bluuebunny/crossref_metadata_2025_split huggingface dataset:
Rosiglitazone Increases the Expression of Peroxisome Proliferator-Activated Receptor-γ Target Genes in Adipose Tissue, Liver, and Skeletal Muscle in the Sheep Fetus in Late Gestation
Authors: Muhlhausler B. S. , Morrison J. L. , McMillen I. C. 
Published: June 2009

Abstract
Exposure to maternal overnutrition increases the expression of peroxisome proliferator-activated receptor-γ (PPARγ) in adipose tissue before birth, and it has been proposed that the precocial activation of PPARγ target genes may lead to increased fat deposition in postnatal life. In this study, we determined the effect of intrafetal administration of a PPARγ agonist, rosiglitazone, on PPARγ target gene expression in fetal adipose tissue as well indirect actions of rosiglitazone on fetal liver and skeletal muscle. Osmotic pumps containing rosiglitazone (n = 7) or vehicle (15% ethanol, n = 7) were implanted into fetuses at 123–126 d gestation (term = 150 ± 3 d gestation). At 137–141 d gestation, tissues were collected and mRNA expression of PPARγ, lipoprotein lipase (LPL), adiponectin, and glycerol-3-phosphate dehydrogenase (G3PDH) in adipose tissue, PPARα and PPARγ-coactivator 1α (PGC1α) in liver and muscle and phosphoenolpyruvate carboxykinase (PEPCK) in liver determined by quantitative real-time RT-PCR. Plasma insulin concentrations were lower in rosiglitazone-treated fetuses (P &lt; 0.02). Rosiglitazone treatment resulted in increased expression of LPL and adiponectin mRNA (P &lt; 0.01) in fetal adipose tissue. The expression of PPARα mRNA in liver (P &lt; 0.05) and PGC1α mRNA (P &lt; 0.02) in skeletal muscle were also increased by rosiglitazone treatment. Rosiglitazone treatment increased expression of PPARγ target genes within fetal adipose tissue and also had direct or indirect actions on the fetal liver and muscle. The effects of activating PPARγ in fetal adipose tissue mimic those induced by prenatal overnutrition, and it is therefore possible that activation of PPARγ may be the initiating mechanism in the pathway from prenatal overnutrition to postnatal obesity.
Smelling the difference: controversial ideas in insect olfaction
Authors: Pellegrino Maurizio , Nakagawa Takao 
Published: June 2009

SUMMARY
In animals, the sense of smell is often used as a powerful way to attract potential mates, to find food and to explore the environment. Different animals evolved different systems to detect volatile odorants, tuned to the specific needs of each species. Vertebrates and nematodes have been used extensively as models to study the mechanisms of olfaction: the molecular players are olfactory receptors (ORs) expressed in olfactory sensory neurons(OSNs) where they bind to volatile chemicals, acting as the first relay of olfactory processing. These receptors belong to the G protein-coupled receptor(GPCR) superfamily; binding to odorants induces the production and amplification of second messengers, which lead to the depolarization of the neuron. The anatomical features of the insect olfactory circuit are similar to those of mammals, and until recently it was thought that this similarity extended to the ORs, which were originally annotated as GPCRs. Surprisingly,recent evidence shows that insect ORs can act like ligand-gated ion channels,either completely or partially bypassing the amplification steps connected to the activation of G proteins. Although the involvement of G proteins in insect olfactory signal transduction is still under question, this new discovery raises fascinating new questions regarding the function of the sense of smell in insects, its evolution and potential benefits compared with its mammalian counterpart.
Effects of corticosterone on innate and humoral immune functions and oxidative stress in barn owl nestlings
Authors: Stier Kim Silvana , Almasi Bettina , Gasparini Julien , Piault Romain , Roulin Alexandre , Jenni Lukas 
Published: June 2009

