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  • Protein synthesis
  • Springer  (26)
  • American Institute of Physics (AIP)
  • Blackwell Publishing Ltd
  • 1980-1984  (26)
  • 1983  (6)
  • 1980  (20)
Collection
Publisher
  • Springer  (26)
  • American Institute of Physics (AIP)
  • Blackwell Publishing Ltd
Years
  • 1980-1984  (26)
Year
  • 1
    ISSN: 1432-2048
    Keywords: Gibberellin and protein synthesis ; Isocitrate-lyase ; mRNA ; Polysome ; Protein synthesis ; Ribonuclease activity ; Ricinus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The amount of protein synthesis in germinating castor-bean seeds has been estimated by the quantitative and qualitative exmainatin of polysomes from the seeds in the presence and absence of gibberellic acid (GA3). Careful optimisation of polysome extraction procedures was required to minimise the ribonuclease activity in the extracts. Ribonuclease activity in seed extracts increased fourfold over the first 5 d of germination. Gibberellic acid stimulated polysome formation about twofold during the first 4 d of germination. It also stimulated the amount of mRNA associated with polysomes by about twofold during the first 3 d of germination. Between days 1 and 5 of germination, polysome formation was primarily limited by mRNA availability. During the period 0–24 h, polysome formation was independent of mRNA levles. The increase in enzyme activities stimulated by GA3 was probably the result of an increase in the amount of cellular mRNA. No evidence was obtained for an action of GA3 on translation other than on the increased production of RNA. Examination of the recruitment of isocitrate-lyase mRNA into polysomes showed that GA3 did not specifically stimulate production of this enzyme.
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  • 2
    ISSN: 1432-041X
    Keywords: Mouse embryogenesis ; Cytochalasin B ; Polyploid ; Chromosome replication ; Protein synthesis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The cleavage of fertilized mouse eggs was prevented during cytochalasin B incubation and consequently these eggs became tetraploid the following day during in vitro culture. When the eggs were cultured further in normal medium, they cleaved and gave rise to tetraploid blastocysts. Protein synthesis was analysed in these embryos at different developmental stages using two-dimensional polyacrylamide gel electrophoresis. The protein synthesis pattern of one-cell tetraploid eggs was intermediate between those of normal one- and two-cell embryos. Tetraploid two-cell embryos expressed protein sets equivalent to those of untreated four-cell embryos, and tetraploid four-cell embryos synthesized proteins similar to those of four- to eight-cell controls. At subsequent pre-implantation stages the asynchrony was no longer detectable. When fertilized eggs were cultured continuously in the presence of cytochalasin B, they became tetraploid, octoploid and more and more polyploid without cleavage occurring. The protein synthesis patterns expressed by these one-cell polyploid eggs did not resemble that of normal fertilized eggs, but were similar to those of cleaving control embryos and blastocysts of equivalent age and nuclear division. These results strongly suggest that in early mouse embryos stage-specific translation is temporally correlated with chromosome replication (karyokinesis) and independent of cell division (cytokinesis) or cell interaction.
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  • 3
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    Archives of microbiology 135 (1983), S. 8-11 
    ISSN: 1432-072X
    Keywords: Protein synthesis ; Antibiotics ; Bacterial ribosomes ; Cell-free systems ; Peptidyltransferase ; Synergimycins
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Although virginiamycin components VM and VS are known to exert in vivo a synergistic inhibition of bacterial growth and viability, in cell-free systems only VM has proven active. In the present work, the in vivo and in vitro activities of VM and VS on Bacillus subtilis have been compared. Peptide formation in homogenates of bacteria previously incubated with either VM or VS was found strongly repressed; the 2 components acted synergistically. Ribosomes were fully responsible for this effect, as shown by mixed reconstitution experiments. On the other hand, cytoplasm from control bacteria disrupted in 10 mM Mg2+ buffer was refractory to in vitro inhibition by virginiamycin, whereas ribosomes prepared in 1 mM Mg2+ were sensitive to VM. VS was inactive on poly(U)-directed poly(phenylalanine) formation, and displayed some activity on the poly(A)-poly(lysine) system. In a cell-free system from Bacillus subtilis infected with phage 2C, both VM and VS were active and blocked synergistically protein synthesis in vitro. When the host cells were incubated with VS and the corresponding homogenate was then treated with VM, a complete inhibition of protein synthesis was observed. The present work, thus, describes the techniques for investigating the in vivo and in vitro action of synergimycins on the same organism, and for reproducing in vitro the synergistic interaction of type A and B components previously observed only in vivo.
