Eu3+ doped ethylenediamine functionalized UiO-66 probe for fluorescence sensing of formaldehyde.

The development of probes with selectivity and prompt detection of aldehydes molecules is of great importance for protecting human health and public security. Herein, a system based on ethylenediamine (EDA) functionalized and Eu3+-doped UiO-66, namely EDA-Eu3+@UiO-66, was designed to detect formaldehyde molecules. Based on the "antenna effect" of lanthanide elements, UiO-66 transfers the absorbed energy to Eu3+ ions and emits characteristic fluorescence belonging to Eu3+. By using the fluorescence peaks of UiO-66 and Eu3+ respectively, a ratiometric fluorescence sensing probe can be constructed. Formaldehyde molecules react with the -NH2 on the surface of EDA-Eu3+@UiO-66 through an aldehyde-amine condensation reaction and connect to the functionalized surface of UiO-66. Due to the absorption of excitation light energy by formaldehyde molecules, the energy transfer efficiency from UiO-66 to Eu3+ ions is reduced, resulting in the fluorescence quenching of EDA-Eu3+@UiO-66, thus achieving selective detection of formaldehyde. The fabricated sensing platform successfully detected residual formaldehyde in frozen shrimp tail samples. The system was also used to respond to formaldehyde vapor, and a significant fluorescence quenching effect was observed. This strategy provides a sensitive, selective, and reliable method for the visual sensing of formaldehyde.

Enhancing Mental Health and Medication Adherence Among Men Who Have Sex With Men Recently Diagnosed With HIV With a Dialectical Behavior Therapy-Informed Intervention Incorporating mHealth, Online Skills Training, and Phone Coaching: Development Study Using Human-Centered Design Approach.

BACKGROUND: Mental health problems are common among men who have sex with men (MSM) living with HIV and may negatively affect medication adherence. Psychosocial interventions designed to address these urgent needs are scarce in China. Incorporating behavioral health theories into intervention development strengthens the effectiveness of these interventions. The absence of a robust theoretical basis for interventions may also present challenges to identify active intervention ingredients. OBJECTIVE: This study aims to systematically describe the development of a mobile health-based intervention for MSM recently diagnosed with HIV in China, including the theoretical basis for the content and the considerations for its technological delivery. METHODS: We used intervention mapping (IM) to guide overall intervention development, a behavioral intervention technology model for technological delivery design, and a human-centered design and cultural adaptation model for intervention tailoring throughout all steps of IM. RESULTS: The dialectical behavior therapy (DBT)-informed intervention, Turning to Sunshine, comprised 3 components: app-based individual skills learning, group-based skills training, and on-demand phone coaching. The theoretical basis for the intervention content is based on the DBT model of emotions, which fits our conceptualization of the intervention user's mental health needs. The intervention aims to help MSM recently diagnosed with HIV (1) survive moments of high emotional intensity and strong action urges, (2) change emotional expression to regulate emotions, and (3) reduce emotional vulnerability, as well as (4) augment community resources for mental health services. Technological delivery considerations included rationale of the medium, complexity, and esthetics of information delivery; data logs; data visualization; notifications; and passive data collection. CONCLUSIONS: This study laid out the steps for the development of a DBT-informed mobile health intervention that integrated app-based individual learning, group-based skills training, and phone coaching. This intervention, Turning to Sunshine, aims to improve mental health outcomes for MSM newly diagnosed with HIV in China. The IM framework informed by human-centered design principles and cultural adaptation considerations offered a systematic approach to develop the current intervention and tailor it to the target intervention users. The behavioral intervention technology model facilitated the translation of behavioral intervention strategies into technological delivery components. The systematic development and reporting of the current intervention can serve as a guide for similar intervention studies. The content of the current intervention could be adapted for a broader population with similar emotional struggles to improve their mental health outcomes.

The combined use of arbuscular mycorrhizal fungi, biochar and nitrogen fertilizer is most beneficial to cultivate Cichorium intybus L. in Cd-contaminated soil.