SUMMARYThe costs of coping with stressful situations are traded-off against other functions such as immune responses. This trade-off may explain why corticosterone secretion reduces immune reactions. Corticosterone differentially affects various immunity components. However, which component is suppressed varies between studies. It remains unclear whether the trade-off in energy, nutrition, autoimmunity or oxidative stress accounts for differential immunosuppression. In this study, we investigated whether corticosterone differentially affects the constitutive innate and humoral acquired immunity. We used barn owl nestlings, implanting 50% with a corticosterone-releasing pellet and the other 50% with a placebo pellet. To measure the effect on humoral immunity we vaccinated 50% of the corticosterone-nestlings and 50% of the placebo-nestlings with the antigens`Tetravac' and the other 50% were injected with PBS. To assess the costs of elevated corticosterone, we measured body mass and resistance to oxidative stress. Administration of corticosterone increased corticosterone levels whereas vaccination induced the production of antibodies. Corticosterone reduced the production of antibodies, but it did not significantly affect the constitutive innate immunity. Corticosterone reduced body growth and resistance to oxidative stress. Under stressful conditions barn owl nestlings seem to keep the constitutive innate immunity, whereas elevated corticosterone levels negatively affected inducible immune responses. We found evidence that mounting a humoral immune reaction is not costly in terms of growth, but reduces the resistance to oxidative stress independently of corticosterone administration. We suggest that humoral immunity is suppressed because the risk of immunopathologies may be disproportionately high when mounting an antibody response under stressful situations.
Temperature-induced elevation of basal metabolic rate does not affect testis growth in great tits
Authors: Caro Samuel P. , Visser Marcel E. 
Published: June 2009

SUMMARYThe timing of reproduction varies from year to year in many bird species. To adjust their timing to the prevailing conditions of that year, birds use cues from their environment. However, the relative importance of these cues,such as the initial predictive (e.g. photoperiod) and the supplemental factors(e.g. temperature), on the seasonal sexual development are difficult to distinguish. In particular, the fine-tuning effect of temperature on gonadal growth is not well known. One way temperature may affect timing is via its strong effect on energy expenditure as gonadal growth is an energy-demanding process. To study the interaction of photoperiod and temperature on gonadal development, we first exposed 35 individually housed male great tits (Parus major) to mid-long days (after 6 weeks of 8 h L:16 h D at 15°C, photoperiod was set to 13 h L:11 h D at 15°C). Two weeks later, for half of the males the temperature was set to 8°C, and for the other half to 22°C. Unilateral laparotomies were performed at weeks 5(i.e one week before the birds were transferred to mid-long days), 8 and 11 to measure testis size. Two measures of basal metabolic rate (BMR) were performed at the end of the experiment (weeks 11 and 12). Testis size increased significantly during the course of the experiment, but independently of the temperature treatment. BMR was significantly higher in birds exposed to the cold treatment. These results show that temperature-related elevation of BMR did not impair the long-day-induced testis growth in great tits. As a consequence, temperature may not be a crucial cue and/or constraint factor in the fine-tuning of the gonadal recrudescence in male great tits, and testis growth is not a high energy-demanding seasonal process.
Molecular identification of candidate chemoreceptor genes and signal transduction components in the sensory epithelium ofAplysia
Authors: Cummins S. F. , Leblanc L. , Degnan B. M. , Nagle G. T. 
Published: June 2009

SUMMARYAn ability to sense and respond to environmental cues is essential to the survival of most marine animals. How water-borne chemical cues are detected at the molecular level and processed by molluscs is currently unknown. In this study, we cloned two genes from the marine mollusk Aplysia dactylomela which encode multi-transmembrane proteins. We have performed in situ hybridization that reveals expression and spatial distribution within the long-distance chemosensory organs, the rhinophores. This finding suggests that they could be receptors involved in binding water-borne chemicals and coupling to an intracellular signal pathway. In support of this, we found expression of a phospholipase C and an inositol trisphosphate receptor in the rhinophore sensory epithelia and possibly distributed within outer dendrites of olfactory sensory neurons. In Aplysia, mate attraction and subsequent reproduction is initiated by responding to a cocktail of water-borne protein pheromones released by animal conspecifics. We show that the rhinophore contraction in response to pheromone stimulants is significantly altered following phospholipase C inhibition. Overall, these data provide insight into the molecular components of chemosensory detection in a mollusk. An important next step will be the elucidation of how these coordinate the detection of chemical cues present in the marine environment and activation of sensory neurons.
Agonistic behavior enhances adult neurogenesis in maleAcheta domesticuscrickets
Authors: Ghosal Kaushik , Gupta Mohit , Killian Kathleen A. 
Published: June 2009