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  • 4
    ISSN: 1432-2048
    Keywords: Mutant (Petunia) ; Northern blotting and hybridization ; Petunia ; Plastid gene expression ; Protein synthesis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract We have analyzed the morphology and gene expression in plastids of a yellow-green leaf mutant of Petunia hybrida (E 5059). Under normal light intensities (20,000 lx), yellow-green leaves develop with a typical proplastid morphology (few membranes, incomplete stacking). When such plants are grown under low light intensities (3,000 lx), the newly formed leaves are green. The plastids in these green leaves have a wild-type like chloroplast morphology (thylakoids and grana structure). Pre-existing green leaves remain green in 20,000 lx, indicating that chlorophyll is not degraded. An analysis of polypeptides synthesized in isolated plastids from the yellow-green and green leaves of this mutant plant shows several differences. In the yellow-green leaf plastids only a very small amount of the large subunit of ribulose-1,5-bisphosphate carboxylase (RuBPCase) is present, while in green plastids this polypeptide is present in much higher amounts. Hybridization experiments indicated that in plastids from the yellow-green leaves the mRNA coding for the large subunit polypeptide is present in much lower amounts than in plastids from the 3,000 lx green leaves of this mutant or in chloroplasts from wild type plants. These results indicate regulation at the mRNA level. Furthermore, in yellow-green leaf plastids eleven polypeptides are present with high molecular wieght (higher than 67,000 d). Five of them are synthesized by the yellow-green leaf plastid itself. Such high molecular weight polypeptides are also synthesized by proplastids isolated from white petunia cell suspension cultures, but are not synthesized by 3,000 lx green leaf plastids, or by isolated normal leaf chloroplasts. These results indicate that the synthesis of these polypeptides is specific for the proplastid stage of chloroplast biogenesis.
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  • 5
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    Journal of bioenergetics and biomembranes 15 (1983), S. 379-394 
    ISSN: 1573-6881
    Keywords: Protein synthesis ; energy transduction ; salinity adaptation ; gill mitochondria
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Physics
    Notes: Abstract Exposure of freshwater fish to saline conditions brings about somewhat drastic changes in the mitochondrial energy metabolism. These include abolition of oxidative phosphorylation, ATP-induced contraction of swollen mitochondria and transhydrogenase activity. On the other hand the endogenous calcium levels and protein synthetic capacity are elevated.In vitro protein synthesis by mitochondria from freshwater and stressed fish shows qualitative and quantitative variations. Effluxing the excess calcium by treatment with NaCl or inhibiting the protein synthesis by chloramphenicol in stressed mitochondria restores almost all the functions. It is proposed that the energy potential formed by the mitochondrial membrane is channelized to perform different functions and that the ratio of channelization can be altered to suit the needs of the cell.
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  • 6
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    Cell & tissue research 228 (1983), S. 75-84 
    ISSN: 1432-0878
    Keywords: Organ culture ; Suckling mouse, small intestine ; DNA synthesis ; Protein synthesis ; Brush border enzymes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Proximal and distal parts of the small intestine of 8-day-old suckling mice can best be maintained for 48h in a serum-free organ culture system, Leibovitz L-15, at room air and room temperature. As determined by light and electron microscopy, the villous architecture was preserved as well as the classical ultrastructure of the enterocytes. Incorporation of 3H-thymidine and 3H-leucine continued during the culture period, reflecting a sustained synthesis of DNA and proteins for at least 48 h. The hydrolytic activities of the brushborder membrane, namely of lactase (L), trehalase (T), glucoamylase (GA) and alkaline phosphatase (AlPase) were measured in the explants as well as the culture medium. The overall enzymatic activities were increased as compared to the controls. In the tissue, L, GA and T activities remained stable or even increased during culture while in the medium an accumulation of enzymatic activities was noted especially for GA an AlPase. These results show that the morphological as well as the functional integrity of the mucosa is preserved for at least 48 h when small intestine of suckling mice is cultured in a serum-free medium.
