scholarly journals STUDIES IN THE BIOLOGY OF METALS

1928 ◽  
Vol 48 (5) ◽  
pp. 659-665 ◽  
Author(s):  
Frederick S. Hammett ◽  
Vilma L. Wallace
Keyword(s):  
Cell Proliferation ◽  
Chick Embryo ◽  
Body Length ◽  
Rapid Growth ◽  
Cell Number ◽  
Point Of View ◽  
Lead Ion ◽  
Head Region ◽  
Differential Development

Our study of the effect of the lead ion on the development of the chick embryo has brought out the following facts: 1. Gross growth is retarded. 2. Somite growth is retarded to a degree greater than that exhibited by body length and width. 3. The head and optic anlagen are regions of particular sensitivity. Their differential development is markedly inhibited. From the purely biological point of view these results are in line with the findings of Child (10) and his school as to the sensitivity of the head end of rapidly growing organisms to harmful influences, and with those of Stockard (11) as to the peculiar sensitivity of the optic anlagen. It is almost too well known to need repetition that the head region and the somites of embryos are specific areas of intense growth by increase in cell number. Therefore, turning from the general to the particular, the differential retardation of these regions which is caused by lead, is evidence justifying the conclusion that it is areas of rapid growth by cell proliferation which are selectively inhibited by this metallic ion.

Bombesin and other growth factors activate cell proliferation in chick embryo otic vesicles in culture

Development ◽  
1988 ◽  
Vol 103 (1) ◽  
pp. 87-96 ◽  
Author(s):  
J.J. Represa ◽  
C. Miner ◽  
E. Barbosa ◽  
F. Giraldez
Keyword(s):  
Cell Proliferation ◽  
Growth Factors ◽  
Chick Embryo ◽  
Calf Serum ◽  
Cell Number ◽  
Otic Vesicle ◽  
Thymidine Uptake ◽  
Normal Pattern ◽  
Proliferative Growth ◽  
Otic Vesicles

The ability of the mitogenic peptide bombesin and other growth factors to trigger and support early development of the inner ear was studied on chick embryo otocysts in culture. The normal pattern of development was preserved in cultured otic vesicles in the presence of 20% fetal calf serum in the medium. Differentiation proceeded from stage 18 to 22 during the first 24 h and further to stage 24 in 48 h. Estimates of cell number and mitotic rates revealed a distinct period of proliferative growth which was maximum at the 24 h period of incubation. This was coincident with a high rate of DNA synthesis as measured by the acid-precipitable incorporation of [3H]thymidine. Development could be arrested by deprivation of serum during 24h. It could then be reactivated by readmission of serum to proceed with the normal pattern of morphological differentiation and cell proliferation. Bombesin (100 nM) was able to reactivate development in growth-arrested vesicles. Its effect was dose-dependent, saturable and potentiated by insulin (5 micrograms ml-1) which was ineffective if used alone. When associated with insulin, bombesin carried differentiation to stage 21 and stimulated mitotic activity above the level of serum as judged from estimates of cell number and [3H]thymidine uptake. EGF and PDGF were also effective in reinitiating development although their potency was smaller than bombesin. The reactivation by serum or bombesin was blocked by amiloride. The results show that (1) the otic vesicle can provide a useful model for studying the mechanisms that control proliferative growth and differentiation during normal development and (2) bombesin and other growth factors are able to activate growth in embryonic developing tissues.

scholarly journals EFFECTS OF CYCLIC AMP AND SEPHADEX FRACTIONS OF CHICK EMBRYO EXTRACT ON CLONED RETINAL PIGMENTED EPITHELIUM IN TISSUE CULTURE

1974 ◽  
Vol 61 (2) ◽  
pp. 369-382 ◽  
Author(s):  
D. A. Newsome ◽  
R. T. Fletcher ◽  
W. G. Robison ◽  
K. R. Kenyon ◽  
G. J. Chader
Keyword(s):  
Molecular Weight ◽  
Chick Embryo ◽  
Adenosine Monophosphate ◽  
Cell Number ◽  
Retinal Pigmented Epithelium ◽  
Culture Dish ◽  
Adhesive Properties ◽  
Embryo Extract ◽  
Chick Embryo Extract ◽  
Pigmented Epithelium

