The Phototactic Sensorimotor Mechanism of the Unicellular Alga Euglena Gracilis. An Application to the Evolutionary Study of Vision

Perception ◽  
1997 ◽  
Vol 26 (1_suppl) ◽  
pp. 187-187
Author(s):  
E M Insinna
Keyword(s):  
Cell Motility ◽  
Euglena Gracilis ◽  
Intracellular Transport ◽  
Sensory Cells ◽  
Unicellular Alga ◽  
Unicellular Organism ◽  
Ciliary Beating ◽  
Basic Functions ◽  
Dynamical Function ◽  
Phototactic Behaviour

Our understanding of even basic functions of microtubules (MT) such as intracellular transport and ciliary beating, including their role in sensory cells and nerve cells, is still incomplete. For example, vertebrate photoreceptors contain a cilium whose possible dynamical function is still unknown. A new model of microtubular dynamics, developed by me together with P Zaborski and J Tuszynski [Insinna et al, 1996 BioSystems39(3) 187 – 226], is capable of accounting for most of the phenomena associated with cell motility. Additionally, it sheds new light not only on the phototactic behaviour of the Protozoan Euglena gracilis but also on some possible evolutionary steps leading from primitive sensory organs to more complex ones such as the photoreceptors of vertebrates. Euglena displays simple perceptive functions (phototaxis) based on a primitive photoreceptor. This unicellular organism offers a unique possibility to study the function of MT in a simple form of vision. The model is based on classical nonlinear physics and suggests a dynamical role for MT in vertebrate photoreceptors. I am convinced that a better understanding of photoreceptor dynamics requires knowledge of the evolutionary steps leading to their development.

scholarly journals PACRG and FAP20 form the inner junction of axonemal doublet microtubules and regulate ciliary motility

2019 ◽  
Vol 30 (15) ◽  
pp. 1805-1816 ◽  
Author(s):  
Erin E. Dymek ◽  
Jianfeng Lin ◽  
Gang Fu ◽  
Mary E. Porter ◽  
Daniela Nicastro ◽  
...  
Keyword(s):  
Cell Motility ◽  
Electron Tomography ◽  
Structural Studies ◽  
Ciliary Beating ◽  
Ciliary Motility ◽  
Functional Studies ◽  
Cryo Electron Tomography ◽  
Motile Cilia

We previously demonstrated that PACRG plays a role in regulating dynein-driven microtubule sliding in motile cilia. To expand our understanding of the role of PACRG in ciliary assembly and motility, we used a combination of functional and structural studies, including newly identified Chlamydomonas pacrg mutants. Using cryo-electron tomography we show that PACRG and FAP20 form the inner junction between the A- and B-tubule along the length of all nine ciliary doublet microtubules. The lack of PACRG and FAP20 also results in reduced assembly of inner-arm dynein IDA b and the beak-MIP structures. In addition, our functional studies reveal that loss of PACRG and/or FAP20 causes severe cell motility defects and reduced in vitro microtubule sliding velocities. Interestingly, the addition of exogenous PACRG and/or FAP20 protein to isolated mutant axonemes restores microtubule sliding velocities, but not ciliary beating. Taken together, these studies show that PACRG and FAP20 comprise the inner junction bridge that serves as a hub for both directly modulating dynein-driven microtubule sliding, as well as for the assembly of additional ciliary components that play essential roles in generating coordinated ciliary beating.

scholarly journals When Unity Is Strength: The Strategies Used by Chlamydomonas to Survive Environmental Stresses

Cells ◽  
2019 ◽  
Vol 8 (11) ◽  
pp. 1307 ◽  
Author(s):  
Félix de Carpentier ◽  
Stéphane D. Lemaire ◽  
Antoine Danon
Keyword(s):  
Environmental Conditions ◽  
Wide Spectrum ◽  
Optimal Growth ◽  
Growth Conditions ◽  
Mild Stress ◽  
Unicellular Alga ◽  
Unicellular Organism ◽  
Unicellular Green Alga ◽  
Scientific Fields ◽  
Do So

The unicellular green alga Chlamydomonas reinhardtii is a valuable model system to study a wide spectrum of scientific fields, including responses to environmental conditions. Most studies are performed under optimal growth conditions or under mild stress. However, when environmental conditions become harsher, the behavior of this unicellular alga is less well known. In this review we will show that despite being a unicellular organism, Chlamydomonas can survive very severe environmental conditions. To do so, and depending on the intensity of the stress, the strategies used by Chlamydomonas can range from acclimation to the formation of multicellular structures, or involve programmed cell death.

scholarly journals Oscillation of ADP-ribosyl cyclase activity during the cell cycle and function of cyclic ADP-ribose in a unicellular organism, Euglena gracilis

FEBS Letters ◽  
1997 ◽  
Vol 405 (1) ◽  
pp. 104-106 ◽  
Author(s):  
Wataru Masuda ◽  
Shigeo Takenaka ◽  
Kiyoshi Inageda ◽  
Hiroshi Nishina ◽  
Katsunobu Takahashi ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Euglena Gracilis ◽  
Cyclase Activity ◽  
Unicellular Organism ◽  
Adp Ribosyl Cyclase ◽  
Cyclic Adp Ribose ◽  
And Function