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  • 7
    ISSN: 1432-2048
    Keywords: mRNA ; Protein synthesis ; Pisum ; Seeds (translation) ; Translation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Extracts from the primary axes of dry pea (Pisum sativum L.) seeds are able to perform an initiation-dependent translation of exogenous mRNA. SDS polyacrylamide gel electrophoresis of the products synthesized under direction of alfalfa mosaic virus RNA (AMV-RNA) and tobacco mosaic virus RNA (TMV-RNA) shows that the fidelity of translation in this pea system is at least as high as in a wheat embryo cell-free protein synthesizing system. The endogenous messengers are also efficiently translated in extracts from the primary axes of pea seeds. The direct translation of these messengers in a homologous cell-free system may be of interest for a study of the products coded for by the long-lived messengers present in this plant.
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  • 8
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    Planta 147 (1980), S. 307-311 
    ISSN: 1432-2048
    Keywords: Embryo ; Protein synthesis ; Scutellum ; Secale ; Translation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Some botanical aspects of cell-free protein synthesizing systems from cereal embryos have been investigated. The composition of the starting material determines both the stability and translation fidelity of the cell-free extracts. The active components of the extracts originate exclusively from the primary axes. Contamination with scutellum fragments does not affect the initial activity but results in a reduced stability. The presence of endosperm particles in the starting material leads to a strong decrease of the overall activity of the extracts and a loss of the capacity to synthesize large polypeptides.
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  • 9
    ISSN: 1432-2048
    Keywords: Pisum ; Polyribosomes ; Post translational modifications ; Protein synthesis ; Storage proteins
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Polypeptide material has been immunoprecipitated by antivicilin antibodies from translation products of polyribosomes and poly(A)-rich RNA isolated from developing seeds of Pisum sativum in the wheat germ and reticulocyte lysate cell-free synthesis systems. Analysis of this material by SDS-PAGE shows it to consist of three bands, of molecular weights 70,000, 50,000 and 47,000. The in vitro vicilin polypeptides of 70,000 and 50,000 mol. wt. have been shown to be very similar to the 70,000 and 50,000 mol. wt. subunits of vicilin by specific immunoprecipitation, and behaviour on treatment with cyanogen bromide and trypsin. The 50,000 mol. wt. in vitro vicilin polypeptide contains no significant extra sequence compared to the 50,000 mol. wt. vicilin subunit. The 47,000 mol. wt. in vitro vicilin polypeptide has no corresponding subunit in vicilin from mature seeds, but a 47,000 mol. wt. subunit is present in vicilin isolated from developing seeds. Comparison of translation products from polysomes isolated from seeds at middle and late stages of development shows that synthesis of the 50,000 and 47,000 mol. wt., but not 70,000 mol. wt. polypeptides is very much reduced at late stages of development. These results are discussed with reference to the nature of the vicilin fraction.
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  • 10
    ISSN: 1432-2048
    Keywords: mRNA ; Nicotiana ; Protein synthesis ; Ribulose-1,5-bisphosphate carboxylase ; RNA (messenger) ; Translation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The products synthesized in vitro by messenger RNA (mRNA) extracted from Nicotiana sylvestris were analyzed by electrophoresis on polyacrylamide slab gels. Only three of the major polypeptides synthesized are considered here: P55, P32, and P20. P55 and P32 were translated from chloroplast mRNA. P55 corresponds to the large subunit of ribulose-1,5-bisphosphate (RuP2) carboxylase; P32 is probably a chloroplast membrane protein. P20, the polypeptide synthesized from cytoplasmic poly(A)+ RNA, is the precursor of the small subunit of RuP2 carboxylase. The balance between P20 and P32, in which their relative proportions varied inversely, was regulated by the age of the leaves and the time of illumination; we took advantage of this phenomenon to isolate the mRNA from the small subunit in relatively large amounts. This mRNA has a molecular weight of 350,000.
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  • 11
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    Planta 148 (1980), S. 491-497 
    ISSN: 1432-2048
    Keywords: Leaves (polysomes) ; Nicotiana ; Polysomes ; Poly(A)+ RNA ; Protein synthesis ; RNA (polysomal, polyA+)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The isolation of intact polysomes from leaves of tobacco (Nicotiana tabacum L.) is dependent on the age and state of development of leaves. Undegraded polysomes from young leaves in the early stages of expansion can be isolated easily by extracting the leaves in ice-cold extraction buffer (200 mM tris(hydroxymethyl)aminomethylmethane(Tris)-HCl, pH 9.0; 400 mM KCl; 200 mM sucrose; 35 mM MgCl2). Medium-size leaves give best yields of undegraded polysomes when extractions are carried out in the above buffer and in the presence of ethyleneglycol-bis-(β-amino-ethyl ether)-N,N′-tetracetic acid (EGTA) and mercaptoethanol. Isolation of polysomes from large, nearly fully expanded (mature) leaves requires all of the above plus diethyldithiocarbamate (DIECA) in the extraction medium. An extraction medium consisting of 25 mM EGTA, 0.01 M mercaptoethanol, 25 mM DIECA and 0.5% of the nonionic detergent, Nonidet-P40 (NP 40) was found to be very suitable for extraction of polysomes from all developmental stages of leaves. The polysomes extracted in the above medium showed active translation of protein in the wheat-germ in-vitro protein-synthesizing system. The translational products were similar when translations were carried out directly with polysomes or polysomal RNA, or polysomal poly(A)+ RNA from tobacco leaves. Poly(A)− polysomal RNA was a poor template in the in-vitro wheat-germ system.
