Calix[4]arene-based Supramolecular Gels for Mercury Ion Removal in Water.

A calix[4]arene-based gelator 1, with lower-rim mono triazolylpyridine group, capable of spontaneous self-assembly into microspheres in different ethanol/H2 O mixtures, is synthesized. The concentration-dependent 1 H NMR spectra and X-ray single-crystal structure of 1 provided evidence for self-assembly of gelator 1 via cooperative interactions of intermolecular noncovalent forces. Furthermore, metallogels by self-assembly of 1 was found to exhibit remarkable selectivity toward Hg2+ ions. 1 H NMR spectra support that Hg2+ ion was bound to the nitrogen atoms of two coordination sites of 1, which composed of triazole and pyridine. Moreover, the results of field emission scanning electron microscopy and rheology experiments indicated that Hg2+ ions not only enhanced the gelling ability of gelator 1 in ethanol but also led to morphological change of its self-assembly through metal-ligand interactions. Finally, the in situ gelation, triggered by mixing a gelator solution of 1 in ethanol with water samples such as deionized (DI), tap, and lake water, leads to the effective removal of Hg(II) from a water sample which reduced from 400 to 1.6 ppm.

A highly selective chromogenic and fluorogenic chemodosimeter for dual detection of Cu2+ based on a redox-active calix[4]arene with isoxazolylchloroanthracene.

Calix[4]arene 1, with two lower-rim isoxazolylchloroanthracene groups, is shown to be not only a chromogenic but also a fluorogenic chemodosimeter for the selective sensing of Cu2+. The binding properties of ligand 1 and control compounds 2 and 3 toward metal ions in CH3CN/CHCl3 (v/v, 1 : 1) were investigated by UV-vis and fluorescence spectroscopy. The results showed that only ligand 1 was highly selective for Cu2+ ions. When complexed with Cu2+, ligand 1 displayed a new absorption band around 435 nm and the color of the solution changed from colorless to yellow. Furthermore, the fluorescence of ligand 1 was severely quenched by Cu2+ and the limit of detection (LOD) was determined to be 1.674 µM. Therefore, compound 1 is not only a chromogenic but also a fluorogenic sensor for the detection of Cu2+ ions over other metal ions examined. When complexed with ligand 1, Cu2+ was reduced to Cu+ by the free phenolic-OH of ligand 1 and concurrently the phenol was oxidized by Cu2+ to quinones. The 1H NMR, EPR, and FTIR spectra provided evidence for the redox behavior of ligand 1 with Cu2+. The isolation of calix[4]diquinone 8 and Cu(CH3CN)4ClO4 from the reaction of ligand 1 with Cu(ClO4)2 confirmed their redox reaction.

Hetero-interpenetrating porous coordination polymers.

Interpenetrating porous coordination polymers (IPCPs) consist of two or more networks that are mechanically interlocked to form a coherent structure. The framework topology and the chemical composition are the two important criteria of interpenetrating networks to distinguish homo-IPCPs from hetero-IPCPs. Compared to rich homo-IPCPs, hetero-IPCPs remain rare and are formed rather unexpectedly. This Frontier article highlights hetero-IPCPs in accordance with the difference and/or identity of individual networks in terms of the framework topology and the chemical composition.

Zinc(II)-Organic Framework Films with Thermochromic and Solvatochromic Applications.

Multiple-stimuli-responsive photoluminescence films based on a ZnII -organic framework, {[Zn2 (Htpim)(3,4-pydc)2 ]⋅4 DMF⋅4 H2 O}n (1, Htpim=2,4,5-tri(4-pyridyl)imidazole, 3,4-H2 pydc=3,4-pyridinedicarboxylic acid), were fabricated. This compound consisted of a 2D corrugated layer, {Zn(3,4-pydc)}n , which was further pillared using a Y-shaped pillar N-donor ligand (Htpim) to form a 3D-pillared-layer framework with 1D open channels. The rectangular channels in the as-synthesized compound are fully occupied by guest DMF and H2 O molecules. The framework exhibits instant and reversible thermochromic properties corresponding to the removal of different H2 O and DMF guest molecules as temperature increases. The pale-yellow crystal undergoes significant redshifting to a greenish emission centered at 530 nm. Compound 1 also showed remarkable solvatochromic effects in the presence of various organic solvents without affecting its structural integrity. In addition, polycrystalline MOF films were grown on an α-Al2 O3 support for switchable and fast-response thermochromic and solvatochromic sensors.

