Inhibition of arabidopsis hypocotyl elongation by jasmonates is enhanced under red light in phytochrome B dependent manner

Jasmonates are phytohormones derived from oxygenated fatty acids that regulate a broad range of plant defense and developmental processes. In Arabidopsis, hypocotyl elongation under various light conditions was suppressed by exogenously supplied methyl jasmonate (MeJA). Moreover, this suppression by MeJA was particularly effective under red light condition. Mutant analyses suggested that SCF^COI1-mediated proteolysis was involved in this function. However, MeJA action still remained in the coi1 mutant, and (+)-7-iso-JA-L-Ile, a well-known active form of jasmonate, had a weaker effect than MeJA under the red light condition, suggesting that unknown signaling pathway are present in MeJA-mediated inhibition of hypocotyl elongation. EMS mutant screening identified two MeJA-insensitive hypocotyl elongation mutants, jasmonate resistance long hypocotyl 1 (jal1) and jal36, which had mutations in the phytochrome B (PHYB) gene. These analyses suggested that inhibition of hypocotyl elongation by jasmonates is enhanced under red light in phyB dependent manner.     

Induction of human malignant T-lymphoblastic cell lines MOLT-3 and jurkat by 12-O-tetradecanoylphorbol-13-acetate: Biochemical,physical, and morphological characterization

The process of induction of human malignant T-lymphoblastic cell line MOLT-3 by the phorbol ester 12-O-tetradecanoylphorbol-13-acetate (TPA) was examined. It was found that the induction process by TPA, which included increase in cells with receptors to sheep red blood cells (E-rosette positive-E⁺) and decrease in the levels of the marker enzyme terminal deoxynucleotidyl transferase (TdT) was not affected by the presence of DNA synthesis inhibitor arabinofuranosylcytosine (Ara-C). The exposure time to TPA required to elicit these changes was found to be short, in the order of 1 hour or less. The kinetics of the increase in E⁺ cells, decrease in the levels of TdT in these cells, or decrease in the ability to proliferate as measured by colony formation were similar with exposure to TPA for 1, 6, 24, or 96 hours. We have examined the effect of antitumor promoter compounds on their ability to block induction of MOLT-3 cells by TPA. Results indicated that none of these compounds, dexamethasone, antipain, retinoic acid, and L-1-tosylamide-2-phenylethylchloromethyl ketone (TPCK), was effective in reducing the number of E⁺ cells induced by TPA. Examination of three other leukemic T-cell lines indicated that, in addition to MOLT-3, the leukemic T-cell line Jurkat also responded to TPA, whereas two other leukemic T-cells lines CCRF-CEM and CCRF-HSB-2 did not. Certain physical and morphological changes were also observed after stimulation of MOLT-3 cells and Jurkat cells by TPA. We found that, following the addition of TPA, the cell volumes of MOLT-3 cells decreased from an average of 1150 μm³ to about 500 μm³, whereas those of Jurkat were reduced to about 700 μm³ from 1100 μm³. Electron microscopic studies of these lymphoblasts also revealed that after treatment with TPA the induced cells were generally smaller in size with increase in the density of the nuclear materials and condensation of the chromatin structures.     

PRRX1 promotes malignant properties in human osteosarcoma

Paired related homeobox 1 (PRRX1) is a marker of limb bud mesenchymal cells, and deficiency of p53 or Rb in Prrx1-positive cells induces osteosarcoma in several mouse models. However, the regulatory roles of PRRX1 in human osteosarcoma have not been defined. In this study, we performed PRRX1 immunostaining on 35 human osteosarcoma specimens to assess the correlation between PRRX1 level and overall survival. In patients with osteosarcoma, the expression level of PRRX1 positively correlated with poor prognosis or the ratio of lung metastasis. Additionally, we found PRRX1 expression on in 143B cells, a human osteosarcoma line with a high metastatic capacity. Downregulation of PRRX1 not only suppressed proliferation and invasion but also increased the sensitivity to cisplatin and doxorubicin. When 143B cells were subcutaneously transplanted into nude mice, PRRX1 knockdown decreased tumor sizes and rates of lung metastasis. Interestingly, forskolin, a chemical compound identified by Connectivity Map analysis using RNA expression signatures during PRRX1 knockdown, decreased tumor proliferation and cell migration to the same degree as PRRX1 knockdown. These results demonstrate that PRRX1 promotes tumor malignancy in human osteosarcoma.     