We assessed Cichorium intybus L. (chicory) growth, nutrients and Cd uptake in the presence of arbuscular mycorrhizal fungi (AMF), biochar (BC) and nitrogen (N) fertilizer applications in experimental pot studies. Mycorrhizal colonization was improved by BC addition but not N addition. However, in the presence of AMF, BC and N had positive effects on shoot biomass and plants grown in the presence of all 3 components yielded the highest levels of shoot biomass compared to pair-wise combinations or individual components singly added. AMF inoculation also increased root biomass and this effect was apparent in the combinations that included AMF without BC. Fungal inoculation also led to increased contents of phosphorus (P), magnesium (Mg) and copper (Cu) in both chicory shoots and roots and potassium (K) and manganese (Mn) in roots. Moreover, in the presence of BC, AMF inoculation evidently enhanced the shoot Ca content. In contrast, the presence of AMF inhibited plant Cd absorption and BC addition further inhibited root Cd concentration following the AMF inoculation. Applying N fertilizer alone increased Cd transfering from soil to plants. However, when combined with use of AMF and BC, Cd toxicity to plants was reduced. This study demonstrated that AMF inoculation combined with BC and N fertilizer could improve chicory growth, nutrient absorption and reduction of Cd uptake in Cd-contaminated soil.

Influences of rice straw biochar and organic manure on forage soybean nutrient and Cd uptake.

This pot experiment aimed to investigate the influence of rice straw biochar (BC 0, 1, and 3%, w/w) and organic manure (OM 0, 1, and 2%, w/w) addition on the growth, nutrient and cadmium (Cd) uptake of forage soybean in 10 mg Cd kg-1 contaminated soils. Compared with non-biochar treatments, biochar decreased shoot biomass, height and nitrogen (N) contents. Organic manure markedly increased the shoot biomass, shoot phosphorus (P), potassium (K), calcium (Ca) and magnesium (Mg) concentration, and root N, P, Ca contents without biochar addition treatments, while in the case of 3% biochar, there were no significant effects on N, K, Ca, and Mg contents of shoot and root among organic manure treatments. In comparison with other treatments, the minimum Cd content of shoots and roots both occurred in the treatment of BC3%+OM2%, while shoot Cd content reached the maximum value in OM2% treatment. Thus, these results suggested that organic manure addition can elevate forage soybean yield and nutrient content, while biochar had no positive effects. High biochar (3%) addition in combination with highest dose of organic manure (2%) can decline the Cd content of soybean and contribute to the agricultural product safety.

Influences of arbuscular mycorrhizae, phosphorus fertiliser and biochar on alfalfa growth, nutrient status and cadmium uptake.

The objective of the study was to explore the influences of arbuscular mycorrhizae (AM), phosphorus (P) fertiliser, biochar application (BC) and their interactions on Medicago sativa growth, nutrient, Cd content and AM fungi-plant symbioses. Applications of both P fertiliser and BC significantly increased total biomass and P and potassium (K) uptake, regardless of AM. When no P fertiliser or BC was used, the shoot biomass and nitrogen (N), P, and K contents in the +AM treatments were 1.39, 1.54, 4.53 and 2.06 times higher than those in the -AM treatments, respectively. AM fungi only elevated the total P uptake by 44.03% when P fertiliser was applied at a rate of 30 mg P kg-1 in the absence of BC addition. With BC application or high-P fertiliser input (100 mg P kg-1), the soil available P was significantly higher than that in the other treatments, and AM fungi significantly reduced the shoot biomass. The minimum Cd concentration occurred in the shoots of alfalfas treated with BC and high-P fertiliser inputs; this concentration was lower than the maximum permitted concentration in China. Although the BC and high-P inputs could eliminate the positive mycorrhizal response, the results suggested that BC application in combination with high-P fertiliser input could not only increase forage yields but also lower Cd concentrations to meet the forage safety standards by the dilution effect.

Growth and elemental uptake of Trifolium repens in response to biochar addition, arbuscular mycorrhizal fungi and phosphorus fertilizer applications in low-Cd-polluted soils.

