Individual Neurons Confined to Distinct Antennal-Lobe Tracts in the Heliothine Moth: Morphological Characteristics and Global Projection Patterns

To explore fundamental principles characterizing chemosensory information processing, we have identified antennal-lobe projection neurons in the heliothine moth, including several neuron types not previously described. Generally, odor information is conveyed from the primary olfactory center of the moth brain, the antennal lobe, to higher brain centers via projection neuron axons passing along several parallel pathways, of which the medial, mediolateral, and lateral antennal-lobe tract are considered the classical ones. Recent data have revealed the projections of the individual tracts more in detail demonstrating three main target regions in the protocerebrum; the calyces are innervated mainly by the medial tract, the superior intermediate protocerebrum by the lateral tract exclusively, and the lateral horn by all tracts. In the present study, we have identified, via iontophoretic intracellular staining combined with confocal microscopy, individual projection neurons confined to the tracts mentioned above, plus two additional ones. Further, using the visualization software AMIRA, we reconstructed the stained neurons and registered the models into a standard brain atlas, which allowed us to compare the termination areas of individual projection neurons both across and within distinct tracts. The data demonstrate a morphological diversity of the projection neurons within distinct tracts. Comparison of the output areas of the neurons confined to the three main tracts in the lateral horn showed overlapping terminal regions for the medial and mediolateral tracts; the lateral tract neurons, on the contrary, targeted mostly other output areas in the protocerebrum

Fermi Large Area Telescope Constraints on the Gamma-ray Opacity of the Universe

The Extragalactic Background Light (EBL) includes photons with wavelengths from ultraviolet to infrared, which are effective at attenuating gamma rays with energy above ~10 GeV during propagation from sources at cosmological distances. This results in a redshift- and energy-dependent attenuation of the gamma-ray flux of extragalactic sources such as blazars and Gamma-Ray Bursts (GRBs). The Large Area Telescope onboard Fermi detects a sample of gamma-ray blazars with redshift up to z~3, and GRBs with redshift up to z~4.3. Using photons above 10 GeV collected by Fermi over more than one year of observations for these sources, we investigate the effect of gamma-ray flux attenuation by the EBL. We place upper limits on the gamma-ray opacity of the Universe at various energies and redshifts, and compare this with predictions from well-known EBL models. We find that an EBL intensity in the optical-ultraviolet wavelengths as great as predicted by the "baseline" model of Stecker et al. (2006) can be ruled out with high confidence.Comment: 42 pages, 12 figures, accepted version (24 Aug.2010) for publication in ApJ; Contact authors: A. Bouvier, A. Chen, S. Raino, S. Razzaque, A. Reimer, L.C. Reye

CD14 is a coreceptor of Toll-like receptors 7 and 9

CD14 interacts with and is essential for the functions of endosomal TLR7 and TLR9 in mice

Heterogeneous Adaptive Trajectories of Small Populations on Complex Fitness Landscapes

Background Small populations are thought to be adaptively handicapped, not only because they suffer more from deleterious mutations but also because they have limited access to new beneficial mutations, particularly those conferring large benefits. Methodology/Principal Findings Here, we test this widely held conjecture using both simulations and experiments with small and large bacterial populations evolving in either a simple or a complex nutrient environment. Consistent with expectations, we find that small populations are adaptively constrained in the simple environment; however, in the complex environment small populations not only follow more heterogeneous adaptive trajectories, but can also attain higher fitness than the large populations. Large populations are constrained to near deterministic fixation of rare large-benefit mutations. While such determinism speeds adaptation on the smooth adaptive landscape represented by the simple environment, it can limit the ability of large populations from effectively exploring the underlying topography of rugged adaptive landscapes characterized by complex environments. Conclusions Our results show that adaptive constraints often faced by small populations can be circumvented during evolution on rugged adaptive landscapes

''Ikke sånn kjempeåpenbart, men forsiktig'' : seksuell kommunikasjon i uforpliktende forhold blant ungdom mellom 16 og 19 år