An Unprecedented Interpenetrating Structure Built from Two Differently Bonded Frameworks: Synthesis, Characteristics, and Efficient Removal of Anionic Dyes from Aqueous Solutions.

The first example of one single crystal (NTOU-5) containing two different organic-inorganic hybrid open-framework structures was obtained using a hydro(solvo)thermal method and structurally characterized by single-crystal X-ray diffraction. Remarkably, under the same synthetic conditions, the zinc ions are respectively coordinated by oxalic acid (OX) and 1,2,4,5-tetrakis(imidazol-1-ylmethyl)benzene (TIMB) linkers to form two significantly different frameworks: anionic [Zn2 (OX)3 ]2- and cationic [Zn(TIMB)]2+ networks that interweave with each other to give an unprecedented interpenetrating structure with two differently-bonded open-frameworks. From the inorganic chemistry perspective, it is extremely difficult to control to which metal center the oxygen-donor linkers or/and nitrogen-donor ligands bind. A mixed Co/Zn analogue was also obtained by a similar method. The single-crystal XRD and EDS analyses indicate that the octahedral Zn ions of the anionic framework are replaced by cobalt cations, whereas the Zn ions in the tetrahedral positions of the cationic networks remain intact. This leads to the formation of the interpenetrating analogue with a mixed metal composition. Furthermore, NTOU-5 shows structural stability and efficiently removes organic dyes from aqueous solutions at concentrations of 10 ppm.

Rare metal-ion metathesis of a tetrahedral Zn(ii) core of a noncentrosymmetric (3,4)-connected 3D MOF.

An SHG-active noncentrosymmetric (3,4)-connected Zn(ii)-organic framework, {[Zn2(4-abpt)(3,4-pydc)2]·2DMAc·3MeOH·H2O}n (1-Zn), was synthesized using a mixed-ligand system. The 1-Zn framework undergoes metal metathesis, with the complete exchange of the tetrahedrally coordinated ZnII ions with CuII ions while retaining the integrity of the network.

Modified Separator Performing Dual Physical/Chemical Roles to Inhibit Polysulfide Shuttle Resulting in Ultrastable Li-S Batteries.

In this paper we describe a modified (AEG/CH) coated separator for Li-S batteries in which the shuttling phenomenon of the lithium polysulfides is restrained through two types of interactions: activated expanded graphite (AEG) flakes interacted physically with the lithium polysulfides, while chitosan (CH), used to bind the AEG flakes on the separator, interacted chemically through its abundance of amino and hydroxyl functional groups. Moreover, the AEG flakes facilitated ionic and electronic transfer during the redox reaction. Live H-cell discharging experiments revealed that the modified separator was effective at curbing polysulfide shuttling; moreover, X-ray photoelectron spectroscopy analysis of the cycled separator confirmed the presence of lithium polysulfides in the AEG/CH matrix. Using this dual functional interaction approach, the lifetime of the pure sulfur-based cathode was extended to 3000 cycles at 1C-rate (1C = 1670 mA/g), decreasing the decay rate to 0.021% per cycle, a value that is among the best reported to date. A flexible battery based on this modified separator exhibited stable performance and could turn on multiple light-emitting diodes. Such modified membranes with good mechanical strength, high electronic conductivity, and anti-self-discharging shield appear to be a scalable solution for future high-energy battery systems.

Expression of hepatitis B virus surface antigens induces defective gonad phenotypes in Caenorhabditis elegans.

