scholarly journals THE INACTIVATION OF COMPLEMENT AND ITS COMPONENTS BY PLASMIN

1953 ◽  
Vol 97 (4) ◽  
pp. 573-589 ◽  
Author(s):  
Louis Pillemer ◽  
Oscar D. Ratnoff ◽  
Livia Blum ◽  
I. H. Lepow
Keyword(s):  
Human Serum ◽  
Proteolytic Enzyme ◽  
Complement Fixation ◽  
Hydrogen Ion ◽  
Complement Components ◽  
High Hydrogen ◽  
Ion Concentrations ◽  
Plasmin Inhibitors ◽  
Antigen Antibody

Human complement is inactivated by plasmin, the proteolytic enzyme of plasma or serum active at or near neutrality. The addition of streptokinase to human serum, which converts plasminogen to plasmin, also causes the inactivation of complement components C'2 and C'4 and varying amounts of C'1. C'3 is the most resistant to inactivation by plasmin. Chloroform-activated human plasmin and bovine plasmin also destroy these components of complement, but are less effective than the streptokinase-activated enzyme. The inactivation of complement by the addition of streptokinase to human serum is inhibited by high hydrogen ion concentrations, low temperature, and elevated ionic strength. The inactivation of the components of complement in various fractions of serum is influenced by the available plasminogen and the content of plasmin inhibitors in these fractions. Certain similarities are pointed out between the components of complement and the factors in the plasmin system and between the inactivation of the components of complement by antigen-antibody reactions, by specific agents, and by plasmin. The possible significance of these relationships in immune hemolysis and complement fixation, and the possible role of the plasmin system in the instability of complement and the development of anticomplementary properties in serum are discussed.

scholarly journals THE RELATION OF PROTEOLYTIC ENZYMES IN THE PNEUMONIC LUNG TO HYDROGEN ION CONCENTRATION. AN EXPLANATION OF RESOLUTION

1919 ◽  
Vol 30 (4) ◽  
pp. 379-388 ◽  
Author(s):  
Frederick T. Lord
Keyword(s):  
Amino Acid ◽  
Proteolytic Enzyme ◽  
Gradual Increase ◽  
Cellular Material ◽  
Hydrogen Ion ◽  
Ion Concentration ◽  
Acid Media ◽  
Hydrogen Ion Concentration ◽  
Ion Concentrations ◽  
Amino Acid Nitrogen

Evidence is given of the presence in the cellular material obtained from the pneumonic lung of a proteolytic enzyme digesting coagulated blood serum at hydrogen ion concentrations of 7.3 to 6.7 and inactive at higher; i.e., more acid concentrations. In addition, evidence is brought forward of the presence in the cellular material from the pneumonic lung of a proteolytic enzyme splitting peptone to amino-acid nitrogen. This enzyme is operative at hydrogen ion concentrations from 8.0 to 4.8, but most active at 6.3 or 5.2. These findings may be regarded as having a bearing on resolution in pneumonia. During the course of the disease a gradual increase in the hydrogen ion concentration of the exudate probably takes place. With the breaking down of cellular material an enzyme digesting protein (fibrin) in weakly alkaline and weakly acid media may be liberated. With a gradual increase in the hydrogen ion concentration of the pneumonic lung the action of this enzyme probably ceases. An enzyme capable of splitting peptone to amino-acid nitrogen is probably active during the proteolysis of the fibrin and further activated when the hydrogen ion concentration of the pneumonic lung is increased to within its range of optimum activity at a pH of 6.3 and 5.2. By this means it may be conceived that the exudate is dissolved and resolution takes place.

