In this work, the [3,3] sigmatropic rearrangement of different substituted propargyl thiocyanates and double [3,3] sigmatropic rearrangement of enynyl isothiocyanates either by flash vacuum pyrolysis or by thermolysis in solution are studied. Additionally, the intramolecular reactions of the resulting allenyl isothiocyanates are studied, and the reaction mechanisms for the generation of the final products, such as [1,5] sigmatropic migrations or electrocyclic ring closures, are explained. These highly reactive allenyl isothiocyanates are used as appropriate electrophilic precursors for the preparation of novel examples of thiazoles substituted at C-2 position using different types of nucleophiles. For the formation of these substituted thiazoles, the necessary nucleophilicity as well as the regioselectivity, the stereoselectivity, and the reaction mechanisms are investigated. / In der vorliegenden Arbeit sind die [3,3]-sigmatrope Umlagerung von verschiedenen Propargylthiocyanaten und die doppelte [3,3]-sigmatrope Umlagerung von Eninylisothiocyanaten entweder durch Blitzvakuumthermolyse oder Thermolyse in Lösung untersucht worden. Zusätzlich wurden die intramolekularen Reaktionen der resultierten Allenylisothiocyanate studiert. Außerdem sind die Reaktionsmechanismen zur Bildung der Thermolyseprodukte wie z.B. die [1,5]-sigmatropen Umlagerungen und die elektrocyclischen Ringschlüsse erklärt. Die hochreaktiven Allenylisothiocyanate sind als geeignet elektrophile Vorläufer zur Synthese von neuen Thiazolen verwendbar, die an der C-2 Position substituiert sind. Dabei kommen verschiedene Nucleophile zum Ansatz. Für die Bildung dieser substituierten Thiazole sind die Regioselektivität, Stereoselektivität, Reaktionsmechanismen und der Bereich der einsetzbaren Nucleophile untersucht worden.

京都大学 / 0048 / 新制・論文博士 / 博士(農学) / 乙第12936号 / 論農博第2816号 / 新制||農||1033(附属図書館) / 学位論文||H27||N4895(農学部図書室) / 32146 / (主査)教授 伏木 亨, 教授 保川 清, 教授 安達 修二 / 学位規則第4条第2項該当 / Doctor of Agricultural Science / Kyoto University / DFAM

Since 2006 there have been four Salmonella enterica and one Listeria monocytogenes foodborne outbreaks linked to whole cantaloupe fruit. No post-harvest intervention to reduce potential contamination on cantaloupe currently exists. The complex surface topography of netted cantaloupes aids bacterial attachment. This research evaluates the use of allyl isothiocyanate (AITC; a natural antimicrobial) to reduce populations of S. enterica Michigan and L. monocytogenes on the surface of cantaloupe. Fifty μl of S. Michigan or L. monocytogenes was inoculated onto whole ‗Athena‘ or ‗Hales Best Jumbo‘ (‗HBJ‘) cantaloupe fruit in 22 mm diameter circles and allowed to dry for 90 min. resulting in 6.60 log CFU/g. Cantaloupe received either AITC liquid or vapor, sterile deionized water, 200 ppm sodium hypochlorite per circle, or no treatment. All cantaloupes were stored in separate sealed glass desiccators for 1 or 24 h at 25°C or 35°C. To enumerate the bacteria following treatment, 22 mm sections of the rind were removed, homogenized and plated onto appropriate agar. Headspace analysis using Gas Chromatography-Mass Spectrometry (GC-MS) quantified the concentration of each AITC vapor treatment. The texture quality of the pericarp tissue of whole cantaloupes was evaluated after 24 h treatments, followed by two weeks of storage at 4°C. The concentration of vapor ranged from 3.4 to 19.6 μl AITC/L inside the desiccators. The liquid treatment reduced (P < 0.05) S. Michigan populations on ‗Athena‘ (3 log CFU/g) and L. monocytogenes on ‗HBJ‘ (2.6 log CFU/g). The longer exposure time to the AITC vapor (24 h versus 1 h) resulted in a greater reduction of both S. Michigan and L. monocytogenes on ‗Athena‘ and treatments at 35°C reduced microbial populations up to 4.5 times greater (P < 0.05). The highest vapor concentration reduced (P < 0.05) both pathogens at least 3.0 log CFU/g on ‗Athena‘ at 25°C. Generally, bacterial pathogens from the surface of ‗Athena‘ cantaloupe were reduced more than pathogens inoculated on the surface of ‗HBJ.‘ The application of AITC liquid or vapor is a natural alternative post-harvest treatment to 200 ppm free chlorine to reduce the level of bacterial contamination on cantaloupe surfaces for certified organic production. / Ph. D.

