Multifaceted Modelling of Complex Business Enterprises

We formalise and present a new generic multifaceted complex system approach for modelling complex business enterprises. Our method has a strong focus on integrating the various data types available in an enterprise which represent the diverse perspectives of various stakeholders. We explain the challenges faced and define a novel approach to converting diverse data types into usable Bayesian probability forms. The data types that can be integrated include historic data, survey data, and management planning data, expert knowledge and incomplete data. The structural complexities of the complex system modelling process, based on various decision contexts, are also explained along with a solution. This new application of complex system models as a management tool for decision making is demonstrated using a railway transport case study. The case study demonstrates how the new approach can be utilised to develop a customised decision support model for a specific enterprise. Various decision scenarios are also provided to illustrate the versatility of the decision model at different phases of enterprise operations such as planning and control.     

The extracellular and cytoplasmic proteomes of the non-virulent Bacillus anthracis strain UM23C1-2

The recently published genome sequence of Bacillus anthracis Ames has facilitated the prediction of proteins associated with the virulence of this bacterium. The aim of this study was to define reference maps for the extracellular and cytoplasmic proteomes of the avirulent B. anthracis strain UM23C1-2 that are useful for physiological studies and the development of improved vaccines. Using 2-DE and subsequent MALDI-TOF-TOF MS, 64 proteins were identified in the extracellular proteome, only 29 of which were predicted to be exported into the culture medium. The latter included chitinases, proteases, nucleotidases, sulfatases, phosphatases and proteins of unknown function. Of the remaining proteins in the culture medium, 18 were predicted to be associated with the cell wall or anchored on the trans side of the cytoplasmic membrane while 17 other proteins lacked identifiable export signals and were predicted to be cytoplasmic proteins. Among the S-layer proteins, Sap and Eag account for 10% of the total extracellular proteome. Many of the proteins are predicted to contribute to the virulence and antigenic signature of B. anthracis. We have also studied the composition of the cytoplasmic proteome, identifying 300 distinct proteins. The most abundant cytoplasmic proteins are primarily those involved in glycolysis, amino acid metabolism, protein translation, protein folding and stress adaptation. The presence of a variety of proteases, peptidases, peptide binding proteins, as well as enzymes required for the metabolism of amino acids, suggests that B. anthracis is adapted to life in a protein-rich environment rather than the soil. We therefore speculate that proteases and peptidases could be useful targets for the development of improved vaccines. In addition, both of these B. anthracis compartment-specific proteomes can be used as reference maps to monitor changes in the production of secreted and cytosolic proteins that occur, for example, during growth in macrophages.     

Regulation of the black bullhead hepatic beta-adrenoceptors

Black bullhead catfish (Ameiurus melas) were exposed to air for 1 h to examine the effect of an acute stress on the distribution and function of the hepatic beta-adrenoceptors (beta-ARs). Air exposure significantly reduced both adrenaline (ADR)- and noradrenaline (NADR)-stimulated glucose production in isolated hepatocytes with no effect on either receptor affinity (K(d)) or number of binding sites (B(max)). A 24 h exposure of isolated hepatocytes to the beta-agonist isoproterenol also had no significant impact on either binding parameter. Competition studies using selective agonists and antagonists suggest that the hepatic beta-AR in this species is pharmacologically beta(2)-like. However in addition to the beta(2)-AR, molecular evidence provides support for the existence of hepatic beta-ARs that phylogenetically group with the beta(3)-ARs and the beta(1)-ARs. Despite the presence of several potential phosphorylation sites in the third intracellular loop and cytoplasmic tail of the bullhead beta(2)-AR, no significant changes were observed in the binding parameters. While physiological data supports the presence of only a single subtype, molecular data supports the existence of multiple beta-AR subtypes in this species. The mechanisms thought to regulate mammalian beta-ARs exist in the bullhead ARs reported here but these mechanisms are not as effective in this fish system as in mammals.     

High-frequency intragenomic heterogeneity of the ribosomal DNA intergenic spacer region in Trichophyton violaceum

The intergenic spacer (IGS) of the rRNA genes was analyzed from the dermatophyte Trichophyton violaceum isolated from cases of tinea capitis in Taiwan and Iran. T. violaceum strains were cultured from different colonies, from single conidial colonies derived by dilution plating, and from micromanipulation of single conidia from clinical samples. A ribosomal DNA probe hybridizing to multiple EcoRI fragments was used to compare restriction fragment length polymorphisms in different T. violaceum isolates. The arthroconidia of T. violaceum that form in vivo during infection were shown to contain a single nucleus by 4',6'-diamidino-2-phenylindole staining. IGS regions from an isolate cultured from a single conidium were amplified, cloned, and sequenced. The results identified that heterogeneity exists between IGS regions within a single T. violaceum genome due to different copy numbers of a 171-bp tandem repeat. This suggests that the IGS of T. violaceum is partially excluded from the concerted evolution of the rRNA gene locus. The heterogeneous character of the IGS regions in T. violaceum contrasts with the closely related dermatophyte Trichophyton rubrum, posing further questions on the phylogeny and the evolution of dermatophyte fungi.     

