The Relationship between Perception of Academic Support Services and Persistence and Integration of Undeclared Students

ERIC Educational Resources Information Center

Reiner, Virginia

2012-01-01

Improving retention remains a major objective of institutions of higher education. Retaining at-risk students has proved particularly challenging and increasingly important because often these students are members of underrepresented populations, such as first generation and minority students, among others. Undeclared students may be at increased…

Amino Acid Oxidation Increases with Dietary Protein Content in Adult Neutered Male Cats as Measured Using [1-13C]Leucine and [15N2]Urea.

PubMed

Wester, Timothy J; Weidgraaf, Karin; Hekman, Margreet; Ugarte, Claudia E; Forsyth, Sandra F; Tavendale, Michael H

2015-11-01

Cats are unique among domestic animals in that they are obligate carnivores and have a high protein requirement. However, there are few data on protein turnover and amino acid (AA) metabolism in cats. The aim of this study was to examine the effects of dietary protein content on urea production and Leu metabolism in cats. Eighteen neutered male cats (4.4 ± 0.11 kg body weight, aged 4.6 ± 0.41 y) fed to maintain body weight for 3 wk with 15%, 40%, or 65% metabolizable energy intake as crude protein (CP) had [1-(13)C]Leu administered in the fed state. Urea production was measured by the infusion of [(15)N2]urea. Leu flux, nonoxidative Leu disposal (NOLD; protein synthesis), Leu rate of appearance (Ra; protein degradation), and Leu oxidation were determined. Urea production and Leu oxidation were both ∼ 3 times greater in cats fed 65% CP compared with those fed 15% CP, whereas those fed 40% CP were ∼ 1.6 times greater (P < 0.05). Leu flux was 1.9 and 1.3 times greater in cats fed 65% CP compared with those fed 15% and 40% CP (P < 0.001). Almost 39% of total Leu flux was oxidized by cats fed 15% CP, whereas this increased to 58% in cats fed 65% CP (P < 0.002). There were no differences for Ra, but cats fed 65% CP tended to have 30% greater NOLD (P = 0.09) and to be in positive protein balance (P = 0.08) compared with those fed 15% CP. The high protein requirement of cats combined with a low rate of whole-body protein synthesis ensures that an obligate demand of AAs for energy or glucose (or both) can be met in an animal that evolved with a diet high in protein with very little or no carbohydrate. © 2015 American Society for Nutrition.

Influence of an Academic Workshop on Once-Undeclared Graduates' Selection of a Major

ERIC Educational Resources Information Center

Legutko, Robert S.

2007-01-01

This study determined the influence of an academic workshop on appropriate declaration of a major for students who graduated, but were previously undeclared, at one small, private, urban, coeducational, religiously-affiliated, four-year, commuter college in the mid-Atlantic region of the United States. A posttest only control group design revealed…

Immunochemical-based method for detection of hazelnut proteins in processed foods.

PubMed

Ben Rejeb, Samuel; Abbott, Michael; Davies, David; Querry, Jessica; Cléroux, Chantal; Streng, Christine; Delahaut, Philippe; Yeung, Jupiter M

2003-01-01

A competitive enzyme-linked immunosorbent assay (ELISA) was developed to detect hazelnut by using polyclonal antibodies generated against a protein extract of roasted hazelnut. No cross-reactivity was observed in tests against 39 commodities, including many common allergens, tree nuts, and legumes. Hazelnut protein standard solutions at 0.45 ng/mL [inhibition concentration (IC80) of the competitive test] were clearly identified by the ELISA. An extraction and quantification method was developed and optimized for chocolate, cookies, breakfast cereals, and ice cream, major food commodities likely to be cross-contaminated with undeclared hazelnut during food processing. No sample cleanup was required when extracts were diluted 10-fold. Recovery results were generated with blank matrixes spiked at 4 levels from 1 to 10 microg/g hazelnut protein. With the developed extraction and sample handling procedure, hazelnut proteins were recovered at 64-83% from chocolate and at 78-97% from other matrixes. A confirmatory technique was developed with sodium dodecyl sulfate-polyacrylamide gel electrophoresis and Western transfer. The developed methods were applied to a small market survey of chocolate products and allowed the identification of undeclared hazelnut in these products.

Partial restoration of impaired interleukin-2 production and Tac antigen (putative interleukin-2 receptor) expression in patients with acquired immune deficiency syndrome by isoprinosine treatment in vitro.

PubMed Central

Tsang, K Y; Fudenberg, H H; Galbraith, G M; Donnelly, R P; Bishop, L R; Koopmann, W R

1985-01-01

The in vitro effects of isoprinosine (ISO) on interleukin-2 (IL-2) production, the expression of Tac antigen (IL-2 receptor) on lymphocytes, and the ability of Leu 3(+) cells to absorb interleukin-1 (IL-1) were investigated in 10 patients with acquired immune deficiency syndrome (AIDS). In 9 of the 10 patients, production of IL-2 from mononuclear cells and Leu 3(+) cells was depressed; expression of Tac antigen on mononuclear cells and Leu 2(+) cells was found to be depressed in 9 of 10 patients. The ability of the Leu 3(+) lymphocytes to absorb IL-1 was depressed in all (four of four) patients studied. After ISO treatment, IL-2 production, Tac antigen expression and IL-1 absorption were restored to normal or near normal levels in most of the patients. These results suggest that ISO has an immunostimulating capacity in AIDS patients and that the potential of ISO in immune response restoration in AIDS patients deserves critical consideration. PMID:2581997

Technical solutions to nonproliferation challenges

NASA Astrophysics Data System (ADS)

Satkowiak, Lawrence

2014-05-01

The threat of nuclear terrorism is real and poses a significant challenge to both U.S. and global security. For terrorists, the challenge is not so much the actual design of an improvised nuclear device (IND) but more the acquisition of the special nuclear material (SNM), either highly enriched uranium (HEU) or plutonium, to make the fission weapon. This paper provides two examples of technical solutions that were developed in support of the nonproliferation objective of reducing the opportunity for acquisition of HEU. The first example reviews technologies used to monitor centrifuge enrichment plants to determine if there is any diversion of uranium materials or misuse of facilities to produce undeclared product. The discussion begins with a brief overview of the basics of uranium processing and enrichment. The role of the International Atomic Energy Agency (IAEA), its safeguard objectives and how the technology evolved to meet those objectives will be described. The second example focuses on technologies developed and deployed to monitor the blend down of 500 metric tons of HEU from Russia's dismantled nuclear weapons to reactor fuel or low enriched uranium (LEU) under the U.S.-Russia HEU Purchase Agreement. This reactor fuel was then purchased by U.S. fuel fabricators and provided about half the fuel for the domestic power reactors. The Department of Energy established the HEU Transparency Program to provide confidence that weapons usable HEU was being blended down and thus removed from any potential theft scenario. Two measurement technologies, an enrichment meter and a flow monitor, were combined into an automated blend down monitoring system (BDMS) and were deployed to four sites in Russia to provide 24/7 monitoring of the blend down. Data was downloaded and analyzed periodically by inspectors to provide the assurances required.

Technical solutions to nonproliferation challenges

DOE Office of Scientific and Technical Information (OSTI.GOV)

Satkowiak, Lawrence

2014-05-09

The threat of nuclear terrorism is real and poses a significant challenge to both U.S. and global security. For terrorists, the challenge is not so much the actual design of an improvised nuclear device (IND) but more the acquisition of the special nuclear material (SNM), either highly enriched uranium (HEU) or plutonium, to make the fission weapon. This paper provides two examples of technical solutions that were developed in support of the nonproliferation objective of reducing the opportunity for acquisition of HEU. The first example reviews technologies used to monitor centrifuge enrichment plants to determine if there is any diversionmore » of uranium materials or misuse of facilities to produce undeclared product. The discussion begins with a brief overview of the basics of uranium processing and enrichment. The role of the International Atomic Energy Agency (IAEA), its safeguard objectives and how the technology evolved to meet those objectives will be described. The second example focuses on technologies developed and deployed to monitor the blend down of 500 metric tons of HEU from Russia's dismantled nuclear weapons to reactor fuel or low enriched uranium (LEU) under the U.S.-Russia HEU Purchase Agreement. This reactor fuel was then purchased by U.S. fuel fabricators and provided about half the fuel for the domestic power reactors. The Department of Energy established the HEU Transparency Program to provide confidence that weapons usable HEU was being blended down and thus removed from any potential theft scenario. Two measurement technologies, an enrichment meter and a flow monitor, were combined into an automated blend down monitoring system (BDMS) and were deployed to four sites in Russia to provide 24/7 monitoring of the blend down. Data was downloaded and analyzed periodically by inspectors to provide the assurances required.« less

Survey of undeclared egg allergen levels in the most frequently recalled food types (including products bearing precautionary labelling).

PubMed

Khuda, Sefat E; Sharma, Girdhari M; Gaines, Dennis; Do, Andrew B; Pereira, Marion; Chang, Michael; Ferguson, Martine; Williams, Kristina M

2016-08-01

Since the number of recalls involving undeclared allergens is commonly associated with bakery and snack foods, we aimed to determine the frequency of egg allergens in a large number of these products using two commercial enzyme-linked immunosorbent assay (ELISA) methods. Samples were chosen that either had no egg identified on the product label or which had an egg precautionary statement. Among all samples, egg protein was detected in 5% of products using a Morinaga (MO) kit and 1% of products using a R-Biopharm (RB) kit. For bakery samples, egg protein was detected in 6% of 363 samples with no precautionary labelling (6% by MO and 1% by RB kit) and 12% of 80 samples which had precautionary labelling. For snack samples, egg protein was detected in 2% of 371 samples with no precautionary labelling (2% by MO and < 1% by RB kit) and 5% of 21 samples which had precautionary labelling. The disagreement rates between two methods were 5.2% for bakery products and 2.6% for snack products. The sample repeatability was at an acceptable level for bakery (< 12.5%) and snack foods (< 7.5%) for each method. The relative standard deviation between test kits was high (103.1%) for bakery foods. Four bakery products without precautionary labelling had a higher level of egg protein per serving compared with the eliciting dose (ED10 of 3.7 mg protein) for egg allergic patients. These results highlight the fact that detection methodology plays a vital role for accurate labelling control and mitigation of risk for egg allergic consumers.

Processing of LEU targets for {sup 99}Mo production--testing and modification of the Cintichem process

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wu, D.; Landsberger, S.; Buchholz, B.

1995-09-01

Recent experimental results on testing and modification of the Cintichem process to allow substitution of low enriched uranium (LEU) for high enriched uranium (HEU) targets are presented in this report. The main focus is on {sup 99}Mo recovery and purification by its precipitation with {alpha}-benzoin oxime. Parameters that were studied include concentrations of nitric and sulfuric acids, partial neutralization of the acids, molybdenum and uranium concentrations, and the ratio of {alpha}-benzoin oxime to molybdenum. Decontamination factors for uranium, neptunium, and various fission products were measured. Experiments with tracer levels of irradiated LEU were conducted for testing the {sup 99}Mo recoverymore » and purification during each step of the Cintichem process. Improving the process with additional processing steps was also attempted. The results indicate that the conversion of molybdenum chemical processing from HEU to LEU targets is possible.« less

Preproghrelin Leu72Met polymorphism in patients with type 2 diabetes mellitus.

PubMed

Ukkola, O; Kesäniemi, Y A

2003-10-01

The association between the Leu72Met polymorphism of the preproghrelin gene and diabetic complications was examined in patients with type 2 diabetes mellitus. A total of 258 patients with type 2 diabetes mellitus and 522 control subjects were screened. Genotypes were determined by polymerase chain reaction technique. The diagnosis of coronary heart disease was based on clinical and ECG criteria. Laboratory analyses were carried out in the hospital laboratory. No differences in the genotype distributions and allele frequencies of the preproghrelin Leu72Met polymorphism were found between type 2 diabetes mellitus patients and controls. The polymorphism was not associated with macro- or micro-angiopathy or hypertension. However, Leu72Met polymorphism was associated with serum creatinine (P = 0.006) and lipoprotein(a) [Lp(a)] levels (P = 0.006) with Leu72Leu subjects showing the highest values. This association was observed only amongst diabetic group. The Leu72Met polymorphism of the preproghrelin gene was not related to cardiovascular disease in type 2 diabetes mellitus patients. Leu72Met polymorphism was, however, associated with serum creatinine and Lp(a) levels in diabetic patients. The mechanism might be associated with a possible change in ghrelin product and its somatotropic effect.

Analysis and critical comparison of food allergen recalls from the European Union, USA, Canada, Hong Kong, Australia and New Zealand.

PubMed

Bucchini, Luca; Guzzon, Antonella; Poms, Roland; Senyuva, Hamide

2016-05-01

As part of a European Union-funded project (FP7) developing 'Integrated approaches to food allergen and allergy management', a database was constructed based on publicly available information on food allergen recalls in Europe, North America, Hong Kong, Australia and New Zealand. Over 2000 entries were made into the database. The database covers a 4-year period from 2011 to 2014 and each entry is categorised into food type (two different classifications), identified allergen and cause where indicated by the authorities. Across different authorities, by far the biggest incidence of undeclared allergens occurred in the food categories of prepared dishes and snacks (range = 12-53%), and cereals and bakery products (range = 14-25% of all recalls and/or alerts). The biggest incidence of undeclared allergens, according to the information from most authorities, occurred for milk and milk products (16-31% of all products with recall or alert), followed by cereals containing gluten (9-19%), soy (5-45%), and egg and egg products (5-17%). Although 42-90% of the products with recalls/alerts were explained as being 'Not indicated on the label', this is a generic explanation of cause and does not provide much insight into the causes of the recall/alerts. However, 0-17% of products with recalls/alerts could be coded as caused by the unintended presence of an allergen as the probable result of cross-contact in production. Construction of the database of allergen recalls has provided some important lessons and recommendations to the authorities are made in this paper in terms of the harmonisation of the reporting of allergen recalls into a more standardised format.

Controlling Pu behavior on Titania: Implications for LEU Fission-Based Mo-99 Production

DOE Office of Scientific and Technical Information (OSTI.GOV)

Youker, Amanda J.; Brown, M. Alex; Heltemes, Thad A.

Molybdenum-99 is the parent isotope of the most widely used isotope, technetium-99m, in all diagnostic nuclear medicine procedures. Due to proliferation concerns associated with the use of highly enriched uranium (HEU), the preferred method of fission-based Mo-99 production uses low enriched uranium (LEU) targets. Using LEU versus HEU for Mo-99 production produces similar to 30 times more Pu-239, due to neutron capture on U-238 to produce Np-239, which ultimately decays to Pu-239 (t(1/2) = 24,110 yr). Argonne National Laboratory is supporting a potential US Mo-99 producer in their efforts to produce Mo-99 from an LEU solution. In order to mitigatemore » the generation of large volumes of greater-than-class-C (GTCC) low level waste (Pu-239 concentrations greater than 1 nCi/g), we have focused our efforts on the separation chemistry of Pu and Mo with a titania sorbent in sulfate media. Results from batch and column experiments show that temperature and acid wash concentration can be used to control Pu behavior on titania.« less

Enhancement of L-valine production in Bacillus licheniformis by blocking three branched pathways.

PubMed

Liang, Chengwen; Huo, Yanli; Qi, Gaofu; Wei, Xuetuan; Wang, Qin; Chen, Shouwen

2015-06-01

Bacillus licheniformis WX-02 is used for the production of many valuable chemicals. Here, we have sought to improve L-valine production by blocking the metabolic pathways related to branched-chain amino acids. The synthesis genes of L-leucine (leuA) and L-isoleucine (ilvA) were deleted to obtain mutant strains. L-Valine yields of WX-02ΔleuA and WX-02ΔilvA reached 33.2 and 21.1 mmol/l, respectively, which are 22 and 14 times higher than the wild-type WX-02 (1.53 mmol/l). After further deletion of L-lactate dehydrogenase gene (ldh) from WX-02ΔleuA, the productivity reached 0.47 mmol/l h, an increase of 19 %. We provide a possibility to over-produce L-valine using genetically-modified B. licheniformis using remodeling of the biosynthetic pathway to L-valine.

Integrating multi-omics analyses of Nonomuraea dietziae to reveal the role of soybean oil in [(4'-OH)MeLeu]4-CsA overproduction.

PubMed

Liu, Huanhuan; Huang, Di; Jin, Lina; Wang, Cheng; Liang, Shaoxiong; Wen, Jianping

2017-07-14

Nonomuraea dietziae is a promising microorganism to mediate the region-specific monooxygenation reaction of cyclosporine A (CsA). The main product [(4'-OH)MeLeu] 4 -CsA possesses high anti-HIV/HCV and hair growth-stimulating activities while avoiding the immunosuppressive effect of CsA. However, the low conversion efficiency restricts the clinical application. In this study, the production of [(4'-OH)MeLeu] 4 -CsA was greatly improved by 55.6% from 182.8 to 284.4 mg/L when supplementing soybean oil into the production medium, which represented the highest production of [(4'-OH)MeLeu] 4 -CsA so far. To investigate the effect of soybean oil on CsA conversion, some other plant oils (corn oil and peanut oil) and the major hydrolysates of soybean oil were fed into the production medium, respectively. The results demonstrated that the plant oils, rather than the hydrolysates, could significantly improve the [(4'-OH)MeLeu] 4 -CsA production, suggesting that soybean oil might not play its role in the lipid metabolic pathway. To further unveil the mechanism of [(4'-OH)MeLeu] 4 -CsA overproduction under the soybean oil condition, a proteomic analysis based on the two-dimensional gel electrophoresis coupled with MALDI TOF/TOF mass spectrometry was implemented. The results showed that central carbon metabolism, genetic information processing and energy metabolism were significantly up-regulated under the soybean oil condition. Moreover, the gas chromatography-mass spectrometry-based metabolomic analysis indicated that soybean oil had a great effect on amino acid metabolism and tricarboxylic acid cycle. In addition, the transcription levels of cytochrome P450 hydroxylase (CYP) genes for CsA conversion were determined by RT-qPCR and the results showed that most of the CYP genes were up-regulated under the soybean oil condition. These findings indicate that soybean oil could strengthen the primary metabolism and the CYP system to enhance the mycelium growth and the monooxygenation reaction, respectively, and it will be a guidance for the further metabolic engineering of this strain.

Cathepsin-mediated Necrosis Controls the Adaptive Immune Response by Th2 (T helper type 2)-associated Adjuvants*

PubMed Central

Jacobson, Lee S.; Lima, Heriberto; Goldberg, Michael F.; Gocheva, Vasilena; Tsiperson, Vladislav; Sutterwala, Fayyaz S.; Joyce, Johanna A.; Gapp, Bianca V.; Blomen, Vincent A.; Chandran, Kartik; Brummelkamp, Thijn R.; Diaz-Griffero, Felipe; Brojatsch, Jürgen

2013-01-01

Immunologic adjuvants are critical components of vaccines, but it remains unclear how prototypical adjuvants enhance the adaptive immune response. Recent studies have shown that necrotic cells could trigger an immune response. Although most adjuvants have been shown to be cytotoxic, this activity has traditionally been considered a side effect. We set out to test the role of adjuvant-mediated cell death in immunity and found that alum, the most commonly used adjuvant worldwide, triggers a novel form of cell death in myeloid leukocytes characterized by cathepsin-dependent lysosome-disruption. We demonstrated that direct lysosome-permeabilization with a soluble peptide, Leu-Leu-OMe, mimics the alum-like form of necrotic cell death in terms of cathepsin dependence and cell-type specificity. Using a combination of a haploid genetic screen and cathepsin-deficient cells, we identified specific cathepsins that control lysosome-mediated necrosis. We identified cathepsin C as critical for Leu-Leu-OMe-induced cell death, whereas cathepsins B and S were required for alum-mediated necrosis. Consistent with a role of necrotic cell death in adjuvant effects, Leu-Leu-OMe replicated an alum-like immune response in vivo, characterized by dendritic cell activation, granulocyte recruitment, and production of Th2-associated antibodies. Strikingly, cathepsin C deficiency not only blocked Leu-Leu-OMe-mediated necrosis but also impaired Leu-Leu-OMe-enhanced immunity. Together our findings suggest that necrotic cell death is a powerful mediator of a Th2-associated immune response. PMID:23297415

PDRD (SR13046) TRITIUM PRODUCTION FINAL REPORT

DOE Office of Scientific and Technical Information (OSTI.GOV)

Smith, P.; Sheetz, S.

Utilizing the results of Texas A&M University (TAMU) senior design projects on tritium production in four different small modular reactors (SMR), the Savannah River National Laboratory’s (SRNL) developed an optimization model evaluating tritium production versus uranium utilization under a FY2013 plant directed research development (PDRD) project. The model is a tool that can evaluate varying scenarios and various reactor designs to maximize the production of tritium per unit of unobligated United States (US) origin uranium that is in limited supply. The primary module in the model compares the consumption of uranium for various production reactors against the base case ofmore » Watts Bar I running a nominal load of 1,696 tritium producing burnable absorber rods (TPBARs) with an average refueling of 41,000 kg low enriched uranium (LEU) on an 18 month cycle. After inputting an initial year, starting inventory of unobligated uranium and tritium production forecast, the model will compare and contrast the depletion rate of the LEU between the entered alternatives. This is an annual tritium production rate of approximately 0.059 grams of tritium per kilogram of LEU (g-T/kg-LEU). To date, the Nuclear Regulatory Commission (NRC) license has not been amended to accept a full load of TPBARs so the nominal tritium production has not yet been achieved. The alternatives currently loaded into the model include the three light water SMRs evaluated in TAMU senior projects including, mPower, Holtec and NuScale designs. Initial evaluations of tritium production in light water reactor (LWR) based SMRs using optimized loads TPBARs is on the order 0.02-0.06 grams of tritium per kilogram of LEU used. The TAMU students also chose to model tritium production in the GE-Hitachi SPRISM, a pooltype sodium fast reactor (SFR) utilizing a modified TPBAR type target. The team was unable to complete their project so no data is available. In order to include results from a fast reactor, the SRNL Technical Advisory Committee (TAC) ran a Monte Carlo N-Particle (MCNP) model of a basic SFR for comparison. A 600MWth core surrounded by a lithium blanket produced approximately 1,000 grams of tritium annually with a 13% enriched, 6 year core. This is similar results to a mid-1990’s study where the Fast Flux Test Facility (FFTF), a 400 MWth reactor at the Idaho National Laboratory (INL), could produce about 1,000 grams with an external lithium target. Normalized to the LWRs values, comparative tritium production for an SFR could be approximately 0.31 g-T/kg LEU.« less

Progress and status of the IAEA coordinated research project: production of Mo-99 using LEU fission or neutron activation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Goldman, Ira N.; Adelfang, Pablo; Ramamoorthy, Natesan

2008-07-15

Since late 2004, the IAEA has developed and implemented a Coordinated Research Project (CRP) to assist countries interested in initiating indigenous, small-scale production of Mo-99 to meet local nuclear medicine requirements. The objective of the CRP is to provide interested countries with access to non-proprietary technologies and methods to produce Mo-99 using LEU foil or LEU mini-plate targets, or for the utilization of n,gamma neutron activation, e.g. through the use of gel generators. The project has made further progress since the RERTR 2006 meeting, with a Technical Workshop on Operational Aspects of Mo99 Production held 28-30 November 2006 in Viennamore » and the Second Research Coordination Meeting held in Bucharest, Romania 16-20 April 2007. The paper describes activities carried out as noted above, and as well as the provision of LEU foils to a number of participants, and the progress by a number of groups in preparing for LEU target assembly and disassembly, irradiation, chemical processing, and waste management. The participants' progress in particular on thermal hydraulics computations required for using LEU targets is notable, as also the progress in gel generator plant operations in India and Kazakhstan. Poland has joined as a new research agreement holder and an application by Egypt to be a contract holder is undergoing internal review in the IAEA and is expected to be approved. The IAEA has also participated in several open meetings of the U.S. National Academy of Sciences Study on Producing Medical Radioisotopes without HEU, which will also be discussed in the paper. (author)« less

Impact of the High Flux Isotope Reactor HEU to LEU Fuel Conversion on Cold Source Nuclear Heat Generation Rates

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chandler, David

2014-03-01

Under the sponsorship of the US Department of Energy National Nuclear Security Administration, staff members at the Oak Ridge National Laboratory have been conducting studies to determine whether the High Flux Isotope Reactor (HFIR) can be converted from high enriched uranium (HEU) fuel to low enriched uranium (LEU) fuel. As part of these ongoing studies, an assessment of the impact that the HEU to LEU fuel conversion has on the nuclear heat generation rates in regions of the HFIR cold source system and its moderator vessel was performed and is documented in this report. Silicon production rates in the coldmore » source aluminum regions and few-group neutron fluxes in the cold source moderator were also estimated. Neutronics calculations were performed with the Monte Carlo N-Particle code to determine the nuclear heat generation rates in regions of the HFIR cold source and its vessel for the HEU core operating at a full reactor power (FP) of 85 MW(t) and the reference LEU core operating at an FP of 100 MW(t). Calculations were performed with beginning-of-cycle (BOC) and end-of-cycle (EOC) conditions to bound typical irradiation conditions. Average specific BOC heat generation rates of 12.76 and 12.92 W/g, respectively, were calculated for the hemispherical region of the cold source liquid hydrogen (LH2) for the HEU and LEU cores, and EOC heat generation rates of 13.25 and 12.86 W/g, respectively, were calculated for the HEU and LEU cores. Thus, the greatest heat generation rates were calculated for the EOC HEU core, and it is concluded that the conversion from HEU to LEU fuel and the resulting increase of FP from 85 MW to 100 MW will not impact the ability of the heat removal equipment to remove the heat deposited in the cold source system. Silicon production rates in the cold source aluminum regions are estimated to be about 12.0% greater at BOC and 2.7% greater at EOC for the LEU core in comparison to the HEU core. Silicon is aluminum s major transmutation product and affects mechanical properties of aluminum including density, neutron irradiation hardening, swelling, and loss of ductility. Because slightly greater quantities of silicon will be produced in the cold source moderator vessel for the LEU core, these effects will be slightly greater for the LEU core than for the HEU core. Three-group (thermal, epithermal, and fast) neutron flux results tallied in the cold source LH2 hemisphere show greater values for the LEU core under both BOC and EOC conditions. The thermal neutron flux in the LH2 hemisphere for the LEU core is about 12.4% greater at BOC and 2.7% greater at EOC than for the HEU core. Therefore, cold neutron scattering will not be adversely affected and the 4 12 neutrons conveyed to the cold neutron guide hall for research applications will be enhanced.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bakel, Allen J.; Conner, Cliff; Quigley, Kevin

One of the missions of the Reduced Enrichment for Research and Test Reactors (RERTR) program (and now the National Nuclear Security Administrations Material Management and Minimization program) is to facilitate the use of low enriched uranium (LEU) targets for 99Mo production. The conversion from highly enriched uranium (HEU) to LEU targets will require five to six times more uranium to produce an equivalent amount of 99Mo. The work discussed here addresses the technical challenges encountered in the treatment of uranyl nitrate hexahydrate (UNH)/nitric acid solutions remaining after the dissolution of LEU targets. Specifically, the focus of this work is themore » calcination of the uranium waste from 99Mo production using LEU foil targets and the Modified Cintichem Process. Work with our calciner system showed that high furnace temperature, a large vent tube, and a mechanical shield are beneficial for calciner operation. One- and two-step direct calcination processes were evaluated. The high-temperature one-step process led to contamination of the calciner system. The two-step direct calcination process operated stably and resulted in a relatively large amount of material in the calciner cup. Chemically assisted calcination using peroxide was rejected for further work due to the difficulty in handling the products. Chemically assisted calcination using formic acid was rejected due to unstable operation. Chemically assisted calcination using oxalic acid was recommended, although a better understanding of its chemistry is needed. Overall, this work showed that the two-step direct calcination and the in-cup oxalic acid processes are the best approaches for the treatment of the UNH/nitric acid waste solutions remaining from dissolution of LEU targets for 99Mo production.« less

Vibrio cholerae ToxR downregulates virulence factor production in response to cyclo(Phe-Pro).

PubMed

Bina, X Renee; Taylor, Dawn L; Vikram, Amit; Ante, Vanessa M; Bina, James E

2013-08-27

Vibrio cholerae is an aquatic organism that causes the severe acute diarrheal disease cholera. The ability of V. cholerae to cause disease is dependent upon the production of two critical virulence determinants, cholera toxin (CT) and the toxin-coregulated pilus (TCP). The expression of the genes that encode for CT and TCP production is under the control of a hierarchical regulatory system called the ToxR regulon, which functions to activate virulence gene expression in response to in vivo stimuli. Cyclic dipeptides have been found to be produced by numerous bacteria, yet their biological function remains unknown. V. cholerae has been shown to produce cyclo(Phe-Pro). Previous studies in our laboratory demonstrated that cyclo(Phe-Pro) inhibited V. cholerae virulence factor production. For this study, we report on the mechanism by which cyclo(Phe-Pro) inhibited virulence factor production. We have demonstrated that exogenous cyclo(Phe-Pro) activated the expression of leuO, a LysR-family regulator that had not been previously associated with V. cholerae virulence. Increased leuO expression repressed aphA transcription, which resulted in downregulation of the ToxR regulon and attenuated CT and TCP production. The cyclo(Phe-Pro)-dependent induction of leuO expression was found to be dependent upon the virulence regulator ToxR. Cyclo(Phe-Pro) did not affect toxR transcription or ToxR protein levels but appeared to enhance the ToxR-dependent transcription of leuO. These results have identified leuO as a new component of the ToxR regulon and demonstrate for the first time that ToxR is capable of downregulating virulence gene expression in response to an environmental cue. The ToxR regulon has been a focus of cholera research for more than three decades. During this time, a model has emerged wherein ToxR functions to activate the expression of Vibrio cholerae virulence factors upon host entry. V. cholerae and other enteric bacteria produce cyclo(Phe-Pro), a cyclic dipeptide that we identified as an inhibitor of V. cholerae virulence factor production. This finding suggested that cyclo(Phe-Pro) was a negative effector of virulence factor production and represented a molecule that could potentially be exploited for therapeutic development. In this work, we investigated the mechanism by which cyclo(Phe-Pro) inhibited virulence factor production. We found that cyclo(Phe-Pro) signaled through ToxR to activate the expression of leuO, a new virulence regulator that functioned to repress virulence factor production. Our results have identified a new arm of the ToxR regulon and suggest that ToxR may play a broader role in pathogenesis than previously known.

Protein geranylgeranyltransferase of Saccharomyces cerevisiae is specific for Cys-Xaa-Xaa-Leu motif proteins and requires the CDC43 gene product but not the DPR1 gene product.

PubMed Central

Finegold, A A; Johnson, D I; Farnsworth, C C; Gelb, M H; Judd, S R; Glomset, J A; Tamanoi, F

1991-01-01

Protein prenylation occurs by modification of proteins with one of at least two isoprenoids, the farnesyl group and the geranylgeranyl group. Protein farnesyltransferases have been identified, but no such enzyme has been identified for geranylgeranylation. We report the identification of an activity in crude soluble yeast extracts that catalyzes the transfer of a geranylgeranyl moiety from geranylgeranyl pyrophosphate to proteins having the C-terminal sequence Cys-Ile-Ile-Leu or Cys-Val-Leu-Leu but not to a similar protein ending with Cys-Ile-Ile-Ser. This activity is dependent upon the CDC43/CAL1 gene, which is involved in budding and the control of cell polarity, but does not require the DPR1/RAM1 gene, which is known to be required for the farnesylation of Ras proteins. These results indicate that the protein geranylgeranyltransferase activity is distinct from the protein farnesyltransferase activity and that its specificity depends in part on the extreme C-terminal leucine in the protein to be prenylated. Images PMID:2034682

Future U.S. supply of Mo-99 production through fission based LEU/LEU technology.

PubMed

Welsh, James; Bigles, Carmen I; Valderrabano, Alejandro

Coquí RadioPharmaceuticals Corp. (Coquí) has the goal of establishing a medical isotope production facility for securing a continuous domestic supply of the radioisotope molybdenum-99 for U.S. citizens. Coquí will use an LEU/LEU proven and implemented open pool, light-water, 10 MW, reactor design. The facility is being designed with twin reactors for reliability an on-site hot lab chemical processing and a waste conditioning area and a possible generator producing radio-chemistry lab. Coquí identified a 25 acre site adjacent to an existing industrial park in northern central Florida. This land was gifted and transferred to Coquí by the University of Florida Foundation. We are in the process of developing licensing documents related to the facility. The construction permit application for submission to the U.S. Nuclear Regulatory Commission is currently being prepared. Submission is scheduled for mid to late 2015. Community reaction to the proposed development has been positive. We expect to create 220 permanent jobs and we have an anticipated to be operational by 2020.

Combined DNA, toxicological and heavy metal analyses provides an auditing toolkit to improve pharmacovigilance of traditional Chinese medicine (TCM)

NASA Astrophysics Data System (ADS)

Coghlan, Megan L.; Maker, Garth; Crighton, Elly; Haile, James; Murray, Dáithí C.; White, Nicole E.; Byard, Roger W.; Bellgard, Matthew I.; Mullaney, Ian; Trengove, Robert; Allcock, Richard J. N.; Nash, Christine; Hoban, Claire; Jarrett, Kevin; Edwards, Ross; Musgrave, Ian F.; Bunce, Michael

2015-12-01

Globally, there has been an increase in the use of herbal remedies including traditional Chinese medicine (TCM). There is a perception that products are natural, safe and effectively regulated, however, regulatory agencies are hampered by a lack of a toolkit to audit ingredient lists, adulterants and constituent active compounds. Here, for the first time, a multidisciplinary approach to assessing the molecular content of 26 TCMs is described. Next generation DNA sequencing is combined with toxicological and heavy metal screening by separation techniques and mass spectrometry (MS) to provide a comprehensive audit. Genetic analysis revealed that 50% of samples contained DNA of undeclared plant or animal taxa, including an endangered species of Panthera (snow leopard). In 50% of the TCMs, an undeclared pharmaceutical agent was detected including warfarin, dexamethasone, diclofenac, cyproheptadine and paracetamol. Mass spectrometry revealed heavy metals including arsenic, lead and cadmium, one with a level of arsenic >10 times the acceptable limit. The study showed 92% of the TCMs examined were found to have some form of contamination and/or substitution. This study demonstrates that a combination of molecular methodologies can provide an effective means by which to audit complementary and alternative medicines.

Combined DNA, toxicological and heavy metal analyses provides an auditing toolkit to improve pharmacovigilance of traditional Chinese medicine (TCM).

PubMed

Coghlan, Megan L; Maker, Garth; Crighton, Elly; Haile, James; Murray, Dáithí C; White, Nicole E; Byard, Roger W; Bellgard, Matthew I; Mullaney, Ian; Trengove, Robert; Allcock, Richard J N; Nash, Christine; Hoban, Claire; Jarrett, Kevin; Edwards, Ross; Musgrave, Ian F; Bunce, Michael

2015-12-10

Globally, there has been an increase in the use of herbal remedies including traditional Chinese medicine (TCM). There is a perception that products are natural, safe and effectively regulated, however, regulatory agencies are hampered by a lack of a toolkit to audit ingredient lists, adulterants and constituent active compounds. Here, for the first time, a multidisciplinary approach to assessing the molecular content of 26 TCMs is described. Next generation DNA sequencing is combined with toxicological and heavy metal screening by separation techniques and mass spectrometry (MS) to provide a comprehensive audit. Genetic analysis revealed that 50% of samples contained DNA of undeclared plant or animal taxa, including an endangered species of Panthera (snow leopard). In 50% of the TCMs, an undeclared pharmaceutical agent was detected including warfarin, dexamethasone, diclofenac, cyproheptadine and paracetamol. Mass spectrometry revealed heavy metals including arsenic, lead and cadmium, one with a level of arsenic >10 times the acceptable limit. The study showed 92% of the TCMs examined were found to have some form of contamination and/or substitution. This study demonstrates that a combination of molecular methodologies can provide an effective means by which to audit complementary and alternative medicines.

Combined DNA, toxicological and heavy metal analyses provides an auditing toolkit to improve pharmacovigilance of traditional Chinese medicine (TCM)

PubMed Central

Coghlan, Megan L.; Maker, Garth; Crighton, Elly; Haile, James; Murray, Dáithí C.; White, Nicole E.; Byard, Roger W.; Bellgard, Matthew I.; Mullaney, Ian; Trengove, Robert; Allcock, Richard J. N.; Nash, Christine; Hoban, Claire; Jarrett, Kevin; Edwards, Ross; Musgrave, Ian F.; Bunce, Michael

2015-01-01

Globally, there has been an increase in the use of herbal remedies including traditional Chinese medicine (TCM). There is a perception that products are natural, safe and effectively regulated, however, regulatory agencies are hampered by a lack of a toolkit to audit ingredient lists, adulterants and constituent active compounds. Here, for the first time, a multidisciplinary approach to assessing the molecular content of 26 TCMs is described. Next generation DNA sequencing is combined with toxicological and heavy metal screening by separation techniques and mass spectrometry (MS) to provide a comprehensive audit. Genetic analysis revealed that 50% of samples contained DNA of undeclared plant or animal taxa, including an endangered species of Panthera (snow leopard). In 50% of the TCMs, an undeclared pharmaceutical agent was detected including warfarin, dexamethasone, diclofenac, cyproheptadine and paracetamol. Mass spectrometry revealed heavy metals including arsenic, lead and cadmium, one with a level of arsenic >10 times the acceptable limit. The study showed 92% of the TCMs examined were found to have some form of contamination and/or substitution. This study demonstrates that a combination of molecular methodologies can provide an effective means by which to audit complementary and alternative medicines. PMID:26658160

High Leucine Diets Stimulate Cerebral Branched-Chain Amino Acid Degradation and Modify Serotonin and Ketone Body Concentrations in a Pig Model

PubMed Central

Wessels, Anna G.; Kluge, Holger; Hirche, Frank; Kiowski, Andreas; Schutkowski, Alexandra; Corrent, Etienne; Bartelt, Jörg; König, Bettina; Stangl, Gabriele I.

2016-01-01

In addition to its role as an essential protein component, leucine (Leu) displays several other metabolic functions such as activation of protein synthesis. This property makes it an interesting amino acid for the therapy of human muscle atrophy and for livestock production. However, Leu can stimulate its own degradation via the branched-chain keto acid dehydrogenase complex (BCKDH). To examine the response of several tissues to excessive Leu, pigs were fed diets containing two- (L2) and four-fold (L4) higher Leu contents than the recommended amount (control). We found that the L4 diet led to a pronounced increase in BCKDH activity in the brain (2.5-fold, P < 0.05), liver (1.8-fold, P < 0.05) and cardiac muscle (1.7-fold, P < 0.05), whereas we found no changes in enzyme activity in the pancreas, skeletal muscle, adipose tissue and intestinal mucosa. The L2 diet had only weak effects on BCKDH activity. Both high Leu diets reduced the concentrations of free valine and isoleucine in nearly all tissues. In the brain, high Leu diets modified the amount of tryptophan available: for serotonin synthesis. Compared to the controls, pigs treated with the high Leu diets consumed less food, showed increased plasma concentrations of 3-hydroxybutyrate and reduced levels of circulating serotonin. In conclusion, excessive Leu can stimulate BCKDH activity in several tissues, including the brain. Changes in cerebral tryptophan, along with the changes in amino acid-derived metabolites in the plasma may limit the use of high Leu diets to treat muscle atrophy or to increase muscle growth. PMID:26930301

Measurement of the 235U Induced Fission Gamma-ray Spectrum as an Active Non-destructive Assay of Fresh Nucleear Fuel

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sarnoski, Sarah E.; Fast, James E.; Fulsom, Bryan G.

2017-07-17

Non-destructive assay is a powerful tool the International Atomic Energy Agency (IAEA) employs to verify adherence to safeguards agreements. Current IAEA veri- cation techniques for fresh nuclear fuel include passive gamma-ray spectroscopy to determine fuel enrichment. This technique suers from self-shielding and lakes the percision to detect diversion of central fuel rods. The aim of this research is to develop a new, more capable non-destructive analysis technique using active neutron interroga- tion of fuel assemblies and determining the yields of short-lived ssion products from high-resolution gamma-ray spectroscopy using high-purity germanium (HPGe). This paper reports results from irradiation of a onemore » meter tall mock fresh fuel assembly with low enriched uranium (LEU) or depleted uranium (DU) rods using a down-scattered deuterium-tritium (D-T) neutron source. Both prompt and delayed gamma-ray spec- tra were collected as time-stamped list-mode data in a coax detector and without list mode data in a planar strip detector. No dierentiating signatures were observed in the prompt spectra in either detector; however, both detectors observed several short-lived ssion product signatures in LEU and not DU fuel, indicating that this technique has potential for determination of enrichment of fresh fuel assemblies. There were eight unique ssion products observed in the LEU spectra with the coax detector spectra, and three ssion products were observed in the LEU spectra with the strip detector.« less

Analysis of U.S. Food and Drug Administration food allergen recalls after implementation of the food allergen labeling and consumer protection act.

PubMed

Gendel, Steven M; Zhu, Jianmei

2013-11-01

To avoid potentially life-threatening reactions, food allergic consumers rely on information on food labels to help them avoid exposure to a food or ingredient that could trigger a reaction. To help consumers in the United States obtain the information that they need, the Food Allergen Labeling and Consumer Protection Act of 2004 defined a major food allergen as being one of eight foods or food groups and any ingredient that contains protein from one of these foods or food groups. A food that contains an undeclared major food allergen is misbranded under the U.S. Food, Drug, and Cosmetic Act and is subject to recall. Food allergen labeling problems are the most common cause of recalls for U.S. Food and Drug Administration (FDA)-regulated food products. To help understand why food allergen recalls continue to occur at a high rate, information on each food allergen recall that occurred in fiscal years 2007 through 2012 was obtained from the FDA recall database. This information was analyzed to identify the food, allergen, root cause, and mode of discovery for each food allergen recall. Bakery products were the most frequently recalled food type, and milk was the most frequently undeclared major food allergen. Use of the wrong package or label was the most frequent problem leading to food allergen recalls. These data are the first reported that indicate the importance of label and package controls as public health measures.

The influence of abrupt increases in seawater pCO2 on plankton productivity in the subtropical North Pacific Ocean

PubMed Central

Böttjer, Daniela; Letelier, Ricardo M.; Church, Matthew J.

2018-01-01

We conducted a series of experiments to examine short-term (2–5 days) effects of abrupt increases in the partial pressure of carbon dioxide (pCO2) in seawater on rates of primary and bacterial production at Station ALOHA (22°45’ N, 158° W) in the North Pacific Subtropical Gyre (NPSG). The majority of experiments (8 of 10 total) displayed no response in rates of primary production (measured by 14C-bicarbonate assimilation; 14C-PP) under elevated pCO2 (~1100 μatm) compared to ambient pCO2 (~387 μatm). In 2 of 10 experiments, rates of 14C-PP decreased significantly (~43%) under elevated pCO2 treatments relative to controls. Similarly, no significant differences between treatments were observed in 6 of 7 experiments where bacterial production was measured via incorporation of 3H-leucine (3H-Leu), while in 1 experiment, rates of 3H-Leu incorporation measured in the dark (3H-LeuDark) increased more than 2-fold under high pCO2 conditions. We also examined photoperiod-length, depth-dependent (0–125 m) responses in rates of 14C-PP and 3H-Leu incorporation to abrupt pCO2 increases (to ~750 μatm). In the majority of these depth-resolved experiments (4 of 5 total), rates of 14C-PP demonstrated no consistent response to elevated pCO2. In 2 of 5 depth-resolved experiments, rates of 3H-LeuDark incorporation were lower (10% to 15%) under elevated pCO2 compared to controls. Our results revealed that rates of 14C-PP and bacterial production in this persistently oligotrophic habitat generally demonstrated no or weak responses to abrupt changes in pCO2. We postulate that any effects caused by changes in pCO2 may be masked or outweighed by the role that nutrient availability and temperature play in controlling metabolism in this ecosystem. PMID:29694353

Development and characterization of novel 8-plex DiLeu isobaric labels for quantitative proteomics and peptidomics

PubMed Central

Frost, Dustin C.; Greer, Tyler; Xiang, Feng; Liang, Zhidan; Li, Lingjun

2015-01-01

Rationale Relative quantification of proteins via their enzymatically digested peptide products determines disease biomarker candidate lists in discovery studies. Isobaric label-based strategies using TMT and iTRAQ allow for up to 10 samples to be multiplexed in one experiment, but their expense limits their use. The demand for cost-effective tagging reagents capable of multiplexing many samples led us to develop an 8-plex version of our isobaric labeling reagent, DiLeu. Methods The original 4-plex DiLeu reagent was extended to an 8-plex set by coupling isotopic variants of dimethylated leucine to an alanine balance group designed to offset the increasing mass of the label’s reporter group. Tryptic peptides from a single protein digest, a protein mixture digest, and Saccharomyces cerevisiae lysate digest were labeled with 8-plex DiLeu and analyzed via nanoLC-MS2 on a Q-Exactive Orbitrap mass spectrometer. Characteristics of 8-plex DiLeu-labeled peptides, including quantitative accuracy and fragmentation, were examined. Results An 8-plex set of DiLeu reagents with 1 Da-spaced reporters was synthesized at a yield of 36%. The average cost to label eight 100 μg peptide samples was calculated to be approximately $15. Normalized collision energy tests on the Q-Exactive revealed that a higher-energy collisional dissociation value of 27 generated the optimum number of high-quality spectral matches. Relative quantification of DiLeu-labeled peptides yielded normalized median ratios accurate to within 12% of their expected values. Conclusions Cost-effective 8-plex DiLeu reagents can be synthesized and applied to relative peptide and protein quantification. These labels increase the multiplexing capacity of our previous 4-plex implementation without requiring high-resolution instrumentation to resolve reporter ion signals. PMID:25981542

Uranium Enrichment Safeguards

DOE Office of Scientific and Technical Information (OSTI.GOV)

Demuth, Scott F.; Trahan, Alexis Chanel

2017-06-26

DIV of facility layout, material flows, and other information provided in the DIQ. Material accountancy through an annual PIV and a number of interim inventory verifications, including UF6 cylinder identification and counting, NDA of cylinders, and DA on a sample collection of UF6. Application of C/S technologies utilizing seals and tamper-indicating devices (TIDs) on cylinders, containers, storage rooms, and IAEA instrumentation to provide continuity of knowledge between inspection. Verification of the absence of undeclared material and operations, especially HEU production, through SNRIs, LFUA of cascade halls, and environmental swipe sampling

Advanced image collection, information extraction, and change detection in support of NN-20 broad area search and analysis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Petrie, G.M.; Perry, E.M.; Kirkham, R.R.

1997-09-01

This report describes the work performed at the Pacific Northwest National Laboratory (PNNL) for the U.S. Department of Energy`s Office of Nonproliferation and National Security, Office of Research and Development (NN-20). The work supports the NN-20 Broad Area Search and Analysis, a program initiated by NN-20 to improve the detection and classification of undeclared weapons facilities. Ongoing PNNL research activities are described in three main components: image collection, information processing, and change analysis. The Multispectral Airborne Imaging System, which was developed to collect georeferenced imagery in the visible through infrared regions of the spectrum, and flown on a light aircraftmore » platform, will supply current land use conditions. The image information extraction software (dynamic clustering and end-member extraction) uses imagery, like the multispectral data collected by the PNNL multispectral system, to efficiently generate landcover information. The advanced change detection uses a priori (benchmark) information, current landcover conditions, and user-supplied rules to rank suspect areas by probable risk of undeclared facilities or proliferation activities. These components, both separately and combined, provide important tools for improving the detection of undeclared facilities.« less

Light Conditions Affect the Measurement of Oceanic Bacterial Production via Leucine Uptake

PubMed Central

Morán, Xosé Anxelu G.; Massana, Ramon; Gasol, Josep M.

2001-01-01

The effect of irradiance in the range of 400 to 700 nm or photosynthetically active radiation (PAR) on bacterial heterotrophic production estimated by the incorporation of 3H-leucine (referred to herein as Leu) was investigated in the northwestern Mediterranean Sea and in a coastal North Atlantic site, with Leu uptake rates ranging over 3 orders of magnitude. We performed in situ incubations under natural irradiance levels of Mediterranean samples taken from five depths around solar noon and compared them to incubations in the dark. In two of the three stations large differences were found between light and dark uptake rates for the surfacemost samples, with dark values being on average 133 and 109% higher than in situ ones. Data obtained in coastal North Atlantic waters confirmed that dark enclosure may increase Leu uptake rates more than threefold. To explain these differences, on-board experiments of Leu uptake versus irradiance were performed with Mediterranean samples from depths of 5 and 40 m. Incubations under a gradient of 12 to 1,731 μmol of photons m−2 s−1 evidenced a significant increase in incorporation rates with increasing PAR in most of the experiments, with dark-incubated samples departing from this pattern. These results were not attributed to inhibition of Leu uptake in the light but to enhanced bacterial response when transferred to dark conditions. The ratio of dark to light uptake rates increased as dissolved inorganic nitrogen concentrations decreased, suggesting that bacterial nutrient deficiency was overcome by some process occurring only in the dark bottles. PMID:11525969

Progress on RERTR activities in Argentina

DOE Office of Scientific and Technical Information (OSTI.GOV)

Balart, S.; Calzetta, O.; Cristini, P.

2008-07-15

Since last RERTR meeting, several tasks involving RERTR activities continued deploying in Argentina: through an agreement between CNEA and US-DoE final steps in the RA-6 reactor core conversion from HEU to LEU are taking place; by means of a return campaign of 42 US origin SNF in the frame of the US-SNF FRR program; an effective minimization of HEU inventory is close to be accomplished; development of a LEU dispersed U-Mo fuel prototype, to be irradiated in a high flux reactor in the frame of the ARG/4/092 IAEA's Technical Cooperation project is progressing; very high density monolithic U-Mo miniplates andmore » plates using MEU and LEU fuel with Zry-4 cladding were developed to be irradiated as a part of the RERTR program irradiation experiment; atomistic modeling prediction (BFS techniques and first principles) enabled to find some trends on the interaction phases; diffusion couples tests under X-ray synchrotron analysis allowed the characterization of several phases involving U-Mo(-Zr) / Al(-Si); finally CNEA continued spreading high quality LEU technology for fission RI production by means of agreements with different producers interested on HEU-LEU conversion. (author)« less

Preparation of antioxidative corn protein hydrolysates, purification and evaluation of three novel corn antioxidant peptides.

PubMed

Jin, Du-Xin; Liu, Xiao-Lan; Zheng, Xi-Qun; Wang, Xiao-Jie; He, Jun-Fang

2016-08-01

Corn gluten meal is a major co-product of corn wet milling. Corn gluten meal was hydrolyzed with Alcalase, Flavourzyme, Alcalase+Flavourzyme and Flavourzyme+Alcalase. At the substrate concentration of 10%, corn protein hydrolysate catalyzed by Alcalase had a degree of hydrolysis of 17.83%, which was higher than that by Flavourzyme (3.65%). The hydrolysate catalyzed by Alcalase+Flavourzyme exhibited better antioxidant activities and was further purified. Three novel antioxidant peptides were purified by a series of chromatographic techniques. Sequences of the three peptides were identified as Cys-Ser-Gln-Ala-Pro-Leu-Ala, Tyr-Pro-Lys-Leu-Ala-Pro-Asn-Glu and Tyr-Pro-Gln-Leu-Leu-Pro-Asn-Glu, respectively. Among the three peptides, Cys-Ser-Gln-Ala-Pro-Leu-Ala exhibited good reducing power and excellent scavenging capacities for DPPH radical and superoxide anion radical, with IC50 values of 0.116 and 0.39mg/ml, respectively. The results from our study indicate antioxidant potency of corn protein hydrolysates and peptides separated from corn gluten meal and can provide basic understanding for the application of corn protein hydrolysates as natural antioxidants. Copyright © 2016 Elsevier Ltd. All rights reserved.

Isolation and characterization of awamori yeast mutants with L-leucine accumulation that overproduce isoamyl alcohol.

PubMed

Takagi, Hiroshi; Hashida, Keisuke; Watanabe, Daisuke; Nasuno, Ryo; Ohashi, Masataka; Iha, Tomoya; Nezuo, Maiko; Tsukahara, Masatoshi

2015-02-01

Awamori shochu is a traditional distilled alcoholic beverage made from steamed rice in Okinawa, Japan. Although it has a unique aroma that is distinguishable from that of other types of shochu, no studies have been reported on the breeding of awamori yeasts. In yeast, isoamyl alcohol (i-AmOH), known as the key flavor of bread, is mainly produced from α-ketoisocaproate in the pathway of L-leucine biosynthesis, which is regulated by end-product inhibition of α-isopropylmalate synthase (IPMS). Here, we isolated mutants resistant to the L-leucine analog 5,5,5-trifluoro-DL-leucine (TFL) derived from diploid awamori yeast of Saccharomyces cerevisiae. Some of the mutants accumulated a greater amount of intracellular L-leucine, and among them, one mutant overproduced i-AmOH in awamori brewing. This mutant carried an allele of the LEU4 gene encoding the Ser542Phe/Ala551Val variant IPMS, which is less sensitive to feedback inhibition by L-leucine. Interestingly, we found that either of the constituent mutations (LEU4(S542F) and LEU4(A551V)) resulted in the TFL tolerance of yeast cells and desensitization to L-leucine feedback inhibition of IPMS, leading to intracellular L-leucine accumulation. Homology modeling also suggested that L-leucine binding was drastically inhibited in the Ser542Phe, Ala551Val, and Ser542Phe/Ala551Val variants due to steric hindrance in the cavity of IPMS. As we expected, awamori yeast cells expressing LEU4(S542F), LEU4(A551V), and LEU4(S542F/A551V) showed a prominent increase in extracellular i-AmOH production, compared with that of cells carrying the vector only. The approach described here could be a practical method for the breeding of novel awamori yeasts to expand the diversity of awamori taste and flavor. Copyright © 2014 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

Neutronic and thermal-hydraulic analysis of fission molybdenum-99 production at Tehran Research Reactor using LEU plate targets.

PubMed

Abedi, Ebrahim; Ebrahimkhani, Marzieh; Davari, Amin; Mirvakili, Seyed Mohammad; Tabasi, Mohsen; Maragheh, Mohammad Ghannadi

2016-12-01

Efficient and safe production of molybdenum-99 ( 99 Mo) radiopharmaceutical at Tehran Research Reactor (TRR) via fission of LEU targets is studied. Neutronic calculations are performed to evaluate produced 99 Mo activity, core neutronic safety parameters and also the power deposition values in target plates during a 7 days irradiation interval. Thermal-hydraulic analysis has been also carried out to obtain thermal behavior of these plates. Using Thermal-hydraulic analysis, it can be concluded that the safety parameters are satisfied in the current study. Consequently, the present neutronic and thermal-hydraulic calculations show efficient 99 Mo production is accessible at significant activity values in TRR current core configuration. Copyright © 2016 Elsevier Ltd. All rights reserved.

Halal authenticity issues in meat and meat products.

PubMed

Nakyinsige, Khadijah; Man, Yaakob Bin Che; Sazili, Awis Qurni

2012-07-01

In the recent years, Muslims have become increasingly concerned about the meat they eat. Proper product description is very crucial for consumers to make informed choices and to ensure fair trade, particularly in the ever growing halal food market. Globally, Muslim consumers are concerned about a number of issues concerning meat and meat products such as pork substitution, undeclared blood plasma, use of prohibited ingredients, pork intestine casings and non-halal methods of slaughter. Analytical techniques which are appropriate and specific have been developed to deal with particular issues. The most suitable technique for any particular sample is often determined by the nature of the sample itself. This paper sets out to identify what makes meat halal, highlight the halal authenticity issues that occur in meat and meat products and provide an overview of the possible analytical methods for halal authentication of meat and meat products. Copyright © 2012 Elsevier Ltd. All rights reserved.

Quorum-sensing inhibitory compounds from extremophilic microorganisms isolated from a hypersaline cyanobacterial mat.

PubMed

Abed, Raeid M M; Dobretsov, Sergey; Al-Fori, Marwan; Gunasekera, Sarath P; Sudesh, Kumar; Paul, Valerie J

2013-07-01

In this study, extremely halophilic and moderately thermophilic microorganisms from a hypersaline microbial mat were screened for their ability to produce antibacterial, antidiatom, antialgal, and quorum-sensing (QS) inhibitory compounds. Five bacterial strains belonging to the genera Marinobacter and Halomonas and one archaeal strain belonging to the genus Haloterrigena were isolated from a microbial mat. The strains were able to grow at a maximum salinity of 22-25 % and a maximum temperature of 45-60 °C. Hexanes, dichloromethane, and butanol extracts from the strains inhibited the growth of at least one out of nine human pathogens. Only butanol extracts of supernatants of Halomonas sp. SK-1 inhibited growth of the microalga Dunaliella salina. Most extracts from isolates inhibited QS of the acyl homoserine lactone producer and reporter Chromobacterium violaceum CV017. Purification of QS inhibitory dichloromethane extracts of Marinobacter sp. SK-3 resulted in isolation of four related diketopiperazines (DKPs): cyclo(L-Pro-L-Phe), cyclo(L-Pro-L-Leu), cyclo(L-Pro-L-isoLeu), and cyclo(L-Pro-D-Phe). QS inhibitory properties of these DKPs were tested using C. violaceum CV017 and Escherichia coli-based QS reporters (pSB401 and pSB1075) deficient in AHL production. Cyclo(L-Pro-L-Phe) and cyclo(L-Pro-L-isoLeu) inhibited QS-dependent production of violacein by C. violaceum CV017. Cyclo(L-Pro-L-Phe), cyclo(L-Pro-L-Leu), and cyclo(L-Pro-L-isoLeu) reduced QS-dependent luminescence of the reporter E. coli pSB401 induced by 3-oxo-C6-HSL. Our study demonstrated the ability of halophilic and moderately thermophilic strains from a hypersaline microbial mat to produce biotechnologically relevant compounds that could be used as antifouling agents.

The Case for the Application of Worldwide Marine Radioactivity Studies In the Search for Undeclared Facilities and Activities

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mark Schanfein

2013-06-01

Undeclared nuclear facilities unequivocally remain the most difficult safeguards challenge facing the International Atomic Energy Agency (IAEA). Recent cases of undeclared facilities revealed in Iran and Syria, which are NPT signatory States, show both the difficulty and the seriousness of this threat to nonproliferation. In the case of undeclared nuclear facilities, the most effective deterrent against proliferation is the application of Wide-Area Environmental Sampling (WAES); however, WAES is currently cost-prohibitive. As with any threat, the most effective countering strategy is a multifaceted approach. Some of the approaches applied by the IAEA include: open source analysis, satellite imagery, on-site environmental sampling,more » complementary access under the Additional Protocol (where in force), traditional safeguards inspections, and information provided by member States. These approaches, naturally, are focused on specific States. Are there other opportunities not currently within the IAEA purview to assess States that may provide another opportunity to detect clandestine facilities? In this paper, the author will make the case that the IAEA Department of Safeguards should explore the area of worldwide marine radioactivity studies as one possible opportunity. One such study was released by the IAEA Marine Environment Laboratory in January 2005. This technical document focused on 90Sr, 137Cs, and 239/240Pu. It is clearly a challenging area because of the many sources of anthropogenic radionuclides in the world’s oceans and seas including: nuclear weapons testing, reprocessing, accidents, waste dumping, and industrial and medical radioisotopes, whose distributions change based on oceanographic, geochemical, and biological processes, and their sources. It is additionally challenging where multiple States share oceans, seas, and rivers. But with the application of modern science, historical sampling to establish baselines, and a focus on the most relevant radionuclides, the potential is there to support this challenging IAEA safeguards mission.« less

Minor isotope safeguards techniques (MIST): Analysis and visualization of gas centrifuge enrichment plant process data using the MSTAR model

NASA Astrophysics Data System (ADS)

Shephard, Adam M.; Thomas, Benjamin R.; Coble, Jamie B.; Wood, Houston G.

2018-05-01

This paper presents a development related to the use of minor isotope safeguards techniques (MIST) and the MSTAR cascade model as it relates to the application of international nuclear safeguards at gas centrifuge enrichment plants (GCEPs). The product of this paper is a derivation of the universal and dimensionless MSTAR cascade model. The new model can be used to calculate the minor uranium isotope concentrations in GCEP product and tails streams or to analyze, visualize, and interpret GCEP process data as part of MIST. Applications of the new model include the detection of undeclared feed and withdrawal streams at GCEPs when used in conjunction with UF6 sampling and/or other isotopic measurement techniques.

15 CFR 716.7 - Samples.

Code of Federal Regulations, 2010 CFR

2010-01-01

... AND SECURITY, DEPARTMENT OF COMMERCE CHEMICAL WEAPONS CONVENTION REGULATIONS INITIAL AND ROUTINE... will be restricted to verifying the absence of undeclared scheduled chemicals, unless otherwise agreed...

15 CFR 716.7 - Samples.

Code of Federal Regulations, 2011 CFR

2011-01-01

... AND SECURITY, DEPARTMENT OF COMMERCE CHEMICAL WEAPONS CONVENTION REGULATIONS INITIAL AND ROUTINE... will be restricted to verifying the absence of undeclared scheduled chemicals, unless otherwise agreed...

Collision-induced dissociation of diazirine-labeled peptide ions. Evidence for Brønsted-acid assisted elimination of nitrogen.

PubMed

Marek, Aleš; Tureček, František

2014-05-01

Gas-phase dissociations were investigated for several peptide ions containing the Gly-Leu* N-terminal motif where Leu* was a modified norleucine residue containing the photolabile diazirine ring. Collisional activation of gas-phase peptide cations resulted in facile N₂ elimination that competed with backbone dissociations. A free lysine ammonium group can act as a Brønsted acid to facilitate N₂ elimination. This dissociation was accompanied by insertion of a lysine proton in the side chain of the photoleucine residue, as established by deuterium labeling and gas-phase sequencing of the products. Electron structure calculations were used to provide structures and energies of reactants, intermediates, and transition states for Gly-Leu*-Gly-Gly-Lys amide ions that were combined with RRKM calculations of unimolecular rate constants. The calculations indicated that Brønsted acid-catalyzed eliminations were kinetically preferred over direct loss of N₂ from the diazirine ring. Mechanisms are proposed to explain the proton-initiated reactions and discuss the reaction products. The non-catalyzed diazirine ring cleavage and N₂ loss is proposed as a thermometer dissociation for peptide ion dissociations.

Purification and Characterization of Peptides Inhibiting MMP-1 Activity with C Terminate of Gly-Leu from Simulated Gastrointestinal Digestion Hydrolysates of Tilapia (Oreochromis niloticus) Skin Gelatin.

PubMed

Liping, Sun; Qiuming, Liu; Jian, Fan; Xiao, Li; Yongliang, Zhuang

2018-01-24

Tilapia skin gelatin hydrolysates (TSGHs) were prepared by simulated gastrointestinal digestion and separated by gel filtration and semi-preparative reversed-phase high-performance liquid chromatography. The anti-photoaging effects were evaluated using an ultraviolet radiation B (UVB)-induced mouse embryonic fibroblast (MEF) photoaging model in vitro. Three fractions from TSGHs with high inhibitory intercellular matrix metalloproteinase-1 (MMP-1) activities and reactive oxygen species (ROS) production were obtained. Three key peptides, GYTGL, LGATGL, and VLGL, were identified, and their C terminate was Gly-Leu. Three peptides were synthesized and exhibited a significant inhibition of intercellular MMP-1 activity and ROS production. Furthermore, three peptides inhibiting MMP-1 activities were evaluated through their docking of S 1 ' and S 3 ' active pockets of MMP-1. Hydrogen bonds and C terminate Gly-Leu played important roles. Finally, the protective effects of three peptides on intercellular collagen in UVB-induced MEFs were compared. Our results indicated that tilapia gelatin peptides exhibited potential activities to prevent and regulate photoaging.

ANL progress on the cooperation with CNEA for the Mo-99 production : base-side digestion process.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gelis, A. V.; Quigley, K. J.; Aase, S. B.

2004-01-01

Conversion from high-enriched uranium (HEU) to low-enriched uranium (LEU) targets for the Mo-99 production requires certain modifications of the target design, the digestion and the purification processes. ANL is assisting the Argentine Comision Nacional de Energia Atomica (CNEA) to overcome all the concerns caused by the conversion to LEU foil targets. A new digester with stirring system has been successfully applied for the digestion of the low burn-up U foil targets in KMnO4 alkaline media. In this paper, we report the progress on the development of the digestion procedure with stirring focusing on the minimization of the liquid radioactive waste.

The lysosomotropic drug LeuLeu-OMe induces lysosome disruption and autophagy-independent cell death in Trypanosoma brucei

PubMed Central

Koh, Hazel X.; Aye, Htay M.; Tan, Kevin S. W.; He, Cynthia Y.

2015-01-01

Background: Trypanosoma brucei is a blood-borne, protozoan parasite that causes African sleeping sickness in humans and nagana in animals. The current chemotherapy relies on only a handful of drugs that display undesirable toxicity, poor efficacy and drug-resistance. In this study, we explored the use of lysosomotropic drugs to induce bloodstream form T. brucei cell death via lysosome destabilization. Methods: We measured drug concentrations that inhibit cell proliferation by 50% (IC_{50) for several compounds, chosen based on their lysosomotropic effects previously reported in Plasmodium falciparum. The lysosomal effects and cell death induced by L-leucyl-L-leucyl methyl ester (LeuLeu-OMe) were further analyzed by flow cytometry and immunofluorescence analyses of different lysosomal markers. The effect of autophagy in LeuLeu-OMe-induced lysosome destabilization and cytotoxicity was also investigated in control and autophagy-deficient cells. Results: LeuLeu-OMe was selected for detailed analyses due to its strong inhibitory profile against T. brucei with minimal toxicity to human cell lines in vitro. Time-dependent immunofluorescence studies confirmed an effect of LeuLeu-OMe on the lysosome. LeuLeu-OMe-induced cytotoxicity was also found to be dependent on the acidic pH of the lysosome. Although an increase in autophagosomes was observed upon LeuLeu-OMe treatment, autophagy was not required for the cell death induced by LeuLeu-OMe. Necrosis appeared to be the main cause of cell death upon LeuLeu-OMe treatment. Conclusions: LeuLeu-OMe is a lysosomotropic agent capable of destabilizing lysosomes and causing necrotic cell death in bloodstream form of T. brucei. PMID:28357304}

Diploid yeast cells yield homozygous spontaneous mutations

NASA Technical Reports Server (NTRS)

Esposito, M. S.; Bruschi, C. V.; Brushi, C. V. (Principal Investigator)

1993-01-01

A leucine-requiring hybrid of Saccharomyces cerevisiae, homoallelic at the LEU1 locus (leu1-12/leu1-12) and heterozygous for three chromosome-VII genetic markers distal to the LEU1 locus, was employed to inquire: (1) whether spontaneous gene mutation and mitotic segregation of heterozygous markers occur in positive nonrandom association and (2) whether homozygous LEU1/LEU1 mutant diploids are generated. The results demonstrate that gene mutation of leu1-12 to LEU1 and mitotic segregation of heterozygous chromosome-VII markers occur in strong positive nonrandom association, suggesting that the stimulatory DNA lesion is both mutagenic and recombinogenic. In addition, genetic analysis of diploid Leu+ revertants revealed that approximately 3% of mutations of leu1-12 to LEU1 result in LEU1/LEU1 homozygotes. Red-white sectored Leu+ colonies exhibit genotypes that implicate post-replicational chromatid breakage and exchange near the site of leu1-12 reversion, chromosome loss, and subsequent restitution of diploidy, in the sequence of events leading to mutational homozygosis. By analogy, diploid cell populations can yield variants homozygous for novel recessive gene mutations at biologically significant rates. Mutational homozygosis may be relevant to both carcinogenesis and the evolution of asexual diploid organisms.

Status and progress of the RERTR program in the year 2003.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Travelli, A.; Nuclear Engineering Division

2003-01-01

One of the most important events affecting the RERTR program during the past year was the decision by the U.S. Department of Energy to request the U.S. Congress to significantly increase RERTR program funding. This decision was prompted, at least in part, by the terrible events of September 11, 2001, and by a high-level U.S./Russian Joint Expert Group recommendation to immediately accelerate RERTR program activities in both countries, with the goal of converting all the world's research reactors to low-enriched fuel at the earliest possible time, and including both Soviet-designed and United States-designed research reactors. The U.S. Congress is expectedmore » to approve this request very soon, and the RERTR program has prepared itself well for the intense activities that the 'Accelerated RERTR Program' will require. Promising results have been obtained in the development of a fabrication process for monolithic LEU U-Mo fuel. Most existing and future research reactors could be converted to LEU with this fuel, which has a uranium density between 15.4 and 16.4 g/cm{sup 3} and yielded promising irradiation results in 2002. The most promising method hinges on producing the monolithic meat by cold-rolling a thin ingot produced by casting. The aluminum clad and the meat are bonded by friction stir welding and the cladding surface is finished by a light cold roll. This method can be applied to the production of miniplates and appears to be extendable to the production of full-size plates, possibly with intermediate anneals. Other methods planned for investigation include high temperature bonding and hot isostatic pressing. The progress achieved within the Russian RERTR program, both for the traditional tube-type elements and for the new 'universal' LEU U-Mo pin-type elements, promises to enable soon the conversion of many Russian-designed research and test reactors. Irradiation testing of both fuel types with LEU U-Mo dispersion fuels has begun. Detailed studies are in progress to define the feasibility of converting each Russian-designed research and test reactor to either fuel type. The plan for the Accelerated RERTR Program is structured to achieve LEU conversion of all HEU research reactors supplied by the United States and Russia during the next nine years. This effort will address, in addition to the fuel development and qualification, the analyses and performance/economic/safety evaluations needed to implement the conversions. In combination with this over-arching goal, the RERTR program plans to achieve at the earliest possible date qualification of LEU U-Mo dispersion fuels with uranium densities of 6 g/cm{sup 3} and 7 g/cm{sup 3}. Reactors currently using or planning to use LEU silicide fuel will rely on this fuel after termination of the FRRSNFA program, because it is acceptable to COGEMA for reprocessing. Qualification of LEU U-Mo dispersion fuels has suffered some unavoidable delays but, to accelerate it as much as possible, the RERTR program, the French CEA, and the Australian ANSTO have agreed to jointly pursue a two-element qualification test of LEU U-Mo dispersion fuel with uranium density of 7.0 g/cm{sup 3} to be performed in the Osiris reactor during 2004. The RERTR program also intends to eliminate all obstacles to the utilization of LEU in targets for isotope production, so that this important function can be performed without the need for weapons-grade materials. All of us, working together as we have for many years, can ensure that all these goals will be achieved. By promoting the efficiency and safety of research reactors while eliminating the traffic in weapons-grade uranium, we can prevent the possibility that some of this material might fall in the wrong hands. Few causes can be more deserving of our joint efforts.« less

Detection of Met-enkephalin and Leu-enkephalin in the posterior pituitary of the holostean fish, Amia calva.

PubMed

Dores, R M; McDonald, L K; Crim, J W

1989-01-01

Immunohistochemical analysis of the pituitary of the holostean fish, Amia calva, indicated that enkephalin-related immunoreactivity was restricted to the pars nervosa, and was not detected in other regions of the pituitary. Fractionation of acid extracts of posterior pituitaries by reverse phase HPLC followed by RIA analysis indicated the presence of immunoreactive Met-enkephalin and Leu-enkephalin. No immunoreactive forms were detected with RIAs specific for either Met-enkephalin-RF or Met-enkephalin-RGL. The molar ratio of Met- to Leu-enkephalin in this terminal field was 3:1 (n = 4). HPLC fractions were also digested with trypsin and carboxypeptidase B to test for C-terminally extended forms of Met-enkephalin. A novel modified form of Met-enkephalin was detected. Extracts of the posterior pituitary, forebrain, midbrain, hypothalamus and hindbrain were screened with RIAs specific for the Pro-dynorphin end products, alpha-neo-endorphin, dynorphin A(1-17), dynorphin A(1-8) and dynorphin B(1-13). The results of these analyses were negative. Collectively, these data suggest that a Pro-enkephalin-like molecule is present in holostean fish. The holostean enkephalin precursor contains at least Met-enkephalin and Leu-enkephalin. However, Pro-dynorphin-related end products with antigenic determinants similar to mammalian dynorphin A(1-17), dynorphin A(1-8), dynorphin B(1-13) and alpha-neo-endorphin could not be detected in the brain or pituitary of this species.

DIissolution of low enriched uranium from the experimental breeder reactor-II fuel stored at the Idaho National Laboratory

DOE Office of Scientific and Technical Information (OSTI.GOV)

Daniel, G.; Rudisill, T.; Almond, P.

The Idaho National Laboratory (INL) is actively engaged in the development of electrochemical processing technology for the treatment of fast reactor fuels using irradiated fuel from the Experimental Breeder Reactor-II (EBR-II) as the primary test material. The research and development (R&D) activities generate a low enriched uranium (LEU) metal product from the electrorefining of the EBR-II fuel and the subsequent consolidation and removal of chloride salts by the cathode processor. The LEU metal ingots from past R&D activities are currently stored at INL awaiting disposition. One potential disposition pathway is the shipment of the ingots to the Savannah River Sitemore » (SRS) for dissolution in H-Canyon. Carbon steel cans containing the LEU metal would be loaded into reusable charging bundles in the H-Canyon Crane Maintenance Area and charged to the 6.4D or 6.1D dissolver. The LEU dissolution would be accomplished as the final charge in a dissolver batch (following the dissolution of multiple charges of spent nuclear fuel (SNF)). The solution would then be purified and the 235U enrichment downblended to allow use of the U in commercial reactor fuel. To support this potential disposition path, the Savannah River National Laboratory (SRNL) developed a dissolution flowsheet for the LEU using samples of the material received from INL.« less

The alyteserins: two families of antimicrobial peptides from the skin secretions of the midwife toad Alytes obstetricans (Alytidae).

PubMed

Conlon, J Michael; Demandt, Anni; Nielsen, Per F; Leprince, Jérôme; Vaudry, Hubert; Woodhams, Douglas C

2009-06-01

Two families of structurally related C-terminally alpha-amidated antimicrobial peptides have been identified in norepinephrine-stimulated skin secretions of the midwife toad Alytes obstetricans (Alytidae). The alyteserin-1 peptides (Gly-Leu-Lys-(Asp/Glu)-Ile-Phe-Lys-Ala-Gly-Leu-Gly-Ser-Leu-Val-Lys-(Gly/Asn)-Ile-Ala-Ala-His-Val-Ala-(Asn/Ser).NH(2)) show limited structural similarity to the ascaphins from the skins of frogs of the family Leiopelmatidae. Alyteserin-2a (Ile-Leu-Gly-Lys-Leu-Leu-Ser-Thr-Ala-Ala-Gly-Leu-Leu-Ser-Asn-Leu.NH(2)) and alyteserin-2b and -2c (Ile-Leu-Gly-Ala-Ile-Leu-Pro-Leu-Val-Ser-Gly-Leu-Leu-Ser-(Asn/Ser)-Lys-Leu x NH(2)) show limited sequence identity with bombinin H6, present in the skins of frogs of the family Bombinatoridae. The alyteserin-1 peptides show selective growth inhibitory activity against the Gram-negative bacteria Escherichia coli (MIC=25 microM) whereas alyteserin-2a is more potent against the Gram-positive bacteria Staphylococcus aureus (MIC=50 microM). The hemolytic activity against human erythrocytes of all peptides tested is relatively weak (LC(50)>100 microM). The data demonstrate that the frogs belonging to the family Alytidae are among those producing dermal antimicrobial peptides that may represent a component of the animal's system of innate immunity.

Species identification and quantification in meat and meat products using droplet digital PCR (ddPCR).

PubMed

Floren, C; Wiedemann, I; Brenig, B; Schütz, E; Beck, J

2015-04-15

Species fraud and product mislabelling in processed food, albeit not being a direct health issue, often results in consumer distrust. Therefore methods for quantification of undeclared species are needed. Targeting mitochondrial DNA, e.g. CYTB gene, for species quantification is unsuitable, due to a fivefold inter-tissue variation in mtDNA content per cell resulting in either an under- (-70%) or overestimation (+160%) of species DNA contents. Here, we describe a reliable two-step droplet digital PCR (ddPCR) assay targeting the nuclear F2 gene for precise quantification of cattle, horse, and pig in processed meat products. The ddPCR assay is advantageous over qPCR showing a limit of quantification (LOQ) and detection (LOD) in different meat products of 0.01% and 0.001%, respectively. The specificity was verified in 14 different species. Hence, determining F2 in food by ddPCR can be recommended for quality assurance and control in production systems. Copyright © 2014 The Authors. Published by Elsevier Ltd.. All rights reserved.

Formation of specific amino acid sequences during carbodiimide-mediated condensation of amino acids in aqueous solution, and computer-simulated sequence generation

NASA Astrophysics Data System (ADS)

Hartmann, Jürgen; Nawroth, Thomas; Dose, Klaus

1984-12-01

Carbodiimide-mediated peptide synthesis in aqueous solution has been studied with respect to self-ordering of amino acids. The copolymerisation of amino acids in the presence of glutamic acid or pyroglutamic acid leads to short pyroglutamyl peptides. Without pyroglutamic acid the formation of higher polymers is favoured. The interactions of the amino acids and the peptides, however, are very complex. Therefore, the experimental results are rather difficult to explain. Some of the experimental results, however, can be explained with the aid of computer simulation programs. Regarding only the tripeptide fraction the copolymerisation of pyroGlu, Ala and Leu, as well as the simulated copolymerisation lead to pyroGlu-Ala-Leu as the main reaction product. The amino acid composition of the insoluble peptides formed during the copolymerisation of Ser, Gly, Ala, Val, Phe, Leu and Ile corresponds in part to the computer-simulated copolymerisation data.

Hypermutation in derepressed operons of Escherichia coli K12

PubMed Central

Wright, Barbara E.; Longacre, Angelika; Reimers, Jacqueline M.

1999-01-01

This article presents evidence that starvation for leucine in an Escherichia coli auxotroph triggers metabolic activities that specifically target the leu operon for derepression, increased rates of transcription, and mutation. Derepression of the leu operon was a prerequisite for its activation by the signal nucleotide, guanosine tetraphosphate, which accumulates in response to nutritional stress (the stringent response). A quantitative correlation was established between leuB mRNA abundance and leuB− reversion rates. To further demonstrate that derepression increased mutation rates, the chromosomal leu operon was placed under the control of the inducible tac promoter. When the leu operon was induced by isopropyl-d-thiogalactoside, both leuB mRNA abundance and leuB− reversion rates increased. These investigations suggest that guanosine tetraphosphate may contribute as much as attenuation in regulating leu operon expression and that higher rates of mutation are specifically associated with the derepressed leu operon. PMID:10220423

Nucleotide sequencing analysis of a LEU gene of Candida maltosa which complements leuB mutation of Escherichia coli and leu2 mutation of Saccharomyces cerevisiae.

PubMed

Takagi, M; Kobayashi, N; Sugimoto, M; Fujii, T; Watari, J; Yano, K

1987-01-01

The expression of a LEU gene from Candida maltosa (designated as C-LEU2) isolated previously (Kawamura et al. 1983) was shown to be regulated, when transferred into Saccharomyces cerevisiae, by leucine and threonine in the medium, as in the case of LEU2 gene of S. cerevisiae. The coding region together with the regulatory region was subcloned and the nucleotide sequence was determined. When the sequence of the coding region was compared with that of LEU2, the homology was 72% for base pairs and 76% for deduced amino acids. Comparison of the regulatory region of C-LEU2 with those of LEU1 and LEU2 suggested a few short consensus sequences which are involved in regulation of gene expression by leucine and threonine in the medium.

Phenolic profiles of raw apricots, pumpkins, and their purees in the evaluation of apricot nectar and jam authenticity.

PubMed

Dragovic-Uzelac, Verica; Delonga, Karmela; Levaj, Branka; Djakovic, Senka; Pospisil, Jasna

2005-06-15

The possibility of proving the undeclared addition of pumpkin puree in apricot nectars and jams has been investigated by using the phenol compound fingerprint and sensory evaluation. The cheaper pumpkin admixtures in apricot nectars and jams could not be detected by the sensory evaluation, particularly if present in quantities of <15%. The lower admixtures of pumpkin puree in apricot nectars and jams could be detected by the presence of syringic acid, a phenolic compound characteristic of the investigated pumpkins (Cucurbita pepo cv. Gleisdorff and Table Gold, Cucurbita maxima cv. Turkinja, and Cucurbita moschata cv. Argenta). Syringic acid was isolated from pumpkin puree and determined by using HPLC with diode array detection. By using the phenolic profile, undeclared pumpkin admixture (> or =5%) in the apricot nectars and jams could be proven.

Toxicity of leucine-containing peptides in Escherichia coli caused by circumvention of leucine transport regulation.

PubMed Central

Tavori, H; Kimmel, Y; Barak, Z

1981-01-01

A variety of leucine-containing peptides (LCP), Phe-Leu, Gly-Leu, Pro-Leu, Ala-Leu, Ala-Leu-Lys, Leu-Phe-Ala, Leu-Leu-Leu, and Leu-Gly-Gly, inhibited the growth of a prototrophic strain of Escherichia coli K-12 at concentrations between 0.05 and 0.28 mM. Toxicity requires normal uptake of peptides. When peptide transport was impaired by mutations, strains became resistant to the respective LCP. Inhibition of growth occurred immediately after the addition of LCP, and was relieved when 0.4 mM isoleucine was added. The presence of Gly-Leu in the medium correlated with the inhibition of growth, and the bacteria began to grow at the normal rate 70 min after Gly-Leu became undetectable. Disappearance of the peptide corresponded with the appearance of free leucine and glycine in the medium. The concentration of leucine inside the LCP-treated bacteria was higher than that in the leucine-treated and the control cultures. We suggest that entry of LCP into the cells via peptide transport systems circumvents the regulation of leucine transport, thereby causing abnormality high concentrations of leucine inside the cells. This accumulation of leucine interferes with the biosynthesis of isoleucine and inhibits the growth of the bacteria. Images PMID:7012134

Circulating and in situ lymphocyte subsets and Langerhans cells in patients with compositae oleoresin dermatitis and increased ultraviolet A sensitivity during treatment with azathioprine

DOE Office of Scientific and Technical Information (OSTI.GOV)

Baadsgaard, O.

1986-04-01

Circulating and in situ lymphocyte subsets and Langerhans cells in four patients with compositae oleoresin dermatitis and increased ultraviolet A sensitivity before and during treatment with azathioprine were estimated. It was found that the number of Leu 6+ Langerhans cells decreased during therapy. This decrease was accompanied by a reduction in the number of Leu 2a+, Leu 3a+, Leu 4+, DR+, and Leu M2+ cells in the blood and a reduction in the number of Leu 2a+, Leu 3a+, Leu 4+, and DR+ cells in the skin. Concomitantly with the changes in the number of immunocompetent cells, the eczema cleared.

The Leu72Met polymorphism of the GHRL gene prevents the development of diabetic nephropathy in Chinese patients with type 2 diabetes mellitus.

PubMed

Zhuang, Langen; Li, Ming; Yu, Changhua; Li, Can; Zhao, Mingming; Lu, Ming; Zheng, Taishan; Zhang, Rong; Zhao, Weijing; Bao, Yuqian; Xiang, Kunsan; Jia, Weiping; Wang, Niansong; Liu, Limei

2014-02-01

The preproghrelin (GHRL) Leu72Met polymorphism (rs 696217) is associated with obesity, reduced glucose-induced insulin secretion in healthy or diabetic subjects, and reduced serum creatinine (Scr) levels in type 2 diabetes. We evaluated the association of the Leu72Met polymorphism with measures of insulin sensitivity in non-diabetic control individuals and type 2 diabetics, and whether this variation contributes to the development of diabetic nephropathy (DN) in type 2 diabetes. A case-control study was performed of 291 non-diabetic control subjects and 466 patients with type 2 diabetes, of whom 238 had DN with overt albuminuria (DN group; albuminuric excretion rate [AER] ≥ 300 mg/24 h) and 228 did not have DN, but had diabetes for more than 10 years (non-DN group). Genotyping was performed using a TaqMan PCR assay. The Leu/Leu, Leu/Met, and Met/Met genotype frequencies were significantly different between the non-DN and DN groups (p = 0.011). The frequency of the variant genotypes (Leu/Met, Met/Met) was significantly lower in the DN group than the non-DN group (23.5 vs. 36.0 %, p = 0.003). Met/Met non-diabetic control subjects had lower BMI and Scr levels and higher eGFR level than Leu/Leu or Leu/Met individuals (p < 0.05). Leu/Met and Met/Met type 2 diabetics had significantly lower AER and Scr levels and higher eGFR level than Leu/Leu type 2 diabetics (all p < 0.001). The GHRL Leu72Met polymorphism may help to maintain normal renal function and may protect against the development of DN by reducing albuminuria and improving renal function in Chinese patients with type 2 diabetes.

INFLUENCE OF LIGHT ON BACTERIOPLANKTON PRODUCTION AND RESPIRATION IN A SUBTROPICAL CORAL REEF

EPA Science Inventory

The influence of sunlight on bacterioplankton production (14C-leucine (Leu) and 3H-thymidine (TdR) incorporation; changes in cell abundances) and O2 consumption was investigated in a shallow subtropical coral reef located near Key Largo, Florida. Quartz (light) and opaque (dark) ...

Contamination of animal feedingstuffs with undeclared antimicrobial additives.

PubMed

Lynas, L; Currie, D; McCaughey, W J; McEvoy, J D; Kennedy, D G

1998-01-01

A study was carried out on 397 feedingstuffs and 11 premixes on which 161 (39.5%) were declared free of medication and 247 (60.5%) were medicated. These were subjected to analysis for the presence of antibiotics. Of the 247 medicated feeds 87 (35.2%) contained undeclared antimicrobials of which 59 (23.9%) were at a concentration sufficient to allow quantification by HPLC. Of the 161 unmedicated feeds 71 (44.1%) were shown to contain detectable antimicrobials of which 42 (26.1%) contained concentrations which could be quantified by HPLC. The most frequently identified contaminating antimicrobials were chlortetracycline (CTC) (15.2%), sulphonamides (6.9%), penicillin (3.4%) and ionophores (3.4%). Four samples (ionophores--3, sulphadimidine--1) contained therapeutic concentrations and one sample a supra-therapeutic concentration (monensin). The remainder were sub-therapeutic. All the contaminating concentrations of sulphadimidine detected were sufficient to cause violative tissue residues if fed to animals immediately prior to slaughter.

The RERTR Program status and progress

DOE Office of Scientific and Technical Information (OSTI.GOV)

Travelli, A.

1995-12-01

The progress of the Reduced Enrichment Research and Test Reactor (RERTR) Program is described. The major events, findings, and activities of 1995 are reviewed after a brief summary of the results which the RERTR Program had achieved by the end of 1994. The revelation that Iraq was on the verge of developing a nuclear weapon at the time of the Gulf War, and that it was planning to do so by extracting HEU from the fuel of its research reactors, has given new impetus and urgency to the RERTR commitment of eliminating HEU use in research and test reactors worldwide.more » Development of advanced LEU research reactor fuels is scheduled to begin in October 1995. The Russian RERTR program, which aims to develop and demonstrate within the next five years the technical means needed to convert Russian-supplied research reactors to LEU fuels, is now in operation. A Statement of Intent was signed by high US and Chinese officials, endorsing cooperative activities between the RERTR program and Chinese laboratories involved in similar activities. Joint studies of LEU technical feasibility were completed for the SAFARI-I reactor in South Africa and for the ANS reactor in the US. A new study has been initiated for the FRM-II reactor in Germany. Significant progress was made on several aspects of producing {sup 99}Mo from fission targets utilizing LEU instead of HEU. A cooperation agreements is in place with the Indonesian BATAN. The first prototypical irradiation of an LEU metal-foil target for {sup 99}Mo production was accomplished in Indonesia. The TR-2 reactor, in Turkey, began conversion. SAPHIR, in Switzerland, was shut down. LEU fuel fabrication has begun for the conversion of two more US reactors. Twelve foreign reactors and nine domestic reactors have been fully converted. Approximately 60 % of the work required to eliminate the use of HEU in US-supplied research reactors has been accomplished.« less

A Reload and Startup Plan for and #8233;Conversion of the NIST Research Reactor

DOE Office of Scientific and Technical Information (OSTI.GOV)

Diamond, D. J.; Varuttamaseni, A.

The National Institute of Standards and Technology operates a 20 MW research reactor for neutron-based research. The heavy-water moderated and cooled reactor is fueled with high-enriched uranium (HEU) but a program to convert the reactor to low-enriched uranium (LEU) fuel is underway. Among other requirements, a reload and startup test plan must be submitted to the U.S. Nuclear Regulatory Commission (NRC) for their approval. The NRC provides guidance for what should be in the plan to ensure that the licensee has sufficient information to operate the reactor safely. Hence, a plan has been generated consisting of two parts.The reload portionmore » of the plan specifies the fuel management whereby initially only two LEU fuel elements are in the core for eight fuel cycles. This is repeated until a point when the optimum approach is to place four fresh LEU elements into the reactor each cycle. This final transition is repeated and after eight cycles the reactor is completely fueled with LEU. By only adding two LEU fuel elements initially, the plan allows for the consumption of HEU fuel elements that are expected to be in storage at the time of conversion and provides additional qualification of production LEU fuel under actual operating conditions. Because the reload is to take place over many fuel cycles, startup tests will be done at different stages of the conversion. The tests, to be compared with calculations to show that the reactor will operate as planned, are the measurement of critical shim arm position and shim arm and regulating rod reactivity worths. An acceptance criterion for each test is specified based on technical specifications that relate to safe operation. Additional tests are being considered that have less safety significance but may be of interest to bolster the validation of analysis tools.« less

A reload and startup plan for conversion of the NIST research reactor

DOE Office of Scientific and Technical Information (OSTI.GOV)

D. J. Diamond

The National Institute of Standards and Technology operates a 20 MW research reactor for neutron-based research. The heavy-water moderated and cooled reactor is fueled with high-enriched uranium (HEU) but a program to convert the reactor to low-enriched uranium (LEU) fuel is underway. Among other requirements, a reload and startup test plan must be submitted to the U.S. Nuclear Regulatory Commission (NRC) for their approval. The NRC provides guidance for what should be in the plan to ensure that the licensee has sufficient information to operate the reactor safely. Hence, a plan has been generated consisting of two parts. The reloadmore » portion of the plan specifies the fuel management whereby initially only two LEU fuel elements are in the core for eight fuel cycles. This is repeated until a point when the optimum approach is to place four fresh LEU elements into the reactor each cycle. This final transition is repeated and after eight cycles the reactor is completely fueled with LEU. By only adding two LEU fuel elements initially, the plan allows for the consumption of HEU fuel elements that are expected to be in storage at the time of conversion and provides additional qualification of production LEU fuel under actual operating conditions. Because the reload is to take place over many fuel cycles, startup tests will be done at different stages of the conversion. The tests, to be compared with calculations to show that the reactor will operate as planned, are the measurement of critical shim arm position and shim arm and regulating rod reactivity worths. An acceptance criterion for each test is specified based on technical specifications that relate to safe operation. Additional tests are being considered that have less safety significance but may be of interest to bolster the validation of analysis tools.« less

Effects of leucine and its metabolite β-hydroxy-β-methylbutyrate on human skeletal muscle protein metabolism

PubMed Central

Wilkinson, D J; Hossain, T; Hill, D S; Phillips, B E; Crossland, H; Williams, J; Loughna, P; Churchward-Venne, T A; Breen, L; Phillips, S M; Etheridge, T; Rathmacher, J A; Smith, K; Szewczyk, N J; Atherton, P J

2013-01-01

Maintenance of skeletal muscle mass is contingent upon the dynamic equilibrium (fasted losses–fed gains) in protein turnover. Of all nutrients, the single amino acid leucine (Leu) possesses the most marked anabolic characteristics in acting as a trigger element for the initiation of protein synthesis. While the mechanisms by which Leu is ‘sensed’ have been the subject of great scrutiny, as a branched-chain amino acid, Leu can be catabolized within muscle, thus posing the possibility that metabolites of Leu could be involved in mediating the anabolic effect(s) of Leu. Our objective was to measure muscle protein anabolism in response to Leu and its metabolite HMB. Using [1,2-13C2]Leu and [2H5]phenylalanine tracers, and GC-MS/GC-C-IRMS we studied the effect of HMB or Leu alone on MPS (by tracer incorporation into myofibrils), and for HMB we also measured muscle proteolysis (by arteriovenous (A–V) dilution). Orally consumed 3.42 g free-acid (FA-HMB) HMB (providing 2.42 g of pure HMB) exhibited rapid bioavailability in plasma and muscle and, similarly to 3.42 g Leu, stimulated muscle protein synthesis (MPS; HMB +70%vs. Leu +110%). While HMB and Leu both increased anabolic signalling (mechanistic target of rapamycin; mTOR), this was more pronounced with Leu (i.e. p70S6K1 signalling ≤90 min vs. ≤30 min for HMB). HMB consumption also attenuated muscle protein breakdown (MPB; −57%) in an insulin-independent manner. We conclude that exogenous HMB induces acute muscle anabolism (increased MPS and reduced MPB) albeit perhaps via distinct, and/or additional mechanism(s) to Leu. PMID:23551944

Association of the F13A1 Val34Leu polymorphism and recurrent pregnancy loss: A meta-analysis.

