Hemolytic activities

An affinity sorbent based on WPA-PG carrying immobilized human IgG was applied to the isolation of the first component of the complement (Cl) from human serum and for its separation into subcomponents Clr, Cls and Clq by the one-step procedure [126,127]. Cl was quantitatively bound to the sorbent at 0 °C. The activities of subcomponents Clq and Clr2r2 in the unbound part of the serum were found to be 0.8% and 3.3% of the initial activities in serum. This fraction, therefore, could be used as a R1 reagent for determining the hemolytic activity of Cl. Apparently, the neighboring macromolecules of immobilized IgG resemble to some extent an immune complex, whereas Cl formation is facilitated due to the mobility of polymer chains with the attached IgG macromolecules (Cl is usually dissociated in serum by 30%). After activation of bound Cl by heating (30 °C, 40 min) the activated subcomponent Clr is eluted from the sorbent. Stepwise elution with 0.05 mol/1 EDTA at pH 7.4 or with 0.05 mol/1 EDTA + 1 mol/1 NaCl at pH 8.5 results in a selective and quantitative elution of the activated subcomponent Cls and subcomponent Clq. 

Tab. 1.3 Magainin-mimetic peptoid sequences, and antibacterial and hemolytic activities...

Certain of these peptoid antibiotics are also selective for bacterial, rather than mammalian, cells. The selectivity of these peptoids has been measured in terms of their capacity to cause hemolysis of human erythrocytes at or near their MIC (Tab. 1.3). Interestingly, the amount of hemolysis induced by these peptoids correlates well with their hydrophobicity as there is an increasing extent of hemolysis as molecular hydrophobicity increases. These results suggest that highly hydro-phobic compounds of this class are poorly selective antibiotics. The most active antibacterial peptoids, T2-15 and T3-12, have quite low hemolytic activity near their MICs. Although highly antibacterial in vitro, T3-17 is also very hemolytic at its MIC value. 

MTX exceeds any other marine toxins known in the mouse lethality (0.13 ig/kg) and is 80 times more potent than commercial saponin (Merck) in hemolytic activity. According to Terao (72), MTX induced severe pathomorphological change in the stomach, heart and lymphoid tissues in mice and rats by i.p. injection of 200... 

Stoichactis (Stichodactyla) helianthus. It has recently been shown by CM-cellulose chromatography that heliantholysin consists of four isotoxins having different N-terminal amino acid sequences (Kern and Dunn, in press). Designated I to IV in order of increasing isoelectric pH, toxins I and II had one additional amino acid at the amino terminus than did toxin III. Toxin IV had a seven residue extension at the amino terminus relative to toxin III. Toxin HI and toxin II contributed 83% and 14% of the total hemolytic activity, respectively, and toxins I and FV together about 3%. 

Animal Hemolytic Activity of metridiolysin (hemolytic units per mL)... 

Phospholipase A activity was subsequently demonstrated to be present in venom, and it too required Ca (25). DEAE-cellulose fractionation yielded four proteins, two of which were phospholipase A and hemolytic, and two of which had neither phospholipase A nor hemolytic activities. Either of the latter two proteins enhanced to various degrees the hemolytic activity of either of the two phospholipases. The findings suggest considerable analogy with synergistic mechanisms underlying the hemolytic action of the venoms of a number of snakes. 

Cytotoxic and hemolytic activity has been obtained from the sponge Pachy-matisma johnstonii 63). Debromoaplysiatoxin, which causes contact dermatitis and a pustular folliculitis in humans and severe inflammation in rabbits, is one of the most potent skin irritants known 64). 

Within 5 min after injection, the anti-aGal IgMs detected by ELISA were diminished to 20% of the initial value determined prior to the administration, and remained at low levels for more than 4 h. Most importantly, anti-aGal antibody-mediated hemolytic activity was completely eliminated. 

Kondejewski LH, Farmer SW, Wishart DS, Kay CM, Hancock REW, Hodges RS (1996) Modulation of structure and antibacterial and hemolytic activity by ring size in cyclic gramicidin S analogs. J Biol Chem 271 25261-25268... 

Various esters of gramicidin have also been prepared115 116 117. Although these compounds have reduced hemolytic activity, they also possess less antibiotic activity. 

As has been mentioned previously, gramicidin has limited utility as an antibiotic because of its hemolytic activity (Section 1.0). Various workers have utilized the hemolytic property of the antibiotic as an assay tool. The hemolytic activity of gramicidin is probably due to its ability to form ion conducting channels in the membranes of red blood cells. The loss of isotonicity causes the cells to rupture. 

Heilman and Herrell reported the first use of the hemolytic assay to the assay of gramicidin160. Mann and coworkers compared the hemolytic activity of gramicidin and tyrocidine161. They reported that the addition of serum inhibits the hemolytic activity of gramicidin. 

Wound Healing and Hemolytic Activity of Different Extracts of Arnebia benthamii... 

Keywords Arnebia Benthamii, wound healing, Hemolytic Activity. 

The membrane fusion activity is probably a function of the El protein, since the hemolytic activity of Sindbis virus can be inhibited by monoclonal antibodies specific for El (Chanas et al., 1982). Moreover, studies using cDNA molecules coding for the spike proteins have shown that if the spike protein is expressed at the cell surface, fusion between cells is induced at low pH. However, when the p62 protein is expressed alone, no fusion occurs (Kondor-Koch et al., 1983). 

Many structure—activity relationship studies of host defense peptides have also focused on LL-37. Importantly, LL-37 has a broad spectrum of activities within the immune system but has also displayed cytotoxic activities that would diminish the therapeutic application of this peptide. Thus, structure—activity studies of LL-37 have focused on this cytotoxicity. A study by Nagaoka et al has demonstrated that the cytotoxic and hemolytic activities of LL-37 may reside within different regions of the peptide. Using an 18-mer... 

Coolia monotis is another related, macro-algal associated species which also spreads into more temperate waters where it is commonly associated with Ulva. It is not very toxic, with only slight hemolytic activity found in a strain from Okinawa (51). 

On the other hand toluene (4) and 5-methoxy-indole (5) would not be considered very similar from a conventional point of view, yet their hemolytic activity is the same (logl/C = 1.93, where C is the minimal molar concentration which causes 100% hemolysis in rabbit erythrocytes l)). Obviously, topological similarity or dissimilarily is not always a factor which is relevant for biological activity. In the present example the relevant feature is a physicochemical property of the compounds, i.e. lipophilicity as expressed by the octanol/water partition coefficient... 

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