scholarly journals Increase in Growth Cone Size Correlates with Decrease in Neurite Growth Rate

2016 ◽  
Vol 2016 ◽  
pp. 1-13 ◽  
Author(s):  
Yuan Ren ◽  
Daniel M. Suter
Keyword(s):  
Cell Culture ◽  
Growth Rate ◽  
Growth Cone ◽  
Cell Biology ◽  
Inverse Correlation ◽  
Neurite Growth ◽  
Growth Cones ◽  
Average Growth ◽  
Cellular Analysis ◽  
Large Growth

Several important discoveries in growth cone cell biology were made possible by the use of growth cones derived from culturedAplysiabag cell neurons, including the characterization of the organization and dynamics of the cytoskeleton. The majority of theseAplysiastudies focused on large growth cones induced by poly-L-lysine substrates at early stages in cell culture. Under these conditions, the growth cones are in a steady state with very little net advancement. Here, we offer a comprehensive cellular analysis of the motile behavior ofAplysiagrowth cones in culture beyond this pausing state. We found that average growth cone size decreased with cell culture time whereas average growth rate increased. This inverse correlation of growth rate and growth cone size was due to the occurrence of large growth cones with a peripheral domain larger than 100 μm2. The large pausing growth cones had central domains that were less consistently aligned with the direction of growth and could be converted into smaller, faster-growing growth cones by addition of a three-dimensional collagen gel. We conclude that the significant lateral expansion of lamellipodia and filopodia as observed during these culture conditions has a negative effect on neurite growth.

scholarly journals Delayed Retraction of Filopodia in Gelsolin Null Mice

1997 ◽  
Vol 138 (6) ◽  
pp. 1279-1287 ◽  
Author(s):  
Mei Lu ◽  
Walter Witke ◽  
David J. Kwiatkowski ◽  
Kenneth S. Kosik
Keyword(s):  
Growth Cone ◽  
Hippocampal Neurons ◽  
Neurite Growth ◽  
Time Lapse ◽  
Growth Cones ◽  
Wild Type ◽  
Dynamic Studies ◽  
Shape Changes ◽  
Time Lapse Video ◽  
Cultured Hippocampal Neurons

Growth cones extend dynamic protrusions called filopodia and lamellipodia as exploratory probes that signal the direction of neurite growth. Gelsolin, as an actin filament-severing protein, may serve an important role in the rapid shape changes associated with growth cone structures. In wild-type (wt) hippocampal neurons, antibodies against gelsolin labeled the neurite shaft and growth cone. The behavior of filopodia in cultured hippocampal neurons from embryonic day 17 wt and gelsolin null (Gsn−) mice (Witke, W., A.H. Sharpe, J.H. Hartwig, T. Azuma, T.P. Stossel, and D.J. Kwiatkowski. 1995. Cell. 81:41–51.) was recorded with time-lapse video microscopy. The number of filopodia along the neurites was significantly greater in Gsn− mice and gave the neurites a studded appearance. Dynamic studies suggested that most of these filopodia were formed from the region of the growth cone and remained as protrusions from the newly consolidated shaft after the growth cone advanced. Histories of individual filopodia in Gsn− mice revealed elongation rates that did not differ from controls but an impaired retraction phase that probably accounted for the increased number of filopodia long the neutrite shaft. Gelsolin appears to function in the initiation of filopodial retraction and in its smooth progression.

scholarly journals Computational modeling of neurons: intensity-duration relationship of extracellular electrical stimulation for changes in intracellular calcium

2016 ◽  
Vol 115 (1) ◽  
pp. 602-616 ◽  
Author(s):  
Robert D. Adams ◽  
Rebecca K. Willits ◽  
Amy B. Harkins
Keyword(s):  
Electrical Stimulation ◽  
Intracellular Calcium ◽  
Growth Cone ◽  
Pulse Train ◽  
Neurite Growth ◽  
Growth Cones ◽  
Train Duration ◽  
Voltage Dependent ◽  
Duration Relationship ◽  
Relationship Of

