Variable expression of gliding and swimming motility in Deleya marina

1991 ◽  
Vol 37 (11) ◽  
pp. 808-814 ◽  
Author(s):  
C. Shea ◽  
J. W. Nunley ◽  
H. E. Smith-Somerville
Keyword(s):  
Growth Pattern ◽  
Single Cells ◽  
Cell Movement ◽  
Gliding Motility ◽  
Electron Microscopic ◽  
Marine Agar ◽  
Swimming Motility ◽  
Variable Expression ◽  
Pattern Characteristic ◽  
Deleya Marina

Surface-associated motility has been observed in the Deleya marina type strain ATCC 25374 (strain 219). Slime tracks and a complex growth pattern, characteristic of gliding motility, developed on semisolid marine-agar motility plates. Cell movement observed by light microscopy consisted of rapid glides and flips by single cells and groups of cells. Following the development of the gliding cell growth pattern, a subpopulation of swimming cells appeared. The variation in motility was random and reversible in subculture. Electron microscopic comparisons of cells of the two motility types showed that gliding cells had no obvious motility organelles, whereas swimming cells had polar flagella. Variable expression of gliding and swimming motility was also observed in D. marina strain 140 (ATCC 27129) and in two other species of the Deleya genus. Key words: gliding, morphological variation, Deleya, biofouling.

Cell Morphologies and Contacts in Annual Fish Embryos

1980 ◽  
Vol 38 ◽  
pp. 706-707
Author(s):  
Roland Lesseps
Keyword(s):  
Developmental Stages ◽  
Single Cells ◽  
Cell Movement ◽  
Time Lapse ◽  
Microscopic Investigation ◽  
Electron Microscopic Investigation ◽  
Electron Microscopic ◽  
Annual Fish ◽  
Fish Embryos

During epiboly and early dispersed stages, the deep blastomeres of annual fish embryos emigrate from the blastodisc to wander as easily visible single cells in the narrow space between the yolk synctial layer (YSL) and the enveloping cell layer (ECL). Subsequently these deep blastomeres reaggregate and eventually form the definitive embryo. We are studying these morphogen-etic cell movements and the controls that may exist upon cell movement in vivo. Time-lapse cinemicrophotography showed three types of cell movement by the deep blastomeres during epiboly through reaggregation stages [1], The present electron microscopic investigation was undertaken to reveal further details of the intercellular contacts during these developmental stages.

scholarly journals Self-organized cell migration across scales – from single cell movement to tissue formation

Development ◽  
2021 ◽  
Vol 148 (7) ◽  
pp. dev191767
Author(s):  
Jessica Stock ◽  
Andrea Pauli
Keyword(s):  
Cell Migration ◽  
Multiple Scales ◽  
Single Cells ◽  
Cell Movement ◽  
Biological Response ◽  
Collective Cell Migration ◽  
Theoretical Concepts ◽  
Self Organizing

ABSTRACTSelf-organization is a key feature of many biological and developmental processes, including cell migration. Although cell migration has traditionally been viewed as a biological response to extrinsic signals, advances within the past two decades have highlighted the importance of intrinsic self-organizing properties to direct cell migration on multiple scales. In this Review, we will explore self-organizing mechanisms that lay the foundation for both single and collective cell migration. Based on in vitro and in vivo examples, we will discuss theoretical concepts that underlie the persistent migration of single cells in the absence of directional guidance cues, and the formation of an autonomous cell collective that drives coordinated migration. Finally, we highlight the general implications of self-organizing principles guiding cell migration for biological and medical research.

scholarly journals Unusual Kinetic and Structural Properties Control Rapid Assembly and Turnover of Actin in the Parasite Toxoplasma gondii

