Information-sharing between healthcare professionals, parents and children with cancer: more than a matter of information exchange.

This study examined participants' views on children's participation in information-sharing and communication interactions. A descriptive qualitative approach was taken with individual interviews held with children (The term 'children' is used to denote both children and adolescents and to avoid cumbersome repetition.) aged 7-16 years (n = 20), their parents (n = 22) and healthcare professionals (n = 40) at a children's hospital in Ireland. Data were analysed using the constant comparative method and managed with NVivo (version 8). The findings indicate that professionals strongly supported an open and honest approach to information-sharing; however, this viewpoint was not shared by all parents. The need to maintain hope and spirit and promote an optimistic identity influenced the amount and type of information shared by parents. Children trusted their parents to share information, and valued their parents' role as interpreters of information, advocates, and communication buffers. Most professionals endorsed parents' primacy as managers of information but experienced difficulty navigating a restricted stance. This study adds important insights into the complexities of information-sharing in triadic encounters. Professionals need to maintain an open mind about information-sharing strategies families may choose, remain sensitive to parents and children's information requirements and adopt a flexible approach to information provision.

Rational protein engineering and industrial application: structure prediction by homology and rational design of protein-variants with improved 'washing performance'--the alkaline protease from Bacillus alcalophilus.

The successful attempt is presented to engineer an enzyme with respect to its technical application by the use of computer-aided protein design techniques. Based on a modeled 3-D structure a number of mutants of a subtilisin-like protease was designed with the aim to increase its washing performance. The model of the highly alkaline subtilisin protease OPTICLEAN from Bacillus alcalophilus was developed by the process of 'modeling by homology' starting with the structure of subtilisin Carlsberg 1CSE.BRK from the Brookhaven protein databank. Amino acid changes and deletions were performed with the graphic protein design program BRAGI. Force field calculations and molecular dynamic simulations were made with AMBER 3.0. The comparison of the model and the later solved X-ray structure of OPTICLEAN shows a high similarity between the two structures. On the other hand, interesting deviations between the two structures were observed in some external loop regions. The comparison shows that the deviations are due to difficulties in the prediction of correct main chain torsion angles of additional prolines and the selection of correct loops in deletion or insertion regions.

Demonstration of Both a Photosynthetic and a Nonphotosynthetic CO(2) Requirement for NH(4) Assimilation in the Green Alga Selenastrum minutum.

Nitrogen-limited and nitrogen-sufficient cell cultures of Selenastrum minutum (Naeg.) Collins (Chlorophyta) were used to investigate the dependence of NH(4) (+) assimilation on exogenous CO(2). N-sufficient cells were only able to assimilate NH(4) (+) maximally in the presence of CO(2) and light. Inhibition of photosynthesis with 3-(3,4-dichlorophenyl)-1,1-dimethylurea, diuron also inhibited NH(4) (+) assimilation. These results indicate that NH(4) (+) assimilation by N-sufficient cells exhibited a strict requirement for photosynthetic CO(2) fixation. N-limited cells assimilated NH(4) (+) both in the dark and in the light in the presence of 3-(3,4-dichlorophenyl)-1,1-dimethylurea, diuron, indicating that photosynthetic CO(2) fixation was not required for NH(4) (+) assimilation. Using CO(2) removal techniques reported previously in the literature, we were unable to demonstrate CO(2)-dependent NH(4) (+) assimilation in N-limited cells. However, employing more stringent CO(2) removal techniques we were able to show a CO(2) dependence of NH(4) (+) assimilation in both the light and dark, which was independent of photosynthesis. The results indicate two independent CO(2) requirements for NH(4) (+) assimilation. The first is as a substrate for photosynthetic CO(2) fixation, whereas the second is a nonphoto-synthetic requirement, presumably as a substrate for the anaplerotic reaction catalyzed by phosphoenolpyruvate carboxylase.

Characterization of the sacQ genes from Bacillus licheniformis and Bacillus subtilis.

