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1
Urano, Nobuyuki. "Studies of microbial aminoalcohol dehydrogenase : biochemical analysis and application to chiral compound production." Kyoto University, 2007. http://hdl.handle.net/2433/136512.
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Kyoto University (京都大学)0048
新制・課程博士
博士(農学)
甲第13092号
農博第1597号
新制||農||938(附属図書館)
学位論文||H19||N4218(農学部図書室)
UT51-2007-H365
京都大学大学院農学研究科応用生命科学専攻
(主査)教授 清水 昌, 教授 喜多 恵子, 教授 江﨑 信芳
学位規則第4条第1項該当
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Holmstrand, Henry. "Compound-specific stable chlorine isotope analysis : a versatile tool for investigating biochemical and geochemical processes of organochlorine substances /." Stockholm : Department of Applied Environmental Science (ITM), Stockholm University, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-937.
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Roppola, K. (Katri). "Environmental applications of manometric respirometric methods." Doctoral thesis, University of Oulu, 2009. http://urn.fi/urn:isbn:9789514290794.
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Abstract
In this work a manometric respirometric measuring system was applied to practical environmental cases related to wastewater management and biodegradation studies of oil-contaminated soils and materials used in landfill structures. Pollution of groundwater, surface water and soils is a worldwide problem. Therefore, tests simulating the biodegradation behaviour of organic compounds in water media and soils have become increasingly important. Respirometric methods provide direct measurement of the oxygen consumed by micro-organisms in biodegradation processes from an air or oxygen-enriched environment in a closed vessel.
Biochemical oxygen demand (BOD) is a crucial environmental parameter used to measure the quality of water and treatment results in wastewater. Generally, BOD is measured with standardised methods, which are usually time-consuming as well as laborious. In this work the manometric respirometric test was compared with conventional BOD tests by determining the BOD of pulp and paper mills as well as domestic wastewater samples. The effect of different factors such as type, amount and pre-treatment of inoculum and the effect of dilution of a sample on the BOD values were also tested. A right dilution was noticed to be the most significant factor affecting the BOD values of the industrial wastewater samples. The mathematic estimation of the BOD7 values from the respirometric data was proved to work reliably after a 2–3 day incubation period. Characterisation of organic fractions of the pulp and paper mill wastewater was carried out with methods including filtration, long term BOD measurements and COD analyses. The most significant observation in characterisation analyses was that a remarkable part of the detected oxygen demand was consumed for the biotransformation of biodegradable fractions into new inert decomposition products, not only for mineralisation of the biodegradable COD fraction.
Biodegradation behaviour of the peat samples with different decomposition rates was studied in order to evaluate the applicable peat types that can be used in landfill structures. Only minor (BOD/ThOD < 0.4%) biodegradation was observed with compaction peat samples, and the stable state, in which biodegradation stopped, was achieved during a two month period. The manometric respirometric method was also applied for the biodegradation studies in which the effect of the modification of soil properties on biodegradation rates of bio-oils was tested. Modified properties were the nutrient content and the pH of the soil. Fertiliser addition and pH adjustment increased both the BOD/ThOD% values of the model substances and the precision of the measurement. The manometric respirometric method was proved to be an advanced method for simulating biodegradation processes in soil and water media.
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Abdou, Bouba Armand. "Contribution à l’étude du développement d’un aliment fonctionnel à base d’épices du Cameroun : caractérisation physico-chimique et fonctionnelle." Thesis, Vandoeuvre-les-Nancy, INPL, 2009. http://www.theses.fr/2009INPL006N/document.
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La recrudescence des maladies dégénératives ces dernières décennies dans le monde a amené plusieurs chercheurs et médecins à médiatiser les antioxydants à cause des vertus qu’on leur prête: de la protection contre les maladies cardiovasculaires à la prévention de certains cancers. Le présent travail a été mené avec pour objectif principal d’évaluer le pouvoir antioxydant des épices entrant dans la préparation de la sauce en vue du développement d’un complément alimentaire nutraceutique. Pour ce faire, vingt épices largement consommées ont été choisies sur la base d’une enquête exploratoire menée au Cameroun. Les différentes épices réduites en poudres ont été analysées pour leurs teneurs en composition nutritionnelle. Le pouvoir antiradicalaire in vitro des extraits méthanoliques des différentes épices a été déterminé ainsi que le pouvoir anti-inflammatoire et antistress sur des rats adultes à stress induit. Les résultats obtenus ont montré des variations très significatives de la composition des épices. L’activité antioxydante utilisant la méthode au N’ N-diphényl-N’-picrylhydrazyl (DPPH), au « trolox equivalent antioxidant capacity » (TEAC) et le pouvoir réducteur total (PRT) ont révélé que Z. leprieurii et D. glomerata présentent les activités particulièrement élevées. Les extraits de ces deux épices ont servi de base à la préparation de mélange dont l’effet a été testé sur des rats mâles à inflammation induite. Les résultats obtenus ont montré que les épices individuelles et leur mélange à des doses de 100 mg/kg et 150 mg/kg présentent une activité anti-inflammatoire importante comparable à ceux commerciaux: inodméthacine, déxaméthasone et célécoxib. La variation de la teneur en malonaldéhyde (marqueur de l’oxydantion lipidique) a révélée l’action antioxydante in vivo des extraits, démontrant ainsi leur potentiel dans le développement de compléments alimentaires à effet antistressIncreasing evidences from current research point to the fact that certain disease conditions can be prevented through the consumption of antioxidant rich foods. The present work was carried out to evaluate the antioxidant potentials of twenty Cameroonian spices commonly used in some Cameroonian cuisine. The nutritional properties of spices, the in vitro antioxidant potential of their methanolic extracts as well as the in vivo antioxidant potential of the methanolic extracts of some selected samples were determined. The antioxidant activity brought about by N’ N-diphenyl-N’-picrylhydrazyl (DPPH), «trolox antioxidant equivalent capacity» (TEAC) and the total reduction power (PRT) methods have revealed that Z. leprieurii and D. glomerata presented the highest activities. The extracts of the two spices were used to prepare a mixture whose effect was tested on male rats with induced inflammation. The results obtained indicate that the individual spices and their mixture at 100 mg/kg and 150 mg/kg present an important anti-inflammatory activity comparable to that of commercial anti-inflammatory like indomethacin, dexamethasone and celecoxib. The variation of malondialdehyde content (a lipidic oxidant marquer) revealed the in vivo antioxidant action of extracts, thus demonstrating their potential for the development of functional foods with anti-stress effect
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Mills, Sarah Victoria. "Novel biochemical compounds from Antarctic microorganisms." Thesis, University of Nottingham, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.342463.
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James, Donny Lawrence. "Biochemical dechlorination of hexachloro-1,3-butadiene /." Murdoch University Digital Theses Program, 2009. http://wwwlib.murdoch.edu.au/adt/browse/view/adt-MU20100216.212048.
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Bazara, Salem Mohammed. "Biochemical studies on the toxicity and carcinogenicity of PCBs and related compounds." Thesis, Brunel University, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.235935.
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Tavana-Roudsari, Aria. "Crystallization from supercritical fluids; application to pharmaceutical and biochemical compounds." Diss., The University of Arizona, 1990. http://hdl.handle.net/10150/185194.
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Crystallization from supercritical fluids was studied as a nontoxic, noncontaminating alternative to conventional techniques for purification and size manipulation of pharmaceutical solids. To proceed with crystallization solubilities of several pharmaceutical compounds in supercritical carbon dioxide were experimentally determined and modeled using solid-vapor phase equilibria. The compounds studied included benzoic acid, salicylic acid, aspirin, griseofulvin, and digoxin among others. A high pressure crystallizer was constructed and operated in batch and continuous modes. Supersaturation was generated by various schemes, such as optimal pressure reduction and salting-out. It was determined that, depending on the crystallization scheme, particles can be produced at submicron as well as large sizes. Particle nucleation and growth rates from saturated supercritical solutions were estimated and the product size distributions were simulated using the population balance theory. Observations were made regarding habit and morphology of particles nucleated and grown at supercritical conditions.
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Reid, Karen A. "Biochemical studies of fluoroacetate and 4-fluorothreonine biosynthesis in Streptomyces cattleya." Thesis, Queen's University Belfast, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.241432.
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Martin, Jason Lewis. "Biochemical and pharmacological studies of morphine-6-glucuronide and related compounds." Thesis, Loughborough University, 1994. https://dspace.lboro.ac.uk/2134/13901.
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Morphine-6-glucuronide is a minor metabolite. representing 5% of an administered dose of morphine. The metabolite has analgesic activity exceeding that of morphine and may contribute to analgesia following morphine administration. The aims of the study were to attempt to identify the reasons behind the improved activity of morphine-6-glucuronide over the parent compound and to examine a series of 6-substituted compounds, based on 6-substituted benzoate esters, as potential mimics of morphine-6-glucuronide. Morphine-6-glucuronide was seen to have similar affinity to morphine at l1-opioid receptors as assessed by ligand-binding assays in mouse brain homogenates. However a three-fold improved affinity at S-opioid receptor binding sites was observed and a ten-fold reduction in affinity at K-opioid sites. Using in vitro bioassay systems the glucuronide showed a two-fold improved potency over morphine in both the guinea-pig ileum and the mouse vas deferens preparations. Following in vivo (s.c.) administration in the mouse the glucuronide was seen to be equipotent with morphine in the tail-flick test, but was of much longer duration, lasting up to 9 hours. Exvivo binding assays confirmed that morphine-like material was still present in the central nervous system six hours after administration of the glucuronide, but was not observed at a similar time after morphine administration. Activity was retained if the hydroxyl groups of the sugar moiety of the glucuronide were protected as esters. In contrast the more prevalent morphine metabolite morphine-3-glucuronide was inactive in all in vitro and in vivo tests used and did not antagonise morphine in vitro or in vivo. A group of 3-substituted derivatives containing saturated and unsaturated substituents did show affinity for opioid receptors but no agonist activity of the compounds could be demonstrated in vitro. A series of synthetic 6-substituted compounds showed a variety of affinities for, and agonist potencies at, opioid receptors, though low affinity at Kopioid receptors was a general finding. For example, morphine-6- nitrobenzoate was l1-opioid receptor preferring, while morphine-6- phthalate had improved O-opioid receptor affinity and acted via Il-opioid receptors in the mouse vas deferens and in vivo. However the compounds were weaker than morphine and the duration of action in vivo was shorter than morphine-6-glucuronide. The conclusions from these studies are that morphine-6-glucuronide and morphine have similar in vitro affinities at the l1-receptor, although morphine-6-glucuronide has somewhat improved binding affinity for Il receptor sites, it has less affinity for K receptor sites. Pharmacokinetic reasons are probably responsible for the improved activity and duration of action of morphine-6-glucuronide over morphine. None of the synthetic compounds examined are potentially useful as direct mimics of the glucuronide because morphine-6-glucuronide is more potent and has a longer duration of action than the synthetic derivatives, though alteration at the 6-position of the morphine nucleus can lead to dramatic changes in selectivity and potency of ligands for the differing opioid receptors.
