process reagents are classified into two categories according to their safety profile and history of use: generally recognized as safe (GRAS) and potential safety concern (PSC) reagents. The clearance testing of GRAS reagents can be eliminated because of their safe use historically and process capability to remove these reagents. An estimated safety margin (Se) value, a ratio of the exposure limit to the estimated maximum reagent amount, is then used to evaluate the necessity for testing the PSC reagents at an early development stage. The Se value is calculated from two risk factors, the starting PSC reagent amount per maximum product dose (Me), and the exposure limit (Le). A worst-case scenario is assumed to estimate the Me value, that is common. The PSC reagent of interest is co-purified with the product and no clearance occurs throughout the entire purification process. No clearance testing is required for this PSC reagent if its Se value is ≥1; otherwise clearance testing is needed. Finally, the point of the process reagent introduction to the process is also considered in determining the necessity of the clearance testing for process reagents. How to use the measured safety margin as a criterion for determining PSC reagent testing at process characterization, process validation, and commercial production stages are also described. A large number of process reagents are used in the biopharmaceutical manufacturing to control the process performance. Clearance testing for all of the process reagents will be an enormous analytical task. In this article, a risk-based strategy is described to eliminate unnecessary clearance testing for majority of the process reagents using four risk factors. The risk factors included

  19. Comparative estimation of inevitable endogenous ileal flow of amino acids in Pekin ducks under varying dietary or physiological conditions and their significance to nutritional requirements for amino acids.

    Science.gov (United States)

    Akinde, D O

    2017-10-01

    In 2 experiments in Pekin ducks the inevitable endogenous ileal flow (IEIF) of AA was estimated at changing intake and source of crude fiber (CF) or soybean oil (SO) level. Also the roles of dry matter intake (DMI) and BW or age as well as the proportion of IEIF in the dietary requirement for AA were studied. In experiment 1 three basal CP (20, 60, or 100 g/kg) diets were formulated containing a low CF (LCF, 30 g/kg) or high (HCF, 80 g/kg) level; achieved with cellulose supplementation. All diets were similar in every other respect including having SO content of 40 g/kg. Four floor pens of eight 85-day-old ducks were randomly allocated to each diet. Similar diets were mixed in experiment 2 but corn cob meal replaced cellulose as the fiber source. A high SO (HSO) series was also formed by increasing the SO level from 40 g/kg in the basal series to 100 g/kg. Thus the LCF series was concurrently classified as low SO (LSO) series to control SO effect. Each of the eventual 9 diets were fed to 5 floor pens of ten 65-day-old ducks. Ileal AA flow was measured after a 5 day feeding period in both experiments. Linear regression was calculated between ileal flow and dietary intake of individual AA. The IEIF interpreted as the y-intercept of each linear function responded neither to elevated ingestion of each CF type nor to SO level. Age and DMI had no effect on IEIF computed in relation to BW, but wide discrepancies resulted when related to DMI. Overall IEIF of AA varied between 14.3 to 129.8 mg/kg BW d-1. These flows were established in model computations to account for 10 to 64% of the recommended intake of limiting AA. In conclusion the ileal inevitable flow is constant within the dietary/age conditions investigated. However it is modulated by feed intake and accounts for a significant portion of total amino acid requirement. © 2017 Poultry Science Association Inc.

  20. An accurate density functional theory based estimation of pK(a) values of polar residues combined with experimental data: from amino acids to minimal proteins.

    Science.gov (United States)

    Matsui, Toru; Baba, Takeshi; Kamiya, Katsumasa; Shigeta, Yasuteru

    2012-03-28

    We report a scheme for estimating the acid dissociation constant (pK(a)) based on quantum-chemical calculations combined with a polarizable continuum model, where a parameter is determined for small reference molecules. We calculated the pK(a) values of variously sized molecules ranging from an amino acid to a protein consisting of 300 atoms. This scheme enabled us to derive a semiquantitative pK(a) value of specific chemical groups and discuss the influence of the surroundings on the pK(a) values. As applications, we have derived the pK(a) value of the side chain of an amino acid and almost reproduced the experimental value. By using our computing schemes, we showed the influence of hydrogen bonds on the pK(a) values in the case of tripeptides, which decreases the pK(a) value by 3.0 units for serine in comparison with those of the corresponding monopeptides. Finally, with some assumptions, we derived the pK(a) values of tyrosines and serines in chignolin and a tryptophan cage. We obtained quite different pK(a) values of adjacent serines in the tryptophan cage; the pK(a) value of the OH group of Ser13 exposed to bulk water is 14.69, whereas that of Ser14 not exposed to bulk water is 20.80 because of the internal hydrogen bonds.

  1. [Intra-Articular Application of Tranexamic Acid Significantly Reduces Blood Loss and Transfusion Requirement in Primary Total Knee Arthroplasty].

    Science.gov (United States)

    Lošťák, J; Gallo, J; Špička, J; Langová, K

    2016-01-01

    PURPOSE OF THE STUDY The aim of this prospective study was to investigate the effect of topical application of tranexamic acid (TXA, Exacyl) on the amount of post-operative blood loss, and blood transfusion requirement in patients undergoing primary total knee arthroplasty (TKA). Attention was paid to early complications potentially associated with TXA administration, such as haematoma, wound exudate, or knee swelling. In addition, the economic benefit of TXA treatment was also taken into account. MATERIAL AND METHODS The study included 238 patients (85 men and 153 women) who underwent primary total knee arthroplasty (TKA) at our department between January 2013 and November 2015. A group of 119 patients (41 men and 78 women) received intraarticular TXA injections according to the treatment protocol (TXA group). A control group matched in basic characteristics to the TXA group also consisted of 119 patients. The average age in the TXA group was 69.8 years, and the most frequent indication for TKA surgery was primary knee osteoarthritis (81.5%). In each patient, post-operative volume of blood lost from drains and total blood loss including hidden blood loss were recorded, as well as post-operative haemoglobin and haematocrit levels. On discharge of each patient from hospital, the size and site of a haematoma; wound exudate, if present after post-operative day 4; joint swelling; range of motion and early revision surgery, if performed, were evaluated. Requirements of analgesic drugs after surgery were also recorded. RESULTS In the TXA group, blood losses from drains were significantly lower than in the control group (456.7 ± 270.8 vs 640.5 ±448.2; p = 0.004). The median value for blood losses from drains was lower by 22% and the average value for total blood loss, including hidden losses, was also lower than in the control group (762.4 ± 345.2 ml vs 995.5 ± 457.3 ml). The difference in the total amount of blood loss between the two groups was significant (p = 0

  2. Requirement of Digestible Sulfur Amino Acids in Laying Hens Fed Sorghum- and Soybean Meal-Based Diets

    Directory of Open Access Journals (Sweden)

    RS Gomez

    Full Text Available ABSTRACT Two experiments were done to evaluate the effect of increasing levels of dietary digestible methionine (Met and Met:cysteine (Met:Cys ratio on the productivity of Hy-Line W-36 laying hens fed sorghum- and soybean meal-based diets. In Exp. 1, 160 hens from 68 to 75 weeks of age were assigned to four dietary levels of digestible Met (0.20 0.24, 0.28 and 0.32%. The digestible total sulfur amino acids:Lysine (TSAA:Lys ratios were: 62, 68, 76 and 84%. In Exp. 2, 192 hens from 76-83 weeks of age were assigned to four dietary digestible Met:Cys ratios (160, 116.7, 85.7 and 62.5%. The digestible TSAA:Lys ratio was kept constant across diets (80%. Results were subjected to ANOVA and linear regression analyses. In Exp. 1, optimal egg production, egg mass, and feed efficiency responses were observed at 0.30 and 0.50% of dietary digestible Met and TSAA, respectively (quadratic effect, p<0.05. Live performance was maximized with digestible Met and TSAA in takes of 288 and 478 mg/hen/d, respectively. In Exp. 2, optimal egg production and feed efficiency responses were observed at 151 and 150% of dietary digestible Met:Cys ratios, respectively (quadratic effect, p<0.05. The digestible Met, Cys and TSAA intake to maximize egg production and feed efficiency were 313, 207 and 510 mg/hen/d, respectively. The requirements for sulfur AA in Hy-Line W-36 hens from 68 to 83 weeks of age fed sorghum- and soybean meal-based diets fell inside the range of the requirements previously estimated in hens fed corn-soybean meal based diets.

  3. Identification of NAD interacting residues in proteins

    Directory of Open Access Journals (Sweden)

    Raghava Gajendra PS

    2010-03-01

    Full Text Available Abstract Background Small molecular cofactors or ligands play a crucial role in the proper functioning of cells. Accurate annotation of their target proteins and binding sites is required for the complete understanding of reaction mechanisms. Nicotinamide adenine dinucleotide (NAD+ or NAD is one of the most commonly used organic cofactors in living cells, which plays a critical role in cellular metabolism, storage and regulatory processes. In the past, several NAD binding proteins (NADBP have been reported in the literature, which are responsible for a wide-range of activities in the cell. Attempts have been made to derive a rule for the binding of NAD+ to its target proteins. However, so far an efficient model could not be derived due to the time consuming process of structure determination, and limitations of similarity based approaches. Thus a sequence and non-similarity based method is needed to characterize the NAD binding sites to help in the annotation. In this study attempts have been made to predict NAD binding proteins and their interacting residues (NIRs from amino acid sequence using bioinformatics tools. Results We extracted 1556 proteins chains from 555 NAD binding proteins whose structure is available in Protein Data Bank. Then we removed all redundant protein chains and finally obtained 195 non-redundant NAD binding protein chains, where no two chains have more than 40% sequence identity. In this study all models were developed and evaluated using five-fold cross validation technique on the above dataset of 195 NAD binding proteins. While certain type of residues are preferred (e.g. Gly, Tyr, Thr, His in NAD interaction, residues like Ala, Glu, Leu, Lys are not preferred. A support vector machine (SVM based method has been developed using various window lengths of amino acid sequence for predicting NAD interacting residues and obtained maximum Matthew's correlation coefficient (MCC 0.47 with accuracy 74.13% at window length 17

  4. P-glycoprotein binds to ezrin at amino acid residues 149-242 in the FERM domain and plays a key role in the multidrug resistance of human osteosarcoma.

    Science.gov (United States)

    Brambilla, Daria; Zamboni, Silvia; Federici, Cristina; Lugini, Luana; Lozupone, Francesco; De Milito, Angelo; Cecchetti, Serena; Cianfriglia, Maurizio; Fais, Stefano

    2012-06-15

    Overexpression of the mdr1 gene encoding P-glycoprotein (Pgp) exerts a major role in reducing the effectiveness of cytotoxic therapy in osteosarcoma. The interaction between actin and Pgp has been shown to be instrumental in the establishment of multidrug resistance (MDR) in human tumor cells. The cytoskeleton linker ezrin exerts a pivotal role in maintaining the functional connection between actin and Pgp. We investigated the role of ezrin in a human multidrug-resistant osteosarcoma cell line overexpressing Pgp and compared it to its counterpart that overexpresses an ezrin deletion mutant. The results showed that Pgp binds at amino acid residues 149-242 of the N-terminal domain of ezrin. The interaction between ezrin and Pgp occurs in the plasma membrane of MDR cells, where they also co-localize with the ganglioside G(M1) located in lipid rafts. The overexpression of the ezrin deletion mutant entirely restored drug susceptibility of osteosarcoma cells, consistent with Pgp dislocation to cytoplasmic compartments and abrogation of G(M1) /Pgp co-localization at the plasma membrane. Our study provides evidence that ezrin exerts a key role in MDR of human osteosarcoma cells through a Pgp-ezrin-actin connection that is instrumental for the permanence of Pgp into plasma membrane lipid rafts. We also show for the first time that Pgp-binding site is localized to amino acid residues 149-242 of the ezrin Band 4.1, Ezrin/Radixin/Moesin (FERM) domain, thus proposing a specific target for future molecular therapy aimed at counteracting MDR in osteosarcoma patients. Copyright © 2011 UICC.

  5. Evolutionary conservativeness of electric field in the Cu,Zn superoxide dismutase active site. Evidence for co-ordinated mutation of charged amino acid residues.

    Science.gov (United States)

    Desideri, A; Falconi, M; Polticelli, F; Bolognesi, M; Djinovic, K; Rotilio, G

    1992-01-05

    Equipotential lines were calculated, using the Poisson-Boltzmann equation, for six Cu,Zn superoxide dismutases with different protein electric charge and various degrees of sequence homology, namely those from ox, pig, sheep, yeast, and the isoenzymes A and B from the amphibian Xenopus laevis. The three-dimensional structures of the porcine and ovine superoxide dismutases were obtained by molecular modelling reconstruction using the structure of the highly homologous bovine enzyme as a template. The three-dimensional structure of the evolutionary distant yeast Cu,Zn superoxide dismutase was recently resolved by us, while computer-modelled structures are available for X. laevis isoenzymes. The six proteins display large differences in the net protein charge and distribution of electrically charged surface residues but the trend of the equipotential lines in the proximity of the active sites was found to be constant in all cases. These results are in line with the very similar catlytic rate constants experimentally measured for the corresponding enzyme activities. This analysis shows that electrostatic guidance for the enzyme-substrate interaction in Cu,Zn superoxide dismutases is related to a spatial distribution of charges, arranged so as to maintain, in the area surrounding the active sites, an identical electrostatic potential distribution, which is conserved in the evolution of this protein family.

  6. The dapE-encoded N-succinyl-L,L-Diaminopimelic Acid Desuccinylase from Haemophilus influenzae Contains two Active Site Histidine Residues

    OpenAIRE

    Gillner, Danuta M.; Bienvenue, David L.; Nocek, Boguslaw P.; Joachimiak, Andrzej; Zachary, Vincentos; Bennett, Brian; Holz, Richard C.

    2008-01-01

    The catalytic and structural properties of the H67A and H349A altered dapE-encoded N-succinyl-l,l-diaminopimelic acid desuccinylase (DapE) from H. influenzae were investigated. Based on sequence alignment with CPG2 both H67 and H349 were predicted to be Zn(II) ligands. Catalytic activity was observed for the H67A altered DapE enzyme which exhibited kcat = 1.5 ± 0.5 sec−1 and Km = 1.4 ± 0.3 mM. No catalytic activity was observed for H349A under the experimental conditions used. The EPR and ele...

  7. Conformation-Specific IR and UV Spectroscopy of the Amino Acid Glutamine: Amide-Stacking and Hydrogen Bonding in AN Important Residue in Neurodegenerative Diseases

    Science.gov (United States)

    Walsh, Patrick S.; Dean, Jacob C.; Zwier, Timothy S.

