Responses of growth cones to changes in osmolality of the surrounding medium

1991 ◽  
Vol 98 (4) ◽  
pp. 507-515
Author(s):  
D. Bray ◽  
N.P. Money ◽  
F.M. Harold ◽  
J.R. Bamburg
Keyword(s):  
Hydrostatic Pressure ◽  
Growth Cone ◽  
Culture Medium ◽  
Vapor Pressure Deficit ◽  
Surrounding Medium ◽  
Culture Fluid ◽  
Short Term ◽  
Area Reduction ◽  
Osmotic Response ◽  
Upper Limits

The possible involvement of osmotically generated hydrostatic pressure in driving actin-rich extensions of the cell surface was examined using cultures of chick neurons. Estimation of the excess internal osmotic pressure of chick neural tissue by vapor pressure deficit osmometry, and of the excess internal hydrostatic pressure in cultured chick neurons using a calibrated pressure pipette, gave upper limits of 10 mosM and 0.1 atmosphere (1 atmosphere = 101325 Pa), respectively. Increases in the osmolality of the medium surrounding cultured neurons by addition of sucrose, mannitol or polyethylene glycol by amounts that should eliminate any internal pressure not only failed to arrest the growth of filopodia but caused them to increase in length up to twofold in 3–5 min. Lamellipodia remained unchanged following hyperosmotic shifts of 20 mosM, but higher levels caused a small decrease in area. Reduction of osmolality by the addition of water to the culture fluid down to 50% of its normal value failed to show any detectable change in either filopodial length or lamellipodia area. These observations argue against an osmotic mechanism for growth cone extension and show that the growth of filopodia, in particular, is unlikely to be driven by osmotically generated hydrostatic pressure. In contrast to the short-term effects on growth cone morphology, the slower elongation of the neuritic cylinder showed a consistent osmotic response. Growth rates were reduced following addition of osmolytes and increased in rate (as much as sixfold) following addition of water to the culture medium.(ABSTRACT TRUNCATED AT 250 WORDS)

Proliferation and agglutinability of primary and transformed human epithelial cells in culture

1976 ◽  
Vol 21 (3) ◽  
pp. 553-561
Author(s):  
M.A. Ricard ◽  
R.J. Hay
Keyword(s):  
Culture Medium ◽  
Monolayer Culture ◽  
Primary Cultures ◽  
Short Term ◽  
Chloromethyl Ketone ◽  
Normal Populations ◽  
Short Term Exposure ◽  
Cell Strains ◽  
Human Placentae

Primary epithelial populations (HAM) were obtained by dissociation of the amniotic membrane stripped from human placentae. Agglutinability of cells from such normal populations and of cells from the transformed epithelial line WISH was then compared using concavanalin A as mediator. Extensive similar studies have previously been reported with cell strains isolated from other species. Freshly dissociated HAM cells from primary cultures agglutinated much less readily than did cells from WISH populations. Furthermore, the former exhibited a drastic decline in agglutinability as a function of time in suspension culture after trypsinization. Short-term exposure (60 h) of HAM cells in monolayer culture to 5-bromodeoxyuridine (BrdU) elicited heightened agglutinability detectable through 22 days in vitro. Addition of the protease inhibitors n-tosyl-L-lysyl-chloromethyl ketone (TLCK) or p-tosyl-L-arginine-methyl ester (TAME) to the culture medium inhibited proliferation of the WISH line by 40–50% while effecting only a 10–15% inhibition of HAM cells. These results also confirm data with other cell species indicating that high proteolytic activity at the surface of transformed cells may be related to the rapid proliferation rate.

scholarly journals CLONAL VARIATION IN PARAMECIUM. I. PERSISTENT UNSTABLE CLONES

Genetics ◽  
1972 ◽  
Vol 72 (1) ◽  
pp. 17-33
Author(s):  
Irving Finger ◽  
Carol Heller ◽  
Linda Dilworth ◽  
Carolyn Von Allmen
Keyword(s):  
Culture Medium ◽  
Culture Fluid ◽  
Clonal Variation ◽  
Fresh Culture