The aim of this study was to examine the effects of arbuscular mycorrhizal (AM) fungi, biochar (BC) addition and phosphorus (P) fertilizer applications on the mycorrhizal response, biomass and elemental uptake of Trifolium repens in cadmium (Cd)-polluted soils. The results showed that mycorrhizal colonization were significantly decreased by 100 mg P kg-1 fertilizer input. Moreover, AM fungi, BC addition and P fertilizer significantly increased shoot biomass accumulation at all treatments. In the absence of BC, the nitrogen (N), potassium (K), calcium (Ca) and magnesium (Mg) contents in the shoots were not affected by AM fungi after P fertilizer application, but the P content in the shoots significantly increased in response to AM fungi. In the absence of BC, both AM fungi and P fertilizer significantly reduced the Cd concentrations in the plant tissues as well as the soil diethylenetriaminepentaacetic acid (DTPA)-Cd concentration. These results indicated that the translocation factors (TFs) were influenced only by BC addition and that the roots could accumulate greater amounts of Cd than the shoots. On the basis of the hygienic standard for feed in China, the shoot Cd concentration in white clover was below the maximum permitted Cd concentration (1 µg g-1) across all treatments. Therefore, it is suggested that no negative mycorrhizal-white clover symbiotic relationships were observed and T. repens could be a suitable forage species for planting in soils with low concentrations of Cd contamination when BC and P fertilizer are applied.

Biochar shifts biomass and element allocation of legume-grass mixtures in Cd-contaminated soils.

Biochar amendments have been considered to increase the competitive abilities of legumes in mixed cultures. However, little is known about how biochar affects the nutrient and Cd allocation within legume-grass mixtures. Therefore, we conducted a pot experiment to explore the effects of biochar addition rate (0, 1, 2.5, and 5%) on four monocultures, the legume Trifolium repens (Tr), Lolium perenne (Lp), Dactylis glomerata (Dg) and Festuca arundinacea (Fa), and three mixed cultures, i.e., Tr + Lp, Tr + Lp + Dg, and Tr + Lp + Dg + Fa. Regardless of biochar addition, Tr plants showed the lowest aboveground Cd concentration among the monoculture treatments. Compared with non-biochar addition treatment, the 1% biochar addition significantly promoted aboveground biomass accumulation and P, K, Ca, and Mg uptake in the aboveground parts of the Tr monoculture treatments by 39.32, 39.88, 88.27, 69.68, and 51.96%, respectively. Nevertheless, the aboveground biomass and P, K, Ca, and Mg uptake as well as the proportion of these parameters in Tr plants in all plant species mixture treatments decreased after biochar application. Maximum aboveground P and Mg uptake occurred in the four-species mixture treatments without biochar addition, whereas maximum values of these parameters occurred in the three-species mixture treatments with 5% biochar addition. Shoot Cd uptake was not decreased by biochar addition at all plant species treatments. Based on the results, it was suggested that biochar could not reduce Cd uptake by increasing the proportion of legumes in the legume-grass mixtures. The complementarity effects on nutrient uptake in the plant species mixtures depended on the amount of biochar added.

Rice straw biochar and phosphorus inputs have more positive effects on the yield and nutrient uptake of Lolium multiflorum than arbuscular mycorrhizal fungi in acidic Cd-contaminated soils.

The purpose of the study was to examine biochar amendment, phosphorus (P) fertilizer and arbuscular mycorrhizal fungi (AMF) on the yield, nutrient and cadmium (Cd) absorption of Lolium multiflorum in acidic soil. It was shown that mycorrhizal inoculation had no positive influence on the plant shoot biomass and the contents of nitrogen (N), P, potassium (K), calcium (Ca) and magnesium (Mg) in plants at all biochar and P level treatments. Irrespective of mycorrhizal inoculation and P level, biochar amendments markedly elevated the soil available P and K uptake in plant tissues. In contrast, biochar significantly decreased the translocation factor of plants, soil exchangeable Cd, and acid and neutral phosphatase activities, regardless of the mycorrhizal inoculation and P fertilizer. Without P fertilization, biochar amendments significantly promoted shoot P content, while biochar amendments significantly reduced shoot P content when P fertilizer was applied. Without biochar application, P fertilizer application significantly promoted the biomass and N uptake of shoots in both AMF inoculation treatments, while P fertilizer increased these only in the presence of biochar and mycorrhizal inoculation. The increased N content induced by the biochar amendment elevated the shoot N:P ratio and alleviated the N deficiency with P fertilizer input. Thus, we concluded that the addition of biochar and P fertilizer showed more positive effects on the promotion of growth and nutrient uptake of L. multiflorum than AMF grown in acidic Cd-contaminated soils.

