Molecular characterization of a teleost-specific toll-like receptor 22 (tlr22) gene from yellow catfish (Pelteobagrus fulvidraco) and its transcriptional change in response to poly I:C and Aeromonas hydrophila stimuli.

Toll-like receptors (TLRs) are a class of pattern recognition receptors (PRRs) that can recognize pathogen-associated molecular patterns (PMPs) and play important roles in the innate immune system in vertebrates. In this study, we identified a teleost-specific tlr22 gene from yellow catfish (Pelteobagrus fulvidraco) and its immune roles in response to different pathogens were also determined. The open reading frame (ORF) of the tlr22 was 2892 bp in length, encoding a protein of 963 amino acids. Multiple protein sequences alignment, secondary and three-dimensional structure analyses revealed that TLR22 is highly conserved among different fish species. Phylogenetic analysis showed that the phylogenetic topology was divided into six families of TLR1, TLR3, TLR4, TLR5, TLR7 and TLR11, and TLR22 subfamily was clustered into TLR11 family. Meanwhile, synteny and gene structure comparisons revealed functional and evolutionary conservation of the tlr22 gene in teleosts. Furthermore, tlr22 gene was shown to be widely expressed in detected tissues except barbel and eye, with highest expression level in liver. The transcription of tlr22 was significantly increased in spleen, kidney, liver and gill tissues at different timepoints after Poly I:C infection, suggesting TLR22 plays critical roles in defensing virus invasion. Similarly, the transcription of tlr22 was also dramatically up-regulated in spleen, kidney and gill tissues with different patterns after Aeromonas hydrophila infection, indicating that TLR22 is also involved in resisting bacteria invasion. Our findings will provide a solid basis for the investigation the immune functions of tlr22 gene in teleosts, as well as provide useful information for disease control and treatment for yellow catfish.

Untargeted and targeted gingival metabolome in rodents reveal metabolic links between high-fat diet-induced obesity and periodontitis.

AIM: To characterize gingival metabolome in high-fat diet (HFD)-induced obesity in mice with/without periodontitis. METHODS: HFD-induced obesity mouse model was established by 16-week feeding, and a lean control group was fed with low-fat diet (n = 21/group). Both models were induced for periodontitis on the left sides by molar ligation for 10 days, whereas the right sides were used as controls. Gingival metabolome and arginine metabolism were analysed by non-targeted/targeted liquid chromatography-mass spectrometry. RESULTS: Of 2247 reference features, presence of periodontitis altered 165 in lean versus 885 in HFD mice; and HFD altered 525 in absence versus 1435 in presence of periodontitis. Compared with healthy condition, periodontitis and HFD had distinct effects on gingival metabolome. Metabolomic impacts of periodontitis were generally greater in HFD mice versus lean controls. K-medoids clustering showed that HFD amplified the impacts of periodontitis on gingival metabolome in both intensity and extensity. Ten metabolic pathways were enriched, including 2 specific to periodontitis, 5 specific to HFD and 3 shared ones. Targeted validation on arginine metabolism confirmed the additive effects between HFD and periodontitis. CONCLUSION: The obese population consuming excessive HFD display amplified metabolic response to periodontitis, presenting a metabolic susceptibility to exacerbated periodontal destruction.

Genetic variants in DNA repair pathway genes and risk of esophageal squamous cell carcinoma and gastric adenocarcinoma in a Chinese population.

