The genetics of mating recognition between Drosophila simulans and D. sechellia

During courtship, visual and chemical signals are often exchanged between the sexes. The proper exchange of such signals ensures intraspecific recognition. We have examined the genetic basis of interspecific differences in male mating behaviour and pheromone concentration between Drosophila simulans and D. sechellia by using Drosophila simulans/D. sechellia introgression lines. Our results show a majority of quantitative trait loci (QTLs) explaining variation in both male mating behaviour and pheromone concentration to be located on the third chromosome. One QTL found on the third chromosome explains variation in time needed to start courtship and copulation as well as time spent courting. The position of such QTL (approximately 84A-88B) with effects on courtship and copulation aspects of mating includes the candidate sex determination gene doublesex (84E5-6) and Voila (86E1-2), a gene that affects male courtship in D. melanogaster. One additional third chromosome QTL explained variation in 7-tricosene pheromone concentrations among males. The interval mapping position of this QTL (approximately 68E-76E) did not overlap with the position detected for differences in mating behaviour and the intervals did not include candidate genes previously identified as having an effect on D. melanogaster cuticular hydrocarbon production. We did not detect any directionality of the effect of Drosophila sechellia allele introgressions in male mating recognition.     

Spinal NTS1 receptors regulate nociceptive signaling in a rat formalin tonic pain model

Central administration of the neuropeptide neurotensin (NT) was shown to induce antinociceptive responses both spinally and supraspinally. Although NTS2 receptors play an important role in modulating the activity of spinal neurons, we have recently implicated NTS1 receptors in NT's analgesic effects in acute spinal pain paradigms. The current experiments were thus designed to examine the antinociceptive effects of intrathecal administration of NTS1 agonists in formalin-induced tonic pain in rats. We first established, using immunoblotting and immunohistochemical approaches, that NTS1 receptors were present in small- and medium-sized dorsal root ganglion cells and localized in the superficial layers of the dorsal horn of the spinal cord. We then examined the effects of intrathecal injection of NT (1–15 μg/kg) or NTS1 preferring agonists on the nocifensive response to intraplantar formalin. Both NTS1-agonists, PD149163 (10–120 μg/kg) and NT69L (1–100 μg/kg), dose-dependently attenuated the formalin-induced behaviors. Accordingly, NTS1 agonists markedly suppressed pain-evoked c- fos expression in the superficial, nucleus proprius and neck regions of the spinal dorsal horn. The concomitant administration of PD149163 with the NTS1 antagonist SR48692 (3 μg/kg) significantly reversed PD149163-induced antinociception, confirming the implication of NTS1 in tonic pain. In contrast, NT69L's analgesic effects were partly abolished by co-administration of SR48692, indicating that NT69L-induced effects may also be exerted through interaction with NTS2. These results demonstrate that NTS1 receptors play a key role in the mediation of the analgesic effects of NT in persistent pain and suggest that NTS1-selective agonists may represent a new line of analgesic compounds.     

Hyphomycetes in the River Kelvin

Summary

The hyphomycete spora of the River Kelvin and its tributary, the Allander Water, was sampled during October 1986 to January 1987. Twenty spore types were found, the commonest being Flagellospora curvula and Lemonniera aquatica. Spore numbers were high in October and declined during the autumn to an undetectable level by the end of December, but leaves collected in December and January yielded spores on incubation in water.     

IL-12 induction of mRNA encoding substance P in murine macrophages from the spleen and sites of inflammation