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Tsui, Yuen-kee. "Uncovering new compounds for treatment of intervertebral disc degeneration by chemical genetics." Click to view the E-thesis via HKUTO, 2009. http://sunzi.lib.hku.hk/hkuto/record/B43571943.
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Ljunggren, Joel. "Biochemical Interactions of Some Saproxylic Fungi." Licentiate thesis, Mittuniversitetet, Avdelningen för naturvetenskap, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:miun:diva-25068.
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Interactions are all around us, and as humans we may use words and gestures to communicate our intentions. At the micro level of fungi, communications are replaced by chemical signals and structure. These interactions fall into three distinctive categories: synergistic, where organisms help each other, as is the case with ectomycorrhizal fungi and tree roots, deadlock, or combat, where organisms fight for or defend a resource. When it comes to fungi-tree interactions, the fungi group of basidiomycetes fall into the latter category. At the onset of fungal infection, a living tree defends itself by producing resinous substances such as terpenes. These compounds are frequently found in hydrodistilled turpentine, which makes turpentine a prime source of antifungal compounds. A D-optimal design of fractionated turpentine together with gas chromatography (GC) coupled to a mass spectrometer was employed to find the most biologically active constituent of turpentine. Growth rate of Coniophora puteana was used to assess the efficacy of the mixed fractions. The partial least squares projection model had an excellent predictive power (R2 = 0.988, Q2 = 0.825) and validity. A putative sesquiterpene was identified as the most active compound for inhibiting fungal growth. The model was corroborated by an external validation assay employing preparative GC. After the death of a tree, fungi are no longer hindered by secondary metabolites from the tree. Instead, other interspecies interactions and intraspecies interactions, such as fungi-fungi interactions, occur. We found that when the white-rot fungus Heterobasidion parviporum and brown-rot fungus Gloeophyllum sepiarium interact with each other, amino acids are used to a higher extent. Amino acids may be used to produce antifungal compounds to hinder the other species from growing. Lysine in particular was utilized to a greater extent during interaction. Glutamine was the only amino acid that increased in concentration. Glutamine might be exuded or converted by enzymes from already existing glutamic acid. Dry weights suggest that the fungi were in a deadlock and that nutrient limitation might be a determining factor. It seemed that H. parviporum was favoured by a decrease in pH while the opposite pattern may be true for G. sepiarium.
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Tsui, Yuen-kee, and 崔婉琪. "Uncovering new compounds for treatment of intervertebral disc degeneration by chemical genetics." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2009. http://hub.hku.hk/bib/B43571943.
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McLeod, John Edward. "Marker studies of nickel silicide formation." Master's thesis, University of Cape Town, 1988. http://hdl.handle.net/11427/15903.
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Includes bibliographical references.Atomic diffusion during the solid state formation of thin films of nickel silicides (Ni2Si and NiSi) from nickel and amorphous silicon has been investigated using 31Si radioactive tracer and inert marker techniques. Samples were prepared by vacuum deposition of thin films of nickel and silicon, followed by thermal annealing to effect silicide growth. The radioactive tracer investigation of Ni2Si showed nickel to be the diffusing species during silicide growth. Sharply defined Ni2si* profiles of 100% radioactive concentration at the sample surface were - obtained. The results are compared with previous results in which the profiles were more spread out and of lower surface concentration. The radioactive tracer investigation of NiSi formation showed that nickel is also the diffusing species during second phase growth. The NiSi * layer was found to be of 100% concentration. Some spreading of the activity profile near the NiSi/NiSi* interface was observed. The results were consistent with previous 31Si tracer work on NiSi formation and also with the present Ni * 2Si results. The inert marker investigation used an ultra-thin (5-10 A) continuous layer of Mo or Ta to monitor atomic movement during silicide growth. The results confirmed nickel to be the diffusing species during the growth of both phases. These results are in excellent agreement with previous inert marker studies of nickel silicide growth.
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Azmi, Jahanara Khanam. "NMR spectroscopic and chemometric studies on the biochemical effects of substituted aromatic compounds." Thesis, Imperial College London, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.271470.
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Agboh, Kelvin Christopher. "Characterization of ATP analogue cross-linking compounds and biochemical analysis of P2X receptors." Thesis, University of Leicester, 2007. http://hdl.handle.net/2381/8243.
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The aim of this thesis was to test whether cross-linking ATP analogues could be used to provide direct evidence of the amino acid residues which contribute to the ATP binding domain of P2X receptors. The UV irradiation of 2-azido ATP caused the compound to cross-link to the P2X1 receptor and caused a significant reduction in the response to ATP. The reduction of cross-linking following the pre-treatment of cells in excess ATP suggested competition between ATP and 2-azido ATP for occupancy of the P2X receptor binding site. This was proven with the radio-labelling of the P2X1 receptor with 2-azido [y32p] ATP. Similar techniques were used to identify other photo-reactive compounds with activity at the P2X1 receptor. These photo-reactive compounds had reactive sites at different coordinates around the ATP molecule and can potentially cross-link to different regions within the ATP binding domain. In an attempt to localize the ATP binding site, the P2X1 receptor was tagged with flag and his epitopes and purified. Protein mass fingerprinting showed that the digestion of the P2X1 protein did not provide enough coverage of the protein to guarantee successful analysis by mass spectrometry. Additionally, initial studies using digestion to identify peptide fragments which had bound to 2-azido [y32P] ATP showed that experimental conditions caused the cleavage of the label from the peptide. This thesis has demonstrated that photo-reactive ATP analogues can be used to label the P2X receptors. Further work should identify a suitable combination of enzymes to efficiently fragment the protein and allow spectral analysis to identify the amino acid residues which covalently bind to each photo-reactive compound. This would give the first direct evidence of the contributing amino acid residues in the ATP binding domain of the P2X receptors.
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Felemban, S. G. "Biochemical effects of organophosphorous compounds on cultured rat and human cardiomyocyte-like cells." Thesis, Nottingham Trent University, 2016. http://irep.ntu.ac.uk/id/eprint/30096/.
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At present, little is known about the effect(s) of organophosphorous compounds (OPs) on cardiomyocytes. The present study aimed to investigate the effects of phenyl saligenin phosphate (PSP), two organophosphorothioate insecticides (diazinon and chlorpyrifos), and their acutely toxic metabolites (diazoxon and chlorpyrifos oxon) on rat H9c2 and human cardiomyocyte-like cells. The rat embryonic H9c2 myoblast cell line, which has the ability to differentiate into a cardiac muscle phenotype, can be instrumental in understanding OP cytotoxicity at different differentiation stages. Human induced pluripotent stem cell derived cardiomyocytes (hiPSC-CMs) were used for the validation of selected OP effects in a more human relevant system. The differentiation of both H9c2 and human cardiomyocytes resulted in increased expression of differentiated muscle markers such as troponin 1, tropomyosin and α-actin. OP-induced cytotoxicity was assessed by monitoring MTT reduction, LDH release, and caspase-3 activity. Cell death was not observed in mitotic or differentiated H9c2 cells with diazinon, diazoxon, or chlorpyrifos oxon (48 h exposure; 200 μM). Chlorpyrifos-induced cell death was only evident at concentrations >100 μM. In marked contrast, PSP displayed pronounced cytotoxicity towards both mitotic and differentiated H9c2 cells. PSP triggered the activation of JNK1/2, suggesting a role for this pro-apoptotic protein kinase in PSP-induced cell death, which was attenuated by the JNK1/2 inhibitor SP 600125, confirming the role of JNK1/2 activation in PSP-induced cytotoxicity. Dansylated PSP was used to identify novel PSP binding proteins. 2D-gel electrophoresis profiles of cells treated with dansylated PSP (25 μM) were used to identify proteins fluorescently labeled with dansylated PSP. Proteomic analysis identified tropomyosin, heat shock protein β-1 and nucleolar protein 58 as novel protein targets for PSP. The present study also examined the effect of sublethal concentrations of OP on differentiating H9c2 cells. This was assessed by monitoring morphological changes, levels of cardiac cytoskeleton protein expression and AChE activity in cells induced to differentiate in the presence and absence of OPs. Results showed that exposure to diazinon and chlorpyrifos induced morphological changes, AChE inhibition and decreases in troponin 1 expression. Morphological changes were observed with PSP treated cells concomitant with altered expression of cardiac cytoskeleton proteins, troponin 1, tropomyosin, α-actin and other novel proteins. When hiPSC-CMs were employed to validate differences in cardiac toxicity induced by OPs, a similar cardiotoxic pattern when compared to differentiated H9c2 cells. In summary, PSP induced cytotoxicity was associated with JNK activation and apoptrosis whereas little cytotoxicity was observed with the other OPs. However PSP, chlorpyrifos and diazinon induced sub-lethal effects in cultured H9c2 and hiPSC-CMs were associated with decrease levels of cardiac cytoskeleton protein expression.
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Peng, Chen. "Synthesis of very-long-chain bifunctional and isotope-labeled compounds for biochemical investigations into novel compounds in plant cuticular waxes." Thesis, University of British Columbia, 2012. http://hdl.handle.net/2429/43752.
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Plant cuticles are the interface for plant-environment interactions, and the first barrier protecting plants from environmental stresses such as water loss and pathogens. Structurally, the cuticle consists of a hydrophobic polymer lattice, cutin, and cuticular waxes deposited inside and outside cutin. The major components of the cuticular waxes are aliphatics derived from very-long-chain (VLC) fatty acids, such as alkanes and aldehydes. Besides compounds with primary functionalities, some compounds with two or more functional groups have also been identified in cuticular waxes. However, only limited knowledge about them has been acquired so far.