PubMed

Jung, Jae Hyun; Kim, Jae-Hoon; Song, Gwan Gyu; Choi, Sung Jae

2017-08-01

Factor XIII (FXIII) plays role in stabilizing the linkage between fibrins during blood clotting and has been implicated in recurrent pregnancy loss (RPL). The relationship between the Val34Leu polymorphism in F13A1, which encodes the enzymatic subunit of FXIII, and RPL is unclear. The aim of this meta-analysis was to evaluate the association betweenF13A1 Val34Leu and the risk of RPL. We performed a meta-analysis of 11 studies involving 1092 cases and 678 controls using published literature from PubMed and Embase. We detected an association in recessive (Val/Val vs. Val/Leu+Leu/Leu; OR=0.71, 95% CI=0.51-0.99, P=0.04), and one of the two co-dominant (Val/Val vs. Val/Leu; OR=0.71, 95% CI=0.52-0.98, P=0.03) models of in heritance. Subgroup analysis revealed that the F13A1 Val34Leu polymorphism was associated with RPL in Asians (Val vs. Leu; OR=0.53, CI=0.33-0.85, P=0.01). However, there was no association between F13A1 Val34Leu and RPL in Europeans and South Americans. Our meta-analysis supports an association between F13A1 Val34Leu and RPL. Copyright © 2017 Elsevier B.V. All rights reserved.

Peptide (Lys-Leu) and amino acids (Lys and Leu) supplementations improve physiological activity and fermentation performance of brewer's yeast during very high-gravity (VHG) wort fermentation.

PubMed

Yang, Huirong; Zong, Xuyan; Cui, Chun; Mu, Lixia; Zhao, Haifeng

2017-12-22

Lys and Leu were generally considered as the key amino acids for brewer's yeast during beer brewing. In the present study, peptide Lys-Leu and a free amino acid (FAA) mixture of Lys and Leu (Lys + Leu) were supplemented in 24 °P wort to examine their effects on physiological activity and fermentation performance of brewer's yeast during very high-gravity (VHG) wort fermentation. Results showed that although both peptide Lys-Leu and their FAA mixture supplementations could increase the growth and viability, intracellular trehalose and glycerol content, wort fermentability, and ethanol content for brewer's yeast during VHG wort fermentation, and peptide was better than their FAA mixture at promoting growth and fermentation for brewer's yeast when the same dose was kept. Moreover, peptide Lys-Leu supplementation significantly increased the assimilation of Asp, but decreased the assimilation of Gly, Ala, Val, (Cys)2, Ile, Leu, Tyr, Phe, Lys, Arg, and Pro. However, the FAA mixture supplementation only promoted the assimilation of Lys and Leu, while reduced the absorption of total amino acids to a greater extent. Thus, the peptide Lys-Leu was more effective than their FAA mixture on the improvement of physiological activity, fermentation performance, and nitrogen metabolism of brewer's yeast during VHG wort fermentation. © 2017 International Union of Biochemistry and Molecular Biology, Inc.

Approach to proliferation risk assessment based on multiple objective analysis framework

DOE Office of Scientific and Technical Information (OSTI.GOV)

Andrianov, A.; Kuptsov, I.; Studgorodok 1, Obninsk, Kaluga region, 249030

2013-07-01

The approach to the assessment of proliferation risk using the methods of multi-criteria decision making and multi-objective optimization is presented. The approach allows the taking into account of the specifics features of the national nuclear infrastructure, and possible proliferation strategies (motivations, intentions, and capabilities). 3 examples of applying the approach are shown. First, the approach has been used to evaluate the attractiveness of HEU (high enriched uranium)production scenarios at a clandestine enrichment facility using centrifuge enrichment technology. Secondly, the approach has been applied to assess the attractiveness of scenarios for undeclared production of plutonium or HEU by theft of materialsmore » circulating in nuclear fuel cycle facilities and thermal reactors. Thirdly, the approach has been used to perform a comparative analysis of the structures of developing nuclear power systems based on different types of nuclear fuel cycles, the analysis being based on indicators of proliferation risk.« less

Biochemical and Structural Insights into Enzymatic Depolymerization of Polylactic Acid and Other Polyesters by Microbial Carboxylesterases.

PubMed

Hajighasemi, Mahbod; Nocek, Boguslaw P; Tchigvintsev, Anatoli; Brown, Greg; Flick, Robert; Xu, Xiaohui; Cui, Hong; Hai, Tran; Joachimiak, Andrzej; Golyshin, Peter N; Savchenko, Alexei; Edwards, Elizabeth A; Yakunin, Alexander F

2016-06-13

Polylactic acid (PLA) is a biodegradable polyester derived from renewable resources, which is a leading candidate for the replacement of traditional petroleum-based polymers. Since the global production of PLA is quickly growing, there is an urgent need for the development of efficient recycling technologies, which will produce lactic acid instead of CO2 as the final product. After screening 90 purified microbial α/β-hydrolases, we identified hydrolytic activity against emulsified PLA in two uncharacterized proteins, ABO2449 from Alcanivorax borkumensis and RPA1511 from Rhodopseudomonas palustris. Both enzymes were also active against emulsified polycaprolactone and other polyesters as well as against soluble α-naphthyl and p-nitrophenyl monoesters. In addition, both ABO2449 and RPA1511 catalyzed complete or extensive hydrolysis of solid PLA with the production of lactic acid monomers, dimers, and larger oligomers as products. The crystal structure of RPA1511 was determined at 2.2 Å resolution and revealed a classical α/β-hydrolase fold with a wide-open active site containing a molecule of polyethylene glycol bound near the catalytic triad Ser114-His270-Asp242. Site-directed mutagenesis of both proteins demonstrated that the catalytic triad residues are important for the hydrolysis of both monoester and polyester substrates. We also identified several residues in RPA1511 (Gln172, Leu212, Met215, Trp218, and Leu220) and ABO2449 (Phe38 and Leu152), which were not essential for activity against soluble monoesters but were found to be critical for the hydrolysis of PLA. Our results indicate that microbial carboxyl esterases can efficiently hydrolyze various polyesters making them attractive biocatalysts for plastics depolymerization and recycling.

Synergistic effect with Phe-Gly-Leu-Met-NH2 of the C-terminal of substance P and insulin-like growth factor-1 on epithelial wound healing of rabbit cornea

PubMed Central

Nakamura, Masatsugu; Chikama, Tai-ichiro; Nishida, Teruo

1999-01-01

We previously reported that substance P and insulin-like growth factor-1 (IGF-1) synergistically stimulate corneal epithelial wound healing in vitro and in vivo. We wished to identify which portion of the amino acid sequence of substance P might be responsible for this synergism.Corneal epithelial migration was not affected by the addition of any one of the following factors: substance P; Phe-Gly-Leu-Met-NH2 (C-terminal of substance P); Val-Gly-Leu-Met-NH2 (C-terminal of neurokinin A, neurokinin B, and kassinin); Tyr-Gly-Leu-Met-NH2 (C-terminal of physalaemin); Ile-Gly-Leu-Met-NH2 (C-terminal of eledoisin); or Gly-Leu-Met-NH2 (common C-terminal of tachykinins).In the presence of IGF-1, only substance P and Phe-Gly-Leu-Met-NH2 were synergistic in stimulating corneal epithelial migration in a dose-dependent fashion.The combination of Phe-Gly-Leu-Met-NH2 and IGF-1 did not affect the incorporation of [3H]-thymidine into corneal epithelial cells.Treatment with Phe-Gly-Leu-Met-NH2 and IGF-1, but not with Phe-Gly-Leu-Met-NH2 or IGF-1 alone, increased attachment of corneal epithelial cells to a fibronectin matrix.The levels of α5 and β1 integrin were not affected by Phe-Gly-Leu-Met-NH2 or IGF-1 alone, but they were significantly increased by the combination of Phe-Gly-Leu-Met-NH2 and IGF-1.Topical application of the same combination facilitated corneal epithelial wound closure in vivo.These results demonstrated that Phe-Gly-Leu-Met-NH2, a sequence of 4 amino-acids of the C-terminal of substance P, is the minimum sequence necessary to produce the synergistic effects of substance P and IGF-1 on corneal epithelial wound healing. PMID:10385250

Update On The Development, Testing, And Manufacture Of High Density LEU-Foil Targets For The Production Of Mo-99

DOE Office of Scientific and Technical Information (OSTI.GOV)

Creasy, John T

2015-05-12

This project has the objective to reduce and/or eliminate the use of HEU in commerce. Steps in the process include developing a target testing methodology that is bounding for all Mo-99 target irradiators, establishing a maximum target LEU-foil mass, developing a LEU-foil target qualification document, developing a bounding target failure analysis methodology (failure in reactor containment), optimizing safety vs. economics (goal is to manufacture a safe, but relatively inexpensive target to offset the inherent economic disadvantage of using LEU in place of HEU), and developing target material specifications and manufacturing QC test criteria. The slide presentation is organized under themore » following topics: Objective, Process Overview, Background, Team Structure, Key Achievements, Experiment and Activity Descriptions, and Conclusions. The High Density Target project has demonstrated: approx. 50 targets irradiated through domestic and international partners; proof of concept for two front end processing methods; fabrication of uranium foils for target manufacture; quality control procedures and steps for manufacture; multiple target assembly techniques; multiple target disassembly devices; welding of targets; thermal, hydraulic, and mechanical modeling; robust target assembly parametric studies; and target qualification analysis for insertion into very high flux environment. The High Density Target project has tested and proven several technologies that will benefit current and future Mo-99 producers.« less

SAFARI-1: Achieving conversion to LEU - A local challenge

DOE Office of Scientific and Technical Information (OSTI.GOV)

Piani, C.S.B.

2008-07-15

Two years have passed since the South African Department of Minerals and Energy authorised the conversion from High Enriched Uranium (HEU) to Low Enriched Uranium (LEU) of the South African Research Reactor (SAFARI-1) and the associated fuel manufacturing at Pelindaba. The scheduling, as originally proposed, allowed approximately three years for the full conversion of the reactor, anticipating simultaneous manufacturing ability from the fuel production plant. Due to technical difficulties experienced in the conversion of the local manufacturing plant from HEU (UAl alloy) to LEU (U Silicide) and the uncertainty as to costing and scheduling of such an achievement, the conversionmore » of SAFARI-1 based on local supply has been allocated a lower priority. The acquisition in mid-2006 of 2 LEU silicide elements of SA design, manufactured by AREVA- CERCA and irradiated as test elements in SAFARI-1 to burn-ups of {approx}65% each; was successfully accomplished within 9 cycles of irradiation each. Furthermore, four 'Hybrid' elements (AREVA-CERCA plates assembled locally at Pelindaba) are ready for irradiation and have received regulatory authorisation to load. This will enable the SAFARI-1 conversion program to continue systematically according to an agreed schedule. This paper will trace the developments of the above and reflect the current status and the rescheduled conversion phases of the reactor according to latest expectations. (author)« less

Identification of antimicrobial compound, diketopiperazines, from a Bacillus sp. N strain associated with a rhabditid entomopathogenic nematode against major plant pathogenic fungi.

PubMed

Nishanth Kumar, S; Mohandas, C; Siji, J V; Rajasekharan, K N; Nambisan, Bala

2012-10-01

To purify and characterize antimicrobial compounds from Bacillus sp. strain N associated with rhabditid entomopathogenic nematode (EPN). The cell-free culture filtrate of a bacterium associated with an EPN, Rhabditis (Oscheius) sp., exhibited strong antimicrobial activity. The ethyl acetate extract of the bacterial culture filtrate was purified by silica gel column chromatography to obtain three diketopiperazines (DKPs). The structure and absolute stereochemistry of this compound were determined based on extensive spectroscopic analyses (FABMS, (1) H NMR, (13) C NMR, (1) H-(1) H COSY, (1) H-(13) C HMBC) and Marfey's method. The compounds were identified as cyclo(l-Pro-l-Leu), cyclo(d-Pro-l-Leu) and cyclo(d-Pro-l-Tyr), respectively. Three DKPs were active against all the five fungi tested (Aspergillus flavus, Candida albicans, Fusarium oxysporum, Rhizoctonia solani and Penicillium expansum) and are more effective than the standard fungicide bavistin. The highest activity of 4 μg ml(-1) by cyclo(l-Pro-l-Leu) and cyclo(d-Pro-l-Tyr) was recorded against P. expansum, a plant pathogen responsible for causing postharvest decay of stored apples and oranges. Cyclo(d-Pro-l-Leu) recorded good antibacterial activity against all the four bacteria tested (Bacillus subtilis, Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa), and cyclo(l-Pro-l-Leu) and cyclo(d-Pro-l-Tyr) recorded good activity only against Gram-positive bacteria. To our knowledge, this is the first report of antifungal activity of the DKPs against the plant pathogenic fungi F. oxysporum, R. solani and P. expansum. The production of cyclo(l-Pro-l-Leu), cyclo(d-Pro-l-Leu) and cyclo-(d-Pro-l-Tyr) by a bacterium associated with EPN is also reported here for the first time. Isolated DKPs demonstrated high antimicrobial activity against bacteria and fungi, especially against plant pathogenic fungi. We conclude that the bacterium associated with EPN is a promising source of natural bioactive secondary metabolites which may receive great benefit in the field of agriculture. This study is a significant contribution to the knowledge of compounds unique from EPN bacteria as potential sources of new drugs in the agricultural and pharmacological industry. © 2012 The Authors Journal of Applied Microbiology © 2012 The Society for Applied Microbiology.

The U.S. RERTR program status and progress.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Travelli, A.

1998-01-21

The progress of the Reduced Enrichment Research and Test Reactor (RERTR) Program since its inception in 1978 is described. A brief summary of the results which the RERTR Program had achieved by the end of 1996 in collaboration with its many international partners is followed by a detailed review of the major events, findings, and activities of 1997. Significant progress has been made during the past year. In the area of U.S. acceptance of spent fuel from foreign research reactors, several shipments have taken place and additional are being planned. Intense fuel development activities are in progress, including procurement ofmore » equipment, screening of candidate materials, and production of microplates. Irradiation of the first series of microplates began in August 1997 in the Advanced Test Reactor, in Idaho. Progress has been made in the Russian RERTR program, which aims to develop and demonstrate within five years the technical means needed to convert Russian-supplied research reactors to LEU fuels. The study of an alternative LEU core for the FRM-II design has been extended to address, with favorable results, controversial performance issues which were raised at last year's meeting. Progress was also made on several aspects of producing molybdenum-99 from fission targets utilizing LEU instead of HEU. Various types of targets and processes are being pursued, with FDA approval of an LEU process projected to occur within two years. The feasibility of LEU Fuel conversion for three important DOE research reactors (BMRR, HFBR, and HFIR) has been evaluated by the RERTR program. In spite of the many momentous events which have occurred during the intervening years, and the excellent progress achieved, the most important challenges that the RERTR program faces today are not very different in type from those that were faced during the first RERTR meeting. Now, as then, the most important task is to develop new LEU fuels satisfying requirements which cannot be satisfied by any existing fuel. These new advanced fuels will enable conversion of the reactors which cannot be converted today, ensure better efficiency and performance for all research reactors, and allow the design of more powerful new advanced LEU reactors. As in the past, the success of the RERTR program will depend on free exchange of ideas and information, and on the international friendship and cooperation that have been a trademark of the RERTR program since its inception.« less

Synergistic algicidal effect and mechanism of two diketopiperazines produced by Chryseobacterium sp. strain GLY-1106 on the harmful bloom-forming Microcystis aeruginosa

NASA Astrophysics Data System (ADS)

Guo, Xingliang; Liu, Xianglong; Pan, Jianliang; Yang, Hong

2015-10-01

A potent algicidal bacterium isolated from Lake Taihu, Chryseobacterium sp. strain GLY-1106, produces two algicidal compounds: 1106-A (cyclo(4-OH-Pro-Leu)) and 1106-B (cyclo(Pro-Leu)). Both diketopiperazines showed strong algicidal activities against Microcystis aeruginosa, the dominant bloom-forming cyanobacterium in Lake Taihu. Interestingly, these two algicidal compounds functioned synergistically. Compared with individual treatment, combined treatment with cyclo(4-OH-Pro-Leu) and cyclo(Pro-Leu) significantly enhanced algicidal activity, accelerated the increase in intracellular reactive oxygen species (ROS) levels in M. aeruginosa, and further decreased the activities of antioxidases, effective quantum yield and maximal electron transport rate of M. aeruginosa. The results also showed that the algicidal characteristics of cyclo(4-OH-Pro-Leu) are distinct from those of cyclo(Pro-Leu). Cyclo(4-OH-Pro-Leu) mainly interrupted the flux of electron transport in the cyanobacterial photosynthetic system, whereas cyclo(Pro-Leu) mainly inhibited the activity of cyanobacterial intracellular antioxidases. A possible algicidal mechanism for the synergism between cyclo(4-OH-Pro-Leu) and cyclo(Pro-Leu) is proposed, which is in accordance with their distinct algicidal characteristics in individual and combined treatment. These findings suggest that synergism between algicidal compounds might be used as an effective strategy for the future control of Microcystis blooms.

Synergistic algicidal effect and mechanism of two diketopiperazines produced by Chryseobacterium sp. strain GLY-1106 on the harmful bloom-forming Microcystis aeruginosa

PubMed Central

Guo, Xingliang; Liu, Xianglong; Pan, Jianliang; Yang, Hong

2015-01-01

A potent algicidal bacterium isolated from Lake Taihu, Chryseobacterium sp. strain GLY-1106, produces two algicidal compounds: 1106-A (cyclo(4-OH-Pro-Leu)) and 1106-B (cyclo(Pro-Leu)). Both diketopiperazines showed strong algicidal activities against Microcystis aeruginosa, the dominant bloom-forming cyanobacterium in Lake Taihu. Interestingly, these two algicidal compounds functioned synergistically. Compared with individual treatment, combined treatment with cyclo(4-OH-Pro-Leu) and cyclo(Pro-Leu) significantly enhanced algicidal activity, accelerated the increase in intracellular reactive oxygen species (ROS) levels in M. aeruginosa, and further decreased the activities of antioxidases, effective quantum yield and maximal electron transport rate of M. aeruginosa. The results also showed that the algicidal characteristics of cyclo(4-OH-Pro-Leu) are distinct from those of cyclo(Pro-Leu). Cyclo(4-OH-Pro-Leu) mainly interrupted the flux of electron transport in the cyanobacterial photosynthetic system, whereas cyclo(Pro-Leu) mainly inhibited the activity of cyanobacterial intracellular antioxidases. A possible algicidal mechanism for the synergism between cyclo(4-OH-Pro-Leu) and cyclo(Pro-Leu) is proposed, which is in accordance with their distinct algicidal characteristics in individual and combined treatment. These findings suggest that synergism between algicidal compounds might be used as an effective strategy for the future control of Microcystis blooms. PMID:26423356

Synergistic algicidal effect and mechanism of two diketopiperazines produced by Chryseobacterium sp. strain GLY-1106 on the harmful bloom-forming Microcystis aeruginosa.

PubMed

Guo, Xingliang; Liu, Xianglong; Pan, Jianliang; Yang, Hong

2015-10-01

A potent algicidal bacterium isolated from Lake Taihu, Chryseobacterium sp. strain GLY-1106, produces two algicidal compounds: 1106-A (cyclo(4-OH-Pro-Leu)) and 1106-B (cyclo(Pro-Leu)). Both diketopiperazines showed strong algicidal activities against Microcystis aeruginosa, the dominant bloom-forming cyanobacterium in Lake Taihu. Interestingly, these two algicidal compounds functioned synergistically. Compared with individual treatment, combined treatment with cyclo(4-OH-Pro-Leu) and cyclo(Pro-Leu) significantly enhanced algicidal activity, accelerated the increase in intracellular reactive oxygen species (ROS) levels in M. aeruginosa, and further decreased the activities of antioxidases, effective quantum yield and maximal electron transport rate of M. aeruginosa. The results also showed that the algicidal characteristics of cyclo(4-OH-Pro-Leu) are distinct from those of cyclo(Pro-Leu). Cyclo(4-OH-Pro-Leu) mainly interrupted the flux of electron transport in the cyanobacterial photosynthetic system, whereas cyclo(Pro-Leu) mainly inhibited the activity of cyanobacterial intracellular antioxidases. A possible algicidal mechanism for the synergism between cyclo(4-OH-Pro-Leu) and cyclo(Pro-Leu) is proposed, which is in accordance with their distinct algicidal characteristics in individual and combined treatment. These findings suggest that synergism between algicidal compounds might be used as an effective strategy for the future control of Microcystis blooms.

Preproghrelin Leu72Met polymorphism in Chinese subjects with coronary artery disease and controls.

PubMed

Tang, Na-Ping; Wang, Lian-Sheng; Yang, Li; Gu, Hai-Juan; Zhu, Huai-Jun; Zhou, Bo; Sun, Qing-Min; Cong, Ri-Hong; Wang, Bin

2008-01-01

Ghrelin, a novel endogenous ligand for the growth hormone secretagogue receptor, is considered to exert a protective effect against atherosclerosis. The Leu72Met (+408C>A) polymorphic variant of the preproghrelin, the gene for the ghrelin precursor, has been linked to obesity, diabetes and metabolic syndrome. However, it is unclear whether this polymorphism is associated with coronary artery disease (CAD). We conducted a case-control study with 317 CAD patients and 323 controls to investigate the potential association of the Leu72Met polymorphism with the occurrence of CAD and CAD-related phenotypes in Chinese population. No significant difference in the Leu72Met genotype frequency was observed between CAD patients and controls (P=NS). The Leu72Met polymorphism was not associated with hypertension, diabetes, dyslipidemia, the number of diseased vessels, plasma total cholesterol, triglyceride, high density lipoprotein cholesterol, low density lipoprotein cholesterol or fasting glucose levels in CAD patients. However, among CAD patients, those with variant genotypes (Leu72Met and Met72Met) had lower BMI (24.4+/-0.3 kg/m(2)) than Leu72Leu carriers (25.4+/-0.2 kg/m(2), adjusted P=0.033). Our data indicate that the preproghrelin Leu72Met polymorphism is not associated with CAD in Chinese population. However, the Leu72Met variant is associated with BMI among CAD patients.

Cathepsin D immobilized capillary reactors for on-flow screening assays.

PubMed

Cornelio, Vivian Estevam; de Moraes, Marcela Cristina; Domingues, Vanessa de Cassia; Fernandes, João Batista; da Silva, Maria Fátima das Gracas Fernandes; Cass, Quezia Bezerra; Vieira, Paulo Cezar

2018-03-20

The treatment of diseases using enzymes as targets has called for the development of new and reliable methods for screening. The protease cathepsin D is one such target involved in several diseases such as tumors, degenerative processes, and vital processes of parasites causing schistosomiasis. Herein, we describe the preparation of a fused silica capillary, cathepsin D (CatD)-immobilized enzyme reactor (IMER) using in a multidimensional High Performance Liquid Chromatography-based method (2D-HPLC) and zonal affinity chromatography as an alternative in the search for new ligands. The activity and kinetic parameters of CatD-IMER were evaluated by monitoring the product MOCAc-Gly-Lys-Pro-Ile-Leu-Phe (P-MOCAc) (K M  = 81.9 ± 7.49 μmol/L) generated by cleavage of the fluorogenic substrate MOCAc-Gly-Lys-Pro-Ile-Leu-Phe-Phe-Arg-Leu-Lys(DNP)-d-Arg-NH2 (S-MOCAc). Stability studies have indicated that CatD-IMER retained 20% of activity after 5 months, a relevant result, because proteases are susceptible to autoproteolysis in solution assays with free enzyme. In the search for inhibitors, 12 crude natural product extracts were analyzed using CatD-IMER as the target, resulting in the isolation of different classes of natural products. In addition, 26 compounds obtained from different species of plants were also screened, demonstrating the efficiency and reproducibility of the herein reported assay even in the case of complex matrices such as plant crude extracts. Copyright © 2018 Elsevier B.V. All rights reserved.

Scalability of the LEU-Modified Cintichem Process: 3-MeV Van de Graaff and 35-MeV Electron Linear Accelerator Studies

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rotsch, David A.; Brossard, Tom; Roussin, Ethan

Molybdenum-99, the mother of Tc-99m, can be produced from fission of U-235 in nuclear reactors and purified from fission products by the Cintichem process, later modified for low-enriched uranium (LEU) targets. The key step in this process is the precipitation of Mo with α-benzoin oxime (ABO). The stability of this complex to radiation has been examined. Molybdenum-ABO was irradiated with 3 MeV electrons produced by a Van de Graaff generator and 35 MeV electrons produced by a 50 MeV/25 kW electron linear accelerator. Dose equivalents of 1.7–31.2 kCi of Mo-99 were administered to freshly prepared Mo-ABO. Irradiated samples of Mo-ABOmore » were processed according to the LEU Modified-Cintichem process. The Van de Graaff data indicated good radiation stability of the Mo-ABO complex up to ~15 kCi dose equivalents of Mo-99 and nearly complete destruction at doses >24 kCi Mo-99. The linear accelerator data indicate that even at 6.2 kCi of Mo-99 equivalence of dose, the sample lost ~20% of Mo-99. The 20% loss of Mo-99 at this low dose may be attributed to thermal decomposition of the product from the heat deposited in the sample during irradiation.« less

Molecular Dynamics and Free Energy Simulations of Phenylacetate and CO2 Release from AMDase and Its G74C/C188S Mutant: A Possible Rationale for the Reduced Activity of the Latter.

PubMed

Karmakar, Tarak; Balasubramanian, Sundaram

2016-11-17

Arylmalonate decarboxylase (AMDase) catalyzes the decarboxylation of α-aryl-α-methyl malonates to produce optically pure α-arylpropionates of industrial and medicinal importance. Herein, atomistic molecular dynamics simulations have been carried out to delineate the mechanism of the release of product molecules phenylacetate (PAC) and carbon dioxide (CO 2 ), from the wild-type (WT) and its G74C/C188S mutant enzymes. Both of the product molecules follow a crystallographically characterized solvent-accessible channel to come out of the protein interior. A higher free energy barrier for the release of PAC from G74C/C188S compared to that in the WT is consistent with the experimentally observed compromised efficiency of the mutant. The release of CO 2 precedes that of PAC; free energy barriers for CO 2 and PAC release in the WT enzyme are calculated to be ∼1-2 and ∼23 kcal/mol, respectively. Postdecarboxylation, CO 2 moves toward a hydrophobic pocket formed by Pro 14, Leu 38, Leu 40, Leu 77, and the side chain of Tyr 48 which serves as its temporary "reservoir". CO 2 releases following a channel mainly decorated by apolar residues, unlike in the case of oxalate decarboxylase where polar residues mediate its transport.

LAPTM4b recruits the LAT1-4F2hc Leu transporter to lysosomes and promotes mTORC1 activation.

PubMed

Milkereit, Ruth; Persaud, Avinash; Vanoaica, Liviu; Guetg, Adriano; Verrey, Francois; Rotin, Daniela

2015-05-22

Mammalian target of rapamycin 1 (mTORC1), a master regulator of cellular growth, is activated downstream of growth factors, energy signalling and intracellular essential amino acids (EAAs) such as Leu. mTORC1 activation occurs at the lysosomal membrane, and involves V-ATPase stimulation by intra-lysosomal EAA (inside-out activation), leading to activation of the Ragulator, RagA/B-GTP and mTORC1 via Rheb-GTP. How Leu enters the lysosomes is unknown. Here we identified the lysosomal protein LAPTM4b as a binding partner for the Leu transporter, LAT1-4F2hc (SLC7A5-SLAC3A2). We show that LAPTM4b recruits LAT1-4F2hc to lysosomes, leading to uptake of Leu into lysosomes, and is required for mTORC1 activation via V-ATPase following EAA or Leu stimulation. These results demonstrate a functional Leu transporter at the lysosome, and help explain the inside-out lysosomal activation of mTORC1 by Leu/EAA.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Colantonio, Patrizia; Leboffe, Loris; Bolli, Alessandro

Caspase-3 is responsible for the cleavage of several proteins including the nuclear enzyme poly(ADP-ribose) polymerase (PARP). Designed on the cleavage site of PARP, Ac-Asp-Glu-Val-Asp-H has been reported as a highly specific inhibitor. To overcome the susceptibility to proteolysis, the intrinsic instability, and the scarce membrane permeability of tetra-peptidyl aldehydes, di- and tri-peptidyl caspase-3 inhibitors have been synthesized. Here, the synthesis and the inhibition properties of peptidyl aldehydes Z-tLeu-Asp-H, Z-tLeu-Val-Asp-H, and Z-Val-tLeu-Asp-H are reported. Z-tLeu-Asp-H, Z-tLeu-Val-Asp-H, and Z-Val-tLeu-Asp-H inhibit competitively human caspase-3 activity in vitro with K{sub i}{sup 0} = 3.6 nM, 18.2 nM, and 109 nM, respectively (pH 7.4 andmore » 25 deg. C). Moreover, Z-tLeu-Asp-H impairs apoptosis in human DLD-1 colon adenocarcinoma cells without affecting caspase-8. Therefore, Ac-Asp-Glu-Val-Asp-H can be truncated to Z-tLeu-Asp-H retaining nanomolar inhibitory activity in vitro and displaying action in whole cells, these properties reflect the unprecedented introduction of the bulky and lipophilic tLeu residue at the P{sub 2} position.« less

Energy landscape of LeuT from molecular simulations

NASA Astrophysics Data System (ADS)

Gur, Mert; Zomot, Elia; Cheng, Mary Hongying; Bahar, Ivet

2015-12-01

The bacterial sodium-coupled leucine transporter (LeuT) has been broadly used as a structural model for understanding the structure-dynamics-function of mammalian neurotransmitter transporters as well as other solute carriers that share the same fold (LeuT fold), as the first member of the family crystallographically resolved in multiple states: outward-facing open, outward-facing occluded, and inward-facing open. Yet, a complete picture of the energy landscape of (sub)states visited along the LeuT transport cycle has been elusive. In an attempt to visualize the conformational spectrum of LeuT, we performed extensive simulations of LeuT dimer dynamics in the presence of substrate (Ala or Leu) and co-transported Na+ ions, in explicit membrane and water. We used both conventional molecular dynamics (MD) simulations (with Anton supercomputing machine) and a recently introduced method, collective MD, that takes advantage of collective modes of motions predicted by the anisotropic network model. Free energy landscapes constructed based on ˜40 μs trajectories reveal multiple substates occluded to the extracellular (EC) and/or intracellular (IC) media, varying in the levels of exposure of LeuT to EC or IC vestibules. The IC-facing transmembrane (TM) helical segment TM1a shows an opening, albeit to a smaller extent and in a slightly different direction than that observed in the inward-facing open crystal structure. The study provides insights into the spectrum of conformational substates and paths accessible to LeuT and highlights the differences between Ala- and Leu-bound substates.

Energy landscape of LeuT from molecular simulations.

PubMed

Gur, Mert; Zomot, Elia; Cheng, Mary Hongying; Bahar, Ivet

2015-12-28

The bacterial sodium-coupled leucine transporter (LeuT) has been broadly used as a structural model for understanding the structure-dynamics-function of mammalian neurotransmitter transporters as well as other solute carriers that share the same fold (LeuT fold), as the first member of the family crystallographically resolved in multiple states: outward-facing open, outward-facing occluded, and inward-facing open. Yet, a complete picture of the energy landscape of (sub)states visited along the LeuT transport cycle has been elusive. In an attempt to visualize the conformational spectrum of LeuT, we performed extensive simulations of LeuT dimer dynamics in the presence of substrate (Ala or Leu) and co-transported Na(+) ions, in explicit membrane and water. We used both conventional molecular dynamics (MD) simulations (with Anton supercomputing machine) and a recently introduced method, collective MD, that takes advantage of collective modes of motions predicted by the anisotropic network model. Free energy landscapes constructed based on ∼40 μs trajectories reveal multiple substates occluded to the extracellular (EC) and/or intracellular (IC) media, varying in the levels of exposure of LeuT to EC or IC vestibules. The IC-facing transmembrane (TM) helical segment TM1a shows an opening, albeit to a smaller extent and in a slightly different direction than that observed in the inward-facing open crystal structure. The study provides insights into the spectrum of conformational substates and paths accessible to LeuT and highlights the differences between Ala- and Leu-bound substates.

Energy landscape of LeuT from molecular simulations

PubMed Central

Gur, Mert; Zomot, Elia; Cheng, Mary Hongying; Bahar, Ivet

2015-01-01

The bacterial sodium-coupled leucine transporter (LeuT) has been broadly used as a structural model for understanding the structure-dynamics-function of mammalian neurotransmitter transporters as well as other solute carriers that share the same fold (LeuT fold), as the first member of the family crystallographically resolved in multiple states: outward-facing open, outward-facing occluded, and inward-facing open. Yet, a complete picture of the energy landscape of (sub)states visited along the LeuT transport cycle has been elusive. In an attempt to visualize the conformational spectrum of LeuT, we performed extensive simulations of LeuT dimer dynamics in the presence of substrate (Ala or Leu) and co-transported Na+ ions, in explicit membrane and water. We used both conventional molecular dynamics (MD) simulations (with Anton supercomputing machine) and a recently introduced method, collective MD, that takes advantage of collective modes of motions predicted by the anisotropic network model. Free energy landscapes constructed based on ∼40 μs trajectories reveal multiple substates occluded to the extracellular (EC) and/or intracellular (IC) media, varying in the levels of exposure of LeuT to EC or IC vestibules. The IC-facing transmembrane (TM) helical segment TM1a shows an opening, albeit to a smaller extent and in a slightly different direction than that observed in the inward-facing open crystal structure. The study provides insights into the spectrum of conformational substates and paths accessible to LeuT and highlights the differences between Ala- and Leu-bound substates. PMID:26723619

Interactive effects of dietary leucine and isoleucine on growth, blood parameters, and amino acid profile of Japanese flounder Paralichthys olivaceus.

PubMed

Wang, Liping; Han, Yuzhe; Jiang, Zhiqiang; Sun, Menglei; Si, Bin; Chen, Fei; Bao, Ning

2017-10-01

A 60-day feeding trial was conducted to assess the interactions of dietary leucine (Leu) and isoleucine (Ile) on Japanese flounder. Fish of 2.69 ± 0.04 g were fed experimental diets containing two levels of Leu (2.58 and 5.08% of diet) combined with three levels of Ile (1.44, 2.21, and 4.44% of diet), respectively. After the feeding trial, growth, proximate composition, muscle total amino acid profile, blood parameters, mucus lysozyme activity, and stress tolerance to freshwater were measured. Statistically significant (P < 0.05) interactive effects of Leu and Ile were found on growth parameters (final body weight, body weight gain, and special growth rate) of Japanese flounder. Antagonism was discovered in high dietary Leu groups, while stimulatory effects were obtained for increased dietary Ile in low Leu groups. Interactive effects of these two branched-chain amino acids were also found on hepatosomatic index of test fish. In addition, crude lipid content of fish whole body was significantly altered by various diets, with antagonism observed in low dietary Leu groups. Interactive effects also existed in muscle amino acid profiles for low fish meal diets, but no interactive impacts were observed on blood parameters. Furthermore, lysozyme activities and freshwater stress were significantly affected by different diets. And antagonism was found on lysozyme activities in low Leu groups. Moreover, high Leu and high Ile levels of diet significantly altered freshwater stress tolerance of Japanese flounder. These findings suggested that dietary Leu and Ile can effect interactively, and fish fed with diets containing 2.58% Leu with 4.44% Ile and 5.08% Leu with 1.44% Ile showed better growth performance.

Leucine Promotes the Growth of Fetal Pigs by Increasing Protein Synthesis through the mTOR Signaling Pathway in Longissimus Dorsi Muscle at Late Gestation.

PubMed

Wang, Chao-Xian; Chen, Fang; Zhang, Wen-Fei; Zhang, Shi-Hai; Shi, Kui; Song, Han-Qing; Wang, Yi-Jiang; Kim, Sung Woo; Guan, Wu-Tai

2018-04-18

Leucine (Leu) plays an important role in protein synthesis and metabolism. The present study tested whether Leu supplementation in the diet for sows during late pregnancy could improve piglet birth weight, and it also investigated the possible underlying mechanism. Two hundred sows at day 70 of pregnancy were selected and assigned to four groups fed with following four diets until farrowing, respectively: corn and soybean meal-based diet group (CON), CON + 0.40% Leu, CON + 0.80% Leu, and CON + 1.20% Leu. We found that supplementing with 0.80% Leu significantly increased mean piglet birth weight ( P < 0.05). Supplementation with 0.40, 0.80, and 1.20% Leu increased the plasma concentration of Leu, while decreasing the plasma concentrations of valine (Val) and isoleucine (Ile) in both farrowing sows and newborn piglets ( P < 0.05). The protein expressions of amino acid transporters (including LAT1, SNAT1, SNAT2, 4F2hc, and rBAT) in duodenum, jejunum, ileum, longissimus dorsi muscle of newborn piglets, and placenta of sows showed a difference among the CON group and Leu supplemented groups. Expressions of p-mTOR, p-4E-BP1, and p-S6K1 in longissimus dorsi muscle were also enhanced in each of the supplemental Leu groups compared to CON ( P < 0.05). Collectively, these results indicated that 0.40-0.80% Leu supplementation during late gestation enhanced birth weight of fetal pigs by increasing protein synthesis through modulation of the plasma amino acids profile, amino acid transporters expression, and mTOR signaling pathway.

44 CFR 204.43 - Ineligible costs.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 44 Emergency Management and Assistance 1 2010-10-01 2010-10-01 false Ineligible costs. 204.43... Ineligible costs. Costs not directly associated with the incident period are ineligible. Ineligible costs include the following: (a) Costs incurred in the mitigation, management, and control of undeclared fires...

Protection from oxidative inactivation of the 20S proteasome by heat-shock protein 90.

PubMed Central

Conconi, M; Petropoulos, I; Emod, I; Turlin, E; Biville, F; Friguet, B

1998-01-01

Heat-shock protein 90 (Hsp 90) has been implicated in both protection against oxidative inactivation and inhibition of the multicatalytic proteinase (MCP, also known as 20 S proteasome). We report here that the protective and inhibitory effects of Hsp 90 depend on the activation state of the proteasome. Hsp 90 (and also alpha-crystallin) inhibits the N-Cbz-Leu-Leu-Leu-MCA-hydrolysing activity (Cbz=benzyloxycarbonyl; MCA=7-amido-4-methylcoumarin) when the rat liver MCP is in its latent form, but no inhibitory effects are observed when the MCP is in its active form. Metal-catalysed oxidation of the active MCP inactivates the Ala-Ala-Phe-MCA-hydrolysing (chymotrypsin-like), N-Boc-Leu-Ser-Thr-Arg-MCA-hydrolysing (trypsin-like; Boc=t-butyloxycarbonyl), N-Cbz-Leu-Leu-Glu-beta-naphthylamine-hydrolysing (peptidylglutamyl-peptide hydrolase) and N-Cbz-Leu-Leu-Leu-MCA-hydrolysing activities, whereas these activities are actually increased when the MCP is in its latent form. Hsp 90 protects against oxidative inactivation of the trypsin-like and N-Cbz-Leu-Leu-Leu-MCA-hydrolysing activities of the MCP active form, and alpha-crystallin protects the trypsin-like activity. The specificity of the Hsp 90-mediated protection was assessed by a quantitative analysis of the two-dimensional electrophoretic pattern of MCP subunits before and after oxidation of the MCP, in the presence or absence of Hsp 90. Treatment of the FAO hepatoma cell line with iron and ascorbate was found to inactivate the MCP. Hsp 90 overexpression obtained by challenging the cells with iron was associated with a decreased susceptibility to oxidative inactivation of the MCP trypsin-like activity. Depletion of Hsp 90 by using antisense oligonucleotides resulted in an increased susceptibility to oxidative inactivation of the MCP trypsin-like activity, providing evidence for the physiological relevance of Hsp 90-mediated protection of the MCP. PMID:9657982

Protection from oxidative inactivation of the 20S proteasome by heat-shock protein 90.

PubMed

Conconi, M; Petropoulos, I; Emod, I; Turlin, E; Biville, F; Friguet, B

1998-07-15

Heat-shock protein 90 (Hsp 90) has been implicated in both protection against oxidative inactivation and inhibition of the multicatalytic proteinase (MCP, also known as 20 S proteasome). We report here that the protective and inhibitory effects of Hsp 90 depend on the activation state of the proteasome. Hsp 90 (and also alpha-crystallin) inhibits the N-Cbz-Leu-Leu-Leu-MCA-hydrolysing activity (Cbz=benzyloxycarbonyl; MCA=7-amido-4-methylcoumarin) when the rat liver MCP is in its latent form, but no inhibitory effects are observed when the MCP is in its active form. Metal-catalysed oxidation of the active MCP inactivates the Ala-Ala-Phe-MCA-hydrolysing (chymotrypsin-like), N-Boc-Leu-Ser-Thr-Arg-MCA-hydrolysing (trypsin-like; Boc=t-butyloxycarbonyl), N-Cbz-Leu-Leu-Glu-beta-naphthylamine-hydrolysing (peptidylglutamyl-peptide hydrolase) and N-Cbz-Leu-Leu-Leu-MCA-hydrolysing activities, whereas these activities are actually increased when the MCP is in its latent form. Hsp 90 protects against oxidative inactivation of the trypsin-like and N-Cbz-Leu-Leu-Leu-MCA-hydrolysing activities of the MCP active form, and alpha-crystallin protects the trypsin-like activity. The specificity of the Hsp 90-mediated protection was assessed by a quantitative analysis of the two-dimensional electrophoretic pattern of MCP subunits before and after oxidation of the MCP, in the presence or absence of Hsp 90. Treatment of the FAO hepatoma cell line with iron and ascorbate was found to inactivate the MCP. Hsp 90 overexpression obtained by challenging the cells with iron was associated with a decreased susceptibility to oxidative inactivation of the MCP trypsin-like activity. Depletion of Hsp 90 by using antisense oligonucleotides resulted in an increased susceptibility to oxidative inactivation of the MCP trypsin-like activity, providing evidence for the physiological relevance of Hsp 90-mediated protection of the MCP.

Role of specific activators of intestinal amino acid transport in Bombyx mori larval growth and nutrition.

PubMed

Leonardi, M G; Casartelli, M; Fiandra, L; Parenti, P; Giordana, B

2001-12-01

Nutrient absorption and its modulation are critical for animal growth. In this paper, we demonstrate that leucine methyl ester (Leu-OMe) can greatly increase the activity of the transport system responsible for the absorption of most essential amino acids in the larval midgut of the silkworm Bombyx mori. We investigated leucine uptake activation by Leu-OMe in brush border membrane vesicles and in the apical membrane of epithelial cells in the midgut incubated in vitro. Moreover, the addition of this strong activator of amino acid absorption to diet significantly affected larval growth. Silkworms fed on artificial diet supplemented with Leu-OMe reached maximum body weight 12-18 h before control larvae, and produced cocoon shells up to 20% heavier than those of controls. The activation of amino acid absorption plays an essential role in larval development so that larval growth and cocoon production similar to controls reared on an artificial diet with 25% of dry mulberry leaf powder were observed in silkworms fed on an artificial diet with only 5% of mulberry powder. Arch. Copyright 2001 Wiley-Liss, Inc.

The Hb A variant (beta73 Asp-->Leu) disrupts Hb S polymerization by a novel mechanism.

PubMed

Adachi, Kazuhiko; Ding, Min; Surrey, Saul; Rotter, Maria; Aprelev, Alexey; Zakharov, Mikhail; Weng, Weijun; Ferrone, Frank A

2006-09-22

Polymerization of a 1:1 mixture of hemoglobin S (Hb S) and the artificial mutant HbAbeta73Leu produces a dramatic morphological change in the polymer domains in 1.0 M phosphate buffer that are a characteristic feature of polymer formation. Instead of feathery domains with quasi 2-fold symmetry that characterize polymerization of Hb S and all previously known mixtures such as Hb A/S and Hb F/S mixtures, these domains are compact structures of quasi-spherical symmetry. Solubility of Hb S/Abeta73Leu mixtures was similar to that of Hb S/F mixtures. Kinetics of polymerization indicated that homogeneous nucleation rates of Hb S/Abeta73Leu mixtures were the same as those of Hb S/F mixtures, while exponential polymer growth (B) of Hb S/Abeta73Leu mixtures were about three times slower than those of Hb S/F mixtures. Differential interference contrast (DIC) image analysis also showed that fibers in the mixture appear to elongate between three and five times more slowly than in equivalent Hb S/F mixtures by direct measurements of exponential growth of mass of polymer in a domain. We propose that these results of Hb S/Abeta73Leu mixtures arise from a non-productive binding of the hybrid species of this mixture to the end of the growing polymer. This "cap" prohibits growth of polymers, but by nature is temporary, so that the net effect is a lowered growth rate of polymers. Such a cap is consistent with known features of the structure of the Hb S polymer. Domains would be more spherulitic because slower growth provides more opportunity for fiber bending to spread domains from their initial 2-fold symmetry. Moreover, since monomer depletion proceeds more slowly in this mixture, more homogeneous nucleation events occur, and the resulting gel has a far more granular character than normally seen in mixtures of non-polymerizing hemoglobins with Hb S. This mixture is likely to be less stiff than polymerized mixtures of other hybrids such as Hb S with HbF, potentially providing a novel approach to therapy.

All in the name of flavour, fragrance & freshness: Commonly used smokeless tobacco preparations in & around a tertiary hospital in India

PubMed Central

Dwivedi, Shridhar; Aggarwal, Amitesh; Dev, Munish

2012-01-01

Background & objectives: There is a general misconception that smokeless tobacco particularly sweetened and flavoured paan masala and gutkas are safe to use. The present study was undertaken with the objective of highlighting the deceptive and aggressive marketing techniques adopted by the manufacturers of smokeless tobacco preparations exploiting cultural, social and religious values. Another object was to highlight the lack of transparency in terms of content, weight, quality control and warning. Methods: All empty pouches of the used paan masalas, gutka, khaini or surti in and around a tertiary care hospital at east Delhi were collected. Their constituents were studied as per written declaration by the manufacturers on each packet. Information on net weight, cost, presence and type of warning, and quality assurance on each brand provided on side of the packets was noted. Results: A total of 1136 pouches of 33 brands/varieties were collected. Most of the gutka preparations contained tobacco, betel nut, unknown flavouring agents, undeclared spices and heavy metals. Warning regarding the harmful effect of tobacco was written in 90.9 per cent of brands with 81.8 per cent in English language only in minute font. Contents of the products were mentioned in 84.8 per cent of brands and only 27.3 per cent of those mentioned the net weight of the ingredients. Interpretation & conclusions: Seemingly ‘innocuous’ tobacco preparations in the form of paan masalas, gutka, khaini, surti or mouth fresheners contain various harmful substance like tobacco, betel nut, sugar coated fennel, saccharine, heavy metals like silver, unknown flavouring agents and undeclared spices in unknown quantities. Lack of transparency in terms of content, weight, quality control and warning is duping unsuspecting consumers. PMID:23287132

Design of specific peptide inhibitors of phospholipase A2: structure of a complex formed between Russell's viper phospholipase A2 and a designed peptide Leu-Ala-Ile-Tyr-Ser (LAIYS).

PubMed

Chandra, Vikas; Jasti, Jayasankar; Kaur, Punit; Dey, Sharmistha; Srinivasan, A; Betzel, Ch; Singh, T P

2002-10-01

Phospholipase A(2) (EC 3.1.1.4) is a key enzyme of the cascade mechanism involved in the production of proinflammatory compounds known as eicosanoids. The binding of phospholipase A(2) to membrane surfaces and the hydrolysis of phospholipids are thought to involve the formation of a hydrophobic channel into which a single substrate molecule diffuses before cleavage. In order to regulate the production of proinflammatory compounds, a specific peptide inhibitor of PLA(2), Leu-Ala-Ile-Tyr-Ser, has been designed. Phospholipase A(2) from Daboia russelli pulchella (DPLA(2)) and peptide Leu-Ala-Ile-Tyr-Ser (LAIYS) have been co-crystallized. The structure of the complex has been determined and refined to 2.0 A resolution. The structure contains two crystallographically independent molecules of DPLA(2), with one molecule of peptide specifically bound to one of them. The overall conformations of the two molecules are essentially similar except in three regions; namely, the calcium-binding loop including Trp31 (residues 25-34), the beta-wing consisting of two antiparallel beta-strands (residues 74-85) and the C-terminal region (residues 119-133). Of these, the most striking difference pertains to the orientation of Trp31 in the two molecules. The conformation of Trp31 in molecule A was suitable to allow the binding of peptide LAIYS, while that in molecule B prevented the entry of the ligand into the hydrophobic channel. The structure of the complex clearly showed that the OH group of Tyr of the inhibitor formed hydrogen bonds with both His48 N(delta1) and Asp49 O(delta1), while O(gamma)H of Ser was involved in a hydrogen bond with Trp31. Other peptide backbone atoms interact with protein through water molecules, while Leu, Ala and Ile form strong hydrophobic interactions with the residues of the hydrophobic channel.

Production of an aminoterminally truncated, stable type of bioactive mouse fibroblast growth factor 4 in Escherichia coli.

PubMed

Sugawara, Saiko; Ito, Toshihiko; Sato, Shiori; Sato, Yuki; Kasuga, Kano; Kojima, Ikuo; Kobayashi, Masayuki

2014-05-01

In mice, fibroblast growth factor 4 (Fgf4) is a crucial gene for the generation of trophectoderm, progenitor cells of the placenta. Therefore, exogenous FGF4 promotes the isolation and maintenance of trophoblast stem cells from preimplantation embryos. We previously produced a 6× histidine (His)-tagged, mouse FGF4 (Pro(31)-Leu(202)) without a secretory signal peptide at the amino-terminus, referred to as HismFGF4, in Escherichia coli. Here, we found that HismFGF4 was unstable, such as in phosphate-buffered saline. In these conditions, site-specific cleavage between Ser(50) and Leu(51) was identified. In order to generate stable mouse FGF4 derivatives, a 6× His-tagged mouse FGF4 (Leu(51)-Leu(202)), termed HismFGF4L, was expressed in E. coli. HismFGF4L could be purified from the supernatant of cell lysates by heparin column chromatography. In phosphate-buffered saline, HismFGF4L was relatively stable. HismFGF4L exerted significant mitogenic activities at concentrations as low as 0.01 nM (P < 0.01) in mouse embryonic fibroblast Balb/c 3T3 cells expressing FGF receptor 2. In the presence of PD173074, an FGF receptor inhibitor, the growth-promoting activity of HismFGF4L was abolished. Taken together, we suggest that aminoterminally truncated HismFGF4L is capable of promoting the proliferation of mouse-derived cells via an authentic FGF signaling pathway. We consider that HismFGF4L is useful as a derivative of mouse FGF4 protein for analyzing the effects of mouse FGF4 and for stimulating cell growth of mouse-derived cells, such as trophoblast stem cells. Our study provides a simple method for the production of a bioactive, stable mouse FGF4 derivative in E. coli. Copyright © 2013 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

76 FR 11569 - Hazardous Materials: Enhanced Enforcement Authority Procedures

Federal Register 2010, 2011, 2012, 2013, 2014

2011-03-02

... harm Americans would move those materials as hidden shipments. Accordingly, although the presence of... statutory authority is not limited to undeclared shipments. On a broader scale, Section 7118 promotes the... commerce, when those employees have an objectively reasonable and articulable belief that the shipment may...

Association of ghrelin Leu72Met polymorphism with type 2 diabetes mellitus in Chinese population.

PubMed

Liu, Jing; Liu, Jia; Tian, Li-min; Liu, Ju-xiang; Bing, Ya-jun; Zhang, Ji-ping; Wang, Yun-Fang; Zhang, Lu-yan

2012-08-10

Ghrelin, a novel endogenous ligand for the growth hormone secretagogue receptor, is considered to implicate the development of the type 2 diabetes mellitus (T2DM). The Leu72Met (+408C>A) polymorphism of the preproghrelin, has been linked to obesity, insulin resistance and diabetes. To investigate the distribution of ghrelin gene Leu72Met polymorphism and its association with the type 2 diabetes mellitus in Chinese population. We conducted a case-control study on 877 patients with T2DM and 864 controls, which were genotyped by the polymerase chain reaction (PCR) technique, denaturing high performance liquid chromatography (DHPLC) and DNA sequence analysis. Laboratory analyses were carried out in the hospital laboratory. No significant difference in the Leu72Met genotype distributions and allele frequency was observed between type 2 diabetes mellitus and controls (both P>0.05). The polymorphism was not associated with T2DM. However, among the T2DM group, the patients carrying Leu72Leu genotype had significantly increased levels of FPG and serum creatinine compared with variant genotypes (Leu72Met and Met72Met) (P<0.05). In the control group, the subjects with variant genotypes had significantly increased levels of FINS, HOMA-IR compared with Leu72Leu genotype (P<0.05). The Leu72Met polymorphism of the preproghrelin gene was not associated with T2DM in Chinese population. However, it may have some roles in the etiology of insulin resistance. Copyright © 2012 Elsevier B.V. All rights reserved.

Associations of Leu72Met Polymorphism of Preproghrelin with Ratios of Plasma Lipids Are Diversified by a High-Carbohydrate Diet in Healthy Chinese Adolescents.

PubMed

Su, Mi; Qiu, Li; Wang, Qian; Jiang, Zhen; Liu, Xiao Juan; Lin, Jia; Fang, Ding Zhi

2015-01-01

The association of preproghrelin Leu72Met polymorphism with plasma lipids profile was inconsistently reported and needs more studies to be confirmed. Our study was to investigate the changes of plasma lipids ratios after a high-carbohydrate (high-CHO) diet in healthy Chinese adolescents with different genotypes of this polymorphism. Fifty-three healthy university students were given a washout diet of 54.1% carbohydrate for 7 days, followed by a high-CHO diet of 70.1% carbohydrate for 6 days. The anthropometric and biological parameters were analyzed at baseline and before and after the high-CHO diet. When compared with those before the high-CHO diet, body mass index (BMI) decreased in the male and female Met72 allele carriers. Decreased low-/high-density lipoprotein cholesterol (LDL-C/HDL-C) was observed in all participants except the female subjects with the Leu72Leu genotype. TG/HDL-C and log (TG/HDL-C) were increased only in the female subjects with the Leu72Leu genotype. These results suggest that the Met72 allele of preproghrelin Leu72Met polymorphism may be associated with decreased BMI induced by the high-CHO diet in male and female adolescents, while the Leu72 allele with increased TG/HDL-C and log (TG/HDL-C) in the female adolescents only. Furthermore, the decreasing effect of the high-CHO diet on LDL/HDL-C may be eliminated in the female Leu72Leu homozygotes. © 2015 S. Karger AG, Basel.

Yeast Mitochondrial Leucyl-tRNA Synthetase CP1 Domain Has Functionally Diverged to Accommodate RNA Splicing at Expense of Hydrolytic Editing*

PubMed Central

Sarkar, Jaya; Poruri, Kiranmai; Boniecki, Michal T.; McTavish, Katherine K.; Martinis, Susan A.

2012-01-01

The yeast mitochondrial leucyl-tRNA synthetase (ymLeuRS) performs dual essential roles in group I intron splicing and protein synthesis. A specific LeuRS domain called CP1 is responsible for clearing noncognate amino acids that are misactivated during aminoacylation. The ymLeuRS CP1 domain also plays a critical role in splicing. Herein, the ymLeuRS CP1 domain was isolated from the full-length enzyme and was active in RNA splicing in vitro. Unlike its Escherichia coli LeuRS CP1 domain counterpart, it failed to significantly hydrolyze misaminoacylated tRNALeu. In addition and in stark contrast to the yeast domain, the editing-active E. coli LeuRS CP1 domain failed to recapitulate the splicing activity of the full-length E. coli enzyme. Although LeuRS-dependent splicing activity is rooted in an ancient adaptation for its aminoacylation activity, these results suggest that the ymLeuRS has functionally diverged to confer a robust splicing activity. This adaptation could have come at some expense to the protein's housekeeping role in aminoacylation and editing. PMID:22383526

Transition Core Properties during Conversion of the NBSR from HEU to LEU Fuel

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hanson, A. L.; Diamond, D.

2013-10-31

The transition of the NBSR from HEU to LEU fuel is challenging due to reactivity constraints and the need to maintain an uninterrupted science program, the mission of the NBSR. The transition cannot occur with a full change of HEU to LEU fuel elements since the excess reactivity would be large enough that the NBSR would violate the technical specification for shutdown margin. Manufacturing LEU fuel elements to represent irradiated fuel elements would be cost prohibitive since 26 one-of-a-kind fuel elements would need to be manufactured. For this report a gradual transition from the present HEU fuel to the proposedmore » LEU fuel was studied. The gradual change approach would follow the present fuel management scheme and replace four HEU fuel elements with four LEU fuel elements each cycle. This manuscript reports the results of a series of calculations to predict the neutronic characteristics and how the neutronics will change during the transition from HEU to LEU in the NBSR.« less

[Molecular genetic analysis for a pedigree with severe hereditary coagulation factor VII deficiency].

PubMed

Ding, Qiu-lan; Wang, Hong-li; Wang, Xue-feng; Wang, Ming-shan; Fu, Qi-hua; Wu, Wen-man; Hu, Yi-qun; Wang, Zhen-yi

2003-10-01

To identify the genetic mutations of a severe inherited coagulation factor VII (FVII) deficiency pedigree. The diagnosis was validated by coagulant and haemostatic parameters. FVII gene mutations were screened in the propositus and his family members by DNA direct sequencing and confirmed by digestions of the restriction enzymes of the PCR production. Two heterozygous missense mutations were found in the propositus of the pedigree: a G to T transversion at position 9482 in exon 6 and a C to T mutation at position 11348 in exon 8 resulting in the amino acid substitution of Arg152 with Leu and Arg304 with Trp, respectively. A heterozygous single nucleotide deletion (C) at position 11487-11489(CCC) within exon 8 was identified, which predicted the frameshift mutation at position His351 followed by the changes of six corresponding amino acids and appearance of a premature protein caused by stop codon. The heterozygous mutations identified in the proband were derived from his father (Arg152 to Leu) and his mother (Arg304 to Trp mutation) and a heterozygous deletion (C) at position 11487-9(CCC). By tracing the other pedigree members, it was found that his grandmother had a heterozygous mutation of Arg304Trp and a heterozygous polymorphism of Arg353Gln and his grandfather had a heterozygous Arg152Leu mutation. Three heterozygous mutations were found in a pedigree with hereditary coagulation factor VII deficiency. Arg152Leu and deletion C at position 11487-9(CCC) were novel mutations.

Half-life of leu-enkephalin in the serum of infants of the first year of life on different types of feeding: relationship with temperament.

PubMed

Sokolov, O Yu; Kurasova, O B; Kost, N V; Gabaeva, M V; Korneeva, E V; Mikheeva, I G; Zozulya, A A

2004-04-01

The half-life of leu-enkephalin in the serum of infants aged under 1 year is significantly shorter than in adults. In girls leu-enkephalin half-life is significantly longer than in boys. The half-life of leu-enkephalin is different in infants on breast and formula feeding. Nine characteristics of temperament in infants of the first year of life were determined using EITQ and ITQ questionnaires. Serum leu-enkephalin half-life directly correlated with temperament characteristics (activity, perception, threshold), but not with the level psychomotor development.

Status and progress of the RERTR program in the year 2000.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Travelli, A.

2000-09-28

This paper describes the progress achieved by the Reduced Enrichment for Research and Test Reactors (RERTR) Program in collaboration with its many international partners during the year 2000 and discusses the main activities planned for the year 2001. The past year was characterized by important accomplishments and events for the RERTR program. Four additional shipments containing 503 spent fuel assemblies from foreign research reactors were accepted by the U.S. Altogether, 3,740 spent fuel assemblies from foreign research reactors have been received by the U.S. under the acceptance policy. Postirradiation examinations of three batches of microplates have continued to reveal excellentmore » irradiation behavior of U-MO dispersion fuels in a variety of compositions and irradiating conditions. h-radiation of two new batches of miniplates of greater sizes is in progress in the ATR to investigate me swelling behavior of these fuels under prototypic conditions. These materials hold the promise of achieving the program goal of developing LEU research reactor fuels with uranium densities in the 8-9 g /cm{sup 3} range. Qualification of the U-MO dispersion fuels is proceeding on schedule. Test fuel elements with 6 gU/cm{sup 3} are being fabricated by BWXT and are scheduled to begin undergoing irradiation in the HFR-Petten in the spring of 2001, with a goal of qualifying this fuel by the end of 2003. U-Mo with 8-9 gU/cm{sup 3} is planned to be qualified by the end of 2005. Joint LEU conversion feasibility studies were completed for HFR-Petten and for SAFARI-1. Significant improvements were made in the design of LEU metal-foil annular targets that would allow efficient production of fission {sup 99}Mo. Irradiations in the RAS-GAS reactor showed that these targets can formed from aluminum tubes, and that the yield and purity of their product from the acidic process were at least as good as those from the HEU Cintichem targets. Progress was made on irradiation testing of LEU UO{sub 2} dispersion fuel and on LEU conversion feasibility studies in the Russian RERTR program. Conversion of the BER-11reactor in Berlin, Germany, was completed and conversion of the La Reins reactor in Santiago, Chile, began. These are exciting times for the program. In the fuel development area, the RERTR program is aggressively pursuing qualification of high-density LEU U-Mo dispersion fuels, with the dual goal of enabling fi.uther conversions and of developing a substitute for LEU silicide fuels that can be more easily disposed of after expiration of the FRR SNF Acceptance Program. The {sup 99}Mo effort has reached the point where it appears feasible for all the {sup 99}Mo producers of the world to agree jointly to a common course of action leading to the elimination of HEU use in their processes. As in the past, the success of the RERTR program will depend on the international friendship and cooperation that has always been its trademark.« less

[D-Leu-4]-OB3 and MA-[D-Leu-4]-OB3, small molecule synthetic peptide leptin mimetics, improve glycemic control in diet-induced obese (DIO) mice.

PubMed

Wang, Anke; Anderson, Brian M; Novakovic, Zachary M; Grasso, Patricia

2018-03-01

We have previously shown that following oral delivery in dodecyl maltoside (DDM), [D-Leu-4]-OB3 and its myristic acid conjugate, MA-[D-Leu-4]-OB3, improved energy balance and glucose homeostasis in genetically obese/diabetic mouse models. More recently, we have provided immunohistochemical evidence indicating that these synthetic peptide leptin mimetics cross the blood-brain barrier and concentrate in the area of the arcuate nucleus of the hypothalamus in normal C57BL/6J and Swiss Webster mice, in genetically obese ob/ob mice, and in diet-induced obese (DIO) mice. In the present study, we describe the effects of oral delivery of [D-Leu-4]-OB3 and MA-[D-Leu-4]-OB3 on glycemic control in diet-induced (DIO) mice, a non-genetic rodent model of obesity and its associated insulin resistance, which more closely recapitulates common obesity and diabetes in humans. Male C57BL/6J and DIO mice, 17, 20, and 28 weeks of age, were maintained on a low-fat or high-fat diet and given vehicle (DDM) alone or [D-Leu-4]-OB3 or MA-[D-Leu-4]-OB3 in DDM by oral gavage for 12 or 14 days. Body weight gain, food and water intake, fasting blood glucose, oral glucose tolerance, and serum insulin levels were measured. Our data indicate that (1) [D-Leu-4]-OB3 and MA-[D-Leu-4]-OB3 restore glucose tolerance in male DIO mice maintained on a high-fat diet to levels comparable to those of non-obese C57BL/6J wild-type mice of the same age and sex maintained on a low-fat diet; and (2) the influence of [D-Leu-4]-OB3 and MA-[D-Leu-4]-OB3 on glycemic control appears to be independent of their effects on energy balance. These results suggest that [D-Leu-4]-OB3 and/or MA-[D-Leu-4]-OB3 may have application to the management of the majority of cases of common obesity in humans, a state characterized at least in part, by leptin resistance resulting from a defect in leptin transport across the blood-brain barrier. They further suggest that these small molecule synthetic peptide leptin mimetics, through their influence on glycemic control, may prevent the pre-diabetic state associated with most cases of common obesity from escalating into overt type 2 diabetes mellitus. Copyright © 2017 Elsevier Inc. All rights reserved.

Oral delivery of [D-Leu-4]-OB3 and MA-[D-Leu-4]-OB3, synthetic peptide leptin mimetics: Immunofluorescent localization in the mouse hypothalamus.

PubMed

Anderson, Brian M; Jacobson, Lauren; Novakovic, Zachary M; Grasso, Patricia

2017-06-01

This study describes the localization of [D-Leu-4]-OB3 and MA-[D-Leu-4]-OB3, synthetic peptide leptin mimetics, in the hypothalamus of Swiss Webster and C57BL/6J wild-type mice, leptin-deficient ob/ob mice, and leptin-resistant diet-induced obese (DIO) mice. The mice were given [D-Leu-4]-OB3 or MA-[D-Leu-4]-OB3 in 0.3% dodecyl maltoside by oral gavage. Once peak serum concentrations were reached, the mice received a lethal dose of pentobarbital and were subjected to intracardiac perfusion fixation. The brains were excised, post-fixed in paraformaldehyde, and cryo-protected in sucrose. Free-floating frozen coronal sections were cut at 25-µm and processed for imaging by immunofluorescence microscopy. In all four strains of mice, dense staining was concentrated in the area of the median eminence, at the base and/or along the inner wall of the third ventricle, and in the brain parenchyma at the level of the arcuate nucleus. These results indicate that [D-Leu-4]-OB3 and MA-[D-Leu-4]-OB3 cross the blood-brain barrier and concentrate in an area of the hypothalamus known to regulate energy balance and glucose homeostasis. Most noteworthy is the localization of [D-Leu-4]-OB3 immunoreactivity within the hypothalamus of DIO mice via a conduit that is closed to leptin in this rodent model, and in most cases of human obesity. Together with our previous studies describing the effects of [D-Leu-4]-OB3 and MA-[D-Leu-4]-OB3 on energy balance, glucose regulation, and signal transduction pathway activation, these findings are consistent with a central mechanism of action for these synthetic peptide leptin mimetics, and suggest their potential usefulness in the management of leptin-resistant obesity and type 2 diabetes in humans. Copyright © 2017 Elsevier B.V. All rights reserved.

Transcription attenuation is the major mechanism by which the leu operon of Salmonella typhimurium is controlled.

PubMed

Searles, L L; Wessler, S R; Calvo, J M

1983-01-25

Three mutations, each causing constitutive expression of the Salmonella typhimurium leu operon, were cloned into phage vector lambda gt4 on EcoRI DNA fragments carrying all of that operon except for part of the promoter-distal last gene. Sequence analysis of DNA from these phage demonstrated that each contains a single base change in the leu attenuator. Transcription of mutant DNA in vitro resulted in transcription beyond the usual site of termination. The level of beta-IPM dehydrogenase, the leuB enzyme, was elevated 40-fold in a strain carrying one of these mutations, and starvation of this strain for leucine had little effect on the amount of activity expressed. Using a strain with a wild-type promoter-leader region of the leu operon, the rates of synthesis and degradation of leu leader RNA and readthrough RNA (leu mRNA) were measured by DNA-RNA hybridizations with specific DNA probes. The rate of synthesis of the leu leader was about the same in cells grown with excess or with limiting leucine. On the other hand, the rate of synthesis of leu mRNA was 12-fold higher for cells grown in limiting leucine as opposed to excess leucine. The rate of degradation of these RNA species was the same under both conditions of growth. Thus, the variation in expression of the leu operon observed for cells grown in minimal medium is, for the most part, not caused by control over the frequency of initiation or by the differential stability of these RNA species. Rather, the variation is a direct result of the frequency of transcription termination at an attenuator site. These results taken together suggest that transcription attenuation is the major mechanism by which leucine regulates expression of the leu operon of S. typhimurium for cells growing in a minimal medium.

Undeclared Imports: Silent Borrowing in Educational Policy-Making and Research in Sweden

ERIC Educational Resources Information Center

Waldow, Florian

2009-01-01

Research on educational policy borrowing has mostly focused on explicit transfer processes, often highlighting how explicit reference to the international has served legitimatory purposes in the borrowing country. In contrast, this paper focuses on "silent" borrowing, i.e. non-acknowledged processes of policy transfer. The paper argues…

Psychopolitical Validity: Power, Culture, and Wellness

ERIC Educational Resources Information Center

Fisher, Adrian T.; Sonn, Christopher C.

2008-01-01

In this commentary, the authors review and critique Prilleltensky's model of psychopolitical validity and wellness. Although the overt recognition of power, oppression, and political forces are viewed most favorably, cautions are also given. Of most importance is the way in which his model is based in an undeclared North American model of…

Association of the Leu72Met polymorphism of the ghrelin gene with the risk of Type 2 diabetes in subjects with impaired glucose tolerance in the Finnish Diabetes Prevention Study.

PubMed

Mager, U; Lindi, V; Lindström, J; Eriksson, J G; Valle, T T; Hämäläinen, H; Ilanne-Parikka, P; Keinänen-Kiukaanniemi, S; Tuomilehto, J; Laakso, M; Pulkkinen, L; Uusitupa, M

2006-06-01

Ghrelin is a gut-brain regulatory peptide stimulating appetite and controlling energy balance. In previous studies, the Leu72Met polymorphism of the ghrelin gene has been associated with obesity and impaired insulin secretion. We investigated whether the Leu72Met polymorphism is associated with the incidence of Type 2 diabetes in subjects with impaired glucose tolerance (IGT) participating in the Finnish Diabetes Prevention Study (DPS). DPS was a longitudinal intervention study carried out in five participating centres in Finland. A total of 522 subjects with IGT were randomized into either an intervention or a control group and DNA was available from 507 subjects. The Leu72Met polymorphism was screened by the restriction fragment length polymorphism method. There were no differences in clinical and anthropometric characteristics among the genotypes at baseline. IGT subjects with the Met72 allele were at higher risk of developing Type 2 diabetes than subjects with the Leu72Leu genotype (P = 0.046). Our data also demonstrated that IGT subjects with the common Leu72Leu genotype developed Type 2 diabetes less frequently under intervention circumstances than subjects with the Met72 allele (OR = 0.28, 95% CI 0.10-0.79; P = 0.016). Subjects with the Leu72Leu genotype had a lower risk for the development of Type 2 diabetes. This was observed particularly in the study subjects who underwent an intensive diet and exercise intervention. Defective first-phase insulin secretion related to the Met72 allele might be one factor contributing to the conversion to Type 2 diabetes.

A molecular dynamics simulation study of amino acid selectivity of LeuRS editing domain from Thermus thermophilus.

PubMed

Rayevsky, Alexey; Sharifi, Mohsen; Tukalo, Michael

2018-06-18

The accuracy of protein synthesis is provided by the editing functions of aminoacyl-tRNA synthetases (aaRSs), a mechanism that eliminates misactivated amino acids or mischarged tRNAs. Despite research efforts, some molecular bases of these mechanisms are still unclear. The post-transfer editing pathway of leucyl-tRNA synthetase (LeuRS) carried out in a special insertion domain (the Connective Polypeptide 1 or CP1), as editing domain. Recently, it was shown by in vivo studies and was supported by mutagenesis, and the kinetics approaches that the CP1 domain of LeuRS has discriminatory power for different substrates. The goal of this work is to investigate the structural basis for amino acid recognition of LeuRS post-transfer editing processes with molecular dynamics (MD) simulation method. To pursue this aim, the molecular modeling studies on Thermus thermophiles LeuRS (LeuRSTT) with two post-transfer substrates (norvalyl-tRNA Leu and isoleucyl-tRNA Leu ) was performed. Our results revealed that post-transfer substrate norvalyl-tRNA Leu is more favorable. Moreover, the MD simulations show that branched side chain of Ile-A76 cannot allow water molecules to get close, which leads to a significant decrease in the rate of hydrolysis. Finally, the study showed that site mutation Asp347Ala has elucidated a number of fine structural differences in the binding mode of two post-transfer substrates to the active centre of LeuRS editing domain and two conserved threonines, namely Thr247 and Thr248, are responsible for the amino acid selection through the interaction with substrates. Copyright © 2018 Elsevier Inc. All rights reserved.

High-Fidelity Modelng and Simulation for a High Flux Isotope Reactor Low-Enriched Uranium Core Design

DOE PAGES

Betzler, Benjamin R.; Chandler, David; Davidson, Eva E.; ...

2017-05-08

A high-fidelity model of the High Flux Isotope Reactor (HFIR) with a low-enriched uranium (LEU) fuel design and a representative experiment loading has been developed to serve as a new reference model for LEU conversion studies. With the exception of the fuel elements, this HFIR LEU model is completely consistent with the current highly enriched uranium HFIR model. Results obtained with the new LEU model provide a baseline for analysis of alternate LEU fuel designs and further optimization studies. The newly developed HFIR LEU model has an explicit representation of the HFIR-specific involute fuel plate geometry, including the within-plate fuelmore » meat contouring, and a detailed geometry model of the fuel element side plates. Such high-fidelity models are necessary to accurately account for the self-shielding from 238U and the depletion of absorber materials present in the side plates. In addition, a method was developed to account for fuel swelling in the high-density LEU fuel plates during the depletion simulation. In conclusion, calculated time-dependent metrics for the HFIR LEU model include fission rate and cumulative fission density distributions, flux and reaction rates for relevant experiment locations, point kinetics data, and reactivity coefficients.« less

High-Fidelity Modelng and Simulation for a High Flux Isotope Reactor Low-Enriched Uranium Core Design

DOE Office of Scientific and Technical Information (OSTI.GOV)

Betzler, Benjamin R.; Chandler, David; Davidson, Eva E.

A high-fidelity model of the High Flux Isotope Reactor (HFIR) with a low-enriched uranium (LEU) fuel design and a representative experiment loading has been developed to serve as a new reference model for LEU conversion studies. With the exception of the fuel elements, this HFIR LEU model is completely consistent with the current highly enriched uranium HFIR model. Results obtained with the new LEU model provide a baseline for analysis of alternate LEU fuel designs and further optimization studies. The newly developed HFIR LEU model has an explicit representation of the HFIR-specific involute fuel plate geometry, including the within-plate fuelmore » meat contouring, and a detailed geometry model of the fuel element side plates. Such high-fidelity models are necessary to accurately account for the self-shielding from 238U and the depletion of absorber materials present in the side plates. In addition, a method was developed to account for fuel swelling in the high-density LEU fuel plates during the depletion simulation. In conclusion, calculated time-dependent metrics for the HFIR LEU model include fission rate and cumulative fission density distributions, flux and reaction rates for relevant experiment locations, point kinetics data, and reactivity coefficients.« less

Ecdysteroid-containing food supplements from Cyanotis arachnoidea on the European market: evidence for spinach product counterfeiting

NASA Astrophysics Data System (ADS)

Hunyadi, Attila; Herke, Ibolya; Lengyel, Katalin; Báthori, Mária; Kele, Zoltán; Simon, András; Tóth, Gábor; Szendrei, Kálmán

2016-12-01

Phytoecdysteroids like 20-hydroxyecdysone (“ecdysterone”) can exert a mild, non-hormonal anabolic/adaptogenic activity in mammals, and as such, are frequently used in food supplements. Spinach is well-known for its relatively low ecdysteroid content. Cyanotis arachnoidea, a plant native in China, is among the richest sources of phytoecdysteroids, and extracts of this plant are marketed in tons per year amounts via the internet at highly competitive prices. Here we report the investigation of a series of food supplements produced in Germany and claimed to contain spinach extracts. Twelve ecdysteroids including two new compounds were isolated and utilized as marker compounds. A comparative analysis of the products with Cyanotis and spinach extracts provides evidence that they were manufactured from Cyanotis extracts instead of spinach as stated. Based on the chromatographic fingerprints, 20-hydroxyecdysone 2- and 3-acetate are suggested as diagnostic markers for related quality control. This case appears to represent an unusual type of dietary supplement counterfeiting: undeclared extracts from alternative plants would supposedly ‘guarantee’ product efficacy.

Serotonin syndrome following overdose of a non-prescription slimming product containing sibutramine: a case report.

PubMed

Lam, Pui Kin; Leung, K S; Wong, T W; Lee, H H C; Tang, M H Y; Mak, T W L

2012-04-01

Non-prescription slimming products are popular and can be easily purchased from the Internet. However, adulteration of these products with undeclared substances including prescription drugs is not uncommon. We report a case of serotonin syndrome after an overdose of a non-prescription product containing sibutramine. A 21-year-old woman presented with somnolence, sinus tachycardia, generalised increase in tone, hyper-reflexia and clonus more prominent in the lower limbs after an intentional overdose of a non-prescription slimming product obtained from the Internet. The product was later found to contain sibutramine and other substances such as animal thyroid tissues, caffeine and phenolphthalein. Quantitative analysis of patient's serum on presentation revealed a sibutramine concentration of 112 ng/mL, which far exceeded the reported peak serum concentration after a single oral dose of 15 mg (the maximum daily recommended dose). No other culpable agent was identified. The overall clinical presentation was compatible with serotonin syndrome associated with sibutramine overdose. The patient made a full recovery after supportive management. This case highlighted the health threat posed by non-prescription slimming products sold over the Internet. Sibutramine overdose can result in serotonin syndrome, as in overdose of other serotonergic agents. Early recognition and timely supportive treatment are essential to ensure a good clinical outcome.

No association of the neuropeptide Y (Leu7Pro) and ghrelin gene (Arg51Gln, Leu72Met, Gln90Leu) single nucleotide polymorphisms with eating disorders.

PubMed

Kindler, Jochen; Bailer, Ursula; de Zwaan, Martina; Fuchs, Karoline; Leisch, Friedrich; Grün, Bettina; Strnad, Alexandra; Stojanovic, Mirjana; Windisch, Julia; Lennkh-Wolfsberg, Claudia; El-Giamal, Nadja; Sieghart, Werner; Kasper, Siegfried; Aschauer, Harald

2011-06-01

Genetic factors likely contribute to the biological vulnerability of eating disorders. Case-control association study on one neuropeptide Y gene (Leu7Pro) polymorphism and three ghrelin gene (Arg51Gln, Leu72Met and Gln90Leu) polymorphisms. 114 eating disorder patients (46 with anorexia nervosa, 30 with bulimia nervosa, 38 with binge eating disorder) and 164 healthy controls were genotyped. No differences were detected between patients and controls for any of the four polymorphisms in allele frequency and genotype distribution (P > 0.05). Allele frequencies and genotypes had no significant influence on body mass index (P > 0.05) in eating disorder patients. Positive findings of former case-control studies of associations between ghrelin gene polymorphisms and eating disorders could not be replicated. Neuropeptide Y gene polymorphisms have not been investigated in eating disorders before.

The influence of experimental inflammation and axotomy on leucine enkephalin (leuENK) distribution in intramural nervous structures of the porcine descending colon.

PubMed

Gonkowski, Slawomir; Makowska, Krystyna; Calka, Jaroslaw

2018-05-24

The enteric nervous system (ENS), located in the intestinal wall and characterized by considerable independence from the central nervous system, consists of millions of cells. Enteric neurons control the majority of functions of the gastrointestinal tract using a wide range of substances, which are neuromediators and/or neuromodulators. One of them is leucine-enkephalin (leuENK), which belongs to the endogenous opioid family. It is known that opioids in the gastrointestinal tract have various functions, including visceral pain conduction, intestinal motility and secretion and immune processes, but many aspects of distribution and function of leuENK in the ENS, especially during pathological states, remain unknown. During this experiment, the distribution of leuENK - like immunoreactive (leuENK-LI) nervous structures using the immunofluorescence technique were studied in the porcine colon in physiological conditions, during chemically-induced inflammation and after axotomy. The study included the circular muscle layer, myenteric (MP), outer submucous (OSP) and inner submucous plexus (ISP) and the mucosal layer. In control animals, the number of leuENK-LI neurons amounted to 4.86 ± 0.17%, 2.86 ± 0.28% and 1.07 ± 0.08% in the MP, OSP and ISP, respectively. Generally, both pathological stimuli caused an increase in the number of detected leuENK-LI cells, but the intensity of the observed changes depended on the factor studied and part of the ENS. The percentage of leuENK-LI perikarya amounted to 11.48 ± 0.96%, 8.71 ± 0.13% and 9.40 ± 0.76% during colitis, and 6.90 ± 0.52% 8.46 ± 12% and 4.48 ± 0.44% after axotomy in MP, OSP and ISP, respectively. Both processes also resulted in an increase in the number of leuENK-LI nerves in the circular muscle layer, whereas changes were less visible in the mucosa during inflammation and axotomy did not change the number of leuENK-LI mucosal fibers. LeuENK in the ENS takes part in intestinal regulatory processes not only in physiological conditions, but also under pathological factors. The observed changes are probably connected with the participation of leuENK in sensory and motor innervation and the neuroprotective effects of this substance. Differences in the number of leuENK-LI neurons during inflammation and after axotomy may suggest that the exact functions of leuENK probably depend on the type of pathological factor acting on the intestine.

Quantification and characterization of enkephalins in the upper part of the cat digestive tract and the coeliac ganglia.

PubMed

Julé, Y; Cupo, A; Niel, J P; Miolan, J P; Jarry, T

1988-07-01

The [Met]enkephalin, [Leu]enkephalin and [Met]enkephalin-arg-gly-leu contents of the upper part of the digestive tract (lower oesophageal sphincter, fundus, antrum, pylorus, duodenum, ileum) and coeliac ganglia of the cat were determined and identified. The enkephalin content of all the structures studied, expressed in femtomole/mg of wet tissue, was found to range from 83 to 446 with [Met]enkephalin; 19 to 63 with [Leu]enkephalin; 2.5 to 13 with [Met]enkephalin-arg-gly-leu. In the muscular and plexus layers the [Met]- and [Leu]enkephalin contents increase gradually from the lower oesophageal sphincter to the pylorus and then decrease from the duodenum to the ileum. The [Met]enkephalin versus [Leu]enkephalin ratio is 2.7 in the coeliac ganglia and ranges from 4.3 to 8.1 in the areas of the digestive tract investigated. In addition, the presence of authentic [Met]- and [Leu]enkephalin was confirmed in all the structures assayed by high pressure liquid chromatography. Owing to the low amounts of [Met]enkephalin-arg-gly-leu detected in individual samples of the coeliac ganglia and in the areas of the digestive tract investigated, it was not possible to characterize this peptide using high pressure liquid chromatography and therefore to confirm the presence of authentic [Met]enkephalin-arg-gly-leu in these structures. The differences in the enkephalin concentrations observed among these various areas of the digestive tract suggest that these peptides may act differently from one area to another, thus playing a complex integrative role in the nervous control of gastrointestinal tract motility.

Peptide-bacteria interactions using engineered surface-immobilized peptides from class IIa bacteriocins.

PubMed

Etayash, Hashem; Norman, Lana; Thundat, Thomas; Kaur, Kamaljit

2013-03-26

Specificity of the class IIa bacteriocin Leucocin A (LeuA), an antimicrobial peptide active against Gram-positive bacteria, including Listeria monocytogenes , is known to be dictated by the C-terminal amphipathic helical region, including the extended hairpin-like structure. However, its specificity when attached to a substrate has not been investigated. Exploiting properties of LeuA, we have synthesized two LeuA derivatives, which span the amphipathic helical region of the wild-type LeuA, consisting of 14- (14AA LeuA, CWGEAFSAGVHRLA) and 24-amino acid residues (24AA LeuA, CSVNWGEAFSAGVHRLANGGNGFW). The peptides were purified to >95% purity, as shown by analytical RP-HPLC and mass spectrometry. By including an N-terminal cysteine group, the tailored peptide fragments were readily immobilized at the gold interfaces. The resulting thickness and molecular orientation, determined by ellipsometry and grazing angle infrared spectroscopy, respectively, indicated that the peptides were covalently immobilized in a random helical orientation. The bacterial specificity of the anchored peptide fragments was tested against Gram-positive and Gram-negative bacteria. Our results showed that the adsorbed 14AA LeuA exhibited no specificity toward the bacterial strains, whereas the surface-immobilized 24AA LeuA displayed significant binding toward Gram-positive bacteria with various binding affinities from one strain to another. The 14AA LeuA did not show binding as this fragment is most likely too short in length for recognition by the membrane-bound receptor on the target bacterial cell membrane. These results support the potential use of class IIa bacteriocins as molecular recognition elements in biosensing platforms.

Neutronic study on conversion of SAFARI-1 to LEU silicide fuel

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ball, G.; Pond, R.; Hanan, N.

1995-02-01

This paper marks the initial study into the technical and economic feasibility of converting the SAFARI-1 reactor in South Africa to LEU silicide fuel. Several MTR assembly geometries and LEU uranium densities have been studied and compared with MEU and HEU fuels. Two factors of primary importance for conversion of SAFARI-1 to LEU fuel are the economy of the fuel cycle and the performance of the incore and excore irradiation positions.

Leu-9 (CD 7) positivity in acute leukemias: a marker of T-cell lineage?

PubMed

Ben-Ezra, J; Winberg, C D; Wu, A; Rappaport, H

1987-01-01

Monoclonal antibody Leu-9 (CD 7) has been reported to be a sensitive and specific marker for T-cell lineage in leukemic processes, since it is positive in patients whose leukemic cells fail to express other T-cell antigens. To test whether Leu-9 is indeed specific for T-cell leukemias, we examined in detail 10 cases of acute leukemia in which reactions were positive for Leu-9 and negative for other T-cell-associated markers including T-11, Leu-1, T-3, and E-rosettes. Morphologically and cytochemically, 2 of these 10 leukemias were classified as lymphoblastic, 4 as myeloblastic, 2 as monoblastic, 1 as megakaryoblastic, and 1 as undifferentiated. The case of acute megakaryoblastic leukemia is the first reported case to be Leu-9 positive. None of the 10 were TdT positive. Of six cases (two monoblastic, one lymphoblastic, one myeloblastic, one megakaryoblastic, and one undifferentiated) in which we evaluated for DNA gene rearrangements, only one, a peroxidase-positive leukemia, showed a novel band on study of the T-cell-receptor beta-chain gene. We therefore conclude that Leu-9 is not a specific marker to T-cell lineage and that, in the absence of other supporting data, Leu-9 positivity should not be used as the sole basis of classifying an acute leukemia as being T-cell derived.

Enhanced activity of human serotonin transporter variants associated with autism.

PubMed

Prasad, Harish C; Steiner, Jennifer A; Sutcliffe, James S; Blakely, Randy D

2009-01-27

Rare, functional, non-synonymous variants in the human serotonin (5-hydroxytryptamine, 5-HT) transporter (hSERT) gene (SLC6A4) have been identified in both autism and obsessive-compulsive disorder (OCD). Within autism, rare hSERT coding variants associate with rigid-compulsive traits, suggesting both phenotypic overlap with OCD and a shared relationship with disrupted 5-HT signalling. Here, we document functional perturbations of three of these variants: Ile425Leu; Phe465Leu; and Leu550Val. In transiently transfected HeLa cells, the three variants confer a gain of 5-HT transport phenotype. Specifically, enhanced SERT activity was also observed in lymphoblastoid lines derived from mutation carriers. In contrast to previously characterized Gly56Ala, where increased transport activity derives from catalytic activation, the three novel variants exhibit elevated surface density as revealed through both surface antagonist-binding and biotinylation studies. Unlike Gly56Ala, mutants Ile425Leu, Phe465Leu and Leu550Val retain a capacity for acute PKG and p38 MAPK regulation. However, both Gly56Ala and Ile425Leu demonstrate markedly reduced sensitivity to PP2A antagonists, suggesting that deficits in trafficking and catalytic modulation may derive from a common basis in perturbed phosphatase regulation. When expressed stably from the same genomic locus in CHO cells, both Gly56Ala and Ile425Leu display catalytic activation, accompanied by a striking loss of SERT protein.

Undeclared Wars: The Packaging of a National Security Strategy for the 1990’s

DTIC Science & Technology

1994-04-01

regarding shared or separation of powers between the executive and legislature. The issue became less of which branch of government was going to approve... separation of powers " in using military force in non-traditional roles can be found in the Constitution, as articulated by the Founding Fathers. 56

15 CFR 784.1 - Complementary access: General information on the purpose of complementary access, affected...

Code of Federal Regulations, 2010 CFR

2010-01-01

... may be conducted, on a selective basis, to verify the absence of undeclared nuclear material and nuclear related activities at reportable uranium hard-rock mines and ore beneficiation plants (see § 783.1... OF INDUSTRY AND SECURITY, DEPARTMENT OF COMMERCE ADDITIONAL PROTOCOL REGULATIONS COMPLEMENTARY ACCESS...