The effects of dibutyryl cyclic 3',5'-adenosine monophosphate (BcAMP) and Sephadex G-25 fractions of chick embryo extract on the growth rate, morphology, and pigmentation of normal chick retinal pigmented epithelium (PE) were investigated. Seven cloned PE cell lines were each grown in modified Ham's F-12 medium alone (F-12), or in F-12 supplemented with either high molecular weight (H) or low molecular weight (L) fractions of chick embryo extract. Cells grown in F-12 alone or in L medium formed compact epithelial sheets, whereas cells grown in H had a fibrocytic appearance and formed poorly organized monolayers. In H plus BcAMP, cell morphology was more epithelioid than in H alone, and generally the monolayers appeared more differentiated. Under each of these three culture conditions, 2 x 10-4 M BCAMP retarded the increase in cell number and decreased the final number of cells per culture dish, but had little effect on plating efficiency. BcAMP also increased the rate of cell adhesion to a plastic substratum. Pigmentation was marked in cultures grown in F-12 or in L alone, but the addition of BcAMP dramatically reduced visible pigmentation. This effect was reversed when BcAMP was removed from the culture medium. Thus BcAMP modifies cell and colonial morphology, rate of cell accumulation, adhesive properties, and pigmentation of normal PE cells.

scholarly journals Müllerian Inhibiting Substance Is Required for Germ Cell Proliferation during Early Gonadal Differentiation in Medaka (Oryzias latipes)

Endocrinology ◽  
2007 ◽  
Vol 149 (4) ◽  
pp. 1813-1819 ◽  
Author(s):  
Eri Shiraishi ◽  
Norifumi Yoshinaga ◽  
Takeshi Miura ◽  
Hayato Yokoi ◽  
Yuko Wakamatsu ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
Germ Cell ◽  
Germ Cells ◽  
Sex Differentiation ◽  
Somatic Cells ◽  
Oryzias Latipes ◽  
Cell Number ◽  
Gonadal Differentiation ◽  
Loss Of Function ◽  
Germ Cell Proliferation

Müllerian inhibiting substance (MIS) is a glycoprotein belonging to the TGF-β superfamily. In mammals, MIS is responsible for the regression of Müllerian ducts in the male fetus. However, the role of MIS in gonadal sex differentiation of teleost fish, which have no Müllerian ducts, has yet to be clarified. In the present study, we examined the expression pattern of mis and mis type 2 receptor (misr2) mRNAs and the function of MIS signaling in early gonadal differentiation in medaka (teleost, Oryzias latipes). In situ hybridization showed that both mis and misr2 mRNAs were expressed in the somatic cells surrounding the germ cells of both sexes during early sex differentiation. Loss-of-function of either MIS or MIS type II receptor (MISRII) in medaka resulted in suppression of germ cell proliferation during sex differentiation. These results were supported by cell proliferation assay using 5-bromo-2′-deoxyuridine labeling analysis. Treatment of tissue fragments containing germ cells with recombinant eel MIS significantly induced germ cell proliferation in both sexes compared with the untreated control. On the other hand, culture of tissue fragments from the MIS- or MISRII-defective embryos inhibited proliferation of germ cells in both sexes. Moreover, treatment with recombinant eel MIS in the MIS-defective embryos dose-dependently increased germ cell number in both sexes, whereas in the MISRII-defective embryos, it did not permit proliferation of germ cells. These results suggest that in medaka, MIS indirectly stimulates germ cell proliferation through MISRII, expressed in the somatic cells immediately after they reach the gonadal primordium.

