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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.
1

Studies on the occurrence, physiology, and ecology of bioluminescence in dinoflagellates

Esaias, Wayne E. 25 September 1972 (has links)
To provide further information on the occurrence and geographical variations of bioluminescent capabilities of marine dinoflagellates, forty species, representing twelve genera, of dinoflagellates from Yaquina Bay, Oregon, were examined for bioluminescence as single cell isolates. Seventeen species from the genera Ceratium (1 sp.), Gonyaulax (3 sp.), and Peridinium (13 sp.) were found to be bioluminescent. Ceratium fusus was the only member of the genus found to emit light; G. triacantha was found to be non-bioluminescent. The total photon emission of each luminescent species is reported. Values ranged from 1.05 x 10¹⁰ photons per P. depressum to 2.1 x 1O⁷ photons per G. digitale. As a taxon, the genus Peridinium emitted more light by an order of magnitude than did Ceratium or Gonyaulax. Comparisons with previous reports are made. Photoinhibition of the mechanical receptor mechanism is largely responsible for orders of magnitude diel variations of stimulable bioluminescence in the auxotrophic dinoflagellates. The mechanically stimulable bioluminescence of members of the Gonyaulax catenella group can be photoinhibited completely by exposure to as little as 10¹³ quanta/cm² delivered as a pulse of width between 0.1 and 10 seconds. There is an initial time lag of one minute, followed by a first order decay to approximately one percent of the bioluminescence of unexposed controls. The half time of this decay is only 50 seconds. Action spectra for photoinhibition in Gonyaulax catenella, G. acatenlla, and G. tamarensis revealed a single absorption band with a maximum at 562 nm. Photoinhibition appears to raise the threshold of sensitivity of the shear receptor mechanism. Chemically stimulable bioluminescence is unaffected by these brief exposures to light. Grazing experiments were conducted with three calanoid copepods and three species of bioluminescent dinoflagellates, using procedures which yielded samples of cultures with high and low capacities for mechanically stimulable bioluminescence. In all cases the ingestion rates were lower for the high bioluminescent capacity samples than for the samples having a reduced bioluminescent capacity. These results indicate that dinoflagellate bioluminescence has survival value as a defense against copepod grazing. Of several possible mechanisms, we propose that the flash is a visual, protean display which startles or confuses the copepod sufficiently to allow the dinoflagellate to escape. The net evolutionary value is that predation would be reduced on a dinoflagellate population as a whole. / Graduation date: 1973
2

Use of lux-marked rhizobacteria to investigate rhizosphere C-flow

Porteous, Fiona January 1998 (has links)
The aim of this study was to develop a protocol for the use of a lux-marked pseudomonad for the investigation of rhizosphere C-fluxes, and then use this to examine a system experiencing change in C flow due to pollutant pressure. In this study a typical rhizobacterium, Pseudomonas fluorescens, was marked by the insertion of the lux gene cassette of Vibrio fischeri. Two constructs were produced, P. fluorescens pUCD607 (marked with the full lux gene cassette of CDABE) and P. fluorescens FAC510 (chromosomally marked with the lux AB genes), both with bioluminescence directly linked to metabolic activity. The bioluminescence response of C-starved suspensions of these constructs to typical rhizosphere C substrates, was determined by exposure of the cells to substrate over a 30 minute period. It was shown that P. fluorescens pUCD607 can distinguish between substrate type and concentration, in terms of bioluminescence. In terms of Michaelis-Menten kinetics, glucose had a Km of 30.4mMC, and a Vmax of 200 RLU's/mMC. However, an amino acid (glutamic acid) produced a Vmax of 23316 RLU's/mMC, and a Km of 1mMC. Succinic acid, an organic acid, caused a much lower Vmax in P. fluorescens pUCD607 of 240 RLU's/mMC, and a Km of 2.5mMC. Clearly, this reporter construct offers great potential for modelling rhizosphere C-flow, as indicated by the data shown. Following this, P. fluorescens pUCD607 was used to investigate the effects of pollutant stress on rhizosphere C-flow. Plantago lanceolata was treated with paraquat and sodium arsenate, two common soil pollutants. Both caused an increase in root exudate C from 20-350%, depending on application time and concentration. P. fluorescens pUCD607 was able to detect this change, with bioluminescence directly correlated to actual C concentration. This study demonstrates that P. fluorescens pUCD607 offers a valuable tool for the reliable investigation of rhizosphere C-flow, and that lux gene technology offers the potential to further model the rhizosphere. This novel technique opens up many possibilities for applications in monitoring of ecosystem health, organic agriculture and bioremediation.
3

