Floating seaweed as a vector for travelling organisms

The neuston, i.e. the fauna inhabiting the upper layer of oceans and seas, is strongly influenced by the occurrence of floating patches composed of detached coastal seaweed fragments. Ephemeral floating seaweeds harbour a diverse fauna originating from attached seaweeds, the strandline of beaches, the surrounding and underlying water column, the seafloor or the air. These organisms colonise the seaweeds for various reasons, usually including the provision of shelter, food or attachment substrate. The association behaviour of these organisms and their use of the resources offered by floating seaweeds potentially have important ecological consequences, such as the possibility of passive dispersal of associated fauna to new, distant locations by means of rafting. During this study, different aspects of raft-associated ecology were addressed. The results demonstrate that the habitat formed by floating seaweeds is very complex. Although the presence of floating seaweeds in the neuston can, to a certain degree, be seasonally predicted (storms, seasonal release of fertile structures), the habitat that they form is still very patchy and unstable. Consequently, most species found in association with ephemeral floating seaweed patches are opportunistic of nature. The association behaviour of the encountered species and their (optimal) use of the transient resources offered by floating seaweeds can, in certain circumstances, result in the passive dispersal of associated fauna to new, and distant locations by means of rafting. The process of rafting strongly depends on the longevity of the seaweed raft, which is in turn significantly influenced by temperature and grazing pressure. In favorable conditions, seaweed rafts can potentially cover great distances, carrying with them rafting fauna that are able to survive a long journey in the neuston

Extracellular ATP drives systemic inflammation, tissue damage and mortality

Systemic inflammatory response syndromes (SIRS) may be caused by both infectious and sterile insults, such as trauma, ischemia-reperfusion or burns. They are characterized by early excessive inflammatory cytokine production and the endogenous release of several toxic and damaging molecules. These are necessary to fight and resolve the cause of SIRS, but often end up progressively damaging cells and tissues, leading to life-threatening multiple organ dysfunction syndrome (MODS). As inflammasome-dependent cytokines such as interleukin-1 beta are critically involved in the development of MODS and death in SIRS, and ATP is an essential activator of inflammasomes in vitro, we decided to analyze the ability of ATP removal to prevent excessive tissue damage and mortality in a murine LPS-induced inflammation model. Our results indeed indicate an important pro-inflammatory role for extracellular ATP. However, the effect of ATP is not restricted to inflammasome activation at all. Removing extracellular ATP with systemic apyrase treatment not only prevented IL-1 beta accumulation but also the production of inflammasome-independent cytokines such as TNF and IL-10. In addition, ATP removal also prevented systemic evidence of cellular disintegration, mitochondrial damage, apoptosis, intestinal barrier disruption and even mortality. Although blocking ATP receptors with the broad-spectrum P2 purinergic receptor antagonist suramin imitated certain beneficial effects of apyrase treatment, it could not prevent morbidity or mortality at all. We conclude that removal of systemic extracellular ATP could be a valuable strategy to dampen systemic inflammatory damage and toxicity in SIRS

Zeevruchten: Microplastics op je bord?

Onze samenleving lijdt aan een ‘plastic passion’. Plastic is werkelijk overal. Tot in zeevruchten tref je minuscule stukjes plastic, zogenaamde microplastics, aan. Microplastics is de naam voor stukjes plastic kleiner dan 5mm. Soms zijn ze zo gemaakt, denk maar aan de plastic pellets als grondstof gebruikt in de plasticindustrie of als schuurparels in verzorgingscrubs. Maar microplastics kunnen ook ontstaan door het uiteenvallen van grote stukken plastic afval of bij het wassen van synthetische kledij. Je vindt deze plastic vezeltjes en stukjes in onder andere mosselen en Noordzeegarnalen. De aanwezigheid van microplastics in ons voedsel haalt vaak het nieuws en zorgt voor ongerustheid bij de liefhebbers van al het lekkers uit zee. Maar moeten we ons ook echt zorgen maken