Behavioral Measurement of Sensation Seeking Shows Positive Association with Risky Behaviors

poster abstractSensation seeking (SS; the tendency to seek out experiences that are highly varied, novel, and intense, and the willingness to take risks in order to have such experiences) is strongly related to risky behavior. However, most prior research has relied on self-report assessments of SS, which are limited by subject biases and lack of insight. This study is designed to develop and optimize a behavioral assessment of SS to be used in future brain imaging studies, and to evaluate the relationship of this behavior with selfreported SS and risky behaviors. The novel behavioral SS task employed in this study presents participants with olfactory sensory stimuli and assesses the individual’s preference to seek varied, novel, and intense sensations, with the risk of an unpleasant stimulus (“Varied”; e.g. strong orange, rose, linalyl acetate, and propionic acid) vs. weaker and mildly pleasant sensations (“Standard”; weak vanillin, orange, and rose) across two twenty-trial sessions. Hypothesis: greater preference for “Varied” odors will correlate with self-reported SS and risky behaviors. Odorants are presented as a 1-sec burst via an airdilution olfactometer within a filtered airstream. Participants are being recruited from the Introduction to Psychology class at IUPUI (currently n = 11 total, mean age (SD) = 21.2, (5.4), n = 8 women, n = 7 Caucasian). The mean preference for “Varied” was 50%, range = 28-75%. Preference for “Varied” showed a moderate relationship with negative risky behaviors (r = 0.35) and SS (Zuckerman Thrill/Adventure seeking subscale; r = 0.48), suggesting that the behavioral task is associating as expected with these self-report variables. These preliminary data suggests the feasibility of behavioral SS assessment; behavioral characterization will permit examination of how SS influences brain activity, without the limitations of self-report. How SS affects choice of and reactions to new and exciting experiences has important research and clinical implications

Quantifying Behavioral Sensation Seeking With the Aroma Choice Task

Our goal was to develop a behavioral measure of sensation seeking (SS). The Aroma Choice Task (ACT) assesses preference for an intense, novel, varied, and risky (exciting) option versus a mild, safe (boring) option using real-time odorant delivery. A total of 147 healthy young adults completed 40 binary choice trials. We examined (1) intensity and pleasantness of odorants, (2) stability of responding, (3) association with SS self-report, and (4) association with self-reported illicit drug use. Participants’ preference for the “exciting” option versus the safe option was significantly associated with self-reported SS (p < .001) and illicit drug use (p = .041). Odorant ratings comported with their intended intensity. The ACT showed good internal, convergent, and criterion validity. We propose that the ACT might permit more objective SS assessment for investigating the biological bases of psychiatric conditions marked by high SS, particularly addiction. The ACT measures SS behaviorally, mitigating some self-report challenges and enabling real-time assessment, for example, for functional magnetic resonance imaging (fMRI)

A rapid and sensitive assay for quantification of siRNA efficiency and specificity

RNA Interference has rapidly emerged as an efficient procedure for knocking down gene expression in model systems. However, cross-reactivity, whereby multiple genes may be simultaneously targeted by a single short interfering RNA (siRNA), can potentially jeopardize correct interpretation of gene function. As such, it is essential to test the specificity of a siRNA prior to a full phenotypic analysis. To this end, we have adapted a reporter-based assay harnessing the sensitivity of luciferase activity to provide a quantitative readout of relative RNAi efficacy and specificity. We have tested different siRNAs directed against Thymosin β4 (Tβ4); determined their effectiveness at silencing Tβ4 and have both excluded off-target silencing of the Tβ4 homologue Thymosin β10 (Tβ10) and demonstrated partial knockdown of Tβ10 despite significant (12/23; 52%) sequence mismatch. This assay system is applicable to any RNAi study where there is a risk of targeting homologous genes and to the monitoring of off-target effects at the genome level following microarray expression profiling

Regulatory elements and transcriptional control of chicken vasa homologue (CVH) promoter in chicken primordial germ cells

BACKGROUND: Primordial germ cells (PGCs), the precursors of functional gametes, have distinct characteristics and exhibit several unique molecular mechanisms to maintain pluripotency and germness in comparison to somatic cells. They express germ cell-specific RNA binding proteins (RBPs) by modulating tissue-specific cis- and trans-regulatory elements. Studies on gene structures of chicken vasa homologue (CVH), a chicken RNA binding protein, involved in temporal and spatial regulation are thus important not only for understanding the molecular mechanisms that regulate germ cell fate, but also for practical applications of primordial germ cells. However, very limited studies are available on regulatory elements that control germ cell-specific expression in chicken. Therefore, we investigated the intricate regulatory mechanism(s) that governs transcriptional control of CVH. RESULTS: We constructed green fluorescence protein (GFP) or luciferase reporter vectors containing the various 5′ flanking regions of CVH gene. From the 5′ deletion and fragmented assays in chicken PGCs, we have identified a CVH promoter that locates at −316 to +275 base pair fragment with the highest luciferase activity. Additionally, we confirmed for the first time that the 5′ untranslated region (UTR) containing intron 1 is required for promoter activity of the CVH gene in chicken PGCs. Furthermore, using a transcription factor binding prediction, transcriptome analysis and siRNA-mediated knockdown, we have identified that a set of transcription factors play a role in the PGC-specific CVH gene expression. CONCLUSIONS: These results demonstrate that cis-elements and transcription factors localizing in the 5′ flanking region including the 5′ UTR and an intron are important for transcriptional regulation of the CVH gene in chicken PGCs. Finally, this information will contribute to research studies in areas of reproductive biology, constructing of germ cell-specific synthetic promoter for tracing primordial germ cells as well as understanding the transcriptional regulation for maintaining germness in PGCs

