Design and construction strategies to improve covalent organic frameworks photocatalyst's performance for degradation of organic pollutants.

Covalent organic frameworks (COFs) are a class of crystalline porous organic polymers. In recent years, COFs have received extensive attention in the field of photocatalytic degradation due to their large specific surface area, good thermal and solvent stability, and diverse structures. This review studies the progress of COF in the field of photocatalytic degradation, and summarizes the strategies to improve the photocatalytic activity of covalent organic frameworks, including the designs of ligands and structures. In particular, the design and construction of the COF composites (COF/MOF, COF/g-C3N4, COF/metal semiconductor) are discussed. The photocatalytic mechanism is described in detail, and the prospect of COFs in photocatalytic degradation is prospected.

Hollow zeolitic imidazolate framework-7 coated stainless steel fiber for solid phase microextraction of volatile biomarkers in headspace gas of breast cancer cell lines.

In this work, we reported the preparation of the hollow zeolitic imidazolate framework-7 (ZIF-7) via etching ZIF-7 with tannic acid, and further fabricated the hollow ZIF-7 coated fiber for the solid phase microextraction (SPME) of the five volatile biomarkers (acetone, isopropanol, hexanal, hexanol and decanal) generated from breast cancer cell lines. The hollow structure not only endowed higher extraction performance for the SPME of analytes, but also improved the diffusion rate of the analytes inside the hollow ZIF-7. Under the optimal conditions, the hollow ZIF-7 coated fiber offered high extraction capacity (25-153 mg g-1) and enhancement factors (EFs, 2023-11250) for the five biomarkers, good linearity (R2 > 0.9918) of acetone and isopropanol (2.5-500 µg L-1) and hexanol, hexanal, and decanal (1.0-100 µg L-1), low limits of detection (S/N = 3) of 0.07-0.53 µg L-1 and the limit of quantifications (LOQs, S/N = 10) of 0.23-1.76 µg L-1. The precisions (RSDs, %) for intra-day (n = 6), inter-day (n = 5) and fiber-to-fiber (n = 6) were 2.8-7.5%, 4.3-8.5%, and 4.2-14.6%, respectively. The high EFs of the hollow ZIF-7 coated fiber for the five biomarkers resulted from the integrated effects of the large surface area, the unique porous structure, hydrophobic interaction, gate-opening effect, and enhanced properties after etching including faster mass transport, multiple active components, and more exposed active sites. The fabricated hollow ZIF-7 coated fiber lasted at least 140 cycles of extraction/desorption/aging without obvious decrease of extraction ability and no change of crystal structure. Finally, the hollow ZIF-7 coated fiber combined with GC-FID had been successfully used to detect the five biomarkers in the headspace gas of human breast cancer cell lines (MDA-MB-231) and normal mammary cell lines (CCD-1095Sk) with the recoveries of 84-105%. These results revealed the prospect of hollow MOFs as efficient adsorbents for sample pretreatment.

Simultaneous determination of five phytohormones in mungbean sprouts of China by micellar electrokinetic chromatography.

A simple and rapid micellar electrokinetic chromatography method was developed for simultaneous determination of indole-3-acetic acid, indole-3-butyric acid, gibberellic acid, abscisic acid and naphthylacetic acid in mungbean sprouts for monitoring plant growth and development. The effects of several parameters related to the separation and determination were investigated in detail. The analysis was carried out using 10 mM borax, 10 mM sodium dihydrogen phosphate, 90 mM sodium dodecyl sulfate and 5% acetonitrile as running buffer (pH 9.0). Under optimum conditions, the method demonstrated good performance concerning linearity (r, 0.9954-0.9991), precision (0.77-4.97%), the method limit of detection (LOD) and the method limit of quantitation (LOQ) (LOD, 0.011-0.177 mg/kg; LOQ, 0.035-0.590 mg/kg) and accuracy (83.62-102.56%). The results confirmed that the method is rapid, convenient and of low cost for the determination of the phytohormones.

[Characteristics and phylogenetic analysis of mitochondrial genome in the gobies].

