Millimeter-wave spectra of the Jovian planets

The millimeter wave portion of the electromagnetic spectrum is critical for understanding the subcloud atmospheric structure of the Jovian planets (Jupiter, Saturn, Uranus, and Neptune). This research utilizes a combination of laboratory measurements, computer modeling, and radio astronomical observation in order to obtain a better understanding of the millimeter-wave spectra of the Jovian planets. The pressure broadened absorption from gaseous ammonia (NH3) and hydrogen sulfide (H2S) was measured in the laboratory under simulated conditions for the Jovian atmospheres. Researchers developed new formalisms for computing the absorptivity of gaseous NH3 and H2S based on their laboratory measurements. They developed a radiative transfer and thermochemical model to predict the abundance and distribution of absorbing constituents in the Jovian atmospheres. They used the model to compute the millimeter wave emission from the Jovian planets

ADAR-mediated RNA editing suppresses sleep by acting as a brake on glutamatergic synaptic plasticity.

It has been postulated that synaptic potentiation during waking is offset by a homoeostatic reduction in net synaptic strength during sleep. However, molecular mechanisms to support such a process are lacking. Here we demonstrate that deficiencies in the RNA-editing gene Adar increase sleep due to synaptic dysfunction in glutamatergic neurons in Drosophila. Specifically, the vesicular glutamate transporter is upregulated, leading to over-activation of NMDA receptors, and the reserve pool of glutamatergic synaptic vesicles is selectively expanded in Adar mutants. Collectively these changes lead to sustained neurotransmitter release under conditions that would otherwise result in synaptic depression. We propose that a shift in the balance from synaptic depression towards synaptic potentiation in sleep-promoting neurons underlies the increased sleep pressure of Adar-deficient animals. Our findings provide a plausible molecular mechanism linking sleep and synaptic plasticity

Structural Analysis and Deletion Mutagenesis Define Regions of QUIVER/SLEEPLESS that Are Responsible for Interactions with Shaker-Type Potassium Channels and Nicotinic Acetylcholine Receptors.

Ly6 proteins are endogenous prototoxins found in most animals. They show striking structural and functional parallels to snake α-neurotoxins, including regulation of ion channels and cholinergic signaling. However, the structural contributions of Ly6 proteins to regulation of effector molecules is poorly understood. This question is particularly relevant to the Ly6 protein QUIVER/SLEEPLESS (QVR/SSS), which has previously been shown to suppress excitability and synaptic transmission by upregulating potassium (K) channels and downregulating nicotinic acetylcholine receptors (nAChRs) in wake-promoting neurons to facilitate sleep in Drosophila. Using deletion mutagenesis, co-immunoprecipitations, ion flux assays, surface labeling and confocal microscopy, we demonstrate that only loop 2 is required for many of the previously described properties of SSS in transfected cells, including interactions with K channels and nAChRs. Collectively our data suggest that QVR/SSS, and by extension perhaps other Ly6 proteins, target effector molecules using limited protein motifs. Mapping these motifs may be useful in rational design of drugs that mimic or suppress Ly6-effector interactions to modulate nervous system function

Activating Boxmind: an evaluation of a web‐based video lecture with synchronized activities

The aim of this study was to evaluate the use of synchronous computer‐mediated communication activities in a video e‐lecture. Previous research has reported that learning is facilitated when communication activities are added to a video lecture. Twelve postgraduate students participated in the study and they viewed a video e‐lecture on the perspective‐taking theory of communication. The lecture consisted of a video image of the lecturer, an audio track, slides, the transcript and a number of communication activities. They were given a pre‐test a week before the lecture and a post‐test a week after. They were also asked to rate the helpfulness of various aspects of the lecture. Students’ post‐test scores were statistically significantly higher than their pre‐test scores. They found the audio track, transcript, slides and activities helpful. The most helpful aspects were the communication activities. The implications of these findings are discussed

The opsonizing ligand on Salmonella typhimurium influences incorporation of specific, but not azurophil, granule constituents into neutrophil phagosomes.

