scholarly journals PROTEIN SYNTHESIS BY ISOLATED PEA NUCLEOLI

1963 ◽  
Vol 18 (1) ◽  
pp. 41-50 ◽  
Author(s):  
Max L. Birnstiel ◽  
Beal B. Hyde
Keyword(s):  
Protein Synthesis ◽  
Amino Acid Mixture ◽  
Microscopic Investigation ◽  
Electron Microscopic Investigation ◽  
Nucleolar Protein ◽  
Acid Mixture ◽  
Electron Microscopic ◽  
Submicroscopic Structure ◽  
Acid And Base

A new method is described for the preparation of active, nucleus-free nucleoli and chromatin in relatively high purity and in sufficient quantities to permit biochemical and electron microscopic investigation. This method consists of disintegrating previously isolated nuclei by grinding with glass beads in an isotonic medium thus liberating structurally intact nucleoli and chromatin threads. Nucleoli and chromatin are then purified by differential centrifugation in Ficoll solutions. A study of the chemical composition, submicroscopic structure, and biological activity of the nucleolar preparation has been made. An equivalent study of the chromatin material has also been carried out in order to assess the significance of chromosomal contamination in nucleolar protein synthesis. The isolated nucleoli rapidly incorporate leucine-C14 into acid and base stable compounds in vitro. Such incorporation lasts for 20 minutes at 37°C and is enhanced by the addition of an energy-regenerating system and a complete amino acid mixture. It is independent of the nuclear Ph 5 enzymes. The bulk of the incorporated label is recovered in the residual, ribosome-like nucleolar protein fraction and a small percentage is found in the acid-extractable basic proteins. The rate of protein synthesis by isolated nucleoli is more rapid than that occurring in the chromatin fraction. This is taken as an additional proof that the nucleolus is the principal site of protein synthesis in the interphase pea nucleus.

Effect of Dietary Protein and Amino Acid Mixture on Protein Synthesis in vitro in Rat Liver

1974 ◽  
Vol 16 (6) ◽  
pp. 325-336 ◽  
Author(s):  
Alexandra von der Decken ◽  
Per T. Omstedt
Keyword(s):  
Protein Synthesis ◽  
Amino Acid ◽  
Rat Liver ◽  
Dietary Protein ◽  
Amino Acid Mixture ◽  
Acid Mixture

The effect of osmolarity on mouse parthenogenesis

Development ◽  
1974 ◽  
Vol 31 (2) ◽  
pp. 513-526
Author(s):  
M. H. Kaufman ◽  
M. A. H. Surani
Keyword(s):  
Protein Synthesis ◽  
Culture Medium ◽  
Culture Media ◽  
Polar Body ◽  
Amino Acid Mixture ◽  
Culture Conditions ◽  
Follicle Cells ◽  
Acid Mixture ◽  
Second Polar Body

Eggs from (C57B1 × A2G)F1 mice were activated by treatment with hyaluronidase, which removed the follicle cells, and cultured in vitro. Observations were made 6–8 h after hyaluronidase treatment to determine the frequency of activation and the types of parthenogenones induced. Cumulus-free eggs resulting from hyaluronidase treatment were incubated for 2¼ h in culture media of various osmolarities. The frequency of activation was found to be dependent on the postovulatory age of oocytes, while the types of parthenogenones induced were dependent on the osmolarity of the in vitro culture medium and their postovulatory age. Culture in low osmolar medium suppressed the extrusion of the second polar body (2PB). This decreased the incidence of haploid eggs with a single pronucleus and 2PB and immediately cleaved eggs from 97·5% to 42·3% of the activated population. Where 2PB extrusion had been suppressed, 97·4% of parthenogenones contained two haploid pronuclei. Very few were observed with a single and presumably diploid pronucleus. Serial observations from 11 to 18 h after hyaluronidase treatment were made on populations of activated eggs as they entered the first cleavage mitosis after 2¼ h incubation in medium either of normal (0·287 osmol) or low (0·168 osmol) osmolarity. A delay in the time of entry into the first cleavage mitosis similar to the duration of incubation in low osmolar medium was observed. Further, eggs were incubated in control and low osmolar culture media containing uniformly labelled [U-14C]amino acid mixture to examine the extent of protein synthesis in recently activated eggs subjected to these culture conditions. An hypothesis is presented to explain the effect of incubation in low osmolar culture medium in delaying the first cleavage mitosis.

