In this communication, a series of observations and data analyses coherently confirms the suitability of the novel metal-organic framework (MOF) ...Zn(4)(μ(4)-O)(μ(4)-4-carboxy-3,5-dimethyl-4-carboxy-pyrazolato)(3) (1) in the capture of harmful volatile organic compounds (VOCs). It is worthy of attention that 1, whose crystal structure resembles that of MOF-5, exhibits remarkable thermal, mechanical, and chemical stability, as required if practical applications are sought. In addition, it selectively captures harmful VOCs (including models of Sarin and mustard gas, which are chemical warfare agents), even in competition with ambient moisture (i.e., under conditions mimicking operative ones). The results can be rationalized on the basis of Henry constant and adsorption heat values for the different essayed adsorbates as well as H(2)O/VOC partition coefficients as obtained from variable-temperature reverse gas chromatography experiments. To further strengthen the importance of 1, its performance in the capture of harmful VOCs has been compared with those of well-known materials, namely, a MOF with coordinatively unsaturated metal sites, Cu(3)(btc)(2) and the molecular sieve active carbon Carboxen. The results of this comparison show that coordinatively unsaturated metal sites (preferential guest-binding sites) are ineffective for the capture of VOCs in the presence of ambient moisture. Consequently, we propose that the driving force of the VOC-MOF recognition process is mainly dictated by pore size and surface hydrophobicity.
The reaction of (cymene)RuCl(2)(2) with K(2)Hoxonate (H(3)oxonic = 4,6-dihydroxy-2-carboxy-1,3,5-triazine acid) in methanol leads to the formation of the dinuclear half-sandwich ruthenium(II) complex ...(cymene)(2)Ru(2)(mu-Hoxonato)Cl(2) (1a). Removal of the chloride ligands of 1a by treatment with AgCF(3)SO(3) yields (cymene)(2)Ru(2)(mu-Hoxonato)(CF(3)SO(3))(2) (1b), which, upon posterior reaction with N,N'-linkers (L = 4,4'-bipyridine (4,4'-bpy), 4,7-phenantroline (4,7-phen)), gives rise to the formation of the tetranuclear open boxes (cymene)(4)Ru(4)(mu-Hoxonato)(2)(mu-N,N'-L)(2)(CF(3)SO(3))(4) (2a, L = 4,4'-bpy; 2b, L = 4,7-phen). These systems have been characterized by (1)H NMR, UV-vis, and ESI-MS. The single-crystal structures of the dinuclear precursor 1a and of the clathrate 2b 4,7-phen have been determined. The interaction of these systems with cysteine, mononucleotides, and calf-thymus DNA has been studied by means of (1)H NMR, UV-vis, circular dicroism, competitive binding assays, and atomic force microscopy imaging. The results show that the robust tetracationic ruthenium(II) cyclic systems 2a and 2b do not give ligand exchange reactions toward biorelevant ligands. Nevertheless, these systems are able to noncovalently bind to DNA, probably at the surface of the major groove, inducing significant conformational changes in this biomolecule. It is also interesting to note that compounds 2a and 2b, in spite of only giving supramolecular interactions with biomolecules, exhibit antitumor activity, particularly toward the human ovarian cancer cell line A2780cisR, showing acquired resistance to cisplatin, with respective 4.6 and 8.3 microM IC(50) values.
Extracellular vesicles (EVs) are small lipid vesicles released by either any prokaryotic or eukaryotic cell, or both, with a biological role in cell-to-cell communication. In this work, we ...characterize the proteomes and nanomechanical properties of EVs released by tissue-culture cell-derived trypomastigotes (mammalian infective stage; (TCT)) and epimastigotes (insect stage; (E)) of Trypanosoma cruzi, the etiologic agent of Chagas disease. EVs of each stage were isolated by differential centrifugation and analyzed using liquid chromatography with tandem mass spectrometry (LC-MS/MS), dynamic light scattering (DLS), nanoparticle tracking analysis (NTA), electron microscopy and atomic force microscopy (AFM). Measurements of zeta-potential were also included. Results show marked differences in the surface molecular cargos of EVs between both stages, with a noteworthy expansion of all groups of trans-sialidase proteins in trypomastigote’s EVs. In contrast, chromosomal locations of trans-sialidases of EVs of epimastigotes were dramatically reduced and restricted to subtelomeric regions, indicating a possible regulatable expression of these proteins between both stages of the parasite. Regarding mechanical properties, EVs of trypomastigotes showed higher adhesion compared to the EVs of epimastigotes. These findings demonstrate the remarkable surface remodeling throughout the life cycle of T. cruzi, which shapes the physicochemical composition of the extracellular vesicles and could have an impact in the ability of these vesicles to participate in cell communication in completely different niches of infection.
