Extracellular vesicles are produced by many pathogenic microorganisms and have varied functions that include secretion and release of microbial factors, which contribute to virulence. Very little is ...known about vesicle production by Gram-positive bacteria, as well as their biogenesis and release mechanisms. In this work, we demonstrate the active production of vesicles by Streptococcus pneumoniae from the plasma membrane, rather than being a product from cell lysis. We biochemically characterized them by proteomics and fatty acid analysis, showing that these vesicles and the plasma membrane resemble in essential aspects, but have some differences: vesicles are more enriched in lipoproteins and short-chain fatty acids. We also demonstrate that these vesicles act as carriers of surface proteins and virulence factors. They are also highly immunoreactive against human sera and induce immune responses that protect against infection. Overall, this work provides insights into the biology of this important Gram-positive human pathogen and the role of extracellular vesicles in clinical applications.
Pneumococcus is one of the leading causes of bacterial pneumonia worldwide in children and the elderly, being responsible for high morbidity and mortality rates in developing countries. The augment of pneumococcal disease in developed countries has raised major public health concern, since the difficulties to treat these infections due to increasing antibiotic resistance. Vaccination is still the best way to combat pneumococcal infections. One of the mechanisms that bacterial pathogens use to combat the defense responses of invaded hosts is the production and release of extracellular vesicles derived from the outer surface. Little is known about this phenomenon in Gram-positives. We show that pneumococcus produces membrane-derived vesicles particularly enriched in lipoproteins. We also show the utility of pneumococcal vesicles as a new type of vaccine, as they induce protection in immunized mice against infection with a virulent strain. This work will contribute to understand the role of these structures in important biological processes such as host-pathogen interactions and prevention of human disease.
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•Pneumococcus produces membrane vesicles that are released to the milieu.•Proteomics show that they are more enriched in lipoproteins than the cell membrane.•Membrane vesicles induce protection against pneumococcal infection in mice.
Metal‐organic frameworks (MOFs) provide uniquely tunable, periodic platforms for site‐isolation of reactive low‐valent metal complexes of relevance in modern catalysis, adsorptive applications, and ...fundamental structural studies. Strategies for integrating such species in MOFs include post‐synthetic metalation, encapsulation and direct synthesis using low‐valent organometallic complexes as building blocks. These approaches have each proven effective in enhancing catalytic activity, modulating product distributions (i.e., by improving catalytic selectivity), and providing valuable mechanistic insights. In this minireview, we explore these different strategies, as applied to isolate low‐valent species within MOFs, with a particular focus on examples that leverage the unique crystallinity, permanent porosity and chemical mutability of MOFs to achieve deep structural insights that lead to new paradigms in the field of hybrid catalysis.
Matrix isolation of low‐valent complexes within metal–organic frameworks (MOFs) facilitates exceptional gas‐phase catalytic activity, stabilization of solution‐inaccessible catalysts, and fundamental insight into pertinent reaction mechanisms. MOFs present an ideal porous, crystalline, and chemically mutable matrix for such species. Herein we examine synthesis techniques and applications for the matrix isolation of low‐valent complexes within MOFs.
The effects of a paraffinic biofuel (farnesane) obtained from sugar cane, a gas to liquid (GTL) fuel, and a biodiesel fuel on performance and emissions of a light duty engine were evaluated. Similar ...engine performance is obtained with all fuels maintaining the default electronic control unit (ECU) configuration. Clear reductions in total hydrocarbon (THC) emissions were observed with all alternative fuels, and, comparing both paraffinic fuels, farnesane was more beneficial. Reductions were also obtained with these fuels in particle emissions, with the exception of the mode G, which is not an operating mode included in the New European Driving Cycle (NEDC), where particle number concentration of paraffinic fuels was higher compared with diesel and biodiesel fuels. This behavior could be explained by the nonoptimization of ECU at this engine work condition. The benefits in terms of pollutant emission obtained with farnesane make it a potential biofuel for use in diesel engines.
