Biomass of thraustochytrid protoctists in coastal water

Kimura, Hiroyuki; Fukuba, Tatsuhiro; Naganuma, Takeshi

doi:10.3354/meps189027

Cited by 87 publications

(99 citation statements)

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“…The band pattern of SssRNAV resembles that of DCV belonging to the family Dicistroviridae, which has three major capsid proteins (31,30, and 28 kDa) and one minor capsid protein (8.5 kDa) (25,27). In addition, considering that capsid proteins of DCV are processed out of a precursor protein (100 kDa) (31,38), the functions of the 80-kDa protein of SssRNAV are also of interest.…”

Section: Resultsmentioning

confidence: 99%

“…The wide distribution and high abundance of these organisms indicate their ecological importance as decomposers (39,52). In addition, thraustochytrids are known to produce large amounts of polyunsaturated fatty acids (PUFA), such as docosahexaenoic acid and docosapentaenoic acid (44), which are considered important food resources for higher organisms in marine systems (30,34,50). Furthermore, some species of thraustochytrids are known to be pathogens of mollusks, such as octopuses and bivalves (1,46,49).…”

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confidence: 99%

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Isolation and Characterization of a Novel Single-Stranded RNA Virus Infectious to a Marine Fungoid Protist, Schizochytrium sp. (Thraustochytriaceae, Labyrinthulea)

Takao

Nagasaki

Mise

et al. 2005

Appl Environ Microbiol

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Thraustochytrids are cosmopolitan osmoheterotrophic microorganisms that play important roles as decomposers, producers of polyunsaturated fatty acids, and pathogens of mollusks, especially in coastal ecosystems. SssRNAV, a novel single-stranded RNA (ssRNA) virus infecting the marine fungoid protist Schizochytrium sp. (Labyrinthulea, Thraustochytriaceae) was isolated from the coastal water of Kobe Harbor, Japan, in July 2000, and its basic characteristics were examined. The virus particle is icosahedral, lacks a tail, and is ca. 25 nm in diameter. SssRNAV formed crystalline arrays and random assemblies within the cytoplasm of host cells, and it was also concentrated along the intracellular membrane structures. By means of one-step growth experiments, the lytic cycle and the burst size were estimated to be <8 h and 5.8 ؋ 10 3 to 6.4 ؋ 10 4 infectious units per host cell, respectively. SssRNAV had a single molecule of ssRNA that was approximately 10.2 kb long, three major proteins (37, 34, and 32 kDa), and two minor proteins (80 and 18 kDa). Although SssRNAV was considered to have some similarities with invertebrate viruses belonging to the family Dicistroviridae based on its partial nucleotide sequence, further genomic analysis is required to determine the detailed classification and nomenclature of SssRNAV. Our results indicate that viral infection is one of the significant factors controlling the dynamics of thraustochytrids and provide new insights into understanding the ecology of these organisms.

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Section: Resultsmentioning

confidence: 99%

mentioning

confidence: 99%

Isolation and Characterization of a Novel Single-Stranded RNA Virus Infectious to a Marine Fungoid Protist, Schizochytrium sp. (Thraustochytriaceae, Labyrinthulea)

Takao

Nagasaki

Mise

et al. 2005

Appl Environ Microbiol

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“…Kimura et al (1999) and Raghukumar et al (2001) obtained a value of 20.6 pg C per thraustochytrid cell with an average cell diameter of 5 μm. These studies (Kimura et al 1999, Raghukumar et al 2001, Bongiorni et al 2005a, Naganuma et al 2006, Damare and Raghukumar 2008 have provided much insight into the biomass of these organisms. Thus, it is now clear that Labyrinthulomycetes often attain substantial numbers in the water column (Table 3) and their biomass as organic carbon is often considerable, occasionally even exceeding bacterial biomass (Fig.…”

Section: Biomass and Productivity Of Labyrinthulomycetesmentioning

confidence: 99%

“…Hence, the involvement of Labyrinthulomycetes in the microbial loop may have far reaching implications in the food web (Naganuma et al 1998, Kimura et al 1999. However, few studies have examined the role of Labyrinthulomycetes as food for microzooplankton.…”

