Since their accidental introduction into the Great Lakes in mid- to late-1980s, the freshwater zebra mussels, Dreissena polymorpha, have colonized most lakes and waterways across eastern North America. Their rapid spread is partly attributed to their ability to tenaciously attach to hard substrates via an adhesive apparatus called the byssus, resulting in serious environmental and economic impacts. A detailed ultrastructural study of the bysuss revealed a 10 nm adhesive layer at the attachment interface. Distributions of the main adhesive amino acid, 3,4-dihydroxyphenylalanine (DOPA), and its oxidizing (cross-linking) enzyme, catechol oxidase, were determined histochemically. It was found that, upon aging, DOPA levels remained high in the portion of the byssus closest to the interface, consistent with an adhesive role. In contrast, reduced levels of DOPA corresponded well with high levels of catechol oxidase in the load-bearing component of the byssus, presumably forming cross-links and increasing the cohesive strength.

Since their accidental introduction into the Great Lakes in mid- to late-1980s, the freshwater zebra mussels, Dreissena polymorpha, have colonized most lakes and waterways across eastern North America. Their rapid spread is partly attributed to their ability to tenaciously attach to hard substrates via an adhesive apparatus called the byssus, resulting in serious environmental and economic impacts. A detailed ultrastructural study of the bysuss revealed a 10 nm adhesive layer at the attachment interface. Distributions of the main adhesive amino acid, 3,4-dihydroxyphenylalanine (DOPA), and its oxidizing (cross-linking) enzyme, catechol oxidase, were determined histochemically. It was found that, upon aging, DOPA levels remained high in the portion of the byssus closest to the interface, consistent with an adhesive role. In contrast, reduced levels of DOPA corresponded well with high levels of catechol oxidase in the load-bearing component of the byssus, presumably forming cross-links and increasing the cohesive strength.

Made available in DSpace on 2016-08-19T12:56:42Z (GMT). No. of bitstreams: 1 dissertacao Mariane.pdf: 1393014 bytes, checksum: 91191392c6eda20c7e1264cf9608ef7a (MD5) Previous issue date: 2013-11-29 / Essential oils (OEs) are natural plant extracts and many of them are active as antimicrobials. Origanum vulgare L. (oregano) essential oil (OEO) has a promising application field as a food preservative. Several in vitro and application studies has been carried to evaluate the activity of OEs as antimicrobials in foods, but are not found in the literature survey data application in mussels. In this study we evaluated the chemical composition and the antibacterial effect of OEO in fresh chilled mussels from Mytella falcata species. The chemical constituents of the studied OE were identified by gas chromatography-mass spectrometry and for activity we analyzed the count of Escherichia coli and aerobic mesophilic bacteria, total volatile bases and pH. The addition of OEO at 1.4% resulted in complete inhibition of E. coli inoculated, reduced growth aerobic plate count bacteria and inhibit the process of deterioration. The activity of the OEO is attributed mainly to its major component, carvacrol, which has recognized antibacterial activity. The results indicate that the OEO can be applied to support of the extension of shelf life and safety of fresh mussels. / Óleos essenciais (OEs) são extratos naturais de plantas, sendo muitos deles ativos como antimicrobianos. O óleo essencial de Origanum vulgare L. (orégano) (OEO) possui um promissor campo de aplicação como conservante de alimentos. Diversos estudos in vitro e de aplicação têm sido feitos para avaliar a atividade de OEs como antimicrobianos em alimentos, no entanto não são encontrados na literatura dados de pesquisas de aplicação em mariscos. Neste estudo avaliamos a composição química do OEO e seu efeito antibacteriano em mariscos in natura refrigerados da espécie Mytella falcata, conhecidos como sururu. Os constituintes químicos do OE estudado foram identificados por cromatografia gasosa acoplada à espectrometria de massas e para a atividade realizamos as análises de contagem de Escherichia coli e bactérias mesófilas totais, teor de bases voláteis totais e pH do sururu. A adição de OEO a 1,4% resultou na completa inibição da E. coli inoculada, diminuição do crescimento de bactérias mesófilas totais e tornou o processo de deterioração mais lento. A atividade do OEO é atribuída principalmente ao seu componente majoritário, o carvacrol, que possui atividade antibacteriana. Os resultados obtidos indicam que o OEO pode ser aplicado no auxilio da extensão do prazo de validade e segurança de sururus in natura.

