A histological study of early chondrification in Malathion-treated chick embryos, with emphasis on cell numbers, cell size, and patterns of matrix deposition

1977 ◽  
Vol 55 (9) ◽  
pp. 1515-1522 ◽  
Author(s):  
S. B. Jackson ◽  
M. A. Gibson
Keyword(s):  
Growth Rate ◽  
Cell Size ◽  
Unit Area ◽  
Histological Study ◽  
Cell Activity ◽  
Histochemical Staining ◽  
Ground Substance ◽  
Chick Embryos ◽  
Cell Numbers ◽  
Matrix Deposition

Chick embryos were given a teratogenic dose of Malathion at the 5-day incubation stage and its effects on the early histogenesis of the tibiotarsus were studied during the 8- to 20-day incubation period. This investigation included studies of the growth rate as indicated by mitotic index and the number of cells per unit area, of cell activity as indicated by cell size and the amount of matrix per cell, and of matrix formation as indicated by rates of deposition and erosion and by histochemical staining. The Malathion caused an increased proliferation of the chondroblasts during the initial chondrification stages only. It led to an increase in the number and size of the chondrocytes, particularly in areas of reduced matrix deposition. The Malathion primarily influenced the deposition of the ground substance, causing: (1) a reduction in the amount of ground substance deposited, (2) a reduction in the degree of sulfation and polymerization of that ground substance which was deposited, and (3) a lysosomal-mediated resorption of the formed matrix along the epiphyseal–diaphyseal border. In these ways, the Malathion causes a reduction in the growth rate of the tibiotarsus and a weakening of the cartilage model which subsequently results in a bending of the tibiotarsus.

scholarly journals The Abundance of Microcystin-Producing Genotypes Correlates Positively with Colony Size in Microcystis sp. and Determines Its Microcystin Net Production in Lake Wannsee

2003 ◽  
Vol 69 (2) ◽  
pp. 787-795 ◽  
Author(s):  
Rainer Kurmayer ◽  
Guntram Christiansen ◽  
Ingrid Chorus
Keyword(s):  
Growth Rate ◽  
Colony Size ◽  
Population Growth Rate ◽  
Size Class ◽  
Net Production ◽  
Cell Numbers ◽  
Size Classes ◽  
Key Factor ◽  
Genotype Composition ◽  
Working Hypotheses

ABSTRACT The working hypotheses tested on a natural population of Microcystis sp. in Lake Wannsee (Berlin, Germany) were that (i) the varying abundance of microcystin-producing genotypes versus non-microcystin-producing genotypes is a key factor for microcystin net production and (ii) the occurrence of a gene for microcystin net production is related to colony morphology, particularly colony size. To test these hypotheses, samples were fractionated by colony size with a sieving procedure during the summer of 2000. Each colony size class was analyzed for cell numbers, the proportion of microcystin-producing genotypes, and microcystin concentrations. The smallest size class of Microcystis colonies (<50 μm) showed the lowest proportion of microcystin-producing genotypes, the highest proportion of non-microcystin-producing cells, and the lowest microcystin cell quotas (sum of microcystins RR, YR, LR, and WR). In contrast, the larger size classes of Microcystis colonies (>100 μm) showed the highest proportion of microcystin-producing genotypes, the lowest proportion of non-microcystin-producing cells, and the highest microcystin cell quotas. The microcystin net production rate was nearly one to one positively related to the population growth rate for the larger colony size classes (>100 μm); however, no relationship could be found for the smaller size classes. It was concluded that the variations found in microcystin net production between colony size classes are chiefly due to differences in genotype composition and that the microcystin net production in the lake is mainly influenced by the abundance of the larger (>100-μm) microcystin-producing colonies.

Cambial activity and ray cell abundance in Acer saccharum

1977 ◽  
Vol 55 (20) ◽  
pp. 2559-2564 ◽  
Author(s):  
R. A. Gregory
Keyword(s):  
Growth Rate ◽  
Acer Saccharum ◽  
Unit Area ◽  
Ring Width ◽  
Cambial Activity ◽  
Relative Volume ◽  
Annual Ring Width ◽  
Ray Cells ◽  
Fusiform Initials ◽  
Ray Cell

The ratio of ray and ray cell initials to fusiform initials of the vascular cambium relative to radial growth rate as reflected in the secondary xylem was studied in stems of Acer saccharum Marsh. Ray initials increased in size as they aged, slowly when growth rate was low, rapidly when it was high, but there was little fluctuation in the number of rays per unit of tangential area; as the cambium increased in circumference, the older, larger rays diverged and new small rays arose in intervening areas, thus maintaining a uniform unit area population independent of growth rate. However, since ray size increased rapidly when growth rate was high, the unit area population of ray cells rose abruptly with accelerating growth rate: the relative volume of xylem ray tissue rose from 8.6 to 12.7% of the total xylem volume when annual ring width increased from 1 to 7 mm. When fast growth was not maintained, the unit area population of ray cells declined slowly as the large rays diverged.

