Search results for "Respiratory physiology"
showing 10 items of 363 documents
Deciphering carbon sources of mussel shell carbonate under experimental ocean acidification and warming.
2018
Abstract Ocean acidification and warming is widely reported to affect the ability of marine bivalves to calcify, but little is known about the underlying mechanisms. In particular, the response of their calcifying fluid carbonate chemistry to changing seawater carbonate chemistry remains poorly understood. The present study deciphers sources of the dissolved inorganic carbon (DIC) in the calcifying fluid of the blue mussel (Mytilus edulis) reared at two pH (8.1 and 7.7) and temperature (16 and 22 °C) levels for five weeks. Stable carbon isotopic ratios of seawater DIC, mussel soft tissues and shells were measured to determine the relative contribution of seawater DIC and metabolically gener…
Lung function assessment in the Pacific walrus (Odobenus rosmarus divergens) while resting on land and submerged in water
2020
In the present study, we examined lung function in healthy resting adult (born in 2003) Pacific walruses (Odobenus rosmarus divergens) by measuring respiratory flow ([Formula: see text]) using a custom-made pneumotachometer. Three female walruses (670-1025 kg) voluntarily participated in spirometry trials while spontaneously breathing on land (sitting and lying down in sternal recumbency) and floating in water. While sitting, two walruses performed active respiratory efforts, and one animal participated in lung compliance measurements. For spontaneous breaths, [Formula: see text] was lower when walruses were lying down (e.g. expiration: 7.1±1.2 l s-1) as compared with in water (9.9±1.4 l s-…
Whistling is metabolically cheap for communicating bottlenose dolphins (Tursiops truncatus)
2020
Toothed whales depend on sound for communication and foraging, making them potentially vulnerable to acoustic masking from increasing anthropogenic noise. Masking effects may be ameliorated by higher amplitudes or rates of calling, but such acoustic compensation mechanisms may incur energetic costs if sound production is expensive. The costs of whistling in bottlenose dolphins (Tursiops truncatus) have been reported to be much higher (20-50% of resting metabolic rate, RMR) than theoretical predictions (0.5-1% of RMR). Here we address this dichotomy by measuring the change in the resting O2 consumption rate (V̇O2), a proxy for RMR, in three post-absorptive bottlenose dolphins during whistlin…
Biological and physical modification of carbonate system parameters along the salinity gradient in shallow hypersaline solar salterns in Trapani, Ita…
2017
Abstract We investigated changes in the chemical characteristics of evaporating seawater under the influence of microbial activity by conducting geochemical analyses of the brines and evaporite sediments collected from solar salterns in Trapani, Italy. The microbial activity had a substantial effect on the carbonate system parameters. Dissolved inorganic carbon (DIC) was substantially removed from the brine during the course of evaporation from the seawater to the point where calcium carbonate precipitates, with an accompanying decrease in its carbon isotopic composition (δ 13 C DIC ) to as low as −10.6‰. Although the removal of DIC was due to calcium carbonate precipitation, photosynthesis…
Structural characterization of polysaccharides of a productive strain of the culinary-medicinal king oyster mushroom, pleurotus eryngii (Agaricomycet…
2018
A preliminary biological investigation of the dry basidiomata of strain C-142-c of Pleurotus eryngii has shown significant antioxidant activity. Two different polysaccharides (PEPS-A1 and PEPS-A2) were isolated from the cultivated edible mushroom, P. eryngii C-142-c strain. Based on acid hydrolysis, methylation analysis, and nuclear magnetic resonance experiments (1H, 13C, distortionless enhancement by polarization transfer, double quantum filtered correlation spectroscopy, total correlation spectroscopy, nuclear Overhauser effect spectroscopy, heteronuclear singlequantum correlation spectroscopy, and heteronuclear multiple-bond correlation spectroscopy), the structures of the repeating uni…
CD36-fibrin interaction propagates FXI-dependent thrombin generation of human platelets.
