scholarly journals C. elegans chromosomes connect to centrosomes by anchoring into the spindle network

2016 ◽  
Author(s):  
Stefanie Redemann ◽  
Johannes Baumgart ◽  
Norbert Lindow ◽  
Sebastian Fürthauer ◽  
Ehssan Nazockdast ◽  
...  
Keyword(s):  
Light Microscopy ◽  
Mitotic Spindle ◽  
Live Cell Imaging ◽  
Large Scale ◽  
Cell Imaging ◽  
Electron Tomography ◽  
Mitotic Spindles ◽  
C Elegans ◽  
Microtubule Growth ◽  
Segregation Of Chromosomes

AbstractThe mitotic spindle ensures the faithful segregation of chromosomes. To discover the nature of the crucial centrosome-to-chromosome connection during mitosis, we combined the first large-scale serial electron tomography of whole mitotic spindles in early C. elegans embryos with live-cell imaging. Using tomography, we reconstructed the positions of all microtubules in 3D, and identified their plus- and minus-ends. We classified them as kinetochore (KMTs), spindle (SMTs), or astral microtubules (AMTs) according to their positions, and quantified distinct properties of each class. While our light microscopy and mutant studies show that microtubules are nucleated from the centrosomes, we find only a few KMTs are directly connected to the centrosomes. Indeed, by quantitatively analysing several models of microtubule growth, we conclude that minus-ends of KMTs have selectively detached and depolymerized from the centrosome. In toto, our results show that the connection between centrosomes and chromosomes is mediated by an anchoring into the entire spindle network and that any direct connections through KMTs are few and likely very transient.

scholarly journals Microtubule re-organization during female meiosis in C. elegans

2020 ◽  
Author(s):  
Ina Lantzsch ◽  
Che-Hang Yu ◽  
Hossein Yazdkhasti ◽  
Norbert Lindow ◽  
Erik Szentgyörgyi ◽  
...  
Keyword(s):  
Large Scale ◽  
Electron Tomography ◽  
Morphological Changes ◽  
Average Length ◽  
Length Distribution ◽  
C Elegans ◽  
Model Predictions ◽  
Meiotic Spindles ◽  
Microtubule Growth ◽  
Turn Over

AbstractThe female meiotic spindles of most animals are acentrosomal and undergo drastic morphological changes while transitioning from metaphase to anaphase. The ultra-structure of acentrosomal spindles, and how this enables such dramatic rearrangements remains largely unknown.To address this, we applied light microscopy, large-scale electron tomography and mathematical modeling of female meiotic C. elegans spindles undergoing the transition from metaphase to anaphase. Combining these approaches, we find that meiotic spindles are dynamic arrays of short microtubules that turn over on second time scales. The results show that the transition from metaphase to anaphase correlates with an increase in the number of microtubules and a decrease of their average length. To understand the mechanisms that drive this transition, we developed a mathematical model for the microtubule length distribution that considers microtubule growth, catastrophe, and severing. Using Bayesian inference to compare model predictions and data, we find that microtubule turn-over is the major driver of the observed large-scale reorganizations. Our data suggest that cutting of microtubules occurs, but that most microtubules are not severed before undergoing catastrophe.

scholarly journals C. elegans neurons have functional dendritic spines

eLife ◽  
2019 ◽  
Vol 8 ◽  
Author(s):  
Andrea Cuentas-Condori ◽  
Ben Mulcahy ◽  
Siwei He ◽  
Sierra Palumbos ◽  
Mei Zhen ◽  
...  
Keyword(s):  
Motor Neurons ◽  
Dendritic Spines ◽  
Live Cell Imaging ◽  
Cell Imaging ◽  
Super Resolution ◽  
Live Cell ◽  
Model Organisms ◽  
Spine Density ◽  
C Elegans ◽  
Spine Function

Dendritic spines are specialized postsynaptic structures that transduce presynaptic signals, are regulated by neural activity and correlated with learning and memory. Most studies of spine function have focused on the mammalian nervous system. However, spine-like protrusions have been reported in C. elegans (Philbrook et al., 2018), suggesting that the experimental advantages of smaller model organisms could be exploited to study the biology of dendritic spines. Here, we used super-resolution microscopy, electron microscopy, live-cell imaging and genetics to show that C. elegans motor neurons have functional dendritic spines that: (1) are structurally defined by a dynamic actin cytoskeleton; (2) appose presynaptic dense projections; (3) localize ER and ribosomes; (4) display calcium transients triggered by presynaptic activity and propagated by internal Ca++ stores; (5) respond to activity-dependent signals that regulate spine density. These studies provide a solid foundation for a new experimental paradigm that exploits the power of C. elegans genetics and live-cell imaging for fundamental studies of dendritic spine morphogenesis and function.

