Publications by authors named "Hansson B"

In Drosophila, the male sex pheromone cis-vaccenyl acetate (cVA) elicits aggregation and courtship, through the odorant receptor Or67d. Long-lasting exposure to cVA suppresses male courtship, via a second channel, Or65a. In females, the role of Or65a has not been studied.

View Article and Find Full Text PDF

As a model for primary olfactory perception, the antennal lobe (AL) of Drosophila melanogaster is among the most thoroughly investigated and well-understood neuronal structures. Most studies investigating the functional properties and neuronal wiring of the AL are conducted in vivo, although so far the AL morphology has been mainly analyzed in vitro. Identifying the morphological subunits of the AL-the olfactory glomeruli-is usually done using in vitro AL atlases.

View Article and Find Full Text PDF

Genetic colour polymorphisms are widespread across animals and often subjected to complex selection regimes. Traditionally, colour morphs were used as simple visual markers to measure allele frequency changes in nature, selection, population divergence and speciation. With advances in sequencing technology and analysis methods, several model systems are emerging where the molecular targets of selection are being described.

View Article and Find Full Text PDF

Background: There is growing interest in odonates (damselflies and dragonflies) as model organisms in ecology and evolutionary biology but the development of genomic resources has been slow. So far only one draft genome (Ladona fulva) and one transcriptome assembly (Enallagma hageni) have been published. Odonates have some of the most advanced visual systems among insects and several species are colour polymorphic, and genomic and transcriptomic data would allow studying the genomic architecture of these interesting traits and make detailed comparative studies between related species possible.

View Article and Find Full Text PDF

Inbreeding increases homozygosity, exposes genome-wide recessive deleterious alleles and often reduces fitness. The physiological and reproductive consequences of inbreeding may be manifested already during gene regulation, but the degree to which inbreeding influences gene expression is unknown in most organisms, including in birds. To evaluate the pattern of inbreeding-affected gene expression over the genome and in relation to sex, we performed a transcriptome-wide gene expression (10 695 genes) study of brain tissue of 10-day-old inbred and outbred, male and female zebra finches.

View Article and Find Full Text PDF

Odorant receptors (ORs) detect volatile molecules and transform this external information into an intracellular signal. Insect ORs are heteromers composed of two seven transmembrane proteins, an odor-specific OrX and a coreceptor (Orco) protein. These ORs form ligand gated cation channels that conduct also calcium.

View Article and Find Full Text PDF

Phytophagous insects use blends of volatiles released from plants to select hosts for feeding and oviposition. To behaviorally analyze complex blends, we need efficient and selective methods for elucidating neuron types, their ligands, and specificity. Gas chromatography-combined single sensillum recordings (GC-SSRs) from antennal olfactory sensilla of female moth, Spodoptera littoralis revealed 38 physiologically active peaks in the headspace volatile blends from both larvae-damaged cotton plants and lilac flowers.

View Article and Find Full Text PDF

Most naturally occurring olfactory signals do not consist of monomolecular odorants but, rather, are mixtures whose composition and concentration ratios vary. While there is ample evidence for the relevance of complex odor blends in ecological interactions and for interactions of chemicals in both peripheral and central neuronal processing, a fine-scale analysis of rules governing the innate behavioral responses of Drosophila melanogaster towards odor mixtures is lacking. In this study we examine whether the innate valence of odors is conserved in binary odor mixtures.

View Article and Find Full Text PDF

The hawkmoth, Manduca sexta, has been a keystone system for developmental, neurobiological, and ecological studies for several decades. Because many of its behaviors are driven by olfactory cues, a thorough understanding of the Manduca olfactory system is essential to studying its biology. With the aim of functionally characterizing single antennal olfactory sensory neurons (OSNs) and determining their detailed topographic location, we performed systematic single-sensillum recordings on 4 morphological types of olfactory sensilla: trichoid-A and -B and basiconic-A and -B.

View Article and Find Full Text PDF

Lion fecal DNA extracts from four individuals each from Yankari Game Reserve and Kainji-Lake National Park (central northeast and west Nigeria, respectively) were Sanger-sequenced for the mitochondrial cytochrome b gene. The sequences were aligned against 61 lion reference sequences from other parts of Africa and India. The sequence data were analyzed further for the construction of phylogenetic trees using the maximum-likelihood approach to depict phylogenetic patterns of distribution among sequences.

View Article and Find Full Text PDF

Conclusion: No statistically significant 5-year survival difference was seen in patients with oral and oropharyngeal squamous cell carcinoma (OOPSCC) between high-risk HPV-positive and -negative groups in this population-based study.

Objectives: To see if the formerly observed higher risk for recurrence or second primary tumour (SPT) in high-risk HPV-positive patients with OOPSCC corresponds to worse survival.

Methods: A total of 128 consecutive, previously untreated patients with OOPSCC, who were part of a population-based case-control study in southern Sweden during 2000-2004, were included.

View Article and Find Full Text PDF

Crustaceans have successfully adapted to a variety of environments including fresh- and saltwater as well as land. Transition from an aquatic to a terrestrial lifestyle required adaptations of the sensory equipment of an animal, particularly in olfaction, where the stimulus itself changes from hydrophilic to mainly hydrophobic, air-borne molecules. Hermit crabs Coenobita spp.

