Identification of IPT9 in Brachiaria brizantha (syn. Urochloa brizantha) and expression analyses during ovule development in sexual and apomictic plants.

BACKGROUND: In Brachiaria sexual reproduction, during ovule development, a nucellar cell differentiates into a megaspore mother cell (MMC) that, through meiosis and mitosis, gives rise to a reduced embryo sac. In aposporic apomictic Brachiaria, next to the MMC, other nucellar cells differentiate into aposporic initials that enter mitosis directly forming an unreduced embryo sac. The IPT (isopentenyltransferase) family comprises key genes in the cytokinin (CK) pathway which are expressed in Arabidopsis during ovule development. BbrizIPT9, a B. brizantha (syn. Urochloa brizantha) IPT9 gene, highly similar to genes of other Poaceae plants, also shows similarity with Arabidopsis IPT9, AtIPT9. In this work, we aimed to investigate association of BbrizIPT9 with ovule development in sexual and apomictic plants. METHODS AND RESULTS: RT-qPCR showed higher BbrizIPT9 expression in the ovaries of sexual than in the apomictic B. brizantha. Results of in-situ hybridization showed strong signal of BbrizIPT9 in the MMC of both plants, at the onset of megasporogenesis. By analyzing AtIPT9 knockdown mutants, we verified enlarged nucellar cell, next to the MMC, in a percentage significantly higher than in the wild type, suggesting that knockout of AtIPT9 gene triggered the differentiation of extra MMC-like cells. CONCLUSIONS: Our results indicate that AtIPT9 might be involved in the proper differentiation of a single MMC during ovule development. The expression of a BbrizIPT9, localized in male and female sporocytes, and lower in apomicts than in sexuals, and effect of IPT9 knockout in Arabidopsis, suggest involvement of IPT9 in early ovule development.

A role for hepcidin in the anemia caused by Trypanosoma brucei infection.

Trypanosomiasis is a parasitic disease affecting both humans and animals in the form of Human African Trypanosomiasis and Nagana disease, respectively. Anemia is one of the most common symptoms of trypanosomiasis, and if left unchecked can cause severe complications and even death. Several factors have been associated with the development of this anemia, including dysregulation of iron homeostasis, but little is known about the molecular mechanisms involved. Here, using murine models, we study the involvement of hepcidin, the key regulator of iron metabolism and an important player in the development of anemia of inflammation. Our data show two stages for the progression of anemia, to which hepcidin contributes a first stage when anemia develops, with a likely cytokine-mediated stimulation of hepcidin and subsequent limitation in iron availability and erythropoiesis, and a second stage of recovery, where the increase in hepcidin then declines due to the reduced inflammatory signal and increased production of erythroid regulators by the kidney, spleen and bone marrow, thus leading to an increase in iron release and availability, and enhanced erythropoiesis. In agreement with this, in hepcidin knockout mice, anemia is much milder and its recovery is complete, in contrast to wild-type animals which have not fully recovered from anemia after 21 days. Besides all other factors known to be involved in the development of anemia during trypanosomiasis, hepcidin clearly makes an important contribution to both its development and recovery.

Histology, histochemistry and ultrastructure of pre-embryogenic cells determined for direct somatic embryogenesis in the palm tree Syagrus oleracea.

Somatic embryogenesis in palm trees is, in general, a slow and highly complex process, with a predominance of the indirect route and, consequently, a lack of knowledge about the direct route. We present new knowledge related to the morphological, histochemical and ultrastructural aspects of the transition from somatic to embryogenic cells and direct formation of somatic embryos from mature zygotic embryos of Syagrus oleracea, a palm tree. The results support the general concept that 2,4-dichlorophenoxyacetic acid plays a critical role for the formation of somatic embryos of direct and multicellular origin. Seven days in medium with auxin were enough for the identification of embryogenic cells. These cells had a set of characteristics corresponding to totipotent stem cells. At 14 days on induction medium, nodular formations were observed in the distal region of inoculated embryos, which evolved into globular somatic embryos. At 120 days on induction medium, the quality of the somatic embryos was compromised. The dynamics of the mobilization of reserve compounds was also demonstrated, with emphasis on starch and protein as energy sources required for the embryogenic process. This study shows for the first time the anatomical and ultrastructural events involved in direct somatic embryogenesis in a palm tree and incites the scientific community to return to the discussion of classical concepts related to direct somatic embryogenesis, especially regarding the characteristics and location of determined pre-embryogenic cells.