Individuals infected with HIV possess antibodies against IL-2.

PubMed Central

Bost, K L; Hahn, B H; Saag, M S; Shaw, G M; Weigent, D A; Blalock, J E

1988-01-01

Studies are presented here which demonstrate that antibodies reacting with human interleukin-2 (IL-2) are present in the sera of patients infected with the human immunodeficiency virus (HIV). It is likely that these antibodies are present due to a homology between the HIV envelope protein and IL-2. The homologues are six amino acids in length corresponding to the carboxy terminus of gp41, Leu-Glu-Arg-Ile-Leu-Leu (LERILL), and residues 14-19 of secreted IL-2, Leu-Glu-His-Leu-Leu-Leu (LEHLLL). Thus, we questioned whether antibodies made against this HIV envelope peptide would cross-react with IL-2. Not only do a high percentage of the HIV-infected individuals tested here have antibodies against LERILL, but these antibodies cross-react with the IL-2 sequence, LEHLLL. Additional antigenic processing of IL-2 is suggested by the finding that epitopes other than this sixmer are also recognized by antibodies in patients' sera. Thus, these studies suggest a mechanism by which infection with HIV can induce a potentially suppressive autoimmune response. Specifically, antibodies against an HIV envelope peptide cross-react with an epitope in IL-2. PMID:2464543

AFRRI (Armed Forces Radiobiology Research Institute) Reports, July, August, September 1989.

DTIC Science & Technology

1989-11-01

ippticatnpusit Maged. ineintr -det ic tent rat’ J tier oit l 3 3, Bank ,. W J. Hisiiilig% and citinparati.e tirganilig% A te’. atlas 31-12. 11)𔄁...concentrations of Leu-Leu-OMe (Tbl 1). Mini- he euthanized on day 19 posttransplant due to an accidental, mal CFt ,-(NI growth was observed with 10’ Leu-leu...phospholipid which provides the arachidlonic acid required for syn- veilswtth rgana m baeealsteacvtdga- thesis of prostaglandins and other eicosanoids (1-5

Substrate-modulated unwinding of transmembrane helices in the NSS transporter LeuT.

PubMed

Merkle, Patrick S; Gotfryd, Kamil; Cuendet, Michel A; Leth-Espensen, Katrine Z; Gether, Ulrik; Loland, Claus J; Rand, Kasper D

2018-05-01

LeuT, a prokaryotic member of the neurotransmitter:sodium symporter (NSS) family, is an established structural model for mammalian NSS counterparts. We investigate the substrate translocation mechanism of LeuT by measuring the solution-phase structural dynamics of the transporter in distinct functional states by hydrogen/deuterium exchange mass spectrometry (HDX-MS). Our HDX-MS data pinpoint LeuT segments involved in substrate transport and reveal for the first time a comprehensive and detailed view of the dynamics associated with transition of the transporter between outward- and inward-facing configurations in a Na + - and K + -dependent manner. The results suggest that partial unwinding of transmembrane helices 1/5/6/7 drives LeuT from a substrate-bound, outward-facing occluded conformation toward an inward-facing open state. These hitherto unknown, large-scale conformational changes in functionally important transmembrane segments, observed for LeuT in detergent-solubilized form and when embedded in a native-like phospholipid bilayer, could be of physiological relevance for the translocation process.

Bioactivity of food peptides: biological response of rats to bovine milk whey peptides following acute exercise

PubMed Central

Moura, Carolina Soares; Lollo, Pablo Christiano Barboza; Morato, Priscila Neder; Risso, Eder Muller; Amaya-Farfan, Jaime

2017-01-01

ABSTRACT Background: Several physiologically beneficial effects of consuming a whey protein hydrolysate (WPH) have been attributed to the greater availability of bioactive peptides. Aims: The aim was to investigate the effect of four branched-chain amino acid- (BCAA-)containing dipeptides, present in WPH, on immune modulation, stimulation of HSP expression, muscle protein synthesis, glycogen content, satiety signals and the impact of these peptides on the plasma free amino acid profiles. Methods: The animals were divided in groups: control (rest, without gavage), vehicle (water), L-isoleucyl-L-leucine (lle-Leu), L-leucyl-L-isoleucine (Leu-lle), L-valyl-Lleucine (Val-Leu), L-leucyl-L-valine (Leu-Val) and WPH. All animals were submitted to acute exercise, except for control. Results: lle-Leu stimulated immune response, hepatic and muscle glycogen and HSP60 expression, whereas Leu-Val enhanced HSP90 expression. All dipeptides reduced glucagon-like peptide-1 and glucose-dependent insulinotropic polypeptide, no changes were observed on leptin. All peptides inhibited NF-kB expression. The plasma amino acid time-course showed peptide-specific and isomer-specific metabolic features, including increases of the BCAAs. Conclusion: The data indicate that lle-Leu was effective to attenuate immune-suppression exercise-induced, promoted glycogen content and stimulated anti-stress effect (HSP). Furthermore, Leu-Val increased HSP90, p-4EBP1, p-mTOR and p-AMPK expression. The data suggest the involvement of these peptides in various beneficial functions of WPH consumption. PMID:28326005

Enkephalins in the inferior mesenteric ganglion of the cat and in the area of the lower digestive tract innervated by this ganglion: quantification by radio-immunoassay and characterization by high pressure liquid chromatography.

PubMed

Cupo, A; Niel, J P; Miolan, J P; Jule, Y; Jarry, T

1988-01-01

Met-enkephalin, Leu-enkephalin and Met-enkephalin-Arg-Gly-Leu were quantified and characterized in the cat inferior mesenteric ganglion and in the area of the lower digestive tract innervated by this ganglion, including the proximal colon, distal colon and internal anal sphincter. In the structures studied, the concentrations of enkephalins expressed as femtomole/mg of wet tissue ranged from 66 to 160 with Met-enkephalin, from 15 to 45 with Leu-enkephalin and from 2 to 12 for Met-enkephalin-arg-gly-leu. In the lower digestive tract, the Met- and Leu-enkephalin content decreased from the proximal colon to the internal anal sphincter. The Met-enkephalin versus Leu-enkephalin ratio of the structures investigated were as follows: inferior mesenteric ganglion 3.2, proximal colon 4.4, distal colon 5, internal and sphincter 4.5. In individual samples of all the structures assayed the results of high pressure liquid chromatography (HPLC) analysis pointed to the presence of authentic Met- and Leu-enkephalin. HPLC analysis could not be carried out on Met-enkephalin-Arg-Gly-Leu due to the very low concentrations of this peptide in all the structures assayed. Our results, combined with those of previous immunohistochemical and physiological studies, support the idea that enkephalins are involved in the nervous control of the motility of the lower digestive tract.

Progress in Chile in the development of the fission {sup 99}Mo production using modified CINTICHEM

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schrader, R.; Klein, J.; Medel, J.

2008-07-15

Fission {sup 99}Mo will be produced in Chile irradiating low-enriched uranium (LEU) foil in a MTR research reactor. For the purpose of developing the capability to fabricate the target, which is done of uranium foil enclosed in swaged concentric aluminum tubes, dummy targets are being fabricated using 130 {mu}m copper foil instead of the uranium foil, wrapped in a 14{mu}m nickel fission-recoil barrier. Dummy targets using several dimensions of copper foil have been assembled; however, the emphasis is being set in targets fabricated using the dimensions of the LEU foil that KAERI will provide, i.e. 50 mm x 100mm xmore » 0.130 mm. The assembling of target using the last dimensions has not been free of difficulties. Neutronic calculations and preliminary thermal and fluid analyses were performed to estimate the fission products activity and the heat removal capability for a 13 grams LEU-foil annular target, which will be irradiated in the RECH-1 research reactor at the level power of 5 MW during 48 hours. In a fume hood, Cintichem processing of natural uranium shavings with the addition of different carriers were performed, obtaining recovery over 90% of the added Mo carrier. Expertise has been gained in (a) foil dissolution process in a dissolver locally designed, (b) in Mo precipitation process, and (c) preparation of the purification columns with AgC, C and HZrO. Additionally, the irradiated target cutting machine with an innovative design was finally assembled. (author)« less

31 CFR 540.308 - Low Enriched Uranium (LEU).

Code of Federal Regulations, 2014 CFR

2014-07-01

... 31 Money and Finance:Treasury 3 2014-07-01 2014-07-01 false Low Enriched Uranium (LEU). 540.308... OF FOREIGN ASSETS CONTROL, DEPARTMENT OF THE TREASURY HIGHLY ENRICHED URANIUM (HEU) AGREEMENT ASSETS CONTROL REGULATIONS General Definitions § 540.308 Low Enriched Uranium (LEU). The term low enriched...

31 CFR 540.308 - Low Enriched Uranium (LEU).

Code of Federal Regulations, 2011 CFR

2011-07-01

... 31 Money and Finance:Treasury 3 2011-07-01 2011-07-01 false Low Enriched Uranium (LEU). 540.308... OF FOREIGN ASSETS CONTROL, DEPARTMENT OF THE TREASURY HIGHLY ENRICHED URANIUM (HEU) AGREEMENT ASSETS CONTROL REGULATIONS General Definitions § 540.308 Low Enriched Uranium (LEU). The term low enriched...

31 CFR 540.308 - Low Enriched Uranium (LEU).

Code of Federal Regulations, 2012 CFR

2012-07-01

... 31 Money and Finance:Treasury 3 2012-07-01 2012-07-01 false Low Enriched Uranium (LEU). 540.308... OF FOREIGN ASSETS CONTROL, DEPARTMENT OF THE TREASURY HIGHLY ENRICHED URANIUM (HEU) AGREEMENT ASSETS CONTROL REGULATIONS General Definitions § 540.308 Low Enriched Uranium (LEU). The term low enriched...

31 CFR 540.308 - Low Enriched Uranium (LEU).

Code of Federal Regulations, 2013 CFR

2013-07-01

... 31 Money and Finance:Treasury 3 2013-07-01 2013-07-01 false Low Enriched Uranium (LEU). 540.308... OF FOREIGN ASSETS CONTROL, DEPARTMENT OF THE TREASURY HIGHLY ENRICHED URANIUM (HEU) AGREEMENT ASSETS CONTROL REGULATIONS General Definitions § 540.308 Low Enriched Uranium (LEU). The term low enriched...

31 CFR 540.308 - Low Enriched Uranium (LEU).

Code of Federal Regulations, 2010 CFR

2010-07-01

... 31 Money and Finance: Treasury 3 2010-07-01 2010-07-01 false Low Enriched Uranium (LEU). 540.308... OF FOREIGN ASSETS CONTROL, DEPARTMENT OF THE TREASURY HIGHLY ENRICHED URANIUM (HEU) AGREEMENT ASSETS CONTROL REGULATIONS General Definitions § 540.308 Low Enriched Uranium (LEU). The term low enriched...

Preproghrelin Leu72Met polymorphism is not associated with type 2 diabetes mellitus.

PubMed

Kim, Sun-Young; Jo, Dae-Sun; Hwang, Pyoung Han; Park, Ji Hyun; Park, Sung Kwang; Yi, Ho Keun; Lee, Dae-Yeol

2006-03-01

Ghrelin is a novel gut-brain peptide, which exerts somatotropic, orexigenic, and adipogenic effects. Genetic variants of ghrelin have been associated with both obesity and insulin metabolism. In this study, we determined a role of preproghrelin Leu72Met polymorphism on type 2 diabetes mellitus and its relationship to variables studied. Genotypes were assessed by polymerase chain reaction. Frequencies of the Leu72Met polymorphism were found to be 35.4% in the type 2 diabetic patients and 32.5% in the normal controls. The Leu72Met polymorphism was not associated with hypertension, macroangiopathy, retinopathy, serum cholesterol, triglyceride, blood urea nitrogen, HbA(1c), lipoprotein (a), fasting insulin, or 24-hour urinary protein levels in the type 2 diabetic group. However, the Leu72Met polymorphism was clearly associated with serum creatinine levels in the diabetic group, as the Met72 carriers exhibited lower serum creatinine levels than the Met72 noncarriers. Our data indicate that the preproghrelin Leu72Met polymorphism is not associated with type 2 diabetes mellitus. However, the Leu72Met polymorphism is associated with serum creatinine levels. These data suggest that Met72 carrier status may be a predictable marker for diabetic nephropathy or renal impairment in type 2 diabetes mellitus.

Leucine and valine supplementation of low-protein diets for broiler chickens from 21 to 42 days of age.

PubMed

Ospina-Rojas, I C; Murakami, A E; Duarte, C R A; Nascimento, G R; Garcia, E R M; Sakamoto, M I; Nunes, R V

2017-04-01

The objective of this study was to determine the requirements and interactions between the standardized ileal digestible (SID) Leu and Val levels in low-protein diets, and their effects on performance, serum characteristics, carcass yield and diameter of muscle fibers of broiler chickens from d 21 to 42 posthatch. A total of 1,500 21-day-old Cobb 500 male broiler chickens were distributed in a completely randomized design in a 5 × 5 factorial arrangement for a total of 25 treatments with 3 replicates of 20 birds each. Treatments consisted of 5 SID Leu levels (1.0, 1.2, 1.4, 1.6, or 1.8%) and 5 SID Val levels (0.52, 0.67, 0.82, 0.97, or 1.12%). At 42 d of age, there was interaction (P < 0.05) between the SID levels of Leu and Val on feed intake and weight gain. There was a quadratic effect (P < 0.05) of Leu and Val levels on feed conversion, with minimal point estimated at the levels of 1.19 and 0.86%, respectively. Dietary Leu supplementation reduced linearly (P < 0.05) serum concentrations of triglycerides and β-hydroxybutyrate. Dietary Leu increased (P ≤ 0.05) the fiber diameters of the pectoralis major muscle and breast yield at the levels of 1.24 and 1.13%, respectively, while the thigh yield was improved with the level of 0.71% Val. Abdominal fat decreased linearly (P < 0.05) with increasing levels of dietary Leu and Val. The SID Leu and Val levels needed to optimize weight gain and feed conversion in low-CP diets for broiler chickens from d 21 to 42 posthatch were estimated at 1.15 and 0.86%, and 1.19 and 0.86%, respectively. The supplementation of Leu and Val can reduce the abdominal fat deposition in birds fed low-CP diets during the grower phase. Leu and Val interactions can influence the performance but not the serum characteristics, carcass yield and diameter of muscle fibers of broilers fed low-protein diets. Therefore, it is necessary to consider the dietary Leu content to estimate the ideal level of Val in low-CP diets for optimum broiler performance. © 2016 Poultry Science Association Inc.

An Exploration of Undeclared Students' Expectations of Experiences for Faculty Interactions and Co-Curricular Involvement

ERIC Educational Resources Information Center

Kittendorf, Lorie Anne

2012-01-01

Student persistence and achievement are areas of significant concern for institutions of higher education. With national college graduation rates hovering in the 50% range, it is important for colleges and universities to understand which student characteristics and campus environments lead to greater success, as well as the expectations students…

Interest-Divergence and the Colour of Cutbacks: Race, Recession and the Undeclared War on Black Children

ERIC Educational Resources Information Center

Gillborn, David

2013-01-01

Drawing on Critical Race Theory (CRT) and illustrating with examples from the English system, the paper addresses the hidden racist dimension to contemporary education reforms and argues that this is a predictable and recurrent theme at times of economic crisis. Derrick Bell's concept of "interest-convergence" argues that moments of…

First observation of N-acetyl leucine and N-acetyl isoleucine in diabetic patient hair and quantitative analysis by UPLC-ESI-MS/MS.

PubMed

Min, Jun Zhe; Tomiyasu, Yuki; Morotomi, Takashi; Jiang, Ying-Zi; Li, Gao; Shi, Qing; Yu, Hai-Fu; Inoue, Koichi; Todoroki, Kenichiro; Toyo'oka, Toshimasa

2015-04-15

Type 2 diabetes patients (DP) have significantly higher plasma levels of valine, leucine, isoleucine and alanine than the controls. Specific amino acids may acutely and chronically regulate insulin secretion from the pancreatic β-cells. We recently identified a metabolic signature of N-acetyl leucine (Ac-Leu) that strongly predicts diabetes development in mice hair. The Ac-Leu appears to be a potential biomarker candidate related to diabetes. However, the determination of Ac-Leu in human hair has not been reported. We measured the Ac-Leu, and its structure is similar to N-acetyl isoleucine (Ac-Ile) in human hair by ultra-performance liquid chromatography (UPLC) with electrospray ionization tandem mass spectrometry (ESI-MS/MS). The developed method was applied to the determination of Ac-Leu and Ac-Ile in the hair of healthy volunteers (HV) and DP. Ac-Leu, Ac-Ile and N-acetyl norleucine (Ac-Nle, IS) were extracted from human hair samples by a micropulverized extraction procedure, then separated on a C18 column by isocratic elution of acetonitrile-0.1% formic acid in water:0.1% formic acid (14:86, vol./vol.). MRM using the fragmentation transitions of m/z 174.1→86.1 in the positive ESI mode was performed to quantify the N-acetyl leucine, N-acetyl isoleucine and IS. Ac-Leu, Ac-Ile and Ac-Nle in the human hair samples were completely separated by isocratic elution of a 5.0 min duration wash program using a reversed-phase column, and sensitively detected by LC-MS/MS in the ESI(+) MRM mode. The amounts of Ac-Leu and Ac-Ile in the hairs of HV and DP were determined. When comparing the concentrations between DP and those from HV, a statistically significant correlation was observed for the Ac-Leu (p<0.001) and Ac-Ile (p<0.01). The proposed method is useful for the determination of Ac-Leu and Ac-Ile in the hairs of DP and HV. Human hair may serve as a noninvasive biosample for the diagnosis of diabetes. Crown Copyright © 2015. Published by Elsevier B.V. All rights reserved.

Polymorphisms of the ghrelin/obestatin gene and ghrelin levels in Chinese children with short stature.

PubMed

Zou, Chao Chun; Huang, Ke; Liang, Li; Zhao, Zheng Yan

2008-07-01

To investigate the role of ghrelin and polymorphisms of ghrelin/obestatin gene in children with short stature. A total of 117 GH deficient (GHD) and 81 idiopathic short stature (ISS) children were studied. The controls consisted of 125 age and gender-matched healthy children. The Arg51Gln, Leu72Met and Gln90Leu polymorphisms were genotyped using MassArray and total plasma ghrelin was measured by radioimmunoassay. In this study, the frequency of the Arg51Gln polymorphism was very low (0% in controls and 1.0% in patients). The frequency of the Gln90Leu polymorphism was 1.6% in controls and 0.5% in patients, respectively. Higher frequencies of Leu72Met (34.4% in controls and 39.9% in patients) and Met72Met genotypes (4.0% in controls and 2.0% in patients) were found. The differences in the Arg51Gln, Leu72Met or Gln90Leu genotypes and allele frequencies between patients and controls were not significant. Also, there were no significant differences in the Leu72Met genotypes and allele frequencies between GHD and ISS subgroups. There were no significant differences in clinical characteristics and biochemistry markers (including ghrelin levels) among the different genotypes of Leu72Met. However, plasma ghrelin levels in the GHD group were significantly lower than those of controls (P = 0.001). These results suggest that ghrelin may have a role in GH secretion and controlling growth. Lower ghrelin levels, but not ghrelin/obestatin polymorphism, might contribute to GHD.

Factor XIII Val34Leu polymorphism and the risk of myocardial infarction under the age of 36 years.

PubMed

Rallidis, Loukianos S; Politou, Marianna; Komporozos, Christoforos; Panagiotakos, Demosthenes B; Belessi, Chrisoula I; Travlou, Anthi; Lekakis, John; Kremastinos, Dimitrios T

2008-06-01

There are limited and controversial data regarding the impact of factor XIII (FXIII) Val34Leu polymorphism in the pathogenesis of premature myocardial infarction (MI). We examined whether FXIII Val34Leu polymorphism is associated with the development of early MI. We recruited 159 consecutive patients who had survived their first acute MI under the age of 36 years (mean age = 32.1 +/- 3.6 years, 138 were men). The control group consisted of 121 healthy individuals matched with cases for age and sex, without a family history of premature coronary heart disease (CHD). FXIII Val34Leu polymorphism was tested with polymerase chain reaction and reverse hybridization. There was a lower prevalence of carriers of the Leu34 allele in patients than in controls (30.2 vs. 47.1%, p = 0.006). FXIII Val34Leu polymorphism was associated with lower risk for acute MI after adjusting for major cardiovascular risk factors (odds ratio [OR] = 0.51, 95% confidence interval [CI] 0.27-0.95, p = 0.03). Subgroup analysis according to angiographic findings ("normal" coronary arteries [n = 29] or significant CHD [n = 130]) showed that only patients with MI and significant CHD had lower prevalence of carriers of the Leu34 allele compared to controls after adjusting for major cardiovascular risk factors (OR = 0.42, 95% CI 0.22-0.83, p = 0.01). Our data indicate that FXIII Val34Leu polymorphism has a protective effect against the development of MI under the age of 36 years, particularly in the setting of significant CHD.

Uranium Anodic Dissolution under Slightly Alkaline Conditions Progress Report Full-Scale Demonstration with DU Foil

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gelis, A.; Brown, M. A.; Wiedmeyer, S.

2014-02-18

Argonne National Laboratory (Argonne) is developing an alternative method for digesting irradiated low enriched uranium (LEU) foil targets to produce 99Mo in neutral/alkaline media. This method consists of the electrolytic dissolution of irradiated uranium foil in sodium bicarbonate solution, followed by precipitation of base-insoluble fission and activation products, and uranyl-carbonate species with CaO. The addition of CaO is vital for the effective anion exchange separation of 99MoO 4 2- from the fission products, since most of the interfering anions (e.g., CO 3 2-) are removed from the solution, while molybdate remains in solution. An anion exchange is used to retainmore » and to purify the 99Mo from the filtrate. The electrochemical dissolver has been designed and fabricated in 304 stainless-steel (SS), and tested for the dissolution of a full-size depleted uranium (DU) target, wrapped in Al foil. Future work will include testing with low-burn-up DU foil at Argonne and later with high-burn-up LEU foils at Oak Ridge National Laboratory.« less

Leucine supplementation stimulates protein synthesis and reduces degradation signal activation in muscle of newborn pigs during acute endotoxemia

USDA-ARS?s Scientific Manuscript database

Sepsis disrupts skeletal muscle proteostasis and mitigates the anabolic response to leucine (Leu) in muscle of mature animals. We have shown that Leu stimulates muscle protein synthesis (PS) in healthy neonatal piglets. To determine if supplemental Leu can stimulate PS and reduce protein degradation...

Impairment of the Ubiquitin-Proteasome Pathway by Methyl N-(6-Phenylsulfanyl-1H-benzimidazol-2-yl)carbamate Leads to a Potent Cytotoxic Effect in Tumor Cells

PubMed Central

Dogra, Nilambra; Mukhopadhyay, Tapas

2012-01-01

In recent years, there has been a great deal of interest in proteasome inhibitors as a novel class of anticancer drugs. We report that fenbendazole (FZ) (methyl N-(6-phenylsulfanyl-1H-benzimidazol-2-yl)carbamate) exhibits a potent growth-inhibitory activity against cancer cell lines but not normal cells. We show here, using fluorogenic substrates, that FZ treatment leads to the inhibition of proteasomal activity in the cells. Succinyl-Leu-Leu-Val-Tyr-methylcoumarinamide (MCA), benzyloxycarbonyl-Leu-Leu-Glu-7-amido-4-MCA, and t-butoxycarbonyl-Gln-Ala-Arg-7-amido-4-MCA fluorescent derivatives were used to assess chymotrypsin-like, post-glutamyl peptidyl-hydrolyzing, and trypsin-like protease activities, respectively. Non-small cell lung cancer cells transiently transfected with an expression plasmid encoding pd1EGFP and treated with FZ showed an accumulation of the green fluorescent protein in the cells due to an increase in its half-life. A number of apoptosis regulatory proteins that are normally degraded by the ubiquitin-proteasome pathway like cyclins, p53, and IκBα were found to be accumulated in FZ-treated cells. In addition, FZ induced distinct ER stress-associated genes like GRP78, GADD153, ATF3, IRE1α, and NOXA in these cells. Thus, treatment of human NSCLC cells with fenbendazole induced endoplasmic reticulum stress, reactive oxygen species production, decreased mitochondrial membrane potential, and cytochrome c release that eventually led to cancer cell death. This is the first report to demonstrate the inhibition of proteasome function and induction of endoplasmic reticulum stress/reactive oxygen species-dependent apoptosis in human lung cancer cell lines by fenbendazole, which may represent a new class of anticancer agents showing selective toxicity against cancer cells. PMID:22745125

Isoleucine Biosynthesis in Leptospira interrogans Serotype lai Strain 56601 Proceeds via a Threonine-Independent Pathway† ‡

PubMed Central

Xu, Hai; Zhang, Yuzhen; Guo, Xiaokui; Ren, Shuangxi; Staempfli, Andreas A.; Chiao, Juishen; Jiang, Weihong; Zhao, Guoping

2004-01-01

Three leuA-like protein-coding sequences were identified in Leptospira interrogans. One of these, the cimA gene, was shown to encode citramalate synthase (EC 4.1.3.-). The other two encoded α-isopropylmalate synthase (EC 4.1.3.12). Expressed in Escherichia coli, the citramalate synthase was purified and characterized. Although its activity was relatively low, it was strictly specific for pyruvate as the keto acid substrate. Unlike the citramalate synthase of the thermophile Methanococcus jannaschii, the L. interrogans enzyme is temperature sensitive but exhibits a much lower Km (0.04 mM) for pyruvate. The reaction product was characterized as (R)-citramalate, and the proposed β-methyl-d-malate pathway was further confirmed by demonstrating that citraconate was the substrate for the following reaction. This alternative pathway for isoleucine biosynthesis from pyruvate was analyzed both in vitro by assays of leptospiral isopropylmalate isomerase (EC 4.2.1.33) and β-isopropylmalate dehydrogenase (EC 1.1.1.85) in E. coli extracts bearing the corresponding clones and in vivo by complementation of E. coli ilvA, leuC/D, and leuB mutants. Thus, the existence of a leucine-like pathway for isoleucine biosynthesis in L. interrogans under physiological conditions was unequivocally proven. Significant variations in either the enzymatic activities or mRNA levels of the cimA and leuA genes were detected in L. interrogans grown on minimal medium supplemented with different levels of the corresponding amino acids or in cells grown on serum-containing rich medium. The similarity of this metabolic pathway in leptospires and archaea is consistent with the evolutionarily primitive status of the eubacterial spirochetes. PMID:15292141

Effect of Leu-enkephalin and delta sleep inducing peptide (DSIP) on endogenous noradrenaline release by rat brain synaptosomes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lozhanets, V.V.; Anosov, A.K.

1986-01-01

The nonapeptide delta-sleep inducing peptide (DSIP) causes specific changes in the encephalogram of recipient animals: It prolongs the phase of long-wave or delta sleep. The cellular mechanism of action of DSIP has not yet been explained. To test the hyporhesis that this peptide or its degradation product may be presynaptic regulators of catecholamine release, the action of Leu-enkephaline, DSIP, and amino acids composing DSIP on release of endogenous noradrenalin (NA) from synaptosomes during depolarization was compared. Subcellular fractions from cerebral hemisphere of noninbred male albino rats were isolated. Lactate dehydrogenase activity was determined in the suspension of synaptosomes before andmore » after addition of 0.5% Triton X-100. The results were subjected to statistical analysis, using the Wilcoxon-Mann-Whitney nonparametric test.« less

Is there a tripeptidyl peptidase in the renal brush-border membrane?

PubMed Central

Kenny, A J; Ingram, J

1988-01-01

A recent claim that the renal brush border contains a tripeptidyl peptidase [Andersen & McDonald (1987) Am. J. Physiol. 253, F649-F655] was examined. In a fluorescent assay, the hydrolysis of Gly-Pro-Met-2-naphthylamide (-NH-Nap) and Gly-Pro-Leu-NH-Nap by pig kidney microvilli was strongly inhibited by amastatin or di-isopropyl phosphorofluoridate (inhibitors of aminopeptidases and dipeptidyl peptidase IV). The products formed were shown to be Gly-Pro and Met-NH-Nap (or Leu-NH-Nap) and free 2-naphthylamine. Specific antibodies to pig and rat aminopeptidase N abolished the apparent tripeptidyl peptidase activity. We conclude that these substrates are hydrolysed by the sequential attack of dipeptidyl peptidase IV and aminopeptidase N and that pig and rat brush borders lack a detectable tripeptidyl peptidase. Images Fig. 1. PMID:3058122

Undeclared Formaldehyde Levels in Patient Consumer Products: Formaldehyde Test Kit Utility.

PubMed

Ham, Jason E; Siegel, Paul; Maibach, Howard

2018-05-03

Formaldehyde allergic contact dermatitis (ACD) may be due to products with free formaldehyde or formaldehyde-releasing agents, however, assessment of formaldehyde levels in such products is infrequently conducted. The present study quantifies total releasable formaldehyde from "in-use" products associated with formaldehyde ACD and tests the utility of commercially available formaldehyde spot test kits. Personal care products from 2 patients with ACD to formaldehyde were initially screened at the clinic for formaldehyde using a formaldehyde spot test kit. Formaldehyde positive products were sent to the laboratory for confirmation by gas chromatography-mass spectrometry. In addition, 4 formaldehyde spot test kits were evaluated for potential utility in a clinical setting. Nine of the 10 formaldehyde spot test kit positive products obtained from formaldehyde allergic patients had formaldehyde with total releasable formaldehyde levels ranging from 5.4 to 269.4 µg/g. Of these, only 2 shampoos tested listed a formaldehyde-releasing agent in the ingredients or product literature. Subsequently, commercially available formaldehyde spot test kits were evaluated in the laboratory for ability to identify formaldehyde in personal care products. Chemical based formaldehyde spot test were more reliable than the enzymatic based test in identifying product releasable formaldehyde content. It is concluded that product labeled ingredient lists and available information are often inadequate to confirm the potential for formaldehyde exposure and chemical based spot test kits may have utility for identification of potential formaldehyde exposure from personal care products.

Low-enriched uranium high-density target project. Compendium report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Vandegrift, George; Brown, M. Alex; Jerden, James L.

2016-09-01

At present, most 99Mo is produced in research, test, or isotope production reactors by irradiation of highly enriched uranium targets. To achieve the denser form of uranium needed for switching from high to low enriched uranium (LEU), targets in the form of a metal foil (~125-150 µm thick) are being developed. The LEU High Density Target Project successfully demonstrated several iterations of an LEU-fission-based Mo-99 technology that has the potential to provide the world’s supply of Mo-99, should major producers choose to utilize the technology. Over 50 annular high density targets have been successfully tested, and the assembly and disassemblymore » of targets have been improved and optimized. Two target front-end processes (acidic and electrochemical) have been scaled up and demonstrated to allow for the high-density target technology to mate up to the existing producer technology for target processing. In the event that a new target processing line is started, the chemical processing of the targets is greatly simplified. Extensive modeling and safety analysis has been conducted, and the target has been qualified to be inserted into the High Flux Isotope Reactor, which is considered above and beyond the requirements for the typical use of this target due to high fluence and irradiation duration.« less

Production of antioxidant and ACE-inhibitory peptides from Kluyveromyces marxianus protein hydrolysates: Purification and molecular docking.

PubMed

Mirzaei, Mahta; Mirdamadi, Saeed; Ehsani, Mohamad Reza; Aminlari, Mahmoud

2018-04-01

Kluyveromyces marxianus protein hydrolysates were prepared by two different sonicated-enzymatic (trypsin and chymotrypsin) hydrolysis treatments to obtain antioxidant and ACE-inhibitory peptides. Trypsin and chymotrypsin hydrolysates obtained by 5 h, exhibited the highest antioxidant and ACE-inhibitory activities. After fractionation using ultrafiltration and reverse phase high performance liquid chromatography (RP-HPLC) techniques, two new peptides were identified. One fragment (LL-9, MW = 1180 Da) with the amino acid sequence of Leu-Pro-Glu-Ser-Val-His-Leu-Asp-Lys showed significant ACE inhibitory activity (IC 50  = 22.88 μM) while another peptide fragment (VL-9, MW = 1118 Da) with the amino acid sequence of Val-Leu-Ser-Thr-Ser-Phe-Pro-Pro-Lys showed the highest antioxidant and ACE inhibitory properties (IC 50  = 15.20 μM, 5568 μM TE/mg protein). The molecular docking studies revealed that the ACE inhibitory activities of VL-9 is due to interaction with the S2 (His513, His353, Glu281) and S'1 (Glu162) pockets of ACE and LL-9 can fit perfectly into the S1 (Thr345) and S2 (Tyr520, Lys511, Gln281) pockets of ACE. Copyright © 2017. Published by Elsevier B.V.

Investigation of TRPV1 loss-of-function phenotypes in TRPV1 Leu206Stop mice generated by N-ethyl-N-nitrosourea mutagenesis.

PubMed

Christoph, Thomas; Kögel, Babette; Schiene, Klaus; Peters, Thomas; Schröder, Wolfgang

2018-06-02

N-ethyl-N-nitrosourea (ENU) random mutagenesis was used to generate a mouse model for the analysis of the transient receptor potential vanilloid 1 (TRPV1) cation channel. A transversion from T→A in exon 4 led to a Leu206Stop mutation generating a loss-of-function mutant. The TRPV1 agonist capsaicin was used to analyze functional and nociceptive parameters in vitro and in vivo in TRPV1 Leu206Stop mice and congenic C3HeB/FeJ controls. Capsaicin-induced [Ca 2+ ] i changes in small diameter DRG neurons were significantly diminished in TRPV1 Leu206Stop mice and administration of capsaicin induced neither hypothermia nor nocifensive behaviour in vivo. TRPV1 Leu206Stop mice were tested in the spinal nerve ligation of mononeuropathic pain and developed mechanical hypersensitivity two weeks after nerve injury. In the open field test, a significant increase in spontaneous locomotion was detected in TRPV1 Leu206Stop mice as compared to wildtype controls. TRPV1 knockout mice have been reported to carry a similar phenotype regarding capsaicin-evoked responses in vitro and in vivo. However, in contrast to TRPV1 Leu206Stop mice, TRPV1 knockout mice did not differ in spontaneous locomotion as compared to congenic C57BL/6 mice, suggesting subtle ENU-dependent or independent strain differences between TRPV1 Leu206Stop mice and their wildtype controls. In summary, these data revealed a target-related (i.e. capsaicin-evoked) phenotype of TRPV1 Leu206Stop mice closely resembling that of published TRPV1 knockout mice. However, since ENU-mutant mice are congenic with the mouse strain initially used in random mutagenesis, direct phenotypic comparison with the respective wildtype controls is possible, and the time-consuming backcrossing in lines with targeted mutations is avoided. Copyright © 2018 Elsevier Inc. All rights reserved.

Unexpected combined effects of NADH dehydrogenase subunit-2 237 Leu/Met polymorphism and green tea consumption on renal function in male Japanese health check-up examinees: a cross-sectional study.

PubMed

Kokaze, Akatsuki; Ishikawa, Mamoru; Matsunaga, Naomi; Karita, Kanae; Yoshida, Masao; Ohtsu, Tadahiro; Ochiai, Hirotaka; Shirasawa, Takako; Nanri, Hinako; Hoshino, Hiromi; Takashima, Yutaka

2013-11-20

NADH dehydrogenase subunit-2 237 leucine/methionine (ND2-237 Leu/Met) polymorphism is associated with longevity in Japanese. A previous study has shown that ND2-237 Leu/Met polymorphism modulates the effects of green tea consumption on risk of hypertension. For men with ND2-237Leu, habitual green tea consumption may reduce the risk of hypertension. Moreover, there is a combined effect of ND2-237 Leu/Met polymorphism and alcohol consumption on risk of mildly decreased estimated glomerular filtration rate (eGFR) (<90 ml/min/1.73 m2). Several beneficial effects of green tea on the kidney have been reported. The objective of this study was to investigate whether ND2-237 Leu/Met polymorphism modifies the effects of green tea consumption on risk of mildly decreased eGFR in male Japanese health check-up examinees. For ND2-237Leu genotypic men, after adjustment for confounding factors, green tea consumption may increase the risk of mildly decreased eGFR (P for trend = 0.016). The adjusted odds ratio (OR) for mildly decreased eGFR was significantly higher in subjects with ND2-237Leu who consume ≥6 cups of green tea per day than those who consume ≤1 cup of green tea per day (adjusted OR = 5.647, 95% confidence interval: 1.528-20.88, P = 0.009). On the other hand, for ND2-237Met genotypic men, green tea consumption does not appear to determine the risk of mildly decreased eGFR. The present results suggest that ND2-237 Leu/Met polymorphism unexpectedly modifies the effects of green tea consumption on eGFR and the risk of mildly decreased eGFR in male Japanese subjects.

Unexpected combined effects of NADH dehydrogenase subunit-2 237 Leu/Met polymorphism and green tea consumption on renal function in male Japanese health check-up examinees: a cross-sectional study

PubMed Central

2013-01-01

Background NADH dehydrogenase subunit-2 237 leucine/methionine (ND2-237 Leu/Met) polymorphism is associated with longevity in Japanese. A previous study has shown that ND2-237 Leu/Met polymorphism modulates the effects of green tea consumption on risk of hypertension. For men with ND2-237Leu, habitual green tea consumption may reduce the risk of hypertension. Moreover, there is a combined effect of ND2-237 Leu/Met polymorphism and alcohol consumption on risk of mildly decreased estimated glomerular filtration rate (eGFR) (<90 ml/min/1.73 m2). Several beneficial effects of green tea on the kidney have been reported. The objective of this study was to investigate whether ND2-237 Leu/Met polymorphism modifies the effects of green tea consumption on risk of mildly decreased eGFR in male Japanese health check-up examinees. Results For ND2-237Leu genotypic men, after adjustment for confounding factors, green tea consumption may increase the risk of mildly decreased eGFR (P for trend = 0.016). The adjusted odds ratio (OR) for mildly decreased eGFR was significantly higher in subjects with ND2-237Leu who consume ≥6 cups of green tea per day than those who consume ≤1 cup of green tea per day (adjusted OR = 5.647, 95% confidence interval: 1.528-20.88, P = 0.009). On the other hand, for ND2-237Met genotypic men, green tea consumption does not appear to determine the risk of mildly decreased eGFR. Conclusion The present results suggest that ND2-237 Leu/Met polymorphism unexpectedly modifies the effects of green tea consumption on eGFR and the risk of mildly decreased eGFR in male Japanese subjects. PMID:24252463

Deletion of the Candida glabrata ERG3 and ERG11 genes: effect on cell viability, cell growth, sterol composition, and antifungal susceptibility.

PubMed Central

Geber, A; Hitchcock, C A; Swartz, J E; Pullen, F S; Marsden, K E; Kwon-Chung, K J; Bennett, J E

1995-01-01

We have cloned and sequenced the structural genes encoding the delta 5,6 sterol desaturase (ERG3 gene) and the 14 alpha-methyl sterol demethylase (ERG11 gene) from Candida glabrata L5 (leu2). Single and double mutants of these genes were created by gene deletion. The phenotypes of these mutants, including sterol profiles, aerobic viabilities, antifungal susceptibilities, and generation times, were studied. Strain L5D (erg3 delta::LEU2) accumulated mainly ergosta-7,22-dien-3 beta-ol, was aerobically viable, and remained susceptible to antifungal agents but had a slower generation time than its parent strain. L5LUD (LEU2 erg11 delta::URA3) strains required medium supplemented with ergosterol and an anaerobic environment for growth. A spontaneous aerobically viable mutant, L5LUD40R (LEU erg11 delta::URA3), obtained from L5LUD (LEU2 erg11 delta::URA3), was found to accumulate lanosterol and obtusifoliol, was resistant to azole antifungal agents, demonstrated some increase in resistance to amphotericin B, and exhibited a 1.86-fold increase in generation time in comparison with L5 (leu2). The double-deletion mutant L5DUD61 (erg3 delta::LEU2 erg11 delta::URA3) was aerobically viable, produced mainly 14 alpha-methyl fecosterol, and had the same antifungal susceptibility pattern as L5LUD40R (LEU2 erg11 delta::URA3), and its generation time was threefold greater than that of L5 (leu2). Northern (RNA) analysis revealed that the single-deletion mutants had a marked increase in message for the undeleted ERG3 and ERG11 genes. These results indicate that differences in antifungal susceptibilities and the restoration of aerobic viability exist between the C. glabrata ergosterol mutants created in this study and those sterol mutants with similar genetic lesions previously reported for Saccharomyces cerevisiae. PMID:8593007

L-Leucyl-L-Leucine Methyl Ester Treatment of Canine Marrow and Peripheral Blood Cells: Inhibition of Proliferative Responses with Maintenance of the Capacity for Autologous Marrow Engraftment

DTIC Science & Technology

1988-11-01

Copyright 0 198 by The Winiams & Wilkins Co. Printed in U.S.A. L-LEUCYL-L-LEUCINE METHYL ESTER TREATMENT OF CANINE MARROW AND PERIPHERAL BLOOD CELLS...Reearch CeThs eatetle, Washington 9%104 tInaiyuba on o canine UMrrowt and peripher hi Recently, Thiele and Lipsky have described adipeptide nionon clear...that marrow iincubation with Leu-Leu. Leu-Leu-OMe is a feasible method to deplete canine marrows of aloreactive and cytotoxic T cells prior to OMe

Efficient biosynthesis of L-phenylglycine by an engineered Escherichia coli with a tunable multi-enzyme-coordinate expression system.

PubMed

Liu, Qiaoli; Zhou, Junping; Yang, Taowei; Zhang, Xian; Xu, Meijuan; Rao, Zhiming

2018-03-01

Whole-cell catalysis with co-expression of two or more enzymes in a single host as a simple low-cost biosynthesis method has been widely studied and applied but hardly with regulation of multi-enzyme expression. Here we developed an efficient whole-cell catalyst for biosynthesis of L-phenylglycine (L-Phg) from benzoylformic acid through co-expression of leucine dehydrogenase from Bacillus cereus (BcLeuDH) and NAD + -dependent mutant formate dehydrogenase from Candida boidinii (CbFDH A10C ) in Escherichia coli with tunable multi-enzyme-coordinate expression system. By co-expressing one to four copies of CbFDH A10C and optimization of the RBS sequence of BcLeuDH in the expression system, the ratio of BcLeuDH to CbFDH in E. coli BL21/pETDuet-rbs 4 leudh-3fdh A10C was finally regulated to 2:1, which was the optimal one determined by enzyme-catalyzed synthesis. The catalyst activity of E. coli BL21/pETDuet-rbs 4 leudh-3fdh A10C was 28.4 mg L -1  min -1  g -1 dry cell weight for L-Phg production using whole-cell transformation, it's was 3.7 times higher than that of engineered E. coli without enzyme expression regulation. Under optimum conditions (pH 8.0 and 35 °C), 60 g L -1 benzoylformic acid was completely converted to pure chiral L-Phg in 4.5 h with 10 g L -1 dry cells and 50.4 g L -1 ammonium formate, and with enantiomeric excess > 99.9%. This multi-enzyme-coordinate expression system strategy significantly improved L-Phg productivity and demonstrated a novel low-cost method for enantiopure L-Phg production.

Replacement of two amino acids of 9R-dioxygenase-allene oxide synthase of Aspergillus niger inverts the chirality of the hydroperoxide and the allene oxide.

PubMed

Sooman, Linda; Wennman, Anneli; Hamberg, Mats; Hoffmann, Inga; Oliw, Ernst H

2016-02-01

The genome of Aspergillus niger codes for a fusion protein (EHA25900), which can be aligned with ~50% sequence identity to 9S-dioxygenase (DOX)-allene oxide synthase (AOS) of Fusarium oxysporum, homologues of the Fusarium and Colletotrichum complexes and with over 62% sequence identity to homologues of Aspergilli, including (DOX)-9R-AOS of Aspergillus terreus. The aims were to characterize the enzymatic activities of EHA25900 and to identify crucial amino acids for the stereospecificity. Recombinant EHA25900 oxidized 18:2n-6 sequentially to 9R-hydroperoxy-10(E),12(Z)-octadecadienoic acid (9R-HPODE) and to a 9R(10)-allene oxide. 9S- and 9R-DOX-AOS catalyze abstraction of the pro-R hydrogen at C-11, but the direction of oxygen insertion differs. A comparison between twelve 9-DOX domains of 9S- and 9R-DOX-AOS revealed conserved amino acid differences, which could contribute to the chirality of products. The Gly616Ile replacement of 9R-DOX-AOS (A. niger) increased the biosynthesis of 9S-HPODE and the 9S(10)-allene oxide, whereas the Phe627Leu replacement led to biosynthesis of 9S-HPODE and the 9S(10)-allene oxide as main products. The double mutant (Gly616Ile, Phe627Leu) formed over 90% of the 9S stereoisomer of HPODE. 9S-HPODE was formed by antarafacial hydrogen abstraction and oxygen insertion, i.e., the original H-abstraction was retained but the product chirality was altered. We conclude that 9R-DOX-AOS can be altered to 9S-DOX-AOS by replacement of two amino acids (Gly616Ile, Phe627Leu) in the DOX domain. Copyright © 2015 Elsevier B.V. All rights reserved.

Preproghrelin Leu72Met polymorphism predicts a lower rate of developing renal dysfunction in type 2 diabetic nephropathy.

PubMed

Lee, Dae-Yeol; Kim, Sun-Young; Jo, Dae-Sun; Hwang, Pyoung Han; Kang, Kyung Pyo; Lee, Sik; Kim, Won; Park, Sung Kwang

2006-07-01

Ghrelin is a novel peptide hormone, which exerts somatotropic, orexigenic and adipogenic effects. Recent studies have shown that the preproghrelin Leu72Met polymorphism is associated with serum creatinine (Scr) concentration in type 2 diabetes; 72Met carriers exhibited lower Scr levels as compared with the 72Met non-carriers. We hypothesized that the preproghrelin Leu72Met polymorphism is associated with a lower rate of developing renal dysfunction in patients with type 2 diabetic nephropathy. The preproghrelin Leu72Met polymorphism was investigated using PCR techniques in 138 patients with diabetic nephropathy divided into two groups, one with normal renal function and the other with renal dysfunction. Determination of the frequency of the preproghrelin Leu72Met polymorphism was the main outcome measure. The frequency of the Leu72Met polymorphism in diabetic nephropathy was significantly lower in patients with renal dysfunction (15.9%, P < 0.01) than in patients with normal renal function (42.0%) or in the diabetes control group (40.6%). The Leu72Met polymorphism was also associated with serum total cholesterol levels in diabetic nephropathy patients with renal dysfunction; the 72Met carriers had lower total cholesterol levels than the 72Met non-carriers (P < 0.05). These data suggest that 72Met carrier status may be used as a marker predicting a lower chance of developing renal dysfunction in diabetic nephropathy.

Isolation and structural elucidation of antioxidant peptides from oyster (Saccostrea cucullata) protein hydrolysate.

PubMed

Umayaparvathi, S; Meenakshi, S; Vimalraj, V; Arumugam, M; Balasubramanian, T

2014-01-01

Protein derived from the oyster (Saccostrea cucullata) was hydrolyzed using protease from Bacillus cereus SU12 for isolation of antioxidant peptides. The oyster hydrolysate exhibited a strong antioxidant potential in DPPH (85.7±0.37%) followed by Hydrogen peroxide radical scavenging activity (81.6±0.3%), Hydroxyl radical-scavenging activity (79.32±0.6%), Reducing power assay (2.63±0.2 OD at 700nm). Due to the high antioxidant potential, hydrolysate was fractionated in Sephadex G-25 gel filtration chromatography. The active peptide fraction was further purified by UPLC-MS. Totally 7 antioxidant peptides were collected. Among 7 peptides (SCAP 1-7), 3 peptides (SCAP 1, 3 and 7) had highest scavenging ability on DPPH radicals. The amino acid sequence and molecular mass of purified antioxidant peptides (SCAP1, SCAP3 and SCAP7) were determined by Q-TOF ESI mass spectroscopy and structures of the peptides were Leu-Ala-Asn-Ala-Lys (MW=515.29Da), Pro-Ser-Leu-Val-Gly-Arg-Pro-Pro-Val-Gly-Lys-Leu-Thr-Leu (MW=1432.89Da) and Val-Lys-Val-Leu-Leu-Glu-His-Pro-Val-Leu (MW=1145.75Da), respectively. The unique amino acid composition and sequence in the peptides might play an important role in expression of their antioxidant activity. The results of this study suggest that oyster protein hydrolysate is good source of natural antioxidants.

LeuX tRNA-dependent and -independent mechanisms of Escherichia coli pathogenesis in acute cystitis

PubMed Central

Hannan, Thomas J.; Mysorekar, Indira U.; Chen, Swaine L.; Walker, Jennifer N.; Jones, Jennifer M.; Pinkner, Jerome S.; Hultgren, Scott J.; Seed, Patrick C.

2013-01-01

Summary Uropathogenic Escherichia coli (UPEC) contain multiple horizontally acquired pathogenicity-associated islands (PAI) implicated in the pathogenesis of urinary tract infection. In a murine model of cystitis, type 1 pili-mediated bladder epithelial invasion and intracellular proliferation are key events associated with UPEC virulence. In this study, we examined the mechanisms by which a conserved PAI contributes to UPEC pathogenesis in acute cystitis. In the human UPEC strain UTI89, spontaneous excision of PAI IIUTI89 disrupts the adjacent leuX tRNA locus. Loss of wild-type leuX-encoded tRNA5Leu significantly delayed, but did not eliminate, FimB recombinase-mediated phase variation of type 1 pili. FimX, an additional FimB-like, leuX-independent recombinase, was also found to mediate type 1 pili phase variation. However, whereas FimX activity is relatively slow in vitro, it is rapid in vivo as a non-piliated strain lacking the other fim recombinases rapidly expressed type 1 pili upon experimental infection. Finally, we found that disruption of leuX, but not loss of PAI IIUTI89 genes, reduced bladder epithelial invasion and intracellular proliferation, independent of type 1 piliation. These findings indicate that the predominant mechanism for preservation of PAI IIUTI89 during the establishment of acute cystitis is maintenance of wild-type leuX, and not PAI IIUTI89 gene content. PMID:18036139

[D-Leu-4]-OB3, a synthetic peptide amide with leptin-like activity, augments the effects of orally delivered exenatide and pramlintide acetate on energy balance and glycemic control in insulin-resistant male C57BLK/6-m db/db mice.

PubMed

Leinung, Matthew C; Grasso, Patricia

2012-11-10

The escalation predicted for the incidence of both type 2 diabetes mellitus and obesity has prompted investigators to search for additional pharmacotherapeutic approaches to their treatment. Two of these approaches, combination pharmacotherapy and utilization of leptin-related bioactive synthetic peptides as anti-diabetes/anti-obesity agents, were used in the present study. Exenatide or pramlintide acetate was reconstituted in dodecyl maltoside (DDM) in the absence or presence of [D-Leu-4]-OB3, and delivered orally by gavage to insulin-resistant male C57BLK/6-m db/db mice twice daily for 14 days. Body weight gain, food and water intake, blood glucose, and serum insulin levels were measured. Mice given DDM alone for 14 days were 19.7% heavier than they were at the beginning of the study, while oral delivery of exenatide or [D-Leu-4]-OB3 in DDM reduced body weight gain to only 13.9% and 11.5%, respectively, of initial body weight. Mice receiving exenatide and [D-Leu-4]-OB3 were 4.2% lighter than they were at the beginning of the study. In another study, Intravail® treated control mice gained 38.2% of their initial body weight, while mice receiving pramlintide acetate or [D-Leu-4]-OB3 were only 26.8% and 25.4% heavier, respectively, at the end of the study, Co-administration of pramlintide acetate and [D-Leu-4]-OB3 did not further enhance the effect of pramlintide acetate on body weight gain. Food intake was reduced by exenatide, pramlintide acetate, and [D-Leu-4]-OB3 alone, and co-delivery with [D-Leu-4]-OB3 did not induce a further decrease. Water intake was not affected by exenatide, pramlintide acetate, or [D-Leu-4]-OB3 alone, but co-delivery of exenatide or pramlintide acetate with [D-Leu-4]-OB3 resulted in a significant reduction in water intake. Oral delivery of exenatide or pramlintide acetate in DDM significantly lowered blood glucose levels by 20.4% and 30.2%, respectively. Co-delivery with [D-Leu-4]-OB3 further reduced blood glucose by 38.3% and 50.5%, respectively. A concentration-dependent increase in serum insulin was observed in response to increasing concentrations of exenatide, and [D-Leu-4]-OB3 slightly reduced the insulin response to exenatide at all concentrations tested. Increasing concentrations of pramlintide acetate alone did not elevate serum insulin, and when given in combination with [D-Leu-4]-OB3, serum insulin levels fell below those of DDM-treated control mice. Our data indicate that (1) exenatide and pramlintide acetate, currently administered by subcutaneous injection, can be given orally in DDM; (2) the bioactivity of exenatide and pramlintide acetate is retained following oral delivery in DDM; and (3) the effects of exenatide and pramlintide acetate on energy balance and glycemic control can be enhanced by co-administration with [D-Leu-4]-OB3, a synthetic peptide amide with leptin-like activity. Copyright © 2012 Elsevier B.V. All rights reserved.

Regulation of the yjjQ-bglJ Operon, Encoding LuxR-Type Transcription Factors, and the Divergent yjjP Gene by H-NS and LeuO▿ †

PubMed Central

Stratmann, Thomas; Madhusudan, S.; Schnetz, Karin

2008-01-01

The yjjQ and bglJ genes encode LuxR-type transcription factors conserved in several enterobacterial species. YjjQ is a potential virulence factor in avian pathogenic Escherichia coli. BglJ counteracts the silencing of the bgl (β-glucoside) operon by H-NS in E. coli K-12. Here we show that yjjQ and bglJ form an operon carried by E. coli K-12, whose expression is repressed by the histone-like nucleoid structuring (H-NS) protein. The LysR-type transcription factor LeuO counteracts this repression. Furthermore, the yjjP gene, encoding a membrane protein of unknown function and located upstream in divergent orientation to the yjjQ-bglJ operon, is likewise repressed by H-NS. Mapping of the promoters as well as the H-NS and LeuO binding sites within the 555-bp intergenic region revealed that H-NS binds to the center of the AT-rich regulatory region and distal to the divergent promoters. LeuO sites map to the center and to positions distal to the yjjQ promoters, while one LeuO binding site overlaps with the divergent yjjP promoter. This latter LeuO site is required for full derepression of the yjjQ promoters. The arrangement of regulatory sites suggests that LeuO restructures the nucleoprotein complex formed by H-NS. Furthermore, the data support the conclusion that LeuO, whose expression is likewise repressed by H-NS and which is a virulence factor in Salmonella enterica, is a master regulator that among other loci, also controls the yjjQ-bglJ operon and thus indirectly the presumptive targets of YjjQ and BglJ. PMID:18055596

Auxotrophic recombinant Mycobacterium bovis BCG overexpressing Ag85B enhances cytotoxicity on superficial bladder cancer cells in vitro.

PubMed

Begnini, Karine Rech; Rizzi, Caroline; Campos, Vinicius Farias; Borsuk, Sibele; Schultze, Eduarda; Yurgel, Virginia Campello; Nedel, Fernanda; Dellagostin, Odir Antônio; Collares, Tiago; Seixas, Fabiana Kömmling

2013-02-01

BCG therapy remains at the forefront of immunotherapy for treating patients with superficial bladder cancer. The high incidence of local side effects and the presence of non-responder diseases have led to efforts to improve the therapy. Hence, we proposed that an auxotrophic recombinant BCG strain overexpressing Ag85B (BCG ∆leuD/Ag85B), could enhance the cytotoxicity to the human bladder carcinoma cell line 5637. The rBCG was generated using an expression plasmid encoding the mycobacterial antigen Ag85B to transform a BCG ∆leuD strain. The inhibitory effect of BCG ∆leuD/Ag85B on 5637 cells was determined by the MTT method, morphology observation and a LIVE/DEAD assay. Gene expression profiles for apoptotic, cell cycle-related and oxidative stress-related genes were investigated by qRT-PCR. Bax, bcl-2 and p53 induction by BCG ∆leuD/Ag85B treatment was evaluated by Western blotting. BCG ∆leuD/Ag85B revealed a superior cytotoxicity effect compared to the control strains used in this study. The results showed that the expression level of pro-apoptotic and cell cycle-related genes increased after BCG ∆leuD/Ag85B treatment, whereas the mRNA levels of anti-apoptotic genes decreased. Interestingly, BCG ∆leuD/Ag85B also increased the mRNA level of antioxidant enzymes in the bladder cancer cell line. Bax and p53 proteins levels increased following treatment. In conclusion, these results suggest that treatment with BCG ∆leuD/Ag85B enhances cytotoxicity for superficial bladder cancer cells in vitro. Therefore, rBCG therapy may have potential benefits in the treatment of bladder cancer.

Supplemental Reactor Physics Calculations and Analysis of ELF Mk 1A Fuel

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pope, Michael A.

2014-10-01

These calculations supplement previous the reactor physics work evaluating the Enhanced Low Enriched Uranium (LEU) Fuel (ELF) Mk 1A element. This includes various additional comparisons between the current Highly Enriched Uranium (HEU) and LEU along with further characterization of the performance of the ELF fuel. The excess reactivity to be held down at BOC for ELF Mk 1A fuel is estimated to be approximately $2.75 greater than with HEU for a typical cycle. This is a combined effect of the absence of burnable poison in the ELF fuel and the reduced neck shim worth in LEU fuel compared to HEU.more » Burnable poison rods were conceptualized for use in the small B positions containing Gd2O3 absorber. These were shown to provide $2.37 of negative reactivity at BOC and to burn out in less than half of a cycle. The worth of OSCCs is approximately the same between HEU and ELF Mk 1A (LEU) fuels in the representative loading evaluated. This was evaluated by rotating all banks simultaneously. The safety rod worth is relatively unchanged between HEU and ELF Mk 1A (LEU) fuels in the representative loading evaluated. However, this should be reevaluated with different loadings. Neutron flux, both total and fast (>1 MeV), is either the same or reduced upon changing from HEU to ELF Mk 1A (LEU) fuels in the representative loading evaluated. This is consistent with the well-established trend of lower neutron fluxes for a given power in LEU than HEU.The IPT loop void reactivity is approximately the same or less positive with ELF Mk 1A (LEU) fuel than HEU in the representative loading evaluated.« less

Novel Exenatide Analogs with Peptidic Albumin Binding Domains: Potent Anti-Diabetic Agents with Extended Duration of Action

PubMed Central

Levy, Odile E.; Jodka, Carolyn M.; Ren, Shijun Steven; Mamedova, Lala; Sharma, Abhinandini; Samant, Manoj; D’Souza, Lawrence J.; Soares, Christopher J.; Yuskin, Diane R.; Jin, Li Jenny; Parkes, David G.; Tatarkiewicz, Krystyna; Ghosh, Soumitra S.

2014-01-01

The design, synthesis and pharmacology of novel long-acting exenatide analogs for the treatment of metabolic diseases are described. These molecules display enhanced pharmacokinetic profile and potent glucoregulatory and weight lowering actions compared to native exenatide. [Leu14]exenatide-ABD is an 88 residue peptide amide incorporating an Albumin Binding Domain (ABD) scaffold. [Leu14]exenatide-ABP is a 53 residue peptide incorporating a short Albumin Binding Peptide (ABP). [Leu14]exenatide-ABD and [Leu14]exenatide-ABP exhibited nanomolar functional GLP-1 receptor potency and were metabolically stable in vitro in human plasma and in a pancreatic digestive enzyme mixture. Both molecules displayed picomolar and nanomolar binding association with albumin across multiple species and circulating half lives of 16 and 11 hours, respectively, post a single IV dose in rats. Unlike exenatide, both molecules elicited robust glucose lowering when injected 1 day prior to an oral glucose tolerance test, indicative of their extended duration of action. [Leu14]exenatide-ABD was compared to exenatide in a Lep ob/ob mouse model of diabetes. Twice-weekly subcutaneously dosed [Leu14]exenatide-ABD displayed superior glucose lowering and weight loss in diabetic mice when compared to continuously infused exenatide at the same total weekly dose. A single oral administration of each molecule via an enteric coated capsule to cynomolgus monkeys showed superior pharmacokinetics for [Leu14]exenatide-ABD as compared to [Leu14]exenatide-ABP with detectable exposure longer than 14 days. These studies support the potential use of these novel long acting exenatide analogs with different routes of administration for the treatment of type 2 diabetes. PMID:24503632

Novel consortium of Klebsiella variicola and Lactobacillus species enhances the functional potential of fermented dairy products by increasing the availability of branched-chain amino acids and the amount of distinctive volatiles.

PubMed

Rosales-Bravo, H; Morales-Torres, H C; Vázquez-Martínez, J; Molina-Torres, J; Olalde-Portugal, V; Partida-Martínez, L P

2017-11-01

Identify novel bacterial taxa that could increase the availability of branched-chain amino acids and the amount of distinctive volatiles during skim milk fermentation. We recovered 344 bacterial isolates from stool samples of healthy and breastfed infants. Five were selected based on their ability to produce branched-chain amino acids. Three strains were identified as Escherichia coli, one as Klebsiella pneumoniae and other as Klebsiella variicola by molecular and biochemical methods. HPLC and solid-phase microextraction with GC-MS were used for the determination of free amino acids and volatile compounds respectively. The consortium formed by K. variicola and four Lactobacillus species showed the highest production of Leu and Ile in skim milk fermentation. In addition, the production of volatile compounds, such as acetoin, ethanol, 2-nonanone, and acetic, hexanoic and octanoic acids, increased in comparison to commercial yogurt, Emmental and Gouda cheese. Also, distinctive volatiles, such as 2,3-butanediol, 4-methyl-2- hexanone and octanol, were identified. The use of K. variicola in combination with probiotic Lactobacillus species enhances the availability of Leu and Ile and the amount of distinctive volatiles during skim milk fermentation. The identified consortium increases the functional potential of fermented dairy products. © 2017 The Society for Applied Microbiology.

The RERTR Program : a status report.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Travelli, A.

1998-10-19

This paper describes the progress achieved by the Reduced Enrichment for Research and Test Reactors (RERTR) Program in collaboration with its many international partners since its inception in 1978. A brief summary of the results that the program had attained by the end of 1997 is followed by a detailed review of the major events, findings, and activities that took place in 1998. The past year was characterized by exceptionally important accomplishments and events for the RERTR program. Four additional shipments of spent fuel from foreign research reactors were accepted by the U.S. Altogether, 2,231 spent fuel assemblies from foreignmore » research reactors have been received by the U.S. under the acceptance policy. Fuel development activities began to yield solid results. Irradiations of the first two batches of microplates were completed. Preliminary postirradiation examinations of these microplates indicate excellent irradiation behavior of some of the fuel materials that were tested. These materials hold the promise of achieving the pro am goal of developing LEU research reactor fuels with uranium density in the 8-9 g /cm{sup 3} range. Progress was made in the Russian RERTR program, which aims to develop and demonstrate the technical means needed to convert Russian-supplied research reactors to LEU fuels. Feasibility studies for converting to LEU fuel four Russian-designed research reactors (IR-8 in Russia, Budapest research reactor in Hungary, MARIA in Poland, and WWR-SM in Uzbekistan) were completed. A new program activity began to study the feasibility of converting three Russian plutonium production reactors to the use of low-enriched U0{sub 2}-Al dispersion fuel, so that they can continue to produce heat and electricity without producing significant amounts of plutonium. The study of an alternative LEU core for the FRM-II design has been extended to address, with favorable results, the transient performance of the core under hypothetical accident conditions. A major milestone was accomplished in the development of a process to produce molybdenum-99 from fission targets utilizing LEU instead of HEU. Targets containing LEU metal foils were irradiated in the RAS-GAS reactor at BATAN, Indonesia, and molybdenum-99 was successfully extracted through the ensuing process. These are exciting times for the program and for all those involved in it, and last year's successes augur well for the future. However, as in the past, the success of the RERTR program will depend on the international friendship and cooperation that have always been its trademark.« less

X-ray diffraction studies of enkephalins. Crystal structure of [(4'-bromo) Phe4,Leu5]enkephalin.

PubMed Central

Ishida, T; Kenmotsu, M; Mino, Y; Inoue, M; Fujiwara, T; Tomita, K; Kimura, T; Sakakibara, S

1984-01-01

In order to investigate the structure-activity relationship of [Leu5]- and [Met5]enkephalins, [(4'-bromo)Phe4, Leu5]-, [(4'-bromo)Phe4, Met5]- and [Met5] enkephalins were synthesized and crystallized. The crystal structure of [(4'-bromo) Phe4, Leu5]- enkephalin was determined by X-ray diffraction method using the heavy atom method and refined to R = 0.092 by the least-squares method. The molecule in this crystal took essentially the same type I' beta-turn conformation found in [Leu5]enkephalin [Smith & Griffin (1978) Science 199, 1214-1216). On the other hand, the preliminary three-dimensional Patterson analyses showed that the most probable conformations of [(4'-bromo)Phe4,Met5]- and [Met5]enkephalins are both the dimeric extended forms. Based on these insights, the biologically active conformation of enkephalin was discussed in relation to the mu- and delta-receptors. PMID:6721829

Watershed Watch: The Importance of Mentors in Student-driven Full Inquiry Undergraduate Research Projects as the Foundation for an Introductory Course in Biogeoscience

NASA Astrophysics Data System (ADS)

Rock, B. N.; Hale, S. R.; Graham, K. J.; Hayden, L.; Barber, L.; Perry, C.; Schloss, J.; Sullivan, E.; Yuan, J.; Abebe, E.; Mitchell, L.; Abrams, E.; Gagnon, M.

2008-12-01

Watershed Watch (NSF 0525433) engages early undergraduate students from two-year and four-year colleges in student-driven full inquiry-based instruction in the biogeosciences. Program goals for Watershed Watch are to test if inquiry-rich student-driven projects sufficiently engage undeclared students (or noncommittal STEM majors) to declare a STEM major (or remain with their STEM major). A significant component of this program is an intensive two-week Summer course, in which undeclared freshmen research various aspects of a local watershed. Students develop their own research questions and study design, collect and analyze data, and produce a scientific or an oral poster presentation. The course objectives, curriculum and schedule are presented as a model for dissemination for other institutions and programs seeking to develop inquiry-rich courses designed to attract students into biogeoscience disciplines. Data from self-reported student feedback indicated the most important factors explaining high-levels of student motivation and research excellence in the course are 1) working with committed, energetic, and enthusiastic faculty mentors; and 2) faculty mentors demonstrating high degrees of teamwork and coordination.

Antibacterial effect of plasma rich in growth factors (PRGF®-Endoret®) against Staphylococcus aureus and Staphylococcus epidermidis strains.

PubMed

Anitua, E; Alonso, R; Girbau, C; Aguirre, J J; Muruzabal, F; Orive, G

2012-08-01

Formulations containing plasma rich in growth factors (PRGF) are opening new avenues in the field of regenerative medicine. To evaluate the potential antimicrobial effects of a product (plasma rich in growth factors; PRGF(®)-Endoret(®)) against both methicillin-sensitive and methicillin-resistant Staphylococcus aureus and Staphylococcus epidermidis. The potential effect of incorporating the patient's leucocytes into the PRGF formulation (F3+leu) was also studied. Blood samples were obtained from five healthy volunteers and used to prepare each type of PRGF (F1, F3 and F3+leu). Various biological assays were performed to compare the characteristics of the different formulations, including measurement of the concentration of platelets and leucocytes, and assays of coagulation. The microbiological activity of PRGF-Endoret against both staphylococcal strains was performed by counting the number of the surviving bacterial colonies after incubation at 0, 4 and 8 h with the different formulations. The three PRGF-Endoret formulations evaluated were enriched in platelets by 1.10, 2.57 and 1.89 times, respectively, and the leucocyte concentration in the F3+leu sample was increased by 3.9 times. We found that all formulations had a strong bacteriostatic effect, especially in the first 4 h after application. All formulations had an antibacterial effect at 4 h for three of the four strains, with the exception of methicillin-sensitive S. epidermidis. No differences in the bacterial inhibitory effect were found between the formulations. This is the first time different formulations of this product have been evaluated, and the results suggest that PRGF-Endoret could be used in the fight against postoperative and wound infections. © The Author(s). CED © 2012 British Association of Dermatologists.

Cocoa and Whey Protein Differentially Affect Markers of Lipid and Glucose Metabolism and Satiety.

PubMed

Campbell, Caroline L; Foegeding, E Allen; Harris, G Keith

2016-03-01

Food formulation with bioactive ingredients is a potential strategy to promote satiety and weight management. Whey proteins are high in leucine and are shown to decrease hunger ratings and increase satiety hormone levels; cocoa polyphenolics moderate glucose levels and slow digestion. This study examined the effects of cocoa and whey proteins on lipid and glucose metabolism and satiety in vitro and in a clinical trial. In vitro, 3T3-L1 preadipocytes were treated with 0.5-100 μg/mL cocoa polyphenolic extract (CPE) and/or 1-15 mM leucine (Leu) and assayed for lipid accumulation and leptin production. In vivo, a 6-week clinical trial consisted of nine panelists (age: 22.6 ± 1.7; BMI: 22.3 ± 2.1) consuming chocolate-protein beverages once per week, including placebo, whey protein isolate (WPI), low polyphenolic cocoa (LP), high polyphenolic cocoa (HP), LP-WPI, and HP-WPI. Measurements included blood glucose and adiponectin levels, and hunger ratings at baseline and 0.5-4.0 h following beverage consumption. At levels of 50 and 100 μg/mL, CPE significantly inhibited preadipocyte lipid accumulation by 35% and 50%, respectively, and by 22% and 36% when combined with 15 mM Leu. Leu treatment increased adipocyte leptin production by 26-37%. In the clinical trial, all beverages significantly moderated blood glucose levels 30 min postconsumption. WPI beverages elicited lowest peak glucose levels and HP levels were significantly lower than LP. The WPI and HP beverage treatments significantly increased adiponectin levels, but elicited no significant changes in hunger ratings. These trends suggest that combinations of WPI and cocoa polyphenols may improve markers of metabolic syndrome and satiety.

Production of LEU Fully Ceramic Microencapsulated Fuel for Irradiation Testing

DOE Office of Scientific and Technical Information (OSTI.GOV)

Terrani, Kurt A; Kiggans Jr, James O; McMurray, Jake W

2016-01-01

Fully Ceramic Microencapsulated (FCM) fuel consists of tristructural isotropic (TRISO) fuel particles embedded inside a SiC matrix. This fuel inherently possesses multiple barriers to fission product release, namely the various coating layers in the TRISO fuel particle as well as the dense SiC matrix that hosts these particles. This coupled with the excellent oxidation resistance of the SiC matrix and the SiC coating layer in the TRISO particle designate this concept as an accident tolerant fuel (ATF). The FCM fuel takes advantage of uranium nitride kernels instead of oxide or oxide-carbide kernels used in high temperature gas reactors to enhancemore » heavy metal loading in the highly moderated LWRs. Production of these kernels with appropriate density, coating layer development to produce UN TRISO particles, and consolidation of these particles inside a SiC matrix have been codified thanks to significant R&D supported by US DOE Fuel Cycle R&D program. Also, surrogate FCM pellets (pellets with zirconia instead of uranium-bearing kernels) have been neutron irradiated and the stability of the matrix and coating layer under LWR irradiation conditions have been established. Currently the focus is on production of LEU (7.3% U-235 enrichment) FCM pellets to be utilized for irradiation testing. The irradiation is planned at INL s Advanced Test Reactor (ATR). This is a critical step in development of this fuel concept to establish the ability of this fuel to retain fission products under prototypical irradiation conditions.« less

2007 international meeting on Reduced Enrichment for Research and Test Reactors (RERTR). Abstracts and available papers presented at the meeting

DOE Office of Scientific and Technical Information (OSTI.GOV)

NONE

2008-07-15

The Meeting papers discuss research and test reactor fuel performance, manufacturing and testing. Some of the main topics are: conversion from HEU to LEU in different reactors and corresponding problems and activities; flux performance and core lifetime analysis with HEU and LEU fuels; physics and safety characteristics; measurement of gamma field parameters in core with LEU fuel; nondestructive analysis of RERTR fuel; thermal hydraulic analysis; fuel interactions; transient analyses and thermal hydraulics for HEU and LEU cores; microstructure research reactor fuels; post irradiation analysis and performance; computer codes and other related problems.

Preproghrelin Leu72Met polymorphism in obese Korean children.

PubMed

Jo, Dae-Sun; Kim, Se-Lim; Kim, Sun-Young; Hwang, Pyoung Han; Lee, Kee-Hyoung; Lee, Dae-Yeol

2005-11-01

Ghrelin is a novel gut-brain peptide that has somatotropic, orexigenic, and adipogenic effects. We examined the preproghrelin Leu72Met polymorphism in 222 obese Korean children to determine whether it is associated with obesity. The frequencies of the Leu72Met polymorphism were 29.3% in obese, 32.3% in overweight, and 32.5% in lean Korean children. No significant difference was found between Met72 carrier and non-carrier obese children with respect to BMI, total body fat, serum triglycerides, total cholesterol, or LDL-cholesterol levels. Our data suggest that the preproghrelin Leu72Met polymorphism is not associated with obesity in children.

DLEU2 encodes an antisense RNA for the putative bicistronic RFP2/LEU5 gene in humans and mouse.

PubMed

Corcoran, Martin M; Hammarsund, Marianne; Zhu, Chaoyong; Lerner, Mikael; Kapanadze, Bagrat; Wilson, Bill; Larsson, Catharina; Forsberg, Lars; Ibbotson, Rachel E; Einhorn, Stefan; Oscier, David G; Grandér, Dan; Sangfelt, Olle

2004-08-01

Our group previously identified two novel genes, RFP2/LEU5 and DLEU2, within a 13q14.3 genomic region of loss seen in various malignancies. However, no specific inactivating mutations were found in these or other genes in the vicinity of the deletion, suggesting that a nonclassical tumor-suppressor mechanism may be involved. Here, we present data showing that the DLEU2 gene encodes a putative noncoding antisense RNA, with one exon directly overlapping the first exon of the RFP2/LEU5 gene in the opposite orientation. In addition, the RFP2/LEU5 transcript can be alternatively spliced to produce either several monocistronic transcripts or a putative bicistronic transcript encoding two separate open-reading frames, adding to the complexity of the locus. The finding that these gene structures are conserved in the mouse, including the putative bicistronic RFP2/LEU5 transcript as well as the antisense relationship with DLEU2, further underlines the significance of this unusual organization and suggests a biological function for DLEU2 in the regulation of RFP2/LEU5. Copyright 2004 Wiley-Liss, Inc.

The Leu72Met Polymorphism of the Prepro-ghrelin Gene is Associated With Alcohol Consumption and Subjective Responses to Alcohol: Preliminary Findings

PubMed Central

Suchankova, Petra; Yan, Jia; Schwandt, Melanie L.; Stangl, Bethany L.; Jerlhag, Elisabet; Engel, Jörgen A.; Hodgkinson, Colin A.; Ramchandani, Vijay A.; Leggio, Lorenzo

2017-01-01

Abstract Aims The orexigenic peptide ghrelin may enhance the incentive value of food-, drug- and alcohol-related rewards. Consistent with preclinical findings, human studies indicate a role of ghrelin in alcohol use disorders (AUD). In the present study an a priori hypothesis-driven analysis was conducted to investigate whether a Leu72Met missense polymorphism (rs696217) in the prepro-ghrelin gene (GHRL), is associated with AUD, alcohol consumption and subjective responses to alcohol. Method Association analysis was performed using the National Institute on Alcohol Abuse and Alcoholism (NIAAA) clinical sample, comprising AUD individuals and controls (N = 1127). Then, a post-hoc analysis using data from a human laboratory study of intravenous alcohol self-administration (IV-ASA, N = 144) was performed to investigate the association of this SNP with subjective responses following a fixed dose of alcohol (priming phase) and alcohol self-administration (ad libitum phase). Results The case-control study revealed a trend association (N = 1127, OR = 0.665, CI = 0.44–1.01, P = 0.056) between AUD diagnosis and Leu72Met. In AUD subjects, the SNP was associated with significantly lower average drinks per day (n = 567, β = −2.49, 95% CI = −4.34 to −0.64, P = 0.008) and significantly fewer heavy drinking days (n = 567, β = −12.00, 95% CI = −19.10 to −4.89, P < 0.001). The IV-ASA study further revealed that 72Met carriers had greater subjective responses to alcohol (P < 0.05) when compared to Leu72Leu both at priming and during ad lib self-administration. Conclusion Although preliminary, these findings suggest that the Leu72Leu genotype may lead to increased risk of AUD possibly via mechanisms involving a lower response to alcohol resulting in excessive alcohol consumption. Further investigations are warranted. Short Summary We investigated whether a Leu72Met missense polymorphism in the prepro-ghrelin gene, is associated with alcohol use disorder, alcohol consumption and subjective responses to alcohol. Although preliminary, results suggest that the Leu72Leu genotype may lead to increased risk of alcohol use disorder possibly via mechanisms involving a lower response to alcohol. PMID:28481975

The Leu72Met Polymorphism of the Prepro-ghrelin Gene is Associated With Alcohol Consumption and Subjective Responses to Alcohol: Preliminary Findings.

PubMed

Suchankova, Petra; Yan, Jia; Schwandt, Melanie L; Stangl, Bethany L; Jerlhag, Elisabet; Engel, Jörgen A; Hodgkinson, Colin A; Ramchandani, Vijay A; Leggio, Lorenzo

2017-07-01

The orexigenic peptide ghrelin may enhance the incentive value of food-, drug- and alcohol-related rewards. Consistent with preclinical findings, human studies indicate a role of ghrelin in alcohol use disorders (AUD). In the present study an a priori hypothesis-driven analysis was conducted to investigate whether a Leu72Met missense polymorphism (rs696217) in the prepro-ghrelin gene (GHRL), is associated with AUD, alcohol consumption and subjective responses to alcohol. Association analysis was performed using the National Institute on Alcohol Abuse and Alcoholism (NIAAA) clinical sample, comprising AUD individuals and controls (N = 1127). Then, a post-hoc analysis using data from a human laboratory study of intravenous alcohol self-administration (IV-ASA, N = 144) was performed to investigate the association of this SNP with subjective responses following a fixed dose of alcohol (priming phase) and alcohol self-administration (ad libitum phase). The case-control study revealed a trend association (N = 1127, OR = 0.665, CI = 0.44-1.01, P = 0.056) between AUD diagnosis and Leu72Met. In AUD subjects, the SNP was associated with significantly lower average drinks per day (n = 567, β = -2.49, 95% CI = -4.34 to -0.64, P = 0.008) and significantly fewer heavy drinking days (n = 567, β = -12.00, 95% CI = -19.10 to -4.89, P < 0.001). The IV-ASA study further revealed that 72Met carriers had greater subjective responses to alcohol (P < 0.05) when compared to Leu72Leu both at priming and during ad lib self-administration. Although preliminary, these findings suggest that the Leu72Leu genotype may lead to increased risk of AUD possibly via mechanisms involving a lower response to alcohol resulting in excessive alcohol consumption. Further investigations are warranted. We investigated whether a Leu72Met missense polymorphism in the prepro-ghrelin gene, is associated with alcohol use disorder, alcohol consumption and subjective responses to alcohol. Although preliminary, results suggest that the Leu72Leu genotype may lead to increased risk of alcohol use disorder possibly via mechanisms involving a lower response to alcohol. Medical Council on Alcohol and Oxford University Press 2017. This work is written by (a) US Government employee(s) and is in the public domain in the US.

Detection of DNA from undeclared animal species in commercial elimination diets for dogs using PCR.

PubMed

Horvath-Ungerboeck, Christa; Widmann, Karoline; Handl, Stefanie

2017-08-01

Elimination diets are the gold standard for the diagnosis of adverse food reactions (AFR). A broad variety of commercial diets are available containing either hydrolysed protein or novel ingredients which claim to be suitable for elimination diets. Contamination may be one factor accounting for the failure of commercial elimination diet trials. To test commercial diets labelled as suitable for elimination diets for dogs, for DNA of animal origin other than that declared on the label. Twelve commercial dry and tinned dog food products were investigated for DNA of animal origin (chicken, turkey, beef, mutton and pork) using PCR testing. In nine of 10 over-the-counter diets, DNA of one or more animal species other than declared on the label was identified. The DNA most frequently detected was derived from beef (n = 8) and pork (n = 6). Two hydrolysed diets only contained DNA of the declared animal source. Over-the-counter "single protein diets" or canned meat products cannot be recommended for the diagnosis of dogs with AFR because contamination may cause the elimination diet to fail. © 2017 ESVD and ACVD.

RNA editing in the anticodon of tRNA Leu (CAA) occurs before group I intron splicing in plastids of a moss Takakia lepidozioides S. Hatt. & Inoue.

PubMed

Miyata, Y; Sugita, C; Maruyama, K; Sugita, M

2008-03-01

RNA editing of cytidine (C) to uridine (U) transitions occurs in plastids and mitochondria of most land plants. In this study, we amplified and sequenced the group I intron-containing tRNA Leu gene, trnL-CAA, from Takakia lepidozioides, a moss. DNA sequence analysis revealed that the T. lepidozioides tRNA Leu gene consisted of a 35-bp 5' exon, a 469-bp group I intron and a 50-bp 3' exon. The intron was inserted between the first and second position of the tRNA Leu anticodon. In general, plastid tRNA Leu genes with a group I intron code for a TAA anticodon in most land plants. This strongly suggests that the first nucleotide of the CAA anticodon could be edited in T. lepidozioides plastids. To investigate this possibility, we analysed cDNAs derived from the trnL-CAA transcripts. We demonstrated that the first nucleotide C of the anticodon was edited to create a canonical UAA anticodon in T. lepidozioides plastids. cDNA sequencing analyses of the spliced or unspliced tRNA Leu transcripts revealed that, while the spliced tRNA was completely edited, editing in the unspliced tRNAs were only partial. This is the first experimental evidence that the anticodon editing of tRNA occurs before RNA splicing in plastids. This suggests that this editing is a prerequisite to splicing of pre-tRNA Leu.

Preliminary Assessment of the Impact on Reactor Vessel dpa Rates Due to Installation of a Proposed Low Enriched Uranium (LEU) Core in the High Flux Isotope Reactor (HFIR)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Daily, Charles R.

2015-10-01

An assessment of the impact on the High Flux Isotope Reactor (HFIR) reactor vessel (RV) displacements-per-atom (dpa) rates due to operations with the proposed low enriched uranium (LEU) core described by Ilas and Primm has been performed and is presented herein. The analyses documented herein support the conclusion that conversion of HFIR to low-enriched uranium (LEU) core operations using the LEU core design of Ilas and Primm will have no negative impact on HFIR RV dpa rates. Since its inception, HFIR has been operated with highly enriched uranium (HEU) cores. As part of an effort sponsored by the National Nuclearmore » Security Administration (NNSA), conversion to LEU cores is being considered for future HFIR operations. The HFIR LEU configurations analyzed are consistent with the LEU core models used by Ilas and Primm and the HEU balance-of-plant models used by Risner and Blakeman in the latest analyses performed to support the HFIR materials surveillance program. The Risner and Blakeman analyses, as well as the studies documented herein, are the first to apply the hybrid transport methods available in the Automated Variance reduction Generator (ADVANTG) code to HFIR RV dpa rate calculations. These calculations have been performed on the Oak Ridge National Laboratory (ORNL) Institutional Cluster (OIC) with version 1.60 of the Monte Carlo N-Particle 5 (MCNP5) computer code.« less

Evaluation of neuropeptide loaded trimethyl chitosan nanoparticles for nose to brain delivery.

PubMed

Kumar, Manoj; Pandey, Ravi Shankar; Patra, Kartik Chandra; Jain, Sunil Kumar; Soni, Muarai Lal; Dangi, Jawahar Singh; Madan, Jitender

2013-10-01

Leucine-enkephalin (Leu-Enk) is a neurotransmitter or neuromodulator in pain transmission. Due to non-addictive opioid analgesic activity of this peptide, it might have great potential in pain management. Leu-Enk loaded N-trimethyl chitosan (TMC) nanoparticles were prepared and evaluated as a brain delivery vehicle via nasal route. TMC biopolymer was synthesized and analyzed by (1)H NMR spectroscopy. TMC nanoparticles were prepared by ionic gelation method. Mean peptide encapsulation efficiency and loading capacity were 78.28±3.8% and 14±1.3%, respectively. Mean particle size, polydispersity index and zeta potential were found to be 443±23 nm, 0.317±0.17 and +15±2 mV respectively for optimized formulations. Apparent permeability coefficient (Papp) of Leu-Enk released from nanoparticles across the porcine nasal mucosa was determined to be 7.45±0.30×10(-6) cm s(-1). Permeability of Leu-Enk released from nanoparticles was 35 fold improved from the nasal mucosa as compared to Leu-Enk solution. Fluorescent microscopy of brain sections of mice showed higher accumulation of fluorescent marker NBD-F labelled Leu-Enk, when administered nasally by TMC nanoparticles, while low brain uptake of marker solution was observed. Furthermore, enhancement in brain uptake resulted into significant improvement in the observed antinociceptive effect of Leu-Enk as evidenced by hot plate and acetic acid induced writhing assay. Copyright © 2013 Elsevier B.V. All rights reserved.

High plasma ghrelin protects from coronary heart disease and Leu72Leu polymorphism of ghrelin gene from cancer in healthy adults during the 19 years follow-up study.

PubMed

Laurila, M; Santaniemi, M; Kesäniemi, Y A; Ukkola, O

2014-11-01

The aim of our investigation was to find out if ghrelin concentrations or polymorphisms predict the future risk for cardiovascular diseases and cancer in a population-based cohort initiated in 1991 (491 hypertensive and 513 control subjects). Total mortality and hospital events were followed up for 19 years. Fasting total ghrelin concentrations were determined and Arg51Gln, Leu72Met and -501 A > C polymorphisms identified. Cox regression analysis was performed. The mean value in the control cohort was 674 pg/ml whereas in the hypertensive cohort it was 661 pg/ml. The associations found suggest that in the controls the highest ghrelin quartile protected from CHD (coronary heart disease). The results were significant without or with adjustments for age, sex, smoking, systolic blood pressure and LDL cholesterol, BMI, type 2 diabetes or QUICK index. C/C variant of the promoter associated with the prevention of IHD (ischemic heart disease) in the hypertensive group (p<0.05). The controls with the Leu72Leu genotype had less cancer (p<0.05). In conclusion, high plasma ghrelin concentration was related to protection from CHD and Leu72Leu genotype to prevention of cancer in healthy adults during the 19 years follow-up. C/C promoter protects from IHD in the hypertensive subjects. Copyright © 2014 Elsevier Inc. All rights reserved.

Naltrexone-loaded poly[La-(Glc-Leu)] polymeric microspheres for the treatment of alcohol dependence: in vitro characterization and in vivo biocompatibility assessment.

PubMed

Pagar, Kunal P; Vavia, Pradeep R

2014-06-01

The poly[La-(Glc-Leu)] copolymer was applied in the present investigation as polymeric carrier to fabricate naltrexone (NTX)-loaded poly[La-(Glc-Leu)] microspheres in the single emulsion solvent evaporation technique for the long-term treatment of alcohol dependence. Newly synthesized poly[La-(Glc-Leu)] copolymer exhibited diminished crystallanity, good biocompatibility and favorable biodegradability to be explored for drug delivery application. Scanning Electron Microscopy study revealed smooth and spherical-shaped NTX-loaded polymeric microspheres with a mean size of 10-90 µm. Influence of various decisive formulation variables such as amount of polymer, stabilizer concentration, homogenization speed, homogenization time, drug loading and organic-to-aqueous phase ratio on particle size, and entrapment efficiency was studied. Differential scanning calorimeter and X-ray diffractometry study confirmed the drug entrapment within polymer matrix into the microsphere environment. In vitro drug release showed the sustained drug release of formulation for the period of 28 d giving biphasic release pattern. Histological examination of NTX-loaded poly[La-(Glc-Leu)] microspheres injected intramuscularly into the thigh muscle of Wistar rats showed minimal inflammatory reaction, demonstrating that NTX-loaded microspheres were biocompatible. Insignificant increase in the serum creatine phosphokinase level (p < 0.05) as compared with the normal value revealed good muscle compatibility of the poly[La-(Glc-Leu)] microsphere system. Biocompatible nature and sustained drug-release action of poly[La-(Glc-Leu)] microspheres may have potential application in depot therapy.

Rapid detection of the addition of soybean proteins to cheese and other dairy products by reversed-phase perfusion chromatography.

PubMed

García, M C; Marina, M L

2006-04-01

The undeclared addition of soybean proteins to milk products is forbidden and a method is needed for food control and enforcement. This paper reports the development of a chromatographic method for routine analysis enabling the detection of the addition of soybean proteins to dairy products. A perfusion chromatography column and a linear binary gradient of acetonitrile-water-0.1% (v/v) trifluoroacetic acid at a temperature of 60 degrees C were used. A very simple sample treatment consisting of mixing the sample with a suitable solvent (Milli-Q water or bicarbonate buffer (pH=11)) and centrifuging was used. The method enabled the separation of soybean proteins from milk proteins in less than 4 min (at a flow-rate of 3 ml/min). The method has been successfully applied to the detection of soybean proteins in milk, cheese, yogurt, and enteral formula. The correct quantitation of these vegetable proteins has also been possible in milk adulterated at origin with known sources of soybean proteins. The application of the method to samples adulterated at origin also leads to interesting conclusions as to the effect of the processing conditions used for the preparation of each dairy product on the determination of soybean proteins.

Presence of undeclared peanut protein in chocolate bars imported from Europe.

PubMed

Vadas, Peter; Perelman, Boris

2003-10-01

Peanut allergens are both stable and potent and are capable of inducing anaphylactic reactions at low concentrations. Consequently, the consumption of peanuts remains the most common cause of food-induced anaphylactic death. Since accidental exposure to peanuts is a common cause of potentially fatal anaphylaxis in peanut-allergic individuals, we tested for the presence of peanut protein in chocolate bars produced in Europe and North America that did not list peanuts as an ingredient. Ninety-two chocolate bars, of which 32 were manufactured in North America and 60 were imported from Europe, were tested by the Veratox assay. None of the 32 North American chocolate products, including 19 with precautionary labeling, contained detectable peanut protein. In contrast, 30.8% of products from western Europe without precautionary labeling contained detectable levels of peanut protein. Sixty-two percent of products from eastern Europe without precautionary labeling contained detectable peanut protein at levels of up to 245 ppm. The absence of precautionary labeling and the absence of the declaration of "peanut" as an ingredient in chocolate bars made in eastern and central Europe were not found to guarantee that these products were actually free of contaminating peanut protein. In contrast, North American manufacturers have attained a consistent level of safety and reliability for peanut-allergic consumers.

The response of weaned piglets to dietary valine and leucine.

