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Results for “Blood Bactericidal Activity”

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At least 73 records · Page 4Linked to original sources
PubMed1988

Effects of the bactericidal/permeability-increasing protein of polymorphonuclear leukocytes on isolated bacterial cytoplasmic membrane vesicles.

The bactericidal/permeability-increasing protein (BPI) of polymorphonuclear leukocytes is a potent bactericidal agent specific for gram-negative bacteria. The protein blocks bacterial multiplication without substantially inhibiting the uptake and incorporation of macromolecular precursors, suggesting that the cytoplasmic membrane escapes early injury. Because greater than 90% of bound BPI can be removed from the bacterial surface sites after irreversible loss of viability, it was uncertain whether BPI reaches the cytoplasmic membrane and, if so, affects its functions. This study shows that BPI caused similar dose-dependent inhibition of O2 consumption and metabolic energy-dependent amino acid transport by cytoplasmic membrane vesicles of both gram-negative (Escherichia coli) and gram-positive (Bacillus subtilis) bacteria. Near maximal inhibition occurred at BPI doses that caused complete killing of an equivalent number of intact E. coli, with binding of BPI to membrane vesicles that was less than or equal to 10% of binding to intact (BPI-sensitive) bacteria. The effects of BPI and of the membrane-disruptive peptide antibiotic polymyxin B on membrane vesicles were distinctly different, indicating that the two agents affect membrane function by different mechanisms. BPI also rapidly inhibited O2 consumption by intact E. coli, with minimal impairment of bacterial protein synthesis. Thus, BPI is capable of damaging the cytoplasmic membrane of both gram-negative and gram-positive bacteria and of inhibiting at least one cytoplasmic membrane-associated function in intact E. coli. The relationship between these effects and the mechanism of bacterial killing by BPI remains to be established.

Amino Acids↗
PubMed1976

Mechanisms for the microbicidal activity of cationic proteins of human granulocytes.

One oxygen-independent antimicrobial system of human granulocytes consists of granular chymotropsin-like cationic proteins possessing heat-stable microbicidal activity. For elucidation of the mode of action of the cationic protein, effects on bacterial synthesis of macromolecules, ion transport, and oxygen consumption have been studied. Inhibition of incorporation of radioactive precursors into protein, ribonulceic acid, and deoxyribonucleic acid of both Staphylococcus aureus and Escherichia coli was found concomitantly with inhibition of colony formation. Cationic protein inhibited 86Rb+ influx but did not increase the leakage of intracellular 86Rb+, indicating inhibition of energy-dependent membrane transport without a breakdown of the semipermeable character of the membrane. Oxygen consumption was inhibited. Mg2+ and Ca2+ displayed a protective effect against the microbicidal activity, indicating the operation of charge interactions between cationic protein and bacterial surface. The various effects of cationic protein were more pronounced with S. aureus than with E. coli, parallelling the microbicidal activity.

Blood Bactericidal Activity↗
PubMed1985

A one-plate assay for macrophage bactericidal activity.

Human peripheral blood monocytes purified by counterflow centrifugal elutriation (CCE) showed an enhanced capacity to kill Listeria Monocytogenes and Staphylococcus aureus after activation with interferon-gamma (IFN gamma). Bactericidal activity was evaluated by a rapid colorimetric microassay based on the reduction of a tetrazolium dye, MTT. The amount of dye reduced was directly proportional to the number of viable bacteria present in each microwell. Comparison with a bacterial titration plate containing serial dilutions from stock of a known titer allowed calculation of bacterial numbers before and after exposure to macrophages. Results were read in a multiscan plate reader and compared closely with those obtained by serial dilution on agar plates (i.e., colony counts). The entire assay, i.e., culturing the monocytes, treatment with IFN gamma, addition of the bacteria, and quantitation of surviving viable bacteria, was performed in a single microtiter plate.

Blood Bactericidal Activity↗
PubMed1973

Granulocyte-macrophage precursor cell and colony-stimulating factor responses of mice infected with Salmonella typhimurium.

The response of granulocyte-macrophage progenitor cells (in vitro colony-forming cells) and of colony-stimulating (CS) factor in serum were studied in mice infected intraperitoneally with 10(3) viable Salmonella typhimurium. Increases in the number of colony-forming cells in marrow and spleen and increases in the serum level of CS factor occurred during the infection. There was no evidence to suggest that progressive infection was associated with failure of macrophage production. Medium rich in CS factor increased the bactericidal activity of macrophages in vitro and it was suggested that CS factor could be involved in macrophage activation.

Animals↗
PubMedDate not supplied

[Activity of bactericidal peripheral granulocytes in blood of workers employed in production of ferromanganese alloys].

We estimated bactericidal activity of peripheral blood neutrophils, using nitrotetrazolium blue reduction test (NBT), in metallurgists producing ferromanganese alloys. We didn't find essential changes in neutrophils metabolic activity in metallurgists comparing with the control group. Only spontaneous reduction index mean values were lower in metallurgists working over 10 years, and higher in metallurgists who smoked more cigarettes. Chronic bronchitis increased the index of stimulated reduction NBT.