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  • 12
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    Planta 148 (1980), S. 491-497 
    ISSN: 1432-2048
    Keywords: Leaves (polysomes) ; Nicotiana ; Polysomes ; Poly(A)+ RNA ; Protein synthesis ; RNA (polysomal, polyA+)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The isolation of intact polysomes from leaves of tobacco (Nicotiana tabacum L.) is dependent on the age and state of development of leaves. Undegraded polysomes from young leaves in the early stages of expansion can be isolated easily by extracting the leaves in ice-cold extraction buffer (200 mM tris(hydroxymethyl)aminomethylmethane(Tris)-HCl, pH 9.0; 400 mM KCl; 200 mM sucrose; 35 mM MgCl2). Medium-size leaves give best yields of undegraded polysomes when extractions are carried out in the above buffer and in the presence of ethyleneglycol-bis-(β-amino-ethyl ether)-N,N′-tetracetic acid (EGTA) and mercaptoethanol. Isolation of polysomes from large, nearly fully expanded (mature) leaves requires all of the above plus diethyldithiocarbamate (DIECA) in the extraction medium. An extraction medium consisting of 25 mM EGTA, 0.01 M mercaptoethanol, 25 mM DIECA and 0.5% of the nonionic detergent, Nonidet-P40 (NP 40) was found to be very suitable for extraction of polysomes from all developmental stages of leaves. The polysomes extracted in the above medium showed active translation of protein in the wheat-germ in-vitro protein-synthesizing system. The translational products were similar when translations were carried out directly with polysomes or polysomal RNA, or polysomal poly(A)+ RNA from tobacco leaves. Poly(A)− polysomal RNA was a poor template in the in-vitro wheat-germ system.
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  • 13
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    Planta 148 (1980), S. 429-436 
    ISSN: 1432-2048
    Keywords: Auxin action ; Avena ; Coleoptile ; Protein synthesis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Synthesis of growth-limiting proteins (GLP) is required for continued auxin-induced elongation of oat (Avena sativa L.) coleoptiles. In order to determine whether GLP synthesis is dependent or independent of auxin, a double-labeling ratio technique, coupled with disc-gel electrophoresis, has been used to assess the effect of auxin on the pattern of protein synthesis. Sections were peeled to enhance amino-acid uptake; proteins were labeled with [14C]- or [3H] leucine in the presence or absence of indole-3-acetic acid for 40 min to 6 h, and were separated into soluble, membrane-associated, and wall-associated fractions. Regardless of the conditions used, or the protein fraction examined, no changes in response to auxin were detected in the pattern of protein synthesis. In order to escape detection by this technique an auxin-induced protein would have to comprise less than 0.75% of the total newly synthesized protein. Thus the synthesis of GLP appears to be independent of auxin. The same technique has been used to follow protein turnover. During the chase, proteins are initially degraded at an average rate of 8% h−1, and some protein bands showed as much as 14% h−1 degradation. No protein was detected which had a turnover rate as rapid as the GLP.
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  • 14
    ISSN: 1432-2048
    Keywords: mRNA ; Protein synthesis ; Protoplasts ; Nicotiana ; Translation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Studies of proteins synthesized in vitro by messenger RNA (mRNA) extracted from tobacco protoplasts showed that the changes in protein synthesis and especially the lack of certain proteins observed previously in isolated protoplasts did not result from a failure of translation.