PubMed

Meyer, F; Jansen van Rensburg, C; Gous, R M

2017-08-01

Valine (Val) is considered to be the fifth-limiting amino acid in a maize-soyabean meal diet for pigs. Excess leucine (Leu) levels often occur in commercial diets, which may attenuate the effect of Val deficiency because of an increased oxidation of Val. The objective of the present experiment was to determine the effect of increasing concentrations of Leu on the response of young piglets to dietary Val. In all, 75 Large White×Landrace entire male pigs, 44 days of age and with a mean starting weight of 13.5 kg, were used. Three of these were sacrificed at the start to determine their mean initial chemical composition. A summit feed first limiting in Val was serially diluted with a non-protein diluent to produce a series of five digestible Val concentrations of 11.9, 10.1, 8.3, 6.6 and 4.8 g/kg, with a sixth treatment being added to test that the feeds were limiting in Val. Three identical Val series, each with six levels of Val, were supplemented with increasing amounts of Leu (23, 45 and 67 g/kg), thus 18 treatments in total. All pigs were killed at the end of the trial after 18 days for analysis of water, protein, lipid and ash in the carcass. The levels of Val and Leu and their interaction significantly influenced all the measurements taken in the trial. Daily gain in liveweight, water and protein, and feed conversion efficiency all increased with dietary Val content, whereas feed intake decreased as both Val and Leu contents increased. The deleterious effect of increased Leu on feed intake and growth was more marked at lower levels of Val. Supplementing the feed with the lowest Val content with additional Val largely overcame the effect of excess Leu. The efficiency of utilisation of Val for protein growth was unaffected by the level of Leu in the feed, the primary response to excess Leu being a reduction in feed intake. An intake of around 9 g Val/day yielded maximal protein growth during the period from 44 to 62 days of age in pigs of the genotype used in this trial.

Purification and structural determination of an inhibitor of starfish oocyte maturation from a Bacillus species.

PubMed Central

Toraya, T; Maoka, T; Tsuji, H; Kobayashi, M

1995-01-01

Inhibitors of bacterial origins of starfish oocyte maturation were sought to obtain biologically active substances which act on either hormonal signal transduction or cell cycle regulation. An oocyte maturation-inhibiting substance found in culture fluid of a Bacillus species was purified to homogeneity. This substance possessed the nature of a detergent and specifically inhibited 1-methyladenine-induced oocyte maturation (50% inhibitory concentration, 3.3 microM) but not dithiothreitol-induced maturation. Its total structure was established to be the lactone of 3-hydroxy-13-methyltetradecanoyl-Glu-Leu-Leu-Val-Asp-Leu -Leu through COOH of the carboxy-terminal Leu. This structure is identical to surfactin, although although the configuration of the substance's amino acid residues has not yet been determined. Surfactin was shown to be identical with this substance in its inhibitory effect on starfish oocyte maturation as well as its chromatographic and electrophoretic properties. Therefore, it was concluded that the oocyte maturation-inhibiting substance produced by a Bacillus species is surfactin. PMID:7646018

The manufacture of LEU fuel elements at Dounreay

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gibson, J.

1997-08-01

Two LEU test elements are being manufactured at Dounreay for test irradiation in the HFR at Petten, The Netherlands. This paper describes the installation of equipment and the development of the fabrication and inspection techniques necessary for the manufacture of LEU fuel plates. The author`s experience in overcoming the technical problems of stray fuel particles, dog-boning, uranium homogeneity and the measurement of uranium distribution is also described.

Purification and characterization of galanin and scyliorhinin I from the hybrid sturgeon, Scaphirhynchus platorynchus x Scaphirhynchus albus (Acipenseriformes).

PubMed

Wang, Y; Barton, B A; Thim, L; Nielsen, P F; Conlon, J M

1999-01-01

The sturgeons (order Acipenseriformes) are extant representatives of a group of ancient Actinopterygian (ray-finned) fish. Galanin and scyliorhinin I (a tachykinin with limited structural similarity to mammalian substance P) have been isolated from an extract of the gastrointestinal tract of a sturgeon (an F1 hybrid between the shovelnose sturgeon, Scaphirhynchus platorynchus, and the pallid sturgeon, Scaphirhynchus albus). The primary structure of sturgeon galanin (Gly-Trp-Thr-Leu-Asn-Ser-Ala-Gly-Tyr-Leu10-Leu-Gly-Pro-His-Ala-Val -As p-Gly-His-Arg20-Ser-Leu-Ser-Asp-Lys-His-Gly-Leu-Pro.NH2) contains only two amino acid substitutions (Ser23 --> Asn and Pro29 --> Ala) compared with galanin from the bowfin, Amia calva (Amiiformes), but five amino acid substitutions compared with galanin from the trout (Teleostei). Similarly, the sturgeon tachykinin (Ser-Lys-Tyr-His-Gln-Phe-Tyr-Gly-Leu-Met.NH2) contains only one amino acid substitution (Tyr3 --> Ser) compared with scyliorhinin I previously isolated from bowfin stomach but five amino acid substitutions compared with trout substance P. The data support the hypothesis that the Acipenseriformes and the basal Neopterygians (gars and bowfin) share a close phylogenetic relationship. Copyright 1999 Academic Press.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bunnett, N.W.; Walsh, J.H.; Debas, H.T.

Peptidases degrade neuropeptides and thereby limit the duration and extent of their influence. This investigation examined the importance of peptidases in the degradation of the neuropeptide enkephalin in the stomach wall of the rat. Metabolism of (Leu5)- and (D-Ala2)(Leu5)enkephalin by gastric membranes was examined in vitro. Degradation of (Tyr1-3H)(Leu5)enkephalin was studied in the gastric submucosa of anesthetized and conscious rats in vivo by using a catheter to deliver peptide to tissues and implanted dialysis fibers to collect the metabolites. Specific inhibitors were used to assess the contribution of particular enzymes. (Leu5)- and (Tyr1-3H)(Leu5)enkephalin were metabolized by membranes and in themore » stomach wall by hydrolysis of the Tyr1-Gly2 bond. Degradation was inhibited by the aminopeptidase inhibitor amastatin (10(-5) M in vitro, 10 nmol in vivo). Inhibitors of endopeptidase-24.11 (phosphoramidon) and angiotensin-converting enzyme (captopril) did not inhibit degradation. Metabolism of the aminopeptidase-resistant analogue (D-Ala2)(Leu5)enkephalin by membranes was unaffected by amastatin and weakly inhibited by phosphoramidon affected by amastatin and weakly inhibited by phosphoramidon and captopril. A carboxypeptidase removed the COOH-terminal leucine residue and made a substantial contribution to degradation of both peptides by gastric membranes.« less

Purification and identification of corn peptides that facilitate alcohol metabolism by semi-preparative high-performance liquid chromatography and nano liquid chromatography with electrospray ionization tandem mass spectrometry.

PubMed

Ma, Zhi-Li; Hou, Tao; Shi, Wen; Liu, Wei-Wei; Ibrahim, Salam A; He, Hui

2016-11-01

In this study, peptides that facilitate alcohol metabolism were purified and identified from corn protein hydrolysates. The ultra-filtered fraction with a molecular weight < 3 kDa (F3) potential activity was separated into six fractions (F3-H1-F3-H6) by semi-preparative high-performance liquid chromatography. Among the resultant six fractions, F3-H4 and F3-H5 exhibited the highest ability to eliminate alcohol in vivo. A total of 16 peptides with strong signal values were identified from F3-H4 and F3-H5 fractions by nano liquid chromatography coupled with electrospray ionization tandem mass spectrometry. Several identified peptides were then selected and synthesized to determine their potential to facilitate alcohol metabolism. We found that Leu-Leu and Pro-Phe were the key structure units in Gln-Leu-Leu-Pro-Phe responsible for this peptide's ability to facilitate alcohol metabolism. However, the role of Leu-Leu and Pro-Phe may be affected by peptide chain length and hydrophobic properties. Our results have thus provided some insight into the study of the structure-activity relationships of corn peptides. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Cholecystokinin octa- and tetrapeptide degradation by synaptic membranes. I. Evidence for competition with enkephalins for in vitro common degradation pathways.

PubMed

Deschodt-Lanckman, M; Bui, N D

1981-01-01

Degradation of CCK-4 and -8 by purified synaptic membranes was followed by measuring the fluorescence of tryptophan released from the peptides after separation of degradation products by HPLC. For enkephalins and related fragments, the release of tyrosine was monitored using the same method. Kinetics of hydrolysis of CCK-like peptides indicated a rapid processing of CCK-4 and a slower breakdown of CCK-8 (with a greater resistance of the sulfated form of CCK-8 as compared to the unsulfated peptide). Leu- and met-enkephalins were degraded at the same rate while their N-terminal tri- and dipeptides were hydrolysed more slowly. When CCK-4 or CCK-8 were incubated in the presence of leu-enkephalin, a dose-dependent inhibition of the release of tryptophan was observed. Enkaphalin fragments do not modify the kinetics of degradation of CCK-4. The degradation of leu-enkephalin was inhibited in a dose-dependent manner by the presence of CCK-related peptides in the medium. After solubilization of membrane-bound enzymes by Triton X-100 followed by chromatography on DEAE cellulose, five peaks of CCK-4 degrading activity were detected (two minor and three major peaks). With enkephalin as substrate, five peaks were also observed; the three major activities were the same as those detected for CCK-4.

A Quantitative Tool to Distinguish Isobaric Leucine and Isoleucine Residues for Mass Spectrometry-Based De Novo Monoclonal Antibody Sequencing

NASA Astrophysics Data System (ADS)

Poston, Chloe N.; Higgs, Richard E.; You, Jinsam; Gelfanova, Valentina; Hale, John E.; Knierman, Michael D.; Siegel, Robert; Gutierrez, Jesus A.

2014-07-01

De novo sequencing by mass spectrometry (MS) allows for the determination of the complete amino acid (AA) sequence of a given protein based on the mass difference of detected ions from MS/MS fragmentation spectra. The technique relies on obtaining specific masses that can be attributed to characteristic theoretical masses of AAs. A major limitation of de novo sequencing by MS is the inability to distinguish between the isobaric residues leucine (Leu) and isoleucine (Ile). Incorrect identification of Ile as Leu or vice versa often results in loss of activity in recombinant antibodies. This functional ambiguity is commonly resolved with costly and time-consuming AA mutation and peptide sequencing experiments. Here, we describe a set of orthogonal biochemical protocols, which experimentally determine the identity of Ile or Leu residues in monoclonal antibodies (mAb) based on the selectivity that leucine aminopeptidase shows for n-terminal Leu residues and the cleavage preference for Leu by chymotrypsin. The resulting observations are combined with germline frequencies and incorporated into a logistic regression model, called Predictor for Xle Sites (PXleS) to provide a statistical likelihood for the identity of Leu at an ambiguous site. We demonstrate that PXleS can generate a probability for an Xle site in mAbs with 96% accuracy. The implementation of PXleS precludes the expression of several possible sequences and, therefore, reduces the overall time and resources required to go from spectra generation to a biologically active sequence for a mAb when an Ile or Leu residue is in question.

A glycine-leucine-rich peptide structurally related to the plasticins from skin secretions of the frog Leptodactylus laticeps (Leptodactylidae).

PubMed

Conlon, J Michael; Abdel-Wahab, Yasser H A; Flatt, Peter R; Leprince, Jérôme; Vaudry, Hubert; Jouenne, Thierry; Condamine, Eric

2009-05-01

A glycine-leucine-rich peptide was isolated from norepinephrine-stimulated skin secretions of the Sante Fe frog Leptodactylus laticeps (Leptodactylidae) whose primary structure (Gly-Leu-Val-Asn-Gly-Leu-Leu-Ser-Ser-Val-Leu-Gly-Gly-Gly-Gln-Gly-Gly-Gly-Gly-Leu-Leu-Gly-Gly-Ile-Leu) contains the (GXXXG)(3) motif found in the plasticins, previously identified only in phyllomedusid frogs (Hylidae). Circular dichroism studies showed that the secondary structure of the peptide, termed plasticin-L1, was markedly solvent-dependent displaying a random coil conformation in water, a beta-sheet structure in methanol, and an alpha-helical conformation in 50% trifluoroethanol-water. A synthetic replicate of the peptide did not inhibit the growth of Escherichia coli or Staphylococcus aureus or lyse human erythrocytes at concentrations up to 500 microM. At relatively high concentrations (>or=1 microM), the peptide produced a significant (P<0.05), although modest (139% of basal rate at 3 microM), increase in the rate of glucose-induced release of insulin from rat clonal BRIN-BD11 beta cells without increasing the rate of release of lactate dehydrogenase. A peptide, termed ocellatin-L2 was also identified in the skin secretion that was identical to the previously described ocellatin-L1 except for the substitution Asn(23)-->Asp. Ocellatin-L2 was devoid of antimicrobial and hemolytic activity but also showed significant activity in stimulating insulin release from BRIN-BD11 cells (181% of basal rate at 3 microM).

Hypoglycemic and Hypolipidemic Effects of Leucine, Zinc, and Chromium, Alone and in Combination, in Rats with Type 2 Diabetes.

PubMed

Sadri, Hassan; Larki, Negar Nowroozi; Kolahian, Saeed

2017-12-01

For the increasing development of diabetes, dietary habits and using appropriate supplements can play important roles in the treatment or reduction of risk for this disease. The objective of this study was to investigate the effects of leucine (Leu), zinc (Zn), and chromium (Cr) supplementation, alone or in combination, in rats with type 2 diabetes (T2D). Seventy-seven adult male Wistar rats were randomly assigned in 11 groups, using nutritional supplements and insulin (INS) or glibenclamide (GLC). Supplementing Leu significantly reduced blood glucose, triglycerides (TG), nonesterified fatty acids (NEFA), low-density lipoprotein (LDL), and increased high-density lipoprotein (HDL) concentrations compared to vehicle-treated T2D animals, and those improvements were associated with reduced area under the 2-h blood glucose response curve (AUC). Supplementation of T2D animals with Zn improved serum lipid profile as well as blood glucose concentrations but was not comparable with the INS, GLC, and Leu groups. Supplementary Cr did not improve blood glucose and AUC in T2D rats, whereas it reduced serum TG and LDL and increased HDL concentrations. In conclusion, supplementation of diabetic rats with Leu was more effective in improving blood glucose and consequently decreasing glucose AUC than other nutritional supplements. Supplementary Zn and Cr only improved serum lipid profile. The combination of the nutritional supplements did not improve blood glucose level. Nevertheless, supplementation with Leu-Zn, Leu-Cr, Zn-Cr, and Leu-Zn-Cr led to an improved response in serum lipid profile over each supplement given alone.

A quantitative tool to distinguish isobaric leucine and isoleucine residues for mass spectrometry-based de novo monoclonal antibody sequencing.

PubMed

Poston, Chloe N; Higgs, Richard E; You, Jinsam; Gelfanova, Valentina; Hale, John E; Knierman, Michael D; Siegel, Robert; Gutierrez, Jesus A

2014-07-01

De novo sequencing by mass spectrometry (MS) allows for the determination of the complete amino acid (AA) sequence of a given protein based on the mass difference of detected ions from MS/MS fragmentation spectra. The technique relies on obtaining specific masses that can be attributed to characteristic theoretical masses of AAs. A major limitation of de novo sequencing by MS is the inability to distinguish between the isobaric residues leucine (Leu) and isoleucine (Ile). Incorrect identification of Ile as Leu or vice versa often results in loss of activity in recombinant antibodies. This functional ambiguity is commonly resolved with costly and time-consuming AA mutation and peptide sequencing experiments. Here, we describe a set of orthogonal biochemical protocols, which experimentally determine the identity of Ile or Leu residues in monoclonal antibodies (mAb) based on the selectivity that leucine aminopeptidase shows for n-terminal Leu residues and the cleavage preference for Leu by chymotrypsin. The resulting observations are combined with germline frequencies and incorporated into a logistic regression model, called Predictor for Xle Sites (PXleS) to provide a statistical likelihood for the identity of Leu at an ambiguous site. We demonstrate that PXleS can generate a probability for an Xle site in mAbs with 96% accuracy. The implementation of PXleS precludes the expression of several possible sequences and, therefore, reduces the overall time and resources required to go from spectra generation to a biologically active sequence for a mAb when an Ile or Leu residue is in question.

Relationships between coastal bacterioplankton growth rates and biomass production: comparison of leucine and thymidine uptake with single-cell physiological characteristics.

PubMed

Franco-Vidal, Leticia; Morán, Xosé Anxelu G

2011-02-01

Specific growth rates of heterotrophic bacterioplankton have been frequently estimated from in situ bacterial production (BP) to biomass (BB) ratios, using a series of assumptions that may result in serious discrepancies with values obtained from predator-free cultures. Here, we used both types of approaches together with a comprehensive assessment of single-cell physiological characteristics (membrane integrity, nucleic acid content, and active respiration) of coastal bacterioplankton during a complete annual cycle (February 2007-January 2008) in the southern Bay of Biscay off Xixón, Spain. Both leucine and thymidine incorporation rates were used in conjunction with empirical tracer to carbon or cells conversion factors (eCFs) to accurately derive BP. Leu and TdR incorporation rates covaried year-round, as did the corresponding eCFs at 0 and 50 m depth. eCFs peaked in autumn, with mean annual values close to the theoretical ones (3.4 kg C mol Leu(-1) and 2.0 × 10(18) cells mol TdR(-1)). Bacterial abundance (0.2-1.5 × 10(6) cells L(-1)) showed a bimodal distribution with maxima in May and October and minima in March. Live (membrane-intact) cells dominated year-round (79-97%), with high nucleic acid cells (42-88%) and actively respiring bacteria (CTC+, 1-16%) showing distinct surface maxima in April and July, respectively. BB (557-1,558 mg C m(-2)) and BP (7-139 mg C m(-2) day(-1)) presented two distinct peaks in spring and autumn, both of similar size due to a strong upwelling event observed in September. Specific growth rates (0.35-3.8 day(-1)) were one order of magnitude higher in predator-free incubations than bacterial turnover rates derived from integrated BP:BB ratios (0.01-0.16 and 0.01-0.09 day(-1), for Leu and TdR, respectively) and were not correlated, probably due to a significant contribution of low activity cells to total standing stocks. The Leu:TdR molar ratio averaged for the water column (6.6-25.5) decreased significantly with higher integrated BB, indicating that low standing stocks tend to present unbalanced growth. Discrepancies about the true magnitude of specific growth rates must be solved before fully appreciating the role of bacteria in the ocean carbon cycle.

Acute gonadotropin-releasing hormone agonist treatment enhances extinction memory in male rats.

PubMed

Maeng, L Y; Taha, M B; Cover, K K; Glynn, S S; Murillo, M; Lebron-Milad, K; Milad, M R

2017-08-01

Leuprolide acetate (LEU), also known as Lupron, is commonly used to treat prostate cancer in men. As a gonadotropin-releasing hormone (GnRH) receptor agonist, it initially stimulates the release of gonadal hormones, testosterone (T) and estradiol. This surge eventually suppresses these hormones, preventing the further growth and spread of cancer cells. Individuals receiving this treatment often report anxiety and cognitive changes, but LEU's effects on the neural mechanisms that are involved in anxiety during the trajectory of treatment are not well known. In this study, we examined the acute effects of LEU on fear extinction, hypothesizing that increased T levels following a single administration of LEU will facilitate extinction recall by altering neuronal activity within the fear extinction circuitry. Two groups of naïve adult male rats underwent a 3-day fear conditioning, extinction, and recall experiment. The delayed group (n=15) received a single injection of vehicle or LEU (1.2mg/kg) 3weeks before behavioral testing. The acute group (n=25) received an injection one day after fear conditioning, 30min prior to extinction training. Following recall, the brains for all animals were collected for c-fos immunohistochemistry. Blood samples were also collected and assayed for T levels. Acute administration of LEU increased serum T levels during extinction training and enhanced extinction recall 24h later. This enhanced extinction memory was correlated with increased c-fos activity within the infralimbic cortex and amygdala, which was not observed in the delayed group. These results suggest that the elevation in T induced by acute administration of LEU can influence extinction memory consolidation, perhaps through modification of neuronal activity within the infralimbic cortex and amygdala. This may be an important consideration in clinical applications of LEU and its effects on anxiety and cognition. Copyright © 2017 Elsevier Ltd. All rights reserved.

A new variation in the promoter region, the -604 C>T, and the Leu72Met polymorphism of the ghrelin gene are associated with protection to insulin resistance.

PubMed

Zavarella, S; Petrone, A; Zampetti, S; Gueorguiev, M; Spoletini, M; Mein, C A; Leto, G; Korbonits, M; Buzzetti, R

2008-04-01

Previous studies suggested that polymorphisms in the coding region of the preproghrelin were involved in the etiology of obesity and might modulate glucose-induced insulin secretion. We evaluated the association of a new variation, -604C>T, in the promoter region of the ghrelin gene, of Leu72Met (247C>A) and of Gln90Leu (265A>T), all haplotype-tagging single nucleotide polymorphisms (SNPs), with measures of insulin sensitivity in 1420 adult individuals. The three SNPs were genotyped using ABI PRISM 7900 HT Sequence Detection System. We used multiple linear regression analysis for quantitative traits and THESIAS software for haplotype analysis. We observed a protective effect exerted by Met72 variant of Leu72Met SNP on insulin resistance parameters; a significant decreasing trend from Leu/Leu to Leu/Met and to Met/Met homozygous subjects in triglycerides, fasting insulin levels and HOMA-IR index (P=0.02, 0.01 and 0.003, respectively), and, consistently, an increase in ghrelin levels (P=0.003) was found. A significant decrease from CC to TC and to TT genotypes in insulin levels and HOMA-IR index was also detected (P=0.00l for both), but only in subjects homozygous for Leu72, where the protective effect of Met72 was not present. The haplotype analysis results supported the data obtained by the evaluation of each single SNP, showing the highest value of insulin levels and HOMA-IR index in the -604(c)247(c) haplotype intermediate value in -604(T)247(C) and lowest value in -604(C)247(A). Our observations suggest a protective role of the Met72 variant and of -604 T allele in modulating insulin resistance. These SNPs or an unknown functional variant in linkage disequilibrium could increase ghrelin levels and probably insulin sensitivity.

Maternal insulin-like growth factor-II promotes placental functional development via the type 2 IGF receptor in the guinea pig.

PubMed

Sferruzzi-Perri, A N; Owens, J A; Standen, P; Roberts, C T

2008-04-01

In guinea pigs, maternal insulin-like growth factor (IGF) infusion in early-pregnancy enhances placental transport near-term, increasing fetal growth and survival. The effects of IGF-II, but not IGF-I, appear due to enhanced placental labyrinthine (exchange) development. To determine if the type-2 IGF receptor (IGF2R) mediates these distinct actions of exogenous IGF-II in the mother, we compared the impact of IGF-II with an IGF-II analogue, Leu(27)-IGF-II, which only binds the IGF2R. IGF-II, Leu(27)-IGF-II (1mg/kg per day.sc) or vehicle were infused from days 20-38 of pregnancy (term = 67 days) and placental structure and uptake and transfer of [(3)H]-methyl-D-glucose (MG) and [(14)C]-amino-isobutyric acid (AIB) and fetal growth and plasma metabolites, were measured on day 62. Both IGF-II and Leu(27)-IGF-II increased the volume of placental labyrinth, trophoblast and maternal blood space within the labyrinth and total surface area of trophoblast for exchange, compared to vehicle. Leu(27)-IGF-II also reduced the barrier to diffusion (trophoblast thickness) compared to vehicle and IGF-II. Both IGF-II and Leu(27)-IGF-II increased fetal plasma amino acid concentrations and placental transfer of MG to the fetus compared to vehicle, with Leu(27)-IGF-II also increasing AIB transport compared with vehicle and IGF-II. In addition, Leu(27)-IGF-II increased fetal weight compared to vehicle. In conclusion, maternal treatment with IGF-II or Leu(27)-IGF-II in early gestation, induce similar placental and fetal outcomes near term. This suggests that maternal IGF-II in early gestation acts in part via the IGF2R to persistently enhance placental functional development and nutrient delivery and promote fetal growth.

Rapid LC-MS method for the detection of common fragrances in personal care products without sample preparation.

PubMed

Famiglini, Giorgio; Termopoli, Veronica; Palma, Pierangela; Capriotti, Fabiana; Cappiello, Achille

2014-05-01

An LC-MS method for the analysis of personal care and household products without sample preparation is presented. The method takes advantage of the Direct-electron ionization (EI) LC-MS interface for the quantitation of principal components, as well as for the identification of unknown or undeclared ingredients. The technique has proven its inertness toward matrix effects and the electron ionization allows quantitation and library identification. Commercially available products (shower gel, perfume, and hand cream) were diluted with methanol and injected directly into a nano-LC column. Limonene, linalool, and citral were selected as target compounds because of their use as fragrances in toiletry and detergent products. These and all other fragrances are commonly determined with GC-MS analysis, prior to sample cleanup, a procedure that can lead to analytes loss. The selected compounds are not detected with ESI because of their poor or very low response. Figures of merit and validation studies were executed and special attention was devoted to matrix-effects evaluation, because a sample preparation procedure is not involved. No matrix effects were observed, and the repeatability was excellent even after several weeks of operation. Products composition was investigated in full scan mode to determine the presence of unknown or not listed ingredients. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Progress of the RERTR program in 2001.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Travelli, A.

2002-03-07

This paper describes the 2001 progress achieved by the Reduced Enrichment for Research and Test Reactors (RERTR) Program in collaboration with its many international partners. Postirradiation examinations of microplates have continued to reveal excellent irradiation behavior of U-Mo dispersion fuels in a variety of compositions and irradiating conditions. Irradiation of two new batches of miniplates of greater sizes was completed in the ATR to investigate the swelling behavior of these fuels under prototypic conditions. These materials hold the promise of achieving the program goal of developing LEU research reactor fuels with uranium densities in the 8-9 g/cm{sup 3} range. Qualificationmore » of the U-Mo dispersion fuels has been delayed by a patent issue involving KAERI. Test fuel elements with uranium density of 6 g/cm{sup 3} are being fabricated by BWXT and are expected to begin undergoing irradiation in the HFR-Petten reactor around March 2003, with a goal of qualifying this fuel by mid-2005. U-Mo fuel with uranium density of 8-9 g/cm{sup 3} is expected to be qualified by mid-2007. Final irradiation tests of LEU {sup 99}Mo targets in the RAS-GAS reactor at BATAN, in Indonesia, had to be postponed because of the 9/11 attacks, but the results collected to date indicate that these targets will soon be ready for commercial production. Excellent cooperation is also in progress with the CNEA in Argentina, MDSN/AECL in Canada, and ANSTO in Australia. Irradiation testing of five WWR-M2 tube-type fuel assemblies fabricated by the NZChK and containing LEU UO{sub 2} dispersion fuel was successfully completed within the Russian RERTR program. A new LEU U-Mo pin-type fuel that could be used to convert most Russian-designed research reactors has been developed by VNIINM and is ready for testing. Four additional shipments containing 822 spent fuel assemblies from foreign research reactors were accepted by the U.S. by September 30, 2001. Altogether, 4,562 spent fuel assemblies from foreign research reactors had been received by that date by the U.S. under the FRR SNF acceptance policy. The RERTR program is aggressively pursuing qualification of high-density LEU U-Mo dispersion fuels, with the dual goal of enabling further conversions and of developing a substitute for LEU silicide fuels that can be more easily disposed of after expiration of the U.S. FRR SNF Acceptance Program. As in the past, the success of the RERTR program will depend on the international friendship and cooperation that has always been its trademark.« less

Increasing the availability of threonine, isoleucine, valine, and leucine relative to lysine while maintaining an ideal ratio of lysine:methionine alters mammary cellular metabolites, mammalian target of rapamycin signaling, and gene transcription.

PubMed

Dong, X; Zhou, Z; Wang, L; Saremi, B; Helmbrecht, A; Wang, Z; Loor, J J

2018-06-01

Amino acids not only serve as precursors for protein synthesis but also function as signaling molecules that can regulate the mammalian target of rapamycin (mTOR) pathway. Methionine and Lys are the most-limiting AA for milk production and a ratio of ∼3:1 Lys:Met in the metabolizable protein has been determined to be ideal. Besides Met and Lys, recent studies have evaluated Ile, Leu, Val, and Thr as potentially limiting for milk protein synthesis. The objective of this experiment was to determine if varying the ratio of Lys:Thr, Lys:Ile, Lys:Val, and Lys:Leu while maintaining an ideal ratio of Lys:Met and fixed ratio of other essential AA (IPAA) elicits changes in intracellular metabolites, gene transcription related to protein synthesis, and phosphorylation status of mTOR pathway proteins. Immortalized bovine mammary epithelial cell line (MAC-T) cells were incubated for 12 h (n = 5 replicates/treatment) with IPAA (2.9:1 Lys:Met; 1.8:1 Lys:Thr; 2.38:1 Lys:His; 1.23:1 Lys:Val; 1.45:1 Lys:Ile; 0.85:1 Lys:Leu; 2.08:1 Lys:Arg) or IPAA supplemented with Thr, Ile, Val, and Leu to achieve a Lys:Thr 1.3:1 (LT1.3), Lys:Ile 1.29:1 (LI1.29), Lys:Val 1.12:1 (LV1.12), or Lys:Leu 0.78:1 (LL0.78). Compared with IPAA, metabolomics via gas chromatography-mass spectrometry revealed that increases in availability of Thr, Ile, Val, and Leu led to greater concentrations of essential AA (Leu, Ile, Thr), nonessential AA (Gly, Glu, Gln, Ser, Pro, Asp), and various metabolites including uric acid, phosphoric acid, N-acetylglutamic acid, and intermediates of glycolysis and the tricarboxylic acid cycle. Compared with other treatments, LV1.12 led to greater phosphorylation status of serine/threonine kinase B (Akt), mTORC1, and ribosomal protein S6 and lower phosphorylation of α subunit of eukaryotic translation initiation factor 2. In addition, LV1.12 upregulated abundance of CSN2 and both the abundance and promoter methylation of CSN1S1. Although LI1.29 led to the second highest response in mTORC1 phosphorylation status, it resulted in the lowest phosphorylation of Akt and eEF2 and mRNA abundance of CSN2 and various AA transporters (SLC7A5, SLC36A1, SLC38A2, SLC38A9, SLC43A1). Overall, data indicate that an increase in Val at an ideal ratio of Lys:Met could further enhance milk protein synthesis by altering intracellular concentrations of essential AA and metabolites that could play a regulatory role, increasing phosphorylation status of mTORC1 and key signaling proteins, and upregulation of AA transporters. The Authors. Published by FASS Inc. and Elsevier Inc. on behalf of the American Dairy Science Association®. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/3.0/).

Purification and structural characterization of insulin and glucagon from the bichir Polypterus senegalis (Actinopterygii: Polypteriformes).

PubMed

Conlon, J M; Fan, H; Fritzsch, B

1998-01-01

The Polypteriformes (bichirs and reedfish) are a family of ray-finned fishes of ancient lineage. Insulin has been isolated from an extract of the pancreas and upper gastrointestinal tract of the bichir Polypterus senegalis and its primary structure established as A-chain: Gly-Ile-Val-Glu-Gln-Cys-Cys-Asp-Thr-Pro10-Cys-Ser- Leu-Tyr-Asp-Leu-Glu-Asn-Tyr-Cys20-Asn: B-chain: Ala-Ala-Asn-Arg-His-Leu-Cys-Gly-Ser-His10-Leu-Val- Glu-Ala-Leu-Tyr-Leu-Val-Cys-Gly20-Asn-Arg-Gly-Phe- Phe-Tyr-Ile-Pro-Ser-Lys30-Met. Despite the fact that Polypterus insulin contains several unusual structural features that are not found in insulins from other jawed fish (Asp at A-8, Thr at A-9, Arg at B-4, Asn at B-21, Ile at B-27, Met at B-31), all the residues in human insulin that are involved in receptor binding, dimerization, and hexamerization have been conserved. A comparison of the structures of insulins from a range of species indicates that Polypterus insulin most closely resembles paddlefish insulin II (seven amino acid substitutions). In contrast, Polypterus glucagon (His-Ser- Gln-Gly-Thr-Phe-Thr-Asn-Asp-Tyr10-Thr-Lys-Tyr- Gln-Asp-Ser-Arg-Arg-Ala-Gln20-Asp-Phe-Val-Gln- Trp-Leu-Met-Ser-Asn) most closely resembles the glucagons from the gar Lepisosteus spatula and the bowfin Amia calva (four amino acid substitutions). The data are consistent with the conclusion based on comparison of morphological characteristics that the Polypterids are the most basal living group of the Actinopterygians with evolutionary connections to both the Acipenserids and the Neopterygians.

Mapping of enkephalins and adrenocorticotropic hormone in the squirrel monkey brainstem.

PubMed

Duque-Díaz, Ewing; Díaz-Cabiale, Zaida; Narváez, José Angel; Coveñas, Rafael

2017-03-01

An immunocytochemical technique has been used to study for the first time the distribution of fibers and cell bodies containing leucine-enkephalin (leu-enk), methionine-enkephalin (met-enk) or adrenocorticotropic hormone (ACTH) in the whole brainstem of the squirrel monkey Saimiri sciureus. Cell bodies containing leu-enk or met-enk were found in the superior colliculus and the formatio reticularis tegmenti mesencephali, respectively. No immunoreactive cell bodies containing ACTH were observed. Leu-enk-immunoreactive fibers were observed in 40 brainstem nuclei/tracts/regions, fibers containing met-enk were found in 38 brainstem nuclei/tracts/regions and fibers containing ACTH were found in 26 nuclei/tracts/regions. In the latter case, the density of immunoreactive fibers was always low. A high/moderate density of leu-enk- or met-enk-immunoreactive fibers were found in 18 and 16 brainstem nuclei/tracts/regions, respectively. The distribution of immunoreactive fibers containing leu-enk or met-enk was quite similar, with both leu-enk and met-enk observed in 82.5 % of the squirrel monkey brainstem nuclei/tracts/regions. This relationship is less marked for met-enk and ACTH (60.5 %) and even lower for leu-enk and ACTH (52.5 %). In 42.5 % of the nuclei/tracts/regions of the squirrel monkey brainstem (colliculus superior, substantia grisea centralis, nucleus interpeduncularis, nucleus tractus spinalis nervi trigemini, nucleus tractus solitarii, nucleus parabrachialis, formatio reticularis, substantia nigra), we observed fibers containing all three neuropeptides. The widespread distribution reported here suggests that enkephalins and ACTH can be involved in several physiological functions. The distribution of the immunoreactive fibers reported here is quite similar to that previously reported for enkephalins and ACTH in Macaca species and humans.

2'-O-methyl-5-formylcytidine (f5Cm), a new modified nucleotide at the 'wobble' of two cytoplasmic tRNAs Leu (NAA) from bovine liver.

PubMed Central

Païs de Barros, J P; Keith, G; El Adlouni, C; Glasser, A L; Mack, G; Dirheimer, G; Desgrès, J

1996-01-01

The nucleotide analysis of a cytoplasmic tRNA(Leu) isolated from bovine liver revealed the presence of an unknown modified nucleotide N. The corresponding N nucleoside was isolated by different enzymatic and chromatographic protocols from a partially purified preparation of this tRNA(Leu). Its chemical characterization was determined from its chromatographic properties, UV-absorption spectroscopy and mass spectrometric measurements, as well as from those of the borohydride reduced N nucleoside and its etheno-trimethylsilyl derivative. The structure of N was established as 2'-O-methyl-5-formylcytidine (f5CM), and its reduced derivative as 2'-O-methyl-5-hydroxy-methylcytidine (om5Cm). By sequencing the bovine liver tRNA(Leu), the structure of the anticodon was determined as f5CmAA. In addition, the nucleotide sequence showed two primary structures differing only by the nucleotide 47c which is either uridine or adenosine. The two slightly differing bovine liver tRNAs-Leu(f5CmAA) are the only tRNAs so far sequenced which contain f5Cm. The role of such a modified cytidine at the first position of the anticodon is discussed in terms of decoding properties for the UUG and UUA leucine codons. Recently, precise evidence was obtained for the presence of f5Cm at the same position in tRNAs(Leu)(NAA) isolated from rabbit and lamb liver. Therefore, the 2'-O-methyl-5-formyl modification of cytidine at position 34 could be a general feature of cytoplasmic tRNAs(Leu)(NAA) in mammals. PMID:8628682

PCR analysis of a prescription vegetarian diet and use in three dogs with cutaneous adverse food reactions.

PubMed

Aufox, Erin E; May, Elizabeth R; Frank, Linda A; Kania, Stephen A

2018-04-24

Cutaneous adverse food reaction (CAFR) is diagnosed by performing an elimination diet trial utilizing prescription or home-cooked diets followed by provocative challenge. To report findings of PCR analysis of a prescription vegetarian diet (RCV) for undeclared proteins of animal origin, as well as to describe its utilization for diagnosis and management of dogs suspected of having CAFR. Three client-owned dogs. PCR analysis of RCV for 11 mammalian species and poultry. In three dogs, clinical examination, cytology, aerobic culture (if indicated) and at least one elimination diet trial with RCV. In our case series, all dogs had a history of pruritus and recurrent pyoderma that resolved with infection control and an elimination diet trial. In cases 1 and 2, a diagnosis of CAFR was made following an elimination trial with RCV and provocative challenge. Case 3 had a previously confirmed diagnosis of CAFR and RCV was successfully used to maintain remission of CAFR-related signs. PCR testing of RCV was negative for 11 mammalian species and poultry. The RCV diet was found not to contain any undeclared mammalian or avian proteins. In this case series, the RCV was successfully used to diagnose and maintain three dogs with CAFR. © 2018 ESVD and ACVD.

Gas chromatographic determination of yohimbine in commercial yohimbe products.

PubMed

Betz, J M; White, K D; der Marderosian, A H

1995-01-01

The bark of Pausinystalia yohimbe [K. Schumann] Pierre (Rubiaceae), long valued as an aphrodisiac in West Africa, recently has been promoted in the United States as a dietary supplement alternative to anabolic steroids for enhancement of athletic performance. As the number of yohimbe products on the retail market increases, concerns about their safety are raised because of the reported toxicity of yohimbine (the major alkaloid of the plant). Although plant materials are usually identified microscopically, we were unable to identify them in many of the products, because as their labels indicated, the products were mixtures of various botanicals or were bark extracts and contained little or no plant material. A method for extraction and capillary gas chromatographic (GC) separation of the alkaloids of P. yohimbe was, therefore, developed and used to analyze a number of commercial yohimbe products. The method involved solvent extraction and partitioning in chloroform-water followed by separation on a methyl silicone capillary GC column (N-P detection). Comparisons of chromatograms of extracts of authentic bark with those of commercial products indicated that, although many products contained measurable quantities of the alkaloid yohimbine, they were largely devoid of the other alkaloids previously reported in this species. Concentrations of yohimbine in the commercial products ranged from < 0.1 to 489 ppm, compared with 7089 ppm in the authentic material. Authentic bark has been reported to contain up to 6% total alkaloids, 10-15% of which are yohimbine. The possible presence of undeclared diluents in the products was indicated by peaks in product chromatograms but not in those of authentic bark.

Preparation and Evaluation at the Delta Opioid Receptor of a Series of Linear Leu-Enkephalin Analogues Obtained by Systematic Replacement of the Amides

PubMed Central

2013-01-01

Leu-enkephalin analogues, in which the amide bonds were sequentially and systematically replaced either by ester or N-methyl amide bonds, were prepared using classical organic chemistry as well as solid phase peptide synthesis (SPPS). The peptidomimetics were characterized using competition binding, ERK1/2 phosphorylation, receptor internalization, and contractility assays to evaluate their pharmacological profile over the delta opioid receptor (DOPr). The lipophilicity (LogD7.4) and plasma stability of the active analogues were also measured. Our results revealed that the last amide bond can be successfully replaced by either an ester or an N-methyl amide bond without significantly decreasing the biological activity of the corresponding analogues when compared to Leu-enkephalin. The peptidomimetics with an N-methyl amide function between residues Phe and Leu were found to be more lipophilic and more stable than Leu-enkephalin. Findings from the present study further revealed that the hydrogen-bond donor properties of the fourth amide of Leu-enkephalin are not important for its biological activity on DOPr. Our results show that the systematic replacement of amide bonds by isosteric functions represents an efficient way to design and synthesize novel peptide analogues with enhanced stability. Our findings further suggest that such a strategy can also be useful to study the biological roles of amide bonds. PMID:23650868

Analytical analyses of startup measurements associated with the first use of LEU fuel in Romania`s 14-MW TRIGA reactor

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bretscher, M.M.; Snelgrove, J.L.; Ciocanescu, M.

1992-12-01

The 14-MW TRIGA steady state reactor (SSR) is located in Pitesti, Romania. Beginning with an HEU core (10 wt% U), the reactor first went critical in November 1979 but was shut down ten years later because of insufficient excess reactivity. Last November the Institute for Nuclear Research (INR), which operates the SSR, received from the ANL RERTR program a shipment of 125 LEU pins fabricated by General Atomics and of the same geometry as the original fuel but with an enrichment of 19.7% 235U and a loading of 45 wt% U. Using 100 of these pins, four LEU clusters, eachmore » containing a 5 x 5 square array of fuel rods, were assembled. These four LEU clusters replaced the four most highly burned HEU elements in the SSR. The reactor resumed operations last February with a 35-element mixed HEU/LEU core configuration. In preparation for full power operation of the SSR with this mixed HEU/LEU core, a number of measurements were made. These included control rod calibrations, excess reactivity determinations, worths of experiment facilities, reaction rate distributions, and themocouple measurements of fuel temperatures as a function of reactor power. This paper deals with a comparison of some of these measured reactor parameters with corresponding analytical calculations.« less

Enkephalinase inhibitor potentiates substance P- and electrically induced contraction in ferret trachea.

PubMed

Sekizawa, K; Tamaoki, J; Nadel, J A; Borson, D B

1987-10-01

To determine the role of endogenous enkephalinase (EC 3.4.24.11) in regulating peptide-induced contraction of airway smooth muscle, we studied the effect of the enkephalinase inhibitor, leucine-thiorphan (Leu-thiorphan), on responses of isolated ferret tracheal smooth muscle segments to substance P (SP) and to electrical field stimulation (EFS). Leu-thiorphan shifted the dose-response curve to SP to lower concentrations. Atropine or the SP antagonist [D-Pro2,D-Trp7,9]SP significantly inhibited SP-induced contractions in the presence of Leu-thiorphan. Leu-thiorphan increased the contractile responses to EFS dose dependently, an effect that was significantly inhibited by the SP antagonist [D-Pro2,D-Trp7,9]SP. SP, in a concentration that did not cause contraction, increased the contractile responses to EFS. This effect was augmented by Leu-thiorphan dose dependently and was not inhibited by hexamethonium or by phentolamine but was inhibited by atropine. Because contractile responses to acetylcholine were not significantly affected by SP or by Leu-thiorphan, the potentiating effects of SP were probably on presynaptic-postganglionic cholinergic neurotransmission. Captopril, bestatin, or leupeptin did not augment contractions, suggesting that enkephalinase was responsible for the effects. These results suggest that endogenous tachykinins modulate smooth muscle contraction and endogenous enkephalinase modulates contractions produced by endogenous or exogenous tachykinins and tachykinin-induced facilitation of cholinergic neurotransmission.

Role of tryptophan 95 in substrate specificity and structural stability of Sulfolobus solfataricus alcohol dehydrogenase.

PubMed

Pennacchio, Angela; Esposito, Luciana; Zagari, Adriana; Rossi, Mosè; Raia, Carlo A

2009-09-01

A mutant of the thermostable NAD(+)-dependent (S)-stereospecific alcohol dehydrogenase from Sulfolobus solfataricus (SsADH) which has a single substitution, Trp95Leu, located at the substrate binding pocket, was fully characterized to ascertain the role of Trp95 in discriminating between chiral secondary alcohols suggested by the wild-type SsADH crystallographic structure. The Trp95Leu mutant displays no apparent activity with short-chain primary and secondary alcohols and poor activity with aromatic substrates and coenzyme. Moreover, the Trp --> Leu substitution affects the structural stability of the archaeal ADH, decreasing its thermal stability without relevant changes in secondary structure. The double mutant Trp95Leu/Asn249Tyr was also purified to assist in crystallographic analysis. This mutant exhibits higher activity but decreased affinity toward aliphatic alcohols, aldehydes as well as NAD(+) and NADH compared to the wild-type enzyme. The crystal structure of the Trp95Leu/Asn249Tyr mutant apo form, determined at 2.0 A resolution, reveals a large local rearrangement of the substrate site with dramatic consequences. The Leu95 side-chain conformation points away from the catalytic metal center and the widening of the substrate site is partially counteracted by a concomitant change of Trp117 side chain conformation. Structural changes at the active site are consistent with the reduced activity on substrates and decreased coenzyme binding.

Novel activity of angiotensin-converting enzyme. Hydrolysis of cholecystokinin and gastrin analogues with release of the amidated C-terminal dipeptide.

PubMed Central

Dubreuil, P; Fulcrand, P; Rodriguez, M; Fulcrand, H; Laur, J; Martinez, J

1989-01-01

ACE (angiotensin-converting enzyme; peptidyl dipeptidase A; EC 3.4.15.1), cleaves C-terminal dipeptides from active peptides containing a free C-terminus. We investigated the hydrolysis of cholecystokinin-8 [CCK-8; Asp-Tyr(SO3H)-Met-Gly-Trp-Met-Asp-Phe-NH2] and of various gastrin analogues by purified rabbit lung ACE. Although these peptides are amidated at their C-terminal end, they were metabolized by ACE to several peptide fragments. These fragments were analysed by h.p.l.c., isolated and identified by comparison with synthetic fragments, and by amino acid analysis. The initial and major site of hydrolysis was the penultimate peptide bond, which generated a major product, the C-terminal amidated dipeptide Asp-Phe-NH2. As a secondary cleavage, ACE subsequently released di- or tri-peptides from the C-terminal end of the remaining N-terminal fragments. The cleavage of CCK-8 and gastrin analogues was inhibited by ACE inhibitors (Captopril and EDTA), but not by other enzyme inhibitors (phosphoramidon, thiorphan, bestatin etc.). Hydrolysis of [Leu15]gastrin-(14-17)-peptide [Boc (t-butoxycarbonyl)-Trp-Leu-Asp-Phe-NH2] in the presence of ACE was found to be dependent on the chloride-ion concentration. Km values for the hydrolysis of CCK-8, [Leu15]gastrin-(11-17)-peptide and Boc-[Leu15]gastrin-(14-17)-peptide at an NaCl concentration of 300 mM were respectively 115, 420 and 3280 microM, and the catalytic constants were about 33, 115 and 885 min-1. The kcat/Km for the reactions at 37 degrees C was approx. 0.28 microM-1.min-1, which is approx. 35 times less than that reported for the cleavage of angiotensin I. These results suggest that ACE might be involved in the metabolism in vivo of CCK and gastrin short fragments. PMID:2554881

Processing of the Escherichia coli leuX tRNA transcript, encoding tRNA(Leu5), requires either the 3'-->5' exoribonuclease polynucleotide phosphorylase or RNase P to remove the Rho-independent transcription terminator.

PubMed

Mohanty, Bijoy K; Kushner, Sidney R

2010-01-01

Here we report a unique processing pathway in Escherichia coli for tRNA(Leu5) in which the exoribonuclease polynucleotide phosphorylase (PNPase) removes the Rho-independent transcription terminator from the leuX transcript without requiring the RhlB RNA helicase. Our data demonstrate for the first time that PNPase can efficiently degrade an RNA substrate containing secondary structures in vivo. Furthermore, RNase P, an endoribonuclease that normally generates the mature 5'-ends of tRNAs, removes the leuX terminator inefficiently independent of PNPase activity. RNase P cleaves 4-7 nt downstream of the CCA determinant generating a substrate for RNase II, which removes an additional 3-4 nt. Subsequently, RNase T completes the 3' maturation process by removing the remaining 1-3 nt downstream of the CCA determinant. RNase E, G and Z are not involved in terminator removal. These results provide further evidence that the E. coli tRNA processing machinery is far more diverse than previously envisioned.

Structure and receptor-binding activity of insulin from a holostean fish, the bowfin (Amia calva).

PubMed

Conlon, J M; Youson, J H; Whittaker, J

1991-05-15

The holostean fishes are the extant representatives of the primitive ray-finned fishes from which the present-day teleosts may have evolved. The primary structure of insulin from a holostean fish, the bowfin (Amia calva), was established as: A-chain: Gly-Ile-Val-Glu-Gln-Cys-Cys-Leu-Lys-Pro-Cys-Thr-Ile-Tyr-Glu-Met-Glu- Lys-Tyr-Cys-Asn B-chain: Ala-Ala-Ser-Gln-His-Leu-Cys-Gly-Ser-His-Leu-Val-Glu-Ala-Leu-Phe-Leu- Val-Cys-Gly-Glu-Ser-Gly-Phe-Phe-Tyr-Asn-Pro-Asn-Lys-Ser This amino acid sequence contains several substitutions (methionine at A16, phenylalanine at B16 and serine at B22) at sites that have been strongly conserved in other vertebrate species and that may be expected to influence biological activity. Consistent with this prediction, bowfin insulin was approx. 14-fold less potent than pig insulin in inhibiting the binding of [125I-Tyr-A14](human insulin) to transfected mouse NIH 3T3 cells expressing the human insulin receptor.

Structure and receptor-binding activity of insulin from a holostean fish, the bowfin (Amia calva).

PubMed Central

Conlon, J M; Youson, J H; Whittaker, J

1991-01-01

The holostean fishes are the extant representatives of the primitive ray-finned fishes from which the present-day teleosts may have evolved. The primary structure of insulin from a holostean fish, the bowfin (Amia calva), was established as: A-chain: Gly-Ile-Val-Glu-Gln-Cys-Cys-Leu-Lys-Pro-Cys-Thr-Ile-Tyr-Glu-Met-Glu- Lys-Tyr-Cys-Asn B-chain: Ala-Ala-Ser-Gln-His-Leu-Cys-Gly-Ser-His-Leu-Val-Glu-Ala-Leu-Phe-Leu- Val-Cys-Gly-Glu-Ser-Gly-Phe-Phe-Tyr-Asn-Pro-Asn-Lys-Ser This amino acid sequence contains several substitutions (methionine at A16, phenylalanine at B16 and serine at B22) at sites that have been strongly conserved in other vertebrate species and that may be expected to influence biological activity. Consistent with this prediction, bowfin insulin was approx. 14-fold less potent than pig insulin in inhibiting the binding of [125I-Tyr-A14](human insulin) to transfected mouse NIH 3T3 cells expressing the human insulin receptor. PMID:2039477

Identification of a hepatoprotective peptide in wheat gluten hydrolysate against D-galactosamine-induced acute hepatitis in rats.

PubMed

Sato, Kenji; Egashira, Yukari; Ono, Shin; Mochizuki, Satoshi; Shimmura, Yuki; Suzuki, Yoshio; Nagata, Megumi; Hashimoto, Kaori; Kiyono, Tamami; Park, Eun Young; Nakamura, Yasushi; Itabashi, Mariko; Sakata, Yuka; Furuta, Seigo; Sanada, Hiroo

2013-07-03

A hepatoprotective peptide, pyroglutamyl leucine (pyroGlu-Leu), was identified in wheat gluten hydrolysate through an in vivo activity-guided fractionation approach based on D-galactosamine-induced acute hepatitis in rats and fractionation of peptides with large-scale preparative ampholine-free isoelectric focusing. The active acidic fraction predominantly consisted of pyroglutamyl peptides and free pyroglutamic acid. Pyroglutamyl peptides were derivatized with phenyl isothiocyanate after removal of a pyroglutamyl residue by pyroglutamate aminopeptidase. The derivatives were purified by reversed-phase HPLC and subjected to sequence analysis. The active fraction contained pyroGlu-Ile, pyroGlu-Leu, pyroGlu-Gln, pyroGlu-Gln-Gln, and free pyroGlu. Ingestion of pyroGlu-Leu at 20 mg/kg body weight significantly decreased serum aspartate and alanine aminotransferases to approximately 30% and 20% of those values of the vehicle group, respectively, which were near the normal levels. Thirty minutes after ingestion of pyroGlu-Leu at 20 mg/kg, the concentration of pyroGlu-Leu in portal blood plasma increased to approximately 2 μM.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Brunett, A. J.; Fei, T.; Strons, P. S.

The Transient Reactor Test Facility (TREAT), located at Idaho National Laboratory (INL), is a test facility designed to evaluate the performance of reactor fuels and materials under transient accident conditions. The facility, an air-cooled, graphite-moderated reactor designed to utilize fuel containing high-enriched uranium (HEU), has been in non-operational standby status since 1994. Currently, in support of the missions of the Department of Energy (DOE) National Nuclear Security Administration (NNSA) Material Management and Minimization (M3) Reactor Conversion Program, a new core design is being developed for TREAT that will utilize low-enriched uranium (LEU). The primary objective of this conversion effort ismore » to design an LEU core that is capable of meeting the performance characteristics of the existing HEU core. Minimal, if any, changes are anticipated for the supporting systems (e.g. reactor trip system, filtration/cooling system, etc.); therefore, the LEU core must also be able to function with the existing supporting systems, and must also satisfy acceptable safety limits. In support of the LEU conversion effort, a range of ancillary safety analyses are required to evaluate the LEU core operation relative to that of the existing facility. These analyses cover neutronics, shielding, and thermal hydraulic topics that have been identified as having the potential to have reduced safety margins due to conversion to LEU fuel, or are required to support the required safety analyses documentation. The majority of these ancillary tasks have been identified in [1] and [2]. The purpose of this report is to document the ancillary safety analyses that have been performed at Argonne National Laboratory during the early stages of the LEU design effort, and to describe ongoing and anticipated analyses. For all analyses presented in this report, methodologies are utilized that are consistent with, or improved from, those used in analyses for the HEU Final Safety Analysis Report (FSAR) [3]. Depending on the availability of historical data derived from HEU TREAT operation, results calculated for the LEU core are compared to measurements obtained from HEU TREAT operation. While all analyses in this report are largely considered complete and have been reviewed for technical content, it is important to note that all topics will be revisited once the LEU design approaches its final stages of maturity. For most safety significant issues, it is expected that the analyses presented here will be bounding, but additional calculations will be performed as necessary to support safety analyses and safety documentation. It should also be noted that these analyses were completed as the LEU design evolved, and therefore utilized different LEU reference designs. Preliminary shielding, neutronic, and thermal hydraulic analyses have been completed and have generally demonstrated that the various LEU core designs will satisfy existing safety limits and standards also satisfied by the existing HEU core. These analyses include the assessment of the dose rate in the hodoscope room, near a loaded fuel transfer cask, above the fuel storage area, and near the HEPA filters. The potential change in the concentration of tramp uranium and change in neutron flux reaching instrumentation has also been assessed. Safety-significant thermal hydraulic items addressed in this report include thermally-induced mechanical distortion of the grid plate, and heating in the radial reflector.« less

Dietary tryptophan depletion in humans using a simplified two amino acid formula - a pilot study.

PubMed

Linden, Maike; Helmbold, Katrin; Kempf, Janina; Sippas, Shabnam; Filss, Christian; Langen, Karl-Josef; Eisert, Albrecht; Zepf, Florian Daniel

2016-01-01

Acute tryptophan depletion (ATD) is a well-established dietary method in translational brain research used to briefly lower central nervous serotonin (5-hydroxytryptamine (5-HT)) synthesis. A simplified two amino acid ATD formula (ATD PHE/LEU ) was developed while reducing the overall amount of amino acids (AAs), with the objective of administration especially in children and adolescents in future studies. This study investigated tryptophan (TRP) influx rates across the blood-brain barrier (BBB) after dietary ATD PHE/LEU administration relative to the ATD Moja-De protocol that has been established for use in children and adolescents. Seventy-two healthy adults (50% females) were randomized into four groups and administered ATD Moja-De, its TRP-balanced control condition (BAL), ATD PHE/LEU , or its respective control mixture (BAL PHE/LEU ) in a counterbalanced, double-blind, between-subjects design. Blood samples were collected at baseline and at hourly intervals for 6 h after AA intake. Questionnaires about mood, taste, and challenge tolerance were completed at fixed time points. Both challenge mixtures significantly reduced central nervous TRP influx as calculated by Michaelis-Menten kinetics relative to baseline and the respective control conditions with only mild and comparable side effects. A greater decline in TRP influx over the BBB after ATD PHE/LEU administration when compared with ATD Moja-De was detected without group effects for taste, challenge tolerance, and mood. There was unintended initial short increase in plasma TRP concentrations observed after ATD PHE/LEU intake, and a possible redistribution between free and protein-bound TRP triggered by protein synthesis stimulated by the ingested AAs may account for this finding. Moreover, a decline in TRP influx after BAL PHE/LEU administration over a 6-h period was observed, and the large amount of PHE in the BAL PHE/LEU mixture may be a possible explanation for this particular phenomenon, which could have led to an unexpected increase in displacement of TRP at the BBB in this control condition. This pilot study provides preliminary evidence for the possibility of lowering TRP influx as calculated by Michaelis-Menten kinetics into the brain by using a simplified ATD protocol in humans. The simplified composition of only two AAs, the lower overall AA amount, and the appropriate tolerance are characteristics of the newly developed ATD PHE/LEU protocol. Future studies focusing on the effects of the ATD PHE/LEU protocol and its respective control condition on CSF 5-HIAA concentrations, as well as neurochemical studies in rodents, are needed to further validate this newly developed AA mixture before definite conclusions about its usability in ATD-related research in humans, its specificity, and additional effects can be made.

ATR LEU Fuel and Burnable Absorber Neutronics Performance Optimization by Fuel Meat Thickness Variation

DOE Office of Scientific and Technical Information (OSTI.GOV)

G. S. Chang

2007-09-01

The Advanced Test Reactor (ATR) is a high power density and high neutron flux research reactor operating in the United States. Powered with highly enriched uranium (HEU), the ATR has a maximum thermal power rating of 250 MWth. Because of the large test volumes located in high flux areas, the ATR is an ideal candidate for assessing the feasibility of converting an HEU driven reactor to a low-enriched core. The present work investigates the necessary modifications and evaluates the subsequent operating effects of this conversion. A detailed plate-by-plate MCNP ATR 1/8th core model was developed and validated for a fuelmore » cycle burnup comparison analysis. Using the current HEU U 235 enrichment of 93.0 % as a baseline, an analysis can be performed to determine the low-enriched uranium (LEU) density and U-235 enrichment required in the fuel meat to yield an equivalent K-eff between the HEU core and the LEU core versus effective full power days (EFPD). The MCNP ATR 1/8th core model will be used to optimize the U-235 loading in the LEU core, such that the differences in K-eff and heat flux profile between the HEU and LEU core can be minimized. The depletion methodology MCWO was used to calculate K-eff versus EFPDs in this paper. The MCWO-calculated results for the LEU cases with foil (U-10Mo) types demonstrated adequate excess reactivity such that the K-eff versus EFPDs plot is similar to the reference ATR HEU case. Each HEU fuel element contains 19 fuel plates with a fuel meat thickness of 0.508 mm. In this work, the proposed LEU (U-10Mo) core conversion case with a nominal fuel meat thickness of 0.508 mm and the same U-235 enrichment (15.5 wt%) can be used to optimize the radial heat flux profile by varying the fuel plate thickness from 0.254 to 0.457 mm at the inner 4 fuel plates (1-4) and outer 4 fuel plates (16-19). In addition, a 0.7g of burnable absorber Boron-10 was added in the inner and outer plates to reduce the initial excess reactivity, and the inner/outer heat flux more effectively. The optimized LEU relative radial fission heat flux profile is bounded by the reference ATR HEU case. However, to demonstrate that the LEU core fuel cycle performance can meet the Updated Final Safety Analysis Report (UFSAR) safety requirements, additional studies will be necessary to evaluate and compare safety parameters such as void reactivity and Doppler coefficients, control components worth (outer shim control cylinders, safety rods and regulating rod), and shutdown margins between the HEU and LEU cores.« less

Plasma amino acids and metabolic profiling of dairy cows in response to a bolus duodenal infusion of leucine.

PubMed

Sadri, Hassan; von Soosten, Dirk; Meyer, Ulrich; Kluess, Jeannette; Dänicke, Sven; Saremi, Behnam; Sauerwein, Helga

2017-01-01

Leucine (Leu), one of the three branch chain amino acids, acts as a signaling molecule in the regulation of overall amino acid (AA) and protein metabolism. Leucine is also considered to be a potent stimulus for the secretion of insulin from pancreatice β-cells. Our objective was to study the effects of a duodenal bolus infusion of Leu on insulin and glucagon secretion, on plasma AA concentrations, and to do a metabolomic profiling of dairy cows as compared to infusions with either glucose or saline. Six duodenum-fistulated Holstein cows were studied in a replicated 3 × 3 Latin square design with 3 periods of 7 days, in which the treatments were applied at the end of each period. The treatments were duodenal bolus infusions of Leu (DIL; 0.15 g/kg body weight), glucose (DIG; at Leu equimolar dosage) or saline (SAL). On the day of infusion, the treatments were duodenally infused after 5 h of fasting. Blood samples were collected at -15, 0, 10, 20, 30, 40, 50, 60, 75, 90, 120, 180, 210, 240 and 300 min relative to the start of infusion. Blood plasma was assayed for concentrations of insulin, glucagon, glucose and AA. The metabolome was also characterized in selected plasma samples (i.e. from 0, 50, and 120 min relative to the infusion). Body weight, feed intake, milk yield and milk composition were recorded throughout the experiment. The Leu infusion resulted in significant increases of Leu in plasma reaching 20 and 15-fold greater values than that in DIG and SAL, respectively. The elevation of plasma Leu concentrations after the infusion led to a significant decrease (P<0.05) in the plasma concentrations of isoleucine, valine, glycine, and alanine. In addition, the mean concentrations of lysine, methionine, phenylalanine, proline, serine, taurine, threonine, and asparagine across all time-points in plasma of DIL cows were reduced (P<0.05) compared with the other groups. In contrast to the working hypothesis about an insulinotropic effect of Leu, the circulating concentrations of insulin were not affected by Leu. In DIG, insulin and glucose concentrations peaked at 30-40 and 40-50 min after the infusion, respectively. Insulin concentrations were greater (P<0.05) from 30-40 min in DIG than DIL and SAL, and glucose was elevated in DIG over DIL and SAL from 30-75 min and 40-50 min, respectively. Multivariate metabolomics data analysis (principal component analysis and partial least squares discriminant analysis) revealed a clear separation when the DIL cows were compared with the DIG and SAL cows at 50 and 120 min after the infusion. By using this analysis, several metabolites, mainly acylcarnitines, methionine sulfoxide and components from the kynurenine pathway were identified as the most relevant for separating the treatment groups. These results suggest that Leu regulates the plasma concentrations of branched-chain AA, and other AA, apparently by stimulating their influx into the cells from the circulation. A single-dose duodenal infusion of Leu did not elicit an apparent insulin response, but affected multiple intermediary metabolic pathways including AA and energy metabolism by mechanisms yet to be elucidated.

Towards Understanding the Tandem Mass Spectra of Protonated Oligopeptides. 2: The Proline Effect in Collision-Induced Dissociation of Protonated Ala-Ala-Xxx-Pro-Ala (Xxx = Ala, Ser, Leu, Val, Phe, and Trp)

NASA Astrophysics Data System (ADS)

Bleiholder, Christian; Suhai, Sándor; Harrison, Alex G.; Paizs, Béla

2011-06-01

The product ion spectra of proline-containing peptides are commonly dominated by y n ions generated by cleavage at the N-terminal side of proline residues. This proline effect is investigated in the current work by collision-induced dissociation (CID) of protonated Ala-Ala-Xxx-Pro-Ala (Xxx includes Ala, Ser, Leu, Val, Phe, and Trp) in an electrospray/quadrupole/time-of-flight (QqTOF) mass spectrometer and by quantum chemical calculations on protonated Ala-Ala-Ala-Pro-Ala. The CID spectra of all investigated peptides show a dominant y 2 ion (Pro-Ala sequence). Our computational results show that the proline effect mainly arises from the particularly low threshold energy for the amide bond cleavage N-terminal to the proline residue, and from the high proton affinity of the proline-containing C-terminal fragment produced by this cleavage. These theoretical results are qualitatively supported by the experimentally observed y 2 / b 3 abundance ratios for protonated Ala-Ala-Xxx-Pro-Ala (Xxx = Ala, Ser, Leu, Val, Phe, and Trp). In the post-cleavage phase of fragmentation the N-terminal oxazolone fragment with the Ala-Ala-Xxx sequence and Pro-Ala compete for the ionizing proton for these peptides. As the proton affinity of the oxazolone fragment increases, the y 2 / b 3 abundance ratio decreases.

Evidence for differential activation of arachidonic acid metabolism in formylpeptide- and macrophage-activation-factor-stimulated guinea-pig macrophages.

PubMed Central

Homma, Y; Hashimoto, T; Nagai, Y; Takenawa, T

1985-01-01

Alterations of phospholipid and arachidonic acid metabolism were studied by treatment of guinea-pig peritoneal-exudate macrophages with chemotactic peptide, formylmethionyl-leucylphenylalanine (fMet-Leu-Phe) and macrophage activation factor (MAF). The chemotactic peptide caused a rapid rearrangement in inositol phospholipids, including a breakdown of polyphosphoinositides within 30s, followed by a resultant formation of phosphatidylinositol (PI), diacylglycerol, phosphatidic acid and non-esterified arachidonic acid within 5 min. In addition to these sequential alterations, arachidonic acid was released mainly from PI. On the other hand, MAF induced a slow liberation of arachidonic acid, mainly from phosphatidylethanolamine (PE) and phosphatidylcholine (PC) by phospholipase A2 after the incubation period of 30 min, but not any rapid changes in phospholipids. Treatment of macrophages for 15 min with fMet-Leu-Phe produced the leukotrienes (LTs) B4, C4 and D4, prostaglandins (PG) E2 and F2 alpha and thromboxane (TX) B2. In contrast, MAF could not stimulate the production of arachidonic acid metabolites during the incubation period of 15 min, but could enhance that of PGE2, PGF2 alpha, TXB2 and hydroxyeicosatetraenoic acids at 6 h. However, the stimulated formation of LTs was not detected at any time. These results indicate that the effects of fMet-Leu-Phe on both phospholipid and arachidonic acid metabolism are very different from those mediated by MAF. PMID:3931627

Towards understanding the tandem mass spectra of protonated oligopeptides. 2: The proline effect in collision-induced dissociation of protonated Ala-Ala-Xxx-Pro-Ala (Xxx = Ala, Ser, Leu, Val, Phe, and Trp).

PubMed

Bleiholder, Christian; Suhai, Sándor; Harrison, Alex G; Paizs, Béla

2011-06-01

The product ion spectra of proline-containing peptides are commonly dominated by y(n) ions generated by cleavage at the N-terminal side of proline residues. This proline effect is investigated in the current work by collision-induced dissociation (CID) of protonated Ala-Ala-Xxx-Pro-Ala (Xxx includes Ala, Ser, Leu, Val, Phe, and Trp) in an electrospray/quadrupole/time-of-flight (QqTOF) mass spectrometer and by quantum chemical calculations on protonated Ala-Ala-Ala-Pro-Ala. The CID spectra of all investigated peptides show a dominant y(2) ion (Pro-Ala sequence). Our computational results show that the proline effect mainly arises from the particularly low threshold energy for the amide bond cleavage N-terminal to the proline residue, and from the high proton affinity of the proline-containing C-terminal fragment produced by this cleavage. These theoretical results are qualitatively supported by the experimentally observed y(2)/b(3) abundance ratios for protonated Ala-Ala-Xxx-Pro-Ala (Xxx = Ala, Ser, Leu, Val, Phe, and Trp). In the post-cleavage phase of fragmentation the N-terminal oxazolone fragment with the Ala-Ala-Xxx sequence and Pro-Ala compete for the ionizing proton for these peptides. As the proton affinity of the oxazolone fragment increases, the y(2)/b(3) abundance ratio decreases.

Antifouling Activity towards Mussel by Small-Molecule Compounds from a Strain of Vibrio alginolyticus Bacterium Associated with Sea Anemone Haliplanella sp.

PubMed

Wang, Xiang; Huang, Yanqiu; Sheng, Yanqing; Su, Pei; Qiu, Yan; Ke, Caihuan; Feng, Danqing

2017-03-28

Mussels are major fouling organisms causing serious technical and economic problems. In this study, antifouling activity towards mussel was found in three compounds isolated from a marine bacterium associated with the sea anemone Haliplanella sp. This bacterial strain, called PE2, was identified as Vibrio alginolyticus using morphology, biochemical tests, and phylogenetic analysis based on sequences of 16S rRNA and four housekeeping genes ( rpoD, gyrB, rctB, and toxR ). Three small-molecule compounds (indole, 3-formylindole, and cyclo (Pro-Leu)) were purified from the ethyl acetate extract of V. alginolyticus PE2 using column chromatography techniques. They all significantly inhibited byssal thread production of the green mussel Perna viridis , with EC 50 values of 24.45 μg/ml for indole, 50.07 μg/ml for 3-formylindole, and 49.24 μg/ml for cyclo (Pro-Leu). Previous research on the antifouling activity of metabolites from marine bacteria towards mussels is scarce. Indole, 3-formylindole and cyclo (Pro-Leu) also exhibited antifouling activity against settlement of the barnacle Balanus albicostatus (EC 50 values of 8.84, 0.43, and 11.35 μg/ml, respectively) and the marine bacterium Pseudomonas sp. (EC 50 values of 42.68, 69.68, and 39.05 μg/ml, respectively). These results suggested that the three compounds are potentially useful for environmentally friendly mussel control and/or the development of new antifouling additives that are effective against several biofoulers.

Status of French reactors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ballagny, A.

1997-08-01

The status of French reactors is reviewed. The ORPHEE and RHF reactors can not be operated with a LEU fuel which would be limited to 4.8 g U/cm{sup 3}. The OSIRIS reactor has already been converted to LEU. It will use U{sub 3}Si{sub 2} as soon as its present stock of UO{sub 2} fuel is used up, at the end of 1994. The decision to close down the SILOE reactor in the near future is not propitious for the start of a conversion process. The REX 2000 reactor, which is expected to be commissioned in 2005, will use LEU (exceptmore » if the fast neutrons core option is selected). Concerning the end of the HEU fuel cycle, the best option is reprocessing followed by conversion of the reprocessed uranium to LEU.« less

Characterization of an antibiotic produced by Bacillus subtilis JW-1 that suppresses Ralstonia solanacearum.

PubMed

Kwon, Jae Won; Kim, Shin Duk

2014-01-01

Bacillus subtilis JW-1 was isolated from rhizosphere soil as a potential biocontrol agent of bacterial wilt caused by Ralstonia solanacearum. Seed treatment followed by a soil drench application with this strain resulted in >80% reduction in bacterial wilt disease compared with that in the untreated control under greenhouse conditions. The antibacterial compound produced by strain JW-1 was purified by bioactivity-guided fractionation. Based on mass spectroscopy and nuclear magnetic resonance spectral data ((1)H, (13)C, (1)H-(1)H correlation spectroscopies, rotating frame nuclear Overhauser effect spectroscopy, and heteronuclear multiple-bond correlation spectroscopy), the structure of this compound was elucidated as a cyclic lipopeptide composed of a heptapeptide (Gln-Leu-Leu-Val-Asp-Leu-Leu) bonded to a β-hydroxy-iso-hexadecanoic acid arranged in a lactone ring system.

Novel angiotensin I-converting enzyme inhibitory peptides isolated from Alcalase hydrolysate of mung bean protein.

PubMed

Li, Guan-Hong; Wan, Ju-Zhen; Le, Guo-Wei; Shi, Yong-Hui

2006-08-01

Mung bean protein isolates were hydrolyzed for 2 h by Alcalase. The generated hydrolysate showed angiotensin I-converting enzyme (ACE) inhibitory activity with the IC(50) value of 0.64 mg protein/ml. Three kinds of novel ACE inhibitory peptides were isolated from the hydrolysate by Sephadex G-15 and reverse-phase high performance liquid chromatography (RP-HPLC). These peptides were identified by amino acid composition analysis and matrix assisted-laser desorption/ionization time-of-flight tandem mass spectrometry (MALDI-TOF MS/MS), as Lys-Asp-Tyr-Arg-Leu, Val-Thr-Pro-Ala-Leu-Arg and Lys-Leu-Pro-Ala-Gly-Thr-Leu-Phe with the IC(50) values of 26.5 microM, 82.4 microM and 13.4 microM, respectively. Copyright (c) 2006 European Peptide Society and John Wiley & Sons, Ltd.

Raman and surface enhanced Raman spectroscopy of amino acids and peptide

NASA Astrophysics Data System (ADS)

Yuan, Xiaojuan; Gu, Huaimin; Wu, Jiwei; Kang, Jian; Dong, Xiao

2009-08-01

Surface enhanced Raman scattering (SERS) is potentially tool in the characterization of biomolecules such as amino acids, complicated peptides and proteins, and even tissues or living cells. Amino acids and short peptides contain different functional groups. Therefore, they are suitable for the investigations of the competitive-interactions of these functional groups with colloidal silver surfaces. In this paper, Normal Raman and SERS of amino acids Leucine and Isoleucine and short peptide Leu-Leu were measured on the silver colloidal substrate. Raman shifts that stem from different vibrational mode in the molecular inner structure, and the variations of SERS of the samples were analyzed in this study. The results show that different connection of one methyl to the main chains of the isomer amino acids resulted in different vibration modes in the Normal Raman spectra of Leucine and Isoleucine. In the SERS spectra of the isomer amino acids, all frequency shifts are expressed more differently than those in Normal Raman spectra of solid state. Orientation of this isomer amino acids, as well as specific-competitive interactions of their functional groups with the colloidal silver surface, were speculated by detailed spectral analysis of the obtained SERS spectra. In addition, the dipeptide Leu-Leu, as the corresponding homodipeptide of Leucine, was also measured adsorbed on the colloidal silver surface. The SERS spectrum of Leu-Leu is different from its corresponding amino acid Leucine but both of them are adsorbed on the silver surface through the carboxylate moiety.

Leu72Met408 Polymorphism of the Ghrelin Gene Is Associated With Early Phase of Gastric Emptying in the Patients With Functional Dyspepsia in Japan

PubMed Central

Yamawaki, Hiroshi; Futagami, Seiji; Shimpuku, Mayumi; Shindo, Tomotaka; Maruki, Yuuta; Nagoya, Hiroyuki; Kodaka, Yasuhiro; Sato, Hitomi; Gudis, Katya; Kawagoe, Tetsuro; Sakamoto, Choitsu

2015-01-01

Background/Aims There are no available data about the relationship between ghrelin gene genotypes and early phase of gastric emptying in functional dyspepsia (FD) as defined by Rome III classification. Methods We enrolled 74 patients presenting with typical symptoms of FD and 64 healthy volunteers. Gastric motility was evaluated using the 13C-acetate breath test. We used Rome III criteria to evaluate upper abdominal symptoms and self-rating questionnaires for depression (SRQ-D) scores to determine status of depression. The Arg51Gln (346G>A), preproghrelin (3056T>C), Leu72Met (408C>A), Gln90Leu (3412T>A) and G-protein β3 (825C>T) polymorphisms were analyzed in the DNA from blood samples of enrolled subjects. Genotyping was performed by polymerase chain reaction. Results There was a significant relationship between the Gln90Leu3412 genotype and SRQ-D score in FD patients (P = 0.009). Area under the curve at 15 minutes (AUC15) value was significantly associated with the Leu72Met408 genotype (P = 0.015) but not with entire gastric emptying. Conclusions The Leu72Met (408C>A) single nucleotide polymorphism was significantly associated with early phase of gastric emptying in FD patients. Further studies will be necessary to clarify the association between ghrelin gene single nucleotide polymorphisms and early phase of gastric emptying in FD patients. PMID:25540946

The Leu72Met polymorphism of the ghrelin gene is associated with a decreased risk for type 2 diabetes.

PubMed

Berthold, Heiner K; Giannakidou, Eleni; Krone, Wilhelm; Mantzoros, Christos S; Gouni-Berthold, Ioanna

2009-01-01

Ghrelin is involved in several metabolic and cardiovascular processes. The Leu72Met polymorphism of its gene was associated with an increased risk of type 2 diabetes (DM2) in some, but not all studies. Its association with atherosclerosis is not known. We investigated 420 Caucasian subjects with DM2 and 430 controls without diabetes (56.6% male, age 62+/-10 years). The Leu72Leu genotype frequencies were 89.76/84.65%, the Leu72Met 9.52/15.12% and the Met72Met 0.71/0.23% (P=0.029) in the DM2 and controls groups, respectively. In subjects with Met72+ genotypes the risk of DM2 was significantly decreased (univariate OR 0.63, 95% CI 0.42-0.95, P=0.026). In a logistic regression model, body mass index, hypertension and a positive family history for diabetes were predictors of diabetes while the polymorphism remained negatively associated with the disease (OR 0.62, 95% CI 0.40-0.97, P=0.036). After adjusting for known risk factors for atherosclerosis, the Met72+ variant was not associated with atherosclerotic disease (OR 1.41, 95% CI 0.78-2.54, P=0.25). Ghrelin concentrations were not associated with the polymorphism, DM2 or atherosclerotic disease. The Leu72Met polymorphism of the ghrelin gene is associated with a decreased risk for DM2. There is no association between the variant and atherosclerotic disease or ghrelin concentrations.

Leu72Met408 Polymorphism of the Ghrelin Gene Is Associated With Early Phase of Gastric Emptying in the Patients With Functional Dyspepsia in Japan.

PubMed

Yamawaki, Hiroshi; Futagami, Seiji; Shimpuku, Mayumi; Shindo, Tomotaka; Maruki, Yuuta; Nagoya, Hiroyuki; Kodaka, Yasuhiro; Sato, Hitomi; Gudis, Katya; Kawagoe, Tetsuro; Sakamoto, Choitsu

2015-01-01

There are no available data about the relationship between ghrelin gene genotypes and early phase of gastric emptying in functional dyspepsia (FD) as defined by Rome III classification. We enrolled 74 patients presenting with typical symptoms of FD and 64 healthy volunteers. Gastric motility was evaluated using the 13C-acetate breath test. We used Rome III criteria to evaluate upper abdominal symptoms and self-rating questionnaires for depression (SRQ-D) scores to determine status of depression. The Arg51Gln (346G->A), preproghrelin (3056T->C), Leu72Met (408C->A), Gln90Leu (3412T->A) and G-protein 3 (825C->T) polymorphisms were analyzed in the DNA from blood samples of enrolled subjects. Genotyping was performed by polymerase chain reaction. There was a significant relationship between the Gln90Leu3412 genotype and SRQ-D score in FD patients (P = 0.009). Area under the curve at 15 minutes (AUC15) value was significantly associated with the Leu72Met408 genotype (P = 0.015) but not with entire gastric emptying. The Leu72Met (408C->A) single nucleotide polymorphism was significantly associated with early phase of gastric emptying in FD patients. Further studies will be necessary to clarify the association between ghrelin gene single nucleotide polymorphisms and early phase of gastric emptying in FD patients.

A GTPase reaction accompanying the rejection of Leu-tRNA2 by UUU-programmed ribosomes. Proofreading of the codon-anticodon interaction by ribosomes.

PubMed

Thompson, R C; Dix, D B; Gerson, R B; Karim, A M

1981-01-10

The characteristics of a GTPase reaction between poly(U)-programmed ribosomes, EFTu . GTP, and the near-cognate aminoacyl (aa)-tRNA, Leu-tRNA Leu 2, have been studied to assess the role of this reaction in proofreading of the codon-anticodon interaction. The reaction resembles the GTPase reaction with cognate aa-tRNAs and EFTu . GTP in its substrate requirements, in its involving EFTu . GTP . aa-tRNA ternary complexes, and in its requiring a free ribosomal A-site. The noncognate reaction differs from the cognate one in that aa-tRNA becomes stably bound to the ribosomes only 5% of the time; it therefore seems best characterized as an abortive enzymatic binding reaction. The rate of reaction is a significant fraction (4%) of that of the cognate aa-tRNA, indicating that recognition of ternary complexes by ribosomes involves a level of error greater than that of translation as a whole. The rejection of the noncognate aa-tRNA following GTP hydrolysis is therefore a vital step in the translation process and fulfills the criteria set for a proofreading reaction. Leu-tRNA Leu 2 which escapes rejection through proofreading, forms a stable complex with the ribosomal A-site, so it appears that the Leu-tRNA2 which was rejected never reached the A-site and that proofreading precedes full A-site binding.

Principal Statements of the Defense Emergency Response Fund Financial Statements for FY 1992.

DTIC Science & Technology

1993-06-14

issuance of the reimburs - able orders to the performing activities. 7. The performing activity shall record the receipt of the reimbursable order...to finance DoD’s efforts until the responsible governmental agency or country issues a reimbursable order. Reimbursements for the cost of DoD...relief support during an undeclared major disaster or emergency must be returned to the Fund. All reimbursements and any appropriations deposited to the

Preprints, Impact Factors, and Unethical Behavior, but also Lots of Good News.

PubMed

Gölitz, Peter

2016-10-24

Preprints as well? There is already the Accepted Article (published directly after refereeing and author revision), the Early-View/ASAP-Version (after refereeing, editing and proofing), and the final Version of Record. The problems with preprints are discussed in this Editorial along with the undeclared resubmission of previously rejected manuscripts: publication times, color costs, and Angewandte Symposia are further topics. © 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Stop the Insanity: Halt NATO Enlargement to Salvage Relations with Russia

DTIC Science & Technology

2009-02-12

America’s Undeclared War, 1918 -1920 (Dulles, VA: Brassey’s, 2003), iii. 9 For further discussion of Nazi operations within Russia, see Colonel...2009). 10 against communist authority, by the year’s end Bulgaria, Czechoslovakia, Hungary, Poland and Romania had joined East Germany in...Bucharest, Romania , 4 April 2008, http://www.kremlin.ru/eng/text/speeches/2008/04/04/1949_type82915_163150.shtml (accessed December 2008). 57 Adam

Advanced DNA- and Protein-based Methods for the Detection and Investigation of Food Allergens.

PubMed

Prado, M; Ortea, I; Vial, S; Rivas, J; Calo-Mata, P; Barros-Velázquez, J

2016-11-17

Currently, food allergies are an important health concern worldwide. The presence of undeclared allergenic ingredients or the presence of traces of allergens due to contamination during food processing poses a great health risk to sensitized individuals. Therefore, reliable analytical methods are required to detect and identify allergenic ingredients in food products. The present review addresses the recent developments regarding the application of DNA- and protein-based methods for the detection of allergenic ingredients in foods. The fitness-for-purpose of reviewed methodology will be discussed, and future trends will be highlighted. Special attention will be given to the evaluation of the potential of newly developed and promising technologies that can improve the detection and identification of allergenic ingredients in foods, such as the use of biosensors and/or nanomaterials to improve detection limits, specificity, ease of use, or to reduce the time of analysis. Such rapid food allergen test methods are required to facilitate the reliable detection of allergenic ingredients by control laboratories, to give the food industry the means to easily determine whether its product has been subjected to cross-contamination and, simultaneously, to identify how and when this cross-contamination occurred.

Using a portable ion mobility spectrometer to screen dietary supplements for sibutramine.

PubMed

Dunn, Jamie D; Gryniewicz-Ruzicka, Connie M; Kauffman, John F; Westenberger, Benjamin J; Buhse, Lucinda F

2011-02-20

In response to recent incidents of undeclared sibutramine, an appetite suppressant found in dietary supplements, we developed a method to detect sibutramine using hand-held ion mobility spectrometers with an analysis time of 15 s. Ion mobility spectrometry is a high-throughput and sensitive technique that has been used for illicit drug, explosive, volatile organic compound and chemical warfare detection. We evaluated a hand-held ion mobility spectrometer as a tool for the analysis of supplement extracts containing sibutramine. The overall instrumental limit of detection of five portable ion mobility spectrometers was 2 ng of sibutramine HCl. When sample extractions containing 30 ng/μl or greater of sibutramine were analyzed, saturation of the ionization chamber of the spectrometer occurred and the instrument required more than three cleaning cycles to remove the drug. Hence, supplement samples suspected of containing sibutramine should be prepared at concentrations of 2-20 ng/μl. To obtain this target concentration range for products containing unknown amounts of sibutramine, we provided a simple sample preparation procedure, allowing the U.S. Food and Drug Administration or other agencies to screen products using the portable ion mobility spectrometer. Published by Elsevier B.V.

The Peptide Near the C Terminus Regulates Receptor CAR Nuclear Translocation Induced by Xenochemicals in Mouse Liver

PubMed Central

Zelko, Igor; Sueyoshi, Tatsuya; Kawamoto, Takeshi; Moore, Rick; Negishi, Masahiko

2001-01-01

In response to phenobarbital (PB) and other PB-type inducers, the nuclear receptor CAR translocates to the mouse liver nucleus (T. Kawamoto et al., Mol. Cell. Biol. 19:6318–6322, 1999). To define the translocation mechanism, fluorescent protein-tagged human CAR (hCAR) was expressed in the mouse livers using the in situ DNA injection and gene delivery systems. As in the wild-type hCAR, the truncated receptor lacking the C-terminal 10 residues (i.e., AF2 domain) translocated to the nucleus, indicating that the PB-inducible translocation is AF2 independent. Deletion of the 30 C-terminal residues abolished the receptor translocation, and subsequent site-directed mutagenesis delineated the PB-inducible translocation activity of the receptor to the peptide L313GLL316AEL319. Ala mutations of Leu313, Leu316, or Leu319 abrogated the translocation of CAR in the livers, while those of Leu312 or Leu315 did not affect the nuclear translocation. The leucine-rich peptide dictates the nuclear translocation of hCAR in response to various PB-type inducers and appears to be conserved in the mouse and rat receptors. PMID:11283262

Use of diffusion-ordered NMR spectroscopy and HPLC-UV-SPE-NMR to identify undeclared synthetic drugs in medicines illegally sold as phytotherapies.

PubMed

Silva, Lorena M A; Filho, Elenilson G A; Thomasi, Sérgio S; Silva, Bianca F; Ferreira, Antonio G; Venâncio, Tiago

2013-09-01

The informal (and/or illegal) e-commerce of pharmaceutical formulations causes problems that governmental health agencies find hard to control, one of which concerns formulas sold as natural products. The purpose of this work was to explore the advantages and limitations of DOSY and HPLC-UV-SPE-NMR. These techniques were used to identify the components of a formula illegally marketed in Brazil as an herbal medicine possessing anti-inflammatory and analgesic properties. DOSY was able to detect the major components present at higher concentrations. Complete characterization was achieved using HPLC-UV-SPE-NMR, and 1D and 2D NMR analyses enabled the identification of known synthetic drugs. These were ranitidine and a mixture of orphenadrine citrate, piroxicam, and dexamethasone, which are co-formulated in a remedy called Rheumazim that is used to relieve severe pain, but it is prohibited in Brazil because of a lack of sufficient pharmacokinetic and pharmacodynamic information. Copyright © 2013 John Wiley & Sons, Ltd.

ATR LEU fuel and burnable absorber neutronics performance optimization by fuel meat thickness variation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chang, G.S.

2008-07-15

The Advanced Test Reactor (ATR) is a high power density and high neutron flux research reactor operating in the United States. Powered with highly enriched uranium (HEU), the ATR has a maximum thermal power rating of 250 MWth. Because of the large test volumes located in high flux areas, the ATR is an ideal candidate for assessing the feasibility of converting an HEU driven reactor to a low-enriched core. The present work investigates the necessary modifications and evaluates the subsequent operating effects of this conversion. A detailed plate-by-plate MCNP ATR 1/8th core model was developed and validated for a fuelmore » cycle burnup comparison analysis. Using the current HEU U-235 enrichment of 93.0 % as a baseline, an analysis can be performed to determine the low-enriched uranium (LEU) density and U-235 enrichment required in the fuel meat to yield an equivalent K-eff between the HEU core th and the LEU core versus effective full power days (EFPD). The MCNP ATR 1/8th core model will be used to optimize the U-235 loading in the LEU core, such that the differences in K-eff and heat flux profile between the HEU and LEU core can be minimized. The depletion methodology MCWO was used to calculate K-eff versus EFPDs in this paper. The MCWO-calculated results for the LEU cases with foil (U-10Mo) types demonstrated adequate excess reactivity such that the K-eff versus EFPDs plot is similar to the reference ATR HEU case. Each HEU fuel element contains 19 fuel plates with a fuel meat thickness of 0.508 mm. In this work, the proposed LEU (U-10Mo) core conversion case with a nominal fuel meat thickness of 0.381 mm and the same U-235 enrichment (19.7 wt%) can be used to optimize the radial heat flux profile by varying the fuel meat thickness from 0.191 mm (7.5 mil) to 0.343 mm (13.5 mil) at the inner 4 fuel plates (1-4) and outer 4 fuel plates (16-19). In addition, 0.8g of a burnable absorber, Boron-10, was added in the inner and outer plates to reduce the initial excess reactivity, and the inner/outer heat flux more effectively. The optimized LEU relative radial fission heat flux profile is bounded by the reference ATR HEU case. However, to demonstrate that the LEU core fuel cycle performance can meet the Updated Final Safety Analysis Report (UFSAR) safety requirements, additional studies will be necessary to evaluate and compare safety parameters such as void reactivity and Doppler coefficients, control components worth (outer shim control cylinders, safety rods and regulating rod), and shutdown margins between the HEU and LEU cores. (author)« less

Surface-enhanced Raman difference between bombesin and its modified analogues on the colloidal and electrochemically roughen silver surfaces.

PubMed

Podstawka, Edyta; Ozaki, Yukihiro

2008-10-01

In this article, surface-enhanced Raman scattering (SERS) spectra of bombesin (BN) and its six modified analogues ([D-Phe(12)]BN, [Tyr(4)]BN, [Tyr(4),D-Phe(12)]BN, [D-Phe(12),Leu(14)]BN, [Leu(13)-(R)-Leu(14)]BN, and [Lys(3)]BN) on a colloidal silver surface are reported and compared with SERS spectra of these species immobilized onto an ellectrochemically roughen silver electrode. Changes in enhancement and wavenumber of proper bands upon adsorption on different silver surfaces are consistent with BN and its analogues adsorption primarily through Trp(8). Slightly different adsorption states of these molecules are observed depending upon natural amino acids substitution. For example, the indole ring in all the peptides interacts with silver nanoparticles in a edge-on orientation. It is additionally coordinated to the silver through the N(1)--H bond for all the peptides, except [Phe(12)]BN. This is in contrary to the results obtained for the silver roughen electrode that show direct but not strong N(1)--H/Ag interaction for all peptides except [D-Phe(12),Leu(14)]BN and [Leu(13)-(R)-Leu(14)]BN. For BN only C==O is not involved in the chemical coordination with the colloidal surface. [Lys(3)]BN and BN also adsorb with the C--N bond of NH(2) group normal and horizontal, respectively, to the colloidal surface, whereas C--NH(2) in other peptides is tilted to this surface. Also, the Trp(8) --CH(2)-- moiety of only [Tyr(4)]BN, [Lys(3)]BN, and [Tyr(4),D-Phe(12)]BN coordinates to Ag, whereas the Phe(12) ring of [Phe(12)]BN, [Tyr(4),D-Phe(12)]BN, and [D-Phe(12),Leu(14)]BN assists in the peptides binding only on the colloidal silver. (c) 2008 Wiley Periodicals, Inc.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stillman, J. A.; Feldman, E. E.; Wilson, E. H.

