scholarly journals Growth-related fluctuation in messenger RNA utilization in animal cells.

1978 ◽  
Vol 79 (1) ◽  
pp. 85-86 ◽  
Author(s):  
G T Lee ◽  
D L Engelhardt
Keyword(s):  
Stationary Phase ◽  
Messenger Rna ◽  
Protein Biosynthesis ◽  
Growth Cycle ◽  
Exponential Phase ◽  
Wheat Germ Extract ◽  
Animal Cells ◽  
Translational Initiation ◽  
Large Size ◽  
Polyadenylated Rna

Monkey fibroblasts maintained in culture regulate their levels of intracellular protein throughout the growth cycle by means of variations in the rate of protein biosynthesis. Cytoplasmic mRNA in stationary phase cells was compared to that in exponential phase cells. In stationary phase cells 56% of the cytoplasmic polyadenylated RNA was found in the 40--90S postpolysomal region of sucrose sedimentation gradients, while only 23% was found in this region in exponential phase cells. Analysis of electron micrographs of sectioned exponential and stationary phase cells revealed that this shift in polyadenylated RNA location is accompanied by a loss of polysome-like aggregates of ribosomes. Most if not all of this species of postpolysomal polyadenylated RNA is not being translated by single ribosomes since no detectable amounts of nascent peptide were present in this region. This nonpolysomal polyadenylated RNA is comparable in size to polysomal polyadenylated RNA. The length of the 3'-poly(A) tract was also comparable for these two species. The extent of capping of poly(A)-containing molecules was also comparable for these two species. The template activity of nonpolysomal RNA in a wheat germ extract was comparable to that of polysomal RNA. The peptides produced by these two preparations were of a similar large size. Furthermore, most of the nonpolysomal polyadenylated RNA of stationary phase cells was driven into polysomes in the presence of a low dose of cycloheximide. Therefore, we conclude that the untranslated mRNA that accumulates in stationary phase cells is structurally intact, is fully capable of being translated, and is not being translated due to the operation of a translational initiation block.

scholarly journals The mannophosphoinositides of Corynebacterium aquaticum

1975 ◽  
Vol 148 (2) ◽  
pp. 253-258 ◽  
Author(s):  
J A Hackett ◽  
P J Brennan
Keyword(s):  
Stationary Phase ◽  
Exponential Growth ◽  
Growth Cycle ◽  
Exponential Phase ◽  
Late Stationary Phase ◽  
Late Exponential Phase

Besides the monomannophosphoinositide previously reported in Corynebacterium aquaticum small amounts of other, apparently more glycosylated, mannophosphoinositides have been identified in stationary phase cells. Moreover, by labelling cells with [32P]Pi, phosphatidylinositol was found, comprising about 1.5% of the stationary-phase phospholipids. 2. Pulse-chase experiments performed on cells in the late exponential phase of growth further suggested the sequence phosphatidylinositol leads to monomannophosphoinositide as the first step in the biosynthesis of the mannophosphoinositides. 3. Di-and tri-mannophosphoinositides are apparently the main mannophosphoinositides present during exponential growth. Monomannophosphoinositide predominates only in late stationary phase; in the earlier stationary phase, phosphatidylinositol comprises 50% of the phosphoinositide lipid, and tetramannophosphoinositide constitutes much of the remainder. 4. The metabolism and functions of the mannophosphoinositides are discussed, particularly in relation to changes in their composition throughout the growth cycle.

scholarly journals OseIF3h Regulates Plant Growth and Pollen Development at Translational Level Presumably through Interaction with OsMTA2

Plants ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 1101
Author(s):  
Yuqing Huang ◽  
Peng Zheng ◽  
Xuejiao Liu ◽  
Hao Chen ◽  
Jumin Tu
Keyword(s):  
Plant Growth ◽  
Translation Initiation ◽  
Pollen Development ◽  
Messenger Rna ◽  
Protein Biosynthesis ◽  
Translation Initiation Factor ◽  
Initiation Factor ◽  
Sequencing Data ◽  
Knock Out ◽  
Translational Level

The initiation stage of protein biosynthesis is a sophisticated process tightly regulated by numerous initiation factors and their associated components. However, the mechanism underlying translation initiation has not been completely understood in rice. Here, we showed knock-out mutation of the rice eukaryotic translation initiation factor 3 subunit h (OseIF3h) resulted in plant growth retardation and seed-setting rate reduction as compared to the wild type. Further investigation demonstrated an interaction between OseIF3h and OsMTA2 (mRNA adenosine methylase 2), a rice homolog of METTL3 (methyltransferase-like 3) in mammals, which provided new insight into how N6-methyladenosine (m6A) modification of messenger RNA (mRNA) is engaged in the translation initiation process in monocot species. Moreover, the RIP-seq (RNA immunoprecipitation sequencing) data suggested that OseIF3h was involved in multiple biological processes, including photosynthesis, cellular metabolic process, precursor metabolites, and energy generation. Therefore, we infer that OseIF3h interacts with OsMTA2 to target a particular subset of genes at translational level, regulating plant growth and pollen development.