Interactions and Supramolecular Organization of Sulfonated Indigo and Thioindigo Dyes in Layered Hydroxide Hosts.

Supramolecularly organized host-guest systems have been synthesized by intercalating water-soluble forms of indigo (indigo carmine, IC) and thioindigo (thioindigo-5,5'-disulfonate, TIS) in zinc-aluminum-layered double hydroxides (LDHs) and zinc-layered hydroxide salts (LHSs) by coprecipitation routes. The colors of the isolated powders were dark blue for hybrids containing only IC, purplish blue or dark lilac for cointercalated samples containing both dyes, and ruby/wine for hybrids containing only TIS. The as-synthesized and thermally treated materials were characterized by Fourier transform infrared, Fourier transform Raman, and nuclear magnetic resonance spectroscopies, powder X-ray diffraction, scanning electron microscopy, and elemental and thermogravimetric analyses. The basal spacings found for IC-LDH, TIS-LDH, IC-LHS, and TIS-LHS materials were 21.9, 21.05, 18.95, and 21.00 Å, respectively, with intermediate spacings being observed for the cointercalated samples that either decreased (LDHs) or increased (LHSs) with increasing TIS content. UV-visible and fluorescence spectroscopies (steady-state and time-resolved) were used to probe the molecular distribution of the immobilized dyes. The presence of aggregates together with the monomer units is suggested for IC-LDH, whereas for TIS-LDH, IC-LHS, and TIS-LHS, the dyes are closer to the isolated situation. Accordingly, while emission from the powder H2TIS is strongly quenched, an increment in the emission of about 1 order of magnitude was observed for the TIS-LDH/LHS hybrids. Double-exponential fluorescence decays were obtained and associated with two monomer species interacting differently with cointercalated water molecules. The incorporation of both TIS and IC in the LDH and LHS hosts leads to an almost complete quenching of the fluorescence, pointing to a very efficient energy transfer process from (fluorescent) TIS to (nonfluorescent) IC.

A Comparative Study of Molybdenum Carbonyl and Oxomolybdenum Derivatives Bearing 1,2,3-Triazole or 1,2,4-Triazoles in Catalytic Olefin Epoxidation.

The molybdenum(0)-carbonyl-triazole complexes [Mo(CO)3(L)3] [L = 1,2,3-triazole (1,2,3-trz) or 1,2,4-triazole (1,2,4-trz)] have been prepared and examined as precursors to molybdenum(VI) oxide catalysts for the epoxidation of cis-cyclooctene. Reaction of the carbonyl complexes with the oxidant tert-butyl hydroperoxide (TBHP) (either separately or in situ) gives oxomolybdenum(VI) hybrid materials that are proposed to possess one-dimensional polymeric structures in which adjacent oxo-bridged dioxomolybdenum(VI) moieties are further linked by bidentate bridging triazole (trz) ligands. A pronounced ligand influence on catalytic performance was found and the best result (quantitative epoxide yield within 1 h at 70 °C) was obtained with the 1,2,3-triazole oxomolybdenum(VI) hybrid. Both molybdenum oxide-triazole compounds displayed superior catalytic performance in comparison with the known hybrid materials [MoO3(trz)0.5], which have different structures based on organic-inorganic perovskite-like layers. With aqueous H2O2 as the oxidant instead of TBHP, all compounds were completely soluble and active. A pronounced ligand influence on catalytic performance was only found for the hybrids [MoO3(trz)0.5], and only the 1,2,4-trz compound displayed reaction-induced self-precipitation behavior. An insight into the type of solution species that may be involved in the catalytic processes with these compounds was obtained by separately treating [MoO3(1,2,4-trz)0.5] with excess H2O2, which led to the crystallization of the complex (NH4)1.8(H3O)0.2[Mo2O2(µ2-O)(O2)4(1,2,4-trz)]·H2O. The single-crystal X-ray investigation of this complex reveals an oxo-bridged dinuclear structure with oxodiperoxo groups being further linked by a single triazole bridge.

