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Sample records for blood bactericidal activity

  1. [Assessment of bactericidal and growth-inhibiting activity of blood serum using flow cytometry and photometry].

    PubMed

    Budikhina, A S; Mikhaĭlova, N A; Bitkova, E E; Khvatov, V B; Pinegin, B V

    2007-01-01

    Method of measurement of biological fluids bactericidal activity against Staphylococcus aureus using laser flow cytometry has been developed and proposed for clinical use. Overall bactericidal activity of sera of healthy donors has been assessed by this method. Strong positive correlation between bactericidal activity measured by flow cytometry and ability of the sera of healthy donors to inhibit bacterial growth assessed by photometric method was determined. High degree of positive correlation between results of cytometry and classical microbiological method of measurement of mentioned parameters has been shown.

  2. Bactericidal activity of black silicon.

    PubMed

    Ivanova, Elena P; Hasan, Jafar; Webb, Hayden K; Gervinskas, Gediminas; Juodkazis, Saulius; Truong, Vi Khanh; Wu, Alex H F; Lamb, Robert N; Baulin, Vladimir A; Watson, Gregory S; Watson, Jolanta A; Mainwaring, David E; Crawford, Russell J

    2013-01-01

    Black silicon is a synthetic nanomaterial that contains high aspect ratio nanoprotrusions on its surface, produced through a simple reactive-ion etching technique for use in photovoltaic applications. Surfaces with high aspect-ratio nanofeatures are also common in the natural world, for example, the wings of the dragonfly Diplacodes bipunctata. Here we show that the nanoprotrusions on the surfaces of both black silicon and D. bipunctata wings form hierarchical structures through the formation of clusters of adjacent nanoprotrusions. These structures generate a mechanical bactericidal effect, independent of chemical composition. Both surfaces are highly bactericidal against all tested Gram-negative and Gram-positive bacteria, and endospores, and exhibit estimated average killing rates of up to ~450,000 cells min(-1) cm(-2). This represents the first reported physical bactericidal activity of black silicon or indeed for any hydrophilic surface. This biomimetic analogue represents an excellent prospect for the development of a new generation of mechano-responsive, antibacterial nanomaterials.

  3. Bactericidal activity of black silicon

    PubMed Central

    Ivanova, Elena P.; Hasan, Jafar; Webb, Hayden K.; Gervinskas, Gediminas; Juodkazis, Saulius; Truong, Vi Khanh; Wu, Alex H.F.; Lamb, Robert N.; Baulin, Vladimir A.; Watson, Gregory S.; Watson, Jolanta A.; Mainwaring, David E.; Crawford, Russell J.

    2013-01-01

    Black silicon is a synthetic nanomaterial that contains high aspect ratio nanoprotrusions on its surface, produced through a simple reactive-ion etching technique for use in photovoltaic applications. Surfaces with high aspect-ratio nanofeatures are also common in the natural world, for example, the wings of the dragonfly Diplacodes bipunctata. Here we show that the nanoprotrusions on the surfaces of both black silicon and D. bipunctata wings form hierarchical structures through the formation of clusters of adjacent nanoprotrusions. These structures generate a mechanical bactericidal effect, independent of chemical composition. Both surfaces are highly bactericidal against all tested Gram-negative and Gram-positive bacteria, and endospores, and exhibit estimated average killing rates of up to ~450,000 cells min−1 cm−2. This represents the first reported physical bactericidal activity of black silicon or indeed for any hydrophilic surface. This biomimetic analogue represents an excellent prospect for the development of a new generation of mechano-responsive, antibacterial nanomaterials. PMID:24281410

  4. Human lipopolysaccharide-binding protein potentiates bactericidal activity of human bactericidal/permeability-increasing protein.

    PubMed Central

    Horwitz, A H; Williams, R E; Nowakowski, G

    1995-01-01

    Human bactericidal/permeability-increasing protein (BPI) from neutrophils and a recombinant amino-terminal fragment, rBPI23, bind to and are cytotoxic for gram-negative bacteria both in vitro and ex vivo in plasma or whole blood. To function in vivo as an extracellular bactericidal agent, rBPI23 must act in the presence of the lipopolysaccharide-binding protein (LBP), which also binds to but has no reported cytotoxicity for gram-negative bacteria. LBP, which is present at 5 to 10 micrograms/ml in healthy humans and at much higher levels in septic patients, mediates proinflammatory host responses to gram-negative infection. On the basis of these previous observations, we have examined the effect of recombinant LBP (rLBP) on the bactericidal activity of rBPI23 against Escherichia coli J5 in vitro. Physiological concentrations of rLBP (5 to 20 micrograms/ml) had little or no bactericidal activity but reduced by up to approximately 10,000-fold the concentration of BPI required for bactericidal or related activities in assays which measure (i) cell viability as CFUs on solid media or growth in broth culture and (ii) protein synthesis following treatment with BPI. LBP also potentiated BPI-mediated permeabilization of the E. coli outer membrane to actinomycin D by about 100-fold but had no permeabilizing activity of its own. Under optimal conditions for potentiation, fewer than 100 BPI molecules were required to kill a single E. coli J5 bacterium. PMID:7822017

  5. Bactericidal activity of biomimetic diamond nanocone surfaces.

    PubMed

    Fisher, Leanne E; Yang, Yang; Yuen, Muk-Fung; Zhang, Wenjun; Nobbs, Angela H; Su, Bo

    2016-03-17

    The formation of biofilms on implant surfaces and the subsequent development of medical device-associated infections are difficult to resolve and can cause considerable morbidity to the patient. Over the past decade, there has been growing recognition that physical cues, such as surface topography, can regulate biological responses and possess bactericidal activity. In this study, diamond nanocone-patterned surfaces, representing biomimetic analogs of the naturally bactericidal cicada fly wing, were fabricated using microwave plasma chemical vapor deposition, followed by bias-assisted reactive ion etching. Two structurally distinct nanocone surfaces were produced, characterized, and the bactericidal ability examined. The sharp diamond nanocone features were found to have bactericidal capabilities with the surface possessing the more varying cone dimension, nonuniform array, and decreased density, showing enhanced bactericidal ability over the more uniform, highly dense nanocone surface. Future research will focus on using the fabrication process to tailor surface nanotopographies on clinically relevant materials that promote both effective killing of a broader range of microorganisms and the desired mammalian cell response. This study serves to introduce a technology that may launch a new and innovative direction in the design of biomaterials with capacity to reduce the risk of medical device-associated infections.

  6. Bactericidal activity of partially oxidized nanodiamonds.

    PubMed

    Wehling, Julia; Dringen, Ralf; Zare, Richard N; Maas, Michael; Rezwan, Kurosch

    2014-06-24

    Nanodiamonds are a class of carbon-based nanoparticles that are rapidly gaining attention, particularly for biomedical applications, i.e., as drug carriers, for bioimaging, or as implant coatings. Nanodiamonds have generally been considered biocompatible with a broad variety of eukaryotic cells. We show that, depending on their surface composition, nanodiamonds kill Gram-positive and -negative bacteria rapidly and efficiently. We investigated six different types of nanodiamonds exhibiting diverse oxygen-containing surface groups that were created using standard pretreatment methods for forming nanodiamond dispersions. Our experiments suggest that the antibacterial activity of nanodiamond is linked to the presence of partially oxidized and negatively charged surfaces, specifically those containing acid anhydride groups. Furthermore, proteins were found to control the bactericidal properties of nanodiamonds by covering these surface groups, which explains the previously reported biocompatibility of nanodiamonds. Our findings describe the discovery of an exciting property of partially oxidized nanodiamonds as a potent antibacterial agent.

  7. Rapid bactericidal activity of sitafloxacin against Streptococcus pneumoniae.

    PubMed

    Kanda, Hiroko; Inoue, Kazue; Okumura, Ryo; Hoshino, Kazuki

    2013-02-01

    The initial bactericidal activity of quinolones against Streptococcus pneumoniae at the concentration equivalent to their respective peak serum concentration (C(max)) and free drug fraction of C(max) (fC(max)) were investigated. The bactericidal activity of sitafloxacin (STFX), levofloxacin (LVFX), moxifloxacin (MFLX), and garenoxacin (GRNX) were compared by determining the actual killing of bacteria at C(max) and fC(max) for 1 and 2 hours based on the Japanese maximum dose per administration (100, 500, 400, and 400 mg, respectively). Against 4 quinolone-susceptible clinical isolates (wild-type), STFX with C(max) and fC(max) exhibited the most rapid bactericidal activity resulting in an average reduction of > or = 3.0 log10 colony forming units (CFU)/ mL in 1 hour. STFX with C(max) and fC(max) also showed the most rapid and potent bactericidal activity against 9 clinical isolates with single par (C/E) mutation, resulting in > or = 3.0 log10 CFU/mL average reduction in viable cells in 1 hour. STFX showed a statistically significant advantage in initial bactericidal activity over other quinolones for single mutants (P < 0.001). The propensity that the difference in the initial bactericidal activity between STFX and other quinolones was higher in single mutants than wild-type strains, was confirmed using S. pneumoniae ATCC49619 (wild-type) and its laboratory single parC mutant. As a result, STFX showed a similar rapid and potent initial bactericidal activity against both strains, while initial bactericidal activity for other quinolones was significantly reduced in the single mutant (P < 0.05). In conclusion, STFX has the most rapid and potent initial bactericidal activity against wild-type and single mutants of S. pneumoniae and its bactericidal activity is not affected by the presence of a single par mutation compared to LVFX, MFLX, and GRNX.

  8. [Bactericidal activity of colloidal silver against grampositive and gramnegative bacteria].

    PubMed

    Afonina, I A; Kraeva, L A; Tseneva, G Ia

    2010-01-01

    It was shown that colloidal silver solution prepared in cooperation with the A. F. Ioffe Physical Technical Institute of the Russian Academy of Sciences, had significant bactericidal activity. Stable bactericidal effect on gramnegative microorganisms was observed after their 2-hour exposition in the solution of colloidal silver at a concentration of 10 ppm. Grampositive capsule-forming microorganisms were less susceptible to the colloidal silver solution: their death was observed after the 4-hour exposition in the solution.

  9. [Bactericidal activity of sitafloxacin and other new quinolones against antimicrobial resistant Streptococcus pneumoniae].

    PubMed

    Kobayashi, Intetsu; Kanayama, Akiko; Hasegawa, Miyuki; Kaneko, Akihiro

    2013-02-01

    We conducted a study assess the bactericidal activity of sitafloxacin (STFX) against Streptococcus pneumoniae isolates recovered from respiratory infections including penicillin-resistant (PRSP) isolates, macrolide resistant isolates possessing mefA and ermB resistance genes and quinolone resistance isolates with mutations in gyrA or gyrA and parC. Each isolate tested was grown in hemosupplemented Mueller-Hinton broth and adjusted to approximately 10(5) CFU/ mL. Isolates were than exposed to a Cmax antimicrobial blood level that would be attained with routine antimicrobial administration and an antimicrobial level that would be expected 4 hours post-Cmax (Cmax 4hr). Bactericidal activity was measured for up to 8 hours. Excluding a subset of S. pneumoniae isolates with mutations in the quinolone resistance determining region (QRDR), all quinolones showed bactericidal activity at Cmax and Cmax 4 hr antimicrobial concentrations for up to 8 hours. Against S. pneumoniae isolates with either gyrA or gyrA and parC mutations, bactericidal activity of STFX was shown for up to 4 to 8 hours following Cmax based on a limit of detection of < 1.3 log CFU/mL. Garenoxacin (GRNX) did not showed bactericidal activity below the limit of detection for up to 8 hours with exposure to Cmax and no bactericidal activity was seen with levofloxacin. When all quinolones tested where adjusted to concentrations corresponding to their MICs, STFX showed the most rapid bactericidal activity against PRSP. This rapid bactericidal activity in PRSP is a key to the effectiveness of STFX. Our findings show that beyond inhibition of bacterial replication by blocking their DNA replication pathway and synthesis of proteins, STFX demonstrated characteristics contributing to greater bactericidal activity compared to GRNX. In conclusion, of the newer quinolones, STFX showed the strongest bactericidal activity against S. pneumoniae isolates with mutations in the QRDR which indicates that it may show the most

  10. Effect of ovarian hormones on promotion of bactericidal activity by uterine secretions of ovariectomized mares.

    PubMed

    Watson, E D; Stokes, C R; David, J S; Bourne, F J

    1987-03-01

    The bactericidal and phagocytic activities of blood neutrophils suspended in uterine washings and the mobilization of neutrophils into the uterine lumen were studied in ovariectomized mares receiving oestradiol benzoate (N = 4), progesterone (N = 4) or oily vehicle (N = 4). Uterine lavage was performed sequentially up to 144 h after induction of endometritis by intrauterine infusion of glycogen (1%). There was no significant difference between the 3 groups in speed of mobilization of neutrophils into the uterus in the first 6 h after infusion but there were significantly more uterine luminal neutrophils in progesterone-treated than in oestradiol-treated mares by 24 h after infusion (P less than 0.01). Uterine washings collected from progesterone-treated mares at 0, 24 and 144 h were significantly worse at promoting bactericidal activity by neutrophils than washings from oestradiol-treated and control mares (P less than 0.001). In oestrogen-treated and control mares bactericidal activity had increased by 144 h but in progesterone-treated mares bactericidal activity remained low. Neither treatment nor time affected the ability of washings to opsonize yeast blastospores. Elevated concentrations of progesterone in plasma were therefore associated with decreased bactericidal activity of neutrophils suspended in uterine washings but the generation of C3b in washings did not appear to be affected by hormone treatment.

  11. Bactericidal activity of glutaraldehyde-like compounds from olive products.

    PubMed

    Medina, Eduardo; Brenes, Manuel; García, Aranzazu; Romero, Concepción; de Castro, Antonio

    2009-12-01

    The bactericidal effects of several olive compounds (nonenal, oleuropein, tyrosol, the dialdehydic form of decarboxymethyl elenolic acid either free [EDA] or linked to tyrosol [TyEDA] or to hydroxytyrosol [HyEDA]), other food phenolic compounds (catechin, epicatechin, eugenol, thymol, carvacrol, and carnosic acid), and commercial disinfectants (glutaraldehyde [GTA] and ortho-phthalaldehyde [OPA]), were tested against strains of Pseudomonas fluorescens, Staphylococcus aureus, Enterococcus faecalis, and Escherichia coli. It was found that the bactericidal activities of olive GTA-like compounds (EDA, HyEDA, and TyEDA) were greater than those exerted by several food phenolic substances. Surprisingly, these olive antimicrobials were as active as the synthetic biocides GTA and OPA against the four bacteria studied. Thus, it has been proposed that the bactericidal activity of the main olive antimicrobials is primarily due to their dialdehydic structure, which is similar to that of the commercial biocides GTA and OPA. Our results clearly reveal that olive GTA-like compounds possess a strong bactericidal activity even greater than that of other food phenolic compounds or synthetic biocides.

  12. Nonionic surfactants enhancing bactericidal activity at their critical micelle concentrations.

    PubMed

    Tobe, Seiichi; Majima, Toshiaki; Tadenuma, Hirohiko; Suekuni, Tomonari; Sakai, Kenichi; Sakai, Hideki; Abe, Masahiko

    2015-01-01

    Bactericidal activities of benzalkonium chloride [also known as alkyldimethylbenzylammonium chloride (ADBAC)] containing nonionic surfactants such as methyl ester ethoxylates (MEE) with the alkyl group C8-C14 and oxyethylene (EO) group of average adduct number 3-15 were measured against Escherichia coli and Staphylococcus aureus. Sample solutions containing MEE in the vicinity of the critical micelle concentration exhibited a dramatic decrease in viable bacterial counts. MEE with an alkyl group of C12 and an oxyethylene group of lower adduct number exhibited little viable bacterial counts than those having higher EO adduct numbers. MEE with reduced EO adduct numbers increased fluorescence intensity in E. coli using the viability stain SYTO 9. Our results show that MEE molecules with low EO adduct numbers exhibited bactericidal activity by increasing the permeability of the E. coli cell membrane. Sample solution containing ADBAC and MEE molecules with lower EO adduct numbers also displayed higher zeta potentials. Moreover, ADBAC molecules incorporated into micelles of MEE with lower EO adduct numbers were adsorbed onto the surface of E. coli, which augmented bactericidal activity.

  13. Bactericidal activity of Pistacia lentiscus mastic gum against Helicobacter pylori.

    PubMed

    Marone, P; Bono, L; Leone, E; Bona, S; Carretto, E; Perversi, L

    2001-12-01

    In this study we evaluated the antibacterial activity of mastic gum, a resin obtained from the Pistacia lentiscus tree, against clinical isolates of Helicobacter pylori. The minimal bactericidal concentrations (MBCs) were obtained by a microdilution assay. Mastic gum killed 50% of the strains tested at a concentration of 125 microg/ml and 90% at a concentration of 500 microg/ml. The influence of sub-MBCs of mastic gum on the morphologies of H. pylori was evaluated by transmission electron microscopy. The lentiscus resin induced blebbing, morphological abnormalities and cellular fragmentation in H. pylori cells.

  14. Relationship between peptide membrane curvature generation and bactericidal activities

    NASA Astrophysics Data System (ADS)

    Schmidt, Nathan; Lee, Michelle; Kuo, David; Ouellette, Andre; Wong, Gerard

    2013-03-01

    Many amphipathic peptides and amphipathic domains in proteins can restructure biological membranes. Two examples are host defense antimicrobial peptides (AMPs) which disrupt and destabilize the cell membranes of microbes, and apolipoproteins which help stabilize nanoscale lipid aggregates. We use complementary x-ray and bacterial cell assays to elucidate the molecular length scale membrane deformations generated by amphipathic peptides with different structural motifs and relate these deformations to their activities on bacteria. Small angle x-ray scattering is used to study the interactions of model membranes with prototypical AMPs and consensus peptides from the amphipathic domains in apolipoproteins. By characterizing the nanoscale curvature deformations induced by these two distinct classes of membrane restructuring peptides we will discuss the role of amino acid composition on curvature generation. Bactericidal assays are used to access the in vivo activities of different amphipathic peptide motifs in order to understand the relationships between cell viability and membrane curvature generation.

  15. Antibodies to Meningococcal H.8 (Lip) Antigen Fail to Show Bactericidal Activity

    DTIC Science & Technology

    1990-01-01

    monoclonaux n’avaient pas non plus d’activit6 bactericide contre ces souches. La faible activitt bactdricide associee aux anticorps monoclonaux et...MENINGOCOCCAL H.8 (Lip) ANTIGEN FAILTO SHOW BACTERICIDAL ACTIVITY. 12. PERSONAL. DUTHOR(S AK BHATTACHARJEE, EE MORAN, & WD ZOLLINGER. lb. TMP OP REPORT DATE...isotypes. An anti-Lip mouse monoclonal ascites (2-1-CA2) had 28 400 ELISA units of antibody. Bactericidal assays were performed using three different

  16. Early and Extended Early Bactericidal Activity of Linezolid in Pulmonary Tuberculosis

    PubMed Central

    Dietze, Reynaldo; Hadad, David Jamil; McGee, Bryan; Molino, Lucilia Pereira Dutra; Maciel, Ethel Leonor Noia; Peloquin, Charles A.; Johnson, Denise F.; Debanne, Sara M.; Eisenach, Kathleen; Boom, W. Henry; Palaci, Moises; Johnson, John L.

    2008-01-01

    Rationale: Linezolid, the first oxazolidinone approved for clinical use, has effective in vitro and promising in vivo activity against Mycobacterium tuberculosis. Objectives: To evaluate the early and extended early bactericidal activity of linezolid in patients with pulmonary tuberculosis. Methods: Randomized open label trial. Thirty patients with newly diagnosed smear-positive pulmonary tuberculosis (10 per arm) were assigned to receive isoniazid (300 mg daily) and linezolid (600 mg twice daily or 600 mg once daily) for 7 days. Sputum for quantitative culture was collected for 2 days before and then daily during 7 days of study drug administration. Bactericidal activity was estimated by measuring the decline in bacilli during the first 2 days (early bactericidal activity) and the last 5 days of study drug administration (extended early bactericidal activity). Measurements and Main Results: The mean early bactericidal activity of isoniazid (0.67 log10 cfu/ml/d) was greater than that of linezolid twice and once daily (0.26 and 0.18 log10 cfu/ml/d, respectively). The extended early bactericidal activity of linezolid between Days 2 and 7 was minimal. Conclusions: Linezolid has modest early bactericidal activity against rapidly dividing tubercle bacilli in patients with cavitary pulmonary tuberculosis during the first 2 days of administration, but little extended early bactericidal activity. Clinical trial registered with www.clinicaltrials.gov (NCT00396084). PMID:18787216

  17. [Bactericidal activity of serum and chemotherapy in sensitive and resistant exciter (author's transl)].

    PubMed

    Eyer, H; Metz, H; Preac-Mursic, V

    1975-11-21

    Comparing examinations with Ampicillin sensitive and resistant bacteria-strains show that the bactericidal activity of serum is dependent on the bacteria-strains, on the Ampicillin sensitivity of the particular exciter and on the number of bacteria/ml (germ count). Bactericide effect could always be obtained with sensitive strains as a result of additional chemotherapy. With several resistant strains a bactericide effect could not be obtained in this case the continuous optimal Ampicillin addition was the decisive factor. Because of the extremely complicated process of the bactericide one should not make general conclusions from the individual experimental results.

  18. Preparation and bactericide activity of gallic acid stabilized gold nanoparticles

    NASA Astrophysics Data System (ADS)

    Moreno-Álvarez, S. A.; Martínez-Castañón, G. A.; Niño-Martínez, N.; Reyes-Macías, J. F.; Patiño-Marín, N.; Loyola-Rodríguez, J. P.; Ruiz, Facundo

    2010-10-01

    In this work, gold nanoparticles with three different sizes (13.7, 39.4, and 76.7 nm) were prepared using a simple aqueous method with gallic acid as the reducing and stabilizing agent, the different sizes were obtained varying some experimental parameters as the pH of the reaction and the amount of the gallic acid. The prepared nanoparticles were characterized using X-ray diffraction, transmission electron microscopy, dynamic light scattering, and UV-Vis spectroscopy. Samples were identified as elemental gold and present spherical morphology, a narrow size distribution and good stabilization according to TEM and DLS results. The antibacterial activity of this gallic acid stabilized gold nanoparticles against S. mutans (the etiologic agent of dental caries) was assessed using a microdilution method obtaining a minimum inhibitory concentration of 12.31, 12.31, and 49.25 μg/mL for 13.7, 39.4, and 76.7 nm gold nanoparticles, respectively. The antibacterial assay showed that gold nanoparticles prepared in this work present a bactericide activity by a synergistic action with gallic acid. The MIC found for this nanoparticles are much lower than those reported for mixtures of gold nanoparticles and antibiotics.

  19. Differential analysis of bactericidal systems of blood serum with recombinant luminescent Escherichia coli and Bacillus subtilis strains.

    PubMed

    Deryabin, D G; Karimov, I F; Manukhov, I V; Tolmacheva, N A; Balabanov, V P

    2012-11-01

    Luminescence intensity of recombinant Escherichia coli and Bacillus subtilis strains with cloned luxCD(AB)E genes of the natural luminescent microorganism Photobacterium leiognathi was studied under the influence of 30 individual samples of human blood serum of different component composition. A relationship was found between the level of residual bioluminescence and degree of the bactericidal effect. Moreover, the inhibition of E. coli lux+ luminescence was shown to be related to activity of the complement-lysozyme system. The reaction of B. subtilis lux+ primarily depended on the presence of β-lysin in the blood serum. These data provide an experimental substantiation of a new method of differential analysis of humoral factors of nonspecific innate immunity with recombinant luminescent bacteria.

  20. Bactericidal activity of synthetic peptides based on the structure of the 55-kilodalton bactericidal protein from human neutrophils.

    PubMed Central

    Gray, B H; Haseman, J R

    1994-01-01

    Short (10- to 11-mer) hydrophilic peptides based on the structure of the 55-kDa bactericidal protein (BP55, B/PI, and CAP57) from human neutrophil granules were identified from the hydropathy plot of the 456-amino-acid sequence predicted from the nucleotide sequences of cDNA clones for BP55 and B/PI. Peptides corresponding to amino acid residues 90 to 99 (peptide #90-99), 86 to 99, or 90 to 102 of BP55 were bactericidal toward 5 x 10(6) Pseudomonas aeruginosa cells at 0.6 x 10(-5) to 1.5 x 10(-5) M and killed an Escherichia coli rough strain at 3 x 10(-5) M. The #90-99 peptide with a cysteine added at the amino terminus (C#90-99) was approximately 10 times more active than #90-99, killing P. aeruginosa at 1.5 x 10(-6) M. Peptides representing amino acid residues 27 to 37, 118 to 127, and 160 to 170 and the first 10 amino acids of the signal sequence for BP55 were not bactericidal. When coupled to either keyhole limpet hemocyanin or ovalbumin protein carriers through the thiol group, the C#90-99 peptide was not diminished on a molar basis in its capacity for killing of P. aeruginosa. Two other relatively hydrophilic peptides with an added amino-terminal cysteine, peptides C#227-236 and C#418-427, were not bactericidal at 1.2 x 10(-4) M or at 100 times the effective bactericidal concentration of C#90-99. The C#90-99 peptide killed E. coli at 1.5 x 10(-5) M, or at 10 times the concentration required to kill an equal number of P. aeruginosa cells. Although Pseudomonas cepacia and Staphylococcus aureus were resistent to killing by the parent BP55 molecule, they were susceptible to the C#90-99 and #90-99 peptides in the same concentration range as was E. coli. When all peptides were compared for the ability to neutralize E. coli O55:B5 endotoxin in a Limulus amoebocyte lysate assay, the C#227-236, C#418-427, and #160-170 peptides completely inhibited gelation at a 10(-4) M concentration. All other synthetic peptides, including bactericidal peptide #90-99 and its

  1. Bactericidal activities of selected organic N-halamines.

    PubMed Central

    Williams, D E; Worley, S D; Barnela, S B; Swango, L J

    1987-01-01

    The bactericidal efficacies of three organic N,N'-dihalamine disinfectants in the class of compounds termed imidazolidinones were determined for combinations of pH, temperature, and water quality treatments by using Staphylococcus aureus and Shigella boydii as test organisms. The compound 1,3-dibromo-4,4,5,5-tetramethyl-2-imidazolidinone was found to be the most rapidly acting bactericide, especially under halogen-demand-free conditions. The mixed N,N'-dihalamine 1-bromo-3-chloro-4,4,5,5-tetramethyl-2-imidazolidinone was found to be intermediate in terms of rate of disinfection, while the compound 1,3-dichloro-4,4,5,5-tetramethyl-2-imidazolidinone was observed to be the slowest acting bactericide. When overall effectiveness was judged on the basis of stability of the disinfectants along with rates of disinfection, the mixed halamine was considered to exhibit great potential for use as a disinfectant in an aqueous solution. PMID:3314705

  2. Antimicrobial Peptides Containing Unnatural Amino Acid Exhibit Potent Bactericidal Activity against ESKAPE Pathogens

    DTIC Science & Technology

    2013-01-01

    Antimicrobial peptides containing unnatural amino acid exhibit potent bactericidal activity against ESKAPE pathogens R. P. Hicks a, J. J. Abercrombie...tic classes, membrane-disruptors and non -membrane-disrup- tors.30,31 Five different mechanisms have been proposed at one time or another to explain...DATES COVERED - 4. TITLE AND SUBTITLE Antimicrobial Peptides Containing Unnatural Amino Acid Exhibit Potent Bactericidal Activity Against

  3. Antibodies to meningococcal H.8 (Lip) antigen fail to show bactericidal activity.

    PubMed

    Bhattacharjee, A K; Moran, E E; Zollinger, W D

    1990-02-01

    Purified H.8 (Lip) antigen was coupled to tresyl-activated Sepharose 4B and used in affinity columns to purify anti-Lip antibodies from convalescent patient sera and from immune rabbit sera. Affinity-purified anti-Lip antibodies isolated from two convalescent patient sera contained 1000 and 1280 ELISA units of antibody and included antibodies of IgG, IgA, and IgM isotypes. An anti-Lip mouse monoclonal ascites (2-1-CA2) had 28,400 ELISA units of antibody. Bactericidal assays were performed using three different case strains of Neisseria meningitidis group B, namely 44/76, 8532, and 8047. Neither preparation of purified human anti-Lip antibodies had detectable bactericidal activity against strains 44/76 and 8532, but one of the two had a titer of 1:4 against strain 8047. Anti-Lip antibodies that were purified from immune rabbit serum and contained 1600 ELISA units of anti-Lip antibodies also failed to show detectable bactericidal activity. The rabbits were immunized with purified Lip antigen and showed specific antibody levels of 2000-2200 units by ELISA, but even the unfractionated sera had little or no bactericidal activity against the test strains. The high titer mouse monoclonal ascites had no bactericidal activity against the test strains. The poor bactericidal activity associated with monoclonal and polyclonal antibodies to the Lip antigen suggest that in spite of other attractive properties it may not be useful as a meningococcal vaccine.

  4. Bactericidal Activities of HMR 3647, Moxifloxacin, and Rifapentine against Mycobacterium leprae in Mice

    PubMed Central

    Consigny, Sophie; Bentoucha, Abdelhalim; Bonnafous, Pascale; Grosset, Jacques; Ji, Baohong

    2000-01-01

    Bactericidal activities of HMR 3647 (HMR), moxifloxacin (MXFX), and rifapentine (RPT) against Mycobacterium leprae, measured by the proportional bactericidal technique in the mouse footpad system, were compared with those of the established antileprosy drugs clarithromycin (CLARI), ofloxacin (OFLO), and rifampin (RMP). Administered in five daily doses of 100 mg/kg of body weight, HMR appeared slightly more bactericidal than CLARI. In a single dose, MXFX at 150 mg/kg was more active than the same dose of OFLO and displayed exactly the same level of activity as RMP at 10 mg/kg; the combination MXFX-minocycline (MINO) (MM) was more bactericidal than the combination OFLO-MINO (OM); RPT at 10 mg/kg was more bactericidal than the same dose of RMP and even more active than the combination RMP-OFLO-MINO (ROM); the combination RPT-MXFX-MINO (PMM) killed 99.9% of viable M. leprae and was slightly more bactericidal than RPT alone, indicating that the combination PMM showed an additive effect against M. leprae. PMID:10991891

  5. Bactericidal activity of penicillin, ceftriaxone, gentamicin and daptomycin alone and in combination against Aerococcus urinae.

    PubMed

    Hirzel, Cédric; Hirzberger, Lea; Furrer, Hansjakob; Endimiani, Andrea

    2016-09-01

    Aerococcus urinae can cause severe infections (bacteraemia and endocarditis) that are associated with high mortality. However, data on the bactericidal and synergistic activity for clinically implemented antibiotics are scarce. Time-kill analyses were performed on two clinical isolates (AU1 and AU2) and the reference strain ATCC 700306 for penicillin (PG), ceftriaxone (CRO), gentamicin (GEN), daptomycin (DAP) and their combinations. AU1 and AU2 were CRO-resistant (MICs, 2 µg/mL) and ATCC 700306 was high-level GEN-resistant (MIC, 512 µg/mL), whereas all strains were PG- and DAP-susceptible (MICs, ≤0.125 and ≤1 µg/mL, respectively). CFU counts were determined at various time points from 0 to 48 h. All experiments were performed at 0.5×, 1×, 2× and 4× MIC. PG and CRO were not bactericidal for all strains, whereas DAP exhibited bactericidal activity at all concentrations for AU2 and ATCC 700306. The combination of PG or CRO with GEN was bactericidal for AU1 and AU2 at antibiotic concentrations ≥1× MIC. Bactericidal synergism was detected for PG or CRO combined with GEN in the two clinical isolates. PG plus CRO showed non-bactericidal synergism for ATCC 700306. DAP with GEN was synergistic at 1× MIC for AU1, whereas the killing activity of DAP was too pronounced to detect potential synergism in AU2. The combination of PG or CRO with GEN is synergistic and bactericidal. Moreover, these in vitro data suggest that DAP may represent a potential bactericidal treatment alternative against A. urinae. This finding could be important for the treatment of patients with a β-lactam allergy or renal insufficiency.

  6. [Kinetics of in vitro bactericidal activity of the antiseptic biseptine combining 3 active principles].

    PubMed

    Reverdy, M E; Rougier, M; Fleurette, J

    1996-09-01

    Biseptine, is an association of chlorhexidine digluconate, benzalkonium chloride and benzylic alcohol. Little is known, in literature, on this antiseptic, used for cutaneous antisepsis. We studied killing kinetic of Biseptine, at different concentrations, on 4 AFNOR bacterial strains. Killing curves were studied at antiseptic concentration of 90 to 0.1% in 10 ml of distilled water. Bacterial counts were determined after neutralization in liquid medium. Synergy of chlorhexidine and benzalkonium chloride in Biseptine, allowed to obtain similar bactericidal activity than Hibitane champ with chlorhexidine concentrations 2 fold less. At 90, 50, 25, 10 and 5% concentrations, bactericidal activity (5 log10 reduction of the initial bacterial count) was effective in one minute. After 5 to 15 minutes, activity persisted at 1 and 0.5% concentrations. The 0.1% solution was inefficacious. This report disclosed an important security margin in antiseptic activity.

  7. Effects of penicillinase on bactericidal and complement activities in normal human serum.

    PubMed Central

    Biggs, W H; Wunderlich, A C; Corbeil, L C; Davis, C E; Curd, J G

    1983-01-01

    During routine addition of penicillinase (beta-lactamase) to patients sera, we found that the capacity of some of these sera to kill serum-sensitive gram-negative organisms was significantly decreased. Further controlled studies showed that penicillinase decreased both the bactericidal activity of normal human sera and the total hemolytic activity (CH50) of complement in these sera. The decreased bactericidal activity correlated significantly (r = 0.57, P less than 0.05) with the reduction of CH50 in eight normal sera. These effects of penicillinase were time and temperature dependent. Measurement of individual complement component activities showed that penicillinase decreased the activity of C2, C4, and C3-C9, suggesting that the penicillinase preparation activated the classical pathway. These results cast doubts on the validity of bactericidal determinations when sera are pretreated with penicillinase. PMID:6603195

  8. Galangin expresses bactericidal activity against multiple-resistant bacteria: MRSA, Enterococcus spp. and Pseudomonas aeruginosa.

    PubMed

    Pepeljnjak, Stjepan; Kosalec, Ivan

    2004-11-01

    The antimicrobial activity of three propolis ethanol extracts (EEP) was examined for various Gram-negative and Gram-positive bacterial species, including multiple-resistant Staphylococcus aureus, Enterococcus spp. and Pseudomonas aeruginosa strains. EEP had a good bactericidal activity against Gram-positive species, and all multiple-resistant bacterial strains tested were sensitive to EEP. Minimal inhibitory concentrations (MICs) were lower in samples of higher flavonoid content (from 0.65 to 7.81 mg mL(-1)), indicating the influence of the concentration of some potent bactericidal compound(s) in propolis or synergism among some bactericidal compounds. Antimicrobial-guided separation of flavonoid aglycones (bioassay in situ on thin-layer chromatogram) showed that galangin (3,5,7-trihydroxyflavone) is one compound in EEP with bactericidal activity. Galangin was isolated by preparative chromatography. After determining the quantity present, the MIC against multiple-resistant bacteria was determined. The MIC of galangin against multiple-resistant bacterial strains was significantly lower (from 0.16 to 0.44 mg mL(-1), p < 0.05) than that of EEP. The bactericidal activity of galangin against P. aeruginosa strains was present at 0.17+/-0.05 mg mL(-1).