This report contains the results of reactor accident analyses for the University of Missouri Research Reactor (MURR). The calculations were performed as part of the conversion from the use of highly-enriched uranium (HEU) fuel to the use of low-enriched uranium (LEU) fuel. The analyses were performed by staff members of the Global Threat Reduction Initiative (GTRI) Reactor Conversion Program at the Argonne National Laboratory (ANL), the MURR Facility, and the Nuclear Engineering Program – College of Engineering, University of Missouri-Columbia. The core conversion to LEU is being performed with financial support from the U. S. government. This report contains themore » results of reactor accident analyses for the University of Missouri Research Reactor (MURR). The calculations were performed as part of the conversion from the use of highly-enriched uranium (HEU) fuel to the use of low-enriched uranium (LEU) fuel. The analyses were performed by staff members of the Global Threat Reduction Initiative (GTRI) Reactor Conversion Program at the Argonne National Laboratory (ANL), the MURR Facility, and the Nuclear Engineering Program – College of Engineering, University of Missouri-Columbia. The core conversion to LEU is being performed with financial support from the U. S. government. In the framework of non-proliferation policies, the international community presently aims to minimize the amount of nuclear material available that could be used for nuclear weapons. In this geopolitical context most research and test reactors, both domestic and international, have started a program of conversion to the use of LEU fuel. A new type of LEU fuel based on an alloy of uranium and molybdenum (U-Mo) is expected to allow the conversion of U.S. domestic high performance reactors like MURR. This report presents the results of a study of core behavior under a set of accident conditions for MURR cores fueled with HEU U-Alx dispersion fuel or LEU monolithic U-Mo alloy fuel with 10 wt% Mo (U-10Mo).« less

BLENDING LOW ENRICHED URANIUM WITH DEPLETED URANIUM TO CREATE A SOURCE MATERIAL ORE THAT CAN BE PROCESSED FOR THE RECOVERY OF YELLOWCAKE AT A CONVENTIONAL URANIUM MILL

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schutt, Stephen M.; Hochstein, Ron F.; Frydenlund, David C.

2003-02-27

Throughout the United States Department of Energy (DOE) complex, there are a number of streams of low enriched uranium (LEU) that contain various trace contaminants. These surplus nuclear materials require processing in order to meet commercial fuel cycle specifications. To date, they have not been designated as waste for disposal at the DOE's Nevada Test Site (NTS). Currently, with no commercial outlet available, the DOE is evaluating treatment and disposal as the ultimate disposition path for these materials. This paper will describe an innovative program that will provide a solution to DOE that will allow disposition of these materials atmore » a cost that will be competitive with treatment and disposal at the NTS, while at the same time recycling the material to recover a valuable energy resource (yellowcake) for reintroduction into the commercial nuclear fuel cycle. International Uranium (USA) Corporation (IUSA) and Nuclear Fuel Services, Inc. (NFS) have entered into a commercial relationship to pursue the development of this program. The program involves the design of a process and construction of a plant at NFS' site in Erwin, Tennessee, for the blending of contaminated LEU with depleted uranium (DU) to produce a uranium source material ore (USM Ore{trademark}). The USM Ore{trademark} will then be further processed at IUC's White Mesa Mill, located near Blanding, Utah, to produce conventional yellowcake, which can be delivered to conversion facilities, in the same manner as yellowcake that is produced from natural ores or other alternate feed materials. The primary source of feed for the business will be the significant sources of trace contaminated materials within the DOE complex. NFS has developed a dry blending process (DRYSM Process) to blend the surplus LEU material with DU at its Part 70 licensed facility, to produce USM Ore{trademark} with a U235 content within the range of U235 concentrations for source material. By reducing the U235 content to source material levels in this manner, the material will be suitable for processing at a conventional uranium mill under its existing Part 40 license to remove contaminants and enable the product to re-enter the commercial fuel cycle. The tailings from processing the USM Ore{trademark} at the mill will be permanently disposed of in the mill's tailings impoundment as 11e.(2) byproduct material. Blending LEU with DU to make a uranium source material ore that can be returned to the nuclear fuel cycle for processing to produce yellowcake, has never been accomplished before. This program will allow DOE to disposition its surplus LEU and DU in a cost effective manner, and at the same time provide for the recovery of valuable energy resources that would be lost through processing and disposal of the materials. This paper will discuss the nature of the surplus LEU and DU materials, the manner in which the LEU will be blended with DU to form a uranium source material ore, and the legal means by which this blending can be accomplished at a facility licensed under 10 CFR Part 70 to produce ore that can be processed at a conventional uranium mill licensed under 10 CFR Part 40.« less

GC-MS quantitative analysis of black market pharmaceutical products containing anabolic androgenic steroids seized by the Brazilian Federal Police.

PubMed

Neves, Diana Brito da Justa; Caldas, Eloisa Dutra

2017-06-01

The use of counterfeit or substandard medicines can have an important health impact, resulting in therapeutic failure, be toxic or even cause death. Anabolic steroids are a frequent target for counterfeiters worldwide, being the second most frequent counterfeited class in Brazil. The aims of this work were to optimize and validate a GC-MS method for the quantitative determination of anabolic steroids in tablet, aqueous suspension and oil solution forms, and to analyze pharmaceutical products sent to Brazilian Federal Police (BFP) for forensic analysis. Sample preparation included extraction with methanol in ultrasonic bath followed by centrifugation. The method was successfully validated and 345 samples of pharmaceutical products were analyzed (328 medicines and 17 dietary supplements). About 42% of the medicines were counterfeits, 28.7% of tablets, 12.0% of suspensions and 65.2% of oil solutions; 11% were considered substandards. Five dietary supplements contained undeclared anabolic steroids, including two containing methandrostenolone at 5.4 and 5.8mg/capsule, equivalent to levels found in medicines. The proposed method is suitable for implementation in routine analysis for identification of counterfeits and substandard products. The analytical results show the need to raise awareness of consumers over the risks from the consumption of anabolic steroids from the clandestine market and for more incisive actions from government agencies aiming at decreasing the availability of these products. Copyright © 2017 Elsevier B.V. All rights reserved.

Food control and a citizen science approach for improving teaching of Genetics in universities.

PubMed

Borrell, Y J; Muñoz-Colmenero, A M; Dopico, E; Miralles, L; Garcia-Vazquez, E

2016-09-10

A Citizen Science approach was implemented in the laboratory practices of Genetics at the University of Oviedo, related with the engaging topic of Food Control. Real samples of food products consumed by students at home (students as samplers) were employed as teaching material in three different courses of Genetics during the academic year 2014-2015: Experimental Methods in Food Production (MBTA) (Master level), and Applied Molecular Biology (BMA) and Conservation Genetics and Breeding (COMGE) (Bachelor/Degree level). Molecular genetics based on PCR amplification of DNA markers was employed for species identification of 22 seafood products in COMGE and MBTA, and for detection of genetically modified (GM) maize from nine products in BMA. In total six seafood products incorrectly labeled (27%), and two undeclared GM maize (22%) were found. A post-Laboratory survey was applied for assessing the efficacy of the approach for improving motivation in the Laboratory Practices of Genetics. Results confirmed that students that worked on their own samples from local markets were significantly more motivated and better evaluated their Genetic laboratory practices than control students (χ(2)  = 12.11 p = 0.033). Our results suggest that citizen science approaches could not be only useful for improving teaching of Genetics in universities but also to incorporate students and citizens as active agents in food control. © 2016 by The International Union of Biochemistry and Molecular Biology, 44(5):450-462, 2016. © 2016 The International Union of Biochemistry and Molecular Biology.

Great Cause—Small Effect: Undeclared Genetically Engineered Orange Petunias Harbor an Inefficient Dihydroflavonol 4-Reductase

PubMed Central

Haselmair-Gosch, Christian; Miosic, Silvija; Nitarska, Daria; Roth, Barbara L.; Walliser, Benjamin; Paltram, Renate; Lucaciu, Rares C.; Eidenberger, Lukas; Rattei, Thomas; Olbricht, Klaus; Stich, Karl; Halbwirth, Heidi

2018-01-01

A recall campaign for commercial, orange flowering petunia varieties in spring 2017 caused economic losses worldwide. The orange varieties were identified as undeclared genetically engineered (GE)-plants, harboring a maize dihydroflavonol 4-reductase (DFR, A1), which was used in former scientific transgenic breeding attempts to enable formation of orange pelargonidin derivatives from the precursor dihydrokaempferol (DHK) in petunia. How and when the A1 cDNA entered the commercial breeding process is unclear. We provide an in-depth analysis of three orange petunia varieties, released by breeders from three countries, with respect to their transgenic construct, transcriptomes, anthocyanin composition, and flavonoid metabolism at the level of selected enzymes and genes. The two possible sources of the A1 cDNA in the undeclared GE-petunia can be discriminated by PCR. A special version of the A1 gene, the A1 type 2 allele, is present, which includes, at the 3′-end, an additional 144 bp segment from the non-viral transposable Cin4-1 sequence, which does not add any functional advantage with respect to DFR activity. This unequivocally points at the first scientific GE-petunia from the 1980s as the A1 source, which is further underpinned e.g., by the presence of specific restriction sites, parts of the untranslated sequences, and the same arrangement of the building blocks of the transformation plasmid used. Surprisingly, however, the GE-petunia cannot be distinguished from native red and blue varieties by their ability to convert DHK in common in vitro enzyme assays, as DHK is an inadequate substrate for both the petunia and maize DFR. Recombinant maize DFR underpins the low DHK acceptance, and, thus, the strikingly limited suitability of the A1 protein for a transgenic approach for breeding pelargonidin-based flower color. The effect of single amino acid mutations on the substrate specificity of DFRs is demonstrated. Expression of the A1 gene is generally lower than the petunia DFR expression despite being under the control of the strong, constitutive p35S promoter. We show that a rare constellation in flavonoid metabolism—absence or strongly reduced activity of both flavonol synthase and B-ring hydroxylating enzymes—allows pelargonidin formation in the presence of DFRs with poor DHK acceptance. PMID:29541079

Watershed Watch: Using undergraduate student-driven inquiry-based research projects as a means of engaging undeclared students in the biogeosciences

NASA Astrophysics Data System (ADS)

Rock, B. N.; Hale, S.; Graham, K.; Hayden, L. B.

2009-12-01

Watershed Watch (NSF 0525433) engages early undergraduate students from two-year and four-year colleges in student-driven full inquiry-based instruction in the biogeosciences. Program goals for Watershed Watch are to test if inquiry-rich student-driven projects sufficiently engage undeclared students (or noncommittal STEM majors) to declare a STEM major (or remain with their STEM major). The program is a partnership between two four-year campuses - the University of New Hampshire (UNH), and Elizabeth City State University (ECSU, in North Carolina); and two two-year campuses - Great Bay Community College (GBCC, in New Hampshire) and the College of the Albemarle (COA, in North Carolina). The program focuses on two watersheds: the Merrimack Ricer Watershed in New Hampshire and Massachusetts, and the Pasquotank River Watershed in Virginia and North Carolina. Both the terrestrial and aquatic components of both watersheds are evaluated using the student-driven projects. A significant component of this program is an intensive two-week Summer Research Institute (SRI), in which undeclared freshmen and sophomores investigate various aspects of their local watershed. Two Summer Research Institutes have been held on the UNH campus (2006 and 2008) and two on the ECSU campus (2007 and 2009). Students develop their own research questions and study design, collect and analyze data, and produce a scientific oral or poster presentation on the last day of the SRI. The course objectives, curriculum and schedule are presented as a model for dissemination for other institutions and programs seeking to develop inquiry-rich programs or courses designed to attract students into biogeoscience disciplines. Data from self-reported student feedback indicate the most important factors explaining high-levels of student motivation and research excellence in the program are: 1) working with committed, energetic, and enthusiastic faculty mentors, and 2) faculty mentors demonstrating high degrees of teamwork and coordination. The past four Summer Research Institutes have engaged over 100 entry-level undergraduate students in the process of learning science by doing it, and approximately 50% of those participating have declared majors in a wide range of science fields. A total of eight Watershed Watch students have presented findings from their SRI research projects at AGU meetings in 2007, 2008, and 2009. This presentation will highlight the lessons learned over the past four years in the Watershed Watch program.

Genotype-phenotype correlation and functional studies in patients with cystic fibrosis bearing CFTR complex alleles.

PubMed

Terlizzi, Vito; Castaldo, Giuseppe; Salvatore, Donatello; Lucarelli, Marco; Raia, Valeria; Angioni, Adriano; Carnovale, Vincenzo; Cirilli, Natalia; Casciaro, Rosaria; Colombo, Carla; Di Lullo, Antonella Miriam; Elce, Ausilia; Iacotucci, Paola; Comegna, Marika; Scorza, Manuela; Lucidi, Vincenzina; Perfetti, Anna; Cimino, Roberta; Quattrucci, Serena; Seia, Manuela; Sofia, Valentina Maria; Zarrilli, Federica; Amato, Felice

2017-04-01

The effect of complex alleles in cystic fibrosis (CF) is poorly defined for the lack of functional studies. To describe the genotype-phenotype correlation and the results of either in vitro and ex vivo studies performed on nasal epithelial cells (NEC) in a cohort of patients with CF carrying cystic fibrosis transmembrane conductance regulator ( CFTR ) complex alleles. We studied 70 homozygous, compound heterozygous or heterozygous for CFTR mutations: p.[Arg74Trp;Val201Met;Asp1270Asn], n=8; p.[Ile148Thr;Ile1023_Val1024del], n=5; p.[Arg117Leu;Leu997Phe], n=6; c.[1210-34TG[12];1210-12T[5];2930C>T], n=3; p.[Arg74Trp;Asp1270Asn], n=4; p.Asp1270Asn, n=2; p.Ile148Thr, n=6; p.Leu997Phe, n=36. In 39 patients, we analysed the CFTR gating activity on NEC in comparison with patients with CF (n=8) and carriers (n=4). Finally, we analysed in vitro the p.[Arg74Trp;Val201Met;Asp1270Asn] complex allele. The p.[Ile148Thr;Ile1023_Val1024del] caused severe CF in five compound heterozygous with a class I-II mutation. Their CFTR activity on NEC was comparable with patients with two class I-II mutations (mean 7.3% vs 6.9%). The p.[Arg74Trp;Asp1270Asn] and the p.Asp1270Asn have scarce functional effects, while p.[Arg74Trp;Val201Met;Asp1270Asn] caused mild CF in four of five subjects carrying a class I-II mutation in trans , or CFTR-related disorders (CFTR-RD) in three having in trans a class IV-V mutation. The p.[Arg74Trp;Val201Met;Asp1270Asn] causes significantly (p<0.001) higher CFTR activity compared with compound heterozygous for class I-II mutations. Furthermore, five of six compounds heterozygous with the p.[Arg117Leu;Leu997Phe] had mild CF, whereas the p.Leu997Phe, in trans with a class I-II CFTR mutation, caused CFTR-RD or a healthy status (CFTR activity: 21.3-36.9%). Finally, compounds heterozygous for the c.[1210-34TG[12];1210-12T[5];2930C>T] and a class I-II mutation had mild CF or CFTR-RD (gating activity: 18.5-19.0%). The effect of complex alleles partially depends on the mutation in trans . Although larger studies are necessary, the CFTR activity on NEC is a rapid contributory tool to classify patients with CFTR dysfunction. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.

Plasma amino acids and metabolic profiling of dairy cows in response to a bolus duodenal infusion of leucine

PubMed Central

von Soosten, Dirk; Meyer, Ulrich; Kluess, Jeannette; Dänicke, Sven; Saremi, Behnam; Sauerwein, Helga

2017-01-01

Leucine (Leu), one of the three branch chain amino acids, acts as a signaling molecule in the regulation of overall amino acid (AA) and protein metabolism. Leucine is also considered to be a potent stimulus for the secretion of insulin from pancreatice β-cells. Our objective was to study the effects of a duodenal bolus infusion of Leu on insulin and glucagon secretion, on plasma AA concentrations, and to do a metabolomic profiling of dairy cows as compared to infusions with either glucose or saline. Six duodenum-fistulated Holstein cows were studied in a replicated 3 × 3 Latin square design with 3 periods of 7 days, in which the treatments were applied at the end of each period. The treatments were duodenal bolus infusions of Leu (DIL; 0.15 g/kg body weight), glucose (DIG; at Leu equimolar dosage) or saline (SAL). On the day of infusion, the treatments were duodenally infused after 5 h of fasting. Blood samples were collected at -15, 0, 10, 20, 30, 40, 50, 60, 75, 90, 120, 180, 210, 240 and 300 min relative to the start of infusion. Blood plasma was assayed for concentrations of insulin, glucagon, glucose and AA. The metabolome was also characterized in selected plasma samples (i.e. from 0, 50, and 120 min relative to the infusion). Body weight, feed intake, milk yield and milk composition were recorded throughout the experiment. The Leu infusion resulted in significant increases of Leu in plasma reaching 20 and 15-fold greater values than that in DIG and SAL, respectively. The elevation of plasma Leu concentrations after the infusion led to a significant decrease (P<0.05) in the plasma concentrations of isoleucine, valine, glycine, and alanine. In addition, the mean concentrations of lysine, methionine, phenylalanine, proline, serine, taurine, threonine, and asparagine across all time-points in plasma of DIL cows were reduced (P<0.05) compared with the other groups. In contrast to the working hypothesis about an insulinotropic effect of Leu, the circulating concentrations of insulin were not affected by Leu. In DIG, insulin and glucose concentrations peaked at 30–40 and 40–50 min after the infusion, respectively. Insulin concentrations were greater (P<0.05) from 30–40 min in DIG than DIL and SAL, and glucose was elevated in DIG over DIL and SAL from 30–75 min and 40–50 min, respectively. Multivariate metabolomics data analysis (principal component analysis and partial least squares discriminant analysis) revealed a clear separation when the DIL cows were compared with the DIG and SAL cows at 50 and 120 min after the infusion. By using this analysis, several metabolites, mainly acylcarnitines, methionine sulfoxide and components from the kynurenine pathway were identified as the most relevant for separating the treatment groups. These results suggest that Leu regulates the plasma concentrations of branched-chain AA, and other AA, apparently by stimulating their influx into the cells from the circulation. A single-dose duodenal infusion of Leu did not elicit an apparent insulin response, but affected multiple intermediary metabolic pathways including AA and energy metabolism by mechanisms yet to be elucidated. PMID:28453535

Comparing analgesia and μ-opioid receptor internalization produced by intrathecal enkephalin

PubMed Central

Chen, Wenling; Song, Bingbing; Lao, Lijun; Pérez, Orlando A.; Kim, Woojae; Marvizón, Juan Carlos G.

2007-01-01

Summary Opioid receptors in the spinal cord produce strong analgesia, but the mechanisms controlling their activation by endogenous opioids remain unclear. We have previously shown in spinal cord slices that peptidases preclude μ-opioid receptor (MOR) internalization by opioids. Our present goals were to investigate whether enkephalin-induced analgesia is also precluded by peptidases, and whether it is mediated by MORs or δ-opioid receptors (DORs). Tail-flick analgesia and MOR internalization were measured in rats injected intrathecally with Leu-enkephalin and peptidase inhibitors. Without peptidase inhibitors, Leu-enkephalin produced neither analgesia nor MOR internalization at doses up to 100 nmol, whereas with peptidase inhibitors it produced analgesia at 0.3 nmol and MOR internalization at 1 nmol. Leu-enkephalin was ten times more potent to produce analgesia than to produce MOR internalization, suggesting that DORs were involved. Selective MOR or DOR antagonists completely blocked the analgesia elicited by 0.3 nmol Leu-enkephalin (a dose that produced little MOR internalization), indicating that it involved these two receptors, possibly by an additive or synergistic interaction. The selective MOR agonist endomorphin-2 produced analgesia even in the presence of a DOR antagonist, but at doses substantially higher than Leu-enkephalin. Unlike Leu-enkephalin, endomorphin-2 had the same potencies to induce analgesia and MOR internalization. We concluded that low doses of enkephalins produce analgesia by activating both MORs and DORs. Analgesia can also be produced exclusively by MORs at higher agonist doses. Since peptidases prevent the activation of spinal opioid receptors by enkephalins, the coincident release of opioids and endogenous peptidase inhibitors may be required for analgesia. PMID:17845806

Comparison of L-selectin blood level and gene polymorphism in tuberculosis patients with healthy individuals.

PubMed

Eini, Peyman; Shirvani, Maria; Hajilooi, Mehrdad; Esna-Ashari, Farzaneh

2018-02-12

The inflammatory response to Mycobacterium tuberculosis bacilli influences tuberculosis (TB) progression. In this study, we aimed to identify the Phe206Leu polymorphism and serum L-selectin level in TB patients, compared to healthy individuals. Ninety patients with a diagnosis of TB and 90 healthy controls were selected in this study. The serum L-selectin level was determined, using ELISA. L-selectin polymorphism was also evaluated using PCR. For data analysis, SPSS was used at a significance level of 0.05. According to the findings, the mean±SD age of the participants was 57.5 ± 18.4 and 56.5 ± 17.5 years in the TB and healthy groups, respectively. The TB group showed a significantly higher serum L-selectin level (1721.1 ± 330.9) versus the healthy controls (1624 ± 279). The L-selectin Phe allele frequencies were higher than the Leu allele frequencies in the main population, whereas the patients and controls were not significantly different. Eight (0.04%) subjects had Leu/Leu genotypes, 84 (46.6%) carried Phe/Leu genotypes, and 88 (48.8%) had Phe/Phe genotypes. Our results showed that the groups were not significantly different regarding L-selectin genotypes. TB patients had a significantly higher serum L-selectin level, compared to the controls. Based on the findings, the incidence of TB and L-selectin polymorphism in the Phe206Leu gene had no significant association. © 2018 Wiley Periodicals, Inc.

Hypogonadotropic hypogonadism due to a novel missense mutation in the first extracellular loop of the neurokinin B receptor.

PubMed

Guran, Tulay; Tolhurst, Gwen; Bereket, Abdullah; Rocha, Nuno; Porter, Keith; Turan, Serap; Gribble, Fiona M; Kotan, L Damla; Akcay, Teoman; Atay, Zeynep; Canan, Husniye; Serin, Ayse; O'Rahilly, Stephen; Reimann, Frank; Semple, Robert K; Topaloglu, A Kemal

2009-10-01

The neurokinin B (NKB) receptor, encoded by TACR3, is widely expressed within the central nervous system, including hypothalamic nuclei involved in regulating GnRH release. We have recently reported two mutations in transmembrane segments of the receptor and a missense mutation in NKB in patients with normosmic isolated hypogonadotropic hypogonadism (nIHH). We sequenced the TACR3 gene in a family in which three siblings had nIHH. The novel mutant receptor thus identified was studied in a heterologous expression system using calcium flux as the functional readout. All affected siblings were homozygous for the His148Leu mutation, in the first extracellular loop of the NKB receptor. The His148Leu mutant receptor exhibited profoundly impaired signaling in response to NKB (EC(50) = 3 +/- 0.1 nm and >5 microm for wild-type and His148Leu, respectively). The location of the mutation in an extracellular part of the receptor led us also to test whether senktide, a synthetic NKB analog, may retain ability to stimulate the mutant receptor. However, the signaling activity of the His148Leu receptor in response to senktide was also severely impaired (EC(50) = 1 +/- 1 nm for wild-type and no significant response of His148Leu to 10 microm). Homozygosity for the TACR3 His148Leu mutation leads to failure of sexual maturation in humans, whereas signaling by the mutant receptor in vitro in response to either NKB or senktide is severely impaired. These observations further strengthen the link between NKB, the NKB receptor, and regulation of human reproductive function.

Toxicity of irradiated advanced heavy water reactor fuels.

PubMed

Priest, N D; Richardson, R B; Edwards, G W R

2013-02-01

The good neutron economy and online refueling capability of the CANDU® heavy water moderated reactor (HWR) enable it to use many different fuels such as low enriched uranium (LEU), plutonium, or thorium, in addition to its traditional natural uranium (NU) fuel. The toxicity and radiological protection methods for these proposed fuels, unlike those for NU, are not well established. This study uses software to compare the fuel composition and toxicity of irradiated NU fuel against those of two irradiated advanced HWR fuel bundles as a function of post-irradiation time. The first bundle investigated is a CANFLEX® low void reactor fuel (LVRF), of which only the dysprosium-poisoned central element, and not the outer 42 LEU elements, is specifically analyzed. The second bundle investigated is a heterogeneous high-burnup (LEU,Th)O(2) fuelled bundle, whose two components (LEU in the outer 35 elements and thorium in the central eight elements) are analyzed separately. The LVRF central element was estimated to have a much lower toxicity than that of NU at all times after shutdown. Both the high burnup LEU and the thorium fuel had similar toxicity to NU at shutdown, but due to the creation of such inhalation hazards as (238)Pu, (240)Pu, (242)Am, (242)Cm, and (244)Cm (in high burnup LEU), and (232)U and (228)Th (in irradiated thorium), the toxicity of these fuels was almost double that of irradiated NU after 2,700 d of cooling. New urine bioassay methods for higher actinoids and the analysis of thorium in fecal samples are recommended to assess the internal dose from these two fuels.

Experiments of the origins of optical activity.

PubMed

Bonner, W A; Flores, J J

1975-01-01

Two recent reports claim that (1) aqueous L-aspartic acid polymerizes faster than D-Asp in the presence of kaolin at 90 degrees, and (2) L-phenylalanine is adsorbed by kaolin more extensively than D-Phe at pH 4(the reverse being true at pH2). The novelty of these observations and their potential significance for the origin of optical activity has prompted us to duplicate these experiments using more sensitive methods. L- and D, L-Asp in 0.01 M solution were incubated with kaolin at 90 degrees for 8 days. Careful examination of the aqueous residues from such experiments failed to demonstrate any preferential polymerization of L-Asp over D-Asp, or indeed any significant gross polymerization of Asp at all. In other experiments 0.001 M solutions of D, L-Phe at pH 6 and pH 2 were stirred with large excesses of kaolin for 24 hr, and the aqueous extracts from these mixtures were examined for gross adsorption using the amino acid analyzer. No significant gross adsorption was noted. We then looked for asymmetric adsorption in the aqueous residues using optical rotatory dispersion, gas chromatography and thin layer chromatography. By none of these analytical criteria could we find any evidence whatsoever for the preferential adsorption of D- versus L-Phe from either pH 6 or pH 2 solutions. Finally, in experiments bearing on the origin of optical activity by parity violation during beta-decay, we have irradiated solid samples of D-, L- and D,L-leucine in a 61700 Ci Sr-90 source at Oak Ridge National Lab. for 1.34 yr (total dose: 4.2 x 10(8) rad). Gas chromatographic examination of the (appropriately derivitized) recovered samples showed that the L-Leu was 16.7% decomposed, the D-Leu 11.4% and theD,L-Leu 13.8% decomposed. The recovered D,L-Leu sample had a gas-chromatographically determined enantiomeric composition of 50.8% D-leu and 49.2% L-Leu. These data, though very close to experimental error, may indicate a slight preferential radiolysis of L-Leu compared to D-Leu by the Bremsstrahlung from Sr-90 beta-decay. These high intensity irradiation experiments are being continued on a prolonged basis in order to reach more definitive conclusions.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hooper, R.

Since the end of the Cold War the world has witnessed a remarkable series of events demonstrating that universal adherence to the principles of nuclear non-proliferation and disarmament are no longer utopian dreams. The author reviews the actions of various countries to terminate or reduce nuclear weapons programs and those that are resisting the non-proliferation efforts. The author addresses efforts of the International Atomic Energy Agency (IAEA) to safeguard declared nuclear material more cost-effectively and deal with the possibility of undeclared nuclear activities.

Nuclear Proliferation: Lessons Learned from the Iraqi Case

DTIC Science & Technology

1992-12-01

RECONNAISSANCE ... ........ 85 B. POLITICAL WEAPONS ........... ............... 94 C. EXPORT CONTROLS AND ECONOMIC TOOLS ...... 105 CONCLUSION...contain a clause that allows the I.A.E.A. to inspect undeclared facilities, but the I.A.E.A. has "virtually" never had the political will to invoke it...provisions, since the agency has no method of enforcement on its own. The issue of " political will" is one that must be discussed in more detail, since the

Exploratory field trial of motorcycle autonomous emergency braking (MAEB): Considerations on the acceptability of unexpected automatic decelerations.

PubMed

Savino, Giovanni; Pierini, Marco; Thompson, Jason; Fitzharris, Michael; Lenné, Michael G

2016-11-16

Autonomous emergency braking (AEB) acts to slow down a vehicle when an unavoidable impending collision is detected. In addition to documented benefits when applied to passenger cars, AEB has also shown potential when applied to motorcycles (MAEB). However, the feasibility of MAEB as practically applied to motorcycles in the real world is not well understood. In this study we performed a field trial involving 16 riders on a test motorcycle subjected to automatic decelerations, thus simulating MAEB activation. The tests were conducted along a rectilinear path at nominal speed of 40 km/h and with mean deceleration of 0.15 g (15% of full braking) deployed at random times. Riders were also exposed to one final undeclared brake activation with the aim of providing genuinely unexpected automatic braking events. Participants were consistently able to manage automatic decelerations of the vehicle with minor to moderate effort. Results of undeclared activations were consistent with those of standard runs. This study demonstrated the feasibility of a moderate automatic deceleration in a scenario of motorcycle travelling in a straight path, supporting the notion that the application of AEB on motorcycles is practicable. Furthermore, the proposed field trial can be used as a reference for future regulation or consumer tests in order to address safety and acceptability of unexpected automatic decelerations on a motorcycle.

Development of a novel dry powder inhalation formulation for the delivery of rivastigmine hydrogen tartrate.

PubMed

Simon, Alice; Amaro, Maria Inês; Cabral, Lucio Mendes; Healy, Anne Marie; de Sousa, Valeria Pereira

2016-03-30

The purpose of this study was to prepare engineered particles of rivastigmine hydrogen tartrate (RHT) and to characterize the physicochemical and aerodynamic properties, in comparison to a lactose carrier formulation (LCF). Microparticles were prepared from ethanol/water solutions containing RHT with and without the incorporation of L-leucine (Leu), using a spray dryer. Dry powder inhaler formulations prepared were characterized by scanning electron microscopy, powder X-ray diffraction, laser diffraction particle sizing, ATR-FTIR, differential scanning calorimetry, bulk and tapped density, dynamic vapour sorption and in vitro aerosol deposition behaviour using a next generation impactor. The smooth-surfaced spherical morphology of the spray dried microparticles was altered by adding Leu, resulting in particles becoming increasingly wrinkled with increasing Leu. Powders presented low densities. The glass transition temperature was sufficiently high (>90 °C) to suggest good stability at room temperature. As Leu content increased, spray dried powders presented lower residual solvent content, lower particle size, higher fine particle fraction (FPF<5 μm), and lower mass median aerodynamic diameter (MMAD). The LCF showed a lower FPF and higher MMAD, relative to the spray dried formulations containing more than 10% Leu. Spray dried RHT powders presented better aerodynamic properties, constituting a potential drug delivery system for oral inhalation. Copyright © 2016. Published by Elsevier B.V.

Purification and in vitro antioxidative effects of giant squid muscle peptides on free radical-mediated oxidative systems.

PubMed

Rajapakse, Niranjan; Mendis, Eresha; Byun, Hee-Guk; Kim, Se-Kwon

2005-09-01

Low molecular weight peptides obtained from ultrafiltration (UF) of giant squid (Dosidicus gigas) muscle protein were studied for their antioxidative effects in different in vitro oxidative systems. The most potent two peptides, Asn-Ala-Asp-Phe-Gly-Leu-Asn-Gly-Leu-Glu-Gly-Leu-Ala (1307 Da) and Asn-Gly-Leu-Glu-Gly-Leu-Lys (747 Da), exhibited their antioxidant potential to act as chain-breaking antioxidants by inhibiting radical-mediated peroxidation of linoleic acid, and their activities were closer to highly active synthetic antioxidant, butylated hydroxytoluene. Addition of these peptides could enhance the viability of cytotoxic embryonic lung fibroblasts significantly (P<.05) at a low concentration of 50 microg/ml, and it was presumed due to the suppression of radical-induced oxidation of membrane lipids. Electron spin trapping studies revealed that the peptides were potent scavengers of free radicals in the order of carbon-centered (IC(50) 396.04 and 304.67 microM), hydroxyl (IC(50) 497.32 and 428.54 microM) and superoxide radicals (IC(50) 669.34 and 573.83 microM). Even though the exact molecular mechanism for scavenging of free radicals was unclear, unusually high hydrophobic amino acid composition (more than 75%) of giant squid muscle peptides was presumed to be involved in the observed activities.

Identification of a Second Substrate-binding Site in Solute-Sodium Symporters*

PubMed Central

Li, Zheng; Lee, Ashley S. E.; Bracher, Susanne; Jung, Heinrich; Paz, Aviv; Kumar, Jay P.; Abramson, Jeff; Quick, Matthias; Shi, Lei

2015-01-01

The structure of the sodium/galactose transporter (vSGLT), a solute-sodium symporter (SSS) from Vibrio parahaemolyticus, shares a common structural fold with LeuT of the neurotransmitter-sodium symporter family. Structural alignments between LeuT and vSGLT reveal that the crystallographically identified galactose-binding site in vSGLT is located in a more extracellular location relative to the central substrate-binding site (S1) in LeuT. Our computational analyses suggest the existence of an additional galactose-binding site in vSGLT that aligns to the S1 site of LeuT. Radiolabeled galactose saturation binding experiments indicate that, like LeuT, vSGLT can simultaneously bind two substrate molecules under equilibrium conditions. Mutating key residues in the individual substrate-binding sites reduced the molar substrate-to-protein binding stoichiometry to ∼1. In addition, the related and more experimentally tractable SSS member PutP (the Na+/proline transporter) also exhibits a binding stoichiometry of 2. Targeting residues in the proposed sites with mutations results in the reduction of the binding stoichiometry and is accompanied by severely impaired translocation of proline. Our data suggest that substrate transport by SSS members requires both substrate-binding sites, thereby implying that SSSs and neurotransmitter-sodium symporters share common mechanistic elements in substrate transport. PMID:25398883

Molecular screening of the ghrelin gene in Italian obese children: the Leu72Met variant is associated with an earlier onset of obesity.

PubMed

Miraglia del Giudice, E; Santoro, N; Cirillo, G; Raimondo, P; Grandone, A; D'Aniello, A; Di Nardo, M; Perrone, L

2004-03-01

To test whether ghrelin variants could play a role in modulating some aspects of the obese phenotype during childhood. We screened the ghrelin gene in 300 Italian obese children and adolescents (mean age 10.5+/-3.2 y; range 4-19 y) and 200 controls by using the single-strand conformation polymorphism and the restriction fragment length polymoprhism analysis. No mutations were detected with the exception of two previously described polymorphisms, Arg51Gln and Leu72Met. For both variations, allelic frequencies were similar between patients and controls. Interestingly, we showed that the Leu72Met polymorphism was associated with differences in the age at obesity onset. Patients with the Met72 allele became obese earlier than homozygous patients for the wild Leu72 allele. The logrank test comparing the plots of the complement of Kaplan-Meier estimates between the two groups of patients was statistically significant (P<0.0001). It is unlikely that ghrelin variations cause the obesity due to single-gene mutations. The Leu72Met polymorphism of the ghrelin gene seems to play a role in anticipating the onset of obesity among children suggesting, therefore, that ghrelin may be involved in the pathophysiology of human adiposity.

Comparative sequence analysis of a region on human chromosome 13q14, frequently deleted in B-cell chronic lymphocytic leukemia, and its homologous region on mouse chromosome 14.

PubMed

Kapanadze, B; Makeeva, N; Corcoran, M; Jareborg, N; Hammarsund, M; Baranova, A; Zabarovsky, E; Vorontsova, O; Merup, M; Gahrton, G; Jansson, M; Yankovsky, N; Einhorn, S; Oscier, D; Grandér, D; Sangfelt, O

2000-12-15

Previous studies have indicated the presence of a putative tumor suppressor gene on human chromosome 13q14, commonly deleted in patients with B-cell chronic lymphocytic leukemia (B-CLL). We have recently identified a minimally deleted region encompassing parts of two adjacent genes, termed LEU1 and LEU2 (leukemia-associated genes 1 and 2), and several additional transcripts. In addition, 50 kb centromeric to this region we have identified another gene, LEU5/RFP2. To elucidate further the complex genomic organization of this region, we have identified, mapped, and sequenced the homologous region in the mouse. Fluorescence in situ hybridization analysis demonstrated that the region maps to mouse chromosome 14. The overall organization and gene order in this region were found to be highly conserved in the mouse. Sequence comparison between the human deletion hotspot region and its homologous mouse region revealed a high degree of sequence conservation with an overall score of 74%. However, our data also show that in terms of transcribed sequences, only two of those, human LEU2 and LEU5/RFP2, are clearly conserved, strengthening the case for these genes as putative candidate B-CLL tumor suppressor genes.

Direct Down-scale Experiments of Concentration Column Designs for SHINE Process

DOE Office of Scientific and Technical Information (OSTI.GOV)

Youker, Amanda J.; Stepinski, Dominique C.; Vandegrift, George F.

Argonne is assisting SHINE Medical Technologies in their efforts to become a domestic Mo-99 producer. The SHINE accelerator-driven process uses a uranyl-sulfate target solution for the production of fission-product Mo-99. Argonne has developed a molybdenum recovery and purification process for this target solution. The process includes an initial Mo recovery column followed by a concentration column to reduce the product volume from 15-25 L to < 1 L prior to entry into the LEU Modified Cintichem (LMC) process for purification.1 This report discusses direct down-scale experiments of the plant-scale concentration column design, where the effects of loading velocity and temperaturemore » were investigated.« less

Dry powder inhalers of gentamicin and leucine: formulation parameters, aerosol performance and in vitro toxicity on CuFi1 cells.

PubMed

Aquino, R P; Prota, L; Auriemma, G; Santoro, A; Mencherini, T; Colombo, G; Russo, P

2012-04-15

The high hygroscopicity of gentamicin (G) as raw material hampers the production of respirable particles during aerosol generation and prevents its direct use as powder for inhalation in patients suffering from cystic fibrosis (CF). Therefore, this research aimed to design a new dry powder formulation of G studying dispersibility properties of an aminoacid, L-leucine (leu), and appropriate process conditions. Spray-dried powders were characterized as to water uptake, particle size distribution, morphology and stability, in correlation with process parameters. Aerodynamic properties were analyzed both by Single Stage Glass Impinger and Andersen Cascade Impactor. Moreover, the potential cytotoxicity on bronchial epithelial cells bearing a CFTR F508/F508 mutant genotype (CuFi1) were tested. Results indicated that leu may improve the aerosol performance of G-dried powders. The maximum fine particle fraction (FPF) of about 58.3% was obtained when water/isopropyl alcohol 7:3 system and 15-20% (w/w) of leu were used, compared to a FPF value of 13.4% for neat G-dried powders. The enhancement of aerosol efficiency was credited both to the improvement of the powder flowability, caused by the dispersibility enhancer (aminoacid), and to the modification of the particle surface due to the influence of the organic co-solvent on drying process. No significant degradation of the dry powder was observed up to 6 months of storage. Moreover, particle engineering did not affect either the cell viability or cell proliferation of CuFi1 over a 24 h period. Copyright © 2012 Elsevier B.V. All rights reserved.

Hydrolysis of substance P in the presence of the osteosarcoma cell line SaOS-2: release of free amino acids.

PubMed

Cavazza, Antonella; Marini, Mario; Roda, L Giorgio; Tarantino, Umberto; Valenti, Angela

2011-12-01

The possible hydrolysis of substance P (Arg-Pro-Lys-Pro-Gln-Gln-Phe-Phe-Gly-Leu-Met) in presence of the osteoblastic cell line SaOS-2 was measured by capillary electrophoresis coupled to mass detection. The results obtained indicate that a very rapid disappearance of the intact undecapeptide was associated to a slower appearance of seven of its eight component amino acids. These results can be interpreted as indicating that an extremely fast hydrolysis of substance P by endopeptidases, which released peptidic by-products, was followed by a noticeably slower secondary degradation which released free amino acids. In decreasing quantitative importance, these phenomena appear to originate by the hydrolysis of the Pro(4)-Gln(5) bond, followed by C-terminal sequential degradation of the Arg(1)-Pro(4) tetrapeptide; by the hydrolysis of or Phe(7)-Phe(8) bond (or, possibly, of Gln(6)-Phe(7)) leading to release of free Phe and Gln; by hydrolysis of the Gly(9)-Leu(10) bond with subsequent release of Met and Leu. Results obtained appear to be compatible with the expression by SaOS-2 cells of enzymes already known to catalyze substance P hydrolysis, together with an apparent low efficiency of aminopeptidases. Because of the activity of C-terminal fragments on NK1 receptors, the delay between primary hydrolysis of substance P and secondary hydrolysis of its peptidic fragments indicated by the data shown implies a possible persistence of substance P physiological effects even after degradation of the intact peptide.

Supplemental Thermal-Hydraulic Transient Analyses of BR2 in Support of Conversion to LEU Fuel

DOE Office of Scientific and Technical Information (OSTI.GOV)

Licht, J.; Dionne, B.; Sikik, E.

2016-01-01

Belgian Reactor 2 (BR2) is a research and test reactor located in Mol, Belgium and is primarily used for radioisotope production and materials testing. The Materials Management and Minimization (M3) Reactor Conversion Program of the National Nuclear Security Administration (NNSA) is supporting the conversion of the BR2 reactor from Highly Enriched Uranium (HEU) fuel to Low Enriched Uranium (LEU) fuel. The RELAP5/Mod 3.3 code has been used to perform transient thermal-hydraulic safety analyses of the BR2 reactor to support reactor conversion. A RELAP5 model of BR2 has been validated against select transient BR2 reactor experiments performed in 1963 by showingmore » agreement with measured cladding temperatures. Following the validation, the RELAP5 model was then updated to represent the current use of the reactor; taking into account core configuration, neutronic parameters, trip settings, component changes, etc. Simulations of the 1963 experiments were repeated with this updated model to re-evaluate the boiling risks associated with the currently allowed maximum heat flux limit of 470 W/cm 2 and temporary heat flux limit of 600 W/cm 2. This document provides analysis of additional transient simulations that are required as part of a modern BR2 safety analysis report (SAR). The additional simulations included in this report are effect of pool temperature, reduced steady-state flow rate, in-pool loss of coolant accidents, and loss of external cooling. The simulations described in this document have been performed for both an HEU- and LEU-fueled core.« less

Synthesis of poly(alkenoic acid) with L-leucine residue and methacrylate photopolymerizable groups useful in formulating dental restorative materials.

PubMed

Buruiana, Tinca; Nechifor, Marioara; Melinte, Violeta; Podasca, Viorica; Buruiana, Emil C

2014-01-01

To develop resin-modified glass ionomer materials, we synthesized methacrylate-functionalized acrylic copolymer (PAlk-LeuM) derived from acrylic acid, itaconic acid and N-acryloyl-L-leucine using (N-methacryloyloxyethylcarbamoyl-N'-4-hydroxybutyl) urea as the modifying agent. The spectroscopic (proton/carbon nuclear magnetic resonance, Fourier transform infrared spectroscopy) characteristics, and the gel permeation chromatography/Brookfield viscosity measurements were analysed and compared with those of the non-modified copolymer (PAlk-Leu). The photocurable copolymer (PAlk-LeuM, ~14 mol% methacrylate groups) and its precursor (PAlk-Leu) were incorporated in dental ionomer compositions besides diglycidyl methacrylate of bisphenol A (Bis-GMA) or an analogue of Bis-GMA (Bis-GMA-1), triethylene glycol dimethacrylate and 2-hydroxyethyl methacrylate. The kinetic data obtained by photo-differential scanning calorimetry showed that both the degree of conversion (60.50-75.62%) and the polymerization rate (0.07-0.14 s(-1)) depend mainly on the amount of copolymer (40-50 wt.%), and conversions over 70% were attained in the formulations with 40 wt.% PAlk-LeuM. To formulate light-curable cements, each organic composition was mixed with filler (90 wt.% fluoroaluminosilicate/10 wt.% hydroxyapatite) into a 2.7:1 ratio (powder/liquid ratio). The light-cured specimens exhibited flexural strength (FS), compressive strength (CS) and diametral tensile strength (DTS) varying between 28.08 and 64.79 MPa (FS), 103.68-147.13 MPa (CS) and 16.89-31.87 MPa (DTS). The best values for FS, CS and DTS were found for the materials with the lowest amount of PAlk-LeuM. Other properties such as the surface hardness, water sorption/water solubility, surface morphology and fluorescence caused by adding the fluorescein monomer were also evaluated.

Analysis of the TREAT LEU Conceptual Design

DOE Office of Scientific and Technical Information (OSTI.GOV)

Connaway, H. M.; Kontogeorgakos, D. C.; Papadias, D. D.

2016-03-01

Analyses were performed to evaluate the performance of the low enriched uranium (LEU) conceptual design fuel for the conversion of the Transient Reactor Test Facility (TREAT) from its current highly enriched uranium (HEU) fuel. TREAT is an experimental nuclear reactor designed to produce high neutron flux transients for the testing of reactor fuels and other materials. TREAT is currently in non-operational standby, but is being restarted under the U.S. Department of Energy’s Resumption of Transient Testing Program. The conversion of TREAT is being pursued in keeping with the mission of the Department of Energy National Nuclear Security Administration’s Material Managementmore » and Minimization (M3) Reactor Conversion Program. The focus of this study was to demonstrate that the converted LEU core is capable of maintaining the performance of the existing HEU core, while continuing to operate safely. Neutronic and thermal hydraulic simulations have been performed to evaluate the performance of the LEU conceptual-design core under both steady-state and transient conditions, for both normal operation and reactivity insertion accident scenarios. In addition, ancillary safety analyses which were performed for previous LEU design concepts have been reviewed and updated as-needed, in order to evaluate if the converted LEU core will function safely with all existing facility systems. Simulations were also performed to evaluate the detailed behavior of the UO 2-graphite fuel, to support future fuel manufacturing decisions regarding particle size specifications. The results of these analyses will be used in conjunction with work being performed at Idaho National Laboratory and Los Alamos National Laboratory, in order to develop the Conceptual Design Report project deliverable.« less

l-Leucine acts as a potential agent in reducing body temperature at hatching and affords thermotolerance in broiler chicks.

PubMed

Han, Guofeng; Yang, Hui; Bahry, Mohammad A; Tran, Phuong V; Do, Phong H; Ikeda, Hiromi; Furuse, Mitsuhiro; Chowdhury, Vishwajit S

2017-02-01

Thermal manipulation (TM) of incubation temperature causes metabolic alterations and contributes to improving thermotolerance in chicks post hatching. However, there has been no report on amino acid metabolism during TM and the part it plays in thermotolerance. In this study, we therefore first analyzed free amino acid concentrations in the embryonic brain and liver during TM (38.6°C, 6h/d during embryonic day (ED) 10 to ED 18). It was found that leucine (Leu), phenylalanine and lysine were significantly decreased in the embryonic brain and liver. We then chose l-Leu and other branched-chain amino acids (l-isoleucine (L-Ile) and l-valine (l-Val)) for in ovo injection on ED 7 to reveal their roles in thermoregulation, growth, food intake and thermotolerance in chicks. It was found that in ovo injection of l-Leu, but not of l-Ileu or l-Val, caused a significant decline in body temperature at hatching and increased food intake and body weight gain in broiler chicks. Interestingly, in ovo injection of l-Leu resulted in the acquisition of thermotolerance under high ambient temperature (35±1°C for 180min) in comparison with the control thermoneutral temperature (28±1°C for 180min). These results indicate that the free amino acid concentrations during embryogenesis were altered by TM. l-Leu administration in eggs caused a reduction in body temperature at hatching, and afforded thermotolerance in heat-exposed young chicks, further suggesting that l-Leu may be one of the key metabolic factors involved in controlling body temperature in embryos, as well as in producing thermotolerance after hatching. Copyright © 2016 Elsevier Inc. All rights reserved.

High frequency of Neuropeptide Y Leu7Pro polymorphism in an Iranian population and its association with coronary artery disease.

PubMed

Masoudi-Kazemabad, Ali; Jamialahmadi, Khadijeh; Moohebati, Mohsen; Mojarrad, Majid; Dehghan-Manshadi, Raheleh; Forghanifard, Mohammad Mahdi; Akhlaghi, Saeed; Ferns, Gordon A; Ghayour-Mobarhan, Majid

2012-03-15

Neuropeptide Y (NPY), a 36-amino acid peptide, is widely expressed in the central and peripheral nervous systems as well as in the heart. A relationship has been reported between NPY gene variants and coronary artery disease (CAD) in some populations. However, there are few data on the NPY gene polymorphism and CAD in the Persian population. In the current study we have investigated the relationship between the NPY Leu7Pro polymorphism and CAD within a population from Iran. A total of 1061 subjects were recruited; 609 patients and 452 healthy subjects. Four hundred and twenty eight of the patients had >50% stenosis; with the remaining 181 patients having <50% stenosis based on angiography. Angiography positive patients were divided into three groups: those with single (n=115), double (n=140), and triple vessel (n=173) disease. DNA analysis for the Leu7Pro polymorphism was performed using a PCR-RFLP technique. A significantly higher frequency of the Leu7Pro genotype was observed in CAD patients compared with the control group (P<0.05). Patients with the Pro7 had significantly higher values for weight (P=0.027), BMI (P=0.001), hip circumference (P=0.003) and prevalence of diabetes mellitus (P=0.018) but reduced prevalence of a history of myocardial infarction (P=0.017). The frequency of Leu7Pro polymorphism of NPY was 5.9% in our Iranian population; higher than reported for other Asian populations. The Leu7Pro polymorphism was associated with CAD in an Iranian population. Copyright © 2012 Elsevier B.V. All rights reserved.

Guinea Pig Chymase Is Leucine-specific

PubMed Central

Caughey, George H.; Beauchamp, Jeremy; Schlatter, Daniel; Raymond, Wilfred W.; Trivedi, Neil N.; Banner, David; Mauser, Harald; Fingerle, Jürgen

2008-01-01

To explore guinea pigs as models of chymase biology, we cloned and expressed the guinea pig ortholog of human chymase. In contrast to rats and mice, guinea pigs appear to express just one chymase, which belongs to the α clade, like primate chymases and mouse mast cell protease-5. The guinea pig enzyme autolyzes at Leu residues in the loop where human chymase autolyzes at Phe. In addition, guinea pig α-chymase selects P1 Leu in a combinatorial peptide library and cleaves Ala-Ala-Pro-Leu-4-nitroanilide but has negligible activity toward substrates with P1 Phe and does not cleave angiotensin I. This contrasts with human chymase, which cleaves after Phe or Tyr, prefers P1 Phe in peptidyl 4-nitroanilides, and avidly hydrolyzes angiotensin I at Phe8 to generate bioactive angiotensin II. The guinea pig enzyme also is inactivated more effectively by α1-antichymotrypsin, which features P1 Leu in the reactive loop. Unlike mouse, rat, and hamster α-chymases, guinea pig chymase lacks elastase-like preference for P1 Val or Ala. Partially humanized A216G guinea pig chymase acquires human-like P1 Phe- and angiotensin-cleaving capacity. Molecular models suggest that the wild type active site is crowded by the Ala216 side chain, which potentially blocks access by bulky P1 aromatic residues. On the other hand, the guinea pig pocket is deeper than in Val-selective chymases, explaining the preference for the longer aliphatic side chain of Leu. These findings are evidence that chymase-like peptidase specificity is sensitive to small changes in structure and provide the first example of a vertebrate Leu-selective peptidase. PMID:18353771

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fryburg, D.A.; Barrett, E.J.; Louard, R.J.

To assess the effect of fasting on muscle protein turnover in the basal state and in response to insulin, we measured forearm amino acid kinetics, using (3H)phenylalanine (Phe) and (14C)leucine (Leu) infused systemically, in eight healthy subjects after 12 (postabsorptive) and 60 h of fasting. After a 150-min basal period, forearm local insulin concentration was selectively raised by approximately 25 muU/ml for 150 min by intra-arterial insulin infusion (0.02 mU.kg-1. min-1). The 60-h fast increased urine nitrogen loss and whole body Leu flux and oxidation (by 50-75%, all P less than 0.02). Post-absorptively, forearm muscle exhibited a net release ofmore » Phe and Leu, which increased two- to threefold after the 60-h fast (P less than 0.05); this effect was mediated exclusively by accelerated local rates of amino acid appearance (Ra), with no reduction in rates of disposal (Rd). Local hyperinsulinemia in the postabsorptive condition caused a twofold increase in forearm glucose uptake (P less than 0.01) and completely suppressed the net forearm output of Phe and Leu (P less than 0.02). After the 60-h fast, forearm glucose disposal was depressed basally and showed no response to insulin; in contrast, insulin totally abolished the accelerated net forearm release of Phe and Leu. The action of insulin to reverse the augmented net release of Phe and Leu was mediated exclusively by approximately 40% suppression of Ra (P less than 0.02) rather than a stimulation of Rd. We conclude that in short-term fasted humans (1) muscle amino acid output accelerates due to increased proteolysis rather than reduced protein synthesis, and (2) despite its catabolic state and a marked impairment in insulin-mediated glucose disposal, muscle remains sensitive to insulin's antiproteolytic action.« less

Norbornene-constrained cyclic peptides with hairpin architecture: design, synthesis, conformation, and membrane ion transport.

PubMed

Ranganathan, D; Haridas, V; Kurur, S; Nagaraj, R; Bikshapathy, E; Kunwar, A C; Sarma, A V; Vairamani, M

2000-01-28

A novel family of hairpin cyclic peptides has been designed on the basis of the use of norbornene units as the bridging ligands. The design is flexible with respect to the choice of an amino acid, the ring size, and the nature of the second bridging ligand as illustrated here with the preparation of a large number of norborneno cyclic peptides containing a variety of amino acids in ring sizes varying from 12- to 29-membered, with the choice of the second bridging ligand being a rigid norbornene (11, 13a,b), an adamantane unit (7a,b and 8), or a flexible cystine residue (4a,b and 10). The presence of built-in handles (as protected COOH groups) permits the attachment of a variety of subunits as shown here with the ligation of Leu-Leu, Val-Val, or Aib-Aib pendants in 4b, 7b, and 13b, respectively. This novel class of constrained cyclic peptides are demonstrated to adopt beta-sheet- or hairpin-like conformation as shown by (1)H NMR and CD spectra. Membrane ion-transport studies have shown that the norborneno cyclic peptides 4b and 7b containing Leu-Leu or Val-Val pendants symmetrically placed on the exterior of the ring show high efficiency and selectivity in the transport of specifically monovalent cations. This property can be attributed to the hairpin-like architecture induced by the norbornene unit since the bis-adamantano peptide 15 containing two pairs of Leu-Leu pendants on the exterior is able to transport both monovalent (Na(+), K(+)) and divalent (Mg(2+)/Ca(2+)) cations.

Purification and characterization of a surfactin-like molecule produced by Bacillus sp. H2O-1 and its antagonistic effect against sulfate reducing bacteria.

PubMed

Korenblum, Elisa; de Araujo, Livia Vieira; Guimarães, Carolina Reis; de Souza, Lauro M; Sassaki, Guilherme; Abreu, Fernanda; Nitschke, Márcia; Lins, Ulysses; Freire, Denise Maria Guimarães; Barreto-Bergter, Eliana; Seldin, Lucy

2012-11-07

Bacillus sp. H2O-1, isolated from the connate water of a Brazilian reservoir, produces an antimicrobial substance (denoted as AMS H2O-1) that is active against sulfate reducing bacteria, which are the major bacterial group responsible for biogenic souring and biocorrosion in petroleum reservoirs. Thus, the use of AMS H2O-1 for sulfate reducing bacteria control in the petroleum industry is a promising alternative to chemical biocides. However, prior to the large-scale production of AMS H2O-1 for industrial applications, its chemical structure must be elucidated. This study also analyzed the changes in the wetting properties of different surfaces conditioned with AMS H2O-1 and demonstrated the effect of AMS H2O-1 on sulfate reducing bacteria cells. A lipopeptide mixture from AMS H2O-1 was partially purified on a silica gel column and identified via mass spectrometry (ESI-MS). It comprises four major components that range in size from 1007 to 1049 Da. The lipid moiety contains linear and branched β-hydroxy fatty acids that range in length from C13 to C16. The peptide moiety contains seven amino acids identified as Glu-Leu-Leu-Val-Asp-Leu-Leu.Transmission electron microscopy revealed cell membrane alteration of sulfate reducing bacteria after AMS H2O-1 treatment at the minimum inhibitory concentration (5 μg/ml). Cytoplasmic electron dense inclusions were observed in treated cells but not in untreated cells. AMS H2O-1 enhanced the osmosis of sulfate reducing bacteria cells and caused the leakage of the intracellular contents. In addition, contact angle measurements indicated that different surfaces conditioned by AMS H2O-1 were less hydrophobic and more electron-donor than untreated surfaces. AMS H2O-1 is a mixture of four surfactin-like homologues, and its biocidal activity and surfactant properties suggest that this compound may be a good candidate for sulfate reducing bacteria control. Thus, it is a potential alternative to the chemical biocides or surface coating agents currently used to prevent SRB growth in petroleum industries.

Androgen and Progesterone Receptors Are Targets for Bisphenol A (BPA), 4-Methyl-2,4-bis-(P-Hydroxyphenyl)Pent-1-Ene--A Potent Metabolite of BPA, and 4-Tert-Octylphenol: A Computational Insight.

PubMed

Rehan, Mohd; Ahmad, Ejaz; Sheikh, Ishfaq A; Abuzenadah, Adel M; Damanhouri, Ghazi A; Bajouh, Osama S; AlBasri, Samera F; Assiri, Mansour M; Beg, Mohd A

2015-01-01

Exposure to toxic industrial chemicals that have capacity to disrupt the endocrine system, also known as endocrine disrupting chemicals (EDCs), has been increasingly associated with reproductive problems in human population. Bisphenol A (BPA; 4,4'-(propane-2,2-diyl)diphenol) and 4-tert-octylphenol (OP; 4-(1,1,3,3-tetramethylbutyl)phenol) are among the most common environmental contaminants possessing endocrine disruption properties and are present in plastics, epoxy resins, detergents and other commercial products of common personal and industrial use. A metabolite of BPA, 4-Methyl-2,4-bis(4-hydroxyphenyl)pent-1-ene (MBP) is about 1000 times more biologically active compared to BPA. Epidemiological, clinical, and experimental studies have shown association of BPA and OP with adverse effects on male and female reproductive system in human and animals. The endocrine disruption activity can occur through multiple pathways including binding to steroid receptors. Androgen receptor (AR) and progesterone receptor (PR) are critical for reproductive tract growth and function. Structural binding characterization of BPA, MBP, and OP with AR and PR using molecular docking simulation approaches revealed novel interactions of BPA with PR, and MBP and OP with AR and PR. For BPA, MBP, and OP, five AR interacting residues Leu-701, Leu-704, Asn-705, Met-742, and Phe-764 overlapped with those of native AR ligand testosterone, and four PR interacting residues Leu-715, Leu-718, Met-756, and Met-759 overlapped with those of PR co-complex ligand, norethindrone. For both the receptors the binding strength of MBP was maximum among the three compounds. Thus, these compounds have the potential to block or interfere in the binding of the endogenous native AR and PR ligands and, hence, resulting in dysfunction. The knowledge of the key interactions and the important amino-acid residues also allows better prediction of potential of xenobiotic molecules for disrupting AR- and PR-mediated pathways, thus, helping in design of less potent alternatives for commercial use.

Androgen and Progesterone Receptors Are Targets for Bisphenol A (BPA), 4-Methyl-2,4-bis-(P-Hydroxyphenyl)Pent-1-Ene—A Potent Metabolite of BPA, and 4-Tert-Octylphenol: A Computational Insight

PubMed Central

Rehan, Mohd; Ahmad, Ejaz; Sheikh, Ishfaq A.; Abuzenadah, Adel M.; Damanhouri, Ghazi A.; Bajouh, Osama S.; AlBasri, Samera F.; Assiri, Mansour M.; Beg, Mohd A.

2015-01-01

Exposure to toxic industrial chemicals that have capacity to disrupt the endocrine system, also known as endocrine disrupting chemicals (EDCs), has been increasingly associated with reproductive problems in human population. Bisphenol A (BPA; 4,4'-(propane-2,2-diyl)diphenol) and 4-tert-octylphenol (OP; 4-(1,1,3,3-tetramethylbutyl)phenol) are among the most common environmental contaminants possessing endocrine disruption properties and are present in plastics, epoxy resins, detergents and other commercial products of common personal and industrial use. A metabolite of BPA, 4-Methyl-2,4-bis(4-hydroxyphenyl)pent-1-ene (MBP) is about 1000 times more biologically active compared to BPA. Epidemiological, clinical, and experimental studies have shown association of BPA and OP with adverse effects on male and female reproductive system in human and animals. The endocrine disruption activity can occur through multiple pathways including binding to steroid receptors. Androgen receptor (AR) and progesterone receptor (PR) are critical for reproductive tract growth and function. Structural binding characterization of BPA, MBP, and OP with AR and PR using molecular docking simulation approaches revealed novel interactions of BPA with PR, and MBP and OP with AR and PR. For BPA, MBP, and OP, five AR interacting residues Leu-701, Leu-704, Asn-705, Met-742, and Phe-764 overlapped with those of native AR ligand testosterone, and four PR interacting residues Leu-715, Leu-718, Met-756, and Met-759 overlapped with those of PR co-complex ligand, norethindrone. For both the receptors the binding strength of MBP was maximum among the three compounds. Thus, these compounds have the potential to block or interfere in the binding of the endogenous native AR and PR ligands and, hence, resulting in dysfunction. The knowledge of the key interactions and the important amino-acid residues also allows better prediction of potential of xenobiotic molecules for disrupting AR- and PR-mediated pathways, thus, helping in design of less potent alternatives for commercial use. PMID:26379041

Multi-allergen Quantitation and the Impact of Thermal Treatment in Industry-Processed Baked Goods by ELISA and Liquid Chromatography-Tandem Mass Spectrometry.

PubMed

Parker, Christine H; Khuda, Sefat E; Pereira, Marion; Ross, Mark M; Fu, Tong-Jen; Fan, Xuebin; Wu, Yan; Williams, Kristina M; DeVries, Jonathan; Pulvermacher, Brian; Bedford, Binaifer; Zhang, Xi; Jackson, Lauren S

2015-12-16

Undeclared food allergens account for 30-40% of food recalls in the United States. Compliance with ingredient labeling regulations and the implementation of effective manufacturing allergen control plans require the use of reliable methods for allergen detection and quantitation in complex food products. The objectives of this work were to (1) produce industry-processed model foods incurred with egg, milk, and peanut allergens, (2) compare analytical method performance for allergen quantitation in thermally processed bakery products, and (3) determine the effects of thermal treatment on allergen detection. Control and allergen-incurred cereal bars and muffins were formulated in a pilot-scale industry processing facility. Quantitation of egg, milk, and peanut in incurred baked goods was compared at various processing stages using commercial enzyme-linked immunosorbent assay (ELISA) kits and a novel multi-allergen liquid chromatography (LC)-tandem mass spectrometry (MS/MS) multiple-reaction monitoring (MRM) method. Thermal processing was determined to negatively affect the recovery and quantitation of egg, milk, and peanut to different extents depending on the allergen, matrix, and analytical test method. The Morinaga ELISA and LC-MS/MS quantitative methods reported the highest recovery across all monitored allergens, whereas the ELISA Systems, Neogen BioKits, Neogen Veratox, and R-Biopharm ELISA Kits underperformed in the determination of allergen content of industry-processed bakery products.

HS-GC-MS method for the analysis of fragrance allergens in complex cosmetic matrices.

PubMed

Desmedt, B; Canfyn, M; Pype, M; Baudewyns, S; Hanot, V; Courselle, P; De Beer, J O; Rogiers, V; De Paepe, K; Deconinck, E

2015-01-01

Potential allergenic fragrances are part of the Cosmetic Regulation with labelling and concentration restrictions. This means that they have to be declared on the ingredients list, when their concentration exceeds the labelling limit of 10 ppm or 100 ppm for leave-on or rinse-off cosmetics, respectively. Labelling is important regarding consumer safety. In this way, sensitised people towards fragrances might select their products based on the ingredients list to prevent elicitation of an allergic reaction. It is therefore important to quantify potential allergenic ingredients in cosmetic products. An easy to perform liquid extraction was developed, combined with a new headspace GC-MS method. The latter was capable of analysing 24 volatile allergenic fragrances in complex cosmetic formulations, such as hydrophilic (O/W) and lipophilic (W/O) creams, lotions and gels. This method was successfully validated using the total error approach. The trueness deviations for all components were smaller than 8%, and the expectation tolerance limits did not exceed the acceptance limits of ± 20% at the labelling limit. The current methodology was used to analyse 18 cosmetic samples that were already identified as being illegal on the EU market for containing forbidden skin whitening substances. Our results showed that these cosmetic products also contained undeclared fragrances above the limit value for labelling, which imposes an additional health risk for the consumer. Copyright © 2014 Elsevier B.V. All rights reserved.

Frequency of the AGT Pro11Leu polymorphism in humans: Does diet matter?

PubMed

Ségurel, Laure; Lafosse, Sophie; Heyer, Evelyne; Vitalis, Renaud

2010-01-01

The Pro11Leu substitution in the AGXT gene, which causes primary hyperoxaluria type 1, is found with high frequency in some human populations (e.g., 5-20% in Caucasians). It has been suggested that this detrimental mutation could have been positively selected in populations with a meat-rich diet. In order to test this hypothesis, we investigated the occurrence of Pro11Leu in both herder and agriculturalist populations from Central Asia. We found a lower frequency of this detrimental mutation in herders, whose diet is more meat-rich, as compared to agriculturalists, which therefore challenges the universality of the previous claim. Furthermore, when combining our original data with previously published results, we could show that the worldwide genetic differentiation measured at the Pro11Leu polymorphism does not depart from neutrality. Hence, the distribution of the variation observed in the AGXT gene could be due to demographic history, rather than local adaptation to diet.

JPRS Report, Near East & South Asia

DTIC Science & Technology

1990-11-08

INTERNATIONAL AFFAIRS Undeclared Strategic Agendas in Gulf 91AE0085A Tel Aviv YEDI’OT AHARONOT in Hebrew 30 Oct 90 pp 7, 25 [Article by Ron Ben...faithful representative of the " bible belt" in the southern United States. It is currently difficult to know who initiated the Saudi deals. Was it the...state. JPRS-NEA-90-066 8 NOVEMBER 1990 NEAR EAST 13 ISRAEL Columnist Examines U.S. Middle East Policy 91AE0038B Tel Aviv MA’ARIV in Hebrew

Molecular polygamy: The promiscuity of l-phenylalanyl-tRNA-synthetase triggers misincorporation of meta- and ortho-tyrosine in monoclonal antibodies expressed by Chinese hamster ovary cells.

PubMed

Popp, Oliver; Larraillet, Vincent; Kettenberger, Hubert; Gorr, Ingo H; Hilger, Maximiliane; Lipsmeier, Florian; Zeck, Anne; Beaucamp, Nicola

2015-06-01

In-depth analytical characterization of biotherapeutics originating from different production batches is mandatory to ensure product safety and consistent molecule efficacy. Previously, we have shown unintended incorporation of tyrosine (Tyr) and leucine/isoleucine (Leu/Ile) at phenylalanine (Phe) positions in a recombinant produced monoclonal antibody (mAb) using an orthogonal MASCOT/SIEVE based approach for mass spectrometry data analysis. The misincorporation could be avoided by sufficient supply of phenylalanine throughout the process. Several non-annotated signals in the primarily chromatographic peptide separation step for apparently single Phe→Tyr sequence variants (SVs) suggest a role for isobar tyrosine isoforms. Meta- and ortho-Tyr are spontaneously generated during aerobic fed-batch production processes using Chinese hamster ovary (CHO) cell lines. Process induced meta- and ortho-Tyr but not proteinogenic para-Tyr are incorporated at Phe locations in Phe-starved CHO cultures expressing a recombinant mAb. Furthermore, meta- and ortho-Tyr are preferably misincorporated over Leu. Structural modeling of the l-phenylalanyl-tRNA-synthetase (PheRS) substrate activation site indicates a possible fit of non-cognate ortho-Tyr and meta-Tyr substrates. Dose-dependent misincorporations of Tyr isoforms support the hypothesis that meta- and ortho-Tyr are competing, alternative substrates for PheRS in CHO processes. Finally, easily accessible at-line surrogate markers for Phe→Tyr SV formation in biotherapeutic production were defined by the calculation of critical ratios for meta-Tyr/Phe and ortho-Tyr/Phe to support early prediction of SV probability, and finally, to allow for immediate process controlled Phe→Tyr SV prevention. © 2014 Wiley Periodicals, Inc.

NADH Dehydrogenase Subunit-2 237 Leu/Met Polymorphism Modulates the Effects of Coffee Consumption on the Risk of Hypertension in Middle-Aged Japanese Men

PubMed Central

Kokaze, Akatsuki; Ishikawa, Mamoru; Matsunaga, Naomi; Karita, Kanae; Yoshida, Masao; Ohtsu, Tadahiro; Shirasawa, Takako; Sekii, Hideaki; Ito, Taku; Kawamoto, Teruyoshi; Takashima, Yutaka

2009-01-01

Background Habitual coffee consumption has been reported to lower blood pressure in the Japanese population. The NADH dehydrogenase subunit-2 237 leucine/methionine (ND2-237 Leu/Met) polymorphism is associated with longevity and modifies the effects of alcohol consumption on blood pressure in the Japanese population. The objective of this study was to determine whether this polymorphism also modifies the effects of coffee consumption on blood pressure or the risk of hypertension in middle-aged Japanese men. Methods A total of 398 men (mean age ± standard deviation, 53.8 ± 7.8 years) were selected from among individuals visiting the hospital for regular medical check-ups. Hypertension was defined as a systolic blood pressure ≥140 mm Hg, diastolic blood pressure ≥90 mm Hg, or antihypertensive drug treatment. Polymerase chain reaction-restriction fragment length polymorphism using the restriction enzyme AluI was performed to determine ND2-237 Leu/Met genotype. Results In subjects with ND2-237Leu, coffee consumption was significantly and negatively associated with diastolic blood pressure (P = 0.007). The odds ratio (OR) for hypertension was significantly lower in subjects with ND2-237Leu who consumed 2 or 3 cups of coffee per day than in those who consumed less than 1 cup of coffee per day (OR, 0.517; 95% confidence interval [CI], 0.276 to 0.968; P = 0.039). After adjustment, the OR remained significant (OR = 0.399; 95% CI, 0.184 to 0.869; P = 0.020). Moreover, after adjustment, the OR was significantly lower in subjects with ND2-237Leu who consumed more than 4 cups of coffee per day than in those who consumed less than 1 cup of coffee per day (OR, 0.246; 95% CI, 0.062 to 0.975; P = 0.046). However, the association between ND2-237Met genotype and hypertension did not depend on coffee consumption. Conclusions The present results suggest that the ND2-237 Leu/Met polymorphism modulates the effects of coffee consumption on hypertension risk in middle-aged Japanese men. PMID:19667492

Conversion of leucine to β‐hydroxy‐β‐methylbutyrate by α‐keto isocaproate dioxygenase is required for a potent stimulation of protein synthesis in L6 rat myotubes

PubMed Central

Vílchez, José D.; Salto, Rafael; Manzano, Manuel; Sevillano, Natalia; Campos, Nefertiti; Argilés, Josep M.; Rueda, Ricardo; López‐Pedrosa, José M.

2015-01-01

Abstract Background L‐Leu and its metabolite β‐hydroxy‐β‐methylbutyrate (HMB) stimulate muscle protein synthesis enhancing the phosphorylation of proteins that regulate anabolic signalling pathways. Alterations in these pathways are observed in many catabolic diseases, and HMB and L‐Leu have proven their anabolic effects in in vivo and in vitro models. The aim of this study was to compare the anabolic effects of L‐Leu and HMB in myotubes grown in the absence of any catabolic stimuli. Methods Studies were conducted in vitro using rat L6 myotubes under normal growth conditions (non‐involving L‐Leu‐deprived conditions). Protein synthesis and mechanistic target of rapamycin signalling pathway were determined. Results Only HMB was able to increase protein synthesis through a mechanism that involves the phosphorylation of the mechanistic target of rapamycin as well as its downstream elements, pS6 kinase, 4E binding protein‐1, and eIF4E. HMB was significantly more effective than L‐Leu in promoting these effects through an activation of protein kinase B/Akt. Because the conversion of L‐Leu to HMB is limited in muscle, L6 cells were transfected with a plasmid that codes for α‐keto isocaproate dioxygenase, the key enzyme involved in the catabolic conversion of α‐keto isocaproate into HMB. In these transfected cells, L‐Leu was able to promote protein synthesis and mechanistic target of rapamycin regulated pathway activation equally to HMB. Additionally, these effects of leucine were reverted to a normal state by mesotrione, a specific inhibitor of α‐keto isocaproate dioxygenase. Conclusion Our results suggest that HMB is an active L‐Leu metabolite able to maximize protein synthesis in skeletal muscle under conditions, in which no amino acid deprivation occurred. It may be proposed that supplementation with HMB may be very useful to stimulate protein synthesis in wasting conditions associated with chronic diseases, such as cancer or chronic heart failure. PMID:27065075

Activation of the AMPK/Sirt1 pathway by a leucine-metformin combination increases insulin sensitivity in skeletal muscle, and stimulates glucose and lipid metabolism and increases life span in Caenorhabditis elegans.

PubMed

Banerjee, Jheelam; Bruckbauer, Antje; Zemel, Michael B

2016-11-01

We have previously shown leucine (Leu) to activate Sirt1 by lowering its K M for NAD + , thereby amplifying the effects of other sirtuin activators and improving insulin sensitivity. Metformin (Met) converges on this pathway both indirectly (via AMPK) and by direct activation of Sirt1, and we recently found Leu to synergize with Met to improve insulin sensitivity and glycemic control while achieving ~80% dose-reduction in diet-induced obese mice. Accordingly, we sought here to define the mechanism of this interaction. Muscle cells C2C12 and liver cells HepG2 were used to test the effect of Met-Leu on Sirt1 activation. Caenorhabditis elegans was used for glucose utilization and life span studies. Leu (0.5mmol/L)+Met (50-100μmol/L) synergistically activated Sirt1 (p<0.001) at low (≤100μmol/L) NAD + levels while Met exerted no independent effect. This was associated with an increase in AMPK and ACC, phosphorylation, and increased fatty acid oxidation, which was prevented by AMPK or Sirt inhibition or silencing. Met-Leu also increased P-IRS1/IRS1 and P-AKT/AKT and in insulin-independent glucose disposal in myotubes (~50%, p<0.002) evident within 30 min as well as a 60% reduction in insulin EC 50 . In addition, in HepG2 liver cells nuclear CREB regulated transcription coactivator 2 (CRTC2) protein expression and phosphorylation of glycogen synthase was decreased, while glycogen synthase kinase phosphorylation was increased indicating decreased gluconeogenesis and glycogen synthesis. We utilized C. elegans to assess the metabolic consequences of this interaction. Exposure to high glucose impaired glucose utilization and shortened life span by ~25%, while addition of Leu+Met to high glucose worms increased median and maximal life span by 29 and 15%, respectively (p=0.023), restored normal glucose utilization and increased fat oxidation ~two-fold (p<0.005), while metformin exerted no independent effect at any concentration (0.1-0.5mmol/L). Thus, Leu and Met synergize to enable Sirt1 activation at low NAD + concentrations (typical of energy replete states). Sirt1 and AMPK activations are required for Met-Leu's full action, which result in improvements in energy metabolism and insulin sensitivity. Copyright © 2016 Elsevier Inc. All rights reserved.

Evaluation of the leucine incorporation technique for detection of pollution-induced community tolerance to copper in a long-term agricultural field trial with urban waste fertilizers.

PubMed

Lekfeldt, Jonas Duus Stevens; Magid, Jakob; Holm, Peter E; Nybroe, Ole; Brandt, Kristian Koefoed

2014-11-01

Copper (Cu) is known to accumulate in agricultural soils receiving urban waste products as fertilizers. We here report the use of the leucine incorporation technique to determine pollution-induced community tolerance (Leu-PICT) to Cu in a long-term agricultural field trial. A significantly increased bacterial community tolerance to Cu was observed for soils amended with organic waste fertilizers and was positively correlated with total soil Cu. However, metal speciation and whole-cell bacterial biosensor analysis demonstrated that the observed PICT responses could be explained entirely by Cu speciation and bioavailability artifacts during Leu-PICT detection. Hence, the agricultural application of urban wastes (sewage sludge or composted municipal waste) simulating more than 100 years of use did not result in sufficient accumulation of Cu to select for Cu resistance. Our findings also have implications for previously published PICT field studies and demonstrate that stringent PICT detection criteria are needed for field identification of specific toxicants. Copyright © 2014 Elsevier Ltd. All rights reserved.

Field test of short-notice random inspections for inventory-change verification at a low-enriched-uranium fuel-fabrication plant: Preliminary summary

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fishbone, L.G.; Moussalli, G.; Naegele, G.

1994-04-01

An approach of short-notice random inspections (SNRIs) for inventory-change verification can enhance the effectiveness and efficiency of international safeguards at natural or low-enriched uranium (LEU) fuel fabrication plants. According to this approach, the plant operator declares the contents of nuclear material items before knowing if an inspection will occur to verify them. Additionally, items about which declarations are newly made should remain available for verification for an agreed time. This report details a six-month field test of the feasibility of such SNRIs which took place at the Westinghouse Electric Corporation Commercial Nuclear Fuel Division. Westinghouse personnel made daily declarations aboutmore » both feed and product items, uranium hexafluoride cylinders and finished fuel assemblies, using a custom-designed computer ``mailbox``. Safeguards inspectors from the IAEA conducted eight SNRIs to verify these declarations. Items from both strata were verified during the SNRIs by means of nondestructive assay equipment. The field test demonstrated the feasibility and practicality of key elements of the SNRI approach for a large LEU fuel fabrication plant.« less

Neurotensin-metabolizing peptidases in rat fundus plasma membranes.

PubMed

Checler, F; Barelli, H; Kwan, C Y; Kitabgi, P; Vincent, J P

1987-08-01

The mechanisms by which neurotensin (NT) was inactivated by rat fundus plasma membranes were characterized. Primary inactivating cleavages occurred at the Arg8-Arg9, Pro10-Tyr11, and Ile12-Leu13 peptidyl bonds. Hydrolysis at the Arg8-Arg9 bond was fully abolished by the use of N-[1(R,S)-carboxy-2-phenylethyl]-alanyl-alanyl-phenylalanine-p- aminobenzoate, a result indicating the involvement at this site of a recently purified soluble metallopeptidase. Hydrolysis of the Pro10-Tyr11 bond was totally resistant to N-benzyloxycarbonyl-prolyl-prolinal and thiorphan, an observation suggesting that the peptidase responsible for this cleavage was different from proline endopeptidase and endopeptidase 24.11 and might correspond to a NT-degrading neutral metallopeptidase recently isolated from rat brain synaptic membranes. The enzyme acting at the Ile12-Leu13 bond has not yet been identified. Secondary cleavages occurring on NT degradation products were mainly generated by bestatin-sensitive aminopeptidases and post-proline dipeptidyl aminopeptidase. The content in NT-metabolizing peptidases present in rat fundus plasma membranes is compared with that previously established for purified rat brain synaptic membranes.

Compendium of Phase-I Mini-SHINE Experiments

DOE Office of Scientific and Technical Information (OSTI.GOV)

Youker, Amanda J.; Chemerisov, Sergey D.; Tkac, Peter

Argonne National Laboratory is assisting SHINE Medical Technologies in their efforts to develop the technology to become a domestic Mo-99 producer using low-enriched uranium (LEU). Mini-SHINE experiments are being performed with the high-current electron linear accelerator (linac) at Argonne. The target solution is a 90-150 g-U/L LEU uranyl sulfate at pH 1. In Phase 1, the convertor was tantalum with a maximum beam power on the convertor of 10 kW, and the target solution was limited to 5 L. This configuration generated a peak fission power density of 0.05 W/mL. Nine experiments were performed between February and October 2015. Resultsmore » are reported and discussed for each experiment regarding the off-gas analysis system, the sampling and Mo-recovery operation, and the Mo-product concentration and purification system. In Phase 2, the convertor will be depleted uranium; beam power will increase to 20 kW; and the solution volume will be 18 L. This configuration will generate a fission power density of up to 1 W/mL.« less

Hexapeptide fragment of carcinoembryonic antigen which acts as an agonist of heterogeneous ribonucleoprotein M.

PubMed

Palermo, Nicholas Y; Thomas, Peter; Murphy, Richard F; Lovas, Sándor

2012-04-01

Colorectal cancers with metastatic potential secrete the glycoprotein carcinoembryonic antigen (CEA). CEA has been implicated in colorectal cancer metastasis by inducing Kupffer cells to produce inflammatory cytokines which, in turn, make the hepatic micro-environment ideal for tumor cell implantation. CEA binds to the heterogeneous ribonucleoprotein M (hnRNP M) which acts as a cell surface receptor in Kupffer cells. The amino acid sequence in CEA, which binds the hnRNP M receptor, is Tyr-Pro-Glu-Leu-Pro-Lys. In this study, the structure of Ac-Tyr-Pro-Glu-Leu-Pro-Lys-NH₂ (YPELPK) was investigated using electronic circular dichroism, vibrational circular dichroism, and molecular dynamics simulations. The binding of the peptide to hnRNP M was also investigated using molecular docking calculations. The biological activity of YPELPK was studied using differentiated human THP-1 cells, which express hnRNP M on their surface and secrete IL-6 when stimulated by CEA. YPELPK forms a stable polyproline-II helix and stimulates IL-6 production of THP-1 cells at micromolar concentrations. Copyright © 2012 European Peptide Society and John Wiley & Sons, Ltd.

Effect of herbicide resistance endowing Ile-1781-Leu and Asp-2078-Gly ACCase gene mutations on ACCase kinetics and growth traits in Lolium rigidum

PubMed Central

Vila-Aiub, Martin M.; Yu, Qin; Han, Heping; Powles, Stephen B.

2015-01-01

The rate of herbicide resistance evolution in plants depends on fitness traits endowed by alleles in both the presence and absence (resistance cost) of herbicide selection. The effect of two Lolium rigidum spontaneous homozygous target-site resistance-endowing mutations (Ile-1781-Leu, Asp-2078-Gly) on both ACCase activity and various plant growth traits have been investigated here. Relative growth rate (RGR) and components (net assimilation rate, leaf area ratio), resource allocation to different organs, and growth responses in competition with a wheat crop were assessed. Unlike plants carrying the Ile-1781-Leu resistance mutation, plants homozygous for the Asp-2078-Gly mutation exhibited a significantly lower RGR (30%), which translated into lower allocation of biomass to roots, shoots, and leaves, and poor responses to plant competition. Both the negligible and significant growth reductions associated, respectively, with the Ile-1781-Leu and Asp-2078-Gly resistance mutations correlated with their impact on ACCase activity. Whereas the Ile-1781-Leu mutation showed no pleiotropic effects on ACCase kinetics, the Asp-2078-Gly mutation led to a significant reduction in ACCase activity. The impaired growth traits are discussed in the context of resistance costs and the effects of each resistance allele on ACCase activity. Similar effects of these two particular ACCase mutations on the ACCase activity of Alopecurus myosuroides were also confirmed. PMID:26019257

Characterization of Gly-D-Phe, Gly-L-Leu, and D-Phe as affinity ligands to thermolysin.

PubMed

Yasukawa, Kiyoshi; Kusano, Masayuki; Nakamura, Koji; Inouye, Kuniyo

2006-04-01

In this study, glycyl-D-phenylalanine (Gly-D-Phe), glycyl-L-leucine (Gly-L-Leu), and D-phenylalanine (D-Phe) were characterized for their abilities as affinity ligands to thermolysin. Each of the ligands was immobilized to the resin. The optimum pH for adsorption of thermolysin is 5.0-6.0 for each of the ligands. By the affinity column chromatography in which 2mg thermolysin was applied onto 4 ml volume of the resins at pH 5.5, the adsorption ratios based on casein hydrolysis activity were 100% for each of the ligands. However, the adsorption ratios of the resins containing Gly-L-Leu and D-Phe, unlike that of Gly-D-Phe, were progressively decreased with increasing the amounts of thermolysin applied to the column. Measurement of adsorption isotherms showed that the association constant to thermolysin at pH 5.5 of the resins containing Gly-D-Phe was (3.3+/-0.8)x10(5)M(-1), while those of Gly-L-Leu and D-Phe were approximately ten times less. This result is coincident with the observations of performances in affinity column chromatography. On the other hand, maximum thermolysin binding capacities were almost the same among the resins examined. These results indicate that Gly-D-Phe is more suitable than Gly-L-Leu and D-Phe as an affinity ligand for purification of thermolysin.

Transforming growth factor beta1 gene variation Leu10Pro affects secretion and function in hepatic cells.

PubMed

Gu, Xing; Ji, Xin; Shi, Le-Hua; Yi, Chang-Hong; Zhao, Yun-Peng; Wang, Ai-Hua; Lu, Lun-Gen; Yu, Wen-Bo; Gao, Chun-Fang

2012-11-01

Our previous work revealed transforming growth factor beta1 (TGFβ1) gene polymorphisms are associated with susceptibility to hepatocellular carcinoma and liver cirrhosis. However, no further study of functional substitution in hepatic cells has yet been reported. This study was designed to uncover the functional mechanisms of TGFβ1 gene polymorphisms in the pathogenesis of liver diseases. Two recombinant TGFβ1 expression plasmids containing TGFβ1 codon 10 Leu/Pro variation were constructed with CMV promoter and transfected into human hepatoma cell lines (HepG2 and SMMU 7721), hepatic stellate cells (LX-2), and immortalized hepatocytes (L02). The secretion capacities of TGFβ1 protein in the transfected cells were determined by ELISA. Apoptosis, proliferative activity, and expression of CD 105, CD83, and CD80 were also measured by use of flow cytometry. The ELISA results showed that cells transfected with CMV-Pro10 were more capable of TGFβ1 secretion than those transfected with CMV-Leu10. Functionally, CMV-Pro10 was more apoptosis-protective and induced more proliferation than CMV-Leu10 in transfected hepatic cells. Pro10 up-regulated expression of CD105 and down-regulated expression of CD83. TGFβ1 gene Leu10Pro variation in signal peptide has significant effects on TGFβ1 secretion and functions in hepatic cells.

Monte Carlo Shielding Comparative Analysis Applied to TRIGA HEU and LEU Spent Fuel Transport

NASA Astrophysics Data System (ADS)

Margeanu, C. A.; Margeanu, S.; Barbos, D.; Iorgulis, C.

2010-12-01

The paper is a comparative study of LEU and HEU fuel utilization effects for the shielding analysis during spent fuel transport. A comparison against the measured data for HEU spent fuel, available from the last stage of spent fuel repatriation fulfilled in the summer of 2008, is also presented. All geometrical and material data for the shipping cask were considered according to NAC-LWT Cask approved model. The shielding analysis estimates radiation doses to shipping cask wall surface, and in air at 1 m and 2 m, respectively, from the cask, by means of 3D Monte Carlo MORSE-SGC code. Before loading into the shipping cask, TRIGA spent fuel source terms and spent fuel parameters have been obtained by means of ORIGEN-S code. Both codes are included in ORNL's SCALE 5 programs package. The actinides contribution to total fuel radioactivity is very low in HEU spent fuel case, becoming 10 times greater in LEU spent fuel case. Dose rates for both HEU and LEU fuel contents are below regulatory limits, LEU spent fuel photon dose rates being greater than HEU ones. Comparison between HEU spent fuel theoretical and measured dose rates in selected measuring points shows a good agreement, calculated values being greater than the measured ones both to cask wall surface (about 34% relative difference) and in air at 1 m distance from cask surface (about 15% relative difference).

Neurospora tryptophan synthase: N-terminal analysis and the sequence of the pyridoxal phosphate active site peptide

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pratt, M.L.; Hsu, P.Y.; DeMoss, J.A.

1986-05-01

Tryptophan synthase (TS), which catalyzes the final step of tryptophan biosynthesis, is a multifunctional protein requiring pyridoxal phosphate (B6P) for two of its three distinct enzyme activities. TS from Neurospora has a blocked N-terminal, is a homodimer of 150 KDa and binds one mole of B6P per mole of subunit. The authors shown the N-terminal residue to be acyl-serine. The B6P-active site of holoenzyme was labelled by reduction of the B6P-Schiff base with (/sup 3/H)-NaBH/sub 4/, and resulted in a proportionate loss of activity in the two B6P-requiring reactions. SDS-polyacrylamide gel electrophoresis of CNBr-generated peptides showed the labelled, active sitemore » peptide to be 6 KDa. The sequence of this peptide, purified to apparent homogeneity by a combination of C-18 reversed phase and TSK gel filtration HPLC is: gly-arg-pro-gly-gln-leu-his-lys-ala-glu-arg-leu-thr-glu-tyr-ala-gly-gly-ala-gln-ile-xxx-leu-lys-arg-glu-asp-leu-asn-his-xxx-gly-xxx-his-/sub ***/-ile-asn-asn-ala-leu. Although four residues (xxx, /sub ***/) are unidentified, this peptide is minimally 78% homologous with the corresponding peptide from yeast TS, in which residue (/sub ***/) is the lysine that binds B6P.« less

Neutronics and Thermal Hydraulics Study for Using a Low-Enriched Uranium Core in the Advanced Test Reactor -- 2008 Final Report

DOE Office of Scientific and Technical Information (OSTI.GOV)

G. S. Chang; M. A. Lillo; R. G. Ambrosek

2008-06-01

The Advanced Test Reactor (ATR) is a high power density and high neutron flux research reactor operating in the United States. Powered with highly enriched uranium (HEU), the ATR has a maximum thermal power rating of 250 MWth. Because of the large test volumes located in high flux areas, the ATR is an ideal candidate for assessing the feasibility of converting an HEU driven reactor to a low-enriched core. The present work investigates the necessary modifications and evaluates the subsequent operating effects of this conversion. A detailed plate-by-plate MCNP ATR 1/8th core model was developed and validated for a fuelmore » cycle burnup comparison analysis. Using the current HEU U 235 enrichment of 93.0 % as a baseline, an analysis was performed to determine the low-enriched uranium (LEU) density and U-235 enrichment required in the fuel meat to yield an equivalent K-eff versus effective full power days (EFPDs) between the HEU and the LEU cores. The MCNP ATR 1/8th core model was used to optimize the U 235 loading in the LEU core, such that the differences in K-eff and heat flux profiles between the HEU and LEU cores were minimized. The depletion methodology MCWO was used to calculate K-eff versus EFPDs in this paper. The MCWO-calculated results for the LEU demonstrated adequate excess reactivity such that the K-eff versus EFPDs plot is similar to the ATR reference HEU case study. Each HEU fuel element contains 19 fuel plates with a fuel meat thickness of 0.508 mm (20 mil). In this work, the proposed LEU (U-10Mo) core conversion case with nominal fuel meat thickness of 0.330 mm (13 mil) and U-235 enrichment of 19.7 wt% is used to optimize the radial heat flux profile by varying the fuel meat thickness from 0.191 mm (7.0 mil) to 0.330 mm (13.0 mil) at the inner 4 fuel plates (1-4) and outer 4 fuel plates (16-19). A 0.8g of Boron-10, a burnable absorber, was added in the inner and outer plates to reduce the initial excess reactivity, and the peak to average ratio of the inner/outer heat flux more effectively. Because the B-10 (n,a) reaction will produce Helium-4 (He-4), which might degrade the LEU foil type fuel performance, an alternative absorber option is proposed. The proposed LEU case study will have 6.918 g of Cadmium (Cd) mixed with the LEU at the inner 4 fuel plates (1-4) and outer 4 fuel plates (16-19) as a burnable absorber to achieve peak to average ratios similar to those for the ATR reference HEU case study.« less

Prolonged leucine infusion differentially affects tissue protein synthesis in neonatal pigs

USDA-ARS?s Scientific Manuscript database

Leucine (Leu) acutely stimulates protein synthesis by activating the mammalian target of rapamycin complex 1 (mTORC1) pathway. To determine whether Leu can stimulate protein synthesis in muscles of different fiber types and visceral tissues of the neonate for a prolonged period and to determine the ...

