The behaviour of fibroblasts migrating from chick heart explants: changes in adhesion, locomotion and growth, and in the distribution of actomyosin and fibronectin

1979 ◽  
Vol 39 (1) ◽  
pp. 149-165
Author(s):  
J.R. Couchman ◽  
D.A. Rees
Keyword(s):  
Growth Rate ◽  
Focal Adhesions ◽  
High Rate ◽  
Chick Embryos ◽  
Focal Contacts ◽  
Parallel Increase ◽  
Fibronectin Expression ◽  
Chick Heart ◽  
High Degree

Fibroblasts migrating from heart explants of chick embryos at first have a high rate of locomotion but lack focal contacts or adhesions and also lack substantial actin-containing bundles. A meshwork of 7-nm filaments is present particularly in submembranous regions and is proposed to be directed towards efficient locomotion whilst maintaining a high degree of spreading. Also during the first 48 h there is little production of extracellular fibronectin and the growth rate is low. Later, these fibroblasts develop focal contacts and focal adhesions together with actomyosin bundles, with a parallel increase in fibronectin expression. We propose that progressive immobilization by the development of focal adhesions and actomyosin structures occurs to set these cells up for growth.

scholarly journals Fibronectin has a dual role in locomotion and anchorage of primary chick fibroblasts and can promote entry into the division cycle.

1982 ◽  
Vol 93 (2) ◽  
pp. 402-410 ◽  
Author(s):  
J R Couchman ◽  
D A Rees ◽  
M R Green ◽  
C G Smith
Keyword(s):  
Focal Adhesion ◽  
Focal Adhesions ◽  
Growth Cycle ◽  
Culture Conditions ◽  
Biological Functions ◽  
Macromolecular Synthesis ◽  
Natural Factor ◽  
Motile Cells ◽  
Chick Heart ◽  
Gold Marker

Fibronectin (FN), which is already known to be a natural factor for fibroblast spreading on substrata, has now been shown to be essential for two distinct types of adhesion with different biological functions in chick heart fibroblasts, namely adhesion directed toward locomotion and toward stationary anchorage for growth. Manipulation of culture conditions and the use of antisera of differing specificities has demonstrated that both exogenous and cell-derived FN are important in each process. The organization of the fibronectin-containing matrix differs between the two states. Immunoelectron microscopy with a colloidal gold marker reveals the presence of small membrane-associated plaques of fibronectin in motile cells with associated submembranous specialization. A fibrillar matrix containing fibronectin is dominant in nonmotile, growing fibroblasts. The development of focal adhesions for stationary anchorage can be dramatically enhanced by addition of cell-derived FN at an appropriate stage, and this promotes entry into the growth cycle. New macromolecular synthesis in addition to FN is necessary for focal adhesion development but not for locomotion.

scholarly journals The rooting, survival and growth of woody species on tailing dumps in the limestone quarry “Lafarge ciment”

2021 ◽  
Vol 13 (1(22)) ◽  
pp. 34-42
Author(s):  
Petru Cuza ◽  
◽  
Corina Certan ◽  
Constantin Bulimaga ◽  
◽  
...  
Keyword(s):  
Growth Rate ◽  
Environmental Factors ◽  
Slow Growth ◽  
Woody Species ◽  
Mineral Elements ◽  
Black Pine ◽  
Limestone Quarry ◽  
Survival And Growth ◽  
High Degree ◽  
Fast Growing Species

The rooting, the survival and dynamics of growths in the height and after the diameter of the seedlings, of a range of woody species, had investigated on the freshly formed sterile dump limestone quarry „Lafarge Ciment”. The seedlings of the woody species had a relatively good rooting (69-99%). A high degree of rooting can be ensured as a result of the maintenance of forest crops. After planting, the young seedlings must be cared for by hoeing as many times as necessary in order to control the weeds and maintain moisture in the soil, which increases the survival of the seedlings. Tree species have been characterized by a different growth rate. Acacia has showed a very rapid increase in height, but the black pine has been characterized by a slow growth. Acacia being a fast-growing species and unpretentious to the mineral elements in the soil can be used to afforest the limestone quarry land. In the fi rst year after planting, the young seedlings, otherwise sensitive to the action of the environmental factors, had an increase in height and in diameter slow and uneven. In the years that followed, the seedlings became more viable and less infl uenced by local and temporal fl uctuations of environmental factors.