Trans-sialidases (TS) are important constitutive macromolecules of the secretome present on the surface of Trypanosoma cruzi (T. cruzi) that play a central role as a virulence factor in Chagas ...disease. These enzymes have been related to infectivity, escape from immune surveillance and pathogenesis exhibited by this protozoan parasite. In this work, atomic force microscopy (AFM)-based single molecule-force spectroscopy is implemented as a suitable technique for the detection and location of functional TS on the surface of extracellular vesicles (EVs) released by tissue-culture cell-derived trypomastigotes (Ex-TcT). For that purpose, AFM cantilevers with functionalized tips bearing the anti-TS monoclonal antibody mAb 39 as a sense biomolecule are engineered using a covalent chemical ligation based on vinyl sulfonate click chemistry; a reliable, simple and efficient methodology for the molecular recognition of TS using the antibody-antigen interaction. Measurements of the breakdown forces between anti-TS mAb 39 antibodies and EVs performed to elucidate adhesion and forces involved in the recognition events demonstrate that EVs isolated from tissue-culture cell-derived trypomastigotes of T. cruzi are enriched in TS. Additionally, a mapping of the TS binding sites with submicrometer-scale resolution is provided. This work represents the first AFM-based molecular recognition study of Ex-TcT using an antibody-tethered AFM probe.
The substitution of fish resources as ingredients for aquafeeds by those based on vegetable sources is needed to ensure aquaculture sustainability in the future. It is known that Senegalese sole ...(Solea senegalensis) accepts high dietary content of plant ingredients without altering growth or flesh quality parameters. However, scarce information is available regarding the long-term impact of vegetable diets (combining the inclusion of both vegetable protein and oils) on the stress response and immunity of this fish species. This study aims to evaluate the concomitant effect of the extended use of vegetable protein-based diets with fish oil (FO) replacement (0, 50 or 100%) by vegetable oils (VO), on the response to acute (10 min) or prolonged (4 days) stress, induced by thermal shock. Plasma levels of cortisol, glucose and lactate as well as hepatic levels of glucose, glycogen and lactate were evaluated as primary and secondary responses to stress, 6 and 18 months after feeding the experimental diets (6 and 18 MAF). The brain monoaminergic activity in telencephalon and hypothalamus, and non-specific immune parameters were also evaluated. As expected, thermal shock induced an increase in values of plasma parameters related to stress, which was more evident in acute than in prolonged stress. Stress also affected lactate levels in the liver and the values of the alternative complement pathway-ACH50 in the plasma. Dietary substitution of FO induced an effect per se on some parameters such as decreased hepatic glucose and glycogen levels and peroxidase activity in plasma as well enhanced serotonergic activity in brain of non-stressed fish. The results obtained in some parameters indicate that there is an interaction between the use of vegetable diets with the physiological response to thermal stress, as is the case of the hepatic lactate, serotonergic neurotransmission in brain, and the activity of ACH50 in plasma. These results suggest that the inclusion of VO in plant protein based diets point to a slightly inhibited stress response, more evident for an acute than a prolonged stress.
The vesicular microstructure is a very distinctive arrangement of calcite, consisting of hollow cavities (vesicles) of diverse sizes and shapes, usually elongated in the direction of shell ...thickening. It is uniquely found among living bivalves in a single oyster family, Gryphaeidae. The vesicles are distributed in lenses interleaved with compact foliated layers. We have studied the morphology and distribution of vesicles within the lenses using optical and electron microscopy, and micro-computed tomography. At a small scale, vesicles do not follow a classical von Neumann-Mullins route typical of ideal foams. At a larger scale, the initiation and evolution of a vesicular layer statistically proceed like a foam, with vesicles becoming more numerous, larger and more even in size. In summary, the vesicular material follows a foam-like coarsening to reduce the number of energetically costly interfaces. However, a steady state is never reached because the animal permanently introduces energy in the system by creating new vesicles. The fabrication of the vesicular material is mediated by the production of an emulsion between the extrapallial fluid and the precursor PILP of the calcitic walls within the thin extrapallial space. For this mechanism to proceed, the mantle cells must perform highly sophisticated behaviours of contact recognition and secretion. Accordingly, the vesicular material is under mixed physical-biological control.
Temperature matters! The separation efficiency of complex mixtures of gases (acetylene, carbon dioxide, methane, nitrogen) and vapors (benzene, cyclohexane) by adsorption on ...ACu3(μ3‐OH)(μ3‐4‐carboxypyrazolato)3 (A@1) metal–organic frameworks depends on temperature and the extraframework cation A (see picture). NH4@1 also behaves as an oxidation catalyst.