scholarly journals Metabolic, Physiological, and Transcriptomics Analysis of Batch Cultures of the Green Microalga Chlamydomonas Grown on Different Acetate Concentrations

Cells ◽  
2019 ◽  
Vol 8 (11) ◽  
pp. 1367 ◽  
Author(s):  
Bogaert ◽  
Perez ◽  
Rumin ◽  
Giltay ◽  
Carone ◽  
...  
Keyword(s):  
Stationary Phase ◽  
Biomass Yield ◽  
Fatty Acid Content ◽  
Biological Significance ◽  
Exponential Phase ◽  
Low Light ◽  
Batch Mode ◽  
Batch Cultures ◽  
Green Microalga ◽  
Transcriptomics Data

Acetate can be efficiently metabolized by the green microalga Chlamydomonas reinhardtii. The regular concentration is 17 mM, although higher concentrations are reported to increase starch and fatty acid content. To understand the responses to higher acetate concentrations, Chlamydomonas cells were cultivated in batch mode in the light at 17, 31, 44, and 57 mM acetate. Metabolic analyses show that cells grown at 57 mM acetate possess increased contents of all components analyzed (starch, chlorophylls, fatty acids, and proteins), with a three-fold increased volumetric biomass yield compared to cells cultivated at 17 mM acetate at the entry of stationary phase. Physiological analyses highlight the importance of photosynthesis for the low-acetate and exponential-phase samples. The stationary phase is reached when acetate is depleted, except for the cells grown at 57 mM acetate, which still divide until ammonium exhaustion. Surprisal analysis of the transcriptomics data supports the biological significance of our experiments. This allows the establishment of a model for acetate assimilation, its transcriptional regulation and the identification of candidates for genetic engineering of this metabolic pathway. Altogether, our analyses suggest that growing at high-acetate concentrations could increase biomass productivities in low-light and CO2-limiting air-bubbled medium for biotechnology.

scholarly journals Survival of virulentLegionella pneumophilain aerosols

1983 ◽  
Vol 90 (3) ◽  
pp. 451-460 ◽  
Author(s):  
P. Hambleton ◽  
M. G. Broster ◽  
P. J. Dennis ◽  
R. Henstridge ◽  
R. Fitzgeorge ◽  
...  
Keyword(s):  
Stationary Phase ◽  
Respiratory Disease ◽  
Legionella Pneumophila ◽  
Solid Medium ◽  
Exponential Phase ◽  
Metabolic Status ◽  
Aqueous Suspensions

SUMMARYAqueous suspensions of virulentLegionellapneumophilagrown on solid medium retained virulence and aerosol survival characteristics for several months. Significant numbers of viable organisms were recovered from aerosols held at various relative humidities (r.h.) for up to 2 h. The organisms survived best at 65% r.h. and were least stable at 55% r.h.Exponential phase broth-grown organisms survived poorly in aerosols in comparison with stationary phase broth cultures or organisms grown on solid medium, suggesting that the metabolic status ofLegionella pneumophilaorganisms may be an important factor affecting their ability to survive in aerosols and cause respiratory disease.

Mannose-Binding Activity of Escherichia coli: a Determinant of Attachment and Ingestion of the Bacteria by Macrophages

1980 ◽  
Vol 29 (2) ◽  
pp. 417-424
Author(s):  
Zvi Bar-Shavit ◽  
Rachel Goldman ◽  
Itzhak Ofek ◽  
Nathan Sharon ◽  
David Mirelman
Keyword(s):  
Escherichia Coli ◽  
Stationary Phase ◽  
Pathogenic Bacteria ◽  
Binding Activity ◽  
Exponential Phase ◽  
Restrictive Temperature ◽  
Filamentous Bacteria ◽  
Phagocytic Cells ◽  
E Coli ◽  
Mannose Binding

