Localization of lectins in legume cotyledons

1975 ◽  
Vol 19 (1) ◽  
pp. 157-167
Author(s):  
A.E. Clarke ◽  
R.B. Knox ◽  
M.A. Jermyn

High-resolution techniques for the localization of lectins are described. Concanavalin A (Con A) and phytohaemagglutinin (PHA) are localized using a fluorescent method with (FITC)-labelled immunoglobulins which bind to the lectins in sections of jack and red kidney bean cotyledons. Specificity is defined by the use of specific sugar inhibitors. Both Con A and PHA are found in cytoplasmic sites. Lectins with beta-glycoside specificity are detected with red-coloured artificial carbohydrate antigens. The beta-galactosyl and beta-glucosyl antigens bind specifically to clusters of spherical bodies in the intercellular spaces, to cell wall sites, and to the periphery of the cytoplasm associated with the cell membrane.

Author(s):  
G. L. Nicolson ◽  
S. J. Singer

Plant agglutinins are proteins which bind to specific sugar ligands. For the ultrastructural localization of specific saccharides, we have now conjugated two different plant agglutinins with ferritin (Fer): concanavalin A (Con A), which binds specifically to sugars sterically related to D-glucose and D-mannose, and ricin (Ric), specific for sugars related to D-galactose and L-rhamnose.The conjugates Fer-Con A and Fer-Ric are prepared as follows. To a solution containing 8% Fer and 2.5% purified agglutinin in a buffer (SPB) containing 0.5M NaCl, 0.05M Na phosphate, pH 6.8, is added with stirring freshly distilled glutaraldehyde to a final concentration of 0.05%. Alkaline pH must be avoided to prevent aggregation of the agglutinins. After 45 min. at room temperature the mixture is dialyzed against SPB containing 0.1M NH4Cl. The Fer-agglutinins are centrifuged to remove large aggregates and finally chromatographically purified on Agarose A-1.5m (Fer-ConA) or Biogel P300 (Fer-Ric).


1976 ◽  
Vol 22 (3) ◽  
pp. 623-632
Author(s):  
G.E. Wise

The fate of concanavalin A (Con A) bound to normal and enucleated L cells was followed at the ultrastructural level over a 20-h period. In both enucleates and normal cells the Con A is seen to be distributed in a uniform manner over the entire cell surface following a 30-min pulse with a low concentration of Con A. In the subsequent chase period the cells then aggregate the Con A and Con A sites into large clusters on the cell membrane. The cells then phagocytoze the Con A and large phagocytic vacuoles containing it are observed. Thus, enucleated cells are capable of phagocytozing Con A and its sites in the same manner as normal cells.


1977 ◽  
Vol 5 (1) ◽  
pp. 91-99 ◽  
Author(s):  
J H Ellsworth ◽  
E Reiss ◽  
R L Bradley ◽  
H Chmel ◽  
D Armstrong

Yeast-form Candida albicans cells were disrupted for 1.5 min in a Braun homogenizer and centrifuged at 100,000 X g. The supernatant was concentrated by ammonium sulfate precipitation and then dialyzed. The resulting material (650 mg), containing 81.2% protein and 11.5% carbohydrate, was subjected to affinity chromatography on concanavalin A (Con A) linked to agarose. A protein fraction was eluted from the column with buffer, and a fraction containing mannan was eluted with 0.2 M alpha-methyl mannoside. The candidal soluble proteins had 19 components which were resolvable by polyacrylamide gel electrophoresis.The material with affinity for Con A contained mannan and 17% complexed protein. Antigenic differences between the soluble proteins and the mannan-protein complex were shown by lines of intersection in immunodiffusion. The soluble proteins devoid of mannan reacted in immunoelectrophoresis with sera from infected rabbits and patients with chronic candidiasis. These same sera also reacted with a mannan-protein complex eluted from the Con A column with alpha-methyl mannoside. The comparative ability of candidal proteins and cell wall-derived mannan to elicit skin test reactions in guinea pigs sensitized by infection or with formaldehyde-killed yeast was studied. Candidal proteins at a 10-mug dose elicited positive reactions at 6 and 21 days after sensitization. The reactions persisted for 48 h and showed minimal tendency to an arthus response, which was marked when mannan-containing antigens were used. The antigenicity of cell wall-derived mannans and candidal soluble proteins devoid of mannan was compared in immunodiffusion tests of sera from 39 patients with neoplastic disease. Of these patients with documented candidiasis, 13 of 20 reacted to one or more mannan antigens, and 3 of 20 reacted to candidal soluble proteins. In contrast, of those patients who were uninfected or had superficial Candida spp. infections, 5 of 19 reacted to candidal soluble proteins, and 16 of 19 reacted to one or more mannan antigens.


