The chemical defense ecology of marine unicellular plankton: constraints, mechanisms, and impacts

Wolfe, Gordon V.

doi:10.2307/1542526

Cited by 234 publications

(188 citation statements)

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“…Defense against predators is another possible function of some osmolytes. DMSP (Fig.·2), widespread in marine microalgae, can be broken down into a gas, DMS (dimethylsulfide), and acrylate, which may serve to repel grazers such as copepods (Wolfe, 2000;Van Alstyne and Houser, 2003). In some terrestrial plants, hydroxyprolinebetaine is accumulated in water stress; an isomer of this (trans-4-hydroxy-L-prolinebetaine) is a strong inhibitor of animal acetylcholine esterase and therefore may deter herbivores .…”

Section: Other Metabolic Roles and Compatibility Revisitedmentioning

confidence: 99%

Organic osmolytes as compatible, metabolic and counteracting cytoprotectants in high osmolarity and other stresses

Yancey

2005

Journal of Experimental Biology

1,576

1,272

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SUMMARY Organic osmolytes are small solutes used by cells of numerous water-stressed organisms and tissues to maintain cell volume. Similar compounds are accumulated by some organisms in anhydrobiotic, thermal and possibly pressure stresses. These solutes are amino acids and derivatives,polyols and sugars, methylamines, methylsulfonium compounds and urea. Except for urea, they are often called `compatible solutes', a term indicating lack of perturbing effects on cellular macromolecules and implying interchangeability. However, these features may not always exist, for three reasons. First, some of these solutes may have unique protective metabolic roles, such as acting as antioxidants (e.g. polyols, taurine, hypotaurine),providing redox balance (e.g. glycerol) and detoxifying sulfide (hypotaurine in animals at hydrothermal vents and seeps). Second, some of these solutes stabilize macromolecules and counteract perturbants in non-interchangeable ways. Methylamines [e.g. trimethylamine N-oxide (TMAO)] can enhance protein folding and ligand binding and counteract perturbations by urea (e.g. in elasmobranchs and mammalian kidney), inorganic ions, and hydrostatic pressure in deep-sea animals. Trehalose and proline in overwintering insects stabilize membranes at subzero temperatures. Trehalose in insects and yeast,and anionic polyols in microorganisms around hydrothermal vents, can protect proteins from denaturation by high temperatures. Third, stabilizing solutes appear to be used in nature only to counteract perturbants of macromolecules,perhaps because stabilization is detrimental in the absence of perturbation. Some of these solutes have applications in biotechnology, agriculture and medicine, including in vitro rescue of the misfolded protein of cystic fibrosis. However, caution is warranted if high levels cause overstabilization of proteins.

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Section: Other Metabolic Roles and Compatibility Revisitedmentioning

confidence: 99%

Organic osmolytes as compatible, metabolic and counteracting cytoprotectants in high osmolarity and other stresses

Yancey

2005

Journal of Experimental Biology

1,576

1,272

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“…E. huxleyi, like many taxa from the Haptophyceae and Dinophyceae, is a notorious bloom-forming species that produces concentrated intracellular DMSP (Wolfe, 2000). DMSP is considered to be nontoxic and serves as an excellent compatible osmolyte (Dickson and Kirst, 1987) and may additionally act as a cryoprotectant (Karsten et al, 1996).…”

Section: Microzooplankton Grazing Biomass and Abundancementioning

confidence: 99%

“…data) showed the dinoflagellates Amphidinium longum and Gymnodinium sp. readily ingest E. huxleyi with low DMSP lyase activity (Wolfe, 2000), but avoid grazing on high-lyase E. huxleyi. These prey strains were morphologically identical, with only slight variations in chemical composition (total C, N, protein, lipid, carbohydrate, mineral, and dry weight).…”

Section: Microzooplankton Grazing Biomass and Abundancementioning

confidence: 99%

“…These prey strains were morphologically identical, with only slight variations in chemical composition (total C, N, protein, lipid, carbohydrate, mineral, and dry weight). Although other unknown mechanisms may contribute to feeding selectivity, Wolfe (2000) states the only clear polymorphism that covaries with feeding selectivity is DMSP lyase activity, which most likely results in feeding deterrence by microzooplankton.…”

