Effects of the toxic dinoflagellate, Alexandrium pacificum, on the marine diatom, Chaetoceros muelleri, and mussel (Perna canaliculus) sperm and hemocytes.

Harmful algal blooms (HABs) of Alexandrium pacificum have affected the Marlborough Sounds in New Zealand since 2010, posing a threat to green-lipped mussel (GLM, Perna canaliculus) farming. Previous studies have shown A. pacificum has negative effects GLM embryos and larvae.

An atlas of spider development at single-cell resolution provides new insights into arthropod embryogenesis.

Spiders are a diverse order of chelicerates that diverged from other arthropods over 500 million years ago. Research on spider embryogenesis, particularly studies using the common house spider Parasteatoda tepidariorum, has made important contributions to understanding the evolution of animal development, including axis formation, segmentation, and patterning. However, we lack knowledge about the cells that build spider embryos, their gene expression profiles and fate.

Annelid adult cell type diversity and their pluripotent cellular origins.

Many annelids can regenerate missing body parts or reproduce asexually, generating all cell types in adult stages. However, the putative adult stem cell populations involved in these processes, and the diversity of cell types generated by them, are still unknown. To address this, we recover 75,218 single cell transcriptomes of the highly regenerative and asexually-reproducing annelid Pristina leidyi.

Exposure to Alexandrium spp. impairs the development of Green-lipped mussel (Perna canaliculus) embryos and larvae.

The green-lipped mussel (GLM) Perna canaliculus is an economically, ecologically, and culturally important species in Aotearoa New Zealand. Since 2011, harmful algal blooms (HABs) of Alexandrium spp. have occurred annually in the Marlborough Sounds, the largest GLM aquaculture region in New Zealand.

A Small Change With a Twist Ending: A Single Residue in EGF-CFC Drives Bilaterian Asymmetry.

Asymmetries are essential for proper organization and function of organ systems. Genetic studies in bilaterians have shown signaling through the Nodal/Smad2 pathway plays a key, conserved role in the establishment of body asymmetries. Although the main molecular players in the network for the establishment of left-right asymmetry (LRA) have been deeply described in deuterostomes, little is known about the regulation of Nodal signaling in spiralians.

ACME dissociation: a versatile cell fixation-dissociation method for single-cell transcriptomics.

Single-cell sequencing technologies are revolutionizing biology, but they are limited by the need to dissociate live samples. Here, we present ACME (ACetic-MEthanol), a dissociation approach for single-cell transcriptomics that simultaneously fixes cells. ACME-dissociated cells have high RNA integrity, can be cryopreserved multiple times, and are sortable and permeable.

Single individual structural variant detection uncovers widespread hemizygosity in molluscs.

The advent of complete genomic sequencing has opened a window into genomic phenomena obscured by fragmented assemblies. A good example of these is the existence of hemizygous regions of autosomal chromosomes, which can result in marked differences in gene content between individuals within species. While these hemizygous regions, and presence/absence variation of genes that can result, are well known in plants, firm evidence has only recently emerged for their existence in metazoans.

Striking parallels between dorsoventral patterning in and reveal a complex evolutionary history behind a model gene regulatory network.

Dorsoventral pattering relies on Toll and BMP signalling in all insects studied so far, with variations in the relative contributions of both pathways. and the beetle share extensive dependence on Toll, while representatives of more distantly related lineages like the wasp and bug rely more strongly on BMP signalling. Here, we show that in the cricket , an evolutionarily distant outgroup, Toll has, like in , a direct patterning role for the ventral half of the embryo.

Mitochondrial evolution in the Demospongiae (Porifera): Phylogeny, divergence time, and genome biology.

The sponge class Demospongiae is the most speciose and morphologically diverse in the phylum Porifera, and the species within it are vital components of a range of ecosystems worldwide. Despite their ubiquity, a number of recalcitrant problems still remain to be solved regarding their phylogenetic inter-relationships, the timing of their appearance, and their mitochondrial biology, the latter of which is only beginning to be investigated. Here we generated 14 new demosponge mitochondrial genomes which, alongside previously published mitochondrial resources, were used to address these issues.

Tracing animal genomic evolution with the chromosomal-level assembly of the freshwater sponge Ephydatia muelleri.

The genomes of non-bilaterian metazoans are key to understanding the molecular basis of early animal evolution. However, a full comprehension of how animal-specific traits, such as nervous systems, arose is hindered by the scarcity and fragmented nature of genomes from key taxa, such as Porifera. Ephydatia muelleri is a freshwater sponge found across the northern hemisphere.

Sponge microbiome stability during environmental acquisition of highly specific photosymbionts.

In this study, we used in situ transplantations to provide the first evidence of horizontal acquisition of cyanobacterial symbionts by a marine sponge. The acquisition of the symbionts by the host sponge Petrosia ficiformis, which was observed in distinct visible patches, appeared several months after transplantation and at different times on different sponge specimens. We further used 16S rRNA gene amplicon sequencing of genomic DNA (gDNA) and complementary DNA (cDNA) and metatranscriptomics to investigate how the acquisition of the symbiotic cyanobacterium Candidatus Synechococcus feldmannii perturbed the diverse microbiota associated with the host P.

The gene-rich genome of the scallop Pecten maximus.

Background: The king scallop, Pecten maximus, is distributed in shallow waters along the Atlantic coast of Europe. It forms the basis of a valuable commercial fishery and plays a key role in coastal ecosystems and food webs. Like other filter feeding bivalves it can accumulate potent phytotoxins, to which it has evolved some immunity.

