Category: Dinoflagellate genomics

Comparative Plastid Genomics of Green-Colored Dinoflagellates Unveils Parallel Genome Compaction and RNA Editing

Dinoflagellates possess plastids that are diverse in both pigmentation and evolutionary background. One of the plastid types found in dinoflagellates is pigmented with chlorophylls a and b (Chl a + b) and originated from the endosymbionts belonging to a small group of green algae, Pedinophyceae. The Chl a + b-containing plastids have been found in three distantly related dinoflagellates Lepidodinium spp., strain MGD, and strain TGD, and were proposed to be derived from separate partnerships…

Responses of Dinoflagellate Cells to Ultraviolet-C Irradiation

Dinoflagellates are important aquatic microbes and major harmful algal bloom (HAB) agents that form invasive species through ship ballast transfer. UV-C installations are recommended for ballast treatments and HAB controls, but there is a lack of knowledge in dinoflagellate responses to UV-C. We report here dose-dependent cell cycle delay and viability loss of dinoflagellate cells irradiated with UV-C, with significant proliferative reduction at 800 Jm^(-2) doses or higher, but immediate LD50…

Temperature variability interacts with mean temperature to influence the predictability of microbial phenotypes

Despite their relatively high thermal optima (T(opt) ), tropical taxa may be particularly vulnerable to a rising baseline and increased temperature variation because they live in relatively stable temperatures closer to their T(opt) . We examined how microbial eukaryotes with differing thermal histories responded to temperature fluctuations of different amplitudes (0 control, ±2, ±4 °C) around mean temperatures below or above their T(opt) . Cosmopolitan dinoflagellates were selected based on…

A Strategy for Gene Knockdown in Dinoflagellates

Dinoflagellates are unicellular protists that display unusual nuclear features such as large genomes, condensed chromosomes and multiple gene copies organized as tandem gene arrays. Genetic regulation is believed to be controlled at the translational rather than transcriptional level. An important player in this process is initiation factor eIF4E which binds the 7-methylguanosine cap structure (m7G) at the 5′-end of mRNA. Transcriptome analysis of eleven dinoflagellate species has established…

Taxonomic and Bioactivity Characterizations of <em>Mameliella alba</em> Strain LZ-28 Isolated from Highly Toxic Marine Dinoflagellate <em>Alexandrium catenella</em> LZT09

Microalgae host varied microbial consortium harboring cross-kingdom interactions with fundamental ecological significance in aquatic ecosystems. Revealing the complex biofunctions of the cultivable bacteria of phycosphere microbiota is one vital basis for deeply understanding the mechanisms governing these dynamic associations. In this study, a new light-yellow pigmented bacterial strain LZ-28 was isolated from the highly-toxic and harmful algal bloom-forming dinoflagellate Alexandrium catenella…

The characterization of novel monomeric creatine kinases in the early branching Alveolata species, Perkinsus marinus: Implications for phosphagen kinase evolution

The genome of the unicellular molluscan parasite Perkinsus marinus contains at least five genes coding for putative creatine kinases (CK), a phosphoryl transfer enzyme which plays a key role in cellular energy transactions. Expression and kinetic analyses of three of the P. marinus CKs revealed them to be true CKs with catalytic properties in the range of typical metazoan CKs. A sequence comparison of the P. marinus CKs with a range of CK dimers and other dimeric phosphoryl transfer enzymes in…

The in-situ release of algal bloom populations and the role of prokaryotic communities in their establishment and growth

Harmful algal blooms (HABs) may quickly travel and inoculate new water bodies via currents and runoff in estuaries. The role of in-situ prokaryotic communities in the re-establishment and growth of inoculated algal blooms remains unknown. A novel on-board incubation experiment was employed to simulate the sudden surge of algal blooms to new estuarine waters and reveal possible outcomes. A dinoflagellate (Amphidinium carterae) and a diatom species (Thalassiosira weissflogii) which had bloomed in…

Alignment-Free Analysis of Whole-Genome Sequences From Symbiodiniaceae Reveals Different Phylogenetic Signals in Distinct Regions

Dinoflagellates of the family Symbiodiniaceae are predominantly essential symbionts of corals and other marine organisms. Recent research reveals extensive genome sequence divergence among Symbiodiniaceae taxa and high phylogenetic diversity hidden behind subtly different cell morphologies. Using an alignment-free phylogenetic approach based on sub-sequences of fixed length k (i.e. k-mers), we assessed the phylogenetic signal among whole-genome sequences from 16 Symbiodiniaceae taxa (including…

Bioinformatics of Corals: Investigating Heterogeneous Omics Data from Coral Holobionts for Insight into Reef Health and Resilience

Coral reefs are home to over two million species and provide habitat for roughly 25% of all marine animals, but they are being severely threatened by pollution and climate change. A large amount of genomic, transcriptomic, and other omics data is becoming increasingly available from different species of reef-building corals, the unicellular dinoflagellates, and the coral microbiome (bacteria, archaea, viruses, fungi, etc.). Such new data present an opportunity for bioinformatics researchers and…

Development of a novel TaqMan qPCR assay for rapid detection and quantification of Gymnodinium catenatum for application to harmful algal bloom monitoring in coastal areas of Tunisia

Gymnodinium catenatum is a dinoflagellate known to cause paralytic shellfish poisoning (PSP), commonly associated with human muscular paralysis, neurological symptoms, and, in extreme cases, death. In the present work, we developed a real-time PCR-based assay for the rapid detection of the toxic microalgal species, G. catenatum, in environmental bivalve mollusc samples as well as seawater samples. G. catenatum-specific primers and probe were designed on the ITS1-5.8S-ITS2 rDNA region. Hydrolysis…