Mapping the semantic space for the subjective experience of emotional responses to odors

Two studies were conducted to examine the nature of the verbal labels that describe emotional effects elicited by odors. In Study 1, a list of terms selected for their relevance to describe affective feelings induced by odors was assessed while participants were exposed to a set of odorant samples. The data were submitted to a series of exploratory factor analyses to 1) reduce the set of variables to a smaller set of summary scales and 2) get a preliminary sense of the differentiation of affective feelings elicited by odors. The goal of Study 2 was to replicate the findings of Study 1 with a larger sample of odorant samples and participants and to validate the preliminary model obtained in Study 1 by using confirmatory factor analysis. Overall, the findings point to a structure of affective responses to odors that differs from the classical taxonomies of emotion such as posited by discrete or bidimensional emotion theories. These findings suggest that the subjective affective experiences or feelings induced by odors are structured around a small group of dimensions that reflect the role of olfaction in well-being, social interaction, danger prevention, arousal or relaxation sensations, and conscious recollection of emotional memories.     

Subcutaneous graft of D1 mouse mesenchymal stem cells leads to the formation of a bone-like structure

Mesenchymal stem cells (MSC) are capable of both self-renewal and multi-lineage differentiation into mesoderm-type cells such as osteoblasts, chondrocytes, adipocytes and myocytes. Together the multipotent nature of MSCs and the facility to expand them in vitro make these cells ideal resources for regenerative medicine, particularly for bone reconstruction, and therefore research efforts focused on defining efficient protocols for directing their differentiation into the requisite lineage. Despite much progress in identifying mechanisms and factors that direct and control in vitro osteogenic differentiation of MSCs, a rapid and simple model to evaluate in vivo tissue formation is still lacking. Here, we describe the unique capacity of the murine bone marrow-derived D1 MSC cell line, which differentiates in vitro into at least three cell lineages, to form in vivo a structure resembling bone. This bone-like structure was obtained after subcutaneous grafting of D1 cells into immunocompetent mice without the need of neither an osteogenic factor nor scaffold material. These data allow us to propose this cell model as a tool for exploring in vivo the mechanisms and/or factors that govern and potentially regulate osteogenesis.     

Genetic Resistance to Scrapie Infection in Experimentally Challenged Goats

In goats, several field studies have identified coding mutations of the gene encoding the prion protein (I/M₁₄₂, N/D₁₄₆, S/D₁₄₆, R/Q₂₁₁, and Q/K₂₂₂) that are associated with a lower risk of developing classical scrapie. However, the data related to the levels of resistance to transmissible spongiform encephalopathies (TSEs) of these different PRNP gene mutations are still considered insufficient for developing large-scale genetic selection against scrapie in this species. In this study, we inoculated wild-type (WT) PRNP (I₁₄₂R₁₅₄R₂₁₁Q₂₂₂) goats and homozygous and/or heterozygous I/M₁₄₂, R/H₁₅₄, R/Q₂₁₁, and Q/K₂₂₂ goats with a goat natural scrapie isolate by either the oral or the intracerebral (i.c.) route. Our results indicate that the I/M₁₄₂ PRNP polymorphism does not provide substantial resistance to scrapie infection following intracerebral or oral inoculation. They also demonstrate that H₁₅₄, Q₂₁₁, and K₂₂₂ PRNP allele carriers are all resistant to scrapie infection following oral exposure. However, in comparison to WT animals, the H₁₅₄ and Q₂₁₁ allele carriers displayed only moderate increases in the incubation period following i.c. challenge. After i.c. challenge, heterozygous K₂₂₂ and a small proportion of homozygous K₂₂₂ goats also developed the disease, but with incubation periods that were 4 to 5 times longer than those in WT animals. These results support the contention that the K₂₂₂ goat prion protein variant provides a strong but not absolutely protective effect against classical scrapie.     

Functional characterization of an LCCL-lectin domain containing protein family in Plasmodium berghei

Using bioinformatic, proteomic, immunofluorescence, and genetic cross methods, we have functionally characterized a family of putative parasite ligands as potential mediators of cell-cell interactions. We name these proteins the Limulus clotting factor C, Coch-5b2, and Lgl1 (LCCL)-lectin adhesive-like protein (LAP) family. We demonstrate that this family is conserved amongst Plasmodium spp. It possesses a unique arrangement of adhesive protein domains normally associated with extracellular proteins. The proteins are expressed predominantly, though not exclusively, in the mosquito stages of the life cycle. We test the hypothesis that these proteins are surface proteins with 1 member of this gene family, lap1, and provide evidence that it is expressed on the surface of Plasmodium berghei sporozoites. Finally, through genetic crosses of wild-type Pblap1+ and transgenic Pblap1- parasites, we show that the null phenotype previously reported for sporozoite development in a Pblap1- mutant can be rescued within a heterokaryotic oocyst and that infectious Pblap1 sporozoites can be formed. The mutant is not rescued by coparasitization of mosquitoes with a mixture Pblap1+ and Pblap1- homokaryotic oocysts.     