ABSTRACT Clones of Paramecium of identical serotype when cultured in test tubes may differ in their ability to give rise to subclones of this serotype. Characteristically, stable clones yield progeny indistinguishable from their parents, while from unstable clones diverse subclones with new serotypes can be isolated repeatedly. Stable lines are resistant to changes in culture medium and also are unaffected by most sera. In contrast, the numbers and kinds of serotypes displayed among subclones derived from unstable lines are often affected by these same agents. Stable and unstable clones are interconvertible when the medium from individual cultures is repeatedly and frequently replaced by fresh culture fluid. This effect is very likely a result of the removal of the initial exhausted medium with any cell products rather than the addition of fresh nutrient.

Flanged Acrylic Plastic Hemispherical Shells for Undersea Application

1975 ◽  
Vol 97 (1) ◽  
pp. 1-9 ◽  
Author(s):  
J. D. Stachiw ◽  
J. R. Maison
Keyword(s):  
Finite Element ◽  
Hydrostatic Pressure ◽  
Stress Distribution ◽  
Boundary Conditions ◽  
Critical Pressure ◽  
Convex Surface ◽  
Elastic Analysis ◽  
Short Term ◽  
Acrylic Plastic ◽  
Hemispherical Shells

The effects of an equatorial flange and a nonuniform wall thickness upon the critical pressure and stress distribution in acrylic plastic hemispheres have been investigated by experimental and analytical methods. Forty acrylic hemispheres were fabricated and tested to destruction under short term hydrostatic pressure applied on the convex surface. Dome apex displacements were obtained from each specimen and strains were obtained from a selected few. A finite element elastic analysis was performed on one window configuration for two different boundary conditions and the experimentally derived stresses were used to determine which boundary conditions was the best for analytical analysis.

67 The growth and development of invivo-derived dromedary embryos during short-term incubation: Use of embryo holding medium and the effect of embryonic morphology

2021 ◽  
Vol 33 (2) ◽  
pp. 140
Author(s):  
B. Asadi ◽  
F. Seyedasgari
Keyword(s):  
Growth And Development ◽  
Culture Medium ◽  
Calf Serum ◽  
Daily Basis ◽  
Developmental Competence ◽  
Dromedary Camel ◽  
Short Term ◽  
Experimental Media ◽  
Further Development ◽  
Short Term Culture

Production of invivo embryos for transfer in dromedary camel is a well-established practice, whereas freezing of these embryos is still an ongoing challenge. A common approach in evaluation of freeze–thawing method is achieved by studying invitro development of frozen–thawed embryos. However, not much is known about the development pattern of fresh dromedary embryos during incubation. The objectives of this study were to evaluate the usefulness of commercial holding media for easy short-term culture of these embryos and to provide preliminary insights on the growth and development of hatched blastocysts with different shapes. Recovered hatched blastocysts from superovulated donors were graded as transferable and non-transferable. Embryos with significant folding or crinkliness were further categorized as collapsed, whereas those with a round or oval appearance were categorized as spherical. Culture was performed in 500-μL drops at 38.5°C, 5% O2, 0–6% CO2, and maximum humidity in groups of 2 to 4. The 4 experimental media included culture medium (CM; TCM-199, 10% fetal calf serum (FCS), 0.3mM sodium pyruvate, 2.2mg mL−1 sodium bicarbonate), serum-supplemented holding medium (SSH; Syngro+10% FCS), serum-free holding medium (Syngro) and V-Onestep (Vitromed). In experiment 1, a total of 36 embryos were assigned to 4 groups and further development of the embryos was monitored up to 96h by morphological evaluations, identifying static and degenerating embryos on daily basis. In experiment 2, a total of 16 spherical and 16 collapsed embryos were cultured in SSH and CM and two-thirds of the culture drop was replaced with fresh medium at 72h. The proportion of developing embryos and their size expansion was compared between treatments by Fisher’s test and Mann–Whitney U test, respectively. Statistically similar proportions of embryos continued to develop in all media within the first 48h despite a numeric advantage in CM group; at 72h, the proportion of growing embryos was significantly higher in CM (77.8%) and SSH (66.6%) compared with SFH (11.1%) and OneStep (22.2%) (P<0.05). None of the embryos in SFH and only 1 embryo in the V-Onestep group survived beyond 72h, whereas 3/9 embryos in SSH and 7/9 embryos in CM continued to expand. In experiment 2, the proportion of spherical embryos that developed was higher compared with their collapsed counterparts (8/8 in both groups vs. 5/8 and 4/8 in CM and SSH, respectively) at 24h. However, remaining collapsed embryos grew and expanded at similar rates to spherical ones in each group (P>0.05). Replacing the medium did not favour continuation of embryonic growth in SSH beyond 72 h; only 5/16 embryos survived to 96h compared with 12/16 in CM. In conclusion, serum-supplemented commercial holding preparations provide comparable results to culture medium for short-term incubation of invivo dromedary embryos. Natural collapsing of hatched blastocysts might be associated with lower developmental competence.