Kyoto University (京都大学) / 0048 / 新制・課程博士 / 博士(工学) / 甲第15315号 / 工博第3194号 / 新制||工||1481(附属図書館) / 27793 / 京都大学大学院工学研究科都市環境工学専攻 / (主査)教授 角 哲也, 准教授 竹門 康弘, 准教授 武藤 裕則 / 学位規則第4条第1項該当

Os mexilhões cultivados no litoral Norte de São Paulo, município de Ubatuba, são comercializados in natura, constituindo risco à população. Com o crescimento da atividade é possível sugerir a implantação de uma unidade de processamento de mexilhões que promova um aumento do tempo de armazenamento, facilitando a comercialização e permitindo a exportação, além de fornecer ao consumidor um produto de melhor qualidade. Os mexilhões foram submetidos ao processamento por cocção, congelamento e armazenamento, sendo então determinados o ponto de congelamento, a velocidade de congelamento a as curvas de congelamento do mexilhão semidesconchado. A qualidade microbiológica e físico-química do produto foi avaliada. O beneficiamento do mexilhão iniciou-se com a cocção por imersão em água à ebulição por 10 minutos. Após a retirada das conchas, os mexilhões foram congelados individualmente IQF (Individually Quick Frozen) a –20ºC e armazenados a -18ºC durante 90 dias. A curva de congelamento do mexilhão apresentou forma geral típica, com o ponto de congelamento situando-se na faixa de zero a –1,5ºC; a velocidade de congelamento variou de 2 cm/h a 3,3 cm/h, conforme a disposição dentro da câmara de congelamento. Os resultados físico-químicos mostraram que não houve diferença significativa no valor nutricional dos mexilhões in natura, processados e armazenados, apresentando os teores médios de 7,4mg/100g de proteínas, 5,8 mg/100g de carboidratos e 1,4 mg/100g de lipídeos. Os valores encontrados para BNVT, TMA e pH no mexilhão in natura foram, 4,3 mg/100g; 2,0 mg/100g e 6,2, respectivamente, estando dentro dos limites estipulados pela legislação de 30mg/100g para BNVT e 4 mg/100g de TMA. Após o processo de cocção e congelamento houve um aumento no valor do pH para 6,9, enquanto o BNVT manteve-se na média. Todas as amostras de mexilhão in natura atenderam aos padrões microbiológicos estabelecidos pela legislação (RDC, nº12 de 02 de janeiro de 2001). Salmonella sp e Vibrio parahaemolyticus não foram isoladas em nenhuma das amostras de mexilhões in natura, cozidos, congelados e armazenados. O tratamento térmico foi efetivo no controle dos coliformes fecais, redução de coliformes totais, Staphylococcus coagulase+ e psicrotróficos. O processo de congelamento reduziu a contagem de coliformes totais e Staphyloocccus coagulase+, mantendo-se inalterados durante o armazenamento a –18ºC por 90 dias. Concluiu-se que o beneficiamento do mexilhão pelo processo combinado de cocção, congelamento e armazenamento assegura a qualidade físico-química e microbiológica do produto, podendo ser adotado como padrão para industrialização. / The mussels cultivated in the coast North of São Paulo, city of Ubatuba, are commercialized in natura, constituting risk to the population. With the growth of the activity it is possible to suggest the implantation of a unit of mussel processing that promotes an increase of the storage time, facilitating the commercialization and allowing the exportation, besides supplying to the consumer a product of better quality. The mussels had been submitted to the processing for cooking, freezing and storage, being then determined the freezing point, the speed of freezing to the curves of freezing of the semidesconchado mussel. The microbiological quality and physicochemical of the product were evaluated. The processing of the mussel was started with the immersion in boiling water per 10 minutes. After the withdrawal of the shells, the mussels had been frozen individually IQF (Individually Quick Frozen) at -20ºC and stored at -18ºC during 90 days. The curve of freezing of the mussel presented typical general form, with the freezing point placing from zero to -1,5ºC; the freezing speed varied from 2 cm.h-1 to 3,3 cm.h-1, as the disposal

