A quantitative analysis of the effect of excision of the AER from the chick limb-bud

Development ◽  
1974 ◽  
Vol 32 (3) ◽  
pp. 651-660
Author(s):  
Dennis Summerbell
Keyword(s):  
Quantitative Analysis ◽  
Quantitative Method ◽  
Continuous Process ◽  
Apical Ectodermal Ridge ◽  
Rate Of Change ◽  
Limb Bud ◽  
Zone Model ◽  
Gradual Change ◽  
Analysis Of Results ◽  
Positional Value

The effect of removal of the apical ectodermal ridge from the early chick limb-bud is re-examined using a new quantitative method of analysis of results. The concept of the proximo-distal sequence of laying down of parts is confirmed and evidence is presented thatthis proceeds as a continuous process, there being a gradual change in the level specified from one cell to another at a more distal level. The results are then interpreted in terms of the ‘progress zone’ model to show that they are both consistent with the model and that they provide an assay for one of its parameters, the rate of change of positional value with time at the tip.

Interaction between the proximo-distal and antero-posterior co-ordinates of positional value during the specification of positional information in the early development of the chick limb-bud

Development ◽  
1974 ◽  
Vol 32 (1) ◽  
pp. 227-237
Author(s):  
Dennis Summerbell
Keyword(s):  
Early Development ◽  
Anterior Margin ◽  
Positional Information ◽  
Apical Ectodermal Ridge ◽  
Limb Bud ◽  
Anteroposterior Axis ◽  
Zone Of Polarizing Activity ◽  
Positional Value ◽  
Special Region

The experiments examine the extent of reduplication of skeletal parts across the anteroposterior axis, following the transplantation of a zone of polarizing activity (ZPA) to the anterior margin of the limb-bud at successively later stages. Previous studies have suggested that the function of the apical ectodermal ridge (AER) is to maintain cells in a special region at the distal tip (the progress zone) labile, with respect to their positional value along the proximo-distal axis. Similarly, the results of these experiments demonstrate that cells in the progress zone are able to change their antero-posterior positional value under the influence of the grafted ZPA, while cells at more proximal levels remain unaffected. In turn, the ZPA may effect the activity of the AER and hence the progress zone.

The effect of cell killing by X-irradiation on pattern formation in the chick limb

Development ◽  
1979 ◽  
Vol 50 (1) ◽  
pp. 175-198
Author(s):  
L. Wolpert ◽  
C. Tickle ◽  
M. Sampford ◽  
J. H. Lewis
Keyword(s):  
Quantitative Analysis ◽  
Pattern Formation ◽  
Positional Information ◽  
Limb Bud ◽  
Zone Model ◽  
Viable Cells ◽  
Dividing Cells ◽  
X Irradiation ◽  
Mesenchyme Cells ◽  
Number Of Cells

It has been suggested that positional information along the proximo-distal axis of the limb-bud is specified by time spent in the progress zone. Mesenchyme cells have been killed by X-irradiation, reducing the rate cells leave the zone. The time spent there by some cells is thus increased. When limbs, stage 18/19, stage 21, or tips of stage 24, are treated with increasing doses of X-irradiation, from 1000 rads to 2500 rads proximal structures are progressively lost, whereas distal ones— the digits—are relatively unaffected. There was no evidence for intercalation of missing parts. These effects are due to killing or damage of mesenchyme cells: the ectoderm is not affected at these doses. The results are consistent with a quantitative analysis based on the progress zone model, in which viable cells repopulate the progress zone and gradually restore it to normal as non-dividing cells are diluted out. It is suggested that any treatment causing damage to the mesenchyme at early stages will give similar results. The mesenchyme cells appear to be surprisingly resistant to radiation damage. The form of the limb-bud is not altered by damaging the mesenchyme. Differences in the development of structures at similar proximo-distal levels, following irradiation, is considered in terms of the requirement of a threshold number of cells.

Time, place and positional value in the chick limb-bud

Development ◽  
1975 ◽  
Vol 33 (3) ◽  
pp. 621-643
Author(s):  
D. Summerbell ◽  
J. H. Lewis
Keyword(s):  
Experimental Evidence ◽  
Long Range ◽  
Limb Development ◽  
Apical Ectodermal Ridge ◽  
Limb Bud ◽  
Timing Mechanism ◽  
Positional Value

Quantitative experimental evidence is presented for the progress zone theory of limb development. The theory, here formulated mathematically, states that the parts of the limb are specified in proximo-distal succession by an autonomous timing mechanism operating in a ‘progress zone’ of undifferentiated growing mesenchyme under the influence of the apical ectodermal ridge. By the exchange of distal tips between young and old wing-buds, it is shown that there are no long-range morphogenetic signals from proximal to distal tissue. The width of the progress zone is calculated, and it is found autoradiographically that practically all its cells are dividing.

scholarly journals Determination of Flavonoids Compounds of Three Species and Different Harvesting Periods in Crataegi folium Based on LC-MS/MS

