Regulatory mechanisms in olfactory system assembly and function

The mammalian sense of smell relies on the detection of odorants by a large family of G protein coupled receptors, encoded by ~1300 different genes in mice (Buck and Axel, 1991; Zhang et al., 2007). These odorant receptors (ORs) are expressed in olfactory sensory neurons (OSNs) in the main olfactory epithelium (MOE). A key feature of the mammalian olfactory system is that each OSN expresses only one of 2600 potential OR alleles (Chess et al., 1994; Malnic et al., 1999) such that the expression of a single specific OR protein establishes the odorant selectivity and identity of an OSN. Several layers of regulation control odorant receptor choice (Nguyen et al., 2007). Understanding this regulatory hierarchy of OR gene expression is critical in elucidating how odorant receptor choice is orchestrated and how ORs pattern the system. Precise control of OR expression is fundamental for the assembly and operation of the MOE and the main olfactory bulb (MOB). ORs play an instructive role in OSN axon guidance and the generation of a topographic glomerular map in the MOB (Malnic et al., 1999; Ressler et al., 1994; Vassar et al., 1994; Mombaerts et al., 1996; Wang et al., 1998). This first order glomerular map resides on the surface of both olfactory bulbs and is mirror symmetric, i.e. each bulb is comprised of identical lateral and medial glomeruli (Ressler et al., 1994; Vassar et al., 1994; Mombaerts et al., 1996; Belluscio and Katz, 2001). These isofunctional glomeruli are precisely and reciprocally connected by a second order intrabulbar map directly beneath the surface glomerular map (Schoenfeld et al., 1985; Belluscio et al., 2002; Lodovichi et al., 2003). Neural activity plays an important role in establishing and shaping the connections within these olfactory maps and defines the functional organization of the system (Cummings and Belluscio, 2008). Olfactory maps likely result from a combination of neuronal activity and chemical guidance cues. While many families of guidance molecules have been found to be expressed in the olfactory system, their role in organization and function are not determined. GDNF and its receptor GFRα1 have been detected in the main olfactory system (Cao et al., 2006; Maroldt et al., 2005; Nosrat et al., 1997; Paratcha et al., 2006; Trupp et al., 1997), but their specific cellular localization and importance in the functional organization of the olfactory system is still unknown. Understanding the functional roles of GDNF signaling may provide a molecular basis for factors that pattern the olfactory system. This thesis investigates the mechanisms that regulate five fundamental components of olfactory system assembly and function: 1) odorant receptor expression, 2) odorant receptor choice, 3) OSN axon guidance, 4) olfactory maps, and 5) guidance molecules. Thematically specified, these mechanisms include the OR coding sequence in OR gene regulation, timing of OR expression, activity in the intrabulbar map, GDNF signaling in assembly and function, and GFRα1 in olfactory interneuron development

Alien Registration- Marks, Carolyn L. (Milo, Piscataquis County)

https://digitalmaine.com/alien_docs/8578/thumbnail.jp

Accuracy of Recollection Without Rehearsal

Priming refers to the influence of encountered objects on future responses to similar objects (Wang et. al., 2003). Cross-modality priming occurs when the stimuli are presented in one modality and tested within another (Marinis, 2018). However, there is not much research done on verbal and visual cross-modality priming. This study looks at the effects of cross-modality implicit priming on recall and recognition. Participants read 8 different priming stories. After each, participants completed a visual memory task where they looked at a slide of several images for 5 seconds, and then wrote which images they remembered. After this, they answered 2 questions about the story. This repeated for all 8 stories. After these tasks, participants completed a visual recognition task with 8 images that were primed and 8 novel images. They then completed a visual recognition task with 8 images that had been seen before but not primed, and 8 novel images. Lastly, they completed a visual recognition task with 8 images that related to the prime but had not been seen before, and 8 novel images. A within-subjects ANOVA was used for the primed images, and a within-subjects T test was used for the image recognition task. Results of this study are still being processed. These results provide more data for the effect of cross-modality priming, but more research needs to be done in this area

The Relationships Between Personality, Perceived Social Support, and Structure of Friend Groups

Friendship formation has been studied by many psychologists, focusing predominately on connectedness within the friendship and less focused on variation of characteristics within the group that influence group dynamic (Laakasu et. al., 2016). Personality traits are a large contributing factor when determining relationship satisfaction, specifically Neuroticism and Extraversion. Having high Neuroticism has shown to be a consistent predictor of low relationship quality (Finn, Mite, & Neyer, 2013). On the contrary, Extraversion’s positive affect (i.e. characterized as being cheerful, energetic, and social) is associated with better relationship outcomes (Lyubomirsky, King, & Deiner, 2005). Undergraduate students (N = 50) completed a survey containing a personality assessment, perceived social support questionnaire, friendship structure questionnaire, and demographics on Qualtrics. We anticipate participants who score higher on neuroticism will report less perceived social support and feeling less at the center of the friend group. Participants who score higher on extraversion will perceive social support positively and will report feeling at the center of the friend group. Assessing the perceived social support and structure of a friend group from an individual allows us to better understand that individual’s associated personality traits

Actin- and myosin-driven movement of viruses along filopodia precedes their entry into cells

Viruses have often been observed in association with the dense microvilli of polarized epithelia as well as the filopodia of nonpolarized cells, yet whether interactions with these structures contribute to infection has remained unknown. Here we show that virus binding to filopodia induces a rapid and highly ordered lateral movement, “surfing” toward the cell body before cell entry. Virus cell surfing along filopodia is mediated by the underlying actin cytoskeleton and depends on functional myosin II. Any disruption of virus cell surfing significantly reduces viral infection. Our results reveal another example of viruses hijacking host machineries for efficient infection by using the inherent ability of filopodia to transport ligands to the cell body

Ultrafast manipulation of mirror domain walls in a charge density wave

Domain walls (DWs) are singularities in an ordered medium that often host exotic phenomena such as charge ordering, insulator-metal transition, or superconductivity. The ability to locally write and erase DWs is highly desirable, as it allows one to design material functionality by patterning DWs in specific configurations. We demonstrate such capability at room temperature in a charge density wave (CDW), a macroscopic condensate of electrons and phonons, in ultrathin 1T-TaS$_2$. A single femtosecond light pulse is shown to locally inject or remove mirror DWs in the CDW condensate, with probabilities tunable by pulse energy and temperature. Using time-resolved electron diffraction, we are able to simultaneously track anti-synchronized CDW amplitude oscillations from both the lattice and the condensate, where photo-injected DWs lead to a red-shifted frequency. Our demonstration of reversible DW manipulation may pave new ways for engineering correlated material systems with light