Chloroplast-Retention in Ciliated Protozoa

Stoecker, Diane K.

doi:10.1007/978-1-4615-2818-0_2

Cited by 4 publications

(3 citation statements)

References 29 publications

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“…It is also, nevertheless, not just specific to organelles since the non-living storage product of E. proxima, paramylon, is enrobed and retained as well. Sequestration of organelles in P. ovum is not due to the resistance to digestion of cellular components within a single food vacuole as has been postulated for the oligotrichous ciliates examined to date [29]. The end result is the same, however, with the surrounding host membrane probably affording protection from digestion or recognition as a foreign body by lytic enzymes of the ciliate.…”

Section: Discussionmentioning

confidence: 68%

“…In the plastidic-ciliatelalgal relationships thus far examined, the prey species of unicellular algae either utilized in culture experiments or identified from their in-situ morphology are cells that are relatively small compared to their predator and contain only one chloroplast [29]. The cultures used include Zsochrysis galbana, Pyramimonas sp., and Pyrenomonas salina [29]. The predatodprey association that we have examined in the Pettaquamscutt River estuary is very unique.…”

Section: Discussionmentioning

confidence: 99%

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Ultrastructure and Ecology of Perispira ovum (Ciliophora: Litostomatea): An Aerobic, Planktonic Ciliate that Sequesters the Chloroplasts, Mitochondria, and Paramylon of Euglena proxima in a Micro‐oxic Habitat

Johnson

Donaghay

Small

et al. 1995

J Eukaryotic Microbiology

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ABSTRACT. High resolution sampling of the stratified water column in a fjord‐like ecosystem revealed a green‐pigmented planktonic ciliate that was found to be a ravenous predator of Euglena proxima. The vertical distributions of both predator and prey were coincident, and maximum populations occurred across the transition from oxic to anoxic water. This ciliate was identified as Perispira ovum (family Spathidiidae; Order Haptorida). P. ovum was observed by transmission electron microscopy to retain not only the chloroplasts, but also the mitochondria and paramylon reserve of its algal prey. A mechanism of sequestration of algal organelles is demonstrated for the first time. This mechanism includes: recognition, capture, and ingestion of prey; rupture and release of algal cell contents; and enrobing of individual organelles and paramylon by the host vacuolar membrane. The structural integrity, peripheral location, and association with host endoplasmic reticulum suggests the sequestered organelles may be functional within P. ovum. The occurrence and high biomass of this aerobic ciliate in an oxygen‐limited environment also suggests that the sequestered chloroplasts are photosynthetically active and may provide additional substrates (such as oxygen) and metabolic capabilities that are crucial for its survival.

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Section: Discussionmentioning

confidence: 68%

Section: Discussionmentioning

confidence: 99%

Ultrastructure and Ecology of Perispira ovum (Ciliophora: Litostomatea): An Aerobic, Planktonic Ciliate that Sequesters the Chloroplasts, Mitochondria, and Paramylon of Euglena proxima in a Micro‐oxic Habitat

Johnson

Donaghay

Small

et al. 1995

J Eukaryotic Microbiology

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“…The oligotrichs are mixotrophic because they also ingest and digest algal and non‐algal prey as well as employ photosynthesis using captured chloroplasts. Chloroplasts, which do not reproduce inside the ciliate and therefore must be constantly replenished ( Stoecker & Silver, 1990), are retained from different types of algal prey and generally arranged around the cell perimeter ( Laval‐Peuto & Febvre, 1986; Stoecker, 1992). The amount of chlorophyll contained in mixotrophic oligotrichs is comparable, on a per unit volume basis, to that found in diatoms and dinoflagellates of similar size ( Fig.…”

Section: Introductionmentioning

confidence: 99%

Costs, benefits and characteristics of mixotrophy in marine oligotrichs

Dolan

Pérez

2000

Freshwater Biology

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1. Oligotrich ciliates are an important part of most marine plankton communities. Mixotrophic (chloroplast‐sequestering) oligotrichs, a common component of marine oligotrich communities, obtain fixed carbon from both photosynthesis as well as the ingestion of particulate food. Mixotrophy, in general, is often considered an adaptation permitting exploitation of food‐poor environments. We examined the hypothesis that, among oligotrichs, mixotrophs may be at a disadvantage relative to heterotrophs in food‐rich conditions in a nutrient‐enrichment experiment. We compared growth responses of mixotrophic and heterotrophic oligotrichs in natural communities from the N.W. Mediterranean Sea in microcosms with daily nutrient additions resulting in increases in nanoflagellates and Synechococcus populations. The results indicated that both mixotrophic and heterotrophic oligotrichs respond to prey increases with rapid growth (μ=1.2 d−1).  2. To examine the hypothesis that the proportion of mixotrophic to heterotrophic oligotrichs changes with the trophic status of a system, increasing with oligotrophy, we examined data from a variety of marine systems. Across systems ranging in chlorophyll concentration from about 0.1 to 40 μg L−1, oligotrich cell concentrations are correlated with chlorophyll concentrations, and mixotrophs are a consistent component of oligotrich communities, averaging about 30% of oligotrich cell numbers.  3. We discuss the costs, benefits and possible uses of mixotrophy in marine oligotrichs and suggest that mixotrophy in marine oligotrichs is not closely linked to the exploitation of food‐poor environments, but probably serves a variety of purposes.

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From Prey via Endosymbiont to Plastid: Comparative Studies in Dinoflagellates

Schnepf

1992

Origins of Plastids

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Chloroplast-Retention in Ciliated Protozoa

Cited by 4 publications

References 29 publications

Ultrastructure and Ecology of Perispira ovum (Ciliophora: Litostomatea): An Aerobic, Planktonic Ciliate that Sequesters the Chloroplasts, Mitochondria, and Paramylon of Euglena proxima in a Micro‐oxic Habitat

Ultrastructure and Ecology of Perispira ovum (Ciliophora: Litostomatea): An Aerobic, Planktonic Ciliate that Sequesters the Chloroplasts, Mitochondria, and Paramylon of Euglena proxima in a Micro‐oxic Habitat

Costs, benefits and characteristics of mixotrophy in marine oligotrichs

From Prey via Endosymbiont to Plastid: Comparative Studies in Dinoflagellates

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