Molecules ◽  
2021 ◽  
Vol 26 (6) ◽  
pp. 1602
Author(s):  
Ya-Ping Guo ◽  
Hong Yang ◽  
Ya-Li Wang ◽  
Xiao-Xiang Chen ◽  
Ke Zhang ◽  
...  
Keyword(s):  
Quantitative Analysis ◽  
Qualitative Analysis ◽  
Quantitative Method ◽  
Total Content ◽  
Qualitative And Quantitative Analysis ◽  
Pharmacological Activities ◽  
Time Saving ◽  
Qualitative And Quantitative ◽  
First Time

Crataegi folium have been used as medicinal and food materials worldwide due to its pharmacological activities. Although the leaves of Crataegus songorica (CS), Crataegus altaica (CA) and Crataegus kansuensis (CK) have rich resources in Xinjiang, China, they can not provide insights into edible and medicinal aspects. Few reports are available on the qualitative and quantitative analysis of flavonoids compounds of their leaves. Therefore, it is necessary to develop efficient methods to determine qualitative and quantitative flavonoids compounds in leaves of CS, CA and CK. In the study, 28 unique compounds were identified in CS versus CK by qualitative analysis. The validated quantitative method was employed to determine the content of eight flavonoids of the leaves of CS, CA and CK within 6 min. The total content of eight flavonoids was 7.8–15.1 mg/g, 0.1–9.1 mg/g and 4.8–10.7 mg/g in the leaves of CS, CA and CK respectively. Besides, the best harvesting periods of the three species were from 17th to 26th September for CS, from 30th September to 15th October for CA and CK. The validated and time-saving method was successfully implemented for the analysis of the content of eight flavonoids compounds in CS, CA and CK for the first time.

FGF-4 maintains polarizing activity of posterior limb bud cells in vivo and in vitro

Development ◽  
1993 ◽  
Vol 119 (1) ◽  
pp. 199-206 ◽  
Author(s):  
A. Vogel ◽  
C. Tickle
Keyword(s):  
Posterior Margin ◽  
Anterior Margin ◽  
Marked Decrease ◽  
Mesenchymal Cells ◽  
Apical Ectodermal Ridge ◽  
Limb Bud ◽  
Posterior Limb ◽  
Vertebrate Limb

The polarizing region is a major signalling tissue involved in patterning the tissues of the vertebrate limb. The polarizing region is located at the posterior margin of the limb bud and can be recognized by its ability to induce additional digits when grafted to the anterior margin of a chick limb bud. The signal from the polarizing region operates at the tip of the bud in the progress zone, a zone of undifferentiated mesenchymal cells, maintained by interactions with the apical ectodermal ridge. A number of observations have pointed to a link between the apical ectodermal ridge and signalling by the polarizing region. To test this possibility, we removed the posterior apical ectodermal ridge of chick wing buds and assayed posterior mesenchyme for polarizing activity. When the apical ectodermal ridge is removed, there is a marked decrease in polarizing activity of posterior cells. The posterior apical ectodermal ridge is known to express FGF-4 and we show that the decrease in polarizing activity of posterior cells of wing buds that normally follows ridge removal can be prevented by implanting a FGF-4-soaked bead. Furthermore, we show that both ectoderm and FGF-4 maintain polarizing activity of limb bud cells in culture.

Myogenic cell movement in the developing avian limb bud in presence and absence of the apical ectodermal ridge (AER)

Development ◽  
1984 ◽  
Vol 80 (1) ◽  
pp. 105-125
Author(s):  
Madeleine Gumpel-Pinot ◽  
D. A. Ede ◽  
O. P. Flint
Keyword(s):  
Cell Migration ◽  
Cell Movement ◽  
Host Tissue ◽  
Apical Ectodermal Ridge ◽  
Limb Bud ◽  
Myogenic Cell ◽  
Myogenic Cells ◽  
Apical Direction ◽  
Wing Bud ◽  
Presence And Absence

Fragments of quail wing bud containing myogenic cells of somitic origin and fragments of quail sphlanchopleural tissue were introduced into the interior of the wing bud of fowl embryo hosts. No movement of graft into host tissue occurred in the control, but myogenic cells from the quail wing bud fragments underwent long migrations in an apical direction to become incorporated in the developing musculature of the host. When the apical ectodermal ridge (AER), together with some subridge mesenchyme, was removed at the time of grafting, no such cell migration occurred. The capacity of grafted myogenic cells to migrate in the presence of AER persists to H.H. stage 25, when myogenesis has begun, but premyogenic cells in the somites, which normally migrate out into the early limb bud, do not migrate when somite fragments are grafted into the wing bud. Coelomic grafts of apical and proximal wing fragments showed that apical sections of quail wing buds become invaded by myogenic cells of the host, but grafts from proximal wing bud regions do not.

