Bactericidal Effect of Lactoferrin and Its Amidated and Pepsin-Digested Derivatives on Pseudomonasfluorescens: Influence of Environmental and Physiological Factors

2008 ◽  
Vol 71 (12) ◽  
pp. 2468-2474 ◽  
Author(s):  
ANA del OLMO ◽  
PILAR MORALES ◽  
MANUEL NUÑEZ
Keyword(s):  
Complex Systems ◽  
Bactericidal Activity ◽  
Phosphate Buffer ◽  
Bactericidal Effect ◽  
Bovine Lactoferrin ◽  
Medium Ph ◽  
Physiological Factors ◽  
Pepsin Digestion ◽  
Neutral Ph ◽  
Bacterial Inoculum

The influence of environmental and physiological factors such as substrate composition and inoculum characteristics on the bactericidal activity of bovine lactoferrin (LF) and its amidated and pepsin-digested derivatives against Pseudomonasfluorescens was investigated. Amidated LF (AMILF) exerted the most potent bactericidal activity, with a 5.8-log decrease in P.fluorescens counts, and LF the lowest, with just a 1-log decrease, whereas pepsin-digested LF (PDLF) reduced bacterial counts by 2.7 log, after 1 h at 30°C. Amidation of PDLF increased effectiveness by 1.2 log, whereas pepsin digestion of AMILF decreased effectiveness by 2.8 log. Bactericidal activity of LF and its derivatives was higher in Tris buffer than in phosphate buffer. The bactericidal effect of AMILF and PDLF was enhanced as medium pH was increased from 5.5 to 8.5, whereas LF showed higher activity under acidic or basic conditions than at neutral pH. The presence of cations affected the activity of LF and its derivatives, from a concentration of 10 mM for K+, 1 mM for Na+, and 0.1 mM for Ca2+,Co2+,Cu2+, Mg2+,Zn2+, and Fe3+. Bactericidal effectiveness diminished as the bacterial inoculum was increased. Log-phase cultures (10-h incubation) were less sensitive to the bactericidal activity of LF and its derivatives than stationary cultures (20- and 30-h incubation). All these factors should be considered when applications of LF and its derivatives in foods and other complex systems are investigated.

Examination of Rabbit Fc Crystals

1968 ◽  
Vol 26 ◽  
pp. 140-141
Author(s):  
J. P. Robinson ◽  
P. G. Lenhert
Keyword(s):  
Molecular Weight ◽  
Flat Plate ◽  
Phosphate Buffer ◽  
Asymmetric Unit ◽  
X Ray Diffraction ◽  
X Ray ◽  
Neutral Ph ◽  
Small Crystals ◽  
Carbon Coated ◽  
Diffraction Patterns

Crystallographic studies of rabbit Fc using X-ray diffraction patterns were recently reported. The unit cell constants were reported to be a = 69. 2 A°, b = 73. 1 A°, c = 60. 6 A°, B = 104° 30', space group P21, monoclinic, volume of asymmetric unit V = 148, 000 A°3. The molecular weight of the fragment was determined to be 55, 000 ± 2000 which is in agreement with earlier determinations by other methods.Fc crystals were formed in water or dilute phosphate buffer at neutral pH. The resulting crystal was a flat plate as previously described. Preparations of small crystals were negatively stained by mixing the suspension with equal volumes of 2% silicotungstate at neutral pH. A drop of the mixture was placed on a carbon coated grid and allowed to stand for a few minutes. The excess liquid was removed and the grid was immediately put in the microscope.

scholarly journals A Fish Galectin-8 Possesses Direct Bactericidal Activity

2020 ◽  
Vol 22 (1) ◽  
pp. 376
Author(s):  
Tengfei Zhang ◽  
Shuai Jiang ◽  
Li Sun
Keyword(s):  
Bactericidal Activity ◽  
Bacterial Pathogens ◽  
Bactericidal Effect ◽  
Immune Defense ◽  
Carbohydrate Binding ◽  
Dependent Manner ◽  
Animal Cells ◽  
Gram Negative ◽  
Tongue Sole ◽  
Wide Range

