The affiliation of Hexasterias problematica and Halodinium verrucatum sp. nov. to ciliate cysts based on molecular phylogeny and cyst wall composition

Gurdebeke, Pieter; Mertens, Kenneth Neil; Takano, Yoshihito; Yamaguchi, Aika; Bogus, Kara; Dunthorn, Micah; Matsuoka, Kazumi; Vrielinck, Henk; Louwye, Stephen

doi:10.1016/j.ejop.2018.09.002

Cited by 22 publications

(20 citation statements)

References 81 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Concentrations of organic linings of foraminifera are high in the inner part of the gulf, reaching 2,018 g -1 , with an overall average of 748 linings g -1 . Halodinium sp., described originally as an acritarch (Bujak, 1984) and now confirmed as the resting cyst of an estuarine ciliate (Gurdebeke et al, 2018), are more abundant in the central and southern SJG, with a maximum value of 102 cells g -1 at site BV50, and low concentrations in the northern part of the gulf and offshore. This taxon suggests freshwater inputs to in our study area.…”

Section: Resultsmentioning

confidence: 89%

Distribution of Modern Dinoflagellate Cyst Assemblages in Surface Sediments of San Jorge Gulf (Patagonia, Argentina)

Faye¹,

Rochon²,

St‐Onge³

2018

Oceanog

View full text Add to dashboard Cite

INTRODUCTION The Southwest Atlantic is an area of high primary productivity, where upwellings and oceanic fronts control the intensity of organic production (Gregg et al., 2005; Rivas et al., 2006). Along the Argentinian coasts, dinoflagellates and diatoms dominate the primary production (e.g., Lutz and Carreto, 1991; Segura et al., 2013; Krock et al., 2015). These microorganisms represent the bottom link in the food web and are essential for marine ecosystems. Dinoflagellates are unicellular biflagellate organisms that thrive in both freshwater and marine environments. They display a wide range of morphologies, live in a variety of habitats (Evitt, 1985; Taylor et al., 2008), and are found at all latitudes, though they are particularly abundant in coastal waters (Zonneveld et al., 2013). Most dinoflagellates are autotrophic and/or mixotrophic (50%), but some are either heterotrophic, parasitic, or ABSTRACT. The presence of upwelling systems and oceanic fronts makes the Southwest Atlantic Ocean a region of high primary productivity. These same conditions are present in San Jorge Gulf (SJG) along the southern Argentinian coast, where dinoflagellates and diatoms dominate primary production. The distribution of these microorganisms, including the cysts produced by some dinoflagellates during their life cycles, is controlled in marine environments by oceanographic parameters that include salinity, surface water temperature, ice cover duration, and productivity. The objective of this study is to document the modern distribution of dinoflagellate cyst assemblages in surface sediments so that the environmental preferences of each taxon can be inferred and used to reconstruct paleoenvironmental conditions. The dinoflagellate cyst (dinocyst) assemblages of 52 surface samples collected in 2014 aboard R/V Coriolis II in the SJG were described and compared to surface oceanographic conditions and grain size data. The results indicate dinocyst concentrations vary between 64 cysts g-1 and 45,848 cysts g-1 dry sediment, with Spiniferites ramosus and Operculodinium centrocarpum the dominant species, accompanied by Spiniferites mirabilis, Dubridinium sp., cysts of Polykrikos kofoidii, and cysts of Brigantedinium simplex, Brigantedinium auranteum, and Brigantedinium spp. We have defined two spatial domains based on the distribution of dinocysts in and near the SJG: northern/southern-central gulf and offshore domains. We found an increase in dinocyst concentrations along a north-south gradient in the SJG and minimum concentrations at offshore sites. In addition, multivariate analyses reveal the relationships among the relative abundances of dinocysts, fine grain size data (<63 μm; silts and clays), and primary productivity, as well as offshore upwelling, which appear to control most of the distribution of dinocysts.

show abstract

Section: Resultsmentioning

confidence: 89%

Distribution of Modern Dinoflagellate Cyst Assemblages in Surface Sediments of San Jorge Gulf (Patagonia, Argentina)

Faye¹,

Rochon²,

St‐Onge³

2018

Oceanog

View full text Add to dashboard Cite

show abstract

“…Most cysts are spherical ( Mulisch and Hausmann, 1989 ; Figures 2 , 3 ) or ellipsoidal ( Foissner et al, 2002 ), although flask-shape ( Kim and Taniguchi, 1995 ) or disk-shaped ( Gurdebeke et al, 2018 ) cysts have also been observed in several species. The size of cysts ranges from 15 μm in Pseudocohnilembus pusillus ( Olendzenski, 1999 ) to 225 μm in Blepharisma japonicum ( Giese, 1973 ).…”

Section: Structure Of Cystsmentioning

confidence: 99%

How Ciliated Protists Survive by Cysts: Some Key Points During Encystment and Excystment

Wang

Zhang

et al. 2022

Front. Microbiol.

