SOME FACTORS AFFECTING THE GROWTH AND DISTRIBUTION OF THE ALGAL ENDOSYMBIONTS OF<i>HYDRA VIRIDIS</i>

Pardy, R. L.

doi:10.2307/1540572

Cited by 46 publications

(22 citation statements)

References 16 publications

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“…As first suggested by Pardy (283,284), the host has the potential to regulate symbiont division so that it is closely linked to the division of its own cells. When green Hydra is fed, the diel pattern of host cell division becomes synchronized, with a peak MI of about 2% that occurs 10 to 12 h after feeding (219,266).…”

Section: Regulation Of Symbiont and Host Cell Growth And Proliferationmentioning

confidence: 99%

Cell Biology of Cnidarian-Dinoflagellate Symbiosis

Davy

Allemand

Weis

2012

Microbiol Mol Biol Rev

836

1,041

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SUMMARY The symbiosis between cnidarians (e.g., corals or sea anemones) and intracellular dinoflagellate algae of the genus Symbiodinium is of immense ecological importance. In particular, this symbiosis promotes the growth and survival of reef corals in nutrient-poor tropical waters; indeed, coral reefs could not exist without this symbiosis. However, our fundamental understanding of the cnidarian-dinoflagellate symbiosis and of its links to coral calcification remains poor. Here we review what we currently know about the cell biology of cnidarian-dinoflagellate symbiosis. In doing so, we aim to refocus attention on fundamental cellular aspects that have been somewhat neglected since the early to mid-1980s, when a more ecological approach began to dominate. We review the four major processes that we believe underlie the various phases of establishment and persistence in the cnidarian/coral-dinoflagellate symbiosis: (i) recognition and phagocytosis, (ii) regulation of host-symbiont biomass, (iii) metabolic exchange and nutrient trafficking, and (iv) calcification. Where appropriate, we draw upon examples from a range of cnidarian-alga symbioses, including the symbiosis between green Hydra and its intracellular chlorophyte symbiont, which has considerable potential to inform our understanding of the cnidarian-dinoflagellate symbiosis. Ultimately, we provide a comprehensive overview of the history of the field, its current status, and where it should be going in the future.

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Section: Regulation Of Symbiont and Host Cell Growth And Proliferationmentioning

confidence: 99%

Cell Biology of Cnidarian-Dinoflagellate Symbiosis

Davy

Allemand

Weis

2012

Microbiol Mol Biol Rev

836

1,041

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“…Population densities of syn~biotic algae in host invertebrates can be maintained for invariably long periods of time (Pardy & Muscatine 1973, Pardy 1974, Pool 1976, Muscatine & Pool 1979. A possible mechanism relating to the regulation of algal numbers is that host cells divide in 'synchrony' with the algal populations (Pardy 1974, Trench 1987).…”

Section: Introductionmentioning

confidence: 99%

“…A possible mechanism relating to the regulation of algal numbers is that host cells divide in 'synchrony' with the algal populations (Pardy 1974, Trench 1987). However, it was shown by Muscatine et al (1985) in the hermatypic coral Stylophora pistillata that the growth rate of zooxanthellae was higher than the growth rate of polyps.…”

Section: Introductionmentioning

confidence: 99%

Degradation of zooxanthellae and regulation of their density in hermatypic corals

Ea¹,

Tv²,

Leletkin³

et al. 1996

Mar. Ecol. Prog. Ser.

140

106

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ABSTRACT. This study investigated the process of zooxanthellae degradation in hermatypic corals.The number of degraded zooxanthellae in corals taken fmm rllfferent light conditions amounted to 1 to 6 % a day, which was similar to the number of dividing amxanthellae. Zooxanthellae degradation takes place only at night in the connecting sheet and tentacle but both at night and during the day in the gastroderm of the mesenteries. Zooxanthellae degradation continues for about 6 h. DNA staining with DAPI (4'6-diamidino-2-phenylindole) and light, UV and electron microscopic examinations showed that zooxanthellae under degradation lost DNA, protein of pyrenoids and lipid drops. The degraded zooxanthellae particles contained 'accumulat~on bodies', unpacked thylakoids, starch grains and a pyrenoid starch envelope. Under starvation experirnenls the number of degraded zooxanthellae in Stylophora pistillata increased in the tissue, as did thefi ~e l e a s e .It is concluded that hermatypic corals are capable of regulating their zooxanthellae p o p u l a t i a by digestion and extrusion of zooxanthellae remnants.

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“…Aposymbiotic Hydra viridis were prepared by the photobleaching method using high light intensities (Pardy, 1976a) modified by prior incubation in 10~^ M solutions of the photosynthetic inhibitor DCMU 3-(3,4 dichlorophenyl-1, 1 dimethyl urea). Pretreatment in DCMU for 8 weeks reduces the length of the high light treatment needed for photobleaching from 5 to 1-2 days.…”

Section: Experimental Organisms and Culture Mediamentioning

confidence: 99%

“…It can easily be grown in the laboratory in a defined medium (Muscatine and Lenhoff, 1965), aposymbiotic animals can be produced in large quantities by photobleaching (Pardy, 1976a), algal symbionts can be quantitatively isolated by centrifuging animal homogenates (Muscatine, 1965) and aposymbiotic animals can be reinfected with such freshly isolated algae. Additionally, the transfer of photosynthetically fixed carbon from alga to animal can be studied by a variety of methods (Muscatine and Lenhoff, 1965;Cernichiari, Muscatine and Smith, 1969).…”

Section: Introductionmentioning

confidence: 99%

The Green Hydra Symbiosis

Jolley

Smith

1978

New Phytologist

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SUMMARY The Chlorella symbiont of the ‘European’ strain of green hydra has been isolated into pure culture using conventional microbiological techniques. The symbiont grew well on Bold's basal medium, indicating that it had no fastidious nutritional requirements. It grew rapidly on liquid media, but very slowly on agar–which may explain why previous authors have failed to isolate it. The ultra structure of the cultured isolate agrees closely with published descriptions of the symbiont. The cultured isolate could also reinfect aposymbiotic hydra, and a cycle of reisolation and reinfection was followed. The cultured isolate lacked the property of maltose excretion normally shown by symbionts, but this property was restored after reinfection. A hypothesis is advanced to explain the induction of maltose synthesis and release by host animal cells.

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SOME FACTORS AFFECTING THE GROWTH AND DISTRIBUTION OF THE ALGAL ENDOSYMBIONTS OFHYDRA VIRIDIS

Abstract: Researches on the hydra-algae endosymbiosis over the last decade have produced a clearer understanding of the role of the symbiotic zoochlorellae. The works of Lenhoff (1965a, 1965b) have shown that green hydra

Cited by 46 publications

References 16 publications

Cell Biology of Cnidarian-Dinoflagellate Symbiosis

Cell Biology of Cnidarian-Dinoflagellate Symbiosis

Degradation of zooxanthellae and regulation of their density in hermatypic corals

The Green Hydra Symbiosis

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