Purification of an allergenic protein fraction from wheat grain.

An allergenic protein fraction was isolated from wheat gluten by ion exchange and gel filtration chromatography. On sodium dodecyl sulphate gel electrophoresis the molecular mass of the protein was found to be 65 kDa. By Western blotting it was confirmed that the 65 kDa protein was the major allergenic fraction causing dermatitis herpetiformis (DH) and it contained glutamic acid and proline as the major amino acids.

Metabolic enzymes as potential drug targets in Plasmodium falciparum.

Plasmodium falciparum causes the most severe form of malaria that is fatal in many cases. Emergence of drug resistant strains of P. falciparum requires that new drug targets be identified. This review considers in detail enzymes of the glycolytic pathway, purine salvage pathway, pyrimidine biosynthesis and proteases involved in catabolism of haemoglobin. Structural features of P. falciparum triosephosphate isomerase which could be exploited for parasite specific drug development have been highlighted. Utility of P. falciparum hypoxanthine-guanine-phosphoribosyltransferase, adenylosuccinate synthase, dihydroorotate dehydrogenase, thymidylate synthase-dihydrofolate reductase, cysteine and aspartic proteases have been elaborated in detail. The review also briefly touches upon other potential targets in P. falciparum.

Low dose radiation--a curse or a boon?

The increased use of nuclear technology has created fear in the minds of people regarding its possible adverse effects on living systems. This fear is heightened by press reports of nuclear fallouts and of high levels of natural background radiation in geographical areas in a number of countries. The International Commission on Radiological Protection and the United Nations Scientific Committee on the Effects of Atomic Radiation estimate the risk of cancer from high dose exposure to be 4.5% to 7.1% per sievert depending on the projection model used. However, when the exposure is to low dose background radiation, the available data does not show an increased risk. This is possibly due to the effectiveness of the inherent repair capacity of the living cell. These observations have given rise to the 'hormesis' hypothesis. Low dose radiation has in fact been found to be immunostimulatory and this is now being exploited as a possible treatment modality in cancer patients.

Adrenal carcinoma with reactive plasmacytosis.

An 18 year old boy presented with anaemia, congestive cardiac failure and a 'renal mass'. Preoperative and post-operative investigations demonstrated "reactive plasmacytosis" with antibodies directed against a non-functioning adrenal carcinoma. Existing literature on reactive plasmacytosis and anti-tumour antibodies is summarised.

Spectroscopic studies on the interaction of bilirubin with symmetrical alkyl diamines.

The interactions of symmetrical alkyldiamines with bilirubin-IX α have been examined in dichloromethane and dioxane solutions, by visible region difference spectroscopy and florescence methods. In dioxane solutions a clear difference is observed between the complexes of the shorter chain diamines (number of spacer methylene groups (n ≤ 4)) and the longer chain diamines (n ≥ 6). The variations in spectral features with diamine chain length are less pronounced in dichloromethane. The spectroscopic results are consistent with the occurrence of distinct bilirubin conformations depending upon the solvent and the geometry of the interacting receptor. Based on molecular modelling two conformations are proposed. A ‘ridge-tile’ model similar to that observed in crystals is favoured for binding to the longer diamines, while a ‘quasi-cyclic’ structure is preferred for interaction with the short chain diamines.

Interactions of the channel forming peptide alamethicin with artificial and natural membranes.

Alamethicin and related α-aminoisobutyric acid peptides form transmembrane channels across lipid bilayers. This article briefly reviews studies on the effect of alamethicin on lipid phase transitions in lipid bilayers and on mitochondrial oxidative phosphorylation. Fluorescence polarization studies, employing 1,6-diphenyl-1,3,5-hexatriene as a probe, suggest that alamethicin fluidizes lipid bilayers below the phase transition t-emperature, but has little effect above the gel-liquid crystal transition point. Alamethicin is shown to function as an uncoupler of oxidative phosphorylation in rat liver mitochondria. The influence of alamethicin on mitochondrial respiration is modulated by the phosphate ion concentration in the medium. Classical uncoupling activity is evident at low phosphate levels while inhibitory effects set in at higher phosphate concentrations. Time-dependent changes in respiration rates following peptide addition are rationalized in terms of alamethicin interactions with mitochondrial membrane components.

Fluorescence polarization as a tool to study lectin-sugar interaction.

The binding of Ricinus communis agglutinin and Abrus agglutinin to 4-methylumbelliferyl β-D-galactopyranoside was studied by equilibrium dialysis, fluorescence quenching and fluorescence polarization. The number of binding sites and the association constant value obtained by fluorescence polarization for both Ricinus communis agglutinin and Abrus agglutinin are in close agreement with those obtained by the other methods. This indicates the potential of ligand-fluorescence polarization measurements in the investigation of lectin-sugar interactions.

Metal binding to pyridoxal derivatives. An NMR study of the interaction of Eu(III) with pyridoxal phosphate and pyridoxamine phosphate.

The solution conformations of pyridoxal-5'-phosphate and pyridoxamine- 5'-phosphate have been investigated using Eu(III) as a nuclear magnetic resonance shift probe. Binding of Eu(III) to pyridoxal phosphate results in the formation of two complexes, at the phosphate group and the o-hydroxy-aldehyde moiety, which are in slow exchange on the nuclear magnetic resonance time-scale. The lanthanide-induced pseudo contact shifts calculated using the McConnell-Robertson equation (J. Chem. Soc. (1950), 22, 1561) are in good agreement with the experimentally observed values for both pyridoxal phosphate and pyridoxamine phosphate and lead to a family of closely related conformations.