Lomefloxacin-induced modification of the kinetics of growth of Gram-negative bacteria and susceptibility to phagocytic killing by human neutrophils

1990 ◽  
Vol 25 (1) ◽  
pp. 91-101 ◽  
Author(s):  
H. Pruul ◽  
P. J. McDonald
Keyword(s):  
Human Neutrophils ◽  
Gram Negative Bacteria ◽  
Gram Negative ◽  
Kinetics Of ◽  
Phagocytic Killing

Killing of Gram-Negative Bacteria by Ciprofloxacin within both Healthy Human Neutrophils and Neutrophils with Inactivated O2-Dependent Bactericidal Mechanisms

Chemotherapy ◽  
1999 ◽  
Vol 45 (4) ◽  
pp. 268-276 ◽  
Author(s):  
E. Cantón ◽  
J. Peman ◽  
E. Cabrera ◽  
M. Velert ◽  
A. Orero ◽  
...  
Keyword(s):  
Human Neutrophils ◽  
Gram Negative Bacteria ◽  
Healthy Human ◽  
Gram Negative

scholarly journals Bactericidal/permeability-increasing protein in the reproductive system of male mice may be involved in the sperm–oocyte fusion

Reproduction ◽  
2013 ◽  
Vol 146 (2) ◽  
pp. 135-144 ◽  
Author(s):  
Kun Li ◽  
Yue Liu ◽  
Xiaoyu Xia ◽  
Li Wang ◽  
Meige Lu ◽  
...  
Keyword(s):  
Transport Proteins ◽  
Seminal Vesicles ◽  
Lipid Transport ◽  
Human Neutrophils ◽  
Gram Negative Bacteria ◽  
Male Mice ◽  
Gram Negative ◽  
Major Function ◽  
The Family ◽  
Lps Binding

Bactericidal/permeability-increasing protein (BPI) is a 455-residue (∼55 kDa) protein found mainly in the primary (azurophilic) granules of human neutrophils. BPI is an endogenous antibiotic protein that belongs to the family of mammalian lipopolysaccharide (LPS)-binding and lipid transport proteins. Its major function is to kill Gram-negative bacteria, thereby protecting the host from infection. In addition, BPI can inhibit angiogenesis, suppress LPS-mediated platelet activation, increase DNA synthesis, and activate ERK/Akt signaling. In this study, we found thatBpiwas expressed in the testis and epididymis but not in the seminal vesicles, prostate, and solidification glands. BPI expression in the epididymis increased upon upregulation of testosterone, caused by injection of GNRH. In orchidectomized mice, BPI expression was significantly reduced, but its expression was restored to 30% of control levels in orchidectomized mice that received supplementary testosterone. The number of sperm fused per egg significantly decreased after incubation with anti-BPI antiserum. These results suggest that BPI may take part in the process of sperm–oocyte fusion and play a unique and significant role in reproduction.

scholarly journals Bifurcation kinetics of drug uptake by Gram-negative bacteria

PLoS ONE ◽  
2017 ◽  
Vol 12 (9) ◽  
pp. e0184671 ◽  
Author(s):  
David A. Westfall ◽  
Ganesh Krishnamoorthy ◽  
David Wolloscheck ◽  
Rupa Sarkar ◽  
Helen I. Zgurskaya ◽  
...  
Keyword(s):  
Drug Uptake ◽  
Gram Negative Bacteria ◽  
Gram Negative ◽  
Kinetics Of

scholarly journals THE GROWTH KINETICS OF Bacillus sp. D2.2 AT DIFFERENT pH AND SALINITY

AQUASAINS ◽  
2019 ◽  
Vol 7 (1) ◽  
pp. 647
Author(s):  
Esti Harpeni ◽  
Supono Supono ◽  
Dwi Risca Septiani
Keyword(s):  
Growth Kinetics ◽  
Generation Time ◽  
Bacterial Isolate ◽  
Gram Negative Bacteria ◽  
Bacillus Sp ◽  
Gram Negative ◽  
Gram Positive Bacteria ◽  
Kinetics Of ◽  
Growth Of Bacteria ◽  
Biocontrol Bacterium

Isolate D2.2 is a bacterial isolate with 97% homology level with Bacillus sp. This isolate is a biocontrol bacterium capable of inhibiting the growth of Gram positive bacteria and Gram negative bacteria. The use of biocontrol bacteria is one solution of disease problem in cultivation organism. Prior to being applied to the field, D2.2 isolates need to go through a series of tests, one of which is growth kinetics testing under various environmental conditions, such as different degrees of pH and salinity. This is because environmental factors can affect the rapid growth of bacteria. The purpose of this study was to study the bacterial growth kinetics of D2.2 at different pH and salinity. The growth kinetics was observed by measuring optical density (OD) through a method of turbidimetry using a spectrophotometer at a wavelength of 625 nm to the stage of death. The results showed that the fastest growth rate was found at 20 ppt salinity with 0.179 h-1 and generation time of 5,588 hours. While in all pH treatments, generation time and growth rates achieved all treatments have the same pattern.

