Comparing peripheral olfactory coding with host preference in the rhagoletis species complex

Recent studies have shown that flies from sympatric populationsof Rhagoletis pomonella infesting hawthorn, apple, and floweringdogwood fruit can distinguish among unique volatile blends identifiedfrom each host. Analysis of peripheral chemoreception in Rhagoletisflies suggests that changes in receptor specificity and/or receptorneuron sensitivity could impact olfactory preference among thehost populations and their hybrids. In an attempt to validatethese claims, we have combined flight tunnel analyses and singlesensillum electrophysiology in F₂ and backcross hybrids displayinga variety of behavioral phenotypes. Results show that differencesin peripheral chemoreception among second-generation adultsdo not provide a direct correlation between peripheral codingand olfactory behavior. We conclude that either the plasticityof the central nervous system in Rhagoletis can compensate forsignificant alterations in peripheral coding or that peripheralchanges present subtle effects on behavior not easily detectablewith current techniques. The results of this study imply thatthe basis for olfactory behavior in Rhagoletis has a complicatedgenetic and neuronal basis, even for populations with a recentdivergence in preference.     

Investigation of breathing parameters during odor perception and olfactory imagery

Compared with visual and auditory imagery, little is known aboutolfactory imagery. There is evidence that respiration may bealtered by both olfactory perception and olfactory imagery.In order to investigate this relationship, breathing parameters(respiratory minute volume, respiratory amplitude, and breathingrate) in human subjects during olfactory perception and olfactoryimagery were investigated. Fifty-six subjects having normalolfactory function were tested. Nasal respiration was measuredusing a respiratory pressure sensor. Using an experimental blockdesign, we alternately presented odors or asked the subjectsto imagine a given smell. Four different pleasant odors wereused: banana, rose, coffee, and lemon odor. We detected a significantincrease in respiratory minute volume between olfactory perceptionand the baseline condition as well as between olfactory imageryand baseline condition. Additionally we found significant differencesin the respiratory amplitude between imagery and baseline conditionand between odor and imagery condition. Differences in the breathingrate between olfactory perception, olfactory imagery, and baselinewere not statistically significant. We conclude from our resultsthat olfactory perception and olfactory imagery both have effectson the human respiratory profile and that these effects arebased on a common underlying mechanism.     

The Secretin GPCRs descended from the family of Adhesion GPCRs

The Adhesion G-protein-coupled receptors (GPCRs) are the most complex gene family among GPCRs with large genomic size, multiple introns, and a fascinating flora of functional domains, though the evolutionary origin of this family has been obscure. Here we studied the evolution of all class B (7tm2)-related genes, including the Adhesion, Secretin, and Methuselah families of GPCRs with a focus on nine genomes. We found that the cnidarian genome of Nematostella vectensis has a remarkably rich set of Adhesion GPCRs with a broad repertoire of N-terminal domains although this genome did not have any Secretin GPCRs. Moreover, the single-celled and colony-forming eukaryotes Monosiga brevicollis and Dictyostelium discoideum contain Adhesion-like GPCRs although these genomes do not have any Secretin GPCRs suggesting that the Adhesion types of GPCRs are the most ancient among class B GPCRs. Phylogenetic analysis found Adhesion group V (that contains GPR133 and GPR144) to be the closest relative to the Secretin family in the Adhesion family. Moreover, Adhesion group V sequences in N. vectensis share the same splice site setup as the Secretin GPCRs. Additionally, one of the most conserved motifs in the entire Secretin family is only found in group V of the Adhesion family. We suggest therefore that the Secretin family of GPCRs could have descended from group V Adhesion GPCRs. We found a set of unique Adhesion-like GPCRs in N. vectensis that have long N-termini containing one Somatomedin B domain each, which is a domain configuration similar to that of a set of Adhesion-like GPCRs found in Branchiostoma floridae. These sequences show slight similarities to Methuselah sequences found in insects. The extended class B GPCRs have a very complex evolutionary history with several species-specific expansions, and we identified at least 31 unique N-terminal domains originating from other protein classes. The overall N-terminal domain structure, however, concurs with the phylogenetic analysis of the transmembrane domains, thus enabling us to track the origin of most of the subgroups.     