The sacQ gene from Bacillus licheniformis was cloned and expressed in Bacillus subtilis. Deletion analysis shows that it encodes a 46-amino-acid polypeptide homologous to the B. subtilis sacQ gene product. The polypeptide, when it is overexpressed, activates the expression of a number of target genes in B. subtilis, all encoding secreted enzymes: alkaline protease, levansucrase, beta-glucanase(s), xylanase, and alpha-amylase. The maximum stimulations measured for alkaline protease and levansucrase were by a factor of 70 and 50, respectively, when the sacQ gene from B. licheniformis was present on a multicopy plasmid in B. subtilis. The sacQ genes from B. subtilis and B. licheniformis, cloned in the same multicopy plasmid, were compared under the same conditions. The sacQ gene from B. licheniformis was more efficient than the sacQ gene from B. subtilis in producing the hypersecretion phenotype. The sacQ structural genes from B. subtilis and B. licheniformis were placed under the control of the same inducible promoter. Hypersecretion was specifically obtained under conditions of full induction of the promoter. The target site of levansucrase regulation by sacQ was identified as a 440-base-pair fragment located in the 5' noncoding region of sacB, suggesting transcriptional control.

A method to determine tannin concentration by the measurement and quantification of protein - tannin interactions.

Protein determinations on protein-tannin complexes after protein isolation (gel filtration and trichloroacetic acid [TCA] precipitation) or phenolic extraction (polyvinyl pyrrolidone [PVP] and organic solvent precipitation) were unsuccessuful. Kjeldahl determinations of the amount of unprecipitated protein bovine serum albumin [BSA] showed a sigmoid relationship with increasing concentrations of tannins. A similar relationship was found for the reduced viscosity of BSA and plant protein, and the concentration of tannin. Non-linear regression and curve normalization allowed three variable (k 1, k 2 and T 1/2) to be defined for the quantification of the protein-tannin interaction/s. Such a treatment may be useful in studies of the role of tannins in plant-herbivore interactions.

Phosphorylated intermediate of a transport ATPase and activity of protein kinase in membranes from corn roots.

A maize-root microsomal fraction was enriched in ATPase by treatment with Triton X-100. This activity, which reached 1.2-2.0/mumol Pi x min-1 x mg protein-1, was specific for ATP, very slightly stimulated by K+, inhibited by orthovanadate and diethylstilbestrol, resistant to oligomycin and azide, and had a Km of 1.2 mM MgATP. Incubation of the microsomal fraction with [gamma 32-P]ATP followed by electrophoresis in acid conditions revealed the presence of several phosphoproteins. The phosphorylation of a 110000-Mr polypeptide reached the steady-state level in less than 5 s and rapidly turned over the phosphate group. The phosphorylation level was an hyperbolic function of the [ATP] with a Km of 0.6 mM, suggesting that the rate of Pi production was proportional to the phosphoprotein concentration. The extent of phosphoprotein was decreased by vanadate and diethylstilbestrol. The phosphorylation level was 30% decreased by 50 mM K+ or Na+ while the ATPase activity was slightly stimulated (12% and 5%, respectively). The polypeptide could not be phosphorylated in reverse by Pi. This phosphorylated intermediate from maize-root microsomes exhibits molecular properties characteristic of transport ATPases such as the yeast plasma membrane H+-translocating ATPase. This similarity indicates existence of a transport ATPase in plant plasma membranes. Three other plant microsomal polypeptides (Mr = 52000, 17000 and 16000) and a low molecular weight component (Mr less than 1000) were phosphorylated much more slowly, were not undergoing a rapid turnover and were not hydrolysed by hydroxylamine. These phosphoproteins and the Mr less than 1000 phosphorylated component were inhibited by vanadate and diethylstilbestrol. These properties are similar to those of the protein kinase activity recently described in yeast plasma membranes.

Exchange of oxygen between phosphate and water catalyzed by the plasma membrane ATPase from the yeast Schizosaccharomyces pombe.

