Generation and application of anti-ouabain IgY antibodies

Ouabain is a bioactive hapten and is very difficult to be accurately quantified because of the lack of useful reagents. Furthermore, where ouabain is produced in the adrenal glands has not been identified. In this study, ouabain-BSA was generated for immunizing the laying hens to generate ouabain-specific IgY antibodies in chicken eggs. The anti-ouabain IgY antibodies were detected in eggs 1 week after the last immunization and their concentrations increased with time. The highest concentrations of anti-ouabain IgY antibodies reached at 1:10,240 for ELISA 5 weeks after immunization and maintained for 4 weeks in chicken eggs. Following PEG precipitation, an average of 8.5 mg of anti-ouabain IgY antibodies with a purity of 87.6% was achieved from a single egg. Further analysis revealed that the anti-ouabain IgY antibodies had little immunoreactivity to hydrocortisone, dexamethasone, cedilanid, and digoxin, indicating their high specificity, and the purified IgY antibodies effectively detected endogenous ouabain in the cytoplasm of cells predominately in the zona reticularis of rat and human adrenal glands, indicating their high immunoreactivity. Given that IgY has an unique structure and bioactive features, the generated anti-ouabain IgY antibodies may be used as a new reagent for accurately quantifying ouabain in biological studies.     

Aucubin modulates Bcl-2 family proteins expression and inhibits caspases cascade in H<Subscript>2</Subscript>O<Subscript>2</Subscript>-induced PC12 cells

In this study, the effect of aucubin on H₂O₂-induced apoptosis was studied by using a rat pheochromocytoma (PC12) cell line. We have analyzed the apoptosis of H₂O₂-induced PC12 cells, H₂O₂-induced apoptosis appeared to correlate with lower Bcl-2 expression, higher Bax expression and sequential activation of caspase-3 leading to cleavage of poly-ADP-ribose polymerase (PARP). Aucubin not only inhibited lower Bcl-2 expression, high Bax expression, but also modulated caspase-3 activation, PARP cleavage, and eventually protected against H₂O₂-induced apoptosis. These results indicated that aucubin can obstruct H₂O₂-induced apoptosis by regulating of the expression of Bcl-2 and Bax, as well as suppression of caspases cascade activation.     

Targeted killing effects of double CD and TK suicide genes controlled by survivin promoter on gastric cancer cell

Suicide genes such as cytosine deaminase (CD) and herpes simplex virus thymidine kinase (TK) encode products that convert nontoxic substances (prodrugs) into toxic metabolites. Studies in recent years indicated that survivin(sur) expression was associated with the biological behaviors of gastric carcinoma. In the present study, targeted killing effects of double CD and TK suicide genes controlled by survivin promoter on gastric cancer cell were investigated, the recombinant pSCT vector containing CD and TK genes driven by sur promoter was constructed and transfected into SGC-7901 cells. After adding the CCV and 5-FC, the effects of double suicide genes on cell growth, cell cycle and proliferation were determined by MTT assay and flow cytometry (FCM). The results showed that sur promoter could specifically drive the expression of double CD/TK gene in SGC-7901 cells, whereas not in the normal GES-1 cell. After using CCV and 5-FC, the growth of SGC-7901 cells was inhibited. G1 phase proportion was significantly higher in SGC-7901 cells transfected with double suicide genes than the untransfected cells. These results suggest that CD and TK double suicide genes driven by sur promoter could provide a new approach for enhancing selective suicide gene therapy of CD/5-FC for the treatment of advanced gastric carcinoma.     

Floral closure induced by pollination in gynodioecious Cyananthus delavayi (Campanulaceae): effects of pollen load and type, floral morph and fitness consequences

Background and aims

Pollination-induced floral changes, which have been widely documented in flowering plants, have been assumed to enhance the plant''s reproductive success. However, our understanding of the causes and consequences of these changes is still limited. Using an alpine gynodioecious species, Cyananthus delavayi, we investigated the factors affecting floral closure and estimated the fitness consequences of floral closure.

Methods

The timings of floral closure and fertilization were determined. The effects of pollen load, pollen type (cross- or self-pollen) and floral morph (female or perfect flower) on the occurrence of floral closure were examined. Ovule fertilization and seed production were examined to investigate the causes and consequences of floral closure. Flowers were manipulated to prevent closing to detect potential benefits for female fitness.

Key Results

Floral closure, which could be induced by a very low pollen load, occurred within 4–7 h after pollination, immediately following fertilization. The proportion of closed flowers was influenced by pollen load and floral morph, but not by pollen type. Floral closure was more likely to occur in flowers with a higher proportion of fertilized ovules, but there was no significant difference in seed production between closed and open flowers. Those flowers in which closure was induced by natural pollination had low fruit set and seed production. Additionally, seed production was not influenced by closing-prevented manipulation when sufficient pollen deposition was received.

Conclusions

The occurrence of floral closure may be determined by the proportion of fertilized ovules, but this response can be too sensitive to ensure sufficient pollen deposition and can, to some extent, lead to a cost in female fitness. These results implied that the control of floral receptivity by the recipient flowers does not lead to an optimal fitness gain in C. delavayi.     

