scholarly journals The roles of age, parentage and environment on bacterial and algal endosymbiont communities in Acropora corals

2019 ◽  
Vol 28 (16) ◽  
pp. 3830-3843 ◽  
Author(s):  
Wing Yan Chan ◽  
Lesa M. Peplow ◽  
Patricia Menéndez ◽  
Ary A. Hoffmann ◽  
Madeleine J. H. Oppen
Keyword(s):  
Algal Endosymbiont

scholarly journals Symbiont population control by host-symbiont metabolic interaction in Symbiodiniaceae-cnidarian associations

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Tingting Xiang ◽  
Erik Lehnert ◽  
Robert E. Jinkerson ◽  
Sophie Clowez ◽  
Rick G. Kim ◽  
...  
Keyword(s):  
Molecular Mechanisms ◽  
Population Control ◽  
Algal Growth ◽  
Glutamate Synthase ◽  
Free Living ◽  
Nitrogen Acquisition ◽  
Symbiotic Algae ◽  
Nitrogen Ratio ◽  
Algal Endosymbiont ◽  
Exaiptasia Pallida

AbstractIn cnidarian-Symbiodiniaceae symbioses, algal endosymbiont population control within the host is needed to sustain a symbiotic relationship. However, the molecular mechanisms that underlie such population control are unclear. Here we show that a cnidarian host uses nitrogen limitation as a primary mechanism to control endosymbiont populations. Nitrogen acquisition and assimilation transcripts become elevated in symbiotic Breviolum minutum algae as they reach high-densities within the sea anemone host Exaiptasia pallida. These same transcripts increase in free-living algae deprived of nitrogen. Symbiotic algae also have an elevated carbon-to-nitrogen ratio and shift metabolism towards scavenging nitrogen from purines relative to free-living algae. Exaiptasia glutamine synthetase and glutamate synthase transcripts concomitantly increase with the algal endosymbiont population, suggesting an increased ability of the host to assimilate ammonium. These results suggest algal growth and replication in hospite is controlled by access to nitrogen, which becomes limiting for the algae as their population within the host increases.

Convolutriloba macropyga sp. nov., an uncommonly fecund acoel (Acoelomorpha) discovered in tropical aquaria

Zootaxa ◽  
2007 ◽  
Vol 1525 (1) ◽  
pp. 1-17 ◽  
Author(s):  
THOMAS SHANNON ◽  
JOHANNES G. ACHATZ
Keyword(s):  
New Species ◽  
Sexual Reproduction ◽  
Total Darkness ◽  
Temperature Range ◽  
University Of Georgia ◽  
Frontal Organ ◽  
Algal Endosymbiont ◽  
The University ◽  
A New Species ◽  
Extremes Of Temperature

A new species of Convolutriloba Hendelberg & Akesson, 1988, collected from an aquarium in Marietta, Georgia, USA, and cultured at the University of Georgia comprises exceptionally large individuals, up to 10 mm in length. Like other members of the genus, Convolutriloba macropyga sp. nov. reproduces asexually and possesses symbiotic zoochlorellae, but it also routinely reproduces sexually, laying relatively large eggs that hatch into aposymbiotic juveniles with a statocyst and frontal organ ( which are absent in the adults). C. macropyga has a narrow tolerance for extremes of temperature and salinity: it cannot survive outside of a temperature range of 18–28 degrees C and suffers 50% lethality at salinity as low as 24 ppt and as high as 44 ppt. It cannot survive total darkness for longer than 23–26 days, even with prey provided, suggesting an obligate symbiosis with its algal endosymbiont. A method for inducing sexual reproduction in other convolutrilobids is presented, as are suggestions for successful shipping of these acoels.

scholarly journals Breakdown of the coral-algae symbiosis: towards formalising a linkage between warm-water bleaching thresholds and the growth rate of the intracellular zooxanthellae