    2014-06-01

    Glutamine plays an important role in several neurodegenerative diseases including Huntington's disease (HD) and Alzheimer's disease (AD). An intriguing aspect of the structure of glutamine is its incorporation of an amide group in its side chain, thereby opening up the possibility of forming amide-amide H-bonds between the peptide backbone and side chain. In this study the conformational preferences of two capped gluatamines Z(carboxybenzyl)-Glutamine-X (X=OH, NHMe) are studied under jet-cooled conditions in the gas phase in order to unlock the intrinsic structural motifs that are favored by this flexible sidechain. Conformational assignments are made by comparing the hydride stretch ( 3100-3700 cm-1) and amide I and II ( 1400-1800 cm-1) resonant ion-dip infrared spectra with predictions from harmonic frequency calculations. Assigned structures will be compared to previously published results on both natural and unnatural residues. Particular emphasis will be placed on the comparison between glutamine and unconstrained γ-peptides due to the similar three-carbon spacing between backbone and side chain in glutamine to the backbone spacing in γ-peptides. The ability of the glutamine side-chain to form amide stacked conformations will be a main focus, along with the prevalence of extended backbone type structures. W. H. James, III, C W. Müller, E. G. Buchanan, M. G. D. Nix, L. Guo, L. Roskop, M. S. Gordon, L. V. Slipchenko, S. H. Gellman, and T. S. Zwier, J. Am. Chem. Soc., 2009, 131(40), 14243-14245.

  8. Networks of High Mutual Information Define the Structural Proximity of Catalytic Sites: Implications for Catalytic Residue Identification

    DEFF Research Database (Denmark)

    Buslje, Cristina Marino; Teppa, Elin; Di Doménico, Tomas

    2010-01-01

    other non-functional conserved residues. Using a data set of 434 Pfam families included in the catalytic site atlas (CSA) database, we tested this hypothesis and demonstrated that MI can complement amino acid conservation scores to detect CR. The Kullback-Leibler (KL) conservation measurement was shown.......90, the Cls method was found to have a sensitivity of 0.816. In summary, we demonstrate that networks of residues with high MI provide a distinct signature on CR and propose that such a signature should be present in other classes of functional residues where the requirement to maintain a particular function...

  9. Distribution and origin of major and trace elements (particularly REE, U and Th) into labile and residual phases in an acid soil profile (Vosges Mountains, France)

    Science.gov (United States)

    Aubert, D.; Probst, A.; Stille, P.

    2003-04-01

    Physical and chemical weathering of rocks and minerals lead to soil formation and allow the removal of chemical elements from these systems to ground- or surface waters. But most of the time the determination of element concentrations in soils is not sufficient to estimate whether they are being accumulated or what is their ability to be released in the environment. Thus, the distribution and chemical binding for a given element is very important because it determines its mobility and potential bioavailability throughout a soil profile. Heavy metals and REE (Rare Earth Elements) are particularly of environmental concern because of their potential toxicity. For most of them, their chemical form strongly depends on the evolution of physico-chemical parameters like pH or redox conditions that will induce adsorption-desorption, complexation or co-precipitation phenomena in the material. The purpose of this study is to determine the distribution of several major and trace elements (especially REE, Th and U) in an acidic forested podzolic soil profile from the Vosges Mountains (France). To achieve this goal we use a 7 step sequential extraction procedure that allows determining precisely the origin and the behaviour of particular elements in the environment (Leleyter et al., 1999). In addition we performed leaching experiments using very dilute acetic and hydrochloric acid in order to establish the origin of REE in this soil. The results of the sequential extraction indicate that most of the metals, Th and U are mainly bound to Fe oxides. Organic matter appears also to be a great carrier of P, Ca, Fe and REE even if its content is very low in the deep horizons of the soil. Moreover, we show that in each soil horizon, middle REE (MREE) to heavy REE (HREE) are more labile than light REE (LREE). Leaching experiments using dilute acid solution further suggest that in the shallowest horizons REE largely derive from atmospheric deposition whereas at greater depth, weathering

  10. Resíduos vegetais na superfície do solo afetam a acidez do solo e a eficiência do herbicida flumetsulam Soil surface residues affect soil acidity and flumetsulam herbicid efficiency

    Directory of Open Access Journals (Sweden)

    Antonio Sergio do Amaral

    2000-10-01

    Full Text Available Com o objetivo de avaliar o potencial de resíduos de duas espécies vegetais em alterar a acidez do solo e a atividade do herbicida flumetsulam, foi conduzido um experimento em casa de vegetação no Departamento de Solos da Universidade Federal do Rio Grande do Sul, em novembro de 1998. Amostras da camada superficial (0-20cm de um cambissolo húmico distrófico foram colocadas em vasos, com capacidade de 1,0kg, onde se aplicou na superfície: 0, 5 e 10t ha-1 de resíduos de aveia-preta e de ervilhaca comum, com e sem aplicação do herbicida. Utilizou-se aveia-branca como cultura reagente. O delineamento experimental foi o inteiramente casualizado com três repetições. O resíduo da ervilhaca aumentou o pH do solo e ambos os resíduos diminuíram o alumínio trocável na camada de 0-3cm de profundidade, sendo o efeito da ervilhaca mais pronunciado. O decréscimo do alumínio trocável foi relacionado a dois mecanismos: complexação pela matéria orgânica e aumento do pH. Os resíduos vegetais aplicados sobre a superfície do solo aumentaram a eficiência do herbicida flumetsulam, especialmente quando o herbicida foi aplicado sobre os resíduos da leguminosa, que teve maior efeito na elevação do pH do solo.An experiment was conducted in the greenhouse of the Soils Department of the Federal University of Rio Grande do Sul, in November of 1998, to evaluate the potential of two crop residues to modify the acidity of the soil and the activity of the flumetsulam herbicide. The experimental units consisted of pots containing an Haplumbrept soil from the surface layer (0-20cm in with it was applyed 0, 5 and 10t ha-1 of black oat and of common vicia residues, with and without the herbicide application in the soil surface, and arranged in a complete randomized design, with three replications. White oat was used as test culture. Vicia residues increase soil pH and both residues decreased exchangeable Al in the 0-3cm layer, with the effect of vicia

  11. Influence of several nonferrous metals in the treatment of residual liquors from hydrochloric acid pickling processes. Influencia de diversos metales no ferreos en el tratamiento de lejias residuales de decapado con acido clorhidrico

    Energy Technology Data Exchange (ETDEWEB)

    Negro, C.; Cobos, M.A.; Latorre, R.; Dufour, J.; Formoso, A.; Lopez, F.

    1994-01-01

    In the oxiprecipitation of waste liquors from siderurgical processes of pickling with hydrochloric acid, several kinds of iron oxides and oxihydroxides are obtained: alpha-FeOOH, gamma-FeOOH, Fe[sub 3]O[sub 4], gamma-Fe[sub 2]O[sub 3]. Fe[sub 2]O[sub 3].1,2H[sub 2]O, etc. These products can be used like pigments in the painting industry and like raw materials for the obtaining of ferrites. Varying the operation conditions, the presence of these products can be changed greatly, obtaining different mixtures of them. The presence of non-ferrous metals catalyzes and modifies the mechanism of the reaction, yielding pure products. This simplifies their later industrial applications. The aim of this work is to determine the influence of Cu(II), Zn(II), Mo(VI) and Al(III) on the oxiprecipitation of residual liquors from hydrochloric acid pickling processes, selecting the most favourable operation conditions at which it is possible to obtain products for industrial applications.

  12. Mobilidade de íons em solo ácido com aplicação de calcário, ácido orgânico e material vegetal em superfície Ion mobility in acid soils with surface application of lime, organic acid and crop residues

    Directory of Open Access Journals (Sweden)

    Milton Ferreira Moraes

    2007-08-01

    Full Text Available Há controvérsias quanto à eficiência da correção da acidez da camada subsuperficial pela aplicação de calcário na presença de materiais vegetais de plantas de cobertura e faltam informações sobre os mecanismos envolvidos no processo. O objetivo deste estudo foi quantificar a contribuição dos materiais vegetais de plantas de cobertura, com ênfase nos seus conteúdos de ácidos orgânicos de baixa massa molar e nutrientes solúveis, sobre a mobilização, no perfil do solo, dos produtos da dissolução do calcário aplicado em superfície. Foram desenvolvidos dois experimentos em laboratório, usando colunas de PVC de 30 cm de altura com amostras deformadas de um Latossolo Vermelho textura muito argilosa. Os tratamentos constituíram-se da aplicação isolada ou conjunta de calcário para atingir 80 % de saturação por bases (6,1 t ha-1 e de materiais vegetais (20 t ha-1 de nabo forrageiro e aveia-preta, bem como de soluções de ácidos orgânicos e sais neutros aproximadamente equivalentes ao conteúdo dessas espécies. A calagem isolada ou em associação com os materiais vegetais promoveu a redução da acidez somente na camada superficial (0-8 cm. A baixa taxa de recuperação dos ácidos orgânicos adicionados (The efficiency of subsurface acidity alleviation by surface liming in the presence of crop residues is controversial and more information is needed. The objective of this study was to quantify the contribution of cover crop residues, regarding their contents of low molar mass organic acids and soluble nutrients to mobilization in the soil profile of the reaction products of surface-applied lime. Two experiments were carried out under laboratory conditions using 30 cm high PVC cylinders filled with acid and clayey Red Latosol. Treatments consisted of liming to 80 % soil base saturation (6.1 t ha-1 solely as or liming combined with radish (Raphanus sativus or with black oat (Avena strigosa crop residues (20 t ha-1, as

  13. Minimization of zirconium chlorinator residues

    International Nuclear Information System (INIS)

    Green, G.K.; Harbuck, D.D.

    1995-01-01

    Zirconium chlorinator residues contain an array of rare earths, scandium, unreacted coke, and radioactive thorium and radium. Because of the radioactivity, the residues must be disposed in special waste containment facilities. As these sites become more congested, and with stricter environmental regulations, disposal of large volumes of wastes may become more difficult. To reduce the mass of disposed material, the US Bureau of Mines (USBM) developed technology to recover rare earths, thorium and radium, and unreacted coke from these residues. This technology employs an HCl leach to solubilize over 99% of the scandium and thorium, and over 90% of the rare earths. The leach liquor is processed through several solvent extraction stages to selectively recover scandium, thorium, and rare earths. The leach residue is further leached with an organic acid to solubilize radium, thus allowing unreacted coke to be recycled to the chlorinator. The thorium and radium waste products, which comprise only 2.1% of the original residue mass, can then be sent to the radioactive waste facility

  14. Nitrogen recycling from fuel-extracted algal biomass: residuals as the sole nitrogen source for culturing Scenedesmus acutus.

    Science.gov (United States)

    Gu, Huiya; Nagle, Nick; Pienkos, Philip T; Posewitz, Matthew C

    2015-05-01

    In this study, the reuse of nitrogen from fuel-extracted algal residues was investigated. The alga Scenedesmus acutus was found to be able to assimilate nitrogen contained in amino acids, yeast extracts, and proteinaceous alga residuals. Moreover, these alternative nitrogen resources could replace nitrate in culturing media. The ability of S. acutus to utilize the nitrogen remaining in processed algal biomass was unique among the promising biofuel strains tested. This alga was leveraged in a recycling approach where nitrogen is recovered from algal biomass residuals that remain after lipids are extracted and carbohydrates are fermented to ethanol. The protein-rich residuals not only provided an effective nitrogen resource, but also contributed to a carbon "heterotrophic boost" in subsequent culturing, improving overall biomass and lipid yields relative to the control medium with only nitrate. Prior treatment of the algal residues with Diaion HP20 resin was required to remove compounds inhibitory to algal growth. Copyright © 2014 Elsevier Ltd. All rights reserved.

  15. The Peroxisomal Enzyme L-PBE Is Required to Prevent the Dietary Toxicity of Medium-Chain Fatty Acids

    Directory of Open Access Journals (Sweden)

    Jun Ding

    2013-10-01

    Full Text Available Specific metabolic pathways are activated by different nutrients to adapt the organism to available resources. Although essential, these mechanisms are incompletely defined. Here, we report that medium-chain fatty acids contained in coconut oil, a major source of dietary fat, induce the liver ω-oxidation genes Cyp4a10 and Cyp4a14 to increase the production of dicarboxylic fatty acids. Furthermore, these activate all ω- and β-oxidation pathways through peroxisome proliferator activated receptor (PPAR α and PPARγ, an activation loop normally kept under control by dicarboxylic fatty acid degradation by the peroxisomal enzyme L-PBE. Indeed, L-pbe−/− mice fed coconut oil overaccumulate dicarboxylic fatty acids, which activate all fatty acid oxidation pathways and lead to liver inflammation, fibrosis, and death. Thus, the correct homeostasis of dicarboxylic fatty acids is a means to regulate the efficient utilization of ingested medium-chain fatty acids, and its deregulation exemplifies the intricate relationship between impaired metabolism and inflammation.

  16. Determination of glyphosate residuals and of their metabolite Aminomethyl-Phosphonic acid in waters, by means of liquid chromatography of high efficiency with post-column derivation and fluorescence detection

    International Nuclear Information System (INIS)

    Rodriguez, Hugo A; Guerrero, Jairo; Castro, Rene

    2002-01-01

    The glyphosate is a no selective herbicide largely used in the world in order to control annual and perennial weeds. Its principal metabolite in soils and waters is the Aminomethyl-Phosphonic Acid (AMPA) formed by micro organism's action. This herbicide is used in Colombia in high doses to illegal crops eradication of coca and Amapola and like natural accelerator in sugar cane, constituting an environmental and social problem for the country, being necessary the evaluation of glyphosate residues in different matrices. This study describes the validation of the analytical methodology for the simultaneous determination of glyphosate and its metabolite AMPA in waters of some Colombian regions. The experimental procedure pointed out two main steps: the first one was a cleaning, extraction and concentration step by solid phase extraction; the second step is the separation, identification and quantification of the compounds by High Performance Liquid Chromatography (HPLC) with post-column derivation and fluorescence detection. The results of the validation show that the methodology is specific, selective, precise and robust with linear calibration curve in the linear range between 10 and 750 μg/L, with limits of detection of 0.8 μg/L and limits of quantification of 2 μg/L for the two analyses. The recoveries are in the order of 73% for glyphosate and 70% for AMPA. More over analysis results are presented for water samples of some country regions where glyphosate is applied in different doses with different purposes, finding residues of the herbicide and its metabolite in concentrations above the allowed values in drinking waters for pesticides of toxicology category IV, like the glyphosate, according with the Colombian legislation

  17. The plant cuticle is required for osmotic stress regulation of abscisic acid biosynthesis and osmotic stress tolerance in Arabidopsis

    KAUST Repository

    Wang, Zhenyu; Xiong, Liming; Li, Wenbo; Zhu, Jian-Kang; Zhu, Jianhua

    2011-01-01

    Osmotic stress activates the biosynthesis of abscisic acid (ABA). One major step in ABA biosynthesis is the carotenoid cleavage catalyzed by a 9-cis epoxycarotenoid dioxygenase (NCED). To understand the mechanism for osmotic stress activation of ABA

  18. mTORC1 Activator SLC38A9 Is Required to Efflux Essential Amino Acids from Lysosomes and Use Protein as a Nutrient.