Cell cycle dependent ADP-ribosylation of a unicellular organism, Euglena gracilis Z

1995 ◽  
Vol 111 (2) ◽  
pp. 277-282
Author(s):  
Shigeo Takenaka ◽  
Junko Inagaki ◽  
Shingo Tsuyama ◽  
Kazutaka Miyatake ◽  
Yoshihisa Nakano
Keyword(s):  
Cell Cycle ◽  
Euglena Gracilis ◽  
Unicellular Organism ◽  
Adp Ribosylation ◽  
Cycle Dependent ◽  
Euglena Gracilis Z

Single Cell Traffic of Swimming Green Paramecia on Microchips with Micro-Flow Channels Fabricated by Micro-Casting

2014 ◽  
Vol 875-877 ◽  
pp. 2224-2228
Author(s):  
Kohei Otsuka ◽  
Sayaka Maruta ◽  
Atsuko Noriyasu ◽  
Kohji Nakazawa ◽  
Tomonori Kawano
Keyword(s):  
Methyl Methacrylate ◽  
Single Cell ◽  
Living Cells ◽  
Micro Milling ◽  
Sensory Cells ◽  
Unicellular Organism ◽  
Micro Electro Mechanical Systems ◽  
Flow Channels ◽  
Micro Flow

Members of Paramecium species are often referred to as “swimming neurons or sensory cells” applicable to micro-biorobotics or BioMEMS (biological micro-electro-mechanical systems). Paramecium bursaria known as green paramecia is an unicellular organism that lives widely in fresh water environments such as rivers and ponds. Recent studies have suggested that in vivo cellular robotics using the living cells of green paramecia as micro-machines controllable under electrical, optical and magnetic signals, has a variety of engineering applications such as transportation of micro-sized particles (ingested within the cells) in the capillary systems. In the present study, we aimed to test if the swimming environment of green paramecia can be implementable on microchips. For this purpose, the series of microchips were prepared for cellular swimming platform for green paramecia through fabrication of poly(methyl methacrylate) master plates using the programmable micro-milling system followed by polydimethylsiloxane-based micro-casting. Finally, microchips equipped with optimally sized micro-flow channels for allowing the single cell traffic by swimming green paramecia were successfully prepared, and thus further studies for application of green paramecium cells in BioMEMS are encouraged.

scholarly journals Multifaceted Function of Myosin-18, an Unconventional Class of the Myosin Superfamily

2021 ◽  
Vol 9 ◽  
Author(s):  
Zhaohui Ouyang ◽  
Shuangshuang Zhao ◽  
Su Yao ◽  
Jing Wang ◽  
Yanqin Cui ◽  
...  
Keyword(s):  
Cell Motility ◽  
Mammalian Cells ◽  
Intracellular Transport ◽  
Molecular Mechanisms ◽  
Muscle Development ◽  
Focal Adhesions ◽  
Transport Processes ◽  
Cytoskeletal Proteins ◽  
Future Research ◽  
Research Perspectives

Myosin is a diverse superfamily of motor proteins responsible for actin-based motility and contractility in eukaryotic cells. Myosin-18 family, including myosin-18A and myosin-18B, belongs to an unconventional class of myosin, which lacks ATPase motor activity, and the investigations on their functions and molecular mechanisms in vertebrate development and diseases have just been initiated in recent years. Myosin-18A is ubiquitously expressed in mammalian cells, whereas myosin-18B shows strong enrichment in striated muscles. Myosin-18 family is important for cell motility, sarcomere formation, and mechanosensing, mostly by interacting with other cytoskeletal proteins and cellular apparatus. Myosin-18A participates in several intracellular transport processes, such as Golgi trafficking, and has multiple roles in focal adhesions, stress fibers, and lamellipodia formation. Myosin-18B, on the other hand, participates in actomyosin alignment and sarcomere assembly, thus relating to cell migration and muscle contractility. Mutations of either Myo18a or Myo18b cause cardiac developmental defects in mouse, emphasizing their crucial role in muscle development and cardiac diseases. In this review, we revisit the discovery history of myosin-18s and summarize the evolving understanding of the molecular functions of myosin-18A and myosin-18B, with an emphasis on their separate yet closely related functions in cell motility and contraction. Moreover, we discuss the diseases tightly associated with myosin-18s, especially cardiovascular defects and cancer, as well as highlight the unanswered questions and potential future research perspectives on myosin-18s.

Organization of the Pellicle and the Muciferous Glands in Euglena Gracilis

1970 ◽  
Vol 28 ◽  
pp. 104-105
Author(s):  
Hilton H. Mollenhauer ◽  
W. Evans
Keyword(s):  
Plasma Membrane ◽  
Euglena Gracilis ◽  
Complex Forms ◽  
Secondary Periodicity

The pellicular structure of Euglena gracilis consists of a series of relatively rigid strips (Fig. 1) composed of ridges and grooves which are helically oriented along the cell and which fuse together into a common junction at either end of the cell. The strips are predominantly protein and consist in part of a series of fibers about 50 Å in diameter spaced about 85 Å apart and with a secondary periodicity of about 450 Å. Microtubules are also present below each strip (Fig. 1) and are often considered as part of the pellicular complex. In addition, there may be another fibrous component near the base of the pellicle which has not yet been very well defined.The pellicular complex lies underneath the plasma membrane and entirely within the cell (Fig. 1). Each strip of the complex forms an overlapping junction with the adjacent strip along one side of each groove (Fig. 1), in such a way that a certain amount of sideways movement is possible between one strip and the next.