Electron microscopy of barley root infection by the fungal pathogen Bipolaris sorokiniana

1991 ◽  
Vol 69 (12) ◽  
pp. 2724-2731 ◽  
Author(s):  
H. Carlson ◽  
U. Stenram ◽  
M. Gustafsson ◽  
H.-B. Jansson
Keyword(s):  
Cell Wall ◽  
Bipolaris Sorokiniana ◽  
Root Surface ◽  
Microscopic Investigation ◽  
Electron Microscopic Investigation ◽  
Barley Root ◽  
Outer Cortex ◽  
Electron Microscopic ◽  
Helminthosporium Sativum

An electron microscopic investigation of barley roots infected in vitro by Bipolaris sorokiniana showed the existence of an extracellular sheath on germ tubes and appressoria attached to the root surface. Growth of the fungus in the epidermis and outer cortex was predominantly intracellular, whereas in the inner cortex the hyphae observed were mainly intercellular. Hyphae could not be detected in the stele 24 or 72 h after inoculation. Enzymatic activity in the apex of penetration hyphae is a possible explanation of the electron-dense areas seen in host cell walls 72 h after inoculation. Separation of plasmalemma from cell wall and degeneration of host nuclei and mitochondria were other infection-induced changes commonly seen. A host response to fungal infection involved the development of papillae between the plasma membrane and cell wall of the plant as well as around fungal hyphae. Key words: Bipolaris sorokiniana, Cochliobolus sativus, Helminthosporium sativum, Hordeum vulgare, barley, root, microscopy.

scholarly journals Cytological, Biochemical, and Transcriptomic Analyses of a Novel Yellow Leaf Variation in a Paphiopedilum (Orchidaceae) SCBG COP15

Genes ◽  
2021 ◽  
Vol 13 (1) ◽  
pp. 71
Author(s):  
Ji Li ◽  
Kunlin Wu ◽  
Lin Li ◽  
Meina Wang ◽  
Lin Fang ◽  
...  
Keyword(s):  
Molecular Mechanisms ◽  
Chloroplast Ultrastructure ◽  
Microscopic Investigation ◽  
Electron Microscopic Investigation ◽  
Color Variation ◽  
Yellow Leaf ◽  
Electron Microscopic ◽  
Chl A ◽  
Leaf Variation

The genus Paphiopedilum, belonging to the Orchidaceae, has high ornamental value. Leaf variations can considerably improve the economic and horticultural value of the orchids. In the study, a yellow leaf mutant of a Paphiopedilum hybrid named P. SCBG COP15 was identified during the in vitro plant culture process; however, little is known about their molecular mechanisms. For this, RNA-seq libraries were created and used for the transcriptomic profiling of P. SCBG COP15 and the yellow mutant. The Chl a, Chl b, and carotenoid contents in the yellow leaves decreased by approximately 75.99%, 76.92%, and 56.83%, respectively, relative to the green leaves. Decreased chloroplasts per cell and abnormal chloroplast ultrastructure were observed by electron microscopic investigation in yellowing leaves; photosynthetic characteristics and Chl fluorescence parameters were also decreased in the mutant. Altogether, 34,492 unigenes were annotated by BLASTX; 1,835 DEGs were identified, consisting of 697 upregulated and 1138 downregulated DEGs. HEMA, CRD, CAO, and CHLE, involved in Chl biosynthesis, were predicted to be key genes responsible for leaf yellow coloration. Our findings provide an essential genetic resource for understanding the molecular mechanism of leaf color variation and breeding new varieties of Paphiopedilum with increased horticultural value.

