Extensive hydrogen supersaturations in the western South Atlantic Ocean suggest substantial underestimation of nitrogen fixation

The nitrogen cycle is fundamental to Earth's biogeochemistry. Yet major uncertainties of quantification remain, particularly regarding the global oceanic nitrogen fixation rate. Hydrogen is produced during nitrogen fixation and will become supersaturated in surface waters if there is net release from diazotrophs. Ocean surveys of hydrogen supersaturation thus have the potential to illustrate the spatial and temporal distribution of nitrogen fixation, and to guide the far more onerous but quantitative methods for measuring it. Here we present the first transect of high resolution measurements of hydrogen supersaturations in surface waters along a meridional 10,000 km cruise track through the Atlantic. We compare measured saturations with published measurements of nitrogen fixation rates and also with model-derived values. If the primary source of excess hydrogen is nitrogen fixation and has a hydrogen release ratio similar to Trichodesmium, our hydrogen measurements would point to similar rates of fixation in the North and South Atlantic, roughly consistent with modelled fixation rates but not with measured rates, which are lower in the south. Possible explanations would include any substantial nitrogen fixation by newly discovered diazotrophs, particularly any having a hydrogen release ratio similar to or exceeding that of Trichodesmium; under-sampling of nitrogen fixation south of the equator related to excessive focus on Trichodesmium; and methodological shortcomings of nitrogen fixation techniques that cause a bias towards colonial diazotrophs relative to unicellular forms. Alternatively our data are affected by an unknown hydrogen source that is greater in the southern half of the cruise track than the northern

The Borrelia afzelii outer membrane protein BAPKO_0422 binds human Factor-H and is predicted to form a membrane-spanning beta-barrel

The deep evolutionary history of the Spirochetes places their branch point early in the evolution of the diderms, before the divergence of the present day Proteobacteria. As a Spirochete, the morphology of the Borrelia cell envelope shares characteristics of both Gram-positive and Gram-negative bacteria. A thin layer of peptidoglycan, tightly associated with the cytoplasmic membrane is surrounded by a more labile outer membrane (OM). This OM is rich in lipoproteins but with few known integral membrane proteins. The OmpA domain is an eight-stranded membrane-spanning β-barrel, highly conserved among the Proteobacteria but so far unknown in the Spirochetes. In the present work we describe the identification of four novel OmpA-like β-barrels from Borrelia afzelii, the most common cause of erythema migrans rash in Europe. Structural characterisation of one these proteins (BAPKO_0422) by small angle X-ray scattering (SAXS) and circular dichroism indicate a compact globular structure rich in β-strand consistent with a monomeric β-barrel. Ab initio molecular envelopes calculated from the scattering profile are consistent with homology models and demonstrate that BAPKO_0422 adopts a peanut shape with dimensions 25 x 45 Å. Deviations from the standard C-terminal signature sequence are apparent; in particular the C-terminal Phe residue commonly found in Proteobacterial OM proteins is replaced by Ile/Leu or Asn. BAPKO_0422 is demonstrated to bind human factor-H and therefore may contribute to immune evasion by inhibition of the complement response. Encoded by chromosomal genes, these proteins are highly conserved between Borrelia subspecies and may be of diagnostic or therapeutic value

Preparation of a Polymeric Foam: An Activity Designed to Increase Teachers’ Awareness of the Utility of Condensation Polymerisation

The new Scottish ‘Curriculum for Excellence’ places a greater emphasis on the societal implications of Chemistry concepts, including polymer chemistry. This has led to many Scottish secondary school teachers having little experience and background knowledge with which to satisfactorily explore the topic of polymers as they deliver the curriculum. Here we detail our development of a practical demonstration of polymer 15 foams and its inclusion in a continuous professional development module for Scottish secondary school teachers. This demonstration has now been incorporated into chemistry classrooms across Scotland as a means of exemplifying the topic of polymers

Effects of antiplatelet therapy on stroke risk by brain imaging features of intracerebral haemorrhage and cerebral small vessel diseases: subgroup analyses of the RESTART randomised, open-label trial

Background Findings from the RESTART trial suggest that starting antiplatelet therapy might reduce the risk of recurrent symptomatic intracerebral haemorrhage compared with avoiding antiplatelet therapy. Brain imaging features of intracerebral haemorrhage and cerebral small vessel diseases (such as cerebral microbleeds) are associated with greater risks of recurrent intracerebral haemorrhage. We did subgroup analyses of the RESTART trial to explore whether these brain imaging features modify the effects of antiplatelet therapy

Molecular Longitudinal Tracking of Mycobacterium abscessus spp. during Chronic Infection of the Human Lung