Recently, it was suggested that a mannose-specific lectin on the bacterial cell surface is responsible for the recognition by phagocytic cells of certain nonopsonized Escherichia coli strains. In this study we assessed the interaction of two strains of E. coli at different phases of growth with a monolayer of mouse peritoneal macrophages and developed a direct method with [ 14 C]mannan to quantitate the bacterial mannose-binding activity. Normal-sized bacteria were obtained from logarithmic and stationary phases of growth. Nonseptated filamentous cells were formed by growing the organisms in the presence of cephalexin or at a restrictive temperature. Attachment to macrophages of all bacterial forms was inhibited by methyl α- d -mannoside and mannan but not by other sugars tested. The attachment of stationary phase and filamentous bacteria to macrophages, as well as their mannose-binding activity, was similar, whereas in the exponential-phase bacteria they were markedly reduced. The results show a linear relation between the two parameters ( R = 0.98, P < 0.001). The internalization of the filamentous cells attached to macrophages during 45 min of incubation was much less efficient (20%) compared to that of exponential-phase, stationary-phase, or antibody-coated filamentous bacteria (90%). The results indicate that the mannose-binding activity of E. coli determines the recognition of the organisms by phagocytes. They further suggest that administration of β-lactam antibiotics may impair elimination of certain pathogenic bacteria by inducing the formation of filaments which are inefficiently internalized by the host's phagocytic cells.

The effects of D- and L-threo-chloramphenicol on the early development of the chick embryo

Development ◽  
1965 ◽  
Vol 13 (3) ◽  
pp. 341-356
Author(s):  
F. S. Billett ◽  
Rosalba Collini ◽  
Louie Hamilton
Keyword(s):  
Protein Synthesis ◽  
Amino Acid ◽  
Chick Embryo ◽  
Messenger Rna ◽  
Mammalian Cells ◽  
Animal Cells ◽  
Inhibit Protein Synthesis ◽  
Acid Complex ◽  
Amino Acid Complex ◽  
Bacterial Systems

In many bacterial systems chloramphenicol has been shown to inhibit protein synthesis (Hahn & Wisseman, 1951; Gale & Folkes, 1953). The precise mechanism of this inhibition is not clear, although the evidence suggests that the interaction of the soluble RNA-amino acid complex with the ribosomes is prevented because the attachment of the messenger RNA to the ribosomes is itself impaired (Lacks & Gros, 1959; Nathans & Lipman, 1961; Jardetsky & Julian, 1964; Julian & Jardetsky, 1964). In contrast to its effect on bacterial systems, chloramphenicol has been reported to have little or no action on the protein synthesis by cell-free extracts of mammalian cells (Rendi, 1959; Ehrenstein & Lipmann, 1961). A basis for this resistance has been proposed by Vazquez (1964), who finds that whereas bacterial ribosomes bind chloramphenicol, ribosomes from other organisms do not. Nevertheless, it cannot be stated with any confidence that chloramphenicol has no effect on the protein synthesis of animal cells.

scholarly journals POLARITY IN SEGMENTS OF THE ESCHERICHIA COLI trp OPERON WITH DELETED INTRAOPERONIC TRANSLATIONAL INITIATION SIGNALS

Genetics ◽  
1975 ◽  
Vol 80 (4) ◽  
pp. 651-666
Author(s):  
Yasunobu Kano ◽  
Fumio Imamoto
Keyword(s):  
Escherichia Coli ◽  
Translation Initiation ◽  
Nonsense Mutation ◽  
Messenger Rna ◽  
Distal Part ◽  
High Efficiency ◽  
Translational Initiation ◽  
Transcriptional Termination ◽  
Trp Operon

ABSTRACT The effect of deletion of the operator-distal genes of the trp operon, including the trpE-trpD intercistronic punctuation point, on the degree of transcriptional polarity (in this case the effect of a nonsense mutation on the level of mRNA from the distal part of the very gene where the mutation is located) was investigated. Double mutants which contain a nonsense mutation and a deletion in trpE were constructed, and the degree of transcriptional polarity was estimated by the decrease in messenger RNA for the operator-distal trpE beyond the nonsense mutation, as well as by the production of truncated messenger RNA for the region of trpE proximal to the nonsense mutation. The content of mRNA of operator-distal trpE and the size of the mRNA of operator-proximal trpE of the double mutants show that transcriptional polarity is not relaxed as a function of distance of the nonsense mutation from the operator-distal end of the trpE segment (at which the subsequent high efficiency translational initiation signal has been deleted). These findings are consistent with the conclusion that the degree of polarity depends on the distance of the nonsense mutation fro mthe subsequent translation initiation signal, but not on its distance from the operator-distal end, including possible translational or transcriptional termination signals

scholarly journals Studies on deoxyribonucleic acid-dependent ribonucleic acid polymerase from Escherichia coli. Variations of the enzyme activity during growth