2019
Thrombin converts fibrinogen to fibrin and activates blood and vascular cells in thrombo-inflammatory diseases. Platelets are amplifiers of thrombin formation when activated by leukocyte- and vascular cell-derived thrombin. CD36 on platelets acts as sensitizer for molecules with damage-associated molecular patterns, thereby increasing platelet reactivity. Here, we investigated the role of CD36 in thrombin-generation on human platelets, including selected patients with advanced chronic kidney disease (CKD). Platelets deficient in CD36 or blocked by anti-CD36 antibody FA6.152 showed impaired thrombin generation triggered by thrombin in calibrated automated thrombography. Using platelets with …
Gut microbiota regulate hepatic von Willebrand factor synthesis and arterial thrombus formation via Toll-like receptor-2.
2016
The symbiotic gut microbiota play pivotal roles in host physiology and the development of cardiovascular diseases, but the microbiota-triggered pattern recognition signaling mechanisms that impact thrombosis are poorly defined. In this article, we show that germ-free (GF) and Toll-like receptor-2 (Tlr2)-deficient mice have reduced thrombus growth after carotid artery injury relative to conventionally raised controls. GF Tlr2-/- and wild-type (WT) mice were indistinguishable, but colonization with microbiota restored a significant difference in thrombus growth between the genotypes. We identify reduced plasma levels of von Willebrand factor (VWF) and reduced VWF synthesis, specifically in he…
Validation of ADAM10 metalloprotease as aBacillus thuringiensisCry3Aa toxin functional receptor in Colorado potato beetle (Leptinotarsa decemlineata)
2016
Bacillus thuringiensis parasporal crystal proteins (Cry proteins) are insecticidal pore-forming toxins that bind to specific receptor molecules on the brush border membrane of susceptible insect midgut cells to exert their toxic action. In the Colorado potato beetle (CPB), a coleopteran pest, we previously proposed that interaction of Cry3Aa toxin with a CPB ADAM10 metalloprotease is an essential part of the mode of action of this toxin. Here, we annotated the gene sequence encoding an ADAM10 metalloprotease protein (CPB-ADAM10) in the CPB genome sequencing project, and using RNA interference gene silencing we demonstrated that CPB-ADAM10 is a Cry3Aa toxin functional receptor in CPB. Cry3Aa…
Microparticles harbouring Sonic hedgehog morphogen improve the vasculogenesis capacity of endothelial progenitor cells derived from myocardial infarc…
2019
Aims Endothelial progenitor cells (EPC) play a role in endothelium integrity maintenance and regeneration. Decreased numbers of EPC or their impaired function correlates with an increase in cardiovascular events. Thus, EPC are important predictors of cardiovascular mortality and morbidity. Microparticles carrying Sonic hedgehog (Shh) morphogen (MPShh+) trigger pro-angiogenic responses, both in endothelial cells and in ischaemic rodent models. Here, we propose that MPShh+ regulates EPC function, thus enhancing vasculogenesis, and correcting the defects in dysfunctional EPC obtained from acute myocardial infarction (AMI) patients. Methods and results The mechanisms underlying Shh pathway func…
7-Keto-Cholesterol and Cholestan-3beta, 5alpha, 6beta-Triol Induce Eryptosis through Distinct Pathways Leading to NADPH Oxidase and Nitric Oxide Synt…
2019
Background/aims We showed that patho-physiological concentrations of either 7-keto-cholesterol (7-KC), or cholestane-3beta, 5alpha, 6beta-triol (TRIOL) caused the eryptotic death of human red blood cells (RBC), strictly dependent on the early production of reactive oxygen species (ROS). The goal of the current study was to assess the contribution of the erythrocyte ROS-generating enzymes, NADPH oxidase (RBC-NOX), nitric oxide synthase (RBC-NOS) and xanthine oxido-reductase (XOR) to the oxysterol-dependent eryptosis and pertinent activation pathways. Methods Phosphatidylserine exposure at the cell surface was estimated from annexin-V-binding, reactive oxygen/nitrogen species (RONS) and nitri…