Morphogenesis of opal teeth in calanoid copepods

Miller, Charles B.; Nelson, David M.; Weiss, C. P.; Soeldner, Al

doi:10.1007/bf02114678

Cited by 67 publications

(43 citation statements)

References 24 publications

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“…The hallmarks of diapause are a deep distribution (within 50 to 100 m of the bottom in neritic environments and below 200 to 300 m in oceanic waters (Sameoto & Herman 1990, Miller et al 1991, Dale et al 1999, Heath et al 2004), predominance of a single stage (Heath et al 2004), torpor (Hirche 1983), empty guts with reduced epithelium (Hallberg & Hirche 1980, Hirche 1983, Bonnet et al 2007), low digestive enzyme activity (Tande & Slagstad 1982, Hirche 1983, 1989), low respiration rates (Hirche 1983), and a large oil sac (Hirche 1983, Miller et al 2000. Ecdysis (molting) is delayed during diapause, and copepodids remain predominantly in the postmolt phase of jaw (mandibular gnathobase) development and have low ecdysteroid concentrations (Miller et al 1990, Johnson 2003. Other biochemical indicators associated with diapause include a low cellspecific RNA content (indicative of reduced transcriptional activity, Wagner et al 1998, and lower activity of aminoacyl-tRNA synthetases (indicative of reduced rates of protein synthesis, Yebra et al 2006).…”

Section: Resale or Republication Not Permitted Without Written Consenmentioning

confidence: 99%

Differential gene expression in diapausing and active Calanus finmarchicus (Copepoda)

Tarrant¹,

Baumgartner²,

Verslycke³

et al. 2008

Mar. Ecol. Prog. Ser.

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To survive long periods of low food availability, some calanoid copepods have a life history that includes a diapause phase during which copepodids delay development to adulthood, migrate to depth, reduce metabolism, and utilize stored lipids for nourishment. While seasonal patterns in diapause have been described, the environmental and physiological regulation of diapause has not been elucidated. We collected Calanus finmarchicus C5 copepodids from surface (0 to 39 m) and deep (157 to 201 m) waters in the Gulf of Maine, and both morphological and biochemical measurements indicated that these copepodids were from active and diapausing populations, respectively. Two complementary molecular techniques were used to compare gene expression in these 2 groups: (1) suppressive subtractive hybridization (SSH) was used to identify genes that may be differentially expressed, and (2) quantitative real-time RT-PCR was used to characterize patterns of gene expression in individual copepodids. Three genes associated with lipid synthesis, transport and storage (ELOV, FABP, RDH) were upregulated (more highly expressed) in active copepods, particularly those with small oil sacs. Expression of ferritin was greater in diapausing copepods with large oil sacs, consistent with a role of ferritin in chelating metals to protect cells from oxidative stress and/or delay development. Ecdysteroid receptor (EcR) expression was greater in diapausing copepods, highlighting the need for further investigation into endocrine regulation of copepod development. This study represents the first molecular characterization of gene expression associated with calanoid copepod diapause and provides a foundation for future investigations of the underlying mechanisms that regulate diapause. 355: 193-207, 2008 result of this build-up of lipids, copepods with this life history strategy are an extremely nutritious food source for their predators. Thus, the environmental and physiological factors that control development and, in particular, diapause, have important implications for marine ecosystem processes. KEY WORDS: Diapause · Copepod · Calanus finmarchicus · Subtractive hybridization · Gene expression · Gulf of Maine Resale or republication not permitted without written consent of the publisherMar Ecol Prog SerThe environmental signals and internal biological processes that regulate diapause in calanoid copepods are unknown, and experimental studies remain difficult because copepods do not reliably enter diapause in the laboratory. In the field, investigators have relied on a suite of behavioral, morphological, and biochemical characteristics to distinguish between diapausing and active copepodids. The hallmarks of diapause are a deep distribution (within 50 to 100 m of the bottom in neritic environments and below 200 to 300 m in oceanic waters (Sameoto & Herman 1990, Miller et al. 1991, Dale et al. 1999, Heath et al. 2004), predominance of a single stage (Heath et al. 2004), torpor (Hirche 1983), empty guts with reduced epithelium (Hallberg ...

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Section: Resale or Republication Not Permitted Without Written Consenmentioning

confidence: 99%

Differential gene expression in diapausing and active Calanus finmarchicus (Copepoda)

Tarrant¹,

Baumgartner²,

Verslycke³

et al. 2008

Mar. Ecol. Prog. Ser.

