Expression of neuronal nitric oxide synthase (nNOS) and nitric-oxide-induced changes in cGMP in the urothelial layer of the guinea pig bladder

The urothelium plays a sensory role responding to deformation of the bladder wall; this involves the release of adenosine trisphosphate (ATP) and nitric oxide (NO), which affect afferent nerve discharge and bladder sensation. The urothelial cells responsible for producing ATP and NO and the cellular targets, other than afferent nerves, for ATP and NO remain largely unexplored. Sub-urothelial interstitial cells (SU-ICs) lie immediately below the urothelium and respond to NO with a rise in cGMP. To determine which cells might target SU-ICs by producing NO, areas of dome, lateral wall and base wall were treated with isobutyl-methyl-xanthine, exposed to the NO donor diethylamino NONOate and then fixed for immunohistochemistry. Surface urothelial cells (SUCs) in the base and dome expressed neuronal nitric oxide synthase (nNOS), whereas those in the lateral wall did not. Distinct populations of SUCs were present in the bladder base. SUCs with significant amounts of nNOS lay adjacent to cells with low levels of nNOS. In specific base regions, the few SUCs present contained nNOS within discrete intracellular particles. In the basal urothelial cell (BUC) layer of the lateral wall, nNOS-positive (NOS⁺) BUCs neither showed an elevation in cGMP in response to NO, nor expressed the 1 sub-unit of soluble guanylate cyclase, protein kinase I or protein kinase II. Thus, they produced but did not respond to NO. The BUC layer also stained for the stem cell factor c-Kit suggesting its involvement in urothelial cell development. No NOS⁺ BUCs were present in the SUC-sparse region in the bladder base. Exogenous NO produced an elevation in cGMP in SUCs and SU-ICs. The distribution and proportion of these target cells varied between the dome, lateral wall and base. cGMP⁺ SU-ICs were present as a dense layer in the bladder base but were rarely seen in the lateral wall, which contained nNOS⁺ BUCs. No nNOS⁺ BUCs and cGMP⁺ SU-ICs were apparent in the dome. The degree of complexity in nNOS distribution and NO target cells is therefore greater than has previously been described and may reflect distinct physiological functions that have yet to be identified.     

The influence of a cellular size distribution on NMR diffusion measurements

In the magnetic resonance community, the usefulness of diffusion-weighted imaging is undisputed. However, the correct interpretation of multicomponent diffusion is not widely agreed upon, and progress in this direction is impeded by several confounding experimental results. It is thus of great importance to resolve possible interfering factors. The objective of the present study is to examine the influence of a cellular size distribution. Using the Kärger equations, numerical calculations show that even substantial cellular size variations induce only small changes in the estimated compartmental diffusion constants and volume fractions.     

Analysis of the epidermal growth factor receptor specific transcriptome: effect of receptor expression level and an activating mutation

Overexpression or expression of activating mutations of the epidermal growth factor receptor (EGFR) is common in cancer and correlates with neoplastic progression. The present study employed Affymetrix oligonucleotide arrays to profile genes induced by ligand-activated EGFR with the receptor either moderately expressed or overexpressed at an in-itself transforming level. These changes were compared to those induced by the naturally occurring constitutively active variant EGFRvIII. This study provides novel insight on the activities and mechanisms of EGFRvIII and EGFR mediated transformation, as genes encoding proteins with functions in promoting cell proliferation, invasion, antiapoptosis, and angiogenesis featured prominently in the EGFRvIII- and EGFR-expressing cells. Surprisingly, it was found that ligand-activated EGFR induced the expression of a large group of genes known to be inducible by interferons. Expression of this module was absent in the EGFRvIII-expressing cell line and the parental cell line. Treatment with the specific EGFR inhibitor AG1478 indicated that the regulations were primary, receptor-mediated events. Furthermore, activation of this module correlated with activation of STAT1 and STAT3. The results thus demonstrate that ligand-activated EGFR at different expression levels results in different kinetics of signaling and induction of gene expression. In addition, the constitutively active variant EGFRvIII seems to activate only a subset of signal pathways and induce a subset of genes as compared to the ligand-activated EGFR.     

The Use of Phase Inversion Temperature (PIT) Microemulsion Technology to Enhance Oil Utilisation during <Emphasis Type="Italic">Streptomyces rimosus</Emphasis> Fed-batch Fermentations to Produce Oxytetracycline

The use of a rapeseed oil emulsion feed, produced by a phase inversion temperature (PIT) process, produced more biomass, gave a 3-fold increase in oil utilisation and a higher oxytetracycline titre but a higher residual oil concentration when compared to a conventional fed-batch Streptomyces rimosus process fed with crude rapeseed oil. Importantly, microbial utilisation of the surfactant was confirmed for the first time.     