TectoRNP: self‐assembling RNAs with peptide recognition motifs as templates for chemical peptide ligation

TectoRNA, an artificial RNA with self‐assembling ability, has been employed as a structural platform for RNA nanotechnology and RNA synthetic biology. In this study, tectoRNA was applied as a specific template for chemical peptide ligation. On the basis of a self‐assembling tectoRNA, we designed and constructed a template RNA that facilitates peptide ligation depending on controlled dimer formation. Two RNA‐binding peptides were recognized by two peptide‐binding RNA motifs embedded in the template RNA, and chemical ligation was promoted because of the entropic effect of Mg²⁺‐dependent dimerization. In a series of biochemical analyses, we determined the relationship between the structures of the tectoRNA‐based templates and the extent of acceleration in peptide ligation. Copyright © 2012 European Peptide Society and John Wiley & Sons, Ltd.     

Flight capabilities and feeding habits of silphine beetles: are flightless species really “carrion beetles”?

We determined the flight capabilities and feeding habits of adults of nine silphine beetle species and illustrated their relationship. We examined the silphine beetles for the presence or absence of flight muscles and estimated their feeding habits by comparing the carbon and nitrogen stable isotope ratios for them with those of necrophagous nicrophorine species and carnivorous carabine species. Three species (Silpha longicornis, S. perforata and Phosphuga atrata) completely lacked individuals with flight muscles, and one species (Eusilpha japonica) showed flight muscle dimorphism. Stable isotope analysis suggested that these species were carnivores, mainly feeding on soil invertebrates. Most flight species showed higher isotopic ratios than the flightless species. Some of them have isotopic ratios close to those of the nicrophorine species, suggesting that these species mainly feed on vertebrate carcasses. Flightless silphine species would have limited ability to search for patchy and unpredictable carcass resources. Further studies are necessary to understand the adaptive evolution of flight capability and the feeding habits in this group.     

Reversible Changes in Conformation of the 23-kDa Protein of Photosystem II and Their Relationship to the Susceptibility of the Protein to a Proteinase from Photosystem II Membranes

An aspartic proteinase was partially purified from PSII membranesof spinach. The 23-kDa protein of PSII was resistant to theproteinase when in its native form but became susceptible uponmodification by p-chloromercuriphenylsulfonic acid (pCMPS),upon incubation at pH 3, and upon incubation in dilute SDS.Conformational changes caused by pCMPS seemed to be restrictedto a localized region since the modified protein reconstitutedthe water-oxidizing complex with slightly less efficiency ascompared with the untreated protein. Under the three proteolyticconditions, cleavage occurred at the Asn-58-Leu-59 bond, suggestingthat the protein underwent similar conformational changes ineach case. Dithiothreitol, dialysis at pH 7, and neutral detergentssuppressed the facilitative effects of pCMPS, pH 3, and SDSon proteolysis, respectively. With the reversible changes insusceptibility, reversible changes in circular dichroism ofthe protein also occurred at 200–208 nm. These observationsindicate that the conformational changes are reversible andthe renaturation of the substrate was associated with the suppressionof the susceptibility. These results suggest that the scissilebond becomes reversibly exposed and susceptible to the proteinasein response to environmental changes. (Received November 23, 1994; Accepted February 7, 1995)     

Cellular interaction against autologous tumor cells between IL-2-cultured lymphocytes and fresh peripheral blood lymphocytes in patients with breast cancer given immuno-chemotherapy

In patients with Stage II or III breast cancer and in patients with liver metastases from breast cancer, we examined cellular interaction in the cytotoxicity against autologous tumor cells by interleukin-2(IL-2)-cultured lymphocytes (CL) and fresh peripheral blood lymphocytes (FPBL) treated with immunochemotherapy including OK-432 and cyclophosphamide. In flow cytometric analysis, CD8 + CD11b+ and CD16+ cells significantly decreased after immuno-chemotherapy in both groups of patients. A protocol study in Stage II or III breast cancer patients showed suppressive activity of FPBL on the cytotoxic activity of CL in 3/9 of the non-treatment group but no suppressive activity and enhancing activity in 3/7 in the immuno-chemotherapy group. Moreover, in 19 patients with liver metastases from breast cancer treated with immuno-chemotherapy including adoptive immunotherapy, FPBL in 6/19 showed enhancing activity, and in 8/19 suppressive activity in the lysis of autologous tumor cells. In assaysin vitro using autologous and allogeneic tumor cells, FPBL showed a partial specificity in cellular interaction against autologous tumor cells. CD4-depleted FPBL inhibited cytotoxicity of CL, while CD8-depleted FPBL enhanced cytotoxicity of CL in patients with liver metastases. These results suggest that immuno-chemotherapy eliminates the suppressive population in FPBL and may induce tumor regression if combined with adoptive immunotherapy using CL.Abbreviations IL-2 interleukin-2 - CL IL-2-cultured lymphocytes - FPBL fresh peripheral blood lymphocytes - AIT adoptive immunotherapy