The current work was to identify novel 1,2- and 1,3-bifunctional wax compounds from various plant species, in order to expand our current understanding of their structure, biosynthesis and function in plant cuticles. Synthetic methods were first developed to produce various VLC 1,2- and 1,3-bifunctionalized standard compounds for current and future structure elucidation studies. Unknown compounds found in Cosmos bipinnatus petal wax were identified as alkane-1,2-diol monoacetates by GC-MS, with chain lengths ranging from C20 to C24. The ratio between the primary and the secondary monoacetates was quantified to be 3:5, as opposed to the thermodynamic equilibrium ratio of 7:3. Novel β-hydroxy acid methyl esters were also identified from Aloe arborescens leaf wax, with chain lengths ranging from C26 to C30. In addition, two NMR-based methods were established to study the stereoconfigurations of alkane-1,2-diols from C. bipinnatus petal wax, and the carbons bearing secondary hydroxyl functionality were determined to have predominately the R-configuration.
Apart from the research on bifunctional compounds, synthetic methods to produce β-deuterium labeled VLC substrates were also established. The resulting C30 fatty acid methyl ester was double-labeled and can be used directly or indirectly as substrates in future biochemical assays. At last, the hypothetic substrate for the CER1 enzyme implicated in wax alkane biosynthesis, C30 aldehyde, was synthesized and used in in vivo assays with heterologously expressed protein.
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Kalantzi, Olga Ioanna. "Residues and biochemical effects of PBDEs and selected organohalogen compounds in humans and seals." Thesis, Lancaster University, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.423891.
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Laidlay, Sharada. "Bioassay-guided isolation and biochemical characterisation of vasorelaxant compounds extracted from a Dalbergia species." Thesis, University of Brighton, 2016. https://research.brighton.ac.uk/en/studentTheses/90f9b2b4-e0bd-4872-902f-598bc357c02c.
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Natural products have been the source of many of our successful drugs providing us with an unrivalled chemical diversity combined with drug-like properties. The search for bioactive compounds can be helped considerably by the phytotherapeutic knowledge held by indigenous communities. In this study solvent extracts from the bark of a Dalbergia species and used by a community in Borneo, will be investigated to isolate, identify and biochemically characterise compounds showing vasorelaxation. At the core of this study is the hypertensive model, which uses phenylephrine precontracted rat aortic rings as a bioassay to identify solvent extracts, fractions and sub-fractions that cause relaxation. These fractions are generated using chromatographic techniques and solvent systems developed specifically for this purpose. Structural elucidation of the isolated compounds was undertaken by studying extensive data from UV, MS, 1D and 2D 1H and 13C NMR spectra. This study also undertook the pharmacological characterisation of the isolated compounds using the same bioassay together with enzyme and receptor inhibitors to identify the signalling pathways involved.
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Woznichak, Michelle Marie Gill. "Investigation of the biochemical activity of phenylaminoethyl selenide compounds, synthetic substrate analogs for dopamine beta-monooxygenase." Diss., Georgia Institute of Technology, 1999. http://hdl.handle.net/1853/26211.
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Tang, Sharon Shuk Lan. "Phytochemical and biochemical investigation of Ochna macrocalyx and Bupleurum fruitcosum - searching for NF-kB inhibitory compounds." Thesis, University College London (University of London), 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.406410.
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El-Fawal, Hassan Ahmed Naguib. "Involvement of calcium in organophosphorus-induced delayed neuropathy: a functional morphological, and biochemical study." Diss., Virginia Polytechnic Institute and State University, 1989. http://hdl.handle.net/10919/54520.
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Organophosphorus compounds are widely used in agriculture as pesticides and in industry as petroleum additives and modifiers of plastics. Some of these compounds are capable of inducing an irreversible neuropathy developing weeks to months after exposure, yet there is no effective treatment. This may be due in part to the lack of knowledge of how this neuropathy develops.
In this dissertation, it is proposed that as a consequence of a triggering event, peripheral nerves may be predisposed to an increase in calcium (Ca⁺⁺) mobilization and the neuronal accumulation of this cation. This increase in Ca could thereby initiate a cascade of events, in both nerve and muscle, that may account for some of the detrimental changes occurring during organophosphorus-induced delayed neuropathy (OPIDN).
The involvement of Ca⁺⁺ in the pathogenesis of OPIDN was tested using functional, morphological, and biochemical techniques in the domestic hen, the recognized animal model of OPIDN.
The isolated biventer cervicis nerve-muscle preparation was developed for quick assessment of the time course of OPIDN deficits and validated by comparison to in vivo preparations. This preparation proved more sensitive by functional and morphological evaluation indicating early damage at 4 days following exposure and before appearance of clinical signs. Regeneration was detected after 21 days.
OPIDN was modified by using Ca⁺⁺ channel blockers, nifedipine, and verapamil, in the presence of phenyl saligenin phosphate, an active neurotoxicant. Attenuation of OPIDN by these compounds was revealed by clinical assessment, by changes in nerve excitability denoted by strength-duration relationships in response to electrical stimulation, by denervation hypersensitivity to neurotransmitter, and by morphology. These modifiers attenuated all degenerative responses.
Furthermore, it was revealed that the activity of Ca⁺⁺-activated neutral protease (CANP), an enzyme responsible for neurofilament degradation, was increased in OPIDN. Such increases were ameliorated by modifiers of Ca movement.
This study strongly suggests that Ca⁺⁺, possibly through activation of CANP, may contribute to functional and morphological deficits of OPIDN.Ph. D.
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Bhasin, Aman K. K. [Verfasser], and Claus [Akademischer Betreuer] Jacob. "Synthesis and elucidation of biochemical mode of action of organoselenium compounds against cancer / Aman K. K. Bhasin. Betreuer: Claus Jacob." Saarbrücken : Saarländische Universitäts- und Landesbibliothek, 2014. http://d-nb.info/1060715937/34.
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Viswanathan, Uma Maheswari [Verfasser], and Claus [Akademischer Betreuer] Jacob. "Study of antimicrobial, biochemical and nanotechnological aspects of novel sulfur, selenium and tellurium compounds / Uma Maheswari Viswanathan. Betreuer: Claus Jacob." Saarbrücken : Saarländische Universitäts- und Landesbibliothek, 2014. http://d-nb.info/1058360779/34.
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Mohammad, Hussein Islam Tohamy. "Molecular and biochemical studies of feline herpesvirus-1 thymidine kinase and its role in the development of effective antiviral compounds." Thesis, University of Cambridge, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.613034.
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Chaw, Donna. "Biochemical changes in the fermentation bedding of the "pig-on-litter" method of pig farming : with special emphasis on biodegradation of nitrogen compounds and odour production /." Hong Kong : University of Hong Kong, 1996. http://sunzi.lib.hku.hk/hkuto/record.jsp?B17592240.
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Güell, Serra Mireia. "Theoretical studies of systems of biochemical interest containing Fe and Cu transition metals." Doctoral thesis, Universitat de Girona, 2009. http://hdl.handle.net/10803/7941.
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La presència de la química teòrica i computacional està augmentant en quasi tots els camps de la recerca en química. Els càlculs teòrics poden ajudar a entendre millor l'estructura, les propietats i la reactivitat de compostos metàl·lics d'àrees tan diferents com la química inorgànica, organometàl·lica i bioinorgànica. No obstant això, és imprescindible utilitzar la metodologia adequada per obtenir resultats teòrics fiables. Els estudis d'aquesta tesi es poden dividir en dos grups diferents. El primer grup inclou l'estudi teòric del mecanisme de reacció de diversos sistemes que contenen coure i tenen diferents estructures Cun-O2. Aquests estudies s'han dut a terme amb l'objectiu de profunditzar en la natura dels processos oxidants químics i biològics promoguts per sistemes que contenen coure. En la segona part de la tesi, s'estudia la fiabilitat de diferents tècniques utilitzades per estudiar l'estructura electrònica i la reactivitat de sistemes que contenen coure, ferro i altres metalls de transició.The presence of computational and theoretical chemistry is increasing in chemical research in nearly all fields. Theoretical calculations can help to better explain structure, properties, and reactivity in metallic compounds, in such diverse areas as inorganic, organometallic and bioinorganic chemistry. However, it is essential to use the suitable methodology in order to obtain reliable theoretical results. The studies of this Thesis can be divided into two different groups. The first group includes the theoretical study of the reaction mechanism of several copper-containing systems with different Cun-O2 structures. These studies are carried out with the aim of providing some insight into the nature of the chemical and biological copper-promoted oxidative processes with 1:1 and 2:1 Cu(I)/O2-derived species. In the second part of this Thesis the reliability of different theoretical approaches used to study the electronic structure and reactivity of systems containing copper, iron or other transition metals is evaluated.
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Jalal, Ahmed Hasnain. "Multivariate Analysis for the Quantification of Transdermal Volatile Organic Compounds in Humans by Proton Exchange Membrane Fuel Cell System." FIU Digital Commons, 2018. https://digitalcommons.fiu.edu/etd/3886.
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In this research, a proton exchange membrane fuel cell (PEMFC) sensor was investigated for specific detection of volatile organic compounds (VOCs) for point-of-care (POC) diagnosis of the physiological conditions of humans. A PEMFC is an electrochemical transducer that converts chemical energy into electrical energy. A Redox reaction takes place at its electrodes whereas the volatile biomolecules (e.g. ethanol) are oxidized at the anode and ambient oxygen is reduced at the cathode. The compounds which were the focus of this investigation were ethanol (C2H5OH) and isoflurane (C3H2ClF5O), but theoretically, the sensor is not limited to only those VOCs given proper calibration.
Detection in biosensing, which needs to be carried out in a controlled system, becomes complex in a multivariate environment. Major limitations of all types of biosensors would include poor selectivity, drifting, overlapping, and degradation of signals. Specific detection of VOCs in multi-dimensional environments is also a challenge in fuel cell sensing. Humidity, temperature, and the presence of other analytes interfere with the functionality of the fuel cell and provide false readings. Hence, accurate and precise quantification of VOC(s) and calibration are the major challenges when using PEMFC biosensor.
To resolve this problem, a statistical model was derived for the calibration of PEMFC employing multivariate analysis, such as the “Principal Component Regression (PCR)” method for the sensing of VOC(s). PCR can correlate larger data sets and provides an accurate fitting between a known and an unknown data set. PCR improves calibration for multivariate conditions as compared to the overlapping signals obtained when using linear (univariate) regression models.
Results show that this biosensor investigated has a 75% accuracy improvement over the commercial alcohol breathalyzer used in this study when detecting ethanol. When detecting isoflurane, this sensor has an average deviation in the steady-state response of ~14.29% from the gold-standard infrared spectroscopy system used in hospital operating theaters.
