The Differential Growth-Response of Embryonic Chick Limb-Bone Rudiments to Triiodothyronine in vitro. III. Hormone Concentration.

Development ◽  
1963 ◽  
Vol 11 (2) ◽  
pp. 383-398
Author(s):  
Kirstie Lawson
Keyword(s):  
Growth Rate ◽  
Growth Response ◽  
Specific Growth ◽  
Differential Growth ◽  
Limb Bone ◽  
Limb Bones ◽  
High Specific Growth Rate ◽  
Specific Growth Rates

Rudiments of each of the limb bones from the same chick embryo differ in their growth response to thyroid hormones in vitro (Fell & Mellanby, 1955, 1956). These variations in response to triiodothyronine (T3) are not determined by differences in maturity or size of the rudiments (Lawson, 1961a), but are associated with differences in their normal specific growth rates in vivo; T3 retards the growth of rudiments which normally have a high specific growth rate and stimulates the growth of those which grow slowly in vivo. However, when the growth rate of the limb-bone rudiments is altered in vitro by varying the composition of the medium or the temperature, the characteristic responses of different rudiments to T3 are not greatly altered (Lawson, 1961b). For example, the effect of T3 on the radius, a slowly growing rudiment, is to stimulate growth, whereas the same amount of T3 retards the growth rate of the third metatarsus which is normally a fast growing bone.

The Differential Growth Response of Embryonic Chick Limb-bone Rudiments to Triiodothyronine in vitro

Development ◽  
1961 ◽  
Vol 9 (1) ◽  
pp. 42-51
Author(s):  
Kirstie Lawson
Keyword(s):  
Vitamin A ◽  
Thyroid Hormones ◽  
Growth Response ◽  
Nutritional Deficiencies ◽  
Embryonic Chick ◽  
Differential Growth ◽  
Relative Growth ◽  
Limb Bone ◽  
Leg Bones

The proportionate development of the embryonic chick skeleton can be influenced experimentally by a variety of factors such as nutritional deficiencies (Byerly, Titus, Ellis, & Landauer, 1935; Landauer, 1936; Romanoff & Bauernfeind, 1942; Couch, Cravens, Elvehjem, & Halpin, 1948), teratogens (Ancel & Lallemand, 1942; Zwilling & de Bell, 1950; Landauer, 1952, 1953a, 1954) and excess hormones (Willier, 1924; Landauer & Bliss, 1946; Duraiswami, 1950). The leg bones are generally more severely affected than the wing bones, but a comparison of the action of several teratogens on the character of the malformations and on the relative growth of the leg bones indicated that the response of individual bones varies with the different agents (Landauer & Rhodes, 1952; Landauer, 1953 a, b, 1954). Cartilaginous limb-bone rudiments also respond differentially when they are isolated from the embryo and exposed in culture to various compounds, such as insulin (Chen, 1954), vitamin A, and the thyroid hormones (Fell & Mellanby, 1955, 1956).

Fate of photosynthetic fixed carbon in light- and shade-adapted colonies of the symbiotic coral Stylophora pistillata

1984 ◽  
Vol 222 (1227) ◽  
pp. 181-202 ◽  
Keyword(s):  
Growth Rates ◽  
Specific Growth ◽  
Reductase Activity ◽  
Ammonium Uptake ◽  
Fixed Carbon ◽  
Stylophora Pistillata ◽  
Uptake Rates ◽  
Specific Growth Rates

The total daily flux of photosynthetically fixed carbon in light- and shade-adapted phenotypes of the symbiotic coral, Stylophora pistillata , was quantified. Light adapted corals fixed four times as much carbon and respired twice as much as shade corals. Specific growth rates of zooxanthellae in situ were estimated from average daily mitotic indices and from ammonium uptake rates (nitrate uptake or nitrate reductase activity could not be demonstrated). Specific growth rates were very low, demonstrating that of the total net carbon fixed daily, only a small fraction (less than 5 %) goes into zooxanthellae cell growth. The balance of the net fixed carbon (more than 95 %) is translocated to the host. New and conventional methods of measuring total daily translocation were compared. The ‘growth rate’ method, which does not employ 14 C, emerged as superior to the conventional in vitro and in vivo methods. The contribution of translocated carbon to animal maintenance res­piration (czar) was 143 % in light corals and 58 % in shade corals. Thus, translocation in the former could supply not only the total daily carbon needed for respiration but also a fraction of the carbon needed for growth. Whereas light-adapted corals released only 6%, shade-adapted corals released almost half of their total fixed carbon as dissolved or particulate organic material. This much higher throughput of organic carbon may possibly benefit the heterotrophic microbial community in shade environments.