scholarly journals PROTEIN SYNTHESIS IN SYNAPTOSOMAL FRACTIONS

1972 ◽  
Vol 52 (3) ◽  
pp. 526-535 ◽  
Author(s):  
P. Gambetti ◽  
L. A. Autilio-Gambetti ◽  
N. K. Gonatas ◽  
B. Shafer
Keyword(s):  
Protein Synthesis ◽  
Specific Activity ◽  
Mitochondrial Protein ◽  
Amino Acid Mixture ◽  
Acid Mixture ◽  
Mitochondrial Protein Synthesis ◽  
Synaptosomal Fraction ◽  
Tritiated Amino Acids ◽  
Vitro Protein

A quantitative ultrastructural radioautographic study of in vitro protein synthesis has been carried out in rat synaptosomal fractions incubated with tritiated leucine or a tritiated amino acid mixture. Analysis of grain density distribution demonstrated that presynaptic endings are labeled. 30–50% of the developed grains, representing tritiated amino acids incorporated into proteins, were related to presynaptic endings which accounted for 75–77% of the total processes. 34–45% of the grains were related to processes containing ribosomes which accounted for only 4–7% of the total processes. The relative specific activity of these ribosome-containing processes, some of which could be identified as postsynaptic elements, was up to ten times higher than that of the presynaptic ending. These findings indicate that protein synthesis takes place in vitro in presynaptic terminals although to a significantly lesser degree than that occurring in ribosome-containing processes, which, with other nonpresynaptic processes, are at the present time unavoidable contaminants of synaptosomal fractions. Presynaptic endings that in radioautographs contained no mitochondria were labeled. Also, presynaptic endings were labeled after incubation in the presence of chloramphenical which inhibited 20% of the protein synthesis of the synaptosomal fraction. It is concluded that besides mitochondrial protein synthesis, another protein synthesizing system operates in presynaptic endings in vitro.

Studies on the interactions of immunostimulated macrophages andYersinia enterocoliticaO:8

2000 ◽  
Vol 46 (3) ◽  
pp. 218-228 ◽  
Author(s):  
E Ivanova ◽  
I Yanchev ◽  
H Najdenski ◽  
R Toshkova ◽  
P Dimitrova ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Yersinia Enterocolitica ◽  
Peritoneal Macrophages ◽  
Microscopic Investigation ◽  
Electron Microscopic Investigation ◽  
Bacterial Cells ◽  
Electron Microscopic ◽  
Serotype O

Immunological and electron microscopy investigations of the phagocytic and killing activities of peritoneal macrophages from rats and mice against Yersinia enterocolitica serotype O:8 cells were performed. The effect of in vivo application of cytoplasmic membranes (CM) from the stable Escherichia coli WF+ L-form on macrophage activity was also studied. It was established that rat macrophages more actively phagocytosed the plasmidless pYV(-) Y. enterocolitica cells, compared to the plasmid-bearing pYV(+) Y. enterocolitica cells. The killing ability against both variants of the Y. enterocolitica strain was significantly enhanced in macrophages from CM-treated rats after 2 h, 4 h, and 24 h incubation. The CM treatment enhanced the phagocytic activity of the macrophages. The in vitro interaction of normal and immunostimulated rat macrophages with both pYV(+) and pYV(-) variants of Y. enterocolitica did not lead to any additional apoptotic and necrotic changes in macrophages compared to control macrophages, which were cultivated without Y. enterocolitica. Electron-microscopic investigation showed that mouse macrophages eliminated Y. enterocolitica pYV(+) cells in vivo after 24 h. No engulfed or digested bacterial cells were observed. Activation of cell surfaces and vacuolization of macrophage cytoplasm, both of CM-treated non-infected and infected mice, were observed. The experimental results showed that Y. enterocolitica pYV(+) cells could be eliminated by peritoneal macrophages.Key words: Yersinia enterocolitica, immunostimulation, electron microscopy, bacterial L-forms, macrophages.

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