Base excision repair of cyclobutane pyrimidine dimers

Several times within the teleost fish order Tetraodontiformes singular jaw adducting muscles have been effectively 'duplicated' by physical subdivision to produce new muscles. This morphological system provides an opportunity to investigate how the functional complexity of muscular systems changes with evolutionary increases in the number of component muscles. In this study we asked if muscle duplication has lead to functional diversification by comparing the motor patterns of muscles that result from subdivision events. The activity patterns of five different sets of duplicated muscles were quantified with electromyographic recordings (EMG) from four individuals in each of three species during processing of three prey types. Prey varied in durability and elusiveness (live fiddler crabs, pieces of squid tentacle and live paeneid shrimps). For each cycle of prey processing, measurements were made of the relative onset time of each adductor muscle, the duration of each burst of activity, and the relative intensity of each activity burst. Two types of functional divergence of muscles were observed in analyses of variance conducted on the EMG variables. In two of the 15 variables examined, the timing of activity of the descendant set of muscles differed. In another three of the 15 variables, there were significant interactions between muscle and prey type, indicating a prey effect which differed in the descendant muscles. Overall, evidence of motor divergence was found in three of five cases of muscle duplication. This indicates that muscle subdivision has led to increased functional complexity of the jaw-adductor muscle system in tetraodontiform fishes.     

FLOW CYTOMETRIC MONITORING OF RHODAMINE 123 AND A CYANINE DYE UPTAKE BY YEAST DURING CIDER FERMENTATION

Flow cytometry of rhodamine 123- or cyanine-stained cider yeast shows that the capacity for mitochondrial uptake of these cationic dyes is lost early in the fermentation. Survival of prolonged anaerobiosis (for at least 22 days) at high ethanol concentrations (at least 11% v/v) during cider fermentation does not require the maintenance of a measurable inner mitochondrial transmembrane electrochemical potential. Confocal laser scanning microscopy of yeasts after exposure to either of the cationic dyes confirms the lack of mitochondrial development and inability of the fermentative organisms to take up the fluorophores. Aeration of samples taken from the fermentation vessels restores the ultrastructure and the dye uptake capacity of the yeasts. This indicates that the changes are reversible, and that the organisms have retained their viability.     

The Optimization of an Epifluorescence Microscopy Technique for the Direct Counting of Clumped Bacteria

The enumeration of heterotrophic bacteria is an important measure of water quality in mains'distribution systems. Conventional methods of enumerating bacteria by plate counts do not distinguish between single bacteria and clumps of cells; however, various methods have been reported which use epifluorescence microscopy to give a direct count of bacteria. There appears to be no standard method for the preparation of samples, with the choice of fluorochrome and staining technique varying considerably – even between workers using similar environmental samples. A number of the reported methods were tested, and a technique was developed which enabled a consistent total count of bacterial cells (occurring both singularly and in clumps) to be obtained.     

Function of protonatable residues in the flagellar motor of Escherichia coli: a critical role for Asp 32 of MotB

Rotation of the bacterial flagellar motor is powered by a transmembrane gradient of protons or, in some species, sodium ions. The molecular mechanism of coupling between ion flow and motor rotation is not understood. The proteins most closely involved in motor rotation are MotA, MotB, and FliG. MotA and MotB are transmembrane proteins that function in transmembrane proton conduction and that are believed to form the stator. FliG is a soluble protein located on the cytoplasmic face of the rotor. Two other proteins, FliM and FliN, are known to bind to FliG and have also been suggested to be involved to some extent in torque generation. Proton (or sodium)-binding sites in the motor are likely to be important to its function and might be formed from the side chains of acidic residues. To investigate the role of acidic residues in the function of the flagellar motor, we mutated each of the conserved acidic residues in the five proteins that have been suggested to be involved in torque generation and measured the effects on motility. None of the conserved acidic residues of MotA, FliG, FliM, or FliN proved essential for torque generation. An acidic residue at position 32 of MotB did prove essential. Of 15 different substitutions studied at this position, only the conservative-replacement D32E mutant retained any function. Previous studies, together with additional data presented here, indicate that the proteins involved in motor rotation do not contain any conserved basic residues that are critical for motor rotation per se. We propose that Asp 32 of MotB functions as a proton-binding site in the bacterial flagellar motor and that no other conserved, protonatable residues function in this capacity.     

Delay of wetting propagation during jet impingement quenching for a high temperature surface

Transient heat transfer has been investigated experimentally with a subcooled water jet during quenching of hot cylindrical blocks made of copper, brass and steel for initial surface temperatures from 250 to 400 °C. The jet velocity was from 3 to 15 m/s and jet subcooling from 5 to 80 K with a jet diameter of 2 mm. When the jet strikes the hot surface, the wetting front becomes stagnant for a certain period of time in a small central region before wetting the entire surface. This wetting delay may be described as the resident time which is a strong function of block material and jet subcooling and also a function of initial block temperature and jet velocity. New correlations for the resident time and the surface temperature at the resident time at the wetting front have been proposed.     

Eosinophil recruitment to the lung in a murine model of allergic inflammation. The role of T cells, chemokines, and adhesion receptors

Eosinophil accumulation is a distinctive feature of lung allergic inflammation. Here, we have used a mouse model of OVA (ovalbumin)-induced pulmonary eosinophilia to study the cellular and molecular mechanisms for this selective recruitment of eosinophils to the airways. In this model there was an early accumulation of infiltrating monocytes/macrophages in the lung during the OVA treatment, whereas the increase in infiltrating T-lymphocytes paralleled the accumulation of eosinophils. The kinetics of accumulation of these three leukocyte subtypes correlated with the levels of mRNA expression of the chemokines monocyte chemotactic peptide-1/JE, eotaxin, and RANTES (regulated upon activation in normal T cells expressed and secreted), suggesting their involvement in the recruitment of these leukocytes. Furthermore, blockade of eotaxin with specific antibodies in vivo reduced the accumulation of eosinophils in the lung in response to OVA by half. Mature CD4+ T-lymphocytes were absolutely required for OVA-induced eosinophil accumulation since lung eosinophilia was prevented in CD4+-deficient mice. However, these cells were neither the main producers of the major eosinophilic chemokines eotaxin, RANTES, or MIP-1alpha, nor did they regulate the expression of these chemokines. Rather, the presence of CD4+ T cells was necessary for enhancement of VCAM-1 (vascular cell adhesion molecule-1) expression in the lung during allergic inflammation induced by the OVA treatment. In support of this, mice genetically deficient for VCAM-1 and intercellular adhesion molecule-1 failed to develop pulmonary eosinophilia. Selective eosinophilic recruitment during lung allergic inflammation results from a sequential accumulation of certain leukocyte types, particularly T cells, and relies on the presence of both eosinophilic chemoattractants and adhesion receptors.     

The conundrum of IT management

This paper presents a robust argument as to why it can be difficult for chief information officers (CIOs) to generate business value from investments that their organizations make in information technology (IT) with contemporary organizational structures, authority patterns, processes and mindsets. This argument is built on the subtle premise that organizations should not seek to merely manage IT but to manage the delivery of business value through IT. It takes the view that this latter quest is knowledge-based and that the knowledge resources to successfully deliver this value are distributed throughout the organization. Crucially, this knowledge is not located solely within the IT function, presenting a challenge for the CIO for its integration and coordination. With the CIO having little or no jurisdiction over all required knowledge, its deployment will therefore be fragmented. The conundrum of IT management is how to generate value through IT without having access and authority over necessary resources. Research and practitioner implications of this analysis are highlighted.