The Differential Growth-response of Embryonic Chick Limb-bone Rudiments to Triiodothyronine in vitro

Development ◽  
1961 ◽  
Vol 9 (3) ◽  
pp. 534-555
Author(s):  
Kirstie Lawson
Keyword(s):  
Tissue Culture ◽  
Growth Response ◽  
Differential Response ◽  
Long Bone ◽  
Long Bones ◽  
Embryonic Chick ◽  
Differential Growth ◽  
Limb Bone ◽  
Stage Of Development

The maturation of the cartilage of embryonic chick long-bone rudiments growing in tissue culture is accelerated by addition of the thyroid hormones, thyroxine and triiodothyronine, but the growth in length of different long bones is not uniformly affected (Fell & Mellanby, 1955, 1956). Thus the growth of the hormone-treated tibia is less than that of a normal tibia, while the effect of thyroid hormone on the radius is to increase its growth. This differential response is not determined either by the stage of development at which the limb-bone rudiments are exposed to hormone, or by the size of the explant (Lawson, 1961). Investigations to determine whether the differential response of limb-bone rudiments to triiodothyronine (T3) is due to differences in the growth rates of different bones are described in this paper. The work was divided into three parts.

Oscillating conditions for influencing the composition of mixed biological cultures

1998 ◽  
Vol 37 (4-5) ◽  
pp. 259-262 ◽  
Author(s):  
Bjarne R. Horntvedt ◽  
Morten Rambekk ◽  
Rune Bakke
Keyword(s):  
Growth Rate ◽  
Specific Growth ◽  
Heterotrophic Bacteria ◽  
Bacterial Species ◽  
Rate Reduction ◽  
Similar Strategy ◽  
Sinusoidal Oscillations ◽  
Specific Growth Rates ◽  
Rate Limiting ◽  
Concentration Levels

This paper presents a strategy in which mixed biological cultures are exposed to oscillating concentration levels, to improve the potential for coexistence of desired bacterial species. A mechanistic mathematical model is constructed to investigate and illustrate this strategy. This paper is focused on competition between nitrifying, denitrifying and aerobic heterotrophic bacteria in a CSTR with sludge recycle. For nitrifying and aerobic heterotrophic cultures, the effect of sinusoidal oscillations in DO levels with an amplitude of 1.0 mg/l is a 16% specific growth rate reduction compared to that at a constant DO level. The denitrifiers growth rate is increased by an average of 59%, compared to the constant DO level situation. A similar strategy has been tested in a pilot plant. It is concluded that the influence on specific growth rates is a function of the amplitude of the oscillations. The effects are greatest when concentrations fluctuate around the half saturation concentration of the rate limiting component(s).

scholarly journals In Vivo Radioprotective Activity of Cell-Permeable Bifunctional Antioxidant Enzyme GST-TAT-SOD against Whole-Body Ionizing Irradiation in Mice

2017 ◽  
Vol 2017 ◽  
pp. 1-9 ◽  
Author(s):  
Jianru Pan ◽  
Huocong He ◽  
Ying Su ◽  
Guangjin Zheng ◽  
Junxin Wu ◽  
...  
Keyword(s):  
Growth Rate ◽  
Antioxidant Activity ◽  
Body Weight ◽  
Whole Body ◽  
White Pulp ◽  
Radioprotective Activity ◽  
Significant Difference ◽  
Wbc Count