Galectins are a family of animal lectins with high affinity for β-galactosides. Galectins are able to bind to bacteria, and a few mammalian galectins are known to kill the bound bacteria. In fish, no galectins with direct bactericidal effect have been reported. In the present study, we identified and characterized a tandem repeat galectin-8 from tongue sole Cynoglossus semilaevis (designated CsGal-8). CsGal-8 possesses conserved carbohydrate recognition domains (CRDs), as well as the conserved HXNPR and WGXEE motifs that are critical for carbohydrate binding. CsGal-8 was constitutively expressed in nine tissues of tongue sole and up-regulated in kidney, spleen, and blood by bacterial challenge. When expressed in HeLa cells, CsGal-8 protein was detected both in the cytoplasm and in the micro-vesicles secreted from the cells. Recombinant CsGal-8 (rCsGal-8) bound to lactose and other carbohydrates in a dose dependent manner. rCsGal-8 bound to a wide range of gram-positive and gram-negative bacteria and was co-localized with the bound bacteria in animal cells. Lactose, fructose, galactose, and trehalose effectively blocked the interactions between rCsGal-8 and different bacteria. Furthermore, rCsGal-8 exerted potent bactericidal activity against some gram-negative bacterial pathogens by directly damaging the membrane and structure of the pathogens. Taken together, these results indicate that CsGal-8 likely plays an important role in the immune defense against some bacterial pathogens by direct bacterial interaction and killing.

scholarly journals Hyperbaric Oxygen Sensitizes Anoxic Pseudomonas aeruginosa Biofilm to Ciprofloxacin

2017 ◽  
Vol 61 (11) ◽  
Author(s):  
Mette Kolpen ◽  
Christian J. Lerche ◽  
Kasper N. Kragh ◽  
Thomas Sams ◽  
Klaus Koren ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Hyperbaric Oxygen ◽  
Bactericidal Activity ◽  
Host Response ◽  
Polymorphonuclear Leukocytes ◽  
Bactericidal Effect ◽  
Aerobic Respiration ◽  
Hyperbaric Oxygen Treatment ◽  
Content Type ◽  
Oxygen Treatment

ABSTRACT Chronic Pseudomonas aeruginosa lung infection is characterized by the presence of endobronchial antibiotic-tolerant biofilm, which is subject to strong oxygen (O2) depletion due to the activity of surrounding polymorphonuclear leukocytes. The exact mechanisms affecting the antibiotic susceptibility of biofilms remain unclear, but accumulating evidence suggests that the efficacy of several bactericidal antibiotics is enhanced by stimulation of aerobic respiration of pathogens, while lack of O2 increases their tolerance. In fact, the bactericidal effect of several antibiotics depends on active aerobic metabolism activity and the endogenous formation of reactive O2 radicals (ROS). In this study, we aimed to apply hyperbaric oxygen treatment (HBOT) to sensitize anoxic P. aeruginosa agarose biofilms established to mimic situations with intense O2 consumption by the host response in the cystic fibrosis (CF) lung. Application of HBOT resulted in enhanced bactericidal activity of ciprofloxacin at clinically relevant durations and was accompanied by indications of restored aerobic respiration, involvement of endogenous lethal oxidative stress, and increased bacterial growth. The findings highlight that oxygenation by HBOT improves the bactericidal activity of ciprofloxacin on P. aeruginosa biofilm and suggest that bacterial biofilms are sensitized to antibiotics by supplying hyperbaric O2.

scholarly journals Catalysis of Hydrazone and Oxime Peptide Ligation by Arginine

2020 ◽  
Author(s):  
Nathalie Ollivier ◽  
Vangelis Agouridas ◽  
Benoît Snella ◽  
Rémi Desmet ◽  
Hervé Drobecq ◽  
...  
Keyword(s):  
Protein Aggregation ◽  
Phosphate Buffer ◽  
Side Chain ◽  
Neutral Ph ◽  
Arginine Hydrochloride ◽  
Guanidinium Group ◽  
Aggregation Inhibitor ◽  
Peptide Ligation

Hydrazone and oxime peptide ligations are catalyzed by arginine. The catalysis is assisted intramolecularly by the side-chain guanidinium group. Hydrazone ligation in the presence of arginine proceeds efficiently in phosphate buffer at neutral pH but is particularly powerful in bicarbonate/CO<sub>2</sub> buffer. In addition to acting as a catalyst, arginine prevents the aggregation of proteins during ligation. With its dual properties as nucleophilic catalyst and protein aggregation inhibitor, arginine hydrochloride is a useful addition to the hydrazone/oxime ligation toolbox.<br>

Bactericidal effect of bovine lactoferrin and synthetic peptide lactoferrin chimera in Streptococcus pneumoniae and the decrease in luxS gene expression by lactoferrin