scholarly journals Short-term storage in vitro and large-scale propagation of grapevine genotypes

2012 ◽  
Vol 47 (3) ◽  
pp. 344-350 ◽  
Author(s):  
Rafael de Carvalho Silva ◽  
Zanderluce Gomes Luis ◽  
Jonny Everson Scherwinski-Pereira
Keyword(s):  
Survival Rate ◽  
Large Scale ◽  
Culture Medium ◽  
Short Term ◽  
Minimal Growth ◽  
Short Term Storage ◽  
Term Storage ◽  
Storage Temperatures ◽  
Number Of Shoots

The objective of this work was to evaluate the large-scale propagation of grapevine genotypes after short-term storage in vitro. Microshoots from ten grapevine genotypes were used. The following storage temperatures were evaluated: 10, 20, and 25°C. After short-term storage, the shoots were propagated in up to five successive subcultures, to assess the large-scale propagation of the germplasm maintained under conditions of minimal growth. The propagated shoots were rooted in different concentrations of indolbutiric acid (IBA) and acclimatized in greenhouse. The best temperature for short-term storage in vitro and survival of the genotypes was 20°C. In the propagation phase, the highest number of shoots per explant was found in the subcultures 4 and 5, with averages of 4.9 and 4.8 shoots per explant, respectively. In the rooting phase, the best results for number of roots were obtained using a culture medium supplemented with 0.4 µmol L-1 of IBA, with an average of three roots per shoot. During the acclimation phase, a survival rate higher than 95% was achieved after 30 days in the greenhouse. Grapevine genotypes maintained for six months in vitro, at 20ºC, can be micropropagated in large scale.

Failure Analysis of Glass-Reinforced Epoxy Pipes Under Internal Hydrostatic Pressure: A Comparison With the Split Disk Test Method

2017 ◽  
Vol 140 (1) ◽  
Author(s):  
H. R. Mahdavi ◽  
G. H. Rahimi ◽  
A. Farrokhabadi
Keyword(s):  
Hydrostatic Pressure ◽  
Failure Mechanisms ◽  
Failure Surface ◽  
Test Method ◽  
Short Term ◽  
Filament Wound ◽  
Short Term Test ◽  
Pressure Test ◽  
Type Of Failure ◽  
Disk Test

In this paper, the ultimate hoop strength of an industrial (±55 deg)9 filament-wound glass-reinforced epoxy (GRE) pipe as a short-term test is determined according to the ASTM D-1599 standard by performing the internal hydrostatic pressure test. After the test, the failure surface of the pipe is photographed by a high magnification camera, and in addition, the explanations are presented about the type of failure. The main purpose of this study is to compare the results obtained for the ultimate hoop strength and failure mechanisms of the pipe by using the internal hydrostatic pressure test with that by the split disk test method according to the ASTM D-2290 standard in the previous work.

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