Abstract
Two thraustochytrids, Thraustochytrium striatum Schneider and Schizochytrium mangrovei Raghukumar, isolated in 1989 in axenic cultures using pine pollen in seawater from mangroves in Goa, India, were observed in continuous-flow chambers. When grown in the presence of bacteria, both species produced amoebae, which moved using pseudopodia and phagocytosed bacterial cells. Several amoebae were produced in ‘sporangia’, or isolated vegetative cells transformed directly into amoebae. These findings were confirmed with several single-cell isolations of the protists. The demonstration of phagotrophic amoebae in these organisms suggests a dual role for thraustochytrids in nature, namely a fungus-like breakdown of complex organic molecules as well as bacterivory. This phenomenon also places the thraustochytrics in a unique relationship with many other protistan groups.
Similar content being viewed by others
Literature cited
Bahnweg, G. (1979a). Studies on the physiology of Thraustochytriales. I. Growth requirements and nitrogen nutrition of Thraustochytrium spp., Schizochytrium sp., Japonochytrium sp., Ulkenia spp. and Labyrinthuloides spp. Veröff. Inst. Meeresforsch. Bremerh. 17: 245–268
Bahnweg, G. (1979b). Studies on the physiology of Thraustochytriales. II. Carbon nutrition of Thraustochytrium spp., Schizochytrium sp., Japonochytrium sp., Ulkenia spp. and Labyrinthuloides spp. Veröff. Inst. Meeresforsch. Bremerh. 17: 269–273
Bahnweg, G., Sparrow, F. K. Jr. (1974). Four new species of Thraustochytrium from Antarctic regions, with notes on the distribution of zoosporic fungi in the Antarctic marine ecosystems. Am. J. Bot. 61: 754–766
Bird, D. F., Kalff, J. (1986). Bacterial grazing by planktonic algae. Science, N.Y. 231: 493–495
Bird, D. F., Kalff, J. (1989). Phagotrophic sustenance of a metalimnetic phytoplankton peak. Limnol. Oceanogr. 34: 155–162
Caron, D. A. (1987). Grazing of attached bacteria by heterotrophic microflagellates. Microb. Ecol. 13: 203–218
Chamberlain, A. H. L., Moss, S. T. (1988). The thraustochytrids: a protist group with mixed affinities. Biosystems (Amsterdam) 21: 341–349
Coleman, N. K., Vestal, J. R. (1987). An epifluorescent microscope study of enzymatic hydrolysis of fluorescein diacetate associated with the ectoplasmic net elements of the protist Thraustochytrium striatum. Can. J. Microbiol. 33: 841–843
Fenchel, T., Harrison, P. (1976). The significance of bacterial grazing and mineral cycling for the decomposition of particulate detritus. In: Anderson, J. M., MacFadyen, A. (eds.) The role of terrestrial and aquatic organisms in decomposition processes. Blackwell Scientific Publications, Oxford, p. 285–299
Florin-Christensen, J., Florin-Christensen, M., Tiedtke, A., Rasmussen, L. (1990). The role of secreted acid hydrolases in the utilization of complex nutrients by Tetrahymena. Microb. Ecol. 19: 311–316
Gaertner, A. (1966). Vorkommen, Physiologie und Verteilung “mariner niederer Pilze” (Aquatic Phycomycetes). Veröff. Inst. Meeresforsch. Bremerh. (Suppl.) 2: 221–236
Gaertner, A. (1967). Niederer mit Pollen köderbare Pilze in der südlichen Nordsee. Veröff. Inst. Meeresforsch. Bremerh. 10: 159–165
Gaertner, A. (1968). Eine Methode des quantitativen Nachweises niederer mit Pollen köderbarer Pilze im Meereswasser und im Sediment. Veröff. Inst. Meeresforsch. Bremerh. 3: 75–92
Gaertner, A. (1977). Revision of Thraustochytriaceae (lower marine fungi) I. Ulkenia nov. gen., with description of three new species. Veröff. Inst. Meeresforsch. Bremerh. 16: 139–157
Gaertner, A. (1982). Lower marine fungi from the Northwest African upwelling areas and from the Atlantic off Portugal. “Meteor” ForschErgebn. (Reihe D) 34: 9–30
Kazama, F. Y., Zachary, A. L., Schornstein, K. L. (1975). Observations on Thraustochytrium sp. development and behaviour in culture. Can. J. Bot. 53: 360–374
Moss, S. T. (1985). An ultrastructural study of taxonomically significant characters of the Thraustochytriales and the Labyrinthulales. J. Linn. Soc. (Bot.) 91: 329–357
Moss, S. T. (1986). Biology and phylogeny of the Labyrinthulales and Thraustochytriales. In: Moss, S. T. (ed.) The biology of marine fungi. Cambridge University Press, Cambridge, p. 105–129
Olive, L. S. (1975). The mycetozoans. Academic Press, New York
Pandian, T. J. (1975). Mechanisms of heterotrophy. In: Kinne, O. (ed.) Marine ecology, Vol. II, Physiological mechanisms, Part 1. John Wiley & Sons, London, p. 61–249
Patterson, D. J., Fenchel, T. (1990). Massisteria marina Larsen & Patterson, a widespread and abundant bacterivorous protist associated with marine detritus. Mar. Ecol. Prog. Ser. 62: 11–19
Perkins, F. O. (1973). Observations on thraustochytriaceous (Phycomycetes) and labyrinthulid (Rhizopodea) ectoplasmic nets on natural and artificial substrates — an electron microscope study. Can. J. Bot. 51: 485–491
Raghukumar, S. (1980). Morphology and taxonomy of the protist Gymnophrydium marinum Dangeard from the North Sea. Botanica mar. 23: 353–360
Raghukumar, S. (1987a). A device for continuous microscopic observations of aquatic microorganisms. Indian J. mar. Sci. 16: 132–133
Raghukumar, S. (1987b). Occurrence of the thraustochytrid Corallochytrium limacisporum gen. et sp. nov. in the coral reef lagoons of the Lakshadweep islands in the Arabian Sea. Botanica mar. 30: 83–89
Raghukumar, S. (1990). Speculations on niches occupied by fungi in the sea with relation to bacteria. Proc. Indian Acad. Sci. 100: 129–138
Raghukumar, S., Gaertner, A. (1980). Ecology of the thraustochytrids (lower marine fungi) in the Fladen Ground and other parts of the North Sea. II. Veröff. Inst. Meeresforsch. Bremerh. 20: 289–308
Raghukumar, S., Raghukumar, Chandralata, Rajendran, A. (1991). Abundance of thraustochytrid fungi in the Arabian Sea. Estuar. cstl Shelf Sci. 31: 351–358
Sanders, R. W., Porter, K. G., Caron, D. A. (1990). Relationship between phototrophy and phagotrophy in the mixotrophic chrysophyte Poterioochromonas malhamensis. Microb. Ecol. 19: 97–109
Schmoller, H. von (1966). Beitrag zur Kenntnis der Labyrinthulen-Entwicklung. Arch. Protistenk. 109: 226–244
Schneider, J. (1968). Über niedere Phycomyceten der westlichen Ostsee. Veröff. Inst. Meeresforsch. Bremerh. (Suppl.) 3: 93–102
Author information
Authors and Affiliations
Additional information
Communicated by O. Kinne, Oldendorf/Luhe
Rights and permissions
About this article
Cite this article
Raghukumar, S. Bacterivory: a novel dual role for thraustochytrids in the sea. Marine Biology 113, 165–169 (1992). https://doi.org/10.1007/BF00367650
Accepted:
Issue Date:
DOI: https://doi.org/10.1007/BF00367650