Substance P (SP), a neuropeptide, interacts with the neurokinin 1 receptor (NK-1R) on immune cells to help control IFN-gamma production. In murine schistosomiasis mansoni, schistosome worms produce ova that incite focal Th2-type granulomatous inflammation within the liver and intestines. Normal gut is characterized by a controlled state of inflammation. IL-10 knockout mice develop chronic Th1-type colitis spontaneously. Both schistosome granulomas and gut mucosa display an SP immune regulatory circuit. However, the origin and regulation of SP production at these sites of inflammation are poorly understood. Macrophages are a potential source of SP. We therefore studied macrophages (F4/80(+)) from these models of inflammation. SP mRNA (preprotachykinin A (PPT A)) was detected within the schistosome granuloma, spleen, and lamina propria macrophages. Compared with those from wild-type mice, granuloma macrophages from STAT6(-/-) mice had 10-fold higher PPT A mRNA expression, whereas in STAT4(-/-) animals, PPT A mRNA expression was nearly abolished. IL-12 signals via STAT4 to induce Th1-type inflammation. It was demonstrated that IL-12, but not IL-18, induces SP mRNA expression in resting splenic macrophages from Schistosoma-infected mice and in wild-type lamina propria mononuclear cells. Thus, macrophages are a source for SP at these sites of chronic inflammation, and IL-12 and STAT4 are regulators of macrophage SP mRNA expression.     

Validation of a brief telephone battery for neurocognitive assessment of patients with pulmonary arterial hypertension

Background

The effects of pulmonary arterial hypertension on brain function are not understood, despite patients'' frequent complaints of cognitive difficulties. Using clinical instruments normally administered during standard in-person assessment of neurocognitive function in adults, we assembled a battery of tests designed for administration over the telephone. The purpose was to improve patient participation, facilitate repeated test administration, and reduce the cost of research on the neuropsychological consequences of acute and chronic cardiorespiratory diseases. We undertook this study to validate telephone administration of the tests.

Methods

23 adults with pulmonary arterial hypertension underwent neurocognitive assessment using both standard in-person and telephone test administration, and the results of the two methods compared using interclass correlations.

Results

For most of the tests in the battery, scores from the telephone assessment correlated strongly with those obtained by in-person administration of the same tests. Interclass correlations between 0.5 and 0.8 were observed for tests that assessed attention, memory, concentration/working memory, reasoning, and language/crystallized intelligence (p ≤ 0.05 for each). Interclass correlations for the Hayling Sentence Completion test of executive function approached significance (p = 0.09). All telephone tests were completed within one hour.

Conclusion

Administration of this neurocognitive test battery by telephone should facilitate assessment of neuropsychological deficits among patients with pulmonary arterial hypertension living across broad geographical areas, and may be useful for monitoring changes in neurocognitive function in response to PAH-specific therapy or disease progression.     

Genome sequences of the zoonotic pathogens Chlamydia psittaci 6BC and Cal10

Chlamydia psittaci is a highly prevalent avian pathogen and the cause of a potentially lethal zoonosis, causing life-threatening pneumonia in humans. We report the genome sequences of C. psittaci 6BC, the prototype strain of the species, and C. psittaci Cal10, a widely used laboratory strain.     

Caffeine derivatives of haematin compounds

1. Caffeine reacts with haematin to form a caffeine-haematin compound that has a characteristic absorption spectrum. 2. Graphical analysis of the titration of haematin with caffeine shows that 2mol.prop. of caffeine split the dimeric haematin. 3. Thermodynamic parameters suggest that the reaction involves the making and breaking of hydrophobic bonds. 4. Graphical analysis shows dimeric haem to be split by 2mol.prop. of caffeine to yield a compound with an unusual multibanded absorption in the Soret region. 5. It is postulated that the linkage between the haem groups of dimeric haem and the haematin groups of dimeric haematin is essentially hydrophobic in nature.     

Prostaglandin E and mitogenic stimulation of human lymphocytes in serum-free medium

Sera used in cell cultures contain significant amount of prostaglandins (PGs). In order to vaoid any effects of contaminating PGs, the present study employed a serum-free culture medium and confirmed the inhibitory effect of prostaglandin E (PGE) on the human lymphocyte activation which had been observed previously employing a serum-containing medium. PGE₁ displayed a significantly stronger inhibitory effect on the cells than previously shown. Furthermore, reported enhancement of PGE synthesis by mitogen-activated lymphocytes could not be reproduced.