Plant protoplast agglutination and membrane-bound beta-lectins

1977 ◽  
Vol 26 (1) ◽  
pp. 31-46
Author(s):  
P.J. Larkin
Keyword(s):  
Immune Serum ◽  
Plant Protoplast ◽  
Carbohydrate Antigens ◽  
New Class ◽  
Specific Serum ◽  
Serum Component ◽  
Membrane Bound

Plant protoplast agglutination caused by normal and immune serum and by artificial carbohydrate antigens is described. Evidence is presented that the new class of lectins, called all-beta lectins by previous authors, are present in protoplast membranes and responsible for both forms of agglutination. Some non-specific serum component and the artificial antigens are the 2 respective passive ‘bridge’ molecules between agglutinating protoplasts.

scholarly journals Genetic and Phenotypic Analyses of therdx Locus of Rhodobacter sphaeroides2.4.1

2000 ◽  
Vol 182 (12) ◽  
pp. 3475-3481 ◽  
Author(s):  
Jung Hyeob Roh ◽  
Samuel Kaplan
Keyword(s):  
Gene Expression ◽  
Rhodobacter Sphaeroides ◽  
Redox Protein ◽  
Deletion Mutations ◽  
Metal Transporter ◽  
New Class ◽  
Mutant Strains ◽  
Membrane Bound ◽  
Photosynthesis Gene

ABSTRACT Previously, we reported that rdxB, encoding a likely membrane-bound two [4Fe-4S]-containing center, is involved in the aerobic regulation of photosystem gene expression in Rhodobacter sphaeroides 2.4.1. To further investigate the role ofrdxB as well as other genes of the rdxBHISoperon on photosystem gene expression, we constructed a series of nonpolar, in-frame deletion mutations in each of the rdxgenes. Using both puc and puf operonlacZ fusions to monitor photosystem gene expression, under aerobic conditions, in each of the mutant strains revealed significant increased photosynthesis gene expression. In the case of mutations in either rdxH, rdxI, or rdxS, the aerobic induction of photosystem gene expression is believed to be indirect by virtue of a posttranscriptional effect oncbb 3 cytochrome oxidase structure and integrity. For RdxB, we suggest that this redox protein has a more direct effect on photosystem gene expression by virtue of its interaction with the cbb 3 oxidase. An associated phenotype, involving the enhanced conversion of the carotenoid spheroidene to spheroidenone, is also observed in the RdxB, -H, -I, and -S mutant strains. This phenotype is also suggested to be the result of the role of the rdxBHIS locus incbb 3 oxidase activity and/or structure. RdxI is suggested to be a new class of metal transporter of the CPx-type ATPases.

scholarly journals Ceapins are a new class of unfolded protein response inhibitors, selectively targeting the ATF6α branch

eLife ◽  
2016 ◽  
Vol 5 ◽  
Author(s):  
Ciara M Gallagher ◽  
Carolina Garri ◽  
Erica L Cain ◽  
Kenny Kean-Hooi Ang ◽  
Christopher G Wilson ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Er Stress ◽  
Unfolded Protein Response ◽  
Proteolytic Processing ◽  
Unfolded Protein ◽  
New Class ◽  
Cancer Models ◽  
Membrane Bound ◽  
The Unfolded Protein Response ◽  
Protein Response

The membrane-bound transcription factor ATF6α plays a cytoprotective role in the unfolded protein response (UPR), required for cells to survive ER stress. Activation of ATF6α promotes cell survival in cancer models. We used cell-based screens to discover and develop Ceapins, a class of pyrazole amides, that block ATF6α signaling in response to ER stress. Ceapins sensitize cells to ER stress without impacting viability of unstressed cells. Ceapins are highly specific inhibitors of ATF6α signaling, not affecting signaling through the other branches of the UPR, or proteolytic processing of its close homolog ATF6β or SREBP (a cholesterol-regulated transcription factor), both activated by the same proteases. Ceapins are first-in-class inhibitors that can be used to explore both the mechanism of activation of ATF6α and its role in pathological settings. The discovery of Ceapins now enables pharmacological modulation all three UPR branches either singly or in combination.

scholarly journals THE CONCENTRATION OF THE PROTECTIVE BODIES IN ANTIPNEUMOCOCCUS SERUM. SPECIFIC PRECIPITATE EXTRACTS

1915 ◽  
Vol 22 (2) ◽  
pp. 248-268 ◽  
Author(s):  
Henry T. Chickering
Keyword(s):  
Sodium Carbonate ◽  
Immune Serum ◽  
Passive Immunity ◽  
Type I ◽  
Type Ii ◽  
Extractive Agent ◽  
Bacterial Extract ◽  
Specific Serum ◽  
Active Immunity ◽  
Successive Addition

