scholarly journals A quantitative imaging-based screen reveals the exocyst as a network hub connecting endocytosis and exocytosis

2015 ◽  
Vol 26 (13) ◽  
pp. 2519-2534 ◽  
Author(s):  
Mini Jose ◽  
Sylvain Tollis ◽  
Deepak Nair ◽  
Romain Mitteau ◽  
Christophe Velours ◽  
...  
Keyword(s):  
Systems Analysis ◽  
Spatial Organization ◽  
Quantitative Imaging ◽  
Golgi Vesicle ◽  
Biological Processes ◽  
Cellular Polarity ◽  
Vesicle Dynamics ◽  
Maintenance Systems ◽  
Resolution Single ◽  
Single Vesicle

The coupling of endocytosis and exocytosis underlies fundamental biological processes ranging from fertilization to neuronal activity and cellular polarity. However, the mechanisms governing the spatial organization of endocytosis and exocytosis require clarification. Using a quantitative imaging-based screen in budding yeast, we identified 89 mutants displaying defects in the localization of either one or both pathways. High-resolution single-vesicle tracking revealed that the endocytic and exocytic mutants she4∆ and bud6∆ alter post-Golgi vesicle dynamics in opposite ways. The endocytic and exocytic pathways display strong interdependence during polarity establishment while being more independent during polarity maintenance. Systems analysis identified the exocyst complex as a key network hub, rich in genetic interactions with endocytic and exocytic components. Exocyst mutants displayed altered endocytic and post-Golgi vesicle dynamics and interspersed endocytic and exocytic domains compared with control cells. These data are consistent with an important role for the exocyst in coordinating endocytosis and exocytosis.

Fluorescent potentiometric dyes for membrane-potential imaging

1994 ◽  
Vol 52 ◽  
pp. 166-167
Author(s):  
Leslie M. Loew
Keyword(s):  
Membrane Potential ◽  
Single Cells ◽  
Quantitative Imaging ◽  
Optical Recording ◽  
Biological Processes ◽  
Major Focus ◽  
The Past ◽  
Excitable Systems ◽  
Major Application ◽  
The Impact

A major application of potentiometric dyes has been the multisite optical recording of electrical activity in excitable systems. After being championed by L.B. Cohen and his colleagues for the past 20 years, the impact of this technology is rapidly being felt and is spreading to an increasing number of neuroscience laboratories. A second class of experiments involves using dyes to image membrane potential distributions in single cells by digital imaging microscopy - a major focus of this lab. These studies usually do not require the temporal resolution of multisite optical recording, being primarily focussed on slow cell biological processes, and therefore can achieve much higher spatial resolution. We have developed 2 methods for quantitative imaging of membrane potential. One method uses dual wavelength imaging of membrane-staining dyes and the other uses quantitative 3D imaging of a fluorescent lipophilic cation; the dyes used in each case were synthesized for this purpose in this laboratory.

scholarly journals Incorporating radiomics into clinical trials: expert consensus on considerations for data-driven compared to biologically driven quantitative biomarkers

2021 ◽  
Author(s):  
Laure Fournier ◽  
Lena Costaridou ◽  
Luc Bidaut ◽  
Nicolas Michoux ◽  
Frederic E. Lecouvet ◽  
...  
Keyword(s):  
Clinical Trials ◽  
Quantitative Imaging ◽  
A Priori ◽  
External Validation ◽  
Data Driven ◽  
Imaging Biomarkers ◽  
Clinical Validation ◽  
Biological Processes ◽  
Imaging Data ◽  
Selection Of

Abstract Existing quantitative imaging biomarkers (QIBs) are associated with known biological tissue characteristics and follow a well-understood path of technical, biological and clinical validation before incorporation into clinical trials. In radiomics, novel data-driven processes extract numerous visually imperceptible statistical features from the imaging data with no a priori assumptions on their correlation with biological processes. The selection of relevant features (radiomic signature) and incorporation into clinical trials therefore requires additional considerations to ensure meaningful imaging endpoints. Also, the number of radiomic features tested means that power calculations would result in sample sizes impossible to achieve within clinical trials. This article examines how the process of standardising and validating data-driven imaging biomarkers differs from those based on biological associations. Radiomic signatures are best developed initially on datasets that represent diversity of acquisition protocols as well as diversity of disease and of normal findings, rather than within clinical trials with standardised and optimised protocols as this would risk the selection of radiomic features being linked to the imaging process rather than the pathology. Normalisation through discretisation and feature harmonisation are essential pre-processing steps. Biological correlation may be performed after the technical and clinical validity of a radiomic signature is established, but is not mandatory. Feature selection may be part of discovery within a radiomics-specific trial or represent exploratory endpoints within an established trial; a previously validated radiomic signature may even be used as a primary/secondary endpoint, particularly if associations are demonstrated with specific biological processes and pathways being targeted within clinical trials. Key Points • Data-driven processes like radiomics risk false discoveries due to high-dimensionality of the dataset compared to sample size, making adequate diversity of the data, cross-validation and external validation essential to mitigate the risks of spurious associations and overfitting. • Use of radiomic signatures within clinical trials requires multistep standardisation of image acquisition, image analysis and data mining processes. • Biological correlation may be established after clinical validation but is not mandatory.

