共查询到20条相似文献，搜索用时 10 毫秒
1.
Evidence for sexual reproduction was observed in two oceanic dinoflagellate species, Pyrocystis noctiluca Murray ex Haeckel and Pyrocystis lunula (Schütt) Schütt. Observations suggest that cells underwent fertilization as opposed to cell division because of the following: first, fusing cells had a conspicuous pore (fusion pore) connecting the two gametes; dividing cells lacked this feature. In culture, about 0.1% of P. noctiluca cells had a fusion pore, which serves as a possible site for gamete recognition on the cell wall. Second, we document a temporal progression of plasmogamy and karyogamy. Fusion events in both species were observed at the beginning of the day, whereas division stages were most apparent at the end of the day. 相似文献
2.
Abstract Pyrocystis lunula, a dinoflagellate lacking periodicity in spontaneous bio‐luminescence, shows a characteristic circadian rhythm of plastid movements which can be monitored photographically in individual cells. The rhythm persists under free‐running conditions in constant dim light (40–50 Ix), but is damped out already in LL of 100 lx. 相似文献
3.
由于生活史特殊以及分类学历史复杂, 国内外有关梨甲藻科物种的分类学研究比较少。本研究通过形态分类学方法, 详细阐述了梨甲藻物种的分类学历史沿革, 对我国海域的11种梨甲藻科物种的孢囊进行了分类学研究。我们认为其中的1种应隶属于球甲藻属(Dissodinium), 其余10种可归为梨甲藻属(Pyrocystis)(包括2个变种, 2个变型), 对每个物种都进行了详细的形态学描述, 认为拟新月球甲藻(Dissodinium pseudolunula)与新月梨甲藻(Pyrocystis lunula)、优美梨甲藻(Pyrocystis elegans)与粗梨甲藻(Pyrocystis robusta)的分类学关系还需要进一步研究。 相似文献
4.
Beatrice M. Sweeney 《Journal of phycology》1982,18(3):412-416
The large dinoflagellate, Pyrocystis fusiformis Murray, emits biolumtnescence on stimulation with dilute acid. The bioluminescence can be seen in the light microscope to originate in a spherical region just distal to the nucleus during the day and appears as a persistent glow which can be localized in an orange-brown sphere. At night, the bioluminescence, in response to stimulation, is a bright flash from microsources scattered throughout the cytoplasm. The orange sphere can no longer be seen nor does a bioluminescent glow originate from this central region on stimulation. This difference in the position of intracellular bioluminescence between day and night has allowed the identification in electron micrographs of structures which correspond to the source of bioluminescence during the day. Light is emitted from a spherical mass of vesicles which contain electron-dense short rods with rounded ends, sometimes crossed by electron-transparent narrow bands. At night, these vesicles can be recognized in the peripheral cytoplasm. It is proposed that these vesicles are the structural counterparts of the microsources of bioluminescence in P. fusiformis. 相似文献
5.
Bioluminescent dinoflagellates are flow-sensitive marine organisms that produce light emission almost instantaneously upon stimulation by fluid shear in a shear stress dose-dependent manner. In the present study we tested the hypothesis that monitoring bioluminescence by suspended dinoflagellates can be used as a tool to characterize cellular response to hydrodynamic forces in agitated bioreactors. Specific studies were performed to determine: (1) impeller configurations with minimum cell activation, (2) correlations of cellular response and an integrated shear factor, and (3) the effect of rapid acceleration in agitation. Results indicated that (1) at a volumetric mass transfer coefficient of 3 x 10(-4) s(-1), marine impeller configurations were less stimulatory than Rushton configurations, (2) bioluminescence response and a modified volumetric integrated shear factor had an excellent correlation, and (3) rapid acceleration in agitation was highly stimulatory, suggesting a profound effect of temporal gradients in shear in increasing cell stimulation. By using bioluminescence stimulation as an indicator of agitation-induced cell stimulation and/or damage in microcarrier cultures, the present study allows for the verification of hypotheses and development of novel mechanisms of cell damage in bioreactors. 相似文献
6.