Rapid Growth of Radish Sprouts Using Low Pressure O2Radio Frequency Plasma Irradiation

2012 ◽  
Vol 1469 ◽  
Author(s):  
Satoshi Kitazaki ◽  
Kazunori Koga ◽  
Masaharu Shiratani ◽  
Nobuya Hayashi
Keyword(s):  
Cell Proliferation ◽  
Cell Morphology ◽  
Rapid Growth ◽  
Average Length ◽  
Growth Enhancement ◽  
Radio Frequency Plasma ◽  
Plasma Irradiation ◽  
Frequency Plasma ◽  
Irradiation Cell ◽  
Radish Sprouts

ABSTRACTWe compared growth enhancement of radish induced by O2, air, and Ar plasma irradiation. The average length of radish sprouts cultivated for 4 days after O2plasma irradiation is 70% longer than that of sprouts without irradiation. The O2plasma irradiation is more effective in enhancing growth than air and Ar radio frequency plasma irradiation. Cell morphology and cell size of sprouts with O2plasma irradiation is nearly the same as those without irradiation. These results suggest that plasma induced acceleration of cell proliferation brings about the rapid growth.

Cell proliferation in the gastrulating chick embryo: a study using BrdU incorporation and PCNA localization

Development ◽  
1993 ◽  
Vol 118 (2) ◽  
pp. 389-399 ◽  
Author(s):  
E.J. Sanders ◽  
M. Varedi ◽  
A.S. French
Keyword(s):  
Cell Proliferation ◽  
Chick Embryo ◽  
Cell Density ◽  
Generation Time ◽  
Primitive Streak ◽  
S Phase ◽  
Nuclear Antigen ◽  
Brdu Incorporation ◽  
Similar Proportion ◽  
Differential Growth

Cell proliferation in the gastrulating chick embryo was assessed using two independent techniques which mark cells in S phase of the mitotic cycle: nuclear incorporation of bromodeoxyuridine (BrdU) detected immunocytochemically and immunolocalization of proliferating cell nuclear antigen (PCNA). Computer-reconstructed maps were produced showing the distribution of labelled nuclei in the primitive streak and the cell layers. These distributions were also normalized to take into account regional differences in cell density across the embryo. Results from a 2 hour pulse of BrdU indicated that although cells at caudal levels of the primitive streak showed the highest incorporation, this region showed a similar proportion of labelled cells to the surrounding caudal regions of the epiblast and mesoderm when normalized for cell density. The entire caudal third of the embryo showed the highest proportion of cells in S phase. Cells of Hensen's node showed a relatively low rate of incorporation and, although the chordamesoderm cells showed many labelled nuclei, this appeared to be a reflection of a high cell density in this region. Combining this result with results from a 4 hour pulse of BrdU permitted mapping of cell generation time across the entire embryo. Generation times ranged from a low value of approximately 2 hours at caudal levels of both the epiblast and mesoderm, to an upper value of approximately 10 hours in the rostral regions of the primitive streak, in the mid-lateral levels of the epiblast and in the chordamesoderm rostral to Hensen's node. Cells at caudal regions of the primitive streak showed a generation time of approximately 5 hours. Taking into account that cells are generally considered to be continuously moving through the primitive streak, we conclude that cell division, as judged by generation time, is greatly reduced during transit through this region, despite the presence there of cells in S phase and M phase. Immunocytochemical localization of PCNA-positive nuclei gave generally similar distributions to those obtained with BrdU incorporation, confirming that this endogenous molecule is a useful S-phase marker during early embryogenesis. Mid-levels and caudal levels of the primitive streak showed the highest numbers of positive nuclei, and the highest proportion of labelling after cell density was accounted for. As with BrdU incorporation, the highest proportions of PCNA-positive nuclei were found towards the caudal regions of the epiblast and mesoderm. These results suggest that the differential growth of the caudal region of the embryo at this time is a direct consequence of elevated levels of cell proliferation in this region.(ABSTRACT TRUNCATED AT 400 WORDS)

scholarly journals Lithium carbonate sedimentation using flocculants with different ionic bases

2021 ◽  
pp. 20-20
Author(s):  
Yam Morales ◽  
Nelson Herrera ◽  
Kevin Pérez
Keyword(s):  
Sedimentation Rate ◽  
Rapid Growth ◽  
Crystallization Process ◽  
Lithium Carbonate ◽  
Rechargeable Batteries ◽  
Point Of View ◽  
Sedimentation Rates ◽  
Economic Point ◽  
Carbonate Sedimentation ◽  
Cationic Flocculant

