The Influence of Physical Factors on Xylem Differentiation In Vitro

1983 ◽  
pp. 88-102 ◽  
Author(s):  
Lorin W. Roberts
Keyword(s):  
Physical Factors ◽  
Xylem Differentiation

scholarly journals Ovaries of Chrysanthemum Irradiated with High-Energy Photons and High-Energy Electrons Can Regenerate Plants with Novel Traits

Agronomy ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1111
Author(s):  
Natalia Miler ◽  
Iwona Jedrzejczyk ◽  
Seweryn Jakubowski ◽  
Janusz Winiecki
Keyword(s):  
Total Dose ◽  
In Vitro Regeneration ◽  
High Energy ◽  
Mutation Breeding ◽  
Chrysanthemum Morifolium ◽  
Physical Factors ◽  
Strong Impact ◽  
Breeding Method ◽  
High Energy Electrons

Classical mutation breeding using physical factors is a common breeding method for ornamental crops. The aim of our study was to examine the utility of ovaries excised from irradiated inflorescences of Chrysanthemum × morifolium (Ramat.) as explants for breeding purposes. We studied the in vitro regeneration capacity of the ovaries of two chrysanthemum cultivars: ‘Profesor Jerzy’ and ‘Karolina’ preceded by irradiation with high-energy photons (total dose 5, 10 and 15 Gy) and high-energy electrons (total dose 10 Gy). Growth and inflorescence parameters of greenhouse acclimatized regenerants were recorded, and ploidy level was estimated with flow cytometry. The strong impact of genotype on regeneration efficiency was recorded—cultivar ‘Karolina’ produced only 7 viable shoots, while ‘Profesor Jerzy’ produced totally 428 shoots. With an increase of irradiation dose, the regeneration decreased, the least responsive were explants irradiated with 15 Gy high-energy photons and 10 Gy high-energy electrons. Regenerants of ‘Profesor Jerzy’ obtained from these explants possessed shorter stem and flowered later. The highest number of stable, color and shape inflorescence variations were obtained from explants treated with 10 Gy high-energy photons. Variations of inflorescences were predominantly changes of shape—from full to semi-full. New color phenotypes were dark yellow, light yellow and pinkish, among them only the dark yellow phenotype remained stable during second year cultivation. None of the regenerants were haploid. The application of ovaries irradiated within the whole inflorescence of chrysanthemum can be successfully applied in the breeding programs, provided the mother cultivar regenerate in vitro efficiently.

Effect of chemical and physical factors in in vitro propagation and volatile fraction analysis ofAloysia triphylla(L’Herit) Britton

2017 ◽  
pp. 309-316
Author(s):  
G.M. Silva ◽  
J.P. Alvarenga ◽  
S.K.V. Bertolucci ◽  
M.C. Tavares ◽  
M.A. Rodrigues ◽  
...  
Keyword(s):  
In Vitro Propagation ◽  
Volatile Fraction ◽  
Physical Factors

scholarly journals Role of mechanical cues and hypoxia on the growth of tumor cells in strong and weak confinement: A dual in vitro–in silico approach

2020 ◽  
Vol 6 (13) ◽  
pp. eaaz7130 ◽  
Author(s):  
V. Le Maout ◽  
K. Alessandri ◽  
B. Gurchenkov ◽  
H. Bertin ◽  
P. Nassoy ◽  
...  
Keyword(s):  
In Silico ◽  
Time Course ◽  
Growth Dynamics ◽  
Tumor Model ◽  
Mechanistic Modeling ◽  
Physical Factors ◽  
Factors Affecting ◽  
Numerical Studies

Characterization of tumor growth dynamics is of major importance for cancer understanding. By contrast with phenomenological approaches, mechanistic modeling can facilitate disclosing underlying tumor mechanisms and lead to identification of physical factors affecting proliferation and invasive behavior. Current mathematical models are often formulated at the tissue or organ scale with the scope of a direct clinical usefulness. Consequently, these approaches remain empirical and do not allow gaining insight into the tumor properties at the scale of small cell aggregates. Here, experimental and numerical studies of the dynamics of tumor aggregates are performed to propose a physics-based mathematical model as a general framework to investigate tumor microenvironment. The quantitative data extracted from the cellular capsule technology microfluidic experiments allow a thorough quantitative comparison with in silico experiments. This dual approach demonstrates the relative impact of oxygen and external mechanical forces during the time course of tumor model progression.

scholarly journals Regulation and Directing Stem Cell Fate by Tissue Engineering Functional Microenvironments: Scaffold Physical and Chemical Cues