GST-TAT-SOD was the fusion of superoxide dismutase (SOD), cell-permeable peptide TAT, and glutathione-S-transferase (GST). It was proved to be a potential selective radioprotector in vitro in our previous work. This study evaluated the in vivo radioprotective activity of GST-TAT-SOD against whole-body irradiation. We demonstrated that intraperitoneal injection of 0.5 ml GST-TAT-SOD (2 kU/ml) 2 h before the 6 Gy whole-body irradiation in mice almost completely prevented the splenic damage. It could significantly enhance the splenic antioxidant activity which kept the number of splenic white pulp and consequently resisted the shrinkage of the spleen. Moreover, the thymus index, hepatic antioxidant activity, and white blood cell (WBC) count of peripheral blood in irradiated mice pretreated with GST-TAT-SOD also remarkably increased. Although the treated and untreated irradiated mice showed no significant difference in the growth rate of animal body weight at 7 days postirradiation, the highest growth rate of body weight was observed in the GST-TAT-SOD-pretreated group. Furthermore, GST-TAT-SOD pretreatment increased resistance against 8 Gy whole-body irradiation and enhanced 30 d survival. The overall effect of GST-TAT-SOD seemed to be a bit more powerful than that of amifostine. In conclusion, GST-TAT-SOD would be a safe and potentially promising radioprotector.

Biology of Oscillatoria cf. chalybea, a 2-methylisoborneol producing blue-green alga of Mississippi catfish ponds

1995 ◽  
Vol 31 (11) ◽  
pp. 173-180 ◽  
Author(s):  
M. van der Ploeg ◽  
M. E. Dennis ◽  
M. Q. de Regt
Keyword(s):  
Growth Rate ◽  
Specific Growth ◽  
Light Availability ◽  
Continuous Light ◽  
Light Cycle ◽  
Blue Green Alga ◽  
Continuous Cultures ◽  
Effects Of Temperature ◽  
Catfish Ponds ◽  
Specific Growth Rates

Relative abundance of Oscillatoria cf. chalybea was monitored during May-November, 1993, in 40 ponds at four catfish farms located 50-100 km apart in west central Mississippi, USA. The occurrence of O. cf.chalybea coincided with the period that water temperatures remained above 20°C. In 70% of ponds, O. cf.chalybea was present for a period of 2-20 weeks. The alga recurred in all ponds where it had been present in 1990 and 1991. The effects of temperature and light availability on growth rate and 2-methylisoborneol (MIB) production of O. cf. chalybea were studied in continuous cultures. At 28°C, maximum specific growth rates were 0.8 d−1 (24 h light) and 0.6 d−1 (14 h light :10 h dark). Algal cells contained less MIB when adapted to the shorter light cycle than when grown under continuous light. Specific growth rate of O. cf.chalybea dropped from 0.3 to 0.1 d−1 when temperature was changed from 21 to 19.5°C (14 h light).

Zebrafish semaphorin Z1a collapses specific growth cones and alters their pathway in vivo

Development ◽  
1998 ◽  
Vol 125 (7) ◽  
pp. 1275-1283 ◽  
Author(s):  
W. Shoji ◽  
C.S. Yee ◽  
J.Y. Kuwada
Keyword(s):  
Sensory Neurons ◽  
Lateral Line ◽  
Knockout Mice ◽  
Specific Growth ◽  
Transmembrane Proteins ◽  
Growth Cones ◽  
In Vitro Activity ◽  
Different Strains

The semaphorin/collapsin gene family encodes secreted and transmembrane proteins several of which can repulse growth cones. Although the in vitro activity of Semaphorin III/D/Collapsin 1 is clear, recent analyses of two different strains of semaphorin III/D/collapsin 1 knockout mice have generated conflicting findings. In order to clarify the in vivo action of this molecule, we analyzed sema Z1a, a zebrafish homolog of semaphorin III/D/collapsin 1. The expression pattern of sema Z1a suggested that it delimited the pathway of the growth cones of a specific set of sensory neurons, the posterior ganglion of the lateral line, in zebrafish. To examine the in vivo action of this molecule, we analyzed (1) the pathways followed by lateral line growth cones in mutants in which the expression of sema Z1a is altered in an interesting way, (2) response of lateral line growth cones to exogenous Sema Z1a in living embryos, and (3) the pathway followed by lateral line growth cones when Sema Z1a is misexpressed by cells along their normal route. The results suggest that a repulsive action of Sema Z1a helps guide the growth cones of the lateral line along their normal pathway.

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