The significance of this research lies in its versatility in dealing with the existing challenge of the accuracy and precision of the calibration of the PEMFC sensor. Also, this research may improve the diagnosis of several diseases through the detection of concerned biomarkers.
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Brengel, Christian [Verfasser], and Rolf W. [Akademischer Betreuer] Hartmann. "Strategies to evade resistance: combining biophysical and biochemical approaches to discover compounds addressing new bacterial target systems / Christian Brengel ; Betreuer: Rolf W. Hartmann." Saarbrücken : Saarländische Universitäts- und Landesbibliothek, 2016. http://d-nb.info/111518282X/34.
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Zoldakova, Miroslava [Verfasser], and Rainer [Akademischer Betreuer] Schobert. "Biochemical studies of targeted and bimodal analogues of the natural anticancer compounds combretastatin A-4 and illudin M / Miroslava Zoldakova. Betreuer: Rainer Schobert." Bayreuth : Universität Bayreuth, 2011. http://d-nb.info/1059910357/34.
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Henrot, Serge. "Synthese stereo et enantioselective de beta-hydroxy esters fonctionnalises par voie chimique et par voie microbiologique : application a la preparation de la (-) alpha multistriatine et du r (-) gabob." Paris 6, 1987. http://www.theses.fr/1987PA066428.
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Lacerda, Vander Rocha. "Irradiação gama na pós-colheita dos frutos de pitaya vermelha de polpa branca /." Botucatu, 2020. http://hdl.handle.net/11449/192231.
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Orientador: Rogério Lopes VieitesResumo: A pitaya vermelha de polpa branca é uma fruta que vem conquistando o mercado devido a sua alta aceitação pelos consumidores e seus benefícios para a saúde. Objetivou-se avaliar a conservação pós-colheita dos frutos de pitaya vermelha de polpa branca durante o armazenamento refrigerado, após serem submetidos a diferentes doses de irradiação gama, visando a preservação da qualidade, bem como verificar as alterações no metabolismo secundário quanto aos compostos bioativos, e também identificar o melhor solvente extrator e o melhor peso da amostra, na extração de compostos bioativos e atividade antioxidante dos frutos. Os frutos foram colhidos em um pomar comercial localizado no município de Presidente Prudente-SP, e em seguida transportados para o Departamento de Horticultura da FCA-UNESP. Os frutos embalados foram transportados para o Instituto de Pesquisas Energéticas e Nucleares, onde foram submetidos as doses de irradiação gama. Após, foram armazenados em câmara fria no Departamento de Horticultura, onde foram realizadas as análises físico-químicas da polpa e bioquímicas da casca e polpa dos frutos. O delineamento experimental foi inteiramente casualizado em esquema fatorial 5 x 5, cinco doses de irradiação (0 KGy, 0,3 KGy, 0,6 KGy, 0,9 KGy e 1,2 KGy) e cinco dias de avaliação (zero, 5, 10, 15 e 20 dias). O delineamento para otimização da extração de compostos bioativos e atividade antioxidante foi o inteiramente casualisado com fator único e três repetições. A utilização da... (Resumo completo, clicar acesso eletrônico abaixo)
Abstract: Red pitaya with white pulp is a fruit that has been conquering the market due to its high acceptance by consumers and its health benefits. The objective was to evaluate the postharvest conservation period of the fruits of the red white pulpy pitaya after being subjected to different doses of gamma irradiation, aiming at the preservation of the quality, as well as verifying the alterations in the secondary metabolism regarding the bioactive compounds, and also identify the best extractor solvent and the best weight of the sample, in the extraction of bioactive compounds and antioxidant activity of the fruits. The fruits were harvested in a commercial orchard located in the municipality of Presidente Prudente-SP, and then transported to the Horticulture Department of FCAUNESP. The packaged fruits were transported to the Energy and Nuclear Research Institute, where they were subjected to gamma irradiation doses. Afterwards, they were stored in a cold chamber at the Horticulture Department, where the physical-chemical analyzes of the pulp and biochemical analyzes of the skin and fruit pulp were carried out. The experimental design was completely randomized in a 5 x 5 factorial scheme, five irradiation doses (0 KGy, 0.3 KGy, 0.6 KGy, 0.9 KGy and 1.2 KGy) and five evaluation days (zero, 5, 10, 15 and 20 days). The design for optimizing the extraction of bioactive compounds and antioxidant activity was completely randomized with a single factor and three replications. The use of gam... (Complete abstract click electronic access below)
Mestre
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周厚華 and Donna Chaw. "Biochemical changes in the fermentation bedding of the "pig-on-litter"method of pig farming: with special emphasison biodegradation of nitrogen compounds and odour production." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1996. http://hub.hku.hk/bib/B43893740.
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Liu, Gu. "Target identification and validation studies in chemical biology & Synthesis of medium-sized ring containing compounds via oxidative fragmentation." Thesis, University of St Andrews, 2010. http://hdl.handle.net/10023/986.
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Part I of this thesis describes the development of bioactive small molecules of relevance to the study of the apicomlexan parasite Toxoplasma gondii into useful chemical tools. The research includes the target identification and validation studies, using both chemical and biological methods. Chapter 1 provides an overview of chemical genetics with a particular emphasis on methods for the identification of the protein targets of bioactive small molecules. The concept of biochemical protein target identification techniques was introduced with a detailed discussion of interesting applications from the literature. Chapter 2 focuses on the development of a tetrahydro-β-carboline based lead molecule into a chemical tool through target identification studies. The structure activity relationship (SAR) data associated with this core structure, the design of a chemical inducer of dimerisation (CID) and the synthesis of this CID are discussed in detail. Chapter 3 described work done to identify the potential protein target(s) of Conoidin A. Experiments to assess whether Conoidin A can inhibit a proposed target in vitro are also included. Further optimisation of this structural class to develop more potent inhibitors is discussed in the second part of this chapter. Part II of this thesis describes the development of methods for the synthesis of medium-sized ring containing compounds using oxidative fragmentation and rearrangement strategies. Chapter 5 provides an overview of the existing oxidative fragmentation methodology, with an emphasis on the use of oxidative fragmentation reactions for the synthesis of medium-sized ring systems (8-11 ring atoms). Chapter 6 focuses on using the established oxidative fragmentation method in the oxizino carbazolone system to investigate the diasteroselectivity of this reaction. Possible mechanisms for this transformation are investigated and discussed using both chemical and computational methods. An interesting rearrangement reaction has also been observed during this study. Chapter 7 focuses on developing an asymmetric oxidative fragmentation method, for use in the diazabenz[e]aceathrylenes system. Asymmetric oxidative fragmentation reactions using [Ru(pybox)(pydic)] catalysts are discussed. Attempts to optimise the enantiomeric excesses of the reaction by varying reaction conditions and substituents in the substrate are also included.
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Lee, Yun. "Computational modeling reveals new control mechanisms for lignin biosynthesis." Diss., Georgia Institute of Technology, 2012. http://hdl.handle.net/1853/45774.
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Lignin polymers provide natural rigidity to plant cell walls by forming complex molecular networks with polysaccharides such as cellulose and hemicellulose. This evolved strategy equips plants with recalcitrance to biological and chemical degradation. While naturally beneficial, recalcitrance complicates the use of inedible plant materials as feedstocks for biofuel production. Genetically modifying lignin biosynthesis is an effective way to generate varieties of bioenergy crops with reduced recalcitrance, but certain lignin-modified plants display undesirable phenotypes and/or unexplained effects on lignin composition, suggesting that the process and regulation of lignin biosynthesis is not fully understood. Given the intrinsic complexities of metabolic pathways in plants and the technical hurdles in understanding them purely with experimental methods, the objective of this dissertation is to develop novel computational tools combining static, constraint-based, and dynamic, kinetics-based modeling approaches for a systematic analysis of lignin biosynthesis in wild-type and genetically engineered plants. Pathway models are constructed and analyzed, yielding insights that are difficult to obtain with traditional molecular and biochemical approaches and allowing the formulation of new, testable hypotheses with respect to pathway regulation. These model-based insights, once they are verified experimentally, will form a solid foundation for the rational design of genetic modification strategies towards the generation of lignin-modified crops with reduced recalcitrance. More generically, the methods developed in this dissertation are likely to have wide applicability in similar studies of complex, ill-characterized pathways where regulation occurring at the metabolic level is not entirely known.
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Tontini, Jalise Fabíola. "Produção de cordeiros em pastagem tropical : dos aspectos bioquímicos da pastagem ao comportamento ingestivo animal." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2018. http://hdl.handle.net/10183/180594.
