xxii, 242 p. : ill. (some col.) / The arminacean nudibranch Janolus fuscus (family Zephyrinidae) is found in rocky intertidal habitats along the northeast Pacific coast. Adult J. fuscus are conspicuous from April to October but absent in the early winter at two sites, North Cove and Fossil Pt., in the Coos Bay region of Oregon. Over four years of intertidal surveys at these sites, the density of J. fuscus peaked with the abundance of their bryozoan prey, Bugula pacifica and Tricellaria circumternata , in spring and summer, while adult absence in winter was correlated with strong winter storms. To describe the timing of development and determine the life cycle of J. fuscus , embryos and larvae were reared in the laboratory and examined with light, scanning electron, and confocal microscopy. Larvae reared in the lab and juveniles collected from the field were monitored to quantify growth. Janolus fuscus exhibited typical spiral cleavage and hatched as planktotrophic veligers that grew for over a month before they reached competency, settled, and metamorphosed on their prey, B. pacifica . Juvenile growth was rapid, and adults reached maximum sizes of over 50 mm before dying. These demographic and developmental studies suggest that J. fuscus is a subannual species with a life span of approximately five months. Janolus fuscus is often infected with an endoparasitic copepod, Ismaila belciki . In the field, prevalence of I. belciki increased with host density and size. The distribution of I. belciki was weakly aggregated in the host population. The large female parasite was generally found in the anterior portion of the host hemocoel, and one or more dwarf males were typically associated with each female. Infected J. fuscus produced significantly smaller egg masses with fewer larvae than did uninfected individuals. Infection did not influence growth rate but did cause decreased survival in older nudibranchs. To examine the life cycle of I. belciki , naupliar larvae were reared in the lab and incubated with potential hosts. Additionally, copepodid stages were described from dissected J. fuscus collected from the field. Ismaila belciki has a least three planktotrophic naupliar stages and four copepodid stages in its life cycle. / Committee in charge: Barbara Roy, Chairperson; Craig Young, Advisor; Richard Emlet, Member; Sandra Brooke, Member; Frances White, Outside Member

A presente investigação teve por objetivo o isolamento de metabólitos secundários biologicamente ativos de nudibrânquios, moluscos conhecidos por produzirem ou acumularem substâncias a partir de suas presas. Foram investigados extratos de quatro espécies de nudibrânquios marinhos juntamente com suas respectivas presas. Além disso, também foi investigado o extrato ativo da esponja marinha Agelas sventres. O estudo realizado com o extrato bruto da esponja marinha Agelas sventres levou ao isolamento de uma série de alcalóides bromopirrólicos, compostos tipicamente encontrados em esponjas do gênero Agelas. Dentre os compostos isolados, a oroidina apresentou atividade inibitória frente à enzima Pdr5p de Saccharomyces cerevisiae. O estudo do nudibrânquio Tambja stegosauriformis e de sua presa, o briozoário Bugula sp., levou ao isolamento de diversos alcalóides da classe das tambjaminas. As tambjaminas C, D, K e o produto de hidrólise da tambjamina B foram observados nos dois animais; o produto de hidrólise da tambjamina A foi encontrado apenas no extrato do nudibrânquio, enquanto que a tambjamina A e um isômero da tambjamina J foram encontrados apenas no extrato do briozoário. O estudo do nudibrânquio Okenia zoobotryon e de sua presa, o briozoário Zoobotryon verticillatum, resultou no isolamento de um único alcalóide indólico conhecido, 2,5,6-tribromo-Nmetilgramina, presente nos dois animais. Resultados semelhantes foram obtidos a partir da investigação do extrato do nudibrânquio Hypselodoris lajensis e de sua presa, uma esponja do gênero Dysidea, com o isolamento de um único diterpeno, a lactona da furodisinina. Embora ambas substâncias sejam conhecidas, este foi o primeiro isolamento destes compostos a partir de espécies de nudibrânquios. Finalmente, a partir do extrato do nudibrânquio Pleurobranchus areolatus foram isoladas duas novas dicetopiperazinas modificadas, estruturalmente semelhantes às rodriguesinas A e B, outras dicetopiperazinas isoladas a partir da ascídia Didemnum sp., provável presa desta espécie de nudibrânquio. Vale ressaltar a utilização de análises por LC-UV-MS e MS/MS neste trabalho, que auxiliaram na identificação uma