Ribosome-inactivating proteins (RIPs) and their important health promoting property

RSC Advances ◽  
2016 ◽  
Vol 6 (52) ◽  
pp. 46794-46805 ◽  
Author(s):  
Shuzhen Wang ◽  
Zhiliang Li ◽  
Shiming Li ◽  
Rong Di ◽  
Chi-Tang Ho ◽  
...  

Ribosome-inactivating proteins (RIPs), widely present in plants, certain fungi and bacteria, can inhibit protein synthesis by removing one or more specific adenine residues from the large subunit of ribosomal RNAs (rRNAs).

2008 ◽  
Vol 15 (5) ◽  
pp. 737-743 ◽  
Author(s):  
Kalpana Surendranath ◽  
Anjali A. Karande

ABSTRACT Plant ribosome-inactivating proteins (RIPs) are RNA N-glycosidases that inhibit protein synthesis in cells. Abrin, a type II RIP, is an AB type toxin, which is one of the most lethal types of toxin known. The B chain facilitates the entry of the molecule into the cell, whereas the A chain exerts the toxic effect. We have generated hybridomas secreting antibodies of the immunoglobulin G class specific to the recombinant A chain of abrin. One monoclonal antibody, namely, D6F10, rescued cells from abrin toxicity. Importantly, the antibody also protected mice from lethal doses of the toxin. The neutralizing effect of the antibody was shown to be due to interference with abrin attachment to the cell surface.


1983 ◽  
Vol 216 (3) ◽  
pp. 617-625 ◽  
Author(s):  
F Stirpe ◽  
A Gasperi-Campani ◽  
L Barbieri ◽  
A Falasca ◽  
A Abbondanza ◽  
...  

Ribosome-inactivating proteins, similar to those already known [Barbieri & Stirpe (1982) Cancer Surveys 1, 489-520] were purified from the seeds of Saponaria officinalis (two proteins), of Agrostemma githago (three proteins), and of Asparagus officinalis (three proteins), and from the latex of Hura crepitans (one protein). The yield ranged from 8 to 400 mg/100 g of starting material. All proteins have an Mr of approx. 30000 and an alkaline isoelectric point. Their sugar content varies from 0 (proteins from S. officinalis) to 40% (protein from H. crepitans). The ribosome-inactivating proteins inhibit protein synthesis by rabbit reticulocyte lysate, the ID50 (concentration giving 50% inhibition) ranging from 1 ng/ml (a protein from S. officinalis) to 18 ng/ml (a protein from A. githago). Those which were tested (the proteins from S. officinalis and from A. githago) also inhibit polymerization of phenylalanine by isolated ribosomes, acting in an apparently catalytic manner. The protein from H. crepitans inhibited protein synthesis by HeLa cells, with an ID50 of 4 micrograms/ml, whereas the proteins from S. officinalis and from A. githago had an ID50 of more than 50-100 micrograms/ml. The ribosome-inactivating proteins from S. officinalis and from A. githago reduced the number of local lesions by tobacco-mosaic virus in the leaves of Nicotiana glutinosa.


1976 ◽  
Vol 81 (2) ◽  
pp. 495-506 ◽  
Author(s):  
A. Radvila ◽  
R. Roost ◽  
H. Bürgi ◽  
H. Kohler ◽  
H. Studer

ABSTRACT Lithium and excess iodide inhibit the release of thyroid hormone from preformed stores. We thus tested the hypothesis that this was due to an inhibition of thyroglobulin breakdown. Rats were pre-treated with propylthiouracil (PTU) for 3 weeks in order to deplete their thyroids of thyroglobulin. While the PTU was continued, lithium chloride (0.25 mEq./100 g weight) or potassium iodide (3 mg per rat) were injected every 12 h for 3 days. Thereafter the thyroglobulin content in thyroid gland homogenates was measured. PTU pre-treatment lowered the thyroglobulin content from 4.21 to 0.22 mg/100 mg gland. Lithium caused a marked re-accumulation of thyroglobulin to 0.60 mg/100 mg within 3 days. While iodide alone had only a borderline effect, it markedly potentiated the action of lithium and a combination of the two drugs increased the thyroglobulin content to 1.04 mg/100 mg. Thyroxine was injected into similarly pre-treated animals to suppress secretion of thyrotrophic hormone. This markedly inhibited the proteolysis of thyroglobulin and 1.3 mg/100 mg gland accumulated after 3 days. Excess iodide, given in addition to thyroxine, decreased the amount of thyroglobulin accumulated to 0.75 mg/100 mg gland. To study whether this could be explained by an inhibitory action of iodide on thyroglobulin biosynthesis, thyroid glands from animals treated with excess iodide were incubated in vitro in the presence of 0.2 mm iodide for 3 h. Iodide decreased the incorporation of radioactive leucine into total thyroidal protein and into thyroglobulin by 25 and 35 % respectively. Iodide did not inhibit protein synthesis in the kidney, liver or muscle tissue. Thus, large doses of iodide selectively inhibit thyroglobulin biosynthesis.