Engineering proximal vs. distal heme-NO coordination via dinitrosyl dynamics: implications for NO sensor design.

PubMed

Kekilli, Demet; Petersen, Christine A; Pixton, David A; Ghafoor, Dlzar D; Abdullah, Gaylany H; Dworkowski, Florian S N; Wilson, Michael T; Heyes, Derren J; Hardman, Samantha J O; Murphy, Loretta M; Strange, Richard W; Scrutton, Nigel S; Andrew, Colin R; Hough, Michael A

2017-03-01

Proximal vs. distal heme-NO coordination is a novel strategy for selective gas response in heme-based NO-sensors. In the case of Alcaligenes xylosoxidans cytochrome c' (AXCP), formation of a transient distal 6cNO complex is followed by scission of the trans Fe-His bond and conversion to a proximal 5cNO product via a putative dinitrosyl species. Here we show that replacement of the AXCP distal Leu16 residue with smaller or similar sized residues (Ala, Val or Ile) traps the distal 6cNO complex, whereas Leu or Phe residues lead to a proximal 5cNO product with a transient or non-detectable distal 6cNO precursor. Crystallographic, spectroscopic, and kinetic measurements of 6cNO AXCP complexes show that increased distal steric hindrance leads to distortion of the Fe-N-O angle and flipping of the heme 7-propionate. However, it is the kinetic parameters of the distal NO ligand that determine whether 6cNO or proximal 5cNO end products are formed. Our data support a 'balance of affinities' mechanism in which proximal 5cNO coordination depends on relatively rapid release of the distal NO from the dinitrosyl precursor. This mechanism, which is applicable to other proteins that form transient dinitrosyls, represents a novel strategy for 5cNO formation that does not rely on an inherently weak Fe-His bond. Our data suggest a general means of engineering selective gas response into biologically-derived gas sensors in synthetic biology.

Meat authentication: a new HPLC-MS/MS based method for the fast and sensitive detection of horse and pork in highly processed food.

PubMed

von Bargen, Christoph; Brockmeyer, Jens; Humpf, Hans-Ulrich

2014-10-01

Fraudulent blending of food products with meat from undeclared species is a problem on a global scale, as exemplified by the European horse meat scandal in 2013. Routinely used methods such as ELISA and PCR can suffer from limited sensitivity or specificity when processed food samples are analyzed. In this study, we have developed an optimized method for the detection of horse and pork in different processed food matrices using MRM and MRM(3) detection of species-specific tryptic marker peptides. Identified marker peptides were sufficiently stable to resist thermal processing of different meat products and thus allow the sensitive and specific detection of pork or horse in processed food down to 0.24% in a beef matrix system. In addition, we were able to establish a rapid 2-min extraction protocol for the efficient protein extraction from processed food using high molar urea and thiourea buffers. Together, we present here the specific and sensitive detection of horse and pork meat in different processed food matrices using MRM-based detection of marker peptides. Notably, prefractionation of proteins using 2D-PAGE or off-gel fractionation is not necessary. The presented method is therefore easily applicable in analytical routine laboratories without dedicated proteomics background.

NUCLEAR MATERIAL ATTRACTIVENESS: AN ASSESSMENT OF MATERIAL ASSOCIATED WITH A CLOSED FUEL CYCLE

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bathke, C. G.; Ebbinghaus, B.; Sleaford, Brad W.

2010-06-11

This paper examines the attractiveness of materials mixtures containing special nuclear materials (SNM) associated with the various processing steps required for a closed fuel cycle. This paper combines the results from earlier studies that examined the attractiveness of SNM associated with the processing of spent light water reactor (LWR) fuel by various reprocessing schemes and the recycle of plutonium as a mixed oxide (MOX) fuel in LWR with new results for the final, repeated burning of SNM in fast-spectrum reactors: fast reactors and accelerator driven systems (ADS). The results of this paper suggest that all reprocessing products evaluated so farmore » need to be rigorously safeguarded and provided moderate to high levels of physical protection. These studies were performed at the request of the United States Department of Energy (DOE), and are based on the calculation of "attractiveness levels" that has been couched in terms chosen for consistency with those normally used for nuclear materials in DOE nuclear facilities. The methodology and key findings will be presented. Additionally, how these attractiveness levels relate to proliferation resistance (e.g. by increasing impediments to the diversion, theft, or undeclared production of SNM for the purpose of acquiring a nuclear weapon), and how they could be used to help inform policy makers, will be discussed.« less

A Monte Carlo Analysis of Weight Data from UF 6 Cylinder Feed and Withdrawal Stations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Garner, James R; Whitaker, J Michael

2015-01-01

As the number of nuclear facilities handling uranium hexafluoride (UF 6) cylinders (e.g., UF 6 production, enrichment, and fuel fabrication) increase in number and throughput, more automated safeguards measures will likely be needed to enable the International Atomic Energy Agency (IAEA) to achieve its safeguards objectives in a fiscally constrained environment. Monitoring the process data from the load cells built into the cylinder feed and withdrawal (F/W) stations (i.e., cylinder weight data) can significantly increase the IAEA’s ability to efficiently achieve the fundamental safeguards task of confirming operations as declared (i.e., no undeclared activities). Researchers at the Oak Ridge Nationalmore » Laboratory, Los Alamos National Laboratory, the Joint Research Center (in Ispra, Italy), and University of Glasgow are investigating how this weight data can be used for IAEA safeguards purposes while fully protecting the operator’s proprietary and sensitive information related to operations. A key question that must be resolved is, what is the necessary frequency of recording data from the process F/W stations to achieve safeguards objectives? This paper summarizes Monte Carlo simulations of typical feed, product, and tails withdrawal cycles and evaluates longer sampling frequencies to determine the expected errors caused by low-frequency sampling and its impact on material balance calculations.« less

Adulteration of herbal sexual enhancers and slimmers: The wish for better sexual well-being and perfect body can be risky.

PubMed

Skalicka-Woźniak, Krystyna; Georgiev, Milen I; Orhan, Ilkay Erdogan

2017-10-01

The popularity of herbal medicines and dietary supplements is increasing all over the world due to the many side-effects assigned to synthetic drugs. Herbal remedies should be considered as safe, with no side-effects, but unfortunately, even if they are labelled as natural, large numbers of adulterants, not only with toxic heavy metals but also with undeclared synthetic substances, have been detected up to date. In this review, the most frequent instances of adulteration of herbal medicines and dietary supplements acting as sexual enhancers and slimming products are thoroughly discussed. The great success of synthetic phosphodiesterase type-5 (PDE-5) inhibitory drugs like sildenafil, vardenafil and tadalafil, used for the treatment of erectile dysfunction has made them, as well as their unapproved analogues, popular as adulterants in herbal dietary supplements. The second group among blockbuster products are herbal preparations for slimming purpose, as obesity and gaining weight are major problems worldwide. Here, sibutramine hydrochloride monohydrate, an anti-obesity drug which inhibits serotonergic and noradrenergic reuptake, seems to be the most common adulterant. Together with large numbers of its analogues, thyroid hormones, anorexigens, diuretics, stimulants, and laxative agents are also detected in most of tested diet supplements. Copyright © 2016 Elsevier Ltd. All rights reserved.

MALDI-based identification of stable hazelnut protein derived tryptic marker peptides.

PubMed

Cucu, T; De Meulenaer, B; Devreese, B

2012-01-01

Food allergy is an important health problem especially in industrialised countries. Tree nuts, among which are hazelnuts (Corylus avellana), are typically causing serious and life-threatening symptoms in sensitive subjects. Hazelnut is used as a food ingredient in pastry, confectionary products, ice cream and meat products, therefore undeclared hazelnut can be often present as a cross-contaminant representing a threat for allergic consumers. Mass spectrometric techniques are used for the detection of food allergens in processed foods, but limited information regarding stable tryptic peptide markers for hazelnut is available. The aim of this study was to detect stable peptide markers from modified hazelnut protein through the Maillard reaction and oxidation in a buffered solution. Peptides ³⁹⁵Gly-Arg⁴⁰³ from Cor a 11 and ²⁰⁹Gln-Arg²¹⁷, ³⁵¹Ile-Arg³⁶³, ⁴⁶⁴Ala-Arg⁴⁷⁸ and ⁴⁰¹Val-Arg⁴¹⁷ from Cor a 9 hazelnut allergens proved to be the most stable and could be detected and confirmed with high scores in most of the modified samples. The identified peptides can be further used as analytical targets for the development of more robust quantitative methods for hazelnut detection in processed foods.

Poliovirus Polymerase Leu420 Facilitates RNA Recombination and Ribavirin Resistance

PubMed Central

Kempf, Brian J.; Peersen, Olve B.

2016-01-01

ABSTRACT RNA recombination is important in the formation of picornavirus species groups and the ongoing evolution of viruses within species groups. In this study, we examined the structure and function of poliovirus polymerase, 3Dpol, as it relates to RNA recombination. Recombination occurs when nascent RNA products exchange one viral RNA template for another during RNA replication. Because recombination is a natural aspect of picornavirus replication, we hypothesized that some features of 3Dpol may exist, in part, to facilitate RNA recombination. Furthermore, we reasoned that alanine substitution mutations that disrupt 3Dpol-RNA interactions within the polymerase elongation complex might increase and/or decrease the magnitudes of recombination. We found that an L420A mutation in 3Dpol decreased the frequency of RNA recombination, whereas alanine substitutions at other sites in 3Dpol increased the frequency of recombination. The 3Dpol Leu420 side chain interacts with a ribose in the nascent RNA product 3 nucleotides from the active site of the polymerase. Notably, the L420A mutation that reduced recombination also rendered the virus more susceptible to inhibition by ribavirin, coincident with the accumulation of ribavirin-induced G→A and C→U mutations in viral RNA. We conclude that 3Dpol Leu420 is critically important for RNA recombination and that RNA recombination contributes to ribavirin resistance. IMPORTANCE Recombination contributes to the formation of picornavirus species groups and the emergence of circulating vaccine-derived polioviruses (cVDPVs). The recombinant viruses that arise in nature are occasionally more fit than either parental strain, especially when the two partners in recombination are closely related, i.e., members of characteristic species groups, such as enterovirus species groups A to H or rhinovirus species groups A to C. Our study shows that RNA recombination requires conserved features of the viral polymerase. Furthermore, a polymerase mutation that disables recombination renders the virus more susceptible to the antiviral drug ribavirin, suggesting that recombination contributes to ribavirin resistance. Elucidating the molecular mechanisms of RNA replication and recombination may help mankind achieve and maintain poliovirus eradication. PMID:27412593

Pharmacokinetics of intramuscular microparticle depot of valdecoxib in an experimental model.

PubMed

Agnihotri, Sagar M; Vavia, Pradeep R

2009-09-01

We did a prospective study to investigate pharmacokinetics of a single intramuscularly (i.m.) administered Valdecoxib (VC) polymeric microparticles in New Zealand white rabbits. Poly[lac(glc-leu)] microparticles encapsulating a potent cyclooxygenase-2- selective inhibitor, VC, were prepared by emulsion and solvent evaporation technique and administered i.m. to rabbits for pharmacokinetic study. A single i.m. dose of drug-loaded poly[lac(glc-leu)] microparticles resulted in sustained therapeutic drug levels in the plasma for 49 days. The relative bioavailability was increased severalfold as compared with unencapsulated drug. Injectable poly[lac(glc-leu)] microparticles hold promise for increasing drug bioavailability and reducing dosing frequency for better management of rheumatoid arthritis.

The effects of the phyllolitorin analogue [desTrp3,Leu8]phyllolitorin on scratching induced by bombesin and related peptides in rats

PubMed Central

Johnson, Mark D.; Ko, Mei-Chuan; Choo, Kevin S.; Traynor, John R.; Mosberg, Henry I.; Naughton, Norah N.; Woods, James H.

2010-01-01

Bombesin along with several closely related neuropeptides elicit scratching behavior when administered centrally. The first part of the study was designed to determine the antagonistic effects of a novel phyllolitorin analogue wdesTrp3,Leu8]phyllolitorin (DTP) on scratching induced by three peptides (bombesin, neuromedin-C, and [Leu8]phyllolitorin). In addition, the binding affinity of each peptide for the bombesin receptor site was determined. DTP (30 μg) inhibited scratching induced by these peptides, but unlike the peptides, DTP had no affinity for the bombesin site, thereby suggesting that DTP is displaying physiological antagonism through an unknown mechanism. PMID:10482814

Structural analysis of peptides that fill sites near the active center of the two different enzyme molecules by artificial intelligence and computer simulations

NASA Astrophysics Data System (ADS)

Nishiyama, Katsuhiko

2018-05-01

Using artificial intelligence, the binding styles of 167 tetrapeptides were predicted in the active site of papain and cathepsin K. Five tetrapeptides (Asn-Leu-Lys-Trp, Asp-Gln-Trp-Gly, Cys-Gln-Leu-Arg, Gln-Leu-Trp-Thr and Arg-Ser-Glu-Arg) were found to bind sites near the active center of both papain and cathepsin K. These five tetrapeptides have the potential to also bind sites of other cysteine proteases, and structural characteristics of these tetrapeptides should aid the design of a common inhibitor of cysteine proteases. Smart application of artificial intelligence should accelerate data mining of important complex systems.

Auger Spectroscopy Analysis of Spalled LEU-10Mo Foils

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lawrence, Samantha Kay; Schulze, Roland K.

2017-08-03

Presentation includes slides on Surface Science used to probe LEU-10Mo Spall; Auger highlights graphitic-like inclusions and Mo-deficient oxide on base metal; Higher C concentration detected within spall area Images Courtesy; Depth profiling reveals thick oxide; Mo concentration nears nominal only at depths ~400 nm; and lastly Key Findings.

75 FR 4493 - Natural Resources Defense Council; Denial of Petition for Rulemaking

Federal Register 2010, 2011, 2012, 2013, 2014

2010-01-28

... NRC continues to license the civilian use of HEU to fuel seven existing research and test reactors... predicts that the three HEU-fueled TRIGA-type research reactors at Oregon State University, the University...) is scheduled for conversion to LEU but notes that the newer and larger LEU-fueled TRIGA facility at...

Carbon monoxide poisoning is prevented by the energy costs of conformational changes in gas-binding haemproteins.

PubMed

Antonyuk, Svetlana V; Rustage, Neil; Petersen, Christine A; Arnst, Jamie L; Heyes, Derren J; Sharma, Raman; Berry, Neil G; Scrutton, Nigel S; Eady, Robert R; Andrew, Colin R; Hasnain, S Samar

2011-09-20

Carbon monoxide (CO) is a product of haem metabolism and organisms must evolve strategies to prevent endogenous CO poisoning of haemoproteins. We show that energy costs associated with conformational changes play a key role in preventing irreversible CO binding. AxCYTcp is a member of a family of haem proteins that form stable 5c-NO and 6c-CO complexes but do not form O(2) complexes. Structure of the AxCYTcp-CO complex at 1.25 Å resolution shows that CO binds in two conformations moderated by the extent of displacement of the distal residue Leu16 toward the haem 7-propionate. The presence of two CO conformations is confirmed by cryogenic resonance Raman data. The preferred linear Fe-C-O arrangement (170 ± 8°) is accompanied by a flip of the propionate from the distal to proximal face of the haem. In the second conformation, the Fe-C-O unit is bent (158 ± 8°) with no flip of propionate. The energetic cost of the CO-induced Leu-propionate movements is reflected in a 600 mV (57.9 kJ mol(-1)) decrease in haem potential, a value in good agreement with density functional theory calculations. Substitution of Leu by Ala or Gly (structures determined at 1.03 and 1.04 Å resolutions) resulted in a haem site that binds CO in the linear mode only and where no significant change in redox potential is observed. Remarkably, these variants were isolated as ferrous 6c-CO complexes, attributable to the observed eight orders of magnitude increase in affinity for CO, including an approximately 10,000-fold decrease in the rate of dissociation. These new findings have wide implications for preventing CO poisoning of gas-binding haem proteins.

Identification of chemical markers in Cordyceps sinensis by HPLC-MS/MS.

PubMed

Hu, Hankun; Xiao, Ling; Zheng, Baogen; Wei, Xin; Ellis, Alexis; Liu, Yi-Ming

2015-10-01

Authentication and quality assessment of Cordyceps sinensis, a precious and pricey natural product that offers a variety of health benefits, is highly significant. To identify effective chemical markers, authentic C. sinensis was thoroughly screened by using HPLC-MS/MS. In addition to many previously reported ingredients, two glycosides, i.e., cyclo-Ala-Leu-rhamnose and Phe-o-glucose, were detected for the first time in this material. Six ingredients detected, including cordycepin, D-mannitol, Phe, Phe-o-glucose, cyclo-Gly-Pro, and cyclo-Ala-Leu-rhamnose, were selected as a collection of chemical markers. An HPLC-MS/MS method was developed to simultaneously quantify them with sensitivity and specificity. The method had limits of detection ranging from 0.008 μg mL(-1) for cordycepin to 0.75 μg mL(-1) for cyclo-Gly-Pro. Recovery was found between 96 and 103 % in all tests. To evaluate the effectiveness of the marker collection proposed, five authentic C. sinensis samples and five samples of its substitutes were analyzed. Cordycepin, D-mannitol, and Phe were found present in all samples. The contents ranged from 0.0076 to 0.029 % (w/w) for cordycepin, 0.33 to 18.9 % for mannitol, and 0.0013 to 0.642 % for Phe. Interestingly, the two glycosides, Phe-o-glucose and cyclo-Ala-Leu-rhamnose, were detected only in authentic C. sinensis samples. These results indicated that the proposed protocol based on HPLC-MS/MS quantification of the markers might have a great potential in authentication and quality assessment of C. sinensis. Graphical abstract Chemical markers of C. sinensis identified in this work.

Molecular cloning of the pheromone biosynthesis-activating neuropeptide in Helicoverpa zea.

PubMed Central

Davis, M T; Vakharia, V N; Henry, J; Kempe, T G; Raina, A K

1992-01-01

Pheromone biosynthesis-activating neuropeptide (PBAN) regulates sex pheromone biosynthesis in female Helicoverpa (Heliothis) zea. Two oligonucleotide probes representing two overlapping amino acid regions of PBAN were used to screen 2.5 x 10(5) recombinant plaques, and a positive recombinant clone was isolated. Sequence analysis of the isolated clone showed that the PBAN gene is interrupted after the codon encoding amino acid 14 by a 0.63-kilobase (kb) intron. Preceding the PBAN amino acid sequence is a 10-amino acid sequence containing a pentapeptide Phe-Thr-Pro-Arg-Leu, which is followed by a Gly-Arg-Arg processing site. Immediately after the PBAN amino acid sequence is a Gly-Arg processing site and a short stretch of 10 amino acids. This 10-amino acid sequence contains a repeat of the PBAN C-terminal pentapeptide Phe-Ser-Pro-Arg-Leu and is terminated by another Gly-Arg processing site. It is suggested that the PBAN gene in H. zea might carry, besides PBAN, a 7- and an 8-residue amidated peptide, which share with PBAN the core C-terminal pentapeptide Phe-(Ser or Thr)-Pro-Arg-Leu-NH2. The C-terminal pentapeptide sequence of PBAN represents the minimum sequence required for pheromonotropic activity in H. zea and also bears a high degree of homology to the pyrokinin family of insect peptides with myotropic activity. It is possible that the putative heptapeptide and octapeptide might be new members of the pyrokinin family, with pheromonotropic and/or myotropic activities. Thus, the PBAN gene products, besides affecting sexual behavior, might have broad influence on many biological processes in H. zea. Images PMID:1729680

Characterization of Lipopeptide Biosurfactants Produced by Bacillus licheniformis MB01 from Marine Sediments

PubMed Central

Chen, Yulin; Liu, Shiliang A.; Mou, Haijin; Ma, Yunxiao; Li, Meng; Hu, Xiaoke

2017-01-01

Antibiotic resistance has become one of the world’s most severe problems because of the overuse of antibiotics. Antibiotic-resistant bacteria are more difficult to kill and more expensive to treat. Researchers have been studied on antibiotic alternatives such as antimicrobial peptides and lipopeptides. A functional bacteria MB01 producing lipopeptides which can be used as bacteriostat was isolated from the Bohai Sea sediments, which had been identified as Bacillus licheniformis by the morphological, physiological, and biochemical identification and 16s rDNA sequence. The lipopeptides produced by MB01 were determined to be cyclic surfactin homologs by LC-ESI-MS structural identification after crude extraction and LH-20 chromatography. [M+H]+ m/z 994, 1008, 1022, and 1036 were all the characteristic molecular weight of surfactin homologs. CID analysis revealed that the molecular structure of the lipopeptides was Rn-Glu1-Leu/Ile2-Leu3-Val4-Asp5-Leu6-Leu/Ile7. The lipopeptides showed well resistance to UV light and the change of pH and temperature. PMID:28559889

Neutronics Conversion Analyses of the Laue-Langevin Institute (ILL) High Flux Reactor (RHF)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bergeron, A.; Dionne, B.; Calzavara, Y.

2014-09-30

The following report describes the neutronics results obtained with the MCNP model of the RHF U7Mo LEU reference design that has been established in 2010 during the feasibility analysis. This work constitutes a complete and detailed neutronics analysis of that LEU design using models that have been significantly improved since 2010 and the release of the feasibility report. When possible, the credibility of the neutronics model is tested by comparing the HEU model results with experimental data or other codes calculations results. The results obtained with the LEU model are systematically compared to the HEU model. The changes applied tomore » the neutronics model lead to better comparisons with experimental data or improved the calculation efficiency but do not challenge the conclusion of the feasibility analysis. If the U7Mo fuel is commercially available, not cost prohibitive, a back-end solution is established and if it is possible to manufacture the proposed element, neutronics analyses show that the performance of the reactor would not be challenged by the conversion to LEU fuel.« less

Cells adapted to the proteasome inhibitor 4-hydroxy- 5-iodo-3-nitrophenylacetyl-Leu-Leu-leucinal-vinyl sulfone require enzymatically active proteasomes for continued survival.

PubMed

Princiotta, M F; Schubert, U; Chen, W; Bennink, J R; Myung, J; Crews, C M; Yewdell, J W

2001-01-16

The proteasome is the primary protease used by cells for degrading proteins and generating peptide ligands for class I molecules of the major histocompatibility complex. Based on the properties of cells adapted to grow in the presence of the proteasome inhibitor 4-hydroxy-5-iodo-3-nitrophenylacetyl-Leu-Leu-leucinal-vinyl sulfone (NLVS), it was proposed that proteasomes can be replaced by alternative proteolytic systems, particularly a large proteolytic complex with a tripeptidyl peptidase II activity. Here we show that NLVS-adapted cells retain sensitivity to a number of highly specific proteasome inhibitors with regard to antigenic peptide generation, accumulation of polyubiquitinated proteins, degradation of p53, and cell viability. In addition, we show that in the same assays (with a single minor exception), NLVS-adapted cells are about as sensitive as nonselected cells to Ala-Ala-Phe-chloromethylketone, a specific inhibitor of tripeptidyl peptidase II activity. Based on these findings, we conclude that proteasomes still have essential proteolytic functions in adapted cells that are not replaced by Ala-Ala-Phe-chloromethylketone-sensitive proteases.

Activation of IGF-2R stimulates cardiomyocyte hypertrophy in the late gestation sheep fetus

PubMed Central

Wang, Kimberley C W; Brooks, Doug A; Thornburg, Kent L; Morrison, Janna L

2012-01-01

In vitro studies using rat and fetal sheep cardiomyocytes indicate that, in addition to its role as a clearance receptor, the insulin-like growth factor 2 receptor (IGF-2R) can induce cardiomyocyte hypertrophy. In the present study, we have determined the effect of specific activation of the IGF-2R in the heart of the late gestation fetus on cardiomyocyte development. Leu27IGF-2, an IGF-2R agonist, was infused into the fetal left circumflex coronary artery for 4 days beginning at 128.1 ± 0.4 days gestation. Ewes were humanely killed at 132.2 ± 1.2 days gestation (term, 150 days). Fetuses were delivered and hearts dissected to isolate the cardiomyocytes and to collect and snap-freeze tissue. Leu27IGF-2 infusion into the left circumflex coronary artery of fetal sheep increased the area of binucleated cardiomyocytes in the left, but not the right, ventricle. However, this infusion of Leu27IGF-2 did not change fetal weight, heart weight, blood pressure, blood gases or cardiomyocyte proliferation/binucleation. The increase in cardiomyocyte size in the Leu27IGF-2-infused group was associated with increased expression of proteins in the Gαs, but not the Gαq, signalling pathway. We concluded that infusion of Leu27IGF-2 into the left circumflex coronary artery causes cardiac IGF-2R activation in the left ventricle of the heart, and this stimulates cardiomyocyte hypertrophy in a Gαs-dependent manner. PMID:22930271

Effect of herbicide resistance endowing Ile-1781-Leu and Asp-2078-Gly ACCase gene mutations on ACCase kinetics and growth traits in Lolium rigidum.

PubMed

Vila-Aiub, Martin M; Yu, Qin; Han, Heping; Powles, Stephen B

2015-08-01

The rate of herbicide resistance evolution in plants depends on fitness traits endowed by alleles in both the presence and absence (resistance cost) of herbicide selection. The effect of two Lolium rigidum spontaneous homozygous target-site resistance-endowing mutations (Ile-1781-Leu, Asp-2078-Gly) on both ACCase activity and various plant growth traits have been investigated here. Relative growth rate (RGR) and components (net assimilation rate, leaf area ratio), resource allocation to different organs, and growth responses in competition with a wheat crop were assessed. Unlike plants carrying the Ile-1781-Leu resistance mutation, plants homozygous for the Asp-2078-Gly mutation exhibited a significantly lower RGR (30%), which translated into lower allocation of biomass to roots, shoots, and leaves, and poor responses to plant competition. Both the negligible and significant growth reductions associated, respectively, with the Ile-1781-Leu and Asp-2078-Gly resistance mutations correlated with their impact on ACCase activity. Whereas the Ile-1781-Leu mutation showed no pleiotropic effects on ACCase kinetics, the Asp-2078-Gly mutation led to a significant reduction in ACCase activity. The impaired growth traits are discussed in the context of resistance costs and the effects of each resistance allele on ACCase activity. Similar effects of these two particular ACCase mutations on the ACCase activity of Alopecurus myosuroides were also confirmed. © The Author 2015. Published by Oxford University Press on behalf of the Society for Experimental Biology.

Detection of Listeria monocytogenes with short peptide fragments from class IIa bacteriocins as recognition elements.

PubMed

Azmi, Sarfuddin; Jiang, Keren; Stiles, Michael; Thundat, Thomas; Kaur, Kamaljit

2015-03-09

We employed a direct peptide-bacteria binding assay to screen peptide fragments for high and specific binding to Listeria monocytogenes. Peptides were screened from a peptide array library synthesized on cellulose membrane. Twenty four peptide fragments (each a 14-mer) were derived from three potent anti-listerial peptides, Leucocin A, Pediocin PA1, and Curvacin A, that belong to class IIa bacteriocins. Fragment Leu10 (GEAFSAGVHRLANG), derived from the C-terminal region of Leucocin A, displayed the highest binding among all of the library fragments toward several pathogenic Gram-positive bacteria, including L. monocytogenes, Enterococcus faecalis, and Staphylococcus aureus. The specific binding of Leu10 to L. monocytogenes was further validated using microcantilever (MCL) experiments. Microcantilevers coated with gold were functionalized with peptides by chemical conjugation using a cysteamine linker to yield a peptide density of ∼4.8×10(-3) μmol/cm2 for different peptide fragments. Leu10 (14-mer) functionalized MCL was able to detect Listeria with same sensitivity as that of Leucocin A (37-mer) functionalized MCL, validating the use of short peptide fragments in bacterial detection platforms. Fragment Leu10 folded into a helical conformation in solution, like that of native Leucocin A, suggesting that both Leu10 and Leucocin A may employ a similar mechanism for binding target bacteria. The results show that peptide-conjugated microcantilevers can function as highly sensitive platforms for Listeria detection and hold potential to be developed as biosensors for pathogenic bacteria.

Fluorimetric assay of the neurotensin-degrading metalloendopeptidase, endopeptidase 24.16.

PubMed

Dauch, P; Barelli, H; Vincent, J P; Checler, F

1991-12-01

Mcc-Pro-Leu-Gly-Pro-D-Lys-Dnp (Mcc = 3-carboxy-7-methoxycoumarin; Dnp = dinitrophenyl), a quenched fluorimetric substrate originally designed as a probe to measure Pz-peptidase (also called endopeptidase 24.15), was examined as a putative substrate of the neurotensin-degrading neutral metalloendopeptidase, endopeptidase 24.16. During the purification of endopeptidase 24.16 the neurotensin(1-10) and neurotensin(11-13) formation due to this enzyme was coeluted with Mcc-Pro-Leu-Gly-Pro-D-Lys-Dnp-hydrolysing activity. By both fluorimetric and h.p.l.c. analyses, we observed that the latter activity was dose-dependently and completely abolished by neurotensin with an IC50 value (2.6 microM) that closely corresponds to the affinity of purified endopeptidase 24.16 for neurotensin (Km = 2.5 microM). Furthermore, Mcc-Pro-Leu-Gly-Pro-D-Lys-Dnp hydrolysis was inhibited by a series of dipeptides with a rank of order of potencies that parallels that observed in competition experiments of tritiated neurotensin hydrolysis by brain and intestinal endopeptidase 24.16. Altogether, these data clearly demonstrate that, in addition to Pz-peptidase, Mcc-Pro-Leu-Gly-Pro-D-Lys-Dnp also behaves as a substrate of endopeptidase 24.16, with a Km of about 26 microM. In addition, we show that, even in crude membrane preparations, Mcc-Pro-Leu-Gly-Pro-D-Lys-Dnp behaves as a useful tool to monitor and accurately quantify endopeptidase 24.16.

Effect of a novel selective and potent phosphinic peptide inhibitor of endopeptidase 3.4.24.16 on neurotensin-induced analgesia and neuronal inactivation.

PubMed

Vincent, B; Jiracek, J; Noble, F; Loog, M; Roques, B; Dive, V; Vincent, J P; Checler, F

1997-06-01

1. We have examined a series of novel phosphinic peptides as putative potent and selective inhibitors of endopeptidase 3.4.24.16. 2. The most selective inhibitor, Pro-Phe-psi(PO2CH2)-Leu-Pro-NH2 displayed a Ki value of 12 nM towards endopeptidase 3.4.24.16 and was 5540 fold less potent on its related peptidase endopeptidase 3.4.24.15. Furthermore, this inhibitor was 12.5 less potent on angiotensin-converting enzyme and was unable to block endopeptidase 3.4.24.11, aminopeptidases B and M, dipeptidylaminopeptidase IV and proline endopeptidase. 3. The effect of Pro-Phe-psi(PO2CH2)-Leu-Pro-NH2, in vitro and in vivo, on neurotensin metabolism in the central nervous system was examined. 4. Pro-Phe-psi(PO2CHH2)-Leu-Pro-NH2 dose-dependently inhibited the formation of neurotensin 1-10 and concomittantly protected neurotensin from degradation by primary cultured neurones from mouse embryos. 5. Intracerebroventricular administration of Pro-Phe-psi(PO2CH2)-Leu-Pro-NH2 significantly potentiated the neurotensin-induced antinociception of mice in the hot plate test. 6. Altogether, our study has established Pro-Phe-psi(PO2CH2)-Leu-Pro-NH2 as a fully selective and highly potent inhibitor of endopeptidase 3.4.24.16 and demonstrates, for the first time, the contribution of this enzyme in the central metabolism of neurotensin.

Immunohistochemical demonstration of enkephalin-containing nerve fibers in guinea pig and rat lungs.

PubMed

Shimosegawa, T; Foda, H D; Said, S I

1989-08-01

Met-enkephalin (Met-Enk) and Leu-enkephalin (Leu-Enk), the opioid peptides originally isolated from the brain, are believed to act as inhibitory neuromodulators at various synaptic sites. In this immunohistochemical study, we have investigated the localization and distribution of Met- and Leu-Enk immunoreactivities in airways and pulmonary vessels of guinea pigs and rats. Immunoreactivities to both peptides were found in nerve fibers and nerve terminals distributed mainly to the trachea and major bronchi, and were especially prevalent in the smooth muscle layer, in the lamina propria, and around tracheal and bronchial glands, but not in the epithelium. Few immunoreactive nerve fibers were detected in smaller bronchi, bronchioles, and alveoli. Enkephalin-immunoreactive nerve fibers were also localized in the walls of pulmonary and bronchial vessels. Within airway microganglia, immunoreactivity was observed in a few nerve terminals, but not in ganglion cell bodies. Met- and Leu-Enk immunoreactive nerve fibers showed similar distribution patterns, though minor differences were noted between the two species: Enk-immunoreactive nerve fibers in the smooth muscle layer were more abundant in guinea pigs than in rats, whereas those in mucous glands were richer in rats than in guinea pigs. These results document the presence of Met- and Leu-Enk immunoreactivity in nerve fibers supplying guinea pig and rat airways and pulmonary vessels, and provide a morphologic basis for the view that enkephalins are likely neurotransmitters or neuromodulators in the lung.

Effect of a novel selective and potent phosphinic peptide inhibitor of endopeptidase 3.4.24.16 on neurotensin-induced analgesia and neuronal inactivation

PubMed Central

Vincent, Bruno; Jiracek, Jirì; Noble, Florence; Loog, Mart; Roques, Bernard; Dive, Vincent; Vincent, Jean-Pierre; Checler, Frédéric

1997-01-01

We have examined a series of novel phosphinic peptides as putative potent and selective inhibitors of endopeptidase 3.4.24.16. The most selective inhibitor, Pro-Phe-Ψ(PO2CH2)-Leu-Pro-NH2 displayed a Ki value of 12 nM towards endopeptidase 3.4.24.16 and was 5540 fold less potent on its related peptidase endopeptidase 3.4.24.15. Furthermore, this inhibitor was 12.5 less potent on angiotensin-converting enzyme and was unable to block endopeptidase 3.4.24.11, aminopeptidases B and M, dipeptidylaminopeptidase IV and proline endopeptidase. The effect of Pro-Phe-Ψ(PO2CH2)-Leu-Pro-NH2, in vitro and in vivo, on neurotensin metabolism in the central nervous system was examined. Pro-Phe-Ψ(PO2CHH2)-Leu-Pro-NH2 dose-dependently inhibited the formation of neurotensin 1-10 and concomittantly protected neurotensin from degradation by primary cultured neurones from mouse embryos. Intracerebroventricular administration of Pro-Phe-Ψ(PO2CH2)-Leu-Pro-NH2 significantly potentiated the neurotensin-induced antinociception of mice in the hot plate test. Altogether, our study has established Pro-Phe-Ψ(PO2CH2)-Leu-Pro-NH2 as a fully selective and highly potent inhibitor of endopeptidase 3.4.24.16 and demonstrates, for the first time, the contribution of this enzyme in the central metabolism of neurotensin. PMID:9208137

Fluorimetric assay of the neurotensin-degrading metalloendopeptidase, endopeptidase 24.16.

PubMed Central

Dauch, P; Barelli, H; Vincent, J P; Checler, F

1991-01-01

Mcc-Pro-Leu-Gly-Pro-D-Lys-Dnp (Mcc = 3-carboxy-7-methoxycoumarin; Dnp = dinitrophenyl), a quenched fluorimetric substrate originally designed as a probe to measure Pz-peptidase (also called endopeptidase 24.15), was examined as a putative substrate of the neurotensin-degrading neutral metalloendopeptidase, endopeptidase 24.16. During the purification of endopeptidase 24.16 the neurotensin(1-10) and neurotensin(11-13) formation due to this enzyme was coeluted with Mcc-Pro-Leu-Gly-Pro-D-Lys-Dnp-hydrolysing activity. By both fluorimetric and h.p.l.c. analyses, we observed that the latter activity was dose-dependently and completely abolished by neurotensin with an IC50 value (2.6 microM) that closely corresponds to the affinity of purified endopeptidase 24.16 for neurotensin (Km = 2.5 microM). Furthermore, Mcc-Pro-Leu-Gly-Pro-D-Lys-Dnp hydrolysis was inhibited by a series of dipeptides with a rank of order of potencies that parallels that observed in competition experiments of tritiated neurotensin hydrolysis by brain and intestinal endopeptidase 24.16. Altogether, these data clearly demonstrate that, in addition to Pz-peptidase, Mcc-Pro-Leu-Gly-Pro-D-Lys-Dnp also behaves as a substrate of endopeptidase 24.16, with a Km of about 26 microM. In addition, we show that, even in crude membrane preparations, Mcc-Pro-Leu-Gly-Pro-D-Lys-Dnp behaves as a useful tool to monitor and accurately quantify endopeptidase 24.16. PMID:1747117

Erythrocyte selenium concentration predicts intensive care unit and hospital mortality in patients with septic shock: a prospective observational study

PubMed Central

2014-01-01

Introduction Selenoenzymes can modulate the extent of oxidative stress, which is recognized as a key feature of septic shock. The pathophysiologic role of erythrocyte selenium concentration in patients with septic shock remains unknown. Therefore, the objective of this study was to evaluate the association of erythrocyte selenium concentration with glutathione peroxidase (GPx1) activity, GPx1 polymorphisms and with ICU and hospital mortality in septic shock patients. Methods This prospective study included all patients older than 18 years with septic shock on admission or during their ICU stay, admitted to one of the three ICUs of our institution, from January to August 2012. At the time of the patients’ enrollment, demographic information was recorded. Blood samples were taken within the first 72 hours of the patients’ admission or within 72 hours of the septic shock diagnosis for determination of selenium status, protein carbonyl concentration, GPx1 activity and GPx1 Pro198Leu polymorphism (rs 1050450) genotyping. Results A total of 110 consecutive patients were evaluated. The mean age was 57.6 ± 15.9 years, 63.6% were male. Regarding selenium status, only erythrocyte selenium concentration was lower in patients who died in the ICU. The frequencies for GPx1 Pro198Leu polymorphism were 55%, 38% and 7% for Pro/Pro, Pro/Leu and Leu/Leu, respectively. In the logistic regression models, erythrocyte selenium concentration was associated with ICU and hospital mortality in patients with septic shock even after adjustment for protein carbonyl concentration and acute physiology and chronic health evaluation II score (APACHE II) or sequential organ failure assessment (SOFA). Conclusions Erythrocyte selenium concentration was a predictor of ICU and hospital mortality in patients with septic shock. However, this effect was not due to GPx1 activity or Pro198Leu polymorphism. PMID:24887198

Development of potent anti-infective agents from Silurana tropicalis: conformational analysis of the amphipathic, alpha-helical antimicrobial peptide XT-7 and its non-haemolytic analogue [G4K]XT-7.

PubMed

Subasinghage, Anusha P; Conlon, J Michael; Hewage, Chandralal M

2010-04-01

Peptide XT-7 (GLLGP(5)LLKIA(10)AKVGS(15)NLL.NH(2)) is a cationic, leucine-rich peptide, first isolated from skin secretions of the frog, Silurana tropicalis (Pipidae). The peptide shows potent, broad-spectrum antimicrobial activity but its therapeutic potential is limited by haemolytic activity (LC(50)=140 microM). The analogue [G4K]XT-7, however, retains potent antimicrobial activity but is non-haemolytic (LC(50)>500 microM). In order to elucidate the molecular basis for this difference in properties, the three dimensional structures of XT-7 and the analogue have been investigated by proton NMR spectroscopy and molecular modelling. In aqueous solution, both peptides lack secondary structure. In a 2,2,2-trifluoroethanol (TFE-d(3))-H(2)O mixed solvent system, XT-7 is characterised by a right handed alpha-helical conformation between residues Leu(3) and Leu(17) whereas [G4K]XT-7 adopts a more restricted alpha-helical conformation between residues Leu(6) and Leu(17). A similar conformation for XT-7 in 1,2-dihexanoyl-sn-glycero-3-phosphocholine (DHPC) micellular media was observed with a helical segment between Leu(3) and Leu(17). However, differences in side chain orientations restricting the hydrophilic residues to a smaller patch resulted in an increased hydrophobic surface relative to the conformation in TFE-H(2)O. Molecular modelling of the structures obtained in our study demonstrates the amphipathic character of the helical segments. It is proposed that the marked decrease in haemolytic activity produced by the substitution Gly(4)-->Lys in XT-7 arises from a decrease in both helicity and hydrophobicity. These studies may facilitate the development of potent but non-toxic anti-infective agents based upon the structure of XT-7. Copyright 2009 Elsevier B.V. All rights reserved.

Analysis of common transforming growth factor beta-1 gene polymorphisms in gastric and duodenal ulcer disease: pilot study.

PubMed

Polonikov, Alexey V; Ivanov, Vladimir P; Belugin, Dmitry A; Khoroshaya, Irina V; Kolchanova, Inessa O; Solodilova, Mariya A; Tutochkina, Margarita P; Stepchenko, Alexander A

2007-04-01

Transforming growth factor-beta1 (TGF-beta1) has been shown to be an important cytokine that plays a role in cell proliferation, differentiation, tissue injury repair and ulcer healing. The purpose of this pilot study was to investigate if common polymorphisms Leu10Pro, Arg25Pro and C-509T within the TGF-beta1 gene are associated with susceptibility to gastric and duodenal ulcer disease in Russians. Blood samples from 377 unrelated patients with gastric and duodenal ulcer disease and 226 sex- and age-matched healthy controls were used to determine TGF-beta1 gene polymorphisms by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). Leu10Pro substitution in the signal peptide of TGF-beta1 has been found to be associated with susceptibility to gastric ulcer (odds ratio [OR] 1.76, 95% confidence interval [CI] 1.12-2.77). A genotype combination of 10Leu/Leu x 25Arg/Arg x -509C/C was also associated with susceptibility to gastric ulcer disease (OR 1.81, P = 0.01). In addition, the frequency of a combination of genotypes 10Pro/Pro x 25Arg/Pro x -509C/T was statistically lower in patients with duodenal ulcer than in controls (OR 0.42, P = 0.05). A significant difference (P = 0.04) in the distribution of rare haplotypes of the TGF-beta1 gene between patients with duodenal ulcer and healthy controls has been found. Polymorphism Leu10Pro was in positive linkage disequilibrium with C-509T polymorphism (coefficient D = 0.191; P < 0.0001). These findings indicate that the Leu10Pro and C-509T polymorphisms may be involved in the modulation of expression of the TGF-beta1 gene, and therefore a predisposition to peptic ulcer disease could be linked to particular alleles of this gene. In particular, a possible role of TGF-beta1 in the pathogenesis of gastric ulcer disease is discussed.

GLUTATHIONE PEROXIDASE-1 PRO200LEU POLYMORPHISM (RS1050450) IS ASSOCIATED WITH MORBID OBESITY INDEPENDENTLY OF THE PRESENCE OF PREDIABETES OR DIABETES IN WOMEN FROM CENTRAL MEXICO.

PubMed

Hernández Guerrero, César; Hernández Chávez, Paulina; Martínez Castro, Noemí; Parra Carriedo, Alicia; García Del Rio, Sandra; Pérez Lizaur, Ana

2015-10-01

obesity affects more than a third of Mexican population. Oxidative stress participates actively in the etiology of this phenomenon. Glutathione peroxidase-1 (GPX-1) plays a protective role against oxidative stress. The SNP Pro200Leu (rs10504050) has been reported to affect the activity of the enzyme. to determine the frequency of rs10504050 polymorphism in women with obesity and normal weight control, asses the concentration of peripheral TBARS and evaluate the consumption of pro and antioxidants. 104 women with obesity and 70 healthy controls (CG) were included in the study. Anthropometric, biochemical, clinical and dietary features were evaluated. GPx-1 rs10504050 was determined by PCR/RFLP method. TBARS was assayed spectrophotometrically in plasma. The subjects were stratified and compared by obesity grades and by subgroups of prediabetes and diabetes condition. Statistical analysis included ANOVA of Kruskal Wallis, Xi squared and Pearson correlation. for rs10504050 polymorphism there were differences (Xi2 = 6; p = 0.01) between frequency (0.61) of obese carriers (Pro/Leu plus Leu/Leu) and CG carriers (0.42), and between (Xi2 = 8; p = 0.004) morbid (IMC > 40) obesity (0.74) and CG carriers. The obese group (OB) showed a prevalence of 66% of prediabetes plus diabetes. There were no differences in frequencies of rs10504050 in OB with pre or diabetes versus CG, or versus obese participants without diabetes. TBARS concentration was greater in all the degrees of OB versus CG. GPx-1 Pro200Leu polymorphism was associated with obesity especially with morbid obesity, but not with obese participants with prediabetes or diabetes. Oxidative stress is present in all grades of obesity significantly. Copyright AULA MEDICA EDICIONES 2014. Published by AULA MEDICA. All rights reserved.

The p.Leu167del Mutation in APOE Gene Causes Autosomal Dominant Hypercholesterolemia by Down-regulation of LDL Receptor Expression in Hepatocytes.

PubMed

Cenarro, Ana; Etxebarria, Aitor; de Castro-Orós, Isabel; Stef, Marianne; Bea, Ana M; Palacios, Lourdes; Mateo-Gallego, Rocío; Benito-Vicente, Asier; Ostolaza, Helena; Tejedor, Teresa; Martín, César; Civeira, Fernando

2016-05-01

The p.Leu167del mutation in the APOE gene has been associated with hyperlipidemia. Our objective was to determine the frequency of p.Leu167del mutation in APOE gene in subjects with autosomal dominant hypercholesterolemia (ADH) in whom LDLR, APOB, and PCSK9 mutations had been excluded and to identify the mechanisms by which this mutant apo E causes hypercholesterolemia. The APOE gene was analyzed in a case-control study. The study was conducted at a University Hospital Lipid Clinic. Two groups (ADH, 288 patients; control, 220 normolipidemic subjects) were included. We performed sequencing of APOE gene and proteomic and cellular experiments. To determine the frequency of the p.Leu167del mutation and the mechanism by which it causes hypercholesterolemia. In the ADH group, nine subjects (3.1%) were carriers of the APOE c.500_502delTCC, p.Leu167del mutation, cosegregating with hypercholesterolemia in studied families. Proteomic quantification of wild-type and mutant apo E in very low-density lipoprotein (VLDL) from carrier subjects revealed that apo E3 is almost a 5-fold increase compared to mutant apo E. Cultured cell studies revealed that VLDL from mutation carriers had a significantly higher uptake by HepG2 and THP-1 cells compared to VLDL from subjects with E3/E3 or E2/E2 genotypes. Transcriptional down-regulation of LDLR was also confirmed. p.Leu167del mutation in APOE gene is the cause of hypercholesterolemia in the 3.1% of our ADH subjects without LDLR, APOB, and PCSK9 mutations. The mechanism by which this mutation is associated to ADH is that VLDL carrying the mutant apo E produces LDLR down-regulation, thereby raising plasma low-density lipoprotein cholesterol levels.

Development and validation of a rapid test system for detection of pork meat and collagen residues.

PubMed

Masiri, J; Benoit, L; Barrios-Lopez, B; Thienes, C; Meshgi, M; Agapov, A; Dobritsa, A; Nadala, C; Samadpour, M

2016-11-01

Mislabeling, contamination, and economic adulteration of meat products with undeclared pork tissues are illegal under regulations promulgated by numerous regulatory agencies. Nonetheless, analysis of the European meat industry has revealed pervasive meat adulteration, necessitating more extensive application of meat authentication testing. As existing methods for meat speciation require specialized equipment and/or training, we developed a detection system based on a lateral flow device (LFD) assay format capable of rapidly (~35min) identifying porcine residues derived from raw meat, cooked meat, and gelatin down to 0.01%, 1.0%, and 2.5% contamination, respectively. Specificity analysis revealed no cross-reactivity with meat derived from chicken, turkey, horse, beef, lamb, or goat. Comparison with a commercial ELISA kit and PCR method revealed similar if not improved sensitivity, with the added feature that the LFD-based system required considerably less time to perform. Accordingly, this test system should aid the food industry and food control authorities in monitoring for adulteration with pork. Copyright © 2016 Elsevier Ltd. All rights reserved.

Leucine partially protects muscle mass and function during bed rest in middle-aged adults1,2

PubMed Central

English, Kirk L; Mettler, Joni A; Ellison, Jennifer B; Mamerow, Madonna M; Arentson-Lantz, Emily; Pattarini, James M; Ploutz-Snyder, Robert; Sheffield-Moore, Melinda; Paddon-Jones, Douglas

2016-01-01

Background: Physical inactivity triggers a rapid loss of muscle mass and function in older adults. Middle-aged adults show few phenotypic signs of aging yet may be more susceptible to inactivity than younger adults. Objective: The aim was to determine whether leucine, a stimulator of translation initiation and skeletal muscle protein synthesis (MPS), can protect skeletal muscle health during bed rest. Design: We used a randomized, double-blind, placebo-controlled trial to assess changes in skeletal MPS, cellular signaling, body composition, and skeletal muscle function in middle-aged adults (n = 19; age ± SEM: 52 ± 1 y) in response to leucine supplementation (LEU group: 0.06 g ∙ kg−1 ∙ meal−1) or an alanine control (CON group) during 14 d of bed rest. Results: Bed rest decreased postabsorptive MPS by 30% ± 9% (CON group) and by 10% ± 10% (LEU group) (main effect for time, P < 0.05), but no differences between groups with respect to pre-post changes (group × time interactions) were detected for MPS or cell signaling. Leucine protected knee extensor peak torque (CON compared with LEU group: −15% ± 2% and −7% ± 3%; group × time interaction, P < 0.05) and endurance (CON compared with LEU: −14% ± 3% and −2% ± 4%; group × time interaction, P < 0.05), prevented an increase in body fat percentage (group × time interaction, P < 0.05), and reduced whole-body lean mass loss after 7 d (CON compared with LEU: −1.5 ± 0.3 and −0.8 ± 0.3 kg; group × time interaction, P < 0.05) but not 14 d (CON compared with LEU: −1.5 ± 0.3 and −1.0 ± 0.3 kg) of bed rest. Leucine also maintained muscle quality (peak torque/kg leg lean mass) after 14 d of bed-rest inactivity (CON compared with LEU: −9% ± 2% and +1% ± 3%; group × time interaction, P < 0.05). Conclusions: Bed rest has a profoundly negative effect on muscle metabolism, mass, and function in middle-aged adults. Leucine supplementation may partially protect muscle health during relatively brief periods of physical inactivity. This trial was registered at clinicaltrials.gov as NCT00968344. PMID:26718415

Effects of GRK5 and ADRB1 polymorphisms influence on systolic heart failure.

PubMed

Kang, Sheng; Hong, Xuan; Ruan, Chang-wu; Yu, Ping; Yu, Shan-shan; Chen, Ming; Zhang, Dai-fu; Fan, Hui-min; Liu, Zhong-min

2015-02-01

G-protein receptor kinase 5 (GRK5) Gln41 > Leu and β1-adrenergic receptor (ADRB1) Arg389 > Gly polymorphisms presented the different distribution of genotype frequencies between Caucasian American and African American, and produced the difference in β-blocker treatment effect among them with systolic heart failure (SHF). This study sought to identify the distributed characteristics of these variant genotypes in Chinese population, and influence of GRK5 and ADRB1 polymorphisms on SHF morbidity and β-blocker treatment effect in patients with SHF. This study was based on cross-sectional survey data. 1794 and 1718 subjects' ADRB1 and GRK5 gene sequencing (sanger method) data were achieved respectively. Blood samples collection, clinical laboratory detection, electrocardiogram and echocardiography examinations were performed. Medication usage was confirmed at in-hospital visits or the questionnaire by personal interview. GRK5 Leu41Leu genotype was not found in our Chinese population. In non-SHF population, allele frequencies of GRK5 Gln41 and Leu41 were 2782 (0.992) and 22 (0.008) (Hardy-Weinberg equilibrium test χ(2) = 0.088, P = 0.767), and allele frequencies of ADRB1 Arg389 and Gly389 were 2127 (0.715) and 849 (0.285) (χ(2) = 0.272, P = 0.602). In SHF patients, allele frequencies of Gln41 and Leu41 were 446 (0.991) and 4 (0.009) (χ(2) = 0.018, P = 0.893), and allele frequencies of Arg389 and Gly389 were 331 (0.726) and 125 (0.274) (χ(2) = 1.892, P = 0.169). Further in logistic regression model, these ADRB1 and GRK5 variants were not significantly independently associated with the risk of SHF morbidity. Those carrying genotype ADRB1 Gly389Gly did not reduce significantly the risk of SHF morbidity after β-blocker therapy. GRK5 Leu41Leu genotype was not found in our Chinese population, neither ADRB1 nor GRK5 variants presented independently associated with the risk of SHF morbidity, most ADRB1 and GRK5 polymorphisms did decrease significantly the risk of SHF morbidity after β-blocker therapy except for those carrying genotype ADRB1 Gly389Gly.

Rapamycin blocks leucine-induced protein synthesis by suppressing mTORC1 activation in skeletal muscle of neonatal pigs

USDA-ARS?s Scientific Manuscript database

Skeletal muscle in the neonate grows at a rapid rate due in part to an enhanced sensitivity to the postprandial rise in amino acids, particularly leucine (Leu). To elucidate the molecular mechanism by which Leu stimulates protein synthesis in neonatal muscle, overnight fasted 7-day-old piglets were...

Influence of uncertainties of isotopic composition of the reprocessed uranium on effectiveness of its enrichment in gas centrifuge cascades

NASA Astrophysics Data System (ADS)

Smirnov, A. Yu; Mustafin, A. R.; Nevinitsa, V. A.; Sulaberidze, G. A.; Dudnikov, A. A.; Gusev, V. E.

2017-01-01

The effect of the uncertainties of the isotopic composition of the reprocessed uranium on its enrichment process in gas centrifuge cascades while diluting it by adding low-enriched uranium (LEU) and waste uranium. It is shown that changing the content of 232U and 236U isotopes in the initial reprocessed uranium within 15% (rel.) can significantly change natural uranium consumption and separative work (up to 2-3%). However, even in case of increase of these parameters is possible to find the ratio of diluents, where the cascade with three feed flows (depleted uranium, LEU and reprocessed uranium) will be more effective than ordinary separation cascade with one feed point for producing LEU from natural uranium.

Leucine-enkephalin-like immunoreactivity is localized in luteinizing hormone-producing cells in the axolotl (Ambystoma mexicanum) pituitary.

PubMed

Suzuki, Hirohumi; Yamamoto, Toshiharu

2014-02-01

In this study, we used immunohistochemical techniques to determine the cell type of leucine-enkephalin (Leu-ENK)-immunoreactive cells in the axolotl (Ambystoma mexicanum) pituitary. Immunoreactive cells were scattered throughout the pars distalis except for the dorso-caudal portion. These cells were immuno-positive for luteinizing hormone (LH), but they were immuno-negative for adrenocorticotrophic, growth, and thyroid-stimulating hormones, as well as prolactin. Immunoelectron microscopy demonstrated that Leu-ENK-like substance and LH co-localized within the same secretory granules. Leu-ENK secreted from gonadotrophs may participate in LH secretion in an autocrine fashion, and/or may participate in the release of sex steroids together with LH. Copyright © 2013 Elsevier Ltd. All rights reserved.

Integration of the ubiquitin-proteasome pathway with a cytosolic oligopeptidase activity

PubMed Central

Wang, Evelyn W.; Kessler, Benedikt M.; Borodovsky, Anna; Cravatt, Benjamin F.; Bogyo, Matthew; Ploegh, Hidde L.; Glas, Rickard

2000-01-01

Cytosolic proteolysis is carried out predominantly by the proteasome. We show that a large oligopeptidase, tripeptidylpeptidase II (TPPII), can compensate for compromised proteasome activity. Overexpression of TPPII is sufficient to prevent accumulation of polyubiquitinated proteins and allows survival of EL-4 cells at otherwise lethal concentrations of the covalent proteasome inhibitor NLVS (NIP-leu-leu-leu-vinylsulfone). Elevated TPPII activity also partially restores peptide loading of MHC molecules. Purified proteasomes from adapted cells lack the chymotryptic-like activity, but still degrade longer peptide substrates via residual activity of their Z subunits. However, growth of adapted cells depends on induction of other proteolytic activities. Therefore, cytosolic oligopeptidases such as TPPII normalize rates of intracellular protein breakdown required for normal cellular function and viability. PMID:10954757

DOE Office of Scientific and Technical Information (OSTI.GOV)

Carla Miller; Mary Adamic; Stacey Barker

Traditionally, IAEA inspectors have focused on the detection of nuclear indicators as part of infield inspection activities. The ability to rapidly detect and identify chemical as well as nuclear signatures can increase the ability of IAEA inspectors to detect undeclared activities at a site. Identification of chemical indicators have been limited to use in the analysis of environmental samples. Although IAEA analytical laboratories are highly effective, environmental sample processing does not allow for immediate or real-time results to an IAEA inspector at a facility. During a complementary access inspection, under the Additional Protocol, the use of fieldable technologies that canmore » quickly provide accurate information on chemicals that may be indicative of undeclared activities can increase the ability of IAEA to effectively and efficiently complete their mission. The Complementary Access Working Group (CAWG) is a multi-laboratory team with members from Brookhaven National Laboratory, Idaho National Laboratory, Los Alamos National Laboratory, and Sandia National Laboratory. The team identified chemicals at each stage of the nuclear fuel cycle that may provide IAEA inspectors with indications that proliferation activities may be occurring. The group eliminated all indicators related to equipment, technology and training, developing a list of by-products/effluents, non-nuclear materials, nuclear materials, and other observables. These proliferation indicators were prioritized based on detectability from a conduct of operations (CONOPS) perspective of a CA inspection (for example, whether an inspector actually can access the S&O or whether it is in process with no physical access), and the IAEA’s interest in the detection technology in conjunction with radiation detectors. The list was consolidated to general categories (nuclear materials from a chemical detection technique, inorganic chemicals, organic chemicals, halogens, and miscellaneous materials). The team then identified commercial off the shelf (COTS) chemical detectors that may detect the chemicals of interest. Three chemical detectors were selected and tested both in laboratory settings and in field operations settings at Idaho National Laboratory. The instruments selected are: Thermo Scientific TruDefender FT (FTIR), Thermo Scientific FirstDefender RM (Raman), and Bruker Tracer III SD (XRF). Functional specifications, operability, and chemical detectability, selectivity, and limits of detection were determined. Results from the laboratory and field tests will be presented. This work is supported by the Next Generation Safeguards Initiative, Office of Nonproliferation and International Security, National Nuclear Security Administration.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Youker, Amanda J.; Krebs, John F.; Quigley, Kevin J.

With funding from the National Nuclear Security Administrations Material Management and Minimization Office, Argonne National Laboratory (Argonne) is providing technical assistance to help accelerate the U.S. production of Mo-99 using a non-highly enriched uranium (non-HEU) source. A potential Mo-99 production pathway is by accelerator-initiated fissioning in a subcritical uranyl sulfate solution containing low enriched uranium (LEU). As part of the Argonne development effort, we are undertaking the AMORE (Argonne Molybdenum Research Experiment) project, which is essentially a pilot facility for all phases of Mo-99 production, recovery, and purification. Production of Mo-99 and other fission products in the subcritical target solutionmore » is initiated by putting an electron beam on a depleted uranium (DU) target; the fast neutrons produced in the DU target are thermalized and lead to fissioning of U-235. At the end of irradiation, Mo is recovered from the target solution and separated from uranium and most of the fission products by using a titania column. The Mo is stripped from the column with an alkaline solution. After acidification of the Mo product solution from the recovery column, the Mo is concentrated (and further purified) in a second titania column. The strip solution from the concentration column is then purified with the LEU Modified Cintichem process. A full description of the process can be found elsewhere [1–3]. The initial commissioning steps for the AMORE project include performing a Mo-99 spike test with pH 1 sulfuric acid in the target vessel without a beam on the target to demonstrate the initial Mo separation-and-recovery process, followed by the concentration column process. All glovebox operations were tested with cold solutions prior to performing the Mo-99 spike tests. Two Mo-99 spike tests with pH 1 sulfuric acid have been performed to date. Figure 1 shows the flow diagram for the remotely operated Mo-recovery system for the AMORE project. There are two separate pumps and flow paths for the acid and base operations. The system contains three sample ladders with eight sample loops per ladder for target mixing; column loading, including acid and water washes; and column stripping, including the final water wash.« less

Purification and characterization of a surfactin-like molecule produced by Bacillus sp. H2O-1 and its antagonistic effect against sulfate reducing bacteria

PubMed Central

2012-01-01

Background Bacillus sp. H2O-1, isolated from the connate water of a Brazilian reservoir, produces an antimicrobial substance (denoted as AMS H2O-1) that is active against sulfate reducing bacteria, which are the major bacterial group responsible for biogenic souring and biocorrosion in petroleum reservoirs. Thus, the use of AMS H2O-1 for sulfate reducing bacteria control in the petroleum industry is a promising alternative to chemical biocides. However, prior to the large-scale production of AMS H2O-1 for industrial applications, its chemical structure must be elucidated. This study also analyzed the changes in the wetting properties of different surfaces conditioned with AMS H2O-1 and demonstrated the effect of AMS H2O-1 on sulfate reducing bacteria cells. Results A lipopeptide mixture from AMS H2O-1 was partially purified on a silica gel column and identified via mass spectrometry (ESI-MS). It comprises four major components that range in size from 1007 to 1049 Da. The lipid moiety contains linear and branched β-hydroxy fatty acids that range in length from C13 to C16. The peptide moiety contains seven amino acids identified as Glu-Leu-Leu-Val-Asp-Leu-Leu. Transmission electron microscopy revealed cell membrane alteration of sulfate reducing bacteria after AMS H2O-1 treatment at the minimum inhibitory concentration (5 μg/ml). Cytoplasmic electron dense inclusions were observed in treated cells but not in untreated cells. AMS H2O-1 enhanced the osmosis of sulfate reducing bacteria cells and caused the leakage of the intracellular contents. In addition, contact angle measurements indicated that different surfaces conditioned by AMS H2O-1 were less hydrophobic and more electron-donor than untreated surfaces. Conclusion AMS H2O-1 is a mixture of four surfactin-like homologues, and its biocidal activity and surfactant properties suggest that this compound may be a good candidate for sulfate reducing bacteria control. Thus, it is a potential alternative to the chemical biocides or surface coating agents currently used to prevent SRB growth in petroleum industries. PMID:23131170

Data Compilation for AGR-3/4 Designed-to-Fail (DTF) Fuel Particle Batch LEU04-02DTF

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hunn, John D; Miller, James Henry

2008-10-01

This document is a compilation of coating and characterization data for the AGR-3/4 designed-to-fail (DTF) particles. The DTF coating is a high density, high anisotropy pyrocarbon coating of nominal 20 {micro}m thickness that is deposited directly on the kernel. The purpose of this coating is to fail early in the irradiation, resulting in a controlled release of fission products which can be analyzed to provide data on fission product transport. A small number of DTF particles will be included with standard TRISO driver fuel particles in the AGR-3 and AGR-4 compacts. The ORNL Coated Particle Fuel Development Laboratory 50-mm diametermore » fluidized bed coater was used to coat the DTF particles. The coatings were produced using procedures and process parameters that were developed in an earlier phase of the project as documented in 'Summary Report on the Development of Procedures for the Fabrication of AGR-3/4 Design-to-Fail Particles', ORNL/TM-2008/161. Two coating runs were conducted using the approved coating parameters. NUCO425-06DTF was a final process qualification batch using natural enrichment uranium carbide/uranium oxide (UCO) kernels. After the qualification run, LEU04-02DTF was produced using low enriched UCO kernels. Both runs were inspected and determined to meet the specifications for DTF particles in section 5 of the AGR-3 & 4 Fuel Product Specification (EDF-6638, Rev.1). Table 1 provides a summary of key properties of the DTF layer. For comparison purposes, an archive sample of DTF particles produced by General Atomics was characterized using identical methods. This data is also summarized in Table 1.« less

A role for nuclear translocation of tripeptidyl-peptidase II in reactive oxygen species-dependent DNA damage responses

DOE Office of Scientific and Technical Information (OSTI.GOV)

Preta, Giulio; Klark, Rainier de; Glas, Rickard, E-mail: rickard.glas@ki.se

2009-11-27

Responses to DNA damage are influenced by cellular metabolism through the continuous production of reactive oxygen species (ROS), of which most are by-products of mitochondrial respiration. ROS have a strong influence on signaling pathways during responses to DNA damage, by relatively unclear mechanisms. Previous reports have shown conflicting data on a possible role for tripeptidyl-peptidase II (TPPII), a large cytosolic peptidase, within the DNA damage response. Here we show that TPPII translocated into the nucleus in a p160-ROCK-dependent fashion in response to {gamma}-irradiation, and that nuclear expression of TPPII was present in most {gamma}-irradiated transformed cell lines. We used amore » panel of nine cell lines of diverse tissue origin, including four lymphoma cell lines (T, B and Hodgkins lymphoma), a melanoma, a sarcoma, a colon and two breast carcinomas, where seven out of nine cell lines showed nuclear TPPII expression after {gamma}-irradiation. Further, this required cellular production of ROS; treatment with either N-acetyl-Cysteine (anti-oxidant) or Rotenone (inhibitor of mitochondrial respiration) inhibited nuclear accumulation of TPPII. The local density of cells was important for nuclear accumulation of TPPII at early time-points following {gamma}-irradiation (at 1-4 h), indicating a bystander effect. Further, we showed that the peptide-based inhibitor Z-Gly-Leu-Ala-OH, but not its analogue Z-Gly-(D)-Leu-Ala-OH, excluded TPPII from the nucleus. This correlated with reduced nuclear expression of p53 as well as caspase-3 and -9 activation in {gamma}-irradiated lymphoma cells. Our data suggest a role for TPPII in ROS-dependent DNA damage responses, through alteration of its localization from the cytosol into the nucleus.« less

A role for nuclear translocation of tripeptidyl-peptidase II in reactive oxygen species-dependent DNA damage responses.

PubMed

Preta, Giulio; de Klark, Rainier; Glas, Rickard

2009-11-27

Responses to DNA damage are influenced by cellular metabolism through the continuous production of reactive oxygen species (ROS), of which most are by-products of mitochondrial respiration. ROS have a strong influence on signaling pathways during responses to DNA damage, by relatively unclear mechanisms. Previous reports have shown conflicting data on a possible role for tripeptidyl-peptidase II (TPPII), a large cytosolic peptidase, within the DNA damage response. Here we show that TPPII translocated into the nucleus in a p160-ROCK-dependent fashion in response to gamma-irradiation, and that nuclear expression of TPPII was present in most gamma-irradiated transformed cell lines. We used a panel of nine cell lines of diverse tissue origin, including four lymphoma cell lines (T, B and Hodgkins lymphoma), a melanoma, a sarcoma, a colon and two breast carcinomas, where seven out of nine cell lines showed nuclear TPPII expression after gamma-irradiation. Further, this required cellular production of ROS; treatment with either N-acetyl-Cysteine (anti-oxidant) or Rotenone (inhibitor of mitochondrial respiration) inhibited nuclear accumulation of TPPII. The local density of cells was important for nuclear accumulation of TPPII at early time-points following gamma-irradiation (at 1-4h), indicating a bystander effect. Further, we showed that the peptide-based inhibitor Z-Gly-Leu-Ala-OH, but not its analogue Z-Gly-(D)-Leu-Ala-OH, excluded TPPII from the nucleus. This correlated with reduced nuclear expression of p53 as well as caspase-3 and -9 activation in gamma-irradiated lymphoma cells. Our data suggest a role for TPPII in ROS-dependent DNA damage responses, through alteration of its localization from the cytosol into the nucleus.

Pharmacoinformatics approach for the identification of Polo-like kinase-1 inhibitors from natural sources as anti-cancer agents.

PubMed

AlAjmi, Mohamed F; Rehman, Md Tabish; Hussain, Afzal; Rather, Gulam Mohmad

2018-05-05

Polo-like kinase-1 (PLK-1) plays a key role in cell cycle progression during mitosis. Overexpression/dysfunction of PLK-1 is directly associated with cancerous transformation and has been reported in different cancer types. Here, we employed high throughput virtual screening and molecular docking to screen Selleck's natural compound library against PLK-1 kinase domain. We have identified eight bioactive compounds (Apigenin, Dihydromyricetin, Diosmetin, Hesperidin, Hesperitin, Naringenin, Phlorizi, and Quercetin) as the potential inhibitors of PLK-1. Further investigation through Molecular Mechanics-Generalized Born Surface Area (MM-GBSA) calculations and 15 ns molecular dynamics simulation revealed that hesperidin formed the most stable complex with PLK-1 kinase domain. Altogether, our results indicate that hesperidin interacted strongly with the key residues of the PLK-1 active site (such as Leu59, Lys61, Lys82, Cys133, Asn181, Asp194, Leu59, Cys67, Ala80, Val114, Leu130, Leu132, Cys133, Leu139, Phe183, and Phe195) through hydrogen bonding and hydrophobic interactions. The Hesperidin-PLK-1 complex was stabilized by Gibb's free energy of -13.235 kcal/mol which corresponded to the binding affinity of 5.095 × 10 9  M -1 . This is the first study wherein hesperidin has been identified as a potential inhibitor of PLK-1. Further design and optimization of the hesperidin scaffold as an inhibitor of PLK-1 kinase domain is highly recommended. Copyright © 2018 Elsevier B.V. All rights reserved.

Signet-ring cell lymphoma of T-cell origin. An immunocytochemical and ultrastructural study relating giant vacuole formation to cytoplasmic sequestration of surface membrane.

PubMed

Grogan, T M; Richter, L C; Payne, C M; Rangel, C S

1985-09-01

In contrast to previous accounts of signet-ring lymphoma as a B-cell neoplasm, we report a case of signet-ring, large-cell lymphoma of T-cell lineage. Immunologic and ultrastructural studies were performed on a subcutaneous mass noted initially, as well as on an enlarged lymph node that developed later, in a 69-year-old man. Immunologic assessment indicated strong expression of T-helper antigen (Leu 3a + b), universal T-antigens (Leu 1, 5), and Ia. There was an absence of T-suppressor/cytotoxic antigen (Leu 2a), universal T-antigens (Leu 4, 9), and immunoglobulin light and heavy chains. Collectively, these findings indicate a mature T-cell lymphoma of T-helper type in an activated (Ia+) state. In contrast to previous reports of T-cell and Ia occurring solely as surface antigens, we demonstrated pools of cytoplasmic Leu 1, 3, 5 and Ia that displaced the nucleus. The ultrastructure of the giant cytoplasmic vacuoles was identical to the microvesicle-containing vacuoles reported in signet-ring cell lymphomas of B-cell lineage. In our case of T-cell lineage, we found substantial evidence of endocytosis by the neoplastic cells and numerous giant multivesicular bodies. The pools of cytoplasmic T and Ia antigens may result from abnormal internalization of surface T-antigens or the sequestration of T-antigen-containing Golgi-derived vesicles. Our combined immunologic and ultrastructural findings suggest that aberrant membrane recycling may be the common denominator of signet-ring formation in both B- and T-cell signet-ring lymphomas.

Subcellular localization of pituitary enzymes

NASA Technical Reports Server (NTRS)

Smith, R. E.

1970-01-01

A cytochemical procedure is reported for identifying subcellular sites of enzymes hydrolyzing beta-naphthylamine substrates, and to study the sites of reaction product localization in cells of various tissues. Investigations using the substrate Leu 4-methoxy-8-naphthylamine, a capture with hexonium pararosaniline, and the final chelation of osmium have identified the hydrolyzing enzyme of rat liver cells; this enzyme localized on cell membranes with intense deposition in the areas of the parcanaliculi. The study of cells in the anterior pituitary of the rat showed the deposition of reaction product on cell membrane; and on the membranes of secretion granules contained within the cell. The deposition of reaction product on the cell membrane however showed no increase or decrease with changes in the physiological state of the gland and release of secretion granules from specific cells.

Survey of undeclared soy allergen levels in the most frequently recalled food categories with or without precautionary labelling.

PubMed

Khuda, Sefat E; Sharma, Girdhari M; Gaines, Dennis; Do, Andrew B; Pereira, Marion; Chang, Michael; Ferguson, Martine; Williams, Kristina M

2016-08-01

A comprehensive study was designed to determine the frequency and levels of soy allergen in packaged bakery and snack food products. A representative sample of products with no soy allergen disclosed on the label was analysed using two widely used enzyme-linked immunosorbent assay (ELISA) methods. Samples were chosen that either had no soy identified on the product label or which had a soy precautionary statement. Among 558 bakery and snack products, soy protein was detected in 17% of the products using the Neogen (NE) kit and 11% of the products using the Elisa Systems (ES) kit. The disagreement rates between kits were 8.8% for bakery products and 3.3% for snack products. Overall soy protein was detected at higher frequency in bakery products than in snack foods. Among 284 bakery samples, soy protein was detected in 25% of the samples with no precautionary statement and 19% of the samples which had a precautionary statement. Among 274 snack samples, soy protein was detected in 11% of the samples with no precautionary statement and 9% of the samples which had a precautionary statement. The sample repeatability was at an acceptable level (< 9%) for each method and food commodity. The reproducibility between kits was 23% for bakery foods and 36% for snack foods. None of the bakery (21) and snack (6) products without precautionary labelling (measured level > 5 ppm) had a higher level of soy protein per serving compared with the eliciting dose10 (ED10) of 10.6 mg for soy allergic patients. But the level of soy protein per serving may be clinically relevant to a subpopulation of soy allergic patients if a more stringent eliciting dose is applied. These findings emphasise that suitable detection methodologies and references doses are crucial for labelling accuracy and the safety of soy allergic consumers.

Hb L'Aquila [beta106(G8)Leu-->Val, CTG-->GTG]: a novel thalassemic hemoglobin variant.

PubMed

Amato, Antonio; Cappabianca, Maria Pia; Ponzini, Donatella; Rinaldi, Silvana; Biagio, Paola Di; Foglietta, Enrica; Grisanti, Paola; Mastropietro, Fabrizio

2007-01-01

A new beta-globin variant at codon 106 (CTG-->GTG), and which we named Hb L'Aquila [beta106(G8)Leu-->Val], was detected by DNA analysis. The proband and her father presented with the features of a mild beta(+)-thalassemia (thal), confirmed by their alpha/beta-globin chain biosynthesis ratios.

Analysis of the Reactor Physics of Low-Enrichment Fuel for the INL Advanced Test Reactor in support of RERTR

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mark DeHart; William Skerjanc; Sean Morrell

2012-06-01

Analysis of the performance of the ATR with a LEU fuel design shows promise in terms of a core design that will yield the same neutron sources in target locations. A proposed integral cladding burnable absorber design appears to meet power profile requirements that will satisfy power distributions for safety limits. Performance of this fuel design is ongoing; the current work is the initial evaluation of the core performance of this fuel design with increasing burnup. Results show that LEU fuel may have a longer lifetime that HEU fuel however, such limits may be set by mechanical performance of themore » fuel rather that available reactivity. Changes seen in the radial fuel power distribution with burnup in LEU fuel will require further study to ascertain the impact on neutron fluxes in target locations. Source terms for discharged fuel have also been studied. By its very nature, LEU fuel produces much more plutonium than is present in HEU fuel at discharge. However, the effect of the plutonium inventory appears to have little affect on radiotoxicity or decay heat in the fuel.« less

N-AC-l-Leu-PEI-mediated miR-34a delivery improves osteogenic differentiation under orthodontic force.

PubMed

Yu, Wenwen; Zheng, Yi; Yang, Zhujun; Fei, Hongbo; Wang, Yang; Hou, Xu; Sun, Xinhua; Shen, Yuqin

2017-12-15

Rare therapeutic genes or agents are reported to control orthodontic bone remodeling. MicroRNAs have recently been associated with bone metabolism. Here, we report the in vitro and in vivo effects of miR-34a on osteogenic differentiation under orthodontic force using an N -acetyl-L-leucine-modified polyethylenimine ( N -Ac-l-Leu-PEI) carrier. N -Ac-l-Leu-PEI exhibited low cytotoxicity and high miR-34a transfection efficiency in rat bone mineral stem cells and local alveolar bone tissue. After transfection, miR-34a enhanced the osteogenic differentiation of Runx2 and ColI , Runx2 and ColI protein levels, and early osteogenesis function under orthodontic strain in vitro . MiR-34a also enhanced alveolar bone remodeling under orthodontic force in vivo , as evidenced by elevated gene and protein expression, upregulated indices of alveolar bone anabolism, and diminished tooth movement. We determined that the mechanism miR-34a in osteogenesis under orthodontic force may be associated with GSK-3β. These results suggested that miR-34a delivered by N -Ac-l-Leu-PEI could be a potential therapeutic target for orthodontic treatment.

Dysregulated autophagy in restrictive cardiomyopathy due to Pro209Leu mutation in BAG3.

PubMed

Schänzer, A; Rupp, S; Gräf, S; Zengeler, D; Jux, C; Akintürk, H; Gulatz, L; Mazhari, N; Acker, T; Van Coster, R; Garvalov, B K; Hahn, A

2018-03-01

Myofibrillary myopathies (MFM) are hereditary myopathies histologically characterized by degeneration of myofibrils and aggregation of proteins in striated muscle. Cardiomyopathy is common in MFM but the pathophysiological mechanisms are not well understood. The BAG3-Pro209Leu mutation is associated with early onset MFM and severe restrictive cardiomyopathy (RCM), often necessitating heart transplantation during childhood. We report on a young male patient with a BAG3-Pro209Leu mutation who underwent heart transplantation at eight years of age. Detailed morphological analyses of the explanted heart tissue showed intracytoplasmic inclusions, aggregation of BAG3 and desmin, disintegration of myofibers and Z-disk alterations. The presence of undegraded autophagosomes, seen by electron microscopy, as well as increased levels of p62, LC3-I and WIPI1, detected by immunohistochemistry and western blot analyses, indicated a dysregulation of autophagy. Parkin and PINK1, proteins involved in mitophagy, were slightly increased whereas mitochondrial OXPHOS activities were not altered. These findings indicate that altered autophagy plays a role in the pathogenesis and rapid progression of RCM in MFM caused by the BAG3-Pro209Leu mutation, which could have implications for future therapeutic strategies. Copyright © 2018 Elsevier Inc. All rights reserved.

Urate oxidase is imported into peroxisomes recognizing the C-terminal SKL motif of proteins.

PubMed

Miura, S; Oda, T; Funai, T; Ito, M; Okada, Y; Ichiyama, A

1994-07-01

Rat liver urate oxidase synthesized from cDNA through coupled transcription and translation was incubated at 26 degrees C for 60 min with purified peroxisomes from rat liver. Urate oxidase was efficiently imported into the peroxisomes, as determined by resistance to externally added proteinase K. The amount of imported urate oxidase increased with time and the import was temperature dependent. A synthetic peptide composed of the C-terminal 10 amino acid residues of acyl-CoA oxidase (the C-terminal tripeptide is Ser-Lys-Leu) inhibited the import of urate oxidase, whereas other peptides, in which the C-terminal Ser-Lys-Leu (SKL) sequence was deleted or mutated, were not effective. Two mutant urate oxidase proteins in which the C-terminal Ser-Arg-Leu (SRL) sequence was deleted or mutated to Ser-Glu-Leu (SEL) were not imported into peroxisomes. With substitution of a lysine residue for arginine in the SRL tripeptide at the C-terminus the import activity was retained. These results show that urate oxidase is important into peroxisomes via a common pathway with acyl-CoA oxidase, and that the C-terminal SRL sequence functions as a peroxisomal-targeting signal.

The Leu72Met polymorphism of the ghrelin gene is significantly associated with binge eating disorder.

PubMed

Monteleone, Palmiero; Tortorella, Alfonso; Castaldo, Eloisa; Di Filippo, Carmela; Maj, Mario

2007-02-01

The pathophysiological mechanisms underlying binge eating disorder are poorly understood. Evidence exists for the fact that abnormalities in peptides involved in the regulation of appetite, including ghrelin, may play a role in binge eating behavior. Genes involved in the ghrelin physiology may therefore contribute to the biological vulnerability to binge eating disorder. We examined whether two polymorphisms of the ghrelin gene, the G152A (Arg51Gln) and C214A (Leu72Met), were associated with binge eating disorder. Ninety obese or nonobese women with binge eating disorder and 119 normal weight women were genotyped at the ghrelin gene. Statistical analyses showed that the Leu72Met ghrelin gene variant was significantly more frequent in binge eating disorder patients (chi2=5.940; d.f.=1, P=0.01) and was associated with a moderate, but significant risk to develop binge eating disorder (odds ratio=2.725, 95% confidence interval: 1.168-6.350). Although these data should be regarded as preliminary because of the small sample size, they suggest that the Leu72Met ghrelin gene variant may contribute to the genetic susceptibility to binge eating disorder.

Association between the ghrelin Leu72Met polymorphism and type 2 diabetes risk: a meta-analysis.

PubMed

Liao, Ning; Xie, Zi-Kang; Huang, Jian; Xie, Zheng-Fu

2013-04-01

Data on the association between the ghrelin Leu72Met polymorphism and type 2 diabetes are conflicting. A meta-analysis was performed on this topic. We searched for case-control studies using electronic databases (Medline and PubMed) and reference lists of studies. Odds ratios (OR) and 95% confidence intervals (CI) assuming dominant, recessive and homozygote comparison genetic models were calculated. Six case-control studies involving a total of 3417 cases and 3081 controls were included in this meta-analysis. No association was found between the ghrelin Leu72Met polymorphism and type 2 diabetes risk in the overall population in dominant, recessive and homozygote comparison models. However, in subgroup analyses stratified by ethnicity, we found that the risk for type 2 diabetes was decreased in subjects with Met72+ genotypes in Caucasians (OR=0.79, 95% CI: 0.64-0.98, P(z)=0.030). The ghrelin Leu72Met polymorphism was protective against type 2 diabetes in Caucasians. Future studies performed in larger sample size are needed to allow a more definitive conclusion. Copyright © 2012 Elsevier B.V. All rights reserved.

Analysis of Accidents at the Pakistan Research Reactor-1 Using Proposed Mixed-Fuel (HEU and LEU) Core

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bokhari, Ishtiaq H.

2004-12-15

The Pakistan Research Reactor-1 (PARR-1) was converted from highly enriched uranium (HEU) to low-enriched uranium (LEU) fuel in 1991. The reactor is running successfully, with an upgraded power level of 10 MW. To save money on the purchase of costly fresh LEU fuel elements, the use of less burnt HEU spent fuel elements along with the present LEU fuel elements is being considered. The proposal calls for the HEU fuel elements to be placed near the thermal column to gain the required excess reactivity. In the present study the safety analysis of a proposed mixed-fuel core has been carried outmore » at a calculated steady-state power level of 9.8 MW. Standard computer codes and correlations were employed to compute various parameters. Initiating events in reactivity-induced accidents involve various modes of reactivity insertion, namely, start-up accident, accidental drop of a fuel element on the core, flooding of a beam tube with water, and removal of an in-pile experiment during reactor operation. For each of these transients, time histories of reactor power, energy released, temperature, and reactivity were determined.« less

Cells adapted to the proteasome inhibitor 4-hydroxy- 5-iodo-3-nitrophenylacetyl-Leu-Leu-leucinal-vinyl sulfone require enzymatically active proteasomes for continued survival

PubMed Central

Princiotta, Michael F.; Schubert, Ulrich; Chen, Weisan; Bennink, Jack R.; Myung, Jayhyuk; Crews, Craig M.; Yewdell, Jonathan W.

2001-01-01

The proteasome is the primary protease used by cells for degrading proteins and generating peptide ligands for class I molecules of the major histocompatibility complex. Based on the properties of cells adapted to grow in the presence of the proteasome inhibitor 4-hydroxy-5-iodo-3-nitrophenylacetyl-Leu-Leu-leucinal-vinyl sulfone (NLVS), it was proposed that proteasomes can be replaced by alternative proteolytic systems, particularly a large proteolytic complex with a tripeptidyl peptidase II activity. Here we show that NLVS-adapted cells retain sensitivity to a number of highly specific proteasome inhibitors with regard to antigenic peptide generation, accumulation of polyubiquitinated proteins, degradation of p53, and cell viability. In addition, we show that in the same assays (with a single minor exception), NLVS-adapted cells are about as sensitive as nonselected cells to Ala-Ala-Phe-chloromethylketone, a specific inhibitor of tripeptidyl peptidase II activity. Based on these findings, we conclude that proteasomes still have essential proteolytic functions in adapted cells that are not replaced by Ala-Ala-Phe-chloromethylketone-sensitive proteases. PMID:11149939

Forced Ambiguity of the Leucine Codons for Multiple-Site-Specific Incorporation of a Noncanonical Amino Acid

PubMed Central

Kwon, Inchan; Choi, Eun Sil

2016-01-01

Multiple-site-specific incorporation of a noncanonical amino acid into a recombinant protein would be a very useful technique to generate multiple chemical handles for bioconjugation and multivalent binding sites for the enhanced interaction. Previously combination of a mutant yeast phenylalanyl-tRNA synthetase variant and the yeast phenylalanyl-tRNA containing the AAA anticodon was used to incorporate a noncanonical amino acid into multiple UUU phenylalanine (Phe) codons in a site-specific manner. However, due to the less selective codon recognition of the AAA anticodon, there was significant misincorporation of a noncanonical amino acid into unwanted UUC Phe codons. To enhance codon selectivity, we explored degenerate leucine (Leu) codons instead of Phe degenerate codons. Combined use of the mutant yeast phenylalanyl-tRNA containing the CAA anticodon and the yPheRS_naph variant allowed incorporation of a phenylalanine analog, 2-naphthylalanine, into murine dihydrofolate reductase in response to multiple UUG Leu codons, but not to other Leu codon sites. Despite the moderate UUG codon occupancy by 2-naphthylalaine, these results successfully demonstrated that the concept of forced ambiguity of the genetic code can be achieved for the Leu codons, available for multiple-site-specific incorporation. PMID:27028506

Forced Ambiguity of the Leucine Codons for Multiple-Site-Specific Incorporation of a Noncanonical Amino Acid.

PubMed

Kwon, Inchan; Choi, Eun Sil

2016-01-01

Multiple-site-specific incorporation of a noncanonical amino acid into a recombinant protein would be a very useful technique to generate multiple chemical handles for bioconjugation and multivalent binding sites for the enhanced interaction. Previously combination of a mutant yeast phenylalanyl-tRNA synthetase variant and the yeast phenylalanyl-tRNA containing the AAA anticodon was used to incorporate a noncanonical amino acid into multiple UUU phenylalanine (Phe) codons in a site-specific manner. However, due to the less selective codon recognition of the AAA anticodon, there was significant misincorporation of a noncanonical amino acid into unwanted UUC Phe codons. To enhance codon selectivity, we explored degenerate leucine (Leu) codons instead of Phe degenerate codons. Combined use of the mutant yeast phenylalanyl-tRNA containing the CAA anticodon and the yPheRS_naph variant allowed incorporation of a phenylalanine analog, 2-naphthylalanine, into murine dihydrofolate reductase in response to multiple UUG Leu codons, but not to other Leu codon sites. Despite the moderate UUG codon occupancy by 2-naphthylalaine, these results successfully demonstrated that the concept of forced ambiguity of the genetic code can be achieved for the Leu codons, available for multiple-site-specific incorporation.

Loss-of-Flow and Loss-of-Pressure Simulations of the BR2 Research Reactor with HEU and LEU Fuel

DOE Office of Scientific and Technical Information (OSTI.GOV)

Licht, J.; Bergeron, A.; Dionne, B.

2016-01-01

Belgian Reactor 2 (BR2) is a research and test reactor located in Mol, Belgium and is primarily used for radioisotope production and materials testing. The Materials Management and Minimization (M3) Reactor Conversion Program of the National Nuclear Security Administration (NNSA) is supporting the conversion of the BR2 reactor from Highly Enriched Uranium (HEU) fuel to Low Enriched Uranium (LEU) fuel. The reactor core of BR2 is located inside a pressure vessel that contains 79 channels in a hyperboloid configuration. The core configuration is highly variable as each channel can contain a fuel assembly, a control or regulating rod, an experimentalmore » device, or a beryllium or aluminum plug. Because of this variability, a representative core configuration, based on current reactor use, has been defined for the fuel conversion analyses. The code RELAP5/Mod 3.3 was used to perform the transient thermal-hydraulic safety analyses of the BR2 reactor to support reactor conversion. The input model has been modernized relative to that historically used at BR2 taking into account the best modeling practices developed by Argonne National Laboratory (ANL) and BR2 engineers.« less

Identification of Collagen-Derived Hydroxyproline (Hyp)-Containing Cyclic Dipeptides with High Oral Bioavailability: Efficient Formation of Cyclo(X-Hyp) from X-Hyp-Gly-Type Tripeptides by Heating.