Insights into the Photophysics and Supramolecular Organization of Congo Red in Solution and the Solid State.

Steady-state and time-resolved absorption and fluorescence measurements are reported for Congo Red (CR) in aqueous and dimethylsulfoxide (DMSO) solutions. The very low fluorescence quantum yield (≈10-4 ) for CR in dilute solutions together with the absence of a triplet state indicates that internal conversion is the dominant deactivation route with more than 99.99 % of the quanta loss (attributed to the energy gap law for radiationless transitions). Although no direct evidence for trans-cis photoisomerization was obtained from absorption or fluorescence data, the global analysis of fs-transient absorption data indicates the presence of a photoproduct with a lifetime of ≈170 ps that is suggested to be associated with such a process. Spectral data for more concentrated CR solutions indicate the presence of oblique or twisted J-type aggregates. These results are compared with spectra for CR in the solid state (sodium salt) and intercalated in a layered double hydroxide via a one-step co-precipitation route. Powder XRD and electronic spectral data for the nanohybrid indicate that the CR guest molecules are intercalated as a monolayer consisting of slipped cofacial J-type aggregates.

Ferrocene and ferrocenium inclusion compounds with cucurbiturils: a study of metal atom dynamics probed by Mössbauer spectroscopy.

Temperature-dependent 57Fe Mössbauer effect (ME) spectroscopic studies were carried out on ferrocene (Fc), 1,1'-dimethylferrocene (1,1'(CH3)2Fc) and ferrocenium hexafluorophosphate (FcPF6) guest species in cucurbit[n]uril (n = 7, 8) inclusion complexes. The solid inclusion complexes were isolated by freeze-drying of dilute aqueous solutions and/or microwave-assisted precipitation from concentrated mixtures. The presence of genuine 1 : 1 (host : guest) inclusion complexes in the isolated solids was supported by liquid-state 1H and solid-state 13C{1H} MAS NMR, elemental and thermogravimetric analyses, powder X-ray diffraction, FTIR spectroscopy, and diffuse reflectance UV-Vis spectroscopy. The ME spectra of the complexes CB7·Fc and CB7·1,1'(CH3)2Fc consist of well-resolved doublets with hyperfine parameters (isomer shift and quadrupole splitting at 90 K) and temperature-dependent recoil-free fraction data that are very similar to those for the neat parent compounds, Fc and 1,1'(CH3)2Fc, suggesting that the organometallic guest molecules do not interact significantly with the host environment over the experimental temperature range. The ME spectra for CB7·FcPF6 and CB8·FcPF6 consist of a major broad line resonance attributed to a paramagnetic FeIII site. From the temperature-dependence of the recoil-free fraction it is evident that the charged guest species in these systems interact with the host environment significantly more strongly than was observed in the case of the neutral guest species, Fc and 1,1'(CH3)2Fc. Moreover, the ME data indicate that the vibrational amplitude of the ferrocenium guest molecule is significantly larger in the CB8 host molecule than in the CB7 homologue, as expected on the basis of the different cavity sizes.

Labelling of electronic cigarettes: regulations and current practice.

