scholarly journals Odor-dependent temporal dynamics in C. elegans odor memory

2018 ◽  
Author(s):  
Jae Im Choi ◽  
Hee Kyung Lee ◽  
Hae Su Kim ◽  
So Young Park ◽  
Kyoung-hye Yoon ◽  
...  
Keyword(s):  
Sensory Neuron ◽  
Temporal Dynamics ◽  
Memory Formation ◽  
Nuclear Accumulation ◽  
C Elegans ◽  
Odor Memory ◽  
Dependent Protein ◽  
Enormous Number ◽  
Specific Odor ◽  
Over Time

Animals sense an enormous number of cues in their environments, and, over time, can form memories and associations to some of these. The nervous system remarkably maintains the specificity of memory to each of the cues. Here we asked whether the nematode Caenorhabditis elegans adjusts the temporal dynamics of odor memory formation depending on the specific odor sensed. C. elegans senses a multitude of odors, and memory formation to some of these odors requires activity of the cGMP-dependent protein kinase EGL-4 in the AWC sensory neuron. We identified a panel of 17 attractive odors, some of which have not been tested before, and determined that the majority of these odors require the AWC primary sensory neuron for sensation. We then devised a novel assay to assess odor behavior over time for a single population of animals. We used this assay to evaluate the temporal dynamics of memory formation to 13 odors and find that memory formation occurs early in some odors and later in others. We then examined EGL-4 localization in early-trending and late-trending odors over time and found that the timing of memory formation correlated with the timing of nuclear accumulation of EGL-4 in the AWC neuron. We demonstrate that odor memory formation in C. elegans can be used as a model to study the timing of memory formation to different sensory cues.

scholarly journals Odor-dependent temporal dynamics in C. elegans odor memory

2018 ◽  
Author(s):  
Jae Im Choi ◽  
Hee Kyung Lee ◽  
Hae Su Kim ◽  
So Young Park ◽  
Kyoung-hye Yoon ◽  
...  
Keyword(s):  
Sensory Neuron ◽  
Temporal Dynamics ◽  
Memory Formation ◽  
Nuclear Accumulation ◽  
C Elegans ◽  
Odor Memory ◽  
Dependent Protein ◽  
Enormous Number ◽  
Specific Odor ◽  
Over Time

Animals sense an enormous number of cues in their environments, and, over time, can form memories and associations to some of these. The nervous system remarkably maintains the specificity of memory to each of the cues. Here we asked whether the nematode Caenorhabditis elegans adjusts the temporal dynamics of odor memory formation depending on the specific odor sensed. C. elegans senses a multitude of odors, and memory formation to some of these odors requires activity of the cGMP-dependent protein kinase EGL-4 in the AWC sensory neuron. We identified a panel of 17 attractive odors, some of which have not been tested before, and determined that the majority of these odors require the AWC primary sensory neuron for sensation. We then devised a novel assay to assess odor behavior over time for a single population of animals. We used this assay to evaluate the temporal dynamics of memory formation to 13 odors and find that memory formation occurs early in some odors and later in others. We then examined EGL-4 localization in early-trending and late-trending odors over time and found that the timing of memory formation correlated with the timing of nuclear accumulation of EGL-4 in the AWC neuron. We demonstrate that odor memory formation in C. elegans can be used as a model to study the timing of memory formation to different sensory cues.

scholarly journals Odor-dependent temporal dynamics inCaenorhabitis elegansadaptation and aversive learning behavior

PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e4956 ◽  
Author(s):  
Jae Im Choi ◽  
Hee Kyung Lee ◽  
Hae Su Kim ◽  
So Young Park ◽  
Tong Young Lee ◽  
...  
Keyword(s):  
Sensory Neuron ◽  
Temporal Dynamics ◽  
Nuclear Accumulation ◽  
Behavior Changes ◽  
Aversive Learning ◽  
Learning Mechanisms ◽  
C Elegans ◽  
Dependent Protein ◽  
Specificity Of Learning ◽  
Over Time

