Patterns of Sponge Abundance Across a Gradient of Habitat Quality in the Wakatobi Marine National Park, Indonesia

Sponges are important components of reef communities worldwide, fulfilling a number of important functional roles. Habitat degradation caused by the loss of hard corals has the potential to cause increases in sponge abundance and percentage cover as they gain access to resources such as space and food. In this study we compared sponge densities and percentage cover at sites with varying hard coral cover in the Wakatobi Marine National Park, Indonesia (WMNP). We found significant differences in sponge densities at the study sites but no significant difference in sponge densities on different surface angles. Unexpectedly, we also found a weak positive correlation between coral cover and sponge density. This indicates that spatial competition is unlikely to be the most important factor determining sponge abundance in the WMNP. In contrast to sponge density data, we found that sponge percentage cover and hard coral cover were weakly negatively correlated, but found no significant difference in sponge percentage cover between the study sites. Finally, multivariate analysis of the benthic communities at the study sites indicated that while sites with higher coral cover were characterised by coral (proportionally), lower coral cover sites were characterised by algae and sponges. This suggests that although there was no significant difference in sponge percentage cover between the study sites conditions that led to the loss of hard coral at lower quality sites mean that these sites are characterised by sponges and algae rather than by any other groups of benthic organisms

Neutrophil cannibalism – a back up when the macrophage clearance system is insufficient

BACKGROUND: During a lipopolysaccharide-induced lung inflammation, a massive accumulation of neutrophils occurs, which is normally cleared by macrophage phagocytosis following neutrophil apoptosis. However, in cases of extensive apoptosis the normal clearance system may fail, resulting in extensive neutrophil secondary necrosis. The aim of this study was to explore the hypothesis that neutrophils, in areas of the lung with extensive cellular infiltration, contribute to clearance by phagocytosing apoptotic cells and/or cell debris derived from secondary necrosis. METHODS: Intranasal lipopolysaccharide administration was used to induce lung inflammation in mice. The animals were sacrificed at seven time points following administration, bronchoalveolar lavage was performed and tissue samples obtained. Electron microscopy and histochemistry was used to assess neutrophil phagocytosis. RESULTS: Electron microscopic studies revealed that phagocytosing neutrophils was common, at 24 h after LPS administration almost 50% of the total number of neutrophils contained phagosomes, and the engulfed material was mainly derived from other neutrophils. Histochemistry on bronchoalvolar lavage cells further showed phagocytosing neutrophils to be frequently occurring. CONCLUSION: Neutrophils are previously known to phagocytose invading pathogens and harmful particles. However, this study demonstrates that neutrophils are also able to engulf apoptotic neutrophils or cell debris resulting from secondary necrosis of neutrophils. Neutrophils may thereby contribute to clearance and resolution of inflammation, thus acting as a back up system in situations when the macrophage clearance system is insufficient and/or overwhelmed

Prehospital transdermal glyceryl trinitrate in patients with ultra-acute presumed stroke (RIGHT-2): an ambulance-based, randomised, sham-controlled, blinded, phase 3 trial

