Concurrent modulation of neuronal and behavioural olfactory responses to sex and host plant cues in a male moth

Mating has profound effects on animal physiology and behaviour, not only in females but also in males, which we show here for olfactory responses. In cotton leafworm moths, Spodoptera littoralis, odour-mediated attraction to sex pheromone and plant volatiles are modulated after mating, producing a behavioural response that matches the physiological condition of the male insect. Unmated males are attracted by upwind flight to sex pheromone released by calling females, as well as to volatiles of lilac flowers and green leaves of the host plant cotton, signalling adult food and mating sites, respectively. Mating temporarily abolishes male attraction to females and host plant odour, but does not diminish attraction to flowers. This behavioural modulation is correlated with a response modulation in the olfactory system, as shown by electro-physiological recordings from antennae and by functional imaging of the antennal lobe, using natural odours and synthetic compounds. An effect of mating on the olfactory responses to pheromone and cotton plant volatiles but not to lilac flowers indicates the presence of functionally independent neural circuits within the olfactory system. Our results indicate that these circuits interconnect and weigh perception of social and habitat odour signals to generate appropriate behavioural responses according to mating state.     

Low-dose carbon monoxide reduces airway hyperresponsiveness in mice

Carbon monoxide (CO) in expired gas has been shown to be elevated with asthma; however, its function is not known, and there is some potential that it may serve a bronchoprotective role to decrease airway hyperresponsiveness (AHR). Thus the ability of CO to reverse methacholine (MCh)-induced bronchoconstriction was evaluated in C57BL/6 (C57) and A/J mice with and without airway inflammation produced by ovalbumin (OVA). Acutely administered CO (1% in air, 10 min) reduced MCh-driven increases in lung resistance in OVA-challenged C57 mice by an average of 50% (from 14.5 to 7.1 cmH2O.ml-1.s-1), whereas no effect was observed in na?ve C57 mice or OVA-challenged C57 mice inhaling air alone. Acutely inhaled CO (500 ppm = 0.05%, for 10 min) reduced MCh-induced airway reactivity (AR) by 20-60% in airway hyperresponsive na?ve A/J mice, whereas repeated 10-min administrations of 500 ppm CO over a 5-day period decreased AR by 50%. Repeated administration of low-dose CO [250 (0.025%) and (0.05%) 500 ppm, 1 h/day, 5 days] to A/J mice with airway inflammation likewise resulted in a drop of AR by 50%, compared with those not receiving CO. Inhibition of guanylyl cyclase/guanosine 3',5'-cyclic monophosphothioate (cGMP) using 1H-[1,2,4] oxydiazolo[4,3-a]quinoxalin-1-one or a competitive inhibitor, Rp diastereomers of 8-bromo-cGMP, resulted in inhibition of the effect of CO on AHR, suggesting that the effects of CO were mediated through this mechanism. These results indicate that low-dose CO can effectively reverse AHR in the presence and absence of airway inflammation in mice and suggest a potential role for CO in the modulation of AHR.     

A virtual tour of the Guide for zebrafish users

PHS-funded and AAALAC-accredited facilities are required to use the Guide as the basis for setting up a zebrafish care and use program. The authors describe how they accomplished this task at the University of Oregon Zebrafish Facility.     

Identification of metabolites of fluorine-18-labeled M2 muscarinic receptor agonist, 3-(3-[(3-fluoropropyl)thio]-1,2,5-thiadiazol-4-yl)-1,2,5,6-tetrahydro-1-methylpyridine, produced by human and rat hepatocytes

An accurate, rapid method for the determination of unmetabolized 3-(3-[(3-[18F]fluoropropyl)thio]-1,2,5-thiadiazol-4-yl)-1.2,5,6-tetrahydro-1-methylpyridine (FP-TZTP), a selective M2 muscarinic agonist, is necessary in order to obtain quantitative information from positron emission tomography (PET) imaging. Using LC-MS-MS to analyze products from cultured human and rat hepatocytes, we identified metabolites resulting from oxidation of the nitrogen in the tetrahydropyridine ring, sulfur-oxidation, demethylation of the tertiary amine, and oxidation of the tetrahydropyridine ring. From the knowledge of the structure of the metabolites, we have developed a two-step extraction sequence that allows rapid determination of the parent fraction in plasma without time-consuming chromatographic analysis.     

A rapid and noninvasive method for detecting tissue-limited mosaicism: detection of i(12)(p10) in buccal smear from a child with Pallister-Killian syndrome

Pallister-Killian syndrome (PKS), a rare disorder, is characterized by tissue-limited or tissue-specific mosaicism. The characteristic chromosome abnormality associated with PKS is i(12p), which is seen predominantly in skin fibroblast cultures. Diagnosis of i(12p) has been carried out on buccal smears before and was shown to be an easy and feasible method. All previously published studies used alpha-satellite probes for the diagnosis and as such have several pitfalls. Our approach, using dual-color, locus-specific probes, has high specificity and sensitivity for the diagnosis of i(12p). Using statistical analysis, we have also confirmed that the signal pattern in interphase nuclei is consistent with isochromosome 12p.     