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  • 15
    ISSN: 1432-2048
    Keywords: Embryo (germination) ; Germination (embryos) ; Protein synthesis ; RNA ; Triticum ; Vigour
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A study has been made of the RNA and protein synthesising systems of wheat embryos isolated from seed lots having high viability but differing in vigour. The rate of RNA and protein synthesis in wheat embryos during the early hours of germination is related to the vigour of the seed lot. The imposition of a stress factor, in the nature of a sub-optimal germination temperature, during germination of isolated wheat embryos magnifies the differences in rates of protein and RNA synthesis between high and low vigour seed. Using cell-free protein synthesising systems it has been demonstrated that an important difference between high and low vigour embryos lies in the relative levels of messenger RNA in the embryo. High vigour embryos contain relatively higher levels of poly A+-RNA (i.e. potential mRNA species) than lower vigour embryos and furthermore the level of poly A+-RNA in high vigour embryos increases during early germination whilst in lower vigour embryos the level decreases. The difference in poly A+-RNA levels accounts, at least partially, for the differences in rates of protein synthesis observed between embryos from high and low vigour wheat seed during early germination at both optimal and sub-optimal germination temperatures.
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  • 16
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    Planta 148 (1980), S. 429-436 
    ISSN: 1432-2048
    Keywords: Auxin action ; Avena ; Coleoptile ; Protein synthesis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Synthesis of growth-limiting proteins (GLP) is required for continued auxin-induced elongation of oat (Avena sativa L.) coleoptiles. In order to determine whether GLP synthesis is dependent or independent of auxin, a double-labeling ratio technique, coupled with disc-gel electrophoresis, has been used to assess the effect of auxin on the pattern of protein synthesis. Sections were peeled to enhance amino-acid uptake; proteins were labeled with [14C]- or [3H] leucine in the presence or absence of indole-3-acetic acid for 40 min to 6 h, and were separated into soluble, membrane-associated, and wall-associated fractions. Regardless of the conditions used, or the protein fraction examined, no changes in response to auxin were detected in the pattern of protein synthesis. In order to escape detection by this technique an auxin-induced protein would have to comprise less than 0.75% of the total newly synthesized protein. Thus the synthesis of GLP appears to be independent of auxin. The same technique has been used to follow protein turnover. During the chase, proteins are initially degraded at an average rate of 8% h−1, and some protein bands showed as much as 14% h−1 degradation. No protein was detected which had a turnover rate as rapid as the GLP.
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  • 17
    ISSN: 1432-2048
    Keywords: mRNA ; Protein synthesis ; Protoplasts ; Nicotiana ; Translation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Studies of proteins synthesized in vitro by messenger RNA (mRNA) extracted from tobacco protoplasts showed that the changes in protein synthesis and especially the lack of certain proteins observed previously in isolated protoplasts did not result from a failure of translation.
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  • 18
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    Planta 149 (1980), S. 262-268 
    ISSN: 1432-2048
    Keywords: Hordeum ; Polyribosomes ; Protein synthesis ; RNA ; Seeds ; Storage proteins
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Membrane-bound polysomes were isolated from developing endosperms of barley (Hordeum vulgare L.) and shown to support the synthesis of trichloroacetic acid-insoluble material by an in vitro wheat germ protein synthesis system. The mRNA associated with the polysomes was separated from the ribosomes by affinity chromatography on oligo-dT cellulose and was also shown to support in vitro protein synthesis. The poly-A+ RNA isolated contained material of between 0.55 and 2.55 kilobases in length with about 6% poly A. The products of in vitro protein synthesis resembled hordeins (the prolamin storage proteins of the barley endosperm) in that they were predominantly soluble in 55% propan-2-ol, contained a low proportion of lysine as compared with leucine and had similar, but not identical, electrophoretic properties. The differences in the electrophoretic behaviour between the products of poly-A+ RNA translation and authentic hordeins is suggested to be due to the presence of an extra (leader?) sequence on the former.
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  • 19
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    Journal of molecular evolution 15 (1980), S. 339-345 
    ISSN: 1432-1432
    Keywords: Protein synthesis ; Origin ; Activation ; Initiation ; pKa
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The data presented in this paper show that the ease of non-enzymatic activation of carboxylic acids by ATP at pH 5 varies directly with the pKa of the carboxyl group, and is consistent with the idea that it is the protonated form of the carboxyl group which participates in the activation reaction. Consequently, since most N-blocked amino acids have higher pKa's than do their unblocked forms, they are activated more readily, and we have demonstrated that this principle applies to peptides as well,which are activated more rapidly than single amino acids. We propose that this fact may be partly responsible for the origin of two important features still observed in contemporary protein synthesis: (1) initiation in prokaryotes is accomplished with an N-blocked amino acid, and (2) elongation in all living systems occurs at the carboxyl end of the growing peptide.