Apical ectodermal ridge induction by the transplantation of En-1-overexpressing ectoderm in chick limb bud

1998 ◽  
Vol 40 (4) ◽  
pp. 423-429 ◽  
Author(s):  
Mikiko Tanaka ◽  
Yasuyo Shigetani ◽  
Sayaka Sugiyama ◽  
Koji Tamura ◽  
Harukazu Nakamura ◽  
...  
Keyword(s):  
Apical Ectodermal Ridge ◽  
Limb Bud

EFFECTS OF HIGH RATES OF NITROGEN ON NEEPAWA WHEAT GROWN UNDER IRRIGATION. III. PROTEIN QUALITY FOR BREADMAKING AS REFLECTED BY VARIOUS TESTS

1978 ◽  
Vol 58 (4) ◽  
pp. 923-927 ◽  
Author(s):  
W. BUSHUK ◽  
F. J. RODRIGUEZ-BORES ◽  
S. DUBETZ
Keyword(s):  
Protein Content ◽  
Protein Quality ◽  
Protein Solubility ◽  
Triticum Aestivum L ◽  
Rate Of Change ◽  
Composition Analysis ◽  
Loaf Volume ◽  
Gradual Change ◽  
Small Contribution ◽  
Breadmaking Quality

Eleven samples of hard red spring wheat Triticum aestivum L. em Thell cv. Neepawa, selected from a fertilizer–irrigation study and ranging in protein content from 9.3 to 16.4%, were subjected to various breadmaking quality tests, protein solubility fractionation, amino acid composition analysis and gliadin electrophoresis analysis. Loaf volumes showed a decrease in breadmaking quality with increasing protein for samples at the top of the protein content range. Conversely, the Pelshenke and Zeleny Sedimentation values showed a reverse trend in the same region of protein content. Most of the decreasing rate of change in the loaf volume with protein content at the top of the protein range can be explained by the gradual change in solubility of the glutenin. The gradual decrease in the amount of damaged starch can make a small contribution to the observed loss of quality. Minor quantitative differences (slightly stronger stain intensity for a few bands) were observed in the gliadin electrophoregrams of samples of different protein content. There is no obvious explanation for the increasing rate of change in Pelshenke and Zeleny Sedimentation values with protein content at the top of the protein range.

scholarly journals Bandung’s Image as a Tourist Destination: An Application of Quantitative and Qualitative Approach

2019 ◽  
Vol 1 (01) ◽  
Author(s):  
Agustinus Februadi ◽  
Nono Wibisono ◽  
Dewi Purnamasari
Keyword(s):  
Factor Analysis ◽  
Quantitative Analysis ◽  
Quantitative Method ◽  
Qualitative Approach ◽  
Tourist Destination ◽  
Nature Tourism ◽  
Scenic Beauty ◽  
Qualitative And Quantitative ◽  
The Right ◽  
Functional Attribute

Bandung is a popular tourist destination in Indonesia and a gateway for tourists who visit destinations around greater Bandung areas. Currently, Bandung is also known as a culinary, shopping, and nature tourism destination. Past studies have measured the image of Bandung as a tourist destination. However, the measurements were done partially due to the use of quantitative method only. Thus, the results were not comprehensive. To resolve the drawbacks of the previous studies, this study used both qualitative and quantitative approaches. Data were collected from 430 domestic tourists by ways of structured and unstructured interviews in 20 different destinations in Bandung and the surrounding. Data were processed by descriptive statistical methods, factor analysis and content analysis. The results of quantitative analysis show that, in term of functional-attribute, Bandung was positively perceived as a destination characterized with natural scenic beauty, many interesting places, and various exotic foods. In terms of the psychological-attribute, Bandung was perceived as the right place for shopping and culinary tourism. The results of qualitative analysis indicate that, functionally, Bandung was a destination with natural scenic beauty, pleasant weather and provide various exotic foods. Psychologically, the tourists experienced calm and tranquil atmosphere, happiness, and comfort.

scholarly journals ENHANCING STUDENTS' READING ABILITY THROUGH CNA INDONESIA

2020 ◽  
Vol 8 (2) ◽  
pp. 124
Author(s):  
Syahban Mada Ali
Keyword(s):  
Quantitative Analysis ◽  
Reading Ability ◽  
Quantitative Method ◽  
Reading Test ◽  
Post Test ◽  
The Subject

The aim of this research is to find out whether the students’ reading ability improve or not through CNA Indonesia at the fourth semester Students of Tomakaka University of Mamuju. The method was used is quantitative method. The instrument used to collect the data was reading test. The number of test consisted of 15 and the form is multiple choices. The subject of this research was the fourth semester students of Tomakaka University of Mamuju. In analyzing the data collected through quantitative analysis. The result of this research is the use of Channel News Asia (CAN) Indonesia can enhancing the students’ reading ability at the fourth semester students of Tomakaka University of Mamuju. It is supported by the result of the test which given for the students after given treatment. The result showed that there was an improvement significantly between pre-test and post-test

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