2019 ◽  
Vol 2019 ◽  
pp. 1-16 ◽  
Author(s):  
Fei Xing ◽  
Lang Li ◽  
Changchun Zhou ◽  
Cheng Long ◽  
Lina Wu ◽  
...  
Keyword(s):  
Tissue Engineering ◽  
Stem Cells ◽  
Stem Cell ◽  
Growth Factors ◽  
Cell Fate ◽  
Chemical Cues ◽  
Physical Factors ◽  
Stem Cell Fate ◽  
Physical And Chemical

It is well known that stem cells reside within tissue engineering functional microenvironments that physically localize them and direct their stem cell fate. Recent efforts in the development of more complex and engineered scaffold technologies, together with new understanding of stem cell behavior in vitro, have provided a new impetus to study regulation and directing stem cell fate. A variety of tissue engineering technologies have been developed to regulate the fate of stem cells. Traditional methods to change the fate of stem cells are adding growth factors or some signaling pathways. In recent years, many studies have revealed that the geometrical microenvironment played an essential role in regulating the fate of stem cells, and the physical factors of scaffolds including mechanical properties, pore sizes, porosity, surface stiffness, three-dimensional structures, and mechanical stimulation may affect the fate of stem cells. Chemical factors such as cell-adhesive ligands and exogenous growth factors would also regulate the fate of stem cells. Understanding how these physical and chemical cues affect the fate of stem cells is essential for building more complex and controlled scaffolds for directing stem cell fate.

Invited Review: Mechanochemical signal transduction in the fetal lung

2000 ◽  
Vol 89 (5) ◽  
pp. 2078-2084 ◽  
Author(s):  
Mingyao Liu ◽  
Martin Post
Keyword(s):  
Signal Transduction ◽  
Cell Proliferation ◽  
Fetal Lung ◽  
Mechanical Stretch ◽  
Model Systems ◽  
Lung Cells ◽  
Physical Factors ◽  
Lung Maturation

Growth and maturation of fetal lungs are regulated by both humoral and physical factors. Mechanical stretch stimulates fetal lung cell proliferation and affects fetal lung maturation by influencing the production of extracellular matrix molecules and the expression of specific genes of fetal lung cells. These effects are mediated through special signal transduction pathways in fetal lung cells. Various in vivo and in vitro model systems have been developed to investigate the mechanotransduction process. The diversity and discrepancy of these studies have raised many questions. We will briefly summarize mechanical force-induced signals in fetal lung cell proliferation and differentiation and then discuss several important issues related to these studies.

Functional Tissue Engineering: The Role of Biomechanics

2000 ◽  
Vol 122 (6) ◽  
pp. 570-575 ◽  
Author(s):  
David L. Butler ◽  
Steven A. Goldstein ◽  
Farshid Guilak
Keyword(s):  
Mechanical Properties ◽  
Tissue Engineering ◽  
Physical Factors ◽  
Cellular Activity ◽  
Biosynthetic Activity ◽  
Functional Tissue Engineering ◽  
Functional Tissue ◽  
Engineered Tissues

“Tissue engineering” uses implanted cells, scaffolds, DNA, protein, and/or protein fragments to replace or repair injured or diseased tissues and organs. Despite its early success, tissue engineers have faced challenges in repairing or replacing tissues that serve a predominantly biomechanical function. An evolving discipline called “functional tissue engineering” (FTE) seeks to address these challenges. In this paper, the authors present principles of functional tissue engineering that should be addressed when engineering repairs and replacements for load-bearing structures. First, in vivo stress/strain histories need to be measured for a variety of activities. These in vivo data provide mechanical thresholds that tissue repairs/replacements will likely encounter after surgery. Second, the mechanical properties of the native tissues must be established for subfailure and failure conditions. These “baseline data” provide parameters within the expected thresholds for different in vivo activities and beyond these levels if safety factors are to be incorporated. Third, a subset of these mechanical properties must be selected and prioritized. This subset is important, given that the mechanical properties of the designs are not expected to completely duplicate the properties of the native tissues. Fourth, standards must be set when evaluating the repairs/replacements after surgery so as to determine, “how good is good enough?” Some aspects of the repair outcome may be inferior, but other mechanical characteristics of the repairs and replacements might be suitable. New and improved methods must also be developed for assessing the function of engineered tissues. Fifth, the effects of physical factors on cellular activity must be determined in engineered tissues. Knowing these signals may shorten the iterations required to replace a tissue successfully and direct cellular activity and phenotype toward a desired end goal. Finally, to effect a better repair outcome, cell-matrix implants may benefit from being mechanically stimulated using in vitro “bioreactors” prior to implantation. Increasing evidence suggests that mechanical stress, as well as other physical factors, may significantly increase the biosynthetic activity of cells in bioartificial matrices. Incorporating each of these principles of functional tissue engineering should result in safer and more efficacious repairs and replacements for the surgeon and patient. [S0148-0731(00)00206-5]