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  • 20
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    Development genes and evolution 189 (1980), S. 215-219 
    ISSN: 1432-041X
    Keywords: Mouse eggs ; Microsurgical enucleation ; Maternal mRNA ; Protein synthesis ; 2-Dimensional polyacrylamide gel electrophoresis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Fertilized and unfertilized C57BL/6J eggs were microsurgically enucleated and then analyzed for their capacity to synthesize proteins using 2-dimensional polyacrylamide gel electrophoresis. In both types of enucleated eggs (cytoplasts), protein synthesis continued and was still detected up to three days in culture. Shortly after enucleation, the pattern of polypeptides remained similar to the respective non-operated control eggs but it later became gradually reduced in intensity and complexity. After two days of culture the appearance of some new proteins typical for 2-cell embryos was observed in enucleated fertilized eggs only. Our findings suggest that maternal mRNA stored during oogenesis is utilized during the preimplantation period.
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  • 21
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    Current genetics 2 (1980), S. 61-67 
    ISSN: 1432-0983
    Keywords: Axenomycin ; Ribosome genetics ; Yeast ; Protein synthesis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Axenomycin inhibits protein synthesis in vivo and in vitro in Saccharomyces cerevisiae. The antibiotic acts by binding to ribosomes, most probably to the large ribosomal subunit. Mutant strains resistant to axenomycin appear to contain ribosomes that are not inhibited by the antibiotic. The responsible gene has been mapped on the VII chromosome between the centromere and the leu1 gene.
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  • 22
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    Environmental biology of fishes 5 (1980), S. 67-70 
    ISSN: 1573-5133
    Keywords: Protein synthesis ; Physiology ; Temperature ; Primary production ; Reproduction ; Body weight ; Fish
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Synopsis Black crappie (Pomoxis nigromaculatus) were collected weekly from a natural lake during the period mid-April to mid-September. The fish were weighed, state of maturity determined and RNA-DNA ratio of white muscle was measured. Water temperature and primary production were measured in the lake. RNA-DNA ratio declined during the spawning season, reaching a low in mid-May, then increased steadily during the remainder of the year. RNA-DNA ratio was significantly correlated with body weight. The correlation was improved if RNA-DNA ratio was paired with weight for the following week. The correlation was further improved when the spawning season was removed from the data set. Both weight and RNA-DNA ratios were significantly correlated with water temperature, as expected. The correlations were again improved if water temperature was paired with weight and RNA-DNA values for the following week. Weight and RNA-DNA ratio were also correlated with primary production when the correlation was made with concurrent values, and the correlations were improved when RNA-DNA ratio or weight were paired with primary production values for the previous month. RNA-DNA ratio was determined to be a useful predictor of skeletal muscle growth in natural populations of fish over short (ca. one week) time intervals.
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  • 23
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    Protoplasma 103 (1980), S. 189-200 
    ISSN: 1615-6102
    Keywords: ATP content ; ATP turnover ; DMSO ; Protein synthesis ; Tetrahymena
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The content of ATP in cells exposed for 1 hour to 2.5% and 7.5% dimethyl sulphoxide (DMSO) was 90% and about 80%, respectively, of that in control cells. This difference of about 10% in the ATP content cannot explain the previously reported cessation of food vacuole formation in 7.5% DMSO and the uninhibited function in 2.5% DMSO (Nilsson 1974). However, DMSO had a dose-dependent effect on the rate of turnover of ATP in cell extracts, thus the amount of ATP expended per unit time in 7.5% DMSO is only 60% of that expended by extracts of control cells. The rate of protein synthesis was studied by electron microscope autoradiography which revealed considerably less labelled material in DMSO-treated cells than in control cells. Semi-quantitative estimates showed that cells in 2.5%, 5%, and 7.5% DMSO had a rate of incorporation of the labelled amino acid corresponding to 38%, 31%, and 51%, respectively, of that of control cells; the seemingly high rate of incorporation in 7.5% DMSO may reflect a low internal pool of amino acids in these cells. An additional fine structural detail is the induction of intranuclear fibrous bundles in all concentrations of DMSO. The findings are in accord with a random interference of DMSO, presumably by inducing conformational changes in some macromolecules which affect their cellular function.
