GROWTH FACTOR RELATIONSHIPS OF SOIL MICROORGANISMS AS AFFECTED BY PROXIMITY TO THE PLANT ROOT

1959 ◽  
Vol 5 (4) ◽  
pp. 323-334 ◽  
Author(s):  
F. D. Cook ◽  
A. G. Lochhead
Keyword(s):  
Growth Factors ◽  
Growth Factor ◽  
Root Zone ◽  
Plant Root ◽  
Vitamin B ◽  
Control Soil ◽  
Direct Stimulation ◽  
Soil Rhizosphere ◽  
Growth Promoting ◽  
Stimulation Of

A comparison was made of the growth factor requirements and growth factor synthesizing capacity of bacteria from control soil, rhizosphere, and rhizoplane of wheat. Organisms for which growth factors were essential were proportionately much less abundant at or near the root than in more distant soil; this is ascribed chiefly to lower percentages of forms requiring thiamine, biotin, and vitamin B12. At the rhizoplane proportions of bacteria requiring growth factors were as low as, or lower than, in the rhizosphere. Bacteria capable of synthesizing growth-promoting substances were proportionately much more numerous in the root zone than in control soil. Somewhat greater capacity was shown by rhizoplane than by rhizosphere isolates. Fungi characteristic of the rhizoplane showed the highest capacity for vitamin production.The occurrence of growth-promoting substances at or near the root is attributable chiefly to microbial synthesis rather than to root excretion. This is the reverse of the situation believed to exist respecting amino acids. The preferential stimulation of growth factor synthesizing organisms is regarded as an indirect effect of plant growth—a reflection of the direct stimulation of amino acid requiring forms, a group with pronounced capacity for vitamin synthesis.

Evidence that thyroid growth promoting activity of immunoglobulin preparations is due to contamination with EGF

1987 ◽  
Vol 116 (1_Suppl) ◽  
pp. S256-S259 ◽  
Author(s):  
R. Gärtner ◽  
C. Tsavella ◽  
G. Bechtner ◽  
W. Greil
Keyword(s):  
Growth Factors ◽  
Growth Factor ◽  
Egf Receptor ◽  
Protein A ◽  
Graves Disease ◽  
Thyroid Cell ◽  
Immunoglobulin Preparations ◽  
Receptor Assay ◽  
Epidermal Growth ◽  
Growth Promoting

Abstract. Immunoglobulin (IG) preparations may be contaminated with growth factors. Therefore, we investigated whether the growth promoting activity in IG preparations (thyroid growth stimulating immunoglobulins = TGI) from patients with sporadic goitre may be caused by contaminating EGF (epidermal growth factor). EGF in sera as well as in indifferently prepared IG of patients with recurrent goitre (n = 23), Graves' disease (n = 19) and normals (n = 17) was determined by EGF receptor assay. Comparatively, the ability for stimulating thyroid cell growth was determined in these IG preparations (2 mg/ml). EGF in ammoniumsulphate (AS) precipitates was about 2-fold higher than serum EGF. The growth promoting activity of indifferent IG preparations correlated with the EGF content. After additional purification on protein A-sepharose, neither EGF, nor a growth promoting activity was found in these IG preparations. We therefore conclude, that the growth promoting activity of crude IG preparations may be due to a contamination with EGF.

scholarly journals Growth factors are released by mechanically wounded endothelial cells.

1989 ◽  
Vol 109 (2) ◽  
pp. 811-822 ◽  
Author(s):  
P L McNeil ◽  
L Muthukrishnan ◽  
E Warder ◽  
P A D'Amore
Keyword(s):  
Endothelial Cells ◽  
Plasma Membrane ◽  
Growth Factors ◽  
Growth Factor ◽  
Mechanical Forces ◽  
Fibroblast Growth ◽  
Growth Promoting ◽  
Transient Plasma