In many instances of extensive nerve damage, the injured nerve never adequately heals, leaving lack of nerve function. Electrical stimulation (ES) has been shown to increase the rate and orient the direction of neurite growth, and is a promising therapy. However, the mechanism in which ES affects neuronal growth is not understood, making it difficult to compare existing ES protocols or to design and optimize new protocols. We hypothesize that ES acts by elevating intracellular calcium concentration ([Ca2+]i) via opening voltage-dependent Ca2+ channels (VDCCs). In this work, we have created a computer model to estimate the ES Ca2+ relationship. Using COMSOL Multiphysics, we modeled a small dorsal root ganglion (DRG) neuron that includes one Na+ channel, two K+ channels, and three VDCCs to estimate [Ca2+]i in the soma and growth cone. As expected, the results show that an ES that generates action potentials (APs) can efficiently raise the [Ca2+]i of neurons. More interestingly, our simulation results show that sub-AP ES can efficiently raise neuronal [Ca2+]i and that specific high-voltage ES can preferentially raise [Ca2+]i in the growth cone. The intensities and durations of ES on modeled growth cone calcium rise are consistent with directionality and orientation of growth cones experimentally shown by others. Finally, this model provides a basis to design experimental ES pulse parameters, including duration, intensity, pulse-train frequency, and pulse-train duration to efficiently raise [Ca2+]i in neuronal somas or growth cones.

scholarly journals Mitochondrial Dynamics Regulate Growth Cone Motility, Guidance, and Neurite Growth Rate in Perinatal Retinal Ganglion Cells In Vitro

2012 ◽  
Vol 53 (11) ◽  
pp. 7402 ◽  
Author(s):  
Michael B. Steketee ◽  
Stavros N. Moysidis ◽  
Jessica E. Weinstein ◽  
Alex Kreymerman ◽  
Jose P. Silva ◽  
...  
Keyword(s):  
Growth Rate ◽  
Retinal Ganglion Cells ◽  
Growth Cone ◽  
Ganglion Cells ◽  
Mitochondrial Dynamics ◽  
Neurite Growth ◽  
Retinal Ganglion

scholarly journals Differences in the organization of actin in the growth cones compared with the neurites of cultured neurons from chick embryos.

1983 ◽  
Vol 97 (4) ◽  
pp. 963-973 ◽  
Author(s):  
P C Letourneau
Keyword(s):  
Growth Cone ◽  
Actin Filaments ◽  
Electron Microscopic Observation ◽  
Neurite Growth ◽  
Growth Cones ◽  
Chick Embryos ◽  
Heavy Meromyosin ◽  
Electron Microscopic ◽  
Cytochemical Localization ◽  
Triton X

Sensory neurons from chick embryos were cultured on substrata that support neurite growth, and were fixed and prepared for both cytochemical localization of actin and electron microscopic observation of actin filaments in whole-mounted specimens. Samples of cells were treated with the detergent Triton X-100 before, during, or after fixation with glutaraldehyde to determine the organization of actin in simpler preparations of extracted cytoskeletons. Antibodies to actin and a fluorescent derivative of phallacidin bound strongly to the leading margins of growth cones, but in neurites the binding of these markers for actin was very weak. This was true in all cases of Triton X-100 treatment, even when cells were extracted for 4 min before fixation. In whole-mounted cytoskeletons there were bundles and networks of 6-7-nm filaments in leading edges of growth cones but very few 6-7-n filaments were present among the microtubules and neurofilaments in the cytoskeletons of neurites. These filaments, which are prominent in growth cones, were identified as actin because they were stabilized against detergent extraction by the presence of phallacidin or the heavy meromyosin and S1 fragments of myosin. In addition, heavy meromyosin and S1 decorated these filaments as expected for binding to F-actin. Microtubules extended into growth cone margins and terminated within the network of actin filaments and bundles. Interactions between microtubule ends and these actin filaments may account for the frequently observed alignment of microtubules with filopodia at the growth cone margins.

The origin of neuronal polarization: a model of axon formation

1996 ◽  
Vol 351 (1344) ◽  
pp. 1147-1156 ◽  
Keyword(s):  
Growth Rate ◽  
Rapid Growth ◽  
Physical Mechanism ◽  
Neurite Growth ◽  
Growth Cones ◽  
The Other ◽  
Individual Growth ◽  
Winner Take All ◽  
Neuronal Polarization ◽  
Take All

During development, most neurons become polarized when one neurite, generally the longest, becomes the axon and the other neurites become dendrites. The physical mechanism responsible for such lengthrelated differentiation has not been established. Here, we present a model of neuronal polarization based upon the existence of a ‘determinant chemical’ whose concentration at the neurite tips influences the growth rate of the neurite. Over an extended parameter range, the equations describing the formation, transport, and consumption of this chemical and the resulting neurite growth undergo a winner-take-all instability, yielding rapid growth of one neurite (the axon) and diminished growth of all others. The behaviour of this model agrees well with the results of axotomy experiments and experiments in which growth-modulating substances are applied to individual growth cones. Possible candidates for the determinant chemical are discussed, and further experiments are proposed to test the model.

scholarly journals A cytomechanical investigation of neurite growth on different culture surfaces.

