Monoclonal antibody to shiga toxin 1, which blocks receptor binding and neutralizes cytotoxicity

A monoclonal antibody, 5-5B, which neutralizes Shiga toxin 1 (Stx1) cytotoxicity of Escherichia coli, was constructed. An epitope analysis indicated that Asn55 in Stx1 B subunit was an important residue. This result and our previous results using an anti-Stx2 monoclonal antibody indicate that the region around the cysteine residue of the disulfide bond might be important for the neutralization of Stx cytotoxicity, making it a potential vaccination candidate.     

Enhancer-trapping system for somatic embryogenesis in carrot

Somatic embryogenesis in the carrot was used to model zygotic embryogenesis because the spatial and temporal changes in somatic and zygotic embryogenesis are quite similar. To establish an enhancer-trapping system for somatic embryogenesis in the carrot, we constructed 2 enhancer-trap vectors (pETVs) using the GUS reporter gene with a minimal promoter. We also constructed several positive control vectors (pPCVs) using the CaMV 35S promoter. These are models in which pETVs are inserted near a native enhancer region in correct or reverse orientation. First, we tested whether these vectors could be used as enhancer-trap vectors using transgenic hairy root of tobacco. Histochemical GUS assays revealed that pETVs could be used as enhancer-trap vectors, even when the reporter gene in the pETVs was inserted near the native enhancer. Subsequently, we examined the availability of pETVs in somatic embryogenesis in the carrot. The constructed vector was activated in transgenic carrot embryogenic cells at high frequency (64%). This suggests that the enhancer-trapping vector is suitable as a carrot somatic embryogenesis system.     

Numerical simulation for electrochemical cultivation of iron oxidizing bacteria

A numerical simulation model was constructed for electrochemical cultivation of iron oxidizing bacterium, Thiobacillus ferrooxidans, based on Monod's dual limitation equation. In this model, two limiting factors were examined, low supply of Fe(II) ion and dissolved oxygen, from empirical viewpoints. The simulation model was constructed taking into consideration the energy balance based on the amount of the electronic flow from the electrode to bacteria via an iron ion, and then to oxygen. The model consisted of a logarithmic bacterial growth phase during the first three days, followed by a plateau and growth limitation thereafter. The predicted results were in agreement with the actual growth under electrochemical cultivation. It was predicted the growth limiting factor would be changed from insufficient supply of Fe(II) ions to that of oxygen by decreasing the value of oxygen transfer constant K, which correlated with the aeration rate. The optimum aeration rate was determined for the ideal electrochemical cultivation. The algorithm described here can be used in any electrochemical cultivation by modifying the parameters for each system.     

Synthesis of an ether-linked alkyl 5a-carba-beta-D-glucoside,a 5a-carba-beta-D-galactoside,a 2-acetamido-2-deoxy-5a-carba-beta-D-glucoside,and an alkyl 5a'-carba-beta-lactoside

For the purpose of providing biologically stable building blocks for the biocombinatorial synthesis using a living cell, some ether-linked alkyl 5a-carba-beta-D-glycoside primers were prepared. The key step of the synthesis was coupling of 1-bromo-n-alkanes with the 1-OH unprotected derivatives of 5a-carba-sugar analogues of D-glucose, D-galactose, and 2-acetamido-2-deoxy-D-glucose (N-acetyl-D-glucosamine), in DMF in the presence of sodium hydride. Alternatively, alkyl carba-lactoside was synthesized by incorporation of a 5a-carba-beta-D-galactose residue into the 4-position of dodecyl beta-D-glucopyranoside. A strong and specific inhibition of beta-galactosidase (K(i) 0.67 microM, bovine liver) was found for dodecyl 5a-carba-beta-D-galactopyranoside.     

Three-dimensional structure of the inclusion complex between phloridzin and beta-cyclodextrin

The inclusion of phloridzin into beta-cyclodextrin was studied as a model of molecular recognition in membranes. Effects on 1H NMR spectra and NOE correlational peaks between phloridzin and beta-cyclodextrin were observed in the complex. Strong NOEs were observed between hydrogens of a phenol group in phloridzin and beta-cyclodextrin. The three-dimensional structure of the inclusion complex between phloridzin and beta-cyclodextrin was simulated with distance constraints estimated by the intensity of NOE peaks using the DADAS90 programs. Two inclusion possibilities were suggested-the large rim of beta-cyclodextrin as an entrance of the inclusion and the small rim of beta-cyclodextrin as the entrance. In both cases, the phenol group of phloridzin was included in the hydrophobic space of beta-cyclodextrin.     

Suppression of antibody production by TNF-related apoptosis-inducing ligand (TRAIL)

TNF-related apoptosis-inducing ligand (TRAIL), a type II membrane protein belonging to the TNF family, induces apoptotic cell death in various types of tumor cells. However, little is known about its pathological and physiological functions in the immune system. In this study, we showed that administration of neutralizing anti-TRAIL mAb markedly increased serum auto-Ab levels, particularly of IgG1 subclass, in autoimmune-prone C3H/HeJ gld/gld mice without affecting lymphocytosis and lymphocytes populations. In an experimental system where TNP-specific Ab production was induced by immunization with TNP-modified syngeneic B lymphoma cells, expression of TRAIL on these cells significantly reduced TNP-specific Ab production, especially of IgG1 subclass, without affecting T cell priming. These results suggest a new role for TRAIL in the suppression of Ab production.     

Expression of Hex homeobox gene during skin development: Increase in epidermal cell proliferation by transfecting the Hex to the dermis

A number of homeobox genes have been found to be expressed in skin and its appendages, such as scale and feather, and appear to be candidates for the regulation of the development of these tissues. We report that the proline-rich divergent homeobox gene Hex is expressed during development of chick embryonic skin and its appendages (scale and feather). In situ hybridization analysis revealed that, during development of the skin, a transient expression of the Hex gene was observed. While the expression of Hex in the dermis was closely correlated with proliferation activity of epidermal basal cells, that in the epidermis was related to a suppression of epidermal differentiation. When dermal fibroblasts were transfected with Hex, stimulation of both DNA synthesis and proliferation of the epidermal cells followed by two-fold scale ridge elongation and increase in epidermal area was observed during culture of the skin, whereas epidemal keratinization was not affected. This is the first study to demonstrate that Hex is expressed during development of the skin and its appendages and that its expression in the dermal cells regulates epidermal cell proliferation through epithelial mesenchymal interaction.