Growth factors may be required at sites of mechanical injury and normal wear and tear in vivo, suggesting that the direct action of mechanical forces on cells could lead to growth factor release. Scraping of cells from the tissue culture substratum at 37 degrees C was used to test this possibility. We show that scraping closely mimics in vitro both the transient plasma membrane wounds observed in cells subject to mechanical forces in vivo (McNeil, P. L., and S. Ito. 1989. Gastroenterology. 96:1238-1248) and the transient plasma membrane wounds shown here to occur in endothelial cells under normal culturing conditions. Scraping of endothelial cells from the culturing substratum released into the culture medium a potent growth-promoting activity for Swiss 3T3 fibroblasts. Growth-promoting activity was released rapidly (within 5 min) after scraping but was not subsequently degraded by the endothelial cells for at least 24 h thereafter. A greater quantity of growth-promoting activity was released by cells scraped 4 h after plating than by those scraped 4 or 7 d afterwards. Thus release is not due to scraping-induced disruption of extracellular matrix. Release was only partially cold inhibitable, was poorly correlated with the level of cell death induced by scraping, and did not occur when cells were killed with metabolic poisons. These results suggest that mechanical disruption of plasma membrane, either transient or permanent, is the essential event leading to release. A basic fibroblast growth factor-like molecule and not platelet-derived growth factor appears to be partially responsible for the growth-promoting activity. We conclude that one biologically relevant route of release of basic fibroblast growth factor, a molecule which lacks the signal peptide sequence for transport into the endoplasmic reticulum, could be directly through mechanically induced membrane disruptions of endothelial cells growing in vivo and in vitro.

Late signals are required for the stimulation of DNA synthesis in rat mammary fibroblasts by growth factors

1996 ◽  
Vol 16 (3) ◽  
pp. 249-263 ◽  
Author(s):  
Hai-Lan Chen ◽  
Philip S. Rudland ◽  
John A. Smith ◽  
David G. Fernig
Keyword(s):  
Growth Factors ◽  
Growth Factor ◽  
Dna Synthesis ◽  
Maximal Response ◽  
High Concentration ◽  
Initial Concentration ◽  
Maximal Stimulation ◽  
Epidermal Growth ◽  
Lag Period ◽  
Stimulation Of

Maximal stimulation of DNA synthesis in quiescent rat mammary (Rama) 27 fibroblasts is elicited by epidermal growth factor (EGF) or basic fibroblast growth factor (bFGF) 18 h after the initial addition of the growth factors-the ‘lag’ period. At maximally-stimulating concentrations, EGF and bFGF are interchangeable 9 h after their initial addition. When the initial concentration of growth factor is below that required to elicit a maximal response, it is possible to increase the level of DNA synthesis by increasing the concentration of growth factor 9 h after its initial addition. When the initial concentration of growth factor is high, substitution by a lower concentration of growth factor after 9 h allows a greater proportion of cells to synthesize DNA than would be expected from a continuous low dose of growth factor. Similar results are obtained when both the growth factor and its concentration are changed 9 h after the initial addition of growth factor. However, when EGF at a low concentration is substituted for a high concentration of EGF or bFGF the resulting increase in the levels of DNA synthesis is greater when EGF rather than bFGF is added for a second time. The half-life of the growth-stimulatory signals delivered by EGF and by bFGF 9 h after their initial addition is 1–2 h. These results suggest that to stimulate DNA synthesis: (i) EGF or bFGF must deliver a signal(s) continuously; (ii) the initial signals produced by EGF and bFGF are equivalent; (iii) the signals produced between 9–18 h by EGF may be different to those produced by bFGF.

Effect of water-soluble extract from antler of wapiti (Cervus elaphus) on the growth of fibroblasts

1997 ◽  
Vol 77 (2) ◽  
pp. 343-345 ◽  
Author(s):  
H. H. Sunwoo ◽  
T. Nakano ◽  
J. S. Sim
Keyword(s):  
Growth Factor ◽  
Cell Growth ◽  
Cervus Elaphus ◽  
Water Soluble ◽  
Soluble Extract ◽  
Key Words Growth ◽  
Growth Promoting ◽  
Water Soluble Extract ◽  
Dose Dependent ◽  
Stimulation Of

The water-soluble extracts were prepared from the tip sections of antlers of 4-yr-old wapiti stags, and the effect of extract on the growth of bovine skin fibroblasts in culture was examined. The results showed the presence of growth promoting factor(s) in the antler extract. The stimulation of cell growth was found to be dose dependent (P < 0.05). Key words: Growth factor, antler, wapiti, fibroblast

scholarly journals Direct Stimulation of Adult Neural Stem Cells In Vitro and Neurogenesis In Vivo by Vascular Endothelial Growth Factor