Contribuição ao estudo de espécies brasileiras de elaterídeos luminescentes: bioluminescência, metabolismo radicalar de oxigênio e digestão extra-corpórea / Contribution the study of Brazilian species of luminescent elateridae: bioluminescence, oxygen radical metabolism and digestion extracorporeal

Colepicolo, Pio 29 August 1986 (has links)
Esta tese contem dados biológicos, ecológicos e bioquímicos de quatorze espécies brasileiras de elaterídeos luminescentes, distribuídos em duas tribos. Os insetos foram coletados de vários habitats e criados em laboratório, em colaboração com pesquisadores do Museu de Zoologia da USP. Demonstramos inicialmente que todos os elaterídeos estudados contêm a mesma luciferina de lampirideos, independentemente da natureza da lanterna (toráxica ou abdominal) e do estágio metamórfico. Estudos da biossíntese da luciferina a partir de 14C-cistina mostraram um rendimento radioquímico de síntese da ordem de 4%. Verificamos que cada espécie tem um λmax de bioluminescência característico, o que pode ter importância taxonômica, especialmente no caso de larvas. Estudo físico-químico (\"in vitro\") da luciferase mostrou a possível existência de isozimas de luciferase nas fases da metamorfose e nas lanternas abdominal e toráxica. A intensidade de emissão por ovos e larvas aumenta logarítmicamente com o aumento da temperatura absoluta, o que deve ter importância no mecanismo de caça das larvas. Ênfase especial foi dada ao Pyrearinus termitilluminans, espécie inquilina dos conhecidos \"cupinzeiros luminescentes\" encontrados no cerrado do Brasil Central e na bacia amazônica; descreve-se o processo de infestação dos cupinzeiros, usando-se observações de campo e moldagens das galerias com poliestireno. Uma conexão interessante foi constatada entre a bioluminescência e a produção de radicais de oxigênio, acompanhada por medidas de níveis de superóxido dismutase (SOD), ao comparar-se elaterídeos luminescentes e não-luminescentes da mesma tribo e ao comparar-se os segmentos abdominais e toráxicos de larvas de Pyrearinus termitilluminans. É também interessante notar que larvas de elaterídeos habitantes de troncos em apodrecimento (onde a concentração do oxigênio < 2%) possuem menor atividade da enzima antioxidante SOD que larvas de Pyrearinus termitilluminans, encontradas nas galerias aeradas dos cupinzeiros. Discute-se possíveis mecanismos de estocagem de oxigênio nas larvas luminescentes. Finalmente descobrimos que o regurgitado injetado pelas larvas de elaterídeos nas suas presas é fortemente tamponado em pH 7,3 e contém urna mistura de proteinases (tripsina e aminopeptidase) e carbohidrases (amilase, celulase, celobiase, maltase e trealase). A injeção deste coquetel enzimático imobiliza a presa e executa digestão pré-oral. As enzimas citadas foram caracterizadas por parâmetros físico-químicos (atividade específica, pH ótimo, pI, Mw, Km e migração eletroforética relativa) e mapeadas no interior do tubo digestivo das larvas. Os dados enzimaticos são tentativamente utilizados para análise filogenética destes insetos. / This thesis contains biological, ecological and biochemical data of fourteen species of Brazilian luminescent Elateridae (two tribes, four genera). The insects were collected in different habitats and reared from eggs in laboratory at the Museu de Zoologia da Universidade de São Paulo. Thin layer chromatography revealed that the luciferin from the elaterid species, at different stages of development and from either the thoracic or abdominal lanterns, is the same as that of Lampyridae. The radiochemical yield of luciferin biosynthesis from the precursor 14C-cystine, is ca 4%. In vivo and in vitro bioluminescence spectra are characteristic for each species and probably can be used as a tool in taxonomy, specially in the case of the larvae. Physical-chemical studies point to the possible existence of luciferase isozymes in the abdominal and thoracic lanterns of adult Pyrophorus divergens. The bioluminescence intensity from Pyrearinus termitilluminans eggs and larvae increases sharply upon increasing the temperature. We also describe the infestation process of the \"luminous\" termite mounds (found in the \"cerrados\" of Central Brazil and in the Amazonian basin) on basis of field observations and polymer-molds of the mound galleries. There is an interesting conection between bioluminescence and the oxygen radical production when compared the levels of superoxide dismutase (SOD) and catalase (two antioxidant enzyme) in luminescent and non-luminescent elaterids. SOD levels were found to be higher in luminescent insects. For luminescent larvae, a direct correlation between SOD activity and brightness from the segments of their body was observed. In addition, larvae of Pyrearinus termitilluminans (inhabiting aerated galleries) have higher SOD activity than Pyrophorus divergens (dwelling decaying logs). These results are interpreted in terms of SOD protection against deleterious effects of active oxygen arising from storage of molecular oxygen to sustain the bioluminescent reaction. Finally we discovered that the dark liquid regurgited by larval elaterids and injected onto their preys is highly buffered in pH 7,3 and contains a mixture of hydrolases (trypsin, aminopeptidase, amylase, cellulase, cellobiase, maltase and trehalase). The injection of this liquid immobilizes the prey and perform the pre-oral digestion. These enzymes were characterized by physico-chemical parameters (specific activity, optimum pH, pI, Mw, Km and electrophoretical relative migration) and mapped in the midgut cells. The enzymatic data is tentatively used for phylogenetical analysis of these insects.
4