DNA molecules containing a 1D silver array may be applied for nanotechnology applications, but first their conducting and photoluminescence behavior must be enhanced. Here we have synthesized and ...characterized three new helical compounds based on stacked silver-mediated cytosine base pairs Ag(mC)
X (mC = N1-methylcytosine; X = NO
(
), BF
(
) and ClO
(
)), that contain uninterrupted polymeric Ag
chains that run through the center of the helixes, comparable to related silver-DNA structures. The exposure of nanostructures of Ag(mC)
BF
(
) to cold hydrogen plasma stimulates the reduction of the prearranged Ag
polymeric chains to metallic silver along the material. This solvent-free reduction strategy leads to the compound Ag
(mC)
X@Ag
(
) that contains uniformly well-distributed silver metallic nanostructures that are responsible for the new conducting and photoluminescence properties of the material. The presence of silver nanostructures alongside compound
has been evaluated by means of X-ray photoelectron spectroscopy (XPS), UV-vis spectroscopy, and X-ray powder diffraction (XRPD). The conducting and photoactive properties of
were studied by electrostatic force microscopy (EFM) and conducting-AFM (c-AFM), and photoluminescence microscopy (PL), respectively. The results demonstrate that the presence of well-organized metallic silver nanoentities on the material is responsible for the novel conductivity and photoactive properties of the material. This methodology can be employed for the generation of multifunctional silver-DNA related materials with tailored properties.
Sustainable aquaculture is highly dependent on the optimization of aquafeeds in terms of production costs, environmental sustainability and nutritional value. Senegalese sole (Solea senegalensis) is ...a prized flatfish produced in Europe with demonstrated capacity to cope well with both vegetable protein and oil sources. However, the total replacement of fish oil (FO) in diets with a high inclusion of plant proteins (PP) has never been assessed before in this species. Three extruded isoenergetic (23 KJ/g) and isolipidic (15% DM) practical PP-based diets (75% PP) were formulated: a control diet with fish oil (FO) and two experimental diets with 50% and 100% inclusion of a vegetable oil (VO) blend to replace FO (VO50 and VO100). Triplicate groups of fish (13.3 ± 0.9 g) were kept in a recirculation saltwater system at 19 °C and fed the experimental diets ad libitum during 18 months. Fish were sampled after 6 and 18 months (in juvenile and on-growing developmental stages, respectively). The total substitution of FO by VO (VO100) during the juvenile phase (6 months of feeding) significantly reduced final body weight, daily growth index, and protein gain, and increased FCR. A longer feeding period (after 18 months) showed that VO inclusion had no major effects on fish growth, but FCR was still significantly higher in fish fed VO100 than in FO. At the end of the trial, muscle saturated FA level decreased with increasing dietary VO, whereas monounsaturated and polyunsaturated FA levels increased in fish fed VO diets particularly due to increased levels of linoleic, α-linoleic and arachidonic acid acids. In conclusion, the long-term replacement of marine ingredients by VO and PP sources does not impair Senegalese sole growth, but strongly reduces EPA + DHA muscle levels, compromising the nutritional value of fillets for human consumption.
•Total substitution of fish oil (FO) by vegetable oil (VO) in plant protein-rich diets (PP) during the juvenile phase significantly reduces growth•The long-term replacement of FO does not impair fish growth or nutrient gain•FCR increases with VO dietary inclusion, being significantly higher in PP100 diets compared to those fed FO•VO inclusion increased PUFA levels and decreased MUFA and SFA in both muscle and liver•VO inclusion strongly reduces EPA + DHA muscle levels, compromising the nutritional value of fillets for human consumption
The shell of the cephalopod Argonauta consists of two layers of fibers that elongate perpendicular to the shell surfaces. Fibers have a high-Mg calcitic core sheathed by thin organic membranes ...(>100 nm) and configurate a polygonal network in cross section. Their evolution has been studied by serial sectioning with electron microscopy-associated techniques. During growth, fibers with small cross-sectional areas shrink, whereas those with large sections widen. It is proposed that fibers evolve as an emulsion between the fluid precursors of both the mineral and organic phases. When polygons reach big cross-sectional areas, they become subdivided by new membranes. To explain both the continuation of the pattern and the subdivision process, the living cells from the mineralizing tissue must perform contact recognition of the previously formed pattern and subsequent secretion at sub-micron scale. Accordingly, the fabrication of the argonaut shell proceeds by physical self-organization together with direct cellular activity.
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•The shell consists of a polygonal organic pattern that evolves as a physical system•An emulsion model accounts for the configuration of the pattern•Mean polygon size and number is kept by the additional splitting of large polygons•Cell sensitivity explains the propagation of the pattern and polygon splitting
Cell engineering; Biomaterials; Materials characterization; Microstructure
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