Project description:Sargassum is one of the most diverse brown algal genus with more than 150 known species, mostly benthic and few pelagic species. They contribute significantly to global primary production and serve as important habitat for wide range of marine organisms. Sargassum vulgare is one of the dominant habitat forming species along Mediterranean coast. Despite their huge ecological importance, it is relatively unknown how they will respond under future global climate change scenario. This work used de novo transcriptome sequencing approach to understand the molecular response of S. vulgare to chronic acidification at the shallow underwater volcanic CO2 vents off Ischia Island, Italy. Keywords: brown algae, Sargassum, de novo transcriptome, ocean acidification, CO2 vents.
Project description:The veined rapa whelk (Rapana venosa) is widely consumed in China but is also a predator that is reducing bivalves resources in oceans worldwide. Larval metamorphosis of this species, a pelagic to benthic transition that involves considerable structural and physiological changes, plays a pivotal role in its commercial breeding and natural populations. Thus, the endogenous microRNA that drive this transition attract considerable interest. This study is the first to investigate alterations of miRNA expression during metamorphosis in a marine gastropod by using high-throughput sequencing. A total of 195 differentially expressed miRNAs were obtained, including 65 miRNAs differentially expressed during the transition from pre-competent larva to competent larva (33 up-regulated and 32 down regulated) and 123 miRNAs differentially expressed during competent to post larva transition (96 up-regulated and 27 down regulated). Our data improve understanding of the microRNA function into R. venosa metamorphosis and provide a solid basis for further study.
Project description:In the seabed, chemical defences mediate inter- and intraspecific interactions and may determine organisms’ success, shaping the diversity and function of benthic communities. Sponges represent a prominent example of chemically-defended marine organisms with great ecological success. The ecological factors controlling the production of their defensive compounds and the evolutionary forces that select for these defences remain little understood. Each sponge species produces a specific and diverse chemical arsenal with fish-deterrent, antifouling and antimicrobial properties. However, some small animals (mesograzers), mainly sea slugs, have specialized in living and feeding on sponges. Feeding on chemically-defended organisms provides a strategy to avoid predators, albeit the poor nutritional value of sponges. In order to investigate the mechanisms that control sponge chemical defence, with particular focus on the response to specialist grazers, we investigated the interaction between the sponge Aplysina aerophoba and the sea slug Tylodina perversa. Here we performed controlled experiments and collected sponge samples at different time points (3h, 1d and 6d after treatment). To further elucidate if the sponge response is specific to grazing by T. perversa, we also included a treatment in which sponges were mechanically damaged with a scalpel. We compared gene expression between treatments based on RNA-Seq data.
Project description:Flatfish have evolved their visual system to meet the demands of their environment through a fascinating process of metamorphosis. This morphological transformation involves a significant change in lifestyle from pelagic to benthic, accompanied by changes in body structure to achieve an asymmetrical flat shape. However, the fundamental change lies in the migration of one eye from its original position to the opposite location on the body. Although the role of thyroid hormone in triggering flatfish metamorphosis is well established, the specific gene regulatory network responsible for this extraordinary eye migration is still unknown. Here we show a global view through the creation of a general map of gene expression during the metamorphic process, encompassing both migrant and non-migrant eyes. Our research uncovers significant differences between migrant and non-migrant eyes of turbot in the pre-metamorphic and climax phases, emphasizing genetic disparities crucial for benthic adaptation.
Project description:The sea cucumber Apostichopus japonicus is a deposit-feeder and vital for marine benthic ecosystems. Hypoxia lasting for several days can lead to massive mortality in A. japonicus. It is important to understand the molecular responses of A. japonicus when exposed to acute changes in DO concentration. In the present study, RNA-seq provided a general overview of the gene expression profiles of the respiratory tree of A. japonicus exposed to dissolved oxygen (DO) of 8 mg/L (DO8), 4 mg/L (DO4) and 2 mg/L (DO2) conditions.
Project description:Marine pelagic larvae from throughout the animal kingdom use a hierarchy of environmental cues to identify a suitable benthic habitat on which to settle and metamorphose into the reproductive phase of the life cycle. The majority of larvae are induced to settle by biochemical cues and many species have long been known to preferentially settle in the dark. Combined, these data suggest that larval responses to light and biochemical cues may be linked, but this is yet to be explored at the molecular level. Here, we track vertical position of larvae of the sponge Amphimedon queenslandica to show that they descend to the benthos at twilight, by which time they are competent to respond to biochemical cues, consistent with them naturally settling in the dark. We then conduct larval settlement assays under three different light regimes (natural day-night, constant dark or constant light), and use transcriptomics on individual larvae to identify candidate molecular pathways underlying the different settlement responses that we observe. We find that constant light prevents larval settlement in response to biochemical cues, likely via actively repressing chemostransduction; this is consistent with the sustained upregulation of a photosensory cryptochrome and two putative inactivators of G-protein signalling in the constant light only. We hypothesise that photo- and chemosensory systems may be hierarchically integrated into ontogeny to regulate larval settlement via nitric oxide (NO) and cyclic guanosine monophosphate (cGMP) signalling in this sponge that belongs to one of the earliest branching of the extant animal lineages.
Project description:Marine organisms represent a rich source for discovering natural products and materials that could inspire the development of novel molecules or materials for a high variety of industrial applications. Among them are sea stars, emblematic animals of the seashore. These organisms rely on epidermal secretions to cope with their benthic life. Their integument produces a mucus, which represents the first barrier against invaders; and their tube feet produce adhesive secretions to pry open mussels and attach strongly but temporarily to rocks. In this study, we investigate for the first time the protein content of mucous and adhesive secretions from the sea star Asterias rubens. These secretomes were analysed using tandem mass spectrometry and resulting MS/MS data were searched against in silico translated tube foot transcriptome. Tube foot transcripts coding for proteins identified in the two secretions were then functionally annotated by similarity searches against NCBI nr database.
Project description:This project aimed to disclose the metabolic alterations and responses of the marine mussel Mytilus galloprovincialis after grazing the toxic microalga Prorocentrum lima. Mussels metabolic alterations were investigated by shotgun proteomics, during the phases of intoxication and depuration. The diarrhetic shelllfisf toxins were also quantified in this project, for assessing the levels of contamination of mussels.