4 research outputs found

    Endothelial dysfunction correlates with decompression bubbles in rats

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    © 2016 The Author(s). Previous studies have documented that decompression led to endothelial dysfunction with controversial results. This study aimed to clarify the relationship between endothelial dysfunction, bubble formation and decompression rate. Rats were subjected to simulated air dives with one of four decompression rates: one slow and three rapid. Bubble formation was detected ultrasonically following decompression for two hours, before measurement of endothelial related indices. Bubbles were found in only rapid-decompressed rats and the amount correlated with decompression rate with significant variability. Serum levels of ET-1, 6-keto-PGF1a, ICAM-1, VCAM-1 and MDA, lung Wet/Dry weight ratio and histological score increased, serum NO decreased following rapid decompression. Endothelial-dependent vasodilatation to Ach was reduced in pulmonary artery rings among rapid-decompressed rats. Near all the above changes correlated significantly with bubble amounts. The results suggest that bubbles may be the causative agent of decompression-induced endothelial damage and bubble amount is of clinical significance in assessing decompression stress. Furthermore, serum levels of ET-1 and MDA may serve as sensitive biomarkers with the capacity to indicate endothelial dysfunction and decompression stress following dives

    Microbial Life in Supraglacial Environments

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    Supraglacial environments occupy 11% of Earth’s surface area and represent a critical interface between climate and ice. This century has brought a renewed appreciation that glacier surfaces represent a collective of diverse microbial niches which occur wherever sufficient liquid water is available to support microbial activity: even at the microscopic scales of ice crystal boundaries within the crystalline matrices of snow or glacial ice. Within this chapter, we review the range of microbial habitats associated with snowpacks, the glacial ice photic zone, and phototrophic microbial biofilms formed by supraglacial algae or by the darkening of microbe–mineral aggregates known as cryoconite. In summary, glacier surfaces are home to surprisingly biodiverse and active microbial communities despite their low temperatures and austere conditions. Consequently, microbial communities and their processes are interposed between climate and ice and merit urgent consideration in the light of the effects of climate warming on Earth’s supraglacial environments

    Genomics of psychrophilic bacteria and archaea

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    Genomes are available for a wide range of psychrophilic bacteria and archaea. As of early 2017, approximately 130 cold-adapted species have genome sequences. Several studies complement this data with functional studies. In this review the cold adaptation traits of psychrophilic microorganisms are explored from a genome-centric point of view including surveys of traits across genomes. A broader view of psychrophiles in terms of growth rates amongst life on Earth explaining what a psychrophile represents is presented. Trait surveys, limited to the perspective of gene gain, reveal prevalence of genes demonstratively providing better growth at low temperature including compatible solute uptake and synthesis, antifreeze proteins and polyunsaturated fatty acids and investigate their functional relevance to psychrophily. This includes revealing prevalent antifreeze DUF3494-type proteins that occur in all domains of life but is limited to cold-adapted taxa and is absent in higher-temperature adapted life
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