Warm temperatures, cool sponges: the effect of increased temperatures on the Antarctic sponge sp.

Although the cellular and molecular responses to exposure to relatively high temperatures (acute thermal stress or heat shock) have been studied previously, only sparse empirical evidence of how it affects cold-water species is available. As climate change becomes more pronounced in areas such as the Western Antarctic Peninsula, both long-term and occasional acute temperature rises will impact species found there, and it has become crucial to understand the capacity of these species to respond to such thermal stress. Here, we use the Antarctic sponge sp.

The utility of micro-computed tomography for the non-destructive study of eye microstructure in snails.

Molluscan eyes exhibit an enormous range of morphological variation, ranging from tiny pigment-cup eyes in limpets, compound eyes in ark clams and pinhole eyes in Nautilus, through to concave mirror eyes in scallops and the large camera-type eyes of the more derived cephalopods. Here we assess the potential of non-destructive micro-computed tomography (µ-CT) for investigating the anatomy of molluscan eyes in three species of the family Solariellidae, a group of small, deep-sea gastropods. We compare our results directly with those from traditional histological methods applied to the same specimens, and show not only that eye microstructure can be visualised in sufficient detail for meaningful comparison even in very small animals, but also that μ-CT can provide additional insight into gross neuroanatomy without damaging rare and precious specimens.

Symbiosis, Selection, and Novelty: Freshwater Adaptation in the Unique Sponges of Lake Baikal.

Freshwater sponges (Spongillida) are a unique lineage of demosponges that secondarily colonized lakes and rivers and are now found ubiquitously in these ecosystems. They developed specific adaptations to freshwater systems, including the ability to survive extreme thermal ranges, long-lasting dessication, anoxia, and resistance to a variety of pollutants. Although spongillids have colonized all freshwater systems, the family Lubomirskiidae is endemic to Lake Baikal and plays a range of key roles in this ecosystem.

Population substructure and signals of divergent adaptive selection despite admixture in the sponge Dendrilla antarctica from shallow waters surrounding the Antarctic Peninsula.

Antarctic shallow-water invertebrates are exceptional candidates to study population genetics and evolution, because of their peculiar evolutionary history and adaptation to extreme habitats that expand and retreat with the ice sheets. Among them, sponges are one of the major components, yet population connectivity of none of their many Antarctic species has been studied. To investigate gene flow, local adaptation and resilience to near-future changes caused by global warming, we sequenced 62 individuals of the sponge Dendrilla antarctica along the Western Antarctic Peninsula (WAP) and the South Shetlands (spanning ~900 km).

Trimitomics: An efficient pipeline for mitochondrial assembly from transcriptomic reads in nonmodel species.

Mitochondrial resources are of known utility to many fields of phylogenetic, population and molecular biology. Their combination of faster and slower-evolving regions and high copy number enables them to be used in many situations where other loci are unsuitable, with degraded samples and after recent speciation events.The advent of next-generation sequencing technologies (and notably the Illumina platform) has led to an explosion in the number of samples that can be studied at transcriptomic level, at relatively low cost.

Delegating Sex: Differential Gene Expression in Stolonizing Syllids Uncovers the Hormonal Control of Reproduction.

Stolonization in syllid annelids is a unique mode of reproduction among animals. During the breeding season, a structure resembling the adult but containing only gametes, called stolon, is formed generally at the posterior end of the animal. When stolons mature, they detach from the adult and gametes are released into the water column.

Probing recalcitrant problems in polyclad evolution and systematics with novel mitochondrial genome resources.

For their apparent morphological simplicity, the Platyhelminthes or "flatworms" are a diverse clade found in a broad range of habitats. Their body plans have however made them difficult to robustly classify. Molecular evidence is only beginning to uncover the true evolutionary history of this clade.

Mitochondrial genome and polymorphic microsatellite markers from the abyssal sponge Lim & Wiklund, 2017: tools for understanding the impact of deep-sea mining.

The abyssal demosponge is endemic to the Clarion - Clipperton Zone (CCZ) in the NE Pacific, a region with abundant seafloor polymetallic nodules and of potential interest for mining. encrusts on these nodules and is an abundant component of the ecosystem. To assess the impact of mining operations, it is crucial to understand the genetics of this species, because its genetic diversity and connectivity across the area may be representative of other nodule-encrusting invertebrate epifauna.

Towards the identification of ancestrally shared regenerative mechanisms across the Metazoa: A Transcriptomic case study in the Demosponge Halisarca caerulea.

Regeneration is an essential process for all multicellular organisms, allowing them to recover effectively from internal and external injury. This process has been studied extensively in a medical context in vertebrates, with pathways often investigated mechanistically, both to derive increased understanding and as potential drug targets for therapy. Several species from other parts of the metazoan tree of life, including Hydra, planarians and echinoderms, noted for their regenerative capabilities, have previously been targeted for study.

Deep, multi-stage transcriptome of the schistosomiasis vector Biomphalaria glabrata provides platform for understanding molluscan disease-related pathways.

Background: The gastropod mollusc Biomphalaria glabrata is well known as a vector for the tropical disease schistosomiasis, which affects nearly 200 million people worldwide. Despite intensive study, our understanding of the genetic basis of B. glabrata development, growth and disease resistance is constrained by limited genetic resources, constraints for which next-generation sequencing methods provide a ready solution.