Rosemarie Knaust Thomas Urbig Liming Li Walter Taylor J. Woodland Hastings 《Journal of phycology》1998,34(1):167-172
The biochemistry and circadian regulation of luminescence in two Pyrocystis species, P. lunula Hulburt and P. noctiluca Murray et Haeckel, were compared with a well-studied species, Gonyaulax polyedra Stein. All exhibit circadian rhythms and all have similar luciferins and luciferases. However, the Pyrocystis species lack a second protein involved in the reaction in Gonyaulax , the luciferin (substrate) binding protein, which sequesters the luciferin at the cytoplasmic pH and releases it upon acidification, thus controlling the characteristic flashing, which is similar in the three species. More striking is the difference in the circadian regulation of luminescence, which in Gonyaulax involves the daily synthesis and destruction of the two proteins, along with the luminous organelles (scintillons) from which light is emitted, and which are present in all species. In the Pyrocystis species, the amount of luciferase is the same in extracts made during the day and night phases; its circadian regulation in vivo may be attributed to a change in its localization from day to night phase. 相似文献
7.
Andrea Baker Ian Robbins Mark A. Moline María Débora Iglesias‐Rodríguez 《Journal of phycology》2008,44(2):419-428
Bioluminescence is reported in members of 18 dinoflagellate genera. Species of dinoflagellates are known to have different bioluminescent signatures, making it difficult to assess the presence of particular species in the water column using optical tools, particularly when bioluminescent populations are in nonbloom conditions. A “universal” oligonucleotide primer set, along with species and genus‐specific primers specific to the luciferase gene were developed for the detection of bioluminescent dinoflagellates. These primers amplified luciferase sequences from bioluminescent dinoflagellate cultures and from environmental samples containing bioluminescent dinoflagellate populations. Novel luciferase sequences were obtained for strains of Alexandrium cf. catenella (Whedon et Kof.) Balech and Alexandrium fundyense Balech, and also from a strain of Gonyaulax spinifera (Clap. et Whitting) Diesing, which produces bioluminescence undetectable to the naked eye. The phylogeny of partial luciferase sequences revealed five significant clades of the dinoflagellate luciferase gene, suggesting divergence among some species and providing clues on their molecular evolution. We propose that the primers developed in this study will allow further detection of low‐light‐emitting bioluminescent dinoflagellate species and will have applications as robust indicators of dinoflagellate bioluminescence in natural water samples. 相似文献
8.
Pyrocystis lunula Schütt is a unicellular photoautotrophic dinoflagellate, commonly found in marine environments, displaying circadian‐controlled bioluminescence. Because of this species' characteristics, effects of pollutants on bioluminescence in P. lunula may make for an easy and simple bioassay that would be valuable for toxicity testing and the protection of coastal resources. This study therefore investigated the short‐term effects of metals and organic pollutants on the recovery of the bioluminescent potential in P. lunula. Recovery of bioluminescence was strongly inhibited in a dose‐dependent manner by all reference contaminants tested, the system being most sensitive to copper and cadmium (4‐h IC50s 0.96 and 1.18 μM, respectively), followed by phenanthrene, lead, SDS, and nickel (4‐h IC50s 1.64, 12.8, 15.6, and 73.1 μM, respectively), whereas relatively high concentrations of phenol were needed to elicit a response (4‐h IC50 1.64 mM). Except for exposure to lead and nickel, the inhibitory effects of cadmium, copper, and all organic pollutants were reversible, with P. lunula recovering 80%–100% of its bioluminescence potential after a period of 72 h in uncontaminated medium. Our results show that the restoration of bioluminescence in P. lunula is sensitive to the reference contaminants tested and obtains highly reproducible results. 相似文献
9.
Pyrocystis lunula (Schutt) Schutt has long been a model cell system in the study of circadian rhythms of bioluminescence and photosynthesis. Despite this, relatively little is known about the cell's ultrastructure. Here we report the complete serial reconstruction of P. lunula cells during both day and night phases (the first four dimensional study of any dinoflagellate). This permitted us to track both positional and ultrastructural changes in plastids and scintillons (the organelles responsible for bioluminescence). In daytime cells, plastids extended radially from the cell center with thylakoid membranes in stacks of two. Daytime scintillons clustered in a central region of the cell surrounded by the C-shaped nucleus. During the night, plastids were closely associated in the cell center with their thylakoids stacked in a grana-like arrangement. Nighttime scintillons were spread into the cell periphery. The daily migration of plastids and scintillons may depend on these organelles' interactions with the cells' cytoskeletal framework and appears to be under control of the circadian clock. 相似文献
10.