série de compostos presentes nos extratos estudados no presente trabalho, mesmo em quantidades muito pequenas. / Abstract The present investigation aimed the isolation of biologically active secondary metabolites from different species of nudibranchs, mollusks that can produce or accumulate substances from their preys. We investigated the extracts of four nudibranchs species and their respective preys. The active extract of the marine sponge Agelas sventres, has also been investigated. From the extract of the marine sponge Agelas sventres we could isolate a series of bromopyrrolic alkaloids, substances that are typically found in sponges of Agelas genus. Among the isolated compounds, oroidin was found to inhibit the activity and function of the Pdr5p enzyme from Saccharomyces cerevisiae. From the extract of the nudibranch Tambja stegosauriformis and its prey, the bryozoan Bugula sp., several known tambjamines alkaloids were isolated. The tambjamines C, D, K, and the aldehyde of the tambjamine B were found in both animals; aldehyde of tambjamine A was identified only in the nudibranch extract, whereas tambjamine A and an isomer of tambjamine J were found on the bryozoan. The study of the extract of the nudibranch Okenia zoobotryon and its prey, the bryozoan Zoobotryon verticillatum, resulted in the isolation of a single known brominated indole alkaloid, 2,5,6-tribromo-N-metilgramine, present on both animals. Similar results were obtained in the study of extract of the nudibranch Hypselodoris lajensis along with its prey, a Dysidea sponge, that led to the isolation of a single diterpene, the furodysinin lactone. Although both compounds are known, this is the first report on the isolation of those compounds from nudibranch species. Finally, the investigation of the extract from the nudibranch Pleurobranchus areolatus provided two new modified diketopiperazines, closely related to modified diketopiperazines, the rodriguesins A and B, isolated from the ascidian Didemnum sp. It is important to note the use of LC-UV-MS and MS/MS analysis in this work, which were important in the identification of several compounds present in the studied extracts in very small amounts.

A presente investigação teve por objetivo o isolamento de metabólitos secundários biologicamente ativos de nudibrânquios, moluscos conhecidos por produzirem ou acumularem substâncias a partir de suas presas. Foram investigados extratos de quatro espécies de nudibrânquios marinhos juntamente com suas respectivas presas. Além disso, também foi investigado o extrato ativo da esponja marinha Agelas sventres. O estudo realizado com o extrato bruto da esponja marinha Agelas sventres levou ao isolamento de uma série de alcalóides bromopirrólicos, compostos tipicamente encontrados em esponjas do gênero Agelas. Dentre os compostos isolados, a oroidina apresentou atividade inibitória frente à enzima Pdr5p de Saccharomyces cerevisiae. O estudo do nudibrânquio Tambja stegosauriformis e de sua presa, o briozoário Bugula sp., levou ao isolamento de diversos alcalóides da classe das tambjaminas. As tambjaminas C, D, K e o produto de hidrólise da tambjamina B foram observados nos dois animais; o produto de hidrólise da tambjamina A foi encontrado apenas no extrato do nudibrânquio, enquanto que a tambjamina A e um isômero da tambjamina J foram encontrados apenas no extrato do briozoário. O estudo do nudibrânquio Okenia zoobotryon e de sua presa, o briozoário Zoobotryon verticillatum, resultou no isolamento de um único alcalóide indólico conhecido, 2,5,6-tribromo-Nmetilgramina, presente nos dois animais. Resultados semelhantes foram obtidos a partir da investigação do extrato do nudibrânquio Hypselodoris lajensis e de sua presa, uma esponja do gênero Dysidea, com o isolamento de um único diterpeno, a lactona da furodisinina. Embora ambas substâncias sejam conhecidas, este foi o primeiro isolamento destes compostos a partir de espécies de nudibrânquios. Finalmente, a partir do extrato do nudibrânquio Pleurobranchus areolatus foram isoladas duas novas dicetopiperazinas modificadas, estruturalmente semelhantes às rodriguesinas A e B, outras dicetopiperazinas isoladas a partir da ascídia Didemnum sp., provável presa desta espécie de nudibrânquio. Vale ressaltar a utilização de análises por LC-UV-MS e MS/MS neste trabalho, que auxiliaram na identificação uma série de compostos presentes nos extratos estudados no presente trabalho, mesmo em quantidades muito pequenas. / Abstract The present investigation aimed the isolation of biologically active secondary