Nucleic acid and protein synthesis and pattern regulation in hydra

Development ◽  
1969 ◽  
Vol 21 (1) ◽  
pp. 55-70
Author(s):  
S. G. Clarkson
Keyword(s):  
Protein Synthesis ◽  
Dna Synthesis ◽  
Experimental Approach ◽  
Direct Evidence ◽  
Animal Cells ◽  
Rna And Protein Synthesis ◽  
Metabolic Activities ◽  
Time Required ◽  
Pattern Regulation

In a previous paper (Clarkson, 1969) data were presented which indicate that hypostome determination is accompanied by a large and rapid burst of RNA synthesis, a slight stimulation of protein synthesis, and no increase in DNA synthesis. More direct evidence concerning the relative importance of these metabolic activities in hypostome determination is reported in this paper. The experimental approach made use of the transplantation test of Webster & Wolpert (1966) in conjunction with some inhibitors of DNA, RNA and protein synthesis, the rationale being that if these metabolic activities play important roles in the determination of the hypostome, then their inhibition would be expected to have severe effects on the time required for this process. Regarding the inhibitors, hydroxyurea (HU) inhibits DNA synthesis in a variety of animal cells without altering rates of formation of RNA or protein (Young & Hodas, 1964; Yarbro, Kennedy & Barnum, 1965; Schwartz, Garofalo, Sternberg & Philips, 1965).

scholarly journals Comparison of Cellular and Biomass Specific Activities of Dominant Bacterioplankton Groups in Stratified Waters of the Celtic Sea

2001 ◽  
Vol 67 (11) ◽  
pp. 5210-5218 ◽  
Author(s):  
Mikhail V. Zubkov ◽  
Bernhard M. Fuchs ◽  
Peter H. Burkill ◽  
Rudolf Amann
Keyword(s):  
Protein Synthesis ◽  
Cellular Protein ◽  
Light Scatter ◽  
Flow Sorting ◽  
Sorting Technique ◽  
Specific Activities ◽  
Celtic Sea ◽  
Metabolic Activities

ABSTRACT A flow-sorting technique was developed to determine unperturbed metabolic activities of phylogenetically characterized bacterioplankton groups with incorporation rates of [35S]methionine tracer. According to fluorescence in situ hybridization with rRNA targeted oligonucleotide probes, a clade of α-proteobacteria, related to Roseobacter spp., and aCytophaga-Flavobacterium cluster dominated the different groups. Cytometric characterization revealed both these groups to have high DNA (HNA) content, while the α-proteobacteria exhibited high light scatter (hs) and the Cytophaga-Flavobacteriumcluster exhibited low light scatter (ls). A third abundant group with low DNA (LNA) content contained cells from a SAR86 cluster of γ-proteobacteria. Cellular specific activities of the HNA-hs group were 4- and 1.7-fold higher than the activities in the HNA-ls and LNA groups, respectively. However, the higher cellular protein synthesis by the HNA-hs could simply be explained by their maintenance of a larger cellular protein biomass. Similar biomass specific activities of the different groups strongly support the main assumption that underlies the determination of bacterial production: different bacteria in a complex community incorporate amino acids at a rate proportional to their protein synthesis. The fact that the highest growth-specific rates were determined for the smallest cells of the LNA group can explain the dominance of this group in nutrient-limited waters. The metabolic activities of the three groups accounted for almost the total bacterioplankton activity, indicating their key biogeochemical role in the planktonic ecosystem of the Celtic Sea.

scholarly journals Positional information and pattern regulation in hydra: formation of the foot end

Development ◽  
1973 ◽  
Vol 30 (3) ◽  
pp. 727-740
Author(s):  
J. Hicklin ◽  
L. Wolpert
Keyword(s):  
Positional Information ◽  
Basal Disc ◽  
Time Required ◽  
Pattern Regulation

The time required for foot end formation increases with distance from the foot end. Using lateral grafting it was shown that both the peduncle and basal disc could induce a proximal axis when grafted into the gastric region. The time for foot end determination was shown to be about 4 h at the proximal end of the gastric region and to increase towards the head end. In general the determination of the foot end is similar to that of the head end.

scholarly journals Protein, nucleic acid and starch metabolism in the duckweed Spirodela oligorrhiza, treated with cytokinins