High-Voltage Electron Tomography of the Early C. elegans Mitotic Spindle

2003 ◽  
Vol 9 (S03) ◽  
pp. 384-385
Author(s):  
Eileen T. O'Toole ◽  
Kent L. McDonald ◽  
Jana Mäntler ◽  
J. Richard McIntosh ◽  
Anthony A. Hyman ◽  
...  
Keyword(s):  
High Voltage ◽  
Mitotic Spindle ◽  
Electron Tomography ◽  
C Elegans ◽  
Voltage Electron ◽  
High Voltage Electron

scholarly journals Shedding light on biology of bacterial cells

2016 ◽  
Vol 371 (1707) ◽  
pp. 20150499 ◽  
Author(s):  
Johannes P. Schneider ◽  
Marek Basler
Keyword(s):  
Light Microscopy ◽  
Live Cell Imaging ◽  
Spatial Organization ◽  
Cell Imaging ◽  
Live Cell ◽  
Bacterial Cells ◽  
Resolution Limit ◽  
Detection Techniques ◽  
Living Organisms ◽  
Cellular Components

To understand basic principles of living organisms one has to know many different properties of all cellular components, their mutual interactions but also their amounts and spatial organization. Live-cell imaging is one possible approach to obtain such data. To get multiple snapshots of a cellular process, the imaging approach has to be gentle enough to not disrupt basic functions of the cell but also have high temporal and spatial resolution to detect and describe the changes. Light microscopy has become a method of choice and since its early development over 300 years ago revolutionized our understanding of living organisms. As most cellular components are indistinguishable from the rest of the cellular contents, the second revolution came from a discovery of specific labelling techniques, such as fusions to fluorescent proteins that allowed specific tracking of a component of interest. Currently, several different tags can be tracked independently and this allows us to simultaneously monitor the dynamics of several cellular components and from the correlation of their dynamics to infer their respective functions. It is, therefore, not surprising that live-cell fluorescence microscopy significantly advanced our understanding of basic cellular processes. Current cameras are fast enough to detect changes with millisecond time resolution and are sensitive enough to detect even a few photons per pixel. Together with constant improvement of properties of fluorescent tags, it is now possible to track single molecules in living cells over an extended period of time with a great temporal resolution. The parallel development of new illumination and detection techniques allowed breaking the diffraction barrier and thus further pushed the resolution limit of light microscopy. In this review, we would like to cover recent advances in live-cell imaging technology relevant to bacterial cells and provide a few examples of research that has been possible due to imaging. This article is part of the themed issue ‘The new bacteriology’.

Large-Scale Ordered Plastic Nanopillars for Quantitative Live-Cell Imaging

Small ◽  
2009 ◽  
Vol 5 (4) ◽  
pp. 449-453 ◽  
Author(s):  
Kheya Sengupta ◽  
Eric Moyen ◽  
Magali Macé ◽  
Anne-Marie Benoliel ◽  
Anne Pierres ◽  
...  
Keyword(s):  
Live Cell Imaging ◽  
Large Scale ◽  
Cell Imaging ◽  
Live Cell

scholarly journals cAMP controls a trafficking mechanism that directs the neuron specificity and subcellular placement of electrical synapses

2021 ◽  
Author(s):  
Sierra Palumbos ◽  
Rachel Skelton ◽  
Rebecca McWhirter ◽  
Amanda Mitchell ◽  
Isaiah Swann ◽  
...  
Keyword(s):  
Nervous System ◽  
Gap Junction ◽  
Motor Neurons ◽  
Live Cell Imaging ◽  
Cell Imaging ◽  
Electrical Synapse ◽  
Transcriptional Program ◽  
Electrical Synapses ◽  
C Elegans

Electrical synapses are established between specific neurons and within distinct subcellular compartments, but the mechanisms that direct gap junction assembly in the nervous system are largely unknown. Here we show that a transcriptional program tunes cAMP signaling to direct the neuron-specific assembly and placement of electrical synapses in the C. elegans motor circuit. For these studies, we use live cell imaging to visualize electrical synapses in vivo and a novel optogenetic assay to confirm that they are functional. In VA motor neurons, the UNC-4 transcription factor blocks expression of cAMP antagonists that promote gap junction miswiring. In unc-4 mutants, VA electrical synapses are established with an alternative synaptic partner and are repositioned from the VA axon to soma. We show that cAMP counters these effects by driving gap junction trafficking into the VA axon for electrical synapse assembly. Thus, our experiments in an intact nervous system establish that cAMP regulates gap junction trafficking for the biogenesis of electrical synapses.

The Large-Scale Digital Cell Analysis System: an open system for nonperturbing live cell imaging

2007 ◽  
Vol 228 (3) ◽  
pp. 296-308 ◽  
Author(s):  
PAUL J. DAVIS ◽  
ELIZABETH A. KOSMACEK ◽  
YUANSHENG SUN ◽  
FIORENZA IANZINI ◽  
MICHAEL A. MACKEY
Keyword(s):  
Open System ◽  
Live Cell Imaging ◽  
Large Scale ◽  
Cell Imaging ◽  
Live Cell ◽  
Cell Analysis ◽  
Analysis System ◽  
Digital Cell Analysis
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