    Science.gov (United States)

    Wyant, Gregory A; Abu-Remaileh, Monther; Wolfson, Rachel L; Chen, Walter W; Freinkman, Elizaveta; Danai, Laura V; Vander Heiden, Matthew G; Sabatini, David M

    2017-10-19

    The mTORC1 kinase is a master growth regulator that senses many environmental cues, including amino acids. Activation of mTORC1 by arginine requires SLC38A9, a poorly understood lysosomal membrane protein with homology to amino acid transporters. Here, we validate that SLC38A9 is an arginine sensor for the mTORC1 pathway, and we uncover an unexpectedly central role for SLC38A9 in amino acid homeostasis. SLC38A9 mediates the transport, in an arginine-regulated fashion, of many essential amino acids out of lysosomes, including leucine, which mTORC1 senses through the cytosolic Sestrin proteins. SLC38A9 is necessary for leucine generated via lysosomal proteolysis to exit lysosomes and activate mTORC1. Pancreatic cancer cells, which use macropinocytosed protein as a nutrient source, require SLC38A9 to form tumors. Thus, through SLC38A9, arginine serves as a lysosomal messenger that couples mTORC1 activation to the release from lysosomes of the essential amino acids needed to drive cell growth. Copyright © 2017 Elsevier Inc. All rights reserved.

  19. Distribution of residues and primitive roots

    Indian Academy of Sciences (India)

    Replacing the function f by g, we get the required estimate for N(p, N). D. Proof of Theorem 1.1. When p = 7, we clearly see that (1, 2) is a consecutive pair of quadratic residue modulo 7. Assume that p ≥ 11. If 10 is a quadratic residue modulo p, then we have (9, 10) as a consecutive pair of quadratic residues modulo p, ...

  20. The Zygosaccharomyces bailii transcription factor Haa1 is required for acetic acid and copper stress responses suggesting subfunctionalization of the ancestral bifunctional protein Haa1/Cup2.

    Science.gov (United States)

    Palma, Margarida; Dias, Paulo Jorge; Roque, Filipa de Canaveira; Luzia, Laura; Guerreiro, Joana Fernandes; Sá-Correia, Isabel

    2017-01-13

    The food spoilage yeast species Zygosaccharomyces bailii exhibits an extraordinary capacity to tolerate weak acids, in particular acetic acid. In Saccharomyces cerevisiae, the transcription factor Haa1 (ScHaa1) is considered the main player in genomic expression reprogramming in response to acetic acid stress, but the role of its homologue in Z. bailii (ZbHaa1) is unknown. In this study it is demonstrated that ZbHaa1 is a ScHaa1 functional homologue by rescuing the acetic acid susceptibility phenotype of S. cerevisiae haa1Δ. The disruption of ZbHAA1 in Z. bailii IST302 and the expression of an extra ZbHAA1 copy confirmed ZbHAA1 as a determinant of acetic acid tolerance. ZbHaa1 was found to be required for acetic acid stress-induced transcriptional activation of Z. bailii genes homologous to ScHaa1-target genes. An evolutionary analysis of the Haa1 homologues identified in 28 Saccharomycetaceae species genome sequences, including Z bailii, was carried out using phylogenetic and gene neighbourhood approaches. Consistent with previous studies, this analysis revealed a group containing pre-whole genome duplication species Haa1/Cup2 single orthologues, including ZbHaa1, and two groups containing either Haa1 or Cup2 orthologues from post-whole genome duplication species. S. cerevisiae Cup2 (alias Ace1) is a transcription factor involved in response and tolerance to copper stress. Taken together, these observations led us to hypothesize and demonstrate that ZbHaa1 is also involved in copper-induced transcriptional regulation and copper tolerance. The transcription factor ZbHaa1 is required for adaptive response and tolerance to both acetic acid and copper stresses. The subfunctionalization of the single ancestral Haa1/Cup2 orthologue that originated Haa1 and Cup2 paralogues after whole genome duplication is proposed.

  1. Bioenergy from sisal residues

    Energy Technology Data Exchange (ETDEWEB)

    Jungersen, G. [Dansk Teknologisk Inst. (Denmark); Kivaisi, A.; Rubindamayugi, M. [Univ. of Dar es Salaam (Tanzania, United Republic of)

    1998-05-01

    The main objectives of this report are: To analyse the bioenergy potential of the Tanzanian agro-industries, with special emphasis on the Sisal industry, the largest producer of agro-industrial residues in Tanzania; and to upgrade the human capacity and research potential of the Applied Microbiology Unit at the University of Dar es Salaam, in order to ensure a scientific and technological support for future operation and implementation of biogas facilities and anaerobic water treatment systems. The experimental work on sisal residues contains the following issues: Optimal reactor set-up and performance; Pre-treatment methods for treatment of fibre fraction in order to increase the methane yield; Evaluation of the requirement for nutrient addition; Evaluation of the potential for bioethanol production from sisal bulbs. The processing of sisal leaves into dry fibres (decortication) has traditionally been done by the wet processing method, which consumes considerable quantities of water and produces large quantities of waste water. The Tanzania Sisal Authority (TSA) is now developing a dry decortication method, which consumes less water and produces a waste product with 12-15% TS, which is feasible for treatment in CSTR systems (Continously Stirred Tank Reactors). (EG)

  2. 76 FR 77709 - Butyl acrylate-methacrylic acid-styrene polymer; Tolerance Exemption

    Science.gov (United States)

    2011-12-14

    ...This regulation establishes an exemption from the requirement of a tolerance for residues of 2-Propenoic acid, 2-methyl-, polymer with butyl 2-propenoate and ethenylbenzene (CAS Reg. No. 25036-16-2); also known as butyl acrylate-methacrylic acid-styrene polymer when used as an inert ingredient in a pesticide chemical formulation. Momentive Performance Materials submitted a petition to EPA under the Federal Food, Drug, and Cosmetic Act (FFDCA), requesting an exemption from the requirement of a tolerance. This regulation eliminates the need to establish a maximum permissible level for residues of 2-Propenoic acid, 2-methyl-, polymer with butyl 2-propenoate and ethenylbenzene on food or feed commodities.

  3. Low-Level Burial Grounds dangerous waste permit application: Request for exemption from lined trench requirements and from land disposal restrictions for residual liquid at 218-E-12B Burial Ground Trench 94

    International Nuclear Information System (INIS)

    1992-10-01

    This document has been prepared and is being submitted to the respective agencies to satisfy three objectives of the US Department of Energy (DOE) Richland Field Office (DOE-RL) concerning Trench 94 of the 218-E-12B Burial Ground. The 218-E-12B Burial Ground is located in the 200 East Area of the Hanford Facility. Figure 1-1 shows the general location of the Hanford Site. The 218-E-12B Burial Ground is one of eight burial grounds included in the Low-Level Burial Grounds (LLBG), a treatment, storage and/or disposal (TSD) unit. Decommissioned, defueled naval submarine reactor compartments (SRCs) contain radioactivity caused by exposure of structural components to neutrons during normal operation of the submarines. After all the alternatives were evaluated in the US Department of the Navy 1984 environmental impact statement (EIS) (USN 1984), land burial of the SRCs was selected as the preferred disposal option. The SRCs currently are sent to Trench 94 of the 218-E-12B Burial Ground. In addition to radioactivity, the SRCs disposed in. The DOE-RL's three objectives in preparing and submitting this document are as follows. Request from Ecology an exemption from dangerous waste landfill liner and leachate collection and removal system (hereinafter referred to as liner/leachate system) requirements for Trench 94 of the 218-E-12B Burial Ground. Petition Ecology to exempt residual liquid in the SRCs from land disposal restrictions. Obtain EPA Region 10 review and comment on the request to Ecology for exemption from liner/leachate system requirements

  4. Origin of nanodiamonds from Allende constrained by statistical analysis of C isotopes from small clusters of acid residue by NanoSIMS

    Science.gov (United States)

    Lewis, Josiah B.; Floss, Christine; Gyngard, Frank

    2018-01-01

    Meteoritic nanodiamonds carry noble gases with anomalies in their stable isotopes that have drawn attention to their potentially presolar origin. Measurements of 12C/13C isotope ratios of presolar nanodiamonds are essential to understanding their origins, but bulk studies do not show notable deviations from the solar system 12C/13C ratio. We implemented a technique using secondary ion mass spectrometry with maximized spatial resolution to measure carbon isotopes in the smallest clusters of nanodiamonds possible. We measured C and Si from clusters containing as few as 1000 nanodiamonds, the smallest clusters of nanodiamonds measured to date by traditional mass spectrometry. This allowed us to investigate many possible complex compositions of the nanodiamonds, both through direct methods and statistical analysis of the distributions of observed isotopic ratios. Analysis of the breadth of distributions of carbon isotopic ratios for a number of ∼1000-nanodiamond aggregates indicates that the 12C/13C ratio may be drawn from multiple Gaussian distributions about different isotopic ratios, which implies the presence of presolar material. The mean isotopic ratio is consistent with the solar system value, so presolar components are required to be either low in concentration, or to have a mean ratio close to that of the solar system. Supernovae are likely candidates for the source of such a presolar component, although asymptotic giant branch stars are not excluded. A few aggregates show deviations from the mean 12C/13C ratio large enough to be borderline detections of enrichments in 13C. These could be caused by the presence of a small population of nanodiamonds formed from sources that produce extremely 13C-rich material, such as J-stars, novae, born-again asymptotic giant branch stars, or supernovae. Of these possible sources, only supernovae would account for the anomalous noble gases carried in the nanodiamonds.

  5. Evaluation of residue-residue contact prediction in CASP10

    KAUST Repository

    Monastyrskyy, Bohdan

    2013-08-31

    We present the results of the assessment of the intramolecular residue-residue contact predictions from 26 prediction groups participating in the 10th round of the CASP experiment. The most recently developed direct coupling analysis methods did not take part in the experiment likely because they require a very deep sequence alignment not available for any of the 114 CASP10 targets. The performance of contact prediction methods was evaluated with the measures used in previous CASPs (i.e., prediction accuracy and the difference between the distribution of the predicted contacts and that of all pairs of residues in the target protein), as well as new measures, such as the Matthews correlation coefficient, the area under the precision-recall curve and the ranks of the first correctly and incorrectly predicted contact. We also evaluated the ability to detect interdomain contacts and tested whether the difficulty of predicting contacts depends upon the protein length and the depth of the family sequence alignment. The analyses were carried out on the target domains for which structural homologs did not exist or were difficult to identify. The evaluation was performed for all types of contacts (short, medium, and long-range), with emphasis placed on long-range contacts, i.e. those involving residues separated by at least 24 residues along the sequence. The assessment suggests that the best CASP10 contact prediction methods perform at approximately the same level, and comparably to those participating in CASP9.

  6. Physicochemical and functional characteristics of residual pulp of potato

    Directory of Open Access Journals (Sweden)

    Webber Tavares de CARVALHO

    Full Text Available Abstract Starch-rich liquid effluent is generated after peeling, cutting and washing of tubers during the fries processing. After sedimentation of this effluent is recovered a wet residual pulp, and after drying is obtained dry residual pulp or simply named in this study residual pulp of potato (RPP. In order to convert the effluent into a material easy to store for long periods (such as the potato starch, which would make it suitable for various applications. The aim of this study was to evaluate the effect of the drying conditions, specifically variables temperature and air flow on the drying time and water activity, pH, titratable acidity, instrumental colour parameters, water absorption index, water solubility index and oil absorption capacity of dry RPP. Central Composite Design was used, with temperature levels from 50.0 to 70.0 °C and air flow from 0.06 to 0.092 m3 m–2 s–1. Temperature and airflow affected the study characteristics, except for lightness (L*, water solubility index and oil absorption capacity. It was concluded that milder conditions (lower temperatures and intermediate air flow resulted in higher-quality final products (lighter, less acidic, although requiring higher drying time. Therefore, depending on the product application, different drying conditions can be used.

  7. Cement production from coal conversion residues

    International Nuclear Information System (INIS)

    Brown, L.D.; Clavenna, L.R.; Eakman, J.M.; Nahas, N.C.

    1981-01-01

    Cement is produced by feeding residue solids containing carbonaceous material and ash constituents obtained from converting a carbonaceous feed material into liquids and/or gases into a cement-making zone and burning the carbon in the residue solids to supply at least a portion of the energy required to convert the solids into cement

  8. Effects of elevated atmospheric carbon dioxide concentrations on water and acid requirements of soybeans grown in a recirculating hydroponic system

    Science.gov (United States)

    Mackowiak, C. L.; Wheeler, R. M.; Lowery, W.; Sager, J. C.

    1990-01-01

    Establishing mass budgets of various crop needs, i.e. water and nutrients, in different environments is essential for the Controlled Ecological Life Support System (CELSS). The effects of CO2 (500 and 1000 umol mol (exp -1)) on water and acid use (for pH control) by soybeans in a recirculating hydroponic system were examined. Plants of cvs. McCall and Pixie were grown for 90 days using the nutrient film technique (NFT) and a nitrate based nutrient solution. System acid use for both CO2 levels peaked near 4 weeks during a phase of rapid vegetative growth, but acid use decreased more rapidly under 500 compared to 1000 umol mol (exp GR) CO2. Total system water use by 500 and 1000 umol mol (exp -1) plants was similar, leaving off at 5 weeks and declining as plants senesced (ca. 9 weeks). However, single leaf transpiration rates were consistently lower at 1000 umol mol (exp -1). The data suggest that high CO2 concentrations increase system acid (and nutrient) use because of increased vegetative growth, which in turn negates the benefit of reduced water use (lower transpiration rates) per unit leaf area.

  9. Structural requirements of the human sodium-dependent bile acid transporter (hASBT): Role of 3- and 7-OH moieties on binding and translocation of bile acids

    Science.gov (United States)

    González, Pablo M.; Lagos, Carlos F.; Ward, Weslyn C.; Polli, James E.