Section: Microzooplankton Grazing Biomass and Abundancementioning

confidence: 99%

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Phytoplankton growth, microzooplankton herbivory and community structure in the southeast Bering Sea: insight into the formation and temporal persistence of an Emiliania huxleyi bloom

Olson

Strom

2002

Deep Sea Research Part II: Topical Studies in Oceanography

143

108

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Using the seawater dilution technique, we measured phytoplankton growth and microzooplankton grazing rates within and outside of the 1999 Bering Sea coccolithophorid bloom. We found that reduced microzooplankton grazing mortality is a key component in the formation and temporal persistence of the Emiliania huxleyi bloom that continues to proliferate in the southeast Bering Sea. Total chlorophyll a (Chl a) at the study sites ranged from 0.40 to 4.45 mg C l À1 . Highest phytoplankton biomass was found within the bloom, which was a mixed assemblage of diatoms and E. huxleyi. Here, 75% of the Chl a came from cells >10 mm and was attributed primarily to the high abundance of the diatom Nitzschia spp. Nutrient-enhanced total phytoplankton growth rates averaged 0.53 d À1 across all experimental stations. Average growth rates for >10 mm and o10 mm cells were nearly equal, while microzooplankton grazing varied among stations and size fractions. Grazing on phytoplankton cells >10 mm ranged from 0.19 to 1.14 d À1 . Grazing on cells o10 mm ranged from 0.02 to 1.07 d À1 , and was significantly higher at non-bloom (avg. 0.71 d À1 ) than at bloom (avg. 0.14 d À1 ) stations. Averaged across all stations, grazing by microzooplankton accounted for 110% and 81% of phytoplankton growth for >10 and o10 mm cells, respectively. These findings contradict the paradigm that microzooplankton are constrained to diets of nanophytoplankton and strongly suggests that their grazing capability extends beyond boundaries assumed by size-based models. Dinoflagellates and oligotrich ciliates dominated the microzooplankton community. Estimates of abundance and biomass for microzooplankton >10 mm were higher than previously reported for the region, ranging from 22,000 to 227,430 cells l À1 and 18 to 164 mg C l À1 . Highest abundance and biomass occurred in the bloom and corresponded with increased abundance of the large ciliate Laboea, and the heterotrophic dinoflagellates Protoperidinium and Gyrodinium spp. Despite low grazing rates on phytoplankton o10 mm within the bloom, the abundance and biomass of small microzooplankton (o20 mm) capable of grazing E. huxleyi was relatively high at bloom stations. This body of evidence, coupled with observed high grazing rates on large phytoplankton cells, suggests the phytoplankton community composition was strongly regulated by herbivorous activity of microzooplankton. Because grazing behavior deviated from size-based model predictions and was not proportional to microzooplankton biomass, alternate mechanisms that dictate levels of grazing activity were in effect in the southeastern Bering Sea. We hypothesize that these mechanisms included morphological or chemical signaling between phytoplankton and micrograzers, which led to selective grazing pressure. r

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“…Clearly, the results reported here underscore the need to treat any ecological assumptions based studies with batch- (20,32).…”

mentioning

confidence: 76%

Regenerated extracellular NH4+ affects the motile chemosensory responses of batch-cultured Oxyrrhis marina

Martel¹

2010

Braz. J. Microbiol.

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The chemical defense ecology of marine unicellular plankton: constraints, mechanisms, and impacts

Cited by 234 publications

References 225 publications

Organic osmolytes as compatible, metabolic and counteracting cytoprotectants in high osmolarity and other stresses

Organic osmolytes as compatible, metabolic and counteracting cytoprotectants in high osmolarity and other stresses

Phytoplankton growth, microzooplankton herbivory and community structure in the southeast Bering Sea: insight into the formation and temporal persistence of an Emiliania huxleyi bloom

Regenerated extracellular NH4+ affects the motile chemosensory responses of batch-cultured Oxyrrhis marina

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