  9. The behavior of active bactericidal and antifungal coating under visible light irradiation

    NASA Astrophysics Data System (ADS)

    Xiao, Gang; Zhang, Xiaodong; Zhao, Yan; Su, Haijia; Tan, Tianwei

    2014-02-01

    In the present paper, the novel active bactericidal and antifungal coatings (ABAC) have been prepared through the immobilization of Fe-doped TiO2 (anatase) with chitosan. The characterization of ABAC using optical microscope imaging, SEM, AFM and FTIR shows that the Fe doped TiO2 is embedded into the chitosan coating with favorable dispersion through the hydrogen bonds interaction between chitosan molecules and TiO2. The contact angle measurement demonstrated the hydrophilicity of ABAC (θ = 34.5 ± 4.1°). The bactericidal activity of ABAC has been evaluated by inactivating three different test strains: Escherichia coli, Candida albicans and Aspergillus niger which illustrates the apparently higher bactericidal ability than chitosan, Fe-TiO2 and chitosan/TiO2 (pure) under visible light irradiation and its bactericidal activity is lasting for at least 24 h. ABAC showed rapid and efficient antibacterial ability for the three tested strains and its antibacterial ratio in 2 h for E. coli, C. albicans and A. niger was 99.9%, 97.0% and 95.0%, respectively. The prepared chitosan/TiO2 composite emulsion shows favorable storage stability and can be stored up to 1 year without losing its bactericidal activity. ABAC is a low-cost and eco-friendly antibacterial coating products and promising for domestic, medical and industrial applications.

  10. Role of capsule and O antigen in resistance of Klebsiella pneumoniae to serum bactericidal activity.

    PubMed Central

    Tomás, J M; Benedí, V J; Ciurana, B; Jofre, J

    1986-01-01

    The ability of Klebsiella pneumoniae strains to resist the bactericidal activity of serum was quantitated. The K. pneumoniae strains tested included mutants lacking the capsular polysaccharide and mutants having a modified lipopolysaccharide structure. The last mutants were obtained as phage-resistant mutants, and their lipopolysaccharide was characterized by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and chemical analysis. Serum-resistant mutants derived from phage-resistant mutants (lipopolysaccharide mutants) were also characterized. Resistance to the bactericidal activity of complement was mediated by the lipopolysaccharide, especially by the O-antigen polysaccharide chains. The capsular polysaccharide seemed not to play any important role in resistance to serum bactericidal activity in this bacterium. Images PMID:3531020

  11. Effects of refrigeration on the bactericidal activity of human milk: a preliminary study.

    PubMed

    Martínez-Costa, Cecilia; Silvestre, María Dolores; López, María Carmen; Plaza, Auxiliadora; Miranda, María; Guijarro, Raquel

    2007-08-01

    This study analyzed the bactericidal activity of human milk and how it is influenced by refrigerated storage. Nine samples of mature human milk were collected and divided into 3 aliquots. One was analyzed immediately, and the other 2 were refrigerated at 4 degrees C to 6 degrees C for 48 and 72 hours, respectively. All of the fresh samples exhibited bactericidal activity with an average value of 83.47% +/- 18.37%. Refrigeration for 48 hours did not cause significant modifications, whereas storage beyond 72 hours significantly lowered the degree of bacteriolysis versus fresh milk. In conclusion, human milk possesses bactericidal activity that remains stable during the first 48 hours of refrigerated storage, but it is significantly reduced beyond 72 hours.

  12. Lactobacillus Proteins Are Associated with the Bactericidal Activity against E. coli of Female Genital Tract Secretions

    PubMed Central

    Kalyoussef, Sabah; Nieves, Edward; Dinerman, Ellen; Carpenter, Colleen; Shankar, Viswanathan; Oh, Jamie; Burd, Berta; Angeletti, Ruth H.; Buckheit, Karen W.; Fredricks, David N.; Madan, Rebecca P.; Keller, Marla J.; Herold, Betsy C.

    2012-01-01

    Background Female genital tract secretions are bactericidal for Escherichia (E.) coli ex vivo. However, the intersubject variability and molecules that contribute to this activity have not been defined. Methods The bactericidal activity and concentration of immune mediators in cervicovaginal lavage (CVL) collected from 99 healthy women were determined. Results CVL reduced the number of E. coli colonies by 68% [−26, 100] (median [range]). CVL were active against laboratory and clinical isolates of E. coli, but were inactive against Lactobacillus species. Bactericidal activity correlated with the concentration of protein recovered (p<0.001), but not with cytokines, chemokines or antimicrobial peptides. Four CVL with>90% inhibitory activity (active) and two with<30% activity were subjected to MS/MS proteomic analysis. 215 proteins were identified and six were found exclusively in active samples. Four of these corresponded to Lactobacillus crispatus or jensenii proteins. Moreover, culture supernatants from Lactobacillus jensenii were bactericidal for E. coli. Conclusion Both host and commensal microbiota proteins contribute to mucosal defense. Identification of these proteins will facilitate the development of strategies to maintain a healthy vaginal microbiome and prevent colonization with pathogenic bacteria such as E. coli that increase the risk for urinary tract infections, preterm labor and perinatal infection. PMID:23185346

  13. Bactericidal and sporicidal activities of an improved iodide formulation and its derivative.

    PubMed

    Kida, Nori

    2009-09-01

    Bactericidal and sporicidal activities of an improved iodide formulation (tentatively designated as the distilled KMT reagent: pH around 3) and its derivative (tentatively designated as the distilled ethanol reagent: pH around 2.5) were examined in several dilutions against vegetative bacteria and Bacillus subtilis spores, and they were compared with two kinds of intermediate-level disinfectants, i.e., 7% povidone-iodine (ISODINE) and ethanol for disinfection (76.9-81.4 vol %). Each solution of distilled KMT reagent up to a dilution of 1:100 showed potent bactericidal activity against most tested bacteria when used for 30 seconds at 20 degrees C. Bactericidal activities at these dilutions were almost comparable with those of the same dilution of ISODINE. Although the 1:10 dilution of ISODINE did not show comparable sporicidal activity, the same dilution of distilled KMT reagent showed potent sporicidal activity. On the other hand, the 1:2 dilution of distilled ethanol reagent showed potent sporicidal activity when used for 5 minutes at 60 degrees C. Ethanol for disinfection did not show any sporicidal activity even with treatment for 60 minutes at 60 degrees C. With treatment for 30 sec at 37 degrees C, the 1:2 dilution of distilled ethanol reagent was found to have effective bactericidal activity almost comparable with that of ethanol for disinfection. Appropriate dilutions of both the distilled KMT reagent and distilled ethanol reagent may be applicable as antiseptics which are able to achieve high-level disinfection.

  14. Morphology-dependent bactericidal activities of Ag/CeO2 catalysts against Escherichia coli.

    PubMed

    Wang, Lian; He, Hong; Yu, Yunbo; Sun, Li; Liu, Sijin; Zhang, Changbin; He, Lian

    2014-06-01

    Silver-loaded CeO2 nanomaterials (Ag/CeO2) including Ag/CeO2 nanorods, nanocubes, nanoparticles were prepared with hydrothermal and impregnation methods. Catalytic inactivation of Escherichia coli with Ag/CeO2 catalysts through the formation of reactive oxygen species (ROS) was investigated. For comparison purposes, the bactericidal activities of CeO2 nanorods, nanocubes and nanoparticles were also studied. There was a 3-4 log order improvement in the inactivation of E. coli with Ag/CeO2 catalysts compared with CeO2 catalysts. Temperature-programmed reduction of H2 showed that Ag/CeO2 catalysts had higher catalytic oxidation ability than CeO2 catalysts, which was the reason for that Ag/CeO2 catalysts exhibited stronger bactericidal activities than CeO2 catalysts. Further, the bactericidal activities of CeO2 and Ag/CeO2 depend on their shapes. Results of 5,5-dimethyl-1-pyrroline-N-oxide spin-trapping measurements by electron spin resonance and addition of catalase as a scavenger indicated the formation of OH, O2(-), and H2O2, which caused the obvious bactericidal activity of catalysts. The stronger chemical bond between Ag and CeO2 nanorods led to lower Ag(+) elution concentrations. The toxicity of Ag(+) eluted from the catalysts did not play an important role during the bactericidal process. Experimental results also indicated that Ag/CeO2 induced the production of intracellular ROS and disruption of the cell wall and cell membrane. A possible production mechanism of ROS and bactericidal mechanism of catalytic oxidation were proposed.

  15. The nature of inherent bactericidal activity: insights from the nanotopology of three species of dragonfly

    NASA Astrophysics Data System (ADS)

    Mainwaring, David E.; Nguyen, Song Ha; Webb, Hayden; Jakubov, Timur; Tobin, Mark; Lamb, Robert N.; Wu, Alex H.-F.; Marchant, Richard; Crawford, Russell J.; Ivanova, Elena P.

    2016-03-01

    While insect wings are widely recognised as multi-functional, recent work showed that this extends to extensive bactericidal activity brought about by cell deformation and lysis on the wing nanotopology. We now quantitatively show that subtle changes to this topography result in substantial changes in bactericidal activity that are able to span an order of magnitude. Notably, the chemical composition of the lipid nanopillars was seen by XPS and synchrotron FTIR microspectroscopy to be similar across these activity differences. Modelling the interaction between bacterial cells and the wing surface lipids of 3 species of dragonflies, that inhabit similar environments, but with distinctly different behavioural repertoires, provided the relationship between surface structure and antibacterial functionality. In doing so, these principal behavioural patterns correlated with the demands for antimicrobial efficiency dictated by differences in their foraging strategies. This work now reveals a new feature in the design elegance of natural multi-functional surfaces as well providing insights into the bactericidal mechanism underlying inherently antimicrobial materials, while suggesting that nanotopology is related to the evolutionary development of a species through the demands of its behavioural repertoire. The underlying relationship between the processes of wetting, adhesion and capillarity of the lipid nanopillars and bactericidal efficiency suggests new prospects for purely mechano-responsive antibacterial surfaces.While insect wings are widely recognised as multi-functional, recent work showed that this extends to extensive bactericidal activity brought about by cell deformation and lysis on the wing nanotopology. We now quantitatively show that subtle changes to this topography result in substantial changes in bactericidal activity that are able to span an order of magnitude. Notably, the chemical composition of the lipid nanopillars was seen by XPS and synchrotron

  16. Activation of the neutrophil bactericidal activity for nontypable Haemophilus influenzae by tumor necrosis factor and lymphotoxin.

    PubMed

    Tan, A M; Ferrante, A; Goh, D H; Roberton, D M; Cripps, A W

    1995-02-01

    Previous studies have suggested that, in vivo, activated T lymphocytes and neutrophils are important in immunity to nontypable Haemophilus influenzae. We now extend this work by showing that neutrophils pretreated with products of activated T lymphocytes or activated macrophages show significantly enhanced killing of nontypable H. influenzae. Lymphotoxin, a product of activated T lymphocytes, significantly enhanced the neutrophil-mediated killing of nontypable H. influenzae, and tumor necrosis factor, produced by activated T lymphocytes as well as macrophages stimulated by activated T lymphocytes, also significantly increased the bactericidal activity of neutrophils. These cytokine-induced effects were seen with short pretreatment times of neutrophils and were maximal by 30 min. The killing of H. influenzae by neutrophils required the presence of heat-labile opsonins. In the absence of these opsonins, both tumor necrosis factor and lymphotoxin were unable to promote the killing of the bacteria by neutrophils. Furthermore, the results showed that tumor necrosis factor-primed neutrophils displayed significantly increased expression of CR3 and CR4 that was associated with increased phagocytosis of complement-opsonized nontypable H. influenzae. These cytokines may play an important role in immunity toward nontypable H. influenzae by stimulating neutrophil bactericidal activity.

  17. A complex of equine lysozyme and oleic acid with bactericidal activity against Streptococcus pneumoniae.

    PubMed

    Clementi, Emily A; Wilhelm, Kristina R; Schleucher, Jürgen; Morozova-Roche, Ludmilla A; Hakansson, Anders P

    2013-01-01

    HAMLET and ELOA are complexes consisting of oleic acid and two homologous, yet functionally different, proteins with cytotoxic activities against mammalian cells, with HAMLET showing higher tumor cells specificity, possibly due to the difference in propensity for oleic acid binding, as HAMLET binds 5-8 oleic acid molecules per protein molecule and ELOA binds 11-48 oleic acids. HAMLET has been shown to possess bactericidal activity against a number of bacterial species, particularly those with a respiratory tropism, with Streptococcus pneumoniae displaying the greatest degree of sensitivity. We show here that ELOA also displays bactericidal activity against pneumococci, which at lower concentrations shows mechanistic similarities to HAMLET's bactericidal activity. ELOA binds to S. pneumoniae and causes perturbations of the plasma membrane, including depolarization and subsequent rupture, and activates an influx of calcium into the cells. Selective inhibition of calcium channels and sodium/calcium exchange activity significantly diminished ELOA's bactericidal activity, similar to what we have observed with HAMLET. Finally, ELOA-induced death was also accompanied by DNA fragmentation into high molecular weight fragments - an apoptosis-like morphological phenotype that is seen during HAMLET-induced death. Thus, in contrast to different mechanisms of eukaryote cell death induced by ELOA and HAMLET, these complexes are characterized by rather similar activities towards bacteria. Although the majority of these events could be mimicked using oleic acid alone, the concentrations of oleic acid required were significantly higher than those present in the ELOA complex, and for some assays, the results were not identical between oleic acid alone and the ELOA complex. This indicates that the lipid, as a common denominator in both complexes, is an important component for the complexes' bactericidal activities, while the proteins are required both to solubilize and/or present the

  18. Synergistic bactericidal activity of Ag-TiO₂ nanoparticles in both light and dark conditions.

    PubMed

    Li, Minghua; Noriega-Trevino, Maria Eugenia; Nino-Martinez, Nereyda; Marambio-Jones, Catalina; Wang, Jinwen; Damoiseaux, Robert; Ruiz, Facundo; Hoek, Eric M V

    2011-10-15

    High-throughput screening was employed to evaluate bactericidal activities of hybrid Ag-TiO₂ nanoparticles comprising variations in TiO₂ crystalline phase, Ag content, and synthesis method. Hybrid Ag-TiO₂ nanoparticles were prepared by either wet-impregnation or UV photo deposition onto both Degussa P25 and DuPont R902 TiO₂ nanoparticles. The presence of Ag was confirmed by ICP, TEM, and XRD analysis. The size of Ag nanoparticles formed on anatase/rutile P25 TiO₂ nanoparticles was smaller than those formed on pure rutile R902. When activated by UV light, all hybrid Ag-TiO₂ nanoparticles exhibited stronger bactericidal activity than UV alone, Ag/UV, or UV/TiO₂. For experiments conducted in the dark, bactericidal activity of Ag-TiO₂ nanoparticles was greater than either bare TiO₂ (inert) or pure Ag nanoparticles, suggesting that the hybrid materials produced a synergistic antibacterial effect unrelated to photoactivity. Moreover, less Ag(+) dissolved from Ag-TiO₂ nanoparticles than from Ag nanoparticles, indicating the antibacterial activities of Ag-TiO₂ was not only caused by releasing of toxic metal ions. It is clear that nanotechnology can produce more effective bactericides; however, the challenge remains to identify practical ways to take advantage of these exciting new material properties.

  19. Peroxiredoxin-3 Is Involved in Bactericidal Activity through the Regulation of Mitochondrial Reactive Oxygen Species

    PubMed Central

    Lee, Sena; Wi, Sae Mi; Min, Yoon

    2016-01-01

    Peroxiredoxin-3 (Prdx3) is a mitochondrial protein of the thioredoxin family of antioxidant peroxidases and is the principal peroxidase responsible for metabolizing mitochondrial hydrogen peroxide. Recent reports have shown that mitochondrial reactive oxygen species (mROS) contribute to macrophage-mediated bactericidal activity in response to Toll-like receptors. Herein, we investigated the functional effect of Prdx3 in bactericidal activity. The mitochondrial localization of Prdx3 in HEK293T cells was confirmed by cell fractionation and confocal microscopy analyses. To investigate the functional role of Prdx3 in bactericidal activity, Prdx3-knockdown (Prdx3KD) THP-1 cells were generated. The mROS levels in Prdx3KD THP-1 cells were significantly higher than those in control THP-1 cells. Moreover, the mROS levels were markedly increased in response to lipopolysaccharide. Notably, the Salmonella enterica serovar Typhimurium infection assay revealed that the Prdx3KD THP-1 cells were significantly resistant to S. Typhimurium infection, as compared with control THP-1 cells. Taken together, these results indicate that Prdx3 is functionally important in bactericidal activity through the regulation of mROS. PMID:28035213

  20. In Vitro Bactericidal Activity of the Antiprotozoal Drug Miltefosine against Streptococcus pneumoniae and Other Pathogenic Streptococci▿

    PubMed Central

    Llull, Daniel; Rivas, Luis; García, Ernesto

    2007-01-01

    Miltefosine (hexadecylphosphocholine), the first oral drug against visceral leishmaniasis, triggered pneumococcal autolysis at concentrations higher than 2.5 μM. Bactericidal activity was also observed in cultures of other streptococci, although these failed to undergo lysis. The autolysis elicited by miltefosine can be attributed to triggering of the pneumococcal autolysin LytA. PMID:17353242

  1. The nature of inherent bactericidal activity: insights from the nanotopology of three species of dragonfly.

    PubMed

    Mainwaring, David E; Nguyen, Song Ha; Webb, Hayden; Jakubov, Timur; Tobin, Mark; Lamb, Robert N; Wu, Alex H-F; Marchant, Richard; Crawford, Russell J; Ivanova, Elena P

    2016-03-28

    While insect wings are widely recognised as multi-functional, recent work showed that this extends to extensive bactericidal activity brought about by cell deformation and lysis on the wing nanotopology. We now quantitatively show that subtle changes to this topography result in substantial changes in bactericidal activity that are able to span an order of magnitude. Notably, the chemical composition of the lipid nanopillars was seen by XPS and synchrotron FTIR microspectroscopy to be similar across these activity differences. Modelling the interaction between bacterial cells and the wing surface lipids of 3 species of dragonflies, that inhabit similar environments, but with distinctly different behavioural repertoires, provided the relationship between surface structure and antibacterial functionality. In doing so, these principal behavioural patterns correlated with the demands for antimicrobial efficiency dictated by differences in their foraging strategies. This work now reveals a new feature in the design elegance of natural multi-functional surfaces as well providing insights into the bactericidal mechanism underlying inherently antimicrobial materials, while suggesting that nanotopology is related to the evolutionary development of a species through the demands of its behavioural repertoire. The underlying relationship between the processes of wetting, adhesion and capillarity of the lipid nanopillars and bactericidal efficiency suggests new prospects for purely mechano-responsive antibacterial surfaces.

  2. Sequestration of nanoparticles by an EPS matrix reduces the particle-specific bactericidal activity

    NASA Astrophysics Data System (ADS)

    Wang, Qian; Kang, Fuxing; Gao, Yanzheng; Mao, Xuewei; Hu, Xiaojie

    2016-02-01

    Most artificial nanomaterials are known to exhibit broad-spectrum bactericidal activity; however, the defence mechanisms that bacteria use based on extracellular polymeric substances (EPS) to detoxify nanoparticles (NPs) are not well known. We ruled out the possibility of ion-specific bactericidal activity by showing the lack of equivalent dissolved zinc and silicon toxicity and determined the particle-specific toxicity of ZnO and SiO2 nanoparticles (ZnONPs/SiO2NPs) through dialysis isolation experiments. Surprisingly, the manipulation of the E. coli EPS (i.e., no EPS manipulation or EPS removal by sonication/centrifugation) showed that their particle-specific bactericidal activity could be antagonized by NP-EPS sequestration. The survival rates of pristine E. coli (no EPS manipulation) reached 65% (ZnONPs, 500 mg L‑1) and 79% (SiO2NPs, 500 mg L‑1), whereas survival rates following EPS removal by sonication/centrifugation were 11% and 63%, respectively. Transmission electron microscopy (TEM) combined with fluorescence micro-titration analysis and Fourier-transform infrared spectroscopy (FTIR) showed that protein-like substances (N-H and C-N in amide II) and secondary carbonyl groups (C=O) in the carboxylic acids of EPS acted as important binding sites that were involved in NP sequestration. Accordingly, the amount and composition of EPS produced by bacteria have important implications for the bactericidal efficacy and potential environmental effects of NPs.

  3. Sequestration of nanoparticles by an EPS matrix reduces the particle-specific bactericidal activity

    PubMed Central

    Wang, Qian; Kang, Fuxing; Gao, Yanzheng; Mao, Xuewei; Hu, Xiaojie

    2016-01-01

    Most artificial nanomaterials are known to exhibit broad-spectrum bactericidal activity; however, the defence mechanisms that bacteria use based on extracellular polymeric substances (EPS) to detoxify nanoparticles (NPs) are not well known. We ruled out the possibility of ion-specific bactericidal activity by showing the lack of equivalent dissolved zinc and silicon toxicity and determined the particle-specific toxicity of ZnO and SiO2 nanoparticles (ZnONPs/SiO2NPs) through dialysis isolation experiments. Surprisingly, the manipulation of the E. coli EPS (i.e., no EPS manipulation or EPS removal by sonication/centrifugation) showed that their particle-specific bactericidal activity could be antagonized by NP-EPS sequestration. The survival rates of pristine E. coli (no EPS manipulation) reached 65% (ZnONPs, 500 mg L−1) and 79% (SiO2NPs, 500 mg L−1), whereas survival rates following EPS removal by sonication/centrifugation were 11% and 63%, respectively. Transmission electron microscopy (TEM) combined with fluorescence micro-titration analysis and Fourier-transform infrared spectroscopy (FTIR) showed that protein-like substances (N-H and C-N in amide II) and secondary carbonyl groups (C=O) in the carboxylic acids of EPS acted as important binding sites that were involved in NP sequestration. Accordingly, the amount and composition of EPS produced by bacteria have important implications for the bactericidal efficacy and potential environmental effects of NPs. PMID:26856606

  4. Bacteriostatic and bactericidal activities of 24 antimicrobial agents against Campylobacter fetus subsp. jejuni.

    PubMed

    Vanhoof, R; Gordts, B; Dierickx, R; Coignau, H; Butzler, J P

    1980-07-01

    The bacteriostatic and bactericidal activities of 24 antimicrobial agents were tested with the Dynatech MIC 2000 system against 86 strains of Campylobacter fetus subsp. jejuni from human sources. The penicillins (penicillin G, ampicillin, amoxycillin, carbenicillin) had poor activity. Ampicillin and amoxycillin were equally active. Cefotaxime revealed a rather good activity. Erythromycin, gentamicin, tobramycin, amikacin, and furazolidone were the most active compounds. Two strains (2.3%) were resistant to erythromycin. One strain (1.2%) was completely resistant to tobramycin. The tetracyclines (tetracyline, doxycycline, minocycline) were generally effective, but 8% of the strains were totally resistant to them. Minocycline was the most active. Chloramphenicol, thiamphenicol, and clindamycin had good activity. The bacteriostatic and bactericidal distributions for colistin, nalidixic acid, and metronidazole were broad.

  5. The effect of trypsin and chymotrypsin on the bactericidal activity and specific antibody activity of bovine colostrum.

    PubMed Central

    Brock, J H; Arzabe, R; Piñeiro, A; Olivito, A M

    1977-01-01

    Digestion of bovine colostral whey with trypsin or chymotrypsin caused a progressive loss of the complement-mediated bactericidal activity of naturally-occurring colostral antibodies of E. coli 0111. Bactericidal activity was associated primarily with IgG1 immunoglobulin and to a lesser extent with IgM. Chymotrypsin preferentially attacked IgM, destroying its antibacterial activity and producing an apparent decrease in its mol wt. Trypsin preferentially attacked IgG1, but loss of antibacterial activity was in this case not accompanied by a decrease in molecular weight. Using colostral whey with antiperoxidase activity it was shown that the kinetics of loss of specific antibody activity were similar to those of loss of bactericidal activity. It is therefore suggested that trypsin may cause a loss of specific antibody activity of colostral IgG1 without cleaving the immunoglobulin molecule. PMID:321342

  6. Bactericidal activity of multiple combinations of tigecycline and colistin against NDM-1-producing Enterobacteriaceae.

    PubMed

    Albur, Mahableshwar; Noel, Alan; Bowker, Karen; MacGowan, Alasdair

    2012-06-01

    The interaction between colistin and tigecycline against eight well-characterized NDM-1-producing Enterobacteriaceae strains was studied. Time-kill methodology was employed using a 4-by-4 exposure matrix with pharmacokinetically achievable free drug peak, trough, and average 24-h serum concentrations. Colistin sulfate and methanesulfonate alone showed good early bactericidal activity, often with subsequent regrowth. Tigecycline alone had poor activity. Addition of tigecycline to colistin does not produce increased bacterial killing; instead, it may cause antagonism at lower concentrations.

  7. Evaluation of bactericidal activity of weakly acidic electrolyzed water (WAEW) against Vibrio vulnificus and Vibrio parahaemolyticus.

    PubMed

    Quan, Yaru; Choi, Kyoo-Duck; Chung, Donghwa; Shin, Il-Shik

    2010-01-01

    Vibrio parahaemolyticus and Vibriovulnificus cause severe foodborne illness in humans; thus, to reduce outbreaks of disease, it is clearly important to reduce food contamination by these pathogens. Although electrolyzed oxidizing (EO) water has been reported to exhibit strong bactericidal activities against many pathogens, it has never been tested against V. vulnificus and V. parahaemolyticus. The purpose of this study was to evaluate the bactericidal activity of weakly acidic electrolyzed water (WAEW), a type of EO water, against V. vulnificus and V. parahaemolyticus. Cell suspensions and cell cultures of both pathogens were treated for 30s with sodium hypochlorite solution containing 35mg/L available chlorine concentration (ACC) or WAEW containing 35mg/L ACC. After an initial inoculum of 5.7logCFU/mL, the number of viable V. vulnificus cells was reduced by 2.2 logs after treatment for 60s with sodium hypochlorite solution containing 35mg/L ACC, while no cells survived treatment with WAEW for 30s. Similar results were obtained for V. parahaemolyticus. Under open storage conditions, WAEW maintained bactericidal activities against cell suspensions of both strains after 5weeks but disappeared against cell cultures of the two strains after 5weeks. Under closed storage conditions, however, WAEW maintained bactericidal activities against both cell suspensions and cell cultures of each strain after 5weeks. No cells were detected in the cell suspensions and cultures when the ACC of WAEW was more than 20mg/L and treatment time was greater than 15s. Bactericidal activity of WAEW against V. vulnificus cell culture was reduced when the ACC of WAEW was less than 15mg/L but was maintained in the V. vulnificus cell suspension when the ACC of WAEW was 0.5mg/L. Thus, the bactericidal activity of WAEW was primarily affected by ACC rather than treatment time. Similar results were obtained for V. parahaemolyticus, indicating that WAEW kills these microorganisms more quickly than a

  8. Inhibition of bactericidal activity by pentachlorophenol in two phagocyte populations from Fundulus heteroclitus

    SciTech Connect

    Roszell, L.E.; Anderson, R.S.

    1994-12-31

    The effects of pentachlorophenol (PCP) on the bactericidal activity of pronephritic phagocytes were studied in an estuarine fish, Fundulus heteroclitus. Following in vitro exposure to sublethal doses of PCP, macrophages and eosinophils were challenged with Listonella anguillarum, the bacterium responsible for vibriosis in marine and freshwater fish. Quantification of surviving bacteria was based on the reduction of MTT (3-[4,5 dimethylthiazol-2-yl]-2,5-diphenyl-tetrazolium bromide). Bacteridical activity was inhibited at PCP concentrations greater than 5 ppm in both leukocyte populations; at 20 ppm bactericidal activity was essentially eliminated. The primary cellular mechanisms of bactericidal activity in these cells are phagocytosis and the phagocytically induced production of reactive oxygen intermediates (ROIs) including superoxide (O{sub 2}{sup {minus}}) and hydrogen peroxide (H{sub 2}O{sub 2}). Previous experiments have shown that these activities are inhibited at similar concentrations of PCP. These results indicate that the suppression of phagocytosis and the subsequent oxidative burst is responsible for the reduced killing seen in the current experiments. Nonspecific immune activities of phagocytic cells such as macrophages and eosinophils act as a first line of defense against invading pathogens; the suppression of these functions could ultimately lead to decreased resistance to infectious disease.

  9. Bactericidal activity of propylene glycol, glycerine, polyethylene glycol 400, and polyethylene glycol 1000 against selected microorganisms

    PubMed Central

    Nalawade, Triveni Mohan; Bhat, Kishore; Sogi, Suma H. P.

    2015-01-01

    Aim: The aim of the present study was to evaluate the bactericidal activity of propylene glycol, glycerine, polyethylene glycol 400 (PEG 400), and polyethylene glycol 1000 (PEG 1000) against selected microorganisms in vitro. Materials and Methods: Five vehicles, namely propylene glycol, glycerine, PEG 400, PEG 1000, and combination of propylene glycol with PEG 400, were tested for their bactericidal activity. The minimum bactericidal concentration was noted against four standard strains of organisms, i.e. Streptococcus mutans American Type Culture Collection (ATCC) 25175, Streptococcus mutans ATCC 12598, Enterococcus faecalis ATCC 35550, and Escherichia coli ATCC 25922, using broth dilution assay. Successful endodontic therapy depends upon thorough disinfection of root canals. In some refractory cases, routine endodontic therapy is not sufficient, so intracanal medicaments are used for proper disinfection of canals. Intracanal medicaments are dispensed with vehicles which aid in increased diffusion through the dentinal tubules and improve their efficacy. Among the various vehicles used, glycerine is easily available, whereas others like propylene glycol and polyethylene glycol have to be procured from appropriate sources. Also, these vehicles, being viscous, aid in sustained release of the medicaments and improve their handling properties. The most commonly used intracanal medicaments like calcium hydroxide are ineffective on many microorganisms, while most of the other medicaments like MTAD (Mixture of Tetracycline, an Acid, and a Detergent) and Triple Antibiotic Paste (TAP) consist of antibiotics which can lead to development of antibiotic resistance among microorganisms. Thus, in order to use safer and equally effective intracanal medicaments, newer alternatives like chlorhexidine gluconate, ozonized water, etc., are being explored. Similarly, the five vehicles mentioned above are being tested for their antimicrobial activity in this study. Results: All vehicles

  10. Serum bactericidal activity in a secondary school population following an outbreak of meningococcal disease: effects of carriage and secretor status.

    PubMed

    Zorgani, A A; James, V S; Stewart, J; Blackwell, C C; Elton, R A; Weir, D M

    1996-06-01

    Sera obtained from 106 children following an outbreak of Neisseria meningitidis (B:4:P1.15) were screened for bactericidal antibodies against isolates of meningococci and Neisseria lactamica. Most had high titres of antibodies to N. lactamica and N. meningitidis NG:4:- but not to capsulate isolates: B:4:P1.15; B:15:P1.16; B:4:-; C:4:-. Bactericidal activity was higher for both carriers and secretors but the differences were not significant. Bactericidal activity was not associated with total or specific IgA or IgM. Carriers had significantly higher levels of IgG to N. lactamica but not to NG:4:- in sera with bactericidal activity for each of the capsulate strains. Among non-carriers, higher levels of IgG to N. lactamica were associated with killing of B:4:P1.15 and B:4:-. Secretors' sera with bactericidal activity had significantly higher levels of IgG to N. lactamica compared with sera that were not bactericidal. This was not observed among non-secretors. Antibodies to the outbreak strain were adsorbed by all Neisseria isolates tested and absorption of sera with N. lactamica alone completely removed the bactericidal activity against the outbreak strain.

  11. Determination of tolerance to antibiotic bactericidal activity on Kirby-Bauer susceptibility plates.

    PubMed

    Peterson, L R; Denny, A E; Gerding, D N; Hall, W H

    1980-11-01

    A rapid method utilizing Kirby-Bauer susceptibility plates was developed to determine bacterial tolerance to antibiotic bactericidal activity. After completion of initial antibiotic disk susceptibility testing, the disks containing cephalothin, cefazolin, nafcillin, oxacillin, and methicillin were removed and replaced with disks containing a potent beta-lactamase. The plates were reincubated for 18-24 hours and examined for regrowth of organisms within the original zone of inhibition. For 15 of 16 patients who had serious Staphylococcus aureus infections, the method correlated with clinical outcome of antibiotic chemotherapy. Broth dilution tests for bactericidal activity only correlated with clinical response for 11 of 16 patients. One hundred consecutive clinical S. aureus isolates tested with the new method demonstrated tolerance in 27% of strains to cephalothin, 15% to cefazolin, 1% to oxacillin, and 2% of nafcillin.

  12. The effect of the bacterial product, succinic acid, on neutrophil bactericidal activity.

    PubMed

    Abdul-Majid, K B; Kenny, P A; Finlay-Jones, J J

    1997-02-01

    We investigated the effect of succinic acid on neutrophil bactericidal activity in a model of intra-abdominal abscess induced in mice by the peritoneal inoculation of 5 x 10(6) cfu ml-1 E. coli and 5 x 10(8) cfu ml-1 B. fragilis plus 1 mg of bran as faecal fibre analogue. The mean pH of the induced abscesses at week 1 was 6.7, higher than the pH associated with succinic acid inhibitory activity. We therefore determined the effect of succinic acid (0-100 mM) at pH 6.7 on the bactericidal activity of mouse bone marrow-derived neutrophils. Phagocytic killing of Proteus mirabilis by neutrophils was significantly inhibited by 30-100 mM succinic acid at pH 6.7 but there was no significant effect of succinic acid on engulfment of bacteria at this pH. However, significant inhibition of intracellular killing (assayed by adding succinic acid to suspensions of neutrophils which had engulfed bacteria in low serum concentrations but in the absence of succinic acid) was noted at 70 and 100 mM. These results indicate that succinic acid inhibits neutrophil bactericidal activity at a physiological pH, principally through inhibition of intracellular killing mechanisms and therefore contributing to bacterial persistence in this model of abscess formation.

  13. Bactericidal and sterilizing activities of several orally administered combined regimens against Mycobacterium ulcerans in mice.

    PubMed

    Ji, Baohong; Chauffour, Aurélie; Robert, Jérome; Jarlier, Vincent

    2008-06-01

    Treatment with rifampin-clarithromycin or moxifloxacin-clarithromycin for 8 weeks displayed promising bactericidal activity against Mycobacterium ulcerans in mice; none of the mice treated with rifampin-clarithromycin relapsed, whereas 59% of those treated with moxifloxacin-clarithromycin relapsed after treatment was stopped. The bactericidal and sterilizing activities of the five-times-weekly (5/7) administration of 5 mg of rifapentine/kg of body weight, either alone or in combination, were virtually identical to those of the corresponding regimens with 10 mg of rifampin/kg of body weight; however, because of the long half-life of rifapentine, accumulation of the drug after 5/7 administration is a concern. The bactericidal activity of 20 mg/kg rifapentine in monotherapy or 20 mg/kg rifapentine in combination with 150 mg/kg streptomycin or 200 mg/kg moxifloxacin administered twice weekly was as effective as the corresponding regimens containing 10 mg/kg rifampin administered 5/7, suggesting that Buruli ulcer might be treated with intermittently administered rifapentine-containing combinations.

  14. Comparative serum bactericidal activities of three doses of ciprofloxacin administered intravenously.

    PubMed Central

    Dan, M; Poch, F; Quassem, C; Kitzes, R

    1994-01-01

    The pharmacokinetics and serum bactericidal activities of three intravenous doses of ciprofloxacin were studied comparatively in 30 patients. Single 200-, 300-, and 400-mg intravenous doses of ciprofloxacin were given over 30 min to 10 patients each, and serum samples were obtained at 0.5, 1, 2, 3, 4, 8, and 12 h after the start of the infusion. Serum drug concentrations were determined by high-pressure liquid chromatography. Pharmacokinetic parameters were estimated by using noncompartmental analysis methods. Serum bactericidal activity against clinical isolates of Escherichia coli, Enterobacter cloacae, Pseudomonas aeruginosa, Acinetobacter calcoaceticus, and Staphylococcus aureus was determined for samples obtained at 0.5, 4, 8, and 12 h. Excellent activity was demonstrated up to 12 h by all doses against E. coli and E. cloacae. Much poorer titers were observed for the remaining organisms, although the 400-mg dose prompted improved results against P. aeruginosa with a mean bactericidal titer of 1:2.9 at 8 h. In conclusion, while the 200-mg dose appears to be largely adequate for infections caused by members of the family Enterobacteriaceae, it seems that when P. aeruginosa is involved, 400 mg twice a day or even three times a day is more appropriate. Intravenous ciprofloxacin performs poorly against A. calcoaceticus and S. aureus, even at a higher dose. PMID:8031055

  15. Involvement of nitric oxide donor compounds in the bactericidal activity of human neutrophils in vitro.

    PubMed

    Klink, Magdalena; Cedzyński, Maciej; St Swierzko, Anna; Tchórzewski, Henryk; Sulowska, Zofia

    2003-04-01

    The bactericidal activity of human neutrophils against extracellular and facultatively intracellular bacteria was studied in the presence of the nitric oxide (NO) donors sodium nitroprusside (SNP) and 3-morpholinosydnonimine (SIN-1), a molsidomine metabolite. SNP and molsidomine are drugs commonly used as nitrovasodilators in coronary heart disease. It is demonstrated here that the NO donor compounds themselves did not affect the viability and survival of the bacterial strains tested. Neither SNP nor SIN-1 had any effect on the process of bacteria ingestion. In contrast, NO donors enhanced the ability of neutrophils to kill Escherichia coli, Proteus vulgaris and Salmonella Anatum. However, strains differed in their susceptibility to SNP- and SIN-1-mediated killing by neutrophils. Removal of the superoxide anion reduced the bactericidal activity of SNP- and SIN-1-treated neutrophils against E. coli and S. Anatum. This suggests that the NO derivatives formed in the reaction of NO generated from donors with the reactive oxygen species released by phagocytosed neutrophils potentiate the bactericidal activity of human neutrophils in vitro. The above original observation discussed here suggests clinical significance for the treatment of patients with nitrovasodilators in the course of coronary heart disease therapy.

