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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
71

Desenvolvimento inicial e comportamento alimentar da Matrinxã Brycon Amazonicus (GUNTHER, 1869), em laboratório

Sampaio, Ana Carolina Souza January 2010 (has links)
Dissertação(mestrado)-Universidade Federal do Rio Grande, Programa de Pós-Graduação em Aqüicultura, Instituto de Oceanografia, 2010. / Submitted by Cristiane Silva (cristiane_gomides@hotmail.com) on 2012-07-27T14:13:27Z No. of bitstreams: 1 dissertao corrigido final de ana carolina sampaio.pdf: 1962570 bytes, checksum: 530d0baf753727aa3bda4dcc7e937c68 (MD5) / Approved for entry into archive by Bruna Vieira(bruninha_vieira@ibest.com.br) on 2012-07-27T17:07:55Z (GMT) No. of bitstreams: 1 dissertao corrigido final de ana carolina sampaio.pdf: 1962570 bytes, checksum: 530d0baf753727aa3bda4dcc7e937c68 (MD5) / Made available in DSpace on 2012-07-27T17:07:55Z (GMT). No. of bitstreams: 1 dissertao corrigido final de ana carolina sampaio.pdf: 1962570 bytes, checksum: 530d0baf753727aa3bda4dcc7e937c68 (MD5) Previous issue date: 2010 / O objetivo deste trabalho foi descrever os principais eventos ocorridos durante o desenvolvimento inicial da matrinxã Brycon amazonicus, correlacionando-os com o comportamento alimentar apresentado pelas larvas no período de 24 a 240 h após a eclosão (HAE) ou 10 dias. O objetivo do primeiro capítulo foi descrever o desenvolvimento embrionário e larval da matrinxã, caracterizando os principais eventos ocorridos até 72 h após a fertilização (HAF). O trabalho foi desenvolvido na Estação de Piscicultura de Balbina Município de Presidente Figueiredo. A caracterização foi feita com base na análise estéreo-microscópica, morfométrica e comparação bibliográfica. Os ovos da matrinxã são livres, transparentes, esféricos com grande espaço perivitelínico (0,56 ± 0,3 mm). As sucessivas clivagens originam células com 64 blastômeros na primeira hora AF. A gástrula, iniciada 02 h e 40 min AF, caracterizou-se por progressiva involução celular e formação do eixo embrionário, culminando com diferenciação de cabeça e cauda, com 05 h e 30 min AF. A embriogênese teve duração de 3 h com formação de somitos, notocorda, vesículas óptica, ótica e otólitos, além de batimentos cardíacos e liberação da cauda. As larvas eclodiram com 10 h e 30 min AF, quando teve início o estágio larval, em temperatura média de 29,9ºC. As larvas eclodiram com 3,56 ± 0,46 mm de comprimento total. Entre 19 e 30 h após a fertilização (HAF) foram observadas: 1) pigmentação e formação do tubo digestivo 2) surgimento de arcos branquiais 3) nadadeira peitoral 4) abertura da boca e 5) surgimento dos dentes. O canibalismo foi iniciado às 34 HAF, com 5,7 ± 0,66 mm de comprimento total, abertura bucal 1,46 ± 0,19 mm e intensos movimentos mandibulares acompanhados de natação vertical. A larva está apta à natação, busca e apreensão de presas e escape de predadores desde 60 HAF, permitindo sua transferência aos viveiros de alevinagem. No segundo capítulo se objetivou conhecer a seletividade alimentar da matrinxã no período de 24 a 240 h após a eclosão (HAE). Foram ofertados diariamente uma mistura de organismos zooplanctônicos (50 organismos/larva) e ração. A mistura ofertada foi previamente quali e quantificada e as larvas alimentadas eram amostradas diariamente para verificação do conteúdo alimentar no trato digestório analisado sob estereomicroscópio. Não foi observada seleção por organismos menores (Rotíferos e náuplios) e não foi observada correlação entre as medidas morfométricas da larva e medidas da presa. Os resultados mostram seleção por alimento vivo, com preferência alimentar por Cladóceros até o décimo dia de vida. No terceiro capítulo foi avaliado o desempenho das larvas quando submetidas a diferentes tratamentos alimentares, no período de 28 a 100 HAE, sendo: T1 = ração; T2 = zooplâncton e T3 = Ração + zooplâncton. O T3 apresentou maior taxa de crescimento específico (TCE) (2,03) e comprimento (6,49 mm), contudo a sobrevivência não diferiu entre os tratamentos. As larvas iniciaram a ingestão de alimento vivo ou ração