Mye av ungdommers seksuelle erfaringer skjer i dag utenfor en tradisjonell datingkontekst. På tross av dette har ungdommers seksuelle kommunikasjon sjelden vært fokus for forskning. Denne studien har undersøkt sending og tolkning av signaler mellom ungdommer på 16 og 19 år med fokus på en uforpliktende kontekst. Fokusgruppeintervjuer ble gjennomført med 15 jenter og 6 gutter fra en videregående skole i Trondheim. Ved hjelp av tematisk analyse og datadrevet koding kom studien frem til fire tema. Kjønnsrolleforventninger og skript omfatter utsagn eller signaler som antyder at man er forventet å handle på en spesifikk måte på bakgrunn av kjønn. Eskalerende signaler tar for seg utsagn om signaler som har til hensikt å eskalere eller heve intensiteten på seksuelle handlinger. Deregulerende signaler og avvisninger handler om hvordan en eller begge parter signaliserer et ønske om å senke tempo eller intensitet, alternativt å indikere at man ikke ønsker å fortsette. Signalers eksplisitthet og art omfatter hvilken grad av eksplisitthet kommunikasjonen legges på, altså hvor tydelig den er, og hvilken funksjon variasjoner i dette kan ha. Funnene viser at ungdommene har god forståelse for en rekke sofistikerte signaler, og utviser forsiktighet i møte med disse. Det ser også ut til at mye av kommunikasjonens art baserer seg på feilhåndtering og å unngå risiko forbundet med potensielle misforståelser

Morphological and physiological characterization of olfactory and multimodal neurons in the lateral horn of the Heliothinae moth

Through several hundred millions of years, evolution has developed and moulded the chemical senses in animals across our planet, echoing the ever changing environment. In a windy and turbulent field of flowers, insects that try to localize a single flower species embark on a challenging enterprise. Their brain and nervous system have developed key mechanisms to solve such problems. These mechanisms are seen conserved across species, not only limited to insects, but also in fishes and mammals, including humans. To understand how these mechanisms are realized, we must understand the morphological and physiological properties of the olfactory circuits. In this thesis, I have used intracellular recording and iontophoretic staining to investigate neurons in the lateral horn, a higher-order region of the insect brain. This was done in vivo, using two related Heliothinae moth species as a model organism. The injected fluorescent dye was visualized using confocal laser-scanning microscopy. I show both novel findings on the morphology of antennal-lobe projection neurons, and higher-order neurons innervating the lateral horn, as well as findings that complement previous work. Furthermore, this study shows that neurons in the lateral horn are most responsive to natural odour mixtures, like headspace sample from sunflower and the ideal pheromone mixture emitted by the female of the same species. In addition, I found that 19% of neurons in the lateral horn responding to antennal odourstimulation also respond to a light stimulus. Finally, a neuronal recording in one female of the species Helicoverpa armigera responded to single pheromone components and the ideal mixture, signifying the presence of pheromone autodetection in females of this species

Effects of heifers and sheep grazing on herbage production on a previously abandoned grassland

Large areas of cultivated grassland are annually abandoned and no longer used for production in Norway. Such areas will over time be encroached by shrubs and trees, which is regarded as undesirable. We assessed plant community development, pasture production, herbage quality and pasture utilization by sheep and heifers of a grassland that has been unmanaged for 12 years. e experiment was run for two consecutive years. Sheep grazed the whole area for one month in spring and autumn. During the summer, the area was assigned to three replicated treatments: (1) control with no management; (2) grazing heifers; and (3) grazing sheep with off€spring. Th e stocking rate was 1.8 LU ha-1, in both b and c, for a duration of one month. Th e area was left resting for a month a er treatment and before autumn sheep grazing. Pasture production and herbage intake was estimated using grazing exclosure cages. Herbage consumed during summer period was on average 211 g DM m-2 and the pasture utilization was 55%. The annual consumption and utilization was 336 g DM m-2 and 62% in the grazed treatments and 28 g DM m-2 and 15% in the control, respectively. Total annual pasture production was on average 72% higher in the grazed treatments compared to the control. T ere was no diff€erence between the grazed treatments on annual production, herbage intake or pasture utilization. Grazing stimulated herbage production, and such abandoned grasslands are valuable forage resources

Hippocampal growth hormone modulates relational memory and the dendritic spine density in CA1

Growth hormone (GH) deficiency is associated with cognitive decline which occur both in normal aging and in endocrine disorders. Several brain areas express receptors for GH although their functional role is unclear. To determine how GH affects the capacity for learning and memory by specific actions in one of the key areas, the hippocampus, we injected recombinant adeno-associated viruses (rAAVs) in male rats to express green fluorescent protein (GFP) combined with either GH, antagonizing GH (aGH), or no hormone, in the dorsal CA1. We found that aGH disrupted memory in the Morris water maze task, and that aGH treated animals needed more training to relearn a novel goal location. In a one-trial spontaneous location recognition test, the GH treated rats had better memory performance for object locations than the two other groups. Histological examinations revealed that GH increased the dendritic spine density on apical dendrites of CA1, while aGH reduced the spine density. GH increased the relative amount of immature spines, while aGH decreased the same amount. Our results imply that GH is a neuromodulator with strong influence over hippocampal plasticity and relational memory by mechanisms involving modulation of dendritic spines. The findings are significant to the increasing aging population and GH deficiency patients