BACKGROUND: Over the past decade e-cigarettes have established themselves in the global market. E-cigarettes triggered much interest in relation to their content and efficacy as smoking cessation tools, but less attention has been paid to users and environmental safety warnings and guidance. Several regulations have been introduced to promote their safe handling and disposal. From May 2016, liquids and cartridges will be regulated by European Community Directives (ECDs) 2001/83/EC and 93/42/EEC, or 2014/40/EU if marketed as tobacco-related products. Currently, manufacturers and distributors must abide by the Chemical (Hazard Information and Packaging for Supply) Regulations 2009 (CHIP) or Classification, Labelling and Packaging Regulations (CLP), the latter replacing CHIP in June 2015. OBJECTIVE: In this work, the compliance of marketed e-liquids and e-cigarettes with current European Union and UK legislations is assessed. RESULTS: E-liquids and e-cigarettes (21 and 9 brands, respectively) were evaluated. Evidence of non-compliance was found in relation to the CHIP/CLP toxic (13%) and environmental (37%) pictograms, tactile warning (23%), nominal amount of solution (30%), supplier contact telephone number and address (40%). None of the evaluated e-cigarettes displayed information on the correct disposal/recycling of batteries in line with the ECD 2006/66/EC. CONCLUSIONS: More stringent enforcement of regulations is needed to ensure not only the user's safety and awareness, but also the safeguarding of the environment.

Catalytic alcoholysis of epoxides using metal-free cucurbituril-based solids.

Metal-free cucurbit[7]uril (CB7) solid-state assemblies promote acid-catalysed alcoholysis of aliphatic and aromatic epoxides under mild conditions to give ß-alkoxy alcohols, which are important intermediates for the synthesis of a vast range of compounds such as bioactive pharmaceuticals. The catalytic process is heterogeneous and the catalyst can be reused in consecutive runs without any reactivation treatment. The acid species responsible for the catalytic activity of CB7 may be entrapped hydronium ions.

An Indigo Carmine-Based Hybrid Nanocomposite with Supramolecular Control of Dye Aggregation and Photobehavior.

Zn-Al layered double hydroxides (LDHs) containing solely indigo carmine (IC) or 1-hexanesulfonate (HS) anions, or a mixture of the two with different HS/IC molar ratios, were prepared by the direct synthesis method and characterized by various techniques. Hydrotalcite-type phases were obtained with basal spacings of 17.6 Šfor the LDH intercalated by IC (IC-LDH) and 18.2-18.3 Šfor the other materials containing HS. From the basal spacing for IC-LDH and UV/Vis spectroscopic data, it is proposed that the dye molecules assemble within the interlayer galleries to form a J-type stacking arrangement. A comprehensive electronic spectral and photophysical study was undertaken for IC in solution and all materials, aiming to obtain a detailed characterization of the host-guest and guest-guest interactions. In solution (the solvent surrounded "isolated" molecule), IC presents a fast excited state proton transfer with rate constants of ∼1.2-1.4×10(11)  s(-1) , which is linked to the very efficient radiationless deactivation channel. In the solid state it is shown that incorporation of IC within the LDH decreases the level of aggregation, and that further addition of HS induces the appearance of isolated IC units within the LDH galleries. The indigo carmine-based nanocomposites reported constitute a step forward in the design of hybrid materials with tunable properties.

Controlling the fluorescence behavior of 1-pyrenesulfonate by cointercalation with a surfactant in a layered double hydroxide.

Zn-Al layered double hydroxides (LDHs) containing solely 1-pyrenesulfonate (PS) or 1-heptanesulfonate (HS) anions, or a mixture of the two with HS/PS molar ratios ranging between ca. 7.5 and 82, were prepared by the direct synthesis method and characterized by powder X-ray diffraction, thermal and elemental analyses, scanning electron microscopy, and FT-IR, FT-Raman, and (13)C{(1)H} CP MAS NMR spectroscopies. Well-ordered intercalates were obtained with basal spacings of 18.8 Šfor the LDH intercalated by PS and 19.2-19.4 Šfor the other materials containing HS. The photophysics of the solids, as well as the PS probe dissolved in water and common organic solvents (aiming to compare the behavior of the "isolated" molecule with that in the solid), were investigated by steady-state and time-resolved fluorescence techniques. The fluorescence spectra of the solid samples display two bands with maxima at 376 and 495 nm. Depending on the HS/PS ratios, the band intensity ratio (obtained at 375 and 520 nm) changes, reflecting different contributions from monomer and dimer species. The decays collected at 375 nm are biexponentials with a major component (∼97% of the total fluorescence) of 105 ns for the highest HS/PS ratio, which further loses importance with an increase in the PS content. When the decays are collected at 480 and 520 nm, the fits are triexponentials with a major component varying from 108 to 124 ns, attributed to an excimer. Steady-state and time-resolved measurements with PS in solution (ethanol, methanol, DMF, DMSO, and water) were also measured, and a comparison of the vibronic I1/I3 ratio and lifetimes in water (65 ns) with those in the LDHs indicates that the PS probe in the cointercalated LDHs is surrounded by the HS surfactant.

