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  • 1
    In: Microbiology Spectrum, American Society for Microbiology, Vol. 9, No. 1 ( 2021-09-03)
    Abstract: The malaria parasite has a complex life cycle exhibiting phenotypic and morphogenic variations in two different hosts by existing in heterogeneous developmental states. To investigate this cellular heterogeneity of the parasite within the human host, we performed single-cell RNA sequencing of synchronized Plasmodium cells under control and temperature treatment conditions. Using the Malaria Cell Atlas ( https://www.sanger.ac.uk/science/tools/mca ) as a guide, we identified 9 subtypes of the parasite distributed across known intraerythrocytic stages. Interestingly, temperature treatment results in the upregulation of the AP2-G gene, the master regulator of sexual development in a small subpopulation of the parasites. Moreover, we identified a heterogeneous stress-responsive subpopulation (clusters 5, 6, and 7 [∼10% of the total population]) that exhibits upregulation of stress response pathways under normal growth conditions. We also developed an online exploratory tool that will provide new insights into gene function under normal and temperature stress conditions. Thus, our study reveals important insights into cell-to-cell heterogeneity in the parasite population under temperature treatment that will be instrumental toward a mechanistic understanding of cellular adaptation and population dynamics in Plasmodium falciparum . IMPORTANCE The malaria parasite has a complex life cycle exhibiting phenotypic variations in two different hosts accompanied by cell-to-cell variability that is important for stress tolerance, immune evasion, and drug resistance. To investigate cellular heterogeneity determined by gene expression, we performed single-cell RNA sequencing (scRNA-seq) of about 12,000 synchronized Plasmodium cells under physiologically relevant normal (37°C) and temperature stress (40°C) conditions phenocopying the cyclic bouts of fever experienced during malarial infection. In this study, we found that parasites exhibit transcriptional heterogeneity in an otherwise morphologically synchronized culture. Also, a subset of parasites is continually committed to gametocytogenesis and stress-responsive pathways. These observations have important implications for understanding the mechanisms of drug resistance generation and vaccine development against the malaria parasite.
    Type of Medium: Online Resource
    ISSN: 2165-0497
    Language: English
    Publisher: American Society for Microbiology
    Publication Date: 2021
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  • 2
    In: Plant Signaling & Behavior, Informa UK Limited, Vol. 8, No. 10 ( 2013-10), p. e26891-
    Type of Medium: Online Resource
    ISSN: 1559-2324
    Language: English
    Publisher: Informa UK Limited
    Publication Date: 2013
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    SSG: 12
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  • 3
    In: Cancer Research, American Association for Cancer Research (AACR), Vol. 83, No. 7_Supplement ( 2023-04-04), p. 1120-1120
    Abstract: Translational oncology studies increasingly emphasize deriving hypotheses from single-cell datasets by evaluating groups of patients (e.g., treated vs. untreated, responders vs. non-responders, early vs. late-stage tumors) for differences in gene signatures/pathways to guide subsequent investigations. However, when evaluating these questions using tumor single-cell data, current statistical methods for this task are limited in two major aspects: (i) They are not representative of the hierarchical nature of tumor single-cell datasets (where cells are more similar within the patient than between patients); and (ii) They often do not contextualize statistical significance (p-values) in the context of variability that is expected biologically between patients. This can lead to molecular hypotheses that are skewed by patient-specific biology with high false positive rates. To address these challenges, we developed a nonparametric statistical method, BEANIE (group Biology EstimAtioN in sIngle cEll), for estimating group biology in single-cell transcriptomic datasets. BEANIE uses monte carlo simulations to estimate the p-value distribution for the gene signature of interest and normalizes with respect to a background distribution of the expected patient-to-patient variability. The method then performs leave-one-out cross-validation to infer robustness of the gene signatures to patient exclusion. We applied our method to public cancer single-cell datasets to evaluate candidate differences in tumor cell populations between known groups. When