Lithium has become a metal of enormous interest worldwide. The extensive use of rechargeable batteries for a range of applications has pushed for rapid growth in demand for lithium carbonate. This compound is produced by crystallization, by reaction with lithium chloride (in solution) and by adding sodium carbonate. Low sedimentation rates in the evaporation pools present a problem in the crystallization process. For this reason, in this work, mineral sedimentation tests were carried out with the use of two flocculant types with different ionic charges. The tests were carried out at a laboratory level using different dosages for each flocculant and measurements were performed to obtain the increase in the content of solids in the sediment. The anionic flocculant had better performance as compared to that of the cationic flocculant, increasing the sedimentation rate of lithium carbonate by up to 6.5. However, similar solids contents were obtained with the use of the cationic flocculant at 3.5 times lower dosage making it the flocculant of choice regarding the economic point of view.

Improving Biomaterials from a Cellular Point of View

2006 ◽  
Vol 925 ◽  
Author(s):  
Venu Gopal Varanasi ◽  
T. Vallortigara ◽  
P. M. Loomer ◽  
E. Saiz ◽  
A. P. Tomsia ◽  
...  
Keyword(s):  
Dissolution Rate ◽  
Cell Number ◽  
Point Of View ◽  
Dissolution Behavior ◽  
Ti Alloy ◽  
Bioactive Glasses ◽  
Culture Studies ◽  
Cell Numbers ◽  
Number Increase

ABSTRACTBioactive glasses (6P55) used for coating Ti/Ti-alloy were tested for their in vitro behavior in a comparative study with commercial Bioglass™ (45S5) and commercial Ti alloy (Ti6Al4V). In vitro testing included pH and dissolution rate determination in simulated body fluid (SBF) along with in vitro cyto compatibility testing. It was seen in this work that 6P55 and 45S5 had similar dissolution behavior, demonstrating t½ dependence and maximum pH of approximately 8.1 after 10 days of immersion. This pH was reduce by 0.2 0.4 pH units when the in vitro V:A ratio was increased from 1 to 3. The dissolution rate of these glasses approached 0 after additional immersion tests after 15 days and the pH stablilized at less than 7.5. Cell culture studies showed that both glasses behaved in similar fashion after 16 hours in culture. Both glasses had an increase in cell numbers of close to 200-250%, whereas Ti6Al4V had a less pronounced cell number increase (∼ 180%)

The relationship between cell proliferation and the transcription of the nuclear oncogenes c-myc, c-myb and c-ets-1 during feather morphogenesis in the chick embryo

Development ◽  
1991 ◽  
Vol 111 (3) ◽  
pp. 699-713 ◽  
Author(s):  
X. Desbiens ◽  
C. Queva ◽  
T. Jaffredo ◽  
D. Stehelin ◽  
B. Vandenbunder
Keyword(s):  
Cell Proliferation ◽  
Endothelial Cells ◽  
Spatial Distribution ◽  
Chick Embryo ◽  
Expression Patterns ◽  
S Phase ◽  
Skin Morphogenesis ◽  
Dermal Cells ◽  
The Relationship

We have described the expression of three nuclear protooncogenes, c-myc, c-myb and c-ets-1 during feather morphogenesis in the chick embryo. In parallel with the expression patterns obtained by in situ hybridization, we have mapped the spatial distribution of S-phase cells by monitoring the incorporation of 5-bromodeoxyuridine. We do not detect c-myc or c-myb transcripts during the early stages when S-phase cells are scattered in the dermis and in the epidermis. Rather c-ets-1 transcripts are abundant in the dermal cells which divide and accumulate under the uniform epidermis. At the onset of the formation of the feather bud, cells within each rudiment cease DNA replicative activities and c-myc transcripts are detected both in the epidermis and in the underlying dermis. This expression precedes the reentry into the S phase. The transcription of c-myb, which has been previously tightly linked to hemopoietic cells is also detected in the developing skin. This expression is essentially located in proliferating epidermal cells on and after the beginning of feather outgrowth. As feather outgrowth proceeds, the distribution of c-myc and c-myb transcripts is restricted to the highly proliferating epidermis. In contrast c-ets-1 transcripts are never detected in the epidermis. During the later stages of skin morphogenesis, the transcription of c-ets-1 is restricted to the endothelial cells of blood vessels, as previously described. We suggest that the differential expression of these nuclear oncogenes reflects the activation of different mitotic controlling pathways during the development of the skin.