2012 ◽  
Vol 9 (7) ◽  
pp. 8111-8139 ◽  
Author(s):  
S. A. Wooldridge
Keyword(s):  
Thermal Damage ◽  
Coral Host ◽  
Crucial Importance ◽  
Thermal Bleaching ◽  
Photosynthetic Carbon ◽  
Carbon Concentrating Mechanisms ◽  
Algal Endosymbiont ◽  
Photosynthetic Machinery ◽  
Characteristic Growth ◽  
Rapid Environmental Change

Abstract. Impairment of the photosynthetic machinery of the algal endosymbiont ("zooxanthellae") is the proximal trigger for the thermal breakdown of the coral-algae symbiosis ("coral bleaching"). Yet, the primary site of thermal damage is not well resolved. In this perspective essay, I consider further a recent hypothesis which proposes an energetic disruption to the carbon-concentrating mechanisms (CCMs) of the coral host, and the resultant onset of CO2-limitation within the photosynthetic "dark reactions", as a unifying cellular mechanism. The hypothesis identifies the enhanced retention of photosynthetic carbon for zooxanthellae (re)growth following an initial irradiance-driven expulsion event as the cause of the energetic disruption. If true, then it implies that the onset of the bleaching syndrome and setting of upper thermal bleaching limits are emergent attributes of the coral symbiosis that are ultimately underpinned by the characteristic growth profile of the intracellular zooxanthellae; which is known to depend not just on temperature, but also external (seawater) nutrient availability and zooxanthellae genotype. Here, I review this proposed bleaching linkage at a variety of observational scales, and find it to be parsimonious with the available evidence. This provides a new standpoint to consider the future prospects of the coral symbiosis in an era of rapid environmental change, including the now crucial importance of reef water quality in co-determining thermal bleaching resistance.

scholarly journals Insights into viral community composition of the cnidarian model metaorganism Aiptasia using RNA-Seq data

2017 ◽  
Author(s):  
Jan D Brüwer ◽  
Christian R Voolstra
Keyword(s):  
Community Composition ◽  
Well Being ◽  
Rna Seq ◽  
Viral Origin ◽  
Viral Community ◽  
Coral Reef Ecosystems ◽  
Algal Endosymbiont ◽  
Endosymbiotic Algae ◽  
Multicellular Organisms ◽  
Insight Into

Current research posits that all multicellular organisms live in symbioses with associated microorganisms and form so-called metaorganisms or holobionts. Cnidarian metaorganisms are of specific interest given that stony corals provide the foundation of the globally threatened coral reef ecosystems and their well-being strongly relies on forming mutualistic relationships with endosymbiotic algae of the genus Symbiodinium. So far, only few studies characterized viral diversity and the potential underlying functional importance to coral holobionts. Here we analyzed an existing RNA-Seq dataset of the coral model metaorganism Aiptasia CC7 (sensu Exaiptasia pallida) associated with aposymbiotic, partially populated, and fully symbiotic anemones with Symbiodinium to gain further insight into viral community composition and the relation to the algal endosymbiosis. Our approach included the selective removal of anemone host and algal endosymbiont sequences and subsequent microbial sequence annotation. Of a total of 297 million raw sequence reads, 8.6 million (~ 3%) remained after host and endosymbiont sequence removal. Of these, 3,293 sequences (paired-end read pairs) could be assigned as of viral origin. Taxonomic annotation shows that Aiptasia is associated with a diverse viral community consisting of 116 viral taxa covering 40 families. The viral community was dominated by viruses from the families Herpesviridae (12.00%), Partitiviridae (9.93%), and Picornaviridae (9.87%). Despite an overall stable viral community, we found that some viral taxa significantly changed in relative abundance when Aiptasia engage in a symbiotic relationship with Symbiodinium. Elucidation of viral taxa consistently present in all samples revealed an Aiptasia core virome of 15 viral taxa from 11 viral families that was comprised of many viruses previously reported in coral viromes. Our study provides a first insight into the viral community of Aiptasia. Aiptasia seem to harbor a diverse and overall stable viral community, although certain members change in abundance when the anemone host associates with its algal endosymbiont. However, the functional significance of this remains to be determined.