Ecological significance of dinoflagellate bioluminescence

Esaias, Wayne E. 31 October 1969 (has links)
The nature of the bioluminescence of Gonyaulax catenella is similar to that observed for other dinoflagellates in culture, showing photoperiod-entrained rhythms of luminescence and stimulability with relatively constant luminescent capacity during scotophase. G. catenella is very sensitive to stimulation and photoinbibition. The nature of the response to stimulation by bubbling appears similar to that of G. polyedra, and comparisons of the total stimulable light with G. polyedra indicate that G. catenella emits approximately 6 x 10⁷ photons per cell, during exhaustive scotoptic stimulation. Over a range of cell concentrations, the rates of cell removal and filtration for Calanus pacificus when grazed on G. catenella were considerably lower when the dinoflagellates were in a relatively non-luminescent phase as opposed to a highly sensitive and luminescent phase. These differences could not be attributed to differences in particle size, culture age, distribution of dinoflagellates, ambient light intensity, rhythms in copepod feeding activity, or other factors reported to affect copepod grazing. Possible mechanisms of the effect are discussed. It is proposed that bioluminescence in dinoflagellates serves as a protean display type of defense mechanism against copepod grazing, has selective value, and is of adaptive and ecological significance. / Graduation date: 1970
5

Evolution of the glow-signal system in Microphotus (Coleoptera, Lampyridae)

Cicero, Joseph Michael January 1981 (has links)
No description available.
6

Studies of myoplasmic ATPMg in barnacle muscle fibers with the firefly method

Chiang, Linda Kuolin. January 1980 (has links)
Thesis (M.S.)--University of Wisconsin--Madison. / Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 187-201).
7

Long term and seasonal changes in dinoflagellate bioluminescence in the Southern California Bight

Lapota, David, Unknown Date (has links)
Thesis (Ph. D.)--University of California, Santa Barbara, 1998. / Vita. Includes bibliographical references.
8

Stimulation of bioluminescence in Pyrocystis lunula and Gonyaulax polyedra by means of controlled pressure changes

Donaldson, Thomas Quinton. January 1982 (has links)
Thesis (M.S.)--Naval Postgraduate School, 1982. / Includes bibliographical references (leaves 66-71).
9

Contribuição ao estudo de espécies brasileiras de elaterídeos luminescentes: bioluminescência, metabolismo radicalar de oxigênio e digestão extra-corpórea / Contribution the study of Brazilian species of luminescent elateridae: bioluminescence, oxygen radical metabolism and digestion extracorporeal

