Survival under conditions of variable food availability: Resource utilization and storage in the cold-water coral Lophelia pertusa

Cold‐water coral (CWC) reefs are hotspots of biodiversity and productivity in the deep sea, but their distribution is limited by the availability of food, which undergoes complex local and temporal variability. We studied the resource utilization, metabolism, and tissue storage of CWC Lophelia pertusa during an experimentally simulated 3‐day food pulse, of 13C15N‐enriched phytodetritus, followed by a 4‐week food deprivation. Oxygen consumption (0.145 μmol O2 [mmol organic carbon {OC}]−1 h−1), release of particulate organic matter (0.029 μmol particulate organic carbon [POC] [mmol OC]−1 h−1 and 0.005 μmol particulate organic nitrogen [mmol OC]−1 h−1), ammonium excretion (0.004 μmol NH4+ [mmol OC]−1 h−1), tissue C and N content, and fatty acid (FA) and amino acid composition did not change significantly during the experiment. Metabolization of the labeled phytodetritus, however, underwent distinct temporal dynamics. Initially, L. pertusa preferentially used phytodetritus‐derived C for respiration (2.2 ± 0.36 nmol C [mmol OC]−1 h−1) and mucus production (0.94 ± 0.52 nmol C [mmol OC]−1 h−1), but those tracer fluxes declined exponentially to <20% within 2 weeks after feeding and then remained stable, indicating that the remainder of the incorporated phytodetritus had entered a tissue pool with lower turnover. Analysis of 13C in individual FAs revealed a mismatch between the FAs incorporated from phytodetritus and the FA requirements of the coral. We suggest that feeding on other resources, such as lipid‐rich zooplankton, could fill this deficiency. A release of 10% of their total OC as respired C and POC during the 4‐week food deprivation underlines the importance of regular food pulses for CWC reefs.publishedVersio

Passive Observations of a Large DNS Service:2.5 Years in the Life of Google

In 2009 Google launched its Public DNS service, with its characteristic IP address 8.8.8.8. Since then, this service has grown to be the largest and most well-known DNS service in existence. The popularity of public DNS services has been disruptive for Content Delivery Networks (CDNs). CDNs rely on IP information to geo-Iocate clients. This no longer works in the presence of public resolvers, which led to the introduction of the EDNSO Client Subnet extension. ECS allows resolvers to reveal part of a client's IP address to authoritative name servers and helps CDNs pinpoint client origin. A useful side effect of ECS is that it can be used to study the workings of public DNS resolvers. In this paper, we leverage this side effect of ECS to study Google Public DNS. From a dataset of 3.7 billion DNS queries spanning 2.5 years, we extract ECS information and perform a longitudinal analysis of which clients are served from which Point-of-Presence. Our study focuses on two aspects of GPDNS. First, we show that while GPDNS has PoPs in many countries, traffic is frequently routed out of country, even if that was not necessary. Often this reduces performance, and perhaps more importantly, exposes DNS requests to state-level surveillance. Second, we study how GPDNS is used by clients. We show that end-users switch to GPDNS en masse when their ISP's DNS service is unresponsive, and do not switch back. We also find that many e-mail providers configure GPDNS as the resolver for their servers. This raises serious privacy concerns, as DNS queries from mail servers reveal information about hosts they exchange mail with. Because of GPDNS's use of ECS, this sensitive information is not only revealed to Google, but also to any operator of an authoritative name server that receives ECS-enabled queries from GPDNS during the lookup process

Recycling pathways in cold-water coral reefs: Use of dissolved organic matter and bacteria by key suspension feeding taxa

Cold-water coral (CWC) reefs are one of the most diverse and productive ecosystems in the deep sea. Especially in periods of seasonally-reduced phytodetritus food supply, their high productivity may depend on the recycling of resources produced on the reef, such as dissolved organic matter (DOM) and bacteria. Here, we demonstrate that abundant suspension feeders Geodia barretti (high-microbial-abundance sponge), Mycale lingua (low-microbial-abundance sponge) and Acesta excavata (bivalve) are able to utilize 13C-enriched (diatom-derived) DOM and bacteria for tissue growth and respiration. While DOM was an important potential resource for all taxa, utilization of bacteria was higher for the sponges as compared to the bivalve, indicating a particle-size differentiation among the investigated suspension feeders. Interestingly, all taxa released 13C-enriched particulate organic carbon, which in turn may feed the detritus pathway on the reef. Especially A. excavata produced abundant (pseudo-)fecal droppings. A second stable-isotope tracer experiment revealed that detritivorous ophiuroids utilized these droppings. The high resource flexibility of dominant reef suspension feeders, and the efficient recycling of their waste products by the detritivore community, may provide important pathways to maintain the high productivity on cold-water coral reefs, especially in periods of low external food supply.publishedVersio