Dinoflagellates are the most abundant protists that produce bioluminescence. Currently, there is an incomplete knowledge of the identity of bioluminescent species arising from inter‐ and intraspecific variability in bioluminescence properties. In this study, PCR primers were designed to amplify the dinoflagellate luciferase gene (lcf) from genetically distant bioluminescent species. One of the primer pairs was “universal,” whereas others amplified longer gene sequences from subsets of taxa. The primers were used to study the distribution of lcf and assess bioluminescence potential in dinoflagellate strains representing a wide variety of taxa as well as multiple strains of selected species. Strains of normally bioluminescent species always contained lcf even when they were found not to produce light, thus demonstrating the utility of this methodology as a powerful tool for identifying bioluminescent species. Bioluminescence and lcf were confined to the Gonyaulacales, Noctilucales, and Peridiniales. Considerable variation was observed among genera, or even species within some genera, that contained this gene. Partial sequences of lcf were obtained for the genera Ceratocorys, Ceratium, Fragilidium, and Protoperidinium as well as from previously untested species or gene regions of Alexandrium and Gonyaulax. The sequences revealed high variation among gene copies that obscured the boundaries between species or even genera, some of which could be explained by the presence of two genetic variants within the same species of Alexandrium. Highly divergent sequences within Alexandrium and Ceratium show a more diverse composition of lcf than previously known. 相似文献
11.
Pio Colepicolo Till Roenneberg David Morse Walter R. Taylor J. Woodland Hastings 《Journal of phycology》1993,29(2):173-179
In the unicellular algae Pyrocystis lunula Schütt and Gonyaulax polyedra Stein, bioluminescence and its circadian regulation are similar in several respects, but there are also several important differences. As in G. polyedra, P. lunula emits light both as bright flashes and as a low intensity glow. At 20° C, the individual flashes are considerably brighter than in G. polyedra, and their durations are typically less than 500 ms. Both species show a circadian rhythm in the frequency of spontaneous flashes, which peaks in the night-phase under light–dark cycles and continues in both continuous light and dark. However, compared to G. polyedra, the circadian system in P. lunula is more sensitive to light: 10 min exposures (500 μmol · m–2· s–1 white light) can shift the phase of the rhythm by more than 8 h, and rhythmicity is completely suppressed at an irradiance above 20 μmol · m–2· s–1, where the G. polyedra rhythym persists for weeks. Like G. polyedra, period length increases with increasing irradiance of continuous red light but decreases with increasing intensity of continuous blue light. The glow in P. lunula differs markedly from that in G. polyedra in that it occurs at about the same intensity at all times during the circadian cycle; thus, it is not under circadian control but may fluctuate 5–10-fold in intensity within a time frame of seconds. This suggests that the glow may differ in its physiological basis in the two organisms. The results also indicate that the circadian regulation of luciferase activity differs in the two species. In G. polyedra, the organelle responsible for bioluminescence and luciferase is lost and then reformed on a daily basis; in P. lunula, the luciferase is conserved and localized elsewhere during the nonbioluminescent phase of the cycle. 相似文献
12.
Robert J. Schmidt Van D. Gooch Alfred R. Loeblich J. Woodland Hastings 《Journal of phycology》1978,14(1):5-9
Three of ten cultures of Gonyaulax excavata (Braarud) Balech isolated from the 1972 New England red tide are nonluminescent, Biochemical components of dinoflagellate bioluminescence were not detected in the extracts from these three isolates. Cells of the nonluminescent cultures were identical to those of luminescent cultures as compared by light microscopy, major body plate tabulation, cell size and growth. Both luminescent and nonluminescent cells were toxic as determined by using the mouse bioassay for paralytic shellfish poisoning. All the 122 clones made from one of the luminescent isolates were luminescent suggesting this feature is a stable trait. We conclude that these isolates represent luminescent and luminescent strains of G. excavata. This is the first intraspecific investigation of in vitro bioluminescent components between nonluminescent and luminescent strains of a dinoflagellate. 相似文献
13.
This study demonstrates, for the first time, that the presence of suspended solids in waste‐activated sludge interferes with adenosine triphosphate (ATP) bioluminescence tests. The sludge subject to acid/alkaline treatment represented the test sample. Without consideration of the effect of solid concentrations, one would erroneously estimate the density levels of heterotrophic bacteria in the sludge using ATP data. A light blockage model was proposed to evaluate the luminescence reading without the interference of suspended solids. © 2001 John Wiley & Sons, Inc. Biotechnol Bioeng 75: 469–474, 2001. 相似文献
14.
15.
The green fluorescent protein (GFP) is a bioluminescent protein that can be expressed and easily detected as a fully fluorescent protein in both bacterial and eukaryotic cells. These properties, along with its ability to withstand exposure to denaturants, organic solvents, high temperature and a wide pH range, make GFP an ideal educational tool. To that end, two GFP-based laboratory modules are described that can be used to teach recombinant DNA and protein purification techniques to high school and undergraduate college students. Journal of Industrial Microbiology & Biotechnology (2000) 24, 323–326. Received 02 April 1999/ Accepted in revised form 20 November 1999 相似文献
16.