1975 ◽  
Vol 146 (3) ◽  
pp. 675-685 ◽  
Author(s):  
S G Siddell ◽  
R J Ellis

The function of plastid ribosomes in pea (Pisum sativum L.) was investigated by characterizing the products of protein synthesis in vitro in plastids isolated at different stages during the transition from etioplast to chloroplast. Etioplasts and plastids isolated after 24, 48 and 96h of greening in continuous white light, use added ATP to incorporate labelled amino acids into protein. Plastids isolated from greening leaves can also use light as the source of energy for protein synthesis. The labelled polypeptides synthesized in isolated plastids were analysed by electrophoresis in sodium dodecyl sulphate-ureapolyacrylamide gels. Six polypeptides are synthesized in etioplasts with ATP as energy source. Only one of these polypeptides is present in a 150 000g supernatant fraction. This polypeptide has been identified as the large subunit of Fraction I protein (3-phospho-D-glycerate carboxylyase EC 4.1.1.39) by comparing the tryptic ‘map’ of its L-(35S)methionine-labelled peptides with the tryptic ‘map’ of large subunit peptides from Fraction I labelled with L-(35S)methionine in vivo. The same gel pattern of six polypeptides is seen when plastids isolated from greening leaves are incubated with either added ATP or light as the energy source. However, the rates of synthesis of particular polypeptides are different in plastids isolated at different stages of the etioplast to chloroplast transition. The results support the idea that plastid ribosomes synthesize only a small number of proteins, and that the number and molecular weight of these proteins does not alter during the formation of chloroplasts from etioplasts.


Antioxidants ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 1016
Author(s):  
Stefania De Santis ◽  
Marina Liso ◽  
Giulio Verna ◽  
Francesca Curci ◽  
Gualtiero Milani ◽  
...  

Extra virgin olive oil (EVOO) represents one of the most important health-promoting foods whose antioxidant and anti-inflammatory activities are mainly associated to its polyphenols content. To date, studies exploring the effect of EVOO polyphenols on dendritic cells (DCs), acting as a crosstalk between the innate and the adaptive immune response, are scanty. Therefore, we studied the ability of three EVOO extracts (cv. Coratina, Cima di Mola/Coratina, and Casaliva), characterized by different polyphenols amount, to regulate DCs maturation in resting conditions or after an inflammatory stimulus. Cima di Mola/Coratina and Casaliva extracts were demonstrated to be the most effective in modulating DCs toward an anti-inflammatory profile by reduction of TNF and IL-6 secretion and CD86 expression, along with a down-modulation of Il-1β and iNOS expression. From factorial analysis results, 9 polyphenols were tentatively established to play a synergistic role in modulating DCs inflammatory ability, thus reducing the risk of chronic inflammation.


Development ◽  
1965 ◽  
Vol 13 (3) ◽  
pp. 341-356
Author(s):  
F. S. Billett ◽  
Rosalba Collini ◽  
Louie Hamilton

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.


1979 ◽  
Vol 35 (1) ◽  
pp. 253-266
Author(s):  
S.P. Gibbs

In 8 classes of algae, namely the Cryptophyceae, Raphidophyceae, Haptophyceae, Chrysophyceae, Bacillariophyceae, Xanthophyceae, Eustigmatophyceae and Phaeophyceae, the chloroplasts, in addition to being surrounded by a double-membraned chloroplast envelope, are also enclosed by a cisterna of endoplasmic reticulum called the chloroplast ER. Often this ER cisterna is continuous with the outher membrane of the nuclear envelope in such a manner that the nuclear envelope forms a part of the ER sac enclosing the chloroplast. In all these classes of algae except the Cryptophyceae, a regular network of tubules and vesicles, named the periplastidal reticulum, is present at a specific location between the chloroplast envelope and the chloroplast ER. In the Cryptophyceae, scattered vesicles are found between the chloroplast envelope and the chloroplast ER. Ribosomes which have been shown to be arranged to polysomes are found on the outer membrane of the chloroplast ER. It is proposed that nuclear-coded proteins which are destined for the chloroplast are synthesized on these polysomes, passing during synthesis into the lumen of the ER cisterna. Vesicles containing these proteins then pinch off the chloroplast ER and form the periplastidal reticulum. Vesicles containing these proteins then pinch off the chloroplast ER and form the periplastidal reticulum. Vesicles then fuse with the outer membrane of the chloroplast envelope thereby delivering their contents to the lumen of the chloroplast envelope. Proteins then cross the inner membrane of the chloroplast envelope in an as yet unknown manner. Experimental evidence for this hypothesis comes from studies on Ochromonas danica using chloramphenicol and spectinomycin, which inhibit protein synthesis on plastid ribosomes, and cycloheximide, which inhibits protein synthesis on cytoplasmic ribosomes. In cells of Ochromonas exposed to chloramphenicol or spectinomycin, the periplastidal reticulum proliferates markedly becoming several layers thick. Presumably this build up of periplastidal reticulum occurs because the transport of cytoplasmically synthesized plastid proteins is slowed down when protein synthesis in the chloroplast is inhibited. Conversely, when cells of Ochromonas are treated with cycloheximide, there is a reduction in the amount of periplastidal reticulum presumably because there are no cytoplasmically synthesized proteins to be transported into the chloroplast.


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