High rate growth of device grade silicon thin films for solar cells

2001 ◽  
Vol 664 ◽  
Author(s):  
M. Kondo ◽  
S. Suzuki ◽  
Y. Nasuno ◽  
A. Matsuda
Keyword(s):  
Growth Rate ◽  
Solar Cells ◽  
Defect Density ◽  
Chemical Vapor ◽  
High Growth ◽  
Ion Bombardment ◽  
High Rate ◽  
Limiting Factors ◽  
Material Quality ◽  
Deuterium Dilution

ABSTRACTWe have developed a plasma enhanced chemical vapor deposition (PECVD) technique for high-rate growth of µc-Si:H at low temperatures using hydrogen diluted monosilane source gas under high-pressure depletion conditions. It was found that material qualities deteriorate, e.g. crystallinity decreases and defect density increases with increasing growth rate mainly due to ion damage from the plasma. We have found that deuterium dilution improves not only the crystallinity but also defect density as compared to hydrogen dilution and that deuterium to hydrogen ratio incorporated in the film has a good correlation with crystallinity. The advantages of the deuterium dilution are ascribed to lower ion bombardment due to slower ambipolar diffusion of deuterium ion from the plasma. Further improvement of material quality has been achieved using a triode technique where a mesh electrode inserted between cathode and anode electrodes prevents from ion bombardment. In combination with a shower head cathode, the triode technique remarkably improves the crystallinity as well as defect density at a high growth rate. As a consequence, we have succeeded to obtain much better crystallinity and uniformity at 5.8 nm/s with a defect density of 2.6×1016cm−3. We also discuss the limiting factors of growth rate and material quality for µc-Si solar cells.

Control of Materials and Interfaces in μc-Si:H-based Solar Cells Grown at High Rate

2011 ◽  
Vol 1321 ◽  
Author(s):  
Yasushi Sobajima ◽  
Chitose Sada ◽  
Akihisa Matsuda ◽  
Hiroaki Okamoto
Keyword(s):  
Growth Rate ◽  
Solar Cells ◽  
Film Growth ◽  
Defect Density ◽  
Density Measurement ◽  
High Growth ◽  
High Growth Rate ◽  
High Rate ◽  
Bulk Region ◽  
Dangling Bond

ABSTRACTGrowth process of microcrystalline silicon (μc-Si:H) using plasma-enhanced chemicalvapor- deposition method under high-rate-growth condition has been studied for the control of optoelectronic properties in the resulting materials. We have found two important things for the spatial-defect distribution in the resulting μc-Si:H through a precise dangling-bond-density measurement, e. g., (1) dangling-bond defects are uniformly distributed in the bulk region of μc- Si:H films independent of their crystallite size and (2) large number of dangling bonds are located at the surface of μc-Si:H especially when the film is deposited at high growth rate. Starting procedure of film growth has been investigated as an important process to control the dangling-bond-defect density in the bulk region of resulting μc-Si:H through the change in the electron temperature by the presence of particulates produced at the starting period of the plasma. Deposition of Si-compress thin layer on μc-Si:H grown at high rate followed by thermal annealing has been proposed as an effective method to reduce the defect density at the surface of resulting μc-Si:H. Utilizing the starting-procedure-controlling method and the compress-layerdeposition method together with several interface-controlling methods, we have demonstrated the fabrication of high conversion-efficiency (9.27%) substrate-type (n-i-p) μc-Si:H solar cells whose intrinsic μc-Si:H layer is deposited at high growth rate of 2.3 nm/sec.

Mineralogical composition of the clay fraction of two fluvio-glacial sediments from east Greenland

Clay Minerals ◽  
1980 ◽  
Vol 15 (2) ◽  
pp. 135-145 ◽  
Author(s):  
L. Petersen ◽  
K. Rasmussen
Keyword(s):  
Clay Fraction ◽  
Mineralogical Composition ◽  
Cold Climate ◽  
High Rate ◽  
Degree Of Crystallinity ◽  
Metamorphic Rocks ◽  
Glacial Sediments ◽  
East Greenland ◽  
Soil Clays ◽  
High Degree

AbstractThe < 2 µm fractions of two fluvio-glacial sediments from East Greenland have been analysed chemically and by XRD and Mössbauer spectroscopy. The bulk of each < 2 µm fraction consists of feldspars and micas (biotite) which are important constituents of the Precambrian igneous and metamorphic rocks of the area. Significant amounts of vermiculitic and smectitic minerals are also present. Compared with similar minerals present in Danish soil clays, the Greenland vermiculite and smectite are characterized by a high degree of crystallinity and it is concluded that these minerals have been formed from biotite through K release and lattice expansion. These processes appear to have proceeded at a sufficiently high rate to yield significant amounts of vermiculite and smectite despite the cold climate prevailing in the area.

scholarly journals DNA Strand Break-Sensing Molecule Poly(ADP-Ribose) Polymerase Cooperates with p53 in Telomere Function, Chromosome Stability, and Tumor Suppression

2001 ◽  
Vol 21 (12) ◽  
pp. 4046-4054 ◽  
Author(s):  
Wei-Min Tong ◽  
M. Prakash Hande ◽  
Peter M. Lansdorp ◽  
Zhao-Qi Wang
Keyword(s):  
Strand Break ◽  
Cell Cycle Checkpoints ◽  
High Rate ◽  
Loss Of Function ◽  
Li Fraumeni Syndrome ◽  
Dna Strand Break ◽  
Telomere Function ◽  
Dna Strand ◽  
High Degree ◽  
Mutant Cells