2006 ◽  
Vol 14 (3) ◽  
pp. 237-248 ◽  
Author(s):  
Anne Schänzer ◽  
Frank-Peter Wachs ◽  
Daniel Wilhelm ◽  
Till Acker ◽  
Christiana Cooper-Kuhn ◽  
...  
Keyword(s):  
Stem Cells ◽  
Vascular Endothelial Growth Factor ◽  
Growth Factor ◽  
Neural Stem Cells ◽  
Vascular Endothelial ◽  
Direct Stimulation ◽  
Endothelial Growth Factor ◽  
Stimulation Of

Regeneration neurohormones and growth factors in echinoderms

2001 ◽  
Vol 79 (7) ◽  
pp. 1171-1208 ◽  
Author(s):  
M C Thorndyke ◽  
MD Candia Carnevali
Keyword(s):  
Growth Factors ◽  
Growth Factor ◽  
Transforming Growth Factor ◽  
Molecular Level ◽  
Distribution Patterns ◽  
Transforming Growth Factor Β ◽  
Regenerative Processes ◽  
Blastema Formation ◽  
Undifferentiated Cells ◽  
Growth Promoting

There has been much recent interest in the presence and biological functions of growth regulators in invertebrates. In spite of the different distribution patterns of these molecules in different phyla (from molluscs, insects, and annelids to echinoderms and tunicates), they seem always to be extensively involved in developmental processes, both embryonic and regenerative. Echinoderms are well known for their striking regenerative potential and many can completely regenerate arms that, for example, are lost following self-induced or traumatic amputation. Thus, they provide a valuable experimental model for the study of regenerative processes from the macroscopic to the molecular level. In crinoids as well as probably all ophiuroids, regeneration is rapid and occurs by means of a mechanism that involves blastema formation, known as epimorphosis, where the new tissues arise from undifferentiated cells. In asteroids, morphallaxis is the mechanism employed, replacement cells being derived from existing tissues following differentiation and (or) transdifferentiation. This paper focuses on the possible contribution of neurohormones and growth factors during both repair and regenerative processes. Three different classes of regulatory molecules are proposed as plausible candidates for growth-promoting factors in regeneration: neurotransmitters (monoamines), neuropeptides (substance P, SALMFamides 1 and 2), and growth-factor-like molecules (TGF-β (transforming growth factor β), NGF (nerve growth factor), RGF-2 (basic fibroblast growth factor)).

scholarly journals Serum factors, growth factors and UDP-sugar metabolism in bovine articular cartilage chondrocytes

1994 ◽  
Vol 303 (3) ◽  
pp. 713-721 ◽  
Author(s):  
G E Ysart ◽  
R M Mason
Keyword(s):  
Growth Factors ◽  
Articular Cartilage ◽  
Growth Factor ◽  
Transforming Growth Factor Beta ◽  
Transforming Growth Factor ◽  
Sugar Metabolism ◽  
Tgf Beta ◽  
Serum Factors ◽  
Bovine Articular Cartilage ◽  
Stimulation Of

1. The effect of different batches of fetal bovine serum and of growth factors on [35S]sulphate incorporation into glycosaminoglycans and on UDP-sugar pools in explant cultures of bovine articular cartilage was investigated. 2. [35S]Sulphate incorporation was variably stimulated between 1.2- and 3.5-fold by four different batches of serum. The UDP-glucuronate pool size expanded 4.3-6.5-fold in the presence of serum, even in those cultures in which little stimulation of [35S]sulphate incorporation occurred. The UDP-N-acetylhexosamine and UDP-hexose pools expanded by about 1.5- and 2.0-fold respectively in the presence of serum. UDP-xylose was not detected. 3. Equilibrium-labelling and pulse-chase experiments with D-[1-3H]glucose indicated that the rate of flux through the UDP-sugar pools was unaffected by serum. UDP-hexose, UDP-N-acetylhexosamine and UDP-glucuronate have approximate half-lives (t1/2) of 7, 12 and 3-4 min respectively. At equilibrium, the 3H specific activities of UDP-hexose and UDP-N-acetylhexosamine were very similar but that for the UDP-glucuronate pool was much higher, especially in serum-supplemented cultures. The results suggest that UDP-glucuronate synthesis occurs via a pathway which is independent of the main UDP-hexose pathway. 4. Supplementing cultures with heat-treated serum had no effect on the serum-induced expansion of UDP-sugar pools but stimulation of [35S]sulphate incorporation into glycosaminoglycans was 50% lower than for native serum. Acid-treated serum promoted a 2-fold expansion of the UDP-glucuronate and UDP-N-acetylhexosamine pool over that obtained with native serum but was 20% less effective in stimulating [35S]sulphate incorporation than the latter. Prior dialysis of serum had no effect on its modulatory action on either [35S]sulphate incorporation or on the size of UDP-sugar pools. 5. Insulin-like growth factor 1 (IGF-1), transforming growth factor beta-1 (TGF beta-1), platelet-derived growth factor (PDGF) (BB homodimer) and epidermal growth factor (EGF) all stimulated [35S]sulphate incorporation into glycosaminoglycans as expected. The UDP-glucuronate pool expanded by 1.5- and 2.0-fold in the presence of IGF-1 and TGF beta-1 respectively, and by about 1.8-fold in the presence of PDGF or EGF. None of the factors investigated, or combinations of IGF-1 and TGF beta-1 or IGF-1 and EGF, stimulated expansion of the UDP-glucuronate pool to the same extent as native serum.(ABSTRACT TRUNCATED AT 400 WORDS)