  16. Bactericidal Activity and Mechanism of Photoirradiated Polyphenols against Gram-Positive and -Negative Bacteria.

    PubMed

    Nakamura, Keisuke; Ishiyama, Kirika; Sheng, Hong; Ikai, Hiroyo; Kanno, Taro; Niwano, Yoshimi

    2015-09-09

    The bactericidal effect of various types of photoirradiated polyphenols against Gram-positive and -negative bacteria was evaluated in relation to the mode of action. Gram-positive bacteria (Enterococcus faecalis, Staphylococcus aureus, and Streptococcus mutans) and Gram-negative bacteria (Aggregatibacter actinomycetemcomitans, Escherichia coli, and Pseudomonas aeruginosa) suspended in a 1 mg/mL polyphenol aqueous solution (caffeic acid, gallic acid, chlorogenic acid, epigallocatechin, epigallocatechin gallate, and proanthocyanidin) were exposed to LED light (wavelength, 400 nm; irradiance, 260 mW/cm(2)) for 5 or 10 min. Caffeic acid and chlorogenic acid exerted the highest bactericidal activity followed by gallic acid and proanthocyanidin against both Gram-positive and -negative bacteria. It was also demonstrated that the disinfection treatment induced oxidative damage of bacterial DNA, which suggests that polyphenols are incorporated into bacterial cells. The present study suggests that blue light irradiation of polyphenols could be a novel disinfection treatment.

  17. Bactericidal and synergistic activity of moxalactam alone and in combination with gentamicin against Pseudomonas aeruginosa.

    PubMed Central

    Yu, P K; Edson, R S; Washington, J A; Hermans, P E

    1983-01-01

    The bactericidal activity of moxalactam, alone and in combination with gentamicin, was studied with macrobroth two-dimensional checkerboard and killing curve techniques against gentamicin-resistant and -susceptible strains of Pseudomonas aeruginosa. Moxalactam was bactericidal at concentrations equal to or at least two to four times its inhibitory concentrations. Synergy at clinically applicable concentrations of moxalactam and gentamicin occurred with 6 of 14 gentamicin-resistant strains and 4 of 4 gentamicin-susceptible strains by the checkerboard technique and with 7 of 14 gentamicin-resistant strains by the killing curve technique. Synergy between moxalactam and gentamicin against gentamicin-resistant strains of P. aeruginosa is unpredictable and strain- and method-dependent. PMID:6219619

  18. Selective bactericidal activity of nanopatterned superhydrophobic cicada Psaltoda claripennis wing surfaces.

    PubMed

    Hasan, Jafar; Webb, Hayden K; Truong, Vi Khanh; Pogodin, Sergey; Baulin, Vladimir A; Watson, Gregory S; Watson, Jolanta A; Crawford, Russell J; Ivanova, Elena P

    2013-10-01

    The nanopattern on the surface of Clanger cicada (Psaltoda claripennis) wings represents the first example of a new class of biomaterials that can kill bacteria on contact based solely on its physical surface structure. As such, they provide a model for the development of novel functional surfaces that possess an increased resistance to bacterial contamination and infection. Their effectiveness against a wide spectrum of bacteria, however, is yet to be established. Here, the bactericidal properties of the wings were tested against several bacterial species, possessing a range of combinations of morphology and cell wall type. The tested species were primarily pathogens, and included Bacillus subtilis, Branhamella catarrhalis, Escherichia coli, Planococcus maritimus, Pseudomonas aeruginosa, Pseudomonas fluorescens, and Staphylococcus aureus. The wings were found to consistently kill Gram-negative cells (i.e., B. catarrhalis, E. coli, P. aeruginosa, and P. fluorescens), while Gram-positive cells (B. subtilis, P. maritimus, and S. aureus) remained resistant. The morphology of the cells did not appear to play any role in determining cell susceptibility. The bactericidal activity of the wing was also found to be quite efficient; 6.1 ± 1.5 × 10(6) P. aeruginosa cells in suspension were inactivated per square centimeter of wing surface after 30-min incubation. These findings demonstrate the potential for the development of selective bactericidal surfaces incorporating cicada wing nanopatterns into the design.

  19. Human Salivary Protein Histatin 5 Has Potent Bactericidal Activity against ESKAPE Pathogens

    PubMed Central

    Du, Han; Puri, Sumant; McCall, Andrew; Norris, Hannah L.; Russo, Thomas; Edgerton, Mira

    2017-01-01

    ESKAPE (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumanni, Pseudomonas aeruginosa, and Enterobacter species) pathogens have characteristic multiple-drug resistance and cause an increasing number of nosocomial infections worldwide. Peptide-based therapeutics to treat ESKAPE infections might be an alternative to conventional antibiotics. Histatin 5 (Hst 5) is a salivary cationic histidine-rich peptide produced only in humans and higher primates. It has high antifungal activity against Candida albicans through an energy-dependent, non-lytic process; but its bactericidal effects are less known. We found Hst 5 has bactericidal activity against S. aureus (60–70% killing) and A. baumannii (85–90% killing) in 10 and 100 mM sodium phosphate buffer (NaPB), while killing of >99% of P. aeruginosa, 60–80% E. cloacae and 20–60% of E. faecium was found in 10 mM NaPB. Hst 5 killed 60% of biofilm cells of P. aeruginosa, but had reduced activity against biofilms of S. aureus and A. baumannii. Hst 5 killed 20% of K. pneumonia biofilm cells but not planktonic cells. Binding and uptake studies using FITC-labeled Hst 5 showed E. faecium and E. cloacae killing required Hst 5 internalization and was energy dependent, while bactericidal activity was rapid against P. aeruginosa and A. baumannii suggesting membrane disruption. Hst 5-mediated killing of S. aureus was both non-lytic and energy independent. Additionally, we found that spermidine conjugated Hst 5 (Hst5-Spd) had improved killing activity against E. faecium, E. cloacae, and A. baumannii. Hst 5 or its derivative has antibacterial activity against five out of six ESKAPE pathogens and may be an alternative treatment for these infections. PMID:28261570

  20. Bactericidal Effects against S. aureus and Physicochemical Properties of Plasma Activated Water stored at different temperatures

    PubMed Central

    Shen, Jin; Tian, Ying; Li, Yinglong; Ma, Ruonan; Zhang, Qian; Zhang, Jue; Fang, Jing

    2016-01-01

    Water activated by non-thermal plasma creates an acidified solution containing reactive oxygen and nitrogen species, known as plasma-activated water (PAW). The objective of this study was to investigate the effects of different storage temperatures (25 °C, 4 °C, −20 °C, −80 °C) on bactericidal activities against S. aureus and physicochemical properties of PAW up to 30 days. Interestingly, PAW stored at −80 °C yielded the best antibacterial activity against Staphylococcus aureus, 3~4 log reduction over a 30-day period after PAW generation; meanwhile, PAW stored at 25 °C, 4 °C, and −20 °C, respectively, yielded 0.2~2 log decrease in cell viability after the same exposure and storage time. These results were verified by scanning electron microscope (SEM). The physicochemical properties of PAW stored at different temperatures were evaluated, including pH, oxidation reduction potential (ORP), and hydrogen peroxide, nitrate, nitrite anion and NO radical levels. These findings suggested that bacterial activity of PAW stored at 25 °C, 4 °C, −20 °C decreased over time, and depended on three germicidal factors, specifically ORP, H2O2, and NO3−. Moreover, PAW stored at −80 °C retained bactericidal activity, with NO2− contributing to bactericidal ability in association with H2O2. Our findings provide a basis for PAW storage and practical applications in disinfection and food preservation. PMID:27346695

  1. Bactericidal Effects against S. aureus and Physicochemical Properties of Plasma Activated Water stored at different temperatures

    NASA Astrophysics Data System (ADS)

    Shen, Jin; Tian, Ying; Li, Yinglong; Ma, Ruonan; Zhang, Qian; Zhang, Jue; Fang, Jing

    2016-06-01

    Water activated by non-thermal plasma creates an acidified solution containing reactive oxygen and nitrogen species, known as plasma-activated water (PAW). The objective of this study was to investigate the effects of different storage temperatures (25 °C, 4 °C, ‑20 °C, ‑80 °C) on bactericidal activities against S. aureus and physicochemical properties of PAW up to 30 days. Interestingly, PAW stored at ‑80 °C yielded the best antibacterial activity against Staphylococcus aureus, 3~4 log reduction over a 30-day period after PAW generation; meanwhile, PAW stored at 25 °C, 4 °C, and ‑20 °C, respectively, yielded 0.2~2 log decrease in cell viability after the same exposure and storage time. These results were verified by scanning electron microscope (SEM). The physicochemical properties of PAW stored at different temperatures were evaluated, including pH, oxidation reduction potential (ORP), and hydrogen peroxide, nitrate, nitrite anion and NO radical levels. These findings suggested that bacterial activity of PAW stored at 25 °C, 4 °C, ‑20 °C decreased over time, and depended on three germicidal factors, specifically ORP, H2O2, and NO3‑. Moreover, PAW stored at ‑80 °C retained bactericidal activity, with NO2‑ contributing to bactericidal ability in association with H2O2. Our findings provide a basis for PAW storage and practical applications in disinfection and food preservation.

  2. Bactericidal Effects against S. aureus and Physicochemical Properties of Plasma Activated Water stored at different temperatures.

    PubMed

    Shen, Jin; Tian, Ying; Li, Yinglong; Ma, Ruonan; Zhang, Qian; Zhang, Jue; Fang, Jing

    2016-06-27

    Water activated by non-thermal plasma creates an acidified solution containing reactive oxygen and nitrogen species, known as plasma-activated water (PAW). The objective of this study was to investigate the effects of different storage temperatures (25 °C, 4 °C, -20 °C, -80 °C) on bactericidal activities against S. aureus and physicochemical properties of PAW up to 30 days. Interestingly, PAW stored at -80 °C yielded the best antibacterial activity against Staphylococcus aureus, 3~4 log reduction over a 30-day period after PAW generation; meanwhile, PAW stored at 25 °C, 4 °C, and -20 °C, respectively, yielded 0.2~2 log decrease in cell viability after the same exposure and storage time. These results were verified by scanning electron microscope (SEM). The physicochemical properties of PAW stored at different temperatures were evaluated, including pH, oxidation reduction potential (ORP), and hydrogen peroxide, nitrate, nitrite anion and NO radical levels. These findings suggested that bacterial activity of PAW stored at 25 °C, 4 °C, -20 °C decreased over time, and depended on three germicidal factors, specifically ORP, H2O2, and NO3(-). Moreover, PAW stored at -80 °C retained bactericidal activity, with NO2(-) contributing to bactericidal ability in association with H2O2. Our findings provide a basis for PAW storage and practical applications in disinfection and food preservation.

  3. Effects of pollutant exposure on bactericidal activity of Mercenaria mercenaria hemolymph

    SciTech Connect

    Anderson, R.S. )

    1988-09-01

    Exposure of mammals to certain immunotoxic environmental contaminants is most commonly manifested by decreased resistance to infectious agents such as microbes and metazoan parasites. It has been shown that exposed clams showed impaired ability to eliminate an injected dose of normally nonpathogenic bacteria from their hemolymph. This apparent form of immunosuppression seen in vivo could result from induced deficiencies in cellular and/or humoral factors. In this paper, the relative contributions of these mechanisms to reduced bactericidal efficiency are evaluated in vitro, in hemolymph withdrawn from exposed and control clams. Hexachlorobenzene (HCB) and pentachlorophenol (PCP) were used as test pollutants. The effects of PCP or HCB exposure on hemolymph bactericidal activity are summarized. Both high and low PCP doses caused significant inhibition of S. marcescens killing, whereas only the high dose inhibited anti-Flavobacterium activity. The HCB dosing procedure resulted in pollutant body burdens comparable to those seen in the low-dose PCP study; activity against S. marcescens was slightly inhibited, but there was no apparent effect in the case of Flavobacterium. These in vitro assays showed that the bacterial clearance impairment previously observed in pollutant-stressed Mercenaria was probably a result of compromised hemocytic activity.

  4. Increased bactericidal activity of colistin on Pseudomonas aeruginosa biofilms in anaerobic conditions

    PubMed Central

    Kolpen, Mette; Appeldorff, Cecilie F.; Brandt, Sarah; Mousavi, Nabi; Kragh, Kasper N.; Aydogan, Sevtap; Uppal, Haleema A.; Bjarnsholt, Thomas; Ciofu, Oana; Høiby, Niels; Jensen, Peter Ø.

    2015-01-01

    Tolerance towards antibiotics of Pseudomonas aeruginosa biofilms is recognized as a major cause of therapeutic failure of chronic lung infection in cystic fibrosis (CF) patients. This lung infection is characterized by antibiotic-tolerant biofilms in mucus with zones of O2 depletion mainly due to polymorphonuclear leukocytic activity. In contrast to the main types of bactericidal antibiotics, it has not been possible to establish an association between the bactericidal effects of colistin and the production of detectable levels of OH ˙ on several strains of planktonic P. aeruginosa. Therefore, we propose that production of OH ˙ may not contribute significantly to the bactericidal activity of colistin on P. aeruginosa biofilm. Thus, we investigated the effect of colistin treatment on biofilm of wild-type PAO1, a catalase-deficient mutant (ΔkatA) and a colistin-resistant CF isolate cultured in microtiter plates in normoxic- or anoxic atmosphere with 1 mM nitrate. The killing of bacteria during colistin treatment was measured by CFU counts, and the OH⋅ formation was measured by 3′-(p-hydroxylphenyl fluorescein) fluorescein (HPF) fluorescence. Validation of the assay was done by hydrogen peroxide treatment. OH⋅ formation was undetectable in aerobic PAO1 biofilms during 3 h of colistin treatment. Interestingly, we demonstrate increased susceptibility of P. aeruginosa biofilms towards colistin during anaerobic conditions. In fact, the maximum enhancement of killing by anaerobic conditions exceeded 2 logs using 4 mg L−1 of colistin compared to killing at aerobic conditions. PMID:26458402

  5. Crossover assessment of serum bactericidal activity of grepafloxacin, ofloxacin and clarithromycin against respiratory pathogens after oral administration to healthy volunteers.

    PubMed

    Dan, M; Poch, F; Asherov, J

    2001-06-01

    Serum bactericidal activity was studied in a crossover manner in 10 volunteers, after 2-day administration of grepafloxacin 600 mg qd, ofloxacin 400 mg bid and clarithromycin 500 mg bid. Bactericidal activity against clinical isolates of Streptococcus pneumoniae, Haemophilus influenzae, Moraxella catarrhalis and Klebsiella pneumoniae, was estimated using a standardized microdilution method. Grepafloxacin was highly active against Gram-negative organisms and adequate against pneumococci (mean, 1:13.3). Clarithromycin was very active against both penicillin-susceptible and penicillin-partially-resistant S. pneumoniae (1:102.5) but had poor activity against H. influenzae (1:3.1). Minor adverse effects were commonly associated with grepafloxacin.

  6. Modulatory effect of plumbagin (5-hydroxy-2-methyl-1,4-naphthoquinone) on macrophage functions in BALB/c mice. I. Potentiation of macrophage bactericidal activity.

    PubMed

    Abdul, K M; Ramchender, R P

    1995-09-01

    The modulatory ability of plumbagin, a natural product from Plumbago zeylanica, was studied on peritoneal macrophages of BALB/c mice. The macrophage functions evaluated were bactericidal activity, hydrogen peroxide and superoxide anion release. The bactericidal capacity of in vivo plumbagin-treated mouse macrophages was estimated against Staphylococcus aureus. In low doses plumbagin exerted a constant increase in bactericidal activity throughout the study period whereas with a high dose a higher response was observed up to six weeks. But in the next two weeks a considerable decline in the bactericidal activity was noticed compared to low dose. Plumbagin was also seen to exert a similar response on oxygen radical release by macrophages in vivo showing a clear correlation between oxygen radical release and the bactericidal activity. The data indicate that plumbagin augments the macrophage bactericidal activity by potentiating the oxyradical release at low concentration whereas at the higher concentration it has inhibitory activity.

  7. A Kunitz proteinase inhibitor from corms of Xanthosoma blandum with bactericidal activity.

    PubMed

    Lima, Thaís B; Silva, Osmar N; Migliolo, Ludovico; Souza-Filho, Carlos R; Gonçalves, Eduardo G; Vasconcelos, Ilka M; Oliveira, José T A; Amaral, André C; Franco, Octávio L

    2011-05-27

    Bacterial infections directly affect the world's population, and this situation has been aggravated by indiscriminate use of antimicrobial agents, which can generate resistant microorganisms. In this report, an initial screening of proteins with antibacterial activity from corms of 15 species of the Xanthosoma genus was conducted. Since Xanthosoma blandum corms showed enhanced activity toward bacteria, a novel protein with bactericidal activity was isolated from this particular species. Edman degradation was used for protein N-termini determination; the primary structure showed similarities with Kunitz inhibitors, and this protein was named Xb-KTI. This protein was further challenged against serine proteinases from different sources, showing clear inhibitory activities. Otherwise, no hemolytic activity was observed for Xb-KTI. The results demonstrate the biotechnological potential of Xb-KTI, the first proteinase inhibitor with antimicrobial activity described in the Xanthosoma genus.

  8. [Bacteriostatic and bactericidal activities of cyclines, macrolides and fluoroquinolones against Chlamydia trachomatis].

    PubMed

    Dailloux, M; Villemain, P

    1992-05-01

    The in vitro activity of minocycline, doxycycline, erythromycin, roxithromycin, spiramycin, pefloxacin, and ofloxacin against ten C. trachomatis strains recovered from human genital tract specimens was evaluated. Mac Coy cell monolayers in 24-microwell plates were used. The C. trachomatis inoculum was 10(4) IFU/well. Appropriate dilutions of antibiotic were added and inclusions were detected by immunofluorescence using monoclonal antibodies. MICs were determined after 48 hours of exposure to each antimicrobial. The MIC90 for cyclines was 0.2 mg/l. Among tested macrolides, roxithromycin had a lower MIC than erythromycin (0.2 versus 0.4 mg/l) whereas spiramycin inhibited growth only in a concentration of 2 mg/l. Ofloxacin showed better activity than pefloxacin. Bactericidal activity was evaluated by determining two parameters: MBC1 (without transfer to new cells) measured the ability of a C. trachomatis particle to persist in a latent form within cells exposed to an antibiotic and to grow again following removal of the antibiotic, whereas MBC2 (with transfer to new cells) reflected infectivity of the bacteria after 48 hours exposure to the antimicrobial. None of the tested antibiotics was bactericidal according to both parameters. The ability of C. trachomatis to remain within antibiotic-exposed cells in a latent form was clearly demonstrated by the high MBC1 values. This feature may explain why recurrences are common in clinical practice.

  9. Enteric pathogens deploy cell cycle inhibiting factors to block the bactericidal activity of Perforin-2

    PubMed Central

    McCormack, Ryan M; Lyapichev, Kirill; Olsson, Melissa L; Podack, Eckhard R; Munson, George P

    2015-01-01

    Perforin-2 (MPEG1) is an effector of the innate immune system that limits the proliferation and spread of medically relevant Gram-negative, -positive, and acid fast bacteria. We show here that a cullin-RING E3 ubiquitin ligase (CRL) complex containing cullin-1 and βTrCP monoubiquitylates Perforin-2 in response to pathogen associated molecular patterns such as LPS. Ubiquitylation triggers a rapid redistribution of Perforin-2 and is essential for its bactericidal activity. Enteric pathogens such as Yersinia pseudotuberculosis and enteropathogenic Escherichia coli disarm host cells by injecting cell cycle inhibiting factors (Cifs) into mammalian cells to deamidate the ubiquitin-like protein NEDD8. Because CRL activity is dependent upon NEDD8, Cif blocks ubiquitin dependent trafficking of Perforin-2 and thus, its bactericidal activity. Collectively, these studies further underscore the biological significance of Perforin-2 and elucidate critical molecular events that culminate in Perforin-2-dependent killing of both intracellular and extracellular, cell-adherent bacteria. DOI: http://dx.doi.org/10.7554/eLife.06505.001 PMID:26418746

  10. Potential role of autophagy in the bactericidal activity of human PMNs for Bacillus anthracis

    PubMed Central

    Ramachandran, Girish; Gade, Padmaja; Tsai, Pei; Lu, Wuyuan; Kalvakolanu, Dhananjaya V.; Rosen, Gerald M.; Cross, Alan S.

    2015-01-01

    Bacillus anthracis, the causative agent of anthrax, is acquired by mammalian hosts from the environment, as quiescent endospores. These endospores must germinate inside host cells, forming vegetative bacilli, before they can express the virulence factors that enable them to evade host defenses and disseminate throughout the body. While the role of macrophages and dendritic cells in this initial interaction has been established, the role of polymorphonuclear leukocytes (PMNs) has not been adequately defined. We discovered that while B. anthracis 34F2 Sterne endospores germinate poorly within non-activated human PMNs, these phagocytes exhibit rapid microbicidal activity toward the outgrown vegetative bacilli, independent of superoxide and nitric oxide. These findings suggest that a non-free radical pathway kills B. anthracis bacilli. We also find in PMNs an autophagic mechanism of bacterial killing based on the rapid induction of LC-3 conversion, beclin-1 expression, sequestosome 1 (SQSTM1) degradation and inhibition of bactericidal activity by the inhibitor, 3-methyladenine. These findings extend to PMNs an autophagic bactericidal mechanism previously described for other phagocytes. PMID:26424808

  11. Enteric pathogens deploy cell cycle inhibiting factors to block the bactericidal activity of Perforin-2.

    PubMed

    McCormack, Ryan M; Lyapichev, Kirill; Olsson, Melissa L; Podack, Eckhard R; Munson, George P

    2015-09-29

    Perforin-2 (MPEG1) is an effector of the innate immune system that limits the proliferation and spread of medically relevant Gram-negative, -positive, and acid fast bacteria. We show here that a cullin-RING E3 ubiquitin ligase (CRL) complex containing cullin-1 and βTrCP monoubiquitylates Perforin-2 in response to pathogen associated molecular patterns such as LPS. Ubiquitylation triggers a rapid redistribution of Perforin-2 and is essential for its bactericidal activity. Enteric pathogens such as Yersinia pseudotuberculosis and enteropathogenic Escherichia coli disarm host cells by injecting cell cycle inhibiting factors (Cifs) into mammalian cells to deamidate the ubiquitin-like protein NEDD8. Because CRL activity is dependent upon NEDD8, Cif blocks ubiquitin dependent trafficking of Perforin-2 and thus, its bactericidal activity. Collectively, these studies further underscore the biological significance of Perforin-2 and elucidate critical molecular events that culminate in Perforin-2-dependent killing of both intracellular and extracellular, cell-adherent bacteria.

  12. Time-kill determination of the bactericidal activity of telavancin and vancomycin against clinical methicillin-resistant Staphylococcus aureus isolates from cancer patients.

    PubMed

    Rolston, Kenneth Vi; Wang, Weiqun; Nesher, Lior; Smith, Jordan R; Rybak, Michael J; Prince, Randall A

    2017-04-01

    The bactericidal activity of vancomycin and telavancin was compared against 4 clinical methicillin-resistant Staphylococcus aureus isolates recently recovered from cancer patients, using minimum bactericidal concentration (MBC):MIC ratios and time-kill studies. All 4 isolates were susceptible to both agents based on individual MIC values. The 2 methodologies for assessing bactericidal activity produced variable results. Telavancin appeared to have somewhat better bactericidal activity than vancomycin based on narrower MBC:MIC ratios. However, based on the results of the time-kill studies, neither agent demonstrated reliable bactericidal activity (defined as a ≥3 log10 reduction of the starting inoculum at the end of 24hours) against these organisms. These findings might be of some therapeutic importance in certain clinical settings and/or specific patient populations (such as febrile neutropenic patients) in whom potent bactericidal activity is either desired or preferred.

  13. Visible-Light-Induced Bactericidal Activity of Titanium Dioxide Co-doped with Nitrogen and Silver

    PubMed Central

    Wu, Pinggui; Xie, Rongcai; Imlay, Kari; Shang, Jian-Ku

    2011-01-01

    Titanium dioxide nanoparticles co-doped with nitrogen and silver (Ag2O/TiON) were synthesized by the sol-gel process and found to be an effective visible light driven photocatalyst. The catalyst showed strong bactericidal activity against Escherichia coli (E. coli) under visible light irradiation (λ> 400 nm). In x-ray photoelectron spectroscopy and x-ray diffraction characterization of the samples, the as-added Ag species mainly exist as Ag2O. Spin trapping EPR study showed Ag addition greatly enhanced the production of hydroxyl radicals (•OH) under visible light irradiation. The results indicate that the Ag2O species trapped eCB− in the process of Ag2O/TiON photocatalytic reaction, thus inhibiting the recombination of eCB− and hVB+ in agreement with the stronger photocatalytic bactericidal activity of Ag2O/TiON. The killing mechanism of Ag2O/TiON under visible light irradiation is shown to be related to oxidative damages in the forms of cell wall thinning and cell disconfiguration. PMID:20726520

  14. Auranofin exerts broad-spectrum bactericidal activities by targeting thiol-redox homeostasis

    PubMed Central

    Harbut, Michael B.; Vilchèze, Catherine; Luo, Xiaozhou; Hensler, Mary E.; Guo, Hui; Yang, Baiyuan; Chatterjee, Arnab K.; Nizet, Victor; Jacobs, William R.; Schultz, Peter G.; Wang, Feng

    2015-01-01

    Infections caused by antibiotic-resistant bacteria are a rising public health threat and make the identification of new antibiotics a priority. From a cell-based screen for bactericidal compounds against Mycobacterium tuberculosis under nutrient-deprivation conditions we identified auranofin, an orally bioavailable FDA-approved antirheumatic drug, as having potent bactericidal activities against both replicating and nonreplicating M. tuberculosis. We also found that auranofin is active against other Gram-positive bacteria, including Bacillus subtilis and Enterococcus faecalis, and drug-sensitive and drug-resistant strains of Enterococcus faecium and Staphylococcus aureus. Our biochemical studies showed that auranofin inhibits the bacterial thioredoxin reductase, a protein essential in many Gram-positive bacteria for maintaining the thiol-redox balance and protecting against reactive oxidative species. Auranofin decreases the reducing capacity of target bacteria, thereby sensitizing them to oxidative stress. Finally, auranofin was efficacious in a murine model of methicillin-resistant S. aureus infection. These results suggest that the thioredoxin-mediated redox cascade of Gram-positive pathogens is a valid target for the development of antibacterial drugs, and that the existing clinical agent auranofin may be repurposed to aid in the treatment of several important antibiotic-resistant pathogens. PMID:25831516

  15. Comprehensive bactericidal activity of an ethanol-based hand gel in 15 seconds

    PubMed Central

    Kampf, Günter; Hollingsworth, Angela

    2008-01-01

    Background Some studies indicate that the commonly recommended 30 s application time for the post contamination treatment of hands may not be necessary as the same effect may be achieved with some formulations in a shorter application time such as 15 s. Method We evaluated the bactericidal activity of an ethanol-based hand gel (Sterillium® Comfort Gel) within 15 s in a time-kill-test against 11 Gram-positive, 16 Gram-negative bacteria and 11 emerging bacterial pathogens. Each strain was evaluated in quadruplicate. Results The hand gel (85% ethanol, w/w) was found to reduce all 11 Gram-positive and all 16 Gram-negative bacteria by more than 5 log10 steps within 15 s, not only against the ATCC test strains but also against corresponding clinical isolates. In addition, a log10 reduction > 5 was observed against all tested emerging bacterial pathogens. Conclusion The ethanol-based hand gel was found to have a broad spectrum of bactericidal activity in only 15 s which includes the most common species causing nosocomial infections and the relevant emerging pathogens. Future research will hopefully help to find out if a shorter application time for the post contamination treatment of hands provides more benefits or more risks. PMID:18211682

  16. Understanding bactericidal performance on ambient light activated TiO2-InVO4 nanostructured films.

    PubMed

    He, Ziming; Xu, Qingchi; Tan, Timothy Thatt Yang

    2011-12-01

    TiO(2)-InVO(4) nanostructured films were coated onto glass substrates and systematically investigated for their bactericidal activities using Escherichia coli (E. coli) as the model bacterium under ambient light illumination. The uniform TiO(2)-InVO(4) nanostructured films were prepared using titanium isopropoxide (TTIP) as the precursor via a simple sol-gel approach. Polyethylenimine (PEI) was used as a surfactant to ensure uniform dispersion of InVO(4) and a sacrificial pore-inducing agent, generating nanostructured films. Compared to unmodified TiO(2) film, the current TiO(2)-InVO(4) films exhibited enhanced bactericidal activities under ambient light illumination. Bacterial cell "photo-fixation" was demonstrated to be crucial in enhancing the bactericidal activity. A bacterial-nanostructured surface interaction mechanism was proposed for the current ambient-light activated nanostructured film.

  17. Understanding bactericidal performance on ambient light activated TiO2-InVO4 nanostructured films

    NASA Astrophysics Data System (ADS)

    He, Ziming; Xu, Qingchi; Yang Tan, Timothy Thatt

    2011-12-01

    TiO2-InVO4 nanostructured films were coated onto glass substrates and systematically investigated for their bactericidal activities using Escherichia coli (E. coli) as the model bacterium under ambient light illumination. The uniform TiO2-InVO4 nanostructured films were prepared using titanium isopropoxide (TTIP) as the precursor via a simple sol-gel approach. Polyethylenimine (PEI) was used as a surfactant to ensure uniform dispersion of InVO4 and a sacrificial pore-inducing agent, generating nanostructured films. Compared to unmodified TiO2 film, the current TiO2-InVO4 films exhibited enhanced bactericidal activities under ambient light illumination. Bacterial cell ``photo-fixation'' was demonstrated to be crucial in enhancing the bactericidal activity. A bacterial-nanostructured surface interaction mechanism was proposed for the current ambient-light activated nanostructured film.TiO2-InVO4 nanostructured films were coated onto glass substrates and systematically investigated for their bactericidal activities using Escherichia coli (E. coli) as the model bacterium under ambient light illumination. The uniform TiO2-InVO4 nanostructured films were prepared using titanium isopropoxide (TTIP) as the precursor via a simple sol-gel approach. Polyethylenimine (PEI) was used as a surfactant to ensure uniform dispersion of InVO4 and a sacrificial pore-inducing agent, generating nanostructured films. Compared to unmodified TiO2 film, the current TiO2-InVO4 films exhibited enhanced bactericidal activities under ambient light illumination. Bacterial cell ``photo-fixation'' was demonstrated to be crucial in enhancing the bactericidal activity. A bacterial-nanostructured surface interaction mechanism was proposed for the current ambient-light activated nanostructured film. Electronic supplementary information (ESI) available: Photocatalytic activity test procedure and results, AFM images, EDX results, LSCM images, and wettability results. See DOI: 10.1039/c1nr11126d

  18. In vitro bactericidal activity of amoxicillin, gentamicin, rifampicin, ciprofloxacin and trimethoprim-sulfamethoxazole alone or in combination against Listeria monocytogenes.

    PubMed

    Boisivon, A; Guiomar, C; Carbon, C

    1990-03-01

    The in vitro bactericidal activity of amoxicillin, gentamicin, rifampicin, ciprofloxacin and trimethoprim-sulfamethoxazole alone or in combination was determined against seven strains of Listeria monocytogenes by the killing curve method. Amoxicillin plus gentamicin was the most rapidly bactericidal combination, whereas trimethoprim-sulfamethoxazole was less bactericidal at 6 h but as bactericidal at 24 h. The combination of trimethoprim-sulfamethoxazole with either amoxicillin, ciprofloxacin or rifampicin did not result in antagonism, but the combinations were no more active than trimethoprim-sulfamethoxazole alone. The interaction of amoxicillin with rifampin was fairly antagonistic (1 log10 difference). The combination of amoxicillin and ciprofloxacin, although producing antagonism during the first 6 h, was more active at 24 h than amoxicillin alone and prevented the regrowth observed with ciprofloxacin alone. Ciprofloxacin and rifampicin interacted antagonistically during the first 6 h, and the combination was not very bactericidal (3 log10) but prevented the emergence of mutants, as observed with each drug alone, when used at concentrations greater than the MICs for the strain tested. These regimens merit evaluation in in vivo models of Listeria monocytogenes meningitis.

  19. Bactericidal activity of the human skin fatty acid cis-6-hexadecanoic acid on Staphylococcus aureus.

    PubMed

    Cartron, Michaël L; England, Simon R; Chiriac, Alina Iulia; Josten, Michaele; Turner, Robert; Rauter, Yvonne; Hurd, Alexander; Sahl, Hans-Georg; Jones, Simon; Foster, Simon J

    2014-07-01

    Human skin fatty acids are a potent aspect of our innate defenses, giving surface protection against potentially invasive organisms. They provide an important parameter in determining the ecology of the skin microflora, and alterations can lead to increased colonization by pathogens such as Staphylococcus aureus. Harnessing skin fatty acids may also give a new avenue of exploration in the generation of control measures against drug-resistant organisms. Despite their importance, the mechanism(s) whereby skin fatty acids kill bacteria has remained largely elusive. Here, we describe an analysis of the bactericidal effects of the major human skin fatty acid cis-6-hexadecenoic acid (C6H) on the human commensal and pathogen S. aureus. Several C6H concentration-dependent mechanisms were found. At high concentrations, C6H swiftly kills cells associated with a general loss of membrane integrity. However, C6H still kills at lower concentrations, acting through disruption of the proton motive force, an increase in membrane fluidity, and its effects on electron transfer. The design of analogues with altered bactericidal effects has begun to determine the structural constraints on activity and paves the way for the rational design of new antistaphylococcal agents.

  20. Natural Product Anacardic Acid from Cashew Nut Shells Stimulates Neutrophil Extracellular Trap Production and Bactericidal Activity.

    PubMed

    Hollands, Andrew; Corriden, Ross; Gysler, Gabriela; Dahesh, Samira; Olson, Joshua; Raza Ali, Syed; Kunkel, Maya T; Lin, Ann E; Forli, Stefano; Newton, Alexandra C; Kumar, Geetha B; Nair, Bipin G; Perry, J Jefferson P; Nizet, Victor

    2016-07-01

    Emerging antibiotic resistance among pathogenic bacteria is an issue of great clinical importance, and new approaches to therapy are urgently needed. Anacardic acid, the primary active component of cashew nut shell extract, is a natural product used in the treatment of a variety of medical conditions, including infectious abscesses. Here, we investigate the effects of this natural product on the function of human neutrophils. We find that anacardic acid stimulates the production of reactive oxygen species and neutrophil extracellular traps, two mechanisms utilized by neutrophils to kill invading bacteria. Molecular modeling and pharmacological inhibitor studies suggest anacardic acid stimulation of neutrophils occurs in a PI3K-dependent manner through activation of surface-expressed G protein-coupled sphingosine-1-phosphate receptors. Neutrophil extracellular traps produced in response to anacardic acid are bactericidal and complement select direct antimicrobial activities of the compound.