1. The protective substances contained in specific precipitates from antipneumococcus serum can be extracted by suitable chemical and physical agents, dilute sodium carbonate at 42°C. being especially advantageous as an extractive agent. 2. The resulting water-clear extracts, when made up to the original volume of the serum used for precipitation, protect animals almost as well as does the whole serum. 3. The bacterial extracts used in precipitating the protective substances from the serum act specifically; that is, a bacterial extract of pneumococcus of Type I removes the protective substances from a Type I immune serum only. 4. In a polyvalent serum of Type I and Type II, the protective substances of each type may be removed independently of each other by the successive addition of the homologous antigens. 5. Extracts of specific serum precipitates contain only one-fiftieth to one-sixtieth of the protein in the original serum, and about one-half the protein of the whole precipitate. 6. Extracts contain not only protective substances but agglutinins and precipitins. 7. Extracts and whole precipitates not only confer passive immunity but stimulate the production of active immunity to pneumococcus infection in rabbits and mice.

scholarly journals Controlling compartmentalization by non-membrane-bound organelles

2018 ◽  
Vol 373 (1747) ◽  
pp. 20170193 ◽  
Author(s):  
Richard J. Wheeler ◽  
Anthony A. Hyman
Keyword(s):  
Phase Separation ◽  
Cell Biology ◽  
Scaffold Protein ◽  
Theme Issue ◽  
New Class ◽  
Cellular Events ◽  
Condensate Formation ◽  
Membrane Bound ◽  
Two Phases ◽  
In Cells

Compartmentalization is a characterizing feature of complexity in cells, used to organize their biochemistry. Membrane-bound organelles are most widely known, but non-membrane-bound liquid organelles also exist. These have recently been shown to form by phase separation of specific types of proteins known as scaffolds. This forms two phases: a condensate that is enriched in scaffold protein separated by a phase boundary from the cytoplasm or nucleoplasm with a low concentration of the scaffold protein. Phase separation is well known for synthetic polymers, but also appears important in cells. Here, we review the properties of proteins important for forming these non-membrane-bound organelles, focusing on the energetically favourable interactions that drive condensation. On this basis we make qualitative predictions about how cells may control compartmentalization by condensates; the partition of specific molecules to a condensate; the control of condensation and dissolution of condensates; and the regulation of condensate nucleation. There are emerging data supporting many of these predictions, although future results may prove incorrect. It appears that many molecules may have the ability to modulate condensate formation, making condensates a potential target for future therapeutics. The emerging properties of condensates are fundamentally unlike the properties of membrane-bound organelles. They have the capacity to rapidly integrate cellular events and act as a new class of sensors for internal and external environments. This article is part of the theme issue ‘Self-organization in cell biology’.

scholarly journals THE PNEUMOCOCCAL CAPSULAR SWELLING REACTION, STUDIED WITH THE AID OF THE ELECTRON MICROSCOPE

1943 ◽  
Vol 78 (5) ◽  
pp. 327-332 ◽  
Author(s):  
Stuart Mudd ◽  
Ferdinand Heinmets ◽  
Thomas F. Anderson
Keyword(s):  
Capsular Polysaccharide ◽  
Specific Antigen ◽  
Immune Serum ◽  
Rabbit Serum ◽  
Surface Deposit ◽  
Specific Serum ◽  
Antibody Complex ◽  
Wall Interaction ◽  
Antigen Antibody ◽  
Serum Components

Electron micrographs indicate, in harmony with previous findings, that the pneumococcal capsule is a gel of low density outside of and closely applied to the bacterial cell wall. Interaction with homologous immune rabbit serum greatly increases the thickness and density of this capsular gel; the increase in thickness of the specifically swollen pneumococcal capsule may exceed by 25-fold the thickness of the surface deposit caused by rabbit immune serum on the cell walls and flagella of homologous non-capsulated bacteria. Conclusions drawn from these and earlier data are that homologous immune serum permeates the pneumococcal capsular gel; the specific antibody combines with the capsular polysaccharide; non-specific serum components are secondarily adsorbed to or combined with the specific antigen-antibody complex. The relatively low antibacterial titers characteristic of pneumococcal antisera can be explained in part by the permeation of the capsule by antiserum, in part by the high combining capacity of pneumococcal carbohydrate for antibody (17).

scholarly journals Synthesis of Pyrazolo[1,2-b]phthalazine-5,10- dione Derivatives: A New Class of α –Glucosidase Inhibitors