Interaction with heparin and matrix metalloproteinase 2 cleavage expose a cryptic anti-adhesive site of fibronectin

We recently found that fibronectin (FN) had a functional site [YTIYVIAL sequence in the heparin-binding domain 2 (Hep 2)] that was capable of suppressing the integrin-mediated cell adhesion to extracellular matrix. However, our results also indicated that this anti-adhesive site seemed to be usually buried within the Hep 2 domain structure because of its hydrophobic nature, raising a question as to the physiological significance of the cryptic anti-adhesive activity of FN. The present study demonstrates that the cryptic anti-adhesive activity can be exposed through the physiological processes. A 30-kDa chymotryptic FN fragment derived from Hep 2 domain (Hep 2 fragment), which had no effect on adhesion of MSV-transformed nonproducer 3T3 cell line (KN(7)8) to FN, expressed the anti-adhesive activity after treatment with 6 M urea. Light scattering and circular dichroism measurements showed that the urea treatment induced the conformational change of the Hep 2 fragment from a more compact form to an unfolded one. Incubation of the Hep 2 fragment with heparin also induced similar conformational changes and expression of anti-adhesive activity. Additionally, both the urea and heparin treatments made the Hep 2 fragment and intact FN much more accessible to the polyclonal antibody (alphaIII14A), with a recognition site near the anti-adhesive site of FN. Specific cleavage of either the Hep 2 fragment or intact FN by matrix metalloproteinase 2 (MMP-2) released a 10-kDa fragment with the anti-adhesive activity, which was shown to have the exposed anti-adhesive site on the amino-terminal region. Thus, the cryptic anti-adhesive activity of FN can be expressed upon conformational change and proteolytic cleavage of Hep 2 domain.     

Synthesis and characterization of the asymmetrically coordinated dinuclear complex [{L(Ph2acac)FeIII}(μ-O){FeIII(Cl4-cat)L}](ClO4) and its one-electron reduced and oxidized forms. Models for dinuclear non-heme active sites

The asymmetrically coordinated complex [{L(Ph₂acac)Fe^III}(μ-O){Fe^III(Cl₄-cat)L}](BPh₄)·1.5toluene has been synthesized and structurally characterized (Ph₂acac^–=1,3-diphenylpropane-1,3-dionate, Cl₄-cat^2–=tetrachlorocatecholate, L=1,4,7-trimethyl-1,4,7-triazacyclononane). This species can be electrochemically oxidized and reduced by one electron, respectively, yielding two species which both have an S=1/2 ground state. It is shown that the oxidation is ligand-centered, affording a coordinated semiquinonate(1–) ligand with S=1/2 which is antiferromagnetically coupled to a high-spin Fe^III ion (S=5/2) yielding an S=2 state which, in turn, is antiferromagnetically coupled (through the oxo bridge) to the second high-spin Fe^III ion (S=5/2) yielding the observed S=1/2 ground state. In contrast, the reduction is metal-centered generating a mixed-valent species with an [Fe^III-O-Fe^II]³⁺ core; intramolecular antiferromagnetic coupling again produces an S=1/2 ground state. The symmetrical complex [{LFe^III(Ph₂acac)}₂(μ-O)](ClO₄)₂ has also been synthesized, as have the mononuclear species [LFe^II(Ph₂acac)Cl] and [LFe^III(aacac)Cl](ClO₄)·1 mesitylene [aacac^–=3-(9-anthryl)acetylacetonate(1–)], all of which have been characterized by X-ray crystallography. The magnetism, the Mössbauer-, EPR-, and UV-VIS-spectra and the electrochemistry of complexes are reported.     

Cryptic paraflagellar rod in endosymbiont-containing kinetoplastid protozoa

Cilia and flagella are central to many biological processes in a diverse range of organisms. The kinetoplastid protozoa are very appealing models for the study of flagellar function, particularly in the light of the availability of extensive trypanosomatid genome information. In addition to the highly conserved 9 + 2 axoneme, the kinetoplastid flagellum contains a characteristic paraflagellar rod structure (PFR). The PFR is necessary for full motility and provides support for metabolic regulators that may influence flagellar beating. However, there is an intriguing puzzle: one clade of endosymbiont-containing kinetoplastids apparently lack a PFR yet are as motile as species that possess a PFR and are able to attach to the invertebrate host epithelia. We investigated how these organisms are able to locomote despite the apparent lack of PFR. Here we have identified a PFR1 gene in the endosymbiont-bearing trypanosome Crithidia deanei. This gene is expressed in C. deanei and is able to partially complement a pfr1 null mutation in Leishmania mexicana cells, demonstrating that the encoded protein is functional. Careful reexamination of C. deanei flagellar ultrastructure revealed a greatly reduced PFR missed by many previous analyses. This affirms the PFR as a canonical organelle of kinetoplastids. Moreover, although PFR proteins have been conserved in evolution, primary sequence differences contribute to particular PFR morphotypes characteristic of different kinetoplastid species.