The Multi-Resistant Reaction of Drought-Tolerant Coffee 'Conilon Clone 14' to Meloidogyne spp. and Late Hypersensitive-Like Response in Coffea canephora.

Root-knot nematodes (RKN), Meloidogyne spp., have major economic impact on coffee production in Central and South America. Genetic control of RKN constitutes an essential part for integrated pest management strategy. The objective of this study was to evaluate the resistance of Coffea canephora genotypes (clones) to Meloidogyne spp. Sensitive and drought-tolerant coffee genotypes were used to infer their resistance using nematode reproduction factor and histopathology. Eight clonal genotypes were highly resistant to M. paranaensis. 'Clone 14' (drought-tolerant) and 'ESN2010-04' were the only genotypes highly resistant and moderately resistant, respectively, to both M. incognita races 3 and 1. Several clones were highly resistant to both avirulent and virulent M. exigua. Clone 14 and ESN2010-04 showed multiple resistance to major RKNs tested. Roots of 'clone 14' (resistant) and 'clone 22' (susceptible) were histologically studied against infection by M. incognita race 3 and M. paranaensis. Reduction of juvenile (J2) penetration in clone 14 was first seen at 2 to 6 days after inoculation (DAI). Apparent early hypersensitive reaction (HR) was seen in root cortex between 4 and 6 DAI, which led to cell death and prevention of some nematode development. At 12 to 20 DAI, giant cells formed in the vascular cylinder, besides normal development into J3/J4. From 32 to 45 DAI, giant cells were completely degenerated. Late, intense HR and cell death were frequently observed around young females and giant cells reported for the first time in coffee pathosystem. These results provide rational bases for future studies, including prospection, characterization, and expression profiling of genomic loci involved in both drought tolerance and resistance to multiple RKN species.

Concomitant unipolar radiofrequency ablation of nonparoxysmal atrial fibrillation in rheumatic and degenerative valve disease.

OBJECTIVES: The aim of this study was to compare the results of concomitant unipolar radiofrequency ablation of nonparoxysmal atrial fibrillation (AF) between rheumatic and degenerative valve disease (RHD versus DVD). METHODS: Between 2005 and 2012, 96 patients underwent AF ablation with unipolar radiofrequency concurrently with heart valve surgery. They were followed in three months and at a median follow-up of 39 (18 to 61) months. RESULTS: The mean age was 62 years old. Most patients had RHD (54.2%) and dilated left atria (LA, diameter 52.6 ± 5.8 mm). Patients with RHD were more likely to be younger and have larger LA. 88 patients (92%) underwent prophylactic closure of the left atrial appendage (LAA). Pulmonary vein-isolation, box lesion, LAA isolation, and left isthmus line were performed by radiofrequency, along with other right atrial cut-and-sew lines. Overall, surgical complications occurred in 25% of the patients and pacemaker implantation (17.7%) was the most frequently observed. In-hospital mortality rate was zero. The median length of stay was 8 (7, 12) days. Seventy-one percent of the patients were in sinus rhythm at discharge. Sinus rhythm maintenance was 45% and 40% in three months and at a median follow-up of 39 (18 to 61) months (269 patient-years), respectively. There was no statistically significant difference between RHD and DVD. In the multivariate analysis, LA ≥50 mm was the single independent predictor of AF recurrence at three months. CONCLUSIONS: Radiofrequency ablation of AF concurrently with heart valve surgery is poorly effective in patients with multiple adverse risk factors. Patients with RHD and DVD had similar rates of sinus rhythm recovery. LA ≥50 mm was the single predictor of AF recurrence at three months.