Efficient Construction of an Inverted Minimal H1 Promoter Driven siRNA Expression Cassette: Facilitation of Promoter and siRNA Sequence Exchange

RNA interference (RNAi), mediated by small interfering RNA (siRNA), is an effective method used to silence gene expression at the post-transcriptional level. Upon introduction into target cells, siRNAs incorporate into the RNA-induced silencing complex (RISC). The antisense strand of the siRNA duplex then "guides" the RISC to the homologous mRNA, leading to target degradation and gene silencing. In recent years, various vector-based siRNA expression systems have been developed which utilize opposing polymerase III promoters to independently drive expression of the sense and antisense strands of the siRNA duplex from the same template.We show here the use of a ligase chain reaction (LCR) to develop a new vector system called pInv-H1 in which a DNA sequence encoding a specific siRNA is placed between two inverted minimal human H1 promoters (approximately 100 bp each). Expression of functional siRNAs from this construct has led to efficient silencing of both reporter and endogenous genes. Furthermore, the inverted H1 promoter-siRNA expression cassette was used to generate a retrovirus vector capable of transducing and silencing expression of the targeted protein by>80% in target cells.The unique design of this construct allows for the efficient exchange of siRNA sequences by the directional cloning of short oligonucleotides via asymmetric restriction sites. This provides a convenient way to test the functionality of different siRNA sequences. Delivery of the siRNA cassette by retroviral transduction suggests that a single copy of the siRNA expression cassette efficiently knocks down gene expression at the protein level. We note that this vector system can potentially be used to generate a random siRNA library. The flexibility of the ligase chain reaction suggests that additional control elements can easily be introduced into this siRNA expression cassette

Light in the Polar Night

How much light isa vailable for biological processes during Polar Night? This question appears simple enough. But the reality is that conventional light sen- sors for measuring visible light (~350 to ~700 nm) have not been sensitive enough to answer it. Beyond this technical challenge, “light” is a general term that must be qualified in terms of “light climate” before it has meaning for biological systems. In this chapter, we provide an answer to the question posed above and explore aspects of light climate during Polar Night with relevance to biology, specifically, how Polar Night is defined by solar elevation, atmospheric light in Polar Night and its propaga- tion underwater, bioluminescence in Polar Night and the concept of Polar Night as a deep-sea analogue, light pollution, and future perspectives. This chapter focuses on the quantity and quality of light present during Polar Night, while subsequent chapters in this volume focus on specific biological effects of this light for algae (Chap. “Marine Micro- and Macroalgae in the Polar Night”), zooplankton (Chaps.“Zooplankton in the Polar Night” and “Biological Clocks and Rhythms in Polar Organisms”), and fish (Chap. “Fish Ecology in the Polar Night”)

A SELEX-Screened Aptamer of Human Hepatitis B Virus RNA Encapsidation Signal Suppresses Viral Replication

Background: The specific interaction between hepatitis B virus (HBV) polymerase (P protein) and the e RNA stem-loop on pregenomic (pg) RNA is crucial for viral replication. It triggers both pgRNA packaging and reverse transcription and thus represents an attractive antiviral target. RNA decoys mimicking e in P protein binding but not supporting replication might represent novel HBV inhibitors. However, because generation of recombinant enzymatically active HBV polymerase is notoriously difficult, such decoys have as yet not been identified. Methodology/Principal Findings: Here we used a SELEX approach, based on a new in vitro reconstitution system exploiting a recombinant truncated HBV P protein (miniP), to identify potential e decoys in two large e RNA pools with randomized upper stem. Selection of strongly P protein binding RNAs correlated with an unexpected strong enrichment of A residues. Two aptamers, S6 and S9, displayed particularly high affinity and specificity for miniP in vitro, yet did not support viral replication when part of a complete HBV genome. Introducing S9 RNA into transiently HBV producing HepG2 cells strongly suppressed pgRNA packaging and DNA synthesis, indicating the S9 RNA can indeed act as an e decoy that competitively inhibits P protein binding to the authentic e signal on pgRNA. Conclusions/Significance: This study demonstrates the first successful identification of human HBV e aptamers by an in vitro SELEX approach. Effective suppression of HBV replication by the S9 aptamer provides proof-of-principle for the abilit

An unusually compact external promoter for RNA polymerase III transcription of the human H1RNA gene

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