Animals sense an enormous number of cues in their environments, and, over time, can form learned associations and memories with some of these. The nervous system remarkably maintains the specificity of learning and memory to each of the cues. Here we asked whether the nematodeCaenorhabditis elegansadjusts the temporal dynamics of adaptation and aversive learning depending on the specific odor sensed.C. eleganssenses a multitude of odors, and adaptation and learned associations to many of these odors requires activity of the cGMP-dependent protein kinase EGL-4 in the AWC sensory neuron. We identified a panel of 17 attractive odors, some of which have not been tested before, and determined that the majority of these odors require the AWC primary sensory neuron for sensation. We then devised a novel assay to assess odor behavior over time for a single population of animals. We used this assay to evaluate the temporal dynamics of adaptation and aversive learning to 13 odors and find that behavior change occurs early in some odors and later in others. We then examined EGL-4 localization in early-trending and late-trending odors over time. We found that the timing of these behavior changes correlated with the timing of nuclear accumulation of EGL-4 in the AWC neuron suggesting that temporal changes in behavior may be mediated by aversive learning mechanisms. We demonstrate that temporal dynamics of adaptation and aversive learning inC. eleganscan be used as a model to study the timing of memory formation to different sensory cues.

scholarly journals Acute symptoms of mild to moderate COVID-19 are highly heterogeneous across individuals and over time

2021 ◽  
Author(s):  
Thomas L Rodebaugh ◽  
Madelyn R Frumkin ◽  
Angela M Reiersen ◽  
Eric J Lenze ◽  
Michael S Avidan ◽  
...  
Keyword(s):  
Temporal Dynamics ◽  
Survey Methods ◽  
Clinical Care ◽  
Clinical Deterioration ◽  
Symptom Profiles ◽  
Fluctuating Course ◽  
The Common ◽  
Symptom Changes ◽  
Over Time

Abstract Background The symptoms of COVID-19 appear to be heterogenous, and the typical course of these symptoms is unknown. Our objectives were to characterize the common trajectories of COVID-19 symptoms and assess how symptom course predicts other symptom changes as well as clinical deterioration. Methods 162 participants with acute COVID-19 responded to surveys up to 31 times for up to 17 days. Several statistical methods were used to characterize the temporal dynamics of these symptoms. Because nine participants showed clinical deterioration, we explored whether these participants showed any differences in symptom profiles. Results Trajectories varied greatly between individuals, with many having persistently severe symptoms or developing new symptoms several days after being diagnosed. A typical trajectory was for a symptom to improve at a decremental rate, with most symptoms still persisting to some degree at the end of the reporting period. The pattern of symptoms over time suggested a fluctuating course for many patients. Participants who showed clinical deterioration were more likely to present with higher reports of severity of cough and diarrhea. Conclusion The course of symptoms during the initial weeks of COVID-19 is highly heterogeneous and is neither predictable nor easily characterized using typical survey methods. This has implications for clinical care and early-treatment clinical trials. Additional research is needed to determine whether the decelerating improvement pattern seen in our data is related to the phenomenon of patients reporting long-term symptoms, and whether higher symptoms of diarrhea in early illness presages deterioration.

scholarly journals Longitudinal Patterns of Ethical Organisational Culture as a Context for Leaders’ Well-Being: Cumulative Effects Over 6 Years

2021 ◽  
Author(s):  
Mari Huhtala ◽  
Muel Kaptein ◽  
Joona Muotka ◽  
Taru Feldt
Keyword(s):  
Latent Profile Analysis ◽  
Temporal Dynamics ◽  
Ethical Dilemmas ◽  
Extended Period ◽  
Well Being ◽  
Organisational Culture ◽  
Cumulative Effects ◽  
Ethical Culture ◽  
Continuous Increase ◽  
Over Time