SUMMARYWe examined the effect of agonistic behavior on cell proliferation and neurogenesis in the central nervous system (CNS) of adult male Acheta domesticus crickets. We combined 5-bromo,2′deoxyuridine(BrdU)-labeling of dividing cells with immunocytochemical detection of the neuronal marker horseradish peroxidase to examine the proliferation of progenitor cells and the survival of newborn neurons. In crickets, the mushroom bodies of the brain contain clusters of proliferative cells that divide and generate new neurons in adulthood. Pairs of male crickets were allowed to fight and establish social rank and were then injected with BrdU. Proliferation of mushroom body neurogenic cluster cells was unaffected by agonistic interactions; 24 h after a fight, the number of BrdU positive cells in fought and un-fought males did not significantly differ. However, agonistic interactions did influence cell survival. Two weeks after an agonistic interaction, fought males had more newborn neurons than males that did not fight. There was also a rank-specific effect because dominant males had significantly more new neurons than subordinates. We also report for the first time that neurogenesis in adult crickets can occur in other regions of the brain and in other CNS ganglia, including the terminal abdominal ganglion(TAG). Agonistic interactions enhanced the proliferation of these distributed precursor cells but did not increase the survival of the newborn neurons generated by these cells.
Enriching early adult environment affects the copulation behaviour of a tephritid fly
Authors: Díaz-Fleischer Francisco , Arredondo José , Aluja Martín 
Published: June 2009

SUMMARYEarly adult experiences in enriched environments favours animal brain and behavioural development ultimately resulting in an increased fitness. However,measuring the effect of environmental enrichment in animal behaviour in nature is often a complicated task, considering the complexity of the natural environment. We expanded previous studies to evaluate how early experience in an enriched environment affects copulation behaviour when animals are confronted with a complex semi-natural environment. Anastrepha ludensflies are an ideal model system for studying these effects because their natural habitats differ significantly from the cage environments in which these flies are reared for biological control purposes. For example, in the field, males form leks of up to six individuals. Each male defends a territory represented by a tree leaf whereas in rearing cages, territories are completely reduced because of the high population density. In a series of three experiments, we observed that male density represented the most influential stimulus for A. ludens male copulation success. Males that experienced lower densities in early adulthood obtained the highest proportion of copulations. By contrast, female copulation behaviour was not altered by female density. However, exposure to natural or artificial leaves in cages in which flies were kept until tested influenced female copulation behaviour. Females that were exposed to enriched environments exhibited a shorter latency to mate and shorter copulation durations with males than females reared in poor environments. We discuss the influence of early experience on male copulation success and female-mating choosiness.
Embryonic diapause highlighted by differential expression of mRNAs for ecdysteroidogenesis, transcription and lipid sparing in the cricketAllonemobius socius
Authors: Reynolds Julie A. , Hand Steven C. 
Published: June 2009

SUMMARYEmbryos of the ground cricket, Allonemobius socius, enter diapause 4–5 days post-oviposition and overwinter in this dormant state that is characterized by developmental arrest. Suppressive subtractive hybridization and quantitative real-time PCR reveal eight candidate genes in pre-diapause embryos that show promise as regulators of diapause entry, when compared with embryos not destined for diapause. Identifications are based both on the magnitude/consistency of differential mRNA abundances and the predicted functions of their products when placed in context of the physiological and biochemical events of diapause characterized in our companion paper. The proteins CYP450, AKR and RACK1 (associated with ecdysteroid synthesis and signaling) are consistently upregulated in pre-diapause, followed by major downregulation later in diapause. The pattern suggests that elevated ecdysone may facilitate onset of diapause in A. socius. Upregulation seen for the transcription factors Reptin and TFDp2 may serve to depress transcription and cell cycle progression. Cathpesin B-like protease, ACLY and MSP are three downregulated genes associated with yolk mobilization and/or metabolism that we predict may promote lipid sparing. Finally, embryos that have been in diapause for 10 days show a substantially different pattern of mRNA expression compared with either pre-diapause or embryos not destined for diapause, with the majority of mRNAs examined being downregulated. These transcript levels in later diapause suggest that a number of upregulated genes in pre-diapause are transiently expressed and are less essential as diapause progresses.
Zebra mussels anchor byssal threads faster and tighter than quagga mussels in flow
Authors: Peyer Suzanne M. , McCarthy Alice J. , Lee Carol Eunmi 
Published: June 2009

