Antennal resolution of pulsed pheromone plumes in three moth species

Male antennae of Cadra cautella,Pectinophora gossypiella, and Spodoptera exigua were presented with 20-ms-duration pulses of their two-component pheromone at rates of 1 to 33 Hz. Fourier analyses of electroantennograms resolved the temporal structure of trains of pheromone filaments delivered at up to 33 Hz for C. cautella and S. exigua and 25 Hz for P. gossypiella. Pheromone components tested separately for each species were generally equivalent in filament resolution to complete blends. Ambient temperatures of 18, 23 and 28 °C affected filament resolution only slightly, with poorer ability to discriminate rapidly pulsed signals at 18 °C. The question of how, or indeed if, such frequencies are conserved beyond the peripheral nervous system, remains.     

Conserved surface-exposed K/R-X-K/R motifs and net positive charge on poxvirus complement control proteins serve as putative heparin binding sites and contribute to inhibition of molecular interactions with human endothelial cells: a novel mechanism for evasion of host defense

Vaccinia virus complement control protein (VCP) has been shown to possess the ability to inhibit both classical and alternative complement pathway activation. The newly found ability of this protein to bind to heparin has been shown in previous studies to result in uptake by mast cells, possibly promoting tissue persistence. It has also been shown to reduce chemotactic migration of leukocytes by blocking chemokine binding. In addition, this study shows that VCP-through its ability to bind to glycosaminoglycans (heparin-like molecules) on the surface of human endothelial cells-is able to block antibody binding to surface major histocompatibility complex class I molecules. Since heparin binding is critical for many functions of this protein, we have attempted to characterize the molecular basis for this interaction. Segments of this protein, generated by genetic engineering of the DNA encoding VCP into the Pichia pastoris expression system, were used to localize the regions with heparin binding activity. These regions were then analyzed to more specifically define their properties for binding. It was found that the number of putative binding sites (K/R-X-K/R), the overall positive charge, and the percentage of positively charged amino acids within the protein were responsible for this interaction.     

Flight of male Cadra cautella along plumes of air and pheromone superimposed on backgrounds of pheromone

Male Cadra cautella were presented with five heterogeneous pheromone clouds (created from source doses of 0, 0.01, 1, 100, and 10 000 ng) with and without superimposed plumes of either clean air or sex pheromone in a wind tunnel. Moths provided with the lowest doses of background clouds without a superimposed plume did not fly upwind. Moths provided with higher doses of background clouds, with or without superimposed air plumes, increased their track, course, and drift angles (i.e., their zigzags headed more towards crosswind) with increased dose, but slowed their velocity. No differences in flight track parameters were observed for moths provided with a superimposed pheromone plume, regardless of the background cloud dose. Moreover, moths were able to locate the source of superimposed air plumes in the highest background dose, and of superimposed pheromone plumes in any background dose. The significance of these results is discussed in the context of mating disruption.     

A Push-Pull CORF Model of a Simple Cell with Antiphase Inhibition Improves SNR and Contour Detection

We propose a computational model of a simple cell with push-pull inhibition, a property that is observed in many real simple cells. It is based on an existing model called Combination of Receptive Fields or CORF for brevity. A CORF model uses as afferent inputs the responses of model LGN cells with appropriately aligned center-surround receptive fields, and combines their output with a weighted geometric mean. The output of the proposed model simple cell with push-pull inhibition, which we call push-pull CORF, is computed as the response of a CORF model cell that is selective for a stimulus with preferred orientation and preferred contrast minus a fraction of the response of a CORF model cell that responds to the same stimulus but of opposite contrast. We demonstrate that the proposed push-pull CORF model improves signal-to-noise ratio (SNR) and achieves further properties that are observed in real simple cells, namely separability of spatial frequency and orientation as well as contrast-dependent changes in spatial frequency tuning. We also demonstrate the effectiveness of the proposed push-pull CORF model in contour detection, which is believed to be the primary biological role of simple cells. We use the RuG (40 images) and Berkeley (500 images) benchmark data sets of images with natural scenes and show that the proposed model outperforms, with very high statistical significance, the basic CORF model without inhibition, Gabor-based models with isotropic surround inhibition, and the Canny edge detector. The push-pull CORF model that we propose is a contribution to a better understanding of how visual information is processed in the brain as it provides the ability to reproduce a wider range of properties exhibited by real simple cells. As a result of push-pull inhibition a CORF model exhibits an improved SNR, which is the reason for a more effective contour detection.     