    2014-01-01

    Bile acids (BAs) are the end products of cholesterol metabolism. One of the critical steps in their biosynthesis involves the isomerization of the 3β-hydroxyl (-OH) group on the cholestane ring to the common 3α-configuration on BAs. BAs are actively recaptured from the small intestine by the human Apical Sodium-dependent Bile Acid Transporter (hASBT) with high affinity and capacity. Previous studies have suggested that no particular hydroxyl group on BAs is critical for binding or transport by hASBT, even though 3β-hydroxylated BAs were not examined. The aim of this study was to elucidate the role of the 3α-OH group on BAs binding and translocation by hASBT. Ten 3β-hydroxylated BAs (Iso-bile acids, iBAs) were synthesized, characterized, and subjected to hASBT inhibition and uptake studies. hASBT inhibition and uptake kinetics of iBAs were compared to that of native 3α-OH BAs. Glycine conjugates of native and isomeric BAs were subjected to molecular dynamics simulations in order to identify topological descriptors related to binding and translocation by hASBT. Iso-BAs bound to hASBT with lower affinity and exhibited reduced translocation than their respective 3α-epimers. Kinetic data suggests that, in contrast to native BAs where hASBT binding is the rate-limiting step, iBAs transport was rate-limited by translocation and not binding. Remarkably, 7-dehydroxylated iBAs were not hASBT substrates, highlighting the critical role of 7-OH group on BA translocation by hASBT, especially for iBAs. Conformational analysis of gly-iBAs and native BAs identified topological features for optimal binding as: concave steroidal nucleus, 3-OH “on-” or below-steroidal plane, 7-OH below-plane, and 12-OH moiety towards-plane. Our results emphasize the relevance of the 3α-OH group on BAs for proper hASBT binding and transport and revealed the critical role of 7-OH group on BA translocation, particularly in the absence of a 3α-OH group. Results have implications for BA

  10. Occurrence of non extractable pesticide residues in physical and chemical fractions of two soils

    Science.gov (United States)

    Andreou, Kostas; Semple, Kirk; Jones, Kevin

    2010-05-01

    Soils are considered to be a significant sink for organic contaminants, including pesticides, in the environment. Understanding the distribution and localisation of aged pesticide residues in soil is of great importance for assessing the mobility and availability of these chemicals in the environment. This study aimed to characterise the distribution of radiolabeled herbicide isoproturon and the radiolabeled insecticides diazinon and cypermethrin in two organically managed soils. The soils were spiked and aged under laboratory conditions for 17 months. The labile fraction of the pesticides residues was recovered in CaCl2 (0.01M) and then subjected to physical size fractionation using sedimentation and centrifugation steps, with >20μm, 20-2μm and 2-0.1μm soil factions collected. Further, the distribution of the pesticide residues in the organic matter of the fractionated soil was investigated using a sequential alkaline extraction (0.1N NaOH) into humic and fulvic acid and humin. Soil fractions of 20-2μm and 2-0.1μm had the largest burden of the 14C-residues. Different soil constituents have different capacities to form non-extractable residues. Soil solid fractions of 20-2 µm and 20 µm). Fulvic acid showed to play a vital role in the formation and stabilisation of non-extractable 14C-pesticide residues in most cases.Assessment of the likelihood of the pesticide residues to become available to soil biota requires an understanding of the structure of the SOM matrix and the definition of the kinetics of the pesticide residues in different SOM pools as a function of the time.

  11. Plant and yeast cornichon possess a conserved acidic motif required for correct targeting of plasma membrane cargos

    Czech Academy of Sciences Publication Activity Database

    Rosas-Santiago, P.; Lagunas-Goméz, D.; Yánez-Domínguez, C.; Vera-Estrella, R.; Zimmermannová, Olga; Sychrová, Hana; Pantoja, O.

    2017-01-01

    Roč. 1864, č. 10 (2017), s. 1809-1818 ISSN 0167-4889 R&D Projects: GA MŠk(CZ) LQ1604; GA MŠk(CZ) ED1.1.00/02.0109; GA ČR(CZ) GA17-01953S Institutional support: RVO:67985823 Keywords : cornichon * ScErv14 * acidic motif * cargo selection Subject RIV: EB - Genetics ; Molecular Biology OBOR OECD: Biochemistry and molecular biology Impact factor: 4.521, year: 2016

  12. Phospho-Rasputin Stabilization by Sec16 Is Required for Stress Granule Formation upon Amino Acid Starvation

    OpenAIRE

    Aguilera-Gomez, Angelica; Zacharogianni, Margarita; van Oorschot, Marinke M; Genau, Heide; Grond, Rianne; Veenendaal, Tineke; Sinsimer, Kristina S; Gavis, Elizabeth R; Behrends, Christian; Rabouille, Catherine

    2017-01-01

    Most cellular stresses induce protein translation inhibition and stress granule formation. Here, using Drosophila S2 cells, we investigate the role of G3BP/Rasputin in this process. In contrast to arsenite treatment, where dephosphorylated Ser142 Rasputin is recruited to stress granules, we find that, upon amino acid starvation, only the phosphorylated Ser142 form is recruited. Furthermore, we identify Sec16, a component of the endoplasmic reticulum exit site, as a Rasputin interactor and sta...

  13. Fatty acid synthase as a factor required for exercise-induced cognitive enhancement and dentate gyrus cellular proliferation.

    Directory of Open Access Journals (Sweden)

    Nataliya E Chorna

    Full Text Available Voluntary running is a robust inducer of adult hippocampal neurogenesis. Given that fatty acid synthase (FASN, the key enzyme for de novo fatty acid biosynthesis, is critically involved in proliferation of embryonic and adult neural stem cells, we hypothesized that FASN could mediate both exercise-induced cell proliferation in the subgranular zone (SGZ of the dentate gyrus (DG and enhancement of spatial learning and memory. In 20 week-old male mice, voluntary running-induced hippocampal-specific upregulation of FASN was accompanied also by hippocampal-specific accumulation of palmitate and stearate saturated fatty acids. In experiments addressing the functional role of FASN in our experimental model, chronic intracerebroventricular (i.c.v. microinfusions of C75, an irreversible FASN inhibitor, and significantly impaired exercise-mediated improvements in spatial learning and memory in the Barnes maze. Unlike the vehicle-injected mice, the C75 group adopted a non-spatial serial escape strategy and displayed delayed escape latencies during acquisition and memory tests. Furthermore, pharmacologic blockade of FASN function with C75 resulted in a significant reduction, compared to vehicle treated controls, of the number of proliferative cells in the DG of running mice as measured by immunoreactive to Ki-67 in the SGZ. Taken together, our data suggest that FASN plays an important role in exercise-mediated cognitive enhancement, which might be associated to its role in modulating exercise-induced stimulation of neurogenesis.

  14. Requirement of a Functional Flavin Mononucleotide Prenyltransferase for the Activity of a Bacterial Decarboxylase in a Heterologous Muconic Acid Pathway in Saccharomyces cerevisiae.

    Science.gov (United States)

    Weber, Heike E; Gottardi, Manuela; Brückner, Christine; Oreb, Mislav; Boles, Eckhard; Tripp, Joanna

    2017-05-15

    the importance of the strain background for the activity of a bacterial PCA decarboxylase in S. cerevisiae Inactivity of the decarboxylase is due to a nonsense mutation in a gene encoding a mitochondrial enzyme involved in the biosynthesis of a cofactor required for decarboxylase function. Our study reveals functional interchangeability of Pad1 and a bacterial homologue, irrespective of their intracellular localization. Our results open up new possibilities to improve muconic acid production by engineering cofactor supply. Furthermore, the results have important implications for the choice of the production strain. Copyright © 2017 American Society for Microbiology.

  15. Single histidine residue in head-group region is sufficient to impart remarkable gene transfection properties to cationic lipids: evidence for histidine-mediated membrane fusion at acidic pH.

    Science.gov (United States)

    Kumar, V V; Pichon, C; Refregiers, M; Guerin, B; Midoux, P; Chaudhuri, A

    2003-08-01

    Presence of endosome-disrupting multiple histidine functionalities in the molecular architecture of cationic polymers, such as polylysine, has previously been demonstrated to significantly enhance their in vitro gene delivery efficiencies. Towards harnessing improved transfection property through covalent grafting of endosome-disrupting single histidine functionality in the molecular structure of cationic lipids, herein, we report on the design, the synthesis and the transfection efficiency of two novel nonglycerol-based histidylated cationic amphiphiles. We found that L-histidine-(N,N-di-n-hexadecylamine)ethylamide (lipid 1) and L-histidine-(N,N-di-n-hexadecylamine,-N-methyl)ethylamide (lipid 2) in combination with cholesterol gave efficient transfections into various cell lines. The transfection efficiency of Chol/lipid 1 lipoplexes into HepG2 cells was two order of magnitude higher than that of FuGENE(TM)6 and DC-Chol lipoplexes, whereas it was similar into A549, 293T7 and HeLa cells. A better efficiency was obtained with Chol/lipid 2 lipoplexes when using the cytosolic luciferase expression vector (pT7Luc) under the control of the bacterial T7 promoter. Membrane fusion activity measurements using fluorescence resonance energy transfer (FRET) technique showed that the histidine head-groups of Chol/lipid 1 liposomes mediated membrane fusion in the pH range 5-7. In addition, the transgene expression results using the T7Luc expression vector convincingly support the endosome-disrupting role of the presently described mono-histidylated cationic transfection lipids and the release of DNA into the cytosol. We conclude that covalent grafting of a single histidine amino acid residue to suitable twin-chain hydrophobic compounds is able to impart remarkable transfection properties on the resulting mono-histidylated cationic amphiphile, presumably via the endosome-disrupting characteristics of the histidine functionalities.

  16. Robust GLP-1 secretion by basic L-amino acids does not require the GPRC6A receptor

    DEFF Research Database (Denmark)

    Clemmensen, Christoffer; Jørgensen, Christinna V; Smajilovic, Sanela

    2017-01-01

    (GLP-1) secretion is unclear. Therefore, to probe if the GPRC6A receptor is indispensible for amino acid-induced secretion of GLP-1, we treated, with oral gavage, GPRC6A knock-out (KO) and wild-type (WT) littermate mice with GPRC6A ligands: L-arginine and L-ornithine, and assessed GLP-1 levels...... in circulation. We found that oral administration of both L-arginine and L-ornithine significantly increased total plasma GLP-1 levels to a similar level in GPRC6A KO and WT mice 15 minutes after gavage (both amino acids) and accumulated up to 60 minutes after gavage (L-arginine). Conversely, GLP-1 secretion...... at the 30 and 60 minute time points in the KO mice were attenuated and did not reach statistical significance. In summary, these data confirm that L-arginine is a potent GLP-1 secretagogue and show that the main effect occurs independently of GPRC6A. In addition, this is the first study to show that also L...

  17. Functional group and stereochemical requirements for substrate binding by ghrelin O-acyltransferase revealed by unnatural amino acid incorporation.

    Science.gov (United States)

    Cleverdon, Elizabeth R; Davis, Tasha R; Hougland, James L

    2018-04-21

    Ghrelin is a small peptide hormone that undergoes a unique posttranslational modification, serine octanoylation, to play its physiological roles in processes including hunger signaling and glucose metabolism. Ghrelin O-acyltransferase (GOAT) catalyzes this posttranslational modification, which is essential for ghrelin to bind and activate its cognate GHS-R1a receptor. Inhibition of GOAT offers a potential avenue for modulating ghrelin signaling for therapeutic effect. Defining the molecular characteristics of ghrelin that lead to binding and recognition by GOAT will facilitate the development and optimization of GOAT inhibitors. We show that small peptide mimics of ghrelin substituted with 2,3-diaminopropanoic acid in place of the serine at the site of octanoylation act as submicromolar inhibitors of GOAT. Using these chemically modified analogs of desacyl ghrelin, we define key functional groups within the N-terminal sequence of ghrelin essential for binding to GOAT and determine GOAT's tolerance to backbone methylations and altered amino acid stereochemistry within ghrelin. Our study provides a structure-activity analysis of ghrelin binding to GOAT that expands upon activity-based investigations of ghrelin recognition and establishes a new class of potent substrate-mimetic GOAT inhibitors for further investigation and therapeutic interventions targeting ghrelin signaling. Copyright © 2018 Elsevier Inc. All rights reserved.

  18. Residual gas analysis

    International Nuclear Information System (INIS)

    Berecz, I.

    1982-01-01

    Determination of the residual gas composition in vacuum systems by a special mass spectrometric method was presented. The quadrupole mass spectrometer (QMS) and its application in thin film technology was discussed. Results, partial pressure versus time curves as well as the line spectra of the residual gases in case of the vaporization of a Ti-Pd-Au alloy were demonstrated together with the possible construction schemes of QMS residual gas analysers. (Sz.J.)