Adult↗
PubMed2001

Properties of Yersinia enterocolitica and Yersinia pseudotuberculosis in red blood cell concentrate of different ABO groups during 30-day storage at 4 degrees C.

OBJECTIVE: The present study aimed to investigate the psychrophilic properties of Yersinia enterocolitica and Yersinia pseudotuberculosis as contaminants of donated blood. METHODS: Bags with red blood cell concentrates (RBCCs) of A, B, and AB blood groups were inoculated with a bacterial suspension of Y. enterocolitica (0 : 3 and 0 : 8) and Y. pseudotuberculosis (serovars I and III) and stored at 4 degrees C for 30 days. Bacterial growth was measured at selected intervals after inoculation. Initial strains and their subcultures (isolated after 30 days' incubation at 4 degrees C) were tested for glycolytic activity and susceptibility to the bactericidal action of human serum. RESULTS: It was found that all strains grew well in the RBCCs of A, B, and AB groups. After incubation at 4 degrees C they increased their glycolytic activity and became more sensitive to the killing ability of human serum. CONCLUSIONS: The prolonged storage of contaminated Y. enterocolitica and Y. pseudotuberculosis RBCCs at 4 degrees C induces bacterial multiplication to high levels and stimulates glycolytic activity of bacterial cells.

ABO Blood-Group System↗
PubMed1989

Bacterial capacity of blood platelets in patients suffering from pneumonia.

The percent of bacteria engulfed by blood platelets, surviving in them and killed was determined in these cells taken from 22 patients with pneumonia before the treatment and from 14 patients after the treatment. The mean percent of bacteria phagocytosed by platelets collected before the treatment was 6.28 and by those after the treatment 5.01, being considerably higher than in the control group (3.42). The mean percent of bacteria surviving in platelets taken before the treatment equalled 3.10 and after the treatment 2.36 being also higher than in the control group (1.32). The mean percent of bacteria killed by platelets taken before the treatment was 3.18 and by those taken after the treatment 2.65, being also higher than in the control group. These results seem to indicate that in cases of pneumonia the blood platelets are involved into the antibacterial activity.

Blood Bactericidal Activity↗
PubMed1992

Human neutrophil azurocidin synergizes with leukocyte elastase and cathepsin G in the killing of Capnocytophaga sputigena.

Azurocidin was purified in the presence of phenylmethylsulfonyl fluoride. Electrophoresis revealed at least seven species which exhibited N-terminal sequences consistent with azurocidin. Azurocidin exhibited no bactericidal activity against Capnocytophaga sputigena or other oral bacteria but synergized the bactericidal activity of enzymatically active elastase. Azurocidin also interacted synergistically with cathepsin G.

Amino Acid Sequence↗
PubMed1983

Antibacterial activity of bovine blood neutrophils and their cationic proteins.

Six cationic protein bands were identified in extracts of both normal bovine blood neutrophils and their granules subjected to polyacrylamide disc gel electrophoresis. Band 1, the most cationic protein, was as positively charged as crystalline egg white lysozyme, and band 2 was as positively charged as ribonuclease. Antibacterial activity of various leukocyte fractions and cationic proteins was determined in vitro for Enterobacter aerogenes strain 2412-2. Antibacterial activity of various preparations was proportional to amount of test material present and varied inversely with number of bacteria in the test system. Comparative evaluations revealed that the neutrophil granule fraction had greater antibacterial activity than the whole cell homogenate or individual cationic proteins. Among cationic proteins, band 1 had the highest antibacterial activity, band 2 had the lowest, and band 3 had intermediate antibacterial activity. Cationic protein bands 4, 5, and 6 exhibited growth stimulatory rather than a growth inhibitory activity.

Animals↗
PubMed1986

Bactericidal-activities of human polymorphonuclear leukocyte proteins against Escherichia coli O111:B4 coated with C5 or C8.

The postnuclear supernatant of disrupted polymorphonuclear leukocytes exhibited bactericidal activity on Escherichia coli O111:B4 coated with immunoglobulin M antibodies and C5 or C8 but not on C3- or C7-coated bacteria. To characterize this antimicrobial activity further, granules obtained from the postnuclear supernatant were extracted with sodium acetate (pH 4) and the soluble extract was subsequently fractionated through carboxymethyl cellulose and Sephacryl S-200. Over 90% of the activity present in the starting material was recovered in the soluble granule extract. Kinetic and dose-response analyses of the bacterial activity of the polymorphonuclear leukocyte extract on BAC1-5 and BAC1-8 revealed different susceptibilities to killing of these two bacterial intermediates; they also differed for their susceptibilities to killing at 37 degrees C and at room temperature. The suggestion raised by these data, that BAC1-5 and BAC1-8 could be killed by different bactericidal factors, was confirmed by the findings that separate fractions of the soluble granule extract obtained by carboxymethyl cellulose and Sephacryl S-200 chromatography exhibited specific activity on either BAC1-5 or BAC1-8, whereas other fractions were active on both intermediates.

Blood Bactericidal Activity↗