no período entre 40 e 43 HAE, quando restavam pequenas proporções da reserva endógena (vitelo), indicando início de alimentação exógena neste período e utilização do alimento vivo até 240 HAE. Diante dos resultados observados, acredita-se que um correto manejo alimentar deve considerar redução no período de incubação de 72 h para 40 h, quando as larvas deverão receber alimento vivo e treinamento alimentar para aceitação de ração até o 10º dia após a eclosão. Isto possivelmente proporcionará maiores taxas de sobrevivência na larvicultura. / The objective of this work was to describe the main events happened during the initial development of the matrinxã Brycon amazonicus, correlating them with the alimentary behavior presented by the larvae in the period from 24 to 240 h after hatching (HAH) or 10 days. The objective of the first chapter was to describe the embryonic and larval development of the matrinxã, characterizing the main events happened until 72 h after fertilization (HAF). The work was developed in Center of Tecnology, Training and Production in Aquaculture (CTTPA), in Balbina Municipal district of President Figueiredo. The characterization was made under stereomycroscopic analysis, morfometry and bibliographical comparison. The eggs of matrinxã are free, transparent, and spherical with a large perivitelline space (0.56 ± 0.3 mm). The successive clivages originate cells with 64 blastomeres in the first HAF. The gastrulation initiates at 02 h and 40 min AF, and was characterized by progressive cells involution and formation of the embryonic axis, culminating with differentiation of head and tail with 05 h and 30 min AF. The embriogenesis had duration of 3 h with somitos formation, notocord, optical vesicle, otics vesicle and otholits, besides heart beats and liberation of the tail. The larvae hatched at 10 h and 30 min AF, when it had beginning the apprenticeship, in medium temperature of 29.9ºC. Larvae total lengh at hatching was 3.56 ± 0.46 mm. Between 19 and 30 HAF they were observed: 1) pigmentation and formation of the digestory tube 2) appearance of branchial arches 3) fin peitoral 4) opening of the mouth and 5) appearance of the teeth. The cannibalism started at 34 HAF, with 5.7 ± 0.66 mm of total length, mouth opening 1.46 ± 0.19mm and intense jaw movements and vertical swimming. The larva is capable the swimming, it looks for and apprehension of preys and escape of predators, from 60 HAF, allowing your transfer to the nurseries ponds, reducing the incubation period. In the second chapter two the objective was to know de feeding selectivity of matrinxã larvae between 24 and 240 hours after hatching (HAH). Daily was offered a mixture of zooplanctonic organisms (50 organisms/larvae) and ration. The mixture was previously quantificated and qualificated and the feeding contents of larvae were analysed under estereomicroscopy. We didn´t observed selectivity for little items (rotifers and nauplians) and there wasn´t correlations between larvae and pray measurement. The results show selection for live food and preferences by Cladocera until tenth day of life. In the third chapter, it was evaluated the acting of the larvae when submitted to different alimentary treatments, in the period from 28 to 100 HAH, being: T1 = ration; T2 = zooplancton and T3 = Ration + Zooplancton. T3 presented larger specific growth rate (SGR) (2.03), and length (6,49 mm), however the survival didn't differ among the treatments. The larvae began the ingestion of alive food or ration bettween 40 and 43 HAH ages, when they remain small proportions of the endogenous reservation (vitelo). The results indicate beginning of the feeding exogen between 40 and 43 HAH and the use of the alive food up to 240 HAH. Before the observed results, we believed that a correct handling to feed it should consider reduction in the incubation period, from 72 to 40 h, when the larvae should receive alimentary training for ration acceptance, until the 10th day after appearance. So, may be possible to increase the survival rates during hatchery.
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72