SUMMARY
While the invasive zebra mussel Dreissena polymorpha has rapidly spread throughout the Great Lakes and inland waterways, it is being displaced by the quagga mussel Dreissena bugensis in shallow water habitats. However, zebra mussels remain dominant in areas with higher water velocity. We hypothesized that the persistence of zebra over quagga mussels in habitats with higher water velocity might result from greater rate and strength of byssal thread attachment. We examined whether zebra mussels relative to quagga mussels have: (1) higher byssal thread synthesis rate, (2) lower dislodgment in flow and (3) greater mechanical force required for detachment from substrate. Specifically, we examined byssal thread synthesis rate and dislodgment of both species in response to water velocities of 0, 50, 100 and 180 cm s–1. Byssal thread synthesis rate was significantly higher for zebra than for quagga mussels at all velocities. Dislodgment from the substrate increased for both species with increasing velocity but was significantly lower for zebra than for quagga mussels. We also tested the mechanical force to detach mussels after short (32 h) and long (two and three months) periods of attachment on hard substrate. Detachment force was significantly higher for zebra than for quagga mussels only after short-term attachment. Higher byssal thread synthesis rate in zebra mussels was a likely factor that minimized their dislodgment in flow and increased short-term attachment strength. Differences in byssal thread synthesis rate between the two species might partly account for the ability of zebra mussels to maintain dominance over quagga mussels in habitats with high velocities.
Shape learning and discrimination in reef fish
Authors: Siebeck U. E. , Litherland L. , Wallis G. M. 
Published: June 2009

SUMMARY
Coral reef fish live in a complex world of colour and patterns. If they are to survive they need to be able to correctly identify the things they see(e.g. predators, prey) and act accordingly (e.g. flee, feed). This paper investigates whether discrimination is limited to ecologically relevant stimuli or is in fact more adaptable. Our work focuses on the reef damselfish Pomacentrus amboinensis. Within a day or two of capture the fish demonstrated an ability to associate an arbitrary stimulus with a food reward and to discriminate the reward stimulus from a distractor matched along various physical dimensions. In our initial experiments the reward was directly associated with the target. In the final experiment, however, the reward was separated from the target in both space and time, thereby eliminating a weakness applicable to the majority of food reward experiments involving fish; namely, the presence of olfactory cues emanating from the feeding tubes. All fish were not only able to solve this task but also showed anticipatory behaviour (also referred to as goal tracking). We conclude that freshly caught reef fish not only are able to quickly learn and discriminate between novel stimuli on the basis of shape but are also able to interpret stimuli as a predictor for the availability of food at a different time and place (anticipatory behaviour).
Four-choice sound localization abilities of two Florida manatees,Trichechus manatus latirostris
Authors: Colbert Debborah E. , Gaspard Joseph C. , Reep Roger , Mann David A. , Bauer Gordon B. 
Published: June 2009

SUMMARYThe absolute sound localization abilities of two Florida manatees(Trichechus manatus latirostris) were measured using a four-choice discrimination paradigm, with test locations positioned at 45 deg., 90 deg.,270 deg. and 315 deg. angles relative to subjects facing 0 deg. Three broadband signals were tested at four durations (200, 500, 1000, 3000 ms),including a stimulus that spanned a wide range of frequencies (0.2–20 kHz), one stimulus that was restricted to frequencies with wavelengths shorter than their interaural time distances (6–20 kHz) and one that was limited to those with wavelengths longer than their interaural time distances(0.2–2 kHz). Two 3000 ms tonal signals were tested, including a 4 kHz stimulus, which is the midpoint of the 2.5–5.9 kHz fundamental frequency range of manatee vocalizations and a 16 kHz stimulus, which is in the range of manatee best-hearing sensitivity. Percentage correct within the broadband conditions ranged from 79% to 93% for Subject 1 and from 51% to 93% for Subject 2. Both performed above chance with the tonal signals but had much lower accuracy than with broadband signals, with Subject 1 at 44% and 33% and Subject 2 at 49% and 32% at the 4 kHz and 16 kHz conditions, respectively. These results demonstrate that manatees are able to localize frequency bands with wavelengths that are both shorter and longer than their interaural time distances and suggest that they have the ability to localize both manatee vocalizations and recreational boat engine noises.
Rhabdom constriction enhances filtering by the red screening pigment in the eye of the Eastern Pale Clouded yellow butterfly, Colias erate(Pieridae)
Authors: Arikawa Kentaro , Pirih Primoz , Stavenga Doekele G. 
Published: June 2009