1992 ◽  
Vol 118 (3) ◽  
pp. 655-661 ◽  
Author(s):  
P Lamoureux ◽  
J Zheng ◽  
R E Buxbaum ◽  
S R Heidemann
Keyword(s):  
Sensory Neurons ◽  
Growth Cone ◽  
Rate Sensitivity ◽  
Neurite Growth ◽  
Growth Cones ◽  
Elongation Rate ◽  
Collagen Type Iv ◽  
Mean Values ◽  
Axonal Elongation ◽  
Applied Tension

We have examined the relationship between tension, an intrinsic stimulator of axonal elongation, and the culture substrate, an extrinsic regulator of axonal elongation. Chick sensory neurons were cultured on three substrata: (a) plain tissue culture plastic; (b) plastic treated with collagen type IV; and (c) plastic treated with laminin. Calibrated glass needles were used to increase the tension loads on growing neurites. We found that growth cones on all substrata failed to detach when subjected to two to threefold and in some cases 5-10-fold greater tensions than their self-imposed rest tension. We conclude that adhesion to the substrate does not limit the tension exerted by growth cones. These data argue against a "tug-of-war" model for substrate-mediated guidance of growth cones. Neurite elongation was experimentally induced by towing neurites with a force-calibrated glass needle. On all substrata, towed elongation rate was proportional to applied tension above a threshold tension. The proportionality between elongation rate and tension can be regarded as the growth sensitivity of the neurite to tension, i.e., its growth rate per unit tension. On this basis, towed growth on all substrata can be described by the simple linear equation: elongation rate = sensitivity x (applied tension - tension threshold) The numerical values of tension thresholds and neurite sensitivities varied widely among different neurites. On all substrata, thresholds varied from near zero to greater than 200 mudynes, with some tendency for thresholds to cluster between 100 and 150 mudynes. Similarly, the tension sensitivity of neurites varied between 0.5 and 5.0 microns/h/mudyne. The lack of significant differences among sensitivity or threshold values on the various substrata suggest to use that the substratum does not affect the internal "set points" of the neurite for its response to tension. The growth cone of chick sensory neurons is known to pull on its neurite. The simplest cytomechanical model would assume that both growth cone-mediated elongation and towed growth are identical as far as tension input and elongation rate are concerned. We used the equation above and mean values for thresholds and sensitivity from towing experiments to predict the mean growth cone-mediated elongation rate based on mean rest tensions. These predictions are consistent with the observed mean values.

scholarly journals Axonal outgrowth of cultured neurons is not limited by growth cone competition

1998 ◽  
Vol 111 (21) ◽  
pp. 3245-3252
Author(s):  
P. Lamoureux ◽  
R.E. Buxbaum ◽  
S.R. Heidemann
Keyword(s):  
Growth Cone ◽  
Single Neuron ◽  
High Capacity ◽  
Normal Growth ◽  
Growth Cones ◽  
Individual Growth ◽  
Discrete Events ◽  
Poor Growth ◽  
Average Growth ◽  
Axonal Elongation

We have examined the question of scarcity-driven competition for outgrowth among growth cones of a single neuron. We measured spontaneous neurite elongation rates from 85 hours of videotape of the arbors of 31 chick sensory neurons in culture. These rate measurements were analyzed in ten minute periods that allowed cell bodies to be classified as to the number of their growth cones and the elongation to be analyzed as a series of discrete events. Comparing periods in which neurons maintained simple bipolar morphology we find no temporal competition between the two growth cones. That is, periods of above-average growth by one growth cone are not compensated by below-average growth during the same period by its sibling growth cone. Analyzing all outgrowth from a neuron based on its number of growth cones shows that net elongation rate from a single cell body is a linear function of the number of growth cones from 1 to 11. These observations suggest that growth cones behave independently and are not limited by availability of structural precursors. A surplus pool of structural precursors available for normal growth is also indicated by the high capacity for growth from single neurites when experimentally stimulated by mechanical tension. In addition, towing one or more neurites at above average rates does not cause any decline in simultaneous growth cone-mediated outgrowth from a single neuron compared to the 2–3 hour period prior to experimentally induced elongation. This high capacity for growth combined with the often observed, intermittant growth behavior of individual growth cones suggests that neurite outgrowth is intrinsically limited primarily by poor growth cone ‘performance,’ not scarcity-driven competition. We postulate that growth cones are poor ‘tractors,’ exerting too little tension to exploit the available capacity for axonal elongation.