Synthesis, structural elucidation, and catalytic properties in olefin epoxidation of the polymeric hybrid material [Mo3O9(2-[3(5)-pyrazolyl]pyridine)]n.

The reaction of [MoO2Cl2(pzpy)] (1) (pzpy = 2-[3(5)-pyrazolyl]pyridine) with water in an open reflux system (16 h), in a microwave synthesis system (120 °C, 2 h), or in a Teflon-lined stainless steel digestion bomb (100 °C, 19 h) gave the molybdenum oxide/pyrazolylpyridine polymeric hybrid material [Mo3O9(pzpy)]n (2) as a microcrystalline powder in yields of 72­79%. Compound 2 can also be obtained by the hydrothermal reaction of MoO3, pzpy, and H2O at 160 °C for 3 d. Secondary products isolated from the reaction solutions included the salt (pzpyH)2(MoCl4) (3) (pzpyH = 2-[3(5)-pyrazolyl]pyridinium), containing a very rare example of the tetrahedral MoCl4(2­) anion, and the tetranuclear compound [Mo4O12(pzpy)4] (4). Reaction of 2 with excess tert-butylhydroperoxide (TBHP) led to the isolation of the oxodiperoxo complex [MoO(O2)2(pzpy)] (5). Single-crystal X-ray structures of 3 and 5 are described. Fourier transform (FT)-IR and FT Raman spectra for 1, 4, and 5 were assigned based on density functional theory calculations. The structure of 2 was determined from synchrotron powder X-ray diffraction data in combination with other physicochemical information. In 2, a hybrid organic­inorganic one-dimensional (1D) polymer, ∞(1)[Mo3O9(pzpy)], is formed by the connection of two very distinct components: a double ladder-type inorganic core reminiscent of the crystal structure of MoO3 and 1D chains of corner-sharing distorted {MoO4N2} octahedra. Compound 2 exhibits moderate activity and high selectivity when used as a (pre)catalyst for the epoxidation of cis-cyclooctene with TBHP. Under the reaction conditions used, 2 is poorly soluble and is gradually converted into 5, which is at least partly responsible for the catalytic reaction.

Radiofrequency ablation of atrial fibrillation during concomitant cardiac surgery.

OBJECTIVES: We present the experience of our centre with radiofrequency ablation of atrial fibrillation concomitantly with cardiac surgery Methods: 170 patients underwent atrial fibrillation ablation with uni/bipolar-radiofrequency. They were followed for 3-months and then as appropriate for the cardiac disease. In 2013, patients still alive underwent rhythm monitoring with ECG and 24-hour tape if in sinus rhythm RESULTS: Mean age was 65 years old and 42% of the patients were male. Paroxysmal AF was rare (7%). Most patients had preserved ejection fraction and dilated left atria (diameter 53.2±7.5 mm). The most common indication for cardiac surgery was valve disease. More than 75% of the patients underwent prophylactic closure of the left atrial appendage. Pulmonary vein isolation was performed in all patients, followed by other left atrial ablation lines. Overall, surgical complications were rare, being the most frequent pacemaker implantation (15%). Median length of stay was 9 days (p25-p75:7-14). At discharge, 69% of the patients were in sinus rhythm, being 90% on anticoagulation and 69% on amiodarone. In-hospital mortality was less than 3% (5 patients), none of them related to the ablation procedure. At 3 months, 50% of the patients were in sinus rhythm, being 92% on anticoagulation and 75% on antiarrhythmic drugs. Direct current cardioversion was successful in 8 of 12 patients. In the multivariate analysis, being in sinus rhythm at discharge was the single independent predictor of maintaining sinus rhythm at 3 months. In 2013 (469 patients-year), 40% of the patients were in sinus rhythm, being 80% on anticoagulation and 45% on antiarrhythmic drugs. CONCLUSIONS: Concurrent atrial fibrillation ablation with radiofrequency achieves satisfactory and stable recovery of sinu rhythm without adding significant operative risk and post-operative complications.