Section: The Role Of Labyrinthulomycetes In the Marine Ecosystemmentioning

confidence: 99%

Increasing evidence for the important role of Labyrinthulomycetes in marine ecosystems

Raghukumar¹,

Damare

2011

Botanica Marina

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This review summarizes increasing evidence for the role of Labyrithulomycetes in marine ecosystems gathered over the last six decades. It focuses on their diversity, habitats, biomass, productivity and overall role in food webs and remineralization. Earlier studies contributed enormously to the cultured diversity of Labyrinthulomycetes. In recent years, their uncultured diversity has been demonstrated in exotic environments like the deep sea and anoxic waters. These findings emphasize the need for novel culture methods to grow these organisms. Many species seem to be substrate-specific in their occurrence. Their commensalistic or mutualistic occurrence in marine invertebrates deserves attention.The biomass of Labyrinthulomycetes in the water column may often match or even exceed that of bacteria, although such occurrences seem to be seasonal. There is a major knowledge gap on their productivity and turnover in the water column. The high biomass and production of several degradative enzymes indicate their importance as remineralizers in the ocean. However, the mechanisms by which they overcome bacterial competition are not clear. It is likely that they occupy special niches, such as marine aggregates. One role of the Labyrinthulomycetes suggested in this review, based on preliminary experiments, is that of 'left-over scavenging', following bacterial growth.

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“…A typical milliliter of seawater contains from 10 3 to 10 4 fungal cells (Kubanek et al, 2003). Coastal waters may contain much larger mycoplankton populations because these waters contain significant fungal and nutritional inputs from terrestrial sources (Kimura et al, 1999Vogel et al, 2007). However, mycoplankton diversity in coastal oceans remains largely uncharacterized.…”

Section: Introductionmentioning

confidence: 99%

Molecular characterization of the spatial diversity and novel lineages of mycoplankton in Hawaiian coastal waters

2009

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Microbial community diversity and composition have critical biogeochemical roles in the functioning of marine ecosystems. Large populations of planktonic fungi exist in coastal ocean waters, yet their diversity and role in carbon and nutrient cycling remain largely unknown. Lack of information on critical functional microbial groups limits our understanding of their ecological roles in coastal oceans and hence our understanding of its functioning in the ocean's carbon and nutrient cycles. To address this gap, this study applied the molecular approach denaturing gradient gel electrophoresis (DGGE) coupled with clone library construction to investigate mycoplankton communities in Hawaiian coastal waters. Mycoplankton communities displayed distinct lateral and vertical variations in diversity and composition. Compared with the open ocean, surface (o100 m) near-shore waters had the greatest diversity and species richness of mycoplankton, whereas no differences were found among stations at depths below 150 m. Vertical diversity profiles in the coastal waters suggested that diversity and species richness were positively correlated to phytoplankton biomass in the coastal waters, but not in offshore waters. A total of 46 species were identified and belonging to two phyla Basidiomycota and Ascomycota, with the basidiomycetes as the dominant group (n ¼ 42). The majority (n ¼ 27) of the basidiomycetes are novel phylotypes showing less than 98% identity in the 18S rRNA gene with any sequence in GenBank. This study provides insight into mycoplankton ecology and is the first molecular analysis of planktonic fungi in the oceans. The ISME Journal (

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Biomass of thraustochytrid protoctists in coastal water

Cited by 87 publications

References 10 publications

Isolation and Characterization of a Novel Single-Stranded RNA Virus Infectious to a Marine Fungoid Protist, Schizochytrium sp. (Thraustochytriaceae, Labyrinthulea)

Isolation and Characterization of a Novel Single-Stranded RNA Virus Infectious to a Marine Fungoid Protist, Schizochytrium sp. (Thraustochytriaceae, Labyrinthulea)

Increasing evidence for the important role of Labyrinthulomycetes in marine ecosystems

Molecular characterization of the spatial diversity and novel lineages of mycoplankton in Hawaiian coastal waters

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