<div><p>The <i>Mycobacterium abscessus</i> complex is an emerging cause of chronic pulmonary infection in patients with underlying lung disease. The <i>M. abscessus</i> complex is regarded as an environmental pathogen but its molecular adaptation to the human lung during long-term infection is poorly understood. Here we carried out a longitudinal molecular epidemiological analysis of 178 <i>M. abscessus</i> spp. isolates obtained from 10 cystic fibrosis (CF) and 2 non CF patients over a 13 year period. Multi-locus sequence and molecular typing analysis revealed that 11 of 12 patients were persistently colonized with the same genotype during the course of the infection while replacement of a <i>M. abscessus sensu stricto</i> strain with a <i>Mycobacterium massiliense</i> strain was observed for a single patient. Of note, several patients including a pair of siblings were colonized with closely-related strains consistent with intra-familial transmission or a common infection reservoir. In general, a switch from smooth to rough colony morphology was observed during the course of long-term infection, which in some cases correlated with an increasing severity of clinical symptoms. To examine evolution during long-term infection of the CF lung we compared the genome sequences of 6 sequential isolates of <i>Mycobacterium bolletii</i> obtained from a single patient over an 11 year period, revealing a heterogeneous clonal infecting population with mutations in regulators controlling the expression of virulence factors and complex lipids. Taken together, these data provide new insights into the epidemiology of <i>M. abscessus</i> spp. during long-term infection of the CF lung, and the molecular transition from saprophytic organism to human pathogen.</p></div

The Cross-Talk between Spirochetal Lipoproteins and Immunity

Spirochetal diseases such as syphilis, Lyme disease and leptospirosis are major threats to public health. However the immunopathogenesis of these diseases has not been fully elucidated. Spirochetes interact with the host through various structural components such as lipopolysaccharides (LPS), surface lipoproteins and glycolipids. Although spirochetal antigens such as LPS and glycolipids may contribute to the inflammatory response during spirochetal infections, spirochetes such as Treponema pallidum and Borrelia burgdorferi lack LPS. Lipoproteins are most abundant proteins that are expressed in all spirochetes and often determine how spirochetes interact with their environment. Lipoproteins are proinflammatory, may regulate responses from both innate and adaptive immunity and enable the spirochetes to adhere to the host or the tick midgut or to evade the immune system. However, most of the spirochetal lipoproteins have unknown function. Herein, the immunomodulatory effects of spirochetal lipoproteins are reviewed and are grouped into two main categories: effects related to immune evasion and effects related to immune activation. Understanding lipoprotein-induced immunomodulation will aid in elucidating innate immunopathogenesis processes and subsequent adaptive mechanisms potentially relevant to spirochetal disease vaccine development and to inflammatory events associated with spirochetal diseases

Public space CCTV in Scotland: Local Authority responses

Local Authority survey responses and Interview data anonymised. Some of this data is restricted. Please see statement on access conditions and if you meet the criteria use 'Request Data' to be sent a link to download

Public Space CCTV in Scotland: Police Scotland responses

Police Scotland survey responses and interview data anonymised. Some of this data is restricted. Please see statement on access conditions and if you meet the criteria use 'Request Data' to be sent a link to download

Preferably Plinian and Pumaceous: Implications of Microbial Activity in Modern Volcanic Deposits at Askja Volcano, Iceland, and Relevancy for Mars Exploration

To search more efficiently for a record of past life on Mars, it is critical to know where to look and thus maximize the likelihood of success. Large-scale site selection for the Mars 2020 mission has been completed, but small (meter to 10 cm)-scale relationships of microenvironments will not be known until the rover reaches the surface. Over a 2 m transect at a modern volcanic deposit on the flank of Askja volcano in the barren highlands of Iceland, we compared two biological indicators (ATP activity and 16SrRNA amplicon sequence composition) to physical characteristics including bulk chemical composition, spectral signatures of mineralogy, and grain size. Using analytical instrumentation analogous to those available on Mars rovers, we were able to characterize the geological setting of the deposits and link physical parameters to microbial abundance and diversity. In general, methanogenesis, methanotrophy/methylotrophy, and nitrate reduction were the functional traits most associated with microbial community shift along the transect. Core microbiome members tended to be associated with nitrate reduction, and relative abundance of core microbes was strongly related to free water in the deposit. Community compositional shift of the rare microbiome was related to microenvironmental changes such as change in grain size, geochemistry, and age of deposit. These correlations lead us to suggest a sampling strategy that accounts for Martian geology, looking for undisturbed (not remobilized) explosive volcanic ash below pumice that could maximize diversity and abundance of different bioindicators. Our study also illustrates the importance of studying the variability across microenvironments in low biomass settings on earth