Humans have ~400 intact odorant receptors, but each individual has a unique set of genetic variations that lead to variation in olfactory perception. We used a heterologous assay to determine how ...often genetic polymorphisms in odorant receptors alter receptor function. We identified agonists for 18 odorant receptors and found that 63% of the odorant receptors we examined had polymorphisms that altered in vitro function. On average, two individuals have functional differences at over 30% of their odorant receptor alleles. To show that these in vitro results are relevant to olfactory perception, we verified that variations in OR10G4 genotype explain over 15% of the observed variation in perceived intensity and over 10% of the observed variation in perceived valence for the high-affinity in vitro agonist guaiacol but do not explain phenotype variation for the lower-affinity agonists vanillin and ethyl vanillin.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
Transport features predict if a molecule is odorous Mayhew, Emily J; Arayata, Charles J; Gerkin, Richard C ...
Proceedings of the National Academy of Sciences - PNAS,
04/2022, Letnik:
119, Številka:
15
Journal Article
Recenzirano
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In studies of vision and audition, stimuli can be chosen to span the visible or audible spectrum; in olfaction, the axes and boundaries defining the analogous odorous space are unknown. As a result, ...the population of olfactory space is likewise unknown, and anecdotal estimates of 10,000 odorants have endured. The journey a molecule must take to reach olfactory receptors (ORs) and produce an odor percept suggests some chemical criteria for odorants: a molecule must 1) be volatile enough to enter the air phase, 2) be nonvolatile and hydrophilic enough to sorb into the mucous layer coating the olfactory epithelium, 3) be hydrophobic enough to enter an OR binding pocket, and 4) activate at least one OR. Here, we develop a simple and interpretable quantitative model that reliably predicts whether a molecule is odorous or odorless based solely on the first three criteria. Applying our model to a database of all possible small organic molecules, we estimate that at least 40 billion possible compounds are odorous, six orders of magnitude larger than current estimates of 10,000. With this model in hand, we can define the boundaries of olfactory space in terms of molecular volatility and hydrophobicity, enabling representative sampling of olfactory stimulus space.
Genomic characterization of an Escherichia coli O157:H7 strain linked to leafy greens–associated outbreaks dates its emergence to late 2015. One clade has notable accessory genomic content and a ...previously described mutation putatively associated with increased arsenic tolerance. This strain is a reoccurring, emerging, or persistent strain causing illness over an extended period.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, ODKLJ, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Individuals living with sickle cell disease experience high levels of morbidity that result in frequent utilization of the emergency department. The objective of this study was to provide updated ...national estimates of emergency department utilization associated with sickle cell disease in the U.S.
Data from the National Hospital Ambulatory Medical Care Survey for the years 1999-2020 were analyzed. Complex survey analysis was utilized to produce national estimates overall and by patient age groups.
On average, approximately 222,612 emergency department visits occurred annually among individuals with sickle cell disease, a nearly 13% increase from prior estimates. The annual volume of emergency department visits steadily increased over time, and pain remains the most common patient-cited reason for visiting the emergency department. Patient-reported pain levels for individuals with sickle cell disease were high, with 64% of visits associated with severe pain and 21% associated with moderate pain. Public insurance sources continue to cover most visits, with Medicaid paying for 60% of visits and Medicare paying for 12% of visits. The average time spent in the emergency department increased from previous estimates by about an hour, rising to approximately 6 hours. The average wait time to see a provider was 53 minutes.
Utilization of the emergency department by individuals living with sickle cell disease remains high, especially for pain. With more than half of patients with sickle cell disease reporting severe pain levels, emergency department staff should be prepared to assess and treat sickle cell disease-related pain following evidence-based guidelines and recommendations. The findings of this study can help improve care in this population.