View Article and Find Full Text PDF

The ability of a specialized herbivore to overcome the chemical defense of a particular plant taxon not only makes it accessible as a food source but may also provide metabolites to be exploited for communication or chemical defense. Phyllotreta flea beetles are adapted to crucifer plants (Brassicales) that are defended by the glucosinolate-myrosinase system, the so-called "mustard-oil bomb." Tissue damage caused by insect feeding brings glucosinolates into contact with the plant enzyme myrosinase, which hydrolyzes them to form toxic compounds, such as isothiocyanates.

View Article and Find Full Text PDF

Purpose: Possible selves are conceptions of our selves in future states. Previous findings indicated that women with anorexia nervosa tended to have more negative possible selves than a control group, even when rating future situations normally regarded in our society as desirable. The present study investigated whether this was a general pattern in women with eating disorders, relating findings on possible selves to depression.

View Article and Find Full Text PDF

Desert ants feeding on dead arthropods forage for food items that are distributed unpredictably in space and time in the food-scarce terrain of the Saharan salt pans [1]. Scavengers of the genus Cataglyphis forage individually and do not lay pheromone trails [2]. They rely primarily on path integration [3] for navigation and, in addition, use visual [4] and olfactory cues [5-7].

View Article and Find Full Text PDF

The olfactory sense detects a plethora of behaviorally relevant odor molecules; gene families involved in olfaction exhibit high diversity in different animal phyla. Insects detect volatile molecules using olfactory (OR) or ionotropic receptors (IR) and in some cases gustatory receptors (GRs). While IRs are expressed in olfactory organs across Protostomia, ORs have been hypothesized to be an adaptation to a terrestrial insect lifestyle.

View Article and Find Full Text PDF

Insect odorant receptors (ORs) are heteromeric complexes of an odor-specific receptor protein (OrX) and a ubiquitous co-receptor protein (Orco). The ORs operate as non-selective cation channels, also conducting Ca(2+) ions. The Orco protein contains a conserved putative calmodulin (CaM)-binding motif indicating a role of CaM in its function.

View Article and Find Full Text PDF

Genetically polymorphic species offer the possibility to study maintenance of genetic variation and the potential role for genetic drift in population divergence. Indirect inference of the selection regimes operating on polymorphic traits can be achieved by comparing population divergence in neutral genetic markers with population divergence in trait frequencies. Such an approach could further be combined with ecological data to better understand agents of selection.

View Article and Find Full Text PDF

Background: In a rapidly changing world, it is of fundamental importance to understand processes constraining or facilitating adaptation through microevolution. As different traits of an organism covary, genetic correlations are expected to affect evolutionary trajectories. However, only limited empirical data are available.

View Article and Find Full Text PDF

Odor information is predominantly perceived as complex odor blends. For Drosophila melanogaster one of the most attractive blends is emitted by an over-ripe banana. To analyze how the fly's olfactory system processes natural blends we combined the experimental advantages of gas chromatography and functional imaging (GC-I).

View Article and Find Full Text PDF

Evolutionary molecular studies of island radiations may lead to insights in the role of vicariance, founder events, population size and drift in the processes of population differentiation. We evaluate the degree of population genetic differentiation and fixation of the Canary Islands blue tit subspecies complex using microsatellite markers and aim to get insights in the population history using coalescence based methods. The Canary Island populations were strongly genetically differentiated and had reduced diversity with pronounced fixation including many private alleles.

View Article and Find Full Text PDF

Why are some odors perceived as pleasant while others are not? We review current research on how pleasant and unpleasant odors, that is, odors with positive or negative valence, are processed in the brain of flies and mice. We conclude that in mice pleasant and unpleasant odors are detected via three olfactory subsystems with only one being fully dedicated to unpleasant odors, while the others detect both good and bad odors. Correspondingly, so far no clear segmentation into regions processing exclusively pleasant or unpleasant odors has been identified in the mouse brain.

View Article and Find Full Text PDF
Article Synopsis
  • Crustaceans have adapted to various habitats, including a significant transition from water to land seen in at least five lineages, requiring changes in sensory organs, particularly the first pair of antennae used for smell.
  • This study focused on the molecular differences in antennulae of the land hermit crab Coenobita clypeatus and the marine hermit crab Pagurus bernhardus by sequencing and comparing their antennal transcriptomes.
  • Findings revealed a high similarity in the expressed genes, with both species relying on similar ionotropic receptors (IRs) for olfactory detection, and no significant genetic shift associated with their habitat change.
View Article and Find Full Text PDF

After herbivory, plants release volatile organic compounds from damaged foliage as well as from nearby undamaged leaves that attract herbivore enemies. Little is known about what controls the volatile emission differences between damaged and undamaged tissues and how these affect the orientation of herbivore enemies. We investigated volatile emission from damaged and adjacent undamaged foliage of black poplar (Populus nigra) after herbivory by gypsy moth (Lymantria dispar) caterpillars and determined the compounds mediating the attraction of the gypsy moth parasitoid Glyptapanteles liparidis (Braconidae).

View Article and Find Full Text PDF