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“…This pattern is in agreement with the spring Si budget estimated by Ragueneau et al (1994), and corresponds to the increase of Si recycling from the sediment-water interface with temperature from April to June. Even though BSi reactivity in the sediment may be reduced by many processes involved during early diagenesis (see van Cappellen & Qiu 1997), suspension-feeder activity is most likely to enhance BSi dissolution kinetics by removing the organic matter coating the opal surfaces, just like zooplankton (Miller et al 1990) and bacteria (Jacobson & Andersen 1986, Bidle & Azam 1999). Thus, the timescale needed to mineralize BSi seems compatible to sustain diatom secondary blooms.…”

Section: Can Bsi Recycling Sustain Diatom Populations In Late Spring mentioning

confidence: 99%

Long-term variation of the Bay of Brest ecosystem:benthic-pelagic coupling revisited

Chauvaud¹,

Jean²,

Ragueneau³

et al. 2000

Mar. Ecol. Prog. Ser.

135

105

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Observations over the last 20 yr of the development of pelagic and benthic communities of a western European coastal ecosystem (Bay of Brest) provide complementary hypotheses to the 'silicic acid pump' hypothesis. An increase in nitrogen inputs, independent of silicic acid levels, has lowered the Si:N molar ratios during the last 20 yr in river discharges. Since 1981, maximum concentrations of chlorophyll a during the first spring bloom of the annual cycle have decreased, in contrast to the subsequent spring and summer blooms. Concomitantly, extensive spreading of an exotic gastropod Crepidula fornicata has modified the trophic structure of benthic communities by increasing suspension-feeder biomass. The following hypotheses on ecosystem functioning are made: (1) the decrease of chlorophyll biomass during the first spring bloom results from silicic acid limitation and increased suspension feeder activity, (2) benthic filtration and biodeposition activities enhance biogenic silica retention at the sediment-water interface, and (3) recycling of trapped biogenic silica maintains diatom populations by providing silicic acid in summer and reduces primary production seasonality. These hypotheses suggest that benthic organisms control the export rate of biogenic silica towards the open-water ocean and thus the specific composition of secondary phytoplankton blooms in the Bay.

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“…copepods and diatoms. Some adaptations are mechanical: copepods modify their feeding tools by increased silicification of the mouthparts (Itoh, 1970;Miller et al, 1980Miller et al, , 1990Michels et al, 2012) in response to which diatoms adjust their protective frustules, leading to an arms race that fuels evolutionary processes (Hamm and Smetacek, 2007). Some diatoms that dominate blooms experience less grazing mortality than do co-occurring species (Assmy et al, 2007;Strom et al, 2007): it was shown that in the presence of preconditioned media that contained herbivores, diatoms develop grazing-resistant morphologies such as increased cell wall silicification (Pondaven et al, 2007;Ratti et al, 2013;Zhang et al, 2017).…”

Section: Evolutionary Competition In Modern Ecosystemsmentioning

confidence: 99%

Competition between Silicifiers and Non-silicifiers in the Past and Present Ocean and Its Evolutionary Impacts

et al. 2018

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Competition is a central part of the evolutionary process, and silicification is no exception: between biomineralized and non-biomineralized organisms, between siliceous and non-siliceous biomineralizing organisms, and between different silicifying groups. Here we discuss evolutionary competition at various scales, and how this has affected biogeochemical cycles of silicon, carbon, and other nutrients. Across geological time we examine how fossils, sediments, and isotopic geochemistry can provide evidence for the emergence and expansion of silica biomineralization in the ocean, and competition between silicifying organisms for silicic acid. Metagenomic data from marine environments can be used to illustrate evolutionary competition between groups of silicifying and non-silicifying marine organisms. Modern ecosystems also provide examples of arms races between silicifiers as predators and prey, and how silicification can be used to provide a competitive advantage for obtaining resources. Through studying the molecular biology of silicifying and non-silicifying species we can relate how they have responded to the competitive interactions that are observed, and how solutions have evolved through convergent evolutionary dynamics.

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Morphogenesis of opal teeth in calanoid copepods

Cited by 67 publications

References 24 publications

Differential gene expression in diapausing and active Calanus finmarchicus (Copepoda)

Differential gene expression in diapausing and active Calanus finmarchicus (Copepoda)

Long-term variation of the Bay of Brest ecosystem:benthic-pelagic coupling revisited

Competition between Silicifiers and Non-silicifiers in the Past and Present Ocean and Its Evolutionary Impacts

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