The vast number of species, small size and high variation of morphology make the morphological identification and classification of gobies very difficult. In this study, the complete mitochondrial genome (mitogenome) of 26 species of gobies was analyzed, aiming at accumulating the molecular information on the identification, classification and molecular evolution of gobies. The results showed that the gene composition and arrangement of mitogenome of gobies are similar to most vertebrates. Due to various degrees of repetitive sequences in the control region, the mitogenome of 26 gobies exhibits a great variation in length. The A+T content of the mitogenome is greater than 50% and the lowest frequency is for G among the four bases. Thirty-seven coding gene sequences were used to calculate the average Kimura 2-parameter genetic distance of 26 species of gobies. Acanthogobius hasta and A. ommaturus, Glossogobius olivaceus and G circumspectus were synonyms, respectively. By comparing the control region sequences of 26 gobies, the terminal associated sequences, central conserved sequence block and conserved sequence block were identified, respectively. Thirty-six coding gene sequences of 26 gobies were used to construct the phylogenetic tree and the results were different from the traditional morphological classification. The five subfamilies of Gobiidae were obviously evolved: Amblyopinae, Oxudercinae and Sicydiinae were clustered into a group and then formed a sister group with Gobionellinae; the fishes of Gobiinae had distant relationship with the four subfamilies and formed a group alone. Molecular clock analysis estimated that gobies probably originated in the late Eocene to Oligocene time and further evolved into modern characteristic gobies in the Miocene.

Molecular characterization of miiuy croaker CC chemokine gene and its expression following Vibrio anguillarum injection.

A CC chemokine gene was isolated from miiuy croaker (Miichthys miiuy) by expressed sequence tag analysis. The Mimi-CC cDNA contains an open reading frame of 429 nucleotides encoding 142 amino acid residues. The deduced Mimi-CC possesses the typical arrangement of four cysteines as found in other known CC chemokines (C³¹, C³², C56, and C7°). It shares 15.3%-37.4% identity to CC chemokines of mammal and teleost. Phylogenetic analysis showed that miiuy croaker was most closely related to Atlantic cod. Genomic analysis revealed that Mimi-CC gene consists of four exons and three introns, which is not typical of CC chemokines but resembles that of CXC chemokines. Real-time quantitative RT-PCR demonstrated that Mimi-CC is constitutively expressed in most tissues including lymphoid organs, and the highest expression of Mimi-CC transcripts in normal tissues was observed in muscle. Challenge of miiuy croaker with Vibrio anguillarum resulted in significant changes in the expression of CC chemokine transcripts in four tissues, especially in kidney and spleen.

Sequence and expression analysis of cathepsin S gene in the miiuy croaker Miichthys miiuy.

Cathepsin S (CTSS) is a lysosomal cysteine endopeptides of the papain family. In the present study, CTSS gene was isolated from miiuy croaker (Miichthys miiuy) by expressed sequence tag analysis. The complete miiuy croaker CTSS cDNA comprised 1,454 nucleotides, including 56 bp at the 5'-UTR and 394 bp at the 3'-UTR. The open reading frame is 1,017 bp, and it encodes 338 amino acid residues with a calculated molecular weight of 37.1 kDa. BLAST analysis revealed that miiuy croaker cathepsin S shared high similarity with other known cathepsin S, and it showed significant homology with that of Japanese flounder, the degree of conservation of the miiuy croaker CTSS nucleotide sequence in comparison with other teleost species ranged from 63.0 to 81.7%. The N-linked glycosylation sites and catalytic sites are conserved in miiuy croaker CTSS. The CTSS transcript was expressed in all tissues examined; high levels of transcripts of CTSS were detected liver, muscle, and fin. These results provide important information for further exploring the roles of cathepsin S in antigen processing.

Genomic sequences comparison and differential expression of miiuy croaker MHC class I gene, after infection by Vibrio anguillarum.

Major histocompatibility complex (MHC) has a central role in the adaptive immune system by presenting foreign peptide to the T-cell receptor. MHC gene family contains two main subgroups of immunologically active molecules. In order to study the molecular function and genomic characteristic of class I gene in teleost, the full lengths of MHC class Iα cDNA and genomic sequence were cloned from miiuy croaker (Miichthys miiuy). Seven exons and six introns were identified in miiuy croaker class Iα gene. This genomic structural feature of miiuy croaker is similar to that present in some fishes such as Japanese flounder and Atlantic salmon, but different from that present in some other fishes such as half-smooth tongue sole and channel catfish. The deduced amino acid sequence of class Iα gene had 25.9-54.1% identity with those of mammal and teleost. Real-time quantitative RT-PCR demonstrated that the MHC class Iα gene was ubiquitously expressed in 10 normal tissues; expression levels of MHC Iα gene were found first upregulated and then downregulated throughout the pathogenic bacteria infection process in spleen and kidney.