ABSTRACT Genomic instability is often caused by mutations in genes that are involved in DNA repair and/or cell cycle checkpoints, and it plays an important role in tumorigenesis. Poly(ADP-ribose) polymerase (PARP) is a DNA strand break-sensing molecule that is involved in the response to DNA damage and the maintenance of telomere function and genomic stability. We report here that, compared to single-mutant cells, PARP and p53 double-mutant cells exhibit many severe chromosome aberrations, including a high degree of aneuploidy, fragmentations, and end-to-end fusions, which may be attributable to telomere dysfunction. While PARP−/− cells showed telomere shortening and p53−/− cells showed normal telomere length, inactivation of PARP in p53−/− cells surprisingly resulted in very long and heterogeneous telomeres, suggesting a functional interplay between PARP and p53 at the telomeres. Strikingly, PARP deficiency widens the tumor spectrum in mice deficient in p53, resulting in a high frequency of carcinomas in the mammary gland, lung, prostate, and skin, as well as brain tumors, reminiscent of Li-Fraumeni syndrome in humans. The enhanced tumorigenesis is likely to be caused by PARP deficiency, which facilitates the loss of function of tumor suppressor genes as demonstrated by a high rate of loss of heterozygosity at the p53 locus in these tumors. These results indicate that PARP and p53 interact to maintain genome integrity and identify PARP as a cofactor for suppressing tumorigenesis.

scholarly journals Genomic analysis of coxsackieviruses A1, A19, A22, enteroviruses 113 and 104: viruses representing two clades with distinct tropism within enterovirus C

2013 ◽  
Vol 94 (9) ◽  
pp. 1995-2004 ◽  
Author(s):  
Rafal Tokarz ◽  
Saddef Haq ◽  
Stephen Sameroff ◽  
Stephen R. C. Howie ◽  
W. Ian Lipkin
Keyword(s):  
Phylogenetic Analysis ◽  
Sequence Analysis ◽  
Genomic Analysis ◽  
The Other ◽  
High Rate ◽  
Structural Genes ◽  
Genome Sequences ◽  
Capsid Region ◽  
High Degree ◽  
Degree Of Similarity

Coxsackieviruses (CV) A1, CV-A19 and CV-A22 have historically comprised a distinct phylogenetic clade within Enterovirus (EV) C. Several novel serotypes that are genetically similar to these three viruses have been recently discovered and characterized. Here, we report the coding sequence analysis of two genotypes of a previously uncharacterized serotype EV-C113 from Bangladesh and demonstrate that it is most similar to CV-A22 and EV-C116 within the capsid region. We sequenced novel genotypes of CV-A1, CV-A19 and CV-A22 from Bangladesh and observed a high rate of recombination within this group. We also report genomic analysis of the rarely reported EV-C104 circulating in the Gambia in 2009. All available EV-C104 sequences displayed a high degree of similarity within the structural genes but formed two clusters within the non-structural genes. One cluster included the recently reported EV-C117, suggesting an ancestral recombination between these two serotypes. Phylogenetic analysis of all available complete genome sequences indicated the existence of two subgroups within this distinct Enterovirus C clade: one has been exclusively recovered from gastrointestinal samples, while the other cluster has been implicated in respiratory disease.

India's Agricultural Exports

2000 ◽  
Vol 35 (1) ◽  
pp. 32-46 ◽  
Author(s):  
S.K. Goyal ◽  
R.N. Pandey ◽  
J.P. Singh
Keyword(s):  
Growth Rate ◽  
High Rate ◽  
Agricultural Exports ◽  
Rate Of Growth ◽  
Oil Cakes ◽  
The World ◽  
High Volatility ◽  
Marine Products ◽  
Coffee Oil ◽  
Manufactured Exports

The composition of Indian exports indicated the rising share of manufactured exports and the decline of agricultural exports. Of the various agricultural & allied items, tea & mate, cashew kernels, spices and coffee were the dominant exportable items during 1970s but their share later on had declined. Further it was found that during the nineties, marine products, oil cakes, rice, fruits, etc. have potential for export earnings. The total agricultural exports increased at the annual compound growth rate of about 25 per cent during 1991-98. The compound growth rate of all the agricultural and allied items except tea & mate and sugar & honey were higher during nineties (1991-98) than in seventies and eighties. During this period (1991-98), coffee, oil cakes, tobacco, raw cotton, rice, spices and fish & products exhibited high volatility in exports. The share of our agricultural exports in world exports although is very low but is increasing over the years. For competing with other countries and, therefore, to raise its share in the world exports, sustained high rate of growth of Indian exports is of paramount importance. The prospects for increasing agricultural exports have improved after the liberalisation.

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