SUBSTITUSI FERMENTASI BUNGKIL KELAPA SAWIT DALAM PAKAN BUATAN TERHADAP PERTUMBUHAN DAN KELANGSUNGAN HIDUP BENIH IKAN GURAMI (OSPHRONEMUS GOURAMY)

2016 ◽  
Vol 4 (1) ◽  
Author(s):  
Farida . ◽  
Eka Indah Raharjo ◽  
Arnis Maylinda Sari
Keyword(s):  
Growth Rate ◽  
Palm Oil ◽  
Palm Kernel ◽  
Specific Weight ◽  
Feed Conversion ◽  
Daily Growth Rate ◽  
Daily Growth ◽  
Average Growth ◽  
Fermentation Residue ◽  
Average Average

ABSTRAKPenelitian bertujuan untuk mengetahui penggunaan fermentasi bungkil kelapa sawit dalam pakan buatan.Penelitian menggunakan Rancangan Acak Lengkap (RAL) yang terdiri dari 4 perlakuan 3 ulangan.Susunan perlakuan adalah Perlakuan A : bungkil kelapa sawit 12%, Perlakuan B : fermentasi bungkil kelapa sawit 15%, Perlakuan C : fermentasi bungkil kelapa sawit 18%, Perlakuan D : fermentasi bungkil kelapa sawit 21%. Penelitian ini dilakukan selama 60 hari untuk mengetahui laju pertumbuhan spesifikberat, laju pertumbuhan harianpanjang, konversi pakan, kelangsungan hidup dan kualitas air sebagai penunjang.Hasil penelitian menunjukkan pemberian pakan buatan dengan fermentasi bungkil kelapa sawit menghasilkan respon yang baik terhadap pertumbuhan ikan gurami. Pemberian pakan buatan dengan fermentasi bungkil kelapa sawit 18% (perlakuan C), memberikan hasil terbaik dengan laju pertumbuhan dengan rata – rata laju pertumbuhan spesifik berat 1.502%, laju pertumbuhan harian panjang 4.06%, nilai konversi pakan rata – rata 3.48 dan kelangsungan hidup rata – rata 90%.Kata Kunci : Fermentasi Bungkil Kelapa Sawit, Ikan Gurami, Laju PertumbuhanThe study aims to determine the use of fermentation residue oil palm in artificial feed .Research using a completely randomized design ( CRD ), which consists of 4 treatment three replications.The composition of the treatment is the treatment  A : 12 % of palm oil cake , Treatment B : fermented palm oil cake 15 % , Treatment C : fermented palm oil cake 18 % , Treatment D : fermentation residue palm oil 21 %.This research was conducted for 60 days to determine the specific growth rate of heavy , long daily growth rate , feed conversion , survival and quality of water as a supporter.The results showed the artificial feeding with fermented palm cake to produce a good response to the growth of carp.Feeding artificially by fermentation cake palm oil 18 % ( treatment C ) , gives the best results with a growth rate with the average - average growth rate of the specific weight of 1.502 % daily growth rate long- 4:06 % , the value of feed conversion average - average 3:48 and median survival - average of 90 % .Keywords : Fermentation Palm Kernel Oil, Fish carp, Growth Rate

The United States as the Trade Partner of Poland in te Context of the Transatlantic Trade and Investment Partnership (TTIP)

2014 ◽  
Vol 9 (3) ◽  
pp. 201-213
Author(s):  
Renata Marks-Bielska ◽  
Wiesława Lizińska ◽  
Izabela Serocka
Keyword(s):  
Growth Rate ◽  
Foreign Trade ◽  
The United States ◽  
Average Growth ◽  
Transatlantic Trade ◽  
Central Statistical ◽  
The Usa ◽  
Central Statistical Office ◽  
Trade Partner ◽  
Structure Of Trade

Evaluation of the importance of the USA as the trade partner of Poland is the main objective of the paper, based on the changes in the value of trade during the years 2000-2012 and changes in the structure of trade during the years 2008-2012. The data from the Statistical Yearbooks of Foreign Trade published by the Central Statistical Office was used. The potential for foreign trade growth was illustrated using the simplified analysis based on the gravity model of foreign trade concept. Gradually increasing value of Polish trade with the USA (the average growth rate 9.8%, EU-15 countries 13.1%). Polish exports are characterised by a higher than imports growth rate (USA - exports growth by 12.5%, imports 9.2%, EU-15 - exports 15.1%, imports 11.6%). Trade is strongly dominated by position of one group of products (over 30% share in both exports and imports). The potential of trade is poorly exploited currently. Trade was focused mainly on the countries situated in the close neighbourhood (mainly the EU countries with the domination of Germany).

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