L'induction par un hôte d'un stress oxydatif chez un parasite représente l'une des stratégies de défense chimique les plus répandues. Chez les Brassicacées, famille de plantes comprenant des espèces à fort intérêt agronomique comme le chou ou le colza, ou d'intérêt scientifique comme Arabidopsis thaliana, le stress oxydatif peut être généré soit par des formes actives d'oxygène libérées au niveau de la zone d'agression lors du burst oxydatif soit par des molécules issues du métabolisme secondaire de la plante telles que les isothiocyanates (ITC). Bien que fortement exposé à un tel stress lors de l'infection, Alternaria brassicicola, champignon pathogène nécrotrophe inféodé aux Brassicacées, est capable d'accomplir son cycle parasitaire et donc de s'y adapter. Cette thèse met en évidence que la tolérance du champignon aux stress oxydatif est partiellement dépendante du métabolisme du mannitol qui participe à la résistance des conidies lors du burst oxydatif in planta ou à la protection contre les dommages intracellulaires des FAO générées par les ITC lors des phases précoces de l'interaction. Les travaux réalisés montrent également que la charge fongitoxique des dérivés des glucosinolates peut être inhibée par leur conjugaison au glutathion via des Glutathion-Stransférases (GST) spécifiques. L'altération du métabolisme du mannitol ou l'inactivation de ces GST diminue significativement le pouvoir pathogène d'A. brassicicola et la régulation de ces voies métaboliques est donc à considérer dans l'optique de développer de nouvelles stratégies de protection des cultures.

Escherichia (E.) coli O157:H7 survival in dry cured (uncooked) meat products leading to human illness outbreaks is an international problem. Their manufacture does not involve a heat kill step to ensure the destruction of the organism, and the adverse conditions created during processing may not be sufficient to prevent E. coli O157:H7 survival. Deodorized yellow mustard powder has antimicrobial properties from glucosinolate (sinalbin) hydrolysis catalyzed by the endogenous enzyme myrosinase, generating antimicrobial isothiocyanate (PHBIT). Previous work has shown that its addition during dry sausage manufacture was capable of eliminating the pathogen. In this study, its use for the same purpose was investigated during dry cured Westphalian ham production. Hams were inoculated with a 7.5 log cfu•g-1 cocktail of E. coli O157:H7, surface applied with 4% or 6% (w/w) deodorized yellow mustard powder, and monitored for E. coli O157:H7 survival during 80d ham maturation. One trial included the inoculation of Staphylococcus (S.) carnosus, a meat starter culture with myrosinase-like activity, onto the hams (after salt equilibration) to accelerate formation of antimicrobial isothiocyanate from mustard glucosinolate and help control the pathogen. In both trials, E. coli O157:H7 was reduced 3 log cfu•g-1 by 21d on hams treated with mustard powder, whereas only a 1 log cfu•g-1 reduction was found in the inoculated control which was not treated with mustard. By 45d, hams treated with mustard powder showed a reduction of >5 log cfu•g-1 E. coli O157:H7, whereas it took 80d to for numbers in control hams to be similarly reduced. Since a 5 log kill of E. coli O157:H7 was achieved in control hams by the end of 80d, dry cured Westphalian ham manufacture would be considered capable of controlling the risk of E. coli O157:H7 survival by North American regulatory agencies. However, deodorized yellow mustard powder at 4%, and to a greater extent at 6%, eliminated the pathogen at a significantly faster rate than the control during ham processing. Addition of the S. carnosus starter culture in trial 2 may have contributed to the maintenance of this effect through isothiocyanate formation. It also helped restore numbers of staphylococci, which were found to be sensitive to deodorized mustard powder.