BioMetals ◽  
2014 ◽  
Vol 27 (5) ◽  
pp. 969-980 ◽  
Author(s):  
Nidia León-Sicairos ◽  
Uriel A. Angulo-Zamudio ◽  
Jorge E. Vidal ◽  
Cynthia A. López-Torres ◽  
Jan G. M. Bolscher ◽  
...  
Keyword(s):  
Gene Expression ◽  
Streptococcus Pneumoniae ◽  
Synthetic Peptide ◽  
Bactericidal Effect ◽  
Bovine Lactoferrin ◽  
Luxs Gene

scholarly journals In Vitro Bactericidal Activity of Human β-Defensin 3 against Multidrug-Resistant Nosocomial Strains

2006 ◽  
Vol 50 (2) ◽  
pp. 806-809 ◽  
Author(s):  
Giuseppantonio Maisetta ◽  
Giovanna Batoni ◽  
Semih Esin ◽  
Walter Florio ◽  
Daria Bottai ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Pseudomonas Aeruginosa ◽  
Antimicrobial Activity ◽  
Bactericidal Activity ◽  
Stenotrophomonas Maltophilia ◽  
Bactericidal Effect ◽  
Multidrug Resistant ◽  
Bacterial Strains ◽  
Gram Negative

ABSTRACT The antimicrobial activity of human β-defensin 3 (hBD-3) against multidrug-resistant clinical isolates of Staphylococcus aureus, Enterococcus faecium, Pseudomonas aeruginosa, Stenotrophomonas maltophilia, and Acinetobacter baumannii was evaluated. A fast bactericidal effect (within 20 min) against all bacterial strains tested was observed. The presence of 20% human serum abolished the bactericidal activity of hBD-3 against gram-negative strains and reduced the activity of the peptide against gram-positive strains.

Effective inhibition of PBPs by cefepime and zidebactam in the presence of VIM-1 drives potent bactericidal activity against MBL-expressing Pseudomonas aeruginosa

2020 ◽  
Vol 75 (6) ◽  
pp. 1474-1478 ◽  
Author(s):  
Bartolome Moya ◽  
Sachin Bhagwat ◽  
Gabriel Cabot ◽  
German Bou ◽  
Mahesh Patel ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Bactericidal Activity ◽  
Bactericidal Effect ◽  
Mouse Lung ◽  
Binding Affinities ◽  
The Novel ◽  
Effective Inhibition ◽  
Mechanistic Basis ◽  
Time Kill ◽  
First Time

Abstract Objectives The combination of cefepime and the novel β-lactam enhancer zidebactam (WCK 5222) is under development for the treatment of difficult-to-treat Gram-negative infections. Against MBL-producing pathogens, cefepime and zidebactam induce cell elongation and spheroplast formation, indicating PBP3 and PBP2 dysfunction, respectively, having a potent bactericidal effect as a combination. The objective of the present study was to determine the mechanistic basis of the bactericidal effect of cefepime/zidebactam on MBL-expressing pathogens. Methods Pseudomonal PBP-binding affinities of cefepime, zidebactam and imipenem were assessed at different timepoints and also in the presence of purified VIM-1 using a Bocillin FL competition assay. The antibacterial activity of cefepime/zidebactam against three VIM-expressing Pseudomonas aeruginosa isolates was assessed by time–kill and neutropenic mouse lung/thigh infection studies. Results Amidst cefepime-hydrolysing concentrations of VIM-1, substantial cefepime binding to target PBPs was observed. High-affinity binding of zidebactam to PBP2 remained unaltered in the presence of VIM-1; however, MBL addition significantly affected imipenem PBP2 binding. Furthermore, the rate of cefepime binding to the primary target PBP3 was found to be higher compared with the imipenem PBP2 binding rate. Finally, complementary PBP inhibition by cefepime/zidebactam resulted in enhanced bactericidal activity in time–kill and neutropenic mouse lung/thigh infection studies against VIM-6-, VIM-10- and VIM-11-expressing P. aeruginosa, thus revealing the mechanistic basis of β-lactam enhancer action. Conclusions For the first time ever (to the best of our knowledge), this study demonstrates that in the presence of VIM-1 MBL, β-lactamase-labile cefepime and β-lactamase-stable zidebactam produce effective inhibition of respective target PBPs. For cefepime, this seems to be a result of a faster rate of PBP binding, which helps it overcome β-lactamase-mediated hydrolysis.