Some Distinctive Characteristics of the Alkaline Phosphatase of Serratia marcescens

1975 ◽  
Vol 53 (7) ◽  
pp. 819-822 ◽  
Author(s):  
A. R. Bhatti
Keyword(s):  
Escherichia Coli ◽  
Alkaline Phosphatase ◽  
Serratia Marcescens ◽  
Heat Stability ◽  
Hydrogen Ion ◽  
High Hydrogen ◽  
E Coli ◽  
Ion Concentrations ◽  
Enzyme Species

A mutant strain of Serratia marcescens produces a constitutive enzyme (phosphatase F) which differs from the alkaline phosphatase of Escherichia coli in the following characteristics: one enzyme species with higher mobility on electrophoresis, less heat stability, no rapid reactivation following exposure to high hydrogen ion concentrations, no hybridization with E. coli enzyme in vitro, little activation at increased ionic strength, greater sensitivity to EDTA inhibition, and no cross reaction of rabbit anti-serum with the E. coli enzyme.

scholarly journals STUDIES ON ANTIGEN-ANTIBODY COMPLEXES

1971 ◽  
Vol 133 (4) ◽  
pp. 713-739 ◽  
Author(s):  
Mart Mannik ◽  
William P. Arend ◽  
Anthony P. Hall ◽  
Bruce C. Gilliland
Keyword(s):  
Immune Complexes ◽  
Disulfide Bonds ◽  
Complement Fixation ◽  
Solid Phase ◽  
Complement Components ◽  
Specific Antibodies ◽  
Optimal Function ◽  
Soluble Immune Complexes ◽  
Rapid Removal ◽  
Antigen Antibody

Solid phase immunoadsorbents were prepared by coupling antigens to agarose. With this technique specific antibodies were easily isolated in large amounts. The γG-globulin class of antibodies isolated in this manner were not denatured as judged by their normal biological half-life in rabbits. Soluble immune complexes at fivefold antigen excess were prepared from isolated specific antibodies and HSA, human λ-chains, human λG-globulins, and a Waldenström's macroglobulin as antigens. In all these preparations a characteristic immune complex was encountered that represented the smallest stable antigen-antibody union. In the HSA-anti-HSA system they were found to be AgAb2 complexes, and Ag2Ab complexes in the γG-anti-γG system. These stable complexes fixed complement ineffectively. Also, a spectrum of larger complexes was present in each system, and these complexes fixed complement effectively. With intact antibodies the disappearance curves of immune complexes from the circulation were composed of three exponential components. The immune complexes larger than AgAb2 were quickly removed from the circulation with half-lives of 0.09–0.37 hr. Their clearance was not dependent on complement components, in that depletion of complement by cobra venom factor and aggregated γG-globulin did not alter the pattern of their removal from the circulation. However, when the interchain disulfide bonds of antibodies were reduced and alkylated, the removal of the λ-anti-λ, HSA-anti-HSA, and γG-anti-γG complexes was altered. In these experiments the disappearance curves were composed of two exponential components and the rapid removal of the greater than AgAb2 complexes did not occur. The immune complexes prepared from reduced and alkylated antibodies fixed complement ineffectively. The presented data indicate that the rapid removal of circulating immune complexes, containing γG-globulin molecules as antibodies, depends primarily on the number of antibodies involved. Furthermore, complement fixation is not involved in the rapid removal of such complexes. Nevertheless, the rapid removal of immune complexes and their ability to fix complement have similarities for optimal function in that both processes require intact interchain disulfide bonds of antibodies and complexes that exceed the AgAb2 combination.

scholarly journals SOME PROPERTIES OF AN ESTERASE DERIVED FROM PREPARATIONS OF THE FIRST COMPONENT OF COMPLEMENT

1957 ◽  
Vol 106 (2) ◽  
pp. 327-343 ◽  
Author(s):  
Oscar D. Ratnoff ◽  
Irwin H. Lepow
Keyword(s):  
Amino Acid ◽  
Human Serum ◽  
Hydrolytic Enzymes ◽  
Physiological Role ◽  
Amino Acid Esters ◽  
Synthetic Amino Acid ◽  
Early Hypothesis ◽  
Antigen Antibody ◽  
Acid Esters

