Two novel lead-based coordination polymers for luminescence sensing of anions, cations and small organic molecules.

Two novel lead-based coordination polymers, namely [Pb(cbdcp)]·0.5H2O·0.5CH3OH (1) and [Pb(cbdcp)] (2), have been solvothermally constructed by using a zwitterionic ligand 4-carboxy-1-(3,4-dicarboxy-benzyl)-pyridinium chloride (abbreviated as H3cbdcpCl). Compound 1 has a three-dimensional framework displaying a valence-bonded SrAl2 topology with the 42·63·8 symbol, while compound 2 has a two-dimensional sheet structure that can be simplified into a three-dimensional ππ interaction-connected topology with the {44·62}2{48·615·85} symbol. Notably, compound 1 proved to be a promising potential luminescent sensor capable of selectively detecting anions, cations and small organic molecules, especially Cr2O72-, CrO42-, Fe3+ and nitrobenzene.

Extremely stable europium-organic framework for luminescent sensing of Cr2O72- and Fe3+ in aqueous systems.

Three novel 3D lanthanide-organic frameworks, namely [Ln2L(1,3-bdc)3]·5H2O (Ln: Eu, Sm and Dy), with a 412·63 topology based on a zwitterionic ligand, 4-bis(4-carboxylatopyridinium-1-methylene)benzene dichloride (H2LCl2), and 1,3-benzene dicarboxylic acid (1,3-H2bdc) have been synthesized hydrothermally. Notably, the Ln-MOFs are extremely stable in an aqueous system and are capable of resisting acids or bases over a wide pH range from 3 to 11. Meanwhile, an Eu-MOF is further proven to be a promising dual sensor in an aqueous system toward Cr2O72- and Fe3+.

Transcriptomic and metabolomic profiles of Chinese citrus fly, Bactrocera minax (Diptera: Tephritidae), along with pupal development provide insight into diapause program.

The Chinese citrus fly, Bactrocera minax (Enderlein), is a devastating citrus pest in Asia. This univoltine insect enters obligatory pupal diapause in each generation, while little is known about the course and the molecular mechanisms of diapause. In this study, the course of diapause was determined by measuring the respiratory rate throughout the pupal stage. In addition, the variation of transcriptomic and metabolomic profiles of pupae at five developmental stages (pre-, early-, middle-, late-, and post-diapause) were evaluated by next-generation sequencing technology and 1H nuclear magnetic resonance spectroscopy (NMR), respectively. A total of 4,808 genes were significantly altered in ten pairwise comparisons, representing major shifts in metabolism and signal transduction as well as endocrine system and digestive system. Gene expression profiles were validated by qRT-PCR analysis. In addition, 48 metabolites were identified and quantified by 1H NMR. Nine of which significantly contributed to the variation in the metabolomic profiles, especially proline and trehalose. Moreover, the samples collected within diapause maintenance (early-, middle-, and late-diapause) only exhibited marginal transcriptomic and metabolomic variation with each other. These findings greatly improve our understanding of B. minax diapause and lay the foundation for further pertinent studies.

RNA interference of a trehalose-6-phosphate synthase gene reveals its roles during larval-pupal metamorphosis in Bactrocera minax (Diptera: Tephritidae).

Trehalose is the major blood sugar in insects, which plays a crucial role as an instant source of energy and the starting substrate for chitin biosynthesis. In insects, trehalose is synthesized by catalysis of an important enzyme, trehalose-6-phosphate synthase (TPS). In the present study, a trehalose-6-phosphate synthase gene from Bactrocera minax (BmTPS) was cloned and characterized. BmTPS contained an open reading frame of 2445 nucleotides encoding a protein of 814 amino acids with a predicted molecular weight of 92.05kDa. BmTPS was detectable in all developmental stages of Bactrocera minax and expressed higher in the final- (third-) instar larvae. Tissue-specific expression patterns of BmTPS showed that it was mainly expressed in the fat body. The 20-hydroxyecdysone (20E) induced the expression of BmTPS and three genes in the chitin biosynthesis pathway. Moreover, injection of double-stranded RNA into third-instar larvae successfully silenced the transcription of BmTPS in B. minax, and thereby decreased the activity of TPS and trehalose content. Additionally, silencing of BmTPS inhibited the expression of three key genes in the chitin biosynthesis pathway and exhibited 52% death and abnormal phenotypes. The findings demonstrate that BmTPS is indispensable for larval-pupal metamorphosis. Besides, the establishment of RNAi experimental system in B. minax would lay a solid foundation for further investigation of molecular biology and physiology of this pest.