  1. Bactericidal Activity of Rifampin-Amikacin against Mycobacterium ulcerans in Mice

    PubMed Central

    Dega, Herve; Bentoucha, Abdelhalim; Robert, Jerome; Jarlier, Vincent; Grosset, Jacques

    2002-01-01

    To identify the most active curative treatment of Buruli ulcer, two regimens incorporating the use of rifampin (RIF) were compared with the use of RIF alone in a mouse footpad model of Mycobacterium ulcerans infection. Treatments began after footpad swelling from infection and continued for 12 weeks with five doses weekly of one of the following regimens: (i) 10 mg of RIF/kg alone; (ii) 10 mg of RIF/kg and 100 mg of amikacin (AMK)/kg; and (iii) 10 mg of RIF/kg, 100 mg of clarithromycin (CLR)/kg, and 50 mg of sparfloxacin (SPX)/kg. The activity of each regimen was assessed in terms of the reduction of the average lesion index and acid-fast bacillus (AFB) and CFU counts. All three regimens displayed various degrees of bactericidal activity against M. ulcerans. The ranking of bactericidal activity was found to be as follows: RIF-AMK > RIF-CLR-SPX > RIF. RIF-AMK was able to cure M. ulcerans-infected mice and prevent relapse 26 weeks after completion of treatment. To determine the impact of different rhythms of administration of RIF-AMK on the suppression of M.ulcerans growth, mice were given the RIF-AMK combination for 4 weeks but doses were administered either 5 days a week or twice or once weekly. After completion of treatment, the mice were kept under supervision for 30 additional weeks. M. ulcerans was considered to have grown in the footpad if swelling was visually observed and harvests contained more than 5 × 105 AFB per footpad. The proportion of mice in which growth of M. ulcerans occurred, irrespective of drug dosage, was compared with the control mice to determine the proportion of M. ulcerans killed. Each dosage of RIF-AMK was bactericidal for M. ulcerans (P < 0.001), but the effect was significantly stronger in mice treated 5 days per week. The promising results of RIF-AMK treatment in M. ulcerans-infected mice support the clinical trial that is currently in progress under World Health Organization auspices in Ghana. PMID:12234844

  2. New insights into the bactericidal activity of chitosan-Ag bionanocomposite: the role of the electrical conductivity.

    PubMed

    González-Campos, J Betzabé; Mota-Morales, Josué D; Kumar, Siva; Zárate-Triviño, Diana; Hernández-Iturriaga, Montserrat; Prokhorov, Yevgen; Lepe, Milton Vazquez; García-Carvajal, Zaira Y; Sanchez, Isaac C; Luna-Bárcenas, Gabriel

    2013-11-01

    The relationship between electrical conductivity, structure and antibacterial properties of chitosan-silver nanoparticles (CS/AgnP) biocomposites has been analyzed. To test the film's antimicrobial activity, Gram-positive and Gram-negative bacteria were studied. The interactions between silver nanoparticles with chitosan suggest the formation of silver ions which plays a major role in nanocomposite's bactericidal potency. In CS/AgnP biocomposites, the bactericide effectiveness increases by increasing AgnP concentrations up to 3 wt%, which is close to the electrical percolation threshold of ca. 3 wt%. As the AgnP concentration increases above this threshold, the bactericidal potency is greatly diminished. The elucidated correlation between electrical conductivity and antibacterial activity could be useful in the design of other nanocomposites that involve polymeric-based matrices.

  3. Bactericidal efficacy of electrochemically activated solutions and of commercially available hypochlorite.

    PubMed

    Helme, A J; Ismail, M N; Scarano, F J; Yang, C L

    2010-01-01

    Electrochemical activation (ECA) has been developed as a quick and efficient method of hypochlorite production, and many claim increased efficacy when compared to conventional disinfectant solutions. Numerous potential applications, including hospital disinfection, waste-water treatment, routine drinking water disinfection and biological decontamination have been suggested. In this study, three solutions were produced by electrochemical activation of 0.5% NaCl and compared to commercially available NaOCl. The NaOCl concentration and pH of each solution was measured, and the minimum bactericidal concentration of each was determined using seven common microbial pathogens. All solutions were effective, the most significant of which was the ECA anolyte solution. This is notable due to its neutral pH and antimicrobial efficacy that is four times that of commercially available NaOCl. This process may lead to production of a highly effective yet non-caustic disinfectant that would have countless scientific, medical, military and public health applications.

  4. [Comparative study of 2 methods to determine the in vivo bactericidal activity of antiseptics].

    PubMed

    Chantefort, A; Mahwachi, M; Druilles, J; Cassanas, G; Jourdan, R

    1990-05-01

    In France in 1990, there is no standardized method to study the bactericidal activity in vivo of antiseptics. A comparative study of the Williamson-Kligmann techniques (on the epidermis of the forearm) and of the bag of Gaschen (on the hands) has been carried out by using 11 products and 10 volunteers for each of them. On the forearm, the rates of reduction of the number of bacterias numbered in decimal logarithms are significantly much higher to those measured on the hand. After having stated the advantages and drawbacks of each of these two techniques, an account fort the differences in the activity that have been observed is suggested. None of these two techniques is universal and one or the other has to be used according to the therapeutic prescription (antisepsy of the normal skin or of the hands) of the patent medicine.

  5. Pharmacokinetics and serum bactericidal activities of quinolones in combination with clindamycin, metronidazole, and ornidazole.

    PubMed Central

    Boeckh, M; Lode, H; Deppermann, K M; Grineisen, S; Shokry, F; Held, R; Wernicke, K; Koeppe, P; Wagner, J; Krasemann, C

    1990-01-01

    To enhance the antimicrobial spectrum of the quinolones against anaerobic organisms and gram-positive bacteria, we investigated in two studies the parenteral combinations of ciprofloxacin (200 mg) and ofloxacin (200 mg) with metronidazole (500 mg) or clindamycin (600 mg) and the oral combinations of enoxacin (400 mg) and fleroxacin (400 mg) with metronidazole (400 mg), clindamycin (300 mg), or ornidazole (500 mg) (only with fleroxacin). The pharmacokinetics and serum bactericidal activities (SBAs) against 5 aerobic and 2 anaerobic species (total, 58 strains) were determined in two groups of 10 healthy volunteers by using a randomized crossover study design. The additions of metronidazole, clindamycin, and ornidazole did not affect the pharmacokinetics of the quinolones. The combination of clindamycin with ciprofloxacin, ofloxacin, and, to a lesser extent, fleroxacin resulted in an increase of the SBA against gram-positive strains (mean peak titers): Staphylococcus aureus, ciprofloxacin alone, 1:5.5; ciprofloxacin-clindamycin, 1:19.9; ofloxacin alone, 1:3.6; ofloxacin-clindamycin, 1:17.5; fleroxacin alone, 1:4.3; fleroxacin-clindamycin, 1:8.1; Streptococcus pneumoniae (fleroxacin and enoxacin were not tested), ciprofloxacin alone, 1:2.0; ciprofloxacin-clindamycin, 1:53; ofloxacin alone, 1:2.6; and ofloxacin-clindamycin, 1:49.2. The high SBA of quinolones against gram-negative bacteria was not affected by the combinations; however, relatively low activities against Pseudomonas aeruginosa were detected. In general, against anaerobic bacteria, low bactericidal activities were determined in both studies (mean peak titers ranged from 1:2.1 to 1:3.1; mean trough titers range from 1:2.0 to 1:2.9). In clinical settings with severe mixed infections, a parenteral therapy consisting of modern quinolones together with clindamycin or imidazole derivatives seems to be active and offers no obvious interactions. PMID:2088195

  6. Low molecular weight chitosan--preparation with the aid of pepsin, characterization, and its bactericidal activity.

    PubMed

    Kumar, B Acharya Vishu; Varadaraj, Mandyam C; Tharanathan, Rudrapatnam N

    2007-02-01

    Pepsin (EC 3.4.4.1) from porcine stomach mucosa caused depolymerization of a chitosan sample (a copolymer of glucosamine and N-acetylglucosamine linked by beta-1-4-glycosidic bonds). N-terminal sequence and zymogram analyses confirmed dual (proteolytic and chitosanolytic) activities of pepsin. Optimum depolymerization occurred at pH 5.0 and 45 degrees C with an activity of 4.98 U. Low molecular weight chitosan (LMWC), the major depolymerization product, was obtained in a yield of 75-82%, the degree of polymerization of which depended on reaction time. The LMWC showed a nearly 10-14-fold decrease in the molecular mass as compared to native chitosan, which was also confirmed by GPC and HPLC analyses. IR and 13C NMR spectra indicated a decrease in the degree of acetylation (DA, approximately 13.4-18.8%) as compared to native chitosan (approximately 25.7%), which was in accordance with the CD analysis. Native chitosan had a crystallinity index (CrI) of approximately 70%, whereas there was a decrease in the CrI of LMWC (approximately 61%). The latter showed a better bactericidal activity toward both Bacillus cereus and Escherichia coli, which was more toward the former. The bactericidal activity was essentially due to the lytic and not static effect of LMWC, as evidenced by the pore formation on the bacterial cell surface when observed under SEM. This study suggests the possible use of pepsin in place of chitosanase, which is expensive and unavailable in bulk quantities for the production of LMWC of desired molecular mass that has diversified applications in various fields.

  7. The effect of an NADH oxidase inhibitor (hydrocortisone) on polymorphonuclear leukocyte bactericidal activity

    PubMed Central

    Mandell, Gerald L.; Rubin, Walter; Hook, Edward W.

    1970-01-01

    Polymorphonuclear neutrophils (PMN) from patients with chronic granulomatous disease of childhood have impaired bactericidal activity and are deficient in diphosphopyridine nucleotide, reduced form of, (NADH) oxidase. Since hydrocortisone had been shown to inhibit NADH oxidation, experiments were undertaken to determine the effect of hydrocortisone on several parameters of human PMN function. The phagocytic and bactericidal capacity of PMN with or without hydrocortisone (2.1 mM) was determined by quantitation of cell-free, cell-associated, and total bacteria. Phagocytosis of Staphylococcus aureus and several gram-negative rods was unimpaired by the presence of hydrocortisone in the media. In contrast, killing of bacteria was markedly impaired by hydrocortisone. After 30 min of incubation, there were 20-400 times as many bacteria surviving in hydrocortisone-treated PMN as in simultaneously run controls without hydrocortisone. The defect of intracellular killing noted in the presence of hydrocortisone was not related to impaired degranulation. Quantitative kinetic studies of degranulation revealed no difference in the release of granule associated acid phosphatase in hydrocortisone-treated and control PMN after phagocytosis. Electron microscopy of PMN also indicated that the presence of hydrocortisone had no effect on the extent of degranulation after phagocytosis. These observations were confirmed by studies using histochemical techniques to detect lysosomal enzymes. After phagocytosis, hydrocortisone-treated PMN demonstrated less NADH oxidase activity, oxygen consumption, and hydrogen peroxide production than postphagocytic control PMN. In addition, Nitro blue tetrazolium dye reduction was diminished in hydrocortisone-treated PMN. Thus, impairment of NADH oxidase activity in normal human PMN by hydrocortisone results in reduced intracellular killing of bacteria, diminished postphagocytic oxygen consumption, decreased ability to reduce Nitro blue tetrazolium, and

  8. Lipopolysaccharide induction of autophagy is associated with enhanced bactericidal activity in Dictyostelium discoideum

    PubMed Central

    Pflaum, Katherine; Gerdes, Kimberly; Yovo, Kossi; Callahan, Jennifer; Snyder, Michelle L.D.

    2012-01-01

    Innate immune cells respond to microbial invaders using pattern recognition receptors that detect conserved microbial patterns. Among the cellular processes stimulated downstream of pattern recognition machinery is the initiation of autophagy, which plays protective roles against intracellular microbes. We have shown recently that Dictyostelium discoideum, which takes up bacteria for nutritive purposes, may employ pattern recognition machinery to respond to bacterial prey, as D. discoideum cells upregulate bactericidal activity upon stimulation by lipopolysaccharide (LPS). Here we extend these findings, showing that LPS treatment leads to induction of autophagosomal maturation in cells responding to the bacteria Staphylococcus aureus. Cells treated with the autophagy-inducing drug rapamycin clear internalized bacteria at an accelerated rate, while LPS-enhanced clearance of bacteria is reduced in cells deficient for the autophagy-related genes atg1 and atg9. These findings link microbial pattern recognition with autophagy in the social amoeba D. discoideum. PMID:22575510

  9. Coleus aromaticus leaf extract mediated synthesis of silver nanoparticles and its bactericidal activity

    NASA Astrophysics Data System (ADS)

    Vanaja, Mahendran; Annadurai, Gurusamy

    2013-06-01

    The utilization of various plant resources for the biosynthesis of metallic nanoparticles is called green nanotechnology, and it does not utilize any harmful chemical protocols. The present study reports the plant-mediated synthesis of silver nanoparticles using the plant leaf extract of Coleus aromaticus, which acts as a reducing and capping agent. The silver nanoparticles were characterized by ultraviolet visible spectroscopy, X-ray diffraction, scanning electron microscopy, energy-dispersive X-ray spectroscopy, Fourier transform infrared spectroscopy, and the size of the silver nanoparticles is 44 nm. The bactericidal activity of the silver nanoparticles was carried out by disc diffusion method that showed high toxicity against Bacillus subtilis and Klebsiella planticola. Biosynthesis of silver nanoparticles by using plant resources is an eco-friendly, reliable process and suitable for large-scale production. Moreover, it is easy to handle and a rapid process when compared to chemical, physical, and microbe-mediated synthesis process.

  10. Serum and blister fluid pharmacokinetics and bactericidal activities of ampicillin-sulbactam, cefotetan, cefoxitin, ceftizoxime, and ticarcillin-clavulanate.

    PubMed

    Jaresko, G S; Barriere, S L; Johnson, B L

    1992-10-01

    Ampicillin-sulbactam, ticarcillin-clavulanate, cefoxitin, cefotetan, and ceftizoxime are promoted for the treatment of mixed aerobic-anaerobic bacterial infections. Their activities have been compared in vitro but not in vivo. In order to assess the in vivo activities of these agents in serum and interstitial fluid, we administered single, intravenous doses of these antimicrobial agents to healthy subjects. Concentrations of the antimicrobial agents in serum and suction-induced blister fluid and bactericidal activity were measured by high-pressure liquid chromatography and the standard methodology of the National Committee for Clinical Laboratory Standards, respectively. The organisms used for bactericidal activity tests were one isolate each of Staphylococcus aureus, Klebsiella pneumoniae, and Bacteroides fragilis. Pharmacokinetic parameters in serum and blister fluid were similar to those derived in other investigations. Of note were the high and prolonged concentrations of ticarcillin and cefotetan in blister fluid, despite high-level serum protein binding. The bactericidal activities in serum and blister fluid reflected the relative in vitro activities and kinetic dispositions of the various antimicrobial agents except for the bactericidal activity of cefotetan, which was substantially lower in blister fluid than serum, despite a blister fluid:serum area under the concentration-time curve ratio of 1.5. Similarly, the activity of ticarcillin-clavulanate in blister fluid was also substantially less than would have been predicted by the blister fluid:serum ratio of the area under the concentration-time curve of 1.1, possibly because of the low concentrations of clavulanate in blister fluid. The rankings of the in vivo bactericidal activities of the five drugs were as follows: for S. aureus, ampicillin-sulbactam > ticarcillin-clavulanate > ceftizoxime > cefoxitin > cefotetan; for K. pneumoniae, ceftizoxime > cefotetan > ampicillin-sulbactam = ticarcillin

  11. Effects of recombinant bactericidal/permeability-increasing protein (rBPI23) on neutrophil activity in burned rats.

    PubMed

    Hansbrough, J; Tenenhaus, M; Wikstrom, T; Braide, M; Rennekampff, O H; Kiessig, V; Bjursten, L M

    1996-06-01

    Bactericidal/permeability-increasing protein (BPI) is a neutrophil granule protein with potent bactericidal and lipopolysaccharide (LPS)-neutralizing activities. The purpose of this study was to determine if a human recombinant BPI product, rBPI23, would influence neutrophil (PMN) sequestration into various tissues in a rat burn injury model. Leukosequestration may produce local tissue injury from proteases and high-energy oxygen species released from PMNs. Rats received tracheostomy and venous cannulation, then received 17 to 20% total body surface area full-thickness contact burns and resuscitation with 20 ml, of intraperitoneal saline. Ten mg/kg body weight rBPI23 in saline was given by intravenous injection immediately after burn injury, followed by intravenous doses of 2 mg/kg at 2 and 4 hours. Control animals received intravenous saline only. PMN retention in lung, liver, spleen, gut, skin, muscle, kidney, and brain tissues was determined by removing (before burn injury) and differentially radiolabeling PMNs (111In) and erythrocytes (51Cr), reinfusing cells 4.5 hours after burn injury, and measuring tissue radioactivity 30 minutes later. Edema was estimated by measuring extravasated 125I-labeled albumin in the various tissues, 30 minutes after injection. Peripheral blood PMNS were analyzed for intracellular H2O2 content by flow cytometry using a fluorescent dye that reacts with H2O2. Radioisotope studies demonstrated significant (p < 0.05) leukosequestration into lung, liver, gut, kidney, and skin tissues at 5 hours after burn injury. Tissue edema, manifested by radiolabeled albumin retention, was not observed in any tissues. Postburn PMN deposition in lungs and skin was decreased (p < 0.05) by the immediate administration of rBPI23 after burn injury. Flow cytometry showed increased intracellular H2O2 content in peripheral blood PMNs 5 hours after burn injury (p < 0.05), which was unaffected by administration of rBPI23. Since sequestration of metabolically

  12. Determination of optimal dosage regimen for amikacin in healthy volunteers by study of pharmacokinetics and bactericidal activity.

    PubMed Central

    Garraffo, R; Drugeon, H B; Dellamonica, P; Bernard, E; Lapalus, P

    1990-01-01

    The pharmacokinetics and serum killing curves of amikacin, which was administered by a 30-minute intravenous infusion of single doses of 7.5 mg/kg and then 15 mg/kg, were investigated in six healthy volunteers who received the two doses in a crossover study with a washout period of 20 days. The serum killing curves were determined for four bacterial species: Escherichia coli, Serratia marcescens, Enterobacter cloacae, and Pseudomonas aeruginosa. All strains were serum resistant, and the bactericidal activity was analyzed by separating the early phase (first 5 h) and the late phase (24 h) of the killing curve. For the early phase, the bactericidal activity was evaluated by correlating an index of surviving bacteria with amikacin concentrations. This methodology allowed determination of two parameters: the maximal effective concentration and the lowest effective concentration. For the late phase, the threshold values separating bacteriostatic and bactericidal activities were lower than 10 mg/liter for each strain. The concentration dependence of amikacin bactericidal activity was confirmed for Escherichia coli and Enterobacter cloacae and, to a lesser extent, for Serratia marcescens and Pseudomonas aeruginosa. Correlation of these data with amikacin pharmacokinetic data in volunteers indicated that a daily dose of 15 mg/kg may be effective in the treatment of Escherichia coli and Enterobacter cloacae infections. For Pseudomonas aeruginosa and Serratia marcescens, the partially time-dependent activity probably necessitates two daily administrations and combination with another antibiotic. PMID:2111658

  13. The Effect of Long-Term Storage on the Physiochemical and Bactericidal Properties of Electrochemically Activated Solutions

    PubMed Central

    Robinson, Gareth; Thorn, Robin; Reynolds, Darren

    2013-01-01

    Electrochemically activated solutions (ECAS) are generated by electrolysis of NaCl solutions, and demonstrate broad spectrum antimicrobial activity and high environmental compatibility. The biocidal efficacy of ECAS at the point of production is widely reported in the literature, as are its credentials as a “green biocide.” Acidic ECAS are considered most effective as biocides at the point of production and ill suited for extended storage. Acidic ECAS samples were stored at 4 °C and 20 °C in glass and polystyrene containers for 398 days, and tested for free chlorine, pH, ORP and bactericidal activity throughout. ORP and free chlorine (mg/L) in stored ECAS declined over time, declining at the fastest rate when stored at 20 °C in polystyrene and at the slowest rate when stored at 4 °C in glass. Bactericidal efficacy was also affected by storage and ECAS failed to produce a 5 log10 reduction on five occasions when stored at 20 °C. pH remained stable throughout the storage period. This study represents the longest storage evaluation of the physiochemical parameters and bactericidal efficacy of acidic ECAS within the published literature and reveals that acidic ECAS retain useful bactericidal activity for in excess of 12 months, widening potential applications. PMID:23263673

  14. Bactericidal activity of copper-deposited TiO2 thin film under weak UV light illumination.

    PubMed

    Sunada, Kayano; Watanabe, Toshiya; Hashimoto, Kazuhito

    2003-10-15

    The bactericidal activity of copper-deposited titanium dioxide thin film (Cu/TiO2) was investigated under very weak ultraviolet (UV) light illumination. To elucidate the roles of the film photocatalyst and the deposited copper in the bactericidal activity, cells from a copper-resistant Escherichia coli (E. coli) strain were utilized. A decrease in survival rate was not observed with the copper-resistant cells under dark conditions, but when illuminated with a very weak UV intensity of 1 microW/cm2, the survival rate decreased, suggesting photocatalytic bactericidal activity. The decay curve of survival on the Cu/TiO2 film under very weak UV light illumination consisted of two steps, similar to the survival change of normal E. coli on TiO2 films under rather strong UV illumination. The first step is due to the partial decomposition of the outer membrane in the cell envelope by a photocatalytic process, followed by permeation of the copper ions into the cytoplasmic membrane. The second step is due to a disorder of the cytoplasmic membrane caused by the copper ions, which results in a loss of the cell's integrity. These processes explain why the Cu/TiO2 film system shows an effective bactericidal activity even under very weak UV light illumination.

  15. Triggering through NOD-2 Differentiates Bone Marrow Precursors to Dendritic Cells with Potent Bactericidal activity

    PubMed Central

    Khan, Nargis; Aqdas, Mohammad; Vidyarthi, Aurobind; Negi, Shikha; Pahari, Susanta; Agnihotri, Tapan; Agrewala, Javed N.

    2016-01-01

    Dendritic cells (DCs) play a crucial role in bridging innate and adaptive immunity by activating naïve T cells. The role of pattern recognition receptors like Toll-Like Receptors and Nod-Like Receptors expressed on DCs is well-defined in the recognition of the pathogens. However, nothing is precisely studied regarding the impact of NOD-2 signaling during the differentiation of DCs. Consequently, we explored the role of NOD-2 signaling in the differentiation of DCs and therefore their capability to activate innate and adaptive immunity. Intriguingly, we observed that NOD-2 stimulated DCs (nDCs) acquired highly activated and matured phenotype and exhibited substantially greater bactericidal activity by robust production of nitric oxide. The mechanism involved in improving the functionality of nDCs was dependent on IFN-αβ signaling, leading to the activation of STAT pathways. Furthermore, we also observed that STAT-1 and STAT-4 dependent maturation and activation of DCs was under the feedback mechanism of SOCS-1 and SOCS-3 proteins. nDCs acquired enhanced potential to activate chiefly Th1 and Th17 immunity. Taken together, these results suggest that nDCs can be exploited as an immunotherapeutic agent in bolstering host immunity and imparting protection against the pathogens. PMID:27265209

  16. Anti-listerial Bactericidal Activity of Lactobacillus plantarum DM5 Isolated from Fermented Beverage Marcha.

    PubMed

    Das, Deeplina; Goyal, Arun

    2013-09-01

    The strain Lactobacillus plantarum DM5 was isolated from fermented beverage Marcha of Sikkim and explored for its antagonistic activity against food-borne pathogens. The cell-free supernatant of L. plantarum DM5 showed antibacterial activity of 6,400 AU/mL in MRS medium (pH 6.0) against the indicator strain Staphylococcus aureus. MRS medium supplemented with 15 g/L of maltose at 37 °C under static condition yielded highest antimicrobial activity (6,400 AU/mL) with 3 % increase in specific activity when compared to 20 g/L glucose. The antimicrobial compound was heat stable (60 min at 100 °C) and was active over a wide pH range. It showed bactericidal effect on S. aureus and Listeria monocytogenes by causing 96 and 98 % of cell lysis, respectively. The cell morphology of the treated S. aureus and L. monocytogenes was completely deformed as revealed by scanning electron microscopy, suggesting the high potential of L. plantarum DM5 as natural preservatives in food industry. The antimicrobial compound was purified by 80 % ammonium sulphate precipitation and showed antimicrobial activity of 12,800 AU/mL with 19-fold purification and a molecular mass of 15.2 kDa, indicating the proteinaceous nature of the compound.

  17. Shape-dependent bactericidal activity of copper oxide nanoparticle mediated by DNA and membrane damage

    SciTech Connect

    Laha, Dipranjan; Pramanik, Arindam; Laskar, Aparna; Jana, Madhurya; Pramanik, Panchanan; Karmakar, Parimal

    2014-11-15

    Highlights: • Spherical and sheet shaped copper oxide nanoparticles were synthesized. • Physical characterizations of these nanoparticles were done by TEM, DLS, XRD, FTIR. • They showed shape dependent antibacterial activity on different bacterial strain. • They induced both membrane damage and ROS mediated DNA damage in bacteria. - Abstract: In this work, we synthesized spherical and sheet shaped copper oxide nanoparticles and their physical characterizations were done by the X-ray diffraction, fourier transform infrared spectroscopy, transmission electron microscopy and dynamic light scattering. The antibacterial activity of these nanoparticles was determined on both gram positive and gram negative bacterial. Spherical shaped copper oxide nanoparticles showed more antibacterial property on gram positive bacteria where as sheet shaped copper oxide nanoparticles are more active on gram negative bacteria. We also demonstrated that copper oxide nanoparticles produced reactive oxygen species in both gram negative and gram positive bacteria. Furthermore, they induced membrane damage as determined by atomic force microscopy and scanning electron microscopy. Thus production of and membrane damage are major mechanisms of the bactericidal activity of these copper oxide nanoparticles. Finally it was concluded that antibacterial activity of nanoparticles depend on physicochemical properties of copper oxide nanoparticles and bacterial strain.

  18. Biofilm-forming activity of bacteria isolated from toilet bowl biofilms and the bactericidal activity of disinfectants against the isolates.

    PubMed

    Mori, Miho; Gomi, Mitsuhiro; Matsumune, Norihiko; Niizeki, Kazuma; Sakagami, Yoshikazu

    2013-01-01

    To evaluate the sanitary conditions of toilets, the bacterial counts of the toilet bowl biofilms in 5 Kansai area and 11 Kansai and Kanto area homes in Japan were measured in winter and summer seasons, respectively. Isolates (128 strains) were identified by analyzing 16S ribosomal RNA sequences. The number of colonies and bacterial species from biofilms sampled in winter tended to be higher and lower, respectively, than those in summer. Moreover, the composition of bacterial communities in summer and winter samples differed considerably. In summer samples, biofilms in Kansai and Kanto areas were dominated by Blastomonas sp. and Mycobacterium sp., respectively. Methylobacterium sp. was detected in all toilet bowl biofilms except for one sample. Methylobacterium sp. constituted the major presence in biofilms along with Brevundimonas sp., Sphingomonas sp., and/or Pseudomonas sp. The composition ratio of the sum of their genera was 88.0 from 42.9% of the total bacterial flora. The biofilm formation abilities of 128 isolates were investigated, and results suggested that Methylobacterium sp. and Sphingomonas sp. were involved in biofilm formation in toilet bowls. The biofilm formation of a mixed bacteria system that included bacteria with the highest biofilm-forming ability in a winter sample was greater than mixture without such bacteria. This result suggests that isolates possessing a high biofilm-forming activity are involved in the biofilm formation in the actual toilet bowl. A bactericidal test against 25 strains indicated that the bactericidal activities of didecyldimethylammonium chloride (DDAC) tended to be higher than those of polyhexamethylene biguanide (PHMB) and N-benzyl-N,N-dimethyldodecylammonium chloride (ADBAC). In particular, DDAC showed high bactericidal activity against approximately 90% of tested strains under the 5 h treatment.

  19. Design, synthesis and structure-bactericidal activity relationships of novel 9-oxime ketolides and reductive epimers of acylides.

    PubMed

    Tian, Jing-Chao; Han, Xu; Lv, Wei; Li, Ya-Xin; Wang, Hui; Fan, Bing-Zhi; Cushman, Mark; Liang, Jian-Hua

    2017-04-01

    Erythromycin was long viewed as a bacteriostatic agent. The erythromycin derivatives, 9-oxime ketolides have a species-specific bactericidal profile. Among them, the 3'-allyl version of the 9-oxime ketolide 1 (Ar=3-quinolyl; 17a) is bactericidal against Streptococcus pneumoniae and Streptococcus pyogenes. In contrast, the 2-fluoro analogs of 1, 13a (Ar=6-quinolyl), 13b (Ar=3-quinolyl) and 24a (Ar=4-isoquinolyl), show bactericidal activities against S. pneumoniae, Staphylococcus aureus and Moraxella catarrhalis, while the 2-fluoro analogs 13c (Ar=3-aminopyridyl) and 24b (Ar=3-carbamoylpyridyl) are only bactericidal against S. pneumoniae and Haemophilus influenzae. Reduction of the ketolides led to novel epiacylides, the 3-O-epimers of the acylides. Alteration of linker length (30b vs. 30a), 2-fluorination (33 vs. 30a) and incorporation of additional spacers at the 9-oxime or 6-OH (35, 40 vs. 30a) did not restore the epiacylides back to be as active as the acylide 31. Molecular docking suggested that epimerization at the 3-position reshapes the orientation of the 3-O-sidechain and leads to considerably weaker binding with bacterial ribosomes.

  20. Bactericidal Activity Does Not Predict Sterilizing Activity: The Case of Rifapentine in the Murine Model of Mycobacterium ulcerans Disease

    PubMed Central

    Almeida, Deepak V.; Converse, Paul J.; Li, Si-Yang; Tyagi, Sandeep; Nuermberger, Eric L.; Grosset, Jacques H.

    2013-01-01

    Background Since 2004, treatment of Mycobacterium ulcerans disease, or Buruli ulcer, has shifted from surgery to daily treatment with streptomycin (STR) + rifampin (RIF) for 8 weeks. For shortening treatment duration, we tested the potential of daily rifapentine (RPT), a long-acting rifamycin derivative, as a substitute for RIF. Methodology/Principal Findings BALB/c mice were infected with M. ulcerans in the right hind footpad and treated either daily (7/7) with STR+RIF or five days/week (5/7) with STR+RIF or STR+RPT for 4 weeks, beginning 28 days after infection when CFU counts were 4.88±0.51. The relative efficacy of the drug treatments was compared by footpad CFU counts during treatment and median time to footpad swelling after treatment cessation as measure of sterilizing activity. All drug treatments were bactericidal. After 1 week of treatment, the decline in CFU counts was significantly greater in treated mice but not different between the three treated groups. After 2 weeks of treatment, the decline in CFU was greater in mice treated with STR+RPT 5/7 than in mice treated with STR+RIF 7/7 and STR+RIF 5/7. After 3 and 4 weeks of treatment, CFU counts were nil in mice treated with STR+RPT and reduced by more than 3 and 4 logs in mice treated with STR+RIF 5/7 and STR+RIF 7/7, respectively. In sharp contrast to the bactericidal activity, the sterilizing activity was not different between all drug regimens although it was in proportion to the treatment duration. Conclusions/Significance The better bactericidal activity of daily STR+RIF and especially of STR+RPT did not translate into better prevention of relapse, possibly because relapse-freecure after treatment of Buruli ulcer is more related to the reversal of mycolactone-induced local immunodeficiency by drug treatment rather than to the bactericidal potency of drugs. PMID:23469308

  1. Expression, secretion and bactericidal activity of type VI secretion system in Vibrio anguillarum.

    PubMed

    Tang, Lei; Yue, Shu; Li, Gui-Yang; Li, Jie; Wang, Xiao-Ran; Li, Shu-Fang; Mo, Zhao-Lan

    2016-10-01

    The type VI secretion system (T6SS) was recently shown to modulate quorum sensing and the stress response in Vibrio anguillarum serotype O1 strain NB10. It is not known whether there is a functionally active T6SS in other serotypes of V. anguillarum. Here, homologues to T6SS cluster VtsEFGH and hemolysin-coregulated protein (Hcp)-encoding genes were found to be prevalent and conserved in clinical isolates of V. anguillarum from fish, including four O1 and five non-O1 serotype strains. Unexpectedly, only the non-O1 serotype strains expressed VtsEFGH and Hcp under laboratory and marine-like conditions, in contrast to the serotype O1 strains. This suggested that the V. anguillarum non-O1 serotype strains tested have constitutive expression of T6SS. Examination of a representative non-O1 strain, MHK3, showed that Hcp production was growth phase dependent and that maximum Hcp production was observed in the exponential growth phase. Moreover, Hcp production by MHK3 was most active under warm marine-like conditions. Further examination revealed a correlation of the constitutive expression of T6SS with bactericidal activity against Escherichia coli and Edwardsiella tarda. The work presented here suggests that the constitutive expression of T6SS provides V. anguillarum with advantage in microbial competition in marine environments.

  2. Detection and characterisation of Complement protein activity in bovine milk by bactericidal sequestration assay.

    PubMed

    Maye, Susan; Stanton, Catherine; Fitzgerald, Gerald F; Kelly, Philip M

    2015-08-01

    While the Complement protein system in human milk is well characterised, there is little information on its presence and activity in bovine milk. Complement forms part of the innate immune system, hence the importance of its contribution during milk ingestion to the overall defences of the neonate. A bactericidal sequestration assay, featuring a Complement sensitive strain, Escherichia coli 0111, originally used to characterise Complement activity in human milk was successfully applied to freshly drawn bovine milk samples, thus, providing an opportunity to compare Complement activities in both human and bovine milks. Although not identical in response, the levels of Complement activity in bovine milk were found to be closely comparable with that of human milk. Differential counts of Esch. coli 0111 after 2 h incubation were 6.20 and 6.06 log CFU/ml, for raw bovine and human milks, respectively - the lower value representing a stronger Complement response. Exposing bovine milk to a range of thermal treatments e.g. 42, 45, 65, 72, 85 or 95 °C for 10 min, progressively inhibited Complement activity by increasing temperature, thus confirming the heat labile nature of this immune protein system. Low level Complement activity was found, however, in 65 and 72 °C heat treated samples and in retailed pasteurised milk which highlights the outer limit to which high temperature, short time (HTST) industrial thermal processes should be applied if retention of activity is a priority. Concentration of Complement in the fat phase was evident following cream separation, and this was also reflected in the further loss of activity recorded in low fat variants of retailed pasteurised milk. Laboratory-based churning of the cream during simulated buttermaking generated an aqueous (buttermilk) phase with higher levels of Complement activity than the fat phase, thus pointing to a likely association with the milk fat globule membrane (MFGM) layer.

  3. Antibiotic Bactericidal Activity Is Countered by Maintaining pH Homeostasis in Mycobacterium smegmatis

    PubMed Central

    Bartek, I. L.; Reichlen, M. J.; Honaker, R. W.; Leistikow, R. L.; Clambey, E. T.; Scobey, M. S.; Hinds, A. B.; Born, S. E.; Covey, C. R.; Schurr, M. J.; Lenaerts, A. J.