The neuroprotective effect of virgin olive oil (VOO) polyphenols has been related to their antioxidant effect. The main objective was to analyze how tyrosol and hydroxytyrosol contribute to the ...antioxidant and neuroprotective effects of VOO in a model of hypoxia–reoxygenation in rat brain slices. Rats were treated per os (po) (10 or 20 mg/kg/day) with hydroxytyrosol ethyl ether (HTEE), tyrosol ethyl ether (TEE), or 3,4-di-o-methylidene-hydroxytyrosol ethyl ether (MHTEE), used as a negative control for antioxidant effects. Lipid peroxidation was inhibited with HTEE, TEE, and MHTEE (from 5.0 ± 1.5 to 2.6 ± 1.5, 4.5 ± 1.5, and 4.8 ± 1.5 nmol/mg protein, respectively). However, all three compounds had similar neuroprotective effects: from 2.8 ± 0.07 to 1.8 ± 0.02 arbitrary units for HTEE, 1.4 ± 0.09 arbitrary units for TEE, and 1.3 ± 0.2 arbitrary units for MHTEE. All three compounds inhibited 3-nitrotyrosine production (from 3.7 ± 0.3 to 1.2 ± 0.03 nmol/0.1 g tissue for HTEE, 1.0 ± 0.2 nmol/0.1 g tissue for TEE, and 1.3 ± 0.1 nmol/0.1 g tissue for MHTEE), prostaglandin E2 production (from 55.7 ± 2.2 to 46.4 ± 1.9 pg/0.1 g tissue for HTEE, 24.7 ± 1.3 pg/0.1 g tissue for TEE, and 27.6 ± 2.6 pg/0.1 g tissue for MHTEE), whereas only HTEE inhibited IL1β production (from 35.7 ± 1.5 to 21.6 ± 0.8 pg/0.1 g tissue). Pearson correlation coefficients related neuroprotective effect with an antioxidant effect for HTEE (R = 0.72, p < 0.001), and inhibition of nitrosative stress (R = 0.78, 0.67, and 0.66 for HTEE, TEE, and MHTEE, respectively, p < 0.001) and inflammatory mediators (R = 0.72, 0.79, and 0.64 for HTEE, TEE, and MHTEE, respectively, p < 0.001) with all three compounds.
There are several specific solutions for accessing sensors and actuators present in any process or system through a TCP/IP network, either local or a wide area type like the Internet. The usage of ...sensors and actuators of different nature and diverse interfaces (SPI, I2C, analogue, etc.) makes access to them from a network in a homogeneous and secure way more complex. A framework, including both software and hardware resources, is necessary to simplify and unify networked access to these devices. In this paper, a set of open-source software tools, specifically designed to cover the different issues concerning the access to sensors and actuators, and two proposed low-cost hardware architectures to operate with the abovementioned software tools are presented. They allow integrated and easy access to local or remote sensors and actuators. The software tools, integrated in the free authoring tool Easy Java and Javascript Simulations (EJS) solve the interaction issues between the subsystem that integrates sensors and actuators into the network, called
in this paper, and the Human Machine Interface (HMI)-this one designed using the intuitive graphical system of EJS-located on the user's computer. The proposed hardware architectures and software tools are described and experimental implementations with the proposed tools are presented.
The problem of optimally sizing hybrid energy storage systems (HESS) installed in electric railway systems, considering the effect of regenerative braking is studied in this paper. HESSs combine ...traditional batteries and newly developed ultracapacitors, taking advantage of the high energy capacity of batteries and of the flexibility and ability to capture high power density of ultracapacitors. A novel mixed integer linear programming formulation that includes the counting of battery cycles is presented. Some particularities of battery operation are included in the model, like the dependence of its performance on the number of cycles and the depth of discharge (DOD). Results are reported first for a illustrative case study, allowing us to perform sensitivity studies for several parameters; results are also reported and for a larger case, closely resembling the problem faced by railway energy systems planners and operators.
