Isolation and characterization of a transferrin binding protein from rat plasma

A transferrin binding protein was isolated from normal rat placenta and from iron-deficient rat plasma using a human transferrin affinity column. The yield of the isolated pure protein from iron-deficient rat plasma was about 0.5 micrograms/ml plasma. The major protein had a molecular mass of 85 kDa and contained carbohydrate. Reduction with mercaptoethanol did not change the molecular mass of the plasma transferrin binding protein whereas the native placental transferrin receptor of 180 kDa was reduced to 90 kDa. The transferrin binding protein reacted with both monoclonal and polyclonal antibodies raised against rat transferrin receptor. Immunoblotting of both normal and iron deficient rat plasma showed that the transferrin binding protein had a molecular mass of 85 kDa. In vitro digestion of purified rat placental transferrin receptor and red blood cells with trypsin provided an identical peptide profile, suggesting that the transferrin binding protein in rat plasma is derived from proteolysis of the extracellular portion of the transferrin receptor of the erythroid tissues.     

Electrophoretic mobility and immunoblot analysis of the outer membrane proteins of Aeromonas hydrophila, A. sobria and A. caviae.

The outer membrane profiles of three species of the genus Aeromonas were examined by means of SDS-PAGE and immunoblotting to identify species-specific polypeptides and antigens which could presumably be applied to differentiate Aeromonas spp. at the species or subspecies level. Profiles on an 11% discontinuous SDS-PAGE showed common band sharing at the 52 kD position. Species-specific bands for the three strains could also be detected. Immunoblots using heterologous LPS-adsorbed polyclonal antisera revealed demarcated common and uncommon antigens within the three species. Outer membrane preparations were immunoblotted against whole cell polyclonal antisera. The previously documented host pathogenicity of A. sobria correlated well with the immunoblots which showed antigenicity, especially due to the LPS, when compared with the other two species.     

Alternative functional relationships between ELF field exposure and possible health effects: report on an expert workshop.

If exposure to 60 Hz fields poses risks to public health, the relationship between exposure and risk may involve something other than the product of field strength and time. Such alternative possible relations, or "effects functions," are of great interest to epidemiologists, engineers, risk analysts, and regulators. A structured survey and workshop were used to explore whether leading researchers in bioelectromagnetics share similar views about alternative possible effects functions. Substantial agreement was found about several effects functions in a few specific contexts such as calcium-ion efflux and cell signalling, and biosynthesis pathways. No significant agreement emerged in many other contexts. No effects function possibilities were ruled out. Further effort of this sort was judged unlikely to yield greater consensus until more complete scientific understanding becomes available. However, a series of structured workshops on research planning and priority setting were judged to hold great potential for useful results.     

Isolation of a novel human alpha (1,3)fucosyltransferase gene and molecular comparison to the human Lewis blood group alpha (1,3/1,4)fucosyltransferase gene. Syntenic, homologous, nonallelic genes encoding enzymes with distinct acceptor substrate specificities.

Biochemical and genetic evidence indicates that the human genome may encode four or more distinct GDP-fucose:beta-D-N-acetylglucosaminide 3-alpha-L-fucosyltransferase (alpha(1,3)fucosyltransferase) activities. Genes encoding two of these activities have been previously isolated. These correspond to an alpha(1,3/1,4)fucosyltransferase thought to represent the human Lewis blood group locus and an alpha(1,3)fucosyltransferase expressed in the myeloid lineage. We report here the molecular cloning and expression of a third human alpha(1,3)fucosyltransferase gene, homologous to but distinct from the two previously reported human fucosyltransferase genes. When expressed in transfected mammalian cells, this gene determines expression of a fucosyltransferase capable of using N-acetyllactosamine to form the Lewis x epitope, and alpha(2,3)sialyl-N-acetyllactosamine to construct the sialyl Lewis x moiety. This enzyme shares 91% amino acid sequence identity with the human Lewis blood group alpha(1,3/1,4)fucosyltransferase, yet exhibits only trace amounts of alpha(1,4)fucosyltransferase activity. Polymerase chain reaction analyses were used to demonstrate that the gene is syntenic to the Lewis locus on chromosome 19. These analyses also excluded the possibility that this DNA segment represents an allele of the Lewis locus that encodes alpha(1,3)fucosyltransferase but not alpha(1,4)fucosyltransferase activity. These results are consistent with the hypothesis that this gene encodes the human "plasma type" alpha(1,3)fucosyltransferase, and suggest a molecular basis for a family of human alpha(1,3)fucosyltransferase genes.     

The catalase-peroxidase of Mycobacterium intracellulare: nucleotide sequence analysis and expression in Escherichia coli.

The activation of catalase genes in response to oxidative stress may contribute to the intracellular survival of mycobacteria. In this report, the nucleotide sequence of a mycobacterial catalase gene is described. The deduced protein sequence of this Mycobacterium intracellulare gene (MI85) was 60% identical to the Escherichia coli hydroperoxidase I (HPI) protein, 59% identical to the Salmonella typhimurium (HPI) catalase, and 47% identical to a Bacillus stearothermophilus peroxidase. The MI85 protein, expressed in E. coli, has also been shown to have peroxidase and catalase activities. Furthermore, Southern blot hybridizations, which demonstrated that a MI85 gene probe hybridizes with chromosomal DNA from thirteen different strains of mycobacteria, suggest that this catalase-peroxidase gene is prevalent in the mycobacterial genus. The availability of catalase gene probes should permit an evaluation, at the molecular level, of the role of catalase in mycobacterial pathogenesis.     

Stoichiometry of the aldehyde fuchsin staining reaction for proteins.

Model systems of agar films containing known concentrations of bovine serum albumin and alpha-chymotrypsinogen were stained with aldehyde fuchsin after oxidation with acidified permanganate solution. These films were scanned in a scanning microphotometer to determine the mean extinction and the total extinction of predetermined areas. Results indicate that the dye binds quantitatively to the proteins. Blocking the acidic side groups of the proteins inhibited the binding of the dye. The degree of inhibition was directly related to the number of sulfhydryl or carboxyl groups that were blocked. Similar blocking reactions performed on the type "A" neurosecretory cells of the pars intercerebralis of the insect Oncopeltus fasciatus gave similar results. Analysis of the dye protein complexes gave a dye to acidic group ratio of 1:1.     

Some observations on the division of five species of commensalic ciliates in relation to water propulsion

A study was made to understand whether there is any correlation between the physiological or morphogenetic activities of commensalic ciliates and the cycles of water propulsion of their hosts. Commonly occurring species ciliates. Boveria teredinidi, Trichodina balakrishnia, Nucleocorbula adherens, Thigmozoon fencheli and Nyctotherus marina from the hosts Teredo furcifera and Nausitora hedleyi were used. The total number and the individuals in division for each species of ciliates were noticed. The results obtained indicate that there is no correlation between the activities of these ciliates and cycles of water propulsion. The data were statistically analysed. It was found that shipworms below 8 mm. in size were not infected with these ciliates. This shows that infection takes place, not from the parent's body but from the outside water after a definite period of growth of the host. An increase in number of commensals in relation with the increase in size of the host was observed. There is a decline in numbers in the oldest hosts. The number of dividing individuals also follows the same pattern of occurrence.     

Preliminary Observations Pertaining to Polyadenylation of Rhinovirus RNA

Human rhinovirus type 14 contained polyadenylated RNA. Virus growth in HeLa cells was inhibited by cordycepin or polyuridilic acid and stimulated by polyadenylic acid. Polyadenylic acid also reversed cordycepin inhibition of virus-induced cytopathology of infected HeLa cells.