Strong inhibition of TNF-α production and inhibition of IL-8 and COX-2 mRNA expression in monocyte-derived macrophages by RWJ 67657, a p38 mitogen-activated protein kinase (MAPK) inhibitor

In inflammatory processes, the p38 mitogen-activated protein kinase (MAPK) signal transduction route regulates production and expression of cytokines and other inflammatory mediators. Tumor necrosis factor α (TNF-α) is a pivotal cytokine in rheumatoid arthritis and its production in macrophages is under control of the p38 MAPK route. Inhibition of the p38 MAPK route may inhibit production not only of TNF-α, but also of other inflammatory mediators produced by macrophages, and indirectly of inflammatory mediators by other cells induced by TNF-α stimulation. Here we investigate the effects of RWJ 67657, a p38 MAPK inhibitor, on mRNA expression and protein production of TNF-α and other inflammatory mediators, in monocyte-derived macrophages. A strong inhibition of TNF-α was seen at pharmacologically relevant concentrations of RWJ 67657, but also inhibition of mRNA expression of IL-1β, IL-8, and cyclooxygenase-2 was shown. Furthermore, it was shown that monocyte-derived macrophages have a high constitutive production of matrix metalloproteinase 9, which is not affected by p38 MAPK inhibition. The results presented here may have important implications for the treatment of rheumatoid arthritis

Case Report: Using ultrasound to prevent a broken catheter from migrating to the heart.

Peripheral intravenous (IV) catheters can break off while still in the patient, with possible detrimental effects such as upstream migration to the heart. These catheters have probably been damaged by the needle during a difficult insertion. A peripheral IV catheter was removed in a 90 year old patient and only half of the catheter was retrieved. By using ultrasound examination the remaining part of the IV catheter was identified, and retrieved surgically, before it could migrate towards the heart. This case report suggests that ultrasound should not only be used for difficult placement of a peripheral IV catheter, but can also be used when removal is complicated

Survival under conditions of variable food availability: Resource utilization and storage in the cold-water coral Lophelia pertusa

Cold‐water coral (CWC) reefs are hotspots of biodiversity and productivity in the deep sea, but their distribution is limited by the availability of food, which undergoes complex local and temporal variability. We studied the resource utilization, metabolism, and tissue storage of CWC Lophelia pertusa during an experimentally simulated 3‐day food pulse, of 13C15N‐enriched phytodetritus, followed by a 4‐week food deprivation. Oxygen consumption (0.145 μmol O2 [mmol organic carbon {OC}]−1 h−1), release of particulate organic matter (0.029 μmol particulate organic carbon [POC] [mmol OC]−1 h−1 and 0.005 μmol particulate organic nitrogen [mmol OC]−1 h−1), ammonium excretion (0.004 μmol NH4+ [mmol OC]−1 h−1), tissue C and N content, and fatty acid (FA) and amino acid composition did not change significantly during the experiment. Metabolization of the labeled phytodetritus, however, underwent distinct temporal dynamics. Initially, L. pertusa preferentially used phytodetritus‐derived C for respiration (2.2 ± 0.36 nmol C [mmol OC]−1 h−1) and mucus production (0.94 ± 0.52 nmol C [mmol OC]−1 h−1), but those tracer fluxes declined exponentially to <20% within 2 weeks after feeding and then remained stable, indicating that the remainder of the incorporated phytodetritus had entered a tissue pool with lower turnover. Analysis of 13C in individual FAs revealed a mismatch between the FAs incorporated from phytodetritus and the FA requirements of the coral. We suggest that feeding on other resources, such as lipid‐rich zooplankton, could fill this deficiency. A release of 10% of their total OC as respired C and POC during the 4‐week food deprivation underlines the importance of regular food pulses for CWC reefs

Rare device landing zone ruptures after transcatheter aortic valve implantation (TAVI)

Rupture of the “device landing zone” is a rare but severe complication of transcatheter aortic valve implantation (TAVI). Recently, the small segment of muscular left ventricular outflow tract (LVOT) located between the left–right commissure and left fibrous trigone was identified as the most vulnerable region at risk of external rupture. We here provide the first pictures of a rupture adjacent to this vulnerable area, inducing a connection between the LVOT and the left atrium. We also report a case of supra-annular rupture, a less usual location of rupture. These illustrations may help pathologists and clinicians to get familiar with early rare complications of TAVI, an important new field of interest of autopsy in cardiovascular pathology