2006 ◽  
Vol 17 (2) ◽  
pp. 895-906 ◽  
Author(s):  
Nivedita Sahoo ◽  
Wandy Beatty ◽  
John Heuser ◽  
David Sept ◽  
L. David Sibley
Keyword(s):  
Critical Concentration ◽  
Microscopic Analysis ◽  
Protozoan Parasite ◽  
Gliding Motility ◽  
Host Cells ◽  
Filamentous Actin ◽  
Unusual Behavior ◽  
Electron Microscopic ◽  
Unusual Form ◽  
Kinetics Of

Toxoplasma is a protozoan parasite in the phylum Apicomplexa, which contains a number of medically important parasites that rely on a highly unusual form of motility termed gliding to actively penetrate their host cells. Parasite actin filaments regulate gliding motility, yet paradoxically filamentous actin is rarely detected in these parasites. To investigate the kinetics of this unusual parasite actin, we expressed TgACT1 in baculovirus and purified it to homogeneity. Biochemical analysis showed that Toxoplasma actin (TgACT1) rapidly polymerized into filaments at a critical concentration that was 3-4-fold lower than conventional actins, yet it failed to copolymerize with mammalian actin. Electron microscopic analysis revealed that TgACT1 filaments were 10 times shorter and less stable than rabbit actin. Phylogenetic comparison of actins revealed a limited number of apicomplexan-specific residues that likely govern the unusual behavior of parasite actin. Molecular modeling identified several key alterations that affect interactions between monomers and that are predicted to destabilize filaments. Our findings suggest that conserved molecular differences in parasite actin favor rapid cycles of assembly and disassembly that govern the unusual form of gliding motility utilized by apicomplexans.

scholarly journals The Cauliflower Mosaic Virus Virion-Associated Protein Is Dispensable for Viral Replication in Single Cells

2002 ◽  
Vol 76 (18) ◽  
pp. 9457-9464 ◽  
Author(s):  
Kappei Kobayashi ◽  
Seiji Tsuge ◽  
Livia Stavolone ◽  
Thomas Hohn
Keyword(s):  
Mosaic Virus ◽  
Single Cells ◽  
Electron Microscopic Examination ◽  
Aphid Transmission ◽  
Cauliflower Mosaic Virus ◽  
Wild Type Virus ◽  
Transmission Factor ◽  
Electron Microscopic ◽  
Additional Function ◽  
Frameshift Mutant

ABSTRACT Cauliflower mosaic virus (CaMV) open reading frame III (ORF III) codes for a virion-associated protein (Vap), which is one of two viral proteins essential for aphid transmission. However, unlike the aphid transmission factor encoded by CaMV ORF II, Vap is also essential for systemic infection, suggesting that it is a multifunctional protein. To elucidate the additional function or functions of Vap, we tested the replication of noninfectious ORF III-defective mutants in transfected turnip protoplasts. PCR and Western blot analyses revealed that CaMV replication had occurred with an efficiency similar to that of wild-type virus and without leading to reversions. Electron microscopic examination revealed that an ORF III frameshift mutant formed normally structured virions. These results demonstrate that Vap is dispensable for replication in single cells and is not essential for virion morphogenesis. Analysis of inoculated turnip leaves showed that the ORF III frameshift mutant does not cause any detectable local infection. These results are strongly indicative of a role for Vap in virus movement.

scholarly journals Divergent Regulatory Pathways Control A and S Motility in Myxococcus xanthus through FrzE, a CheA-CheY Fusion Protein

2005 ◽  
Vol 187 (5) ◽  
pp. 1716-1723 ◽  
Author(s):  
Yinuo Li ◽  
Víctor H. Bustamante ◽  
Renate Lux ◽  
David Zusman ◽  
Wenyuan Shi
Keyword(s):  
Signal Transduction ◽  
Fusion Protein ◽  
Myxococcus Xanthus ◽  
Point Mutations ◽  
Cell Movement ◽  
Signal Transduction Pathway ◽  
Enteric Bacteria ◽  
Gliding Motility ◽  
Regulatory Pathways