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As pastagens que cobrem uma importante área no território mundial apresentam elevado potencial de produtividade e suas características bioquímicas podem gerar relevante impacto na produção de ruminantes. Porém, poucos trabalhos relatam a concentração de compostos bioquímicos em pastagens tropicais comumente usadas na produção animal. Diante deste fato, o capítulo II desta tese teve como objetivo elucidar e determinar a concentração de taninos condensados e tocoferol, bem como avaliar a produção e os valores nutritivos de espécies forrageiras tropicais normalmente usadas em sistemas de pastejo. Com este estudo foi possível constatar que algumas espécies de gramíneas e leguminosas se destacam não apenas pela sua capacidade de produção de biomassa e qualidade nutricional, mas também pela concentração de compostos bioquímicos, como a gramínea tifton que teve elevada concentração de α-tocoferol (202.3 ± 116.5 mg/kg matéria verde, MV). As leguminosas amendoim forrageiro (15.7 ± 5.2 g/kg matéria seca, MS) e feijão guandu (8.7 ± 0.8 g/kg MS) apresentaram boa concentração de taninos condensados, mas o grande destaque foi para a leguminosa nativa pega-pega (66.5 ± 13.8 g/kg MS) que além da alta concentração de taninos, esses apresentaram potencial para atividade biológica (PPF = 60.1 g/kg MS) Aliado as características bioquímicas, as espécies que irão compor o sistema de produção podem influenciar na biologia de vida livre dos nematoides parasitas do trato gastrintestinal (NGI) e no comportamento ingestivo dos animais. O capítulo III e IV avaliam três diferentes sistemas de alimentação de cordeiros em pastagens tropicais. O capítulo III traz como objetivo avaliar a distribuição de larvas infectantes (L3) em diferentes perfis de pastagem tropical (gramíneas e leguminosas) e o impacto da contaminação da pastagem na carga parasitária e desempenho de cordeiros. Onde, a inclusão da leguminosa tropical alterou a concentração de larvas infectantes na pastagem e a contaminação dos animais. No capítulo IV é apresentado o trabalho que teve como objetivo avaliar o comportamento ingestivo de cordeiros em condições de pastejo contínuo submetidos a diferentes sistemas de alimentação com a presença de leguminosa tropical contendo taninos condensados. Apesar da diferença estrutural e concentração de taninos condensados, de modo geral essas características da pastagem não alteraram o comportamento ingestivo dos cordeiros.Pastures covering an important area in the world territory present high production potential and their biochemical characteristics can generate a significant impact on the production of ruminants. However, few studies report the concentration of biochemical compounds in tropical pastures commonly used in animal production. Facing this fact, chapter II of this thesis had as objective to elucidate and to determine the concentration of condensed tannins and tocopherol, as well as to evaluate the production and nutritional values of tropical forage species normally used in grazing systems. In this study, it was possible to verify that some species of grasses and legumes stand out not only for their mass production capacity and nutritional quality, but also for the concentration of secondary compounds, such as tifton grass, which had a high α-tocopherol concentration (202.3 ± 116.5 mg / kg green matter, GM). The forage peanut legumes (15.7 ± 5.2 g / kg dry matter, DM) and pigeon pea (8.7 ± 0.8 g / kg DM) had an excellent concentration of condensed tannins, but the main highlight was the native legume Desmodium incunum (66.5 ± 13.8 g / kg DM) that in addition to the high concentration of tannins, these had potential for biological activity (PPP = 60.1 g / kg DM) In addition to the biochemical characteristics, the species that will make up the production system can influence the ecology of the free-living stages of endoparasite of the gastrointestinal tract (NGI) and the ingestive behavior of the animals. Chapter III and IV evaluate three different feeding systems of lambs in tropical pastures. Chapter III aims to evaluate L3 distribution in different tropical pasture (grass and legume) profiles and the impact of pasture contamination on lamb parasitic loads and production performance. Where the inclusion of the tropical legume changed the concentration of infective larvae in the pasture and the contamination of the animals. Chapter IV presents the work that aimed to evaluate the ingestive behavior of lambs under continuous grazing conditions submitted to different feeding systems with the presence of tropical legume containing condensed tannins. Despite the structural difference and concentration of condensed tannins, in general these pasture characteristics did not alter the ingestive behavior of the lambs.
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Fouret, Yolande. "Etude in vitro du rajeunissement prealable a la micropropagation chez le sequoia sempervirens (endl. ) : recherche de marqueurs morphologiques, physiologiques et biochimiques." Paris 6, 1987. http://www.theses.fr/1987PA066379.
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En utilisant la technique de culture in vitro, nous nous sommes attaches a etudier les modalites du rajeunissement par des subcultures reiterees d'explants miniaturises chez deuxx clones de sequoia sempervirens issus d'arbres ages de 50 et 500 ans. Le choix du traitement doit etre d'autant plus drastique que le clone est issu d'arbres ages. Parmi les nombreux criteres etudies, nous en avons determine plusieurs permettant de suivre l'evolution du rajeunissement du materiel : la hauteur des tiges, le nombre de feuilles, l'enracinnement ( pourcentage et delai) et la reactivation des meristemes caulinaires isoles
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Dietrich, Guilherme. "Decomposição e liberação de nitrogênio da palha cana-de-açucar em função do ambiente e quantidade de palha." Universidade Federal de Santa Maria, 2014. http://repositorio.ufsm.br/handle/1/5599.
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Coordenação de Aperfeiçoamento de Pessoal de Nível SuperiorThe sugarcane residues came out as an important source of biomass for the production of cellulosic ethanol in Brazil. However, there is a lack of studies on the impact that how partial removal of these residues affect the decomposition of the remaining crop residue on the soil surface. In this context, the aim of this study was to evaluate the decomposition and release of nitrogen (N) from sugarcane residues under field conditions. Three different rates of residues were evaluated at five different location of the Rio Grande do Sul state, Brazil. The study was conducted from September 2012 to August 2013, in the municipalities of Port Xavier, São Luiz Gonzaga, Jacuí Heels, Santa Maria and Pelotas. The experimental design was completely randomized with four replications. To monitor the process of decomposition, RB 956 911 sugarcane straw was air dried, and added in amounts equivalent to 4, 8 and 12 t ha-1 in wooden boxes. These wooden boxes were then collected monthly over a period of one year. The collected materials, was analyzed for the remaining amounts of dry matter (DM) and its C and N concentrations. The straw collected in Santa Maria were also analyzed for hemicellulose (HEM), cellulose (CEL) and lignin (LIG ) the values of DM and remaining C was adjusted in non-linear regression model. The results of this study demonstrated that the amount of sugarcane straw deposited on the surface does not affect the decomposition and release of carbon and nitrogen, and also the breakdown of bio-chemicals (cellulose, hemicellulose and lignin) in the straw. However, it was demonstrated that the site influenced the decomposition and carbon and nitrogen release from the straw, with the main factor controlling decomposition process was precipitation.
Os resíduos culturais da cultura da cana-de-açúcar se destacam como importante fonte de biomassa para a produção do etanol celulósico no Brasil. No entanto, há uma carência de estudos sobre o impacto que a retirada parcial desses resíduos causa na decomposição dos resíduos culturais remanescentes na superfície do solo. Nesse contexto, o objetivo deste estudo foi avaliar a decomposição e liberação de nitrogênio (N) dos resíduos culturais de cana-de-açúcar em condições de campo em função de três diferentes quantidades de resíduos e em cinco ambientes do estado do Rio Grande do Sul, Brasil. O estudo foi realizado no período de setembro de 2012 a agosto de 2013, nos municípios de Porto Xavier, São Luiz Gonzaga, Salto do Jacuí, Santa Maria e Pelotas. O delineamento experimental foi o inteiramente casualizado, com 4 repetições. Para monitorar o processo de decomposição, a palha da cana RB 956911, seca ao ar, foi colocado em quantidades equivalentes a 4, 8 e 12 Mg ha-1 em quadros de madeira telados, os quais foram depositados no interior do canavial e recolhidas mensalmente durante um período de 360 dias. Nos materiais coletados, foram feitas determinações das quantidades remanescentes de matéria seca (MS) e da sua concentração de C e N. Na palha coletada em Santa Maria foram também determinados os teores de hemicelulose (HEM), celulose (CEL) e lignina (LIG) Aos valores obtidos de MS e C remanescentes foi ajustado modelo de regressão não linear. Os resultados deste estudo demonstram que a quantidade de resíduos de cana-de-açúcar depositada na superfície do solo não afeta a decomposição, liberação de carbono e nitrogênio, e também a decomposição dos compostos bioquímicos (celulose, hemicelulose e lignina) presentes na palha. No entanto, foi demonstrado que o local de estudo exerce influência na decomposição e liberação de carbono e nitrogênio dos resíduos, sendo a precipitação o principal fator controlador do processo de decomposição.
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Barbosa, José Carlos Silva. "Distribuição espaço-temporal de hidrocarbonetos de petróleo no estuário do Rio Vaza Barris-SE." Pós-Graduação em Química, 2014. https://ri.ufs.br/handle/riufs/6036.
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The Vaza Barris river estuarine system is located at 11o 08 ´S and 37o 10´ W, at sea level. It has a total area of 115 km2, with a ecosystem with great biological diversity and vegetation composition. Due its great importance in biological and vegetative diversity, it has been inserted in an Environmental Protection area, called EPA. The Vaza Barris river estuarine system has been suffering with human actions, such as recreation and leisure, traffic of maritime vessels, shrimp farming and real estate activities. The present work aims to understand the spatial and temporal distribution of geochemical biomarkers, the Aliphatic Hydrocarbons (AH) and Polycyclic Aromatic Hydrocarbons (PAH) on the superficial sediments of the Vaza Barris river. This work also intends to understand how sedimentary deposition has happened and the importance of this deposition. To conduct this study, samples were collected in two campaigns (Winter and Summer). During the winter, 13 sites were sampled with a triplicate in the station 13 (13a, 13b and 13c). In the summer campaign, it was repeated the 13 sites previous sampled and added two others, giving a total of 15 sites. For the extraction of hydrocarbons from the sediments, it was used Ultrasonic extraction, with dichloromethane as the extraction solvent. In the samples clean-up (alumina and silica), hexane was used for the AH (F1) Fraction elution and dichloromethane/n-hexane (1:1) for the elution of PAH fraction (F2). The analysis was carried out by Gas Chromatography/Mass Spectrometry (GC/MS). To understand the distribution of hydrocarbons, it as used several Diagnostic Index Ratios (DIR). The AH and its isoprenoid (Pristane and Phytane) had good recoveries, wit values between 50.74 and 108.95% and a mean recovery above 60% with relative standard deviation RSD of 18.8%. Their concentrations ranged from 0.19 up to 8.5 Êg.g-1 of dry sediment. The Carbon Preference Index (CPI) calculated for all points (except for VB2 and VB3 in winter) associated with reasons °alifaticos/n-C16 and BMM/AMM (ratio of Low Molecular Weight/High Molecular Weight) suggested biogenic contribution. Their values of RTA (Terrestrial to Aquatic Ratio) and predominance of odd chains and high concentrations of the n-C29 homologue indicated biogenic contribution with significant contribution of higher terrestrial plants. The recoveries of PAH ranged between 45.46 and 163.0% with a mean recovery above 100% and RSD of 28.31%. Their total concentrations ranged from 0.09 a 410.4 ng.g-1 of dry sediment, with levels above the TEL (NOAA) and PQT (Environment Canada). Its DIR indicated a mixture of contributions (petrogenico, pyrolytic and combustion of biomass), with a strong tendency of pyrolytic contribution. Its distribution shows a predominance of high molecular weight compounds, registering significant concentrations for Benzo(a)pyrene, Pyrene, followed by Benzo(b)fluoranthene and Benzo(a)anthracene, both considered mutagenic and carcinogenic. The predominance of pyrolytic contribution may be justified by the existing heavy boat traffic in the estuary.O estuario do Rio Vaza Barris esta situado a 11o 08 f S e 37o 10 f O ao nivel do mar com area total de 115 km2, apresenta grande diversidade biologica e vegetativa e esta inserida em uma Area de Protecao Ambiental (APA). O estuario do Rio Vaza Barris vem sofrendo diferentes tipos de acoes antropicas: atividades de recreacao e lazer, intenso trafego de embarcacoes maritimas, cultivo de camarao em viveiros e tanques, desmatamento com possiveis queimadas e especulacao imobiliaria. Desta forma o presente trabalho visa compreender a distribuicao espaco-temporal dos marcadores geoquimicos, Hidrocarbonetos Alifaticos (HA) e Hidrocarbonetos Policiclicos Aromaticos (HPA), no sedimento superficial do estuario do Rio Vaza Barris, o processo de deposicao sedimentar, assim como o aporte e o impacto causado. Para o desenvolvimento do presente estudo, foram realizadas coletas em duas estacoes, (Inverno e Verao), no inverno foram 13 pontos com uma triplicata no ponto 13 (13a, 13b e 13c), no verao foram repetidos os 13 pontos anteriores e foram acrescentados outros dois, totalizando 15 pontos. Para a extracao dos hidrocarbonetos em sedimento, foi utilizada a extracao assistida por ultrassom tendo diclorometano como solvente de extracao. No clean-up (silica e alumina), foi utilizado n-Hexano para a eluicao da fracao de HA (F1) e diclorometano/n-hexano 1:1 para a eluicao da fracao de HPA (F2). As analises foram realizadas por Cromatografia a Gas/Espectrometria de Massas (GC-MS). Para a compreensao da distribuicao desses hidrocarbonetos na regiao, foram considerados alguns Indices de Razao Diagnostica (IRD). Os HA e seus isoprenoides (Pristano e Fitano) apresentaram recuperacoes entre 50,74 e 108,95% com recuperacao media acima de 60% e desvio padrao relativo RSD de 18,8%. Suas concentracoes variaram entre 0,19 Êg.g-1 a 8,5 Êg.g-1 de sedimento seco. O Indice Preferencial de Carbono (IPC) calculado para todos os pontos (exceto para VB2 e VB3 no inverno) associado as razoes °alifaticos/n-C16 e BMM/AMM (razao de Baixa Massa Molecular/Alta Massa Molecular) sugeriu aporte biogenico. Seus valores de RTA (Razao Terrestre Aquatica) e predominancia das cadeias impares e do homologo n-C29 indicaram aporte biogenico com significativa contribuicao de plantas terrestre superiores. As recuperacoes dos HPA variaram entre 45,46 e 163,0% com recuperacao media acima de 100% apresentando RSD de 28,31%. Suas concentracoes totais variaram entre 0,09 ng.g-1 a 410,4 ng.g-1 de sedimento seco, registrando niveis de concentracao acima do TEL (NOAA) e PQT (Environment Canada). Seus IRD indicaram uma mistura de aportes (petrogenico, pirolitico e de combustao de biomassa), com predominancia para o aporte pirolitico. Sua distribuicao mostra predominancia de compostos de alta massa molecular, registrando concentracoes expressivas para Benzo(a)pireno, Pireno, seguido do Benzo(b)fluoranteno e Benzo(a)antraceno, ambos considerados mutagenicos e carcinogenicos. A predominancia do aporte pirolitico pode ser justificada, por existir intenso trafego de embarcacoes no estuario e por ser uma regiao turistica.