scholarly journals Quantitative Imaging of Gut Microbiota Spatial Organization

2015 ◽  
Vol 18 (4) ◽  
pp. 478-488 ◽  
Author(s):  
Kristen A. Earle ◽  
Gabriel Billings ◽  
Michael Sigal ◽  
Joshua S. Lichtman ◽  
Gunnar C. Hansson ◽  
...  
Keyword(s):  
Gut Microbiota ◽  
Spatial Organization ◽  
Quantitative Imaging

scholarly journals Systems analysis reveals complex biological processes during virus infection fate decisions

2019 ◽  
Vol 29 (6) ◽  
pp. 907-919 ◽  
Author(s):  
Jordi Argilaguet ◽  
Mireia Pedragosa ◽  
Anna Esteve-Codina ◽  
Graciela Riera ◽  
Enric Vidal ◽  
...  
Keyword(s):  
Virus Infection ◽  
Systems Analysis ◽  
Biological Processes

Capturing Processes

2018 ◽  
Author(s):  
Laura Nuño de la Rosa
Keyword(s):  
Developmental Biology ◽  
Quantitative Imaging ◽  
Time Lapse ◽  
First Century ◽  
Biological Processes ◽  
In Vivo Microscopy ◽  
Developmental Processes ◽  
Biological Entities ◽  
Time Lapse Imaging

While a processual view of biological entities might be said to be congenial to embryologists, the intractability and speed of developmental processes traditionally led to an epistemological abandon of processes in favour of the advantages of discretizing ontogenies in arrays of patterns. It is not until the turn of the twenty-first century that the digital embryos obtained from in vivo microscopy have started to replace developmental series as the reference representations of development. This chapter looks at how new microscopy, molecular, and computer technologies for reconstructing biological processes are contributing to a processual understanding of development. First it investigates how time-lapse imaging has brought with it a radical dynamization, not only of the images, but also of the theories of development themselves. Next it explores the role that imaging technologies have played in the return of organicism in developmental biology. Finally, it focuses on how quantitative imaging contributes to the explanatory modelling of developmental processes.

scholarly journals Conformational changes in common monosaccharides caused by per-O-sulfation

2019 ◽  
Vol 91 (7) ◽  
pp. 1223-1229
Author(s):  
Alexey G. Gerbst ◽  
Vadim B. Krylov ◽  
Nikolay E. Nifantiev
Keyword(s):  
Conformational Changes ◽  
Molecular Modelling ◽  
Spatial Organization ◽  
Coagulation Factors ◽  
Biological Properties ◽  
Side Chain ◽  
Biological Processes ◽  
High Demand ◽  
Blood Coagulation Factors ◽  
Protein Receptors

Abstract Polysulfated carbohydrates play an important role in many biological processes because of their ability to bind to various protein receptors such as different growth factors, blood coagulation factors, adhesion lectins etc. Precise information about spatial organization of sulfated derivatives is of high demand for molecular modelling of such interactions as well as for understanding of the mechanism of pyranoside-into-furanoside rearrangement. In this review we summarize the changes recently revealed for the conformations of common pyranosides and furanosides upon total O-sulfation which were studied by means of NMR spectroscopy as well as molecular modelling. It was found that pentoses, being more flexible, undergo complete conformational chair inversion. Meanwhile, for hexoses the situation strongly depends on the monosaccharide configuration. Conformational changes are most pronounced in gluco-compounds though quantum chemical calculations helped to establish that no complete chair inversion occurred. In furanosides distortions of two types were observed: either the ring conformation or the conformation of the side chain changed. The presented data may be used for the analysis of chemical, physical and biological properties of sulfated carbohydrates.

GFP-golvesin constructs to study Golgi tubulation and post-Golgi vesicle dynamics in phagocytosis

2004 ◽  
Vol 83 (6) ◽  
pp. 297-303 ◽  
Author(s):  
Günther Gerisch ◽  
Aleksander Benjak ◽  
Jana Köhler ◽  
Igor Weber ◽  
Natalie Schneider
Keyword(s):  
Golgi Vesicle ◽  
Vesicle Dynamics
Sign in / Sign up

Export Citation Format

Share Document