SUMMARY
Here we report the remarkable anatomy of the eye of the Eastern Pale Clouded yellow butterfly, Colias erate. An ommatidium of C. erate bears nine photoreceptors, R1–9, which together form a tiered and fused rhabdom. The distal tier of the rhabdom consists of the rhabdomeral microvilli of R1–4 photoreceptors, R5–8 photoreceptors contribute the proximal tier, and the R9 photoreceptor adds a few microvilli at the base. In transverse sections, four spots of red pigment surrounding the rhabdom are evident in the ventral region of the eye. The red pigment acts as a strong red filter for the proximal photoreceptors. The arrangement of the pigment spots distinguishes the ommatidia into three types: trapezoidal (type I), square(type II) and rectangular (type III). In all types of ommatidia, the distal and the proximal tiers of the rhabdom are divided by a strong constriction,clearly to enhance the filtering effect of the red pigment. The ommatidial heterogeneity can also be observed by optical measurements. The eye shine,resulting from tapetal reflections, peaks in type I ommatidia at 660 nm, and in type II and III ommatidia at 730 nm. The far-red-peaking eye shine indicates that C. erate has far-red-sensitive photoreceptors. Type I ommatidia fluoresce under violet excitation, implying the presence of a violet-absorbing pigment that acts as a short-wavelength filter.
Peripheral and behavioral plasticity of pheromone response and its hormonal control in a long-lived moth
Authors: Lemmen Joelle , Evenden Maya 
Published: June 2009

SUMMARY
Reproductive success in many animals depends on the efficient production of and response to sexual signals. In insects, plasticity in sexual communication is predicted in species that experience periods of reproductive inactivity when environmental conditions are unsuitable for reproduction. Here, we study a long-lived moth Caloptilia fraxinella (Ely) (Lepidoptera:Gracillariidae) that is reproductively inactive from eclosion in summer until the following spring. Male sex pheromone responsiveness is plastic and corresponds with female receptivity. Pheromone response plasticity has not been studied in a moth with an extended period of reproductive inactivity. In this study, we ask whether male antennal response and flight behavior are plastic during different stages of reproductive inactivity and whether these responses are regulated by juvenile hormone. Antennal response to the pheromone blend is significantly reduced in reproductively inactive males tested in the summer and autumn as compared with reproductively active males tested in the spring. Reproductively inactive autumn but not summer males show lower antennal responses to individual pheromone components compared with spring males. Treatment with methoprene enhances antennal response of autumn but not summer males to high doses of the pheromone blend. Behavioral response is induced by methoprene treatment in males treated in the autumn but not in the summer. Plasticity of pheromone response in C. fraxinella is regulated, at least in part, by the peripheral nervous system. Antennal and behavioral response to pheromone differed in reproductively active and inactive males and increased with methoprene treatment of inactive males.
Configuration of Adsorbed Phases and Their Evolution to Absorbent States in the CH4–O2 Catalytic Reaction
Authors: Cortés Joaquín , Valencia Eliana 
Published: June 2009

Abstract
Through kinetic Monte Carlo simulations of a catalytic reaction with a complex mechanism, such as the catalytic oxidation of methane, it is shown that the temporal evolution of the adsorbed phase to absorbent states is interpreted by an exponential decay of production. This semiempirical law, which has been used previously for systems with simple mechanisms, describes reactive and absorbent states and is in agreement with the results of the phase diagram. Substrates corresponding to square, hexagonal, and eight-coordination lattices are analyzed. In the first case it is shown that for most of the phase diagram the absorbent configuration of the adsorbed phase complies with the checkerboard structure found by Brosilow and Ziff in the case of a simple mechanism for the CO–NO reaction over a square lattice.