Pio Colepicolo 29 August 1986 (has links)
Esta tese contem dados biológicos, ecológicos e bioquímicos de quatorze espécies brasileiras de elaterídeos luminescentes, distribuídos em duas tribos. Os insetos foram coletados de vários habitats e criados em laboratório, em colaboração com pesquisadores do Museu de Zoologia da USP. Demonstramos inicialmente que todos os elaterídeos estudados contêm a mesma luciferina de lampirideos, independentemente da natureza da lanterna (toráxica ou abdominal) e do estágio metamórfico. Estudos da biossíntese da luciferina a partir de 14C-cistina mostraram um rendimento radioquímico de síntese da ordem de 4%. Verificamos que cada espécie tem um λmax de bioluminescência característico, o que pode ter importância taxonômica, especialmente no caso de larvas. Estudo físico-químico (\"in vitro\") da luciferase mostrou a possível existência de isozimas de luciferase nas fases da metamorfose e nas lanternas abdominal e toráxica. A intensidade de emissão por ovos e larvas aumenta logarítmicamente com o aumento da temperatura absoluta, o que deve ter importância no mecanismo de caça das larvas. Ênfase especial foi dada ao Pyrearinus termitilluminans, espécie inquilina dos conhecidos \"cupinzeiros luminescentes\" encontrados no cerrado do Brasil Central e na bacia amazônica; descreve-se o processo de infestação dos cupinzeiros, usando-se observações de campo e moldagens das galerias com poliestireno. Uma conexão interessante foi constatada entre a bioluminescência e a produção de radicais de oxigênio, acompanhada por medidas de níveis de superóxido dismutase (SOD), ao comparar-se elaterídeos luminescentes e não-luminescentes da mesma tribo e ao comparar-se os segmentos abdominais e toráxicos de larvas de Pyrearinus termitilluminans. É também interessante notar que larvas de elaterídeos habitantes de troncos em apodrecimento (onde a concentração do oxigênio < 2%) possuem menor atividade da enzima antioxidante SOD que larvas de Pyrearinus termitilluminans, encontradas nas galerias aeradas dos cupinzeiros. Discute-se possíveis mecanismos de estocagem de oxigênio nas larvas luminescentes. Finalmente descobrimos que o regurgitado injetado pelas larvas de elaterídeos nas suas presas é fortemente tamponado em pH 7,3 e contém urna mistura de proteinases (tripsina e aminopeptidase) e carbohidrases (amilase, celulase, celobiase, maltase e trealase). A injeção deste coquetel enzimático imobiliza a presa e executa digestão pré-oral. As enzimas citadas foram caracterizadas por parâmetros físico-químicos (atividade específica, pH ótimo, pI, Mw, Km e migração eletroforética relativa) e mapeadas no interior do tubo digestivo das larvas. Os dados enzimaticos são tentativamente utilizados para análise filogenética destes insetos. / This thesis contains biological, ecological and biochemical data of fourteen species of Brazilian luminescent Elateridae (two tribes, four genera). The insects were collected in different habitats and reared from eggs in laboratory at the Museu de Zoologia da Universidade de São Paulo. Thin layer chromatography revealed that the luciferin from the elaterid species, at different stages of development and from either the thoracic or abdominal lanterns, is the same as that of Lampyridae. The radiochemical yield of luciferin biosynthesis from the precursor 14C-cystine, is ca 4%. In vivo and in vitro bioluminescence spectra are characteristic for each species and probably can be used as a tool in taxonomy, specially in the case of the larvae. Physical-chemical studies point to the possible existence of luciferase isozymes in the abdominal and thoracic lanterns of adult Pyrophorus divergens. The bioluminescence intensity from Pyrearinus termitilluminans eggs and larvae increases sharply upon increasing the temperature. We also describe the infestation process of the \"luminous\" termite mounds (found in the \"cerrados\" of Central Brazil and in the Amazonian basin) on basis of field observations and polymer-molds of the mound galleries. There is an interesting conection between bioluminescence and the oxygen radical production when compared the levels of superoxide dismutase (SOD) and catalase (two antioxidant enzyme) in luminescent and non-luminescent elaterids. SOD levels were found to be higher in luminescent insects. For luminescent larvae, a direct correlation between SOD activity and brightness from the segments of their body was observed. In addition, larvae of Pyrearinus termitilluminans (inhabiting aerated galleries) have higher SOD activity than Pyrophorus divergens (dwelling decaying logs). These results are interpreted in terms of SOD protection against deleterious effects of active oxygen arising from storage of molecular oxygen to sustain the bioluminescent reaction. Finally we discovered that the dark liquid regurgited by larval elaterids and injected onto their preys is highly buffered in pH 7,3 and contains a mixture of hydrolases (trypsin, aminopeptidase, amylase, cellulase, cellobiase, maltase and trehalase). The injection of this liquid immobilizes the prey and perform the pre-oral digestion. These enzymes were characterized by physico-chemical parameters (specific activity, optimum pH, pI, Mw, Km and electrophoretical relative migration) and mapped in the midgut cells. The enzymatic data is tentatively used for phylogenetical analysis of these insects.
10

Applications of the bacterial luciferin-luciferase system

Chan, Wai Shing 01 January 2012 (has links)
No description available.

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