ABSTRACT Myxococcus xanthus moves on solid surfaces by using two gliding motility systems, A motility for individual-cell movement and S motility for coordinated group movements. The frz genes encode chemotaxis homologues that control the cellular reversal frequency of both motility systems. One of the components of the core Frz signal transduction pathway, FrzE, is homologous to both CheA and CheY from the enteric bacteria and is therefore a novel CheA-CheY fusion protein. In this study, we investigated the role of this fusion protein, in particular, the CheY domain (FrzECheY). FrzECheY retains all of the highly conserved residues of the CheY superfamily of response regulators, including Asp709, analogous to phosphoaccepting Asp57 of Escherichia coli CheY. While in-frame deletion of the entire frzE gene caused both motility systems to show a hyporeversal phenotype, in-frame deletion of the FrzECheY domain resulted in divergent phenotypes for the two motility systems: hyperreversals of the A-motility system and hyporeversals of the S-motility system. To further investigate the role of FrzECheY in A and S motility, point mutations were constructed such that the putative phosphoaccepting residue, Asp709, was changed from D to A (and was therefore never subject to phosphorylation) or E (possibly mimicking constitutive phosphorylation). The D709A mutant showed hyperreversals for both motilities, while the D709E mutant showed hyperreversals for A motility and hyporeversal for S motility. These results show that the FrzECheY domain plays a critical signaling role in coordinating A and S motility. On the basis of the phenotypic analyses of the frzE mutants generated in this study, a model is proposed for the divergent signal transduction through FrzE in controlling and coordinating A and S motility in M. xanthus.

scholarly journals Gliding Mutants of Myxococcus xanthuswith High Reversal Frequencies and Small Displacements

1999 ◽  
Vol 181 (8) ◽  
pp. 2593-2601 ◽  
Author(s):  
Alfred M. Spormann ◽  
Dale Kaiser
Keyword(s):  
Single Cell ◽  
Cell Movement ◽  
Gliding Motility ◽  
Wild Type ◽  
Epistasis Analysis ◽  
Type Iv ◽  
Reversal Frequency ◽  
Order Of Magnitude ◽  
Dependent Cell ◽  
Mutant Cells

ABSTRACT Myxococcus xanthus cells move on a solid surface by gliding motility. Several genes required for gliding motility have been identified, including those of the A- and S-motility systems as well as the mgl and frz genes. However, the cellular defects in gliding movement in many of these mutants were unknown. We conducted quantitative, high-resolution single-cell motility assays and found that mutants defective inmglAB or in cglB, an A-motility gene, reversed the direction of gliding at frequencies which were more than 1 order of magnitude higher than that of wild type cells (2.9 min−1for ΔmglAB mutants and 2.7 min−1 forcglB mutants, compared to 0.17 min−1 for wild-type cells). The average gliding speed of ΔmglABmutant cells was 40% of that of wild-type cells (on average 1.9 μm/min for ΔmglAB mutants, compared to 4.4 μm/min for wild-type cells). The mglA-dependent reversals and gliding speeds were dependent on the level of intracellular MglA protein: mglB mutant cells, which contain only 15 to 20% of the wild-type level of MglA protein, glided with an average reversal frequency of about 1.8 min−1 and an average speed of 2.6 μm/min. These values range between those exhibited by wild-type cells and by ΔmglAB mutant cells. Epistasis analysis of frz mutants, which are defective in aggregation and in single-cell reversals, showed that a frzD mutation, but not a frzE mutation, partially suppressed themglA phenotype. In contrast to mgl mutants,cglB mutant cells were able to move with wild-type speeds only when in close proximity to each other. However, under those conditions, these mutant cells were found to glide less often with those speeds. By analyzing double mutants, the high reversing movements and gliding speeds of cglB cells were found to be strictly dependent on type IV pili, encoded by S-motility genes, whereas the high-reversal pattern ofmglAB cells was only partially reduced by apilR mutation. These results suggest that the MglA protein is required for both control of reversal frequency and gliding speed and that in the absence of A motility, type IV pilus-dependent cell movement includes reversals at high frequency. Furthermore, mglAB mutants behave as if they were severely defective in A motility but only partially defective in S motility.