    2016-01-01

    ABSTRACT Antibiotics target specific biosynthetic processes essential for bacterial growth. It is intriguing that several commonalities connect the bactericidal activity of seemingly disparate antibiotics, such as the numerous conditions that confer broad-spectrum antibiotic tolerance. Whether antibiotics kill in a manner unique to their specific targets or by a universal mechanism is a critical and contested subject. Herein, we demonstrate that the bactericidal activity of diverse antibiotics against Mycobacterium smegmatis and four evolutionarily divergent bacterial pathogens was blocked by conditions that worked to maintain intracellular pH homeostasis. Single-cell pH analysis demonstrated that antibiotics increased the cytosolic pH of M. smegmatis, while conditions that promoted proton entry into the cytosol prevented intracellular alkalization and antibiotic killing. These findings led to a hypothesis that posits antibiotic lethality occurs when antibiotics obstruct ATP-consuming biosynthetic processes while metabolically driven proton efflux is sustained despite the loss of proton influx via ATP synthase. Consequently, without a concomitant reduction in respiratory proton efflux, cell death occurs due to intracellular alkalization. Our findings indicate the effects of antibiotics on pH homeostasis should be considered a potential mechanism contributing to antibiotic lethality. IMPORTANCE Since the discovery of antibiotics, mortality due to bacterial infection has decreased dramatically. However, infections from difficult to treat bacteria such as Mycobacterium tuberculosis and multidrug-resistant pathogens have been on the rise. An understanding of the cascade of events that leads to cell death downstream of specific drug-target interactions is not well understood. We have discovered that killing by several classes of antibiotics was stopped by maintaining pH balance within the bacterial cell, consistent with a shared mechanism of antibiotic killing. Our

  4. NF-κB activation is critical for bacterial lipoprotein tolerance-enhanced bactericidal activity in macrophages during microbial infection

    PubMed Central

    Liu, Jinghua; Xiang, Jing; Li, Xue; Blankson, Siobhan; Zhao, Shuqi; Cai, Junwei; Jiang, Yong; Redmond, H. Paul; Wang, Jiang Huai

    2017-01-01

    Tolerance to bacterial components represents an essential regulatory mechanism during bacterial infection. Bacterial lipoprotein (BLP)-induced tolerance confers protection against microbial sepsis by attenuating inflammatory responses and augmenting antimicrobial activity in innate phagocytes. It has been well-documented that BLP tolerance-attenuated proinflammatory cytokine production is associated with suppressed TLR2 signalling pathway; however, the underlying mechanism(s) involved in BLP tolerance-enhanced antimicrobial activity is unclear. Here we report that BLP-tolerised macrophages exhibited accelerated phagosome maturation and enhanced bactericidal activity upon bacterial infection, with upregulated expression of membrane-trafficking regulators and lysosomal enzymes. Notably, bacterial challenge resulted in a strong activation of NF-κB pathway in BLP-tolerised macrophages. Importantly, activation of NF-κB pathway is critical for BLP tolerance-enhanced antimicrobial activity, as deactivation of NF-κB in BLP-tolerised macrophages impaired phagosome maturation and intracellular killing of the ingested bacteria. Finally, activation of NF-κB pathway in BLP-tolerised macrophages was dependent on NOD1 and NOD2 signalling, as knocking-down NOD1 and NOD2 substantially inhibited bacteria-induced activation of NF-κB and overexpression of Rab10 and Acp5, two membrane-trafficking regulators and lysosomal enzymes contributed to BLP tolerance-enhanced bactericidal activity. These results indicate that activation of NF-κB pathway is essential for BLP tolerance-augmented antimicrobial activity in innate phagocytes and depends primarily on both NOD1 and NOD2. PMID:28079153

  5. Biofunctionalization of microgroove titanium surfaces with an antimicrobial peptide to enhance their bactericidal activity and cytocompatibility.

    PubMed

    Zhou, Lin; Lai, Yingzhen; Huang, Wenxiu; Huang, Sijia; Xu, Zhiqiang; Chen, Jiang; Wu, Dong

    2015-04-01

    A firm peri-implant soft tissue seal is important for the long-term survival of dental implants, which demands the properties of antibacterial and cytocompatibility of the implant surfaces. In this study, GL13K, a cationic antimicrobial peptide, was immobilized onto microgroove surfaces which were 60 μm in width and 10 μm in depth, and the modified surfaces improved both the properties of antibacterial and cytocompatibility. The method of silanization was used to immobilize the antimicrobial peptide GL13K, which was confirmed by X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), atomic force microscopy (AFM), water contact angle measurement. Then the mechanical stability of the coatings was confirmed by ultrasonication. In vitro antibacterial tests confirmed bactericidal activity against Porphyromonas gingivalis without inhibiting its adhesion. In vitro cytocompatibility tests also confirmed that adhesion at later phase and proliferation of HGFs were greater (P<0.01) on the GL13K-modified microgroove surfaces than on the non-treated microgroove surfaces, and both of them were greater than on the smooth surfaces. The phenomenon of the contact guidance, which is cell growth aligned along the microgrooves, was maintained. Overall, this study developed a promising bi-functional surface that combined the physical and chemical properties to promote cytocompatibility and antibacterial activity simultaneously.

  6. Remarkable in vitro bactericidal activity of bismuth(III) sulfonates against Helicobacter pylori.

    PubMed

    Andrews, Philip C; Busse, Madleen; Deacon, Glen B; Ferrero, Richard L; Junk, Peter C; MacLellan, Jonathan G; Vom, Amelia

    2012-10-14

    Four new tris-substituted bismuth(III) sulfonates of general formula [Bi(O(3)SR)(3)] (R = phenyl 1, p-tolyl 2, 2,4,6-mesityl 3 and S-(+)-10-camphoryl 4) have been synthesised and characterised. Their synthesis by solvent-free (SF) and solvent-mediated (SM) methods has been explored and their activity against Helicobacter pylori has been investigated. The compounds 1-4 display a remarkable in vitro activity against three laboratory strains of H. pylori (B128, 26,695 and 251) with minimum inhibitory concentration (MIC) values as low as 0.049 μg mL(-1) for the strains B128 and 26,695, and 0.781 μg mL(-1) for the clinical isolate 251. This places most MIC values in the nano-molar region and demonstrates the strong influence of the sulfonate group on the bactericidal properties. The novel solid state structure [Bi(8)(O(3)SMes)(20)(SO(4))(2)(H(2)O)(6)]·(C(7)H(8))(7)5·(C(7)H(8))(7), derived from the SM reaction under reflux conditions, is presented and the incorporation of the two inorganic sulfate anions in the centre of the wheel-like bismuth sulfonate cluster explained.

  7. Biosynthesis and recovery of rod-shaped tellurium nanoparticles and their bactericidal activities

    SciTech Connect

    Zare, Bijan; Faramarzi, Mohammad Ali; Sepehrizadeh, Zargham; Shakibaie, Mojtaba; Rezaie, Sassan; Shahverdi, Ahmad Reza

    2012-11-15

    Highlights: ► Biosynthesis of rod shape tellurium nanoparticles with a hexagonal crystal structure. ► Extraction procedure for isolation of tellurium nanoparticles from Bacillus sp. BZ. ► Extracted tellurium nanoparticles have good bactericidal activity against some bacteria. -- Abstract: In this study, a tellurium-transforming Bacillus sp. BZ was isolated from the Caspian Sea in northern Iran. The isolate was identified by various tests and 16S rDNA analysis, and then used to prepare elemental tellurium nanoparticles. The isolate was subsequently used for the intracellular biosynthesis of elemental tellurium nanoparticles. The biogenic nanoparticles were released by liquid nitrogen and purified by an n-octyl alcohol water extraction system. The shape, size, and composition of the extracted nanoparticles were characterized. The transmission electron micrograph showed rod-shaped nanoparticles with dimensions of about 20 nm × 180 nm. The energy dispersive X-ray and X-ray diffraction spectra respectively demonstrated that the extracted nanoparticles consisted of only tellurium and have a hexagonal crystal structure. This is the first study to demonstrate a biological method for synthesizing rod-shaped elemental tellurium by a Bacillus sp., its extraction and its antibacterial activity against different clinical isolates.

  8. Cathelicidin Antimicrobial Peptides with Reduced Activation of Toll-Like Receptor Signaling Have Potent Bactericidal Activity against Colistin-Resistant Bacteria

    PubMed Central

    Lin, Xiaoyan; Yi, Guanghui; Zhang, Yunliang; Rowe-Magnus, Dean A.; Bush, Karen

    2016-01-01

    ABSTRACT The world is at the precipice of a postantibiotic era in which medical procedures and minor injuries can result in bacterial infections that are no longer effectively treated by antibiotics. Cathelicidins are peptides produced by animals to combat bacterial infections and to regulate innate immune responses. However, cathelicidins are potent activators of the inflammatory response. Cathelicidins with reduced proinflammatory activity and potent bactericidal activity in the low micromolar range against Gram-negative bacteria have been identified. Motifs in cathelicidins that impact bactericidal activity and cytotoxicity to human cells have been elucidated and used to generate peptides that have reduced activation of proinflammatory cytokine production and reduced cytotoxicity to human cells. The resultant peptides have bactericidal activities comparable to that of colistin and can kill colistin-resistant bacteria. PMID:27651360

  9. Bactericidal activity of lemon juice and lemon derivatives against Vibrio cholerae.

    PubMed

    de Castillo, M C; de Allori, C G; de Gutierrez, R C; de Saab, O A; de Fernandez, N P; de Ruiz, C S; Holgado, A P; de Nader, O M

    2000-10-01

    Food products can be possible vectors of the agent responsible for cholera epidemics, because some of these products allow Vibrio cholerae O1 to develop to concentrations above the dangerous level. This study deals with the behaviour of essential oils, natural and concentrated lemon juice and fresh and dehydrated lemon peel against V. cholerae O1 biotype Eltor serotype Inaba tox+. Our aim was to evaluate whether these products, used at different dilutions, exhibit bactericidal or bacteriostatic activity against the microorganism, when present at concentrations of 10(2), 10(4), 10(6) and 10(8) colony forming units (CFU) ml(-1), and after different exposure times. 10(8) CFU ml(-1) was considered an infectious dose. Concentrated lemon juice and essential oils inhibited V. cholerae completely at all studied dilutions and exposure times. Fresh lemon peel and dehydrated lemon peel partially inhibited growth of V. cholerae. Freshly squeezed lemon juice, diluted to 10(-2), showed complete inhibition of V. cholerae at a concentration of 10(8) CFU ml(-1) after 5 min of exposure time; a dilution of 2 x 10(-3) produced inhibition after 15 min and a dilution of 10(-3) after 30 min. It can be concluded that lemon, a natural product which is easily obtained, acts as a biocide against V. cholerae, and is, therefore, an efficient decontaminant, harmless to humans.

  10. Interaction of iodine with 2-hydroxypropyl-alpha-cyclodextrin and its bactericidal activity.

    PubMed

    Tomono, K; Goto, H; Suzuki, T; Ueda, H; Nagai, T; Watanabe, J

    2002-11-01

    To obtain an effective iodine solution, the use of 2-hydroxypropyl-alpha-cyclodextrin (2-HP-alpha-CD) as solubilizer was examined in comparison with alpha-cyclodextrin (alpha-CD), beta-cyclodextrin (beta-CD), potassium iodide (KI), and polyvinylpyrrolidone (PVP). The stability constants for inclusion of iodine with cyclodextrin and KI were ascertained by the solubility method. The apparent stability constants increased in the following order: KI < beta-CD < alpha-CD < 2-HP-alpha-CD. This order was nearly in accordance with that of the stabilization ability. The largest volatile depression effect was exhibited by 2HP-alpha-CD. The measurement of the minimum inhibitory concentration (MC) using Escherichia coli NIH-J-2 and Staphylococcus aureus FDA209P suggested that the bactericidal activity of the iodine/2-HP-alpha-CD system was the same as that of the iodine/alpha-CD, iodine/beta-CD, and iodine/PVP systems. The present results suggest that the combination of 2-HP-alpha-CD and iodine is useful for a stable and effective iodine solution.

  11. Extent of shielding by counterions determines the bactericidal activity of N,N,N-trimethyl chitosan salts.

    PubMed

    Follmann, Heveline D M; Martins, Alessandro F; Nobre, Thatyane M; Bresolin, Joana D; Cellet, Thelma S P; Valderrama, Patrícia; Correa, Daniel S; Muniz, Edvani C; Oliveira, Osvaldo N

    2016-02-10

    In this study, we show that the bactericidal activity of quaternized chitosans (TMCs) with sulfate, acetate, and halide counterions against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) correlates with the "availability" of N-quaternized groups [-(+)N(CH3)3] in the TMCs backbones. N,N,N-trimethyl chitosan sulfate (TMCS) and N,N,N-trimethyl chitosan acetate (TMCAc) displayed the highest activities, probably due to their delocalized π system. Among TMCs with halide counterions, activity was higher for N,N,N-trimethyl chitosan chloride (TMCCl), whereas N,N,N-trimethyl chitosan iodide (TMCI) and N,N,N-trimethyl chitosan bromide (TMCBr) exhibited lower, similar values to each other. This is consistent with the shielding of -(+)N(CH3)3 groups inferred from chemical shifts for halide counterions in (1)HNMR spectra. We also demonstrate that TMCs with distinct bactericidal activities can be classified according to their vibrational spectra using principal component analysis. Taken together, these physicochemical characterization approaches represent a predictive tool for the bactericidal activity of chitosan derivatives.

  12. Comparison of bactericidal activities of various disinfectants against methicillin-sensitive Staphylococcus aureus and methicillin-resistant Staphylococcus aureus.

    PubMed

    Yasuda, T; Yoshimura, S; Katsuno, Y; Takada, H; Ito, M; Takahashi, M; Yahazaki, F; Iriyama, J; Ishigo, S; Asano, Y

    1993-01-01

    Various disinfectants were compared in terms of the duration of bactericidal activity against methicillin-sensitive Staphylococcus aureus (MSSA), and methicillin-resistant Staphylococcus aureus (MRSA), among S. aureus isolated in our hospital. Strains of S. aureus which showed minimum inhibitory concentrations of cloxacillin of less than 1.56 micrograms/ml and of 3.13 micrograms/ml or higher were designated MSSA and MRSA respectively. There was no difference in sensitivity to disinfectants between MSSA and MRSA. There was a great variation in the duration of bactericidal activity of chlorhexidine gluconate against these species with the majority requiring contact times of between 2 minutes and over 20 minutes. All strains except for one strain of MRSA were killed within 20 seconds after disinfection with benzalkonium chloride. All strains were killed within 20 seconds after disinfection with alkyldiaminoethylglycine hydrochloride or povidone-iodine.

  13. Bactericidal active ingredient in cryopreserved plasma-treated water with the reduced-pH method for plasma disinfection

    NASA Astrophysics Data System (ADS)

    Kitano, Katsuhisa; Ikawa, Satoshi; Nakashima, Yoichi; Tani, Atsushi; Yokoyama, Takashi; Ohshima, Tomoko

    2016-09-01

    For the plasma disinfection of human body, plasma sterilization in liquid is crucial. We found that the plasma-treated water (PTW) has strong bactericidal activity under low pH condition. Physicochemical properties of PTW is discussed based on chemical kinetics. Lower temperature brings longer half-life and the bactericidal activity of PTW can be kept by cryopreservation. High performance PTW, corresponding to the disinfection power of 22 log reduction (B. subtilis spore), can be obtained by special plasma system equipped with cooling device. This is equivalent to 65% H2O2, 14% sodium hypochlorite and 0.33% peracetic acid, which are deadly poison for human. But, it is deactivated soon at higher temperature (4 sec. at body temperature), and toxicity to human body seems low. For dental application, PTW was effective on infected models of human extracted tooth. Although PTW has many chemical components, respective chemical components in PTW were isolated by ion chromatography. In addition to peaks of H2O2, NO2- and NO3-, a specific peak was detected. and only this fraction had bactericidal activity. Purified active ingredient of PTW is the precursor of HOO, and further details will be discussed in the presentation. MEXT (15H03583, 23340176, 25108505). NCCE (23-A-15).

  14. Bactericidal activity against Vibrio cholerae of chemical products used in lemon production in Tucumán, Argentina.

    PubMed

    de Castillo, M C; de Allori, C G; de Gutierrez, R C; de Saab, O A; de Fernandez, N P; de Ruiz, C S; de Ruiz Holgado, A P; de Nader, O M

    1997-09-01

    The present research was set up to verify whether the chemical products used in lemon production (from cultivation until packaging) have a bactericidal or a bacteriostatic ability against Vibrio cholerae O1. The studied products were: copper oxychloride, benomil (a carbamate), active chlorine, sodium-o-phenylphenoate, guazatine (a polyamine mixture), imazalil (an imidazole) and lemon peel. The latter was studied with and without treatment using the above mentioned chemicals. Different dilutions of these products were tried out with varying exposure times against the bacterium V. cholerae Serogroup O1, Biotype E1 Tor, Serotype Inaba. The concentrations of the microorganism ranged from 10(2) to 10(8) CFU ml-1, the latter one being considered an infectious dose. The following results were obtained: 1) active chlorine (chlorinated water) showed bactericidal activity at concentrations of 50, 100 and 200 ppm after 10 min of exposure time, 2) copper oxychloride, sodium-o-phenylphenoate, guazatine and imazalil showed bactericidal activity against V. cholerae at concentrations of 10(2) and 10(4) CFU ml-1, 3) due to the fact that during its cultivation the fruit is successively sprayed with several chemical products, it could be that the result of the successive treatments is superior to the result of a repeated treatment with each of the individual products. This consideration should be taken into account when evaluating the eventual protection of the lemon.

  15. Copper and quaternary ammonium cations exert synergistic bactericidal and antibiofilm activity against Pseudomonas aeruginosa.

    PubMed

    Harrison, Joe J; Turner, Raymond J; Joo, Daniel A; Stan, Michelle A; Chan, Catherine S; Allan, Nick D; Vrionis, Helen A; Olson, Merle E; Ceri, Howard

    2008-08-01

    Biofilms are slimy aggregates of microbes that are likely responsible for many chronic infections as well as for contamination of clinical and industrial environments. Pseudomonas aeruginosa is a prevalent hospital pathogen that is well known for its ability to form biofilms that are recalcitrant to many different antimicrobial treatments. We have devised a high-throughput method for testing combinations of antimicrobials for synergistic activity against biofilms, including those formed by P. aeruginosa. This approach was used to look for changes in biofilm susceptibility to various biocides when these agents were combined with metal ions. This process identified that Cu(2+) works synergistically with quaternary ammonium compounds (QACs; specifically benzalkonium chloride, cetalkonium chloride, cetylpyridinium chloride, myristalkonium chloride, and Polycide) to kill P. aeruginosa biofilms. In some cases, adding Cu(2+) to QACs resulted in a 128-fold decrease in the biofilm minimum bactericidal concentration compared to that for single-agent treatments. In combination, these agents retained broad-spectrum antimicrobial activity that also eradicated biofilms of Escherichia coli, Staphylococcus aureus, Salmonella enterica serovar Cholerasuis, and Pseudomonas fluorescens. To investigate the mechanism of action, isothermal titration calorimetry was used to show that Cu(2+) and QACs do not interact in aqueous solutions, suggesting that each agent exerts microbiological toxicity through independent biochemical routes. Additionally, Cu(2+) and QACs, both alone and in combination, reduced the activity of nitrate reductases, which are enzymes that are important for normal biofilm growth. Collectively, the results of this study indicate that Cu(2+) and QACs are effective combinations of antimicrobials that may be used to kill bacterial biofilms.

  16. Immunoresponsive gene 1 augments bactericidal activity of macrophage-lineage cells by regulating β-oxidation-dependent mitochondrial ROS production.

    PubMed

    Hall, Christopher J; Boyle, Rachel H; Astin, Jonathan W; Flores, Maria Vega; Oehlers, Stefan H; Sanderson, Leslie E; Ellett, Felix; Lieschke, Graham J; Crosier, Kathryn E; Crosier, Philip S

    2013-08-06

    Evidence suggests the bactericidal activity of mitochondria-derived reactive oxygen species (mROS) directly contributes to killing phagocytozed bacteria. Infection-responsive components that regulate this process remain incompletely understood. We describe a role for the mitochondria-localizing enzyme encoded by Immunoresponsive gene 1 (IRG1) during the utilization of fatty acids as a fuel for oxidative phosphorylation (OXPHOS) and associated mROS production. In a zebrafish infection model, infection-responsive expression of zebrafish irg1 is specific to macrophage-lineage cells and is regulated cooperatively by glucocorticoid and JAK/STAT signaling pathways. Irg1-depleted macrophage-lineage cells are impaired in their ability to utilize fatty acids as an energy substrate for OXPHOS-derived mROS production resulting in defective bactericidal activity. Additionally, the requirement for fatty acid β-oxidation during infection-responsive mROS production and bactericidal activity toward intracellular bacteria is conserved in murine macrophages. These results reveal IRG1 as a key component of the immunometabolism axis, connecting infection, cellular metabolism, and macrophage effector function.

  17. A comparative study of the bactericidal activity and daily disinfection housekeeping surfaces by a new portable pulsed UV radiation device.

    PubMed

    Umezawa, Kazuo; Asai, Satomi; Inokuchi, Sadaki; Miyachi, Hayato

    2012-06-01

    Daily cleaning and disinfecting of non-critical surfaces in the patient-care areas are known to reduce the occurrence of health care-associated infections. However, the conventional means for decontamination of housekeeping surfaces of sites of frequent hand contact such as manual disinfection using ethanol wipes are laborious and time-consuming in daily practice. This study evaluated a newly developed portable pulsed ultraviolet (UV) radiation device for its bactericidal activity in comparison with continuous UV-C, and investigated its effect on the labor burden when implemented in a hospital ward. Pseudomonas aeruginosa, Multidrug-resistant P. aeruginosa, Escherichia coli, Acinetobacter baumannii, Amikacin and Ciprofloxacin-resistant A. baumannii, Staphylococcus aureus, Methicillin-resistant S. aureus and Bacillus cereus were irradiated with pulsed UV or continuous UV-C. Pulsed UV and continuous UV-C required 5 and 30 s of irradiation, respectively, to attain bactericidal activity with more than 2Log growth inhibition of all the species. The use of pulsed UV in daily disinfection of housekeeping surfaces reduced the working hours by half in comparison to manual disinfection using ethanol wipes. The new portable pulsed UV radiation device was proven to have a bactericidal activity against critical nosocomial bacteria, including antimicrobial-resistant bacteria after short irradiation, and was thus found to be practical as a method for disinfecting housekeeping surfaces and decreasing the labor burden.

  18. Development of a high-throughput method to evaluate serum bactericidal activity using bacterial ATP measurement as survival readout

    PubMed Central

    Saul, Allan; Rondini, Simona

    2017-01-01

    Serum Bactericidal Activity (SBA) assay is the method of choice to evaluate the complement-mediated functional activity of both infection- and vaccine-induced antibodies. To perform a typical SBA assay, serial dilutions of sera are incubated with target bacterial strains and complement. The conventional SBA assay is based on plating on agar the SBA reaction mix and counting the surviving bacterial colony forming units (CFU) at each serum dilution. Even with automated colony counting, it is labor-intensive, time-consuming and not amenable for large-scale studies. Here, we have developed a luminescence-based SBA (L-SBA) method able to detect surviving bacteria by measuring their ATP. At the end of the SBA reaction, a single commercially available reagent is added to each well of the SBA plate, and the resulting luminescence signal is measured in a microplate reader. The signal obtained is proportional to the ATP present, which is directly proportional to the number of viable bacteria. Bactericidal activity is subsequently calculated. We demonstrated the applicability of L-SBA with multiple bacterial serovars, from 5 species: Citrobacter freundii, Salmonella enterica serovars Typhimurium and Enteritidis, Shigella flexneri serovars 2a and 3a, Shigella sonnei and Neisseria meningitidis. Serum bactericidal titers obtained by the luminescence readout method strongly correlate with the data obtained by the conventional agar plate-based assay, and the new assay is highly reproducible. L-SBA considerably shortens assay time, facilitates data acquisition and analysis and reduces the operator dependency, avoiding the plating and counting of CFUs. Our results demonstrate that L-SBA is a useful high-throughput bactericidal assay. PMID:28192483

  19. Comparative bactericidal activities of ciprofloxacin, clinafloxacin, grepafloxacin, levofloxacin, moxifloxacin, and trovafloxacin against Streptococcus pneumoniae in a dynamic in vitro model.

    PubMed

    Klepser, M E; Ernst, E J; Petzold, C R; Rhomberg, P; Doern, G V

    2001-03-01

    Several new quinolones that exhibit enhanced in vitro activity against Streptococcus pneumoniae have been developed. Using a dynamic in vitro model, we generated time-kill data for ciprofloxacin, clinafloxacin, grepafloxacin, levofloxacin, moxifloxacin, and trovafloxacin against three isolates of quinolone-susceptible S. pneumoniae. Three pharmacokinetic profiles were simulated for each of the study agents (0.1, 1, and 10 times the area under the concentration-time curve [AUC]). Target 24-h AUCs were based upon human pharmacokinetic data resulting from the maximal daily doses of each agent. Ciprofloxacin was the least active agent against all three isolates. With regimens that simulated the human 24-h AUC, ciprofloxacin resulted in an initial, modest decline in the numbers of CFU per milliliter; however, by 48 h the numbers of CFU per milliliter returned to or exceeded the starting inoculum. At the AUC, levofloxacin resulted in variable bacteriostatic and bactericidal activities against the isolates. The remaining agents yielded bactericidal (99.9% reduction) activity by 48 h with regimens that simulated the AUC. At 0.1 time the AUC ciprofloxacin and levofloxacin produced no inhibitory effect, grepafloxacin exhibited bacteriostatic activity, trovafloxacin had mixed static and cidal activities, and clinafloxacin and moxifloxacin caused significant reductions in the numbers of CFU per milliliter by 48 h. All six agents produced cidal activity at 10 times the AUC. In this dynamic in vitro model of infection, the quinolones demonstrated various degrees of activity against S. pneumoniae. The rank order of activity, with respect to bactericidal effect, was ciprofloxacin (least active) < levofloxacin < grepafloxacin, trovafloxacin < clinafloxacin and moxifloxacin (most active). The rank order of the agents with respect to the selection of resistance was ciprofloxacin (most likely) > grepafloxacin, moxifloxacin, and trovafloxacin > levofloxacin > clinafloxacin.

  20. Neutralization of bactericidal activity related to antimicrobial carry-over in broiler carcass rinse samples

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Chemical antimicrobial interventions used as poultry processing aids may have potential for carry-over into whole poultry carcass buffered peptone water (BPW) rinses collected for the recovery of viable Salmonella. Such carry-over may lead to false negative indications due to continuing bactericidal...

  1. Bactericidal activity of lauric arginate in milk and Queso Fresco cheese against Listeria monocytogenes cold growth.

    PubMed

    Soni, K A; Nannapaneni, R; Schilling, M W; Jackson, V

    2010-10-01

    Lauric arginate (LAE) at concentrations of 200 ppm and 800 ppm was evaluated for its effectiveness in reducing cold growth of Listeria monocytogenes in whole milk, skim milk, and Queso Fresco cheese (QFC) at 4°C for 15 to 28 d. Use of 200 ppm of LAE reduced 4 log cfu/mL of L. monocytogenes to a nondetectable level within 30 min at 4°C in tryptic soy broth. In contrast, when 4 log cfu/mL of L. monocytogenes was inoculated in whole milk or skim milk, the reduction of L. monocytogenes was approximately 1 log cfu/mL after 24 h with 200 ppm of LAE. When 800 ppm of LAE was added to whole or skim milk, the initial 4 log cfu/mL of L. monocytogenes was nondetectable following 24 h, and no growth of L. monocytogenes was observed for 15 d at 4°C. With surface treatment of 200 or 800 ppm of LAE on vacuum-packaged QFC, the reductions of L. monocytogenes within 24 h at 4°C were 1.2 and 3.0 log cfu/g, respectively. In addition, the overall growth of L. monocytogenes in QFC was decreased by 0.3 to 2.6 and by 2.3 to 5.0 log cfu/g with 200 and 800 ppm of LAE, respectively, compared with untreated controls over 28 d at 4°C. Sensory tests revealed that consumers could not determine a difference between QFC samples that were treated with 0 and 200 ppm of LAE, the FDA-approved level of LAE use in foods. In addition, no differences existed between treatments with respect to flavor, texture, and overall acceptability of the QFC. Lauric arginate shows promise for potential use in QFC because it exerts initial bactericidal activity against L. monocytogenes at 4°C without affecting sensory quality.

  2. Algerian propolis extracts: Chemical composition, bactericidal activity and in vitro effects on gilthead seabream innate immune responses.

    PubMed

    Soltani, El-Khamsa; Cerezuela, Rebeca; Charef, Noureddine; Mezaache-Aichour, Samia; Esteban, Maria Angeles; Zerroug, Mohamed Mihoub

    2017-03-01

    Propolis has been used as a medicinal agent for centuries. The chemical composition of four propolis samples collected from four locations of the Sétif region, Algeria, using gas chromatography-mass spectrometry was determined. More than 20 compounds and from 30 to 35 compounds were identified in the aqueous and ethanolic extracts, respectively. Furthermore, the antimicrobial activity of the propolis extracts against two marine pathogenic bacteria was evaluated. Finally, the in vitro effects of propolis on gilthead seabream (Sparus aurata L.) leucocyte activities were measured. The bactericidal activity of ethanolic extracts was very high against Shewanella putrefaciens, average against Photobacterium damselae and very low against Vibrio harveyi. The lowest bactericidal activity was always that found for the aqueous extracts. When the viability of gilthead seabream head-kidney leucocytes was measured after 30 min' incubation with the different extracts, both the ethanolic and aqueous extracts of one of the propolis samples (from Babor) and the aqueous extract of another (from Ain-Abbassa) provoked a significant decrease in cell viability when used at concentrations of 100 and 200 μg ml(-1). Furthermore, significant inhibitory effects were recorded on leucocyte respiratory burst activity when isolated leucocytes where preincubated with the extracts. This effect was dose-dependent in all cases except when extracts from a third propolis sample (from Boutaleb) were used. Our findings suggest that some of Algerian propolis extracts have bactericidal activity against important bacterial pathogens in seabream and significantly modulate in vitro leucocyte activities, confirming their potential as a source of new natural biocides and/or immunomodulators in aquaculture practice.

  3. Bactericidal Activity of Ceragenin CSA-13 in Cell Culture and in an Animal Model of Peritoneal Infection

    PubMed Central

    Niemirowicz, Katarzyna; Wnorowska, Urszula; Byfield, Fitzroy J.; Piktel, Ewelina; Wątek, Marzena; Janmey, Paul A.; Savage, Paul B.

    2015-01-01

    Ceragenins constitute a novel family of cationic antibiotics characterized by a broad spectrum of antimicrobial activities, which have mostly been assessed in vitro. Using a polarized human lung epithelial cell culture system, we evaluated the antibacterial activities of the ceragenin CSA-13 against two strains of Pseudomonas aeruginosa (PAO1 and Xen5). Additionally, the biodistribution and bactericidal activity of a CSA-13–IRDye 800CW derivate were assessed using an animal model of peritoneal infection after PAO1 challenge. In cell culture, CSA-13 bactericidal activities against PAO1 and Xen5 were higher than the activities of the human cathelicidin peptide LL-37. Increased CSA-13 activity was observed in polarized human lung epithelial cell cultures subjected to butyric acid treatment, which is known to increase endogenous LL-37 production. Eight hours after intravenous or intraperitoneal injection, the greatest CSA-13–IRDye 800CW accumulation was observed in mouse liver and kidneys. CSA-13–IRDye 800CW administration resulted in decreased bacterial outgrowth from abdominal fluid collected from animals subjected to intraperitoneal PAO1 infection. These observations indicate that CSA-13 may synergistically interact with antibacterial factors that are naturally present at mucosal surfaces and it maintains its antibacterial activity in the infected abdominal cavity. Cationic lipids such as CSA-13 represent excellent candidates for the development of new antibacterial compounds. PMID:26248361

  4. Docosahexaenoic acid loaded lipid nanoparticles with bactericidal activity against Helicobacter pylori.

    PubMed

    Seabra, Catarina Leal; Nunes, Cláudia; Gomez-Lazaro, Maria; Correia, Marta; Machado, José Carlos; Gonçalves, Inês C; Reis, Celso A; Reis, Salette; Martins, M Cristina L

    2017-03-15

    Docosahexaenoic acid (DHA), an omega-3 polyunsaturated fatty acid present in fish oil, has been described as a promising molecule to the treatment of Helicobacter pylori gastric infection. However, due to its highly unsaturated structure, DHA can be easily oxidized loosing part of its bioactivity. This work aims the nanoencapsulation of DHA to improve its bactericidal efficacy against H. pylori. DHA was loaded into nanostructured lipid carriers (NLC) produced by hot homogenization and ultrasonication using a blend of lipids (Precirol ATO5(®), Miglyol-812(®)) and a surfactant (Tween 60(®)). Homogeneous NLC with 302±14nm diameter, -28±3mV surface charge (dynamic and electrophoretic light scattering) and containing 66±7% DHA (UV/VIS spectroscopy) were successfully produced. Bacterial growth curves, performed over 24h in the presence of different DHA concentrations (free or loaded into NLC), demonstrated that nanoencapsulation enhanced DHA bactericidal effect, since DHA-loaded NLC were able to inhibit H. pylori growth in a much lower concentrations (25μM) than free DHA (>100μM). Bioimaging studies, using scanning and transmission electron microscopy and also imaging flow cytometry, demonstrated that DHA-loaded NLC interact with H. pylori membrane, increasing their periplasmic space and disrupting membrane and allowing the leakage of cytoplasmic content. Furthermore, the developed nanoparticles are not cytotoxic to human gastric adenocarcinoma cells at bactericidal concentrations. DHA-loaded NLC should, therefore, be envisaged as an alternative to the current treatments for H. pylori infection.

  5. Influence of Scaffold Size on Bactericidal Activity of Nitric Oxide Releasing Silica Nanoparticles

    PubMed Central

    Carpenter, Alexis W.; Slomberg, Danielle L.; Rao, Kavitha S.; Schoenfisch, Mark H.

    2011-01-01

    A reverse microemulsion synthesis was used to prepare amine functionalized silica nanoparticles of three distinct sizes (i.e., 50, 100, and 200 nm) with identical amine concentrations. The resulting hybrid nanoparticles, consisting of N-(6 aminohexyl) aminopropyltrimethoxysilane and tetraethoxysilane, were highly monodisperse in size. N-diazeniumdiolate nitric oxide (NO) donors were subsequently formed on secondary amines while controlling reaction conditions to keep the total amount of nitric oxide (NO) released constant for each particle size. The bactericidal efficacy of the NO releasing nanoparticles against Pseudomonas aeruginosa increased with decreasing particle size. Additionally, smaller diameter nanoparticles were found to associate with the bacteria at a faster rate and to a greater extent than larger particles. Neither control (non-NO-releasing) nor NO releasing particles exhibited toxicity towards L929 mouse fibroblasts at concentrations above their respective minimum bactericidal concentrations. This study represents the first investigation of the bactericidal efficacy of NO-releasing silica nanoparticles as a function of particle size. PMID:21842899

  6. Bactericidal activities of cathelicidin LL-37 and select cationic lipids against the hypervirulent Pseudomonas aeruginosa strain LESB58.

    PubMed

    Wnorowska, Urszula; Niemirowicz, Katarzyna; Myint, Melissa; Diamond, Scott L; Wróblewska, Marta; Savage, Paul B; Janmey, Paul A; Bucki, Robert

    2015-07-01

    Pseudomonas aeruginosa Liverpool epidemic strain (LES) infections in cystic fibrosis (CF) patients are associated with transmissibility and increased patient morbidity. This study was designed to assess the in vitro activities of cathelicidin LL-37 peptide (LL-37) and select cationic lipids against Pseudomonas aeruginosa LESB58 in CF sputum and in a setting mimicking the CF airway. We found that LL-37 naturally present in airway surface fluid and some nonpeptide cationic lipid molecules such as CSA-13, CSA-90, CSA-131, and D2S have significant, but broadly differing, bactericidal activities against P. aeruginosa LESB58. We observed strong inhibition of LL-37 bactericidal activity in the presence of purified bacteriophage Pf1, which is highly expressed by P. aeruginosa LES, but the activities of the cationic lipids CSA-13 and CSA-131 were not affected by this polyanionic virus. Additionally, CSA-13 and CSA-131 effectively prevent LESB58 biofilm formation, which is stimulated by Pf1 bacteriophage, DNA, or F-actin. CSA-13 and CSA-131 display strong antibacterial activities against different clinical strains of P. aeruginosa, and their activities against P. aeruginosa LESB58 and Xen5 strains were maintained in CF sputum. These data indicate that synthetic cationic lipids (mimics of natural antimicrobial peptides) are suitable for developing an effective treatment against CF lung P. aeruginosa infections, including those caused by LES strains.

  7. Bactericidal Activities of Cathelicidin LL-37 and Select Cationic Lipids against the Hypervirulent Pseudomonas aeruginosa Strain LESB58

    PubMed Central

    Wnorowska, Urszula; Niemirowicz, Katarzyna; Myint, Melissa; Diamond, Scott L.; Wróblewska, Marta; Savage, Paul B.; Janmey, Paul A.