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Essandoh, Helen M. K. "Efficiency of soil aquifer treatment in the removal of wastewater contaminants and endocrine disruptors. A study on the removal of triclocarban and estrogens and the effect of chemical oxygen demand and hydraulic loading rates on the reduction of organics and nutrients in the unsaturated and saturated zones of the aquifer." Thesis, University of Bradford, 2011. http://hdl.handle.net/10454/5710.
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This study was carried out to evaluate the performance of Soil Aquifer Treatment
(SAT) under different loading regimes, using wastewater of much higher strength
than usually encountered in SAT systems, and also to investigate the removal of the
endocrine disruptors triclocarban (TCC), estrone (E1), 17¿-estradiol (E2) and 17¿-
ethinylestradiol (EE2). SAT was simulated in the laboratory using a series of soil
columns under saturated and unsaturated conditions.
Investigation of the removal of Chemical Oxygen Demand (COD), Biochemical
Oxygen Demand (BOD), Dissolved Organic Carbon (DOC), nitrogen and phosphate
in a 2 meter long saturated soil column under a combination of constant hydraulic
loading rates (HLRs) and variable COD concentrations as well as variable HLR
under constant COD showed that at fixed HLR, a decrease in the influent
concentrations of DOC, BOD, total nitrogen and phosphate improved their removal
efficiencies. It was found that COD mass loading applied as low COD wastewater
infiltrated over short residence times would provide better effluent quality than the
same mass applied as a COD with higher concentration at long residence times. On
the other hand relatively high concentrations coupled with long residence time gave
better removal efficiency for organic nitrogen. Phosphate removal though poor under
all experimental conditions, was better at low HLRs.
In 1 meter saturated and unsaturated soil columns, E2 was the most easily removed
estrogen, while EE2 was the least removed. Reducing the thickness of the
unsaturated zone had a negative impact on removal efficiencies of the estrogens
whereas increased DOC improved the removal in the saturated columns. Better
removal efficiencies were also obtained at lower HLRs and in the presence of silt
and clay.
Sorption and biodegradation were found to be responsible for TCC removal in a 300
mm long saturated soil column, the latter mechanism however being unsustainable.
TCC removal efficiency was dependent on the applied concentration and decreased
over time and increased with column depth. Within the duration of the experimental
run, TCC negatively impacted on treatment performance, possibly due to its
antibacterial property, as evidenced by a reduction in COD removals in the column.
COD in the 2 meter column under saturated conditions was modelled successfully
with the advection dispersion equation with coupled Monod kinetics. Empirical
models were also developed for the removal of TCC and EE2 under saturated and
unsaturated conditions respectively. The empirical models predicted the TCC and
EE2 removal profiles well. There is however the need for validation of the models
developedNetherlands Organisation for International Cooperation in Higher Education (Nuffic)
The Appendix files for this thesis are unavailable online via Bradford Scholars.
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Essandoh, Helen Michelle Korkor. "Efficiency of soil aquifer treatment in the removal of wastewater contaminants and endocrine disruptors : a study on the removal of triclocarban and estrogens and the effect of chemical oxygen demand and hydraulic loading rates on the reduction of organics and nutrients in the unsaturated and saturated zones of the aquifer." Thesis, University of Bradford, 2011. http://hdl.handle.net/10454/5710.
Full textAbstract:
This study was carried out to evaluate the performance of Soil Aquifer Treatment (SAT) under different loading regimes, using wastewater of much higher strength than usually encountered in SAT systems, and also to investigate the removal of the endocrine disruptors triclocarban (TCC), estrone (E1), 17β-estradiol (E2) and 17α-ethinylestradiol (EE2). SAT was simulated in the laboratory using a series of soil columns under saturated and unsaturated conditions. Investigation of the removal of Chemical Oxygen Demand (COD), Biochemical Oxygen Demand (BOD), Dissolved Organic Carbon (DOC), nitrogen and phosphate in a 2 meter long saturated soil column under a combination of constant hydraulic loading rates (HLRs) and variable COD concentrations as well as variable HLR under constant COD showed that at fixed HLR, a decrease in the influent concentrations of DOC, BOD, total nitrogen and phosphate improved their removal efficiencies. It was found that COD mass loading applied as low COD wastewater infiltrated over short residence times would provide better effluent quality than the same mass applied as a COD with higher concentration at long residence times. On the other hand relatively high concentrations coupled with long residence time gave better removal efficiency for organic nitrogen. Phosphate removal though poor under all experimental conditions, was better at low HLRs. In 1 meter saturated and unsaturated soil columns, E2 was the most easily removed estrogen, while EE2 was the least removed. Reducing the thickness of the unsaturated zone had a negative impact on removal efficiencies of the estrogens whereas increased DOC improved the removal in the saturated columns. Better removal efficiencies were also obtained at lower HLRs and in the presence of silt and clay. Sorption and biodegradation were found to be responsible for TCC removal in a 300 mm long saturated soil column, the latter mechanism however being unsustainable. TCC removal efficiency was dependent on the applied concentration and decreased over time and increased with column depth. Within the duration of the experimental run, TCC negatively impacted on treatment performance, possibly due to its antibacterial property, as evidenced by a reduction in COD removals in the column. COD in the 2 meter column under saturated conditions was modelled successfully with the advection dispersion equation with coupled Monod kinetics. Empirical models were also developed for the removal of TCC and EE2 under saturated and unsaturated conditions respectively. The empirical models predicted the TCC and EE2 removal profiles well. There is however the need for validation of the models developed
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Rehmann, Lars. "Delivery of hydrophobic substrates to degrading organisms in two-phase partitioning bioreactors." Thesis, Kingston, Ont. : [s.n.], 2007. http://hdl.handle.net/1974/506.
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Lima, Antonio William Oliveira. "Desenvolvimento de métodos analíticos em sistemas de soluções em fluxo empregando polifenol oxidase naturalmente imobilizada sobre tecidos vegetais." Universidade de São Paulo, 1998. http://www.teses.usp.br/teses/disponiveis/46/46133/tde-29082008-103749/.
