The heterogeneity of bovine growth hormone. Extraction from the pituitary of components with different biological and immunological properties.

Evidence is available to suggest that Ca2+-calmodulin and cyclic nucleotides are involved in the regulation of ion transport in rabbit ileum. Since both Ca2+-calmodulin and cyclic nucleotides exert many of their effects by phosphorylation, the effects of Ca2+-calmodulin and cyclic nucleotides on phosphorylation of purified microvillus membrane from rabbit ileal mucosa were evaluated. Ca2+-calmodulin increased phosphorylation of five microvillus-membrane peptides, with Mr values of 137000, 77000, 58000, 53000 and 50000. The increases in phosphorylation caused by Ca2+-calmodulin were: Mr-137000 peptide, 111 +/- 26%; Mr-77000 peptide, 71 +/- 17%; Mr-58000 peptide, 51 +/- 8%; Mr-53000 peptide, 113 +/- 20%. These increases were maximal at 1 microM-calmodulin and 0.3-0.9 microM free Ca2+; concentrations of Ca2+ causing half-maximal effects on phosphorylation for the different peptides were 0.06-0.12 microM. Cyclic AMP and cyclic GMP increased phosphorylation of two peptides, of Mr 137000 and 85000. The concentrations of cyclic nucleotides giving half-maximal phosphorylation of the Mr-137000 peptide were 0.3 microM-cyclic AMP and 4.6 microM-cyclic GMP, and for the Mr-85000 peptide, 3.9 microM-cyclic AMP and 0.05 microM-cyclic GMP. The maximal increase in phosphorylation of the Mr-137000 peptide was 200% for cyclic AMP and 95% for cyclic GMP, and that of the Mr-85000 peptide was 220% for cyclic AMP and 120% for cyclic GMP. These studies demonstrate the existence of Ca2+-calmodulin-, cyclic AMP- and cyclic GMP-dependent protein kinases and substrate proteins in purified rabbit ileal microvillus membranes and that Ca2+ can regulate phosphorylation of these proteins over the presumed physiological concentration range of cytosol free Ca2+.     

Development and characterisation of a line of bread wheat,Triticum aestivum,which lacks the short-arm satellite of chromosome 1B and the Gli-B1 locus

Summary About 360 offspring of a tri-parental cross were screened by gel electrophoresis and unexpectedly one of them did not contain chromosome 1B -gliadins derived from either of the primary parents. A line disomic for the -gliadin null was developed from the surviving embryo half of the unique grain. Two dimensional electrophoresis revealed that all the storage protein genes at Gli-B1, coding for -gliadins, -gliadins and low-molecular-weight subunits of glutenin as well as the -gliadin, were not expressed. The nuclei of dividing root-tip cells were shown by light microscopy to lack the normal short-arm satellites of chromosome 1B, indicating that the genes for the missing storage proteins had been lost through a terminal deletion. Using a radioactive ribosomal RNA probe, the deficient 1B chromosomes were shown to contain ribosomal RNA genes demonstrating that at least two-thirds of the short arm was still present. Examination of serial sections of chromosome 1B at metaphase by low-power electron microscopy showed that the point of scission of this chromosome was within the secondary constriction where the ribosomal RNA genes are located. The Gli-B1 locus must therefore be carried on the short-arm satellite. Transmission of the deficient chromosome from female gametes to progeny was normal (i.e., about 50%) but from pollen it was poor (8.8%). Recombination mapping indicated that the distance from the ribosomal RNA genes (Nor1) to Glu-B1 was 22 cM, equivalent to 13 cM from Nor1 to the centromere.     

Correlation between serum ionised calcium and serum albumin concentrations in two hospital populations.

One quarter of 172 patients from two hospitals with no obvious disturbances of calcium homeostasis and with total serum calcium concentrations that were normal after adjustment for albumin concentration had low serum ionised calcium concentrations. The low values were not due to changes in pH but were associated with hypoalbuminaemia. Significant positive regressions of ionised calcium on albumin concentration were observed in patients from both hospitals and also in 48 healthy laboratory staff. Because the regressions did not differ between patients and healthy subjects the low ionised calcium values associated with hypoalbuminaemia are unlikely to have been of pathological importance. These findings indicate that interpreting serum ionised calcium concentrations in patients with a reduced serum albumin concentration on the basis of a reference range determined in subjects with a normal serum albumin concentration may be clinically misleading.     

NADP-isocitrate dehydrogenase polymorphism in the Atlantic salmon Salmo salar

Electrophoretic variation of Atlantic salmon NADP-isocitrate dehydrogenase in liver extracts of material from Ireland is interpreted in terms of two loci, IDH-A and IDH-B , coding for cytoplasmically-located isozymes. The IDH-A locus is polymorphic with qIDH-A ¹=0.18 and qIDH-A ²=0.82. This polymorphism is of potential value for investigating the population genetics of the two races of Atlantic salmon in Ireland. An additional, monomorphic band which appears in heart extracts may be a mitochondrial enzyme coded by a third locus.     