<p>The development of new materials has been inspired by lessons learned from natural systems. In the area of underwater adhesion and adhesives, inspiration has come from the complex protein adhesives generated by marine organism such as barnacle and mussels. These protein systems have a high incorporation of a unique amino acid, dihydroxyphenylalanine, and provides the unique adhesive qualities synthetic systems strive to emulate.</p> <p>By understanding how marine mussels stick to a variety of surfaces, new strategies can be explored for preventing the adhesion of biological organisms to various substrates. A continuous concern for marine vessels is the detrimental impact caused by biofouling on the hull of the ship. Fuel consumption can increase as the vessel’s drag increasing fuel consumption and non-native species can be introduced into new environments. Taking inspiration from catechol curing, new oxidative surfaces were investigated as potential antifouling coatings.</p> <p>Further insight into the marine mussels ability to apply and cure its adhesive on a variety of substrate has also inspired various synthetic polymers. The catechol moiety can be incorporated into a polymer backbone to give a new solvent based adhesive. Further investigation of the poly(styrene-co-(3,4-dihydroxystyrene)) adhesive system was done to formulate an underwater adhesive for unique use cases. A terpolymer was also explored as an ideal adhesive taking inspiration from the mussels by incorporating flexible, stiff, and sticky components to give a tunable adhesive.</p> <p>Having a strong bonding synthetic adhesive that can be used on a laboratory scale is good for academic investigation, but not of use outside the lab if it cannot easily be produced on a commercial scale. With the goal of large scale synthesis, a new polymerization method was introduced addressing some of the issues currently preventing commercial scale production.</p><br>

L’accroissement de la population humaine mondiale a des répercussions majeures, ce n’est donc pas surprenant, compte tenu de la nécessité de nourrir une population grandissante au niveau planétaire, que la production en conchyliculture ait augmenté au cours des dernières décennies. Or, les connaissances acquises concernant les divers facteurs du déterminisme du sexe et du rapport des sexes chez les bivalves sont très limitées et cela pourrait ralentir grandement le taux de production des éleveurs et leur capacité à intervenir si les stocks venaient à diminuer de façon inquiétante. Certains travaux mentionnent que certains facteurs environnementaux, comme la température, auraient un effet sur le rapport des sexes chez une variété de bivalves, incluant la moule bleue commerciale Mytilus edulis, quoiqu’aucune étude n’ait validé cette dernière possibilité. Cela dit, il est possible que l’environnement des adultes puisse aussi affecter le phénotype de la progéniture. En effet, une transmission intergénérationnelle a déjà été identifiée chez Mytilus, mais la possibilité que les conditions des parents affectent le rapport des sexes spécifiquement n’a jamais été abordée. Il est toutefois connu qu’un facteur maternel présent dans l’œuf affecte le sexe de la progéniture et que cette espèce de bivalve a un mode de transmission des mitochondries particulier. Ce mode de transmission appelé « transmission doublement uniparentale » a rendu possible l’identification du sexe chez les embryons. De cette façon, 1938 embryons provenant de 25 croisements artificiels réalisés à trois températures et effectués lors de trois différentes années ont été analysés. Nos analyses mettent en évidence une variation significative dans la proportion de larves femelles entre les années passant de 64 % à 98 %. Dans certains cas, la proportion de femelle varie de 0 à 100 % entre les différents traitements. Même si un effet général sur le rapport des sexes n’était pas significatif, chaque croisement s’est avéré avoir une norme de réaction qui lui est propre face aux 3 différentes températures. Cette étude met en valeur l’effet important de l’environnement sur le déterminisme du sexe chez M. edulis, autant chez les parents que lors du développement des embryons. / The factors affecting sex determination still remain unknown for most bivalve species. Some studies reported that environmental factors, such as temperature, influence sex determination in certain species, and this has been hypothesized also for the blue mussel Mytilus edulis, but not experimentally validated yet. Adult exposure to different environmental conditions during gametogenesis, which occurs seasonally, may also affect offspring phenotype, including sex determination. Intergenerational carryover effects have been reported in bivalves, but the impact of parental exposures on offspring sex determination has not been examined so far. To address these questions, artificial fertilizations were performed on individuals collected in three different years and their embryos and larvae were reared at three different temperatures to specifically test if the environment influence offspring sex ratio through effects on parental developing gametes and/or on developing embryos. We took advantage of the doubly uniparental inheritance of mitochondria in bivalves to determine the sex of the larvae. The analysis of 1938 larvae from 25 crosses revealed that the overall proportion of female larvae was significantly different among years, varying from 64 % to 98 %. While the proportion of female larvae across temperature ranged from 0 to 100 % in some cases, the reaction norms were cross-specific and there were no significant effects of rearing temperature on sex ratio. Taken together, our results suggested that sex determination in M. edulis occur during the gametogenesis according to the genotype of the parents, but could also be changed during the development. More importantly, both processes are strongly affected by environmental conditions.