Análise comparativa da expressão dos genes Dapper (Dpr) durante a ontogênese dos membros de camundongo (Mus musculus C57BL/6) e galinha (Gallus gallus) / Comparative analysis of Dapper (Dpr) gene expression during limbs ontogeny of mouse (Mus musculus C57BL/6) and chicken (Gallus gallus)

Sensiate, Lucimara Aparecida 18 August 2018 (has links)
Orientador: Lúcia Elvira Alvares / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Biologia / Made available in DSpace on 2018-08-18T00:32:50Z (GMT). No. of bitstreams: 1 Sensiate_LucimaraAparecida_M.pdf: 8827752 bytes, checksum: 66afd653eb6cf0a2ff14cc79c158cfc1 (MD5) Previous issue date: 2011 / Resumo: Dentre as moléculas envolvidas na sinalização molecular durante o desenvolvimento, têm papel de destaque aquelas envolvidas nas vias de sinalização Wnt e TGF-ß. Trabalhos demonstram que as proteínas Dapper (Dpr) são capazes de modular tais vias de sinalização. A família de genes Dpr é constituída por três componentes: Dpr1, Dpr2 e Dpr3 em peixe-zebra, camundongo e humanos e Dpr1 e Dpr2 em aves. Os genes Dpr têm sido associados a movimentos morfogenéticos durante a gastrulação, especificação do mesoderma, morfogênese do encéfalo, coração e olhos. Apesar da grande relevância desta família gênica para o desenvolvimento, pouco se sabe sobre o padrão de expressão de tais genes em mamíferos e aves. Este projeto de pesquisa teve como objetivo principal a caracterização do padrão de expressão dos genes Dpr ao longo do desenvolvimento embrionário de camundongo e com maiores detalhes, a caracterização do padrão de expressão dos genes Dpr durante a ontogênese dos membros em embriões de camundongo e galinha. O padrão de expressão foi determinado através de ensaios de hibridação in situ whole mount e em cortes de parafina. Para permitir comparações, hibridações in situ foram realizadas com marcadores para o desenvolvimento de cartilagem, tendão e músculo. Como resultado, observamos que os genes Dpr são expressos em seis domínios chave (tubérculo genital, membros, focinho, somitos, hérnia umbilical fisiológica e encéfalo) durante o desenvolvimento de camundongo. A análise do padrão de expressão sugere fortemente o envolvimento dos genes Dpr na ontogênese dos membros em embriões de galinha e camundongo. Contudo, a expressão destes genes é bastante diferente entre estes dois organismos. O gene Dpr1 parece estar envolvido com a formação de elementos da articulação e do pericôndrio durante o desenvolvimento dos membros em embriões de camundongo e galinha. O gene Dpr2 possui expressão bastante difusa durante o desenvolvimento dos membros em embriões de camundongo. Em contrapartida, na galinha, Dpr2 possui expressão localizada no blastema dos dígitos e articulações do autópode. O gene Dpr3 possui expressão difusa durante o desenvolvimento dos membros. Apesar disto, os domínios de expressão identificados sugerem que Dpr3 esteja relacionado com o desenvolvimento dos dígitos e articulações / Abstract: Among the molecules involved in molecular signaling during development, those involved in the Wnt and TGF-ß pathways are particularly important. Studies have shown that the Dapper protein family (Dpr) can modulate Wnt and TGF-ß signaling. The Dpr gene family consists of three members: Dpr1, Dpr2 and Dpr3 in zebrafish, mice and humans, and only two: Dpr1 and Dpr2, in birds. Dpr genes have been associated with morphogenetic movements during gastrulation, mesoderm specification, morphogenesis of the brain, heart and eyes. Despite the great relevance of this gene family during development, little is known about the expression pattern of the Dpr genes in mammals and birds. This research project had as main aims to characterize the expression pattern of the Dpr genes during mouse embryonic development and, in more detail, their expression during limb ontogenesis in mouse and chicken embryos. The expression pattern was determined by in situ hybridization in whole mount and in paraffin sections. To allow comparisons, were performed in situ hybridization with markers for the development of cartilage, tendon and muscle. Our results indicate that Dpr genes are expressed in six key areas (genital tubercle, limbs, nose, somites, brain and physiological umbilical hernia) during development of mouse. The expression pattern in the limbs strongly suggests that the Dpr genes work in limbs development in chicken and mouse embryos. However, the expression pattern of these genes is different in these two organisms. Dpr1 seems to be involved in joint and perichondrium formation during limb development in mouse and chicken embryos. For Dpr2, the expression was diffuse during limb development in mouse embryos. In contrast, chicken Dpr2 has localized expression in the digits and joints. Dpr3 gene has diffuse expression during limb development. However, its expression domains suggest that Dpr3 is related to digits and joints development / Mestrado / Biologia Celular / Mestre em Biologia Celular e Estrutural
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73