  19. Dinâmica de íons em solo ácido lixiviado com extratos de resíduos de adubos verdes e soluções puras de ácidos orgânicos Dynamic of ions in acid soil leached with green manure residues extracts and pure solutions of organic acids

    Directory of Open Access Journals (Sweden)

    Júlio Cezar Franchini

    1999-12-01

    Full Text Available A influência da aplicação de resíduos vegetais na dinâmica de íons em solos ácidos é pouco conhecida. Neste estudo, a mobilidade de íons em amostra do horizonte Bw de um Latossolo Vermelho-Escuro álico lixiviado com soluções puras de ácidos cítrico e succínico e extratos aquosos de resíduos de nabo forrageiro (Raphanus sativus e aveia-preta (Avena strigosa foi avaliada em colunas de solo (5, 10, 20 e 40 cm de altura por 4 cm de diâmetro. Após a percolação das soluções e extratos pelas colunas de solo determinaram-se, nas soluções efluentes, os teores de Ca (Ca s, Mg (Mg s, K (Ks, Al total (Al st, orgânico (Al so, monomérico (Al sm e carbono orgânico dissolvido. No solo, foram determinados os teores trocáveis de Ca (Ca tr, Mg (Mg tr, K (Ktr e Al (Al tr e o pH (CaCl2. Os ácidos cítrico e succínico aumentaram os teores de Al st e Ca s, respectivamente, causando reduções nas frações trocáveis desses elementos no solo. O extrato de aveia-preta foi mais efetivo na remoção do Ca tr e o de nabo forrageiro na do Al tr. O decréscimo de Ca tr e Al tr foi seguido do aumento do Ktr. A formação de complexos entre Ca s e Al tr com compostos orgânicos de baixo peso molecular foi sugerida como o provável mecanismo responsável pela mobilidade dos íons polivalentes no subsolo de solos ácidos após a aplicação dos extratos de resíduos vegetais e das soluções puras de ácidos orgânicos.The influence of green manure residues addition in the dynamic of ions in acid soils is not well known. In this study, ion mobility in a sample of the Bw horizon of an Dark-Red Latosol (Oxisol, leached with citric and succinic acid pure solutions and with aqueous residue extracts of black oats (Avena strigosa and oil seed radish (Raphanus sativus were evaluated in soil columns (5, 10, 20, and 40 cm long by 4 cm diameter. After the solutions and extracts passed through the soil columns, the following parameters were determined

  20. Determination of protein and amino acid requirements of lactating sows using a population-based factorial approach

    DEFF Research Database (Denmark)

    Strathe, Anja Varmløse; Strathe, Anders Bjerring; Theil, Peter Kappel

    2015-01-01

    Monte Carlo simulation techniques. BW, back fat thickness of the sow, litter size (LS), average litter gain (LG), dietary energy density and feed intake were inputs to the model. The model was tested using results from the literature, and the values were all within ±1 s.d. of the estimated requirements...... recommendations for lactating sows using a stochastic modeling approach that integrates population variation and uncertainty of key parameters into establishing nutritional recommendations for lactating sows. The requirement for individual sows was calculated using a factorial approach by adding the requirement...... for maintenance and milk. The energy balance of the sows was either negative or zero depending on feed intake being a limiting factor. Some parameters in the model were sow-specific and others were population-specific, depending on state of knowledge. Each simulation was for 1000 sows repeated 100 times using...

  1. The external gate of the human and Drosophila serotonin transporters requires a basic/acidic amino acid pair for 3,4-methylenedioxymethamphetamine (MDMA) translocation and the induction of substrate efflux.

    Science.gov (United States)

    Sealover, Natalie R; Felts, Bruce; Kuntz, Charles P; Jarrard, Rachel E; Hockerman, Gregory H; Lamb, Patrick W; Barker, Eric L; Henry, L Keith

    2016-11-15

    The substituted amphetamine, 3,4-methylenedioxy-methamphetamine (MDMA, ecstasy), is a widely used drug of abuse that induces non-exocytotic release of serotonin, dopamine, and norepinephrine through their cognate transporters as well as blocking the reuptake of neurotransmitter by the same transporters. The resulting dramatic increase in volume transmission and signal duration of neurotransmitters leads to psychotropic, stimulant, and entactogenic effects. The mechanism by which amphetamines drive reverse transport of the monoamines remains largely enigmatic, however, promising outcomes for the therapeutic utility of MDMA for post-traumatic stress disorder and the long-time use of the dopaminergic and noradrenergic-directed amphetamines in treatment of attention-deficit hyperactivity disorder and narcolepsy increases the importance of understanding this phenomenon. Previously, we identified functional differences between the human and Drosophila melanogaster serotonin transporters (hSERT and dSERT, respectively) revealing that MDMA is an effective substrate for hSERT but not dSERT even though serotonin is a potent substrate for both transporters. Chimeric dSERT/hSERT transporters revealed that the molecular components necessary for recognition of MDMA as a substrate was linked to regions of the protein flanking transmembrane domains (TM) V through IX. Here, we performed species-scanning mutagenesis of hSERT, dSERT and C. elegans SERT (ceSERT) along with biochemical and electrophysiological analysis and identified a single amino acid in TM10 (Glu394, hSERT; Asn484, dSERT, Asp517, ceSERT) that is primarily responsible for the differences in MDMA recognition. Our findings reveal that an acidic residue is necessary at this position for MDMA recognition as a substrate and serotonin releaser. Copyright © 2016 Elsevier Inc. All rights reserved.

  2. Control of instability in nitric acid evaporators for plutonium processing

    International Nuclear Information System (INIS)

    1998-03-01

    Improved control of the nitric acid process evaporators requires the detection of spontaneously unstable operating conditions. This process reduces the volume of contaminated liquid by evaporating nitric acid and concentrating salt residues. If a instability is identified quickly, prompt response can avert distillate contamination. An algorithm applied to the runtime data was evaluated to detect this situation. A snapshot of data from a histogram in the old process control software was captured during the unstable conditions and modeled

  3. [Migrants from disposable gloves and residual acrylonitrile].

    Science.gov (United States)

    Wakui, C; Kawamura, Y; Maitani, T

    2001-10-01

    Disposable gloves made from polyvinyl chloride with and without di(2-ethylhexyl) phthalate (PVC-DEHP, PVC-NP), polyethylene (PE), natural rubber (NR) and nitrile-butadiene rubber (NBR) were investigated with respect to evaporation residue, migrated metals, migrants and residual acrylonitrile. The evaporation residue found in n-heptane was 870-1,300 ppm from PVC-DEHP and PVC-NP, which was due to the plasticizers. Most of the PE gloves had low evaporation residue levels and migrants, except for the glove designated as antibacterial, which released copper and zinc into 4% acetic acid. For the NR and NBR gloves, the evaporation residue found in 4% acetic acid was 29-180 ppm. They also released over 10 ppm of calcium and 6 ppm of zinc into 4% acetic acid, and 1.68-8.37 ppm of zinc di-ethyldithiocarbamate and zinc di-n-butyldithiocarbamate used as vulcanization accelerators into n-heptane. The acrylonitrile content was 0.40-0.94 ppm in NBR gloves.

  4. Requirements of glycerol and fatty acid for triglyceride synthesis and ketogenesis by hepatocytes from normal and triiodothyronine-treated rats

    International Nuclear Information System (INIS)

    Olubadewo, J.O.; Heimberg, M.

    1985-01-01

    Hepatocytes from T3-treated rats synthesized less triglyceride and more ketone bodies from [1- 14 C]oleate at all concentrations from 0-2 mM, than did hepatocytes from euthyroid animals; addition of 1.0 mM glycerol increased triglyceride synthesis and reduced ketogenesis in hepatocytes from T3-treated rats to the rates observed in euthyroid hepatocytes in the absence of added glycerol. Glycerol did not alter triglyceride synthesis, but reduced ketogenesis genesis by euthyroid hepatocytes. It is probable from these and other data that, in the hyperthyroid rat, glycero-3-P, and not fatty acid, is rate limiting for synthesis of triglyceride, and, secondarily for reducing rates of ketogenesis in the hepatocyte

  5. Retinoic acid signalling is required for the pathogenicity of effector CD4+ T cells during the development of intestinal inflammation

    DEFF Research Database (Denmark)

    Rivollier, Aymeric Marie Christian; Pool, Lieneke; Frising, Ulrika

    The vitamin A metabolite retinoic acid (RA) seems to be a double-edge sword in CD4+ T cell biology, sustaining the development of foxp3+ Treg cells, but also being essential for the stability of the Th1 lineage. Here we explored the role of RA signalling in CD4+ T cells during the development...... of intestinal inflammation in the T cell transfer colitis model. RA signalling-deficient CD4+ T cells are less potent at inducing intestinal inflammation compared to their RA signalling-proficient counterparts and exhibit a differentiation skewing towards more IL-17+ and foxp3+ cells, while their capacity......-deficient and –proficient Tregs are equally competent to inhibit colitis development. Together our results indicate that RA, through its receptor RARα, negatively regulates the early expansion of CD4+ T cells during colitis and is necessary for the generation of colitogenic Th1/Th17 cells, while it is dispensable...

  6. Stabilization of plutonium bearing residues at Lawrence Livermore National Laboratory

    International Nuclear Information System (INIS)

    Bronson, M.C.; Van Konynenburg, R.A.; Ebbinghaus, B.B.

    1995-01-01

    The US Department of Energy's (US DOE) Lawrence Livermore National Laboratory (LLNL) has plutonium holdings including metal, oxide and residue materials, all of which need stabilization of some type. Residue materials include calcined ash, calcined precipitates, pyrochemical salts, glove box sweepings, metallurgical samples, graphite, and pyrochemical ceramic crucibles. These residues are typical of residues stored throughout the US DOE plutonium sites. The stabilization process selected for each of these residues requires data on chemical impurities, physical attributes, and chemical forms of the plutonium. This paper outlines the characterization and stabilization of LLNL ash residues, pyrochemical salts, and graphite

  7. 12 CFR 23.21 - Estimated residual value.

    Science.gov (United States)

    2010-01-01

    ... 12 Banks and Banking 1 2010-01-01 2010-01-01 false Estimated residual value. 23.21 Section 23.21...) Leases § 23.21 Estimated residual value. (a) Recovery of investment and costs. A national bank's estimate of the residual value of the property that the bank relies upon to satisfy the requirements of a full...

  8. Coevolving residues of (beta/alpha)(8)-barrel proteins play roles in stabilizing active site architecture and coordinating protein dynamics.

    Science.gov (United States)

    Shen, Hongbo; Xu, Feng; Hu, Hairong; Wang, Feifei; Wu, Qi; Huang, Qiang; Wang, Honghai

    2008-12-01

    Indole-3-glycerol phosphate synthase (IGPS) is a representative of (beta/alpha)(8)-barrel proteins-the most common enzyme fold in nature. To better understand how the constituent amino-acids work together to define the structure and to facilitate the function, we investigated the evolutionary and dynamical coupling of IGPS residues by combining statistical coupling analysis (SCA) and molecular dynamics (MD) simulations. The coevolving residues identified by the SCA were found to form a network which encloses the active site completely. The MD simulations showed that these coevolving residues are involved in the correlated and anti-correlated motions. The correlated residues are within van der Waals contact and appear to maintain the active site architecture; the anti-correlated residues are mainly distributed on opposite sides of the catalytic cavity and coordinate the motions likely required for the substrate entry and product release. Our findings might have broad implications for proteins with the highly conserved (betaalpha)(8)-barrel in assessing the roles of amino-acids that are moderately conserved and not directly involved in the active site of the (beta/alpha)(8)-barrel. The results of this study could also provide useful information for further exploring the specific residue motions for the catalysis and protein design based on the (beta/alpha)(8)-barrel scaffold.

  9. Harvesting and handling agricultural residues for energy

    Energy Technology Data Exchange (ETDEWEB)

    Jenkins, B.M.; Summer, H.R.

    1986-05-01

    Significant progress in understanding the needs for design of agricultural residue collection and handling systems has been made but additional research is required. Recommendations are made for research to (a) integrate residue collection and handling systems into general agricultural practices through the development of multi-use equipment and total harvest systems; (b) improve methods for routine evaluation of agricultural residue resources, possibly through remote sensing and image processing; (c) analyze biomass properties to obtain detailed data relevant to engineering design and analysis; (d) evaluate long-term environmental, social, and agronomic impacts of residue collection; (e) develop improved equipment with higher capacities to reduce residue collection and handling costs, with emphasis on optimal design of complete systems including collection, transportation, processing, storage, and utilization; and (f) produce standard forms of biomass fuels or products to enhance material handling and expand biomass markets through improved reliability and automatic control of biomass conversion and other utilization systems. 118 references.

  10. Characterization of residual oils for biodiesel production

    Directory of Open Access Journals (Sweden)

    Edmilson Antonio Canesin

    2014-01-01

    Conclusions: The obtained results suggesting that it is possible to take advantage of these residues for biodiesel production as the obtained products were approved according to the rules established by the National Association of Petroleum (ANP; the bovine samples were the exception regarding moisture and acidity.

  11. Protein structure based prediction of catalytic residues.

    Science.gov (United States)

    Fajardo, J Eduardo; Fiser, Andras

    2013-02-22

    Worldwide structural genomics projects continue to release new protein structures at an unprecedented pace, so far nearly 6000, but only about 60% of these proteins have any sort of functional annotation. We explored a range of features that can be used for the prediction of functional residues given a known three-dimensional structure. These features include various centrality measures of nodes in graphs of interacting residues: closeness, betweenness and page-rank centrality. We also analyzed the distance of functional amino acids to the general center of mass (GCM) of the structure, relative solvent accessibility (RSA), and the use of relative entropy as a measure of sequence conservation. From the selected features, neural networks were trained to identify catalytic residues. We found that using distance to the GCM together with amino acid type provide a good discriminant function, when combined independently with sequence conservation. Using an independent test set of 29 annotated protein structures, the method returned 411 of the initial 9262 residues as the most likely to be involved in function. The output 411 residues contain 70 of the annotated 111 catalytic residues. This represents an approximately 14-fold enrichment of catalytic residues on the entire input set (corresponding to a sensitivity of 63% and a precision of 17%), a performance competitive with that of other state-of-the-art methods. We found that several of the graph based measures utilize the same underlying feature of protein structures, which can be simply and more effectively captured with the distance to GCM definition. This also has the added the advantage of simplicity and easy implementation. Meanwhile sequence conservation remains by far the most influential feature in identifying functional residues. We also found that due the rapid changes in size and composition of sequence databases, conservation calculations must be recalibrated for specific reference databases.

  12. The plant cuticle is required for osmotic stress regulation of abscisic acid biosynthesis and osmotic stress tolerance in Arabidopsis

    KAUST Repository

    Wang, Zhenyu

    2011-05-01

    Osmotic stress activates the biosynthesis of abscisic acid (ABA). One major step in ABA biosynthesis is the carotenoid cleavage catalyzed by a 9-cis epoxycarotenoid dioxygenase (NCED). To understand the mechanism for osmotic stress activation of ABA biosynthesis, we screened for Arabidopsis thaliana mutants that failed to induce the NCED3 genee xpression in response to osmotic stress treatments. The ced1 (for 9-cis epoxycarotenoid dioxy genase defective 1) mutant isolated in this study showed markedly reduced expression of NCED3 in response to osmotic stress (polyethylene glycol)treatments compared with the wild type. Other ABA biosynthesis genes are also greatly reduced in ced1 under osmotic stress. ced1 mutant plants are very sensitive to even mild osmotic stress. Map-based cloning revealed unexpectedly thatCED1 encodes a putative a/b hydrolase domain-containing protein and is allelic to the BODYGUARD gene that was recently shown to be essential for cuticle biogenesis. Further studies discovered that other cut in biosynthesis mutants are also impaired in osmotic stress induction of ABA biosynthesis genes and are sensitive to osmotic stress. Our work demonstrates that the cuticle functions not merely as a physical barrier to minimize water loss but also mediates osmotic stress signaling and tolerance by regulating ABA biosynthesis and signaling. © 2011 American Society of Plant Biologists. All rights reserved.

