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Search Results: 1 - 10 of 403030 matches for " Leslie M Stone "
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Evidence for a role of glutamate as an efferent transmitter in taste buds
Aurelie Vandenbeuch, Marco Tizzano, Catherine B Anderson, Leslie M Stone, Daniel Goldberg, Sue C Kinnamon
BMC Neuroscience , 2010, DOI: 10.1186/1471-2202-11-77
Abstract: Using molecular and immunohistochemical techniques, we show that the vesicular transporters for glutamate, VGLUT 1 and 2, but not VGLUT3, are expressed in the nerve fibers surrounding taste buds but likely not in taste cells themselves. Further, we show that P2X2, a specific marker for gustatory but not trigeminal fibers, co-localizes with VGLUT2, suggesting the VGLUT-expressing nerve fibers are of gustatory origin. Calcium imaging indicates that GAD67-GFP Type III taste cells, but not T1R3-GFP Type II cells, respond to glutamate at concentrations expected for a glutamate transmitter, and further, that these responses are partially blocked by NBQX, a specific AMPA/Kainate receptor antagonist. RT-PCR and immunohistochemistry confirm the presence of the Kainate receptor GluR7 in Type III taste cells, suggesting it may be a target of glutamate released from gustatory nerve fibers.Taken together, the results suggest that glutamate may be released from gustatory nerve fibers using a vesicular mechanism to modulate Type III taste cells via GluR7.L-glutamate (hereafter referred to as glutamate) has been proposed to play a role in neurotransmission in the peripheral taste system [1,2]. Evidence supporting a role for glutamate as a transmitter includes the expression of glutamate receptors in taste cells [3-8] as well as the presence of the glutamate transporter GLAST [9]. However, the origin of glutamate and its sites of action in the taste bud are not well understood. For example, glutamate could be released from taste cells to activate glutamate receptors on adjacent taste cells or afferent nerve fibers. Alternatively, glutamate could be released from either gustatory or somatosensory nerve fibers to modulate the activity of taste cells. Studies examining the function of glutamate as a transmitter in the taste system are complicated by the fact that glutamate is also a taste stimulus that elicits the umami taste (for review, [10-12]. However, gustatory nerve responses to
Immunocytochemical evidence for co-expression of Type III IP3 receptor with signaling components of bitter taste transduction
Tod R Clapp, Leslie M Stone, Robert F Margolskee, Sue C Kinnamon
BMC Neuroscience , 2001, DOI: 10.1186/1471-2202-2-6
Abstract: Antibodies against Type I, II, and III IP3 receptors were tested on sections of rat and mouse circumvallate papillae. Robust cytoplasmic labeling for the Type III IP3 receptor (IP3R3) was found in a large subset of taste cells in both species. In contrast, little or no immunoreactivity was seen with antibodies against the Type I or Type II IP3 receptors. To investigate the potential role of IP3R3 in bitter taste transduction, we used double-label immunocytochemistry to determine whether IP3R3 is expressed in the same subset of cells expressing other bitter signaling components. IP3R3 immunoreactive taste cells were also immunoreactive for PLCβ2 and γ13. Alpha-gustducin immunoreactivity was present in a subset of IP3R3, PLCβ2, and γ13 positive cells.IP3R3 is the dominant form of the IP3 receptor expressed in taste cells and our data suggest it plays an important role in bitter taste transduction.Taste receptor cells are specialized epithelial cells, which are organized into discrete endorgans called taste buds. Typical taste buds contain 50-100 polarized taste cells, which extend from the basal lamina to the taste pore, where apical microvilli protrude into the oral cavity. The basolateral membrane forms chemical synapses with primary gustatory neurons (Fig. 1A). In mammals, lingual taste buds are housed in connective tissue structures called papillae. Fungiform papillae are located on the anterior two-thirds of the tongue and typically contain 1-2 taste buds each. Vallate and foliate papillae are found on the posterior tongue and house several hundred taste buds each. Taste transduction begins when sapid stimuli interact with the apical membrane of taste cells, usually resulting in taste cell depolarization, calcium influx, and transmitter release onto gustatory afferent neurons. Simple stimuli, such as salts and acids depolarize taste cells by direct interaction with apical ion channels. In contrast, complex stimuli, such as sugars, amino acids, and most bitter com
An Overlooked Term in Assessment of the Potential Sea-Level Rise from a Collapse of the West Antarctic Ice Sheet  [PDF]
Diandong Ren, Mervyn Lynch, Lance M. Leslie
International Journal of Geosciences (IJG) , 2013, DOI: 10.4236/ijg.2013.46090
Abstract:

As to sea level rise (SLR) contribution, melting and setting afloat make no difference for land based ice. Melting of West Antarctic Ice Sheet (WAIS) into water is impossible in the upcoming several centuries, whereas breaking and partially afloat is likely as long as sea waters find a pathway to the bottom of those ice sectors with basal elevation below sea level. In this sense WAIS may be disintegrated in a future warming climate. We reassess the potential contribution to eustatic sea level from a collapse of WAIS and find that previous assessments have overlooked a contributor: slope instability after the cementing ice is removed. Over loading ice has a buttressing effect on slope movements the same way ice shelves hinder the flow of non-floating coastal ice. A sophisticated landslide model estimates a 9-mm eustatic SLR contribution from subsequent landslides.