The appearance and quantitation of cytoplasmic ribonucleic acid in the early chick embryo

Development ◽  
1972 ◽  
Vol 28 (2) ◽  
pp. 367-384
Author(s):  
C. C. Wylie
Keyword(s):  
Chick Embryo ◽  
Ribosomal Rna ◽  
Rna Synthesis ◽  
Specific Activity ◽  
Cell Number ◽  
Present Knowledge ◽  
Precursor Pool ◽  
Cytoplasmic Rna ◽  
Labelling Experiment ◽  
Neurula Stage

This paper seeks to extend our knowledge about RNA synthesis in early embryogenesis to the domestic fowl, Gallus domesticus. Using this species for research, apart from increasing our knowledge of higher vertebrate embryology, has certain advantages such as rapid uptake of isotopic precursors and ease of microdissection in culture. The following results are presented: (1) The cell number in the whole chick embryos is shown to be increasing logarithmically between the time of laying and the early neurula stage; with a doubling time of 7·4 h. (2) The onset of ribosomal RNA synthesis has been shown to be during mid-cleavage of the chick embryo, while development is taking place in the oviduct and uterus of the mother. (3) In a cumulative labelling experiment, embryos were labelled at the unincubated-egg stage, allowed to develop to various morphological stages up to neurulation, and their cytoplasmic RNA prepared and analysed by gel electrophoresis. (4) The specific activity of the precursor pool for RNA synthesis was measured at several stages, using the same labelling conditions, and the results were used to quantitate the RNA synthesis from the incorporated radioactivity. (5) Using these techniques, it was found that newly synthesized cytoplasmic RNA accumulates steadily in the whole chick embryo, reaching a level of 104 μg by the early neurula stage. On a per cell basis, however, the amount of newly synthesized cytoplasmic RNA seems to decrease slightly. These findings are discussed in the light of present knowledge about embryos of other vertebrates and certain invertebrates.

Micromere fate maps in leech embryos: lineage-specific differences in rates of cell proliferation

Development ◽  
1994 ◽  
Vol 120 (12) ◽  
pp. 3427-3438 ◽  
Author(s):  
C. M. Smith ◽  
D. A. Weisblat
Keyword(s):  
Cell Proliferation ◽  
Late Stage ◽  
Squamous Epithelium ◽  
Cell Lineage ◽  
Cell Number ◽  
Animal Pole ◽  
Fluorescent Cell ◽  
Plate Formation

Stereotyped early cleavages in glossiphoniid leech embryos yield 25 micromeres, along with 3 macromeres and 10 teloblasts. The micromeres generate prostomial tissues and also give rise to most of the squamous epithelium of a provisional integument that spreads epibolically from the animal pole, covering the rest of the embryo during germinal plate formation. We systematically injected individual micromeres with fluorescent cell lineage tracers at the time of their birth and quantitatively mapped the contributions of all these cells to the late stage 7 embryo, a time in development that is early in the epibolic expansion. At this time, micromere derivatives comprise two types of cells: squamous epithelial (superficial) cells that cover the germinal bands and the region of the animal cap between the germinal bands; and underlying (deep) cells that are confined to the distal ends of the germinal bands and in the area between their distal ends. We find that individual micromeres contribute clones of deep and/or superficial progeny that are stereotyped with respect to both numbers and types of cells in the clone and the domains that they occupy. The N teloblasts also contribute cells to the squamous epithelium. We find significant differences in the rate of cell proliferation between different micromere clones. These differences appear to reflect lineage-specific traits, since there is little or no regulation of cell number after ablation of individual micromeres.

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