Full textAbstract:
Esta tese apresenta o desenvolvimento de metodologias analíticas em sistemas de solução em fluxo com detecção amperométrica e espectrofotométrica explorando a utilização de tecidos vegetais como fonte enzimática para a biocatálise de reações. Desempenhos satisfatórios foram obtidos com a utilização do mesocarpo fibroso do coco (Cocus nucifera, L.) e com a casca e/ou polpa de frutos da palmeira leque (Latania sp), fontes de polifenol oxidase. Uma metodologia, simples e rápida, para a determinação dos parâmetros bioquímicos da polifenol oxidase foi desenvolvida ao longo do presente trabalho com a enzima naturalmente imobilizada no tecido do coco, pela eliminação das etapas de extração e de purificação e associando-se análise em fluxo e espectrofotometria. Parâmetros cinéticos importantes como o efeito do pH, a constante de Michaelis-Menten (Km), a velocidade máxima (Vmax),a energia de ativação (Ea) e os parâmetros térmicos (valores D, z e Q10)foram determinados utilizando como substrato o catecol. A atividade relativa junto a diferentes substratos e o efeito de inibidores foram também avaliados. Aplicações envolvendo estes tecidos vegetais em reatores empacotados (associados com FIA) ou incorporados em eletrodos de pasta de carbono (medidas realizadas em batelada) para a determinação de produtos fenólicos como catecol, fenol e dopamina, inibidores da atividade enzimática como o sulfito, bem como para a quantificação do conteúdo de água, demonstram a sua versatilidade. Os produtos fenólicos foram quantificados com boa sensibilidade (na faixa de µmol L-1) pela redução amperométrica das respectivas quinonas, produzidas pela oxidação enzimática. Aplicações com amostras reais, dentre as quais água de rio e resíduos de uma fábrica de papel puderam ser implementadas. A determinação do conteúdo de água em meio aquo-restrito explorou a estimulação, pela água, da atividade catalitica da polifenoI oxidase naturalmente imobilizada no mesocarpo fibroso do coco na presença de catecol. Esta propriedade foi utilizada para a determinação rápida e reprodutível do conteúdo de água em amostras comerciais de álcool, utilizando acetonitrila como carregador. A quantificação de sulfito baseou-se no seu efeito inibidor sobre a polifenol oxidase naturalmente imobilizada em relação à catálise oxidativa do catecol. Diversos interferentes comumente presentes em amostras de vinho foram também investigados. Durante este trabalho, foi desenvolvida uma simples e interessante maneira de conservar o mesocarpo fibroso do coco como fonte de polifenol oxidase naturalmente imobilizada. O tecido desta fruta foi desidratado e moído. O pó deste tecido, estocado a mais de dois anos à temperatura ambiente, ainda apresenta boa atividade enzimática.The development of analytical methodologies exploring plant tissues as enzymatic source for biocatalysis of many reactions is presented in this thesis. Amperometry and spectrophotometry was associated with flow analysis for analytical purposes and for biochemical characterization of naturally immobilized polyphenol oxidase. Good performance was achieved with tissues from the fruits of two palm trees: the fibrous mesocarp of green coconut fruits, Cocus nucifera, L., and the skin and the pulp of green fruits from Latania sp. Both tissues are very effective in the biotransformation of o-diphenols to the corresponding o-quinones. A simple, fast, and new methodology for the determination of the biochemical parameters of the poyphenol oxidase naturally immobilized on the fibrous tissue was developed (eliminating the extraction and purification of enzymes) by association of flow injection analysis and spectrophotometry. For coconut tissue, cinetic parameters like pH effect, Michaelis-Menten constant (Km) and maximum rate (Vmax), activation energy (Ea) and thermal parameters (D, z and Q10values) on catechol biotransformation were determined. Also the response for several substrates as too for various inhibitors was explored. Amperometric quantification of phenolic compounds was made using the vegetal tissue in form of packed reactors (associated with FIA) or incorporated in carbon paste electrodes (measurements in batch). Very good response for catechol, phenol and dopamine was registered for this compounds, with very high sensitivity (µmol L-1 range). Applicability to real samples as for river water and for a paper plant waste water was verified. The same amperometry-FIA system was employed for enzymology in non-aqueous medium. The activity of the polyphenol oxidase contained in coconut tissues are strongly dependent of water. The strategy involves the stimulation by the content of water on the biocatalytic activity of the enzyme in the presence of catechol substrate. This strategy was used for the determination of water content in alcohol samples, in medium of dry acetonitrile. The inhibition of the enzymatic activity produced by many compounds can be explored for an indirect quantification of the inhibitor. A flow injection amperometric procedure was developed for the determination of sulphite ion based in its inhibitory effect on the activity of polyphenol oxidase on the oxidation of catechol. The effect on the bioreactor performance of potential interferents commonly present in wine samples were also investigated. During this work, it was developed a simple and interesting way to preserve coconut tissue. The mesocarp of this fruit can be dried and grounded. These tissues still with very good activity after more than two years in \"shelf temperature\".
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Zaiter, Ali. "Étude de la phytochimie de 12 plantes de la région Lorraine en fonction de la granulométrie de poudres superfines." Thesis, Université de Lorraine, 2017. http://www.theses.fr/2017LORR0012/document.
Full textAbstract:
Ce projet porte sur l’étude de plusieurs plantes d’intérêt de la Lorraine afin d’extraire par voie sèche et d’analyser des substances bioactives pour une valorisation de la flore locale. Un procédé de broyage et de tamisage de matériel végétal en de fines particules est utilisé afin de concentrer les composés bioactifs dans les poudres résultantes. Les poudres présentent des tailles de particules allant de 20 µm à 500 µm. Les propriétés phytochimiques de chaque classe granulométrique sont comparées à celle des parties de plantes non tamisées. Ces activités sont liées aux métabolites secondaires notamment les polyphénols et les dérivés terpéniques, qui sont caractérisés et quantifiés par des analyses LC-MS et GC-MS. Au cours de ce travail ont été développés : - la validation d’une nouvelle technique de séparation différentielle en fonction de la granulométrie des poudres par comparaison avec des extraits de plantes non tamisées ; - le dosage des différents constituants chimiques par des méthodes spectrométriques (UV/Visible), la caractérisation par des techniques analytiques telles que la LC-MS et GC-MS ; - l’évaluation du potentiel antioxydant/anti-radicalaire et anti-acétylcholinestérase réalisée par voie chimique in vitro en fonction des classes granulométriques. Cette étude démontre l’intérêt que présente ce nouveau procédé d’extraction différentiel des composés bioactifs issue de matrices végétales. Un enrichissement en produits actifs est observé au niveau de certaines classes granulométriques. Au niveau des activités antioxydantes pour toutes les plantes et de l’activité anti-acétylcholinestérase dans le cas du saule blanc, on observe des variations significatives en fonction de la taille de particules des échantillons des poudres superfines. L’étude de l’activité anti-acétylcholinestérase a été complétée par une modélisation in silico afin de mettre en évidence l’interaction entre les composés et les sites actifs de l’enzyme acétylcholinestéraseThis project focuses on the study of 12 plants coming from Lorraine region. The study aims to improve the exploitation of local flora using a dry extraction process. A milling and a sieving process up to fine particles of plant material is used to concentrate the bioactive compounds in the resulting powders. The powders were classified according to the particle size which were ranging from 20 µm to 500 µm. The phytochemical properties of each particle size fraction are compared to non-sieved plant parts. These activities are linked to secondary metabolites including polyphenols and terpene derivatives, which are characterized and quantified by LC-MS and GC-MS analyses. It was developed in this work a new validation technique of differential separation depending on the particle size of the powders compared with extracts of non-sieved plant parts. The quantification of chemical compound classes was done by UV-Visible methods and their identification was conducted using LC-PDA/MS and GC-MS characterization technics. The evaluations of the antioxidant activity and anti-acetylcholinesterase activity is carried out in vitro according to the particle sizes. This study demonstrates the usefulness of this new differential extraction process of bioactive compounds from vegetal matrices. The Enhancing of the concentration of the active products is observed according to the particle sizes. In silico modeling study of anti-acetylcholinesterase activity is employed to highlight the interactions between the active sites and some anticipated active compounds in the extract
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Nguyen, Vinh Xuan. "Mecanismes de la resistance au gel de l'embryon de pommier (pyrus malus l. Cv. Golden delicious)." Paris 6, 1987. http://www.theses.fr/1987PA066554.
Full textAbstract:
Des pommes (pyrus malus l. Cv. "golden delicious" ont ete entreposees apres la recolte, a 0,12 et 35**(o)c. Apres 4 semaines, des lots de fruits ont ete transferes de 0 a 12**(o)c ou inversement de 12 a 0**(o)c. Les basses temperatures (0**(o)c) favorisent la levee de dormance, tandis que les temperatures elevees (12 et 35**(o)c) sont favorables a une meilleure resistance au gel et ces 2 phenomenes sont independants. L'analyse thermique differentielle a montre que l'embryon de pommier ne peut survivre au gel qu'en evitant la congelation intracellulairegrace a une surfusion prolongee. Plus la temperature de conservation des fruits est elevee, plus la temperature de surfusion est basse
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Tremblay-Boeuf, Valérie. "Effets des contraintes mécaniques sur l'exsudation racinaire du maïs." Vandoeuvre-les-Nancy, INPL, 1995. http://www.theses.fr/1995INPL079N.
Full textAbstract:
Ce travail a permis d'évaluer les effets de la contrainte mécanique sur l'exsudation racinaire du maïs (Zea mays l. , variété Dea) et d'examiner l'importance de ces effets en relation avec le stade de développement de la plante. La culture des plantes a été conduite en conditions stérile et hydroponique. La contrainte mécanique a été simulée à deux niveaux d'intensité, à l'aide de billes de verre de 1 et 4 mm de diamètre. Ces traitements ont été comparés à un témoin sans billes. Les résultats ont montré que la croissance de la plante est influencée par la contrainte mécanique. Cette dernière affecte de façon notable la croissance des parties aériennes, aussi bien la surface foliaire que la matière sèche totale, ainsi que la morphologie du système racinaire. L’application de la contrainte mécanique est également responsable de la stimulation de l'exsudation de composés organiques et inorganiques. En outre, la prise en compte du matériel adhérant au support des racines revêt un rôle essentiel dans l'estimation quantitative de l'exsudation racinaire. En effet, des quantités non négligeables de mucilages racinaires ont été déterminées sur les billes de verre. Les résultats obtenus à partir d'analyses biochimiques, appuyés par des études utilisant les méthodes de marquage isotopique du carbone, démontrent que les plantes stressées ont libéré davantage de composés carbones que les plantes témoins. Selon le stade de développement de la plante, les effets de la contrainte mécanique sont d'ampleur différente et semblent s'amplifier avec la durée de culture. La confrontation de ces résultats avec les données obtenues au champ a confirmé ces tendances et les limites du modèle utilisé ont été définies
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Dibos, Chloé. "Interactions plante - pollinisateur : caractérisation de la qualité du pollen de deux cucurbitacées durant son ontogenèse, sa présentation et son transport sur le corps de l'abeille domestique." Phd thesis, Université d'Avignon, 2010. http://tel.archives-ouvertes.fr/tel-00587581.
