Search

Although nonspecific lipid transfer proteins (nsLTPs) are widely expressed during plant defence responses to pathogens, their functions and regulation are not fully understood. In this article, we report the isolation of a cDNA for the new nsLTP, StLTPa7, from cultivated potato (Solanum tuberosum) infected with Ralstonia solanacearum. The cDNA was predicted to encode a type 1 nsLTP containing an N-terminal signal sequence and possessing the characteristic features of nsLTPs. A phylogenetic analysis showed that the encoded amino acid sequence of the nsLTP was similar to those of other previously reported plant nsLTPs, which contain a putative calmodulin-binding site consisting of approximately 12 highly conserved amino acid residues. The expression of the StLTPa7 gene was studied during the early stages of potato-R. solanacearum interaction using real-time quantitative polymerase chain reaction (qRT-PCR) and Northern analyses, and a complex calcium (Ca2+)-associated pattern of expression was observed with the following features: (i) transcripts of the StLTPa7 gene were systemically up-regulated by infection with R. solanacearum; (ii) the StLTPa7 gene was stimulated by salicylic acid, methyl jasmonate, abscisic acid and Ca2+; (iii) qRT-PCR showed that, during the early stage of R. solanacearum infection, nsLTP transcripts accumulated over a time course that paralleled that of Ca2+ accumulation, detected using environmental scanning electron microscopy and energy-dispersive X-ray (EDAX) spectrometry; and (iv) the Ca2+ channel blocker, ruthenium red, partially blocked R. solanacearum-induced StLTPa7 expression. This report represents the first use of EDAX analysis to establish a synchrony between Ca2+ accumulation and nsLTP expression in response to potato-R. solanacearum interactions. Collectively, these results suggest that StLTPa7 may be a pathogen- and Ca(2+)-responsive plant defence gene.

To study the effect of adoptive transfer of paternal antigen-tolerant T cells on recipient reactive T cells, CBA/JxDBA/2 mating was recruited as an abortion-prone model, and CBA/JxBALB/c mating as a successful pregnancy model. The abortion-prone CBA/J females mated with DBA/2 males were injected intraperitoneally with rat anti-mouse CD80 and CD86 mAb or rat isotype IgG at day 4 after gestation (time of implantation). The purified T cells were obtained from spleen of the pregnant CBA/J mice using magnetic beads at day 9 after gestation and labeled with CFSE in vitro. The CFSE-labeled T cells were intravenously injected into other CBA/J females mated with DBA/2 males at day 4 after gestation. The proliferation of recipient splenocytes in response to DBA/2 stimulator cells was evaluated at day 9 after gestation in vitro, and the expressions of intracellular cytokines and costimulatory molecules in CFSE +/- T cells were analyzed by flow cytometry. The results showed that adoptive transfer of either paternal antigen-tolerant T cells or T cells from BALB/c-mated CBA/J mice significantly suppressed the proliferation of recipient splenocytes in response to DBA/2 stimulator cells and resulted in lower frequency of cells positive for IL-2, IFN-gamma, CD28 and higher frequency of IL-10,CTLA-4-producing cells in both CFSE+ CD3+ population and CFSE- CD3+ population compared with adoptive transfer of T cells from isotype IgG-treated CBA/J mice, whereas the frequency of IL-4-producing cells did not appear significant change. Our findings suggest that paternal antigen-tolerant T cells transferred in recipient not only function as antigen-specific suppresser cells but also disable the recipient reactive T cells, which co-suppresses maternal rejection to the allogeneic fetus, thus resulting in the decrease of the embryo resorption rate of the abortion-prone mice to that of the normal pregnancy mice.

To investigate the role of MEK/ERK1/2 signal pathway in the regulation of cyclosporin A(CsA) -induced titin expression in human trophoblast cells. With RT-PCR and Western Blot, We examined the titin expression level of human trophoblast cells treated with different concentrations of CsA for various duration, then detected total ERK1/2 and phosphorated ERK1/2 level with Western Blot, and observed effect of U0126 on transcription of titin mRNA in human trophoblast cells stimulated by cyclosporin A. It was found that CsA could activate ERK1/2 in time-dependent and dosage-dependent manner, and induced titin to be expressed in human trophoblast cells. U0126, a MEK inhibitor, inhibited the transcription of titin in dosage-dependent manner. These results indicated that MEK/ERK1/2 signal pathway may play an important role in the expression of titin in human trophoblast induced by cyclosporin A.

Objective: To study effect of blockade of costimulatory signal CD(80), CD(86) at the early stage of gestation on the maternal peripheral immuno-tolerance status to paternal antigen and pregnant outcome of murine abortion-prone model., Methods: The experiments were performed in two groups, using CBA/J x BALB/c matings as the normal pregnancy model and CBA/J x DBA/2 matings as the abortion-prone model. The pregnant CBA/J mice which had mated with DBA/2 or BALB/c male mice respectively were injected intraperitoneally with purified rat isotype IgG or purified rat anti-mouse CD(80), CD(86) mAb at day 4 of gestation (time of implantation). The proliferation response of maternal splenic immuno-competent cells to paternal splenic cells as stimulator was analyzed by one way mixed lymphocyte reaction, and IL-2 production was assayed by ELISA to evaluate the immuno-tolerance of maternal peripheral immuno-competent cells to paternal antigen at day 9 of gestation. The embryo resorption rate was counted at day 14 of gestation., Results: In the CBA/J x DBA/2 matings, anti-CD(80), CD(86) mAb administered at day 4 of gestation reduced significantly the embryo resorption rate, and induced a significantly lower proliferation response and IL-2 production by maternal splenic immuno-competent cells to paternal antigen compared with rat isotype IgG., Conclusions: In vivo blockade of costimulatory signal at day 4 of gestation can induce the immuno-tolerance of maternal peripheral immuno-competent cells to paternal antigen, thus leading the embryo resorption rate of the abortion-prone model to that of normal pregnancy model.