2021 ◽  
Author(s):  
Maryam Hosseinpoor Tehrani ◽  
Seyed Ahmad Mirshokraie ◽  
Mehdi Khoobi ◽  
Mohsen Amini
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Enzyme Activity ◽  
Biological Activity ◽  
Inhibitory Activity ◽  
Diabetic Patients ◽  
New Class ◽  
Glucosidase Inhibitors ◽  
Membrane Bound ◽  
Carbohydrate Digestion ◽  
Control Post

Background: Hyperglycemia is a metabolic disorder that refers to an increase in blood sugar in diabetic patients. α-Glucosidase has been introduced as a membrane-bound enzyme, and it is the main enzyme for carbohydrate digestion in some parts of the intestine. Inhibition of α -glucosidase enzyme activity is a reliable approach to control post-prandial hyperglycemia condition. Objectives: In this study, a series of Pyrazolo[1,2-b]phthalazine-5,10-dione derivatives 5a–t were synthesized via a multicomponent reaction and evaluated as new inhibitors for α-glucosidase. Methods: The biological activity of the synthesized compounds was studied using a source of the α-glucosidase enzyme (EC3.2.1.20, Saccharomyces cerevisiae) at 20 U/mg concentration. Results: Four compounds showed higher α-glucosidase inhibitory activity in comparison to a standard, i.e., Acarbose. Compound 5q displays the most potent α-glucosidase inhibitory activity (IC50 = 155.4 ± 6.0 μM). Conclusion: In conclusion, some of the synthesized compounds, including heterocyclic core molecules, have shown remarkable activity that could be considered as subjects for the development of new, more efficient inhibitors of the α-glucosidase enzyme.

scholarly journals THE PRODUCTION OF ANTIPNEUMOCOCCIC SERUM

1917 ◽  
Vol 26 (4) ◽  
pp. 537-561 ◽  
Author(s):  
Rufus Cole ◽  
Henry F. Moore
Keyword(s):  
Immune Serum ◽  
Type I ◽  
High Grade ◽  
Specific Serum ◽  
Therapeutic Value ◽  
Immunological Specificity ◽  
Small Doses ◽  
Living Organisms

In the production of immune serum for therapeutic purposes strict attention must be paid to the immunological specificity of the bacteria used for immunization. At present the only serum of which the therapeutic value has been proven is that effective against Type I pneumococcus infection. This serum should have agglutinating power for Type I pneumococcus and should have the power of protecting mice against large amounts of virulent culture. Experiments have shown that for producing the primary immunity most rapidly several series of small doses of dead cultures should be given, the injections being made daily for 6 to 7 days, followed by a week in which no injections are made. To produce the highest type of immunity probably living organisms are required. These should be given in moderate doses daily for 3 days, with an interval of a week between each series of injections. By following accurately the methods described, horses may be made to produce rapidly a high grade of specific serum. The observations so far made indicate the importance of employing small doses of culture frequently repeated in this form of immunization.

Delineating a New Class of Membrane-Bound Guanylate Cyclases

2016 ◽  
Vol 4 (1) ◽  
pp. 1-13 ◽  
Author(s):  
Victor Muleya ◽  
Helen R. Irving
Keyword(s):  
New Class ◽  
Membrane Bound

scholarly journals Non-detergent sulphobetaines: a new class of mild solubilization agents for protein purification

1995 ◽  
Vol 305 (1) ◽  
pp. 337-343 ◽  
Author(s):  
L Vuillard ◽  
C Braun-Breton ◽  
T Rabilloud
Keyword(s):  
Alkaline Phosphatase ◽  
Plasmodium Falciparum ◽  
Protein Purification ◽  
Isoelectric Focusing ◽  
Nuclear Proteins ◽  
New Class ◽  
Erythrocyte Invasion ◽  
Membrane Bound ◽  
Beta Galactosidase ◽  
Mild Solubilization

The action of non-detergent sulphobetaines (NDSBs) as new mild agents for protein purification is described. The solubilization effects of non-detergent sulphobetaines are shown in different examples; all obtained under non-denaturing conditions: (1) microsomal proteins extraction; (2) recovery after dialysis of nuclear proteins; (3) reduction of precipitation in isoelectric focusing experiments under non-denaturing conditions; and (4) purification of a membrane-bound serine protease from Plasmodium falciparum involved in erythrocyte invasion by malaria merozoites. The absence of a significant denaturation effect induced by NDSBs is demonstrated by tests on beta-galactosidase and alkaline phosphatase. A simple NDSB synthesis and some possible explanations of the action of NDSBs are also presented.

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