Characterization of the amine oxidase involved in the growth of Trichosporon cutaneum X4 on ethylamine as source of carbon,nitrogen and energy

The amine oxidase from Trichosporon cutaneum X₄ grown on ethylamine as carbon, nitrogen and energy source was purified to near homogeneity. The purified enzyme showed the highest resistance to heat of any amine oxidase hitherto characterized from a yeast (half-life at 62°C, 14 min). Measurement of kinetic parameters as a function of carbon chain length showed results typical of a benzylamine oxidase. Both non-denaturing- and sodium dodecyl sulphate-polyacrylamide gel electrophoresis showed multiple bands, and dimethyl suberimidate cross-linking studies revealed that the enzyme consisted of multimers of two polypeptide chains of M_r respectively 19,000 and 26,000. The smallest structure to show activity probably contained two of each kind of subunit.Abbreviation SDS sodium dodecyl sulphate     

Glycosylation of the self-recognizing Escherichia coli Ag43 autotransporter protein

Glycosylation is a common modulation of protein function in eukaryotes and is biologically important. However, in bacteria protein glycosylation is rare, and relatively few bacterial glycoproteins are known. In Escherichia coli only two glycoproteins have been described to date. Here we introduce a novel member to this exclusive group, namely, antigen 43 (Ag43), a self-recognizing autotransporter protein. By mass spectrometry Ag43 was demonstrated to be glycosylated by addition of heptose residues at several positions in the passenger domain. Glycosylation of Ag43 by the action of the Aah and TibC glycosyltransferases was observed in laboratory strains. Importantly, Ag43 was also found to be glycosylated in a wild-type strain, suggesting that Ag43-glycosylation may be a widespread phenomenon. Glycosylation of Ag43 does not seem to interfere with its self-associating properties. However, the glycosylated form of Ag43 enhances bacterial binding to human cell lines, whereas the nonglycosylated version of Ag43 does not to confer this property.     

A distinct subset of podoplanin (gp38) expressing F4/80+ macrophages mediate phagocytosis and are induced following zymosan peritonitis

Macrophages are important tissue resident cells that regulate the dynamics of inflammation. However, they are strikingly heterogeneous. During studies looking at podoplanin (gp38) expression on stromal cells in the murine spleen and peritoneal cavity we unexpectedly discovered that podoplanin was expressed on a subset of F4/80⁺ macrophages; a subset which we have termed fibroblastic macrophages (FM). These cells function as phagocytes in vitro as measured by bead mediated phagocytosis assays. FM also exist at high frequency in the peritoneal cavity and in zymosan induced peritonitis in vivo. These FM represent a unique subgroup of F4/80⁺ macrophages and their presence in the inflamed peritoneum suggests that they play a role in zymosan induced peritonitis.     

Development of the Minimum Information Specification for In Situ Hybridization and Immunohistochemistry Experiments (MISFISHIE)

We describe the creation process of the Minimum Information Specification for In Situ Hybridization and Immunohistochemistry Experiments (MISFISHIE). Modeled after the existing minimum information specification for microarray data, we created a new specification for gene expression localization experiments, initially to facilitate data sharing within a consortium. After successful use within the consortium, the specification was circulated to members of the wider biomedical research community for comment and refinement. After a period of acquiring many new suggested requirements, it was necessary to enter a final phase of excluding those requirements that were deemed inappropriate as a minimum requirement for all experiments. The full specification will soon be published as a version 1.0 proposal to the community, upon which a more full discussion must take place so that the final specification may be achieved with the involvement of the whole community.     

Transgenic tobacco plants expressing Tarin 1 inhibit the growth of Pseudomonas syringae pv. tomato and the development of Spodoptera frugiperda

The protein Tarin 1, from Colocasia esculenta, was expressed in Nicotiana tabacum. Bioassays were done on plants expressing Tarin 1 at different levels using Spodoptera frugiperda larvae, various bacteria and fungi and the root‐knot nematode Meloidogyne javanica. It was found that S. frugiperda larvae fed on transformed plants had retarded and lower pupation, lower accumulated biomass and higher mortality rate than larvae fed on control plants. Also, Tarin 1 was found to inhibit the growth in vitro of Pseudomonas syringae pv. tomato. For Meloidogyne javanica, both relative replication and root damage were greater in control plants than in transformed plants, but the results were not statistically significant. This work illustrates the effects of plants expressing Tarin 1, on the growth and development of insects and bacteria, and shows its potential for pest management.     

HBsAg-positive chronic liver disease: inhibition of DNA polymerase activity by vidarabine.

Four patients who had chronic liver disease and were positive for hepatitis B surface antigen (HBsAg) were treated with vidarabine, a synthetic purine nucleoside that inhibits DNA polymerase activity in vitro and in vivo. Before treatment all had raised serum DNA polymerase concentrations. Three also had hepatitis B e (HBe) and were shown by electron microscopy to have hepatitis B virus (Dane) particles in their serum. In all patients 10 days'' treatment with vidarabine resulted in an immediate loss of DNA polymerase activity. In three patients the activity returned when treatment was stopped. In those three patients Dane particles and HBe antigen persisted during and after treatment; in the fourth patient, who remained negative for DNA polymerase, HBsAg titres fell. Although vidarabine inhibited virus replication, virus particles did not disappear from the blood in these patients, presumably because the particles were cleared only slowly. Similar results with interferon suggest that the virus disappears, and HBsAg titres fall, some weeks after the fall in DNA polymerase activity. Continued treatment may therefore have a sustained effect on viral replication. Whether vidarabine can permanently clear HBsAg and so arrest chronic liver disease remains to be seen, but at the very least it could reduce the spread of infection.     

Parenteral 1,25-dihydroxycholecalciferol in hepatic osteomalacia.

Despite regular long-term parenteral vitamin D2 treatment, four patients with biliary cirrhosis had multiple symptoms of bone disease and bone biopsy specimens showed osteomalacia without osteoporosis. Three patients also had a proximal myopathy. Plasma calcium values (after correction for albumin), phosphorus, magnesium, and serum 25-hydroxy-vitamin D were within normal limits. Treatment with 1,25-dihydroxy-cholecalciferol (1,25-(OH)2D3) relieved symptoms in three of the four patients and improved those in the fourth. Histological examination of bone showed improvement in all four patients, but serum and urinary biochemical changes were not pronounced. We conclude that 1,25-(0H)2D3 treatment has a beneficial effect on bone and muscle in hepatic osteomalacia, either because vitamin D 1-hydroxylation fails in biliary cirrhosis or because hepatic osteomalacia is resistant to vitamin D2 metabolites.