Background High blood pressure is common in acute stroke and is a predictor of poor outcome; however, large trials of lowering blood pressure have given variable results, and the management of high blood pressure in ultra-acute stroke remains unclear. We investigated whether transdermal glyceryl trinitrate (GTN; also known as nitroglycerin), a nitric oxide donor, might improve outcome when administered very early after stroke onset. Methods We did a multicentre, paramedic-delivered, ambulance-based, prospective, randomised, sham-controlled, blinded-endpoint, phase 3 trial in adults with presumed stroke within 4 h of onset, face-arm-speech-time score of 2 or 3, and systolic blood pressure 120 mm Hg or higher. Participants were randomly assigned (1:1) to receive transdermal GTN (5 mg once daily for 4 days; the GTN group) or a similar sham dressing (the sham group) in UKbased ambulances by paramedics, with treatment continued in hospital. Paramedics were unmasked to treatment, whereas participants were masked. The primary outcome was the 7-level modified Rankin Scale (mRS; a measure of functional outcome) at 90 days, assessed by central telephone follow-up with masking to treatment. Analysis was hierarchical, first in participants with a confirmed stroke or transient ischaemic attack (cohort 1), and then in all participants who were randomly assigned (intention to treat, cohort 2) according to the statistical analysis plan. This trial is registered with ISRCTN, number ISRCTN26986053. Findings Between Oct 22, 2015, and May 23, 2018, 516 paramedics from eight UK ambulance services recruited 1149 participants (n=568 in the GTN group, n=581 in the sham group). The median time to randomisation was 71 min (IQR 45–116). 597 (52%) patients had ischaemic stroke, 145 (13%) had intracerebral haemorrhage, 109 (9%) had transient ischaemic attack, and 297 (26%) had a non-stroke mimic at the final diagnosis of the index event. In the GTN group, participants’ systolic blood pressure was lowered by 5·8 mm Hg compared with the sham group (p<0·0001), and diastolic blood pressure was lowered by 2·6 mm Hg (p=0·0026) at hospital admission. We found no difference in mRS between the groups in participants with a final diagnosis of stroke or transient ischaemic stroke (cohort 1): 3 (IQR 2–5; n=420) in the GTN group versus 3 (2–5; n=408) in the sham group, adjusted common odds ratio for poor outcome 1·25 (95% CI 0·97–1·60; p=0·083); we also found no difference in mRS between all patients (cohort 2: 3 [2–5]; n=544, in the GTN group vs 3 [2–5]; n=558, in the sham group; 1·04 [0·84–1·29]; p=0·69). We found no difference in secondary outcomes, death (treatment-related deaths: 36 in the GTN group vs 23 in the sham group [p=0·091]), or serious adverse events (188 in the GTN group vs 170 in the sham group [p=0·16]) between treatment groups. Interpretation Prehospital treatment with transdermal GTN does not seem to improve functional outcome in patients with presumed stroke. It is feasible for UK paramedics to obtain consent and treat patients with stroke in the ultraacute prehospital setting

Effect of elevated pCO<inf>2</inf> on the production of dimethylsulphoniopropionate (DMSP) and dimethylsulphide (DMS) in two species of Ulva (Chlorophyceae)

Concentrations of the secondary algal metabolite dimethylsulphoniopropionate (DMSP) and its breakdown product, the climate-active trace gas dimethylsulphide (DMS), are sensitive to changes in pCO2. Data on the response of marine macroalgae to future pCO2 levels are lacking. Here we report the first measurements of DMSP and DMS production in two species of chlorophyte macroalgae (Ulva lactuca and U. clathrata). Laboratory cultures were grown in pH-stated medium that received pulses of CO2 to create pCO2 conditions ranging from ambient (432 μatm) to future (1514 μatm). Intracellular concentration of DMSP remained unaffected in both species (101 ± 21 and 69 ± 20 mmol g-1 FW in U. lactuca and U. clathrata, respectively) but significant differences in extracellular production of DMSP and DMS were observed for U. lactuca: Whilst production of total DMSP (the sum of external DMSP and DMS) was different between replicated experiments, the percentage of total DMSP produced throughout each experiment increased significantly by up to 65% with increasing pCO2 to 1514 μatm. In contrast, DMS production decreased from 0. 4 to 0. 25 nmol g-1 FW h-1. This decrease was not a linear function of pCO2 but an almost 50% step-wise loss of DMS production was indicated between 635 and 884 μatm, a pCO2 predicted for the next 100 years. Since Ulva spp. form massive harmful blooms ('green tides') that can occur free-floating and faraway (>100 km) from the coast, they may provide a locally significant source of DMS to the remote marine boundary layer. © 2012 Springer Science+Business Media B.V