Summary
Bacterial chemotaxis is an adaptive behaviour, which requires sophisticated information‐processing capabilities that cause motile bacteria to either move towards or flee from chemicals. ...Pseudomonas putida DOT‐T1E exhibits the capability to move towards different aromatic hydrocarbons present at a wide range of concentrations. The chemotactic response is mediated by the McpT chemoreceptor encoded by the pGRT1 megaplasmid. Two alleles of mcpT are borne on this plasmid and inactivation of either one led to loss of this chemotactic phenotype. Cloning of mcpT into a plasmid complemented not only the mcpT mutants but also its transfer to other Pseudomonas conferred chemotactic response to high concentrations of toluene and other chemicals. Therefore, the phenomenon of chemotaxis towards toxic compounds at high concentrations is gene‐dose dependent. In vitro experiments show that McpT is methylated by CheR and McpT net methylation was diminished in the presence of hydrocarbons, what influences chemotactic movement towards these chemicals.
The cultivation of short rotation coppice (SRC) is a sustainable and ecological alternative for the production of energy vectors today. For its use, it is necessary to know the thermochemical ...properties of the biomass produced, as well as the differences between genotypes and varieties. In this work, the thermochemical properties of five different Populus clones grow up in Mediterranean basin, with two different age categories, are analyzed. The moisture content, wood density, heating value, ash content, energy density, composition and the volatile matter were measured, separating wood and crust fractions. The mean crust content for all clones was near to 10% but it is observed that the youngest clones have higher content of crust and humidity. The 3 year-old clones generally show lower humidity and ash content and higher density of wood and fixed carbon, consequently showing a higher heating value. In addition, 3 year-old clones are encouraged since they have a lower content of majority and minority elements in proportion that can generate less operating and environmental problems.
The abandonment of traditional livestock farming systems in Mediterranean countries is triggering a large-scale habitat transformation, which, in general, consists of the replacement of open grazing ...areas by woodlands through non-managed regeneration. As a consequence, wild ungulates are occupying rapidly the empty niche left by domestic ungulates. Both types of ungulates represent the main trophic resource for large vertebrate scavengers. However, a comparison of how vertebrate scavengers consume ungulate carcasses in different habitats with different ungulate species composition is lacking. This knowledge is essential to forecast the possible consequences of the current farmland abandonment on scavenger species. Here, we compared the scavenging patterns of 24 wild and 24 domestic ungulate carcasses in a mountainous region of southern Spain monitored through camera trapping. Our results show that carcasses of domestic ungulates, which concentrate in large numbers in open pasturelands, were detected and consumed earlier than those of wild ungulate carcasses, which frequently occur in much lower densities at more heterogenous habitats such as shrublands and forest. Richness and abundance of scavengers were also higher at domestic ungulate carcasses in open habitats. Vultures, mainly griffons (Gyps fulvus), consumed most of the carcasses, although mammalian facultative scavengers, mainly wild boar (Sus scrofa) and red fox (Vulpes vulpes), also contributed importantly to the consumption of wild ungulate carcasses in areas with higher vegetation cover. Our findings evidence that the abandonment of traditional grazing may entail consequences for the scavenger community, which should be considered by ecologists and wildlife managers.
Metal-organic framework (MOF)-based catalysts are outstanding alternative materials for the chemical transformation of greenhouse and toxic gases into high-add-value products. MOF catalysts exhibit ...remarkable properties to host different active sites. The combination of catalytic properties of MOFs is mentioned in order to understand their application. Furthermore, the main catalytic reactions, which involve the chemical transformation of CH
4
, CO
2
, NO
x
, fluorinated gases, O
3
, CO, VOCs, and H
2
S, are highlighted. The main active centers and reaction conditions for these reactions are presented and discussed to understand the reaction mechanisms. Interestingly, implementing MOF materials as catalysts for toxic gas-phase reactions is a great opportunity to provide new alternatives to enhance the air quality of our planet.
The relevance of MOF materials as catalysts for the environmental remediation of toxic gases.
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