Full textAbstract:
Chez de nombreuses Angiospermes, la pollinisation croisée est nécessaire pour le succès de la reproduction. La plupart de ces plantes ont évolué afin de favoriser la pollinisation entomophile, principalement assurée par les abeilles. C'est le cas des Cucurbitacées, dont le melon (Cucumis melo L.), importante culture du sud de la France et le concombre d'âne (Ecballium elaterium (L.) A. Rich.) plante spontanée endémique du bassin méditerranéen, les deux modèles de cette étude. Afin de mieux comprendre les relations plante-pollinisateur,nous avons choisi de caractériser le couple pollen de Cucurbitacées/abeille domestique (Apis mellifera L.) à travers la production de pollen, sa présentation sur la fleur et son transport sur l'abeille. Nous avons montré que, chez ces plantes, l'ontogenèse du pollen s'accompagne d'erreurs développementales conduisant à la formation de près de 3% de grains de pollen vides. De plus, nous avons mis en évidence que chez E. elaterium, des erreurs méiotiques entraînaient la formation de grains de pollen génétiquement anormaux qui pourraient être source d'autopolyploïdie. Chez C. melo, nos résultats ont révélé que la mise en contact du pollen avec le milieu environnant entraîne une baisse de 30% de sa viabilité, mais que celle-ci reste stable jusqu'à la fin de l'anthèse. L'aptitude à germer, quant à elle, finit d'être acquise juste avant anthèse et décroît de 12% en fin de période d'anthèse. Nous avons montré que le pollen de C. melo transporté sur le corps de l'abeille pouvait soit avoir une viabilité et une aptitude à germer préservée, probablement par protection contre la déshydratation, soit perdre quasi-totalement sa viabilité et son aptitude à germer. Enfin, nous avons détecté des composés biochimiques spécifiques des abeilles protégeant ou diminuant la qualité reproductrice du pollen
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Safa, Hassan. "Réduction combinée en chlorure de sodium et en matière grasse animale lors de la fabrication du saucisson sec : effets sur les propriétés physicochimiques et les réactions biochimiques en lien avec la production aromatique et les attributs sensoriels." Thesis, Clermont-Ferrand 2, 2016. http://www.theses.fr/2016CLF22668/document.
Full textAbstract:
Du fait de problèmes de santé publique, l’industrie agroalimentaire doit réduire la quantité de sel et de matière grasse dans les aliments, et donc dans les charcuteries. Lors de la fabrication des saucissons secs, une diminution combinée des taux de sel et de matière grasse animale peut se traduire par des problèmes de stabilité microbiologique, des défauts d’arôme et de texture dus à des modifications physicochimiques et biochimiques. Dans ce contexte, les objectifs de cette thèse étaient : (1) d’étudier l’impact d’une réduction directe des teneurs en sel et en matière grasse animale sur les évolutions physicochimiques et biochimiques au sein des produits, (2) d’identifier les composés aromatiques responsables de l’arôme du saucisson sec, ainsi que leurs origines, (3) de développer de nouvelles formulations de saucissons secs à teneurs réduites en sodium et en acides gras saturés, et (4) d’étudier les transferts d’eau et sel et de développer une isotherme de sorption spécifique pour le saucisson sec. L’étude de l’effet d’une réduction directe combinée a mis en évidence la difficulté de fabriquer des saucissons secs à teneurs réduites en sel et en matière grasse animale, sans modifier les évolutions physicochimiques et biochimiques. Une identification des composés volatils odorants de saucissons secs de haut de gamme a permis de montrer que l’aromatisation par l’ail et le poivre noir pouvait être un levier technologique permettant d’améliorer la qualité aromatique des saucissons secs allégés en sel et en matière grasse animale. L’impact de l’aromatisation et d’une substitution partielle combinée du sel par le chlorure de potassium et du gras de bardière de porc par l’huile de tournesol oléique sur les propriétés physicochimiques, les réactions biochimiques et les attributs sensoriels de saucissons secs, a été étudié. Cette étude a montré le rôle important de l’aromatisation qui agit en introduisant des molécules aromatiques qui rehaussent l’acceptabilité des produits par les consommateurs, en tant qu’exhausteur de la perception du goût salé et aussi, sur les processus fermentaires qui vont conditionner l’aspect et la texture finale du produit. La substitution partielle combinée est une solution efficace pour conserver au mieux la qualité organoleptique des saucissons, en permettant, d’une part, d’éviter les défauts texturaux et sensoriels liés aux modifications physicochimiques, protéolytiques et lipolytiques générés par une réduction directe combinée, et d’autre part, d’améliorer l’arôme du produit en rehaussant les niveaux d’oxydations lipidique et protéique. L’étude des transferts d’eau et de sel a mis en évidence une migration du sel vers le cœur du saucisson, et a permis de déterminer des valeurs de diffusivité apparente de l’eau en surface de ces produits. Il a été montré qu’une forte réduction en matière grasse réduisait la diffusivité de l’eau à la surface du saucisson. Une isotherme de sorption spécifique permettant de prédire l’aw en fonction des teneurs en eau, en lipides et en sel a été construite en adaptant un modèle de Ross établi pour la gélatine salée et grasseBecause of public health problems, the food industry must lower sodium and animal fat contents in all food products, therefore in cured meat products. During dry-fermented sausage manufacture, a combined reduction both in salt and animal fat contents may induce microbial safety problems and textural and aroma defects due to physical-chemical and biochemical changes. On account of that, this work of thesis aims (1) to investigate the impact of a direct reduction on the salt and animal fat contents on the physical-chemical and biochemical evolutions in the products, (2) to identify the aromatic compounds responsible for the aroma of dry-fermented sausage, and their origins, (3) to develop new nutritionally-improved formulations of dry-fermented sausages with less sodium and saturated fatty acids, and (4) to study the impact of lipid and sodium chloride contents on water transfers in dry-fermented sausages and to build a specific sorption isotherm curve for dry sausages. The study of the effect of a combined direct reduction highlighted the difficulty of manufacturing sodium-reduced fat-reduced dry sausages, without affecting the physical-chemical and biochemical evolutions. Identification of odorous volatile compounds of high quality dry sausages showed that flavouring, especially garlic and black pepper, could be a good solution for improving the aromatic quality of salt-reduced fat-reduced dry-fermented sausages. The impact of flavouring and of a combined salt and animal fat replacement by potassium chloride and oleic sunflower oil, respectively, on physical-chemical properties, biochemical reactions and sensory attributes of dry-fermented sausages was then studied. This specific study showed the crucial role played by flavouring which introduces aromatic molecules that enhance the product acceptability by consumers, which acts as an enhancer of the saltiness perception and which improves the product appearance and texture by boosting the fermentation process. Consequently, the combined partial substitution is an efficient solution to preserve at best the organoleptic quality of the products, allowing, on one hand, avoiding the textural and sensory defects related to physical-chemical, proteolytic and lipolytic modifications induced by a combined direct reduction, and on the other hand, enhancing the product aroma by increasing the levels of lipid and protein oxidations. The study on water and salt transfers highlighted a salt diffusion towards the dry sausage core, and made it possible to determine values of apparent water diffusivity at the sausage surface. We demonstrated that a strong reduction in animal fat content significantly lowered the water diffusivity value at the product surface. A specific sorption isotherm curve based on a modified Ross model was built, allowing dry-fermented sausages water activity to be calculated as a function of water, fat and salt contents
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Peng, Ya-Yu, and 彭雅鈺. "Dye containing MWCNTs hybrid films for the determination of hydrogen peroxide and biochemical compound." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/y7rwvr.
Full textAbstract:
碩士國立臺北科技大學
化學工程研究所
98
Part I：I：A novel amperometric biosensor for the analytical determination of hydrogen peroxide was developed. The fabrication of the biosensor was based on the coimmobilization of horseradish peroxidase (HRP), nile blue and multiwalled carbon nanotubes with in ormosils; 3-aminopropyltrimethoxysilane (APTMOS), 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane (ETMOS) and phenyltrimethoxysilane (PHTMOS).The classical redox dye Nile blue and Peroxidase (HRP) were coimmobilized into the multi wall carbon nanotoubes (MWCNTs) modified ormosil matrix. Nafion was dispersed into the ormosil film to enhance the rate of the electron transfer. EETMOS group in ormosil film improves the mechanical strength. APTMOS group provides biocompatible for theimmobilization of enzymes. The surface morphology of MWCNTs/NB/NAF/HRP composite. The ormosil modified electrodes were characterized with Scanning electron microscopy(SEM), Atomic force microscopy (AFM) and Cyclic voltammetry demonstrated the NB coimmobilized with HRP in this way, displayed good stability and could efficiently shuttle electrons between immobilized enzyme and electrode.The facile procedure of immobilizing HRP and MWCNTs into the ormosils film . The optrmun biosensor had a fast response of H2O2 , and excellent linear range of concentration from 2x10-7 to 3.8x10-4 M with the detection limit of 1x10-7 M under the optimum conditions. At the same time, the influence of solution pH, effect of enzyme amount, steady-state applied potential on the biosensor was investigated. The preparation of the developed biosensor was convenient and showed high sensitivity with good stability. Part II：A biosensor for the detection of hydrogen peroxide has been developed. A cationic dye brilliant Cresy Blue (BCB) and horseradish peroxidase (HRP) were coimmobilzed within ormosils on multiwalled carbon nanotabes modified glassy carbon electrode. The feature of biosensor is highly sensitive, fast responding and stable.EETMOS group in ormosils dispersed the mechanical strength of the flim . APTMOS group provides biocompatible for the immobilization of horseradish peroxidase (HRP).The presence of MWCNTs improved the conductivity of the film. The ormosil modified electrodes .The Scanning electron microscopy (SEM), Atomic force microscopy (AFM) and Cyclic voltammetry demonstrated the BCB coimmobilized with HRP in this way, displayed good stability and could efficiently shuttle electrons between immobilized enzyme and electrode. the influence of solution pH, effect of enzyme amount, steady-state applied potential on the biosensor was investigated. The preparation of the developed biosensor was convenient and showed high sensitivity with good stability.The proposed H2O2 biosensor exhibited wide linear range form 3x10-7 to 1x10-4 M and low detection limit of 1x10-7 M. Part III：A novel biocomposite film MWCNTs/NAF /AR was investigated. This Multi-wall carbon nanotubes (MWCNTs) aling with the incorporation of Nafion and Alizarin Red has been synthesized on glassy carbon electrode and gold electrode by potentiostatic methods. The biocomposite film also exhibits a promising enhanced electrocatalytic activity towards the oxidation of biochemical compounds as serotonin and melatonin.The cyclic voltammetry has been used for the measurement of electroanalytical properties of analytes by means of biocomposite film modified gold electrodes.The chronoamperometry has been used for the amperomtric detection of analytes at MWCNTs/NAF/AR modified film electrocatalytic behavior towards reduction of serotonin in the linear range of 1.5×10–6 to 1.5×10–4 M and the detection limit is 1 ×10–4 M, and melatonin in the linear range of 2.5×10–6 to the 1.5×10–4 M and detection limit is 1 ×10–7 M.