Tropomyosin from tilapia (Oreochromis mossambicus) as an allergen

BACKGROUND

Tilapia is among the most common fresh water fish species raised by fish farms and can cause allergic reactions upon ingestion.

OBJECTIVE

To investigate important allergens in Tilapia (Oreochromis mossambicus).

METHODS

Allergens were detected using immunoblotting. An important allergen was purified to homogeneity by reversed-phase High Pressure Liquid Chromatography and characterized by enzyme linked immunosorbent assay (ELISA), competitive ELISA, Mass spectrometry (MS), circular dichroism measurements and differential scanning calorimetry.

RESULTS

By immunoblotting using sera from 10 patients with confirmed tilapia allergy, we identified a number of allergens with apparent molecular weights 114 to 17 kD. All patients produced IgE against a 32 kD allergen, Ore m 4, which was identified by MS as tropomyosin (TM). IgE binding of the pure protein was confirmed by immunoblotting, ELISA and ELISA inhibition. cDNA from tilapia tropomyosin (TM) was sequenced and compared with TMs from other species. The tilapia TM showed 53.5% homology to TM from shrimp. Homology was much higher to human TM isoform 5 (87.7%).

CONCLUSION AND CLINICAL RELEVANCE

TMs are the major allergens in allergy to crustaceans. Auto-antibodies against human TM isoform 5 have been implicated as a causative agent in inflammatory bowel disease (IBD). Intriguingly, six of the 10 tilapia allergic patients had also been diagnosed with IBD, corroborating a connection between allergy and IBD. To our knowledge, this is the first report of tropomyosin from vertebrates as an allergen.

Novel EDA p.Ile260Ser mutation linked to non-syndromic hypodontia

Hypodontia, a tooth developmental disease, can affect chewing and pronunciation. Mutations in the ectodysplasin-A (EDA) gene can lead to both X-linked hypohidrotic ectodermal dysplasia (XLHED) and non-syndromic hypodontia (NSH). However, the mechanism by which these 2 related but different disorders are caused by the distinct mutations in EDA is unknown. In this study, we identified a novel missense mutation (c.779 T>G) in a Chinese family with NSH via a direct sequencing approach. This mutation results in an Ile260Ser substitution in the tumor necrosis factor (TNF) homology domain. Homology modeling suggests that this alteration may induce a conformational change in the hydrophobic center of the TNF homology domain. Furthermore, by exploring systematic 3D conformation analysis and calculation of residue relative solvent accessibility (RSA) for all the reported mutated amino acid sites on EDA's TNF homology domain, we found that the site mutations at the interior may be linked to XLHED, while those at the surface are more likely to be associated with NSH. These findings may aid in the discovery of unidentified functionally significant mutation sites in the EDA gene and provide a new way to clarify the mechanisms by which the XLHED and NSH phenotypes arise from mutations in the same gene.

The feasibility of using magnetic nanoparticles modified as gene vector

OBJECTIVE

To evaluate the feasibility of using magnetic nanoparticles (MNPs) as gene vector and the effect of magnetic field on efficiency of transfection.

METHODS

Magnetic nanoparticles were prepared by controlling some chemical reaction parameters through a partially reduction precipitation method with ferric chloride aqueous solution as precursor material. The surface of particles was modified by polyethyleneimine (PEI) agents. The appearance, the size distribution, structure and phase constitute of MNPs were characterized by Transmission electron microscope (TEM), X-ray diffraction (XRD); the potential of absorbing DNA of MNPs was analysed by electrophoresis. Transfection was determined by delivering reporter gene, PGL2-control encoding luciferase, to different cell lines using MNPs-PLL as vector. The effect of magnetic field on the efficiency of transfection was determined using Nd-Fe-B permanent magnet.

RESULTS

Foreign gene could be delivered to various cell lines by MNPs-PLL and expressed with high efficiency but the transfection efficiency and time course varied in the different cell lines studied. Magnetic field could enhance the efficiency of transfection by 5-10 fold.

CONCLUSION

MNPs- PLL can be used as a novel non-viral gene vector in vitro, which offers a basis for gene delivery in vivo.