In vitro Approaches to Support Bioequivalence and Substitutability of Generic Proton Pump Inhibitors via Nasogastric Tube Administration.

Administration of proton pump inhibitors (PPIs) through nasogastric tubes may present risks. If the PPI drug products are not prepared properly, clogging or obstruction of nasogastric tubes can pose a safety concern. In addition, the integrity of the enteric coating of the drug product may be damaged resulting in reduced bioavailability of the active moiety. From the perspective of administration of generic PPIs when compared to the reference drug product, differences in formulation can potentially result in a greater relative risk for the generic drug product. As part of the assessment of bioequivalence, the Office of Generic Drugs (OGD) has developed a suite of in vitro testing to compare the delivery of the generic and reference products via nasogastric tubes. These in vitro tests assess essential attributes associated with the likelihood of clogging and maintenance of the enteric coating. These in vitro tests include studies evaluating sedimentation, granule size distribution, drug recovery, and acid resistance. One of the challenges is that while the administration of PPIs through nasogastric tubes is common in clinical practice, this issue is not uniformly addressed in the FDA approved label of the reference drug products. This paper discusses the design and rationale for in vitro testing of PPI formulations with respect to bioequivalence via nasogastric tube administration and in addition, it summarizes commonly occurring deficiencies in the in vitro nasogastric tube testing of 14 recent Abbreviated New Drug Applications (ANDA) submitted for five generic PPI drug products.

An allosteric mechanism for inhibiting HIV-1 integrase with a small molecule.

HIV-1 integrase (IN) is a validated target for developing antiretroviral inhibitors. Using affinity acetylation and mass spectrometric (MS) analysis, we previously identified a tetra-acetylated inhibitor (2E)-3-[3,4-bis(acetoxy)phenyl]-2-propenoate-N-[(2E)-3-[3,4-bis(acetyloxy)phenyl]-1-oxo-2-propenyl]-L-serine methyl ester; compound 1] that selectively modified Lys173 at the IN dimer interface. Here we extend our efforts to dissect the mechanism of inhibition and structural features that are important for the selective binding of compound 1. Using a subunit exchange assay, we found that the inhibitor strongly modulates dynamic interactions between IN subunits. Restricting such interactions does not directly interfere with IN binding to DNA substrates or cellular cofactor lens epithelium-derived growth factor, but it compromises the formation of the fully functional nucleoprotein complex. Studies comparing compound 1 with a structurally related IN inhibitor, the tetra-acetylated-chicoric acid derivative (2R,3R)-2,3-bis[[(2E)-3-[3,4-bis(acetyloxy)phenyl]-1-oxo-2-propen-1-yl]oxy]-butanedioic acid (compound 2), indicated striking mechanistic differences between these agents. The structures of the two inhibitors differ only in their central linker regions, with compounds 1 and 2 containing a single methyl ester group and two carboxylic acids, respectively. MS experiments highlighted the importance of these structural differences for selective binding of compound 1 to the IN dimer interface. Moreover, molecular modeling of compound 1 complexed to IN identified a potential inhibitor binding cavity and provided structural clues regarding a possible role of the central methyl ester group in establishing an extensive hydrogen bonding network with both interacting subunits. The proposed mechanism of action and binding site for the small-molecule inhibitor identified in the present study provide an attractive venue for developing allosteric inhibitors of HIV-1 IN.

Subunit-specific protein footprinting reveals significant structural rearrangements and a role for N-terminal Lys-14 of HIV-1 Integrase during viral DNA binding.

To identify functional contacts between HIV-1 integrase (IN) and its viral DNA substrate, we devised a new experimental strategy combining the following two methodologies. First, disulfide-mediated cross-linking was used to site-specifically link select core and C-terminal domain amino acids to respective positions in viral DNA. Next, surface topologies of free IN and IN-DNA complexes were compared using Lys- and Arg-selective small chemical modifiers and mass spectrometric analysis. This approach enabled us to dissect specific contacts made by different monomers within the multimeric complex. The foot-printing studies for the first time revealed the importance of a specific N-terminal domain residue, Lys-14, in viral DNA binding. In addition, a DNA-induced conformational change involving the connection between the core and C-terminal domains was observed. Site-directed mutagenesis experiments confirmed the importance of the identified contacts for recombinant IN activities and virus infection. These new findings provided major constraints, enabling us to identify the viral DNA binding channel in the active full-length IN multimer. The experimental approach described here has general application to mapping interactions within functional nucleoprotein complexes.