Direct behavioral evidence for retronasal olfaction in rats

The neuroscience of flavor perception is becoming increasingly important to understand abnormal feeding behaviors and associated chronic diseases such as obesity. Yet, flavor research has mainly depended on human subjects due to the lack of an animal model. A crucial step towards establishing an animal model of flavor research is to determine whether the animal uses the retronasal mode of olfaction, an essential element of flavor perception. We designed a go- no go behavioral task to test the rat's ability to detect and discriminate retronasal odorants. In this paradigm, tasteless aqueous solutions of odorants were licked by water-restricted head-fixed rats from a lick spout. Orthonasal contamination was avoided by employing a combination of a vacuum around the lick-spout and blowing clean air toward the nose. Flow models support the effectiveness of both approaches. The licked odorants were successfully discriminated by rats. Moreover, the tasteless odorant amyl acetate was reliably discriminated against pure distilled water in a concentration-dependent manner. The results from this retronasal odor discrimination task suggest that rats are capable of smelling retronasally. This direct behavioral evidence establishes the rat as a useful animal model for flavor research.     

Characterization of the SpaCBA pilus fibers in the probiotic Lactobacillus rhamnosus GG

Lactobacillus rhamnosus GG is a human intestinal isolate that has been studied intensively because of its probiotic properties. We have previously shown that L. rhamnosus GG produces proteinaceous pili that earlier had been observed only in Gram-positive pathogens (M. Kankainen et al., Proc. Natl. Acad. Sci. U. S. A. 106:17193-17198, 2009). These pili were found to be encoded by the spaCBA gene cluster, and the pilus-associated SpaC pilin was shown to confer on the cells a mucus-binding ability. In addition to the spaCBA cluster, another putative pilus cluster, spaFED, was predicted from the L. rhamnosus GG genome sequence. Herein, we show that only SpaCBA pili are produced by L. rhamnosus, and we describe a detailed analysis of cell wall-associated and affinity-purified SpaCBA pili by Western blotting and immunogold electron microscopy. Our results indicate that SpaCBA pili are heterotrimeric protrusions with a SpaA subunit as the shaft-forming major pilin. Only a few SpaB subunits could be observed in pilus fibers. Instead, SpaB pilins were found at pilus bases, as assessed by immunogold double labeling of thin sections of cells, suggesting that SpaB is involved in the termination of pilus assembly. The SpaC adhesin was present along the whole pilus length at numbers nearly equaling those of SpaA. The relative amount and uniform distribution of SpaC within pili not only makes it possible to exert both long-distance and intimate contact with host tissue but also provides mucus-binding strength, which explains the prolonged intestinal residency times observed for L. rhamnosus GG compared to that of nonpiliated lactobacilli.     

Interactive effects of global and regional change on a coastal ecosystem

Vertical distribution and diel vertical migration of a zooplankton community were studied at two stations off Central Peru in April 2006. Zooplankton was collected at five depth strata by vertical hauls with Hydo-Bios multinet (300-μm mesh, 0.25-m² mouth size). The zooplankton community was distributed in relation to a strong, shallow oxycline (1 ml l^?1 oxygen isopleth generally above 36 m). The highest total abundance was always in the upper, well-oxygenated layer. The most important species were: Acartia tonsa (72.86%), Centropages brachiatus (7.5%), and Paracalanus parvus (3.1%); Acartia tonsa was the dominant species at all times. Larvae of the polychaete Magelona sp. (7.5%) and larvae of the brachiopod Discinisca lamellosa (3.5%) were numerically dominant in April and small copepods e.g. Oncaea venusta (3.88%) were numerically dominant during August. Five distinct patterns of vertical distribution and migration in relation to the oxygen minimum layer were distinguished in this study: (1) Ontogenetic vertical migration through the oxycline (Acartia tonsa adults, nauplii, and copepodids), (2) permanent limitation to layers above the oxycline (e.g. Oikopleura sp., most invertebrate larvae), (3) distribution mostly below the oxycline with occasional migration into the layers just above the oxycline (Eucalanus inermis), (4) Diel Vertical Migration (Centropages brachiatus), and (5) reverse Diel Vertical Migration (larvae of the polychaete Magelona sp.).     

