Selective inhibition of prostaglandin biosynthesis by gold salts and phenylbutazone

Gold salts and phenylbutazone selectively inhibit the synthesis of PGF_2α and PGE₂ respectively. Lowered production of one prostaglandin species is accompanied by an increased production of the other. Selective inhibition by these drugs was observed in the presence of adrenaline, reduced glutathione and copper sulphate under conditions when most anti-inflammatory compounds inhibited PGE₂ and PGF_2α syntheses equally. It is postulated that selective inhibitors may have a different mode of action and beneficial effects may be related to the endogenous ratio of PGE to PGF required for normal function.     

Evidence for Enhanced Multisensory Facilitation with Stimulus Relevance: An Electrophysiological Investigation

Currently debate exists relating to the interplay between multisensory processes and bottom-up and top-down influences. However, few studies have looked at neural responses to newly paired audiovisual stimuli that differ in their prescribed relevance. For such newly associated audiovisual stimuli, optimal facilitation of motor actions was observed only when both components of the audiovisual stimuli were targets. Relevant auditory stimuli were found to significantly increase the amplitudes of the event-related potentials at the occipital pole during the first 100 ms post-stimulus onset, though this early integration was not predictive of multisensory facilitation. Activity related to multisensory behavioral facilitation was observed approximately 166 ms post-stimulus, at left central and occipital sites. Furthermore, optimal multisensory facilitation was found to be associated with a latency shift of induced oscillations in the beta range (14–30 Hz) at right hemisphere parietal scalp regions. These findings demonstrate the importance of stimulus relevance to multisensory processing by providing the first evidence that the neural processes underlying multisensory integration are modulated by the relevance of the stimuli being combined. We also provide evidence that such facilitation may be mediated by changes in neural synchronization in occipital and centro-parietal neural populations at early and late stages of neural processing that coincided with stimulus selection, and the preparation and initiation of motor action.     

Reduced endothelial nitric oxide synthase in lungs of chronically ventilated preterm lambs

Nitric oxide (NO), produced in lung vascular endothelium and airway epithelium, has an important role in regulating smooth muscle cell growth and tone. Chronic lung disease, a frequent complication of premature birth, is characterized by excess abundance, tone, and reactivity of smooth muscle in the pulmonary circulation and conducting airways, leading to increased lung vascular and airway resistance. Whether these structural and functional changes are associated with diminished pulmonary expression of endothelial nitric oxide synthase (eNOS) protein is unknown. Both quantitative immunoblot analysis and semiquantitative immunohistochemistry showed that there was less eNOS protein in the endothelium of small intrapulmonary arteries and epithelium of small airways of preterm lambs that were mechanically ventilated for 3 wk compared with control lambs born at term. No significant differences were detected for other proteins (inducible NOS, alpha-smooth muscle actin, and pancytokeratin). Lung vascular and respiratory tract resistances were greater in the chronically ventilated preterm lambs compared with control term lambs. These results support the notion that decreased eNOS in the pulmonary circulation and respiratory tract of preterm lambs may contribute to the pathophysiology of chronic lung disease.     

Resuscitation of Salmonella enterica serovar typhimurium and enterohemorrhagic Escherichia coli from the viable but nonculturable state by heat-stable enterobacterial autoinducer

Salmonella enterica serovar Typhimurium and enterohemorrhagic Escherichia coli were stressed by prolonged incubation in water microcosms until it was no longer possible to observe colony formation when samples were plated on nonselective medium. Overnight incubation of samples in nutrient-rich broth medium supplemented with growth factors, however, allowed resuscitation of stressed and viable but nonculturable cells so that subsequent plating yielded observable colonies for significantly extended periods of time. The growth factors were (i) the trihydroxamate siderophore ferrioxamine E (for Salmonella only), (ii) the commercially available antioxidant Oxyrase, and (iii) the heat-stable autoinducer of growth secreted by enterobacterial species in response to norepinephrine. Analysis of water microcosms with the Bioscreen C apparatus confirmed that these supplements enhanced recovery of cells in stressed populations; enterobacterial autoinducer was the most effective, promoting resuscitation in populations that were so heavily stressed that ferrioxamine E or Oxyrase had no effect. Similar results were observed in Bioscreen analysis of bacterial populations stressed by heating. Patterns of resuscitation of S. enterica serovar Typhimurium rpoS mutants from water microcosms and heat stress were qualitatively similar, suggesting that the general stress response controlled by the sigma(s) subunit of RNA polymerase plays no role in autoinducer-dependent resuscitation. Enterobacterial autoinducer also resuscitated stressed populations of Citrobacter freundii and Enterobacter agglomerans.     

Specificity of catecholamine-induced growth in Escherichia coli O157:H7, Salmonella enterica and Yersinia enterocolitica

The present study demonstrates that catecholamine responsiveness in Yersinia enterocolitica, a bacterial pathogen whose infectious spectrum is principally limited to the gut, is limited to norepinephrine and dopamine, and not epinephrine; this behavior contrasts with observations for two pathogens with a wider extra-gastrointestinal spectrum, Escherichia coli O157:H7 and Salmonella enterica, which respond to all three catecholamines. Epinephrine showed lower potency than norepinephrine and dopamine in inducing growth of E. coli and S. enterica, and was a potent antagonist of norepinephrine and dopamine growth responsiveness in Y. enterocolitica. Given that only norepinephrine and dopamine and not epinephrine-containing neurons are found with the enteric nervous system, the results suggest that certain of the more exclusive enteric pathogens may have developed response systems preferentially for those neuroendocrine hormones that are produced by the enteric nervous system as host-derived signals by which to sense the environment and initiate pathogenic processes.     

Diesel exhaust particulate matter induces multinucleate cells and zinc transporter-dependent apoptosis in human airway cells

The cellular effects of biodiesel emissions particulate matter (BDEP) and petroleum diesel emissions particulate matter (PDEP) were compared using a human airway cell line, A549. At concentrations of 25 microg/ml, diesel particulate matter induced the formation of multinucleate cells. In cells treated with a mixture of 80% PDEP:20% BDEP, 52% of cells were multinucleate cells compared with only 16% of cells treated with 20% PDEP:80% BDEP with a background multinucleate rate of 7%. These results demonstrate a causal relation between the formation of multinucleate cells and exposure to exhaust particulate matter, in particular diesel exhaust. Exposure of A549 cells to PDEP induced apoptosis, seen by active caspase-3 expression and the presence of cleaved pancytokeratin. PDEP exhaust was a much stronger inducer of cellular death through apoptosis than BDEP. There was an eightfold increase in the expression of SLC30A3 (zinc transporter-3 or ZnT3) in cells exposed to 80% PDEP:20% BDEP compared to untreated cells. The increase in ZnT3 expression seen in apoptotic cells following PDEP suggests a role for this zinc transporter in the apoptotic pathway, possibly through controlling zinc fluxes. As exposure to diesel exhaust particles is associated with asthma and apoptosis in airway cells, diesel exhaust particles may directly contribute to asthma by inducing epithelial cell death through apoptotic pathway.     

Radiation of the Tnt1 retrotransposon superfamily in three Solanaceae genera

Background  

Tnt1 was the first active plant retrotransposon identified in tobacco after nitrate reductase gene disruption. The Tnt1 superfamily comprises elements from Nicotiana (Tnt1 and Tto1) and Lycopersicon (Retrolyc1 and Tlc1) species. The study presented here was conducted to characterise Tnt1-related sequences in 20 wild species of Solanum and five cultivars of Solanum tuberosum.