DNA aptamers developed against a soman derivative cross‐react with the methylphosphonic acid core but not with flanking hydrophobic groups

Twelve rounds of systematic evolution of ligands by exponential enrichment (SELEX) were conducted against a magnetic bead conjugate of the para‐aminophenylpinacolylmethylphosphonate (PAPMP) derivative of the organophosphorus (OP) nerve agent soman (GD). The goal was to develop DNA aptamers that could scavenge GD in vivo, thereby reducing or eliminating the toxic effects of this dangerous compound. Aptamers were sequenced and screened in peroxidase‐based colorimetric plate assays after rounds 8 and 12 of SELEX. The aptamer candidate sequences exhibiting the highest affinity for the GD derivative from round 8 also reappeared in several clones from round 12. Each of the highest affinity PAPMP‐binding aptamers also bound methylphosphonic acid (MPA). In addition, the aptamer with the highest overall affinity for PAPMP carried a sequence motif (TTTAGT) thought to bind MPA based on previously published data (J. Fluoresc 18: 867–876, 2008). This sequence motif was found in several other relatively high affinity PAPMP aptamer candidates as well. In studies with the nerve agent GD, pre‐incubation of a large molar excess of aptamer candidates failed to protect human butyrylcholinesterase (BuChE) from inhibition. With the aid of three‐dimensional molecular modeling of the GD derivative it appears that a hydrophilic cleft sandwiched between the pinacolyl group and the p‐aminophenyl ring might channel nucleotide interactions to the phosphonate portion of the immobilized GD derivative. However, bona fide GD free in solution may be repulsed by the negative phosphate backbone of aptamers and rotate its phosphonate and fluorine moieties away from the aptamer to avoid being bound. Future attempts to develop aptamers to GD might benefit from immobilizing the pinacolyl group of bona fide GD to enhance exposure of the phosphonate and fluorine to the random DNA library. Copyright © 2008 John Wiley & Sons, Ltd.     

A global view of protein expression in human cells,tissues, and organs

Defining the protein profiles of tissues and organs is critical to understanding the unique characteristics of the various cell types in the human body. In this study, we report on an anatomically comprehensive analysis of 4842 protein profiles in 48 human tissues and 45 human cell lines. A detailed analysis of over 2 million manually annotated, high‐resolution, immunohistochemistry‐based images showed a high fraction (>65%) of expressed proteins in most cells and tissues, with very few proteins (<2%) detected in any single cell type. Similarly, confocal microscopy in three human cell lines detected expression of more than 70% of the analyzed proteins. Despite this ubiquitous expression, hierarchical clustering analysis, based on global protein expression patterns, shows that the analyzed cells can be still subdivided into groups according to the current concepts of histology and cellular differentiation. This study suggests that tissue specificity is achieved by precise regulation of protein levels in space and time, and that different tissues in the body acquire their unique characteristics by controlling not which proteins are expressed but how much of each is produced.     

Succinic acid amides as P2–P3 replacements for inhibitors of interleukin-1β converting enzyme (ICE or caspase 1)

Succinic acid amides have been found to be effective P2–P3 scaffold replacements for peptidic ICE inhibitors. Heteroarylalkyl fragments occupying the P4 position provided access to compounds with nM affinities. Utilization of an acylal prodrug moiety was required to overcome biopharmaceutical issues which led to the identification of 17f, a potential clinical candidate.     

Ovalbumin sensitization and challenge increases the number of lung cells possessing a mesenchymal stromal cell phenotype

Background

Recent studies have indicated the presence of multipotent mesenchymal stromal cells (MSCs) in human lung diseases. Excess airway smooth muscle, myofibroblasts and activated fibroblasts have each been noted in asthma, suggesting that mesenchymal progenitor cells play a role in asthma pathogenesis. We therefore sought to determine whether MSCs are present in the lungs of ovalbumin (OVA)-sensitized and challenged mice, a model of allergic airways disease.

Methods

Balb/c mice were sensitized and challenged with PBS or OVA over a 25 day period. Flow cytometry as well as colony forming and differentiation potential were used to analyze the emergence of MSCs along with gene expression studies using immunochemical analyses, quantitative polymerase chain reaction (qPCR), and gene expression beadchips.

Results

A CD45-negative subset of cells expressed Stro-1, Sca-1, CD73 and CD105. Selection for these markers and negative selection against CD45 yielded a population of cells capable of adipogenic, osteogenic and chondrogenic differentiation. Lungs from OVA-treated mice demonstrated a greater average colony forming unit-fibroblast (CFU-F) than control mice. Sorted cells differed from unsorted lung adherent cells, exhibiting a pattern of gene expression nearly identical to bone marrow-derived sorted cells. Finally, cells isolated from the bronchoalveolar lavage of a human asthma patient showed identical patterns of cell surface markers and differentiation potential.

Conclusions

In summary, allergen sensitization and challenge is accompanied by an increase of MSCs resident in the lungs that may regulate inflammatory and fibrotic responses.