Kinlock is a freshwater mussel shell ring site located in Sunflower County in the Mississippi Delta. Little work has been done at freshwater mussel shell rings, and therefore little is known about them. This thesis uses four different data collection methods to answer questions of chronology, site layout, etc. These four methods are controlled surface collection, excavation, coring, and magnetometry. Based on the results of these methods, Kinlock was found to be a Woodland period mussel shell ring with a later Mississippian period component built on top of the shell. This later component consisted of five mounds situated around a plaza. It was also found that the plaza was planned and maintained from the Woodland period through the Mississippian period, until the site was abandoned.

Verschiedene marine Lebewesen, wie zum Beispiel Muscheln, zeigen beeindruckende Unterwasserklebefähigkeiten. Vor allem L-3,4-Dihydroxyphenylalanin (Dopa), ein sehr häufig vorkommendes Aminosäurederivat in den Proteinen des Muschelklebesystems, wirkt sich positiv auf die Adhäsions- und Kohäsionsfähigkeit der Muschel aus. Im Rahmen dieser Arbeit dient die Bildung von Cysteinyldopa, welches als biogene Verknüpfung in Proteinen vorkommt, als Inspiration für die Entwicklung eines chemischen Ansatzes zur Synthese muschelmimetischer Klebstoffe. In einem AA+BB-Polyadditionsansatz (muschelinspirierte Polymerisation, MIPoly) werden Dichinone und Dithiole als Monomere eingesetzt. Hierfür werden die Dichinone ausgehend von der chemisch vielfältigen Familie der Bisphenol-Monomere durch Oxidation mit 2-Iodoxybenzoesäure synthetisiert. Die Dichinone und die Dithiole reagieren bei Raumtemperatur in einer Michael-artigen Polyaddition, wodurch Polymeren erhalten werden, die adhäsive Thiol-Catechol-Verknüpfungen (thiol-catechol-connectivities, TCCs) in ihrem Rückgrat aufweisen. Die detaillierte Untersuchung des MIPoly-Prozesses, der gebildeten TCC-Polymere sowie niedermolekularer Modellreaktionen ermöglicht den Nachweis der TCC-Bildung und bestätigte den Michael-artigen-Polyadditionsmechanismus. Dieses chemische MIPoly ist eine robuste Reaktion, die eine einfache Skalierbarkeit verspricht und einen modularen Ansatz für maßgeschneiderte Klebstoffe bietet. Der generische Charakter der untersuchten MIPoly wird durch die Synthese einer TCC-Polymermatrix nachgewiesen. In Klebetests zeigen die synthetisierten TCC-Polymere Hafteigenschaften auf Aluminium und Polypropylen. Darüber hinaus können ausgewählte TCC-Polymere als Unterwasserklebstoffe unter Meerwassermodellbedingungen verwendet werden. / Different marine organisms, such as mussels, provide impressive under water gluing capabilities. Mainly L-3,4-dihydroxyphenylalanin (Dopa), which is a highly abundant amino acid derivative in the proteins of the mussel gluing system, was found to have a positive effect on the adhesion and cohesion ability of the mussel. Here, the formation of cysteinyldopa as biogenic connectivity in proteins is used to inspire a chemical pathway toward mussel-adhesive mimics. In an AA+BB polyaddition approach (Mussel-inspired polymerization, MIPoly) bisquinones and dithiols are used as monomers. The bisquinones are synthesized from the chemically diverse family of bisphenol monomers by oxidation with 2-iodoxybenzoic acid. The bisquinones and the dithiols react at room temperature in Michel-type polyaddition, leading to polymers with adhesive thiol-catechol-connectivities (TCCs) in their backbone. The detailed investigation of the MIPoly process, the formed TCC-polymers as well as low molecular model reactions enable the verification of the TCC-formation and confirm the Michael-type polyaddition mechanism. This chemical MIPoly is a robust reaction that promises ease of scale up and provides a modular approach to tailor adhesives. The generic character of the investigated MIPoly process is shown by synthesizing a TCC-polymer matrix. In adhesive tests, the synthesized TCC-polymers show adhesive properties on aluminum and poly(propylene). Furthermore, selected TCC-polymers can be used as underwater adhesives in seawater modeling aqueous environments.