Stimulation of intestinal epithelial cell proliferation in culture by growth factors in human and ruminant mammary secretions

1987 ◽  
Vol 113 (2) ◽  
pp. 285-290 ◽  
Author(s):  
A. N. Corps ◽  
K. D. Brown
Keyword(s):  
Growth Factors ◽  
Growth Factor ◽  
Intestinal Epithelial ◽  
Epithelial Cell Proliferation ◽  
Factor I ◽  
Maximal Stimulation ◽  
Igf I ◽  
Epidermal Growth ◽  
Dose Dependent ◽  
Stimulation Of

ABSTRACT Samples of human and ruminant mammary secretions stimulated the proliferation of rat intestinal epithelial (RIE-1) cells in culture. The stimulation was dose-dependent, and samples taken prepartum had greater potency than those taken after parturition. When various hormones and growth factors known to be present in milk were tested, only epidermal growth factor (EGF), insulin and insulin-like growth factor I (IGF-I) stimulated the proliferation of RIE-1 cells. IGF-I was effective at lower concentrations than insulin, and the maximal stimulation induced by each of these two polypeptides was greater than that induced by EGF. The maximal stimulation induced by samples of mammary secretions was similar to that induced by insulin or IGF-I. J. Endocr. (1987) 113, 285–290

scholarly journals Comparative analysis of local stimulation methods of reparative osteogenesis

2021 ◽  
pp. 41-49
Author(s):  
M. L. Mukhanov ◽  
A. N. Blazhenko ◽  
S. B. Bogdanov ◽  
A. S. Sotnichenko ◽  
T. V. Rusinova ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Growth Factors ◽  
Comparative Analysis ◽  
Growth Factor ◽  
Transforming Growth Factor ◽  
Original Method ◽  
Osteogenic Potential ◽  
Reparative Osteogenesis ◽  
Local Stimulation ◽  
Stimulation Of

Objective To determine the ratio of the main growth factors when using various methods of local stimulation of reparative osteogenesis.Material and methods The study consisted of two parts: in the first part a comparative analysis of the content of growth factors by ELISA was carried out (PDGF – platelet derived growth factor, TGF – transforming growth factor, VEGF – vascular endothelial growth factor, IGF – insulin-like growth factor, BMP6 and BMP7 – morphogenetic proteins 6 and 7), capable of stimulating reparative osteogenesis in blood plasma, plateletrich plasma, red bone marrow and bone autoregenerate. The second part presented the results of approbation of the autoregenerate obtained according to the original method in the framework of an acute experiment on animals.Results The most important cytokines affecting the process of reparative osteogenesis are fibroblast growth factor – FGF1 and bone morphogenetic protein 7 – BMP7. Based on the results of a comparative enzymelinked immunosorbent assay, it has been established that the autoregenerate, obtained by the original method, and a bone marrow aspirate concentrate have the highest osteogenic potential.Conclusion Autoregenerate is an effective and promising means of local stimulation of reparative osteogenesis, and its transplantation is a simple and highly effective procedure.

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