Abstract Clinical research activities at academic medical centers are challenging to oversee. Without effective research administration, a continually evolving set of regulatory and institutional ...requirements can divert investigator and study team attention away from a focus on scientific gain, study conduct, and patient safety. However, even when the need for research administration is recognized, there can be struggles over what form it should take. Central research administration may be viewed negatively, with individual groups preferring to maintain autonomy over processes. Conversely, a proliferation of individualized approaches across an institution can create inefficiencies or invite risk. This article describes experiences establishing a unified research support office at the Duke University School of Medicine based on a framework of customer support. The Duke Office of Clinical Research was formed in 2012 with a vision that research administration at academic medical centers should help clinical investigators navigate the complex research environment and operationalize research ideas. The office provides an array of services that have received high satisfaction ratings. The authors describe the ongoing culture change necessary for success of the unified research support office. Lessons learned from implementation of the Duke Office of Clinical Research may serve as a model for other institutions undergoing a similar transition.
Odorants create unique and overlapping patterns of olfactory receptor activation, allowing a family of approximately 1,000 murine and 400 human receptors to recognize thousands of odorants. Odorant ...ligands have been published for fewer than 6% of human receptors(1-11). This lack of data is due in part to difficulties functionally expressing these receptors in heterologous systems. Here, we describe a method for expressing the majority of the olfactory receptor family in Hana3A cells, followed by high-throughput assessment of olfactory receptor activation using a luciferase reporter assay. This assay can be used to (1) screen panels of odorants against panels of olfactory receptors; (2) confirm odorant/receptor interaction via dose response curves; and (3) compare receptor activation levels among receptor variants. In our sample data, 328 olfactory receptors were screened against 26 odorants. Odorant/receptor pairs with varying response scores were selected and tested in dose response. These data indicate that a screen is an effective method to enrich for odorant/receptor pairs that will pass a dose response experiment, i.e. receptors that have a bona fide response to an odorant. Therefore, this high-throughput luciferase assay is an effective method to characterize olfactory receptors-an essential step toward a model of odor coding in the mammalian olfactory system.
In both research and therapeutic applications of RNA interference, it is often advantageous to silence several targets simultaneously. Toward this end, several groups have developed vectors that ...utilize the model of endogenously encoded micro (mi) RNAs, where a single RNA polymerase II promoter can drive the expression of multiple interfering RNAs. Stronger pol III promoters have been used to drive individual short hairpin (sh) RNAs, but to date, it has been necessary to repeat the promoter in each silencing cassette to achieve multiplexed expression from a single vector. Here, we show that it is possible to drive polycistronic expression from a single pol III promoter when the interfering RNAs are formatted to resemble miRNAs rather than shRNAs. As many as four miRNAs designed to target hepatitis B virus (HBV) transcripts are shown to be processed and functional in reporter assays as well as in the context of replicating virus in cell culture systems. Although it has been observed that high levels of expression of shRNAs can lead to cytotoxicity, we find no significant evidence in transient transfection assays that the HBV-miRNAs produced by our vectors compete for the activity of endogenously produced miR-122 or for processing of an exogenously expressed miR-EGFP.
RNA interference (RNAi) is a process that can target intracellular RNAs for degradation in a highly sequence-specific manner, making it a powerful tool that is being pursued in both research and ...therapeutic applications. Hepatitis B virus (HBV) is a serious public health problem in need of better treatment options, and aspects of its life cycle make it an excellent target for RNAi-based therapeutics. We have designed a vector that expresses interfering RNAs that target HBV transcripts, including both viral RNA replicative intermediates and mRNAs encoding viral proteins. Our vector design incorporates many features of endogenous microRNA (miRNA) gene organization that are proving useful for the development of reagents for RNAi. In particular, our vector contains an RNA pol II driven gene cassette that leads to tissue-specific expression and efficient processing of multiple interfering RNAs from a single transcript, without the co-expression of any protein product. This vector shows potent silencing of HBV targets in cell culture models of HBV infection. The vector design will be applicable to silencing of additional cellular or disease-related genes.
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