scholarly journals Phylogenomics invokes the clade housing Cryptista, Archaeplastida, and Microheliella maris

2021 ◽  
Author(s):  
Euki Yazaki ◽  
Akinori Yabuki ◽  
Ayaka Imaizumi ◽  
Keitaro Kume ◽  
Tetsuo Hashimoto ◽  
...  
Keyword(s):  
Large Scale ◽  
Phylogenetic Signal ◽  
Taxon Sampling ◽  
Secondary Endosymbiosis ◽  
The Novel ◽  
Sister Relationship ◽  
Homologous Genes ◽  
Gene Alignment ◽  
Red Algal ◽  
Algal Endosymbiont

AbstractAs-yet-undescribed branches in the tree of eukaryotes are potentially represented by some of “orphan” protists (unicellular micro-eukaryotes), of which phylogenetic affiliations have not been clarified in previous studies. By clarifying the phylogenetic positions of orphan protists, we may fill the previous gaps in the diversity of eukaryotes and further uncover the novel affiliation between two (or more) major lineages in eukaryotes. Microheliella maris was originally described as a member of the phylum Heliozoa, but a pioneering large-scale phylogenetic analysis failed to place this organism within the previously described species/lineages with confidence. In this study, we analyzed a 319-gene alignment and demonstrated that M. maris represents a basal lineage of one of the major eukaryotic lineages, Cryptista. We here propose a new clade name “Pancryptista” for Cryptista plus M. maris. The 319-gene analyses also indicated that M. maris is a key taxon to recover the monophyly of Archaeplastida and the sister relationship between Archaeplastida and Pancryptista, which is collectively called as “CAM clade” here. Significantly, Cryptophyceae tend to be attracted to Rhodophyta depending on the taxon sampling (ex., in the absence of M. maris and Rhodelphidia) and the particular phylogenetic “signal” most likely hindered the stable recovery of the monophyly of Archaeplastida in previous studies. We hypothesize that many cryptophycean genes (including those in the 319-gene alignment) recombined partially with the homologous genes transferred from the red algal endosymbiont during secondary endosymbiosis and bear a faint phylogenetic affinity to the rhodophytan genes.

scholarly journals Symbiotic lifestyle triggers drastic changes in the gene expression of the algal endosymbiont Breviolum minutum (Symbiodiniaceae)

2019 ◽  
Vol 10 (1) ◽  
pp. 451-466 ◽  
Author(s):  
Keren Maor‐Landaw ◽  
Madeleine J. H. Oppen ◽  
Geoffrey I. McFadden
Keyword(s):  
Gene Expression ◽  
Algal Endosymbiont

The Apicoplast: An Ancient Algal Endosymbiont of Apicomplexa

2010 ◽  
pp. 253-283
Author(s):  
Swati Agrawal ◽  
Sethu Nair ◽  
Lilach Sheiner ◽  
Boris Striepen
Keyword(s):  
Algal Endosymbiont

Ultrastructure of Nucleomorph Division in Species of Cryptophyceae and its Evolutionary Implications

1982 ◽  
Vol 54 (1) ◽  
pp. 311-328
Author(s):  
SUSAN MORRALL ◽  
A. D. GREENWOOD
Keyword(s):  
Nucleic Acids ◽  
Ultrastructural Study ◽  
Nuclear Division ◽  
Mitotic Division ◽  
Red Algal ◽  
Division Process ◽  
Algal Endosymbiont

