Rapid identification of glycerophospholipids from RAW264.7 cells by UPLC/ESI -QTOF-MS

The study aims to develop a rapid, sensitive ultra-performance liquid chromatography coupled with an electrospray ionization quadruple time-of-flight tandem mass spectrometry (UPLC/Q-TOF-MS) analytical method for identifying glycerophospholipids (GPLs) from RAW264.7 cells. A total of 78 GPLs including 22 phosphatidylethanolamines (PEs), 49 phosphatidylcholines (PCs), four phosphatidylglycerols, one phosphatidylinositol and two unknown GPLs were identified. PC (14:0/16:1), PC (14:0/16:0), PE (0:0/20:3), PE (22:5/0:0) and PE (22:3/0:0) were identified for the first time. The UPLC/Q-TOF-MS method is suitable for targeting analysis of GPLs from RAW264.7 cells, which allows us to find out new GPLs compositions related to inflammatory diseases and to explain their pharmacological roles in inflammatory process.

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.

[Effect of the methylation enzyme inhibitors of 5-aza-2-deoxycytidine on the TGF-beta/smad signal transduction pathway in human keloid fibroblasts]

OBJECTIVE

To investigate the effect of 5-aza-2-deoxycytidine on the TGF-beta/smad signal transduction pathway in human keloid fibroblasts (KFSs).

METHODS

Firstly, immunohistochemical method was used to detect the positive expression rate of phospho-smad2 and phospho-smad3 in the specimens of 15 cases of keloid and 15 cases of normal skin. The keloid fibroblasts were cultured in vitro with 5-aza-2-deoxycytidine(experimental group) or with DMEM (control group). The effect of 5-aza-2-deoxycytidine on the cell cycle and apoptosis of fibroblasts was analysed with flow cytometry ( FCM). Transforming growth factor (TGF)-beta1, Smad7, phospho-smad2 and phospho-smad3 were analyzed by Western Blot, and Immunofluorescence.

RESULTS

It was found that the positive expression of phospho-smad2 and phospho-smad3 in keloid were higher than those in normal skin. The FCM showed that the proportion of cells in G0/G1 stage was increased, and so does the proportion of apoptosis cells in keloid fibroblasts intervened by 5-aza-2-deoxycytidine. The expression of TGF-beta1, phospho-smad2 and phospho-smad3 protein were significantly suppressed while the expression of smad7 protein increased in keloid fibroblasts with 5-aza-2-deoxycytidine. In addition, 5-aza-2-deoxycytidine reversed phosphorylation and nuclear translocation of smad2 and smad3.

CONCLUSIONS

5-aza-2-deoxycytidine, methylase inhibitors, inhibits cell proliferation and promotes apoptosis of KFSs, which may be associated with the suppression of TGF-beta/smad signal pathway.

Genetic analysis of mate discrimination in Drosophila simulans

Courtship is an elaborate behavior that conveys information about the identity of animal species and suitability of individual males as mates. In Drosophila, there is extensive evidence that females are capable of evaluating and comparing male courtships, and accepting or rejecting males as mates. These relatively simple responses minimize random sexual encounters involving subpar conspecific males and heterospecific males, and over generations can potentially select novel physical and behavioral traits. Despite its evolutionary and behavioral significance, little is still known about the genes involved in mating choice and how choices for novel males and females arise during evolution. Drosophila simulans and Drosophila sechellia are two recently diverged species of Drosophila in which females have a preference for conspecific males. Here we analyzed a total of 1748 F2 hybrid females between these two species and found a small number of dominant genes controlling the preference for D. simulans males. We also mapped two redundant X-linked loci of mating choice, Macho-XA and Macho-XB, and show that neither one is required for female attractiveness. Together, our results reveal part of the genetic architecture that allows D. simulans females to recognize, mate, and successfully generate progenies with D. simulans males.

[Expression and significance of DNMT1 in human keloid fibroblast]

OBJECTIVE

To investigate the expression and significance of DNA methyltransferase 1 (DNMT1) in different parts and formation time of keloid fibroblasts.

METHODS

Specimen were collected from fifty-three patients with keloid. The keloids were grouped according to formation time. Immunohistochemistry was used to assay the expression of DNMT1 in normal skin, invasive part, proliferative part and aged part. RT-PCR was adopted to assay the expression of DNMT1 mRNA in each group.

RESULTS

DNMT1 is mainly distributed in the nucleus of fibroblasts. The expression of DNMT1 protein and DNMTl mRNA in keloid (72%) is higher than that in normal skin fibroblasts (8%) (P = 0.001). The expression rate of DNMT1 protein and DNMT1 mRNA in shorter formation time group (100%, Score:10.47 +/- 1.85) is higher than a longer formation time group (45%,Score: 7.71 +/- 1.80) (P = 0.007). The expression rate of DNMT1 protein and DNMT1 mRNA in the invasive part of keloid (100%, Score: 10.47 +/- 1.85) is higher than the proliferative part (78%, Score: 6.63 +/- 1.75) and aged part (38%, Score: 5.53 +/- 1.55) (P = 0.001).

CONCLUSIONS

DNMT1 plays an important role in keloid. The expression of DNMT1 tends to decrease along with the increase of the formation time in keloid. It is also related to the part of keloid. DNMT1 plays an important role in the process of keloid growth and is closely related to infiltrative growth in keloid.