Low level genome mistranslations deregulate the transcriptome and translatome and generate proteotoxic stress in yeast.

BACKGROUND: Organisms use highly accurate molecular processes to transcribe their genes and a variety of mRNA quality control and ribosome proofreading mechanisms to maintain intact the fidelity of genetic information flow. Despite this, low level gene translational errors induced by mutations and environmental factors cause neurodegeneration and premature death in mice and mitochondrial disorders in humans. Paradoxically, such errors can generate advantageous phenotypic diversity in fungi and bacteria through poorly understood molecular processes. RESULTS: In order to clarify the biological relevance of gene translational errors we have engineered codon misreading in yeast and used profiling of total and polysome-associated mRNAs, molecular and biochemical tools to characterize the recombinant cells. We demonstrate here that gene translational errors, which have negligible impact on yeast growth rate down-regulate protein synthesis, activate the unfolded protein response and environmental stress response pathways, and down-regulate chaperones linked to ribosomes. CONCLUSIONS: We provide the first global view of transcriptional and post-transcriptional responses to global gene translational errors and we postulate that they cause gradual cell degeneration through synergistic effects of overloading protein quality control systems and deregulation of protein synthesis, but generate adaptive phenotypes in unicellular organisms through activation of stress cross-protection. We conclude that these genome wide gene translational infidelities can be degenerative or adaptive depending on cellular context and physiological condition.

Tricarbonyl-Pyrazine-Molybdenum(0) Metal-Organic Frameworks for the Storage and Delivery of Biologically Active Carbon Monoxide.

Metal-organic frameworks (MOFs) have high potential as nanoplatforms for the storage and delivery of therapeutic gasotransmitters or gas-releasing molecules. The aim of the present study was to open an investigation into the viability of tricarbonyl-pyrazine-molybdenum(0) MOFs as carbon monoxide-releasing materials (CORMAs). A previous investigation found that the reaction of Mo(CO)6 with excess pyrazine (pyz) in a sealed ampoule gave a mixture comprising a major triclinic phase with pyz-occupied hexagonal channels, formulated as fac-Mo(CO)3(pyz)3/2·1/2pyz (Mo-hex), and a minor dense cubic phase, formulated as fac-Mo(CO)3(pyz)3/2 (Mo-cub). In the present work, an open reflux method in toluene has been optimized for the large-scale synthesis of the pure Mo-cub phase. The crystalline solids Mo-hex and Mo-cub were characterized by powder X-ray diffraction (PXRD), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), FT-IR and FT-Raman spectroscopies, and 13C{1H} cross-polarization (CP) magic-angle spinning (MAS) NMR spectroscopy. The release of CO from the MOFs was studied by the deoxy-myoglobin (deoxy-Mb)/carbonmonoxy-myoglobin (MbCO) UV-vis assay. Mo-hex and Mo-cub release CO upon contact with a physiological buffer in the dark, delivering 0.35 and 0.22 equiv (based on Mo), respectively, after 24 h, with half-lives of 3-4 h. Both materials display high photostability such that the CO-releasing kinetics is not affected by irradiation of the materials with UV light. These materials are attractive as potential CORMAs due to the slow release of a high CO payload. In the solid-state and under open air, Mo-cub underwent almost complete decarbonylation over a period of 4 days, corresponding to a theoretical CO release of 10 mmol per gram of material.

A Capsid Protein Fragment of a Fusagra-like Virus Found in Carica papaya Latex Interacts with the 50S Ribosomal Protein L17.