AbstractThe aim of this longitudinal study was to investigate the temporal dynamics of ethical organisational culture and how it associates with well-being at work when potential changes in ethical culture are measured over an extended period of 6 years. We used a person-centred study design, which allowed us to detect both typical and atypical patterns of ethical culture stability as well as change among a sample of leaders. Based on latent profile analysis and hierarchical linear modelling we found longitudinal, concurrent relations and cumulative gain and loss cycles between different ethical culture patterns and leaders’ well-being. Leaders in the strongest ethical culture pattern experienced the highest level of work engagement and a decreasing level of ethical dilemmas and stress. Leaders who gave the lowest ratings on ethical culture which also decreased over time reported the highest level of ethical dilemmas, stress, and burnout. They also showed a continuous increase in these negative outcomes over time. Thus, ethical culture has significant cumulative effects on well-being, and these longitudinal effects can be both negative and positive, depending on the experienced strength of the culture’s ethicality.

scholarly journals 520. Longitudinal Analysis of SARS-CoV-2 Viruses in Hospitalized Adults

2020 ◽  
Vol 7 (Supplement_1) ◽  
pp. S325-S326
Author(s):  
Lacy Simons ◽  
Ramon Lorenzo-Redondo ◽  
Hannah Nam ◽  
Scott C Roberts ◽  
Michael G Ison ◽  
...  
Keyword(s):  
Viral Load ◽  
Genome Sequencing ◽  
Viral Genome ◽  
Temporal Dynamics ◽  
Population Level ◽  
Hospital Staff ◽  
Therapeutic Interventions ◽  
Viral Loads ◽  
Qrt Pcr ◽  
Over Time

Abstract Background The rapid spread of SARS-CoV-2, the causative agent of Coronavirus disease 2019 (COVID-19), has been accompanied by the emergence of viral mutations, some of which may have distinct virological and clinical consequences. While whole genome sequencing efforts have worked to map this viral diversity at the population level, little is known about how SARS-CoV-2 may diversify within a host over time. This is particularly important for understanding the emergence of viral resistance to therapeutic interventions and immune pressure. The goal of this study was to assess the change in viral load and viral genome sequence within patients over time and determine if these changes correlate with clinical and/or demographic parameters. Methods Hospitalized patients admitted to Northwestern Memorial Hospital with a positive SARS-CoV-2 test were enrolled in a longitudinal study for the serial collection of nasopharyngeal specimens. Swabs were administered to patients by hospital staff every 4 ± 1 days for up to 32 days or until the patients were discharged. RNA was extracted from each specimen and viral loads were calculated by quantitative reverse transcriptase PCR (qRT-PCR). Specimens with qRT-PCR cycle threshold values less than or equal to 30 were subject to whole viral genome sequencing by reverse transcription, multiplex PCR, and deep sequencing. Variant populations sizes were estimated and subject to phylogenetic analysis relative to publicly available SARS-CoV-2 sequences. Sequence and viral load data were subsequently correlated to available demographic and clinical data. Results 60 patients were enrolled from March 26th to June 20th, 2020. We observed an overall decrease in nasopharyngeal viral load over time across all patients. However, the temporal dynamics of viral load differed on a patient-by-patient basis. Several mutations were also observed to have emerged within patients over time. Distribution of SARS-CoV-2 viral loads in serially collected nasopharyngeal swabs in hospitalized adults as determined by qRT-PCR. Samples were collected every 4 ± 1 days (T#1–8) and viral load is displayed by log(copy number). Conclusion These data indicate that SARS-CoV-2 viral loads in the nasopharynx decrease over time and that the virus can accumulate mutations during replication within individual patients. Future studies will examine if some of these mutations may provide fitness advantages in the presence of therapeutic and/or immune selective pressures. Disclosures Michael G. Ison, MD MS, AlloVir (Consultant)

scholarly journals Temporal Dynamics of Cloacal Microbiota in Adult Laying Chickens With and Without Access to an Outdoor Range