Phagosomes were purified from human neutrophils ingesting Salmonella typhimurium opsonized with adsorbed normal human serum or with rabbit IgG. Constituents within the phagosome were endogenously labeled by supplying the cells with 125INa during phagocytosis. Lactoferrin and vitamin B12 binding protein (TC1 and TC3), markers for specific granules, were present in the phagosomes from neutrophils ingesting S. typhimurium opsonized with IgG but were 3.5- to 5-fold less prominent in phagosomes from cells phagocytosing Salmonella bearing C3 fragments only. In contrast, iodinated azurophilic granule components, most prominently defensins, were the major constituents in phagosomes prepared under both opsonization conditions. Furthermore, labeled complement (CR1 and CR3) and immunoglobulin (Fc gamma RIII) receptors were incorporated in the phagosome regardless of the ligand mediating phagocytosis. These results suggest that the ligand-receptor interactions mediating phagocytosis influence incorporation of neutrophil-specific granule contents into phagosomes

Regulation of Olfactory Stem Cells and Neurogenesis by Primary Cilia and the Hedgehog Pathway.

The olfactory epithelium (OE) is one of the few tissues to undergo constitutive neurogenesis throughout the mammalian lifespan. It contains multiple cell types including olfactory sensory neurons (OSNs) that are replaced by two populations of basal stem cells – frequently dividing globose basal cells (GBCs), and quiescent horizontal basal cells (HBCs). Strikingly, the mechanisms that control stem cell activation and proliferation, during normal OE homeostasis and in response to injury remain largely unexplored. My data indicate that HBCs possess primary cilia, cellular organelles that regulate the activity of multiple signaling pathways, including Hedgehog (HH) signaling. The HH pathway is required for the formation, survival, and activity of stem/progenitor cell populations in several adult tissues, making it an attractive candidate for HBC regulation. The goals of this dissertation are: 1) to investigate the role of primary cilia in HBC-driven olfactory neurogenesis and 2) to explore the contribution of HH signaling to HBC function. My data indicate that HBC-specific deletion of the ciliary gene Ift88 effectively abrogates primary cilia. Interestingly, the loss of HBC cilia did not affect HBC cell numbers or maintenance of the adult OE, but dramatically impaired the regeneration of OSNs following injury. Furthermore, the loss of cilia during development resulted in region-specific decreases in neurogenesis, implicating HBCs in in OE establishment. These results demonstrate a novel role for primary cilia in olfactory neurogenesis and suggest a role for primary cilia in HBC activation, proliferation, and differentiation. My data also demonstrate that HH pathway components are expressed in the adult OE. Specifically, the HH transcription factors, Gli2 and Gli3 are selectively expressed in HBCs, implicating HH signaling in the control of HBC function. Constitutive Gli2 activation in HBCs resulted in hyperproliferation and loss of neuronal cells, and also impaired OE regeneration following injury. Surprisingly, constitutive Gli2 repression in HBCs did not alter OE maintenance, but did impair injury-induced OE regeneration. These results suggest a novel role for HH signaling, and specifically Gli2, in HBC regulation during OE homeostasis and regeneration. Overall, this work defines novel roles for primary cilia and HH signaling in HBC-mediated regulation of the mammalian OE.PhDPharmacologyUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/120700/1/arieljoi_1.pd

Comparison of Microwear on Rodent Molars from Differing Species and a Wide Range of Environments

Dental microwear analysis is a very useful tool when trying to infer the diet of a particular organism. By studying the use-wear scars left on the enamel of the tooth due to eaten objects, one can infer the diet of the organism because certain types of food leave certain types of scars. For example, the consumption of tree parts produces pits, while the consumption of grasses produces striated scratches (Ungar et al., 2007). Thus, based on the type of microwear, the diet of the organism in question can be deduced, which indicates the type of environment that it lives in. In this study, rodents of three different species (Mastomys natalensis, Meriones libycus, and Praomys jacksoni) from differing environments were examined. Scale-sensitive fractal analysis was used to compare the microwear of these three species in order to determine if there were any differences in microwear, and if there were, the source of these differences were examined. This study showed that the central tendencies of the microwear did not differ significantly, but the variation in dispersion of microwear did