Papaya sticky disease is caused by the association of a fusagra-like and an umbra-like virus, named papaya meleira virus (PMeV) and papaya meleira virus 2 (PMeV2), respectively. Both viral genomes are encapsidated in particles formed by the PMeV ORF1 product, which has the potential to encode a protein with 1563 amino acids (aa). However, the structural components of the viral capsid are unknown. To characterize the structural proteins of PMeV and PMeV2, virions were purified from Carica papaya latex. SDS-PAGE analysis of purified virus revealed two major proteins of ~40 kDa and ~55 kDa. Amino-terminal sequencing of the ~55 kDa protein and LC-MS/MS of purified virions indicated that this protein starts at aa 263 of the deduced ORF1 product as a result of either degradation or proteolytic processing. A yeast two-hybrid assay was used to identify Arabidopsis proteins interacting with two PMeV ORF1 product fragments (aa 321-670 and 961-1200). The 50S ribosomal protein L17 (AtRPL17) was identified as potentially associated with modulated translation-related proteins. In plant cells, AtRPL17 co-localized and interacted with the PMeV ORF1 fragments. These findings support the hypothesis that the interaction between PMeV/PMeV2 structural proteins and RPL17 is important for virus-host interactions.

Synthesis, structural elucidation, and application of a pyrazolylpyridine-molybdenum oxide composite as a heterogeneous catalyst for olefin epoxidation.

The reaction of [MoO(2)Cl(2)(pypzEA)] (1) (pypzEA = ethyl[3-(pyridin-2-yl)-1H-pyrazol-1-yl]acetate) with water in a Teflon-lined stainless steel autoclave (100 °C) or in an open reflux system leads to the isolation of the molybdenum oxide/pyrazolylpyridine composite material [Mo(2)O(6)(HpypzA)] (2; HpypzA = [3-(pyridinium-2-yl)-1H-pyrazol-1-yl]acetate). The solid state structure of 2 was solved through single crystal and powder X-ray diffraction analyses in conjunction with information derived from FT-IR and (13)C CP MAS NMR spectroscopies and elemental analyses. In the asymmetric unit of 2, two crystallographically distinct Mo(6+) centers are bridged by a syn,syn-carboxylate group of HpypzA. The periodic repetition of these units along the a axis of the unit cell leads to the formation of a one-dimensional composite polymer, (∞)(1)[Mo(2)O(6)(HpypzA)]. The outstretched pyrazolylpyridine groups of adjacent polymers interdigitate to form a zipper-like motif, generating strong onset π-π contacts between adjacent rings of coordinated HpypzA molecules. The composite oxide 2 is a stable heterogeneous catalyst for liquid-phase olefin epoxidation.

A novel dinuclear MoVI complex with tris(3,5-dimethyl-1H-pyrazol-1-yl)methane.

Recrystallization of [MoO(2)Cl{HC(3,5-Me(2)pz)(3)}]Cl [where HC(3,5-Me(2)pz)(3) is tris(3,5-dimethyl-1H-pyrazol-1-yl)methane] led to the isolation of large quantities of the dinuclear complex dichlorido-2κ(2)Cl-µ-oxido-κ(2)O:O-tetraoxido-1κ(2)O,2κ(2)O-[tris(3,5-dimethyl-1H-pyrazol-1-yl-1κN(2))methane]dimolybdenum(IV) acetonitrile monosolvate, [Mo(2)Cl(2)O(4)(C(16)H(22)N(6))]·CH(3)CN or [{MoO(2)Cl(2)}(µ(2)-O){MoO(2)[HC(3,5-Me(2)pz)(3)]}]·CH(3)CN. At 150 K, this complex cocrystallizes in the orthorhombic space group Pbcm with an acetonitrile molecule. The complex has mirror symmetry: only half of the complex constitutes the asymmetric unit and all the heavy elements (namely Mo and Cl) are located on the mirror plane. The acetonitrile molecule also lies on a mirror plane. The two crystallographically independent Mo(6+) centres have drastically different coordination environments: while one Mo atom is hexacoordinated and chelated to HC(3,5-Me(2)pz)(3) (which occupies one face of the octahedron), the other Mo atom is instead pentacoordinated, having two chloride anions in the apical positions of the distorted trigonal bipyramid. This latter coordination mode of Mo(VI) was found to be unprecedented. Individual complexes and solvent molecules are close-packed in the solid state, mediated by various supramolecular contacts.