Studies on an esterase derived from partially purified preparations of the first component of complement are described. The esterase hydrolyzed certain synthetic amino acid esters, among which N-acetyl-L-tyrosine ethyl ester was most susceptible. This was hydrolyzed maximally between pH 7.5 and 8.2, and at 41°C. The esterase could not be identified with other previously described hydrolytic enzymes. An esterase with similar properties could also be eluted from antigen-antibody aggregates which had been treated with serum. Human serum contained a heat-labile inhibitor of the esterase which could not be identified with any of the known components of complement. The esterase was also inhibited by certain reducing agents. The experiments described support the early hypothesis that complement exerts its action enzymatically, but the physiological role of the esterase derived from preparations of complement is not yet clear.

scholarly journals RND Efflux Systems Contribute to Resistance and Virulence of Aliarcobacter butzleri

Antibiotics ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 823
Author(s):  
Cristiana Mateus ◽  
Ana Rita Nunes ◽  
Mónica Oleastro ◽  
Fernanda Domingues ◽  
Susana Ferreira
Keyword(s):  
Oxidative Stress ◽  
Human Serum ◽  
Ethidium Bromide ◽  
Biofilm Formation ◽  
Bacterial Resistance ◽  
Efflux Pumps ◽  
Bacterial Virulence ◽  
Relative Fitness ◽  
Mutant Strains

Aliarcobacter butzleri is an emergent enteropathogen that can be found in a range of environments. This bacterium presents a vast repertoire of efflux pumps, such as the ones belonging to the resistance nodulation cell division family, which may be associated with bacterial resistance, as well as virulence. Thus, this work aimed to evaluate the contribution of three RND efflux systems, AreABC, AreDEF and AreGHI, in the resistance and virulence of A. butzleri. Mutant strains were constructed by inactivation of the gene that encodes the inner membrane protein of these systems. The bacterial resistance profile of parental and mutant strains to several antimicrobials was assessed, as was the intracellular accumulation of the ethidium bromide dye. Regarding bacterial virulence, the role of these three efflux pumps on growth, strain fitness, motility, biofilm formation ability, survival in adverse conditions (oxidative stress and bile salts) and human serum and in vitro adhesion and invasion to Caco-2 cells was evaluated. We observed that the mutants from the three efflux pumps were more susceptible to several classes of antimicrobials than the parental strain and presented an increase in the accumulation of ethidium bromide, indicating a potential role of the efflux pumps in the extrusion of antimicrobials. The mutant strains had no bacterial growth defects; nonetheless, they presented a reduction in relative fitness. For the three mutants, an increase in the susceptibility to oxidative stress was observed, while only the mutant for AreGHI efflux pump showed a relevant role in bile stress survival. All the mutant strains showed an impairment in biofilm formation ability, were more susceptible to human serum and were less adherent to intestinal epithelial cells. Overall, the results support the contribution of the efflux pumps AreABC, AreDEF and AreGHI of A. butzleri to antimicrobial resistance, as well as to bacterial virulence.

scholarly journals The acidity of muscle during maintained contraction

1922 ◽  
Vol 93 (654) ◽  
pp. 406-410
Keyword(s):  
Manganese Dioxide ◽  
Hydrogen Ion ◽  
Ion Concentrations

In 1913, I described a method for recording changes in hydrogen-ion concentrations in tissues, by means of a manganese dioxide electrode in combination with a calomel electrode (1). By this method it was shown that the acidity of muscle probably increased at the same time as, or slightly before, the tension increased, and that the acidity decreased as the muscle relaxed (2). In a paper, which appeared as this note was being prepared for publication, Ritchie states that he has been unable to detect a variation in acidity by the use of manganese dioxide electrodes. I am inclined to think that his failure is due to the injury to the muscles on insertion of wires into its substance. In my own experiments the wires rest on the surface of the muscle.

Sign in / Sign up

Export Citation Format

Share Document