Simultaneous suppression of multiple genes by single transgenes. Down-regulation of three unrelated lignin biosynthetic genes in tobacco

Many reports now describe the manipulation of plant metabolism by suppressing the expression of single genes. The potential of such work could be greatly expanded if multiple genes could be coordinately suppressed. In the work presented here, we test a novel method for achieving this by using single chimeric constructs incorporating partial sense sequences for multiple genes to target suppression of two or three lignin biosynthetic enzymes. We compare this method with a more conventional approach to achieving the same end by crossing plants harboring different antisense transgenes. Our results indicate that crossing antisense plants is less straightforward and predictable in outcome than anticipated. Most progeny had higher levels of target enzyme activity than predicted and had lost the expected modifications to lignin structure. In comparison, plants transformed with the chimeric partial sense constructs had more consistent high level suppression of target enzymes and had significant changes to lignin content, structure, and composition. It was possible to suppress three target genes coordinately using a single chimeric construct. Our results indicate that chimeric silencing constructs offer great potential for the rapid and coordinate suppression of multiple genes on diverse biochemical pathways and that the technique therefore deserves to be adopted by other researchers.     

Chronic bronchial allergic inflammation increases alveolar liquid clearance by TNF-alpha -dependent mechanism

Bronchial inflammation in allergic asthma is associated with active exudation from the bronchial tree into the interstitial space of both mucosa and submucosa. The aim of this study was to evaluate epithelial and endothelial permeability as well as alveolar fluid movement in a model of chronic allergic inflammation in Brown-Norway rats sensitized and challenged with ovalbumin (OA). Control groups were challenged with saline solution (C), and rats were immunized by OA but not challenged (Se). Lung sections showed a marked inflammatory infiltrate associated with perivascular and peribronchiolar edema in OA. To measure alveolar liquid clearance, a 5% bovine albumin solution with 1 microCi of (125)I-labeled human albumin was instilled into the air spaces. Alveolar-capillary barrier permeability was evaluated by intravascular injection of 1 microCi of (131)I-labeled albumin. Endothelial permeability was significantly increased in OA, from 0.08 +/- 0.01 in the C group to 0.19 +/- 0.03 in OA group (P < 0.05). Final-to-initial protein ratio was also statistically higher in OA (1.6 +/- 0.05) compared with C (1.38 +/- 0.03, P = 0.01) and Se groups (1.42 +/- 0.03, P = 0.04). Administration of anti-tumor necrosis factor-alpha antibodies within the instillate significantly decreased this ratio (1.32 +/- 0.08, P = 0.003 vs. OA). To conclude, we demonstrated a tumor necrosis factor-alpha-dependent increase in alveolar fluid movement in a model of severe bronchial allergic inflammation associated with endothelial and epithelial leakage.     

BmBKTx1, a novel Ca2+-activated K+ channel blocker purified from the Asian scorpion Buthus martensi Karsch

BmBKTx1 is a novel short chain toxin purified from the venom of the Asian scorpion Buthus martensi Karsch. It is composed of 31 residues and is structurally related to SK toxins. However, when tested on the cloned rat SK2 channel, it only partially inhibited rSK2 currents, even at a concentration of 1 microm. To screen for other possible targets, BmBKTx1 was then tested on isolated metathoracic dorsal unpaired median neurons of Locusta migratoria, in which a wide variety of ion channels are expressed. The results suggested that BmBKTx1 could specifically block voltage-gated Ca(2+)-activated K(+) currents (BK-type). This was confirmed by testing the BmBKTx1 effect on the alpha subunits of BK channels of the cockroach (pSlo), fruit fly (dSlo), and human (hSlo), heterologously expressed in HEK293 cells. The IC(50) for channel blocking by BmBKTx1 was 82 nm for pSlo and 194 nm for dSlo. Interestingly, BmBKTx1 hardly affected hSlo currents, even at concentrations as high as 10 microm, suggesting that the toxin might be insect specific. In contrast to most other scorpion BK blockers that also act on the Kv1.3 channel, BmBKTx1 did not affect this channel as well as other Kv channels. These results show that BmBKTx1 is a novel kind of blocker of BK-type Ca(2+)-activated K(+) channels. As the first reported toxin active on the Drosophila Slo channel dSlo, it will also greatly facilitate studying the physiological role of BK channels in this model organism.