Analysis of sister chromatid exchanges in lymphocytes cultured from 71 healthy men

Sister chromatid exchanges (SCE) were analyzed in peripheral blood lymphocytes from a select group of 71 healthy men, 56 nonsmokers and 15 cigarette smokers. In addition to estimating baseline SCE, data were examined to seek relationships of SCE frequencies to age and smoking. The baseline value of 7.53 SCE per cell from the 56 nonsmokers was within the range (5.60 to 9.10 SCE/cell) reported for other human populations. No relationship was found between the mean SCE frequency per cell and age. However, a significant increase in the SCE mean value was observed in smokers as compared to nonsmokers. The results of this study are compared with those of other reports on SCE effects of age and smoking.Abbreviations BUdR 5-bromo,2-deoxyuridine - SCE sister chromatid exchange     

The construction and in vitro testing of photo-activatable cancer targeting folated anti-CD3 conjugates

The construction and in vitro testing of a photo-activatable anti-tumour immuno-regulatory antibody is described. In this ‘cloaked’ folated anti-CD3 antibody conjugate, the folate portion of the conjugate is free to bind to folate receptor expressing cancer cells, whilst the anti-CD3 activity is effectively rendered inert by a coating of photo-labile 2-nitrobenzyl groups. On irradiation with UV-A light the activity of the anti-CD3 antibody is restored, not only when it is required, but more importantly, only where it is required. The conjugate can then attract killer T-cells to the surface of the tumour cells and kill them. Unirradiated normal tissues, to which the conjugate has been targeted by specific and non-specific binding, remain unharmed. We believe that these ‘photo-switchable’ conjugates could be used to markedly improve the targeting of the immune response to folate receptor (FR) expressing ovarian and breast cancers whilst minimising the side effects in the rest of the body.     

The heme precursor delta-aminolevulinate blocks peripheral myelin formation

Delta-aminolevulinic acid (δ-ALA) is a heme precursor implicated in neurological complications associated with porphyria and tyrosinemia type I. Delta-ALA is also elevated in the urine of animals and patients treated with the investigational drug dichloroacetate (DCA). We postulated that δ-ALA may be responsible, in part, for the peripheral neuropathy observed in subjects receiving DCA. To test this hypothesis, myelinating cocultures of Schwann cells and sensory neurons were exposed to δ-ALA (0.1–1 mM) and analyzed for the expression of neural proteins and lipids and markers of oxidative stress. Exposure of myelinating samples to δ-ALA is associated with a pronounced reduction in the levels of myelin-associated lipids and proteins, including myelin protein zero and peripheral myelin protein 22. We also observed an increase in protein carbonylation and the formation of hydroxynonenal and malondialdehyde after treatment with δ-ALA. Studies of isolated Schwann cells and neurons indicate that glial cells are more vulnerable to this pro-oxidant than neurons, based on a selective decrease in the expression of mitochondrial respiratory chain proteins in glial, but not in neuronal, cells. These results suggest that the neuropathic effects of δ-ALA are attributable, at least in part, to its pro-oxidant properties which damage myelinating Schwann cells.     

Extensive fusion of haematopoietic cells with Purkinje neurons in response to chronic inflammation

Transplanted bone marrow-derived cells (BMDCs) have been reported to fuse with cells of diverse tissues, but the extremely low frequency of fusion has led to the view that such events are biologically insignificant. Nonetheless, in mice with a lethal recessive liver disease (tyrosinaemia), transplantation of wild-type BMDCs restored liver function by cell fusion and prevented death, indicating that cell fusion can have beneficial effects. Here we report that chronic inflammation resulting from severe dermatitis or autoimmune encephalitis leads to robust fusion of BMDCs with Purkinje neurons and formation of hundreds of binucleate heterokaryons per cerebellum, a 10-100-fold higher frequency than previously reported. Single haematopoietic stem-cell transplants showed that the fusogenic cell is from the haematopoietic lineage and parabiosis experiments revealed that fusion can occur without irradiation. Transplantation of rat bone marrow into mice led to activation of dormant rat Purkinje neuron-specific genes in BMDC nuclei after fusion with mouse Purkinje neurons, consistent with nuclear reprogramming. The precise neurological role of these heterokaryons awaits elucidation, but their frequency in brain after inflammation is clearly much higher than previously appreciated.     

Hexokinase isoenzymes in tissues of the adult and developing guinea pig

Changes in the activities and isoenzyme distribution of hexokinase were determined in a number of tissues during the development of the guinea pig. The total activity in the fetal liver showed a large fall during the second half of gestation to reach adult values by term. With normal diet the fetal, neonatal, and adult livers had isoenzymes I and III but little or no detectable IV (glucokinase). The fetal liver had predominantly type I, but the proportion of type III increased during development. The kinetics of the guinea pig isoenzymes were similar to those reported for the rat. Two additional isoenzymes with mobility between I and II were detected in the fetal liver and blood. They appear to have kinetic properties similar to type I. Detectable liver glucokinase activity was induced by glucose administration to adult guinea pigs. The total activity in kidney, brain and skeletal muscle showed a postnatal rise while in the fetal heart it was high and declined after birth. These tissues contained predominantly type I with varying proportions of type III hexokinase. The ratio of particulate-bound to soluble hexokinase varied from tissue to tissue. All except the liver showed a significant increase in binding after birth. The changes are discussed in relation to the control of glucose utilization in the fetal and neonatal periods.