View full text Add to dashboard Cite

Forming cysts is a common and important bionomic strategy for microorganisms to persist in harsh environments. In ciliated protists, many species have been reported to form cysts when facing unfavorable conditions. Despite traditional studies on the morphological features of cysts and the chemical composition of cyst wall, recent research has focused more on the molecular mechanisms of encystment. The present work reviews studies on developmental features and molecular information of resting cysts in ciliates, and pays more attention to the following questions: what are the inducing factors of encystment and excystment? How does the cell change morphologically during these dynamic processes? And what molecular mechanisms underlie those changes? We also present and summarize the characteristics of cysts from diverse ciliate lineages in a phylogenetic framework, aiming to provide new perspectives for studies on adaptive evolution of unicellular eukaryotes.

show abstract

“…Phylogenetic analyses of SSU rDNA sequences revealed that all investigated strains of Urotricha formed a highly supported monophyletic group together with Plagiocampa sp. (KY980324; Zhang et al, 2014) and Halodinium verrucatum (LC424401; Gurdebeke et al, 2018), which is placed in a distinct clade. Hence, the identification of the latter two sequences is incorrect or the genus Urotricha is not monophyletic.…”

Section: Molecular Phylogeny Of the Genus Urotrichamentioning

confidence: 99%

“…In the SSU rDNA tree of the prostomatids, two Urotricha-related sequences differ morphologically, i.e., Plagiocampa sp. (KY980324; Zhang et al, 2014) and H. verrucatum (LC424401;Gurdebeke et al, 2018). They probably represent misidentifications or crosscontaminations, especially as both the phylogenetic placement and the signatures of the V4 and the V9 gene regions indicate that they are urotrichs (Figures 6, 9).…”

Section: Molecular Markers and Morphology -Indispensable Requirements...mentioning

confidence: 99%

Molecular Data Reveal a Cryptic Diversity in the Genus Urotricha (Alveolata, Ciliophora, Prostomatida), a Key Player in Freshwater Lakes, With Remarks on Morphology, Food Preferences, and Distribution

et al. 2022

View full text Add to dashboard Cite

Species of the ciliate genus Urotricha are key players in freshwater plankton communities. In the pelagial of lakes, about 20 urotrich species occur throughout an annual cycle, some of which play a pivotal role in aquatic food webs. For example, during the phytoplankton spring bloom, they consume a remarkable proportion of the algal production. In ecological studies, urotrich ciliates are usually merely identified to genus rank and grouped into size classes. This is unsatisfying considering the distinct autecological properties of individual species and their specific spatial and temporal distribution patterns. As a basis for future research, we characterized in detail four common urotrich morphotypes, i.e., specimens identified as U. furcata and tentatively as U. agilis, U. pseudofurcata, and U. castalia, using state-of-the-art methods. We used an integrative polyphasic approach, in which morphological studies (in vivo observation, silver staining methods, scanning electron microscopy) were linked with a molecular approach exploiting four different gene fragments as taxonomic DNA barcodes with different resolution potential (SSU rDNA, ITS-1, ITS-2, hypervariable V4 and V9 regions of the SSU rDNA). We shed light on the diversity of urotrich ciliates as well as on their global distribution patterns, and annual cycles. Additionally, we coupled individual species occurrences and environmental parameters, and subsequently modeled the distribution and occurrence, using logistic regressions. Furthermore, for one strain putatively identified as U. castalia, we ascertained the optimal cultivation media and food preferences. Thereby, our comprehensive view on these important freshwater ciliates that frequently occur in environmental high throughput sequencing datasets worldwide will allow future studies to better exploit protistan plankton data from lakes.

show abstract

The affiliation of Hexasterias problematica and Halodinium verrucatum sp. nov. to ciliate cysts based on molecular phylogeny and cyst wall composition

Cited by 22 publications

References 81 publications

Distribution of Modern Dinoflagellate Cyst Assemblages in Surface Sediments of San Jorge Gulf (Patagonia, Argentina)

Distribution of Modern Dinoflagellate Cyst Assemblages in Surface Sediments of San Jorge Gulf (Patagonia, Argentina)

How Ciliated Protists Survive by Cysts: Some Key Points During Encystment and Excystment

Molecular Data Reveal a Cryptic Diversity in the Genus Urotricha (Alveolata, Ciliophora, Prostomatida), a Key Player in Freshwater Lakes, With Remarks on Morphology, Food Preferences, and Distribution

Contact Info

Product

Resources

About