A Study on the Fine Structure of the Lateral Line Organ of the Sea Eel

1973 ◽  
Vol 31 ◽  
pp. 648-649
Author(s):  
K. Hama
Keyword(s):  
Fine Structure ◽  
Electron Microscope ◽  
Lateral Line ◽  
Low Frequency ◽  
Sensory Cells ◽  
Apical Surface ◽  
Voltage Electron ◽  
Sensory Epithelia ◽  
Low Frequency Vibration ◽  
Transmission Electron

The lateral line organs of the sea eel consist of canal and pit organs which are different in function. The former is a low frequency vibration detector whereas the latter functions as an ion receptor as well as a mechano receptor.The fine structure of the sensory epithelia of both organs were studied by means of ordinary transmission electron microscope, high voltage electron microscope and of surface scanning electron microscope.The sensory cells of the canal organ are polarized in front-caudal direction and those of the pit organ are polarized in dorso-ventral direction. The sensory epithelia of both organs have thinner surface coats compared to the surrounding ordinary epithelial cells, which have very thick fuzzy coatings on the apical surface.

Changes Occur in Plasma Membrane Turnover when K562 Leukemia Cells are Induced to Differentiate

1982 ◽  
Vol 40 ◽  
pp. 286-287
Author(s):  
L. M. Marshall
Keyword(s):  
Plasma Membrane ◽  
Membrane Proteins ◽  
Intracellular Transport ◽  
Parent Cell ◽  
Membrane Turnover ◽  
Coated Pits ◽  
Surface Distribution ◽  
Specific Proteins ◽  
Erythroleukemic Cell ◽  
Specific Membrane

A human erythroleukemic cell line, metabolically blocked in a late stage of erythropoiesis, becomes capable of differentiation along the normal pathway when grown in the presence of hemin. This process is characterized by hemoglobin synthesis followed by rearrangement of the plasma membrane proteins and culminates in asymmetrical cytokinesis in the absence of nuclear division. A reticulocyte-like cell buds from the nucleus-containing parent cell after erythrocyte specific membrane proteins have been sequestered into its membrane. In this process the parent cell faces two obstacles. First, to organize its erythrocyte specific proteins at one pole of the cell for inclusion in the reticulocyte; second, to reduce or abolish membrane protein turnover since hemoglobin is virtually the only protein being synthesized at this stage. A means of achieving redistribution and cessation of turnover could involve movement of membrane proteins by a directional lipid flow. Generation of a lipid flow towards one pole and accumulation of erythrocyte-specific membrane proteins could be achieved by clathrin coated pits which are implicated in membrane endocytosis, intracellular transport and turnover. In non-differentiating cells, membrane proteins are turned over and are random in surface distribution. If, however, the erythrocyte specific proteins in differentiating cells were excluded from endocytosing coated pits, not only would their turnover cease, but they would also tend to drift towards and collect at the site of endocytosis. This hypothesis requires that different protein species are endocytosed by the coated vesicles in non-differentiating than by differentiating cells.

Fluorocitrate Neural Dystrophy of the Guinea Pig Cochlea

1975 ◽  
Vol 33 ◽  
pp. 368-369
Author(s):  
G.J. Spector ◽  
C.D. Carr ◽  
I. Kaufman Arenberg ◽  
R.H. Maisel
Keyword(s):  
Hearing Loss ◽  
Hair Cells ◽  
Sodium Phosphate ◽  
Sensory Cells ◽  
Barium Salt ◽  
Perfusion Medium ◽  
Cochlear Hair Cells ◽  
Neural Degeneration ◽  
Sodium Phosphate Buffer ◽  
Cochlear Neurons

All studies on primary neural degeneration in the cochlea have evaluated the end stages of degeneration or the indiscriminate destruction of both sensory cells and cochlear neurons. We have developed a model which selectively simulates the dystrophic changes denoting cochlear neural degeneration while sparing the cochlear hair cells. Such a model can be used to define more precisely the mechanism of presbycusis or the hearing loss in aging man.Twenty-two pigmented guinea pigs (200-250 gm) were perfused by the perilymphatic route as live preparations using fluorocitrate in various concentrations (15-250 ug/cc) and at different incubation times (5-150 minutes). The barium salt of DL fluorocitrate, (C6H4O7F)2Ba3, was reacted with 1.0N sulfuric acid to precipitate the barium as a sulfate. The perfusion medium was prepared, just prior to use, as follows: sodium phosphate buffer 0.2M, pH 7.4 = 9cc; fluorocitrate = 15-200 mg/cc; and sucrose = 0.2M.

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