Photosynthesis and Phototaxis in Ulva Lactuca Gametes

Haxo, F. T.; Clendenning, K. A.

doi:10.2307/1538559

Cited by 40 publications

(9 citation statements)

References 21 publications

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“…As seen in figure 1, the spectrum of P-460 is almost identical to the spectrum obtained by isomerizing pro-y-carotene (31), and it would therefore appear that P-460 is a naturally occurring cis-isomer of y-carotene. Haxo and Clendenning have reported large amounts of y-carotene in the gametes of the green alga, Ulva (11).…”

Section: Discussionmentioning

confidence: 99%

Carotenoids of Wild Type and Mutant Strains of the Green Aiga, Chlamydomonas reinhardi

Krinsky¹,

Levine²

1964

Plant Physiol.

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Section: Discussionmentioning

confidence: 99%

Carotenoids of Wild Type and Mutant Strains of the Green Aiga, Chlamydomonas reinhardi

Krinsky¹,

Levine²

1964

Plant Physiol.

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“…The use of swarmer chloroplasts and eyespots by these ciliates raises interesting questions about how the ciliates' behavior is connected to that of their food. For example, green macroalgae have been shown to release swarmers periodically in response to cycles of exposure/inundation (cued to temperature and/or desiccation), light, and spring/neap tidal variations (Haxo and Clendenning 1953;Christie and Notes Evans 1962;Pringle 1986). Thus, the ciliates' food supply is pulsed in response to a variety of forcings.…”

Section: Methods-cloningmentioning

confidence: 99%

“…Another interesting aspect of this interaction is how the photobehavior of the ciliates may be cued to that of their swarmer cell prey. The gamete swarmer cells of some green algae show positive phototaxis prior to syngamy and negative phototaxis (for settlement) thereafter (Haxo and Clendenning 1953). S. oculatum has been shown to shift from positive to negative phototaxis depending on tidal stage (Jonsson 1994).…”

Section: Methods-cloningmentioning

confidence: 99%

Marine planktonic ciliates that prey on macroalgae and enslave their chloroplasts

McManus

Zhang

Lin

2004

Limnology & Oceanography

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Abstract-We found two tide-pool ciliates, Strombidium oculatum and Strombidium stylifer, that ingest ulvaceous green macroalgae and retain their chloroplasts. Sequences of the form I ribulose bisphosphate carboxylase/oxygenase (rubisco) large subunit gene (rbcL1) from chloroplasts found in the ciliates cluster with the Ulvophyceae sequences on GenBank and with those of ulvaceous macroalgae from pools in which the ciliates were collected. In addition, we have cultivated S. stylifer in vitro on filtered seawater supplemented with pieces of Enteromorpha thalli that had been treated with light and temperature shock to maximize production of reproductive unicells (swarmers). An average growth rate of 1.08 Ϯ 0.07 SE [standard error] d Ϫ1 was measured when S. stylifer was grown this way. Because both ciliates and the algal swarmers contain eyespots while vegetative cells in the Ulvophyceae do not, we speculate that these reproductive cells are the source of both the chloroplasts and the pigments used in the ciliates' eyespots. This ciliate will not grow in the dark and is required to ingest fresh chloroplasts every few days, making it an obligate mixotroph. Ingestion of macroalgae by ciliates constitutes an upside-down trophic link, contrary to the usual pattern for planktonic food webs, in which production passes from very small organisms to successively larger ones. Our finding suggests that macroalgal production, heretofore believed to contribute predominantly to detrital or macroherbivore food chains, may be an important food source in the nearshore plankton and that ciliates may play an important role in this trophic pathway.

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“…Data on gamete size and speed were found for two species of isogamous green algae (Haxo & Clendenning, 1953;Racey et al, 1981;RuK !er & Nultsch, 1985), one anisogamous green alga (Togashi et al, 1997), one anisogamous aquatic fungus (Pommerville, 1978), sperm of a brown seaweed (Maier & MuK ller, 1986), and sperm of four sea urchin species (Chia et al, 1975;Gray, 1955;Levitan, 1993;Levitan et al, 1991). The rank correlation between gamete speed and volume was not signi"cant by either the Spearman or Kendall methods (StatView).…”

Section: Numerical Valuesmentioning

confidence: 99%

“…Alternatively, a collimating stimulus can be used to maintain a constant orientation (Dusenbery, 1992, p. 397;Pline & Dusenbery, 1987). The gametes of many marine algae are known to be phototactic (Haxo & Clendenning, 1953;Togashi et al, 1997), and they may be using light as a collimating stimulus, which allows them to maintain a straight path over very large distances. So failure to swim straight paths is not a problem for the model, because gametes can avoid the e!ect if necessary.…”

Section: Swimming Pathmentioning

confidence: 99%

Selection for High Gamete Encounter Rates Explains the Success of Male and Female Mating Types

Dusenbery

2000

Journal of Theoretical Biology

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Sexual reproduction occurs in many small eukaryotes by fusion of similar gametes (isogamy). In the absence of distinguishable sperm and eggs, male and female mating types are missing. However, species with distinct males and females have so prospered that almost all familiar plants and animals have these mating types. Why has sexual reproduction involving sperm and eggs been so successful? An answer is obtained by considering physical limitations on encounter rates between gametes. A biophysical model based on well-established relationships produces "tness landscapes for the evolution of gamete size and energy allocation between motility and pheromone production. These landscapes demonstrate that selection for high gamete encounter rates favors large, pheromone-producing eggs and small, motile sperm. Thus, broadcast-spawning populations with males and females can reproduce at lower population densities and survive under conditions where populations lacking males and females go extinct. It appears that physical constraints on gamete encounter rates are su$cient to explain the "rst two steps in the isogamyPanisogamyPoogamyPinternal fertilization evolutionary sequence observed in several lineages of the eukaryotes. Unlike previous models, assumptions concerning zygote "tness or decreasing speed of swimming with increasing gamete size are not required.

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Photosynthesis and Phototaxis in Ulva Lactuca Gametes

Abstract: During reproduction many multicellular algae form fertile areas which differ in color from the vegetative portions and from which are ultimately shed diversely pigmented gametes. These color differences may involve large changes in the

Cited by 40 publications

References 21 publications

Carotenoids of Wild Type and Mutant Strains of the Green Aiga, Chlamydomonas reinhardi

Carotenoids of Wild Type and Mutant Strains of the Green Aiga, Chlamydomonas reinhardi

Marine planktonic ciliates that prey on macroalgae and enslave their chloroplasts

Selection for High Gamete Encounter Rates Explains the Success of Male and Female Mating Types

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