Automated Platform for Cell Selection and Separation Based on Four-Dimensional Motility and Matrix Degradation

2019 ◽  
Author(s):  
Hannah Nowotarski ◽  
Pete Attayek ◽  
Nancy Allbritton
Keyword(s):  
Single Cells ◽  
Cell Movement ◽  
Collagen Scaffold ◽  
Complex Phenotypes ◽  
Biological Phenomena ◽  
Transwell Invasion Assay ◽  
A Cell ◽  
Automated Platform ◽  
Key Steps

<p>Motility and invasion are key steps in the metastatic cascade, enabling cells to move through normal tissue borders into the surrounding stroma. Most available<i> in vitro</i> assays track cell motility or cell invasion but lack the ability to measure both simultaneously and then separate single cells with unique behaviors. In this work, we developed a cell-separation platform capable of tracking cell movement and invasion through an extracellular matrix in space and time. The platform utilized a collagen scaffold with embedded tumor cells overlaid onto a microraft array. Confocal microscopy enabled high resolution (0.4×0.4×3.5 µm voxel) monitoring of cell movement within the scaffolds. Two pancreatic cancer cell lines with known differing invasiveness were characterized on this platform, with median motilities of 14±6 mm and 10±4 mm over 48 h. Within the same cell line, cells demonstrated highly variable motility, with a range of XYZ movement from 144 mm to 2 mm over 24 h. The ten lowest and highest motility cells, with median movements of 33±11 mm and 3±1 mm, respectively, were separated and sub-cultured. After 6 weeks of culture, the cell populations were assayed on a Transwell invasion assay and 227±56 cells were invasive in the high motility population while only 48±10 cells were invasive in the low motility population, indicating that the resulting offspring possessed a motility phenotype reflective of the parental cells. This work demonstrates the feasibility of sorting single cells based on complex phenotypes along with the capability to further probe those cells and explore biological phenomena. </p>

Automated Platform for Cell Selection and Separation Based on Four-Dimensional Motility and Matrix Degradation

2019 ◽  
Author(s):  
Hannah Nowotarski ◽  
Pete Attayek ◽  
Nancy Allbritton
Keyword(s):  
Single Cells ◽  
Cell Movement ◽  
Collagen Scaffold ◽  
Complex Phenotypes ◽  
Biological Phenomena ◽  
Transwell Invasion Assay ◽  
A Cell ◽  
Automated Platform ◽  
Key Steps

<p>Motility and invasion are key steps in the metastatic cascade, enabling cells to move through normal tissue borders into the surrounding stroma. Most available<i> in vitro</i> assays track cell motility or cell invasion but lack the ability to measure both simultaneously and then separate single cells with unique behaviors. In this work, we developed a cell-separation platform capable of tracking cell movement and invasion through an extracellular matrix in space and time. The platform utilized a collagen scaffold with embedded tumor cells overlaid onto a microraft array. Confocal microscopy enabled high resolution (0.4×0.4×3.5 µm voxel) monitoring of cell movement within the scaffolds. Two pancreatic cancer cell lines with known differing invasiveness were characterized on this platform, with median motilities of 14±6 mm and 10±4 mm over 48 h. Within the same cell line, cells demonstrated highly variable motility, with a range of XYZ movement from 144 mm to 2 mm over 24 h. The ten lowest and highest motility cells, with median movements of 33±11 mm and 3±1 mm, respectively, were separated and sub-cultured. After 6 weeks of culture, the cell populations were assayed on a Transwell invasion assay and 227±56 cells were invasive in the high motility population while only 48±10 cells were invasive in the low motility population, indicating that the resulting offspring possessed a motility phenotype reflective of the parental cells. This work demonstrates the feasibility of sorting single cells based on complex phenotypes along with the capability to further probe those cells and explore biological phenomena. </p>

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