The DNA repair pathways help to maintain genomic integrity and therefore genetic variation in the pathways could affect the propensity to develop cancer. Selected germline single nucleotide polymorphisms (SNPs) in the pathways have been associated with esophageal cancer and gastric cancer (GC) but few studies have comprehensively examined the pathway genes. We aimed to investigate associations between DNA repair pathway genes and risk of esophageal squamous cell carcinoma (ESCC) and GC, using data from a genome-wide association study in a Han Chinese population where ESCC and GC are the predominant cancers. In sum, 1942 ESCC cases, 1758 GC cases and 2111 controls from the Shanxi Upper Gastrointestinal Cancer Genetics Project (discovery set) and the Linxian Nutrition Intervention Trials (replication set) were genotyped for 1675 SNPs in 170 DNA repair-related genes. Logistic regression models were applied to evaluate SNP-level associations. Gene- and pathway-level associations were determined using the resampling-based adaptive rank-truncated product approach. The DNA repair pathways overall were significantly associated with risk of ESCC (P = 6.37 × 10(-4)), but not with GC (P = 0.20). The most significant gene in ESCC was CHEK2 (P = 2.00 × 10(-6)) and in GC was CLK2 (P = 3.02 × 10(-4)). We observed several other genes significantly associated with either ESCC (SMUG1, TDG, TP53, GTF2H3, FEN1, POLQ, HEL308, RAD54B, MPG, FANCE and BRCA1) or GC risk (MRE11A, RAD54L and POLE) (P < 0.05). We provide evidence for an association between specific genes in the DNA repair pathways and the risk of ESCC and GC. Further studies are warranted to validate these associations and to investigate underlying mechanisms.

The complete mitochondrial genome of Percocypris retrodorsalis (Teleostei, Cypriniformes) in Nujiang River: characterization and phylogenetic position.

Percocypris retrodorsalis is an endemic species found in Nujiang River and Lantsang. In this study, the complete mitochondrial genome of P. retrodorsalis was determined. The circular mitochondrial genome was 16,576 bp long, containing 13 protein-coding genes, two ribosomal RNA genes (rRNA), 22 transfer RNA (tRNA) genes, an origin of light-strand replication (OL), and one displacement loop locus (D-loop). Most genes were encoded on the heavy strand except for ND6 and eight tRNA genes. There were 11 regions of gene overlaps totaling 29 bp and seven intergenic spacer regions totaling 37 bp. The phylogenetic analyses were performed on the concatenated dataset of 28 protein-coding genes (PCGs), and the fishes of genus Percocypris may have a close relationship with Schizothoracins (Schizothoracinae) compared to other Cyprinidae fishes.

Biodistribution and Toxicity Assessment of Superparamagnetic Iron Oxide Nanoparticles In Vitro and In Vivo.

Biodistribution and toxicity assessment are critical for safe clinical use of newly developed medicines. Superparamagnetic iron oxide nanoparticles (SPION) are effective carriers for targeted drug delivery. This study aimed to examine the toxicity and biodistribution of SPION coated with polyethylenimine (PEI) (SPION-PEI) designed for small interfering RNA (siRNA) delivery both in vitro and in vivo. SPION-PEI/siRNA complexes were prepared at different weight ratios. Cytotoxic effects of SPION-PEI/siRNA on HSC-T6 cell viability were determined by using 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT). Rats were divided into three groups: a control group, a normal-saline group and a SPION-PEI/siRNA group. After a single intravenous injection, in vivo nanoparticle biodistribution and accumulation were evaluated by Prussian blue staining in the heart, liver, spleen, lung and kidney 8 h, 24 h, and 7 days after the injection. Their distribution was histologically studied at the three time points by measuring ironpositive areas (µm2) in organ sections stained with Prussian blue. The same organs were analyzed by H&E staining for any possible histopathological changes. Furthermore, biochemical indexes such as alanine amino transaminase (ALT), aspartate transaminase (AST), blood urea nitrogen (BUN) and creatinine (CREA) were also assessed at all experimental time points. Electrophoresis exhibited that the SPION-PEI could retard siRNA altogether at weight ratios above 4. MTT assay showed that SPION-PEI loaded with siRNA had low cytotoxicity. In vivo study revealed that the liver and spleen were the major sites of SPION-PEI/siRNA deposition. The iron content was significantly increased in the liver and spleen, peaking 24 h after intravenous injection and then declining gradually. No evidence was found of irreversible histopathological damage to any of the organs tested. These results suggested that most SPION-PEI/siRNA complexes were distributed in the liver and spleen, which might be the target organs of SPION-PEI/siRNA complexes. SPIONPEI/siRNA may serve as in vivo carrier for biomedical medicines.

Synthesis and biological studies of N-alkylated cyclic diamines.