    2015-01-01

    Pseudomonas aeruginosa Liverpool epidemic strain (LES) infections in cystic fibrosis (CF) patients are associated with transmissibility and increased patient morbidity. This study was designed to assess the in vitro activities of cathelicidin LL-37 peptide (LL-37) and select cationic lipids against Pseudomonas aeruginosa LESB58 in CF sputum and in a setting mimicking the CF airway. We found that LL-37 naturally present in airway surface fluid and some nonpeptide cationic lipid molecules such as CSA-13, CSA-90, CSA-131, and D2S have significant, but broadly differing, bactericidal activities against P. aeruginosa LESB58. We observed strong inhibition of LL-37 bactericidal activity in the presence of purified bacteriophage Pf1, which is highly expressed by P. aeruginosa LES, but the activities of the cationic lipids CSA-13 and CSA-131 were not affected by this polyanionic virus. Additionally, CSA-13 and CSA-131 effectively prevent LESB58 biofilm formation, which is stimulated by Pf1 bacteriophage, DNA, or F-actin. CSA-13 and CSA-131 display strong antibacterial activities against different clinical strains of P. aeruginosa, and their activities against P. aeruginosa LESB58 and Xen5 strains were maintained in CF sputum. These data indicate that synthetic cationic lipids (mimics of natural antimicrobial peptides) are suitable for developing an effective treatment against CF lung P. aeruginosa infections, including those caused by LES strains. PMID:25870055

  8. Immunoregulation by macrophages II. Separation of mouse peritoneal macrophages having tumoricidal and bactericidal activities and those secreting PGE and interleukin I

    SciTech Connect

    Hopper, K.E.; Cahill, J.M.

    1983-06-01

    Macrophage subpopulations having bactericidal or tumoricidal activities and secreting interleukin I (IL1) or prostaglandin E (PGE) were identified through primary or secondary infection with Salmonella enteritidis and separated by sedimentation velocity. Bactericidal activity was measured by (3H)-thymidine release from Listeria monocytogenes and tumoricidal activity by 51Cr-release from C-4 fibrosarcoma or P815 mastocytoma cells. Macrophages with bactericidal activity were distinguished from those with tumoricidal activity a) during secondary infection when cytolytic activity occurred only at days 1-4 post injection and bactericidal activity remained high throughout and b) after sedimentation velocity separation. Cytolysis was consistently greatest among adherent cells of low sedimentation velocity, whereas cells with bactericidal activity increased in size during the infection. Tumour cytostasis (inhibition and promotion of (3H)-thymidine uptake) differed from cytolysis in that the former was more prolonged during infection and was also detected among large cells. Secretion of immunoregulatory molecules PGE and IL1 occurred maximally among different macrophage subpopulations separated by sedimentation velocity and depending on the type of stimulus used in vitro. There was an inverse correlation between IL1 production and PGE production after stimulation with C3-zymosan or lipopolysaccharide (LPS). The development of immunity during infection may therefore be dependent upon the relative proportions of effector and regulatory macrophage subpopulations and the selective effects of environmental stimuli on these functions.

  9. Bactericidal activity of cefoperazone with CP-45,899 against large inocula of beta-lactamase-producing Haemophilus influenzae.

    PubMed Central

    Yu, P K; Washington, J A

    1981-01-01

    Bactericidal activity of cefoperazone, alone and in combination with the beta-lactamase inhibitor CP-45,899, was tested against inocula of 10(7) colony-forming units of beta-lactamase-producing isolates of Haemophilus influenzae type b per ml. Of 19 strains tested, 10 required greater than or equal to 64 microgram of cefoperazone per ml for killing, whereas no strains were killed by less than 64 microgram of CP-45,899 per ml. Synergy occurred with the combination of 4 microgram of each agent per ml against 9 of the 10 cefoperazone-resistant strains. PMID:6269484

  10. Preparation of AgBr@SiO2 core@shell hybrid nanoparticles and their bactericidal activity.

    PubMed

    Li, Yuanyuan; Yang, Lisu; Zhao, Yanbao; Li, Binjie; Sun, Lei; Luo, Huajuan

    2013-04-01

    AgBr@SiO2 core@shell hybrid nanoparticles (NPs) were successfully prepared by sol-gel method. Their morphology and structure were characterized by transmission electron microscopy (TEM) and X-ray diffraction (XRD). The hybrid NPs are predominantly spherical in shape, with an average diameter of 180-200 nm, and each NP contains one inorganic core. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of the hybrid NPs were examined against Staphylococcus aureus (S. aureus), Pseudomonas aeruginosa (P. aeruginosa) and Escherichia coli (E. coli), respectively. Results indicated that the AgBr@SiO2 NPs had excellent antibacterial activity.

  11. In vitro sensitivity of oral, gram-negative, facultative bacteria to the bactericidal activity of human neutrophil defensins.

    PubMed Central

    Miyasaki, K T; Bodeau, A L; Ganz, T; Selsted, M E; Lehrer, R I

    1990-01-01

    Neutrophils play a major role in defending the periodontium against infection by oral, gram-negative, facultative bacteria, such as Actinobacillus actinomycetemcomitans, Eikenella corrodens, and Capnocytophaga spp. We examined the sensitivity of these bacteria to a mixture of low-molecular-weight peptides and highly purified individual defensin peptides (HNP-1, HNP-2, and HNP-3) isolated from human neutrophils. Whereas the Capnocytophaga spp. strains were killed significantly by the mixed human neutrophil peptides, the A. actinomycetemcomitans and E. corrodens strains were resistant. Killing was attributable to the defensins. The bactericidal activities of purified defensins HNP-1 and HNP-2 were equal, and both of these activities were greater than HNP-3 activity against strains of Capnocytophaga sputigena and Capnocytophaga gingivalis. The strain of Capnocytophaga ochracea was more sensitive to defensin-mediated bactericidal activity than either C. sputigena or C. gingivalis was. The three human defensins were equipotent in killing C. ochracea. C. ochracea was killed under aerobic and anaerobic conditions and over a broad pH range. Killing was most effective under hypotonic conditions but also occurred at physiologic salt concentrations. We concluded that Capnocytophaga spp. are sensitive to oxygen-independent killing by human defensins. Additional studies will be required to identify other components that may equip human neutrophils to kill A. actinomycetemcomitans, E. corrodens, and other oral gram-negative bacteria. Images PMID:2254020

  12. Effect of food processing organic matter on photocatalytic bactericidal activity of titanium dioxide (TiO2).

    PubMed

    Yemmireddy, Veerachandra K; Hung, Yen-Con

    2015-07-02

    The purpose of this study was to determine the effect of food processing organic matter on photocatalytic bactericidal activity of titanium dioxide (TiO2) nanoparticles (NPs). Produce and meat processing wash solutions were prepared using romaine lettuce and ground beef samples. Physico-chemical properties such as pH, turbidity, chemical oxygen demand (COD), total phenolics (for produce) and protein (for meat) content of the extracts were determined using standard procedures. The photocatalytic bactericidal activity of TiO2 (1 mg/mL) in suspension with or without organic matter against Escherichia coli O157:H7 (5-strain) was determined over a period of 3h. Increasing the concentration of organic matter (either produce or meat) from 0% to 100% resulted in 85% decrease in TiO2 microbicidal efficacy. 'Turbidity, total phenolics, and protein contents in wash solutions had significant effect on the log reduction. Increasing the total phenolics content in produce washes from 20 to 114 mg/L decreased the log reduction from 2.7 to 0.38 CFU/mL, whereas increasing the protein content in meat washes from 0.12 to 1.61 mg/L decreased the log reduction from and 5.74 to 0.87 CFU/mL. Also, a linear correlation was observed between COD and total phenolics as well as COD and protein contents. While classical disinfection kinetic models failed to predict, an empirical equation in the form of "Y=me(nX)" (where Y is log reduction, X is COD, and m and n are reaction rate constants) predicted the disinfection kinetics of TiO2 in the presence of organic matter (R(2)=94.4). This study successfully identified an empirical model with COD as a predictor variable to predict the bactericidal efficacy of TiO2 when used in food processing environment.

  13. Bactericidal activities of BMS-284756, a novel Des-F(6)-quinolone, against Staphylococcus aureus strains with topoisomerase mutations.

    PubMed

    Lawrence, Laura E; Frosco, MaryBeth; Ryan, Brenda; Chaniewski, Susan; Yang, Hyekyung; Hooper, David C; Barrett, John F

    2002-01-01

    The antistaphylococcal activities of BMS-284756 (T-3811ME), levofloxacin, moxifloxacin, and ciprofloxacin were compared against wild-type and grlA and grlA/gyrA mutant strains of Staphylococcus aureus. BMS-284756 was the most active quinolone tested, with MICs and minimal bactericidal concentrations against S. aureus wild-type strain MT5, grlA mutant MT5224c4, and grlA/gyrA mutant EN8 of 0.03 and 0.06, 0.125 and 0.125, and 4 and 4 microg/ml, respectively. In the time-kill studies, BMS-284756 and levofloxacin exhibited rapid killing against all strains. Ciprofloxacin, however, was not bactericidal for the double mutant, EN8. BMS-284756 and levofloxacin were bactericidal (3 log(10) decrease in CFU/ml) against the MT5 and MT5224c4 strains at two and four times the MIC within 2 to 4 h. Against EN8, BMS-284756 was bactericidal within 4 h at two and four times the MIC, and levofloxacin achieved similar results within 4 to 6 h. Both the wild-type strain MT5 and grlA mutant MT5224c4 should be considered susceptible to both BMS-284756 and levofloxacin, and both quinolones are predicted to have clinical efficacy. The in vivo efficacy of BMS-284756, levofloxacin, and moxifloxacin against S. aureus strain ISP794 and its single mutant 2C6(1)-1 directly reflected the in vitro activity: increased MICs correlated with decreased in vivo efficacy. The 50% protective doses of BMS-284756 against wild-type and mutant strains were 2.2 and 1.6 mg/kg of body weight/day, respectively, compared to the levofloxacin values of 16 and 71 mg/kg/day and moxifloxacin values of 4.7 and 61.6 mg/kg/day. BMS-284756 was more potent than levofloxacin and equipotent with moxifloxacin against ISP794 both in vitro and in vivo, while BMS-284756 was more potent than levofloxacin and moxifloxacin against 2C6(1)-1.

  14. Verapamil increases the bactericidal activity of bedaquiline against Mycobacterium tuberculosis in a mouse model.

    PubMed

    Gupta, Shashank; Tyagi, Sandeep; Bishai, William R

    2015-01-01

    Bedaquiline is a newly approved drug for the treatment of multidrug-resistant tuberculosis, but there are concerns about its safety in humans. We found that the coadministration of verapamil with subinhibitory doses of bedaquiline gave the same bactericidal effect in mice as did the full human bioequivalent bedaquiline dosing. Adding verapamil to bedaquiline monotherapy also protected against the development of resistant mutants in vivo. The adjunctive use of verapamil may permit use of lower doses of bedaquiline to be used and thereby reduce its dose-related toxicities in tuberculosis patients.

  15. Peroxiredoxin-6 Negatively Regulates Bactericidal Activity and NF-κB Activity by Interrupting TRAF6-ECSIT Complex

    PubMed Central

    Min, Yoon; Wi, Sae M.; Shin, Dongwoo; Chun, Eunyoung; Lee, Ki-Young

    2017-01-01

    A TRAF6-ECSIT complex is crucial for the generation of mitochondrial reactive oxygen species (mROS) and nuclear factor-kappa B (NF-κB) activation induced by Toll-like receptor 4 (TLR4). Peroxiredoxin-6 (Prdx6) as a member of the peroxiredoxin family of antioxidant enzymes is involved in antioxidant protection and cell signaling. Here, we report on a regulatory role of Prdx6 in mROS production and NF-κB activation by TLR4. Prdx6 was translocated into the mitochondria by TLR4 stimulation and Prdx6-knockdown (Prdx6KD) THP-1 cells had increased level of mitochondrial reactive oxygen species levels and were resistant to Salmonella typhimurium infection. Biochemical studies revealed Prdx6 interaction with the C-terminal TRAF-C domain of TRAF6, which drove translocation into the mitochondria. Interestingly, Prdx6 competitively interacted with ECSIT to TRAF6 through its C-terminal TRAF-C domain, leading to the interruption of TRAF6-ECSIT interaction. The inhibitory effect was critically implicated in the activation of NF-κB induced by TLR4. Overexpression of Prdx6 led to the inhibition of NF-κB induced by TLR4, whereas Prdx6KD THP-1 cells displayed enhanced production of pro-inflammatory cytokines including interleukin-6 and -1β, and the up-regulation of NF-κB-dependent genes induced by TLR4 stimulation. Taken together, the data demonstrate that Prdx6 interrupts the formation of TRAF6-ECSIT complex induced by TLR4 stimulation, leading to suppression of bactericidal activity because of inhibited mROS production in mitochondria and the inhibition of NF-κB activation in the cytoplasm. PMID:28393051

  16. An investigation of the bactericidal activity of selected essential oils to Aeromonas spp.

    USGS Publications Warehouse

    Starliper, Clifford E.; Ketolab, Henry G.; Noyes, Andrew D.; Schill, William B.; Henson, Fred G.; Chalupnicki, Marc A.; Dittman, Dawn E.

    2015-01-01

    Diseases of fishes caused by Aeromonas spp. are common, have broad host ranges and may cause high mortality. Treatments for captive-reared populations using antimicrobials are limited with concerns for bacterial resistance development and environmental dissemination. This study was done to determine if selected plant-derived essential oils were bactericidal to Aeromonas spp. Initially, twelve essential oils were evaluated using a disk diffusion assay to an isolate of A. salmonicida subsp. salmonicida, cause of fish furunculosis. The greatest zones of inhibition were obtained with oils of cinnamon Cinnamomum cassia, oregano Origanum vulgare, lemongrass Cymbopogon citratus and thyme Thymus vulgaris. Minimum bactericidal concentrations (MBC’s) were determined for these four oils, Allimed® (garlic extract, Allium sativum) and colloidal silver to sixty-nine isolates representing nine Aeromonas spp. The lowest mean MBC’s (0.02 to 0.04%) were obtained with three different sources of cinnamon oil. MBC’s for three sources of oregano and lemongrass oils ranged from 0.14 to 0.30% and 0.10 to 0.65%, respectively, and for two thyme oils were 2.11 and 2.22%. The highest concentration (5%) of Allimed® tested resulted in MBC’s to twelve isolates. A concentration of silver greater than 15 mg/L would be required to determine MBC’s for all but one isolate

  17. An investigation of the bactericidal activity of selected essential oils to Aeromonas spp.

    USGS Publications Warehouse

    Starliper, Clifford E.; Ketola, H. George; Noyes, Andrew D.; Schill, William B.; Henson, Fred G.; Chalupnicki, Marc; Dittman, Dawn E.

    2015-01-01

    Diseases of fishes caused by Aeromonas spp. are common, have broad host ranges and may cause high mortality. Treatments of captive-reared populations using antimicrobials are limited with concerns for bacterial resistance development and environmental dissemination. This study was done to determine whether selected plant-derived essential oils were bactericidal to Aeromonas spp. Initially, twelve essential oils were evaluated using a disk diffusion assay to an isolate of A. salmonicida subsp. salmonicida, cause of fish furunculosis. The greatest zones of inhibition were obtained with oils of cinnamon Cinnamomum cassia, oregano Origanum vulgare, lemongrass Cymbopogon citratus and thyme Thymus vulgaris. Minimum bactericidal concentrations (MBC’s) were determined for these four oils, Allimed® (garlic extract, Allium sativum) and colloidal silver to sixty-nine isolates representing nine Aeromonas spp. The lowest mean MBCs (0.02–0.04%) were obtained with three different sources of cinnamon oil. MBCs for three sources of oregano and lemongrass oils ranged from 0.14% to 0.30% and 0.10% to 0.65%, respectively, and for two thyme oils were 2.11% and 2.22%. The highest concentration (5%) of Allimed® tested resulted in MBCs to twelve isolates. A concentration of silver greater than 15 mg/L would be required to determine MBCs for all but one isolate.

  18. An investigation of the bactericidal activity of selected essential oils to Aeromonas spp.

    PubMed

    Starliper, Clifford E; Ketola, Henry G; Noyes, Andrew D; Schill, William B; Henson, Fred G; Chalupnicki, Marc A; Dittman, Dawn E

    2015-01-01

    Diseases of fishes caused by Aeromonas spp. are common, have broad host ranges and may cause high mortality. Treatments of captive-reared populations using antimicrobials are limited with concerns for bacterial resistance development and environmental dissemination. This study was done to determine whether selected plant-derived essential oils were bactericidal to Aeromonas spp. Initially, twelve essential oils were evaluated using a disk diffusion assay to an isolate of A. salmonicida subsp. salmonicida, cause of fish furunculosis. The greatest zones of inhibition were obtained with oils of cinnamon Cinnamomum cassia, oregano Origanum vulgare, lemongrass Cymbopogon citratus and thyme Thymus vulgaris. Minimum bactericidal concentrations (MBC's) were determined for these four oils, Allimed® (garlic extract, Allium sativum) and colloidal silver to sixty-nine isolates representing nine Aeromonas spp. The lowest mean MBCs (0.02-0.04%) were obtained with three different sources of cinnamon oil. MBCs for three sources of oregano and lemongrass oils ranged from 0.14% to 0.30% and 0.10% to 0.65%, respectively, and for two thyme oils were 2.11% and 2.22%. The highest concentration (5%) of Allimed® tested resulted in MBCs to twelve isolates. A concentration of silver greater than 15 mg/L would be required to determine MBCs for all but one isolate.

  19. An investigation of the bactericidal activity of selected essential oils to Aeromonas spp.

    PubMed Central

    Starliper, Clifford E.; Ketola, Henry G.; Noyes, Andrew D.; Schill, William B.; Henson, Fred G.; Chalupnicki, Marc A.; Dittman, Dawn E.

    2014-01-01

    Diseases of fishes caused by Aeromonas spp. are common, have broad host ranges and may cause high mortality. Treatments of captive-reared populations using antimicrobials are limited with concerns for bacterial resistance development and environmental dissemination. This study was done to determine whether selected plant-derived essential oils were bactericidal to Aeromonas spp. Initially, twelve essential oils were evaluated using a disk diffusion assay to an isolate of A. salmonicida subsp. salmonicida, cause of fish furunculosis. The greatest zones of inhibition were obtained with oils of cinnamon Cinnamomum cassia, oregano Origanum vulgare, lemongrass Cymbopogon citratus and thyme Thymus vulgaris. Minimum bactericidal concentrations (MBC’s) were determined for these four oils, Allimed® (garlic extract, Allium sativum) and colloidal silver to sixty-nine isolates representing nine Aeromonas spp. The lowest mean MBCs (0.02–0.04%) were obtained with three different sources of cinnamon oil. MBCs for three sources of oregano and lemongrass oils ranged from 0.14% to 0.30% and 0.10% to 0.65%, respectively, and for two thyme oils were 2.11% and 2.22%. The highest concentration (5%) of Allimed® tested resulted in MBCs to twelve isolates. A concentration of silver greater than 15 mg/L would be required to determine MBCs for all but one isolate. PMID:25685547

  20. In vitro study of the post-antibiotic effect and the bactericidal activity of Cefditoren and ten other oral antimicrobial agents against upper and lower respiratory tract pathogens.

    PubMed

    Dubois, J; St-Pierre, C

    2000-07-01

    The in vitro post-antibiotic effect (PAE) and batericidal activity of cefditoren was compared to that of cefixime, cefuroxime, loracarbef, cefaclor, amoxicillin, amoxicillin/clavulanate, clarithromycin, azithromycin, erythromycin, and ciprofloxacin against ATCC culture strains and clinical respiratory isolates. A PAE > 1 h was observed for cefditoren and generally for the macrolides against Streptococcus pneumoniae, beta-lactamase-negative Moraxella catarrhalis, and Streptococcus pyogenes, whereas the other beta-lactams showed mixed results. Cefditoren was the only beta-lactam showing significant bactericidal activity (>3 log reduction of viable cells) within 4 h against penicillin-resistant S. pneumoniae. Only cefditoren and ciprofloxacin showed significant bactericidal activity against beta-lactamase-negative (after 24 h) and beta-lactamase-positive strains of H. influenzae (after 12 h). Against beta-lactamase-positive strains of M. catarrhalis, cefditoren was the only agent to show significant bactericidal activity at 6 h (versus cefuroxime and ciprofloxacin at 12 h).

  1. Cefpodoxime: comparative antibacterial activity, influence of growth conditions, and bactericidal activity.

    PubMed

    Knothe, H; Shah, P M; Eckardt, O

    1991-01-01

    The antimicrobial activity of cefpodoxime, the active metabolite of the new cephalosporin ester cefpodoxime proxetil, in comparison to cefixime, cefotiam, cefuroxime, and cefotaxime was determined against a broad spectrum of freshly isolated gram-positive and gram-negative bacterial strains. Cefpodoxime was demonstrated to be inhibitory at concentrations of less than or equal to 1 mg/l against 90% of strains of Moraxella catarrhalis, Haemophilus influenzae, Escherichia coli (beta-lactamase- negative strains), Klebsiella spp., Serratia spp., Proteus mirabilis, Proteus vulgaris, Providencia spp., and Salmonella spp. This antimicrobial activity of cefpodoxime was generally superior to that of cefuroxime and similar to that of cefixime. Cefpodoxime was active at less than or equal to 1 mg/l against 50% of the members of beta-lactamase-producing Escherichia coli, Enterobacter cloacae, Enterobacter aerogenes, Citrobacter spp., and Morganella morganii. Cefpodoxime proved to be highly inhibitory against group A, B, and G streptococci and Streptococcus pneumoniae (MIC90 less than 0.015 mg/l). The MICs of cefpodoxime and those of the other cephalosporins were less than 2 mg/l for greater than or equal to 90% of the strains of Staphylococcus aureus and Staphylococcus epidermidis, with the exception of cefixime which had no activity with MICs below 8 mg/l against these bacteria. Pseudomonas spp., Acinetobacter spp., and Enterococcus spp. were resistant to cefpodoxime. The antibacterial activity of cefpodoxime was only to a minor degree influenced by different growth conditions with the exception of high inoculum sizes against some beta-lactamase producing strains of gram-negative bacilli.(ABSTRACT TRUNCATED AT 250 WORDS)

  2. Anionic Amino Acids near the Pro-α-defensin N Terminus Mediate Inhibition of Bactericidal Activity in Mouse Pro-cryptdin-4*S⃞

    PubMed Central

    Figueredo, Sharel M.; Weeks, Colby S.; Young, Steven K.; Ouellette, André J.

    2009-01-01

    In mouse Paneth cells, α-defensins, termed cryptdins (Crps), are activated by matrix metalloproteinase-7-mediated proteolysis of inactive precursors (pro-Crps) to bactericidal forms. The activating cleavage step at Ser43 ↓ Ile44 in mouse pro-Crp4-(20–92) removes nine acidic amino acids that collectively block the membrane-disruptive behavior of the Crp4 moiety of the proform. This inhibitory mechanism has been investigated further to identify whether specific cluster(s) of electronegative amino acids in pro-Crp4-(20–43) are responsible for blocking bactericidal activity and membrane disruption. To test whether specific cluster(s) of electronegative amino acids in pro-Crp4-(20–43) have specific positional effects that block bactericidal peptide activity and membrane disruption, acidic residues positioned at the distal (Asp20, Asp26, Glu27, and Glu28), mid (Glu32 and Glu33), and proximal (Glu37, Glu38, and Asp39) clusters in pro-Crp4-(20–92) were mutagenized, and variants were assayed for differential effects of mutagenesis on bactericidal peptide activity. Substitution of the mid and proximal Asp and Glu clusters with Gly produced additive effects with respect to the induction of both bactericidal activity and membrane permeabilization of live Escherichia coli ML35 cells. In contrast, substitution of distal Glu and Asp residues with Gly or their deletion resulted in pro-Crp4-(20–92) variants with bactericidal and membrane-disruptive activities equal to or greater than that of fully mature Crp4. These findings support the conclusion that the most distal N-terminal anionic residues of pro-Crp4-(20–92) are primarily responsible for blocking Crp4-mediated membrane disruption in the precursor. PMID:19106102

  3. Macrophage Bactericidal Activities against Staphylococcus aureus Are Enhanced In Vivo by Selenium Supplementation in a Dose-Dependent Manner

    PubMed Central

    Aribi, Mourad; Meziane, Warda; Habi, Salim; Boulatika, Yasser

    2015-01-01

    Background Dietary selenium is of fundamental importance to maintain optimal immune function and enhance immunity during infection. To this end, we examined the effect of selenium on macrophage bactericidal activities against Staphylococcus aureus. Methods Assays were performed in golden Syrian hamsters and peritoneal macrophages cultured with S. aureus and different concentrations of selenium. Results Infected and selenium-supplemented animals have significantly decreased levels of serum nitric oxide (NO) production when compared with infected but non-selenium-supplemented animals at day 7 post-infection (p < 0.05). A low dose of 5 ng/mL selenium induced a significant decrease in macrophage NO production, but significant increase in hydrogen peroxide (H2O2) levels (respectively, p = 0.009, p < 0.001). The NO production and H2O2 levels were significantly increased with increasing concentrations of selenium; the optimal macrophage activity levels were reached at 20 ng/mL. The concentration of 5 ng/mL of selenium induced a significant decrease in the bacterial arginase activity but a significant increase in the macrophage arginase activity. The dose of 20 ng/mL selenium induced a significant decrease of bacterial growth (p < 0.0001) and a significant increase in macrophage phagocytic activity, NO production/arginase balance and S. aureus killing (for all comparisons, p < 0.001). Conclusions Selenium acts in a dose-dependent manner on macrophage activation, phagocytosis and bacterial killing suggesting that inadequate doses may cause a loss of macrophage bactericidal activities and that selenium supplementation could enhance the in vivo control of immune response to S. aureus. PMID:26340099

  4. Antimicrobial Activity of Peptides Derived from Olive Flounder Lipopolysaccharide Binding Protein/Bactericidal Permeability-Increasing Protein (LBP/BPI)

    PubMed Central

    Nam, Bo-Hye; Moon, Ji-Young; Park, Eun-Hee; Kim, Young-Ok; Kim, Dong-Gyun; Kong, Hee Jeong; Kim, Woo-Jin; Jee, Young Ju; An, Cheul Min; Park, Nam Gyu; Seo, Jung-Kil

    2014-01-01

    We describe the antimicrobial function of peptides derived from the C-terminus of the olive flounder LBP BPI precursor protein. The investigated peptides, namely, ofLBP1N, ofLBP2A, ofLBP4N, ofLBP5A, and ofLBP6A, formed α-helical structures, showing significant antimicrobial activity against several Gram-negative bacteria, Gram-positive bacteria, and the yeast Candida albicans, but very limited hemolytic activities. The biological activities of these five analogs were evaluated against biomembranes or artificial membranes for the development of candidate therapeutic agents. Gel retardation studies revealed that peptides bound to DNA and inhibited migration on an agarose gel. In addition, we demonstrated that ofLBP6A inhibited polymerase chain reaction. These results suggested that the ofLBP-derived peptide bactericidal mechanism may be related to the interaction with intracellular components such as DNA or polymerase. PMID:25329706

  5. Mycobacterial Protein Tyrosine Phosphatases A and B Inhibitors Augment the Bactericidal Activity of the Standard Anti-tuberculosis Regimen

    PubMed Central

    Dutta, Noton K.; He, Rongjun; Pinn, Michael L.; He, Yantao; Burrows, Francis; Zhang, Zhong-Yin; Karakousis, Petros C.

    2016-01-01

    Novel drugs are required to shorten the duration of treatment for tuberculosis (TB) and to combat the emergence of drug resistance. One approach has been to identify and target Mycobacterium tuberculosis (Mtb) virulence factors, which promote the establishment of TB infection and pathogenesis. Mtb produces a number of virulence factors, including two protein tyrosine phosphatases (PTPs), mPTPA and mPTPB, to evade the antimicrobial functions of host macrophages. To assess the therapeutic potential of targeting the virulent Mtb PTPs, we developed highly potent and selective inhibitors of mPTPA (L335-M34) and mPTPB (L01-Z08) with drug-like properties. We tested the bactericidal activity of L335-M34 and L01-Z08 alone or together in combination with the standard antitubercular regimen of isoniazid-rifampicin-pyrazinamide (HRZ) in the guinea pig model of chronic TB infection, which faithfully recapitulates some of the key histological features of human TB lesions. Following a single dose of L335-M34 50mg/kg and L01-Z08 20 mg/kg, plasma levels were maintained at levels 10-fold greater than the biochemical IC50 for 12–24 hours. Although neither PTP inhibitor alone significantly enhanced the antibacterial activity of HRZ, dual inhibition of mPTPA and mPTPB in combination with HRZ showed modest synergy, even after 2 weeks of treatment. After 6 weeks of treatment, the degree of lung inflammation correlated with the bactericidal activity of each drug regimen. This study highlights the potential utility of targeting Mtb virulence factors, and specifically the Mtb PTPs, as a strategy for enhancing the activity of standard anti-TB treatment. PMID:27478867

  6. Aging Enhances the Production of Reactive Oxygen Species and Bactericidal Activity in Peritoneal Macrophages by Upregulating Classical Activation Pathways

    SciTech Connect

    Smallwood, Heather S.; López-Ferrer, Daniel; Squier, Thomas C.

    2011-10-07

    Maintenance of macrophages in their basal state and their rapid activation in response to pathogen detection are central to the innate immune system, acting to limit nonspecific oxidative damage and promote pathogen killing following infection. To identify possible age-related alterations in macrophage function, we have assayed the function of peritoneal macrophages from young (3–4 months) and aged (14–15 months) Balb/c mice. In agreement with prior suggestions, we observe age-dependent increases in the extent of recruitment of macrophages into the peritoneum, as well as ex vivo functional changes involving enhanced nitric oxide production under resting conditions that contribute to a reduction in the time needed for full activation of senescent macrophages following exposure to lipopolysaccharides (LPS). Further, we observe enhanced bactericidal activity following Salmonella uptake by macrophages isolated from aged Balb/c mice in comparison with those isolated from young animals. Pathways responsible for observed phenotypic changes were interrogated using tandem mass spectrometry, which identified age-dependent increases in levels of proteins linked to immune cell pathways under basal conditions and following LPS activation. Immune pathways upregulated in macrophages isolated from aged mice include proteins critical to the formation of the immunoproteasome. Detection of these latter proteins is dramatically enhanced following LPS exposure for macrophages isolated from aged animals; in comparison, the identification of immunoproteasome subunits is insensitive to LPS exposure for macrophages isolated from young animals. Consistent with observed global changes in the proteome, quantitative proteomic measurements indicate that there are age-dependent abundance changes involving specific proteins linked to immune cell function under basal conditions. LPS exposure selectively increases the levels of many proteins involved in immune cell function in aged Balb/c mice

  7. Aging enhances the production of reactive oxygen species and bactericidal activity in peritoneal macrophages by upregulating classical activation pathways.

    PubMed

    Smallwood, Heather S; López-Ferrer, Daniel; Squier, Thomas C

    2011-11-15

    Maintenance of macrophages in their basal state and their rapid activation in response to pathogen detection are central to the innate immune system, acting to limit nonspecific oxidative damage and promote pathogen killing following infection. To identify possible age-related alterations in macrophage function, we have assayed the function of peritoneal macrophages from young (3-4 months) and aged (14-15 months) Balb/c mice. In agreement with prior suggestions, we observe age-dependent increases in the extent of recruitment of macrophages into the peritoneum, as well as ex vivo functional changes involving enhanced nitric oxide production under resting conditions that contribute to a reduction in the time needed for full activation of senescent macrophages following exposure to lipopolysaccharides (LPS). Further, we observe enhanced bactericidal activity following Salmonella uptake by macrophages isolated from aged Balb/c mice in comparison with those isolated from young animals. Pathways responsible for observed phenotypic changes were interrogated using tandem mass spectrometry, which identified age-dependent increases in levels of proteins linked to immune cell pathways under basal conditions and following LPS activation. Immune pathways upregulated in macrophages isolated from aged mice include proteins critical to the formation of the immunoproteasome. Detection of these latter proteins is dramatically enhanced following LPS exposure for macrophages isolated from aged animals; in comparison, the identification of immunoproteasome subunits is insensitive to LPS exposure for macrophages isolated from young animals. Consistent with observed global changes in the proteome, quantitative proteomic measurements indicate that there are age-dependent abundance changes involving specific proteins linked to immune cell function under basal conditions. LPS exposure selectively increases the levels of many proteins involved in immune cell function in aged Balb/c mice

  8. Immunity to Escherichia coli in pigs: Serum Gamma Globulin Levels, Indirect Hemagglutinating Antibody Titres and Bactericidal Activity Against E. coli in pigs up to five Weeks of Age

    PubMed Central

    Wilson, M. R.; Svendsen, J.

    1972-01-01

    Serum gamma globulin levels, indirect hemagglutinating antibody titres and bactericidal activity against the 0149:K91;K88ac:H10 Serotype of Escherichia coli were determined in pigs up to five weeks of age from vaccinated and non-vaccinated sows. Gamma globulin levels at two days of age were approximately twice adult levels, by three weeks of age they were one quarter of adult levels and remained so until five weeks of age. Indirect hemagglutinating antibody activity was highest at two days of age, fell until three weeks of age and then rose. Little or no indirect hemagglutinating antibody activity was detected in sera taken at two days of age from pigs from non-vaccinated sows. Only three of 26 two day old pigs had demonstrable bactericidal activity; by three weeks of age 16 of 26 had bactericidal activity. Serum from piglets of vaccinated sows had no more bactericidal activity than did sera from non-vaccinated sows. PMID:4110608

  9. Reverse inoculum effect in bactericidal activity and other variables affecting killing of group B streptococci by penicillin.

    PubMed Central

    Jokipii, L; Brander, P; Jokipii, A M

    1985-01-01

    Variables of the effect of penicillin G on the numbers of viable group B streptococci in broth cultures were studied. One-fourth of the MIC was the lowest concentration that reduced the viable count compared with antibiotic-free controls. The rate of killing increased with the concentration of penicillin up to 4 X MIC, but no further. During the first 2 or 3 h, the bactericidal activity was more rapid than later on. The MIC and supraoptimal concentrations of penicillin killed an inoculum of 10(6) organisms more rapidly than an inoculum of 10(4) organisms. The MIC was not inoculum dependent. The reverse inoculum effect was revealed by the killing curves but not by the MBC. There were reproducible differences among strains as to the rate of killing by penicillin; these did not correlate with the rate of multiplication, which also varied among strains. Among the 11 strains tested, there were no tolerant ones. PMID:3896137

  10. Bacteriostatic and bactericidal activities of benzoxazinorifamycin KRM-1648 against Mycobacterium tuberculosis and Mycobacterium avium in human macrophages.

    PubMed Central

    Mor, N; Simon, B; Heifets, L

    1996-01-01

    Inhibitory and bactericidal activities of KRM-1648 were determined against Mycobacterium tuberculosis and M. avium residing in human monocyte-derived macrophages and extracellular M. tuberculosis and M. avium. MICs and MBCs of KRM-1648 against intracellular and extracellular bacteria were substantially lower than those of rifampin. The MICs and MBCs of either drug against the intracellular bacteria were only twofold lower than or equal to the values found for extracellular bacteria. The prolonged effect of KRM-1648 found in this study is probably associated with high ratios of intracellular accumulation, which were 50- to 100-fold higher than that found for rifampin. Further studies on intracellular distribution of KRM-1648 and on the sites of actual interaction between the drug and bacteria residing in macrophages are necessary, as well as evaluation of combined effects of KRM-1648 with other drugs in long-term macrophage culture experiments. PMID:8726023

  11. Correlation between bactericidal activity of fosfomycin trometamol in an in vitro model of the urinary bladder and susceptibility testing.