PubMed

Taga, Yuki; Kusubata, Masashi; Ogawa-Goto, Kiyoko; Hattori, Shunji

2017-11-01

Cyclic dipeptides (2,5-diketopiperazines) are present in a variety of foods and are reported to demonstrate antioxidant, antidepressant, and other beneficial effects. We recently developed a novel collagen hydrolysate characterized by a high content of X-hydroxyproline (Hyp)-Gly-type tripeptides using ginger protease. In the present study, we found that, through heating, X-Hyp-Gly can be easily converted into Hyp-containing cyclic dipeptides. After heating for 3 h at 85 °C and pH 4.8, Ala-Hyp-Gly was almost completely cyclized to cyclo(Ala-Hyp), in contrast to a slight cyclization of Ala-Hyp. The contents of cyclo(Ala-Hyp) and cyclo(Leu-Hyp) reached 0.5-1% (w/w) each in the ginger-degraded collagen hydrolysate under the heating conditions. Oral administration experiments using mice revealed that cyclo(Ala-Hyp) and cyclo(Leu-Hyp) were absorbed into the blood at markedly higher efficiencies compared to collagenous oligopeptides, including Pro-Hyp. The high productivity and oral bioavailability of the collagen-specific cyclic dipeptides suggest significant health benefits of the heat-treated ginger-degraded collagen hydrolysate.

A new immunization procedure for the obtention of anti-leucine enkephalin antibodies. Part I. Immunization procedure and physicochemical characteristics of antibodies.

PubMed

Cupo, A; Vion-Dury, J; Jarry, T

1986-10-01

We described here a new immunization procedure to obtain high titre and high specific antibodies against Leu-enkephalin (LE). The immunogen form is composed of one part of LE conjugate and one part of LE-Arg6 conjugate. We have observed an increase of titre, affinity and specificity of the antibodies in the coimmunization procedure compared to those obtained by conventional immunization involving only the LE conjugate. The Leu-enkephalin antibodies exhibit a high affinity (KD 8 X 10(-12) M) and we are able to detect the Leu-enkephalin at the 10(-15) mole level. These LE antibodies are highly specific of the C part of LE peptide and cross-react weakly with Met-enkephalin (1%).

CREATION OF THE MODEL ADDITIONAL PROTOCOL

DOE Office of Scientific and Technical Information (OSTI.GOV)

Houck, F.; Rosenthal, M.; Wulf, N.

In 1991, the international nuclear nonproliferation community was dismayed to discover that the implementation of safeguards by the International Atomic Energy Agency (IAEA) under its NPT INFCIRC/153 safeguards agreement with Iraq had failed to detect Iraq's nuclear weapon program. It was now clear that ensuring that states were fulfilling their obligations under the NPT would require not just detecting diversion but also the ability to detect undeclared materials and activities. To achieve this, the IAEA initiated what would turn out to be a five-year effort to reappraise the NPT safeguards system. The effort engaged the IAEA and its Member Statesmore » and led to agreement in 1997 on a new safeguards agreement, the Model Protocol Additional to the Agreement(s) between States and the International Atomic Energy Agency for the Application of Safeguards. The Model Protocol makes explicit that one IAEA goal is to provide assurance of the absence of undeclared nuclear material and activities. The Model Protocol requires an expanded declaration that identifies a State's nuclear potential, empowers the IAEA to raise questions about the correctness and completeness of the State's declaration, and, if needed, allows IAEA access to locations. The information required and the locations available for access are much broader than those provided for under INFCIRC/153. The negotiation was completed in quite a short time because it started with a relatively complete draft of an agreement prepared by the IAEA Secretariat. This paper describes how the Model Protocol was constructed and reviews key decisions that were made both during the five-year period and in the actual negotiation.« less

Chinese proprietary medicine in Singapore: regulatory control of toxic heavy metals and undeclared drugs.

PubMed

Koh, H L; Woo, S O

2000-11-01

Traditional Chinese medicine (TCM) is gaining popularity as a form of complementary and alternative medicine. Reports of efficacy of TCM are increasing in numbers. TCM includes both crude Chinese medicinal materials (plants, animal parts and minerals) and Chinese proprietary medicine (CPM) [final dosage forms]. Despite the belief that CPM and herbal remedies are of natural origin, unlike Western medicine, and are hence safe and without many adverse effects, there have been numerous reports of adverse effects associated with herbal remedies. Factors affecting the safety of herbal medicines include intrinsic toxicity, adulteration, substitution, contamination, misidentification, lack of standardisation, incorrect preparation and/or dosage and inappropriate labelling and/or advertising. Hence, new regulations on the control of CPM were enforced in Singapore with effect from 1 September 1999. These include licensing and labelling requirements, as well as control of microbial contamination. This article also reviews reports of excessive toxic heavy metals and undeclared drugs in CPM in Singapore between 1990 and 1997. The names, uses, toxic heavy metal or drug detected and the year of detection are tabulated. Information on the brand or manufacturer's name are provided whenever available. The public and healthcare professionals should be better informed of the basic concept of TCM and its usefulness, as well as the potential adverse effects associated with its use. Greater control over the safety and quality of CPM could be achieved through good manufacturing practice, regulatory control, research, education, reporting usage of Chinese medicine (as in drug history) as well as reporting of adverse events.

Determination of mammalian deoxyribonucleic acid (DNA) in commercial vegetarian and vegan diets for dogs and cats.

PubMed

Kanakubo, K; Fascetti, A J; Larsen, J A

2017-02-01

The determination of undeclared ingredients in pet food using different analytical methods has been reported in recent years, raising concerns regarding adequate quality control, dietary efficacy and the potential for purposeful adulteration. The objective of this study was to determine the presence or absence of mammalian DNA using multiplex polymerase chain reaction (PCR) on diets marketed as vegetarian or vegan for dogs and cats. The diets were tested in duplicate; two samples were purchased approximately 3 to 4 months apart with different lot numbers. Multiplex PCR-targeted mitochondrial DNA with two species-specific primers was used to amplify and sequence two sections of the cytochrome b gene for each of the 11 mammalian species. Half of the diets assessed (7/14) were positive for one or more undeclared mammalian DNA source (bovine, porcine, or ovine), and the result was repeatable for one or more species in six diets. While most of the detected DNA was found at both time points, in some cases, the result was positive only at one time point, suggesting the presence may have been due to unintentional cross-contact with animal-sourced ingredients. DNA from feline, cervine, canine, caprine, equine, murine (mouse and rat) and leporine was not identified in any samples. However, evidence of mammalian DNA does not confirm adulteration by the manufacturer nor elucidate its clinical significance when consumed by animals that may benefit from a vegetarian or vegan diet. Journal of Animal Physiology and Animal Nutrition © 2016 Blackwell Verlag GmbH.

77 FR 19642 - Low Enriched Uranium From France: Final Results of Antidumping Duty Changed Circumstances Review

Federal Register 2010, 2011, 2012, 2013, 2014

2012-04-02

... in U.S. customs territory, and (ii) are re-exported within eighteen (18) months of entry of the LEU... amend the scope of the order and to extend the deadline for the re-exportation of this sole LEU entry... transporter(s) while in U.S. customs territory, and (ii) are re-exported within eighteen (18) months of entry...

Sequestosome-1 (SQSTM1) sequence variants in ALS cases in the UK: prevalence and coexistence of SQSTM1 mutations in ALS kindred with PDB.

PubMed

Kwok, Chun T; Morris, Alex; de Belleroche, Jacqueline S

2014-04-01

Mutations in the SQSTM1 gene have been reported to be associated with amyotrophic lateral sclerosis (ALS). We sought to determine the frequency of these mutations in a UK familial ALS (FALS) cohort. Sequences of all eight exons of the SQSTM1 gene were analysed in index cases from 61 different FALS kindred lacking known FALS mutations. Six exonic variants c.463G>A, p.(Glu155Lys), c.822G>C, p.(Glu274Asp), c.888G>T, p.(=), c.954C>T, p.(=), c.1038G>A, p.(=) and c.1175C>T, p.(Pro392Leu) were identified in five FALS index cases, three of which were non-synonymous and three were synonymous. One index case harboured three variants (c.822G>C, c.888G>T and c.954C>T), and a second index case harboured two variants (c.822G>C and c.954C>T). Only the p.(Pro392Leu) and p.(Glu155Lys) mutations were predicted to be pathogenic. In one p.(Pro392Leu) kindred, the carrier developed both ALS and Paget's disease of bone (PDB), and, in the p.(Glu155Lys) kindred, the father of the proband developed PDB. All p.(Pro392Leu) carriers were heterozygous for a previously reported founder haplotype for PDB, where this mutation has an established causal effect. The frequency of the p.(Pro392Leu) mutation in this UK FALS cohort was 2.3% and 0.97% overall including three previously screened FALS cohorts. Our results confirm the presence of the p.(Pro392Leu) SQSTM1 mutation in FALS. This mutation is the most common SQSTM1 mutation found in ALS to date, and a likely pathogenicity is supported by having an established causal role in PDB. The occurrence of the same mutation in ALS and PDB is indicative of a common pathogenic pathway that converges on protein homeostasis.

Evolution of the insulin molecule: insights into structure-activity and phylogenetic relationships.

PubMed

Conlon, J M

2001-07-01

The conformation of insulin in the crystalline state has been known for more than 30 years but there remains uncertainty regarding the biologically active conformation and the structural features that constitute the receptor-binding domain. The primary structure of insulin has been determined for at least 100 vertebrate species. In addition to the invariant cysteines, only ten amino acids (GlyA1, IleA2, ValA3, TyrA19, LeuB6, GlyB8, LeuB11, ValB12, GlyB23 and PheB24) have been fully conserved during vertebrate evolution. This observation supports the hypothesis derived from alanine-scanning mutagenesis studies that five of these invariant residues (IleA2, ValA3, TyrA19, GlyB23, and Phe24) interact directly with the receptor and five additional conserved residues (LeuB6, GlyB8, LeuB11, GluB13 and PheB25) are important in maintaining the receptor-binding conformation. With the exception of the hagfish, only conservative substitutions are found at B13 (Glu --> Asp) and B25(Phe --> Tyr). In contrast, amino acid residues that were also considered to be important in receptor binding based upon the crystal structure of insulin (GluA4, GlnA5, AsnA21, TyrB16, TyrB26) have been much less well conserved and are probably not components of the receptor-binding domain. The hypothesis that LeuA13 and LeuB17 form part of a second receptor-binding site in the insulin molecule finds some support in terms of their conservation during vertebrate evolution, although the site is probably absent in some hystricomorph insulins. In general, the amino acid sequences of insulins are not useful in cladistic analyses especially when evolutionary distant taxa are compared but, among related species in a particular order or family, the presence of unusual structural features in the insulin molecule may permit a meaningful phylogenetic inference. For example, analysis of insulin sequences supports monophyletic status for Dipnoi, Elasmobranchii, Holocephali and Petromyzontiformes.

Structural comparison of complexes of methotrexate analogues with Lactobacillus casei dihydrofolate reductase by two-dimensional /sup 1/H NMR at 500 MHz

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hammond, S.J.; Birdsall, B.; Feeney, J.

1987-12-29

The authors have used two-dimensional (2D) NMR methods to examine complexes of Lactobacillus casei dihydrofolate reductase and methotrexate (MTX) analogues having structural modifications of the benzoyl ring and also the glutamic acid moiety. Assignments of the /sup 1/H signals in the spectra of the various complexes were made by comparison of their 2D spectra with those complexes containing methotrexate where we have previously assigned resonances from 32 of the 162 amino acid residues. In the complexes formed with the dihalomethotrexate analogues, the glutamic acid and pteridine ring moieties were shown to bind to the enzyme in a manner similar tomore » that found in the methotrexate-enzyme complex. Perturbations in /sup 1/H chemical shifts of protons in Phe-49, Leu-54, and Leu-27 and the methotrexate H7 and NMe protons were observed in the different complexes and were accounted for by changes in orientation of the benzoyl ring in the various complexes. Binding of oxidized or reduced coenzyme to the binary complexes did not result in different shifts for Leu-27, Leu-54, or Leu-19 protons, and thus, the orientation of the benzoyl ring of the methotrexate analogues is not perturbed greatly by the presence of either oxidized or reduced coenzyme. In the complex with the ..gamma..-monoamide analog, the /sup 1/H signals of assigned residues in the protein had almost identical shifts with the corresponding protons in the methotrexate-enzyme complex for all residues except His-28 and, to a lesser extent, Leu-27. This indicates that while the His-28 interaction with the MTX ..gamma..-CO/sub 2//sup -/ is no longer present in this complex with the ..gamma..-amide, there has not been a major change in the overall structure of the two complexes. This behavior contrasts to that of the ..cap alpha..-amide complex where /sup 1/H signals from protons in several amino acid residues are different compared with their values in the complex formed with methotrexate.« less

Analysis of the mechanism of activation of cAMP-dependent protein kinase through the study of mutants of the yeast regulatory subunit.

PubMed

Zaremberg, V; Moreno, S

1996-04-01

Spontaneous mutations in the gene which encodes the regulatory subunit of cAMP-dependent protein kinase (PKA) of Saccharomyces cerevisiae (BCY1) have been isolated previously [Cannon, J. F., Gibbs, J. B. & Tatchell, K. (1986) Genetics 113, 247-264] by selection of ras2::LEU2 revertants that grew on non-fermentable carbon sources. The revertants were placed into groups of increasing severity based on the number of PKA-dependent traits affected [Cannon, J. F., Gitan, R. & Tatchell, K. (1990) J. Biol. Chem. 265, 11897-11904]. In this work the ras2 mutation has been crossed out in each bcy1 allele and the phenotypes of these mutants have been assessed. The order of severity of the mutants in both genetic backgrounds is maintained but the severity of each mutant in the normal background is higher than in the ras2::LEU2 background. Total catalytic-subunit and regulatory-subunit activities were measured in crude extracts of the bcy1 ras2::LEU2 mutants. With one exception (bcy1-6) the calculated regulatory subunit/catalytic subunit ratios of the bcy1 mutants relative to that of wild-type cells were greater than one. The dependence of PKA activity on cAMP was measured in permeabilized cells. The strains show an activity ratio in the absence and presence of cAMP in the range 0.5-1 for Kemptide phosphorylation. Overexpression of the high-affinity cAMP phosphodiesterase gene (PDE2) in the bcy1 ras2::LEU2 strains did not alter their PKA-dependent phenotypes. However, transformants were not observed from the parental ras2::LEU2 strain and the bcy1-6 ras2::LEU2 strain. The results are discussed with respect to a hypothesis for the molecular mechanism of the differential reversal of ras2 phenotypes by the bcy1 alleles. Mutations in the regulatory subunit are predicted to affect the structure of the holoenzyme such that the catalytic subunit is capable of maintaining an active catalytic state, without the need to dissociate from the regulatory subunit.

Neutronics, steady-state, and transient analyses for the Poland MARIA reactor for irradiation testing of LEU lead test fuel assemblies from CERCA : ANL independent verification results.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Garner, P. L.; Hanan, N. A.

The MARIA reactor at the Institute of Atomic Energy (IAE) in Swierk (30 km SE of Warsaw) in the Republic of Poland is considering conversion from high-enriched uranium (HEU) to low-enriched uranium (LEU) fuel assemblies (FA). The FA design in MARIA is rather unique; a suitable LEU FA has never been designed or tested. IAE has contracted with CERCA (the fuel supply portion of AREVA in France) to supply 2 lead test assemblies (LTA). The LTAs will be irradiated in MARIA to burnup level of at least 40% for both LTAs and to 60% for one LTA. IAE may decidemore » to purchase additional LEU FAs for a full core conversion after the test irradiation. The Reactor Safety Committee within IAE and the National Atomic Energy Agency in Poland (PAA) must approve the LTA irradiation process. The approval will be based, in part, on IAE submitting revisions to portions of the Safety Analysis Report (SAR) which are affected by the insertion of the LTAs. (A similar process will be required for the full core conversion to LEU fuel.) The analysis required was established during working meetings between Argonne National Laboratory (ANL) and IAE staff during August 2006, subsequent email correspondence, and subsequent staff visits. The analysis needs to consider the current high-enriched uranium (HEU) core and 4 core configurations containing 1 and 2 LEU LTAs in various core positions. Calculations have been performed at ANL in support of the LTA irradiation. These calculations are summarized in this report and include criticality, burn-up, neutronics parameters, steady-state thermal hydraulics, and postulated transients. These calculations have been performed at the request of the IAE staff, who are performing similar calculations to be used in their SAR amendment submittal to the PAA. The ANL analysis has been performed independently from that being performed by IAE and should only be used as one step in the verification process.« less

Use of LEU in the aqueous homogeneous medical isotope production reactor

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ball, R.M.

1997-08-01

The Medical Isotope Production Reactor (MIPR) is an aqueous solution of uranyl nitrate in water, contained in an aluminum cylinder immersed in a large pool of water which can provide both shielding and a medium for heat exchange. The control rods are inserted at the top through re-entrant thimbles. Provision is made to remove radiolytic gases and recombine emitted hydrogen and oxygen. Small quantities of the solution can be continuously extracted and replaced after passing through selective ion exchange columns, which are used to extract the desired products (fission products), e.g. molybdenum-99. This reactor type is known for its largemore » negative temperature coefficient, the small amount of fuel required for criticality, and the ease of control. Calculation using TWODANT show that a 20% U-235 enriched system, water reflected can be critical with 73 liters of solution.« less

GPX1 Pro198Leu polymorphism and GSTM1 deletion do not affect selenium and mercury status in mildly exposed Amazonian women in an urban population.

PubMed

Rocha, Ariana V; Rita Cardoso, Bárbara; Zavarize, Bruna; Almondes, Kaluce; Bordon, Isabella; Hare, Dominic J; Teixeira Favaro, Déborah Inês; Franciscato Cozzolino, Silvia Maria

2016-11-15

Mercury is potent toxicant element, but its toxicity can be reduced by forming a complex with selenium for safe excretion. Considering the impact of mercury exposure in the Amazon region and the possible interaction between these two elements, we aimed to assess the effects of Pro198Leu polymorphism to GPX1 and GSTM1 deletion, on mercury levels in a population from Porto Velho, an urban locality in the Brazilian Amazon region. Two hundred women from the capital city of Rondônia state were recruited for this study with 149 deemed suitable to participate. We assessed dietary intake using 24-hour recall. Selenium levels in plasma and erythrocytes were measured using hydride generation quartz tube atomic absorption spectroscopy and total hair mercury using cold vapor atomic absorption spectrometry. Oxidative stress parameters (GPx activity, oxygen radical absorbency capacity [ORAC] and malondialdehyde [MDA]) were also analyzed. All participants were genotyped for Pro198Leu polymorphism and GSTM1 deletion. We observed that this population presented high prevalence of selenium deficiency, and also low levels of mercury, likely due to food habits that did not include selenium-rich food sources or significant consumption of fish (mercury biomagnifiers) regularly. Univariate statistical analysis showed that Pro198Leu and GSTM1 genotypes did not affect selenium and mercury levels in this population. Pro198Leu polymorphism and GSTM1 deletion had no effect on mercury levels in mildly exposed people, suggesting these genetic variants impact mercury levels only in highly exposed populations. Copyright © 2016 Elsevier B.V. All rights reserved.

Effect of 8-week leucine supplementation and resistance exercise training on muscle hypertrophy and satellite cell activation in rats.

PubMed

Lim, Chang Hyun; Gil, Ju Hyun; Quan, Helong; Viet, Dang Ha; Kim, Chang Keun

2018-06-01

We investigated the effects of regular leucine intake and/or resistance exercise training on skeletal muscle hypertrophy and satellite cell activity after the administration of different doses of leucine. Ten-week-old Sprague-Dawley rats were assigned to six groups (n = 7 per group): a control group (Con), two groups receiving either 10% (0.135 g/kg.wt) (Leu10) or 50% (0.675 g/kg.wt) (Leu50) leucine supplementation, and three exercise groups receiving 0% (Ex), 10% (Leu10Ex), and 50% (Leu50Ex) leucine supplementation. The rats performed ladder climbing exercises thrice per week for 8 weeks, and received leucine supplements at the same time daily. Muscle phenotypes were assessed by immunohistochemistry. MyoD, myogenin, and IGF1 protein levels were determined by western blot. The Leu50Ex group displayed significantly higher numbers of positive embryonic myosin fibers (0.35 ± 0.08, 250%) and myonuclei (3.29 ± 0.3, 118.7%) than all other groups. And exercise training groups increased the cross-sectional area, the number of satellite cells and protein expression of MyoD, myogenin, and IGF1alpha relative to the Control group (P < 0.05). However, Only leucine supplementation group did not increase skeletal muscle hypertrophy and satellite cell activity, regardless of the dose (P > 0.05). Leucine intake accompanied by regular exercise training may increase satellite cell activation in skeletal muscles, and improve muscle quality more effectively than continuous leucine ingestion alone. © 2018 The Authors. Physiological Reports published by Wiley Periodicals, Inc. on behalf of The Physiological Society and the American Physiological Society.

Effect of leucine supplementation on fat free mass with prolonged hypoxic exposure during a 13-day trek to Everest Base Camp: a double-blind randomized study.

PubMed

Wing-Gaia, Stacie L; Gershenoff, Dana C; Drummond, Micah J; Askew, E Wayne

2014-03-01

Loss of body weight and fat-free mass (FFM) are commonly noted with prolonged exposure to hypobaric hypoxia. Recent evidence suggests protein supplementation, specifically leucine, may potentially attenuate loss of FFM in subcaloric conditions during normoxia. The purpose of this study was to determine if leucine supplementation would prevent the loss of FFM in subcaloric conditions during prolonged hypoxia. Eighteen physically active male (n = 10) and female (n = 8) trekkers completed a 13-day trek in Nepal to Everest Base Camp with a mean altitude of 4140 m (range 2810-5364 m). In this double-blind study, participants were randomized to ingest either leucine (LEU) (7 g leucine, 93 kcal, 14.5 g whey-based protein) or an isocaloric isonitrogenous control (CON) (0.3 g LEU, 93 kcal, 11.3 g collagen protein) twice daily prior to meals. Body weight, body composition, and circumferences of bicep, thigh, and calf were measured pre- and post-trek. There was a significant time effect for body weight (-2.2% ± 1.7%), FFM (-1.7% ± 1.5%), fat mass (-4.0% ± 6.9%), and circumferences (p < 0.05). However, there was no treatment effect on body weight (CON -2.3 ± 2.0%; LEU -2.2 ± 1.5%), FFM (CON -2.1 ± 1.5%; LEU -1.2 ± 1.6%), fat mass (CON -2.9% ± 5.9%; LEU -5.4% ± 8.1%), or circumferences. Although a significant loss of body weight, FFM, and fat mass was noted in 13 days of high altitude exposure, FFM loss was not attenuated by leucine. Future studies are needed to determine if leucine attenuates loss of FFM with longer duration high altitude exposure.

Characterization of Molecular Determinants of the Conformational Stability of Macrophage Migration Inhibitory Factor: Leucine 46 Hydrophobic Pocket

PubMed Central

El-Turk, Farah; Fauvet, Bruno; Ashrafi, Amer; Ouertatani-Sakouhi, Hajer; Cho, Min-Kyu; Neri, Marilisa; Cascella, Michele; Rothlisberger, Ursula; Pojer, Florence; Zweckstetter, Markus; Lashuel, Hilal

2012-01-01

Macrophage Migration Inhibitory Factor (MIF) is a key mediator of inflammatory responses and innate immunity and has been implicated in the pathogenesis of several inflammatory and autoimmune diseases. The oligomerization of MIF, more specifically trimer formation, is essential for its keto-enol tautomerase activity and probably mediates several of its interactions and biological activities, including its binding to its receptor CD74 and activation of certain signaling pathways. Therefore, understanding the molecular factors governing the oligomerization of MIF and the role of quaternary structure in modulating its structural stability and multifunctional properties is crucial for understanding the function of MIF in health and disease. Herein, we describe highly conserved intersubunit interactions involving the hydrophobic packing of the side chain of Leu46 onto the β-strand β3 of one monomer within a hydrophobic pocket from the adjacent monomer constituted by residues Arg11, Val14, Phe18, Leu19, Val39, His40, Val41, Val42, and Pro43. To elucidate the structural significance of these intersubunit interactions and their relative contribution to MIF’s trimerization, structural stability and catalytic activity, we generated three point mutations where Leu46 was replaced by glycine (L46G), alanine (L46A) and phenylalanine (L46F), and their structural properties, stability, oligomerization state, and catalytic activity were characterized using a battery of biophysical methods and X-ray crystallography. Our findings provide new insights into the role of the Leu46 hydrophobic pocket in stabilizing the conformational state of MIF in solution. Disrupting the Leu46 hydrophobic interaction perturbs the secondary and tertiary structure of the protein but has no effect on its oligomerization state. PMID:23028743

Gain-of-function KCNJ6 Mutation in a Severe Hyperkinetic Movement Disorder Phenotype.

PubMed

Horvath, Gabriella A; Zhao, Yulin; Tarailo-Graovac, Maja; Boelman, Cyrus; Gill, Harinder; Shyr, Casper; Lee, James; Blydt-Hansen, Ingrid; Drögemöller, Britt I; Moreland, Jacqueline; Ross, Colin J; Wasserman, Wyeth W; Masotti, Andrea; Slesinger, Paul A; van Karnebeek, Clara D M

2018-05-29

Here, we describe a fourth case of a human with a de novo KCNJ6 (GIRK2) mutation, who presented with clinical findings of severe hyperkinetic movement disorder and developmental delay, similar to the Keppen-Lubinsky syndrome but without lipodystrophy. Whole-exome sequencing of the patient's DNA revealed a heterozygous de novo variant in the KCNJ6 (c.512T>G, p.Leu171Arg). We conducted in vitro functional studies to determine if this Leu-to-Arg mutation alters the function of GIRK2 channels. Heterologous expression of the mutant GIRK2 channel alone produced an aberrant basal inward current that lacked G protein activation, lost K + selectivity and gained Ca 2+ permeability. Notably, the inward current was inhibited by the Na + channel blocker QX-314, similar to the previously reported weaver mutation in murine GIRK2. Expression of a tandem dimer containing GIRK1 and GIRK2(p.Leu171Arg) did not lead to any currents, suggesting heterotetramers are not functional. In neurons expressing p.Leu171Arg GIRK2 channels, these changes in channel properties would be expected to generate a sustained depolarization, instead of the normal G protein-gated inhibitory response, which could be mitigated by expression of other GIRK subunits. The identification of the p.Leu171Arg GIRK2 mutation potentially expands the Keppen-Lubinsky syndrome phenotype to include severe dystonia and ballismus. Our study suggests screening for dominant KCNJ6 mutations in the evaluation of patients with severe movement disorders, which could provide evidence to support a causal role of KCNJ6 in neurological channelopathies. Copyright © 2018. Published by Elsevier Ltd.

Characterization of molecular determinants of the conformational stability of macrophage migration inhibitory factor: leucine 46 hydrophobic pocket.

PubMed

El-Turk, Farah; Fauvet, Bruno; Ashrafi, Amer; Ouertatani-Sakouhi, Hajer; Cho, Min-Kyu; Neri, Marilisa; Cascella, Michele; Rothlisberger, Ursula; Pojer, Florence; Zweckstetter, Markus; Lashuel, Hilal

2012-01-01

Macrophage Migration Inhibitory Factor (MIF) is a key mediator of inflammatory responses and innate immunity and has been implicated in the pathogenesis of several inflammatory and autoimmune diseases. The oligomerization of MIF, more specifically trimer formation, is essential for its keto-enol tautomerase activity and probably mediates several of its interactions and biological activities, including its binding to its receptor CD74 and activation of certain signaling pathways. Therefore, understanding the molecular factors governing the oligomerization of MIF and the role of quaternary structure in modulating its structural stability and multifunctional properties is crucial for understanding the function of MIF in health and disease. Herein, we describe highly conserved intersubunit interactions involving the hydrophobic packing of the side chain of Leu46 onto the β-strand β3 of one monomer within a hydrophobic pocket from the adjacent monomer constituted by residues Arg11, Val14, Phe18, Leu19, Val39, His40, Val41, Val42, and Pro43. To elucidate the structural significance of these intersubunit interactions and their relative contribution to MIF's trimerization, structural stability and catalytic activity, we generated three point mutations where Leu46 was replaced by glycine (L46G), alanine (L46A) and phenylalanine (L46F), and their structural properties, stability, oligomerization state, and catalytic activity were characterized using a battery of biophysical methods and X-ray crystallography. Our findings provide new insights into the role of the Leu46 hydrophobic pocket in stabilizing the conformational state of MIF in solution. Disrupting the Leu46 hydrophobic interaction perturbs the secondary and tertiary structure of the protein but has no effect on its oligomerization state.

Extreme Population Differences in the Human Zinc Transporter ZIP4 (SLC39A4) Are Explained by Positive Selection in Sub-Saharan Africa

PubMed Central

Pybus, Marc; Andrews, Glen K.; Lalueza-Fox, Carles; Comas, David; Sekler, Israel; de la Rasilla, Marco; Rosas, Antonio; Stoneking, Mark; Valverde, Miguel A.; Vicente, Rubén; Bosch, Elena

2014-01-01

Extreme differences in allele frequency between West Africans and Eurasians were observed for a leucine-to-valine substitution (Leu372Val) in the human intestinal zinc uptake transporter, ZIP4, yet no further evidence was found for a selective sweep around the ZIP4 gene (SLC39A4). By interrogating allele frequencies in more than 100 diverse human populations and resequencing Neanderthal DNA, we confirmed the ancestral state of this locus and found a strong geographical gradient for the derived allele (Val372), with near fixation in West Africa. In extensive coalescent simulations, we show that the extreme differences in allele frequency, yet absence of a classical sweep signature, can be explained by the effect of a local recombination hotspot, together with directional selection favoring the Val372 allele in Sub-Saharan Africans. The possible functional effect of the Leu372Val substitution, together with two pathological mutations at the same codon (Leu372Pro and Leu372Arg) that cause acrodermatitis enteropathica (a disease phenotype characterized by extreme zinc deficiency), was investigated by transient overexpression of human ZIP4 protein in HeLa cells. Both acrodermatitis mutations cause absence of the ZIP4 transporter cell surface expression and nearly absent zinc uptake, while the Val372 variant displayed significantly reduced surface protein expression, reduced basal levels of intracellular zinc, and reduced zinc uptake in comparison with the Leu372 variant. We speculate that reduced zinc uptake by the ZIP4-derived Val372 isoform may act by starving certain pathogens of zinc, and hence may have been advantageous in Sub-Saharan Africa. Moreover, these functional results may indicate differences in zinc homeostasis among modern human populations with possible relevance for disease risk. PMID:24586184

Reconstructed Ancestral Enzymes Impose a Fitness Cost upon Modern Bacteria Despite Exhibiting Favourable Biochemical Properties.

PubMed

Hobbs, Joanne K; Prentice, Erica J; Groussin, Mathieu; Arcus, Vickery L

2015-10-01

Ancestral sequence reconstruction has been widely used to study historical enzyme evolution, both from biochemical and cellular perspectives. Two properties of reconstructed ancestral proteins/enzymes are commonly reported--high thermostability and high catalytic activity--compared with their contemporaries. Increased protein stability is associated with lower aggregation rates, higher soluble protein abundance and a greater capacity to evolve, and therefore, these proteins could be considered "superior" to their contemporary counterparts. In this study, we investigate the relationship between the favourable in vitro biochemical properties of reconstructed ancestral enzymes and the organismal fitness they confer in vivo. We have previously reconstructed several ancestors of the enzyme LeuB, which is essential for leucine biosynthesis. Our initial fitness experiments revealed that overexpression of ANC4, a reconstructed LeuB that exhibits high stability and activity, was only able to partially rescue the growth of a ΔleuB strain, and that a strain complemented with this enzyme was outcompeted by strains carrying one of its descendants. When we expanded our study to include five reconstructed LeuBs and one contemporary, we found that neither in vitro protein stability nor the catalytic rate was correlated with fitness. Instead, fitness showed a strong, negative correlation with estimated evolutionary age (based on phylogenetic relationships). Our findings suggest that, for reconstructed ancestral enzymes, superior in vitro properties do not translate into organismal fitness in vivo. The molecular basis of the relationship between fitness and the inferred age of ancestral LeuB enzymes is unknown, but may be related to the reconstruction process. We also hypothesise that the ancestral enzymes may be incompatible with the other, contemporary enzymes of the metabolic network.

Improving thermal and detergent stability of Bacillus stearothermophilus neopullulanase by rational enzyme design.

PubMed

Ece, Selin; Evran, Serap; Janda, Jan-Oliver; Merkl, Rainer; Sterner, Reinhard

2015-06-01

Neopullulanase, a glycosyl hydrolase from Bacillus stearothermophilus (bsNpl), is a potentially valuable enzyme for starch and detergent industries. However, as the protein is not active at elevated temperatures and high surfactant concentrations, we aimed to increase its stability by rational enzyme design. Nine potentially destabilizing cavities were identified in the crystal structure of the enzyme. Based on computational predictions, these cavities were filled by residues with bulkier side chains. The five Asp46Glu, Val239Leu, Val404Leu, Ser407Thr and Ala566Leu exchanges resulted in a drastic stabilization of bsNpl against inactivation by heat and detergents. The catalytic activity of the variants was identical to the wild-type enzyme. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

Bcl-2-independent induction of apoptosis by neuropeptide receptor antagonist in human small cell lung carcinoma cells.

PubMed

Matsumoto, Y; Kawatani, M; Simizu, S; Tanaka, T; Takada, M; Imoto, M

2000-01-01

The broad-spectrum antagonist of neuropeptide receptor, [D-Arg1, D-Phe5, D-Trp7,9, Leu11]substance P, induced apoptosis selectively in human small cell lung carcinoma (SCLC) cells, which express gastrin-releasing peptide receptor, but not in other types of tumor cells as well as normal cells. The addition of gastrin-releasing peptide or bombesin and the inhibitor of caspase-3 suppressed [D-Arg1, D-Phe5, D-Trp7,9, Leu11]substance P-induced apoptosis. Moreover, [D-Arg1, D-Phe5, D-Trp7,9, Leu11]substance P-induced apoptosis was not suppressed by Bcl-2 over-expression. Thus, blockage of gastrin-releasing peptide receptor-mediated signaling may provide a novel therapeutic option in SCLC which has become resistant to conventional chemotherapeutic agents.

Peptides as modifiers of Na+-induced pinocytosis in starved Amoeba proteus.

PubMed

Josefsson, J O; Johansson, P

1985-01-01

Low concentrations of six peptide hormones; glucagon, vasoactive intestinal peptide, substance P, angiotensin II, lysine-vasopressin, arginine-vasopressin, and the chemotactic peptide fMet-Leu-Phe, activated the capacity for pinocytosis in starved Amoeba proteus. Competitive inhibitors of the chemotactic peptide in leucocytes inhibited activation by fMet-Leu-Phe, suggesting that its action in the amoeba is mediated by specific receptors. The opioid peptides, beta-endorphin, dynorphin (1-13) and leu-enkephalin abolished through a naloxone-sensitive mechanism activation by hormones and several other activating agents. Also, low concentrations of beef and pork insulin inhibited activation by peptide hormones. An insulin analogue of low potency in mammalian cells was inactive in the amoeba. These results support the hypothesis that besides opioid receptors, there may be insulin receptors and possibly receptors for several other peptide hormones in Amoeba proteus.

The Proliferation Security Initiative: A Means to an End for the Operational Commander

DTIC Science & Technology

2009-05-04

The Reduced Enrichment for Research and Test Reactors ( RERTR ) Program develops technology necessary to enable the conversion of civilian...facilities using high enriched uranium (HEU) to low enriched uranium (LEU) fuels and targets. The RERTR Program was initiated by the U.S. Department of...processes have been developed for producing radioisotopes with LEU targets. The RERTR Program is managed by the Office of Nuclear Material Threat

Schwannoma-like tumor in the anterior cranial fossa immunonegative for Leu7 but immunopositive for Schwann/2E.

PubMed

Bohoun, Christian Aïssè; Terakawa, Yuzo; Goto, Takeo; Tanaka, Sayaka; Kuwae, Yuko; Ohsawa, Masahiko; Morisako, Hiroki; Nakajo, Kosuke; Sato, Hidetoshi; Ohata, Kenji; Yokoo, Hideaki

2017-06-01

Schwannoma arising from the olfactory system, often called olfactory groove schwannoma (OGS), is rare, as the olfactory bulb and tract, belonging to the central nervous system, should lack Schwann cells. Another rare entity called olfactory ensheathing cell tumor (OECT) has been reported, which mimics clinical and radiological characteristics of OGS. Here, we report two rare cases of schwannoma-like tumor in the anterior cranial fossa that showed negative staining for Leu7, but positive staining for Schwann/2E, and discuss their origin. Two cases of mass lesions in the anterior cranial fossa in a 26-year-old man and a 24-year-old woman were successfully removed. Morphological examination of these tumors was compatible with a diagnosis of schwannoma. Immunohistochemically, both cases were negative for Leu7, yielding a diagnosis of OECT, but were positive for the schwannoma-specific marker, Schwann/2E. Immunohistochemical staining results in our two cases question the current assumption that OGS and OECT can be distinguished only by Leu7 staining pattern. In conclusion, the origins of OGS and OECT remain to be determined, and further studies in larger numbers of cases are needed to characterize these rare tumors in the anterior cranial fossa. © 2016 Japanese Society of Neuropathology.

Single molecule imaging of conformational dynamics in sodium-coupled transporters

NASA Astrophysics Data System (ADS)

Terry, Daniel S.

Neurotransmitter:sodium symporter (NSS) proteins remove neurotransmitters released into the synapse through a transport process driven by the physiological sodium ion (Na+) gradient. NSSs for dopamine, noradrenaline, and serotonin are targeted by the psychostimulants cocaine and amphetamines, as well as by antidepressants. The crystal structure of LeuT, a prokaryotic NSS homologue, revealed the NSS molecular architecture and has been the basis for extensive structural, biochemical, and computational investigations of the mechanism of transporter proteins with a LeuT-like fold. In this dissertation, the conformational states sampled by LeuT are explored using single-molecule fluorescence resonance energy transfer imaging methods, with special focus on the motions of transmembrane helix 1a that lead to inward release of substrate. We also explored how dynamics are modulated by substrate, Na+, and protons to produce efficient transport. These advances represent a first of a kind study of the dynamics of an integral membrane protein at a truly single-molecule scale. Advances in instrumentation, analysis tools, and organic fluorophores were all required to achieve these goals, and such advances are also described. While these experiments were performed with detergent-solubilized protein, preliminary work suggests that imaging of LeuT in proteoliposomes is feasible and a fluorescence sensor assay could be used to simultaneously detect conformational dynamics and transport function.

Resistance mutations of Pro197, Asp376 and Trp574 in the acetohydroxyacid synthase (AHAS) affect pigments, growths, and competitiveness of Descurainia sophia L.

PubMed

Zhang, Yongzhi; Xu, Yufang; Wang, Shipeng; Li, Xuefeng; Zheng, Mingqi

2017-11-27

D. Sophia is one of the most problematic weed species infesting winter wheat in China, and has evolved high resistance to tribenuron-methyl. Amino acid substitutions at site of Pro197, Asp376 and Trp574 in acetohydroxyacid synthase (AHAS) were mainly responsible for D. sophia resistance to tribenuron-methyl. In this study, D. sophia plant individually homozygous for specific AHAS mutation (Pro197Leu, Pro197His, Pro197Ser, Pro197Thr, Asp376Glu and Trp574Leu) were generated. In addition, the effects of resistance mutations on pigments, growths and competitiveness of susceptible (S) and resistant (R) plants of D. sophia were investigated. The results indicated the R plants carrying Pro197Leu or Pro197His or Asp376Glu or Trp574Leu displayed stronger competitiveness than S plants. The adverse effects on R plants aggravated with the increase of R plants proportion, which made the R plants against domination the weed community in absent of herbicide selection. Therefore, these resistance mutation have no obvious adverse effects on the pigments (chlorophyll a, chlorophyll b and carotenoid), relative growth rates (RGR), leaf area ratio (LAR) and net assimilation rate (NAR) of R plants.

Gender-Associated Impact of Early Leucine Supplementation on Adult Predisposition to Obesity in Rats

PubMed Central

López, Nora; Sánchez, Juana; Palou, Andreu; Serra, Francisca

2018-01-01

Early nutrition plays an important role in development and may constitute a relevant contributor to the onset of obesity in adulthood. The aim of this study was to evaluate the long-term impact of maternal leucine (Leu) supplementation during lactation on progeny in rats. A chow diet, supplemented with 2% Leu, was supplied during lactation (21 days) and, from weaning onwards, was replaced by a standard chow diet. Then, at adulthood (6 months of age), this was replaced with hypercaloric diets (either with high-fat (HF) or high-carbohydrate (HC) content), for two months, to induce obesity. Female offspring from Leu-supplemented dams showed higher increases in body weight and in body fat (62%) than their respective controls; whereas males were somehow protected (15% less fat than the corresponding controls). This profile in Leu-females was associated with altered neuronal architecture at the paraventricular nucleus (PVN), involving neuropeptide Y (NPY) fibers and impaired expression of neuropeptides and factors of the mTOR signaling pathway in the hypothalamus. Interestingly, leptin and adiponectin expression in adipose tissue at weaning and at the time before the onset of obesity could be defined as early biomarkers of metabolic disturbance, predisposing towards adult obesity under the appropriate environment. PMID:29329236

Control of Ion Selectivity in LeuT: Two Na+ Binding Sites with two different mechanisms

PubMed Central

Noskov, Sergei Y.; Roux, Benoît

2016-01-01

The x-ray structure of LeuT, a bacterial homologue of Na+/Cl−-dependent neurotransmitter transporter, provides a great opportunity to better understand the molecular basis of monovalent cation selectivity in ion-coupled transporters. LeuT possesses two ion-binding sites, NA1 and NA2, which are highly selective for Na+. Extensive all-atom free energy molecular dynamics simulations of LeuT embedded in an explicit membrane are performed at different temperatures and various occupancy states of the binding sites to dissect the molecular mechanism of ion selectivity. The results show that the two binding sites display robust selectivity for Na+ over K+ or Li+, the competing ions of most similar radii. Of particular interest, the mechanism primarily responsible for selectivity for each of the two binding sites appears to be different. In site NA1, selectivity for Na+ over K+ arises predominantly from the strong electrostatic field arising from the negatively charged carboxylate group of the leucine substrate coordinating the ion directly. In site NA2, which comprises only neutral ligands, selectivity for Na+ is enforced by the local structural restraints arising from the hydrogen-bonding network and the covalent connectivity of the poly-peptide chain surrounding the ion according to a snug-fit mechanism. PMID:18280500

Overview and Current Status of Analyses of Potential LEU Design Concepts for TREAT

DOE Office of Scientific and Technical Information (OSTI.GOV)

Connaway, H. M.; Kontogeorgakos, D. C.; Papadias, D. D.

2015-10-01

Neutronic and thermal-hydraulic analyses have been performed to evaluate the performance of different low-enriched uranium (LEU) fuel design concepts for the conversion of the Transient Reactor Test Facility (TREAT) from its current high-enriched uranium (HEU) fuel. TREAT is an experimental reactor developed to generate high neutron flux transients for the testing of nuclear fuels. The goal of this work was to identify an LEU design which can maintain the performance of the existing HEU core while continuing to operate safely. A wide variety of design options were considered, with a focus on minimizing peak fuel temperatures and optimizing the powermore » coupling between the TREAT core and test samples. Designs were also evaluated to ensure that they provide sufficient reactivity and shutdown margin for each control rod bank. Analyses were performed using the core loading and experiment configuration of historic M8 Power Calibration experiments (M8CAL). The Monte Carlo code MCNP was utilized for steady-state analyses, and transient calculations were performed with the point kinetics code TREKIN. Thermal analyses were performed with the COMSOL multi-physics code. Using the results of this study, a new LEU Baseline design concept is being established, which will be evaluated in detail in a future report.« less

Mitochondrial gene arrangement of the horseshoe crab Limulus polyphemus L.: conservation of major features among arthropod classes

NASA Technical Reports Server (NTRS)

Staton, J. L.; Daehler, L. L.; Brown, W. M.; Jacobs, D. K. (Principal Investigator)

1997-01-01

Numerous complete mitochondrial DNA sequences have been determined for species within two arthropod groups, insects and crustaceans, but there are none for a third, the chelicerates. Most mitochondrial gene arrangements reported for crustaceans and insect species are identical or nearly identical to that of Drosophila yakuba. Sequences across 36 of the gene boundaries in the mitochondrial DNA (mtDNA) of a representative chelicerate. Limulus polyphemus L., also reveal an arrangement like that of Drosophila yakuba. Only the position of the tRNA(LEU)(UUR) gene differs; in Limulus it is between the genes for tRNA(LEU)(CUN) and ND1. This positioning is also found in onychophorans, mollusks, and annelids, but not in insects and crustaceans, and indicates that tRNA(LEU)(CUN)-tRNA(LEU)(UUR)-ND1 was the ancestral gene arrangement for these groups, as suggested earlier. There are no differences in the relative arrangements of protein-coding and ribosomal RNA genes between Limulus and Drosophila, and none have been observed within arthropods. The high degree of similarity of mitochondrial gene arrangements within arthropods is striking, since some taxa last shared a common ancestor before the Cambrian, and contrasts with the extensive mtDNA rearrangements occasionally observed within some other metazoan phyla (e.g., mollusks and nematodes).

Primary structure of pancreatic polypeptide from four species of Perissodactyla (Przewalski's horse, zebra, rhino, tapir).

PubMed

Henry, J S; Lance, V A; Conlon, J M

1991-12-01

Pancreatic polypeptide (PP) has been purified from extracts of the pancreas of four species of odd-toed ungulates (Perissodactyla): Przewalski's horse, mountain zebra, white rhinoceros, and mountain tapir. The amino acid sequence of Przewalski's horse pancreatic polypeptide was established as Ala-Pro-Met-Glu-Pro-Val-Tyr-Pro-Gly-Asp10-Asn- Ala-Thr-Pro-Glu-Gln-Met-Ala-Gln-Tyr20-Ala-Ala-Glu-Leu-Arg-Arg-Tyr- Ile-Asn-Met30 - Leu-Thr-Arg-Pro-Arg-Tyr.NH2. Zebra PP was identical to Przewalski's horse PP, rhinoceros PP contained three substitutions relative to the horse (Ser for Ala1, Leu for Met3, and Glu for Gln16), and tapir PP contained one substitution relative to the horse (Leu for Met3). On the basis of morphological characteristics and the fossil record, the rhinocerotids are classified with the tapirids in the suborder Ceratomorpha, whereas the horse and zebra belong to a separate suborder, Hippomorpha. On the basis of structural similarity of the PP molecules, however, it would appear that the tapir is more closely related to the horse than to the rhinoceros. These observations provide a further example of the need for extreme caution when inferring taxonomic or phylogenetic relationships between species from the structures of homologous peptides.

High-Resolution Enabled 12-Plex DiLeu Isobaric Tags for Quantitative Proteomics

PubMed Central

2015-01-01

Multiplex isobaric tags (e.g., tandem mass tags (TMT) and isobaric tags for relative and absolute quantification (iTRAQ)) are a valuable tool for high-throughput mass spectrometry based quantitative proteomics. We have developed our own multiplex isobaric tags, DiLeu, that feature quantitative performance on par with commercial offerings but can be readily synthesized in-house as a cost-effective alternative. In this work, we achieve a 3-fold increase in the multiplexing capacity of the DiLeu reagent without increasing structural complexity by exploiting mass defects that arise from selective incorporation of 13C, 15N, and 2H stable isotopes in the reporter group. The inclusion of eight new reporter isotopologues that differ in mass from the existing four reporters by intervals of 6 mDa yields a 12-plex isobaric set that preserves the synthetic simplicity and quantitative performance of the original implementation. We show that the new reporter variants can be baseline-resolved in high-resolution higher-energy C-trap dissociation (HCD) spectra, and we demonstrate accurate 12-plex quantitation of a DiLeu-labeled Saccharomyces cerevisiae lysate digest via high-resolution nano liquid chromatography–tandem mass spectrometry (nanoLC–MS2) analysis on an Orbitrap Elite mass spectrometer. PMID:25405479

Analyses of variant human papillomavirus type-16 E5 proteins for their ability to induce mitogenesis of murine fibroblasts

PubMed Central

Nath, Rahul; Mant, Christine A; Kell, Barbara; Cason, John; Bible, Jon M

2006-01-01

Background Human papillomavirus type 16 (HPV-16) E5 protein co-operates with epidermal growth factor to stimulate mitogenesis of murine fibroblasts. Currently, little is known about which viral amino acids are involved in this process. Using sequence variants of HPV-16 E5 we have investigated their effects upon E5 transcription, cell-cycling and cell-growth of murine fibroblasts. Results We demonstrate that: (i) introduction of Thr64 into the reference E5 sequence of HPV-16 abrogates mitogenic activity: both were poorly transcribed in NIH-3T3 cells; (ii) substitution of Leu44Val65 or, Thr37Leu44Val65 into the HPV-16 E5 reference backbone resulted in high transcription in NIH-3T3 cells, enhanced cell-cycle progression and high cell-growth; and, (iii) inclusion of Tyr8 into the Leu44Val65 backbone inhibited E5 induced cell-growth and repression of p21 expression, despite high transcription levels. Conclusion The effects of HPV-16 E5 variants upon mitosis help to explain why Leu44Val65 HPV-16 E5 variants are most prevalent in 'wild' pathogenic viral populations in the UK. PMID:16899131

Treatment of acute decompensation of maple syrup urine disease in adult patients with a new parenteral amino-acid mixture.

PubMed

Servais, A; Arnoux, J B; Lamy, C; Hummel, A; Vittoz, N; Katerinis, I; Bazzaoui, V; Dubois, S; Broissand, C; Husson, M C; Berleur, M P; Rabier, D; Ottolenghi, C; Valayannopoulos, V; de Lonlay, P

2013-11-01

Acute decompensation of maple syrup urine disease (MSUD) is usually treated by enteral feeding with an amino-acid mixture without leucine (Leu), valine or isoleucine. However, its administration is ineffective in cases of gastric intolerance and some adult patients refuse enteral feeding via a nasogastric tube. We developed a new parenteral amino-acid mixture for patients with MSUD. Seventeen decompensation episodes in four adult patients with MSUD treated with a parenteral amino-acid mixture (group P) were compared to 18 previous episodes in the same patients treated by enteral feeding (group E). The mean Leu concentration at presentation was similar in the groups P and E (1196.9 μmol/L and 1212.2 μmol/L, respectively). The mean decrease in the Leu concentration during the first 3 days of hospitalisation was significantly higher in group P than group E (p = 0.0026); there were no side effects. The mean duration of hospitalisation was similar (4 vs. 4.5 days, p = NS). No patient in group P deteriorated whereas one patient in group E required dialysis. This new parenteral amino-acid mixture is safe and allows efficient Leu concentration decrease during acute MSUD decompensation episodes in adults. Its use avoids the need for nasogastric tube insertion.

DN/DG Screening of Environmental Swipe Samples: FY2016 Report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Glasgow, David C.; Croft, Stephen; Venkataraman, Ramkumar

The Delayed Neutron Delayed Gamma (DNDG) technique provides a new analytical capability to the International Atomic Energy Agency (IAEA) for detecting undeclared nuclear activities. IAEA’s Long Term R&D (LTRD) plan has a stated high urgency need to develop elemental and isotopic signatures of nuclear fuel cycle activities and processes (LTRD 2.2). The new DNDG capability is used to co-detect both uranium and plutonium as an extension of a DN only method that is already being utilized by the IAEA for the analysis of swipes to inform on undeclared nuclear activities. Analytical method involving irradiation of swipe samples potentially containing tracemore » quantities of fissile material in a thermal neutron field, followed by the counting of delayed neutrons, is a well-known technique in the field of safeguards and nonproliferation. It is used for detecting the presence of microscopic amounts of fissile material, (typically a linear combination of 233U, 235U, 239Pu, and 241Pu)and quantifying it in terms of the equivalent mass of 235U. The delayed neutron (DN) technique is very sensitive and is been routinely employed at the High Flux Isotope Reactor (HFIR) facility at Oak Ridge National Laboratory (ORNL). Both uranium and plutonium are of high safeguards value. However, the DN technique is not well suited for distinguishing between U and Pu isotopes since the decay curves overlap closely. The delayed gamma (DG) technique will help detect the presence of 239Pu in a mixture of U and Pu. Thus the DNDG approach combines the best of both worlds; the sensitivity of DN counting and the isotopic specificity of DG counting. The present work seeks to build on the delayed neutron and delayed gamma methods that have been developed at ORNL. It is recognized that the distribution profile of heavy fission products remains fairly invariant for the fissile nuclides whereas the distribution of light fission products varies from one isotope to another. That is, the ratio of the yield of a light fission fragment to a heavy fission fragments is isotope specific. Measurement of the ratio of the net full energy peak (FEP) from low/high mass fission products is an elegant way to characterize the fraction of fissile materials present in a mixture. By empirically calibrating the ratio of the net FEP as a function of known concentration of the binary mixture, one can determine the fraction of fissile isotopes in an unknown sample. In the work done in fiscal year (FY) 2016, samples of single fissile material isotopes as well as binary mixtures were irradiated in a well thermalized irradiation field in the HFIR. Delayed neutron counting was performed using the neutron counter at the HFIR Neutron Activation Analysis (NAA) laboratory. Delayed gamma counting was performed using a shielded high purity germanium (HPGe) detector. Delayed neutron decay curve results highlighted the difficulty of distinguishing between U and Pu isotopes, and the need for including the delayed gamma component. Based on delayed gamma spectrometry, twelve ratios of low mass/high fission product gamma ray FEP have been identified as valid candidates. Linearity of the ratios, as a function of 239Pu fraction in 235U+ 239Pu mixtures, was confirmed for the low mass/high mass candidates that were selected. The DNDG method we are spearheading allows not only the presence of total fissile content to be detected, but whether the material is predominantly U or predominantly Pu, or a mixture. This provides additional SG relevant information.« less

Twenty-Two Years of U.S. Meat and Poultry Product Recalls: Implications for Food Safety and Food Waste.

PubMed

Gorton, Acton; Stasiewicz, Matthew J

2017-04-01

The U.S. Department of Agriculture, Food Safety and Inspection Service maintains a recall case archive of meat and poultry product recalls from 1994 to the present. In this study, we collected all recall records from 1994 to 2015 and extracted the recall date, meat or poultry species implicated, reason for recall, recall class, and pounds of product recalled and recovered. Of a total of 1,515 records analyzed, the top three reasons for recall were contamination with Listeria, undeclared allergens, and Shiga toxin-producing Escherichia coli . Class I recalls (due to a hazard with a reasonable probability of causing adverse health consequences or death) represented 71% (1,075 of 1,515) of the total recalls. The amounts of product recalled and recovered per event were approximately lognormally distributed. The mean amount of product recalled and recovered was 6,800 and 1,000 lb (3,087 and 454 kg), respectively (standard deviation, 1.23 and 1.56 log lb, respectively). The total amount of product recalled in the 22-year evaluation period was 690 million lb (313 million kg), and the largest single recall involved 140 million lb (64 million kg) (21% of the total). In every data category subset, the largest recall represented >10% of the total product recalled in the set. The amount of product recovered was known for only 944 recalls. In 12% of those recalls (110 of 944), no product was recovered. In the remaining recalls, the median recovery was 29% of the product. The number of recalls per year was 24 to 150. Recall counts and amounts of product recalled over the 22-year evaluation period did not regularly increase by year, in contrast to the regular increase in U.S. meat and poultry production over the same time period. Overall, these data suggest that (i) meat and poultry recalls were heavily skewed toward class I recalls, suggesting recalls were focused on improving food safety, (ii) numbers of products and amounts of each product recalled were highly variable but did not increase over time, and (iii) the direct contribution of recalls to the food waste stream was associated with the largest recalls.

NAVSUP Naval Supply Systems Command

DTIC Science & Technology

2011-08-01

commands 4 5 ARE YOU READY TO MARKET TO THE GOVERNMENT? •  Certifications? (Size and NAICS) •  Registrations? (CCR, ORCA ) •  Identifiers? (CAGE...Other existing solutions being evaluated based on cost benefit and small business opportunities 15 SMALL BUSINESS TEAM Jane “Lucy” Leu FLC Puget ... Sound 360-476-1985 Lucy.leu@navy.mil TOP 5 NAICS: 33, 54, 32, 42, 31 Carrodena Johnson FLC Norfolk 757-443-1435 Carrodena.johnson@navy.mil TOP 5

Common folds and transport mechanisms of secondary active transporters.

PubMed

Shi, Yigong

2013-01-01

Secondary active transporters exploit the electrochemical potential of solutes to shuttle specific substrate molecules across biological membranes, usually against their concentration gradient. Transporters of different functional families with little sequence similarity have repeatedly been found to exhibit similar folds, exemplified by the MFS, LeuT, and NhaA folds. Observations of multiple conformational states of the same transporter, represented by the LeuT superfamily members Mhp1, AdiC, vSGLT, and LeuT, led to proposals that structural changes are associated with substrate binding and transport. Despite recent biochemical and structural advances, our understanding of substrate recognition and energy coupling is rather preliminary. This review focuses on the common folds and shared transport mechanisms of secondary active transporters. Available structural information generally supports the alternating access model for substrate transport, with variations and extensions made by emerging structural, biochemical, and computational evidence.

Multi-Leu PACE4 Inhibitor Retention within Cells Is PACE4 Dependent and a Prerequisite for Antiproliferative Activity

PubMed Central

Ly, Kévin; Levesque, Christine; Kwiatkowska, Anna; Ait-Mohand, Samia; Desjardins, Roxane; Guérin, Brigitte; Day, Robert

2015-01-01

The overexpression as well as the critical implication of the proprotein convertase PACE4 in prostate cancer progression has been previously reported and supported the development of peptide inhibitors. The multi-Leu peptide, a PACE4-specific inhibitor, was further generated and its capability to be uptaken by tumor xenograft was demonstrated with regard to its PACE4 expression status. To investigate whether the uptake of this inhibitor was directly dependent of PACE4 levels, uptake and efflux from cancer cells were evaluated and correlations were established with PACE4 contents on both wild type and PACE4-knockdown cell lines. PACE4-knockdown associated growth deficiencies were established on the knockdown HepG2, Huh7, and HT1080 cells as well as the antiproliferative effects of the multi-Leu peptide supporting the growth capabilities of PACE4 in cancer cells. PMID:26114115

Double heterozygous mutations Gln100Leu and His348Gln of the F7 gene in a patient with factor VII deficiency.

PubMed

Li, Min; Zheng, Fangxiu; Jin, Yanhui; Wang, Mingshan; Zhu, Liqing; Yang, Lihong

2013-03-01

A 25-year-old Chinese woman who had a history of easy bruising was admitted to hospital due to uncontrolled epistaxis. She showed factor VII activity level of 2% and factor VII antigen level of 4% of the normal value. We detected a novel missense mutation g.8355 A>T (p.Gln100Leu) in the second epidermal growth factor-like (EGF) domain and a g.11482 T>G (p.His348Gln) in the catalytic domain. Although the Gln100 residue is close to the junction of EGF-2 domain with the serine protease domain, we infer that the substitution of polar negatively charged Gln residue at the position 100 with introduction of nonpolar Leu residue may be likely to perturb proper folding, resulting in decreasing factor VII activity.

Economically motivated adulteration (EMA) of food: common characteristics of EMA incidents.

PubMed

Everstine, Karen; Spink, John; Kennedy, Shaun

2013-04-01

Economically motivated adulteration (EMA) of food, also known as food fraud, is the intentional adulteration of food for financial advantage. A common form of EMA, undeclared substitution with alternative ingredients, is usually a health concern because of allergen labeling requirements. As demonstrated by the nearly 300,000 illnesses in China from melamine adulteration of infant formula, EMA also has the potential to result in serious public health consequences. Furthermore, EMA incidents reveal gaps in quality assurance testing methodologies that could be exploited for intentional harm. In contrast to foodborne disease outbreaks, EMA incidents present a particular challenge to the food industry and regulators because they are deliberate acts that are intended to evade detection. Large-scale EMA incidents have been described in the scientific literature, but smaller incidents have been documented only in media sources. We reviewed journal articles and media reports of EMA since 1980. We identified 137 unique incidents in 11 food categories: fish and seafood (24 incidents), dairy products (15), fruit juices (12), oils and fats (12), grain products (11), honey and other natural sweeteners (10), spices and extracts (8), wine and other alcoholic beverages (7), infant formula (5), plant-based proteins (5), and other food products (28). We identified common characteristics among the incidents that may help us better evaluate and reduce the risk of EMA. These characteristics reflect the ways in which existing regulatory systems or testing methodologies were inadequate for detecting EMA and how novel detection methods and other deterrence strategies can be deployed. Prevention and detection of EMA cannot depend on traditional food safety strategies. Comprehensive food protection, as outlined by the Food Safety Modernization Act, will require innovative methods for detecting EMA and for targeting crucial resources toward the riskiest food products.

AGM2015: Antineutrino Global Map 2015

PubMed Central

Usman, S.M.; Jocher, G.R.; Dye, S.T.; McDonough, W.F.; Learned, J.G.

2015-01-01

Every second greater than 1025 antineutrinos radiate to space from Earth, shining like a faint antineutrino star. Underground antineutrino detectors have revealed the rapidly decaying fission products inside nuclear reactors, verified the long-lived radioactivity inside our planet, and informed sensitive experiments for probing fundamental physics. Mapping the anisotropic antineutrino flux and energy spectrum advance geoscience by defining the amount and distribution of radioactive power within Earth while critically evaluating competing compositional models of the planet. We present the Antineutrino Global Map 2015 (AGM2015), an experimentally informed model of Earth’s surface antineutrino flux over the 0 to 11 MeV energy spectrum, along with an assessment of systematic errors. The open source AGM2015 provides fundamental predictions for experiments, assists in strategic detector placement to determine neutrino mass hierarchy, and aids in identifying undeclared nuclear reactors. We use cosmochemically and seismologically informed models of the radiogenic lithosphere/mantle combined with the estimated antineutrino flux, as measured by KamLAND and Borexino, to determine the Earth’s total antineutrino luminosity at . We find a dominant flux of geo-neutrinos, predict sub-equal crust and mantle contributions, with ~1% of the total flux from man-made nuclear reactors. PMID:26323507

AGM2015: Antineutrino Global Map 2015.

PubMed

Usman, S M; Jocher, G R; Dye, S T; McDonough, W F; Learned, J G

2015-09-01

Every second greater than 10(25) antineutrinos radiate to space from Earth, shining like a faint antineutrino star. Underground antineutrino detectors have revealed the rapidly decaying fission products inside nuclear reactors, verified the long-lived radioactivity inside our planet, and informed sensitive experiments for probing fundamental physics. Mapping the anisotropic antineutrino flux and energy spectrum advance geoscience by defining the amount and distribution of radioactive power within Earth while critically evaluating competing compositional models of the planet. We present the Antineutrino Global Map 2015 (AGM2015), an experimentally informed model of Earth's surface antineutrino flux over the 0 to 11 MeV energy spectrum, along with an assessment of systematic errors. The open source AGM2015 provides fundamental predictions for experiments, assists in strategic detector placement to determine neutrino mass hierarchy, and aids in identifying undeclared nuclear reactors. We use cosmochemically and seismologically informed models of the radiogenic lithosphere/mantle combined with the estimated antineutrino flux, as measured by KamLAND and Borexino, to determine the Earth's total antineutrino luminosity at . We find a dominant flux of geo-neutrinos, predict sub-equal crust and mantle contributions, with ~1% of the total flux from man-made nuclear reactors.

Proliferation resistance of small modular reactors fuels

DOE Office of Scientific and Technical Information (OSTI.GOV)

Polidoro, F.; Parozzi, F.; Fassnacht, F.

2013-07-01

In this paper the proliferation resistance of different types of Small Modular Reactors (SMRs) has been examined and classified with criteria available in the literature. In the first part of the study, the level of proliferation attractiveness of traditional low-enriched UO{sub 2} and MOX fuels to be used in SMRs based on pressurized water technology has been analyzed. On the basis of numerical simulations both cores show significant proliferation risks. Although the MOX core is less proliferation prone in comparison to the UO{sub 2} core, it still can be highly attractive for diversion or undeclared production of nuclear material. Inmore » the second part of the paper, calculations to assess the proliferation attractiveness of fuel in typical small sodium cooled fast reactor show that proliferation risks from spent fuel cannot be neglected. The core contains a highly attractive plutonium composition during the whole life cycle. Despite some aspects of the design like the sealed core that enables easy detection of unauthorized withdrawal of fissile material and enhances proliferation resistance, in case of open Non-Proliferation Treaty break-out, weapon-grade plutonium in sufficient quantities could be extracted from the reactor core.« less

Application of Reactor Antineutrinos: Neutrinos for Peace

NASA Astrophysics Data System (ADS)

Suekane, F.

2013-02-01

In nuclear reactors, 239Pu are produced along with burn-up of nuclear fuel. 239Pu is subject of safeguard controls since it is an explosive component of nuclear weapon. International Atomic Energy Agency (IAEA) is watching undeclared operation of reactors to prevent illegal production and removal of 239Pu. In operating reactors, a huge numbers of anti electron neutrinos (ν) are produced. Neutrino flux is approximately proportional to the operating power of reactor in short term and long term decrease of the neutrino flux per thermal power is proportional to the amount of 239Pu produced. Thus rector ν's carry direct and real time information useful for the safeguard purposes. Since ν can not be hidden, it could be an ideal medium to monitor the reactor operation. IAEA seeks for novel technologies which enhance their ability and reactor neutrino monitoring is listed as one of such candidates. Currently neutrino physicists are performing R&D of small reactor neutrino detectors to use specifically for the safeguard use in response to the IAEA interest. In this proceedings of the neutrino2012 conference, possibilities of such reactor neutrinos application and current world-wide R&D status are described.

Do We Need Plant Food Supplements? A Critical Examination of Quality, Safety, Efficacy, and Necessity for a New Regulatory Framework.

PubMed

Abdel-Tawab, Mona

2018-04-01

Given the expanding market of plant food supplements (PFSs) not undergoing any pre-marketing authorization, the overall quality, safety and efficacy of PFSs were subjected to a critical examination. Although many high-quality PFSs exist on the legal market, quality concerns are in general justified. Besides economic adulteration, active ingredients dramatically differing from label claims and among products were reported in several studies. In addition, PFSs sold via the Internet may be intentionally adulterated with undeclared prescription drugs. Compared to PFSs with only one single herb, PFSs containing herbal mixtures were more involved in moderate and severe clinical courses. Although prohibited by regulation, misleading labels on PFSs are common. Above all, only vague evidence for the efficacy of PFSs exists. Notwithstanding the unproven efficacy and insufficient safety assessment, PFSs represent a relevant source for consumers to get access to herbal preparations in the United States and meanwhile also in Europe, as launching of licensed/registered European herbal medicinal products (HMPs) has steadily decreased. However, being non-vitamin, non-mineral products, PFSs are neither food nor drugs. In terms of protecting public health and providing the consumer with high-quality, effective, and safe PFSs, possibilities are shown how to deal with the many challenges of PFSs. Last but not least, suggestions are made for assigning PFSs a separate regulatory category being less regulated compared to HMPs but more strictly regulated compared to food laws including implementation of good manufacturing practices and a scientific pre-marketing review process by an expert commission. Georg Thieme Verlag KG Stuttgart · New York.

Did the tobacco industry inflate estimates of illicit cigarette consumption in Asia? An empirical analysis.

PubMed

Chen, Jing; McGhee, Sarah M; Townsend, Joy; Lam, Tai Hing; Hedley, Anthony J

2015-06-01

Estimates of illicit cigarette consumption are limited and the data obtained from studies funded by the tobacco industry have a tendency to inflate them. This study aimed to validate an industry-funded estimate of 35.9% for Hong Kong using a framework taken from an industry-funded report, but with more transparent data sources. Illicit cigarette consumption was estimated as the difference between total cigarette consumption and the sum of legal domestic sales and legal personal imports (duty-free consumption). Reliable data from government reports and scientifically valid routine sources were used to estimate the total cigarette consumption by Hong Kong smokers and legal domestic sales in Hong Kong. Consumption by visitors and legal duty-free consumption by Hong Kong passengers were estimated under three scenarios for the assumptions to examine the uncertainty around the estimate. A two-way sensitivity analysis was conducted using different levels of possible undeclared smoking and under-reporting of self-reported daily consumption. Illicit cigarette consumption was estimated to be about 8.2-15.4% of the total cigarette consumption in Hong Kong in 2012 with a midpoint estimate of 11.9%, as compared with the industry-funded estimate of 35.9% of cigarette consumption. The industry-funded estimate was inflated by 133-337% of the probable true value. Only with significant levels of under-reporting of daily cigarette consumption and undeclared smoking could we approximate the value reported in the industry-funded study. The industry-funded estimate inflates the likely levels of illicit cigarette consumption. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

Undeclared exposure to St. John's Wort in hospitalized patients

PubMed Central

Martin-Facklam, Meret; Rieger, Karin; Riedel, Klaus-Dieter; Burhenne, Jürgen; Walter-Sack, Ingeborg; Haefeli, Walter E

2004-01-01

Aim The herbal medicine St. John's Wort (SJW) causes substantial decreases in the plasma concentrations of a range of co-administered drugs. Therefore, we evaluated the extent of systemic exposure to hyperforin and hypericin, two of the main constituents of SJW, in patients on admission and during hospital stay, and compared the results with known use of SJW as documented in the drug chart and detected in additional interviews. Methods One hundred and fifty patients aged ≥ 18 years and admitted, between August 2000 and February 2002, to an internal medicine ward of a large German university hospital were included. Hyperforin and hypericin was determined in plasma by a sensitive liquid chromotography/mass spectometry (LC/MS/MS) method. To assess undeclared use of SJW the data were compared to information obtained from drug charts and from up to three interviews that had a particular focus on intake of herbal medicines and self-medication during hospitalization. Results Hyperforin was detected in 12 patients (plasma concentration on the first day of hospitalization = 12–100 ng ml−1 in five patients and <3 ng ml−1 in seven), and hypericin in five patients (0.5–4.3 ng ml−1). Nine patients (6%) were taking/had taken SJW without the knowledge of the medical team and the pharmacist, who conducted the additional interviews, and 11 (7.3%) were taking/had taken SJW without the knowledge of the medical team alone. Seven of these patients were treated concurrently with drugs that can interact with SJW. Conclusions Unrecognized use of SJW is frequent and may have an important influence on the effectiveness and safety of drug therapy during hospital stay. PMID:15373938

Technetium-99 and strontium-90: Abundance determination at ultratrace sensitivity by AMS as signatures of undeclared nuclear reprocessing activity

DOE Office of Scientific and Technical Information (OSTI.GOV)

McAninch, J.E.; Proctor, I.D.

1995-03-01

The purpose of this White Paper is to examine the use of the ultratrace technique Accelerator Mass Spectrometry (AMS) to lower detection limits for {sup 99}Tc and {sup 90}Sr, and to examine the utility of these isotopes as signatures of a convert reprocessing facility. The International Atomic Energy Agency (IAEA) has committed to improving the effectiveness of the IAEA Safeguards System. This is in some degree a result of the discovery in 1991 of an undeclared Iraqi EMIS program. Recommendations from the March 1993 Consultants Group Meeting have resulted in several studies and follow on field trials to identify environmentalmore » signatures from covert nuclear fuel reprocessing activity. In particular, the April, 1993 reports of the Standing Advisory Group on Safeguards Implementation (SAGSI) identified the long-lived radioisotopes Technetium-99 and strontium-90 as two reliable signatures of fuel reprocessing activity. This report also suggested pathways in the chemical processing of irradiated fuel where these elements would be volatilized and potentially released in amounts detectable with ultratrace sensitivity techniques. Based on measured {sup 99}Tc background levels compiled from a variety of sources, it is estimated that AMS can provide 10% measurements of environmental levels of {sup 99}Tc in a few minutes using modestly sized samples: a few grams for soils, plants, or animal tissues; one to several liters for rain or seawater samples; and tens to hundreds of cubic meters for air sampling. Small sample sizes and high sample throughput result in significant increases in feasibility, cost effectiveness, and quality of data for a regional monitoring program. Similar results are expected for {sup 90}Sr.« less

L-leucine, beta-hydroxy-beta-methylbutyric acid (HMB) and creatine monohydrate prevent myostatin-induced Akirin-1/Mighty mRNA down-regulation and myotube atrophy.

PubMed

Mobley, Christopher Brooks; Fox, Carlton D; Ferguson, Brian S; Amin, Rajesh H; Dalbo, Vincent J; Baier, Shawn; Rathmacher, John A; Wilson, Jacob M; Roberts, Michael D

2014-01-01

The purpose of this study was to examine if L-leucine (Leu), β-hydroxy-β-methylbutyrate (HMB), or creatine monohydrate (Crea) prevented potential atrophic effects of myostatin (MSTN) on differentiated C2C12 myotubes. After four days of differentiation, myotubes were treated with MSTN (10 ng/ml) for two additional days and four treatment groups were studied: 1) 3x per day 10 mM Leu, 2) 3x per day 10 mM HMB, 3) 3x per day 10 mM Crea, 4) DM only. Myotubes treated with DM without MSTN were analyzed as the control condition (DM/CTL). Following treatment, cells were analyzed for total protein, DNA content, RNA content, muscle protein synthesis (MPS, SUnSET method), and fiber diameter. Separate batch treatments were analyzed for mRNA expression patterns of myostatin-related genes (Akirin-1/Mighty, Notch-1, Ski, MyoD) as well as atrogenes (MuRF-1, and MAFbx/Atrogin-1). MSTN decreased fiber diameter approximately 30% compared to DM/CTL myotubes (p < 0.001). Leu, HMB and Crea prevented MSTN-induced atrophy. MSTN did not decrease MPS levels compared to DM/CTL myotubes, but MSTN treatment decreased the mRNA expression of Akirin-1/Mighty by 27% (p < 0.001) and MyoD by 26% (p < 0.01) compared to DM/CTL myotubes. shRNA experiments confirmed that Mighty mRNA knockdown reduced myotube size, linking MSTN treatment to atrophy independent of MPS. Remarkably, MSTN + Leu and MSTN + HMB myotubes had similar Akirin-1/Mighty and MyoD mRNA levels compared to DM/CTL myotubes. Furthermore, MSTN + Crea myotubes exhibited a 36% (p < 0.05) and 86% (p < 0.001) increase in Akirin-1/Mighty mRNA compared to DM/CTL and MSTN-only treated myotubes, respectively. Leu, HMB and Crea may reduce MSTN-induced muscle fiber atrophy by influencing Akirin-1/Mighty mRNA expression patterns. Future studies are needed to examine if Leu, HMB and Crea independently or synergistically affect Akirin-1/Mighty expression, and how Akirin-1/Mighty expression mechanistically relates to skeletal muscle hypertrophy in vivo.

L-leucine, beta-hydroxy-beta-methylbutyric acid (HMB) and creatine monohydrate prevent myostatin-induced Akirin-1/Mighty mRNA down-regulation and myotube atrophy

PubMed Central

2014-01-01

Background The purpose of this study was to examine if L-leucine (Leu), β-hydroxy-β-methylbutyrate (HMB), or creatine monohydrate (Crea) prevented potential atrophic effects of myostatin (MSTN) on differentiated C2C12 myotubes. Methods After four days of differentiation, myotubes were treated with MSTN (10 ng/ml) for two additional days and four treatment groups were studied: 1) 3x per day 10 mM Leu, 2) 3x per day 10 mM HMB, 3) 3x per day 10 mM Crea, 4) DM only. Myotubes treated with DM without MSTN were analyzed as the control condition (DM/CTL). Following treatment, cells were analyzed for total protein, DNA content, RNA content, muscle protein synthesis (MPS, SUnSET method), and fiber diameter. Separate batch treatments were analyzed for mRNA expression patterns of myostatin-related genes (Akirin-1/Mighty, Notch-1, Ski, MyoD) as well as atrogenes (MuRF-1, and MAFbx/Atrogin-1). Results MSTN decreased fiber diameter approximately 30% compared to DM/CTL myotubes (p < 0.001). Leu, HMB and Crea prevented MSTN-induced atrophy. MSTN did not decrease MPS levels compared to DM/CTL myotubes, but MSTN treatment decreased the mRNA expression of Akirin-1/Mighty by 27% (p < 0.001) and MyoD by 26% (p < 0.01) compared to DM/CTL myotubes. shRNA experiments confirmed that Mighty mRNA knockdown reduced myotube size, linking MSTN treatment to atrophy independent of MPS. Remarkably, MSTN + Leu and MSTN + HMB myotubes had similar Akirin-1/Mighty and MyoD mRNA levels compared to DM/CTL myotubes. Furthermore, MSTN + Crea myotubes exhibited a 36% (p < 0.05) and 86% (p < 0.001) increase in Akirin-1/Mighty mRNA compared to DM/CTL and MSTN-only treated myotubes, respectively. Conclusions Leu, HMB and Crea may reduce MSTN-induced muscle fiber atrophy by influencing Akirin-1/Mighty mRNA expression patterns. Future studies are needed to examine if Leu, HMB and Crea independently or synergistically affect Akirin-1/Mighty expression, and how Akirin-1/Mighty expression mechanistically relates to skeletal muscle hypertrophy in vivo. PMID:25132809

Pathophysiological roles of aldo-keto reductases (AKR1C1 and AKR1C3) in development of cisplatin resistance in human colon cancers.

PubMed

Matsunaga, Toshiyuki; Hojo, Aki; Yamane, Yumi; Endo, Satoshi; El-Kabbani, Ossama; Hara, Akira

2013-02-25

Cisplatin (cis-diamminedichloroplatinum, CDDP) is widely used for treatment of patients with solid tumors formed in various organs including the lung, prostate and cervix, but is much less sensitive in colon and breast cancers. One major factor implicated in the ineffectiveness has been suggested to be acquisition of the CDDP resistance. Here, we established the CDDP-resistant phenotypes of human colon HCT15 cells by continuously exposing them to incremental concentrations of the drug, and monitored expressions of aldo-keto reductases (AKRs) 1A1, 1B1, 1B10, 1C1, 1C2 and 1C3. Among the six AKRs, AKR1C1 and AKR1C3 are highly induced with the CDDP resistance. The resistance lowered the sensitivity toward cellular damages evoked by oxidative stress-derived aldehydes, 4-hydroxy-2-nonenal and 4-oxo-2-nonenal that are detoxified by AKR1C1 and AKR1C3. Overexpression of AKR1C1 or AKR1C3 in the parental HCT15 cells mitigated the cytotoxicity of the aldehydes and CDDP. Knockdown of both AKR1C1 and AKR1C3 in the resistant cells or treatment of the cells with specific inhibitors of the AKRs increased the sensitivity to CDDP toxicity. Thus, the two AKRs participate in the mechanism underlying the CDDP resistance probably via detoxification of the aldehydes resulting from enhanced oxidative stress. The resistant cells also showed an enhancement in proteolytic activity of proteasome accompanied by overexpression of its catalytic subunits (PSMβ9 and PSMβ10). Pretreatment of the resistant cells with a potent proteasome inhibitor Z-Leu-Leu-Leu-al augmented the CDDP sensitization elicited by the AKR inhibitors. Additionally, the treatment of the cells with Z-Leu-Leu-Leu-al and the AKR inhibitors induced the expressions of the two AKRs and proteasome subunits. Collectively, these results suggest the involvement of up-regulated AKR1C1, AKR1C3 and proteasome in CDDP resistance of colon cancers and support a chemotherapeutic role for their inhibitors. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

Mass Spectrometric Assignment of Leu/Ile in Neuropeptides From Single Neurohemal Organ Preparations of Insets

DTIC Science & Technology

2005-01-01

spectrometry has been applied for the first time on an insect/arthropod target, focusing on PVK/CAP2b neuropeptides in the housefly Musca domestica and...critical physiological processes in insects. The unnatural Ile analog is 4.5 times more active than the native Leu sequence in a housefly Malpighian...periviscerokinin/cardioacceleratory peptide 2b) neuropeptides from single neurohemal organ preparations of adults of the housefly Musca domestica and flesh fly

Quantifying the relative contributions of different solute carriers to aggregate substrate transport

PubMed Central

Taslimifar, Mehdi; Oparija, Lalita; Verrey, Francois; Kurtcuoglu, Vartan; Olgac, Ufuk; Makrides, Victoria

2017-01-01

Determining the contributions of different transporter species to overall cellular transport is fundamental for understanding the physiological regulation of solutes. We calculated the relative activities of Solute Carrier (SLC) transporters using the Michaelis-Menten equation and global fitting to estimate the normalized maximum transport rate for each transporter (Vmax). Data input were the normalized measured uptake of the essential neutral amino acid (AA) L-leucine (Leu) from concentration-dependence assays performed using Xenopus laevis oocytes. Our methodology was verified by calculating Leu and L-phenylalanine (Phe) data in the presence of competitive substrates and/or inhibitors. Among 9 potentially expressed endogenous X. laevis oocyte Leu transporter species, activities of only the uniporters SLC43A2/LAT4 (and/or SLC43A1/LAT3) and the sodium symporter SLC6A19/B0AT1 were required to account for total uptake. Furthermore, Leu and Phe uptake by heterologously expressed human SLC6A14/ATB0,+ and SLC43A2/LAT4 was accurately calculated. This versatile systems biology approach is useful for analyses where the kinetics of each active protein species can be represented by the Hill equation. Furthermore, its applicable even in the absence of protein expression data. It could potentially be applied, for example, to quantify drug transporter activities in target cells to improve specificity. PMID:28091567

The Cytoplasmic Permeation Pathway of Neurotransmitter Transporters†

PubMed Central

Rudnick, Gary

2011-01-01

Ion-coupled solute transporters are responsible for transporting nutrients, ions and signaling molecules across a variety of biological membranes. Recent high-resolution crystal structures of several transporters from protein families that were previously thought to be unrelated show common structural features indicating a large structural family representing transporters from all kingdoms of life. This review describes studies that led to an understanding of the conformational changes required for solute transport in this family. The first structure in this family showed the bacterial amino acid transporter LeuT, which is homologous to neurotransmitter transporters, in an extracellularly-oriented conformation with a molecule of leucine occluded at the substrate site. Studies with the mammalian serotonin transporter identified positions, buried in the LeuT structure, that defined a potential pathway leading from the cytoplasm to the substrate binding site. Modeling studies utilized an inverted structural repeat within the LeuT crystal structure to predict the conformation of LeuT in which the cytoplasmic permeation pathway, consisting of positions identified in SERT, was open for substrate diffusion to the cytoplasm. From the difference between the model and the crystal structures, a simple “rocking bundle” mechanism was proposed, in which a 4-helix bundle changed its orientation with respect to the rest of the protein to close the extracellular pathway and open the cytoplasmic one. Subsequent crystal structures from structurally related proteins provide evidence supporting this model for transport. PMID:21774491

Development of buccal drug delivery systems based on a thiolated polymer.

PubMed

Langoth, Nina; Kalbe, Jochen; Bernkop-Schnürch, Andreas

2003-02-18

The purpose of the present study was to investigate the benefit of thiolated polymers (thiomers) for the development of buccal drug delivery systems. L-Cysteine was thereby covalently attached to polycarbophil (PCP) mediated by a carbodiimide. The resulting conjugate displayed 140.5+/-8.4 microM thiol groups per gram polymer. Disintegration studies were carried out with tablets based on unmodified polymer and conjugated polymer, respectively. Due to the formation of disulfide bonds within the thiolated polymer, the stability of matrix-tablets based on this polymer was strongly improved. Additionally tensile studies were carried out, which were in good correlation with further results obtained by mucoadhesion studies, using the rotating cylinder method. These results showed that tablets based on thiolated PCP remained attached on freshly excised porcine mucosa 1.8 times longer than the corresponding control. Moreover, the enzyme inhibitory properties of polymers were evaluated as well. Thiolated PCP increased the stability of the synthetic substrate for aminopeptidase N-leu-p-nitroanilide (N-leu-pNA) and the model drug leucin-enkephalin (leu-enkephalin) against enzymatic degradation on buccal mucosa. Due to the use of thiolated polymers also a controlled drug release for leu-enkephalin was guaranteed over a time period for more than 24 h. Results of the present studies suggest that thiolated polymers represent a very useful tool for buccal delivery of peptide drugs.

Synthesis and antibacterial activity of new peptides from Alfalfa RuBisCO protein hydrolysates and mode of action via a membrane damage mechanism against Listeria innocua.

PubMed

Kobbi, Sabrine; Nedjar, Naima; Chihib, Nourdine; Balti, Rafik; Chevalier, Mickael; Silvain, Amandine; Chaabouni, Semia; Dhulster, Pascal; Bougatef, Ali

2018-02-01

In this work we evaluated the mode of action of six new synthesized peptides (Met-Asp-Asn; Glu-leu-Ala-Ala-Ala-Cys; Leu-Arg-Asp-Asp-Phe; Gly-Asn-Ala-Pro-Gly-Ala-Val-Ala; Ala-Leu-Arg-Met-Ser-Gly and Arg-Asp-Arg-Phe-Leu), previously identified, from the most active peptide fractions of RuBisCO peptic hydrolysate against Listeria innocua via a membrane damage mechanism. Antibacterial effect and the minimum inhibitory concentrations (MIC) of these peptides were evaluated against six strains and their hemolytic activities towards bovine erythrocytes were determined. Prediction of the secondary structure of peptides indicated that these new antibacterial peptides are characterized by a short peptide chains (3-8 amino acid) and a random coli structure. Moreover, it was observed that one key characteristic of antibacterial peptides is the presence of specific amino acids such as cysteine, glycine, arginine and aspartic acid. In addition the determination of the extracellular potassium concentration revealed that treatment with pure RuBisCO peptides could cause morphological changes of L. innocua and destruction of the cell integrity via irreversible membrane damage. The results could provide information for investigating the antibacterial model of antibacterial peptides derived from RuBisCO protein hydrolysates. Copyright © 2017 Elsevier Ltd. All rights reserved.

Structural, Functional, and Clinical Characterization of a Novel PTPN11 Mutation Cluster Underlying Noonan Syndrome.

PubMed

Pannone, Luca; Bocchinfuso, Gianfranco; Flex, Elisabetta; Rossi, Cesare; Baldassarre, Giuseppina; Lissewski, Christina; Pantaleoni, Francesca; Consoli, Federica; Lepri, Francesca; Magliozzi, Monia; Anselmi, Massimiliano; Delle Vigne, Silvia; Sorge, Giovanni; Karaer, Kadri; Cuturilo, Goran; Sartorio, Alessandro; Tinschert, Sigrid; Accadia, Maria; Digilio, Maria C; Zampino, Giuseppe; De Luca, Alessandro; Cavé, Hélène; Zenker, Martin; Gelb, Bruce D; Dallapiccola, Bruno; Stella, Lorenzo; Ferrero, Giovanni B; Martinelli, Simone; Tartaglia, Marco

2017-04-01

Germline mutations in PTPN11, the gene encoding the Src-homology 2 (SH2) domain-containing protein tyrosine phosphatase (SHP2), cause Noonan syndrome (NS), a relatively common, clinically variable, multisystem disorder. Here, we report on the identification of five different PTPN11 missense changes affecting residues Leu 261 , Leu 262 , and Arg 265 in 16 unrelated individuals with clinical diagnosis of NS or with features suggestive for this disorder, specifying a novel disease-causing mutation cluster. Expression of the mutant proteins in HEK293T cells documented their activating role on MAPK signaling. Structural data predicted a gain-of-function role of substitutions at residues Leu 262 and Arg 265 exerted by disruption of the N-SH2/PTP autoinhibitory interaction. Molecular dynamics simulations suggested a more complex behavior for changes affecting Leu 261 , with possible impact on SHP2's catalytic activity/selectivity and proper interaction of the PTP domain with the regulatory SH2 domains. Consistent with that, biochemical data indicated that substitutions at codons 262 and 265 increased the catalytic activity of the phosphatase, while those affecting codon 261 were only moderately activating but impacted substrate specificity. Remarkably, these mutations underlie a relatively mild form of NS characterized by low prevalence of cardiac defects, short stature, and cognitive and behavioral issues, as well as less evident typical facial features. © 2017 WILEY PERIODICALS, INC.

BMI, RQ, Diabetes, and Sex Affect the Relationships Between Amino Acids and Clamp Measures of Insulin Action in Humans

PubMed Central

Thalacker-Mercer, Anna E.; Ingram, Katherine H.; Guo, Fangjian; Ilkayeva, Olga; Newgard, Christopher B.; Garvey, W. Timothy

2014-01-01

Previous studies have used indirect measures of insulin sensitivity to link circulating amino acids with insulin resistance and identify potential biomarkers of diabetes risk. Using direct measures (i.e., hyperinsulinemic-euglycemic clamps), we examined the relationships between the metabolomic amino acid profile and insulin action (i.e., glucose disposal rate [GDR]). Relationships between GDR and serum amino acids were determined among insulin-sensitive, insulin-resistant, and type 2 diabetic (T2DM) individuals. In all subjects, glycine (Gly) had the strongest correlation with GDR (positive association), followed by leucine/isoleucine (Leu/Ile) (negative association). These relationships were dramatically influenced by BMI, the resting respiratory quotient (RQ), T2DM, and sex. Gly had a strong positive correlation with GDR regardless of BMI, RQ, or sex but became nonsignificant in T2DM. In contrast, Leu/Ile was negatively associated with GDR in nonobese and T2DM subjects. Increased resting fat metabolism (i.e., low RQ) and obesity were observed to independently promote and negate the association between Leu/Ile and insulin resistance, respectively. Additionally, the relationship between Leu/Ile and GDR was magnified in T2DM males. Future studies are needed to determine whether Gly has a mechanistic role in glucose homeostasis and whether dietary Gly enrichment may be an effective intervention in diseases characterized by insulin resistance. PMID:24130332

Metabolomics Analysis Reveals Specific Novel Tetrapeptide and Potential Anti-Inflammatory Metabolites in Pathogenic Aspergillus species.

PubMed

Lee, Kim-Chung; Tam, Emily W T; Lo, Ka-Ching; Tsang, Alan K L; Lau, Candy C Y; To, Kelvin K W; Chan, Jasper F W; Lam, Ching-Wan; Yuen, Kwok-Yung; Lau, Susanna K P; Woo, Patrick C Y

2015-06-17

Infections related to Aspergillus species have emerged to become an important focus in infectious diseases, as a result of the increasing use of immunosuppressive agents and high fatality associated with invasive aspergillosis. However, laboratory diagnosis of Aspergillus infections remains difficult. In this study, by comparing the metabolomic profiles of the culture supernatants of 30 strains of six pathogenic Aspergillus species (A. fumigatus, A. flavus, A. niger, A. terreus, A. nomius and A. tamarii) and 31 strains of 10 non-Aspergillus fungi, eight compounds present in all strains of the six Aspergillus species but not in any strain of the non-Aspergillus fungi were observed. One of the eight compounds, Leu-Glu-Leu-Glu, is a novel tetrapeptide and represents the first linear tetrapeptide observed in Aspergillus species, which we propose to be named aspergitide. Two other closely related Aspergillus-specific compounds, hydroxy-(sulfooxy)benzoic acid and (sulfooxy)benzoic acid, may possess anti-inflammatory properties, as 2-(sulfooxy)benzoic acid possesses a structure similar to those of aspirin [2-(acetoxy)benzoic acid] and salicylic acid (2-hydroxybenzoic acid). Further studies to examine the potentials of these Aspergillus-specific compounds for laboratory diagnosis of aspergillosis are warranted and further experiments will reveal whether Leu-Glu-Leu-Glu, hydroxy-(sulfooxy)benzoic acid and (sulfooxy)benzoic acid are virulent factors of the pathogenic Aspergillus species.