Efeito de quatro diferentes meios de cultura na qualidade morfologica de zigotos e embriões / Morphological differences in human zygotes and embryos cultured in different media

Cossiello, Raquel Di Falco 14 August 2018 (has links)
Orientador: Carlos Alberto Petta / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Ciencias Medicas / Made available in DSpace on 2018-08-14T05:22:09Z (GMT). No. of bitstreams: 1 Cossiello_RaquelDiFalco.pdf: 3774222 bytes, checksum: 96b4cbfa6f25f58d8240f552b5c83617 (MD5) Previous issue date: 2009 / Resumo: Objetivo: comparar os efeitos de quatro diferentes meios de cultura na morfologia dos zigotos e embriões. Materiais e métodos: estudo retrospectivo conduzido no Centro de Reprodução Humana de Campinas, em que 2.289 embriões de 319 ciclos de ICSI foram avaliados de setembro de 2006 a setembro de 2008. O protocolo longo foi usado para estimulação ovariana em todos os casos. Todos os oócitos foram cultivados em dois meios diferentes. O meio HTF (Irvine Scientific) foi usado como meio-padrão, enquanto que os meios Universal IVF Médium (Medicult), Global (LifeGlobal) e IVF-30 (Vitrolife) foram usados como secundários. A separação dos oócitos em meios diferentes foi realizada alternadamente após ICSI. A presença e a posição de pronúcleos e Nuclear Precusror Bodies (NPBs) foram checadas 18 a 20 horas após ICSI. Baseado na classificação descrita por Gianaroli et al., os zigotos foram identificados como: (A1) pronúcleos justapostos e centralizados com NPBs grandes e alinhados; (A2) pronúcleos justapostos e centralizados com NPBs grandes e dispersos. Os embriões foram avaliados 44 a 46 horas após ICSI, de acordo com o número de blastômeros, porcentagem de fragmentação e multinucleação. Os embriões considerados top apresentaram quatro blastômeros regulares, fragmentação menor que 20% do volume embrionário e blastômeros não multinucleados. Para a análise dos dados foram utilizados Z-test, odds ratio simples e múltiplo através de regressão logística com seu respectivo intervalo de confiança a 95%. Resultados: quando a classificação dos zigotos foi analisada, o meio IVF-30 mostrou maior porcentagem (55,2%) de zigotos A1+A2, em relação ao HTF, Global e Universal IVF Medium (49,1%, 44,7% e 44,2%, respectivamente). A porcentagem de embriões top foi significativamente maior no meio Global (40,4%) comparado com HTF (21,1%), IVF-30 (25,0%) e Universal IVF Medium (11,1%). No segundo dia de desenvolvimento, Medicult produziu mais embriões com três células em relação aos outros meios que produziram mais embriões com quatro células. Conclusão: Houve diferenças significativas entre os quatro meios de cultura sobre a morfologia dos zigotos e a morfologia embrionária. IVF-30 (Vitrolife) resultou em maior número de zigotos com pronúcleos centralizados e nucléolos justapostos e dispersos. Global (LifeGlobal) sustentou maior formação de embriões top no dia 2 e maiores taxas de clivagem em relação aos demais meios / Abstract: Objective: compare the effects of four different culture media on the quality of zygotes and embryos. Methods: This retrospective study, performed at the Center for Human Reproduction of Campinas-Brazil analyzed 2289 embryos were assessed from September 2006 to September 2008. Long protocol was used for ovarian stimulation in all cases. The oocytes of each patient were cultivated in two different culture media. The medium HTF - Irvine was set as the default for all cycles and IVF Medium - Medicult, GGG 20 - Global and IVF 30 - Vitrolife defined as secondary media. The sibling oocytes were divided in the two culture media after ICSI. The confirmation of fertilization and classification as described by Gianaroli were evaluated 18-20 hours after ICSI. On the second day (day 2) of development, the embryos were evaluated according the number of cells, percentage of fragmentation and number of nuclei. On day 2, the embryos that had four cells with less than 20% of fragmentation and were mononucleated embryos were classified as Top. Z-test and Odds ratios were used for statistical analysis. Results: IVF-30 showed a higher percentage (55.2) of zygotes A1 + A2 when compared to HTF, Global and Universal IVF Medium media (49.1%; 44.7%; 44.2% respectively) The percentage of Top embryos was significantly higher in Global medium (40.4%) compared to HTF (21.1%), IVF-30 (25.0%) and Universal IVF medium (11.1%). On day 2 Universal IVF Medium produced more embryos with three blastomeres when compared to other media that produced more embryos with four blastomeres. Conclusions: The use of IVF- 30 medium resulted in a higher number of zygotes with centralized pronuclei with juxtaposed or scattered nucleoli. Meanwhile, Global medium produced a greater number of morphologically good embryos (TOP) and higher cleavage rate on the second day of development / Universidade Estadual de Campi / Tocoginecologia / Mestre em Tocoginecologia
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74