    PubMed

    Pinasi, C; Albini, E; Marca, G

    1987-01-01

    The present study was undertaken to define an interpretative guideline for disk diffusion susceptibility testing with fosfomycin trometamol, a new antimicrobial agent which has been developed for the treatment of urinary tract infections. Two potencies of fosfomycin disk were used: 50 and 200 micrograms, prepared in the presence and absence of glucose-6-phosphate. To verify the reliability of the results obtained in susceptibility testing, we have also evaluated the bactericidal activity of fosfomycin trometamol versus sensitive and resistant strains in an 'in vitro' model simulating the hydrokinetic aspects involved in the treatment of bacterial cystitis. The data obtained evidenced the role of glucose-6-phosphate in antimicrobial susceptibility tests as well as the importance of the urinary antibiotic concentrations to define sensitive and resistant bacteria. On the basis of our results, we recommend that a 200-microgram disk of fosfomycin containing 50 micrograms of glucose-6-phosphate should be used in antimicrobial susceptibility testing with fosfomycin trometamol.

  12. Enhanced Photothermal Bactericidal Activity of the Reduced Graphene Oxide Modified by Cationic Water-Soluble Conjugated Polymer.

    PubMed

    Xiao, Linhong; Sun, Jinhua; Liu, Libing; Hu, Rong; Lu, Huan; Cheng, Chungui; Huang, Yong; Wang, Shu; Geng, Jianxin

    2017-02-15

    Surface modification of graphene is extremely important for applications. Here, we report a grafting-through method for grafting water-soluble polythiophenes onto reduced graphene oxide (RGO) sheets. As a result of tailoring of the side chains of the polythiophenes, the modified RGO sheets, that is, RGO-g-P3TOPA and RGO-g-P3TOPS, are positively and negatively charged, respectively. The grafted water-soluble polythiophenes provide the modified RGO sheets with good dispersibility in water and high photothermal conversion efficiencies (ca. 88%). Notably, the positively charged RGO-g-P3TOPA exhibits unprecedentedly excellent photothermal bactericidal activity, because the electrostatic attractions between RGO-g-P3TOPA and Escherichia coli (E. coli) bind them together, facilitating direct heat conduction through their interfaces: the minimum concentration of RGO-g-P3TOPA that kills 100% of E. coli is 2.5 μg mL(-1), which is only 1/16th of that required for RGO-g-P3TOPS to exhibit a similar bactericidal activity. The direct heat conduction mechanism is supported by zeta-potential measurements and photothermal heating tests, in which the achieved temperature of the RGO-g-P3TOPA suspension (2.5 μg mL(-1), 32 °C) that kills 100% of E. coli is found to be much lower than the thermoablation threshold of bacteria. Therefore, this research demonstrates a novel and superior method that combines photothermal heating effect and electrostatic attractions to efficiently kill bacteria.

  13. Bactericidal activity of green tea extracts: the importance of catechin containing nano particles.

    PubMed

    Gopal, Judy; Muthu, Manikandan; Paul, Diby; Kim, Doo-Hwan; Chun, Sechul

    2016-01-28

    When we drink green tea infusion, we believe we are drinking the extract of the green tea leaves. While practically each tea bag infused in 300 mL water contains about 50 mg of suspended green tea leaf particles. What is the role of these particles in the green tea effect is the objective of this study. These particles (three different size ranges) were isolated via varying speed centrifugation and their respective inputs evaluated. Live oral bacterial samples from human volunteers have been screened against green tea extracts and macro, micro and nano sized green tea particles. The results showed that the presence/absence of the macro and mico sized tea particles in the green tea extract did not contribute much. However, the nano sized particles were characterized to be nature's nano stores of the bioactive catechins. Eradication of these nano tea particles resulted in decrease in the bactericidal property of the green tea extracts. This is a curtain raiser investigation, busting the nano as well as green tea leaf particle contribution in green tea extracts.

  14. Comparison of bactericidal activity of six lysozymes at atmospheric pressure and under high hydrostatic pressure.

    PubMed

    Nakimbugwe, Dorothy; Masschalck, Barbara; Atanassova, Miroslava; Zewdie-Bosüner, Abebetch; Michiels, Chris W

    2006-05-01

    The antibacterial working range of six lysozymes was tested under ambient and high pressure, on a panel of five gram-positive (Enterococcus faecalis, Bacillus subtilis, Listeria innocua, Staphylococcus aureus and Micrococcus lysodeikticus) and five gram-negative bacteria (Yersinia enterocolitica, Shigella flexneri, Escherichia coli O157:H7, Pseudomonas aeruginosa and Salmonella typhimurium). The lysozymes included two that are commercially available (hen egg white lysozyme or HEWL, and mutanolysin from Streptomyces globisporus or M1L), and four that were chromatographically purified (bacteriophage lambda lysozyme or LaL, bacteriophage T4 lysozyme or T4L, goose egg white lysozyme or GEWL, and cauliflower lysozyme or CFL). T4L, LaL and GEWL were highly pure as evaluated by silver staining of SDS-PAGE gels and zymogram analysis while CFL was only partially pure. At ambient pressure each gram-positive test organism displayed a specific pattern of sensitivity to the six lysozymes, but none of the gram-negative bacteria was sensitive to any of the lysozymes. High pressure treatment (130-300 MPa, 25 degrees C, 15 min) sensitised several gram-positive and gram-negative bacteria for one or more lysozymes. M. lysodeikticus and P. aeruginosa became sensitive to all lysozymes under high pressure, S. typhimurium remained completely insensitive to all lysozymes, and the other bacteria showed sensitisation to some of the lysozymes. The possible applications of the different lysozymes as biopreservatives, and the possible reasons for the observed differences in bactericidal specificity are discussed.

  15. Bactericidal activity of green tea extracts: the importance of catechin containing nano particles

    PubMed Central

    Gopal, Judy; Muthu, Manikandan; Paul, Diby; Kim, Doo-Hwan; Chun, Sechul

    2016-01-01

    When we drink green tea infusion, we believe we are drinking the extract of the green tea leaves. While practically each tea bag infused in 300 mL water contains about 50 mg of suspended green tea leaf particles. What is the role of these particles in the green tea effect is the objective of this study. These particles (three different size ranges) were isolated via varying speed centrifugation and their respective inputs evaluated. Live oral bacterial samples from human volunteers have been screened against green tea extracts and macro, micro and nano sized green tea particles. The results showed that the presence/absence of the macro and mico sized tea particles in the green tea extract did not contribute much. However, the nano sized particles were characterized to be nature’s nano stores of the bioactive catechins. Eradication of these nano tea particles resulted in decrease in the bactericidal property of the green tea extracts. This is a curtain raiser investigation, busting the nano as well as green tea leaf particle contribution in green tea extracts. PMID:26818408

  16. Ability of Staphylococcus aureus coagulase genotypes to resist neutrophil bactericidal activity and phagocytosis.

    PubMed Central

    Aarestrup, F M; Scott, N L; Sordillo, L M

    1994-01-01

    This study investigated the functional capabilities of neutrophils against different Staphylococcus aureus genotypes isolated from cows with mastitis. Six strains of S. aureus were chosen for use in the study, two with a common genotype, two with an intermediate genotype, and two with a rare genotype. The interaction between bacteria and neutrophils was measured by phagocytosis and bactericidal effect. The average percent killing of bacteria was lowest (40.0%) with strains belonging to the most common genotype, medium (50%) with strains belonging to the intermediate type, and highest (64.2%) with strains belonging to the rare type (P < or = 0.001). Statistically significant differences (P < or = 0.001) in the numbers of phagocytized bacteria were also found between the most prevalent type (6.27 bacteria per cell) and the other two types (intermediate type, 9.26/cell; rare type, 10.5/cell). These findings suggest that one of the reasons for the variation in prevalence of different genotypes of S. aureus in the mammary gland is due to the superior ability of some types to resist phagocytosis and/or killing by bovine neutrophils. PMID:7960153

  17. Validity of the four European test strains of prEN 12054 for the determination of comprehensive bactericidal activity of an alcohol-based hand rub.

    PubMed

    Kampf, G; Hollingsworth, A

    2003-11-01

    A comprehensive bactericidal activity of an alcohol-based hand rub is essential for prevention of cross-transmission by the hands of healthcare workers. In Europe, however, only four test organisms are used to determine bactericidal activity according to prEN 12054. The susceptibility of the various bacterial species against the commonly used alcohols is thought to be similar, but so far this has never been studied. We therefore evaluated the bactericidal activity of an alcohol-based hand rub (Sterillium) within 30 s in compliance with prEN 12054 and in a time kill test against 13 Gram-positive, 18 Gram-negative bacteria and 14 antibiotic-resistant bacterial pathogens. Each strain was evaluated in quadruplicate. Counts of the four test bacteria of prEN 12054 were reduced by factors exceeding 10(5) within 30 s. In the time kill test, all 13 Gram-positive and all 18 Gram-negative bacteria were reduced more than 10(5)-fold within 30 s, not only against the ATCC test strains but also against corresponding clinical isolates. Comparable reductions were also observed against all 14 emerging bacterial pathogens. The four European test bacteria were found to be sufficient to determine a comprehensive bactericidal activity of a propanol-based hand rub.

  18. Bactericidal activities of health-promoting,food-derived powders against the foodborne pathogens Escherichia coli,listeria monocytogenes, salmonella enterica,and staphylococcus aureus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We evaluated the relative bactericidal activities of 10 presumed health-promoting food-based powders (nutraceuticals) and for comparison, several selected known components of such powders against the following foodborne pathogens: Escherichia coli O157:H7, Salmonella enterica, Listeria monocytogenes...

  19. Antimicrobial activity of human α-defensin 6 analogs: insights into the physico-chemical reasons behind weak bactericidal activity of HD6 in vitro.

    PubMed

    Mathew, Basil; Nagaraj, Ramakrishnan

    2015-11-01

    Human α-defensin 6 (HD6), unlike other mammalian defensins, does not exhibit bactericidal activity, particularly against aerobic bacteria. Monomeric HD6 has a tertiary structure similar to other α-defensins in the crystalline state. However, the physico-chemical reasons behind the lack of antibacterial activity of HD6 are yet to be established unequivocally. In this study, we have investigated the antimicrobial activity of HD6 analogs. A linear analog of HD6, in which the distribution of arginine residues was similar to active α-defensins, shows broad-spectrum antimicrobial activity, indicating that atypical distribution of arginine residues contributes to the inactivity of HD6. Peptides spanning the N-terminal cationic segment were active against a wide range of organisms. Antimicrobial potency of these shorter analogs was further enhanced when myristic acid was conjugated at the N-terminus. Cytoplasmic localization of the analogs without fatty acylation was observed to be necessary for bacterial killing, while they exhibited fungicidal activity by permeabilizing Candida albicans membranes. Myristoylated analogs and the linear full-length arginine analog exhibited activity by permeabilizing bacterial and fungal membranes. Our study provides insights into the lack of bactericidal activity of HD6 against aerobic bacteria.

  20. Synergistic interaction between wavelength of light and concentration of H₂O₂ in bactericidal activity of photolysis of H₂O₂.

    PubMed

    Toki, Toshihide; Nakamura, Keisuke; Kurauchi, Michiko; Kanno, Taro; Katsuda, Yusuke; Ikai, Hiroyo; Hayashi, Eisei; Egusa, Hiroshi; Sasaki, Keiichi; Niwano, Yoshimi

    2015-03-01

    The present study aimed to evaluate the interaction between wavelength of light in the range of ultra violet A-visible and concentration of H2O2 in the reaction of photolysis of H2O2 from the point of view of hydroxyl radical (·OH) generation and the bactericidal activity. Light emitting diodes (LEDs) emitting the light at wavelengths of 365, 385, 400 and 465 nm were used at an irradiance of 1000 mW/cm(2). H2O2 was used at the final concentrations of 0, 250, 500, and 1000 mM. Quantitative analysis of ·OH generated by the LED irradiation of H2O2 were performed using an electron spin resonance-spin trapping technique. In a bactericidal assay, a bacterial suspension of Staphylococcus aureus prepared in sterile physiological saline was irradiated with the LEDs. The bactericidal activity of each test condition was evaluated by viable counts. When H2O2 was irradiated with the LEDs, ·OH was generated and bacteria were killed dependently on the concentration of H2O2 and the wavelength of LED. The two-way analysis of variance revealed that the wavelength, the H2O2 concentration and their interaction significantly affected the yield of ·OH and the bactericidal activity of the photolysis of H2O2. Therefore, it is suggested that bactericidal activity of photolysis of H2O2 could be enhanced by controlling the wavelength and the concentration of H2O2, which may contributes to shortening the treatment time and/or to reducing the concentration of H2O2.

  1. Nanostructured poly (lactic acid) electrospun fiber with high loadings of TiO2 nanoparticles: Insights into bactericidal activity and cell viability.

    PubMed

    Toniatto, T V; Rodrigues, B V M; Marsi, T C O; Ricci, R; Marciano, F R; Webster, T J; Lobo, A O

    2017-02-01

    Researchers have been looking for modifying surfaces of polymeric biomaterials approved by FDA to obtain nanofeatures and bactericidal properties. If modified, it would be very interesting because the antibiotic administration could be reduced and, therefore, the bacterial resistance. Here, we report the electrospinning of poly (lactic acid) (PLA) with high loadings of titanium dioxide nanoparticles (TiO2, 1-5wt%) and their bactericidal properties. TiO2 nanoparticles have been recognized for a long time for their antibacterial, low cost and self-cleaning properties. However, their ability to reduce bacteria functions when used in polymers has not been well studied to date. In this context, we aimed here to generate nanostructured PLA electrospun fiber-TiO2 nanoparticle composites for further evaluation of their bactericidal activity and cell viability. TEM and SEM micrographs revealed the successful electrospinning of PLA/TiO2 and the generation of polymer-TiO2 nanostructures. When increasing the TiO2 concentration, we observed a proportional increase in the nanoparticle density along the fiber and surface. The nanostructured PLA/TiO2 nanofibers showed no mammalian cell toxicity and, most importantly, possessed bactericidal activity with higher TiO2 loads. Such results suggest that the present PLA electrospun fiber-TiO2 nanoparticle composites should be further studied for a wide range of biomedical applications.

  2. Bactericidal activity and mechanism of action of copper-sputtered flexible surfaces against multidrug-resistant pathogens.

    PubMed

    Ballo, Myriam K S; Rtimi, Sami; Mancini, Stefano; Kiwi, John; Pulgarin, César; Entenza, José M; Bizzini, Alain

    2016-07-01

    Using direct current magnetron sputtering (DCMS), we generated flexible copper polyester surfaces (Cu-PES) and investigated their antimicrobial activity against a range of multidrug-resistant (MDR) pathogens including eight Gram-positive isolates (three methicillin-resistant Staphylococcus aureus [MRSA], four vancomycin-resistant enterococci, one methicillin-resistant Staphylococcus epidermidis) and four Gram-negative strains (one extended-spectrum β-lactamase-producing [ESBL] Escherichia coli, one ESBL Klebsiella pneumoniae, one imipenem-resistant Pseudomonas aeruginosa, and one ciprofloxacin-resistant Acinetobacter baumannii). Bactericidal activity (≥3 log10 CFU reduction of the starting inoculum) was reached within 15-30 min exposure to Cu-PES. Antimicrobial activity of Cu-PES persisted in the absence of oxygen and against both Gram-positive and Gram-negative bacteria containing elevated levels of catalases, indicating that reactive oxygen species (ROS) do not play a primary role in the killing process. The decrease in cell viability of MRSA ATCC 43300 and Enterococcus faecalis V583 correlated with the progressive loss of cytoplasmic membrane integrity both under aerobic and anaerobic conditions, suggesting that Cu-PES mediated killing is primarily induced by disruption of the cytoplasmic membrane function. Overall, we here present novel antimicrobial copper surfaces with improved stability and sustainability and provide further insights into their mechanism of killing.

  3. Comparative study of bactericidal activities, postantibiotic effects, and effects of bacterial virulence of penicillin G and six macrolides against Streptococcus pneumoniae.

    PubMed

    Fuursted, K; Knudsen, J D; Petersen, M B; Poulsen, R L; Rehm, D

    1997-04-01

    In this report, we present MIC, bactericidal activity, postantibiotic effect (PAE), and in vivo infectivity data for postantibiotic-phase pneumococci. We compared and evaluated penicillin G and six macrolides, erythromycin, azithromycin, clarithromycin, dirithromycin, roxithromycin, and spiramycin, against 10 strains of pneumococci with various levels of susceptibility to penicillin. All of the agents, except azithromycin, exhibited a bactericidal effect (a > or = 3 log10 decrease in the number of CFU per milliliter) after 4 h of exposure to a concentration equal to 10 times the MIC, displaying the following hierarchy: spiramycin = penicillin G = erythromycin = dirithromycin = clarithromycin = roxithromycin > azithromycin. The bactericidal rate of penicillin G was significantly lower for resistant strains (MIC, > or = 2 microg/ml), while bactericidal rates of macrolides were unaffected by penicillin susceptibility. A PAE was induced in all of the strains by all of the antibiotics after exposure for 1 h to a concentration equivalent to 10 times the MIC. The mean duration of PAEs varied between 2.3 and 3.9 h, showing the following hierarchy: spiramycin = dirithromycin = clarithromycin = erythromycin = roxithromycin > azithromycin > penicillin G. Virulence studies were performed with immunocompetent mice by intraperitoneal inoculation of virulent, penicillin-susceptible serotype 3 pneumococci which had been pre-exposed to penicillin G or a macrolide for 1 h. A significant decrease in the virulence of postantibiotic-phase pneumococci was induced only by erythromycin, azithromycin, dirithromycin, and spiramycin, displaying 5.9-, 7.1-, 4.2-, and 3.6-fold increases in the 50% lethal dose (LD50) compared to a control suspension, respectively. No significant correlation could be demonstrated between the LD50 and the MIC, bactericidal activity, or PAE duration. These results suggest that antimicrobial interaction with host defenses in terms of virulence might be a

  4. Direct Comparison of Xpert MTB/RIF Assay with Liquid and Solid Mycobacterial Culture for Quantification of Early Bactericidal Activity

    PubMed Central

    Kayigire, Xavier A.; Friedrich, Sven O.; Venter, Amour; Dawson, Rodney; Gillespie, Stephen H.; Boeree, Martin J.; Heinrich, Norbert; Hoelscher, Michael

    2013-01-01

    The early bactericidal activity of antituberculosis agents is usually determined by measuring the reduction of the sputum mycobacterial load over time on solid agar medium or in liquid culture. This study investigated the value of a quantitative PCR assay for early bactericidal activity determination. Groups of 15 patients were treated with 6 different antituberculosis agents or regimens. Patients collected sputum for 16 h overnight at baseline and at days 7 and 14 after treatment initiation. We determined the sputum bacterial load by CFU counting (log CFU/ml sputum, reported as mean ± standard deviation [SD]), time to culture positivity (TTP, in hours [mean ± SD]) in liquid culture, and Xpert MTB/RIF cycle thresholds (CT, n [mean ± SD]). The ability to discriminate treatment effects between groups was analyzed with one-way analysis of variance (ANOVA). All measurements showed a decrease in bacterial load from mean baseline (log CFU, 5.72 ± 1.00; TTP, 116.0 ± 47.6; CT, 19.3 ± 3.88) to day 7 (log CFU, −0.26 ± 1.23, P = 0.2112; TTP, 35.5 ± 59.3, P = 0.0002; CT, 0.55 ± 3.07, P = 0.6030) and day 14 (log CFU, −0.55 ± 1.24, P = 0.0006; TTP, 54.8 ± 86.8, P < 0.0001; CT, 2.06 ± 4.37, P = 0.0020). The best discrimination between group effects was found with TTP at day 7 and day 14 (F = 9.012, P < 0.0001, and F = 11.580, P < 0.0001), followed by log CFU (F = 4.135, P = 0.0024, and F = 7.277, P < 0.0001). CT was not significantly discriminative (F = 1.995, P = 0.091, and F = 1.203, P = 0.316, respectively). Culture-based methods are superior to PCR for the quantification of early antituberculosis treatment effects in sputum. PMID:23596237

  5. Direct comparison of Xpert MTB/RIF assay with liquid and solid mycobacterial culture for quantification of early bactericidal activity.

    PubMed

    Kayigire, Xavier A; Friedrich, Sven O; Venter, Amour; Dawson, Rodney; Gillespie, Stephen H; Boeree, Martin J; Heinrich, Norbert; Hoelscher, Michael; Diacon, Andreas H

    2013-06-01

    The early bactericidal activity of antituberculosis agents is usually determined by measuring the reduction of the sputum mycobacterial load over time on solid agar medium or in liquid culture. This study investigated the value of a quantitative PCR assay for early bactericidal activity determination. Groups of 15 patients were treated with 6 different antituberculosis agents or regimens. Patients collected sputum for 16 h overnight at baseline and at days 7 and 14 after treatment initiation. We determined the sputum bacterial load by CFU counting (log CFU/ml sputum, reported as mean ± standard deviation [SD]), time to culture positivity (TTP, in hours [mean ± SD]) in liquid culture, and Xpert MTB/RIF cycle thresholds (C(T), n [mean ± SD]). The ability to discriminate treatment effects between groups was analyzed with one-way analysis of variance (ANOVA). All measurements showed a decrease in bacterial load from mean baseline (log CFU, 5.72 ± 1.00; TTP, 116.0 ± 47.6; C(T), 19.3 ± 3.88) to day 7 (log CFU, -0.26 ± 1.23, P = 0.2112; TTP, 35.5 ± 59.3, P = 0.0002; C(T), 0.55 ± 3.07, P = 0.6030) and day 14 (log CFU, -0.55 ± 1.24, P = 0.0006; TTP, 54.8 ± 86.8, P < 0.0001; C(T), 2.06 ± 4.37, P = 0.0020). The best discrimination between group effects was found with TTP at day 7 and day 14 (F = 9.012, P < 0.0001, and F = 11.580, P < 0.0001), followed by log CFU (F = 4.135, P = 0.0024, and F = 7.277, P < 0.0001). C(T) was not significantly discriminative (F = 1.995, P = 0.091, and F = 1.203, P = 0.316, respectively). Culture-based methods are superior to PCR for the quantification of early antituberculosis treatment effects in sputum.

  6. Bactericidal activity identified in 2S Albumin from sesame seeds and in silico studies of structure-function relations.

    PubMed

    Maria-Neto, Simone; Honorato, Rodrigo V; Costa, Fábio T; Almeida, Renato G; Amaro, Daniel S; Oliveira, José T A; Vasconcelos, Ilka M; Franco, Octávio L

    2011-06-01

    Pathogenic bacteria constitute an important cause of hospital-acquired infections. However, the misuse of available bactericidal agents has led to the appearance of antibiotic-resistant strains. Thus, efforts to seek new antimicrobials with different action mechanisms would have an enormous impact. Here, a novel antimicrobial protein (SiAMP2) belonging to the 2S albumin family was isolated from Sesamum indicum kernels and evaluated against several bacteria and fungi. Furthermore, in silico analysis was conducted in order to identify conserved residues through other 2S albumin antimicrobial proteins (2S-AMPs). SiAMP2 specifically inhibited Klebsiella sp. Specific regions in the molecule surface where cationic (RR/RRRK) and hydrophobic (MEYWPR) residues are exposed and conserved were proposed as being involved in antimicrobial activity. This study reinforces the hypothesis that plant storage proteins might also play as pathogen protection providing an insight into the mechanism of action for this novel 2S-AMP and evolutionary relations between antimicrobial activity and 2S albumins.

  7. Bactericidal Activity of Methanol Extracts of Crabapple Mangrove Tree (Sonneratia caseolaris Linn.) Against Multi-Drug Resistant Pathogens

    PubMed Central

    Yompakdee, C.; Thunyaharn, S.; Phaechamud, T.

    2012-01-01

    The crabapple mangrove tree, Sonneratia caseolaris Linn. (Family: Sonneratiaceae), is one of the foreshore plants found in estuarine and tidal creek areas and mangrove forests. Bark and fruit extracts from this plant have previously been shown to have an anti-oxidative or cytotoxic effect, whereas flower extracts of this plant exhibited an antimicrobial activity against some bacteria. According to the traditional folklore, it is medicinally used as an astringent and antiseptic. Hence, this investigation was carried out on the extract of the leaves, pneumatophore and different parts of the flower or fruit (stamen, calyx, meat of fruit, persistent calyx of fruit and seeds) for antibacterial activity using the broth microdilution method. The antibacterial activity was evaluated against five antibiotic-sensitive species (three Gram-positive and two Gram-negative bacteria) and six drug-resistant species (Gram-positive i.e. Methicillin-resistant Staphylococcus aureus, Enterococcus faecalis, Enterococcus faecium and Gram-negative i.e. Extended-spectrum beta-lactamase-Escherichia coli, multidrug-resistant–Pseudomonas aeruginosa and Acenetobacter baumannii). The methanol extracts from all tested parts of the crabapple mangrove tree exhibited antibacterial activity against both Gram-positive and Gram-negative bacteria, but was mainly a bactericidal against the Gram-negative bacteria, including the multidrug-resistant strains, when compared with only bacteriostatic on the Gram-positive bacteria. Using Soxhlet apparatus, the extracts obtained by sequential extraction with hexane, dichloromethane and ethyl acetate revealed no discernable antibacterial activity and only slightly, if at all, reduced the antibacterial activity of the subsequently obtained methanol extract. Therefore, the active antibacterial compounds of the crabapple mangrove tree should have a rather polar structure. PMID:23441048

  8. Bactericidal Activity of Methanol Extracts of Crabapple Mangrove Tree (Sonneratia caseolaris Linn.) Against Multi-Drug Resistant Pathogens.

    PubMed

    Yompakdee, C; Thunyaharn, S; Phaechamud, T

    2012-05-01

    The crabapple mangrove tree, Sonneratia caseolaris Linn. (Family: Sonneratiaceae), is one of the foreshore plants found in estuarine and tidal creek areas and mangrove forests. Bark and fruit extracts from this plant have previously been shown to have an anti-oxidative or cytotoxic effect, whereas flower extracts of this plant exhibited an antimicrobial activity against some bacteria. According to the traditional folklore, it is medicinally used as an astringent and antiseptic. Hence, this investigation was carried out on the extract of the leaves, pneumatophore and different parts of the flower or fruit (stamen, calyx, meat of fruit, persistent calyx of fruit and seeds) for antibacterial activity using the broth microdilution method. The antibacterial activity was evaluated against five antibiotic-sensitive species (three Gram-positive and two Gram-negative bacteria) and six drug-resistant species (Gram-positive i.e. Methicillin-resistant Staphylococcus aureus, Enterococcus faecalis, Enterococcus faecium and Gram-negative i.e. Extended-spectrum beta-lactamase-Escherichia coli, multidrug-resistant-Pseudomonas aeruginosa and Acenetobacter baumannii). The methanol extracts from all tested parts of the crabapple mangrove tree exhibited antibacterial activity against both Gram-positive and Gram-negative bacteria, but was mainly a bactericidal against the Gram-negative bacteria, including the multidrug-resistant strains, when compared with only bacteriostatic on the Gram-positive bacteria. Using Soxhlet apparatus, the extracts obtained by sequential extraction with hexane, dichloromethane and ethyl acetate revealed no discernable antibacterial activity and only slightly, if at all, reduced the antibacterial activity of the subsequently obtained methanol extract. Therefore, the active antibacterial compounds of the crabapple mangrove tree should have a rather polar structure.

  9. Inhibitory and bactericidal activities of levofloxacin, ofloxacin, erythromycin, and rifampin used singly and in combination against Legionella pneumophila.

    PubMed Central

    Baltch, A L; Smith, R P; Ritz, W

    1995-01-01

    The susceptibilities of 56 Legionella pneumophila isolates (43 clinical and 15 environmental isolates) to levofloxacin, ofloxacin, erythromycin, and rifampin were studied with buffered charcoal yeast extract (BCYE) agar (inoculum, 10(4) CFU per spot), and the susceptibilities of five isolates were studied with buffered yeast extract (BYE) broth (inoculum, 10(5) CFU/ml). The MICs inhibiting 90% of strains tested on BCYE agar were 0.125, 0.25, 1.0, and < or = 0.004 micrograms/ml for levofloxacin, ofloxacin, erythromycin, and rifampin, respectively. The MICs by the BYE broth dilution method were 1 to 3, 2, 1 to 2, and 1 tube lower than those by the agar dilution method for levofloxacin, ofloxacin, erythromycin, and rifampin, respectively. The MBCs were 1 to 2 tubes higher than the broth dilution MICs for levofloxacin, 1 to 3 tubes higher than the broth dilution MICs for ofloxacin, 1 to 3 tubes higher than the broth dilution MICs for erythromycin, and the same as the broth dilution MICs for rifampin. In kinetic time-kill curve studies, at drug concentrations of 1.0 and 2.0 times the MIC, the most active drugs were levofloxacin and rifampin. At 72 h, concentrations of levofloxacin and rifampin of 2.0 times the MIC demonstrated a bactericidal effect against L. pneumophila. In contrast, at concentrations of 1.0 and 2.0 times the MICs regrowth was observed with ofloxacin and only a gradual decrease in the numbers of CFU per milliliter was observed with erythromycin. Only a minor inhibitory effect was observed with 0.25 or 0.5 time the MICs of all drugs at 24 to 48 h, with regrowth occurring at 72 h. In contrast to erythromycin or ofloxacin plus rifampin at 0.25 time the MICs, only levofloxacin plus rifampin demonstrated synergy. Thus, levofloxacin demonstrated the best inhibitory and bactericidal effects against L. pneumophila when it was studied alone or in a combination with rifampin. PMID:7486896

  10. A Bayesian Nonlinear Mixed-Effects Regression Model for the Characterization of Early Bactericidal Activity of Tuberculosis Drugs

    PubMed Central

    Burger, Divan Aristo; Schall, Robert

    2015-01-01

    Trials of the early bactericidal activity (EBA) of tuberculosis (TB) treatments assess the decline, during the first few days to weeks of treatment, in colony forming unit (CFU) count of Mycobacterium tuberculosis in the sputum of patients with smear-microscopy-positive pulmonary TB. Profiles over time of CFU data have conventionally been modeled using linear, bilinear, or bi-exponential regression. We propose a new biphasic nonlinear regression model for CFU data that comprises linear and bilinear regression models as special cases and is more flexible than bi-exponential regression models. A Bayesian nonlinear mixed-effects (NLME) regression model is fitted jointly to the data of all patients from a trial, and statistical inference about the mean EBA of TB treatments is based on the Bayesian NLME regression model. The posterior predictive distribution of relevant slope parameters of the Bayesian NLME regression model provides insight into the nature of the EBA of TB treatments; specifically, the posterior predictive distribution allows one to judge whether treatments are associated with monolinear or bilinear decline of log(CFU) count, and whether CFU count initially decreases fast, followed by a slower rate of decrease, or vice versa. PMID:25322214

  11. Ambroxol inhibits mucoid conversion of Pseudomonas aeruginosa and contributes to the bactericidal activity of ciprofloxacin against mucoid P. aeruginosa biofilms.

    PubMed

    Wang, Wenlei; Yu, Jialin; He, Yu; Wang, Zhengli; Li, Fang

    2016-07-01

    Pseudomonas aeruginosa is an opportunistic human pathogen that can cause severe infections in immunocompromised individuals. Because it forms biofilms, which protect against host immune attack and increase resistance to conventional antibiotics, mucoid P. aeruginosa is nearly impossible to eradicate. Moreover, mucoid conversion of P. aeruginosa in cystic fibrosis (CF) patients leads to poor outcomes. This conversion is mainly due to mucA gene mutation, which is thought to be induced by polymorphonuclear leukocytes (PMNs) and the reactive oxygen species they release. Ambroxol, a mucolytic agent with antioxidant characteristics, is used clinically, and this compound has recently been demonstrated to possess anti-biofilm properties. In this study, we found that ambroxol inhibits the H2 O2 -mediated conversion of P. aeruginosa from a non-mucoid to a mucoid phenotype, an effect that is due to its antioxidant property against H2 O2 . Furthermore, the bactericidal activity of ciprofloxacin against mucoid P. aeruginosa biofilms was increased in vitro when used in combination with ambroxol.

  12. Electropositive charge in alpha-defensin bactericidal activity: functional effects of Lys-for-Arg substitutions vary with the peptide primary structure.

    PubMed

    Llenado, R Alan; Weeks, Colby S; Cocco, Melanie J; Ouellette, André J

    2009-11-01

    Cationic amino acids contribute to alpha-defensin bactericidal activity. Curiously, although Arg and Lys have equivalent electropositive charges at neutral pH, alpha-defensins contain an average of nine Arg residues per Lys residue. To investigate the role of high alpha-defensin Arg content, all Arg residues in mouse Paneth cell alpha-defensin cryptdin 4 (Crp4) and rhesus myeloid alpha-defensin 4 (RMAD-4) were replaced with Lys to prepare (R/K)-Crp4 and (R/K)-RMAD-4, respectively. Lys-for-Arg replacements in Crp4 attenuated bactericidal activity and slowed the kinetics of Escherichia coli ML35 cell permeabilization, and (R/K)-Crp4 required longer exposure times to reduce E. coli cell survival. In marked contrast, Lys substitutions in RMAD-4 improved microbicidal activity against certain bacteria and permeabilized E. coli more effectively. Therefore, Arg-->Lys substitutions attenuated activity in Crp4 but not in RMAD-4, and the functional consequences of Arg-->Lys replacements in alpha-defensins are dependent on the peptide primary structure. In addition, the bactericidal effects of (R/K)-Crp4 and (R/K)-RMAD-4 were more sensitive to inhibition by NaCl than those of the native peptides, suggesting that the high Arg content of alpha-defensins may be under selection to confer superior microbicidal function under physiologic conditions.

  13. Destabilization of α-Helical Structure in Solution Improves Bactericidal Activity of Antimicrobial Peptides: Opposite Effects on Bacterial and Viral Targets

    PubMed Central

    Morris, Christopher J.; Fox, Marc A.; Gumbleton, Mark; Beck, Konrad

    2016-01-01

    We have previously examined the mechanism of antimicrobial peptides on the outer membrane of vaccinia virus. We show here that the formulation of peptides LL37 and magainin-2B amide in polysorbate 20 (Tween 20) results in greater reductions in virus titer than formulation without detergent, and the effect is replicated by substitution of polysorbate 20 with high-ionic-strength buffer. In contrast, formulation with polysorbate 20 or high-ionic-strength buffer has the opposite effect on bactericidal activity of both peptides, resulting in lesser reductions in titer for both Gram-positive and Gram-negative bacteria. Circular dichroism spectroscopy shows that the differential action of polysorbate 20 and salt on the virucidal and bactericidal activities correlates with the α-helical content of peptide secondary structure in solution, suggesting that the virucidal and bactericidal activities are mediated through distinct mechanisms. The correlation of a defined structural feature with differential activity against a host-derived viral membrane and the membranes of both Gram-positive and Gram-negative bacteria suggests that the overall helical content in solution under physiological conditions is an important feature for consideration in the design and development of candidate peptide-based antimicrobial compounds. PMID:26824944

  14. Synergy between RU 28965 (roxithromycin) and human neutrophils for bactericidal activity in vitro.

    PubMed Central

    Labro, M T; Amit, N; Babin-Chevaye, C; Hakim, J

    1986-01-01

    The in vitro effects of RU 28965 (roxithromycin), a new semisynthetic macrolide, on human neutrophil activity were compared with those of erythromycin. RU 28965, at a concentration as low as 0.1 microgram/ml, significantly enhanced the phagocytosis and killing of Staphylococcus aureus by neutrophils. Erythromycin displayed a less stimulating effect in a dose-dependent manner. Phagocytosis of Klebsiella pneumoniae was also increased after incubation of neutrophils with RU 28965, but killing was not altered. Neutrophil chemotaxis, myeloperoxidase activity, and O2 consumption were unchanged in the presence of RU 28965. PMID:3019233

  15. Silver nanoparticles strongly enhance and restore bactericidal activity of inactive antibiotics against multiresistant Enterobacteriaceae.