  13. Retinoic Acid Signaling in B Cells Is Required for the Generation of an Effective T-Independent Immune Response.

    Science.gov (United States)

    Marks, Ellen; Ortiz, Carla; Pantazi, Eirini; Bailey, Charlotte S; Lord, Graham M; Waldschmidt, Thomas J; Noelle, Randolph J; Elgueta, Raul

    2016-01-01

    Retinoic acid (RA) plays an important role in the balance of inflammation and tolerance in T cells. Furthermore, it has been demonstrated that RA facilitates IgA isotype switching in B cells in vivo . However, it is unclear whether RA has a direct effect on T-independent B cell responses in vivo . To address this question, we generated a mouse model where RA signaling is specifically silenced in the B cell lineage. This was achieved through the overexpression of a dominant negative receptor α for RA (dnRARα) in the B cell lineage. In this model, we found a dramatic reduction in marginal zone (MZ) B cells and accumulation of transitional 2 B cells in the spleen. We also observed a reduction in B1 B cells in the peritoneum with a defect in the T-independent B cell response against 2,4,6-trinitrophenyl. This was not a result of inhibited development of B cells in the bone marrow, but likely the result of both defective expression of S1P 1 in MZ B cells and a defect in the development of MZ and B1 B cells. This suggests that RARα expression in B cells is important for B cell frequency in the MZ and peritoneum, which is crucial for the generation of T-independent humoral responses.

  14. Retinoic Acid Signaling in B Cells Is Required for the Generation of an Effective T-Independent Immune Response

    Science.gov (United States)

    Marks, Ellen; Ortiz, Carla; Pantazi, Eirini; Bailey, Charlotte S.; Lord, Graham M.; Waldschmidt, Thomas J.; Noelle, Randolph J.; Elgueta, Raul

    2016-01-01

    Retinoic acid (RA) plays an important role in the balance of inflammation and tolerance in T cells. Furthermore, it has been demonstrated that RA facilitates IgA isotype switching in B cells in vivo. However, it is unclear whether RA has a direct effect on T-independent B cell responses in vivo. To address this question, we generated a mouse model where RA signaling is specifically silenced in the B cell lineage. This was achieved through the overexpression of a dominant negative receptor α for RA (dnRARα) in the B cell lineage. In this model, we found a dramatic reduction in marginal zone (MZ) B cells and accumulation of transitional 2 B cells in the spleen. We also observed a reduction in B1 B cells in the peritoneum with a defect in the T-independent B cell response against 2,4,6-trinitrophenyl. This was not a result of inhibited development of B cells in the bone marrow, but likely the result of both defective expression of S1P1 in MZ B cells and a defect in the development of MZ and B1 B cells. This suggests that RARα expression in B cells is important for B cell frequency in the MZ and peritoneum, which is crucial for the generation of T-independent humoral responses. PMID:28066447

  15. Ethylene-Induced Inhibition of Root Growth Requires Abscisic Acid Function in Rice (Oryza sativa L.) Seedlings

    Science.gov (United States)

    He, Si-Jie; Lu, Xiang; Zhang, Wan-Ke; Lu, Tie-Gang; Chen, Shou-Yi; Zhang, Jin-Song

    2014-01-01

    Ethylene and abscisic acid (ABA) have a complicated interplay in many developmental processes. Their interaction in rice is largely unclear. Here, we characterized a rice ethylene-response mutant mhz4, which exhibited reduced ethylene-response in roots but enhanced ethylene-response in coleoptiles of etiolated seedlings. MHZ4 was identified through map-based cloning and encoded a chloroplast-localized membrane protein homologous to Arabidopsis thaliana (Arabidopsis) ABA4, which is responsible for a branch of ABA biosynthesis. MHZ4 mutation reduced ABA level, but promoted ethylene production. Ethylene induced MHZ4 expression and promoted ABA accumulation in roots. MHZ4 overexpression resulted in enhanced and reduced ethylene response in roots and coleoptiles, respectively. In root, MHZ4-dependent ABA pathway acts at or downstream of ethylene receptors and positively regulates root ethylene response. This ethylene-ABA interaction mode is different from that reported in Arabidopsis, where ethylene-mediated root inhibition is independent of ABA function. In coleoptile, MHZ4-dependent ABA pathway acts at or upstream of OsEIN2 to negatively regulate coleoptile ethylene response, possibly by affecting OsEIN2 expression. At mature stage, mhz4 mutation affects branching and adventitious root formation on stem nodes of higher positions, as well as yield-related traits. Together, our findings reveal a novel mode of interplay between ethylene and ABA in control of rice growth and development. PMID:25330236

  16. Immunomodulation by Bifidobacterium infantis 35624 in the murine lamina propria requires retinoic acid-dependent and independent mechanisms.

    Directory of Open Access Journals (Sweden)

    Patrycja Konieczna

    Full Text Available Appropriate dendritic cell processing of the microbiota promotes intestinal homeostasis and protects against aberrant inflammatory responses. Mucosal CD103(+ dendritic cells are able to produce retinoic acid from retinal, however their role in vivo and how they are influenced by specific microbial species has been poorly described. Bifidobacterium infantis 35624 (B. infantis feeding to mice resulted in increased numbers of CD103(+retinaldehyde dehydrogenase (RALDH(+ dendritic cells within the lamina propria (LP. Foxp3(+ lymphocytes were also increased in the LP, while TH1 and TH17 subsets were decreased. 3,7-dimethyl-2,6-octadienal (citral treatment of mice blocked the increase in CD103(+RALDH(+ dendritic cells and the decrease in TH1 and TH17 lymphocytes, but not the increase in Foxp3(+ lymphocytes. B. infantis reduced the severity of DSS-induced colitis, associated with decreased TH1 and TH17 cells within the LP. Citral treatment confirmed that these effects were RALDH mediated. RALDH(+ dendritic cells decreased within the LP of control inflamed animals, while RALDH(+ dendritic cells numbers were maintained in the LP of B. infantis-fed mice. Thus, CD103(+RALDH(+ LP dendritic cells are important cellular targets for microbiota-associated effects on mucosal immunoregulation.

  17. Development of sustainable precision farming systems for swine: estimating real-time individual amino acid requirements in growing-finishing pigs.

    Science.gov (United States)

    Hauschild, L; Lovatto, P A; Pomar, J; Pomar, C

    2012-07-01

    The objective of this study was to develop and evaluate a mathematical model used to estimate the daily amino acid requirements of individual growing-finishing pigs. The model includes empirical and mechanistic model components. The empirical component estimates daily feed intake (DFI), BW, and daily gain (DG) based on individual pig information collected in real time. Based on DFI, BW, and DG estimates, the mechanistic component uses classic factorial equations to estimate the optimal concentration of amino acids that must be offered to each pig to meet its requirements. The model was evaluated with data from a study that investigated the effect of feeding pigs with a 3-phase or daily multiphase system. The DFI and BW values measured in this study were compared with those estimated by the empirical component of the model. The coherence of the values estimated by the mechanistic component was evaluated by analyzing if it followed a normal pattern of requirements. Lastly, the proposed model was evaluated by comparing its estimates with those generated by the existing growth model (InraPorc). The precision of the proposed model and InraPorc in estimating DFI and BW was evaluated through the mean absolute error. The empirical component results indicated that the DFI and BW trajectories of individual pigs fed ad libitum could be predicted 1 d (DFI) or 7 d (BW) ahead with the average mean absolute error of 12.45 and 1.85%, respectively. The average mean absolute error obtained with the InraPorc for the average individual of the population was 14.72% for DFI and 5.38% for BW. Major differences were observed when estimates from InraPorc were compared with individual observations. The proposed model, however, was effective in tracking the change in DFI and BW for each individual pig. The mechanistic model component estimated the optimal standardized ileal digestible Lys to NE ratio with reasonable between animal (average CV = 7%) and overtime (average CV = 14%) variation

  18. Aqueous methods for recovery of plutonium from pyrochemical residues

    International Nuclear Information System (INIS)

    Muscatello, A.C.; Killion, M.E.; Fisher, D.C.

    1987-01-01

    Studies of the recovery of plutonium from the pyrochemical residue salts from the Direct Oxide Reduction (DOR) and Electrorefining (ER) processes have shown that chloride anion exchange is useful and effective. Our previous studies have defined the operating limits for obtaining low level effluent plutonium losses on the order of 10 -3 g/l. The knowledge obtained in work on DOR salt was extended to ER salt and a process has been demonstrated to be feasible on a larger scale. Studies of oxalate precipitation of plutonium (III) from the eluat exhibit the expected losses to the filtrate as a function of the acidity. Two alternatives to chloride anion exchange, caustic leaching and direct oxalate precipitation are also shown to be feasible for the recovery of plutonium from ER salts. The results of studies of coprocessing DOR and ER residue salts to increase ER salt throughput and decrease HC1 requirements are also presented. The feasibility of coprocessing other pyrochemical residues, such as black salts, anode heel, and ER scrapeout will be discussed

  19. T cell PPARγ is required for the anti-inflammatory efficacy of abscisic acid against experimental IBD.

    Science.gov (United States)

    Guri, Amir J; Evans, Nicholas P; Hontecillas, Raquel; Bassaganya-Riera, Josep

    2011-09-01

    The phytohormone abscisic acid (ABA) has been shown to be effective in ameliorating chronic and acute inflammation. The objective of this study was to investigate whether ABA's anti-inflammatory efficacy in the gut is dependent on peroxisome proliferator-activated receptor γ (PPARγ) in T cells. PPARγ-expressing and T cell-specific PPARγ null mice were fed diets with or without ABA (100 mg/kg) for 35 days prior to challenge with 2.5% dextran sodium sulfate. The severity of clinical disease was assessed daily, and mice were euthanized on Day 7 of the dextran sodium sulfate challenge. Colonic inflammation was assessed through macroscopic and histopathological examination of inflammatory lesions and real-time quantitative RT-PCR-based quantification of inflammatory genes. Flow cytometry was used to phenotypically characterize leukocyte populations in the blood and mesenteric lymph nodes. Colonic sections were stained immunohistochemically to determine the effect of ABA on colonic regulatory T (T(reg)) cells. ABA's beneficial effects on disease activity were completely abrogated in T cell-specific PPARγ null mice. Additionally, ABA improved colon histopathology, reduced blood F4/80(+)CD11b(+) monocytes, increased the percentage of CD4(+) T cells expressing the inhibitory molecule cytotoxic T lymphocyte antigen 4 in blood and enhanced the number of T(reg) cells in the mesenteric lymph nodes and colons of PPARγ-expressing but not T cell-specific PPARγ null mice. We conclude that dietary ABA ameliorates experimental inflammatory bowel disease by enhancing T(reg) cell accumulation in the colonic lamina propria through a PPARγ-dependent mechanism. Copyright © 2011 Elsevier Inc. All rights reserved.

  20. Demand for Zn2+ in acid-secreting gastric mucosa and its requirement for intracellular Ca2+.

    Directory of Open Access Journals (Sweden)

    JingJing Liu

    Full Text Available Recent work has suggested that Zn(2+ plays a critical role in regulating acidity within the secretory compartments of isolated gastric glands. Here, we investigate the content, distribution and demand for Zn(2+ in gastric mucosa under baseline conditions and its regulation during secretory stimulation.Content and distribution of zinc were evaluated in sections of whole gastric mucosa using X-ray fluorescence microscopy. Significant stores of Zn(2+ were identified in neural elements of the muscularis, glandular areas enriched in parietal cells, and apical regions of the surface epithelium. In in vivo studies, extraction of the low abundance isotope, (70Zn(2+, from the circulation was demonstrated in samples of mucosal tissue 24 hours or 72 hours after infusion (250 µg/kg. In in vitro studies, uptake of (70Zn(2+ from media was demonstrated in isolated rabbit gastric glands following exposure to concentrations as low as 10 nM. In additional studies, demand of individual gastric parietal cells for Zn(2+ was monitored using the fluorescent zinc reporter, fluozin-3, by measuring increases in free intracellular concentrations of Zn(2+ {[Zn(2+](i} during exposure to standard extracellular concentrations of Zn(2+ (10 µM for standard intervals of time. Under resting conditions, demand for extracellular Zn(2+ increased with exposure to secretagogues (forskolin, carbachol/histamine and under conditions associated with increased intracellular Ca(2+ {[Ca(2+](i}. Uptake of Zn(2+ was abolished following removal of extracellular Ca(2+ or depletion of intracellular Ca(2+ stores, suggesting that demand for extracellular Zn(2+ increases and depends on influx of extracellular Ca(2+.This study is the first to characterize the content and distribution of Zn(2+ in an organ of the gastrointestinal tract. Our findings offer the novel interpretation, that Ca(2+ integrates basolateral demand for Zn(2+ with stimulation of secretion of HCl into the lumen of the gastric

  1. Handling of Solid Residues

    International Nuclear Information System (INIS)

    Medina Bermudez, Clara Ines

    1999-01-01

    The topic of solid residues is specifically of great interest and concern for the authorities, institutions and community that identify in them a true threat against the human health and the atmosphere in the related with the aesthetic deterioration of the urban centers and of the natural landscape; in the proliferation of vectorial transmitters of illnesses and the effect on the biodiversity. Inside the wide spectrum of topics that they keep relationship with the environmental protection, the inadequate handling of solid residues and residues dangerous squatter an important line in the definition of political and practical environmentally sustainable. The industrial development and the population's growth have originated a continuous increase in the production of solid residues; of equal it forms, their composition day after day is more heterogeneous. The base for the good handling includes the appropriate intervention of the different stages of an integral administration of residues, which include the separation in the source, the gathering, the handling, the use, treatment, final disposition and the institutional organization of the administration. The topic of the dangerous residues generates more expectation. These residues understand from those of pathogen type that are generated in the establishments of health that of hospital attention, until those of combustible, inflammable type, explosive, radio-active, volatile, corrosive, reagent or toxic, associated to numerous industrial processes, common in our countries in development

  2. Calcination/dissolution residue treatment

    International Nuclear Information System (INIS)

    Knight, R.C.; Creed, R.F.; Patello, G.K.; Hollenberg, G.W.; Buehler, M.F.; O'Rourke, S.M.; Visnapuu, A.; McLaughlin, D.F.