Exploration of Ataxia Telangiectasia and Rad3-Related’s (ATR’s) Role in Cell Death Regulation: Implications in Development, Cancer, and Stroke

Cartwright, Brian 01 December 2019 (has links)
From gametogenesis until death an organism’s genome is under constant bombardment from endogenous and exogenous sources of DNA damage. To maintain genomic integrity amid this damage, cells have evolved responses which allow them to either preserve viability for recovery or initiate self-destructive pathways depending on the severity of DNA damage. One protein involved in initiating and carrying out these responses is the protein kinase ataxia telangiectasia and Rad3-related (ATR). ATR is known primarily for its regulatory role in initiating the checkpoint-signaling cascade following DNA damage and replicative stress. These signaling events lead to cell cycle arrest, DNA repair, or apoptosis when damage is too extreme. In addition to these kinase-dependent roles, ATR also is capable of directly blocking the intrinsic apoptotic pathway through structural sequestration of the proapoptotic protein tBid. The sum of these regulatory events is a delicate balancing act resulting in either cell death or cell survival depending on the severity of the damage and the differentiation state of the cell in question. In the following studies, we sought to investigate the complex interplay of ATR’s kinase and structural roles in determining cellular fate. First, we investigated the structural role of prolyl isomerization of ATR across development by using mouse models of two isomerically locked forms of ATR which were previously shown to lock cytoplasmic ATR into a single isomer. Studies showed that ATR which is locked in ATR-L (trans-ATR, hATR-P429A/mATR-P432A) is embryonically lethal and that heterozygotes tend to have neurological and other developmental abnormalities. This contrasts with ATR-H (cis-ATR, hATR-S428A/mATR-S431A), which is viable, but naturally prone to cancer development. Next, we used various in vitro stroke-like conditions to test if ATR inhibition could serve as a therapeutic target for stroke. We found that ATR inhibition is protective in non-dividing neuron-like cells; whereas, it potentiates death in cycling glial and immune-like cycling cells. Thus, ATR inhibition could likely be a target for both neuron sparing and immunosuppressive anti-stroke therapeutic strategies. Taken together, these studies provide insightful information into the structural and pathological roles of ATR in development and disease.
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75

