SHARPIN forms a linear ubiquitin ligase complex regulating NF-κB activity and apoptosis

SHARPIN is a ubiquitin-binding and ubiquitin-like-domain-containing protein which, when mutated in mice, results in immune system disorders and multi-organ inflammation. Here we report that SHARPIN functions as a novel component of the linear ubiquitin chain assembly complex (LUBAC) and that the absence of SHARPIN causes dysregulation of NF-κB and apoptotic signalling pathways, explaining the severe phenotypes displayed by chronic proliferative dermatitis (cpdm) in SHARPIN-deficient mice. Upon binding to the LUBAC subunit HOIP (also known as RNF31), SHARPIN stimulates the formation of linear ubiquitin chains in vitro and in vivo. Coexpression of SHARPIN and HOIP promotes linear ubiquitination of NEMO (also known as IKBKG), an adaptor of the IκB kinases (IKKs) and subsequent activation of NF-κB signalling, whereas SHARPIN deficiency in mice causes an impaired activation of the IKK complex and NF-κB in B cells, macrophages and mouse embryonic fibroblasts (MEFs). This effect is further enhanced upon concurrent downregulation of HOIL-1L (also known as RBCK1), another HOIP-binding component of LUBAC. In addition, SHARPIN deficiency leads to rapid cell death upon tumour-necrosis factor α (TNF-α) stimulation via FADD- and caspase-8-dependent pathways. SHARPIN thus activates NF-κB and inhibits apoptosis via distinct pathways in vivo.     

Chemical and biological characteristics of desert rock pools in intermittent streams of Capitol Reef National Park, Utah

Chemical variability and biological communities of rock pools found in small desert drainage basins of Capitol Reef National Park were characterized over 8 mon in 1994. Neither flooding, drying, nor the presence or absence of surrounding vegetated wetlands had a great effect on chemical composition, which was very dilute and fluctuated somewhat in response to rain events. Neither flooding nor drying affected the composition of biological communities in the pools. Summer storms affected only a few drainages at a time, and only a few study pools of significant volume dried completely during the hot, dry summer. This suggests that only a portion of the Waterpocket Fold aquatic community is ever disturbed at a time, leaving undisturbed areas as a source of recovery. Pools bordered by vegetated wetlands always supported greater numbers of species throughout the year than those bordered only by bedrock, but the same taxa were found in both vegetated and bedrock pools. The rock pool fauna in Capitol Reef National Park appear to be resilient to climatic variability.     

State of the field: Paper tools

Paper occupies a special place in histories of knowledge. It is the substrate of communication, the stuff of archives, the bearer of marks that make worlds. For the early-modern period in particular we now have a wealth of studies of ‘paper tools’, of the ways in which archives were assembled and put to use, of the making of lists and transcribing of observations, and so on. In other fields, too, attention has turned to the materiality of information. How far is it possible to draw a stable methodology out of the insights of literary and book historians, bibliographers, anthropologists, and those working in media studies? Do these diverse fields in fact refer to the same thing when they talk of paper, its qualities, affordances and limitations? In attempting to answer these questions, the present essay begins in the rich territory of early-modern natural philosophy – but from there opens out to take in recent works in a range of disciplines. Attending to the specific qualities of paper is only possible, I argue, if it is understood that paper can be both transparent and opaque depending on the social world it inhabits and helps to constitute. Paper flickers into and out of view, and it is precisely this quality that constitutes its sociomateriality.     

Rapid worldwide depletion of predatory fish communities

Serious concerns have been raised about the ecological effects of industrialized fishing, spurring a United Nations resolution on restoring fisheries and marine ecosystems to healthy levels. However, a prerequisite for restoration is a general understanding of the composition and abundance of unexploited fish communities, relative to contemporary ones. We constructed trajectories of community biomass and composition of large predatory fishes in four continental shelf and nine oceanic systems, using all available data from the beginning of exploitation. Industrialized fisheries typically reduced community biomass by 80% within 15 years of exploitation. Compensatory increases in fast-growing species were observed, but often reversed within a decade. Using a meta-analytic approach, we estimate that large predatory fish biomass today is only about 10% of pre-industrial levels. We conclude that declines of large predators in coastal regions have extended throughout the global ocean, with potentially serious consequences for ecosystems. Our analysis suggests that management based on recent data alone may be misleading, and provides minimum estimates for unexploited communities, which could serve as the 'missing baseline' needed for future restoration efforts.     

Experimental observation of symmetry-breaking nonlinear modes in an active ring

Solitons are large-amplitude, spatially confined wave packets in nonlinear media. They occur in a wide range of physical systems, such as water surfaces, optical fibres, plasmas, Bose-Einstein condensates and magnetically ordered media. A distinguishing feature of soliton behaviour that is common to all systems, is that they propagate without a change in shape owing to the stabilizing effect of the particular nonlinearity involved. When the propagation path is closed, modes consisting of one or several solitons may rotate around the ring, the topology of which imposes additional constraints on their allowed frequencies and phases. Here we measure the mode spectrum of spin-wave solitons in a nonlinear active ring constructed from a magnetic ferrite film. Several unusual symmetry-breaking soliton-like modes are found, such as 'M?bius' solitons, which break the fundamental symmetry of 2pi-periodicity in the phase change acquired per loop: a M?bius soliton needs to travel twice around the ring to meet the initial phase condition.