Effects of aging and arm swing on the metabolic cost of stability in human walking

To gain insight into the mechanical determinants of walking energetics, we investigated the effects of aging and arm swing on the metabolic cost of stabilization. We tested two hypotheses: (1) elderly adults consume more metabolic energy during walking than young adults because they consume more metabolic energy for lateral stabilization, and (2) arm swing reduces the metabolic cost of stabilization during walking in young and elderly adults. To test these hypotheses, we provided external lateral stabilization by applying bilateral forces (10% body weight) to a waist belt via elastic cords while young and elderly subjects walked at 1.3m/s on a motorized treadmill with arm swing and with no arm swing. We found that the external stabilizer reduced the net rate of metabolic energy consumption to a similar extent in elderly and young subjects. This reduction was greater (6-7%) when subjects walked with no arm swing than when they walked normally (3-4%). When young or elderly subjects eliminated arm swing while walking with no external stabilization, net metabolic power increased by 5-6%. We conclude that the greater metabolic cost of walking in elderly adults is not caused by a greater cost of lateral stabilization. Moreover, arm swing reduces the metabolic cost of walking in both young and elderly adults likely by contributing to stability.     

Exploring the multidimensionality of stature variation in the past through comparisons of archaeological and living populations

Adult stature variation is commonly attributed to differential stress-levels during development. However, due to selective mortality and heterogeneous frailty, a population's tall stature may be more indicative of high selective pressures than of positive life conditions. This article examines stature in a biocultural context and draws parallels between bioarchaeological and living populations to explore the multidimensionality of stature variation in the past. This study investigates: 1) stature differences between archaeological populations exposed to low or high stress (inferred from skeletal indicators); 2) similarities in growth retardation patterns between archaeological and living groups; and 3) the apportionment of variance in growth outcomes at the regional level in archaeological and living populations. Anatomical stature estimates were examined in relation to skeletal stress indicators (cribra orbitalia, porotic hyperostosis, linear enamel hypoplasia) in two medieval bioarchaeological populations. Stature and biocultural information were gathered for comparative living samples from South America. Results indicate 1) significant (P < 0.01) differences in stature between groups exposed to different levels of skeletal stress; 2) greater prevalence of stunting among living groups, with similar patterns in socially stratified archaeological and modern groups; and 3) a degree of regional variance in growth outcomes consistent with that observed for highly selected traits. The relationship between early stress and growth is confounded by several factors—including catch-up growth, cultural buffering, and social inequality. The interpretations of early life conditions based on the relationship between stress and stature should be advanced with caution. Am J Phys Anthropol 155:229–242, 2014. © 2014 Wiley Periodicals, Inc.     

Influenza A virus infection inhibits the efficient recruitment of Th2 cells into the airways and the development of airway eosinophilia

Most infections with respiratory viruses induce Th1 responses characterized by the generation of Th1 and CD8(+) T cells secreting IFN-gamma, which in turn have been shown to inhibit the development of Th2 cells. Therefore, it could be expected that respiratory viral infections mediate protection against asthma. However, the opposite seems to be true, because viral infections are often associated with the exacerbation of asthma. For this reason, we investigated what effect an influenza A (flu) virus infection has on the development of asthma. We found that flu infection 1, 3, 6, or 9 wk before allergen airway challenge resulted in a strong suppression of allergen-induced airway eosinophilia. This effect was associated with strongly reduced numbers of Th2 cells in the airways and was not observed in IFN-gamma- or IL-12 p35-deficient mice. Mice infected with flu virus and immunized with OVA showed decreased IL-5 and increased IFN-gamma, eotaxin/CC chemokine ligand (CCL)11, RANTES/CCL5, and monocyte chemoattractant protein-1/CCL2 levels in the bronchoalveolar lavage fluid, and increased airway hyperreactivity compared with OVA-immunized mice. These results suggest that the flu virus infection reduced airway eosinophilia by inducing Th1 responses, which lead to the inefficient recruitment of Th2 cells into the airways. However, OVA-specific IgE and IgG1 serum levels, blood eosinophilia, and goblet cell metaplasia in the lung were not reduced by the flu infection. Flu virus infection also directly induced AHR and goblet cell metaplasia. Taken together, our results show that flu virus infections can induce, exacerbate, and suppress features of asthmatic disease in mice.