scholarly journals Water Electrolysis in Saturated Phosphate Buffer at Neutral pH

ChemSusChem ◽  
2020 ◽  
Vol 13 (22) ◽  
pp. 5921-5933
Author(s):  
Takahiro Naito ◽  
Tatsuya Shinagawa ◽  
Takeshi Nishimoto ◽  
Kazuhiro Takanabe
Keyword(s):  
Phosphate Buffer ◽  
Water Electrolysis ◽  
Neutral Ph

scholarly journals Evaluation of Double- and Triple-Antibiotic Combinations for VIM- and NDM-Producing Klebsiella pneumoniae byIn VitroTime-Kill Experiments

2014 ◽  
Vol 58 (3) ◽  
pp. 1757-1762 ◽  
Author(s):  
T. Tängdén ◽  
R. A. Hickman ◽  
P. Forsberg ◽  
P. Lagerbäck ◽  
C. G. Giske ◽  
...  
Keyword(s):  
Combination Therapy ◽  
Klebsiella Pneumoniae ◽  
Bactericidal Activity ◽  
Active Drug ◽  
Bactericidal Effect ◽  
Beta Lactamase ◽  
Limited Data ◽  
Content Type ◽  
Bactericidal Effects ◽  
Time Kill

ABSTRACTCombination therapy is recommended for infections with carbapenemase-producingKlebsiella pneumoniae. However, limited data exist on which antibiotic combinations are the most effective. The aim of this study was to find effective antibiotic combinations against metallo-beta-lactamase-producingK. pneumoniae(MBL-KP). Two VIM- and two NDM-producingK. pneumoniaestrains, all susceptible to colistin, were exposed to antibiotics at clinically relevant static concentrations during 24-h time-kill experiments. Double- and triple-antibiotic combinations of aztreonam, ciprofloxacin, colistin, daptomycin, fosfomycin, meropenem, rifampin, telavancin, tigecycline, and vancomycin were used. Synergy was defined as a ≥2 log10decrease in CFU/ml between the combination and its most active drug after 24 h, and bactericidal effect was defined as a ≥3 log10decrease in CFU/ml after 24 h compared with the starting inoculum. Synergistic or bactericidal activity was demonstrated for aztreonam, fosfomycin, meropenem, and rifampin in double-antibiotic combinations with colistin and also for aztreonam, fosfomycin, and rifampin in triple-antibiotic combinations with meropenem and colistin. Overall, the combination of rifampin-meropenem-colistin was the most effective regimen, demonstrating synergistic and bactericidal effects against all four strains. Meropenem-colistin, meropenem-fosfomycin, and tigecycline-colistin combinations were not bactericidal against the strains used. The findings of this and other studies indicate that there is great potential of antibiotic combinations against carbapenemase-producingK. pneumoniae. However, our results deviate to some extent from those of previous studies, which might be because most studies to date have included KPC-producing rather than MBL-producing strains. More studies addressing MBL-KP are needed.

scholarly journals Activity of Human β-Defensin 3 Alone or Combined with Other Antimicrobial Agents against Oral Bacteria

2003 ◽  
Vol 47 (10) ◽  
pp. 3349-3351 ◽  
Author(s):  
Giuseppantonio Maisetta ◽  
Giovanna Batoni ◽  
Semih Esin ◽  
Filippo Luperini ◽  
Manuela Pardini ◽  
...  
Keyword(s):  
Streptococcus Mutans ◽  
Bactericidal Activity ◽  
Lactobacillus Acidophilus ◽  
Antimicrobial Agents ◽  
Bacterial Species ◽  
Bactericidal Effect ◽  
Oral Bacteria ◽  
Actinobacillus Actinomycetemcomitans ◽  
Streptococcus Sobrinus

ABSTRACT The in vitro activities of human β-defensin 3 (hBD-3) alone or combined with lysozyme, metronidazole, amoxicillin, and chlorhexidine were investigated with the oral bacteria Streptococcus mutans, Streptococcus sanguinis, Streptococcus sobrinus, Lactobacillus acidophilus, Actinobacillus actinomycetemcomitans, and Porphyromonas gingivalis. hBD-3 showed bactericidal activity against all of the bacterial species tested. The bactericidal effect was enhanced when the peptide was used in combination with the antimicrobial agents mentioned above.

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