metabolites from different species of nudibranchs, mollusks that can produce or accumulate substances from their preys. We investigated the extracts of four nudibranchs species and their respective preys. The active extract of the marine sponge Agelas sventres, has also been investigated. From the extract of the marine sponge Agelas sventres we could isolate a series of bromopyrrolic alkaloids, substances that are typically found in sponges of Agelas genus. Among the isolated compounds, oroidin was found to inhibit the activity and function of the Pdr5p enzyme from Saccharomyces cerevisiae. From the extract of the nudibranch Tambja stegosauriformis and its prey, the bryozoan Bugula sp., several known tambjamines alkaloids were isolated. The tambjamines C, D, K, and the aldehyde of the tambjamine B were found in both animals; aldehyde of tambjamine A was identified only in the nudibranch extract, whereas tambjamine A and an isomer of tambjamine J were found on the bryozoan. The study of the extract of the nudibranch Okenia zoobotryon and its prey, the bryozoan Zoobotryon verticillatum, resulted in the isolation of a single known brominated indole alkaloid, 2,5,6-tribromo-N-metilgramine, present on both animals. Similar results were obtained in the study of extract of the nudibranch Hypselodoris lajensis along with its prey, a Dysidea sponge, that led to the isolation of a single diterpene, the furodysinin lactone. Although both compounds are known, this is the first report on the isolation of those compounds from nudibranch species. Finally, the investigation of the extract from the nudibranch Pleurobranchus areolatus provided two new modified diketopiperazines, closely related to modified diketopiperazines, the rodriguesins A and B, isolated from the ascidian Didemnum sp. It is important to note the use of LC-UV-MS and MS/MS analysis in this work, which were important in the identification of several compounds present in the studied extracts in very small amounts.

A total of 782 sea slug species (opisthobranch molluscs) within 161 genera, 56 families, and 7 orders are authentically recorded from Taiwan¡¦s Exclusive Economic Zone. Among these species, 459 species (58.7 %) are identified to species level and the other 323 species (41.3 %) are undescribed species. In terms of the whole Opisthobranchia fauna of the tropical western Pacific Ocean, approximately 1000 species are expected from Taiwan¡¦s EEZ. As most of the previous surveys on within-area species diversity were carried out in daytime, diel variation (i.e., day and night) in the species composition of sea slugs has been neglected. In order to assess whether such estimations for community diversity based only on daytime surveys are accurate, I undertook replicated diel surveys for 12 consecutive months (from December 2009 to November 2010) at Shilang Marine Reserve, Green Island (Lyudao), Taiwan. Phyllidiella pustulosa was observed most often during the daytime surveys, while Tritonia sp. 1 (an undescribed species) was the most abundant species at night. The results showed the species composition was clear different. During the field surveys, I found the difficult to identify the phyllidiid nudibranchs. Hence, I search for the additional taxonomic characters for phyllidiid nudibranchs base on integumentary spicules and gene sequences (COI and 16S genes). The results showed the spicules characters might provide the character to distinguish the Phyllidiella from other phyllidiid genera, but they were not informative at the species level. The results on molecular phylogeny showed that taxonomic status (both at the species and generic levels) of most phyllidiid genera, except Phyllidiella, received strong supports from COI gene and 16S gene. In contrast, each Phyllidiella species did not form a clade (suggesting the possibility of over estimating the species number in this genus). Finally, I described and illustrated three distinctive new species of Tambja (Nudibranchia: Polyceridae) from Taiwan and Australia. Among these three species, two of them were collected from Australia the other was collected from Taiwan. Tambja dracomus sp. nov. which is only distribution in cool temperate coastal waters in southeastern Australia and northern New Zealand; T. caeruleocirrus sp. nov. which is distributed in warm temperate coastal waters in eastern Australia, southeast Pacific Ocean. Tambja pulcherrima sp. nov. is widely distributed throughout the tropical, subtropical and warm temperate waters in western Pacific Ocean from Japan to northern New Zealand.