An ultrastructural study of nucleomorphs in species of Cryptophyceae revealed aspects of division not previously reported, including the formation of a structured fibrous system, which accompanies the ordered alignment, duplication and separation into two groups of the densely staining particles typically characteristic of each nucleomorph. Despite reports indicating the presence of nucleic acids in the nucleomorph, the division process appears to be unlike any known form of nuclear division. However, the possibility exists that the nucleomorph represents the nucleus of a primitive ancestral red algal endosymbiont displaying a form so antique that its nuclear division bears no resemblance to any other known form of mitotic division.

scholarly journals Prevalent endosymbiont zonation shapes the depth distributions of scleractinian coral species

2015 ◽  
Vol 2 (2) ◽  
pp. 140297 ◽  
Author(s):  
Pim Bongaerts ◽  
Margaux Carmichael ◽  
Kyra B. Hay ◽  
Linda Tonk ◽  
Pedro R. Frade ◽  
...  
Keyword(s):  
Coral Species ◽  
Marine Invertebrate ◽  
Common Species ◽  
Coral Host ◽  
Depth Range ◽  
Dominant Feature ◽  
Vertical Distributions ◽  
Wide Scale ◽  
Algal Endosymbiont ◽  
Depth Distributions

Bathymetric distributions of photosynthetic marine invertebrate species are relatively well studied, however the importance of symbiont zonation (i.e. hosting of distinct algal endosymbiont communities over depth) in determining these depth distributions still remains unclear. Here, we assess the prevalence of symbiont zonation in tropical scleractinian corals by genotyping the Symbiodinium of the 25 most common species over a large depth range (down to 60 m) on a Caribbean reef. Symbiont depth zonation was found to be common on a reef-wide scale (11 out of 25 coral species), and a dominant feature in species with the widest depth distributions. With regards to reproductive strategy, symbiont zonation was more common in broadcasting species, which also exhibited a higher level of polymorphism in the symbiont zonation (i.e. number of different Symbiodinium profiles involved). Species with symbiont zonation exhibited significantly broader depth distributions than those without, highlighting the role of symbiont zonation in shaping the vertical distributions of the coral host. Overall, the results demonstrate that coral reefs can consist of highly structured communities over depth when considering both the coral host and their obligate photosymbionts, which probably has strong implications for the extent of connectivity between shallow and mesophotic habitats.

scholarly journals Natural spatial variability of algal endosymbiont density in the coralAcropora globiceps: a small-scale approach along environmental gradients around Moorea (French Polynesia)

2013 ◽  
Vol 94 (1) ◽  
pp. 65-74 ◽  
Author(s):  
Ophélie Ladrière ◽  
Lucie Penin ◽  
Elodie Van Lierde ◽  
Jeremie Vidal-Dupiol ◽  
Mohsen Kayal ◽  
...  
Keyword(s):  
Light Intensity ◽  
Spatial Variability ◽  
Environmental Gradients ◽  
Spatial Scales ◽  
French Polynesia ◽  
Small Scale ◽  
Depth Gradient ◽  
Potential Link ◽  
Algal Endosymbiont ◽  
Moorea Island

This study provides a baseline describing natural small scale variability ofSymbiodiniumdensity in the sentinel coralAcropora globicepsduring the summer, under non-bleaching conditions. Spatial scales investigated range from the colony scale (1–10 cm, i.e. among branches of the same colony) to the reef scale (1–10 km, i.e. among stations distributed over several locations and depths), at Moorea Island, French Polynesia. The coral–Symbiodiniumsymbiosis is a key process in scleractinian coral physiology, andSymbiodiniumdensity provides an easy-to-measure and inexpensive biomarker of this symbiosis health. Spatial variability of three major environmental factors: light intensity, sedimentation and water motion was also assessed to evaluate their potential link withSymbiodiniumdensity. Density ofSymbiodiniumdid not significantly differ within colonies or among colonies within a station. However, a marked depth gradient was observed, showing increasing density with increasing depth and decreasing light intensity. These observations provide an interesting reference for forthcoming comparisons with disturbed conditions, such as bleaching events.

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