Undetected Component Research Articles

Characterization and biological relevance of A 29-kDa, oestrogen receptor-related protein

The properties of a monoclonal antibody (D5) that can immunoprecipitate human oestradiol receptor (ER) under some but not all conditions are described. The antibody recognises a 29-kDa serine phosphoprotein that is qualitatively and quantitatively related to ER but not other steroid receptors or binding proteins. p29 will not complex with untreated cytosol ER but, after ammonium sulphate, KCl, heat or phosphatase treatments, interaction occurs that can be detected by immunoprecipitation with D5; molybdate and GTP inhibit complex formation. In human endometrium, p29 is increased by oestrogen and decreased by progestins. IRMA and histochemical assays for p29 have been developed and applied to a large series of human breast tumours. Most, but not all ER+ tumours are p29+, whilst ER- tumours are rarely p29+ unless they are also PR+. p29 predicts for clinical response to hormone therapy. ER+ p29+ tumours have a higher response rate than the ER+ p29- tumours. We do not know if p29 is a previously undetected component of the oestradiol receptor machinery or whether it is a product of oestrogen action.

Immunological probes for oestradiol receptors in human breast tumours

Monoclonal antibodies have been prepared against a soluble oestradiol receptor (REC) preparation partially purified from human myometrium by oestradiol affinity chromatography. The antibodies were detected by their ability to immunoprecipitate receptor bound [ 125I] oestradiol. One of the antibodies (D5) has been studied in detail. It will only precipitate REC after activation by salt, heat, low pH or KCNS and will not react with nuclear RE. It will not react with androgen, progesterone or glucocorticoid receptors nor with sex hormone binding globulin; it will only combine with REC from human sources. D5 recognizes a cytoplasmic 29 kdalton protein (p29) that can be separated from both type I and II soluble oestradiol binding proteins, p29 can react with activated REC and is qualitatively and quantitatively related to REC. IRMA and histochemical methods have been developed for quantitating p29 and relating its amount to receptors in human breast tumours. With both methods, highly significant ( P < 0.001) correlations with REC but not RP have been obtained. Both methods indicate that many REC-RP+ tumours contain p29. The histochemical method detects marked cellular heterogeneity in some tumours. The function of p29 is not known. It is an REC-related antigen that may be a previously undetected component of the oestradiol receptor machinery.

Transgressive segregation for resistance to yellow rust in wheat

Crosses were made between wheat varieties Joss Cambier, Nord Desprez and Maris Bilbo, all classified as susceptible to yellow rust in field tests, and between Cappelle Desprez and Maris Huntsman, both classified as moderately and durably resistant. Selection for resistance to yellow rust among the progeny was carried out using races of Puccinia striiformis able to overcome all the known race-specific components of resistance in both parents of each cross. Lines with greater resistance than in both parents were obtained from each cross, those with greatest resistance being obtained from the cross between the moderately resistant parents. Three lines selected for resistance from the cross of Joss Cambier with Nord Desprez and one from the cross of Cappelle Desprez with Maris Huntsman, together with the parents, were tested in the field with 12 races of P. striiformis. Nord Desprez possessed a previously undetected race-specific component. The selected lines also displayed race-specific resistance, some of which was clearly related to race-specificity of the parents, and a component of resistance, greater than in both parents, that was effective against all 12 races. The possible origin and potential durability of this transgressive level of resistance is discussed. It is suggested that such transgressive resistance is more likely to be durable if it is derived from parents that have shown durable resistance.

The use of specific conductance in studies of natural waters and soil solutions / Emploi de la conductance spécifique dans les études des eaux naturelles et des solutions dans le sol

ABSTRACT Specific conductance (SC) is widely used as a measure of mineral salt concentration and a variety of models have been employed which relate SC to total dissolved solids (TDS) and individual ionic concentrations. This paper attempts to evaluate several models and highlights two major problems associated with them from analysis of water samples collected from two small catchments in East Devon and North Warwickshire. First, the presence of dissolved organic material, at the levels encountered in soil solutions, may seriously affect the SC/TDS relationship and will often be an undetected component of dissolved load. Secondly, the low pH of some water samples is shown to affect those models which calculate SC on the basis of individual ionic concentrations. This results from high H+ ion levels and associated increased solubility of other ions, such as Fe3+, Al3+ and Mn2+ which are not normally determined in water quality studies.

GANGLIOSIDE1−COMPOSITION OF BRAIN IN TAY‐SACHS DISEASE: INCREASED AMOUNTS OF GD2 AND N‐ACETYL‐β‐D‐GALACTOSAMINYL GD1a GANGLIOSIDE