The ATPase of the plasma membrane isolated from the yeast Schizosaccharomyces pombe catalyses a medium Pi in equilibrium H2O exchange in the presence of Mg2+ and in the absence of ATP and ADP. (formula, see text) The Pi in the E.Pi species tumbles in the active site so that each of its oxygens has an equal probability of exchange with water. The partition coefficient (Pc = k2/k2 + k-1) is 0.45. The total rate of oxygen exchange, Vex, representing the rate of incorporation of water oxygens occurring during hydrolysis of E--P into E.Pi (Vex = k-2[E--P]) is dependent on the [Pi] with an apparent Km of 177 mM, reflecting the very low affinity of the enzyme for Pi. The maximal exchange rate is 6.7 micrograms atoms of oxygen X min-1 X mg-1 of protein. The individual kinetic constants are evaluated: k2 = 3.4 X 10(3) min-1, k-2 = 5.50 X 10(5) min-1 and k-1 = 4.11 X 10(3) min-1. Under conditions of uncoupled transport, the hydrolysis of E--P is exergonic as [E.Pi]/[E--P] = k-2/k2 = 164. During hydrolysis of ATP, the rate of medium Pi in equilibrium H2O exchange activity as well as the extent of phosphorylation of the enzyme from Pi are markedly stimulated: 7.9 and 5.3 times, respectively, whereas the Pc is not modified. These data are most simply interpretated by the existence of two isomeric forms of the enzyme; one is specific for binding ATP and the other for binding Pi. The Pc for intermediate Pi in equilibrium H2O exchange, when the E--P species is formed from cleavage of [gamma-18O]ATP, is the same as for medium exchange, indicating that the same exchange pathway operates under both conditions. Varying the [ATP] had very little effect on the Pc, indicating little or no cooperativity between different catalytic sites under the conditions used in this study.

Large-scale purification and phosphorylation of a detergent-treated adenosine triphosphatase complex from plasma membrane of Saccharomyces cerevisiae.

A new procedure for large-scale preparation of plasma-membrane-bound ATPase from Saccharomyces cerevisiae is described. The crude membrane fraction is purified by selective extraction with three successive detergents: deoxycholate (0.25 mg/mg protein), Triton X-100 (0.25%) and lysophosphatidylcholine (1 mg/mg protein). These treatments extract the mitochondria and strip the plasma membrane. From 1 kg commercial baker's yeast, 200 mg of plasma membrane proteins are isolated in 2--3 days. Plasma-membrane-bound ATPase of specific activity of 10--13 mumol Pi x min-1 x mg protein-1 is obtained with a yield estimated to 60%. Dodecylsulfate/polyacrylamide gel electrophoresis shows three predominant polypeptides of Mr = 95000, 70000 and 56000 in the purified membrane fraction. The major polypeptide of Mr = 95000 identified as the ATPase subunit is phosphorylated by millimolar concentrations of ATP. The phosphorylated intermediate reaches the steady-state level in less than 100 ms and turns over very rapidly. It is hydrolyzed by hydroxylamine. Its formation is prevented by the ATPase inhibitors vanadate and Dio-9, a plasma-membrane ATPase inhibitor of unknown structure. At least four other membrane proteins are phosphorylated with much slower kinetics, presumably through the action of protein-kinase(s).

The purified plasma membrane ATPase of the yeast Schizosaccharomyces pombe forms a phosphorylated intermediate.

An acid slab gel electrophoresis method of high-resolving power allows detection of a phosphorylated form in the purified ATPase of the yeast Schizosaccharomyces pombe and identification of this catalytic intermediate among the different phosphopeptides of a plasma membrane preparation. At a maximum steady state rate of MgATP hydrolysis by the membrane-bound ATPase, 20 to 40% of the ATPase subunits of 100,000 daltons are in a phosphorylated form, while only 0.8% of the subunits of the purified ATPase are phosphorylated under the same conditions. The phosphorylated intermediate reaches the steady state level in less than 2 s and rapidly turns over. The phosphorylated substance is cleaved by hydroxylamine and is relatively stable in acids but is readily hydrolyzed in alkaline or in acid alcoholic media. These results suggest that the intermediate is an acylphosphate. The phosphorylation reaction has an apparent Km value of 3.0 mM MgATP for the plasma membrane-bound ATPase and 0.6 mM MgATP for the purified ATPase. Plasma membranes contain several other minor phosphorylated components whose kinetic behavior is typical of phosphorylation by protein kinase. Artifactual production of two forms of the ATPase by phenylmethanesulfonyl fluoride-sensitive proteases liberated during cell disruption is also demonstrated.