scholarly journals Outer membrane permeabilization by the membrane attack complex sensitizes Gram-negative bacteria to antimicrobial proteins in serum and phagocytes

2021 ◽  
Vol 17 (1) ◽  
pp. e1009227
Author(s):  
Dani A. C. Heesterbeek ◽  
Remy M. Muts ◽  
Vincent P. van Hensbergen ◽  
Pieter de Saint Aulaire ◽  
Tom Wennekes ◽  
...  
Keyword(s):  
Cell Wall ◽  
Immune System ◽  
Outer Membrane ◽  
Bacterial Cell ◽  
Cell Envelope ◽  
Membrane Attack Complex ◽  
Human Neutrophils ◽  
Gram Negative Bacteria ◽  
Antimicrobial Proteins ◽  
Gram Negative

Infections with Gram-negative bacteria form an increasing risk for human health due to antibiotic resistance. Our immune system contains various antimicrobial proteins that can degrade the bacterial cell envelope. However, many of these proteins do not function on Gram-negative bacteria, because the impermeable outer membrane of these bacteria prevents such components from reaching their targets. Here we show that complement-dependent formation of Membrane Attack Complex (MAC) pores permeabilizes this barrier, allowing antimicrobial proteins to cross the outer membrane and exert their antimicrobial function. Specifically, we demonstrate that MAC-dependent outer membrane damage enables human lysozyme to degrade the cell wall of E. coli. Using flow cytometry and confocal microscopy, we show that the combination of MAC pores and lysozyme triggers effective E. coli cell wall degradation in human serum, thereby altering the bacterial cell morphology from rod-shaped to spherical. Completely assembled MAC pores are required to sensitize E. coli to the antimicrobial actions of lysozyme and other immune factors, such as Human Group IIA-secreted Phospholipase A2. Next to these effects in a serum environment, we observed that the MAC also sensitizes E. coli to more efficient degradation and killing inside human neutrophils. Altogether, this study serves as a proof of principle on how different players of the human immune system can work together to degrade the complex cell envelope of Gram-negative bacteria. This knowledge may facilitate the development of new antimicrobials that could stimulate or work synergistically with the immune system.

scholarly journals Gram-Negative Bacteria Salmonella typhimurium Boost Leukotriene Synthesis Induced by Chemoattractant fMLP to Stimulate Neutrophil Swarming

2022 ◽  
Vol 12 ◽  
Author(s):  
Ekaterina A. Golenkina ◽  
Svetlana I. Galkina ◽  
Olga Pletjushkina ◽  
Boris Chernyak ◽  
Tatjana V. Gaponova ◽  
...  
Keyword(s):  
Salmonella Typhimurium ◽  
Nuclear Membrane ◽  
Crucial Role ◽  
Bacterial Lipopolysaccharide ◽  
Human Neutrophils ◽  
Gram Negative Bacteria ◽  
Gram Negative ◽  
Reverse Sequence ◽  
Key Enzyme

Leukotriene synthesis in neutrophils is critical for host survival during infection. In particular, leukotriene B4 (LTB4) is a powerful neutrophil chemoattractant that plays a crucial role in neutrophil swarming. In this work, we demonstrated that preincubation of human neutrophils with Salmonella typhimurium strongly stimulated LTB4 production induced by the bacterial chemoattractant, peptide N-formyl-L-methionyl-L-leucyl-l-phenylalanine (fMLP), while the reverse sequence of additions was ineffective. Preincubation with bacterial lipopolysaccharide or yeast polysaccharide zymosan particles gives weaker effect on fMLP-induced LTB4 production. Activation of 5-lipoxygenase (5-LOX), a key enzyme in leukotrienes biosynthesis, depends on rise of cytosolic concentration of Ca2+ and on translocation of the enzyme to the nuclear membrane. Both processes were stimulated by S. typhimurium. With an increase in the bacteria:neutrophil ratio, the transformation of LTB4 to ω-OH-LTB4 was suppressed, which further supported increased concentration of LTB4. These data indicate that in neutrophils gathered around bacterial clusters, LTB4 production is stimulated and at the same time its transformation is suppressed, which promotes neutrophil swarming and elimination of pathogens simultaneously.

scholarly journals PHOTODYNAMIC RESPONSE IN BACTERIA

1959 ◽  
Vol 42 (5) ◽  
pp. 917-922 ◽  
Author(s):  
C. L. Baugh ◽  
J. B. Clark
Keyword(s):  
Genetic Factors ◽  
Gram Negative Bacteria ◽  
Gram Positive ◽  
Gram Negative ◽  
Photodynamic Action ◽  
X Ray ◽  
Kinetics Of

The photodynamic lethal response of Gram negative bacteria was found to be a one event phenomenon as previously reported. However, the kinetics of the lethal response in Gram-positive microorganisms was found to be more complex. The survivor response of the latter was dividable into at least two distinct parts, each of which could be influenced by various environmental and genetic factors. Some correlation was found between sensitivity or resistance to x-ray and ultraviolet radiations and sensitivity or resistance to photodynamic action.

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