Implications of cellular senescence in tissue damage response, tumor suppression, and stem cell biology

Cellular senescence is characterized by an irreversible cell cycle arrest that, when bypassed by mutation, contributes to cellular immortalization. Activated oncogenes induce a hyperproliferative response, which might be one of the senescence cues. We have found that expression of such an oncogene, Akt, causes senescence in primary mouse hepatoblasts in vitro. Additionally, AKT-driven tumors undergo senescence in vivo following p53 reactivation and show signs of differentiation. In another in vivo system, i.e., liver fibrosis, hyperproliferative signaling through AKT might be a driving force of the senescence in activated hepatic stellate cells. Senescent cells up-regulate and secrete molecules that, on the one hand, can reinforce the arrest and, on the other hand, can signal to an innate immune system to clear the senescent cells. The mechanisms governing senescence and immortalization are overlapping with those regulating self-renewal and differentiation. These respective control mechanisms, or their disregulation, are involved in multiple pathological conditions including fibrosis, wound healing, and cancer. Understanding extracellular cues that regulate these processes may enable new therapies for these conditions.

Generation and analysis of genetically defined liver carcinomas derived from bipotential liver progenitors

Hepatocellular carcinoma is a chemoresistant cancer and a leading cause of cancer mortality; however, the molecular mechanisms responsible for the aggressive nature of this disease are poorly understood. In this study, we developed a new liver cancer mouse model that is based on the ex vivo genetic manipulation of embryonic liver progenitor cells (hepatoblasts). After retroviral gene transfer of oncogenes or short hairpin RNAs targeting tumor suppressor genes, genetically altered liver progenitor cells are seeded into the liver of otherwise normal recipient mice. We show that histopathology of the engineered liver carcinomas reveals features of the human disease. Furthermore, representational oligonucleotide microarray analysis (ROMA) of murine liver tumors initiated by two defined genetic hits revealed spontaneously acquired genetic alterations that are characteristic for human hepatocellular carcinoma. This model provides a powerful platform for applications like cancer gene discovery or high-throughput preclinical drug testing.

[The development and application of computer-aided bone histomorphometry system]

The aim of this study is to develop a Computer-aided Bone Histomorphometry System. The method is based on the Micro-graphical Digital System composed of microscope, digital camera, computer and related programs. The methodology was developed to measure the basic data on each image of visual field of hard bone tissue with computer-assistance. Following this, the parameters of bone volume, bone structure and bone metabolism were calculated based on the standardization of bone histomorphometry. Such method has been used in the experimental and clinical studies of osteoporosis to predict the fracture risk and evaluate the drug effect.

trans-3,4-dihydroxy-anti-1,2-epoxy-1,2,3,4-tetrahydrodi- benz[a,j]acridine involvement in dibenz[a,j]acridine DNA adduct formation in mouse skin consistent with Ha-ras mutation patterns in tumors

Dibenz[a,j]acridine (DBA), is a N-heteropolycyclic aromatic environmental carcinogen found in complex combustion mixtures. The major route of DBA metabolic activation is reportedly through the trans-3,4-dihydroxy-3,4-dihydroDBA (DBA-3,4-DHD). The present studies were undertaken to determine the role of trans-3,4-dihydroxy-anti-1,2-epoxy-1,2,3,4-tetrahydroDBA (DBADE) in DBA activation pathway(s), the DNA bases involved in the binding of DBA to DNA, and whether the adducts produced are consistent with the mutation pattern in the Ha-ras gene. DBA (300 microg) or 50 microg synthesized (+/-)-DBADE was applied to the back of female Hsd:ICR(Br) mice. The mice were sacrificed 48 h later, and skin DNA was isolated, hydrolyzed, and analyzed with (32)P-postlabeling. Of the four adducts produced in vivo, adduct 1 was the major adduct for DBA (>50%) and adduct 2 was the major adduct for DBADE (89%). After the reaction of (+/-)-DBADE with purine nucleotides or calf thymus (CT) DNA in vitro, 100% of the DBADE-2'-dAMP adducts and 94% of DBADE-CT DNA adducts were chromatographically identical on TLC with adduct 2 and 86% of the DBADE-2'-dGMP adducts were chromatographically consistent with adduct 1 by (32)P-postlabeling. Papillomas were induced on the backs of mice by a single application of 0.2 micromol of DBA followed by twice-weekly application of 12-o-tetra-decanoylphorbol-13-acetate (TPA, 2 microg) for 24-26 weeks. Skin carcinomas were induced by twice weekly applications of DBA (0.1 micromol) on the backs of mice. A to T and G to T transversions were found in codons 12, 13, and 61 of the Ha-ras gene in the treated mouse skin carcinoma and papilloma DNA. The mutational spectra in the Ha-ras gene are consistent with the DNA binding of DBA to dG or dA in vivo. Thus, this research has indicated that DBADE plays an important role in DBA metabolic activation and DNA binding in mouse skin, and an alternative pathway through a bis-dihydrodiol-epoxide of DBA may also be involved.

