Transforming growth factor-alpha directly augments histidine decarboxylase and vesicular monoamine transporter 2 production in rat enterochromaffin-like cells

For the production and vesicle storage of histamine, Enterochromaffin-like (ECL) cells express histidine decarboxylase (HDC) and vesicular monoamine transporter 2 (VMAT2). Although HDC and VMAT2 show dynamic changes during gastric ulcer healing, the control system of their expression has not been fully investigated. In the present study, we investigated the effect of transforming growth factor-alpha (TGF-alpha) and proinflammatory cytokines on HDC and VMAT2 expression in rat ECL cells. Time course changes in the expression of TGF-alpha during the healing of acetic acid-induced ulcers were studied. EGF receptor (EGFR) expression was also examined in ECL cells, whereas the direct effects of TGF-alpha and proinflammatory cytokines on HDC and VMAT2 expression in ECL cells were investigated using in vivo and in vitro models. During the process of ulcer healing, expression of TGF-alpha mRNA was markedly augmented. Furthermore, EGFR was identified in isolated ECL cells. TGF-alpha stimulated HDC and VMAT2 mRNA expression and protein production and also increased histamine release from ECL cells. Selective EGFR tyrosine kinase inhibitor tyrphostin AG1478 almost completely inhibited HDC and VMAT2 gene expression induced by TGF-alpha in vivo and in vitro. During gastric mucosal injury, TGF-alpha was found to stimulate ECL cell functions by increasing HDC and VMAT2 expression.     

RNA aptamers selected against the receptor activator of NF-kappaB acquire general affinity to proteins of the tumor necrosis factor receptor family

The receptor activator of NF-κB (RANK) is a member of the tumor necrosis factor (TNF) receptor family and acts to cause osteoclastgenesis through the interaction with its ligand, RANKL. We isolated RNA aptamers with high affinity to human RANK by SELEX. Sequence and mutational analysis revealed that the selected RNAs form a G-quartet conformation that is crucial for binding to RANK. When the aptamer binding to RANK was challenged by RANKL, there was no competition between the aptamer and RANKL. Instead, the formation of a ternary complex, aptamer–RANK–RANKL, was detected by a spin down assay and by BIAcore surface plasmon resonance analysis. Moreover, the selected aptamer efficiently bound to other TNF receptor family proteins, such as TRAIL-R2, CD30, NGFR as well as osteoprotegerin, a decoy receptor for RANK. These results suggest that the selected aptamer recognizes not the ligand-binding site, but rather a common structure conserved in the TNF receptor family proteins.     

RGA protein associates with a TRPV ion channel during biosynthesis and trafficking

TRPV ion channels transduce a range of temperature stimuli. We proposed that analysis of the protein-protein interactions made by TRPV2 might give insight into the key issues surrounding this channel. These issues include the potential functional significance of TRPV2 in non-sensory tissues, the molecules involved in transducing its activation signal(s) and the mechanism by which its trafficking to the cell surface is regulated. Here we describe the interaction of TRPV2 channel with the RGA gene product. RGA is a four-transmembrane domain, intracellularly localized protein. RGA associates with TRPV2 in a rat mast cell line that is a native context for both proteins. The interaction between TRPV2 and RGA is transient and occurs intracellularly. RGA does not accompany TRPV2 to the cell surface. Formation of the TRPV2/RGA complex is dependent upon a cellular glycosylation event, suggesting that RGA may play a chaperone or targeting role for TRPV2 during the maturation of the ion channel protein. These data record a novel protein-protein interaction for TRPV2 and provide a foundation for future study of the potential regulatory contribution of RGA to TRPV2 function.     

Antimitotic activity and reversal of breast cancer resistance protein-mediated drug resistance by stilbenoids from Bletilla striata

Eight stilbenoids, 1-(p-hydroxybenzyl)-4,8-dimethoxyphenanthrene-2,7-diol (1), 2,7-dihydroxy-1,3-bis(p-hydroxybenzyl)-4-methoxy-9,10-dihydrophenanthrene (2), 4,7-dihydroxy-1-(p-hydroxybenzyl)-2-methoxy-9,10-dihydrophenanthrene (3), 3,3'-dihydroxy-2',6'-bis(p-hydroxybenzyl)-5-methoxybibenzyl (4), 3',5-dihydroxy-2-(p-hydroxybenzyl)-3-methoxybibenzyl (5), blestriarenes B (6) and C (7), and blestrianol A (8) have been isolated by the guidance of inhibitory effect of tubulin polymerization from the tubers of Bletilla striata (Orchidaceae). Among them, both of bisbenzyls 4 and 5 inhibited the polymerization of tubulin at IC(50) 10muM, respectively. Furthermore bisbenzyl 4 potentiated the cytotoxicity of SN-38 in BCRP-transduced K562 (K562/BCRP) cells.     

Comparison of defence and performance traits between one widespread clone and native populations in a major invasive plant species

Aim

The success of invasive species in their introduced range is often assumed to result from evolutionary changes in defence and growth traits, or as a response to more favourable conditions. The latter is assumed particularly for species exhibiting low, or even no, sexual reproduction in the introduced range.