The complete mitochondrial genome of bighead croaker, Collichthys niveatus (Perciformes, Sciaenidae): structure of control region and phylogenetic considerations.

Sciaenidae is a diverse, commercially important family. To understand the phylogenetic position of Collichthys niveatus in this family, we present its complete mitochondrial genome sequence. The genome is 16469 bp in length and contains 37 mitochondrial genes (13 protein-coding genes, 2 ribosomal RNA genes and 22 transfer RNA genes) and a control region (CR) as in other bony fishes. Further sequencing for the complete control region was performed on Collichthys lucida. Although the conserved sequence domains such as extend termination associated sequence (ETAS) and conserved sequence block domains (CSB-1, CSB-2 and CSB-3) are recognized in the control region of the two congeneric species, the typical central conserved blocks (CSB-F, CSB-E and CSB-D) could not be detected, while they are found in Miichthys miiuy and Cynoscion acoupa of Sciaenidae and other Percoidei fishes. Phylogenetic analyses do not support the monophyly of Pseudosciaeniae, which is against with the morphological results. C. niveatus is most closely related to Larimichthys polyactis, and Collichthys and Larimichthys may be merged into one genus, based on the current datasets.

Allelic variation, balancing selection and positive selected sites detected from MHC class Iα gene of olive flounder.

Major histocompatibility complex (MHC) genes play an important role in the immune response of vertebrates. Allelic polymorphism and pattern of evolution in MHC genes has been investigated in many mammals, however, much less is known in teleost. In the present study, we have investigated complete MHC Iα gene consists of 7 exons and 6 introns in Olive flounder (Paralichthys olivaceus). Genetic variation in the MHC class Iα gene was also tested in flounder. In 32 individuals, a total of 62 alleles were detected from exon 2 of MHC class Iα gene. The rate of non-synonymous substitutions (d ( N )) occurred at a significantly higher frequency than that of synonymous substitutions (d ( S )) in PBR and non-PBR, suggesting that balancing selection for maintaining polymorphisms at the MHC Iα locus. Many positive selection sites were found to act very intensively on antigen binding sites. Our founding suggests a snapshot in an evolutionary process of MHC Iα gene evolution of the P. olivaceus.

Identification of immune genes of the miiuy croaker (Miichthys miiuy) by sequencing and bioinformatic analysis of ESTs.

Miiuy croaker (Miichthys miiuy) is an economically important fish in China. However, genomic research on this species is still in its infancy, and genomic resources are largely unavailable. In order to isolate functional genes involved in immunity, a normalized cDNA library was constructed from the spleen of the miiuy croaker. A total of 5053 ESTs from the library were sequenced and compared with sequences in the GenBank database. The 4609 high-quality ESTs were assembled into 3221 unigenes. Based on sequence similarities, 193 immune genes were identified such as major histocompatibility complex, cytokines and cytokine receptors, adhesive proteins, stress proteins, transcription factors for immune response, immunoglobulin and coagulation factors. Our study thus provides both a detailed annotation of immune genes in miiuy croaker and a collection of novel transcripts of Fc receptor-like 5 in teleost for the first time.

Gene duplication and evidence for balancing selection acting on MHC class II DAA gene of the half-smooth tongue sole (Cynoglossus semilaevis).

Allelic polymorphism and evolution mechanism of major histocompatibility complex (MHC) genes has been investigated in many mammals, however, much less is known in teleost. In order to investigate the mechanisms creating and maintaining variability at the MHC class II DAA locus, we examined the polymorphism, gene duplication and balancing selection of MHC class II DAA gene of the half-smooth tongue sole (Cynoglossus semilaevis). We described 33 alleles in the C. semilaevis, recombination and gene duplication seems to play more important roles in the origin of new alleles. The rate of non-synonymous substitutions (d(N)) occurred at a significantly higher frequency than that of synonymous substitutions (d(S)) in peptide-binding region (PBR) and non-PBR, suggesting balancing selection for maintaining polymorphisms at the MHC II DAA locus. Many positive selection sites were found to act very intensively on antigen-binding sites. Our founding suggests a snapshot in an evolutionary process of MHC-DAA gene evolution of the C. semilaevis.