Analysis of Manganese Superoxide Dismutase and Glutathione Peroxidase 1 Gene Polymorphisms in Vitiligo.

PubMed

Seçkin, Havva Yıldız; Kalkan, Göknur; Bütün, İlknur; Akbaş, Ali; Baş, Yalçın; Karakuş, Nevin; Benli, İsmail

2016-08-01

Vitiligo is a hereditary/acquired progressive pigmentation disorder characterized by discoloration of skin as a result of melanocyte dysfunction. Recent studies have proposed that oxidant/antioxidant status plays an important role in vitiligo pathogenesis because of the toxic effects on melanocytes. In this study, we aimed to investigate possible associations of MnSOD Ala-9Val and GPx1 Pro198Leu polymorphisms with vitiligo with in Turkish population. The study group consists of 57 patients with vitiligo and 69 healthy controls. Genotyping is performed to identify MnSOD Ala-9Val and GPx1 Pro198Leu polymorphisms. The method used for genotyping was based on the PCR amplification and detection of polymorphisms by hybridization probes labeled with fluorescent dyes. Both the genotype and allele frequencies of MnSOD Ala-9Val (p = 0.817 and p = 0.553, respectively) and GPx1 Pro198Leu polymorphisms (p = 0.422 and p = 0.673, respectively) were not significantly different between vitiligo patients and the control group. Although no significant difference was found, this is the first report investigating the possible associations between the MnSOD Ala-9Val and GPx1 Pro198Leu polymorphisms in Turkish population. Further studies with large populations will be able to clarify the association better.

IL1R2, CCR2, and CXCR4 May Form Heteroreceptor Complexes with NMDAR and D2R: Relevance for Schizophrenia

PubMed Central

Borroto-Escuela, Dasiel O.; Tarakanov, Alexander O.; Bechter, Karl; Fuxe, Kjell

2017-01-01

The mild neuroinflammation hypothesis of schizophrenia was introduced by Bechter in 2001. It has been hypothesized that a hypofunction of glutamatergic signaling via N-methyl-D-aspartate receptors (NMDARs) and hyperactivation of dopamine D2 receptors play a role in schizophrenia. The triplet puzzle theory states that sets of triplet amino acid homologies guide two different receptors toward each other and contributes to the formation of a receptor heteromer. It is, therefore, proposed that putative NMDAR-C-C chemokine receptor type 2 (CCR2), NMDAR-C-X-C chemokine receptor type 4 (CXCR4), and NMDAR- interleukin 1 receptor type II (IL1R2) heteromers can be formed in the neuronal networks in mild neuroinflammation due to demonstration of Gly-Leu-Leu (GLL), Val-Ser-Thr (VST), and/or Ser-Val-Ser (SVS) amino acid homologies between these receptor protomers. This molecular process may underlie the ability to produce symptoms of schizophrenia in mild neuroinflammation. In this state, volume transmission (VT) is increased involving increased extracellular vesicle-mediated VT from microglia and astroglia. These vesicles may contain CCR2, CXCR4, and/or IL1R2 as well as their ligands and upon internalization by endocytic pathways into neurons can form heteroreceptor complexes with NMDAR in the plasma membrane with pathological allosteric receptor–receptor interactions involving increased internalization and reduced NMDAR signaling. The triplet puzzle theory also suggests the formation of putative D2R-CCR2, D2R-CXCR4, and D2R-IL1R2 heteromers in mild neuroinflammation in view of their demonstrated sets of Leu-Tyr-Ser (LYS), Leu-Pro-Phe (LPF), and/or Ser-Leu-Ala (SLA) triplet homologies. These D2R heteroreceptor complexes may also contribute to schizophrenia-like symptoms in mild neuroinflammation by enhancing D2R protomer function. PMID:28261115

Introduction of water into the heme distal side by Leu65 mutations of an oxygen sensor, YddV, generates verdoheme and carbon monoxide, exerting the heme oxygenase reaction.

PubMed

Stranava, Martin; Martínková, Markéta; Stiborová, Marie; Man, Petr; Kitanishi, Kenichi; Muchová, Lucie; Vítek, Libor; Martínek, Václav; Shimizu, Toru

2014-11-01

The globin-coupled oxygen sensor, YddV, is a heme-based oxygen sensor diguanylate cyclase. Oxygen binding to the heme Fe(II) complex in the N-terminal sensor domain of this enzyme substantially enhances its diguanylate cyclase activity which is conducted in the C-terminal functional domain. Leu65 is located on the heme distal side and is important for keeping the stability of the heme Fe(II)-O2 complex by preventing the entry of the water molecule to the heme complex. In the present study, it was found that (i) Escherichia coli-overexpressed and purified L65N mutant of the isolated heme-bound domain of YddV (YddV-heme) contained the verdoheme iron complex and other modified heme complexes as determined by optical absorption spectroscopy and mass spectrometry; (ii) CO was generated in the reconstituted system composed of heme-bound L65N and NADPH:cytochrome P450 reductase as confirmed by gas chromatography; (iii) CO generation of heme-bound L65N in the reconstituted system was inhibited by superoxide dismutase and catalase. In a concordance with the result, the reactive oxygen species increased the CO generation; (iv) the E. coli cells overexpressing the L65N protein of YddV-heme also formed significant amounts of CO compared to the cells overexpressing the wild type protein; (v) generation of verdoheme and CO was also observed for other mutants at Leu65 as well, but to a lesser extent. Since Leu65 mutations are assumed to introduce the water molecule into the heme distal side of YddV-heme, it is suggested that the water molecule would significantly contribute to facilitating heme oxygenase reactions for the Leu65 mutants. Copyright © 2014 Elsevier Inc. All rights reserved.

SARS-CoV 3CL protease cleaves its C-terminal autoprocessing site by novel subsite cooperativity.

PubMed

Muramatsu, Tomonari; Takemoto, Chie; Kim, Yong-Tae; Wang, Hongfei; Nishii, Wataru; Terada, Takaho; Shirouzu, Mikako; Yokoyama, Shigeyuki

2016-11-15

The 3C-like protease (3CL pro ) of severe acute respiratory syndrome coronavirus (SARS-CoV) cleaves 11 sites in the polyproteins, including its own N- and C-terminal autoprocessing sites, by recognizing P4-P1 and P1'. In this study, we determined the crystal structure of 3CL pro with the C-terminal prosequence and the catalytic-site C145A mutation, in which the enzyme binds the C-terminal prosequence of another molecule. Surprisingly, Phe at the P3' position [Phe(P3')] is snugly accommodated in the S3' pocket. Mutations of Phe(P3') impaired the C-terminal autoprocessing, but did not affect N-terminal autoprocessing. This difference was ascribed to the P2 residue, Phe(P2) and Leu(P2), in the C- and N-terminal sites, as follows. The S3' subsite is formed by Phe(P2)-induced conformational changes of 3CL pro and the direct involvement of Phe(P2) itself. In contrast, the N-terminal prosequence with Leu(P2) does not cause such conformational changes for the S3' subsite formation. In fact, the mutation of Phe(P2) to Leu in the C-terminal autoprocessing site abolishes the dependence on Phe(P3'). These mechanisms explain why Phe is required at the P3' position when the P2 position is occupied by Phe rather than Leu, which reveals a type of subsite cooperativity. Moreover, the peptide consisting of P4-P1 with Leu(P2) inhibits protease activity, whereas that with Phe(P2) exhibits a much smaller inhibitory effect, because Phe(P3') is missing. Thus, this subsite cooperativity likely exists to avoid the autoinhibition of the enzyme by its mature C-terminal sequence, and to retain the efficient C-terminal autoprocessing by the use of Phe(P2).

International Atomic Energy Agency Safeguards: Challenge and response

NASA Astrophysics Data System (ADS)

Spector, Leonard S.

2017-11-01

This article provides a critical review of the nuclear accounting and inspection system of the International Atomic Energy Agency (IAEA), known as "IAEA safeguards." The article focuses on the multiple challenges the Agency confronts in verifying that all nuclear activities in the countries under its safeguards system are being pursued for exclusively peaceful purposes. The principal challenges noted are those posed by: undeclared facilities, the development of enrichment and reprocessing capabilities, illicit procurement activities, denial of inspector access, difficulties in verifying absence of weaponization activities, and difficulties in establishing that all nuclear-relevant activities in a state are peaceful. The article is in the form of annotated PowerPoint briefing slides.

Cyclo(dehydroala-L-Leu), an alpha-glucosidase inhibitor from Penicillium sp. F70614.

PubMed

Kwon, O S; Park, S H; Yun, B S; Pyun, Y R; Kim, C J

2000-09-01

A diketopiperazine (1) has been isolated from the culture broth of Penicillium sp. F70614 and its structure has been determined to be cyclo(dehydroala-L-Leu) by various spectroscopic analyses. This compound selectively inhibited yeast alpha-glucosidase and porcine intestinal alpha-glucosidase with IC50 values of 35 and 50 microg/ml, respectively. However, it did not show significant inhibitory effects against almond beta3-glucosidase, Aspergillus alpha-galactosidase, Escherichia coli beta-galactosidase and jack bean alpha-mannosidase.

Biochemical Characterization of VIM-39, a VIM-1-Like Metallo-β-Lactamase Variant from a Multidrug-Resistant Klebsiella pneumoniae Isolate from Greece.

PubMed

Papagiannitsis, Costas C; Pollini, Simona; De Luca, Filomena; Rossolini, Gian Maria; Docquier, Jean-Denis; Hrabák, Jaroslav

2015-12-01

VIM-39, a VIM-1-like metallo-β-lactamase variant (VIM-1 Thr33Ala His224Leu) was identified in a clinical isolate of Klebsiella pneumoniae belonging to sequence type 147. VIM-39 hydrolyzed ampicillin, cephalothin, and imipenem more efficiently than did VIM-1 and VIM-26 (a VIM-1 variant with the His224Leu substitution) because of higher turnover rates. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

Documentation and Analysis of IAEA (International Atomic Energy Agency) Safeguards Implementation at the Exxon Nuclear Fuel Fabrication Plant.

DTIC Science & Technology

1984-10-01

SAFEGUARDS AT SIMILAR FACILTTIES ASEA -ATOM LEU FUEL FABRICATION PLANT IN VASTERAS, SWEDEN..................B-1 APPENDIX C - EFFECTS OF NONMEASUREMENT ERRORS...second visit was to the ASEA -ATOM’s fuel fabrication plant in Vasteras, Sweden. The safeguards specialists for those plants were interviewed by R...Facilities, ASEA -ATOM LEU Fuel Fabrication Plant in Vasteras, Sweden, by V. Andersson of ASEA -ATOM, Vasteras, Sweden and R. Nilson of Exxon Nuclear

[Phenotypic and genotypic spectra of patients with glucose-6-phosphate dehydrogenase deficiency gene known pathogenic variants: a single-center study].

PubMed

Chen, X; Yang, L; Wang, H J; Wu, B B; Lu, Y L; Dong, X R; Zhou, W H

2018-05-02

Objective: To analyze the hotspots of known pathogenic disease-causing variants of glucose-6-phosphate dehydrogenase (G6PD) and the phenotype spectrum of neonatal patients with known pathogenic disease-causing variants of G6PD. Methods: The known pathogenic disease-causing variants of G6PD were collected from Human Gene Mutation Database. Screening was performed for these variants among the 7 966 cases (2 357 neonatal, 5 609 non-neonatal) in the database of sequencing at Molecular Diagnosis Center, Children's Hospital of Fudan University. All these samples were from patients suspected with genetic disorder. The database contained Whole Exon Sequencing data and Clinical Exon Sequencing data. We screened out the patients with known pathogenic disease-causing variants of G6PD, analyzed the hotspot of G6PD and the phenotype spectrum of neonatal patients with known pathogenic disease-causing variants of G6PD. Results: (1) Among the next generation sequencing data of the 7 966 samples, 86 samples (1.1%) were detected as positive for the known pathogenic disease-causing variants of G6PD (positive samples set). In the positive sample set, 51 patients (33 males, 18 females) were newborn babies. Forty-three patients (26 males, 17 females) had the enzyme activity data of G6PD. (2) Among the 86 samples, Arg463His, Arg459Leu, Leu342Phe, Val291Met were the leading 4 disease-causing variants found in 72 samples (84%). (3) Male neonatal patients with the same variants had the statistically significant differences in enzyme activity: among 13 patients with Arg463His, enzyme activity of 9 patients was ranked as grade Ⅲ, 1 case ranked as Ⅳ, 3 cases had no activity data;among 10 patients with Arg459Leu, enzyme activity of 4 patients was ranked as Ⅱ, 4 cases ranked as Ⅲ, 2 cases had no activity data;among 2 patients with His32Arg, enzyme activity of one patient was ranked as Ⅱ, another was Ⅲ. Male neonatal patients with the same mutation and enzyme activity also had the statistically significant differences in phenotype spectrum: among 9 patients with Arg463His and level Ⅲ enzyme activity, 6 presented hyperbilirubinemia, 2 met the criteria for exchange transfusion therapy, 2 showed hemolysis;among 4 patients with Arg459Leu and level Ⅱ enzyme activity, 3 presented hyperbilirubinemia;among 4 patients with Arg459Leu and level Ⅲ enzyme activity, 2 presented hyperbilirubinemia, 1 met the standard of exchange transfusion therapy;among 3 patients with Val291Met and level Ⅲ enzyme activity, 1 presented hyperbilirubinemia. Conclusions: Arg463His, Arg459Leu, Leu342Phe, Val291Met were the hotspots variants for the G6PD. Patients with the same G6PD variants and sex present different phenotype, patients with the same G6PD variants, sex and enzyme activity also present different phenotype .

Performance and Fabrication Status of TREAT LEU Conversion Conceptual Design Concepts

DOE Office of Scientific and Technical Information (OSTI.GOV)

IJ van Rooyen; SR Morrell; AE Wright

2014-10-01

Resumption of transient testing at the TREAT facility was approved in February 2014 to meet U.S. Department of Energy (DOE) objectives. The National Nuclear Security Administration’s Global Threat Reduction Initiative Convert Program is evaluating conversion of TREAT from its existing highly enriched uranium (HEU) core to a new core containing low enriched uranium (LEU). This paper describes briefly the initial pre-conceptual designs screening decisions with more detailed discussions on current feasibility, qualification and fabrication approaches. Feasible fabrication will be shown for a LEU fuel element assembly that can meet TREAT design, performance, and safety requirements. The statement of feasibility recognizesmore » that further development, analysis, and testing must be completed to refine the conceptual design. Engineering challenges such as cladding oxidation, high temperature material properties, and fuel block fabrication along with neutronics performance, will be highlighted. Preliminary engineering and supply chain evaluation provided confidence that the conceptual designs can be achieved.« less

Glutaric aciduria type 1 in Korea: report of two novel mutations.

PubMed

Park, June Dong; Lim, ByungChan; Kim, Ki Joong; Hwang, Yong Seung; Kim, Seung Ki; Kang, Seong-Ho; Cho, Sung Im; Park, Sung Sup; Lee, Joon Soo; Chae, Jong Hee

2010-06-01

Glutaric aciduria type I (GA I) is an autosomal recessive disorder caused by a deficiency of glutaryl-CoA dehydrogenase. Although over 400 patients confirmed as GA I have been reported, reports from the Asian population had contributed to the minor proportion. We recently diagnosed two cases of GA I confirmed with mutational analysis. Here, we present their rather atypical clinical presentations with genetic characteristics for the first time in Korea. Profound developmental delay from birth, association of hearing loss, and neurological improvement after surgical intervention, were considered to be different clinical features from most reported cases. One patient was a compound heterozygote for p.Ser139Leu and p.Asp220Tyr, and the other for p.Ser139Leu and Glu160X. The mutations of the two alleles (p.Asp220Tyr and p.Glu160X) were novel and reports of p.Ser139Leu were rare both in Western and other Asian populations. These might suggest different genetic spectrum of Korean GA I patients.

Glutaric Aciduria Type 1 in Korea: Report of Two Novel Mutations

PubMed Central

Park, June Dong; Lim, ByungChan; Kim, Ki Joong; Hwang, Yong Seung; Kim, Seung Ki; Kang, Seong-Ho; Cho, Sung Im; Park, Sung Sup; Lee, Joon Soo

2010-01-01

Glutaric aciduria type I (GA I) is an autosomal recessive disorder caused by a deficiency of glutaryl-CoA dehydrogenase. Although over 400 patients confirmed as GA I have been reported, reports from the Asian population had contributed to the minor proportion. We recently diagnosed two cases of GA I confirmed with mutational analysis. Here, we present their rather atypical clinical presentations with genetic characteristics for the first time in Korea. Profound developmental delay from birth, association of hearing loss, and neurological improvement after surgical intervention, were considered to be different clinical features from most reported cases. One patient was a compound heterozygote for p.Ser139Leu and p.Asp220Tyr, and the other for p.Ser139Leu and Glu160X. The mutations of the two alleles (p.Asp220Tyr and p.Glu160X) were novel and reports of p.Ser139Leu were rare both in Western and other Asian populations. These might suggest different genetic spectrum of Korean GA I patients. PMID:20514322

LANL Experience Rolling Zr-Clad LEU-10Mo Foils for AFIP-7

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hammon, Duncan L.; Clarke, Kester D.; Alexander, David J.

2015-05-29

The cleaning, canning, rolling and final trimming of Low Enriched Uranium-10 wt. pct. Molybdenum (LEU-10Mo) foils for ATR (Advanced Test Reactor) fuel plates to be used in the AFIP-7 (ATR Full Size Plate In Center Flux Trap Position) experiments are summarized. Six Zr-clad foils were produced from two LEU-10Mo castings supplied to Los Alamos National Laboratory (LANL) by Y-12 National Security Complex. Details of cleaning and canning procedures are provided. Hot- and cold-rolling results are presented, including rolling schedules, images of foils in-process, metallography and local compositions of regions of interest, and details of final foil dimensions and process yield.more » This report was compiled from the slides for the presentation of the same name given by Duncan Hammon on May 12, 2011 at the AFIP-7 Lessons Learned meeting in Salt Lake City, UT, with Los Alamos National Laboratory document number LA-UR 11-02898.« less

Design of ET(B) receptor agonists: NMR spectroscopic and conformational studies of ET7-21[Leu7, Aib11, Cys(Acm)15].

PubMed

Hewage, Chandralal M; Jiang, Lu; Parkinson, John A; Ramage, Robert; Sadler, Ian H

2002-03-01

In a previous report we have shown that the endothelin-B receptor-selective linear endothelin peptide, ET-1[Cys (Acm)1,15, Ala3, Leu7, Aib11], folds into an alpha-helical conformation in a methanol-d3/water co-solvent [Hewage et al. (1998) FEBS Lett., 425, 234-238]. To study the requirements for the structure-activity relationships, truncated analogues of this peptide were subjected to further studies. Here we report the solution conformation of ET7-21[Leu7, Aib11, Cys(Acm)15], in a methanol-d3/water co-solvent at pH 3.6, by NMR spectroscopic and molecular modelling studies. Further truncation of this short peptide results in it displaying poor agonist activity. The modelled structure shows that the peptide folds into an alpha-helical conformation between residues Lys9-His16, whereas the C-terminus prefers no fixed conformation. This truncated linear endothelin analogue is pivotal for designing endothelin-B receptor agonists.

A novel angiotensin-І converting enzyme (ACE) inhibitory peptide from gastrointestinal protease hydrolysate of silkworm pupa (Bombyx mori) protein: Biochemical characterization and molecular docking study.

PubMed

Wu, Qiongying; Jia, Junqiang; Yan, Hui; Du, Jinjuan; Gui, Zhongzheng

2015-06-01

Silkworm pupa (Bombyx mori) protein was hydrolyzed using gastrointestinal endopeptidases (pepsin, trypsin and α-chymotrypsin). Then, the hydrolysate was purified sequentially by ultrafiltration, gel filtration chromatography and RP-HPLC. A novel ACE inhibitory peptide, Ala-Ser-Leu, with the IC50 value of 102.15μM, was identified by IT-MS/MS. This is the first report of Ala-Ser-Leu from natural protein. Lineweaver-Burk plots suggest that the peptide is a competitive inhibitor against ACE. The molecular docking studies revealed that the ACE inhibition of Ala-Ser-Leu is mainly attributed to forming very strong hydrogen bonds with the S1 pocket (Ala354) and the S2 pocket (Gln281 and His353). The results indicate that silkworm pupa (B. mori) protein or its gastrointestinal protease hydrolysate could be used as a functional ingredient in auxiliary therapeutic foods against hypertension. Copyright © 2014 Elsevier Inc. All rights reserved.

Epitope mapping and immunological characterization of a major allergen TBa in tartary buckwheat.

PubMed

Ren, Xiaoxia; Zhang, Xin; Li, Yuying; Wang, Zhuanhua

2010-09-01

Predicted by an antigenic program, full-length tartary buckwheat allergen (TBa) is divided into six fragments: E1, E2, E12, E3, E4 and E34. Immunological assays revealed that E1 has the greatest binding activity to patients' serum IgE. Five mutants of E1 gene (L39R, L42R, L47R, V52R and L54R) were constructed using site-directed mutagenesis and each protein was expressed in Escherichia coli BL21. Following purification by Ni(2+) affinity chromatography, ELISA and dot-blot were performed for wild type E1 and its mutants using sera from buckwheat allergic patients and healthy controls. Mutants L42R, L47R, and L54R had weaker IgE binding activity to patient's sera than wild-type E1 implying that Leu42, Leu47, and Leu54 might be involved in the allergic activity of TBa.

Early-onset ocular ochronosis in a girl with alkaptonuria (AKU) and a novel mutation in homogentisate 1,2-dioxygenase (HGD).

PubMed

Gucev, Z S; Slaveska, N; Laban, N; Danilovski, D; Tasic, V; Pop-Jordanova, N; Zatkova, A

2011-01-01

Alkaptonuria (AKU) is a disorder of phenylalanine/tyrosine metabolism due to a defect in the enzyme homogentisate 1,2-dioxygenase (HGD). This recessive disease is caused by mutations in the HGD gene. We report a 14-year-old girl who was referred after presenting black urine. Careful examination revealed ochronosis of the conjunctiva. There was no affection of the cardiac valves. Elevated excretion of homogentisic acid in urine was found. Sequence analysis of the HGD gene from genomic DNA revealed that the patient is a compound heterozygote with a previously described mutation (c.473C>T, p.Pro158Leu), and a novel one (c.821C>T, p.Pro274Leu). Her mother is heterozygous for the novel mutation, while the brother is heterozygous for the previously described mutation. In summary, we describe an alkaptonuric patient with ocular ochronosis and a novel HGD mutation, c.821C>T, p.Pro274Leu.

Specific formation of negative ions from leucine and isoleucine molecules

NASA Astrophysics Data System (ADS)

Papp, Peter; Shchukin, Pavel; Matejčík, Štefan

2010-01-01

Dissociative electron attachment (DEA) to gas phase leucine (Leu) and isoleucine (Ile) molecules was studied using experimental and quantum-chemical methods. The relative partial cross sections for DEA have been measured using crossed electron/molecular beams technique. Supporting ab initio calculations of the structure, energies of neutral molecules, fragments, and negative ions have been carried out at G3MP2 and B3LYP levels in order to interpret the experimental data. Leu and Ile exhibit several common features. The negative ionic fragments from both molecules are formed in the electron energy range from 0 to approximately 14 eV via three resonances (1.2, 5.5, and 8 eV). The relative partial cross sections for DEA Leu and Ile are very similar. The dominant negative ions formed were closed shell negative ions (M-H)- (m/z=130) formed preferentially via low electron energy resonance of 1.23 eV. Additional negative ions with m/z=115, 114, 113, 112, 84, 82, 74, 45, 26, and 17 have been detected.

High-temperature Gas Reactor (HTGR)

NASA Astrophysics Data System (ADS)

Abedi, Sajad

2011-05-01

General Atomics (GA) has over 35 years experience in prismatic block High-temperature Gas Reactor (HTGR) technology design. During this period, the design has recently involved into a modular have been performed to demonstrate its versatility. This versatility is directly related to refractory TRISO coated - particle fuel that can contain any type of fuel. This paper summarized GA's fuel cycle studies individually and compares each based upon its cycle sustainability, proliferation-resistance capabilities, and other performance data against pressurized water reactor (PWR) fuel cycle data. Fuel cycle studies LEU-NV;commercial HEU-Th;commercial LEU-Th;weapons-grade plutonium consumption; and burning of LWR waste including plutonium and minor actinides in the MHR. results show that all commercial MHR options, with the exception of HEU-TH, are more sustainable than a PWR fuel cycle. With LEU-NV being the most sustainable commercial options. In addition, all commercial MHR options out perform the PWR with regards to its proliferation-resistance, with thorium fuel cycle having the best proliferation-resistance characteristics.

Key metrics for HFIR HEU and LEU models

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ilas, Germina; Betzler, Benjamin R.; Chandler, David

This report compares key metrics for two fuel design models of the High Flux Isotope Reactor (HFIR). The first model represents the highly enriched uranium (HEU) fuel currently in use at HFIR, and the second model considers a low-enriched uranium (LEU) interim design fuel. Except for the fuel region, the two models are consistent, and both include an experiment loading that is representative of HFIR's current operation. The considered key metrics are the neutron flux at the cold source moderator vessel, the mass of 252Cf produced in the flux trap target region as function of cycle time, the fast neutronmore » flux at locations of interest for material irradiation experiments, and the reactor cycle length. These key metrics are a small subset of the overall HFIR performance and safety metrics. They were defined as a means of capturing data essential for HFIR's primary missions, for use in optimization studies assessing the impact of HFIR's conversion from HEU fuel to different types of LEU fuel designs.« less

Transformation of Saccharomyces cerevisiae with UV-irradiated single-stranded plasmid.

PubMed

Zgaga, Z

1991-08-01

UV-irradiated single-stranded replicative plasmids were used to transform different yeast strains. The low doses of UV used in this study (10-75 J/m2) caused a significant decrease in the transforming efficiency of plasmid DNA in the Rad+ strain, while they had no effect on transformation with double-stranded plasmids of comparable size. Neither the rev3 mutation, nor the rad18 or rad52 mutations influenced the efficiency of transformation with irradiated single-stranded plasmid. However, it was found to be decreased in the double rev3 rad52 mutant. Extracellular irradiation of plasmid that contains both URA3 and LEU2 genes (psLU) gave rise to up to 5% Leu- transformants among selected Ura+ ones in the repair-proficient strain. Induction of Leu- transformants was dose-dependent and only partially depressed in the rev3 mutant. These results suggest that both mutagenic and recombinational repair processes operate on UV-damaged single-stranded DNA in yeast.

Inhibition of biofilm development and spoilage potential of Shewanella baltica by quorum sensing signal in cell-free supernatant from Pseudomonas fluorescens.

PubMed

Zhao, Aifei; Zhu, Junli; Ye, Xiaofeng; Ge, Yangyang; Li, Jianrong

2016-08-02

The objective of this study was to in vitro evaluate the effect of a cell-free supernatant (CFS) containing quorum sensing (QS) signal of Pseudomonas fluorescens on the growth, biofilm development and spoilage potential of Shewanella baltica, and preliminarily assess the interactive influences of various chemically synthesized autoinducers on spoilage phenotypes of S. baltica. PF01 strain isolated from spoiled Pseudosciaen crocea was identified P. fluorescens. The addition of 25% and 50% CFS to S. baltica culture had no effect on the growth rate during the lag and exponential phase, however, caused cell decline during the stationary phase. The presence of CFS from P. fluorescens significantly inhibited biofilm development, and greatly decreased the production of trimethylamine (TMA) and biogenic amino in S. baltica. Various signal molecules of QS in the CFS of P. fluorescens culture were detected, including seven N-acyl-l-homoserine lactones (AHLs), autoinducer-2 (AI-2) and two diketopiperazines (DKPs). Exogenous supplement of synthesized seven AHLs containing in the CFS decreased biofilm formation and TMA production in S. baltica, while exposure to exogenous cyclo-(l-Pro-l-Leu) was showed to promote spoilage potential, which revealed that S. baltica also sense the two QS molecules. Furthermore, the stimulating effect of cyclo-(l-Pro-l-Leu) was affected when AHL was simultaneously added, suggesting that the inhibitory activity of spoilage phenotypes in S. baltica might be attributed to a competitive effect of these QS compounds in the CFS of P. fluorescens. The present studies provide a good basis for future research on the role of QS in the regulation of spoilage microbial flora. Copyright © 2016 Elsevier B.V. All rights reserved.

Molecular characterization of both alleles in an unusual Tay-Sachs disease BI variant

DOE Office of Scientific and Technical Information (OSTI.GOV)

Coulter-Mackie, M.B.

1994-06-01

In a recent report, the authors described an exon 6 mutation in a Tay-Sachs B1 variant patient, first reported by Gordon et al. (1988), who displayed a typical B1 variant biochemical phenotype - i.e., (a) significant levels of hexosaminidase A (Hex A) activity in an assay with a neutral synthetic substrate, 4-methylumbelliferyl-[beta]-N-acetylglucosamide, and (b) <2% of control Hex A in a test on the sulfated substrate, 4-methylumbelliferyl-[beta]-N-acetylglucosamide-6-sulfate. The patient was found to carry a double mutation (G[sub 574][yields]C [val[sub 192][yields]leu] and G[sub 598][yields]A [val[sub 200][yields]met]) inherited from her mother. Only the 574 mutation produced a deleterious effect on Hex Amore » activity in transfected COS0-1 cells, producing a B1 variant biochemical phenotype. The paternal allele apparently caused decreased abundance of mRNA, since no candidate paternal mutations were found in cloned reverse transcription-PCR (RT-PCR) products in the reported study. The biochemical phenotype of the original patient and the properties of the cDNA carrying the G[sub 574] [yields] C mutation in transient expression studies were compatible with a B1 variant mutation. The possibility remained that there might be some contribution from the paternal allele to the patient's phenotype. However, the paternal allele produces relatively low yields of a largely mis-spliced mRNA whose product would not be functional. Therefore, the G[sub 574] [yields] C (val[yields]leu) mutation in the maternal allele is clearly confirmed as a B1 variant mutation with all the ramifications for the substrate binding site and/or catalytic center that this implies.« less

Pneumolysin Activates Macrophage Lysosomal Membrane Permeabilization and Executes Apoptosis by Distinct Mechanisms without Membrane Pore Formation

PubMed Central

Bewley, Martin A.; Naughton, Michael; Preston, Julie; Mitchell, Andrea; Holmes, Ashleigh; Marriott, Helen M.; Read, Robert C.; Mitchell, Timothy J.; Whyte, Moira K. B.

2014-01-01

ABSTRACT Intracellular killing of Streptococcus pneumoniae is complemented by induction of macrophage apoptosis. Here, we show that the toxin pneumolysin (PLY) contributes both to lysosomal/phagolysosomal membrane permeabilization (LMP), an upstream event programing susceptibility to apoptosis, and to apoptosis execution via a mitochondrial pathway, through distinct mechanisms. PLY is necessary but not sufficient for the maximal induction of LMP and apoptosis. PLY’s ability to induce both LMP and apoptosis is independent of its ability to form cytolytic pores and requires only the first three domains of PLY. LMP involves TLR (Toll-like receptor) but not NLRP3/ASC (nucleotide-binding oligomerization domain [Nod]-like receptor family, pyrin domain-containing protein 3/apoptosis-associated speck-like protein containing a caspase recruitment domain) signaling and is part of a PLY-dependent but phagocytosis-independent host response that includes the production of cytokines, including interleukin-1 beta (IL-1β). LMP involves progressive and selective permeability to 40-kDa but not to 250-kDa fluorescein isothiocyanate (FITC)-labeled dextran, as PLY accumulates in the cytoplasm. In contrast, the PLY-dependent execution of apoptosis requires phagocytosis and is part of a host response to intracellular bacteria that also includes NO generation. In cells challenged with PLY-deficient bacteria, reconstitution of LMP using the lysomotrophic detergent LeuLeuOMe favored cell necrosis whereas PLY reconstituted apoptosis. The results suggest that PLY contributes to macrophage activation and cytokine production but also engages LMP. Following bacterial phagocytosis, PLY triggers apoptosis and prevents macrophage necrosis as a component of a broad-based antimicrobial strategy. This illustrates how a key virulence factor can become the focus of a multilayered and coordinated innate response by macrophages, optimizing pathogen clearance and limiting inflammation. PMID:25293758

DOE Office of Scientific and Technical Information (OSTI.GOV)

Qasim, Mohammad A., E-mail: qasimm@ipfw.edu; Song, Jikui; Markley, John L.

Research highlights: {yields} Large pK shifts in ionizable groups when buried in the protein interior. {yields} Substrate dependent shifts in pH optimum for serine proteases. {yields} Lys side chain is a stronger acid in serine protease S{sub 1} pocket than Asp side chain. -- Abstract: Enzymatic hydrolysis of the synthetic substrate succinyl-Ala-Ala-Pro-Xxx-pNA (where Xxx = Leu, Asp or Lys) catalyzed by bovine chymotrypsin (CHYM) or Streptomyces griseus protease B (SGPB) has been studied at different pH values in the pH range 3-11. The pH optima for substrates having Leu, Asp, and Lys have been found to be 7.5-8.0, 5.5-6.0, andmore » {approx}10, respectively. At the normally reported pH optimum (pH 7-8) of CHYM and SGPB, the substrate with Leu at the reactive site is more than 25,000-fold more reactive than that with Asp. However, when fully protonated, Asp is nearly as good a substrate as Leu. The pK values of the side chains of Asp and Lys in the hydrophobic S{sub 1} pocket of CHYM and SGPB have been calculated from pH-dependent hydrolysis data and have been found to be about 9 for Asp and 7.4 and 9.7 for Lys for CHYM and SGPB, respectively. The results presented in this communication suggest a possible application of CHYM like enzymes in cleaving peptide bonds contributed by acidic amino acids between pH 5 and 6.« less

Posttranslational modification of Ha-ras p21 by farnesyl versus geranylgeranyl isoprenoids is determined by the COOH-terminal amino acid.

PubMed Central

Kinsella, B T; Erdman, R A; Maltese, W A

1991-01-01

ras proteins undergo posttranslational modification by a 15-carbon farnesyl isoprenoid at a cysteine within a defined COOH-terminal amino acid motif; i.e., Cys-Ali-Ali-Ser/Met (where Ali represents an aliphatic residue). In other low molecular mass GTP-binding proteins, cysteines are modified by 20-carbon geranylgeranyl groups within a Cys-Ali-Ali-Leu motif. We changed the terminal Ser-189 of Ha-ras p21 to Leu-189 by site-directed mutagenesis and found that the protein was modified by [3H]geranylgeranyl instead of [3H]farnesyl in an in vitro assay. Gel-permeation chromatography of [3H]mevalonate-labeled hydrocarbons released from immunoprecipitated ras proteins overexpressed in COS cells indicated that Ha-ras p21(Leu-189) was also a substrate for 20-carbon isoprenyl modification in vivo. Additional steps in Ha-ras p21 processing, normally initiated by farnesylation, appear to be supported by geranylgeranylation, based on metabolic labeling of Ha-ras p21(Leu-189) with [3H]palmitate and its subcellular localization in a particulate fraction from COS cells. These observations indicate that the amino acid occupying the terminal position (Xaa) in the Cys-Ali-Ali-Xaa motif constitutes a key structural feature by which Ha-ras p21 and other proteins with ras-like COOH-terminal isoprenylation sites are distinguished as substrates for farnesyl- or geranylgeranyltransferases. Images PMID:1924354

Regulation of taste-active components of meat by dietary branched-chain amino acids; effects of branched-chain amino acid antagonism.

PubMed

Imanari, M; Kadowaki, M; Fujimura, S

2008-05-01

1. The effects of dietary branched-chain amino acids (BCAAs) including leucine (Leu), isoleucine (Ile) and valine (Val) on taste-active components, especially free glutamate (Glu), in meat were investigated. 2. Broiler chickens (28 d old) were given varied dietary BCAA levels for 10 d before marketing. Dietary BCAA content ratios were either 100:100:100 (Low Leu group), 150:100:100 (Control group) or 150:150:150 (High Ile + Val group) for Leu:Ile:Val (% of each BCAA requirement according to NRC, 1994). Taste-related components of meat (free amino acids and ATP metabolites) and sensory scores of meat soup were estimated. 3. Free Glu content, the main taste-active component of meat, was significantly increased by dietary BCAA. Compared to the Control group, free Glu content increased by 30% in the High Ile + Val group. However, the inosine monophosphate (IMP) content in meat did not change among groups. 4. Sensory evaluation of meat soups showed that Control and High Ile + Val groups had different meat flavours. The sensory score of overall taste intensity was significantly higher in the High Ile + Val group. 5. These results suggest that dietary BCAA concentrations regulate free Glu in meat. Increasing dietary Ile + Val induces an increase in free Glu content of meat, improves meat taste and is more effective for increasing free Glu content in meat than decreasing dietary Leu level.

Pivotal Advance: Interconversion between pure chemotactic ligands and chemoattractant/secretagogue ligands of neutrophil C5a receptor by a single amino acid substitution.

PubMed

Jia, Nan; Semba, Umeko; Nishiura, Hiroshi; Kuniyasu, Akihiko; Nsiama, Tienabe K; Nishino, Norikazu; Yamamoto, Tetsuro

2010-06-01

Skp derived from Escherichia coli attracts leukocytes as a pure chemotactic ligand of the C5a receptor. We identified the submolecular region of Skp that binds and activates the C5a receptor to be -Gln103-Asp104-Arg105- using synthetic peptide fragments and site-directed mutants of Skp. As the C5a amino acid residue equivalent to Gln103 of Skp is Leu72, we prepared a Gln103Leu-Skp mutant as a recombinant protein. With this mutation, Skp gained secretagogue functions including induction of the respiratory burst and granule release reactions and leukotriene generation, in addition to the chemoattraction displayed by C5a. However, when we substituted Leu72 with Gln in C5a, the L72Q-C5a mutant largely lost its secretagogue function. These functional conversions were reproduced using synthetic peptides mimicking the receptor-binding/-activating regions of the recombinant proteins. Receptor-binding assays using the mimicking peptides demonstrated only a small difference between the Leu72-C5a and Gln72-C5a peptides. Consistently, L72Q-C5a apparently antagonized C5a secretagogue function. These results indicate that the difference between a chemotactic response and a combined chemotactic/secretory response can be attributed not to the nature of the receptor but to guidance by the ligand, at least in the case of C5a receptor-mediated leukocyte responses.

RNA polymerase II trigger loop residues stabilize and position the incoming nucleotide triphosphate in transcription

PubMed Central

Huang, Xuhui; Wang, Dong; Weiss, Dahlia R.; Bushnell, David A.; Kornberg, Roger D.; Levitt, Michael

2010-01-01

A structurally conserved element, the trigger loop, has been suggested to play a key role in substrate selection and catalysis of RNA polymerase II (pol II) transcription elongation. Recently resolved X-ray structures showed that the trigger loop forms direct interactions with the β-phosphate and base of the matched nucleotide triphosphate (NTP) through residues His1085 and Leu1081, respectively. In order to understand the role of these two critical residues in stabilizing active site conformation in the dynamic complex, we performed all-atom molecular dynamics simulations of the wild-type pol II elongation complex and its mutants in explicit solvent. In the wild-type complex, we found that the trigger loop is stabilized in the “closed” conformation, and His1085 forms a stable interaction with the NTP. Simulations of point mutations of His1085 are shown to affect this interaction; simulations of alternative protonation states, which are inaccessible through experiment, indicate that only the protonated form is able to stabilize the His1085-NTP interaction. Another trigger loop residue, Leu1081, stabilizes the incoming nucleotide position through interaction with the nucleotide base. Our simulations of this Leu mutant suggest a three-component mechanism for correctly positioning the incoming NTP in which (i) hydrophobic contact through Leu1081, (ii) base stacking, and (iii) base pairing work together to minimize the motion of the incoming NTP base. These results complement experimental observations and provide insight into the role of the trigger loop on transcription fidelity. PMID:20798057

Effect of reactor radiation on the thermal conductivity of TREAT fuel

NASA Astrophysics Data System (ADS)

Mo, Kun; Miao, Yinbin; Kontogeorgakos, Dimitrios C.; Connaway, Heather M.; Wright, Arthur E.; Yacout, Abdellatif M.

2017-04-01

The Transient Reactor Test Facility (TREAT) at the Idaho National Laboratory is resuming operations after more than 20 years in latency in order to produce high-neutron-flux transients for investigating transient-induced behavior of reactor fuels and their interactions with other materials and structures. A parallel program is ongoing to develop a replacement core in which the fuel, historically containing highly-enriched uranium (HEU), is replaced by low-enriched uranium (LEU). Both the HEU and prospective LEU fuels are in the form of UO2 particles dispersed in a graphite matrix, but the LEU fuel will contain a much higher volume of UO2 particles, which may create a larger area of interphase boundaries between the particles and the graphite. This may lead to a higher volume fraction of graphite exposed to the fission fragments escaping from the UO2 particles, and thus may induce a higher volume of fission-fragment damage on the fuel graphite. In this work, we analyzed the reactor-radiation induced thermal conductivity degradation of graphite-based dispersion fuel. A semi-empirical method to model the relative thermal conductivity with reactor radiation was proposed and validated based on the available experimental data. Prediction of thermal conductivity degradation of LEU TREAT fuel during a long-term operation was performed, with a focus on the effect of UO2 particle size on fission-fragment damage. The proposed method can be further adjusted to evaluate the degradation of other properties of graphite-based dispersion fuel.

Posttranslational modification of Ha-ras p21 by farnesyl versus geranylgeranyl isoprenoids is determined by the COOH-terminal amino acid

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kinsella, B.T.; Erdman, R.A.; Maltese, W.A.

ras proteins undergo posttranslational modification by a 15-carbon farnesyl isoprenoid at a cysteine within a defined COOH-terminal amino acid motif; i.e., Cys-Ali-Ali-Ser/Met (where Ali represents an aliphatic residue). In other low molecular mass GTP-binding proteins, cysteines are modified by 20-carbon geranylgeranyl groups within a Cys-Ali-Ali-Leu motif. The authors changed the terminal Ser-189 of Ha-ras p21 to Leu-189 by site-directed mutagenesis and found that the protein was modified by ({sup 3}H)geranylgeranyl instead of ({sup 3}H)farnesyl in an in vitro assay. Gel-permeation chromatography of ({sup 3}H)mevalonate-labeled hydrocarbons released from immunoprecipitated ras proteins overexpressed in COS cells indicated that Ha-ras p21 (Leu-189) wasmore » also a substrate for 20-carbon isoprenyl modification in vivo. Additional steps in Ha-ras p21 processing, normally initiated by farnesylation, appear to be supported by geranylgeranylation, based on metabolic labeling of Ha-ras p21 (Leu-189) with ({sup 3}H) palmitate and its subcellular localization in a particulate fraction from COS cells. These observations indicate that the amino acid occupying the terminal position (Xaa) in the Cys-Ali-Ali-Xaa motif constitutes a key structural feature by which Ha-ras p21 and other proteins with ras-like COOH-terminal isoprenylation sites are distinguished as substrates for farnesyl- or geranylgeranyltransferases.« less

No association of the Arg51Gln and Leu72Met polymorphisms of the ghrelin gene and polycystic ovary syndrome.

PubMed

Wang, Kehua; Wang, Leiguang; Zhao, Yueran; Shi, Yuhua; Wang, Laicheng; Chen, Zi-Jiang

2009-02-01

Ghrelin plays a role in regulating glucose metabolism and energy balance. Polymorphisms in preproghrelin and ghrelin gene could be responsible for obesity, insulin resistance and low ghrelin levels observed in some individuals. The objective of this study was to evaluate the influence of two single-nucleotide polymorphisms (SNPs) of ghrelin gene on the clinical, the hormonal and metabolic features in women with polycystic ovary syndrome (PCOS) in a Chinese population. A large sample of Chinese PCOS (n = 271) women and a control group (n = 296) of healthy women matched for age were studied. Hormone and metabolic profiles were measured and blood samples were collected for genotype and allelic frequency analysis. Non-synonymous SNPs in the coding region (exon 2) of the preproghrelin gene (Arg51Gln (346 G>A) and Leu72Met (408 C>A) were studied using PCR and restriction fragment length polymorphism analysis. The polymorphism Arg51Gln was not found in the cohorts studied. The distribution of Leu72Met was similar in PCOS group and in healthy controls. There was no significant difference in age, BMI, waist-hip-ratio and levels of FSH, LH, estradiol, testosterone and prolactin between PCOS patients with different genotypes, and the level of plasma glucose and insulin was also similar. No association was found between Leu72Met and Arg51Gln polymorphisms in the ghrelin gene and PCOS in Chinese population.

Novel pentapeptide, PALAL, derived from a bony fish elicits contraction of the muscle in starfish Patiria pectinifera.

PubMed

Go, Hye-Jin; Kim, Chan-Hee; Oh, Hye Young; Park, Nam Gyu

2016-10-01

A bioactive peptide mimicking peptide-signaling molecules has been isolated from the skin extract of fish Channa argus which caused contraction of the apical muscle of a starfish Patiria pectinifera, a deuterostomian invertebrate. The primary structure of the isolated pentapeptide comprises amino acid sequence of H-Pro-Ala-Leu-Ala-Leu-OH (PALAL) with a molecular mass of 483.7 Da. Pharmacological activity of PALAL, dosage ranging from 10 -9 to 10 -5 M, revealed concentration-dependent contraction of the apical muscles of P. pectinifera and Asterias amurensis. However, PALAL was not active on the intestinal smooth muscle of the goldfish Carassius auratus and has presumably other physiological roles in fish skin. Investigation of structure-activity relationship using truncated and substituted analogs of PALAL demonstrated that H-Ala-Leu-Ala-Leu-OH was necessary and should be sufficient to constrict apical muscle of P. pectinifera. Furthermore, the second alanine residue was required to display the activity, and the fifth leucine residue was responsible for its potency. Comparison with PALAL's primary structure with those of other known bioactive peptides from fish and starfish revealed that PALAL does not have any significant homology. Consequently, PALAL is a bioactive peptide that elicits a muscle contraction in starfish, and the isolation of PALAL may lead to develop other bioactive peptides sharing its similar sequence and/or activity. Copyright © 2016 European Peptide Society and John Wiley & Sons, Ltd. Copyright © 2016 European Peptide Society and John Wiley & Sons, Ltd.

Antigen-antibody interaction. The immunodominant region of EDP208 pili.

PubMed

Worobec, E A; Paranchych, W; Parker, J M; Taneja, A K; Hodges, R S

1985-01-25

The EDP208 pilus contains a major antigenic determinant in the N-terminal dodecapeptide, as shown by E. A. Worobec, A. K. Taneja, R. S. Hodges, and W. Paranchych ((1983) J. Bacteriol. 153, 955-961). This peptide was chemically synthesized, coupled to bovine serum albumin with N-hydroxysuccinimidyl p-azido-benzoate, and used in immunoblot and enzyme-linked immunosorbent assays to show it was capable of reacting with anti-EDP208 pilus antibodies. Antibodies raised against the synthetic peptide conjugate were also capable of reacting with whole pili in these assays. To further examine the specific residues responsible for the antigenicity of this site, several peptide analogs were chemically synthesized. The relative affinity of these peptides for anti-EDP208 pilus antibodies was determined by a competitive enzyme-linked immunosorbent assay using the Fab fragment of anti-EDP208 pilus immunoglobulin G. From these results we established that the antigenic region of this peptide was the N-terminal pentapeptide, N-acetyl-Thr-Asp-Leu-Leu-Ala, and the key residues responsible for the antibody-antigen interaction are the N-acetyl-Thr1, Leu3, and Leu4. Hydrophobic interactions involving the methyl of the acetyl group and the leucine side chains make the largest contributions to the antigen-antibody interaction, while a lesser contribution is made by the Thr1 hydroxyl. The side chains of Asp2 and Ala5 contribute only weakly to the stabilization of the antigen-antibody complex.

Hydrophobic interaction between the SH2 domain and the kinase domain is required for the activation of Csk.

PubMed

Mikkola, Esa T; Gahmberg, Carl G

2010-06-18

The protein tyrosine kinase C-terminal Src kinase (Csk) is activated by the engagement of its Src homology (SH) 2 domain. However, the molecular mechanism required for this is not completely understood. The crystal structure of the active Csk indicates that Csk could be activated by contact between the SH2 domain and the beta3-alphaC loop in the N-terminal lobe of the kinase domain. To study the importance of this interaction for the SH2-domain-mediated activation of Csk, we mutated the amino acid residues forming the contacts between the SH2 domain and the beta3-alphaC loop. The mutation of the beta3-alphaC loop Ala228 to glycine and of the SH2 domain Tyr116, Tyr133, Leu138, and Leu149 to alanine resulted in the inability of the SH2 domain ligand to activate Csk. Furthermore, the overexpressed Csk mutants A228G, Y133A/Y116A, L138A, and L149A were unable to efficiently inactivate endogenous Src in human embryonic kidney 293 cells. The results suggest that the SH2-domain-mediated activation of Csk is dependent on the binding of the beta3-alphaC loop Ala228 to the hydrophobic pocket formed by the side chains of Tyr116, Tyr133, Leu138, and Leu149 on the surface of the SH2 domain. Copyright (c) 2010 Elsevier Ltd. All rights reserved.

Alterations in Topoisomerase IV and DNA Gyrase in Quinolone-Resistant Mutants of Mycoplasma hominis Obtained In Vitro

PubMed Central

Bébéar, Cécile M.; Renaudin, Hélène; Charron, Alain; Bové, Joseph M.; Bébéar, Christiane; Renaudin, Joel

1998-01-01

Mycoplasma hominis mutants were selected stepwise for resistance to ofloxacin and sparfloxacin, and their gyrA, gyrB, parC, and parE quinolone resistance-determining regions were characterized. For ofloxacin, four rounds of selection yielded six first-, six second-, five third-, and two fourth-step mutants. The first-step mutants harbored a single Asp426→Asn substitution in ParE. GyrA changes (Ser83→Leu or Trp) were found only from the third round of selection. With sparfloxacin, three rounds of selection generated 4 first-, 7 second-, and 10 third-step mutants. In contrast to ofloxacin resistance, GyrA mutations (Ser83→Leu or Ser84→Trp) were detected in the first-step mutants prior to ParC changes (Glu84→Lys), which appeared only after the second round of selection. Further analysis of eight multistep-selected mutants of M. hominis that were previously described (2) revealed that they carried mutations in ParE (Asp426→Asn), GyrA (Ser83→Leu) and ParE (Asp426→Asn), GyrA (Ser83→Leu) and ParC (Ser80→Ile), or ParC (Ser80→Ile) alone, depending on the fluoroquinolone used for selection, i.e., ciprofloxacin, norfloxacin, ofloxacin, or pefloxacin, respectively. These data indicate that in M. hominis DNA gyrase is the primary target of sparfloxacin whereas topoisomerase IV is the primary target of pefloxacin, ofloxacin, and ciprofloxacin. PMID:9736554

Nontargeted LC-MS Metabolomics Approach for Metabolic Profiling of Plasma and Urine from Pigs Fed Branched Chain Amino Acids for Maximum Growth Performance.

PubMed

Soumeh, Elham A; Hedemann, Mette S; Poulsen, Hanne D; Corrent, Etienne; van Milgen, Jacob; Nørgaard, Jan V

2016-12-02

The metabolic response in plasma and urine of pigs when feeding an optimum level of branched chain amino acids (BCAAs) for best growth performance is unknown. The objective of the current study was to identify the metabolic phenotype associated with the BCAAs intake level that could be linked to the animal growth performance. Three dose-response studies were carried out to collect blood and urine samples from pigs fed increasing levels of Ile, Val, or Leu followed by a nontargeted LC-MS approach to characterize the metabolic profile of biofluids when dietary BCAAs are optimum for animal growth. Results showed that concentrations of plasma hypoxanthine and tyrosine (Tyr) were higher while concentrations of glycocholic acid, tauroursodeoxycholic acid, and taurocholic acid were lower when the dietary Ile was optimum. Plasma 3-methyl-2-oxovaleric acid and creatine were lower when dietary Leu was optimum. The optimum dietary Leu resulted in increased urinary excretion of ascorbic acid and choline and relatively decreased excretion of 2-aminoadipic acid, acetyl-dl-valine, Ile, 2-methylbutyrylglycine, and Tyr. In conclusion, plasma glycocholic acid and taurocholic acid were discriminating metabolites to the optimum dietary Ile. The optimum dietary Leu was associated with reduced plasma creatine and urinary 2-aminoadipic acid and elevated urinary excretion of ascorbic acid and choline. The optimum dietary Val had a less pronounced metabolic response reflected in plasma or urine than other BCAA.

Leucine, Not Total Protein, Content of a Supplement Is the Primary Determinant of Muscle Protein Anabolic Responses in Healthy Older Women.

PubMed

Devries, Michaela C; McGlory, Chris; Bolster, Douglas R; Kamil, Alison; Rahn, Maike; Harkness, Laura; Baker, Steven K; Phillips, Stuart M

2018-06-13

Older adults show a blunted muscle protein synthesis (MPS) response to postprandial hyperaminoacidemia relative to younger adults. Evidence suggests that this anabolic resistance can be overcome by consuming greater quantities of leucine. The purpose of this trial was to determine whether the addition of leucine to a smaller dose (10 g) of milk proteins would, when compared with a larger dose (25 g) of whey protein isolate (WPI), result in similar increases in acute (hourly) and integrated (daily) myofibrillar protein synthesis (myoPS). Healthy older (mean ± SD age: 69 ± 1 y) women (n = 11/group) were randomly assigned with the use of a single-blind, parallel-group design to twice-daily consumption of either WPI [25 g WPI (3 g l-leucine)] or leucine (LEU; 10 g milk protein with 3 g total l-leucine) for 6 d. Participants performed unilateral resistance exercise to allow assessment of the impact of the supplement alone and with resistance exercise. We determined acute (13C6-phenylanine) and integrated [using deuterated water (D2O)] rates of myoPS in the fasting (acute), basal (integrated), nonexercised, and exercised states. Acute myoPS increased in both legs in response to LEU (fed: 45%; fed+exercise: 71%; P < 0.001) and WPI (fed: 29%; fed+exercise: 47%; P < 0.001) compared with fasting; the increase was greater with LEU than with WPI in the exercised leg (46%; P = 0.04) but not in the rested leg (P = 0.07). The acute myoPS response was greater in the exercised leg than in the rested leg for both WPI (63%) and LEU (58%) (P < 0.001). Integrated myoPS increased with WPI and LEU in the exercised leg (both 9%; P < 0.001) during supplementation, and with WPI (3%; P = 0.02) but not LEU (2%, P = 0.1) in the rested leg compared with the basal state. A lower-protein (10 compared with 25 g/dose), leucine-matched beverage induced similar increases in acute and integrated myoPS in healthy older women. Lower-protein supplements with added leucine may represent an advantageous approach in older adults to maintain skeletal muscle anabolic sensitivity and attenuate muscle loss; however, further work is needed using longer-term interventions to substantiate these findings. This trial was registered at www.clinicaltrials.gov as NCT02282566.

THE FINAL DEMISE OF EAST TENNESSEE TECHNOLOGY PARK BUILDING K-33 Health Physics Society Annual Meeting West Palm Beach, Florida June 27, 2011

DOE Office of Scientific and Technical Information (OSTI.GOV)

David A. King

2011-06-27

Building K-33 was constructed in 1954 as the final section of the five-stage uranium enrichment cascade at the Oak Ridge Gaseous Diffusion Plant (ORGDP). The two original building (K-25 and K-27) were used to produce weapons grade highly enriched uranium (HEU). Building K-29, K-31, and K-33 were added to produce low enriched uranium (LEU) for nuclear power plant fuel. During ORGDP operations K-33 produced a peak enrichment of 2.5%. Thousands of tons of reactor tails fed into gaseous diffusion plants in the 1950s and early 1960s introducing some fission products and transuranics. Building K-33 was a two-story, 25-meters (82-feet) tallmore » structure with approximately 30 hectare (64 acres) of floor space. The Operations (first) Floor contained offices, change houses, feed vaporization rooms, and auxiliary equipment to support enrichment operations. The Cell (second) Floor contained the enrichment process equipment and was divided into eight process units (designated K-902-1 through K-902-8). Each unit contained ten cells, and each cell contained eight process stages (diffusers) for a total of 640 enrichment stages. 1985: LEU buildings were taken off-line after the anticipated demand for uranium enrichment failed to materialize. 1987: LEU buildings were placed in permanent shutdown. Process equipment were maintained in a shutdown state. 1997: DOE signed an Action Memorandum for equipment removal and decontamination of Buildings K-29, K-31, K-33; BNFL awarded contract to reindustrialize the buildings under the Three Buildings D&D and Recycle Project. 2002: Equipment removal complete and effort shifts to vacuuming, chemical cleaning, scabbling, etc. 2005: Decontamination efforts in K-33 cease. Building left with significant {sup 99}Tc contamination on metal structures and PCB contamination in concrete. Uranium, transuranics, and fission products also present on building shell. 2009: DOE targets Building K-33 for demolition. 2010: ORAU contracted to characterize Building K-33 for final disposition at the Environmental Management Waste Management Facility (EMWMF) in Oak Ridge. ORAU collected 439 samples from May and June. LATA Sharp started removing transite panels in September. 2011: LATA Sharp began demolition in January and expects the last waste shipment to EMWMF in September. Approximately 237,000 m{sup 3} (310,000 yd{sup 3}, bulked) of waste taken to EMWMF in 23,000 truckloads expected by project completion.« less

Nutritional supplement products: Does the label information influence purchasing decisions for the physically active?

PubMed

Gabriels, Gary; Lambert, Mike

2013-10-02

The increase in sales of nutritional supplement globally can be attributed, in part, to aggressive marketing by manufacturers, rather than because the nutritional supplements have become more effective. Furthermore, the accuracy of the labelling often goes unchallenged. Therefore, any effects of the supplement, may be due to contaminants or adulterants in these products not reflected on the label. A self-administered questionnaire was used to determine how consumers of nutritional supplements acquired information to assist their decision-making processes, when purchasing a product. The study was approved by the University of Cape Town, Faculty of Health Sciences Human Research Ethics Committee. The questionnaire consisted of seven, closed and open-ended questions. The participants were asked to respond to the questions according to a defined list of statements. A total of 259 participants completed and returned questionnaires. The data and processing of the returned questionnaires was captured using Windows-based Microsoft® Office Excel 2003 SP 1 (Excel © 1985-2003 Microsoft Corporation). Statistica Version 10 (copyright © Stat Soft, Inc. 1984-2011) was used to calculate the descriptive statistics. The main finding of the study was that nearly 70% of the respondents who purchased supplements were strongly influenced by container label information that stipulated that the nutritional supplement product is free of banned substances. The second finding was that just over 50% of the respondents attached importance to the quality of the nutritional supplement product information on the container label. The third finding was that about 40% of the respondents were strongly influenced by the ingredients on the labels when they purchased nutritional supplements. This study, (i) identifies short-comings in current labelling information practices, (ii) provides opportunities to improve label and non-label information and communication, and, (iii) presents the case for quality assurance laboratory "screening testing" of declared and undeclared contaminants and/or adulterants, that could have negative consequences to the consumer.

Nutritional supplement products: does the label information influence purchasing decisions for the physically active?

PubMed Central

2013-01-01

Background The increase in sales of nutritional supplement globally can be attributed, in part, to aggressive marketing by manufacturers, rather than because the nutritional supplements have become more effective. Furthermore, the accuracy of the labelling often goes unchallenged. Therefore, any effects of the supplement, may be due to contaminants or adulterants in these products not reflected on the label. Methods A self-administered questionnaire was used to determine how consumers of nutritional supplements acquired information to assist their decision-making processes, when purchasing a product. The study was approved by the University of Cape Town, Faculty of Health Sciences Human Research Ethics Committee. The questionnaire consisted of seven, closed and open-ended questions. The participants were asked to respond to the questions according to a defined list of statements. A total of 259 participants completed and returned questionnaires. The data and processing of the returned questionnaires was captured using Windows-based Microsoft® Office Excel 2003 SP 1 (Excel © 1985–2003 Microsoft Corporation). Statistica Version 10 (copyright © Stat Soft, Inc. 1984–2011) was used to calculate the descriptive statistics. Results The main finding of the study was that nearly 70% of the respondents who purchased supplements were strongly influenced by container label information that stipulated that the nutritional supplement product is free of banned substances. The second finding was that just over 50% of the respondents attached importance to the quality of the nutritional supplement product information on the container label. The third finding was that about 40% of the respondents were strongly influenced by the ingredients on the labels when they purchased nutritional supplements. Conclusion This study, (i) identifies short-comings in current labelling information practices, (ii) provides opportunities to improve label and non-label information and communication, and, (iii) presents the case for quality assurance laboratory “screening testing” of declared and undeclared contaminants and/or adulterants, that could have negative consequences to the consumer. PMID:24088193

CERCA LEU fuel assemblies testing in Maria Reactor - safety analysis summary and testing program scope.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pytel, K.; Mieleszczenko, W.; Lechniak, J.

2010-03-01

The presented paper contains neutronic and thermal-hydraulic (for steady and unsteady states) calculation results prepared to support annex to Safety Analysis Report for MARIA reactor in order to obtain approval for program of testing low-enriched uranium (LEU) lead test fuel assemblies (LTFA) manufactured by CERCA. This includes presentation of the limits and operational constraints to be in effect during the fuel testing investigations. Also, the scope of testing program (which began in August 2009), including additional measurements and monitoring procedures, is described.

Backbone and sidechain methyl Ile (δ1), Leu and Val chemical shift assignments of RDE-4 (1-243), an RNA interference initiation protein in C. elegans.

PubMed

Chiliveri, Sai Chaitanya; Kumar, Sonu; Marelli, Udaya Kiran; Deshmukh, Mandar V

2012-10-01

The RNAi pathway of several organisms requires presence of double stranded RNA binding proteins for functioning of Dicer in gene regulation. In C. elegans, a double stranded RNA binding protein, RDE-4 (385 aa, 44 kDa) recognizes long exogenous dsRNA and initiates the RNAi pathway. We have achieved complete backbone and stereospecific methyl sidechain Ile (δ1), Leu and Val chemical shifts of first 243 amino acids of RDE-4, namely RDE-4ΔC.

Hemoglobin Cleavage Site-Specificity of the Plasmodium falciparum Cysteine Proteases Falcipain-2 and Falcipain-3

PubMed Central

Subramanian, Shoba; Hardt, Markus; Choe, Youngchool; Niles, Richard K.; Johansen, Eric B.; Legac, Jennifer; Gut, Jiri; Kerr, Iain D.; Craik, Charles S.; Rosenthal, Philip J.

2009-01-01

The Plasmodium falciparum cysteine proteases falcipain-2 and falcipain-3 degrade host hemoglobin to provide free amino acids for parasite protein synthesis. Hemoglobin hydrolysis has been described as an ordered process initiated by aspartic proteases, but cysteine protease inhibitors completely block the process, suggesting that cysteine proteases can also initiate hemoglobin hydrolysis. To characterize the specific roles of falcipains, we used three approaches. First, using random P1 – P4 amino acid substrate libraries, falcipain-2 and falcipain-3 demonstrated strong preference for cleavage sites with Leu at the P2 position. Second, with overlapping peptides spanning α and β globin and proteolysis-dependent 18O labeling, hydrolysis was seen at many cleavage sites. Third, with intact hemoglobin, numerous cleavage products were identified. Our results suggest that hemoglobin hydrolysis by malaria parasites is not a highly ordered process, but rather proceeds with rapid cleavage by falcipains at multiple sites. However, falcipain-2 and falcipain-3 show strong specificity for P2 Leu in small peptide substrates, in agreement with the specificity in optimized small molecule inhibitors that was identified previously. These results are consistent with a principal role of falcipain-2 and falcipain-3 in the hydrolysis of hemoglobin by P. falciparum and with the possibility of developing small molecule inhibitors with optimized specificity as antimalarial agents. PMID:19357776

The control of vascular endothelial cell injury.

PubMed

Murota, S; Morita, I; Suda, N

1990-01-01

The mechanism by which MCI-186 showed a potent cytoprotective effect on the in vitro endothelial cell injury due to 15-HPETE was studied. Stimulation of human leukocytes with various chemical mediators such as TPA, f-Met-Leu-Phe, LTB4, etc. elicited the production of active oxygens, which could be detected by luminol-dependent chemiluminescence. Among the chemical mediators tested, TPA elicited the chemiluminescence the most, and f-Met-Leu-Phe and LTB4 came next. When the leukocytes were directly placed on a monolayer of cultured endothelial cells, followed by stimulating the leukocytes with TPA, severe endothelial cell injury was observed. The effect of TPA was dose dependent. There was good correlation between the active oxygen releasing activity and the cytotoxic activity. When the leukocytes were placed on a filter which was set apart from the monolayer of endothelial cell in a culture dish, and stimulated the leukocytes with TPA, no cytotoxicity was observed. These data strongly suggest that the substance responsible for the cytotoxicity must be a very labile and short-lived substance, presumably active oxygens. On the other hand, MCI-186 was found to have a complete quenching activity to the chemiluminescence due to active oxygens in the TPA-leukocyte system. Taken together, these factors indicate that the potent cytoprotective effect of MCI-186 may be due to its specific radical scavenging activity.

Identification of novel targets for HIV-1: Molecular dynamics simulation and binding energy calculations

NASA Astrophysics Data System (ADS)

Pandey, Vishnudatt; Tiwari, Gargi; Mall, Vijaya Shri; Tiwari, Rakesh Kumar; Ojha, R. P.

2018-05-01

HIV-1 envelope glycoprotein-mediated fusion is managed by the concerted coalescence of the HIV-1 gp41 N- and C- helical regions, which is a product in the formation of 6-helix bundles. These two regions are considered prime targets for peptides and antibodies that inhibit HIV-1 entry. There are so many rational method aimed to attach a rationally designed artificial tail to the C-terminus of HIV-1 fusion inhibitors to increase their antiviral potency. Here M. D. simulation was performed to go insight for study of C-terminal tail of Ile-Asp-Leu (IDL).

Corrosion Evaluation of RERTR Uranium Molybdenum Fuel

DOE Office of Scientific and Technical Information (OSTI.GOV)

A K Wertsching

2012-09-01

As part of the National Nuclear Security Agency (NNSA) mandate to replace the use of highly enriched uranium (HEU) fuel for low enriched uranium (LEU) fuel, research into the development of LEU fuel for research reactors has been active since the late 1970’s. Originally referred to as the Reduced Enrichment for Research and Test Reactor (RERTR) program the new effort named Global Threat Reduction Initiative (GTRI) is nearing the goal of replacing the standard aluminum clad dispersion highly enriched uranium aluminide fuel with a new LEU fuel. The five domestic high performance research reactors undergoing this conversion are High Fluxmore » Isotope reactor (HFIR), Advanced Test Reactor (ATR), National Institute of Standards and Technology (NIST) Reactor, Missouri University Research Reactor (MURR) and the Massachusetts Institute of Technology Reactor II (MITR-II). The design of these reactors requires a higher neutron flux than other international research reactors, which to this point has posed unique challenges in the design and development of the new mandated LEU fuel. The new design utilizes a monolithic fuel configuration in order to obtain sufficient 235U within the LEU stoichoimetry to maintain the fission reaction within the domestic test reactors. The change from uranium aluminide dispersion fuel type to uranium molybdenum (UMo) monolithic configuration requires examination of possible corrosion issues associated with the new fuel meat. A focused analysis of the UMo fuel under potential corrosion conditions, within the ATR and under aqueous storage indicates a slow and predictable corrosion rate. Additional corrosion testing is recommended for the highest burn-up fuels to confirm observed corrosion rate trends. This corrosion analysis will focus only on the UMo fuel and will address corrosion of ancillary components such as cladding only in terms of how it affects the fuel. The calculations and corrosion scenarios are weighted with a conservative bias to provide additional confidence with the results. The actual corrosion rates of UMo fuel is very likely to be lower than assumed within this report which can be confirmed with additional testing.« less

Specific patterns of gyrA mutations determine the resistance difference to ciprofloxacin and levofloxacin in Klebsiella pneumoniae and Escherichia coli

PubMed Central

2013-01-01

Background Wide use of ciprofloxacin and levofloxacin has often led to increased resistance. The resistance rate to these two agents varies in different clinical isolates of Enterobacteriaceae. Mutations of GyrA within the quinolone resistance-determining regions have been found to be the main mechanism for quinolone resistance in Enterobacteriaceae. It has been shown that only some of the mutations in the gyrA gene identified from clinical sources were involved in fluoroquinolone resistance. Whether different patterns of gyrA mutation are related to antimicrobial resistance against ciprofloxacin and levofloxacin is unclear. Methods The minimum inhibitory concentration (MIC) of ciprofloxacin and levofloxacin were determined by the agar dilution method followed by PCR amplification and sequencing of the quinolone resistance determining region of gyrA to identify all the mutation types. The correlation between fluoroquinolone resistance and the individual mutation type was analyzed. Results Resistance differences between ciprofloxacin and levofloxacin were found in 327 isolates of K. pneumoniae and E. coli in Harbin, China and in the isolates reported in PubMed publications. GyrA mutations were found in both susceptible and resistant isolates. For the isolates with QRDR mutations, the resistance rates to ciprofloxacin and levofloxacin were also statistically different. Among the 14 patterns of alterations, two single mutations (Ser83Tyr and Ser83Ile), and three double mutations (Ser83Leu+Asp87Asn, Ser83Leu+Asp87Tyr and Ser83Phe+Asp87Asn) were associated with both ciprofloxacin and levofloxacin resistance. Two single mutations (Ser83Phe and Ser83Leu) were related with ciprofloxacin resistance but not to levofloxacin. Resistance difference between ciprofloxacin and levofloxacin in isolates harboring mutation Ser83Leu+Asp87Asn were of statistical significance among all Enterobacteriaceae (P<0.001). Conclusions Resistance rate to ciprofloxacin and levofloxacin were statistically different among clinical isolates of Enterobacteriaceae harboring GyrA mutations. Ser83Leu+Asp87Asn may account for the antimicrobial resistance difference between ciprofloxacin and levofloxacin. PMID:23295059

The Dual Regulatory Role of Amino Acids Leu480 and Gln481 of Prothrombin*

PubMed Central

Wiencek, Joesph R.; Hirbawi, Jamila; Yee, Vivien C.; Kalafatis, Michael

2016-01-01

Prothrombin (FII) is activated to α-thrombin (IIa) by prothrombinase. Prothrombinase is composed of a catalytic subunit, factor Xa (fXa), and a regulatory subunit, factor Va (fVa), assembled on a membrane surface in the presence of divalent metal ions. We constructed, expressed, and purified several mutated recombinant FII (rFII) molecules within the previously determined fVa-dependent binding site for fXa (amino acid region 473–487 of FII). rFII molecules bearing overlapping deletions within this significant region first established the minimal stretch of amino acids required for the fVa-dependent recognition exosite for fXa in prothrombinase within the amino acid sequence Ser478–Val479–Leu480–Gln481–Val482. Single, double, and triple point mutations within this stretch of rFII allowed for the identification of Leu480 and Gln481 as the two essential amino acids responsible for the enhanced activation of FII by prothrombinase. Unanticipated results demonstrated that although recombinant wild type α-thrombin and rIIaS478A were able to induce clotting and activate factor V and factor VIII with rates similar to the plasma-derived molecule, rIIaSLQ→AAA with mutations S478A/L480A/Q481A was deficient in clotting activity and unable to efficiently activate the pro-cofactors. This molecule was also impaired in protein C activation. Similar results were obtained with rIIaΔSLQ (where rIIaΔSLQ is recombinant human α-thrombin with amino acids Ser478/Leu480/Gln481 deleted). These data provide new evidence demonstrating that amino acid sequence Leu480–Gln481: 1) is crucial for proper recognition of the fVa-dependent site(s) for fXa within prothrombinase on FII, required for efficient initial cleavage of FII at Arg320; and 2) is compulsory for appropriate tethering of fV, fVIII, and protein C required for their timely activation by IIa. PMID:26601957

Affinity of Smectite and Divalent Metal Ions (Mg(2+), Ca(2+), Cu(2+)) with L-leucine: An Experimental and Theoretical Approach Relevant to Astrobiology.

PubMed

Pandey, Pramod; Pant, Chandra Kala; Gururani, Kavita; Arora, Priyanka; Pandey, Neetu; Bhatt, Preeti; Sharma, Yogesh; Negi, Jagmohan Singh; Mehata, Mohan Singh

2015-12-01

Earth is the only known planet bestowed with life. Several attempts have been made to explore the pathways of the origin of life on planet Earth. The search for the chemistry which gave rise to life has given answers related to the formation of biomonomers, and their adsorption on solid surfaces has gained much attention for the catalysis and stabilization processes related to the abiotic chemical evolution of the complex molecules of life. In this communication, surface interactions of L-leucine (Leu) on smectite (SMT) group of clay (viz. bentonite and montmorillonite) and their divalent metal ion (Mg(2+), Ca(2+) and Cu(2+)) incorporated on SMT has been studied to find the optimal conditions of time, pH, and concentration at ambient temperature (298 K). The progress of adsorption was followed spectrophotometrically and further characterized by FTIR, SEM/EDS and XRD. Leu, a neutral/non polar amino acid, was found to have more affinity in its zwitterionic form towards Cu(2+)- exchanged SMT and minimal affinity for Mg(2+)- exchanged SMT. The vibrational frequency shifts of -NH3 (+) and -COO(-) favor Van der Waal's forces during the course of surface interaction. Quantum calculations using density functional theory (DFT) have been applied to investigate the absolute value of metal ion affinities of Leu (Leu-M(2+) complex, M = Mg(2+), Ca(2+), Cu(2+)) with the help of their physico-chemical parameters. The hydration effect on the relative stability and geometry of the individual species of Leu-M(2+) × (H2O)n, (n =2 and 4) has also been evaluated within the supermolecule approach. Evidence gathered from investigations of surface interactions, divalent metal ions affinities and hydration effects with biomolecules may be important for better understanding of chemical evolution, the stabilization of biomolecules on solid surfaces and biomolecular-metal interactions. These results may have implications for understanding the origin of life and the preservation of biomarkers.

Temperature-driven adaptation of the bacterial community in peat measured by using thymidine and leucine incorporation.

PubMed

Ranneklev, S B; Bååth, E

2001-03-01

The temperature-driven adaptation of the bacterial community in peat was studied, by altering temperature to simulate self-heating and a subsequent return to mesophilic conditions. The technique used consisted of extracting the bacterial community from peat using homogenization-centrifugation and measuring the rates of thymidine (TdR) or leucine (Leu) incorporation by the extracted bacterial community at different temperatures. Increasing the peat incubation temperature from 25 degrees C to 35, 45, or 55 degrees C resulted in a selection of bacterial communities whose optimum temperatures for activity correlated to the peat incubation temperatures. Although TdR and Leu incorporations were significantly correlated, the Leu/TdR incorporation ratios were affected by temperature. Higher Leu/TdR incorporation ratios were found at higher temperatures of incubation of the extracted bacterial community. Higher Leu/TdR incorporation ratios were also found for bacteria in peat samples incubated at higher temperatures. The reappearance of the mesophilic community and disappearance of the thermophilic community when the incubation temperature of the peat was shifted down were monitored by measuring TdR incorporation at 55 degrees C (thermophilic activity) and 25 degrees C (mesophilic activity). Shifting the peat incubation temperature from 55 to 25 degrees C resulted in a recovery of the mesophilic activity, with a subsequent disappearance of the thermophilic activity. The availability of substrate for bacterial growth varied over time and among different peat samples. To avoid confounding effects of substrate availability, a temperature adaptation index was calculated. This index consisted of the log(10) ratio of TdR incorporation at 55 and 25 degrees C. The temperature index decreased linearly with time, indicating that no thermophilic activity would be detected by the TdR technique 1 month after the temperature downshift. There were no differences between the slopes of the temperature adaptation indices over time for peat samples incubated at 55 degrees C 3 or 11 days before incubation at 25 degrees C. Thus, different levels of bacterial activity did not affect the temperature-driven adaptation of the bacterial community.

Temperature-Driven Adaptation of the Bacterial Community in Peat Measured by Using Thymidine and Leucine Incorporation

PubMed Central

Ranneklev, Sissel Brit; Bååth, Erland

2001-01-01

The temperature-driven adaptation of the bacterial community in peat was studied, by altering temperature to simulate self-heating and a subsequent return to mesophilic conditions. The technique used consisted of extracting the bacterial community from peat using homogenization-centrifugation and measuring the rates of thymidine (TdR) or leucine (Leu) incorporation by the extracted bacterial community at different temperatures. Increasing the peat incubation temperature from 25°C to 35, 45, or 55°C resulted in a selection of bacterial communities whose optimum temperatures for activity correlated to the peat incubation temperatures. Although TdR and Leu incorporations were significantly correlated, the Leu/TdR incorporation ratios were affected by temperature. Higher Leu/TdR incorporation ratios were found at higher temperatures of incubation of the extracted bacterial community. Higher Leu/TdR incorporation ratios were also found for bacteria in peat samples incubated at higher temperatures. The reappearance of the mesophilic community and disappearance of the thermophilic community when the incubation temperature of the peat was shifted down were monitored by measuring TdR incorporation at 55°C (thermophilic activity) and 25°C (mesophilic activity). Shifting the peat incubation temperature from 55 to 25°C resulted in a recovery of the mesophilic activity, with a subsequent disappearance of the thermophilic activity. The availability of substrate for bacterial growth varied over time and among different peat samples. To avoid confounding effects of substrate availability, a temperature adaptation index was calculated. This index consisted of the log10 ratio of TdR incorporation at 55 and 25°C. The temperature index decreased linearly with time, indicating that no thermophilic activity would be detected by the TdR technique 1 month after the temperature downshift. There were no differences between the slopes of the temperature adaptation indices over time for peat samples incubated at 55°C 3 or 11 days before incubation at 25°C. Thus, different levels of bacterial activity did not affect the temperature-driven adaptation of the bacterial community. PMID:11229900

FURTHER ASSESSMENTS OF THE ATTRACTIVENESS OF MATERIALS IN ADVANCED NUCLEAR FUEL CYCLES FROM A SAFEGUARDS PERSPECTIVE

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bathke, C. G.; Jarvinen, G. D.; Wallace, R. K.

2008-10-01

This paper summarizes the results of an extension to an earlier study [ ] that examined the attractiveness of materials mixtures containing special nuclear materials (SNM) associated with the PUREX, UREX+, and COEX reprocessing schemes. This study focuses on the materials associated with the UREX, COEX, THOREX, and PYROX reprocessing schemes. This study also examines what is required to render plutonium as “unattractive.” Furthermore, combining the results of this study with those from the earlier study permits a comparison of the uranium and thorium based fuel cycles on the basis of the attractiveness of the SNM associated with each fuelmore » cycle. Both studies were performed at the request of the United States Department of Energy (DOE), and are based on the calculation of “attractiveness levels” that has been couched in terms chosen for consistency with those normally used for nuclear materials in DOE nuclear facilities [ ]. The methodology and key findings will be presented. Additionally, how these attractiveness levels relate to proliferation resistance (e.g. by increasing impediments to the diversion, theft, undeclared production of SNM for the purpose of acquiring a nuclear weapon), and how they could be used to help inform policy makers, will be discussed.« less

Transport of a Novel Angiotensin-I-Converting Enzyme Inhibitory Peptide Ala-His-Leu-Leu Across Human Intestinal Epithelial Caco-2 Cells.

PubMed

Li, Ying; Zhao, Jiangtao; Liu, Xiaoli; Xia, Xiudong; Wang, Ying; Zhou, Jianzhong

2017-03-01

The transport behavior and absorption mechanism of Ala-His-Leu-Leu (AHLL) intestinal absorption in Caco-2 cell monolayers were clarified systemically. The safe absorptive concentration of AHLL was 200 μg/mL, which was determined by the 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide assay. The permeation of AHLL was concentration dependent in a bidirectional transfer and reached a plateau at 90 min. The efflux ratio was above 0.5, suggesting that AHLL was absorbed by both active transport and passive diffusion. The apparent permeability coefficients (P app ) of AHLL both from the apical (AP) to basolateral (BL) side (P app AB) and from the BL to AP side (P app BA) decreased when the temperature was lowered from 37°C to 4°C.The uptake of AHLL was more at pH 7.4 than at other pHs. Both verapamil and (E)-3-[[[3-[2-(7-chloro-2- quinolinyl) ethenyl] phenyl]-[[(3-dimethyl amino)-3-oxopropyl]thio] methyl] thio]-propanoic acid (MK571) inhibited the absorption of AHLL, indicating that P-glycoprotein and multi-drug resistant proteins (MRPs) were all involved in AHLL secretion, especially multi-drug resistant protein 2 (MRP2). AHLL was transported through both trans- and paracellular pathways across the Caco-2 cell monolayer. This work first elucidates the AHLL absorption mechanism in Caco-2 cells and provides the basis for future studies on the improvement of bioavailability.

Identification of a nuclear localization sequence in the polyomavirus capsid protein VP2

NASA Technical Reports Server (NTRS)

Chang, D.; Haynes, J. I. 2nd; Brady, J. N.; Consigli, R. A.; Spooner, B. S. (Principal Investigator)

1992-01-01

A nuclear localization signal (NLS) has been identified in the C-terminal (Glu307-Glu-Asp-Gly-Pro-Gln-Lys-Lys-Lys-Arg-Arg-Leu318) amino acid sequence of the polyomavirus minor capsid protein VP2. The importance of this amino acid sequence for nuclear transport of newly synthesized VP2 was demonstrated by a genetic "subtractive" study using the constructs pSG5VP2 (expressing full-length VP2) and pSG5 delta 3VP2 (expressing truncated VP2, lacking amino acids Glu307-Leu318). These constructs were transfected into COS-7 cells, and the intracellular localization of the VP2 protein was determined by indirect immunofluorescence. These studies revealed that the full-length VP2 was localized in the nucleus, while the truncated VP2 protein was localized in the cytoplasm and not transported to the nucleus. A biochemical "additive" approach was also used to determine whether this sequence could target nonnuclear proteins to the nucleus. A synthetic peptide identical to VP2 amino acids Glu307-Leu318 was cross-linked to the nonnuclear proteins bovine serum albumin (BSA) or immunoglobulin G (IgG). The conjugates were then labeled with fluorescein isothiocyanate and microinjected into the cytoplasm of NIH 3T6 cells. Both conjugates localized in the nucleus of the microinjected cells, whereas unconjugated BSA and IgG remained in the cytoplasm. Taken together, these genetic subtractive and biochemical additive approaches have identified the C-terminal sequence of polyoma-virus VP2 (containing amino acids Glu307-Leu318) as the NLS of this protein.

Effect of reactor radiation on the thermal conductivity of TREAT fuel

DOE PAGES

Mo, Kun; Miao, Yinbin; Kontogeorgakos, Dimitrios C.; ...

2017-02-04

The Transient Reactor Test Facility (TREAT) at the Idaho National Laboratory is resuming operations after more than 20 years in latency in order to produce high-neutron-flux transients for investigating transient-induced behavior of reactor fuels and their interactions with other materials and structures. A parallel program is ongoing to develop a replacement core in which the fuel, historically containing highly-enriched uranium (HEU), is replaced by low-enriched uranium (LEU). Both the HEU and prospective LEU fuels are in the form of UO 2 particles dispersed in a graphite matrix, but the LEU fuel will contain a much higher volume of UO 2more » particles, which may create a larger area of interphase boundaries between the particles and the graphite. This may lead to a higher volume fraction of graphite exposed to the fission fragments escaping from the UO 2 particles, and thus may induce a higher volume of fission-fragment damage on the fuel graphite. In this work, we analyzed the reactor-radiation induced thermal conductivity degradation of graphite-based dispersion fuel. A semi-empirical method to model the relative thermal conductivity with reactor radiation was proposed and validated based on the available experimental data. Prediction of thermal conductivity degradation of LEU TREAT fuel during a long-term operation was performed, with a focus on the effect of UO 2 particle size on fission-fragment damage. Lastly, the proposed method can be further adjusted to evaluate the degradation of other properties of graphite-based dispersion fuel.« less

Role of Annular Lipids in the Functional Properties of Leucine Transporter LeuT Proteomicelles.

PubMed

LeVine, Michael V; Khelashvili, George; Shi, Lei; Quick, Matthias; Javitch, Jonathan A; Weinstein, Harel

2016-02-16

Recent work has shown that the choice of the type and concentration of detergent used for the solubilization of membrane proteins can strongly influence the results of functional experiments. In particular, the amino acid transporter LeuT can bind two substrate molecules in low concentrations of n-dodecyl β-d-maltopyranoside (DDM), whereas high concentrations reduce the molar binding stoichiometry to 1:1. Subsequent molecular dynamics (MD) simulations of LeuT in DDM proteomicelles revealed that DDM can penetrate to the extracellular vestibule and make stable contacts in the functionally important secondary substrate binding site (S2), suggesting a potential competitive mechanism for the reduction in binding stoichiometry. Because annular lipids can be retained during solubilization, we performed MD simulations of LeuT proteomicelles at various stages of the solubilization process. We find that at low DDM concentrations, lipids are retained around the protein and penetration of detergent into the S2 site does not occur, whereas at high concentrations, lipids are displaced and the probability of DDM binding in the S2 site is increased. This behavior is dependent on the type of detergent, however, as we find in the simulations that the detergent lauryl maltose-neopentyl glycol, which is approximately twice the size of DDM and structurally more closely resembles lipids, does not penetrate the protein even at very high concentrations. We present functional studies that confirm the computational findings, emphasizing the need for careful consideration of experimental conditions, and for cautious interpretation of data in gathering mechanistic information about membrane proteins.

Role of Annular Lipids in the Functional Properties of Leucine Transporter LeuT Proteomicelles

PubMed Central

2016-01-01

Recent work has shown that the choice of the type and concentration of detergent used for the solubilization of membrane proteins can strongly influence the results of functional experiments. In particular, the amino acid transporter LeuT can bind two substrate molecules in low concentrations of n-dodecyl β-d-maltopyranoside (DDM), whereas high concentrations reduce the molar binding stoichiometry to 1:1. Subsequent molecular dynamics (MD) simulations of LeuT in DDM proteomicelles revealed that DDM can penetrate to the extracellular vestibule and make stable contacts in the functionally important secondary substrate binding site (S2), suggesting a potential competitive mechanism for the reduction in binding stoichiometry. Because annular lipids can be retained during solubilization, we performed MD simulations of LeuT proteomicelles at various stages of the solubilization process. We find that at low DDM concentrations, lipids are retained around the protein and penetration of detergent into the S2 site does not occur, whereas at high concentrations, lipids are displaced and the probability of DDM binding in the S2 site is increased. This behavior is dependent on the type of detergent, however, as we find in the simulations that the detergent lauryl maltose-neopentyl glycol, which is approximately twice the size of DDM and structurally more closely resembles lipids, does not penetrate the protein even at very high concentrations. We present functional studies that confirm the computational findings, emphasizing the need for careful consideration of experimental conditions, and for cautious interpretation of data in gathering mechanistic information about membrane proteins. PMID:26811944

Polymorphisms of Mannose-binding Lectin and Toll-like Receptors 2, 3, 4, 7 and 8 and the Risk of Respiratory Infections and Acute Otitis Media in Children.

PubMed

Toivonen, Laura; Vuononvirta, Juho; Mertsola, Jussi; Waris, Matti; He, Qiushui; Peltola, Ville

2017-05-01

Mannose-binding lectin (MBL) and toll-like receptors (TLRs) are important components of the innate immune system. We assessed the susceptibility of children with genetic variants in these factors to respiratory infections, rhinovirus infections and acute otitis media. In a prospective cohort study, blood samples from 381 Finnish children were analyzed for polymorphisms in MBL2 at codons 52, 54 and 57, TLR2 Arg753Gln, TLR3 Leu412Phe, TLR4 Asp299Gly, TLR7 Gln11Leu and TLR8 Leu651Leu. Children were followed up for respiratory infections until 24 months of age with daily diaries. Polymerase chain reaction and antigen tests were used for detection of respiratory viruses from nasal swabs. Children with MBL variant genotype had a mean of 59 days with symptoms of respiratory infection per year, compared with 49 days in those with wild-type (P = 0.01). TLR8 polymorphisms were associated with an increased risk and TLR7 polymorphisms with a decreased risk of recurrent rhinovirus infections (P = 0.02 for both). TLR2 polymorphisms were associated with recurrent acute otitis media (P = 0.02). MBL polymorphisms were associated with an increased and TLR7 polymorphisms with a decreased risk of rhinovirus-associated acute otitis media (P = 0.03 and P = 0.006, respectively). Genetic polymorphisms in MBL and TLRs promote susceptibility to or protection against respiratory infections. In addition to environmental factors, genetic variations may explain why some children are more prone to respiratory infections.

The CRISPR/Cas Immune System Is an Operon Regulated by LeuO, H-NS, and Leucine-Responsive Regulatory Protein in Salmonella enterica Serovar Typhi ▿ †

PubMed Central

Medina-Aparicio, L.; Rebollar-Flores, J. E.; Gallego-Hernández, A. L.; Vázquez, A.; Olvera, L.; Gutiérrez-Ríos, R. M.; Calva, E.; Hernández-Lucas, I.

2011-01-01

Prokaryotes have developed multiple strategies to survive phage attack and invasive DNA. Recently, a novel genetic program denominated the CRISPR/Cas system was demonstrated to have a role in these biological processes providing genetic immunity. This defense mechanism is widespread in the Archaea and Bacteria, suggesting an ancient origin. In the last few years, progress has been made regarding the functionality of the CRISPR/Cas system; however, many basic aspects of the system remain unknown. For instance, there are few studies about the conditions and regulators involved in its transcriptional control. In this work, we analyzed the transcriptional organization of the CRISPR/Cas system as well as the positive and negative regulators involved in its genetic expression in Salmonella enterica serovar Typhi. The results obtained show that in S. Typhi the CRISPR/Cas system is a LeuO-dependent operon silenced by the global regulator LRP, in addition to the previously known nucleoid-associated protein H-NS; both LRP and H-NS bind upstream and downstream of the transcriptional start site of casA. In this study, relevant nucleotides of the casA regulatory region that mediate its LeuO transcriptional activation were identified. Interestingly, specific growth conditions (N-minimal medium) were found for the LeuO-independent expression of the CRISPR/Cas system in S. Typhi. Thus, our work provides evidence that there are multiple modulators involved in the genetic expression of this immune system in S. Typhi IMSS-1. PMID:21398529