Abstract— The ganglioside composition of the brain of a patient with Tay‐Sachs disease (TS‐brain) was determined by a newly developed ganglioside‐mapping procedure and compared with that of an age‐matched control brain. GM2 ganglioside was the predominant component in TS‐brain and the following gangliosides were also found, GM1, GD1a, GD1b and GT1 (major gangliosides in normal brain), and GM3, GD3, GD2 and GD1a‐GAN (minor or undetectable components of normal brain). Individual gangliosides were isolated by column chromatography using a combination of DEAE‐Sepharose, Iatrobeads and Silica Gel 60 and their structures were confirmed by comparing them with authentic standards using TLC, analysing their carbohydrate compositions by gas‐liquid chromatography and cleaving them sequentially with glycosidases. The amounts of individual components were measured by quantitative densitometric scanning of the thin‐layer plates. As a reflection of myelin breakdown, no sialosylgalactosyl ceramide was detectable in TS‐brain. Although the total amounts of all gangliosides except GM2 in TS‐brain were low, there were normal molar ratios of the main gangliosides in normal brain, that is, GM1, GD1a, GD1b and GT1. In comparison with the amount of GDla ganglioside, the amounts of GM2, GD2 and GD1a‐GAN, which contain N‐acetylgalactosamine as a terminal carbohydrate residue, were all elevated in TS‐brain. The long chain bases of individual gangliosides contained both C‐18 and C‐20 sphingosine in different ratios and the ratio of C‐20 to C‐18 increased in the gangliosides in the order: GM2 &lt; GM1 &lt; GD1a &lt; GD1a‐GAN &lt; GD1b &lt; GT1 in both normal brain and TS‐brain. In contrast, GD2 and GD3 gangliosides consisted mainly of C‐18 sphingosine. The C‐20 to C‐18 ratios of individual gangliosides in the TS‐brain were lower than those of age‐matched control brain.Hexosaminidase from Turbo cornutus showed the same specific activity and Km value in catalysing the cleavage of terminal N‐acetylgalactosaminyl residues from GM2, GD2 and GD1a‐GAN, suggesting that the brain gangliosides that increase in Tay‐Sachs disease may be cleaved by the same enzyme.

Improvement in the resolution of human sperm protamines by use of iodoacetamide as alkylating agent

By use of the neutral alkylating agent iodo [ 14C 1] acetamide instead of ethylene imine or iodoacetate, the resolution of human protamines on gel electrophoresis and ion-exchange chromatography has been improved. Using 20-cm gels, human protamines may be fractionated into seven bands, including the two chromatographically distinct forms of HP1 and a hitherto undetected component HP4. On ion-exchange chromatography, HP2 and the two forms of HP1 may be isolated in sufficient purity for sequence analysis.

Oxido-reductive titrations of cytochrome c oxidase followed by EPR spectroscopy

Experiments are described on oxido-reductive titrations of cytochrome c oxidase as followed by low-temperature EPR and reflectance spectroscopy. The reductants were cytochrome c or NADH and the oxidant ferricyanide. Experiments were conducted in the presence and absence of either cytochrome c or carbon monoxide, or both. An attempt is made to provide a complete quantitative balance of the changes observed in the major EPR signals. During reduction, the maximal quantity of heme represented in the high-spin ferric heme signals ( g ∼ 6; 2) is 25% of the total heme present, and during reoxidation 30%. With NADH reduction there is little difference between the pattern of disappearance of the low-spin ferric heme signals in the absence or presence of cytochrome c. The copper and high-spin heme signals, however, disappear at higher titrant concentrations in the presence of cytochrome c than in its absence. In these titrations, as well as in those with ferrocytochrome c, the quantitative balance indicates that, in addition to EPR-detectable components, EPR-undetectable components are also reduced, increasingly so at higher titrant concentrations. The quantity of EPR-undetectable components reduced appears to be inversely related to pH. A similar inverse relationship exists between pH and appearance of high-spin signals during the titration. At pH 9.3 the quantity of heme represented in the high-spin signals is < 5%, whereas it approximately doubles from pH 7.4 to pH 6.1. In the presence of CO less of the low-spin heme and copper signals disappears for the same quantity of titrant consumed, again implying reduction of EPR undetectable components. At least one of these components is represented in a broad absorption band centered at 655 nm. The stoichiometry observed on reoxidation, particularly in the presence of CO, is not compatible with the notion that the copper signal represents 100% of the active copper of the enzyme as a pair of interacting copper atoms.

Familial colon carcinoma in nail-patella syndrome.

FAMILIAL COLON CARCINOMA IN NAIL-PATELLA SYNDROMELOUIS A. GILULA and OWEN S. KANTORAudio Available | Share

Lymphocyte reactivity to serologically undetected components of the major histocompatibility complex.

THE major histocompatibility (H) systems are classically defined by antisera obtained following isoimmunization. The ability of the major histocompatibility loci antigens to stimulate bone marrow derived (B) lymphocytes to produce antibody is in fact so well accepted that some authors have suggested that virtually any antisera produced against allogeneic lymphocytes will react with major loci antigens. These serologically detected (SD) antigens in the mouse are controlled by two genetic loci (H-2K on the left and H-2D on the right) approximately 0.5 recombinational units apart1. The chromosomal segment between these two loci can be divided into two regions: one, next to H-2K, containing the presently identified loci controlling immune responsiveness (Ir)2,3 and two, between Ir and H-2D, a region including the Ss-Slp locus4. We will refer to this entire chromosomal region as the major histocompatibility complex (MHC). In addition to the H loci in the MHC there are many minor H loci segregating independently of the MHC which can, if different in two animals, lead to graft rejection. These differences are in many cases impossible to detect serologically. Until recently, however, H differences in the MHC were, as discussed above, thought to be easily recognizable by serological techniques.

Decametric Radio Emission from Jupiter

Observations of the decametric radio emission from Jupiter establish the existence of a hitherto undetected sub-millisecond component. Bursts of between 0.2 and 10 msec are not due to interplanetary scintillation but come from the planet itself.