Cortical patterning in syncytial embryos: the link between microtubules and actin cortex

Li, Long 16 December 2019 (has links)
No description available.
76

Significant increase in liver and heart mass found in post hatching red junglefowls (Gallus gallus).

Pedersen, Frederik January 2021 (has links)
Significant heart and liver increase in hatching and neonates has been found evident in multiple different species such as the emu, Peking Duck, and pigs. The relative mechanism behind heart growth could be tied to closing of the ductus arteriosus, however there is still a debate whether it’s significant impact in avian species. Liver and heart mass were measured at four different transition stages before and after hatching on Red junglefowls (Gallus gallus). Heart mass was found to vary between 83-170mg, with the lowest values most often found in pre pipped chickens while higher values found more often in hatchlings. The relative heart mass was found to be significant (P<0,05) across all groups except between internally pipped and externally pipped chickens. Therefore, the results can conclude that an increase in relative heart mass was found to be directly tied to age. Liver mass was found to be significant (P<0,05) but changes in mass was found to occur only between EP and hatchling stage. Further analysis on absolute heart and liver mass showed in both cases hatchlings having a higher mean mass compared to the other three stages. Both absolute liver and heart mass was found to be statistically significant (P<0,05) which indicates there are no major differences between analysis on relative or absolute mass. These findings suggest that red junglefowls follow the same growth pattern found in other precocial birds such as emu or Peking duck.
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77

Characterization of the Visceral Endoderm Components in Early Post-Implantation Mouse Embryo Development: A Dissertation

Huang, Tingting 28 February 2014 (has links)
Early post-implantation vertebrate embryos are shaped by complex cellular and molecular mechanisms. In mice, the visceral endoderm, an extraembryonic cell lineage that appears before gastrulation, provides several important functions such as nutrition and mechanical protection. My thesis research focused on the role of the visceral endoderm in embryo patterning, a newly discovered function for this tissue. My results showed that an interplay between two subpopulations of visceral endoderm the anterior and posterior visceral endoderm, located on the opposite sides of the developing conceptus, are critical for the establishment of the anteroposterior body axis of the embryo. I also found that senescence-associated β-galactosidase activity delineates the visceral endoderm marking apical vacuole, a lysosomal-like organelle. This however indicates the nutritional function of visceral endoderm cells rather than a senescent population. My studies highlight the fundamental role of extraembryonic tissues in patterning mammalian embryos as opposed to housekeeping roles. They also reveal important difference when conducting studies at the organismal level rather than in cells in culture.
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78

The impact of cyclophosphamide on male germ cell quality and consequences on early post-fertilization events /

Barton-Maclaren, Tara S. January 2007 (has links)
No description available.
79

Classics Revisited, History of Reptile Placentology, Part IV: Hanni Hrabowski's 1926 Monograph on Fetal Membranes of Lizards