    1994-09-01

    Currently, high-level wastes are stored underground in steel-lined tanks at the Hanford site. Current plans call for the chemical pretreatment of these wastes before their immobilization in stable glass waste forms. One candidate pretreatment approach, calcination/dissolution, performs an alkaline fusion of the waste and creates a high-level/low-level partition based on the aqueous solubilities of the components of the product calcine. Literature and laboratory studies were conducted with the goal of finding a residue treatment technology that would decrease the quantity of high-level waste glass required following calcination/dissolution waste processing. Four elements, Fe, Ni, Bi, and U, postulated to be present in the high-level residue fraction were identified as being key to the quantity of high-level glass formed. Laboratory tests of the candidate technologies with simulant high-level residues showed reductive roasting followed by carbonyl volatilization to be successful in removing Fe, Ni, and Bi. Subsequent bench-scale tests on residues from calcination/dissolution processing of genuine Hanford Site tank waste showed Fe was separated with radioelement decontamination factors of 70 to 1,000 times with respect to total alpha activity. Thermodynamic analyses of the calcination of five typical Hanford Site tank waste compositions also were performed. The analyses showed sodium hydroxide to be the sole molten component in the waste calcine and emphasized the requirement for waste blending if fluid calcines are to be achieved. Other calcine phases identified in the thermodynamic analysis indicate the significant thermal reconstitution accomplished in calcination

  3. gRINN: a tool for calculation of residue interaction energies and protein energy network analysis of molecular dynamics simulations.

    Science.gov (United States)

    Serçinoglu, Onur; Ozbek, Pemra

    2018-05-25

    Atomistic molecular dynamics (MD) simulations generate a wealth of information related to the dynamics of proteins. If properly analyzed, this information can lead to new insights regarding protein function and assist wet-lab experiments. Aiming to identify interactions between individual amino acid residues and the role played by each in the context of MD simulations, we present a stand-alone software called gRINN (get Residue Interaction eNergies and Networks). gRINN features graphical user interfaces (GUIs) and a command-line interface for generating and analyzing pairwise residue interaction energies and energy correlations from protein MD simulation trajectories. gRINN utilizes the features of NAMD or GROMACS MD simulation packages and automatizes the steps necessary to extract residue-residue interaction energies from user-supplied simulation trajectories, greatly simplifying the analysis for the end-user. A GUI, including an embedded molecular viewer, is provided for visualization of interaction energy time-series, distributions, an interaction energy matrix, interaction energy correlations and a residue correlation matrix. gRINN additionally offers construction and analysis of Protein Energy Networks, providing residue-based metrics such as degrees, betweenness-centralities, closeness centralities as well as shortest path analysis. gRINN is free and open to all users without login requirement at http://grinn.readthedocs.io.

  4. Identification of Key Residues for Enzymatic Carboxylate Reduction

    Directory of Open Access Journals (Sweden)

    Holly Stolterfoht

    2018-02-01

    Full Text Available Carboxylate reductases (CARs, E.C. 1.2.1.30 generate aldehydes from their corresponding carboxylic acid with high selectivity. Little is known about the structure of CARs and their catalytically important amino acid residues. The identification of key residues for carboxylate reduction provides a starting point to gain deeper understanding of enzymatic carboxylate reduction. A multiple sequence alignment of CARs with confirmed activity recently identified in our lab and from the literature revealed a fingerprint of conserved amino acids. We studied the function of conserved residues by multiple sequence alignments and mutational replacements of these residues. In this study, single-site alanine variants of Neurospora crassa CAR were investigated to determine the contribution of conserved residues to the function, expressability or stability of the enzyme. The effect of amino acid replacements was investigated by analyzing enzymatic activity of the variants in vivo and in vitro. Supported by molecular modeling, we interpreted that five of these residues are essential for catalytic activity, or substrate and co-substrate binding. We identified amino acid residues having significant impact on CAR activity. Replacement of His 237, Glu 433, Ser 595, Tyr 844, and Lys 848 by Ala abolish CAR activity, indicating their key role in acid reduction. These results may assist in the functional annotation of CAR coding genes in genomic databases. While some other conserved residues decreased activity or had no significant impact, four residues increased the specific activity of NcCAR variants when replaced by alanine. Finally, we showed that NcCAR wild-type and mutants efficiently reduce aliphatic acids.

  5. 40 CFR 180.473 - Glufosinate ammonium; tolerances for residues.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 23 2010-07-01 2010-07-01 false Glufosinate ammonium; tolerances for... § 180.473 Glufosinate ammonium; tolerances for residues. (a) General. Tolerances are established for residues of the herbicide glufosinate-ammonium (butanoic acid, 2-amino-4-(hydroxymethylphosphinyl...

  6. Thermodynamic Effects of Replacements of Pro Residues in Helix Interiors of Maltose-Binding Protein

    OpenAIRE

    Prajapati, RS; Lingaraju, GM; Bacchawat, Kiran; Surolia, Avadhesha; Varadarajan, Raghavan

    2003-01-01

    Introduction of Pro residues into helix interiors results in protein destabilization. It is currently unclear if the converse substitution (i.e., replacement of Pro residues that naturally occur in helix interiors would be stabilizing). Maltose-binding protein is a large 370-amino acid protein that contains 21 Pro residues. Of these, three nonconserved residues (P48, P133, and P159) occur at helix interiors. Each of the residues was replaced with Ala and Ser. Stabilities were characterized by...

  7. Reclamation of plutonium from pyrochemical processing residues

    International Nuclear Information System (INIS)

    Gray, L.W.; Gray, J.H.; Holcomb, H.P.; Chostner, D.F.

    1987-04-01

    Savannah River Laboratory (SRL), Savannah River Plant (SRP), and Rocky Flats Plant (RFP) have jointly developed a process to recover plutonium from molten salt extraction residues. These NaCl, KCL, and MgCl 2 residues, which are generated in the pyrochemical extraction of 241 Am from aged plutonium metal, contain up to 25 wt % dissolved plutonium and up to 2 wt % americium. The overall objective was to develop a process to convert these residues to a pure plutonium metal product and discardable waste. To meet this objective a combination of pyrochemical and aqueous unit operations was used. The first step was to scrub the salt residue with a molten metal (aluminum and magnesium) to form a heterogeneous ''scrub alloy'' containing nominally 25 wt % plutonium. This unit operation, performed at RFP, effectively separated the actinides from the bulk of the chloride salts. After packaging in aluminum cans, the ''scrub alloy'' was then dissolved in a nitric acid - hydrofluoric acid - mercuric nitrate solution at SRP. Residual chloride was separated from the dissolver solution by precipitation with Hg 2 (NO 3 ) 2 followed by centrifuging. Plutonium was then separated from the aluminum, americium and magnesium using the Purex solvent extraction system. The 241 Am was diverted to the waste tank farm, but could be recovered if desired

  8. Rpi-blb2-Mediated Hypersensitive Cell Death Caused by Phytophthora infestans AVRblb2 Requires SGT1, but not EDS1, NDR1, Salicylic Acid-, Jasmonic Acid-, or Ethylene-Mediated Signaling

    Directory of Open Access Journals (Sweden)

    Sang-Keun Oh

    2014-09-01

    Full Text Available Potato Rpi-blb2 encodes a protein with a coiled-coil-nucleotide binding site and leucine-rich repeat (CC-NBS-LRR motif that recognizes the Phytophthora infestans AVRblb2 effector and triggers hypersensitive cell death (HCD. To better understand the components required for Rpi-blb2-mediated HCD in plants, we used virus-induced gene silencing to repress candidate genes in Rpi-blb2-transgenic Nicotiana benthamiana plants and assayed the plants for AVRblb2 effector. Rpi-blb2 triggers HCD through NbSGT1-mediated pathways, but not NbEDS1- or NbNDR1-mediated pathways. In addition, the role of salicylic acid (SA, jasmonic acid (JA, and ethylene (ET in Rpi-blb2-mediated HCD were analyzed by monitoring of the responses of NbICS1-, NbCOI1-, or NbEIN2-silenced or Rpi-blb2::NahG-transgenic plants. Rpi-blb2-mediated HCD in response to AVRblb2 was not associated with SA accumulation. Thus, SA affects Rpi-blb2-mediated resistance against P. infestans, but not Rpi-blb2-mediated HCD in response to AVRblb2. Additionally, JA and ET signaling were not required for Rpi-blb2-mediated HCD in N. benthamiana. Taken together, these findings suggest that NbSGT1 is a unique positive regulator of Rpi-blb2-mediated HCD in response to AVRblb2, but EDS1, NDR1, SA, JA, and ET are not required.

  9. Characterization of Hospital Residuals

    International Nuclear Information System (INIS)

    Blanco Meza, A.; Bonilla Jimenez, S.

    1997-01-01

    The main objective of this investigation is the characterization of the solid residuals. A description of the handling of the liquid and gassy waste generated in hospitals is also given, identifying the source where they originate. To achieve the proposed objective the work was divided in three stages: The first one was the planning and the coordination with each hospital center, in this way, to determine the schedule of gathering of the waste can be possible. In the second stage a fieldwork was made; it consisted in gathering the quantitative and qualitative information of the general state of the handling of residuals. In the third and last stage, the information previously obtained was organized to express the results as the production rate per day by bed, generation of solid residuals for sampled services, type of solid residuals and density of the same ones. With the obtained results, approaches are settled down to either determine design parameters for final disposition whether for incineration, trituration, sanitary filler or recycling of some materials, and storage politics of the solid residuals that allow to determine the gathering frequency. The study concludes that it is necessary to improve the conditions of the residuals handling in some aspects, to provide the cleaning personnel of the equipment for gathering disposition and of security, minimum to carry out this work efficiently, and to maintain a control of all the dangerous waste, like sharp or polluted materials. In this way, an appreciable reduction is guaranteed in the impact on the atmosphere. (Author) [es

  10. Amino acid compositional shifts during streptophyte transitions to terrestrial habitats.

    Science.gov (United States)

    Jobson, Richard W; Qiu, Yin-Long

    2011-02-01

    Across the streptophyte lineage, which includes charophycean algae and embryophytic plants, there have been at least four independent transitions to the terrestrial habitat. One of these involved the evolution of embryophytes (bryophytes and tracheophytes) from a charophycean ancestor, while others involved the earliest branching lineages, containing the monotypic genera Mesostigma and Chlorokybus, and within the Klebsormidiales and Zygnematales lineages. To overcome heat, water stress, and increased exposure to ultraviolet radiation, which must have accompanied these transitions, adaptive mechanisms would have been required. During periods of dehydration and/or desiccation, proteomes struggle to maintain adequate cytoplasmic solute concentrations. The increased usage of charged amino acids (DEHKR) may be one way of maintaining protein hydration, while increased use of aromatic residues (FHWY) protects proteins and nucleic acids by absorbing damaging UV, with both groups of residues thought to be important for the stabilization of protein structures. To test these hypotheses we examined amino acid sequences of orthologous proteins representing both mitochondrion- and plastid-encoded proteomes across streptophytic lineages. We compared relative differences within categories of amino acid residues and found consistent patterns of amino acid compositional fluxuation in extra-membranous regions that correspond with episodes of terrestrialization: positive change in usage frequency for residues with charged side-chains, and aromatic residues of the light-capturing chloroplast proteomes. We also found a general decrease in the usage frequency of hydrophobic, aliphatic, and small residues. These results suggest that amino acid compositional shifts in extra-membrane regions of plastid and mitochondrial proteins may represent biochemical adaptations that allowed green plants to colonize the land.

  11. Residual life management. Maintenance improvement

    International Nuclear Information System (INIS)

    Sainero Garcia, J.; Hevia Ruperez, F.

    1995-01-01

    The terms Residual Life Management, Life Cycle Management and Long-Term Management are synonymous with a concept which aims to establish efficient maintenance for the profitable and safe operation of a power plant for as long as possible. A Residual Life Management programme comprises a number of stages, of which Maintenance Evaluation focuses on how power plant maintenance practices allow the mitigation and control of component ageing. with this objective in mind, a methodology has been developed for the analysis of potential degradative phenomena acting on critical components in terms of normal power plant maintenance practices. This methodology applied to maintenance evaluation enables the setting out of a maintenance programme based on the Life Management concept, and the programme's subsequent up-dating to allow for new techniques and methods. Initial applications have shown that although, in general terms, power plant maintenance is efficient, the way in which Residual Life Management is approached requires changes in maintenance practices. These changes range from modifications to existing inspection and surveillance methods or the establishment of new ones, to the monitoring of trends or the performance of additional studies, the purpose of which is to provide an accurate evaluation of the condition of the installations and the possibility of life extension. (Author)

  12. Oxidized amino acid residues in the vicinity of Q(A and Pheo(D1 of the photosystem II reaction center: putative generation sites of reducing-side reactive oxygen species.

    Directory of Open Access Journals (Sweden)

    Laurie K Frankel

    Full Text Available Under a variety of stress conditions, Photosystem II produces reactive oxygen species on both the reducing and oxidizing sides of the photosystem. A number of different sites including the Mn4O5Ca cluster, P680, PheoD1, QA, QB and cytochrome b559 have been hypothesized to produce reactive oxygen species in the photosystem. In this communication using Fourier-transform ion cyclotron resonance mass spectrometry we have identified several residues on the D1 and D2 proteins from spinach which are oxidatively modified and in close proximity to QA (D1 residues (239F, (241Q, (242E and the D2 residues (238P, (239T, (242E and (247M and PheoD1 (D1 residues (130E, (133L and (135F. These residues may be associated with reactive oxygen species exit pathways located on the reducing side of the photosystem, and their modification may indicate that both QA and PheoD1 are sources of reactive oxygen species on the reducing side of Photosystem II.

  13. The contribution of coevolving residues to the stability of KDO8P synthase.

    Directory of Open Access Journals (Sweden)

    Sharon H Ackerman

    2011-03-01

    Full Text Available The evolutionary tree of 3-deoxy-D-manno-octulosonate 8-phosphate (KDO8P synthase (KDO8PS, a bacterial enzyme that catalyzes a key step in the biosynthesis of bacterial endotoxin, is evenly divided between metal and non-metal forms, both having similar structures, but diverging in various degrees in amino acid sequence. Mutagenesis, crystallographic and computational studies have established that only a few residues determine whether or not KDO8PS requires a metal for function. The remaining divergence in the amino acid sequence of KDO8PSs is apparently unrelated to the underlying catalytic mechanism.The multiple alignment of all known KDO8PS sequences reveals that several residue pairs coevolved, an indication of their possible linkage to a structural constraint. In this study we investigated by computational means the contribution of coevolving residues to the stability of KDO8PS. We found that about 1/4 of all strongly coevolving pairs probably originated from cycles of mutation (decreasing stability and suppression (restoring it, while the remaining pairs are best explained by a succession of neutral or nearly neutral covarions.Both sequence conservation and coevolution are involved in the preservation of the core structure of KDO8PS, but the contribution of coevolving residues is, in proportion, smaller. This is because small stability gains or losses associated with selection of certain residues in some regions of the stability landscape of KDO8PS are easily offset by a large number of possible changes in other regions. While this effect increases the tolerance of KDO8PS to deleterious mutations, it also decreases the probability that specific pairs of residues could have a strong contribution to the thermodynamic stability of the protein.