Location and Methods

Here, we compared Japanese (native range) and French (introduced range) populations of Fallopia japonica under common growth conditions in a glasshouse. We measured height, aboveground and belowground mass, stem stiffness, leaf toughness and secondary metabolites found in hydroalcoholic extracts of rhizomes of F. japonica, as well as the competitive response of Rubus caesius (a co‐occurring native species in the invaded range) in the presence of F. japonica from both ranges.

Results

Aboveground biomass, height, stem stiffness and composition of secondary metabolites were not significantly different between the two ranges, showing that increased aboveground vigour observed in situ in France is probably the result of a plastic response following the release of abiotic or biotic constraints from the native range. On the other hand, belowground mass, effect on R. caesius, and leaf toughness were all higher in French populations, suggesting increases in competitive ability and defence mechanisms. These differences between France and Japan may be explained either by post‐introduction evolution or by the introduction in Europe, in nineteenth century, of an exceptionally vigorous clone (pre‐adaptation).

Main conclusions

Our results provide evidence that the high vigour of this major invasive species in its introduced range is probably due to both a response to more favourable conditions and rapid evolution.

     

Auxin-Induced Expansion Growth of Cells and Protoplasts of Yeast

Using an auxin-responsive mutant of Sacchairomyces ellipsodeus, expansion growth of cells caused by auxin was studied especially in comparison with that of protoplasts.

• 1 Indole-3-acetic acid induced detectable cell expansion growth in 3 hours in a buffered simple solution where no cell division occurred.
• 2 The auxin-induced expansion growth was inhibited by an antiauxin, trans-cinnamic acid.
• 3 Actinomycin D, chloramphenicol and cycloheximide inhibited the auxin-induced cell expansion growth.
• 4 Protoplasts did not expand in response to auxin under the condition where intact cells did.
• 5 The stability of protoplasts was not changed by the low auxin concentration (20 mg/1) which induced cell expansion.
• 6 High concentrations (100–1000 mg/1) of auxin caused protoplasts to burst even under an osmotically stable condition.

     

Loss‐of‐function of ASPARTIC PEPTIDASE NODULE‐INDUCED 1 (APN1) in Lotus japonicus restricts efficient nitrogen‐fixing symbiosis with specific Mesorhizobium loti strains

The nitrogen‐fixing symbiosis of legumes and Rhizobium bacteria is established by complex interactions between the two symbiotic partners. Legume Fix^– mutants form apparently normal nodules with endosymbiotic rhizobia but fail to induce rhizobial nitrogen fixation. These mutants are useful for identifying the legume genes involved in the interactions essential for symbiotic nitrogen fixation. We describe here a Fix^– mutant of Lotus japonicus, apn1, which showed a very specific symbiotic phenotype. It formed ineffective nodules when inoculated with the Mesorhizobium loti strain TONO. In these nodules, infected cells disintegrated and successively became necrotic, indicating premature senescence typical of Fix^– mutants. However, it formed effective nodules when inoculated with the M. loti strain MAFF303099. Among nine different M. loti strains tested, four formed ineffective nodules and five formed effective nodules on apn1 roots. The identified causal gene, ASPARTIC PEPTIDASE NODULE‐INDUCED 1 (LjAPN1), encodes a nepenthesin‐type aspartic peptidase. The well characterized Arabidopsis aspartic peptidase CDR1 could complement the strain‐specific Fix^– phenotype of apn1. LjAPN1 is a typical late nodulin; its gene expression was exclusively induced during nodule development. LjAPN1 was most abundantly expressed in the infected cells in the nodules. Our findings indicate that LjAPN1 is required for the development and persistence of functional (nitrogen‐fixing) symbiosis in a rhizobial strain‐dependent manner, and thus determines compatibility between M. loti and L. japonicus at the level of nitrogen fixation.     

Monoclonal Antibody #5-2-26 Recognizes the Phosphatase-Sensitive Epitope of Rabies Virus Nucleoprotein

We prepared monoclonal antibodies (MAbs) against the rabies virus N protein, among which one antibody (MAb 5-2-26) was shown to lack reactivity with the phosphatase-treated N protein. The MAb was able to recognize the sodium dodecyl sulfate (SDS)-denatured N protein. The MAb did not recognize the N-protein analogues produced in Escherichia coli (E. coli), indicating that the N-gene products were not normally processed in E. coli after translation. On the other hand, the MAb reacted normally with N-gene products produced in COS-7 cells, but not with those produced in the presence of K-252a (a protein kinase inhibitor of a broad spectrum). The MAb displayed weak cross-reactivity with the Triton-insoluble network structures composed of several components, while another phosphoprotein (M1) of the virus was not recognized at all. These results suggest that MAb 5-2-26 preferentially recognizes a phosphatase-sensitive linear epitope of N protein, which may enable further investigations to be conducted on the mechanism of N-protein phosphorylation and its role(s) in virus replication.