Emerging Role for Exosomes in the Progress of Stem Cell Research.

Exosomes are small secretory vesicles that are involved in intercellular communication. Exosomes are secreted by many types of cells and exert important functions in plasma-membrane exchange as well as the transport of bioactive substances, such as proteins, messenger ribonucleic acids (mRNAs), micro ribonucleic acids (miRNAs) and organelles. Exosomes may regulate physiological processes by altering gene regulatory networks or epigenetic recombination. Recent studies have shown that exosomes secreted by stem cells can effectively transport proteins, mRNAs and miRNAs and play important roles in the regulation of tissue regeneration. This report reviews current progress in exosome studies as well as their emerging roles in stem cell research and potential clinical use.

[Expression of multiepitope antigenic gene of Toxoplasma gondii in transgenic tomatoes].

OBJECTIVE: To obtain the transgenic tomato plant expressed multiepitope antigenic gene of Toxoplasma gondii (Tg-MAG). METHODS: Tg-MAG under the control of E35S promoter, E35S-E81.1 chimeric promoter and E8 2.2 promoter in the plant expression vectors was transferred into the tomato cotyledons and hypocotyls via Agrobacterium-mediated T-DNA transformation. The candidate buds were obtained and elongated by kanamycin resistant screening. After further rooting selection, the selected tomato lines were trained and transplanted to soil and grown in a greenhouse till blossoming and bearing fruit. The transgenic tomato plants were identified using PCR, RT-PCR and Western blotting. RESULTS: Tg-MAG was introduced into the transgenic plant genomic DNA and transcribed correctly at expected size 360 bp identified by PCR and RT-PCR. Western blotting results indicated that the recombinant Tg-MAG from 8 transgenic lines, expressed in tomato fruits at expected size 11900, 2 of them showed strong reaction band with HRP labeled McAb K7H3 against the major surface antigen 1( SAG1) of T. gondii tachyzoites. CONCLUSION: Tg-MAG transgenic tomato lines were obtained. Tg-MAG recombinant protein with good immune activity was expressed successfully in transgenic tomato fruits.