[The computer-aided measurement of medullary canal in proximal femur]

This study was conducted to search the law of the parameters of medullary canal section shape in proximal femur. The methods of image-processing and taper-curve-fit mathematics were adopted in the acquisition of data and parameters. Computer-aided method and manual method were employed to measure 10 samples of section shape in proximal femur. The results showed that no significant difference was seen between the computer-aided method and manual method(P> 0.05). This approach could reduce man-made errors and process mass samples automatically by computer.

The therapeutic effects of Sheng Jing Zhong Zi Tang in treating male infertility

Eight-seven cases of male infertility due to spermatopathy were treated with Sheng Jing Zhong Zi Tang (SJZZT [symbol: see text]) for 1-3 courses. The total effective rate was 95.40% (83/87). 56.32% (49/87) of their spouses got pregnant and the semen quality was markedly improved (P < 0.01). The results showed that the decoction could dual-directionally regulate the levels of follicle-stimulating hormone (FSH), prolan B luteinizing hormone (LH), testosterone (T), and cortisol (C).

The effects of a binary mixture of benzo(a)pyrene and 7H-dibenzo(c,g)carbazole on lung tumors and K-ras oncogene mutations in strain A/J mice

Polycyclic aromatic hydrocarbons (PAH) and N-heterocyclic aromatic hydrocarbons (NHA) are environmental pollutants formed during the incomplete combustion of organic materials. Benzo(a)pyrene (BaP) and 7H-dibenzo(c,g)carbazole (DBC) are well-characterized representatives of the PAH and NHA classes of compunds, respectively. Both are demonstrated carcinogens that frequently co-occur in environmental mixtures. This preliminary study was conducted to investigate the effects of a binary mixture of BaP and DBC on lung carcinogenicity in the strain A/J mouse as manifested by tumor development and mutations in the K-ras gene. Male A/J mice were administered the following single intraperitoneal dose (mg/kg) combinations of BaP and DBC dissolved in a 0.2-mL volume of tricaprylin--10 DBC:10 BaP; 2 DBC:10 BaP; 2 DBC:100 BaP; and 10 DBC: 100 BaP, and each of the compounds alone at the same doses. Mice were sacrificed 8 months after carcinogen treatment and lung tumor multiplicity and K-ras mutations determined (high-dose combination). The combination of DBC and BaP produced fewer tumors than the sum of all tumors produced by each compound acting alone. The frequency of tumors with K-ras mutations was also less in a sample of the 10 DBC:100 BaP treatment group than in the same-dose, single compound-treated animals. The dominant mutations produced by BaP and DBC were expressed in tumors from animals treated with the mixture.

[Pressure influence on mRNA expression and protein synthesis of inducible nitric oxide synthetase in bovine trabecular meshwork cell]

OBJECTIVE

To investigate the inducible nitric oxide synthetase (iNOS) mRNA expression and protein synthesis in bovine trabecular meshwork cell and discuss the possible effects of nitric oxide (NO) in the development of glaucoma.

METHODS

20 mm Hg, 40 mm Hg, 60 mm Hg and 80 mm Hg pressure were respectively added on cultured trabecular cells of new born bovine. No pressure group was set as the control. The changes of iNOS mRNA and protein in trabecular meshwork cells under different pressures were demonstrated qualitatively and quantitatively by in situ hybridization and nicotinamide-adenine dinucleotide phosphate diaphorase (NADPH-d) histochemical assay.

RESULTS

The expression of iNOS mRNA and its protein synthesis became higher and higher as the pressure was increased. There was weak iNOS mRNA expression in the control and 20 mm Hg groups, and no significant difference between them. 40 mm Hg and 60 mm Hg groups had a statistical difference from the control group. And 80 mm Hg group had a very significant difference from the control group. There was no difference between 40 mm Hg and 60 mm Hg groups, but they had significant difference from 80 mm Hg group. NADPH-d histochemical assay showed almost the same results except that there was significant difference between 40 mm Hg and 60 mm Hg groups.

CONCLUSIONS

Pressure can evoke the expression of iNOS mRNA, and the nitric oxide thus produced can be one of the causes of trabecular meshwork destruction, that may induce or aggravate glaucoma.