1972 ◽  
Vol 129 (2) ◽  
pp. 403-417 ◽  
Author(s):  
P. J. A. McCombs ◽  
R. K. Ralph
Keyword(s):  
Protein Synthesis ◽  
Specific Protein ◽  
Starch Metabolism ◽  
Animal Cells ◽  
Stringent Control ◽  
Inhibition Of Growth ◽  
Rna And Protein Synthesis ◽  
Membrane Bound ◽  
Spirodela Oligorrhiza ◽  
Protein Nucleic Acid

Bacteria-free cultures of Spirodela oligorrhiza continue to increase in frond number for 2 to 3 days after transfer to darkness. There is then no further increase in frond number for 3 to 4 weeks, although DNA, RNA and protein synthesis continue at decreased rates and starch accumulates in the plants. We refer to such ‘non-growing’ plants in darkness as dormant. Adding kinetin to dormant Spirodela initiated increased DNA, RNA and protein synthesis within 1h, although new fronds were not detected until 24h after the addition of kinetin. The frond number then continued to increase. Starch accumulated in dormant plants. Accumulation of starch appeared to be a consequence of inhibition of growth rather than the converse. No evidence was obtained for a block in [14C]glucose metabolism that might explain the lack of growth in darkness in the absence of kinetin. In darkness, more ribosomes were membrane-bound in dormant Spirodela than in Spirodela growing with kinetin. Similarities between the response of Spirodela to darkness, stringent control in bacteria and pleiotypic controls in animal cells are discussed. It is suggested that all three processes are ultimately controlled by specific protein kinases that are individually sensitive to different effectors.

scholarly journals MACROMOLECULAR SYNTHESES RELATED TO THE REPRODUCTIVE CYST OF TETRAHYMENA PATULA

1973 ◽  
Vol 59 (3) ◽  
pp. 615-623 ◽  
Author(s):  
P. R. Gabe ◽  
L. E. de Bault
Keyword(s):  
Protein Synthesis ◽  
Dna Synthesis ◽  
Generation Time ◽  
Rna Synthesis ◽  
Culture Medium ◽  
Tritiated Thymidine ◽  
Growth Cycle ◽  
The Third ◽  
Rna And Protein Synthesis ◽  
The Mean

Macromolecular syntheses in encysted Tetrahymena patula were studied using Feulgen fluorescence cytophotometry, autoradiography, and inhibitors of RNA and protein synthesis. Cycloheximide significantly depressed protein synthesis and D-actinomycin effectively blocked RNA synthesis. Under these conditions, the cells within the cyst were unable to divide. Both cytophotometric measurements and autoradiographic data with tritiated thymidine show that DNA synthesis does not occur during the encystment divisions. Excysted cells placed in nutrient broth medium showed a prolonged generation time after the first cell growth cycle, and by the third generation the mean DNA content per cell was almost triple that of starved excysted cells. These findings indicate that (a) the encystment divisions require RNA and protein synthesis, which are apparently effected through turnover, (b) the encystment division cycles occur in the absence of DNA synthesis, and (c) excysted cells placed in culture medium may go through more than one DNA replication per cell cycle.

Inhibition of protein synthesis by zinc: comparison between protein synthesis and RNA synthesis

1998 ◽  
Vol 17 (12) ◽  
pp. 661-667 ◽  
Author(s):  
Udo Ingbert Walther ◽  
Johannes Schulze ◽  
Wolfgang Forth
Keyword(s):  
Protein Synthesis ◽  
Rna Synthesis ◽  
A549 Cells ◽  
Zinc Toxicity ◽  
Alveolar Type ◽  
Time Curve ◽  
Synthesis Inhibition ◽  
Protein And Rna Synthesis ◽  
Rna And Protein Synthesis