Production of tremorgenic toxins by Penicillium janthinellum Biourge: a possible aetiological factor in ryegrass staggers.

Topsoil, herbage and faeces collected during an outbreak of ryegrass staggers in sheep were examined for tremorgenic penicillia. No such fungi were recovered from the plant material, but they were found among the predominant fungi in the soil and faecal samples. The commonest species of Penicillium, and almost the only tremorgenic species encountered, was Penicillium janthinellum Biourge. When fed to sheep, the mycelium of this fungus evoked a number of the clinical signs seen in field cases of ryegrass staggers. Two tremorgenic toxins were isolated from the mycelial felts and available evidence indicates that they are verruculogen and fumitremorgin A. P. janthinellum also produced these tremorgens when cultured in moist, autoclaved soil, but not in unheated soil. The results obtained from this study are in accord with the hypothesis that ryegrass staggers is caused by tremorgenic mycotoxins.     

A Comparison of Purified Host Specific Toxin from Helminthosporium maydis, Race T, and Its Acetate Derivative on Oxidation by Mitochondria from Susceptible and Resistant Plants

NADH or succinate oxidation and malate oxidation were differentially affected in mitochondria from both susceptible and resistant corn by a purified and chemically characterized preparation of host-specific toxin from Bipolaris (Helminthosporium) maydis, race T. NADH and succinate oxidation by susceptible T corn mitochondria were stimulated 50 to 200% with apparent uncoupling from the cytochrome chain at approximately 10(-9)m toxin (5 to 20 ng/ml). Significant inhibition of malate oxidation was observed at slightly higher toxin concentrations, but oxidation was still coupled to ADP utilization. Inhibition of malate oxidation also was observed in N corn (resistant) and soybean mitochondria at approximately 1,000-fold greater concentrations, but stimulation of NADH and succinate oxidation was not found at any toxin concentration tested.A fully acetylated toxin derivative at approximately 1 microgram per milliliter also caused stimulation of NADH or succinate oxidation in T corn mitochondria, but not those of N corn or soybean mitochondria at 100 micrograms per milliliter. Malate oxidation was inhibited to the same extent by toxin acetate with mitochondria from T corn, N corn, and soybean. The blocking of hydroxyl groups in race T toxin by acetyl functions eliminated selectivity toward malate oxidation only. The data suggest that inhibition of malate oxidation is either a separate or secondary effect of selective action of toxin on T corn mitochondria, perhaps by interference with transport in or out of the matrix. Sensitivity of T, but not N, corn mitochondria to purified toxin decays within minutes after pellets are suspended in aqueous osmotica, with no obvious change in mitochondrial integrity. The action of race T toxin seems to involve a labile process, such as ion gradient(s), or an unstable structural conformation of T corn mitochondria.     

Cell free synthesis of some storage protein subunits by polyribosomes and RNA isolated from developing seeds of pea (Pisum sativum L.)

Polyribosomes which have template activity in the wheat germ system have been isolated from developing pea seeds. Some of the translation products have identical mobilities to the vicilin and legumin subunits by SDS-PAGE. Certain products were specifically immunoprecipitated with antisera prepared against purified vicilin and legumin fractions. Various RNA fractions including poly A-rich RNA have also been isolated from polyribosomes and shown to direct the synthesis of polyripeptides whose properties are similar to the storage protein subunits. The results are discussed in relationship to other investigations with seed storage protein biosynthesis in vitro.Abbreviations DTT dithiothreitol - SDS-PAGE SDS-polyacrylamide gel electrophoresis - TCA tricarboxylic acid     

Management of radiation necrosis and advanced cancer of the chest wall in patients with breast malignancy.

Aggressive resection, with individualized reconstruction by several methods, is of value in many patients with radiation necrosis and/or advanced breast cancer of the chest wall. Although this does not always significantly lengthen survival, it can improve the quality of life markedly in many instances. Remarkably large defects can be reconstructed with single-stage procedures.     

Effectiveness of out-of-hours biochemistry investigations.

A survey was carried out of doctors who used their out-of-hours biochemistry service to find out why requests for investigations were made, how often the results altered patient management, and whether they could define areas where investigations were unproductive. Of 107 questionnaires distributed, 147 (88%) were completed. In 86% the requests were for diagnosis or immediate patient management and in 35% the results actually altered management. Senior clinical staff were more efficient than their juniors in instigating biochemical investigations that proved to be effective. In no instance where the clinical staff predicted that it was unlikely that the results would alter management was management altered. It is suggested that joint reviews of case notes by junior and senior clinical staff would prove to be the most appropriate way to increase the effectiveness and efficiency of clinical investigation.