AIM: To test whether a simple animal, Caenorhabditis elegans (C. elegans), can be used as an alternative model to study the interaction between hepatitis B virus antigens (HBsAg) and host factors. METHODS: Three plasmids that were able to express the large, middle and small forms of HBsAgs (LHBsAg, MHBsAg, and SHBsAg, respectively) driven by a ubiquitous promoter (fib-1) and three that were able to express SHBsAg driven by different tissue-specific promoters were constructed and microinjected into worms. The brood size, egg-laying rate, and gonad development of transgenic worms were analyzed using microscopy. Levels of mRNA related to endoplasmic reticulum stress, enpl-1, hsp-4, pdi-3 and xbp-1, were determined using reverse transcription polymerase reaction (RT-PCRs) in three lines of transgenic worms and dithiothreitol (DTT)-treated wild-type worms. RESULTS: Severe defects in egg-laying, decreases in brood size, and gonad retardation were observed in transgenic worms expressing SHBsAg whereas moderate defects were observed in transgenic worms expressing LHBsAg and MHBsAg. RT-PCR analysis revealed that enpl-1, hsp-4 and pdi-3 transcripts were significantly elevated in worms expressing LHBsAg and MHBsAg and in wild-type worms pretreated with DTT. By contrast, only pdi-3 was increased in worms expressing SHBsAg. To further determine which tissue expressing SHBsAg could induce gonad retardation, we substituted the fib-1 promoter with three tissue-specific promoters (myo-2 for the pharynx, est-1 for the intestines and mec-7 for the neurons) and generated corresponding transgenic animals. Moderate defective phenotypes were observed in worms expressing SHBsAg in the pharynx and intestines but not in worms expressing SHBsAg in the neurons, suggesting that the secreted SHBsAg may trigger a cross-talk signal between the digestive track and the gonad resulting in defective phenotypes. CONCLUSION: Ectopic expression of three forms of HBsAg that causes recognizable phenotypes in transgenic worms suggests that C. elegans can be used as an alternative model for studying virus-host interactions because the resulting phenotype is easily detected through microscopy.

New 3 D Tubular Porous Structure of an Organic-Zincophosphite Framework with Interesting Gas Adsorption and Luminescence Properties.

A new 3D tubular zinc phosphite, Zn2 (C22 H22 N8 )0.5 (HPO3 )2 ⋅H2 O (1), incorporating a tetradentate organic ligand was synthesized under hydro(solvo)thermal conditions and structurally characterized by single-crystal X-ray diffraction. Compound 1 is the first example of inorganic zincophosphite chains being interlinked through 1,2,4,5-tetrakis(imidazol-1-ylmethyl)benzene to form a tubular porous framework with unusual organic-inorganic hybrid channels. The thermal and chemical stabilities, high capacity for CO2 adsorption compared to that for N2 adsorption, and interesting optical properties of LED devices fabricated using this compound were also studied.

Genetic control of nucleolar size: An evolutionary perspective.

Exploiting a C. elegans mutant (ncl-1) exhibiting nucleolar abnormalities, we recently identified the let-7/ncl-1/fib-1 genetic cascade underlying proper rRNA abundance and nucleolar size. These 3 factors, let-7 (a miRNA), NCL-1 (a member of the TRIM-NHL family), and fibrillarin (a nucleolar methyltransferase), are evolutionarily conserved across metazoans. In this article, we provide several lines of bioinformatic evidence showing that human and Drosophila homologues of C. elegans NCL-1, TRIM-71 and Brat, respectively, likely act as translational suppressors of fibrillarin. Moreover, since their 3'-UTRs contain putative target sites, they may also be under the control of the let-7 miRNA. We hypothesize that let-7, TRIM and fibrillarin contribute activities in concert, and constitute a conserved network controlling nucleolar size in eukaryotes. We provide an in-depth literature review of various molecular pathways, including the let-7/ncl-1/fib-1 genetic cascade, implicated in the regulation of nucleolar size.

A Genetic Cascade of let-7-ncl-1-fib-1 Modulates Nucleolar Size and rRNA Pool in Caenorhabditis elegans.

Ribosome biogenesis takes place in the nucleolus, the size of which is often coordinated with cell growth and development. However, how metazoans control nucleolar size remains largely unknown. Caenorhabditis elegans provides a good model to address this question owing to distinct tissue distribution of nucleolar sizes and a mutant, ncl-1, which exhibits larger nucleoli than wild-type worms. Here, through a series of loss-of-function analyses, we report that the nucleolar size is regulated by a circuitry composed of microRNA let-7, translation repressor NCL-1, and a major nucleolar pre-rRNA processing protein FIB-1/fibrillarin. In cooperation with RNA binding proteins PUF and NOS, NCL-1 suppressed the translation of FIB-1/fibrillarin, while let-7 targeted the 3'UTR of ncl-1 and inhibited its expression. Consequently, the abundance of FIB-1 is tightly controlled and correlated with the nucleolar size. Together, our findings highlight a novel genetic cascade by which post-transcriptional regulators interplay in developmental control of nucleolar size and function.