comparing tumor cell programs derived from treatment-naive vs. chemotherapy-treated Triple-Negative Breast Cancer (TNBC) patients, BEANIE identified upregulation of hallmark gene signatures for fatty acid metabolism and hypoxia to be statistically significant and robust in the treatment-naive group, indicative of response to chemotherapy treatment. We also compared BEANIE to conventional methods like Mann-Whitney U (MWU) test followed by Benjamini-Hochberg (BH) correction and Generalized Linear Models (GLM). MWU test and GLM also identified these signatures to be upregulated, but they additionally identified other immune cell gene signatures like T-cell markers, B-cell markers and NK cell markers, to also be upregulated, which was not expected since we were comparing between tumor cells. Similarly, BEANIE identified candidate tumor cell intrinsic programs relevant to hypotheses in lung cancer patients (early vs. late-stage) and melanoma patients (Immune Checkpoint Blockade (ICB)-naive vs. ICB-treated). Therefore, BEANIE greatly increased the specificity of analysis, and reduced false positive rates. This method is publicly available and may overcome existing methodological limitations to guide tumor-intrinsic hypothesis generation in rapidly growing clinical cancer single-cell cohorts. Citation Format: Shreya Johri, Kevin Bi, Breanna M. Titchen, Jingxin Fu, Jake Conway, Jett Crowdis, Natalie I. Volkes, Zenghua Fan, Lawrence Fong, Jihye Park, David Liu, Meng Xiao He, Eliezer M. Van Allen. Dissecting tumor cell programs through group biology estimation in clinical single-cell transcriptomics [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 1120.
    Type of Medium: Online Resource
    ISSN: 1538-7445
    Language: English
    Publisher: American Association for Cancer Research (AACR)
    Publication Date: 2023
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  • 4
    In: Science Advances, American Association for the Advancement of Science (AAAS), Vol. 9, No. 39 ( 2023-09-29)
    Abstract: Neuroendocrine tumors bear hallmarks of early gastrointestinal development and an immunosuppressive myeloid microenvironment.
    Type of Medium: Online Resource
    ISSN: 2375-2548
    Language: English
    Publisher: American Association for the Advancement of Science (AAAS)
    Publication Date: 2023
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  • 5
    Online Resource
    Online Resource
    SAGE Publications ; 2010
    In:  Proceedings of the Human Factors and Ergonomics Society Annual Meeting Vol. 54, No. 23 ( 2010-09), p. 1971-1975
    In: Proceedings of the Human Factors and Ergonomics Society Annual Meeting, SAGE Publications, Vol. 54, No. 23 ( 2010-09), p. 1971-1975
    Abstract: Today, designers have access to larger amounts of content information and consequently, groups of people working collaboratively can access and communicate information both synchronously and asynchronously. The role of pen-based technologies, and in particular, the tablet PC, has also played an increasingly important role in how designers communicate through external representations. By identifying the specific effects of the tablet PCs on team communication and matching design practices we investigate how technology and communication shape team design practices. It is also important to investigate the degree to which designers adopt and utilize these unique features of the technology. In addition, the impact of attitudes on usage is of important interest, due to its relationship with the adoption and implementation of tablet PC features. Under a previous project, students were assigned into teams based on prior experiences, and tasked with creating an innovative design solution for a client. This study will use the observational data collected from that project, coupled with researcher field notes, focus group interviews, and background questionnaires to investigate if the unique features of Tablet PCs shape team communication and corresponding design practices. In addition, I investigate whether teams' previous experience with technology has an effect on design practice. Initial results show teams who had previous experience with technology are more likely to use specific features of the tablet PC to facilitate communication compared to those with little prior experience in technology. Teams leverage the features of the tablet PC to assist in the design process produced the more innovative design solutions compared to those who use methods that are more traditional.
    Type of Medium: Online Resource
    ISSN: 2169-5067 , 1071-1813
    Language: English
    Publisher: SAGE Publications
    Publication Date: 2010
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