L’épigénétique se rapporte à un ensemble de mécanismes qui modifient l'expression des gènes sans modifier la séquence nucléotidique sous-jacente, produisant une large gamme de variations phénotypiques et répondant aux fluctuations de l'environnement externe ou interne. La méthylation de l'ADN est le processus épigénétique le plus étudié dans les génomes nucléaires des mammifères. Il existe toutefois des lacunes significatives dans la littérature concernant la méthylation de l'ADN mitochondrial (ADNmt), surtout chez les invertébrés. Les bivalves constituent un modèle particulièrement intéressant pour étudier l’épigénétique mitochondriale ou « mitoépigénétique » puisqu’ils possèdent un système de transmission uniparentale double (DUI) de leur mitochondrie, par lequel les mâles héritent des ADNmt paternel (ou mâle ; M) et maternel (ou femelle ; F). La présente étude avait pour objectif de confirmer l’existence de méthylation dans l’ADNmt de la moule bleue (Mytilus edulis), une espèce à DUI. Notre étude a permis de localiser, par immunofluorescence, des cytosines (5mC) et des adénines (6mA) méthylées, ainsi que des méthyltransférases spécifiques aux adénines et aux cytosines, au sein des mitochondries de cette espèce. Ces résultats sont appuyés par une détection de 5mC et de 6mA dans l’ADNmt par digestions enzymatiques, et confirment la présence de méthylation de l'ADNmt chez M. edulis. Nos résultats en immunofluorescence ont également dévoilé un lien entre la présence de 5mC et le stade de développement des gamètes mâles, c’est-à-dire que les gamètes immatures (spermatides) étaient tous méthylés (au niveau mitochondrial) alors qu’une faible proportion de gamètes matures (spermatozoïdes) présentait ce statut de méthylation. Ceci vient corroborer nos résultats enzymatiques, lesquels ont démontré une plus grande variabilité de méthylation entre les mâles qu’entre les femelles. Enfin, nous avons détecté, par séquençage du méthylome de l’ADNmt, un pic de 5mC en contexte non-CpG conservé entre les ADNmt M et F chez les mâles au sein de la région de contrôle de la réplication, soutenant les résultats d’études antérieures chez les vertébrés. Notre étude est la première à démontrer la présence de méthylation dans l’ADNmt d’une espèce DUI, et met en lumière le rôle potentiel de la méthylation de l'ADN dans leur système de transmission mitochondriale. / Epigenetics refers to a set of mechanisms that modify gene expression without altering the underlying nucleotide sequence, producing a wide range of phenotypic variations, and responding to the external or internal environmental fluctuations. DNA methylation is the most extensively studied epigenetic process in mammalian nuclear genomes. However, there are significant gaps in the literature concerning mitochondrial DNA (mtDNA) methylation, especially in invertebrates. Bivalves are a particularly interesting model for studying mitochondrial epigenetics or “mitoepigenetics”, as they possess a doubly uniparental inheritance (DUI) system of their mitochondria, whereby males inherit both paternal and maternal mtDNAs. The aim of this study was to confirm the existence of methylation in the mtDNA of the blue mussel (Mytilus edulis), a DUI species. Using immunofluorescence, we localized methylated cytosines (5mC) and adenines (6mA), as well as adenine- and cytosine-specific methyltransferases, in mitochondria of this species. These results are supported by the detection of 5mC and 6mA in mtDNA by enzymatic digestions, and confirm the presence of mtDNA methylation in M. edulis. Our immunofluorescence results also revealed a link between the presence of 5mC and the developmental stage of male gametes, i.e. immature gametes (spermatids) were all methylated in their mitochondria while only a small proportion of mature gametes (spermatozoa) showed this methylation status. This corroborates our enzymatic results, which demonstrated greater variability in cytosine methylation status among males than among females. Finally, we detected, by mtDNA methylome sequencing, a 5mC peak in non-CpG context conserved between the paternal and maternal mtDNA in males in the region responsible for control of replication (control region), supporting the results obtained in previous studies on vertebrate. Our study is the first to demonstrate the presence of mtDNA methylation in a DUI species, and highlights the potential role of DNA methylation in their mitochondrial transmission system.