De novo Transcriptome Analysis of Chinese Citrus Fly, Bactrocera minax (Diptera: Tephritidae), by High-Throughput Illumina Sequencing.

The Chinese citrus fly, Bactrocera minax (Enderlein), is one of the most devastating pests of citrus in the temperate areas of Asia. So far, studies involving molecular biology and physiology of B. minax are still scarce, partly because of the lack of genomic information and inability to rear this insect in laboratory. In this study, de novo assembly of a transcriptome was performed using Illumina sequencing technology. A total of 20,928,907 clean reads were obtained and assembled into 33,324 unigenes, with an average length of 908.44 bp. Unigenes were annotated by alignment against NCBI non-redundant protein (Nr), Swiss-Prot, Clusters of Orthologous Groups (COG), Gene Ontology (GO), and Kyoto Encyclopedia of Genes and Genomes Pathway (KEGG) database. Genes potentially involved in stress tolerance, including 20 heat shock protein (Hsps) genes, 26 glutathione S-transferases (GSTs) genes, and 2 ferritin subunit genes, were identified. These genes may play roles in stress tolerance in B. minax diapause stage. It has previously been found that 20E application on B. minax pupae could avert diapause, but the underlying mechanisms remain unknown. Thus, genes encoding enzymes in 20E biosynthesis pathway, including Neverland, Spook, Phantom, Disembodied, Shadow, Shade, and Cyp18a1, and genes encoding 20E receptor proteins, ecdysone receptor (EcR) and ultraspiracle (USP), were identified. The expression patterns of 20E-related genes among developmental stages and between 20E-treated and untreated pupae demonstrated their roles in diapause program. In addition, 1,909 simple sequence repeats (SSRs) were detected, which will contribute to molecular marker development. The findings in this study greatly improve our genetic understanding of B. minax, and lay the foundation for future studies on this species.

Visible and NIR photoluminescence properties of a series of novel lanthanide-organic coordination polymers based on hydroxyquinoline-carboxylate ligands.

A series of novel two-dimensional (2D) lanthanide coordination polymers with 4-hydroxyquinoline-2-carboxylate (H(2)hqc) ligands, [Ln(Hhqc)(3)(H(2)O)](n)·3nH(2)O (Ln = Eu (1), Tb (2), Sm (3), Nd (4), and Gd (5)) and [Ln(Hhqc)(ox)(H(2)O)(2)](n) (Ln = Eu (6), Tb (7), Sm (8), Tm (9), Dy (10), Nd (11), Yb (12), and Gd (13); H(2)ox = oxalic acid), have been synthesized under hydrothermal conditions. Complexes 1-5 are isomorphous, which can be described as a two-dimensional (2D) hxl/Shubnikov network based on Ln(2)(CO(2))(4) paddle-wheel units, and the isomorphous complexes 6-13 feature a 2D decker layer architecture constructed by Ln-ox infinite chains cross-linked alternatively by bridging Hhqc(-) ligands. The room-temperature photoluminescence spectra of complexes Eu(III) (1 and 6), Tb(III) (2 and 7), and Sm(III) (3 and 8) exhibit strong characteristic emissions in the visible region, whereas Nd(III) (4 and 11) and Yb(III) (12) complexes display NIR luminescence upon irradiation at the ligand band. Moreover, the triplet state of H(2)hqc matches well with the emission level of Eu(III), Tb(III), and Sm(III) ions, which allows the preparation of new optical materials with enhanced luminescence properties.

Chlorine-induced assembly of a cationic coordination cage with a µ5-carbonato-bridged Mn(II)24 core.

Chlorine caged in! The chlorine-induced assembly of six shuttlecock-like tetranuclear Mn(II) building blocks generated in situ based on p-tert-butylthiacalix[4]arene and facial anions gave rise to a novel truncated distorted octahedral cationic coordination cage with a µ(5)-carbonato-bridged Mn(II)(24) core.

An interwoven Fe3L3 trigonal metallamacrocycle from an in situ ligand hydrolysis reaction.

Through an in situ hydrolysis reaction of the bishydrazone ligand H4L1 [H4L1=(HOC6H4)CH=NNHCO(C5H3N)CONHN[double bond, length as m-dash]CH(C6H4OH)], in the presence of Fe(III) ions, an interwoven trigonal metallamacrocycle [Fe3L3(H2O)3].9H2O () [H3L=(HOC6H4)CH=NNHCO(C5H3N)CO2H] containing unusually double-layered capsule-like water hexamers was obtained and characterized by elemental analysis, FT-IR, TGA, ESI-MS and X-ray crystallography.