Inhalation of zinc fumes may lead to the acute respiratory distress syndrome. The mechanisms of pulmonary zinc toxicity are not yet understood. Therefore we investigated zinc-dependent depression of protein and RNA synthesis in rat and human lung cell lines. 1 After exposure to 120 or 150 mmol/l zinc, RNA synthesis as assessed by uridine incorporation decreased by 60-70% between 0 and 2 h exposition in rat alveolar type II cells (L2 cells) and human fibroblast-like cells (11Lu and 16Lu cells), and by 90% between 0 and 4 h in carcinoma-derived cells (A549 cells). 2 After 2 h exposure, L2, 11Lu, and 16Lu cells were half-maximally inhibited by 50 mmol/l zinc, whereas A549 cells were more resistant with half-maximal inhibition at 100 mmol/zinc. 3 Protein and RNA synthesis was inhibited in parallel in L2, 11Lu, and A549 cells as indicated by simultaneous determination of uridine and amino acid incorporation. In 16Lu cells, the decline in protein synthesis preceded RNA synthesis inhibition. Pretreatment with RNA synthesis inhibitors (amanitin or actinomycin D) had no effect on time curve and intensity of RNA synthesis inhibition. Taken together, our results indicate that the suppression of RNA and protein synthesis likely are independent phenomena, due to direct zinc effects on these biosynthetic pathways.

scholarly journals Relationship of Critical Temperature to Macromolecular Synthesis and Growth Yield in Psychrobacter cryopegella

2004 ◽  
Vol 186 (8) ◽  
pp. 2340-2345 ◽  
Author(s):  
Corien Bakermans ◽  
Kenneth H. Nealson
Keyword(s):  
Growth Rate ◽  
Protein Synthesis ◽  
Critical Temperature ◽  
Low Temperature ◽  
Dna Synthesis ◽  
Temperature Dependence ◽  
Low Temperatures ◽  
Growth Yield ◽  
Synthesis Rate ◽  
Rna And Protein Synthesis

ABSTRACT Most microorganisms isolated from low-temperature environments (below 4°C) are eury-, not steno-, psychrophiles. While psychrophiles maximize or maintain growth yield at low temperatures to compensate for low growth rate, the mechanisms involved remain unknown, as does the strategy used by eurypsychrophiles to survive wide ranges of temperatures that include subzero temperatures. Our studies involve the eurypsychrophilic bacterium Psychrobacter cryopegella, which was isolated from a briny water lens within Siberian permafrost, where the temperature is −12°C. P. cryopegella is capable of reproducing from −10 to 28°C, with its maximum growth rate at 22°C. We examined the temperature dependence of growth rate, growth yield, and macromolecular (DNA, RNA, and protein) synthesis rates for P. cryopegella. Below 22°C, the growth of P. cryopegella was separated into two domains at the critical temperature (T critical = 4°C). RNA, protein, and DNA synthesis rates decreased exponentially with decreasing temperatures. Only the temperature dependence of the DNA synthesis rate changed at T critical. When normalized to growth rate, RNA and protein synthesis reached a minimum at T critical, while DNA synthesis remained constant over the entire temperature range. Growth yield peaked at about T critical and declined rapidly as temperature decreased further. Similar to some stenopsychrophiles, P. cryopegella maximized growth yield at low temperatures and did so by streamlining growth processes at T critical. Identifying the specific processes which result in T critical will be vital to understanding both low-temperature growth and growth over a wide range of temperatures.

scholarly journals Inhibitor effects during the cell cycle in Chlamydomonas reinhardtii. Determination of transition points in asynchronous cultures.

1975 ◽  
Vol 67 (1) ◽  
pp. 126-135 ◽  
Author(s):  
S H Howell ◽  
W J Blaschko ◽  
C M Drew
Keyword(s):  
Cell Cycle ◽  
Protein Synthesis ◽  
Cell Division ◽  
Chlamydomonas Reinhardtii ◽  
Macromolecular Synthesis ◽  
Synchronous Cultures ◽  
Organellar Dna ◽  
Rna And Protein Synthesis ◽  
Transition Points

A wide variety of inhibitors (drugs, antibiotics, and antimetabolites) will block cell division within an ongoing cell cycle in autotrophic cultures of Chlamydomonas reinhardtii. To determine when during the cell cycle a given inhibitor is effective in preventing cell division, a technique is described which does not rely on the use of synchronous cultures. The technique permits the measurement of transition points, the cell cycle stage at which the subsequent cell division becomes insensitive to the effects of an inhibitor. A map of transition points in the cell cycle reveals that they are grouped into two broad periods, the second and fourth quarters. In general, inhibitors which block organellar DNA, RNA, and protein synthesis have second-quarter transition points, while those which inhibit nuclear cytoplasmic macromolecular synthesis have fourth-quarter transition points. The specific grouping of these transition points into two periods suggests that the synthesis of organellar components is completed midway through the cell cycle and that the synthesis of nonorganellar components required for cell division is not completed until late in the cell cycle.

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