Age and sex do not affect the volume, cell numbers, or cell size of the suprachiasmatic nucleus of the rat: An unbiased stereological study

1995 ◽  
Vol 361 (4) ◽  
pp. 585-601 ◽  
Author(s):  
M. Dulce Madeira ◽  
N. Sousa ◽  
R. M. Santer ◽  
M. M. Paula-Barbosa ◽  
H. J. G. Gundersen
Keyword(s):  
Cell Size ◽  
Suprachiasmatic Nucleus ◽  
Cell Numbers ◽  
Volume Cell ◽  
Age And Sex

The role of ultimobranchial bodies in the modulation of the response of chick embryos to 1,25-dihydroxycholecalciferol

Development ◽  
1986 ◽  
Vol 97 (1) ◽  
pp. 87-94
Author(s):  
Roberto Narbaitz ◽  
Jaffar Soleimani Rad
Keyword(s):  
Bone Resorption ◽  
Ethyl Alcohol ◽  
Inorganic Phosphate ◽  
Histological Study ◽  
Chorioallantoic Membrane ◽  
Chick Embryos ◽  
Series Of Experiments ◽  
Ultrastructural Characteristics ◽  
Bone Trabeculae

Ultimobranchial bodies (UBBs) were dissected from 17-day-old chick embryos and grafted onto the chorioallantoic membrane of 8-day-old embryos. The embryos with UBB grafts as well as sham-grafted controls were injected on the 10th day of incubation with 100 ng 1,25(OH)2D3 dissolved in ethyl alcohol or with an equal volume of ethyl alcohol alone; embryos were sacrificed on the 13th day. Grafted UBBs showed ultrastructural characteristics typical of actively secreting glands. A histological study of the tibiae from all embryos showed that while the grafted embryos responded to the injection of 1,25(OH)2D3 with a peripheral rim of undermineralized bone trabeculae, sham-grafted embryos never did so. These results confirm the original hypothesis that the presence of differentiated UBBs is a precondition for the production of undermineralized bone (osteoid) by 1,25(OH)2D3. In a second series of experiments, similarly treated embryos were sacrificed on the 10th, 11th, 12th and 13th day; the levels of calcium and inorganic phosphate were determined in their blood. The injection of 1,25(OH)2D3 produced in all embryos hypercalcaemia and hypophosphataemia. However, the hypophosphataemic response was more prolonged in the embryos with UBB grafts than in sham-grafted ones. These results suggest that the grafted UBBs prolonged the hypophosphataemic response, probably by secreting calcitonin and thus reducing the rate of bone resorption. It is also probable that the prolonged hypophosphataemia produced or contributed to the undermineralization of the peripheral (subperiosteal) trabeculae.

scholarly journals Covariation of metabolic rates and cell size in coccolithophores

2015 ◽  
Vol 12 (15) ◽  
pp. 4665-4692 ◽  
Author(s):  
G. Aloisi
Keyword(s):  
Growth Rate ◽  
Environmental Change ◽  
Cell Size ◽  
Environmental Conditions ◽  
Laboratory Experiments ◽  
Opposite Effect ◽  
Cell Structure ◽  
Metabolic Rates ◽  
The Future ◽  
Phytoplankton Group

Abstract. Coccolithophores are sensitive recorders of environmental change. The size of their coccosphere varies in the ocean along gradients of environmental conditions and provides a key for understanding the fate of this important phytoplankton group in the future ocean. But interpreting field changes in coccosphere size in terms of laboratory observations is hard, mainly because the marine signal reflects the response of multiple morphotypes to changes in a combination of environmental variables. In this paper I examine the large corpus of published laboratory experiments with coccolithophores looking for relations between environmental conditions, metabolic rates and cell size (a proxy for coccosphere size). I show that growth, photosynthesis and, to a lesser extent, calcification covary with cell size when pCO2, irradiance, temperature, nitrate, phosphate and iron conditions change. With the exception of phosphate and temperature, a change from limiting to non-limiting conditions always results in an increase in cell size. An increase in phosphate or temperature (below the optimum temperature for growth) produces the opposite effect. The magnitude of the coccosphere-size changes observed in the laboratory is comparable to that observed in the ocean. If the biological reasons behind the environment–metabolism–size link are understood, it will be possible to use coccosphere-size changes in the modern ocean and in marine sediments to investigate the fate of coccolithophores in the future ocean. This reasoning can be extended to the size of coccoliths if, as recent experiments are starting to show, coccolith size reacts to environmental change proportionally to coccosphere size. The coccolithophore database is strongly biased in favour of experiments with the coccolithophore Emiliania huxleyi (E. huxleyi; 82 % of database entries), and more experiments with other species are needed to understand whether these observations can be extended to coccolithophores in general. I introduce a simple model that simulates the growth rate and the size of cells forced by nitrate and phosphate concentrations. By considering a simple rule that allocates the energy flow from nutrient acquisition to cell structure (biomass) and cell maturity (biological complexity, eventually leading to cell division), the model is able to reproduce the covariation of growth rate and cell size observed in laboratory experiments with E. huxleyi when these nutrients become limiting. These results support ongoing efforts to interpret coccosphere and coccolith size measurements in the context of climate change.

The effect of cell size on cellular Zn and Cd and Zn‐Cd‐CO 2 colimitation of growth rate in marine diatoms

2020 ◽  
Vol 65 (12) ◽  
pp. 2896-2911
Author(s):  
Weiying Li ◽  
William G. Sunda ◽  
Wenfang Lin ◽  
Haizheng Hong ◽  
Dalin Shi
Keyword(s):  
Growth Rate ◽  
Cell Size ◽  
Marine Diatoms

scholarly journals Biphasic Cell-Size and Growth-Rate Homeostasis by Single Bacillus subtilis Cells

2020 ◽  
Vol 30 (12) ◽  
pp. 2238-2247.e5 ◽  
Author(s):  
Niclas Nordholt ◽  
Johan H. van Heerden ◽  
Frank J. Bruggeman
Keyword(s):  
Growth Rate ◽  
Bacillus Subtilis ◽  
Cell Size
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