1972 ◽  
Vol 129 (2) ◽  
pp. 291-299 ◽  
Author(s):  
K. A. Abraham ◽  
K. J. Andersen ◽  
A. Rognes
Keyword(s):  
Escherichia Coli ◽  
Stationary Phase ◽  
Stationary Phases ◽  
Bacteriophage T4 ◽  
Polymerase Activity ◽  
Exponential Phase ◽  
Enzyme Preparations ◽  
Rna Polymerase Activity ◽  
Enzyme Molecules ◽  
Cellular Dna

1. RNA polymerase activity of Escherichia coli extracts prepared from cells in exponential and stationary phases of growth, when measured in the presence and absence of external template, showed significant qualitative differences. 2. In both extracts, polymerase activity was higher when assayed with external template, suggesting the presence of a pool of enzyme not bound to cellular DNA. 3. In the crude extract, the fraction of enzyme bound to cellular DNA is higher during the exponential phase of growth. 4. A method is described for the purification of enzyme molecules not tightly bound to cellular DNA from exponential- and stationary-phase cultures. 5. Purified enzyme preparations showed differences in template requirement and subunit composition. 6. On phosphocellulose chromatography of stationary-phase enzyme, a major portion of polymerase activity eluted from the column with 0.25m-KCl. In the case of exponential-phase enzyme, polymerase activity eluted from a phosphocellulose column mainly with 0.35m-KCl. 7. Enzyme assays done with excess of bacteriophage T4 DNA showed a strong inhibition of stationary-phase enzyme by this template. The exponential-phase enzyme was only slightly inhibited by excess of bacteriophage T4 DNA.

scholarly journals Coordinated Hibernation of Transcriptional and Translational Apparatus during Growth Transition ofEscherichia colito Stationary Phase

mSystems ◽  
2018 ◽  
Vol 3 (5) ◽  
Author(s):  
Hideji Yoshida ◽  
Tomohiro Shimada ◽  
Akira Ishihama
Keyword(s):  
Stationary Phase ◽  
Sigma Factor ◽  
Exponential Phase ◽  
Screening System ◽  
Content Type ◽  
Genome Expression ◽  
70S Ribosome ◽  
K 12 ◽  
Sigma Subunit ◽  
Translational Apparatus

ABSTRACTIn the process ofEscherichia coliK-12 growth from exponential phase to stationary, marked alteration takes place in the pattern of overall genome expression through modulation of both parts of the transcriptional and translational apparatus. In transcription, the sigma subunit with promoter recognition properties is replaced from the growth-related factor RpoD by the stationary-phase-specific factor RpoS. The unused RpoD is stored by binding with the anti-sigma factor Rsd. In translation, the functional 70S ribosome is converted to inactive 100S dimers through binding with the ribosome modulation factor (RMF). Up to the present time, the regulatory mechanisms of expression of these two critical proteins, Rsd and RMF, have remained totally unsolved. In this study, attempts were made to identify the whole set of transcription factors involved in transcription regulation of thersdandrmfgenes using the newly developed promoter-specific transcription factor (PS-TF) screening system. In the first screening, 74 candidate TFs with binding activity to both of thersdandrmfpromoters were selected from a total of 194 purified TFs. After 6 cycles of screening, we selected 5 stress response TFs, ArcA, McbR, RcdA, SdiA, and SlyA, for detailed analysisin vitroandin vivoof their regulatory roles. Results indicated that bothrsdandrmfpromoters are repressed by ArcA and activated by McbR, RcdA, SdiA, and SlyA. We propose the involvement of a number of TFs in simultaneous and coordinated regulation of the transcriptional and translational apparatus. By using genomic SELEX (gSELEX) screening, each of the five TFs was found to regulate not only thersdandrmfgenes but also a variety of genes for growth and survival.IMPORTANCEDuring the growth transition ofE. colifrom exponential phase to stationary, the genome expression pattern is altered markedly. For this alteration, the transcription apparatus is altered by binding of anti-sigma factor Rsd to the RpoD sigma factor for sigma factor replacement, while the translation machinery is modulated by binding of RMF to 70S ribosome to form inactive ribosome dimer. Using the PS-TF screening system, a number of TFs were found to bind to both thersdandrmfpromoters, of which the regulatory roles of 5 representative TFs (one repressor ArcA and the four activators McbR, RcdA, SdiA, and SlyA) were analyzed in detail. The results altogether indicated the involvement of a common set of TFs, each sensing a specific environmental condition, in coordinated hibernation of the transcriptional and translational apparatus for adaptation and survival under stress conditions.

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