High resolution footprinting of the hepatitis C virus polymerase NS5B in complex with RNA.

The nucleic acid binding channel of the hepatitis C virus RNA polymerase remains to be defined. Here we employed complementary footprinting techniques and show that the enzyme binds to a newly synthesized duplex of approximately seven to eight base pairs. Comparative analysis of surface topologies of free enzyme versus the nucleoprotein complex revealed certain lysines and arginines that are protected from chemical modification upon RNA binding. The protection pattern helps to define the trajectory of the nucleic acid substrate. Lys(81), Lys(98), Lys(100), Lys(106), Arg(158), Arg(386), and Arg(394) probably interact with the bound RNA. The selective protection of amino acids of the arginine-rich region in helix T points to RNA-induced conformational rearrangements. Together, these findings suggest that RNA-protein interaction through the entire substrate binding channel can modulate intradomain contacts at the C terminus.

Interactions between HIV-1 Gag molecules in solution: an inositol phosphate-mediated switch.

Retrovirus particle assembly is mediated by the Gag protein. Gag is a multi-domain protein containing discrete domains connected by flexible linkers. When recombinant HIV-1 Gag protein (lacking myristate at its N terminus and the p6 domain at its C terminus) is mixed with nucleic acid, it assembles into virus-like particles (VLPs) in a fully defined system in vitro. However, this assembly is defective in that the radius of curvature of the VLPs is far smaller than that of authentic immature virions. This defect can be corrected to varying degrees by addition of inositol phosphates to the assembly reaction. We have now explored the binding of inositol hexakisphosphate (IP6) to Gag and its effects upon the interactions between Gag protein molecules in solution. Our data indicate that basic regions at both ends of the protein contribute to IP6 binding. Gag is in monomer-dimer equilibrium in solution, and mutation of the previously described dimer interface within its capsid domain drastically reduces Gag dimerization. In contrast, when IP6 is added, Gag is in monomer-trimer rather than monomer-dimer equilibrium. The Gag protein with a mutation at the dimer interface also remains almost exclusively monomeric in IP6; thus the "dimer interface" is essential for the trimeric interaction in IP6. We discuss possible explanations for these results, including a change in conformation within the capsid domain induced by the binding of IP6 to other domains within the protein. The participation of both ends of Gag in IP6 interaction suggests that Gag is folded over in solution, with its ends near each other in three-dimensional space; direct support for this conclusion is provided in a companion manuscript. As Gag is an extended rod in immature virions, this apparent proximity of the ends in solution implies that it undergoes a major conformational change during particle assembly.

Interactions of HIV-1 Gag with assembly cofactors.

HIV-1 Gag is the only protein required for retroviral particle assembly. There is evidence suggesting that phosphatidylinositol phosphate and nucleic acid are essential for viruslike particle assembly. To elucidate structural foundations of interactions of HIV-1 Gag with the assembly cofactors PI(4,5)P2 and RNA, we employed mass spectrometric protein footprinting. In particular, the NHS-biotin modification approach was used to identify the lysine residues that are exposed to the solvent in free Gag and are protected from biotinylation by direct protein-ligand or protein-protein contacts in Gag complexes with PI(4,5)P2 and/or RNA. Of 21 surface lysines readily modified in free Gag, only K30 and K32, located in the matrix domain, were strongly protected in the Gag-PI(4,5)P2 complex. Nucleic acid also protected these lysines, but only at significantly higher concentrations. In contrast, nucleic acids and not PI(4,5)P2 exhibited strong protection of two nucleocapsid domain residues: K391 and K424. In addition, K314, located in the capsid domain, was specifically protected only in the presence of both PI(4,5)P2 and nucleic acid. We suggest that concerted binding of PI(4,5)P2 and nucleic acid to the matrix and nucleocapsid domains, respectively, promotes protein-protein interactions involving capsid domains. These protein-protein interactions must be involved in virus particle assembly.