The first zinc phosphite with remarkable structural and functional transformations.

A new zinc phosphite exhibited remarkable structural transformations upon heat stimulation to convert into a dehydrated form (NCU-2a) and a new structure, NCU-2b. The gas adsorption properties of the materials as well as the luminescence properties of LED devices fabricated using these materials were also investigated.

Organic-inorganic hybrid zinc phosphate with 28-ring channels.

An organic-inorganic hybrid zinc phosphate with 28-ring channels was synthesized by use of an organic ligand instead of organic amine template under a hydro(solvo)thermal condition. This crystalline zinc phosphate contains large channels constructed from 28 zinc and phosphate tetrahedral units. The walls of the channels consist of two types of zincophosphate chains, in which the Zn atoms are coordinated by 2,4,5-tri(4-pyridyl)-imidazole ligands as pendent groups. This compound exhibits yellow emission and interesting properties of removing cobalt, cadmium, and mercury cations from aqueous solution. A new two-dimensional organic-inorganic hybrid zincophosphate was also obtained by changing the solvent mixture ratios in the synthesis.

Control of light-promoted [2+2] cycloaddition reactions by a remote ancillary regulatory group that is covalently attached to rhenium rectangles.

The high-yielding self-assembly of three neutral rhenium(I) rectangles, [Re(2)(CO)(6)(L)(bpe)](2) (1 a, L=2,2'-biimidazolate (biim); 1 b, L=2,2'-bisbenzimidazolate (bbim); 1 c, L=2,2'-bis(4,5-dimethylimidazolate) (bdmim); bpe=trans-1,2-bis(4-pyridyl)ethylene), under hydrothermal conditions is described. The rectangles were structurally characterized by spectroscopic techniques and further confirmed by single-crystal X-ray diffraction. Upon irradiation with a Hg lamp at 365 nm, the bpe ligands of rectangles 1 a and 1 b underwent [2+2] photocycloaddition reactions to produce [{(Re(CO)(3))(2)L}(2)(4,4'-tpcb)(2)] (2 a, L=biim; 2 b, L=bbim; 4,4'-tpcb=1,2,3,4-tetrakis(4-pyridyl)cyclobutane) through a single-crystal-to-single-crystal (SCSC) transformation. However, rectangle 1 c, which contained methyl groups on the 2,2'-biimidazolate ligand, failed to undergo cycloaddition, even after prolonged irradiation. This result indicates that the light-induced cycloaddition reaction can be preferentially controlled by the remote regulatory substituents, which are attached onto the same backbone of the rectangle complex. This transformation is the first reported utilization of a remote ancillary regulatory ligand that is covalently attached onto a coordination compound to control the [2+2] cycloaddition reaction.

The nucleolus of Caenorhabditis elegans.

Nucleolar size and appearance correlate with ribosome biogenesis and cellular activity. The mechanisms underlying changes in nucleolar appearance and regulation of nucleolar size that occur during differentiation and cell cycle progression are not well understood. Caenorhabditis elegans provides a good model for studying these processes because of its small size and transparent body, well-characterized cell types and lineages, and because its cells display various sizes of nucleoli. This paper details the advantages of using C. elegans to investigate features of the nucleolus during the organism's development by following dynamic changes in fibrillarin (FIB-1) in the cells of early embryos and aged worms. This paper also illustrates the involvement of the ncl-1 gene and other possible candidate genes in nucleolar-size control. Lastly, we summarize the ribosomal proteins involved in life span and innate immunity, and those homologous genes that correspond to human disorders of ribosomopathy.

Hepatitis D antigens cause growth retardation and brood-size reduction in C. elegans.