2021 ◽  
Vol 11 ◽  
Author(s):  
Janneke Schreuder ◽  
Francisca C. Velkers ◽  
Alex Bossers ◽  
Ruth J. Bouwstra ◽  
Willem F. de Boer ◽  
...  
Keyword(s):  
Microbial Community ◽  
Community Composition ◽  
Intestinal Microbiota ◽  
Environmental Changes ◽  
Temporal Dynamics ◽  
Microbial Community Composition ◽  
Sudden Change ◽  
Rrna Gene ◽  
Poultry House ◽  
Over Time

Associations between animal health and performance, and the host’s microbiota have been recently established. In poultry, changes in the intestinal microbiota have been linked to housing conditions and host development, but how the intestinal microbiota respond to environmental changes under farm conditions is less well understood. To gain insight into the microbial responses following a change in the host’s immediate environment, we monitored four indoor flocks of adult laying chickens three times over 16 weeks, during which two flocks were given access to an outdoor range, and two were kept indoors. To assess changes in the chickens’ microbiota over time, we collected cloacal swabs of 10 hens per flock and performed 16S rRNA gene amplicon sequencing. The poultry house (i.e., the stable in which flocks were housed) and sampling time explained 9.2 and 4.4% of the variation in the microbial community composition of the flocks, respectively. Remarkably, access to an outdoor range had no detectable effect on microbial community composition, the variability of microbiota among chickens of the same flock, or microbiota richness, but the microbiota of outdoor flocks became more even over time. Fluctuations in the composition of the microbiota over time within each poultry house were mainly driven by turnover in rare, rather than dominant, taxa and were unique for each flock. We identified 16 amplicon sequence variants that were differentially abundant over time between indoor and outdoor housed chickens, however none were consistently higher or lower across all chickens of one housing type over time. Our study shows that cloacal microbiota community composition in adult layers is stable following a sudden change in environment, and that temporal fluctuations are unique to each flock. By exploring microbiota of adult poultry flocks within commercial settings, our study sheds light on how the chickens’ immediate environment affects the microbiota composition.

scholarly journals Progressive recruitment of distal MEC-4 channels determines touch response strength in C. elegans

2019 ◽  
Author(s):  
S. Katta ◽  
A. Sanzeni ◽  
A. Das ◽  
M. Vergassola ◽  
M.B. Goodman
Keyword(s):  
Temporal Dynamics ◽  
Mechanical Strain ◽  
Tissue Mechanics ◽  
Mechanical Stimuli ◽  
Patch Clamp Recording ◽  
Open Probability ◽  
C Elegans ◽  
Somatosensory Neurons ◽  
Touch Response

AbstractTouch deforms, or strains, the skin beyond the immediate point of contact. The spatiotemporal nature of the touch-induced strain fields depend on the mechanical properties of the skin and the tissues below. Somatosensory neurons that sense touch branch out within the skin and rely on a set of mechano-electrical transduction channels distributed within their dendrites to detect mechanical stimuli. Here, we sought to understand how tissue mechanics shape touch-induced mechanical strain across the skin over time and how individual channels located in different regions of the strain field contribute to the overall touch response. We leveraged C. elegans’ touch receptor neurons (TRNs) as a simple model amenable to in vivo whole-cell patch clamp recording and an integrated experimental-computational approach to dissect the mechanisms underlying the spatial and temporal dynamics that we observed. Consistent with the idea that strain is produced at a distance, we show that delivering strong stimuli outside the anatomical extent of the neuron is sufficient to evoke MRCs. The amplitude and kinetics of the MRCs depended on both stimulus displacement and speed. Finally, we found that the main factor responsible for touch sensitivity is the recruitment of progressively more distant channels by stronger stimuli, rather than modulation of channel open probability. This principle may generalize to somatosensory neurons with more complex morphologies.SummaryThrough experiment and simulation, Katta et al. reveal that pushing faster and deeper recruits more and more distant mechano-electrical transduction channels during touch. The net result is a dynamic receptive field whose size and shape depends on tissue mechanics, stimulus parameters, and channel distribution within sensory neurons.

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