1975 ◽  
Vol 33 (02) ◽  
pp. 354-360 ◽  
Author(s):  
Heinrich Patscheke ◽  
Reinhard Brossmer

SummaryConcanavalin A (CON A) causes platelets to aggregate. A Ca++-independent effect of CON A could be separated from a main effect which depends on Ca++. The main effect probably is a consequence of the CON A-induced platelet release reaction and therefore is platelet-specific. The weak residual effect observed in the presence of Na2EDTA may be due to a similar mechanism as has been demonstrated for CON A-induced aggregations of several other normal and malignant transformed animal cells.Na2EDTA did not inhibit the carbohydrate-specific binding capacity of CON A. Therefore, Na2EDTA appears not to demineralize the CON A molecules under these experimental conditions.α-methyl-D-glucoside inhibits the Ca++-independent as well as the Ca++-dependent effect of CON A.Pretreatment by neuraminidase stimulated the platelet aggregation induced by CON A. It is possible that removal of terminal sialic acid residues makes additional receptors accessible for the binding of CON A.


Crop Science ◽  
1991 ◽  
Vol 31 (6) ◽  
pp. 1709-1709
Author(s):  
J. R. Myers ◽  
R. E. Hayes ◽  
J. J. Kolar
Keyword(s):  

Author(s):  
Anna Biernasiuk ◽  
Anna Berecka-Rycerz ◽  
Anna Gumieniczek ◽  
Maria Malm ◽  
Krzysztof Z. Łączkowski ◽  
...  

Abstract Recently, the occurrence of candidiasis has increased dramatically, especially in immunocompromised patients. Additionally, their treatment is often ineffective due to the resistance of yeasts to antimycotics. Therefore, there is a need to search for new antifungals. A series of nine newly synthesized thiazole derivatives containing the cyclopropane system, showing promising activity against Candida spp., has been further investigated. We decided to verify their antifungal activity towards clinical Candida albicans isolated from the oral cavity of patients with hematological malignancies and investigate the mode of action on fungal cell, the effect of combination with the selected antimycotics, toxicity to erythrocytes, and lipophilicity. These studies were performed by the broth microdilution method, test with sorbitol and ergosterol, checkerboard technique, erythrocyte lysis assay, and reversed phase thin-layer chromatography, respectively. All derivatives showed very strong activity (similar and even higher than nystatin) against all C. albicans isolates with minimal inhibitory concentration (MIC) = 0.008–7.81 µg/mL Their mechanism of action may be related to action within the fungal cell wall structure and/or within the cell membrane. The interactions between the derivatives and the selected antimycotics (nystatin, chlorhexidine, and thymol) showed additive effect only in the case of combination some of them and thymol. The erythrocyte lysis assay confirmed the low cytotoxicity of these compounds as compared to nystatin. The high lipophilicity of the derivatives was related with their high antifungal activity. The present studies confirm that the studied thiazole derivatives containing the cyclopropane system appear to be a very promising group of compounds in treatment of infections caused by C. albicans. However, this requires further studies in vivo. Key points • The newly thiazoles showed high antifungal activity and some of them — additive effect in combination with thymol. • Their mode of action may be related with the influence on the structure of the fungal cell wall and/or the cell membrane. • The low cytotoxicity against erythrocytes and high lipophilicity of these derivatives are their additional good properties. Graphical abstract


Antibiotics ◽  
2021 ◽  
Vol 10 (5) ◽  
pp. 543
Author(s):  
Ozioma F. Nwabor ◽  
Sukanlaya Leejae ◽  
Supayang P. Voravuthikunchai

As the burden of antibacterial resistance worsens and treatment options become narrower, rhodomyrtone—a novel natural antibiotic agent with a new antibacterial mechanism—could replace existing antibiotics for the treatment of infections caused by multi-drug resistant Gram-positive bacteria. In this study, rhodomyrtone was detected within the cell by means of an easy an inexpensive method. The antibacterial effects of rhodomyrtone were investigated on epidemic methicillin-resistant Staphylococcus aureus. Thin-layer chromatography demonstrated the entrapment and accumulation of rhodomyrtone within the bacterial cell wall and cell membrane. The incorporation of radiolabelled precursors revealed that rhodomyrtone inhibited the synthesis of macromolecules including DNA, RNA, proteins, the cell wall, and lipids. Following the treatment with rhodomyrtone at MIC (0.5–1 µg/mL), the synthesis of all macromolecules was significantly inhibited (p ≤ 0.05) after 4 h. Inhibition of macromolecule synthesis was demonstrated after 30 min at a higher concentration of rhodomyrtone (4× MIC), comparable to standard inhibitor compounds. In contrast, rhodomyrtone did not affect lipase activity in staphylococci—both epidemic methicillin-resistant S. aureus and S. aureus ATCC 29213. Interfering with the synthesis of multiple macromolecules is thought to be one of the antibacterial mechanisms of rhodomyrtone.


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