Caenorhabditis elegans is a model organism that has been used to study human bacterial and viral pathogenesis. We report here the expression of human hepatitis delta viral antigens (HDAg) in C. elegans and measure the effect on the sterility, growth, and brood size in transgenic worms. Expression of HDAg under two different promoters, fib-1 (a ubiquitous promoter) and myo-2 (a pharynx-specific promoter), was achieved in C. elegans using dicistronic or tricistronic vectors derived from the operon CEOP5428. Transgenic worms expressing HDAg ubiquitously resulted in 20% to 70% sterility while those expressing HDAg in the pharynx displayed 70% sterility. Most of worms expressing HDAg in pharynx were arrested at larvae stage 2 or 3 and displayed a 70% reduction in brood size. Domain mapping experiments suggested that the nuclear localization signal of HDAg is required for the observed effect. Heat-shock induction of HDAg expression revealed that L4 larvae were the most sensitive to brood size reduction. These studies demonstrate that C. elegans can provide an additional model for studying HDAg interactions with host targets.

Highly emissive cyclometalated rhenium metallacycles: structure-luminescence relationship.

We report on a series of new self-assembled cyclometalated dirhenium(I) metallacyclic complexes via an unprecedented rhenium-mediated C-H bond activation and the relationship between their structures and luminescence properties.

Vectors for co-expression of two genes in Caenorhabditis elegans.

To meet the increasing need of simultaneously co-expressing two different genes in the same cell of transgenic Caenorhabditis elegans, here, we report the establishment of dicistronic vectors that contain an intercistronic region (ICR) of the C. elegans operon, CEOP5428. In these vectors, a green fluorescence protein (GFP) and a red FP (RFP) genes were placed in the first and second cistrons, respectively, which were separated by the ICR. Driven by the fibrillarin (fib-1) or myo-2 promoter, the GFP- and RFP-fusion proteins were consistently co-expressed in the entire worm cells or in the pharynx muscle cells of the transgenic worms, respectively. Our work demonstrates that ICR-containing dicistronic vectors could be developed into versatile co-expression systems in C. elegans for functional analysis of genes of interest.

New insights into polycistronic transcripts in eukaryotes.

In bacteria and archaea, many functionally related genes are organized into operons in order to be transcribed and translated simultaneously. Operons are rarely seen in eukaryotes except for the Trypanosome and nematode, in which they are first transcribed into polycistronic transcripts but then processed into individual mature mRNAs. Recently, several researchers described the findings of polycistronic transcripts also in insects, which revised the previous thoughts that polycistronic genes were absent or few in eukaryotes. Similar to prokaryotic operons, the encoded peptides or proteins are translated simultaneously from a single polycistronic mRNA, providing new insights into the evolution of polycistronic genes. More interestingly, one type of the newly identified polycistronic genes encodes biologically important peptides composed of as few as 11 amino acids. These new findings will spur scientists to identify more small peptides in genome-solved organisms, and change the definition of coding sequences in genomic annotation.

Psychiatric manifestations in young females with congenital adrenal hyperplasia in Taiwan.

BACKGROUND: Congenital adrenal hyperplasia (CAH) is a syndrome of prenatal and/or postnatal androgen excess secondary to genetic deficits in the cytochrome p450 enzymes of the cortisol synthesis pathway. Women with CAH may suffer from different degrees of androgenization. This study documented psychiatric manifestations in young women born with CAH in Taiwan. METHODS: From July 1, 2005 to February 31, 2006 the psychiatric morbidity, gender identity and sex-typed behavior during childhood of 11 young women with CAH were assessed either using questionnaire-based semi-structured interviews or self-reported questionnaires. RESULTS: Of the 11 young women (mean age 15.3 +/- 5.6 years), 3 (27.3%) had salt-wasting CAH and 8 (72.7%) had simple-virilizing CAH. Two patients without prior gender assignment (delayed diagnosis) were evaluated for primary amenorrhea at age 19 and 24 years, respectively. Four of the eleven participants (36.4%) had had an axis I psychiatric diagnosis within the past year. The subjects with more atypical sex-typed behavior in childhood tended to have a higher risk of minor psychiatric illness (r = -0.706, p < 0.05). CONCLUSIONS: This study examined the impact of CAH on the patients' psychological wellbeing. Psychiatric needs were found to be unmet. Earlier psychiatric evaluation and intervention for these patients is suggested.