Escherichia (E.) coli O157:H7 survival in dry cured (uncooked) meat products leading to human illness outbreaks is an international problem. Their manufacture does not involve a heat kill step to ensure the destruction of the organism, and the adverse conditions created during processing may not be sufficient to prevent E. coli O157:H7 survival. Deodorized yellow mustard powder has antimicrobial properties from glucosinolate (sinalbin) hydrolysis catalyzed by the endogenous enzyme myrosinase, generating antimicrobial isothiocyanate (PHBIT). Previous work has shown that its addition during dry sausage manufacture was capable of eliminating the pathogen. In this study, its use for the same purpose was investigated during dry cured Westphalian ham production. Hams were inoculated with a 7.5 log cfu•g-1 cocktail of E. coli O157:H7, surface applied with 4% or 6% (w/w) deodorized yellow mustard powder, and monitored for E. coli O157:H7 survival during 80d ham maturation. One trial included the inoculation of Staphylococcus (S.) carnosus, a meat starter culture with myrosinase-like activity, onto the hams (after salt equilibration) to accelerate formation of antimicrobial isothiocyanate from mustard glucosinolate and help control the pathogen. In both trials, E. coli O157:H7 was reduced 3 log cfu•g-1 by 21d on hams treated with mustard powder, whereas only a 1 log cfu•g-1 reduction was found in the inoculated control which was not treated with mustard. By 45d, hams treated with mustard powder showed a reduction of >5 log cfu•g-1 E. coli O157:H7, whereas it took 80d to for numbers in control hams to be similarly reduced. Since a 5 log kill of E. coli O157:H7 was achieved in control hams by the end of 80d, dry cured Westphalian ham manufacture would be considered capable of controlling the risk of E. coli O157:H7 survival by North American regulatory agencies. However, deodorized yellow mustard powder at 4%, and to a greater extent at 6%, eliminated the pathogen at a significantly faster rate than the control during ham processing. Addition of the S. carnosus starter culture in trial 2 may have contributed to the maintenance of this effect through isothiocyanate formation. It also helped restore numbers of staphylococci, which were found to be sensitive to deodorized mustard powder.

Made available in DSpace on 2015-03-26T13:30:35Z (GMT). No. of bitstreams: 1 texto completo.pdf: 217734 bytes, checksum: 6fd7a4c6b5089dddf92260f4cc930663 (MD5) Previous issue date: 2011-03-16 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The aim of this study was to evaluate the toxicity of the essential oil of mustard (EOM) for adults of five populations of Sitophilus zeamais (Coleoptera: Curculionidae) and the influence of the essential oil on the locomotory behavior of the populations. EOM was used with 90% of allyl isothiocyanate volatile component (ITCA), diluted in soybean oil at 1:9 v/v to obtain a 9% solution of ITCA. EOM was applied on filter paper placed in Petri dishes (5.0 cm diameter). The dishes were covered with organza and placed inside glass jars of 0.8 L, and 50 adult insects were transferred to the jars, which were kept closed for 48 hours. EOM was used at concentrations ranging from 1.2 to 2.8 &#956;L L-1. The S. zeamais populations used were from Abre Campo, Machado, Paracatu, Piracicaba and Tunápolis. The toxicity of EOM was evaluated by determining the lethal concentrations (CL) to 50 (LC50) and 95% (LC95) of adult insects, which were then used to estimate the toxicity ratio. The following locomotory behavioral parameters were studied: walked distance, walking velocity, resting time, and number of stops, as well as the number of takeoffs and flying height of the insects. Additionally, the instantaneous rates of increase (ri), the respiration rate (CO2 production) and body mass were evaluated for all populations. The most susceptible population to EOM was Piracicaba for wich the lowest LC50 was obtained (1.49&#956;L L-1). This concentration was used for all the other assays treated with EOM, except the instantaneous rate of population growth, which hand no EOM treatment. The Paracatu population showed the highest LC50 (2.97 &#956;L L-1) and LC95 (6.82 &#956;L L-1) while Machado showed the lowest LC95 (2.16 &#956;L L-1). The toxicity ratio based on the LC50 ranged from 1.08 to 1.99 times, and from 0.76 and 2.42 times based on the LC95. The slopes of the concentration mortality curves varied among the populations from 4.56 ± 0.72 (Paracatu) to 13.14 ± 0.75 (Tunápolis). The distance walked did not significantly differ between insects treatead with EOM and control or among populations. However, regarless of the population, the resting time of the insects was reduced by treatment with EOM. The other walking parameters (walking velocity and number of stops), flight parameters (flying height and number of takeoffs), respiratory rate, and body mass, the only varied among the populations, but no difference existed for insects exposed or not exposed to EOM. In conclusion, the EOM was toxic to the five populations of S. zeamais and did not promote major changes in the locomotory behavior of the insects. Different locomotory behavioral patterns, respiratory rate, and body mass were observed in the S. zeamais populations, but with uniform response to mustard oil; these differences should be inherent to the genetic make up of the populations. / O objetivo deste trabalho foi avaliar a toxicidade do óleo essencial de mostarda (OEM) para adultos de cinco populações de Sitophilus zeamais (Coleoptera: Curculionidae) e verificar a influência do óleo essencial sobre o comportamento locomotor dos insetos. Foi utilizado OEM com 90% do componente volátil Isotiocianato alilo (ITCA), diluído em óleo de soja, na proporção de 1:9 v/v, para obter solução oleosa de 9% de ITCA. O OEM foi aplicado em papel-filtro colocado em placas de Petri (5,0 cm diâmetro), que foram cobertas com organza e colocadas no interior de frascos de vidro de 0,8 L, aos quais foram acrescentados posteriormente 50 insetos adultos. Os frascos foram mantidos fechados por 48h. Utilizou-se o OEM em concentrações variando de 1,2 a 2,8 &#956;L L-1. As populações de S. zeamais utilizadas foram Abre Campo, Machado, Paracatu, Piracicaba e Tunápolis. Avaliou-se a toxicidade do OEM por meio da estimativa das concentrações letais (CL) para 50 (CL50) e 95% (CL95) dos insetos adultos. As CL50 e CL95 foram usadas para calcular as respectivas razões de toxicidade. Foram avaliadas também as características comportamentais de caminhamento: distância percorrida, velocidade de caminhamento, tempo de repouso e número de paradas, bem como as características de voo como número de decolagens e altura de voo dos insetos. Adicionalmente, foram avaliadas as taxas instantâneas de crescimento populacional (ri), as taxas respiratórias (produção de CO2) e massa corpórea para todas as populações. A população padrão de susceptibilidade foi a da cidade de Piracicaba, pois apresentou menor CL50 (1,49 &#956;L L- 1). Esta concentração foi utilizada para todos os bioensaios tratados com o OEM, exceto para a taxa instantânea de crescimento populacional, em que não se utilizou o tramento com OEM. A população de Paracatu foi a que apresentou maior CL50 (2,97 &#956;L L-1) e CL95 (6,82 &#956;L L-1), enquanto Machado foi a população que apresentou menor CL95 (2,16 &#956;L L-1). A razão de toxicidade com base na CL50 variou entre 1,08 e 1,99 vezes, e entre 0,76 e 2,42 vezes baseada na CL95. As inclinações das curvas de concentração-mortalidade variaram entre as populações, sendo menor (4,56 ± 0,72) para a população de Paracatu e maior (13,14 ± 0,75) para a de Tunápolis. Não houve diferença significativa na distância percorrida entre os tratamentos com OEM e controle, nem entre as populações. No entanto, o tempo de repouso dos insetos foi reduzido pelo tratamento com OEM em todas as populações. Para os outros padrões comportamentais de caminhamento (velocidade de caminhamento e número de paradas), de voo (altura de voo e número de decolagens), taxa respiratória e de massa corpórea, houve diferença apenas entre as populações, não diferindo quando na presença ou ausência do OEM. Com isso, conclui-se que o OEM foi tóxico para as cinco populações de S. zeamais e que este óleo não promoveu grandes alterações no comportamento locomotor dos insetos. Diferentes padrões comportamentais, respiratórios e de massa corpórea foram observados nas populações de S. zeamais, porém com uniformidade de resposta ao óleo de mostarda, sendo que estas diferenças devem ser inerentes à constituição genética das populações.

