Southern Ocean pteropods at risk from ocean warming and acidification

Early life stages of marine calcifiers are particularly vulnerable to climate change. In the Southern Ocean aragonite undersaturation events and areas of rapid warming already occur and are predicted to increase in extent. Here, we present the first study to successfully hatch the polar pteropod Limacina helicina antarctica and observe the potential impact of exposure to increased temperature and aragonite undersaturation resulting from ocean acidification (OA) on the early life stage survival and shell morphology. High larval mortality (up to 39%) was observed in individuals exposed to perturbed conditions. Warming and OA induced extensive shell malformation and dissolution, respectively, increasing shell fragility. Furthermore, shell growth decreased, with variation between treatments and exposure time. Our results demonstrate that short-term exposure through passing through hotspots of OA and warming poses a serious threat to pteropod recruitment and long-term population viability

Effects of Hormone Agonists on Sf9 Cells, Proliferation and Cell Cycle Arrest

Methoxyfenozide and methoprene are two insecticides that mimic the action of the main hormones involved in the control of insect growth and development, 20-hydroxyecdysone and juvenile hormone. We investigated their effect on the Spodoptera frugiperda Sf9 cell line. Methoxyfenozide was more toxic than methoprene in cell viability tests and more potent in the inhibition of cellular proliferation. Cell growth arrest occurred in the G2/M phase after a methoprene treatment and more modestly in G1 after methoxyfenozide treatment. Microarray experiments and real-time quantitative PCR to follow the expression of nuclear receptors ultraspiracle and ecdysone receptor were performed to understand the molecular action of these hormone agonists. Twenty-six genes were differentially expressed after methoxyfenozide treatment and 55 genes after methoprene treatment with no gene in common between the two treatments. Our results suggest two different signalling pathways in Sf9 cells

Trace element high-resolution distribution in abalone shell along isochronous growth layers

National audienc

Expression of biomineralisation genes in tissues and cultured cells of the abalone Haliotis tuberculata

Mollusc shell biomineralisation involves a variety of organic macromolecules (matrix proteins and enzymes) that control calcium carbonate (CaCO(3)) deposition, growth of crystals, the selection of polymorph, and the microstructure of the shell. Since the mantle and the hemocytes play an important role in the control of shell formation, primary cell cultures have been developed to study the expression of three biomineralisation genes recently identified in the abalone Haliotis tuberculata: a matrix protein, Lustrin A, and two carbonic anhydrase enzymes. Mantle cells and hemocytes were successfully maintained in primary cultures and were evaluated for their viability and proliferation over time using a semi-automated assay (XTT). PCR and densitometric analysis were used to semi-quantify the gene expression and compare the level of expression in native tissues and cultured cells. The results demonstrated that the three genes of interest were being expressed in abalone tissues, with expression highest in the mantle and much lower in the hemocytes and the gills. Biomineralisation genes were also expressed significantly in mantle cells, confirming that primary cultures of target tissues are suitable models for in vitro investigation of matrix protein secretion

Shell growth, microstructure and composition over the development cycle of the European abalone Haliotis tuberculata

International audienc

Investigating the establishment of primary cell culture from different abalone (Haliotis midae) tissues

The abalone, Haliotis midae, is the most valuable commodity in South African aquaculture. The increasing demand for marine shellfish has stimulated research on the biology and physiology of target species in order to improve knowledge on growth, nutritional requirements and pathogen identification. The slow growth rate and long generation time of abalone restrict efficient design of in vivo experiments. Therefore, in vitro systems present an attractive alternative for short term experimentation. The use of marine invertebrate cell cultures as a standardised and controlled system to study growth, endocrinology and disease contributes to the understanding of the biology of economically important molluscs. This paper investigates the suitability of two different H. midae tissues, larval and haemocyte, for establishing primary cell cultures. Cell cultures are assessed in terms of culture initiation, cell yield, longevity and susceptibility to contamination. Haliotis midae haemocytes are shown to be a more feasible tissue for primary cell culture as it could be maintained without contamination more readily than larval cell cultures. The usefulness of short term primary haemocyte cultures is demonstrated here with a growth factor trial. Haemocyte cultures can furthermore be used to relate phenotypic changes at the cellular level to changes in gene expression at the molecular level