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  • 24
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    Cell & tissue research 208 (1980), S. 261-281 
    ISSN: 1432-0878
    Keywords: Choroid plexus ; Ependyma ; Apocrine secretion ; Protein synthesis ; Electron microscope autoradiography
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Description / Table of Contents: Zusammenfassung Licht- (LM-ARG) und elektronenmikroskopische (EMARG) Autoradiographien des Plexus chorioideus und des Ependyms von jungen Ratten wurden nach der Injektion von Tritium-markierten Aminosäuren angefertigt. Die Ratten wurden in Zeitabständen von 5, 10, 30, 60 min und 16 h getötet. Intracelluläre Proteinsynthese und Transport wurden im Plexus chorioideus der lateralen und des vierten Ventrikels mit quantitativer Autoradiographie bestimmt. Autoradiographische Experimente wurden auch an kultiviertem Plexus chorioideus-Gewebe durchgeführt. Diese Serie wurde nach eintägigem Wachstum in vitro für 1 h mit 3H-Phenylalanin markiert, anschließend gewaschen und für weitere Zeitperioden kultiviert. Hohe Inkorporation der markierten Substanzen wurde in gestielten und freien “blebs” des Plexus chorioideus und des Ependyms in vivo und des Plexus chorioideus in vitro gefunden. Dieses Ergebnis wurde als ein physiologisch bedeutender Mechanismus des Protein-Transportes (apokrine Sekretion) von den Epithelzellen in den Liquor cerebrospinalis gedeutet.
    Notes: Summary Light (LM-ARG) and electron microscope (EM-ARG) autoradiographs were prepared from immature rat choroid plexus and ependyma at 5, 10, 30, and 60 min and 16 h following intraperitoneal administration of [3H]- labeled amino acid mixtures. Intracellular protein synthesis and transport were ascertained in lateral and fourth ventricle choroid plexus epithelium by quantitative EM-ARG at the several post-injection intervals. ARG were also prepared from choroid plexuses cultured for one day, pulse labeled for one hour and reincubated for various periods in nonradioactive media. Significant labeling of both attached and free apical protrusions (blebs) was observed in both choroid plexus and ependyma in vivo and in choroid plexus in vitro. This phenomenon was interpreted as a physiologically significant mechanism for protein transport (apocrine secretion) by epithelia into the cerebrospinal fluid (CSF).
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  • 25
    ISSN: 1432-0878
    Keywords: Human heart ; Cardiac ultrastructure ; Sarcomerogenesis ; Protein synthesis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The origin of cardiac myofibrils in cells from the atrial wall in human embryos was studied. Z-band substance appears throughout the cytoplasm as irregular electron dense patches in a network of thin filaments. The thin and thick filaments are synthesized as separate units in the sarcoplasm and are later aggregated into myofibrils. Complexes of Z substance and thin filaments occur numerously at different stages of myofibrillar organisation. Thick filaments are formed in close proximity to free ribosomes and are later incorporated in an hexagonal pattern into the Z-band/thin filament complex.
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  • 26
    Electronic Resource
    Electronic Resource
    Springer
    Cell & tissue research 207 (1980), S. 1-11 
    ISSN: 1432-0878
    Keywords: Heart(rat) ; Ultrastructural radioautography ; Protein synthesis ; Atrial specific granules
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Sections of atrial cardiocytes from young rats were subjected to radioautography after a single intravenous injection of L-leucine-4,5 3H to identify the sites of synthesis and to follow the migration of newly-formed proteins. As early as 2 min after injection of L-leucine 3H, the label was highest in the rough endoplasmic reticulum (RER), suggesting that cisternal ribosomes are sites of protein synthesis. By 5 min, most of the label had migrated from the RER to the Golgi complex. Some label was already present over specific granules by 2 min but the peak was reached at 1 h. By 4 h, the label over the specific granules had diminished, possibly indicating a release of newly-synthetized secretory material outside the cell. The label over myofilaments and Z-bands was relatively high at most time intervals, suggesting an early and important incorporation of leucine into the contractile and structural proteins of these organelles. The label over the cytosol was initially high and increased even further at 5 and 20 min but decreased to a very low level at 4 h. In contrast, the label over the cell surface rose continuously and peaked at 4 h. The pattern of increment of the label over the cell surface suggests that the newly-formed proteins of these sites are also synthetized in the RER, pass through the Golgi complex and are transported in the cytosol before reaching their destination.
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