Can Neurofeedback Training Enhance Performance? An Evaluation of the Evidence with Implications for Future Research

There have been many claims regarding the possibilities of performance enhancement training. The aim of such training is for an individual to complete a specific function or task with fewer errors and greater efficiency, resulting in a more positive outcome. The present review examined evidence from neurofeedback training studies to enhance performance in a particular area. Previous research has documented associations between specific cortical states and optimum levels of performance in a range of tasks. This information provides a plausible rationale for the use of neurofeedback to train individuals to enhance their performance. An examination of the literature revealed that neurofeedback training has been utilised to enhance performance from three main areas; sport, cognitive and artistic performance. The review examined evidence from neurofeedback training studies within each of these three areas. Some suggestive findings have been reported with regard to the use of neurofeedback training to enhance performance. However, due to a range of methodological limitations and a general failure to elicit unambiguous changes in baseline EEG activity, a clear association between neurofeedback training and enhanced performance has yet to be established. Throughout, the review highlights a number of recommendations to aid and stimulate future research.     

Urban Domestic Gardens (IV): The Extent of the Resource and its Associated Features

Domestic (‘private’) gardens constitute a substantial proportion of ‘green space’ in urban areas and hence are of potential significance for the maintenance of biodiversity in such areas. However, the size and nature of this resource and its associated features are poorly known. In this study, we provide the first detailed audit, using domestic gardens in the city of Sheffield as a model study system. Domestic gardens, the mean area of which was 151 m², cover approximately 33 km² or 23% of the predominantly urban area of the city. The smaller gardens contribute disproportionately to this total because, although individually they add little, they are large in number. Conversely, the regions of the city with proportionately more garden area contribute most to the total garden area of the city, although such regions are limited in number. Based on the findings of a telephone based survey, 14.4% of dwellings with gardens were estimated to have ponds, 26% to have nest-boxes, 29% to have compost heaps, 48% to hold trees more than 3 m tall, and 14% of dwellings were estimated to be home to one or more cats. Whilst the absolute frequency of these features is low to moderate, by extrapolation they nonetheless yield estimates for domestic gardens in Sheffield of a total of 25,200 ponds, 45,500 nest boxes, 50,750 compost heaps, 360,000 trees, and a population of 52,000 domestic cats. These results are considered in the context of the role of gardens in urban areas as habitats for wildlife and the implications for housing policy.     

Increased Computational Accuracy in Multi-Compartmental Cable Models by a Novel Approach for Precise Point Process Localization

Compartmental models of dendrites are the most widely used tool for investigating their electrical behaviour. Traditional models assign a single potential to a compartment. This potential is associated with the membrane potential at the centre of the segment represented by the compartment. All input to that segment, independent of its location on the segment, is assumed to act at the centre of the segment with the potential of the compartment. By contrast, the compartmental model introduced in this article assigns a potential to each end of a segment, and takes into account the location of input to a segment on the model solution by partitioning the effect of this input between the axial currents at the proximal and distal boundaries of segments. For a given neuron, the new and traditional approaches to compartmental modelling use the same number of locations at which the membrane potential is to be determined, and lead to ordinary differential equations that are structurally identical. However, the solution achieved by the new approach gives an order of magnitude better accuracy and precision than that achieved by the latter in the presence of point process input.Action Editor: Alain Destexhe     

Potential photosynthesis gene recombination between Prochlorococcus and Synechococcus via viral intermediates

Genes (psbA and psbD) encoding for photosynthetically important proteins were recently found in a number of cultured cyanophage genomes. This phenomenon may be a beneficial trait to the viruses or their photosynthetic cyanobacterial hosts, or may represent an untapped pool of genes involved in the formation of the photosynthetic apparatus that are prone to lateral gene transfer. Here we show analyses of psbA genes from uncultured environmental viruses and prophage populations. We observe a statistically significant separation between viral genes and their potential Synechococcus hosts' genes, and statistical analyses under models of codon evolution indicate that the psbA genes of viruses are evolving under levels of purifying selection that are virtually indistinguishable from their hosts. Furthermore, our data also indicate the possible exchange and reshuffling of psbA genes between Synechococcus and Prochlorococcus via phage intermediates. Overall, these observations raise the possibility that marine viruses serve as a potential genetic pool in shaping the evolution of cyanobacterial photosynthesis.     

Successional Position of Dry Andean Dwarf Forest Species as a Basis for Restoration Trials

The successional affinity of nine woody species was inferred from the structure, diversity and disturbance history of the vegetation where these occurred. This was done in order to obtain a basis for a restoration experiment, currently in execution, in the dry Andean dwarf forest zone on the edge of the High Plain of Bogotá (Colombia), at 2600–2950 m.a.s.l. We laid out 101 relevees in grassland and shrubland types in different stages of recovery, and in relatively little disturbed endemic Condalia thomasiana dwarf forest. The disturbance history of sites over the last ~60 years was inferred from aerial photograph series (1941–1991). CCA and logistic regression were applied to relate species composition to diversity, environment and disturbance history. All species showed a preference for certain structural groups. Also, a clear relation between species occurrence and vegetation diversity was found. Baccharis macrantha, and Dalea coerulea appeared relatively tolerant to grazing, while the remaining seven species reacted negatively. Soil clay content, base availability and organic carbon content was also an important factor for occurrence of each species. Invasion of grasslands by woody species is pioneered by Baccharis macrantha and followed by Dodonaea viscosa. Dalea coerulea was predominantly found on truncated clayey soils, which will probably not support Condalia dwarf forest. The hypothesized classification of the nine planted species to either pioneers or late-successional was fine-tuned. This exploratory study will be of use in the set-up of future succession-based restoration experiments, and for converting exotics afforestations to natural vegetation.