Stewart, James R., Blackburn, Daniel G. 01 June 2020 (has links)
In 1926, the German biologist Johanna (Hanni) Hrabowski published a study of the morphology and development of the fetal placenta in lizards that has proven to be of historical importance. Her anatomical descriptions and interpretations identified developmental patterns that differ from other amniotes – features now recognized as unique attributes of squamate (lizards and snakes) development. Her 1926 monograph presented the first histological comparison of fetal membranes in closely-related oviparous and viviparous reptiles, thereby establishing a comparative framework for understanding placental specializations for viviparity. Hrabowski reported that yolk sac development did not differ between oviparous and viviparous species. The novel, shared components of yolk sac development she identified are now recognized as the foundation for the unique yolk sac placenta of reptiles, the omphaloplacenta. In addition, Hrabowski's extensive ontogenetic sampling and the detail and accuracy of her anatomical descriptions set high standards for subsequent studies of comparative evolutionary embryology.
80

Dissolved Organic Matter Influences the Timing of Embryonic Development of the Purple Sea Urchin, Strongylocentrotus purpuratus.

Hodges, Corbin J 01 December 2009 (has links) (PDF)
Marine dissolved organic matter (DOM) comprises one of the largest carbon reservoirs on earth and has long been considered a potential energy source for marine invertebrates. The importance of DOM transport has been adequately demonstrated for unicellular organisms, where DOM can meet 100% of an organisms energy needs, but the effects of DOM uptake for marine metazoans are less well understood. In this study, three general areas involving the influence of DOM transport to marine invertebrates were explored. First, we assessed the effects of using seawater exposed to high intensity ultraviolet radiation (UVR) on the study organism; embryos of the purple sea urchin, Strongylocentrotus purpuratus. This was important because we used seawater treated in this way to create water types used in the experiments. Exposing seawater to high intensity UVR oxidizes (and functionally removes) DOM in the seawater. Second, the influence of the presence of DOM on the timing of embryonic development was examined for embryos of S. purpuratus. Specifically, the time of cell division and the time of hatching were determined for embryos in seawater with and without DOM. Finally, the ability of DOM to moderate the negative effect of UV-exposure on time of cell division was assessed. To make these comparisons experiments were performed using three water types: FSW (0.22 micron filtered seawater), DOM-depleted seawater (UV oxidized 0.22 micron filtered seawater), and DOM-enriched seawater (UV oxidized 0.22 micron filtered seawater enriched with labile DOM). In the first experiment, batches of embryos in the three water types were either exposed or not exposed to ultra-violet radiation and the time of first cell division was compared for embryos across the six treatments. In the second experiment, batches of embryos were placed in the same three water types and the time of first cell division and the time of hatching were quantified. From these experiments several results were generated. First, seawater exposed to high intensity UVR did not influence the timing of development of embryos of S. purpuratus. Embryos in water exposed to high intensity UVR (DOM-enriched and DOM-depleted seawater) hatched at similar times and completed first cell division at times similar to embryos in water not exposed to high intensity UVR (FSW). Next, we found that the influence of the presence of DOM on the development timing of S. purpuratus embryos depended on the event that was examined. The time of first cell division was not affected by the presence of DOM but the time of hatching was. Embryos in water with dissolved organic matter hatched on average 86 minutes later than embryos in water without DOM. Potentially, embryos in seawater without DOM speed up development to more quickly reach the point that they can feed on particulates. Lastly, the presence of DOM did not influence UVR-induced cleavage delay. The percent cleavage delay was not significantly different for embryos in seawater with (DOM-enriched) and without (DOM-depleted) DOM. In addition to the experiments, all studies in the literature that examine the realized effects of DOM transport were analyzed to ascertain when the manifestation of DOM uptake is most likely to occur. From these results, it appears that the effects of DOM transport are most likely to manifest after the life stage in which the majority of uptake occurred. If DOM transport has an affect within a life stage it is most likely to manifest as moderation of biomass loss or maintenance of endogenous reserves. With the addition of the experimental results from this study to the information already in the literature we begin to more fully grasp the importance of DOM transport to S. purpuratus. DOM influences the time of hatching, biomass, arm length, and stomach size of the species; results that highlight the importance of examining multiple affects of DOM transport for a single species. In conclusion, future research should look for multiple effects of the presence of DOM both within and across life stages (for a single species) to better understand the importance of DOM to marine invertebrates.
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