Structural investigation of the capsular polysaccharide of Klebsiella serotype k23

Klebsiella K23 capsular polysaccharide has been investigated by the techniques of hydrolysis, methylation, Smith degradation-periodate oxidation, and base-catalysed degradation, either on the original or the carboxyl-reduced polysaccharide. The structure was found to consist of a tetrasaccharide repeating-unit, as shown below. The anomeric configurations of the sugar residues were determined by ₁H-and ¹³C-n.m.r. spectroscopy on the original and degraded polysaccharides.

     

Analysis of antigenic determinants of structural polypeptides of avian type C tumor viruses.

Radioimmunoassays were developed for the 19,000, 15,000, and 12,000 molecular weight polypeptides of avian myeloblastosis virus and for the 19,000 and 12,000 polypeptides of RAV-0, a subgroup E avian tumor virus. Each polypeptide was shown to possess both group- and type-specific antigenic determinants, in contrast to the 27,000 mol wt polypeptide, which contained only group-specific determinants. The corresponding low-molecular-weight polypeptides of subgroup A, B, and E viruses were shown to be immunologically indistinguishable. The findings that low-molecular-weight polypeptides of subgroup C and D viruses reacted very differently in immunoassays for the respective polypeptides of avian myeloblastosis virus or RAV-0 suggest that subgroups C and D may have evolved differently form subgroups A, B, and E.     

Antigenic determinants of the 70,000 molecular weight glycoprotein of woolly monkey type C RNA virus.

The 70,000 molecular weight glycoprotein (gp70) of a type-C RNA virus originally isolated from a woolly monkey has been partially purified and immunologically characterized. Evidence that this viral protein is viral coded was derived from studies showing its antigenic properties to be unaltered by virus passage in cells of different species. A broadly reactive competition immunoassay was developed utilizing antiserum prepared against feline leukemia virus to precipitate 125I-labeled woolly monkey virus gp70. Gibbon and woolly viruses, as well as feline and several mouse type-C viruses, all reacted with equal efficiency in this assay. In contrast, an endogenous virus of the baboon failed to cross-react, suggesting that viruses of this latter group are less immunologically related to the others. In a homologous competition immunoassay for the woolly viral glycoprotein, the woolly virus was readily distingusihed from otherwise colsely related viruses of gibbon apes. These findings demonstrate the pronounced type-specific antigenic dterminants possessed by this viral protein. The antigenic determinants of gp70 responsible for neutralization have also been investigated.     

Changes in Prokaryote and Eukaryote Assemblages Along a Gradient of Hydrocarbon Contamination in Groundwater

Groundwater biota are particularly sensitive to environmental perturbations such as groundwater contamination. The diversity of prokaryotic and eukaryotic biota has been examined along a gradient of chlorinated hydrocarbon (CHC) contamination in the Botany Sands, an urban coastal sand-bed aquifer (Sydney, Australia). Molecular techniques were used to analyze the richness and composition of prokaryote and eukaryote assemblages using 16S and 18S rDNA, respectively. Taxon richness did not change significantly along the gradient for either prokaryotes or eukaryotes; however, significant shifts in assemblage composition were evident for both groups. Assemblage changes were most strongly correlated with concentrations of the major CHC, cis-1,2-dichloroethene, but the concentrations of a number of the contaminants were also correlated, making it difficult to infer if effects were due to any particular contaminant. The presence of cis-1,2-dichloroethene and other secondary ethenes suggests in situ breakdown of the primary CHCs via natural attenuation. The current focus of management of the Botany aquifer is to stop the contaminant plume reaching the adjoining estuary. This approach is clearly justified given the changes evident in the microbial assemblages in the groundwater, which are a likely consequence of the contamination.     

Eph receptors and their ligands: Promising molecular biomarkers and therapeutic targets in prostate cancer

Although at present, there is a high incidence of prostate cancer, particularly in the Western world, mortality from this disease is declining and occurs primarily only from clinically significant late stage tumors with a poor prognosis. A major current focus of this field is the identification of new biomarkers which can detect earlier, and more effectively, clinically significant tumors from those deemed “low risk”, as well as predict the prognostic course of a particular cancer. This strategy can in turn offer novel avenues for targeted therapies. The large family of Receptor Tyrosine Kinases, the Ephs, and their binding partners, the ephrins, has been implicated in many cancers of epithelial origin through stimulation of oncogenic transformation, tumor angiogenesis, and promotion of increased cell survival, invasion and migration. They also show promise as both biomarkers of diagnostic and prognostic value and as targeted therapies in cancer. This review will briefly discuss the complex roles and biological mechanisms of action of these receptors and ligands and, with regard to prostate cancer, highlight their potential as biomarkers for both diagnosis and prognosis, their application as imaging agents, and current approaches to assessing them as therapeutic targets. This review demonstrates the need for future studies into those particular family members that will prove helpful in understanding the biology and potential as targets for treatment of prostate cancer.