京都大学 / 0048 / 新制・課程博士 / 博士(農学) / 甲第22486号 / 農博第2390号 / 新制||農||1075(附属図書館) / 学位論文||R2||N5266(農学部図書室) / 京都大学大学院農学研究科森林科学専攻 / (主査)教授 髙野 俊幸, 教授 和田 昌久, 教授 河本 晴雄 / 学位規則第4条第1項該当 / Doctor of Agricultural Science / Kyoto University / DGAM

No description available.

This study examined the feasibility of using (BETA)-cyclodextrins ((BETA)CDs), which are derived from starch, as agents to stabilize volatile and leachable biocides for the protection of wood and wood composites. The encapsulation of volatile natural antimicrobial compounds, such as allyl isothiocyanate (AITC) and essential oils (EOs), in βCDs was qualitatively confirmed by Attenuated total reflection Fourier-transform infrared spectroscopy (ATR-FTIR) method and the maximum inclusion yield was quantitatively estimated by ultraviolet-visible spectrophotometry (UV/VIS) while the partial fixation of leachable borates with βCD was confirmed by ATR-FTIR and nuclear magnetic resonance (NMR) techniques. The efficacy of the βCD complexes as wood preservatives of southern yellow pine and randomly Oriented Strand Board (OSB) was examined in soil block tests (AWPA E10-16 and E22-16 standard). The results indicate that (A) (BETA)CDs suppress the premature leaching of otherwise volatile natural compounds and suggest a novel approach to the application of volatile or water-immiscible natural preservatives for wood and wood composites protection; (B) (BETA)CD can be used as an agent for partial fixation of boric acid to form boric acid esters. However, the borate esters are susceptible to leach out after AWPA E11 test and not suitable for protection against Gloeophyllum trabeum and Postia placenta in outdoor conditions.