Impact of the Glucosinolate Sinigrin on Bacterial Communities in Pieris rapae  [PDF]
Leslie M. McKinnon, Courtney J. Robinson
Advances in Microbiology (AiM) , 2016, DOI: 10.4236/aim.2016.68057
Abstract: Dynamics in animal-associated microbiota can be difficult to study due to community complexity. Previous work showed that microbial communities in the midguts of Pieris rapae larvae contain relatively few members. In this study, we used P. rapae to test hypotheses related to how diet impacts gastrointestinal microbiota. More specifically, we investigated how the concentration of sinigrin, a glucosinolate in the natural diet of this insect, alters microbial community structure. Larvae were fed either sterile wheat germ diet alone or amended with 3.0 mg/ml, 6.0 mg/ml, or 9.0 mg/ml of sinigrin. In order to determine shifts in the gut microbial community, 16S rRNA genes from midguts were subjected to pyrosequencing and analyzed. Sinigrin had a significant impact on microbial communities in fourth instar P. rapae larvae, but this was dependent on concentration. The predominant phyla in all treatment groups were Proteobacteria and Firmicutes. Significant difference in beta diversity was typically observed when sinigrin 6 mg/ml and the control treatment groups were compared. The impact of sinigrin on the structure of the midgut microbiota is dependent on concentration, but not in a linear fashion. This may indicate that types and concentrations of glucosinolates have varied impact on midgut microbial community.
第三代数据库系统宣言
Stone.,M 杜小勇
计算机科学 , 1991,
Abstract: 我们将早期的层次和网状数据库系统称做第一代数据库系统,现在的这些关系系统称做第二代数据库系统。本文将讨论我们称做第三代数据库系统的下一代数据管理系统所应具有的特征。文中提出的3条基本原则和13个详述的命题集中反映了我们的要求。
Transient Population Dynamics of Mosquitoes during Sterile Male Releases: Modelling Mating Behaviour and Perturbations of Life History Parameters
Christopher M. Stone
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0076228
Abstract: The release of genetically-modified or sterile male mosquitoes offers a promising form of mosquito-transmitted pathogen control, but the insights derived from our understanding of male mosquito behaviour have not fully been incorporated into the design of such genetic control or sterile-male release methods. The importance of aspects of male life history and mating behaviour for sterile-male release programmes were investigated by projecting a stage-structured matrix model over time. An elasticity analysis of transient dynamics during sterile-male releases was performed to provide insight on which vector control methods are likely to be most synergistic. The results suggest that high mating competitiveness and mortality costs of released males are required before the sterile-release method becomes ineffective. Additionally, if released males suffer a mortality cost, older males should be released due to their increased mating capacity. If released males are of a homogenous size and size-assortative mating occurs in nature, this can lead to an increase in the abundance of large females and reduce the efficacy of the population-suppression effort. At a high level of size-assortative mating, the disease transmission potential of the vector population increases due to male releases, arguing for the release of a heterogeneously-sized male population. The female population was most sensitive to perturbations of density-dependent components of larval mortality and female survivorship and fecundity. These findings suggest source reduction might be a particularly effective complement to mosquito control based on the sterile insect technique (SIT). In order for SIT to realize its potential as a key component of an integrated vector-management strategy to control mosquito-transmitted pathogens, programme design of sterile-male release programmes must account for the ecology, behaviour and life history of mosquitoes. The model used here takes a step in this direction and can easily be modified to investigate additional aspects of mosquito behaviour or species-specific ecology.
The Wardle Instability in Interstellar Shocks: I. Nonlinear Dynamical Evolution
James M. Stone
Physics , 1997, DOI: 10.1086/304595
Abstract: The nonlinear evolution of unstable C-type shocks in weakly ionized plasmas is studied by means of time-dependent magnetohydrodynamical simulations. This study is limited to shocks in magnetically dominated plasmas (in which the Alfven speed in the neutrals greatly exceeds the sound speed), and microphysical processes such as ionization and recombination are not followed. Both two-dimensional simulations of planar perpendicular and oblique C-type shocks, and fully three-dimensional simulation of a perpendicular shock are presented.
Dynamics on the Edge: Star-Disk Interaction
James M. Stone
Physics , 1998, DOI: 10.1063/1.55943
Abstract: Our understanding of the dynamical processes which control the structure and evolution of the interaction region between an accretion disk and the central star is reviewed. If the central star is unmagnetized, this interaction is in the form of a classical boundary layer. However, if the central star is strongly magnetized, it is expected that the inner disk is truncated by the stellar field, and the accretion flow follows the stellar field lines to the magnetic poles. Several outstanding questions remain regarding this picture. It is likely that numerical MHD simulations will prove essential to answering these questions. However, in order to model the MHD turbulence, angular momentum transport, and possible dynamo action associated with the dynamics of star-disk interaction, fully three-dimensional simulations spanning long dynamical times are required.
FLECS: Planning with a Flexible Commitment Strategy
M. Veloso,P. Stone
Computer Science , 1995,
Abstract: There has been evidence that least-commitment planners can efficiently handle planning problems that involve difficult goal interactions. This evidence has led to the common belief that delayed-commitment is the "best" possible planning strategy. However, we recently found evidence that eager-commitment planners can handle a variety of planning problems more efficiently, in particular those with difficult operator choices. Resigned to the futility of trying to find a universally successful planning strategy, we devised a planner that can be used to study which domains and problems are best for which planning strategies. In this article we introduce this new planning algorithm, FLECS, which uses a FLExible Commitment Strategy with respect to plan-step orderings. It is able to use any strategy from delayed-commitment to eager-commitment. The combination of delayed and eager operator-ordering commitments allows FLECS to take advantage of the benefits of explicitly using a simulated execution state and reasoning about planning constraints. FLECS can vary its commitment strategy across different problems and domains, and also during the course of a single planning problem. FLECS represents a novel contribution to planning in that it explicitly provides the choice of which commitment strategy to use while planning. FLECS provides a framework to investigate the mapping from planning domains and problems to efficient planning strategies.
第三代数据库系统宣言
Stone.,M 杜小勇?
计算机科学 , 1991,
Abstract:
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