  14. RABL2 Is Required for Hepatic Fatty Acid Homeostasis and Its Dysfunction Leads to Steatosis and a Diabetes-Like State.

    Science.gov (United States)

    Yi Lo, Jennifer Chi; O'Connor, Anne E; Andrews, Zane B; Lo, Camden; Tiganis, Tony; Watt, Matthew J; O'Bryan, Moira K

    2016-12-01

    Fatty liver, or hepatic steatosis, is an alarmingly common pathology in western societies, in large part because if left unheeded, it can lead to life-threatening forms of nonalcoholic fatty liver disease, including nonalcoholic steatohepatitis, fibrosis, cirrhosis, and hepatocellular carcinoma. As such, it is essential that we attain a greater understanding of the pathways that control energy partitioning in the liver and ultimately how they are impacted by environmental factors. Here, we define the essential requirement for a member of the Ras-related protein in the brain (RAB)-like (RABL) clade of small GTPases, RABL2, in fatty acid metabolism including in microtubule-associated mitochondrial movement within the liver. RABL2 dysfunction, even in mice fed a low-fat chow diet, leads to retarded hepatic mitochondria movement associated with and a cascading phenotype of interrelated metabolic defects reminiscent of a type 2 diabetic state: hepatic steatosis, insulin resistance, glucose intolerance, and adult onset obesity. RABL2 dysfunction does not, however, alter mitochondrial content, or the inherent respiratory capacity of individual mitochondria per se. Rather, it is associated with a decreased capacity for fatty oxidation in the context of the intact cell, suggesting a complex, and important, role for mitochondrial movement in metabolic health. Our data highlight the importance of RABL2 and mitochondrial dynamics in hepatic fatty acid oxidation and in the achievement of metabolic balance.

  15. Importance of uncharged polar residues and proline in the proximal two-thirds (Pro107–Ser128 of the highly conserved region of mouse ileal Na+-dependent bile acid transporter, Slc10a2, in transport activity and cellular expression

    Directory of Open Access Journals (Sweden)

    Saeki Tohru

    2013-02-01

    Full Text Available Abstract Background SLC10A2-mediated reabsorption of bile acids at the distal end of the ileum is the first step in enterohepatic circulation. Because bile acids act not only as detergents but also as signaling molecules in lipid metabolism and energy production, SLC10A2 is important as the key transporter for understanding the in vivo kinetics of bile acids. SLC10A family members and the homologous genes of various species share a highly conserved region corresponding to Gly104–Pro142 of SLC10A2. The functional importance of this region has not been fully elucidated. Results To elucidate the functional importance of this region, we previously performed mutational analysis of the uncharged polar residues and proline in the distal one-third (Thr130–Pro142 of the highly conserved region in mouse Slc10a2. In this study, proline and uncharged polar residues in the remaining two-thirds of this region in mouse Slc10a2 were subjected to mutational analysis, and taurocholic acid uptake and cell surface localization were examined. Cell surface localization of Slc10a2 is necessary for bile acid absorption. Mutants in which Asp or Leu were substituted for Pro107 (P107N or P107L were abundantly expressed, but their cell surface localization was impaired. The S126A mutant was completely impaired in cellular expression. The T110A and S128A mutants exhibited remarkably enhanced membrane expression. The S112A mutant was properly expressed at the cell surface but transport activity was completely lost. Replacement of Tyr117 with various amino acids resulted in reduced transport activity. The degree of reduction roughly depended on the van der Waals volume of the side chains. Conclusions The functional importance of proline and uncharged polar residues in the highly conserved region of mouse Slc10a2 was determined. This information will contribute to the design of bile acid-conjugated prodrugs for efficient drug delivery or SLC10A2 inhibitors for

  16. Effect of the Protection of the Residual Aminopropyl Groups of a Chiral Stationary Phase Based on (+)-(18-Crown-6)-2,3,11,12-tetracarboxylic Acid on the Chiral Resolution Behaviors

    International Nuclear Information System (INIS)

    Hyun, Myung Ho; Kim, Young Hwa; Cho, Yoon Jae

    2004-01-01

    The protection of the unreacted residual aminopropyl groups of CSP 2 was found to improve the retention and the resolution factors for the resolution of racemic compounds containing a primary amino group. However, the size of the protecting acyl group should not be too bulky. As a protecting acyl group, acetyl or butyryl group seems to be good enough for the improved retention and the improved resolution. However, the separation factors were found to decrease slightly when the unreacted residual aminopropyl groups of the CSP are protected by an acyl group.

  17. Effect of the Protection of the Residual Aminopropyl Groups of a Chiral Stationary Phase Based on (+)-(18-Crown-6)-2,3,11,12-tetracarboxylic Acid on the Chiral Resolution Behaviors

    Energy Technology Data Exchange (ETDEWEB)

    Hyun, Myung Ho; Kim, Young Hwa; Cho, Yoon Jae [Pusan National University, Busan (Korea, Republic of)

    2004-03-15

    The protection of the unreacted residual aminopropyl groups of CSP 2 was found to improve the retention and the resolution factors for the resolution of racemic compounds containing a primary amino group. However, the size of the protecting acyl group should not be too bulky. As a protecting acyl group, acetyl or butyryl group seems to be good enough for the improved retention and the improved resolution. However, the separation factors were found to decrease slightly when the unreacted residual aminopropyl groups of the CSP are protected by an acyl group.

  18. Management of NORM Residues

    International Nuclear Information System (INIS)

    2013-06-01

    The IAEA attaches great importance to the dissemination of information that can assist Member States in the development, implementation, maintenance and continuous improvement of systems, programmes and activities that support the nuclear fuel cycle and nuclear applications, and that address the legacy of past practices and accidents. However, radioactive residues are found not only in nuclear fuel cycle activities, but also in a range of other industrial activities, including: - Mining and milling of metalliferous and non-metallic ores; - Production of non-nuclear fuels, including coal, oil and gas; - Extraction and purification of water (e.g. in the generation of geothermal energy, as drinking and industrial process water; in paper and pulp manufacturing processes); - Production of industrial minerals, including phosphate, clay and building materials; - Use of radionuclides, such as thorium, for properties other than their radioactivity. Naturally occurring radioactive material (NORM) may lead to exposures at some stage of these processes and in the use or reuse of products, residues or wastes. Several IAEA publications address NORM issues with a special focus on some of the more relevant industrial operations. This publication attempts to provide guidance on managing residues arising from different NORM type industries, and on pertinent residue management strategies and technologies, to help Member States gain perspectives on the management of NORM residues

  19. In Vivo Visualizing the IFN-β Response Required for Tumor Growth Control in a Therapeutic Model of Polyadenylic-Polyuridylic Acid Administration.

    Science.gov (United States)

    Nocera, David Andrés; Roselli, Emiliano; Araya, Paula; Nuñez, Nicolás Gonzalo; Lienenklaus, Stefan; Jablonska, Jadwiga; Weiss, Siegfried; Gatti, Gerardo; Brinkmann, Melanie M; Kröger, Andrea; Morón, Gabriel; Maccioni, Mariana

    2016-03-15

    The crucial role that endogenously produced IFN-β plays in eliciting an immune response against cancer has recently started to be elucidated. Endogenous IFN-β has an important role in immune surveillance and control of tumor development. Accordingly, the role of TLR agonists as cancer therapeutic agents is being revisited via the strategy of intra/peritumoral injection with the idea of stimulating the production of endogenous type I IFN inside the tumor. Polyadenylic-polyuridylic acid (poly A:U) is a dsRNA mimetic explored empirically in cancer immunotherapy a long time ago with little knowledge regarding its mechanisms of action. In this work, we have in vivo visualized the IFN-β required for the antitumor immune response elicited in a therapeutic model of poly A:U administration. In this study, we have identified the role of host type I IFNs, cell populations that are sources of IFN-β in the tumor microenvironment, and other host requirements for tumor control in this model. One single peritumoral dose of poly A:U was sufficient to induce IFN-β, readily visualized in vivo. IFN-β production relied mainly on the activation of the transcription factor IFN regulatory factor 3 and the molecule UNC93B1, indicating that TLR3 is required for recognizing poly A:U. CD11c(+) cells were an important, but not the only source of IFN-β. Host type I IFN signaling was absolutely required for the reduced tumor growth, prolonged mice survival, and the strong antitumor-specific immune response elicited upon poly A:U administration. These findings add new perspectives to the use of IFN-β-inducing compounds in tumor therapy. Copyright © 2016 by The American Association of Immunologists, Inc.

  20. Large-scale evaluation of dynamically important residues in proteins predicted by the perturbation analysis of a coarse-grained elastic model

    Directory of Open Access Journals (Sweden)

    Tekpinar Mustafa

    2009-07-01

    Full Text Available Abstract Backgrounds It is increasingly recognized that protein functions often require intricate conformational dynamics, which involves a network of key amino acid residues that couple spatially separated functional sites. Tremendous efforts have been made to identify these key residues by experimental and computational means. Results We have performed a large-scale evaluation of the predictions of dynamically important residues by a variety of computational protocols including three based on the perturbation and correlation analysis of a coarse-grained elastic model. This study is performed for two lists of test cases with >500 pairs of protein structures. The dynamically important residues predicted by the perturbation and correlation analysis are found to be strongly or moderately conserved in >67% of test cases. They form a sparse network of residues which are clustered both in 3D space and along protein sequence. Their overall conservation is attributed to their dynamic role rather than ligand binding or high network connectivity. Conclusion By modeling how the protein structural fluctuations respond to residue-position-specific perturbations, our highly efficient perturbation and correlation analysis can be used to dissect the functional conformational changes in various proteins with a residue level of detail. The predictions of dynamically important residues serve as promising targets for mutational and functional studies.

  1. Studies on the utilization of agricultural residues in the manufacture of pulp and paper, and industrial chemicals

    Energy Technology Data Exchange (ETDEWEB)

    Joshi, V.S.; Kamath, G.P.; Basu, S.

    1980-03-15

    While demand for pulp and paper products in India is increasing at the annual rate of 7 to 8%, availability of cellulosic raw material to meet the ever increasing demand is becoming a serious problem. It has been estimated that bamboo, the traditional source of cellulosic raw material in India, even after ensuring the most scientific and best possible exploitation, could provide less than 50% of the requirement. In a big agricultural country like India, agri-residues like straws and bagasse, along with jute sticks, available in huge quantity, could provide substantial amount of cellulosic resources to the pulp and paper industry. Realizing the importance of agri-residue utilization in Indian economy, a series of research projects have been initiated and completed during the last 15 years to study the techno-economic feasibility of manufacturing pulp, paper, and industrial chemicals, based on rice and wheat straws, bagasse, and jute sticks. The economic advantages of the mechano-chemical pulping process, as compared to the conventional pressure, pulping process, for the conversion of agri-residues into pulp and paer is evaluated. For highlighting the importance of agri-residues in the field of useful chemical recovery possibilities, experimental data are given on the saccarification of agri-residues into reducing sugars by the simple acid hydrolysis method with the help of concentrated sulfuric acid.

  2. Methyl bromide residues in fumigated cocoa beans

    International Nuclear Information System (INIS)

    Adomako, D.

    1975-01-01

    The 14 C activity in unroasted [ 14 C]-methyl bromide fumigated cocoa beans was used to study the fate and persistence of CH 3 Br in the stored beans. About 70% of the residues occurred in the shells. Unchanged CH 3 Br could not be detected, all the sorbed CH 3 Br having reacted with bean constituents apparently to form 14 C-methylated derivatives and inorganic bromide. No 14 C activity was found in the lipid fraction. Roasting decreased the bound (non-volatile) residues, with corresponding changes in the activities and amounts of free sugars, free and protein amino acids. Roasted nibs and shells showed a two-fold increase in the volatile fraction of the 14 C residue. This fraction may be related to the volatile aroma compounds formed by Maillard-type reactions. (author)

  3. A non-catalytic histidine residue influences the function of the metalloprotease of Listeria monocytogenes.

    Science.gov (United States)

    Forster, Brian M; Bitar, Alan Pavinski; Marquis, Hélène

    2014-01-01

    Mpl, a thermolysin-like metalloprotease, and PC-PLC, a phospholipase C, are synthesized as proenzymes by the intracellular bacterial pathogen Listeria monocytogenes. During intracellular growth, L. monocytogenes is temporarily confined in a membrane-bound vacuole whose acidification leads to Mpl autolysis and Mpl-mediated cleavage of the PC-PLC N-terminal propeptide. Mpl maturation also leads to the secretion of both Mpl and PC-PLC across the bacterial cell wall. Previously, we identified negatively charged and uncharged amino acid residues within the N terminus of the PC-PLC propeptide that influence the ability of Mpl to mediate the maturation of PC-PLC, suggesting that these residues promote the interaction of the PC-PLC propeptide with Mpl. In the present study, we identified a non-catalytic histidine residue (H226) that influences Mpl secretion across the cell wall and its ability to process PC-PLC. Our results suggest that a positive charge at position 226 is required for Mpl functions other than autolysis. Based on the charge requirement at this position, we hypothesize that this residue contributes to the interaction of Mpl with the PC-PLC propeptide.

  4. Residual-stress measurements

    Energy Technology Data Exchange (ETDEWEB)

    Ezeilo, A N; Webster, G A [Imperial College, London (United Kingdom); Webster, P J [Salford Univ. (United Kingdom)

    1997-04-01

    Because neutrons can penetrate distances of up to 50 mm in most engineering materials, this makes them unique for establishing residual-stress distributions non-destructively. D1A is particularly suited for through-surface measurements as it does not suffer from instrumental surface aberrations commonly found on multidetector instruments, while D20 is best for fast internal-strain scanning. Two examples for residual-stress measurements in a shot-peened material, and in a weld are presented to demonstrate the attractive features of both instruments. (author).

  5. Effect of No-Clean Flux Residues on the Performance of Acrylic Conformal Coating in Aggressive Environments

    DEFF Research Database (Denmark)

    Rathinavelu, Umadevi; Jellesen, Morten S.; Møller, Per

    2012-01-01

    at various temperatures was quantified using ion chromatography by extracting the residue, and surface morphology of the residues was investigated using optical microscopy. The flux residue in general consists of both resin and activator components such as carboxylic acids. Coated samples with flux residues...