We investigated the hypothesis that bioluminescence in firefly larvae (Coleoptera: Lampyridae) functions as an aposematic
display. In two experiments, we confirmed the distastefulness of firefly larvae, and tested the hypothesis that a naive, nocturnal
predator can learn to use light signals as aposematic cues for avoiding distasteful prey. Larvae were rejected as acceptable
prey by 100% of the house mice (Mus musculus) tested. Mice learned to avoid bitter food associated with light cues significantly faster (P=0.003) than mice presented with food lacking light cues. We conclude that luminescent glowing in firefly larvae meets the
requirements of an aposematic signal. 相似文献
17.
The bioluminescence of the luminous mushroom, Lampteromyces japonicus, was studied by using the mushroom gills and also the luminous mycelia, the latter being cultured from the isolated spores and grown in a potato sucrose medium. The luminescence intensity of the mushroom gills and the cultured mycelia was measured in an aqueous suspension under various conditions. The original intensity was enhanced by exposing the luminous cells to oxygen for several hours or to acids or bases for a short period. This enhancement enabled measurement of their bioluminescence spectra which were identical to the fluorescence spectrum of riboflavin, having a maximum at 524 nm. The green fluorescent substance was extracted with cold water from the mushroom and it was identified as riboflavin by spectroscopic and chromatographic analyses. Riboflavin was concluded to be the light emitter of this mushroom. 相似文献
18.
Previous studies of the luminescence system of Siphamia versicolor (Perciformes: Apogonidae) identified a ventral light organ, reflector, lens, duct, and a ventral diffuser extending from the throat to the caudal peduncle. The control and function of luminescence in this and other species of Siphamia, however, have not been defined. Morphological examination of fresh and preserved specimens identified additional components of the luminescence system involved in control and ventral emission of luminescence, including a retractable shutter over the ventral face of the light organ, contiguity of the ventral diffuser from the caudal peduncle to near the chin, and transparency of the bones and other tissues of the lower jaw. The shutter halves retract laterally, allowing the ventral release of light, and relax medially, blocking ventral light emission; topical application of norepinephrine to the exposed light organ resulted in retraction of the shutter halves, which suggests that operation of the shutter is under neuromuscular control. The extension of the diffuser to near the chin and transparency of the lower jaw allow a uniform emission of luminescence over the entire ventrum of the fish. The live aquarium‐held fish were found to readily and consistently display ventral luminescence. At twilight, the fish left the protective association with their longspine sea urchin, Diadema setosum, and began to emit ventral luminescence and to feed on zooplankton. Ventral luminescence illuminated a zone below and around the fish, which typically swam close to the substrate. Shortly after complete darkness, the fish stopped feeding and emitting luminescence. These observations suggest that S. versicolor uses ventral luminescence to attract and feed on zooplankton from the reef benthos at twilight. Ventral luminescence may allow S. versicolor to exploit for feeding the gap at twilight in the presence of potential predators as the reef transitions from diurnally active to nocturnally active organisms. J. Morphol., 2011. © 2011 Wiley‐Liss, Inc 相似文献
19.
Alan J. A. Stewart 《Insect Conservation and Diversity》2021,14(2):163-166
- The widespread adoption of artificial lighting at night (ALAN) presents a growing threat to biodiversity in general and nocturnally active insects in particular. ALAN may be contributing to widely reported declines in insect populations but supporting evidence is sparse. Recent advances in external lighting technology, particularly the increasing adoption of broad spectrum ‘white’ LEDs, suggest that impacts of ALAN on natural systems are likely to increase.
- This special issue of Insect Conservation and Diversity presents some of the recent research addressing the impacts of ALAN on insects and their conservation. The papers cover (i) reviews of existing literature, (ii) results from experimental studies of impacts of ALAN on insects, from individual species to communities, (iii) priorities for future research, and (iv) best practice recommendations for designing future experimentation.
- Collectively, the papers illustrate a vibrant and expanding field of enquiry. In addition to further studies of effects at the individual insect level, future research priorities will need to address how ALAN affects long-term population dynamics, the composition of insect communities and ecosystem services.
- A major challenge will be to devise novel ways to minimise the adverse effects of ALAN which can be used to inform conservation interventions. Various mitigation strategies are available, including modification of the spectral composition of lighting, dimming, shielding and controlling illumination using timers and motion sensors, but require customisation for particular species and situations.