Buffalograss decreases ramet propagation in infertile patches to enhance interconnected ramet proliferation in fertile patches

Buffalograss (Buchloë dactyloides) is known for its low-nutrient tolerance. However, in natural habitats, nutrients are usually patchily distributed. For clonal plants like buffalograss, physiological integration is an important strategy to cope with adverse environmental conditions. In order to examine how integration helps buffalograss to survive in patchy conditions, a greenhouse experiment was conducted for 91 days. Interconnected ramet pairs of stoloniferous buffalograss were planted in two partitioned same-sized containers, and subjected to identical or contrasting nutrient supply. In contrast to normally perceived resource-sharing concepts, results showed that buffalograss genets reduced production of new ramets in nutrient-poor patches promoting at the same time propagation of interconnected ramets in nutrient-rich patches. Ramets in nutrient-rich patches gained significant benefit from heterogeneous treatments, whereas nutrient-poor ramets performed even worse than in uniform low-nutrient treatment. Younger ramets developed more biomass than elder ramets with the same amounts of nutrient supply under homogeneous treatment, while elder ramets were more tolerant when nutrients were scarce. Heterogeneity had a particular strong effect on stolons and new ramet production in nutrient-rich patches. Rooted ramets in nutrient-poor patches suffered from a by-pass of nutrients to interconnected ramets on nutrient-rich substrate that probably resulted from different transpiration rates. We conclude that this resource-sharing strategy is advantageous for buffalograss to concentrate more ramets in fertile patches, and facilitate the survivorship of more buffalograss ramets in adverse environments with uneven nutrient supply.     

一氧化氮在淋巴管收缩中的作用

淋巴管收缩是淋巴循环的动力学基础,对于维持循环系统稳态发挥重要作用.生物活性分子一氧化氮(NO)的周期性变化参与了淋巴管生理状态下的收缩、舒张以及张力调节.NO通过提高cAMP、cGMP水平激活PKA和PKG,既可引起淋巴管平滑肌细胞(LSMC)膜超极化、降低肌浆网IP3活性,从而降低LSMC细胞内Ca2+浓度;亦可通过活化肌球蛋白轻链磷酸酶降低LSMC的钙敏感性,最终降低淋巴管收缩性.通过调控淋巴管收缩过程中NO的生成与释放,有可能成为治疗或干预淋巴障碍性疾病的新靶点之一.     

An instructive role of donor macrophages in mixed chimeras in the induction of recipient CD4(+)Foxp3(+) Treg cells

The immune regulatory function of macrophages (M?s) in mixed chimeras has not been determined. In the present study, with a multi-lineage B6-to-BALB/c mixed chimeric model, we examined the ability of donor-derived splenic M?s in the induction of regulatory T cells (Treg). B6 splenic M?s from mixed chimeras induced significantly less cell proliferation, more IL-10 and TGF-β, and less IL-2 and IFN-γ productions of CD4(+) T cells from BALB/c mice than naive B6 M?s did, whereas they showed similar stimulatory activity to the third part C3H CD4(+) T cells. Importantly, highly purified donor F4/80(+)CD11c(-) M?s efficiently induced recipient CD4(+)Foxp3(+) Treg cells from CD4(+)CD25(-)Foxp3(-) T cells. Furthermore, donor M?s of mixed chimeras produced more IL-10 and less IFN-γ than those of naive mice when cultured with BALB/c but not the third party C3H CD4(+) T cells. Induction of recipient CD4(+) Treg cells by donor M?s was significantly blocked by anti-IL-10, but not by anti-TGF-β mAb. Therefore, donor M?s have the ability to induce recipient CD4(+)Foxp3(+) Treg cells in a donor antigen-specific manner, at least partially, via an IL-10-dependent pathway. This study for the first time showed that, in mixed allogeneic chimeras, donor M?s could be specifically tolerant to recipients and gained the ability to induce recipient but not the third party Foxp3(+) Treg cells. Whether this approach is involved in transplant immune tolerance needs to be determined.     

The plant growth-promoting rhizobacterium Bacillus cereus AR156 induces systemic resistance in Arabidopsis thaliana by simultaneously activating salicylate- and jasmonate/ethylene-dependent signaling pathways

Bacillus cereus AR156 is a plant growth-promoting rhizobacterium that induces resistance against a broad spectrum of pathogens including Pseudomonas syringae pv. tomato DC3000. This study analyzed AR156-induced systemic resistance (ISR) to DC3000 in Arabidopsis ecotype Col-0 plants. Compared with mock-treated plants, AR156-treated ones showed an increase in biomass and reductions in disease severity and pathogen density in the leaves. The defense-related genes PR1, PR2, PR5, and PDF1.2 were concurrently expressed in the leaves of AR156-treated plants, suggesting simultaneous activation of the salicylic acid (SA)- and the jasmonic acid (JA)- and ethylene (ET)-dependent signaling pathways by AR156. The above gene expression was faster and stronger in plants treated with AR156 and inoculated with DC3000 than that in plants only inoculated with DC3000. Moreover, the cellular defense responses hydrogen peroxide accumulation and callose deposition were induced upon challenge inoculation in the leaves of Col-0 plants primed by AR156. Also, pretreatment with AR156 led to a higher level of induced protection against DC3000 in Col-0 than that in the transgenic NahG, the mutant jar1 or etr1, but the protection was absent in the mutant npr1. Therefore, AR156 triggers ISR in Arabidopsis by simultaneously activating the SA- and JA/ET-signaling pathways in an NPR1-dependent manner that leads to an additive effect on the level of induced protection.