Several alkyl-substituted mesocyclic diamines were synthesized, and their interaction with DNA were studied by melting-temperature measurements and the ethidium bromide (EB)-fluorescence competitive method. The supercoiled DNA hydrolytic cleavage by 1,4-dioctyl-1,4-diazepan-6-ol (4) was supported by the evidence from free-radical quenching and T4-ligase ligation. Preliminary pharmacological tests showed that only 1,4-dioctyl-1,4-diazepan-6-ol (4) had antitumor activity against HeLa cell lines in vitro.

Transcription-inhibition and antitumor activities of N-alkylated tetraazacyclododecanes.

A series of alkyl-substituted tetraazacyclododecane congeners were synthesized, and their antitumor activities towards human HeLa cells as well as their effect on the in vitro transcription with T7 RNA polymerase were investigated. A structure-activity-relationship (SAR) study identified the most-active congeners as those with medium alkyl-chain lengths. Three compounds, 5-7, were found to exhibit significant biological activities, with IC50 values towards HeLa cells in the low-micromolar range.

A water-soluble, octacationic zinc phthalocyanine as molecular probe for nucleic acid secondary structure.

The interaction between CT-DNA and the zinc phthalocyanine ZnPc (1) was studied by UV/VIS and fluorescence titration, as well as by thermal denaturation. ZnPc was found to strongly bind to CT-DNA (K(app)=7.35 x 10(5) M(-1)) in a non-intercalative mode. The photosensitized cleavage of pBR322 DNA was found to efficiently proceed via singlet-oxygen ((1)O(2)) production. Further, ZnPc (1) caused site-specific scission of guanine (G) bases around the bulge of the hairpin oligonucleotides OD1-OD3, as clearly shown by gel-electrophoresis experiments.

Three-dimensional nanographene based on triptycene: synthesis and its application in fluorescence imaging.

A novel kind of three-dimensional (3D) nanographene based on a triptycene structure bearing three hexa-peri-hexabenzocoronene (HBC) moieties was synthesized efficiently from triiodotriptycene. With the characteristic of intrinsic fluorescence, the 3D nanographene was used as a fluorescent agent for in vitro and in vivo fluorescence imaging with good antiphotobleaching ability and little toxicity.

Novel electrochemical sensor based on functionalized graphene for simultaneous determination of adenine and guanine in DNA.

A nano-material carboxylic acid functionalized graphene (graphene-COOH) was prepared and used to construct a novel biosensor for the simultaneous detection of adenine and guanine. The direct electrooxidation behaviors of adenine and guanine on the graphene-COOH modified glassy carbon electrode (graphene-COOH/GCE) were carefully investigated by cyclic voltammetry and differential pulse voltammetry. The results indicated that both adenine and guanine showed the increase of the oxidation peak currents with the negative shift of the oxidation peak potentials in contrast to that on the bare glassy carbon electrode. The electrochemical parameters of adenine and guanine on the graphene-COOH/GCE were calculated and a simple and reliable electroanalytical method was developed for the detection of adenine and guanine, respectively. The modified electrode exhibited good behaviors in the simultaneous detection of adenine and guanine with the peak separation as 0.334V. The detection limit for individual determination of guanine and adenine was 5.0×10(-8)M and 2.5×10(-8)M (S/N=3), respectively. Furthermore, the measurements of thermally denatured single-stranded DNA were carried out and the value of (G+C)/(A+T) of single-stranded DNA was calculated as 0.80. The biosensor exhibited some advantages, such as simplicity, rapidity, high sensitivity, good reproducibility and long-term stability.

DNA hydrolysis promoted by 1,7-dimethyl-1,4,7,10-tetraazacyclododecane.

Several acyclic and macrocyclic polyamines were evaluated for their ability to cleave DNA. 1,7-Dimethyl-1,4,7,10-tetraazacyclododecane (DMC) could hydrolyze double-strand DNA at a concentration of 25microM. pH 7.2 was the optimal condition to cleave DNA in the presence of DMC. Supercoiled DNA hydrolytic cleavage by DMC was supported by the evidence from free radical quenching and T4 ligase ligation.