scholarly journals A METHOD FOR THE PHYSIOLOGICAL STUDY OF TISSUES IN VITRO

1923 ◽  
Vol 38 (4) ◽  
pp. 407-418 ◽  
Author(s):  
Alexis Carrel
Keyword(s):  
Nutrient Medium ◽  
Bacterial Contamination ◽  
Culture Medium ◽  
Residual Activity ◽  
Physical Factors ◽  
Dynamic Changes ◽  
Fluid Medium ◽  
Continuous Growth ◽  
Pure Cultures

1. A method has been developed which allows the continuous growth of pure strains of fibroblasts, epithelium, and leucocytes in a medium which undergoes but slight spontaneous deterioration. 2. The principle of the method is to leave the tissues undisturbed while the medium is changed. This was realized by special containers allowing the change of the medium without bacterial contamination and by the simultaneous use of a solid and a fluid medium. 3. The curve of growth of pure cultures of fibroblasts and epithelial cells in a nutrient medium is a parabola; in a non-nutrient medium, it is S-shaped and expresses the residual activity of the tissues. Leucocytes invade the culture medium progressively, as do bacteria, but never aggregate in a tissue. 4. The method is used for the study of the morphological and dynamic changes occurring in tissues under the influence of chemical and physical factors.

Influence of physical factors on the growth of insect cells in vitro

In Vitro ◽  
1974 ◽  
Vol 10 (3-4) ◽  
pp. 149-156 ◽  
Author(s):  
T. J. Kurtti ◽  
Surendra P. S. Chaudhary ◽  
Marion A. Brooks
Keyword(s):  
Insect Cells ◽  
Physical Factors

scholarly journals Physical Factors That Affect In Vitro Autographa californica Nuclear Polyhedrosis Virus Infection

1981 ◽  
Vol 41 (5) ◽  
pp. 1166-1172 ◽  
Author(s):  
Edward M. Dougherty ◽  
Ronald M. Weiner ◽  
James L. Vaughn ◽  
Charles F. Reichelderfer
Keyword(s):  
Virus Infection ◽  
Nuclear Polyhedrosis Virus ◽  
Autographa Californica ◽  
Physical Factors ◽  
Polyhedrosis Virus ◽  
Nuclear Polyhedrosis

In vitro rumen degradation of legumes in south Sumatra, Indonesia

1998 ◽  
Vol 22 ◽  
pp. 241-243
Author(s):  
A. Fariani ◽  
L. Warly ◽  
T. Ichinohe ◽  
T. Fujihara
Keyword(s):  
Cell Wall ◽  
Nutritive Value ◽  
Rumen Fluid ◽  
Farming Systems ◽  
Gas Production ◽  
Physical Factors ◽  
Rumen Degradation ◽  
Tropical Legumes ◽  
Major Factors

Legumes have a significant role in many farming systems of the tropics and subtropics through their contribution to enhanced nutritive value of the animal diet, biological nitrogen fixation and landscape stability (Humphreys, 1995). The great potential of legumes to increase productivity of livestock is being related with their high content of nutrients, especially protein and other nutrients often deficient in grass or low quality hay diets for ruminants. In Indonesia, legumes are often used for replacement of costly concentrate in ruminants diets. Norton and Poppi (1995) reported that quality of tropical legumes varies between and within species but is generally higher than that of tropical grasses. It is well known that the major factors limiting intake and digestibility are those associated with rate and extent of forage degradation by microbial and physical factors in the rumen, primarily the amount of cell wall constituents and the extent of lignification. Association of polysaccharides of cell wall with lignin hinders attack by microbial enzymes and prevents the physical attachment of bacteria to the cell wall. Menke et al. (1979) reported that the amount of gas released when a food is incubated in vitro in the rumen fluid, is also closely related to digestibility of the food and could be used to predict food intake. There is very little information available on the rumen degradation characteristics and in vitro gas production of the tropical legumes. Objectives of the present study were to assess differences in in vitro degradation and gas production between five commonly used legumes in south Sumatra, Indonesia.

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