    PubMed

    Panáček, Aleš; Smékalová, Monika; Večeřová, Renata; Bogdanová, Kateřina; Röderová, Magdaléna; Kolář, Milan; Kilianová, Martina; Hradilová, Šárka; Froning, Jens P; Havrdová, Markéta; Prucek, Robert; Zbořil, Radek; Kvítek, Libor

    2016-06-01

    Bacterial resistance to conventional antibiotics is currently one of the most important healthcare issues, and has serious negative impacts on medical practice. This study presents a potential solution to this problem, using the strong synergistic effects of antibiotics combined with silver nanoparticles (NPs). Silver NPs inhibit bacterial growth via a multilevel mode of antibacterial action at concentrations ranging from a few ppm to tens of ppm. Silver NPs strongly enhanced antibacterial activity against multiresistant, β-lactamase and carbapenemase-producing Enterobacteriaceae when combined with the following antibiotics: cefotaxime, ceftazidime, meropenem, ciprofloxacin and gentamicin. All the antibiotics, when combined with silver NPs, showed enhanced antibacterial activity at concentrations far below the minimum inhibitory concentrations (tenths to hundredths of one ppm) of individual antibiotics and silver NPs. The enhanced activity of antibiotics combined with silver NPs, especially meropenem, was weaker against non-resistant bacteria than against resistant bacteria. The double disk synergy test showed that bacteria produced no β-lactamase when treated with antibiotics combined with silver NPs. Low silver concentrations were required for effective enhancement of antibacterial activity against multiresistant bacteria. These low silver concentrations showed no cytotoxic effect towards mammalian cells, an important feature for potential medical applications.

  16. Bactericidal activity of alkaline salts of fatty acids towards bacteria associated with poultry processing

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Antibacterial activity of alkaline salts of caproic, caprylic, capric, lauric, and myristic acids were determined using the agar diffusion assay. A 0.5M concentration of each fatty acid (FA) was dissolved in 1.0 M potassium hydroxide (KOH), and pH of the mixtures was adjusted to 10.5 with citric aci...

  17. Enhanced Bactericidal Activity of Silver Thin Films Deposited via Aerosol-Assisted Chemical Vapor Deposition.

    PubMed

    Ponja, Sapna D; Sehmi, Sandeep K; Allan, Elaine; MacRobert, Alexander J; Parkin, Ivan P; Carmalt, Claire J

    2015-12-30

    Silver thin films were deposited on SiO2-barrier-coated float glass, fluorine-doped tin oxide (FTO) glass, Activ glass, and TiO2-coated float glass via AACVD using silver nitrate at 350 °C. The films were annealed at 600 °C and analyzed by X-ray powder diffraction, X-ray photoelectron spectroscopy, UV/vis/near-IR spectroscopy, and scanning electron microscopy. All the films were crystalline, and the silver was present in its elemental form and of nanometer dimension. The antibacterial activity of these samples was tested against Escherichia coli and Staphylococcus aureus in the dark and under UV light (365 nm). All Ag-deposited films reduced the numbers of E. coli by 99.9% within 6 h and the numbers of S. aureus by 99.9% within only 2 h. FTO/Ag reduced bacterial numbers of E. coli to below the detection limit after 60 min and caused a 99.9% reduction of S. aureus within only 15 min of UV irradiation. Activ/Ag reduced the numbers of S. aureus by 66.6% after 60 min and TiO2/Ag killed 99.9% of S. aureus within 60 min of UV exposure. More remarkably, we observed a 99.9% reduction in the numbers of E. coli within 6 h and the numbers of S. aureus within 4 h in the dark using our novel TiO2/Ag system.

  18. Bactericidal activity of N-chlorotaurine against biofilm-forming bacteria grown on metal disks.

    PubMed

    Coraça-Huber, Débora C; Ammann, Christoph G; Fille, Manfred; Hausdorfer, Johann; Nogler, Michael; Nagl, Markus

    2014-01-01

    Many orthopedic surgeons consider surgical irrigation and debridement with prosthesis retention as a treatment option for postoperative infections. Usually, saline solution with no added antimicrobial agent is used for irrigation. We investigated the activity of N-chlorotaurine (NCT) against various biofilm-forming bacteria in vitro and thereby gained significant information on its usability as a soluble and well-tolerated active chlorine compound in orthopedic surgery. Biofilms of Staphylococcus aureus were grown on metal alloy disks and in polystyrene dishes for 48 h. Subsequently, they were incubated for 15 min to 7 h in buffered solutions containing therapeutically applicable concentrations of NCT (1%, 0.5%, and 0.1%; 5.5 to 55 mM) at 37°C. NCT inactivated the biofilm in a time- and dose-dependent manner. Scanning electron microscopy revealed disturbance of the biofilm architecture by rupture of the extracellular matrix. Assays with reduction of carboxanilide (XTT) showed inhibition of the metabolism of the bacteria in biofilms. Quantitative cultures confirmed killing of S. aureus, Staphylococcus epidermidis, and Pseudomonas aeruginosa biofilms on metal alloy disks by NCT. Clinical isolates were slightly more resistant than ATCC type strains, but counts of CFU were reduced at least 10-fold by 1% NCT within 15 min in all cases. NCT showed microbicidal activity against various bacterial strains in biofilms. Whether this can be transferred to the clinical situation should be the aim of future studies.

  19. Bactericidal activity of black pepper, bay leaf, aniseed and coriander against oral isolates.

    PubMed

    Chaudhry, Nazia Masood Ahmed; Tariq, Perween

    2006-07-01

    Present investigation focused on antibacterial potential of aqueous decoction of black pepper (Piper nigrum L.), bay leaf (Laurus nobilis L.), aniseed (Pimpinella anisum L.), and coriander (Coriandum sativum L.) against 176 bacterial isolates belonging to 12 different genera of bacterial population isolated from oral cavity of 200 individuals. The disc diffusion technique was employed. Overall aqueous decoction of black pepper was the most bacterial-toxic exhibited 75% antibacterial activity as compared to aqueous decoction of bay leaf (53.4%) and aqueous decoction of aniseed (18.1%), at the concentration of 10 ml/disc. The aqueous decoction of coriander did not show any antibacterial effect against tested bacterial isolates.

  20. PHACOS, a functionalized bacterial polyester with bactericidal activity against methicillin-resistant Staphylococcus aureus

    PubMed Central

    Dinjaski, Nina; Fernández-Gutiérrez, Mar; Selvam, Shivaram; Parra-Ruiz, Francisco J.; Lehman, Susan M.; Román, Julio San; García, Ernesto; García, José L.; García, Andrés J.; Prieto, María Auxiliadora

    2013-01-01

    Biomaterial-associated infections represent a significant clinical problem, and treatment of these microbial infections is becoming troublesome due to the increasing number of antibiotic-resistant strains. Here, we report a naturally functionalized bacterial polyhydroxyalkanoate (PHACOS) with antibacterial properties. We demonstrate that PHACOS selectively and efficiently inhibits the growth of methicillin-resistant Staphylococcus aureus (MRSA) both in vitro and in vivo. This ability has been ascribed to the functionalized side chains containing thioester groups. Significantly less (3.2-fold) biofilm formation of S. aureus was detected on PHACOS compared to biofilms formed on control poly(3-hydroxyoctanoate-co-hydroxyhexanoate) and poly(ethylene terephthalate), but no differences were observed in bacterial adhesion among these polymers. PHACOS elicited minimal cytotoxic and inflammatory effects on murine macrophages and supported normal fibroblast adhesion. In vivo fluorescence imaging demonstrated minimal inflammation and excellent antibacterial activity for PHACOS compared to controls in an in vivo model of implant-associated infection. Additionally, reductions in neutrophils and macrophages in the vicinity of sterile PHACOS compared to sterile PHO implant were observed by immunohistochemistry. Moreover, a similar percentage of inflammatory cells was found in the tissue surrounding sterile PHACOS and S. aureus pre-colonized PHACOS implants, and these levels were significantly lower than S. aureus pre-colonized control polymers. These findings support a contact active surface mode of antibacterial action for PHACOS and establish this functionalized polyhydroxyalkanoate as an infection-resistant biomaterial. PMID:24094939

  1. Bactericidal activity and mechanism of Ti-doped BiOI microspheres under visible light irradiation.

    PubMed

    Liang, Jialiang; Deng, Jun; Li, Mian; Xu, Tongyan; Tong, Meiping

    2016-11-01

    Ti doped BiOI microspheres were successfully synthesized through a solvothermal method. The photocatalysts were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), high-resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS) and UV-vis diffuse reflectance spectra (DRS) spectroscopy, respectively. The as-synthesized microspheres had 3D hierarchical structures, and the morphologies and visible-light-driven (VLD) disinfection performances were found to be determined by the amount of loaded Ti. The incorporation of Ti in the lattice of BiOI broadened the band gap of BiOI and enhanced the VLD disinfection activity. Ti doped BiOI microspheres with the optimal Ti content exhibited excellent antibacterial performances against both representative Gram-negative and Gram-positive strains, which completely inactivated 3.0×10(7)CFUmL(-1)E. coli in 24min and 3.0×10(6)CFU mL(-1)S. aureus in 45min, respectively. Active species including h(+), e(-), O2(-) and H2O2 were found to play important roles in disinfection system. Moreover, the damage of cell membrane and emission of cytoplasm directly led to the inactivation.

  2. First-in-Class Inhibitors of Sulfur Metabolism with Bactericidal Activity against Non-Replicating M. tuberculosis

    PubMed Central

    Palde, Prakash B.; Bhaskar, Ashima; Pedrό Rosa, Laura E.; Madoux, Franck; Chase, Peter; Gupta, Vinayak; Spicer, Timothy; Scampavia, Louis; Singh, Amit; Carroll, Kate S.

    2016-01-01

    Development of effective therapies to eradicate persistent, slowly replicating M. tuberculosis (Mtb) represents a significant challenge to controlling the global TB epidemic. To develop such therapies, it is imperative to translate information from metabolome and proteome adaptations of persistent Mtb into the drug discovery screening platforms. To this end, reductive sulfur metabolism is genetically and pharmacologically implicated in survival, pathogenesis, and redox homeostasis of persistent Mtb. Therefore, inhibitors of this pathway are expected to serve as powerful tools in its preclinical and clinical validation as a therapeutic target for eradicating persisters. Here, we establish a first functional HTS platform for identification of APS reductase (APSR) inhibitors, a critical enzyme in the assimilation of sulfate for the biosynthesis of cysteine and other essential sulfur-containing molecules. Our HTS campaign involving 38 350 compounds led to the discovery of three distinct structural classes of APSR inhibitors. A class of bioactive compounds with known pharmacology displayed potent bactericidal activity in wild-type Mtb as well as MDR and XDR clinical isolates. Top compounds showed markedly diminished potency in a conditional ΔAPSR mutant, which could be restored by complementation with Mtb APSR. Furthermore, ITC studies on representative compounds provided evidence for direct engagement of the APSR target. Finally, potent APSR inhibitors significantly decreased the cellular levels of key reduced sulfur-containing metabolites and also induced an oxidative shift in mycothiol redox potential of live Mtb, thus providing functional validation of our screening data. In summary, we have identified first-in-class inhibitors of APSR that can serve as molecular probes in unraveling the links between Mtb persistence, antibiotic tolerance, and sulfate assimilation, in addition to their potential therapeutic value. PMID:26524379

  3. Periowave demonstrates bactericidal activity against periopathogens and leads to improved clinical outcomes in the treatment of adult periodontitis

    NASA Astrophysics Data System (ADS)

    Street, Cale N.; Andersen, Roger; Loebel, Nicolas G.

    2009-02-01

    Periodontitis affects half of the U.S. population over 50, and is the leading cause of tooth loss after 35. It is believed to be caused by growth of complex bacterial biofilms on the tooth surface below the gumline. Photodynamic therapy, a technology used commonly in antitumor applications, has more recently been shown to exhibit antimicrobial efficacy. We have demonstrated eradication of the periopathogens Porphyromonas gingivalis, Fusobacterium nucleatum, and Aggregatibacter actinomycetemcomitans in vitro using PeriowaveTM; a commercial photodisinfection system. In addition, several clinical studies have now demonstrated the efficacy of this treatment. A pilot study in the U.S. showed that 68% of patients treated with PeriowaveTM adjunctively to scaling and root planing (SRP) showed clinical attachment level increase of >1 mm, as opposed to 30% with SRP alone. In a subsequent larger study, a second PeriowaveTM treatment 6 weeks after initial treatment led to pocket depth improvements of >1.5 mm in 89% of patients. Finally, in the most recent multicenter, randomized, examiner-blinded study conducted on 121 subjects in Canada, PeriowaveTM treatment produced highly significant gains in attachment level (0.88 mm vs. 0.57 mm; p=0.003) and pocket depth (0.87 mm vs. 0.63 mm; p=0.01) as compared to SRP alone. In summary, PeriowaveTM demonstrated strong bactericidal activity against known periopathogens, and treatment of periodontitis using this system produced significantly better clinical outcomes than SRP alone. This, along with the absence of any adverse events in patients treated to date demonstrates that PDT is a safe and effective treatment for adult chronic periodontitis.

  4. Plant-mediated synthesis of biosilver nanoparticles using Pandanus amaryllifolius extract and its bactericidal activity

    SciTech Connect

    Akhir, Rabiatuladawiyah Md.; Fairuzi, Afiza Ahmad; Ismail, Nur Hilwani

    2015-08-28

    In this work, we describe a cost effective, easily scaled up and environmental friendly technique for green synthesis of silver nanoparticles (AgNPs) from 5 mM AgNO{sub 3} solution using aqueous extract of Pandanus amaryllifolius (P. amaryllifolius) leaves as reducing agent. Biosynthesized silver nanoparticles was confirmed by sampling the reaction mixture at regular intervals and the absorption maxima was scanned by Ultraviolet-Visible (UV-Vis) spectroscopy at wavelength of 200-500 nm. Images from Field Emission Scanning Electron Microscope (FESEM) have shown that the silver nanoparticles are 17-30 nm in range and assembled in mostly spherical shape. Elemental composition analysis by using Energy Dispersive X-ray (EDX) confirmed the presence of silver. Low concentration of biosynthesized silver nanoparticles have been found to exhibit good antibacterial activity against Staphylococcus aureus bacteria with average mean diameter of zone of inhibition (ZOI) of 16 mm.

  5. Plant-mediated synthesis of biosilver nanoparticles using Pandanus amaryllifolius extract and its bactericidal activity

    NASA Astrophysics Data System (ADS)

    Akhir, Rabiatuladawiyah Md.; Fairuzi, Afiza Ahmad; Ismail, Nur Hilwani

    2015-08-01

    In this work, we describe a cost effective, easily scaled up and environmental friendly technique for green synthesis of silver nanoparticles (AgNPs) from 5 mM AgNO3 solution using aqueous extract of Pandanus amaryllifolius (P. amaryllifolius) leaves as reducing agent. Biosynthesized silver nanoparticles was confirmed by sampling the reaction mixture at regular intervals and the absorption maxima was scanned by Ultraviolet-Visible (UV-Vis) spectroscopy at wavelength of 200-500 nm. Images from Field Emission Scanning Electron Microscope (FESEM) have shown that the silver nanoparticles are 17-30 nm in range and assembled in mostly spherical shape. Elemental composition analysis by using Energy Dispersive X-ray (EDX) confirmed the presence of silver. Low concentration of biosynthesized silver nanoparticles have been found to exhibit good antibacterial activity against Staphylococcus aureus bacteria with average mean diameter of zone of inhibition (ZOI) of 16 mm.

  6. Ultrasonic emulsification of food-grade nanoemulsion formulation and evaluation of its bactericidal activity.

    PubMed

    Ghosh, Vijayalakshmi; Mukherjee, Amitava; Chandrasekaran, Natarajan

    2013-01-01

    Basil oil (Ocimum basilicum) nanoemulsion was formulated using non-ionic surfactant Tween80 and water by ultrasonic emulsification method. Process of nanoemulsion development was optimized for parameters such as surfactant concentration and emulsification time to achieve minimum droplet diameter with high physical stability. Surfactant concentration was found to have a negative correlation with droplet diameter, whereas emulsification time had a positive correlation with droplet diameter and also with intrinsic stability of the emulsion. Stable basil oil nanoemulsion with droplet diameter 29.3 nm was formulated by ultrasonic emulsification for 15 min. Formulated nanoemulsion was evaluated for antibacterial activity against Escherichia coli by kinetics of killing experiment. Fluorescence microscopy and FT-IR results showed that nanoemulsion treatment resulted alteration in permeability and surface features of bacterial cell membrane.

  7. Formation of hydroxyl radicals contributes to the bactericidal activity of ciprofloxacin against Pseudomonas aeruginosa biofilms.

    PubMed

    Jensen, Peter Ø; Briales, Alejandra; Brochmann, Rikke P; Wang, Hengzhuang; Kragh, Kasper N; Kolpen, Mette; Hempel, Casper; Bjarnsholt, Thomas; Høiby, Niels; Ciofu, Oana

    2014-04-01

    Antibiotic-tolerant, biofilm-forming Pseudomonas aeruginosa has long been recognized as a major cause of chronic lung infections of cystic fibrosis patients. The mechanisms involved in the activity of antibiotics on biofilm are not completely clear. We have investigated whether the proposed induction of cytotoxic hydroxyl radicals (OH˙) during antibiotic treatment of planktonically grown cells may contribute to action of the commonly used antibiotic ciprofloxacin on P. aeruginosa biofilms. For this purpose, WT PAO1, a catalase deficient ΔkatA and a ciprofloxacin resistant mutant of PAO1 (gyrA), were grown as biofilms in microtiter plates and treated with ciprofloxacin. Formation of OH˙ and total amount of reactive oxygen species (ROS) was measured and viability was estimated. Formation of OH˙ and total ROS in PAO1 biofilms treated with ciprofloxacin was shown but higher levels were measured in ΔkatA biofilms, and no ROS production was seen in the gyrA biofilms. Treatment with ciprofloxacin decreased the viability of PAO1 and ΔkatA biofilms but not of gyrA biofilms. Addition of thiourea, a OH˙ scavenger, decreased the OH˙ levels and killing of PAO1 biofilm. Our study shows that OH˙ is produced by P. aeruginosa biofilms treated with ciprofloxacin, which may contribute to the killing of biofilm subpopulations.

  8. Bactericidal and Fungicidal Activity in the Gas Phase of Sodium Dichloroisocyanurate (NaDCC).

    PubMed

    Proto, Antonio; Zarrella, Ilaria; Cucciniello, Raffaele; Pironti, Concetta; De Caro, Francesco; Motta, Oriana

    2016-08-01

    Sodium dichloroisocyanurate (NaDCC) is usually employed as a disinfectant for the treatment of water, environmental surfaces and medical equipment principally for its effectiveness as a microbicide agent. In this study, we explore the possibility of a new use for NaDCC by investigating the microbicidal activity of chlorine, which derives from the hydrolysis of NaDCC mediated by air humidity, and by testing its effect on the neutralization of microbes present in domestic waste. NaDCC was inserted in a plastic garbage can where LB agar plates, with different dilutions of a known title of four different microorganisms (Escherichia coli, Staphylococcus aureus, Debaryomyces hansenii and Aspergillus brasiliensis), were weakly inserted. The molecular chlorine (Cl2) levels present in the garbage can were quantified using an iodometric titration. The gas emitted in the garbage can presented a strong microbicide effect, inhibiting the proliferation of all four microorganisms and for four consecutive weeks, thus showing that NaDCC hydrolysis, mediated by air humidity, is able to ensure the decontamination of restricted environments, avoiding the proliferation of both Gram-positive and Gram-negative bacteria as well as fungi.

  9. Cytotoxicity, Bactericidal, and Antioxidant Activity of Sodium Alginate Hydrosols Treated with Direct Electric Current

    PubMed Central

    Król, Żaneta; Marycz, Krzysztof; Kulig, Dominika; Marędziak, Monika; Jarmoluk, Andrzej

    2017-01-01

    The aim of the study was to investigate the effect of using direct electric current (DC) of 0, 200, and 400 mA for five minutes on the physiochemical properties, cytotoxicity, antibacterial, and antioxidant activity of sodium alginate hydrosols with different sodium chloride concentrations. The pH, oxidation-reduction potential (ORP), electrical conductivity (EC), and available chlorine concentration (ACC) were measured. The effect of sodium alginate hydrosols treated with DC on Staphylococcus aureus, Listeria monocytogenes, Bacillus cereus, Micrococcus luteus, Escherichia coli, Salmonella enteritidis, Yersinia enterocolitica, Pseudomonas fluorescence, and RAW 264.7 and L929 cells was investigated. Subsequently, the antioxidant properties of hydrosols were evaluated by determining the scavenging ability of 1,1-diphenyl-2-picrylhydrazyl free radical (DPPH) and ferric reducing antioxidant power (FRAP). The results have shown that after applying 400 mA in hydrosol samples with 0.1% and 0.2% NaCl all tested bacteria were inactivated. The ACC concentration of C400 samples with NaCl was equal to 13.95 and 19.71 mg/L, respectively. The cytotoxicity analysis revealed that optimized electric field conditions and the addition of sodium chloride allow for the avoidance of toxicity effects on normal cells without disturbing the antibacterial effects. Due to the presence of oxidizing substances, the DPPH of variants treated with DC was lower than the DPPH of control samples. PMID:28327520

  10. Bactericidal activity of copper and niobium-alloyed austenitic stainless steel.

    PubMed

    Baena, M I; Márquez, M C; Matres, V; Botella, J; Ventosa, A

    2006-12-01

    Biofouling and microbiologically influenced corrosion are processes of material deterioration that originate from the attachment of microorganisms as quickly as the material is immersed in a nonsterile environment. Stainless steels, despite their wide use in different industries and as appliances and implant materials, do not possess inherent antimicrobial properties. Changes in hygiene legislation and increased public awareness of product quality makes it necessary to devise control methods that inhibit biofilm formation or to act at an early stage of the biofouling process and provide the release of antimicrobial compounds on a sustainable basis and at effective level. These antibacterial stainless steels may find a wide range of applications in fields, such as kitchen appliances, medical equipment, home electronics, and tools and hardware. The purpose of this study was to obtain antibacterial stainless steel and thus mitigate the microbial colonization and bacterial infection. Copper is known as an antibacterial agent; in contrast, niobium has been demonstrated to improve the antimicrobial effect of copper by stimulating the formation of precipitated copper particles and its distribution in the matrix of the stainless steel. Thus, we obtained slides of 3.8% copper and 0.1% niobium alloyed stainless steel; subjected them to three different heat treatment protocols (550 degrees C, 700 degrees C, and 800 degrees C for 100, 200, 300, and 400 hours); and determined their antimicrobial activities by using different initial bacterial cell densities and suspending solutions to apply the bacteria to the stainless steels. The bacterial strain used in these experiments was Escherichia coli CCM 4517. The best antimicrobial effects were observed in the slides of stainless steel treated at 700 degrees C and 800 degrees C using an initial cell density of approximately 10(5) cells ml(-1) and phosphate-buffered saline as the solution in which the bacteria came into contact with

  11. Bactericidal activities of woven cotton and nonwoven polypropylene fabrics coated with hydroxyapatite-binding silver/titanium dioxide ceramic nanocomposite “Earth-plus”

    PubMed Central

    Kasuga, Eriko; Kawakami, Yoshiyuki; Matsumoto, Takehisa; Hidaka, Eiko; Oana, Kozue; Ogiwara, Naoko; Yamaki, Dai; Sakurada, Tsukasa; Honda, Takayuki

    2011-01-01

    Background Bacteria from the hospital environment, including linens and curtains, are often responsible for hospital-associated infections. The aim of the present study was to evaluate the bactericidal effects of fabrics coated with the hydroxyapatite-binding silver/titanium dioxide ceramic nanocomposite “Earth-plus”. Methods Bactericidal activities of woven and nonwoven fabrics coated with Earth-plus were investigated by the time-kill curve method using nine bacterial strains, including three Staphylococcus aureus, three Escherichia coli, and three Pseudomonas aeruginosa strains. Results The numbers of viable S. aureus and E. coli cells on both fabrics coated with Earth-plus decreased to below 2 log10 colony-forming units/mL in six hours and reached the detection limit in 18 hours. Viable cell counts of P. aeruginosa on both fabrics coated with Earth-plus could not be detected after 3–6 hours. Viable cells on woven fabrics showed a more rapid decline than those on nonwoven fabrics. Bacterial cell counts of the nine strains on fabrics without Earth-plus failed to decrease even after 18 hours. Conclusion Woven cotton and nonwoven polypropylene fabrics were shown to have excellent antibacterial potential. The woven fabric was more bactericidal than the nonwoven fabric. PMID:21931489

  12. Concentrations in plasma, urinary excretion, and bactericidal activity of linezolid (600 milligrams) versus those of ciprofloxacin (500 milligrams) in healthy volunteers receiving a single oral dose.

    PubMed

    Wagenlehner, Florian M E; Wydra, Stephan; Onda, Hajime; Kinzig-Schippers, Martina; Sörgel, Fritz; Naber, Kurt G

    2003-12-01

    In a randomized crossover study, 12 volunteers (6 males, 6 females) received a single oral dose of 600 mg of linezolid or 500 mg of ciprofloxacin to assess the concentrations in plasma (up to 24 h), urinary excretion (by high-pressure liquid chromatography), and bactericidal titers in urine (UBT) at intervals up to 120 h. The mean maximum concentration of linezolid in plasma was 13.1 mg/liter, and that of ciprofloxacin was 2.46 mg/liter. The median cumulative levels of renal excretion of the administered dose of the parent drug were 44% for linezolid (range, 28 to 47%; mean +/- standard deviation, 40% +/- 7.8%) and 43% for ciprofloxacin (range, 20 to 56%; mean +/- standard deviation, 40% +/- 9.3%). The UBTs, i.e., the highest twofold dilution (with antibiotic-free urine used as the diluent) of urine that was still bactericidal, were determined for a reference strain and five gram-positive clinical uropathogens for which the MICs of linezolid and ciprofloxacin were as follows: Staphylococcus aureus ATCC 27278, 2 and 0.25 mg/liter, respectively; Staphylococcus aureus (methicillin susceptible), 1 and 16 mg/liter, respectively; Staphylococcus aureus (methicillin resistant), 2 and 64 mg/liter, respectively; Staphylococcus saprophyticus (methicillin susceptible), 1 and 0.25 mg/liter, respectively; Enterococcus faecalis, 2 and 1 mg/liter, respectively; and Enterococcus faecium, 2 and 1 mg/liter, respectively. The median UBTs of linezolid measured within the first 6 h were 1:96 for each of the two enterococcal strains and between 1:128 and 1:256 for the four staphylococcal strains. The median UBTs of ciprofloxacin were 1:64 for the two enterococcal strains; between 1:384 and 1:512 for the two ciprofloxacin-susceptible strains; and 1 (bactericidal activity of undiluted urine only) and 1:2 for the two resistant staphylococcal strains, respectively. The areas under the UBT-time curve (AUBT) for linezolid and ciprofloxacin showed no statistically significant (P<0

  13. Bactericidal effect of Fe2+, ceruloplasmin, and phosphate.

    PubMed

    Klebanoff, S J

    1992-06-01

    Fe2+, when combined with ceruloplasmin or phosphate, was bactericidal to Escherichia coli at pH 5.0, and when Fe2+, ceruloplasmin, and phosphate were combined, a bactericidal effect was observed under conditions, i.e., short incubation period, in which Fe2+ plus ceruloplasmin and Fe2+ plus phosphate were ineffective. Bactericidal activity increased with the ceruloplasmin or phosphate concentration to a maximum and then decreased as their concentration was further increased. Fe2+ was oxidized in the presence of ceruloplasmin, phosphate, or, in particular, a combination of the two. A bactericidal effect was observed when there was only a partial loss of Fe2+, with more extensive oxidation resulting in a loss of bactericidal activity. The bactericidal effect of Fe2+ plus ceruloplasmin and/or phosphate was unaffected by catalase or superoxide dismutase and was not associated with iodination. Fe-EDTA was also bactericidal at an Fe2+: EDTA molar ratio of 1:0.5, where Fe2+ was partially oxidized. However, in contrast to Fe2+ plus ceruloplasmin and/or phosphate, bactericidal activity was inhibited by catalase and was associated with iodination. Combinations of Fe2+ and Fe3+ were not bactericidal under the conditions employed. A requirement for Fe2+ plus either a product of Fe2+ oxidation or an iron ceruloplasmin and/or phosphate chelate for bactericidal activity is proposed.

  14. Natural product derivatives with bactericidal activity against Gram-positive pathogens including methicillin-resistant Staphylococcus aureus and vancomycin-resistant Enterococcus faecalis.

    PubMed

    Phillips, Joshua B; Smith, Adrienne E; Kusche, Brian R; Bessette, Bradley A; Swain, P Whitney; Bergmeier, Stephen C; McMills, Mark C; Wright, Dennis L; Priestley, Nigel D

    2010-10-01

    We have shown that the intentional engineering of a natural product biosynthesis pathway is a useful way to generate stereochemically complex scaffolds for use in the generation of combinatorial libraries that capture the structural features of both natural products and synthetic compounds. Analysis of a prototype library based upon nonactic acid lead to the discovery of triazole-containing nonactic acid analogs, a new structural class of antibiotic that exhibits bactericidal activity against drug resistant, Gram-positive pathogens including Staphylococcus aureus and Enterococcus faecalis.

  15. THE BACTERICIDAL ACTION OF SYNTHETIC DETERGENTS.

    PubMed

    Baker, Z; Harrison, R W; Miller, B F

    1941-11-30

    1. The bactericidal action of a number of anionic and cationic synthetic detergents on four Gram-positive and three Gram-negative bacteria has been investigated. 2. Cationic detergents, as a group, were found to exhibit marked bactericidal effects on Gram-positive microorganisms and somewhat less pronounced action on Gram-negative organisms. 3. The anionic detergents were germicidal only against the Gram-positive organisms, and they were considerably less effective than the cationic compounds. Of the anionic detergents, the most active one was an alkyl sulfate derived from a branched-chain, secondary alcohol. 4. Correlations between bactericidal action and inhibition of bacterial metabolism, and also between bactericidal action and chemical structure of the detergents are discussed.

  16. Randomized dose-ranging study of the 14-day early bactericidal activity of bedaquiline (TMC207) in patients with sputum microscopy smear-positive pulmonary tuberculosis.

    PubMed

    Diacon, Andreas H; Dawson, Rodney; Von Groote-Bidlingmaier, Florian; Symons, Gregory; Venter, Amour; Donald, Peter R; Conradie, Almari; Erondu, Ngozi; Ginsberg, Ann M; Egizi, Erica; Winter, Helen; Becker, Piet; Mendel, Carl M

    2013-05-01

    Bedaquiline is a new antituberculosis agent targeting ATP synthase. This randomized, double-blinded study enrolling 68 sputum smear-positive pulmonary tuberculosis patients evaluated the 14-day early bactericidal activity of daily doses of 100 mg, 200 mg, 300 mg, and 400 mg bedaquiline, preceded by loading doses of 200 mg, 400 mg, 500 mg, and 700 mg, respectively, on the first treatment day and 100 mg, 300 mg, 400 mg, and 500 mg on the second treatment day. All groups showed activity with a mean (standard deviation) daily fall in log10 CFU over 14 days of 0.040 (0.068), 0.056 (0.051), 0.077 (0.064), and 0.104 (0.077) in the 100-mg, 200-mg, 300-mg, and 400-mg groups, respectively. The linear trend for dose was significant (P = 0.001), and activity in the 400-mg dose group was greater than that in the 100-mg group (P = 0.014). All of the bedaquiline groups showed significant bactericidal activity that was continued to the end of the 14-day evaluation period. The finding of a linear trend for dose suggests that the highest dose compatible with safety considerations should be taken forward to longer-term clinical studies.

  17. Bactericidal activity and silver release of porous ceramic candle filter prepared by sintering silica with silver nanoparticles/zeolite for water disinfection

    NASA Astrophysics Data System (ADS)

    Trinh Nguyen, Thuy Ai; Phu Dang, Van; Duy Nguyen, Ngoc; Le, Anh Quoc; Thanh Nguyen, Duc; Hien Nguyen, Quoc

    2014-09-01

    Porous ceramic candle filters (PCCF) were prepared by sintering silica from rice husk with silver nanoparticles (AgNPs)/zeolite A at about 1050 °C to create bactericidal PCCF/AgNPs for water disinfection. The silver content in PCCF/AgNPs was of 300-350 mg kg-1 determined by inductively coupled plasma-atomic emission spectroscopy (ICP-AES) and the average pore size of PCCF/AgNPs was of 50-70 Å measured by Brunauer-Emmett-Teller (BET) method. The bactericidal activity and silver release of PCCF/AgNPs have been investigated by flow test with water flow rate of 5 L h-1 and initial inoculation of E. coli in inlet water of 106 CFU/100 mL. The volume of filtrated water was collected up to 500 L. Results showed that the contamination of E. coli in filtrated water was <1 CFU/100 mL and the content of silver released from PCCF/AgNPs into filtrated water was <1 μg L-1, it is low, far under the WHO guideline of 100 μg L-1 at maximum for drinking water. Based on the content of silver in PCCF/AgNPs and in filtrated water, it was estimated that one PCCF/AgNPs could be used to filtrate of ˜100 m3 water. Thus, as-prepared PCCF/AgNPs releases low content of silver into water and shows effectively bactericidal activity that is promising to apply as point-of-use water treatment technology for drinking water disinfection.

  18. Bactericidal activity of moxifloxacin compared to grepafloxacin and clarithromycin against Streptococcus pneumoniae and Streptococcus pyogenes investigated using an in vitro pharmacodynamic model.

    PubMed

    Esposito, S; Noviello, S; Ianniello, F

    2000-12-01

    The aim of the present investigation was to study and compare the killing activity of two new fluoroquinolone compounds, moxifloxacin and grepafloxacin, and a new generation macrolide, clarithromycin, against three clinical isolates of Streptococcus pneumoniae (penicillin-susceptible, -intermediate and -resistant) and two Streptococcus pyogenes (erythromycin-susceptible and -resistant) strains by simulating their human pharmacokinetics in a pharmacodynamic model. Results were achieved by measuring the reduction in viable bacterial count during the 24-h experimental period. All three antimicrobials led to a continuous reduction in the bacterial counts of penicillin-susceptible S. pneumoniae and erythromycin-susceptible S. pyogenes strains, the maximal reduction observed after 8-10 hours being 5-6 logs for moxifloxacin and 3 logs for grepafloxacin; clarithromycin exhibited a similar reduction of 5 logs only after 24 h. No regrowth was observed for any strain after 24 h with any of the antibiotics. The bactericidal activity of both the fluoroquinolones was not affected by penicillin resistance of S. pneumoniae and erythromycin resistance of S. pyogenes. In contrast, clarithromycin was not able to reduce the bacterial count of penicillin-resistant S. pneumoniae and erythromycin-resistant S. pyogenes strains. Moxifloxacin exhibited, within 24 h, higher and faster bactericidal activity than grepafloxacin and clarithromycin against S. pneumoniae, and was not affected by penicillin resistance. These results suggest that moxifloxacin is a promising new agent for treatment of streptococcal infections.

  19. Terminal carbohydrates abundance, immune related enzymes, bactericidal activity and physico-chemical parameters of the Senegalese sole (Solea senegalensis, Kaup) skin mucus.

    PubMed

    Guardiola, Francisco A; Cuartero, María; Del Mar Collado-González, María; Díaz Baños, F Guillermo; Cuesta, Alberto; Moriñigo, Miguel Ángel; Esteban, M Ángeles

    2017-01-01

    Recently, interest in mucosal surfaces, more specifically fish skin and its secreted mucus, has greatly increased among immunologists. The abundance of terminal carbohydrates, several enzymes (proteases, lysozyme, peroxidase, alkaline phosphatase, esterases and ceruloplasmin), bactericidal activity against fish pathogenic and non-pathogenic bacteria and several physico-chemical parameters (protein concentration, pH, conductivity, redox potential, osmolarity, density and viscosity) in the skin mucus of Senegalese sole (Solea senegalensis, Kaup) have been evaluated. Present results evidence the abundance of N-acetylneuraminic acid, mannose, glucose and N-acetyl-galactosamine in skin mucus. The levels of lysozyme, proteases, esterases and alkaline phosphatase were very similar (from 20 to 30 Units mg(-1) protein). However, 93 Units mg(-1) protein were detected of ceruloplasmin and only 4'88 Units mg(-1) protein of peroxidase. Skin mucus of S. senegalensis showed high bactericidal activity against the tested pathogen bacteria but weak activity against non-pathogenic bacteria. Finally, a clear relationship between mucus density and temperature was detected, while viscosity showed a direct shear- and temperature-dependent behaviour. These results could be useful for better understanding the role of the skin mucus as a key component of the innate immune system, as well as, for elucidating possible relationships between biological and physico-chemical parameters and disease susceptibility.

  20. Daptomycin Bactericidal Activity and Correlation between Disk and Broth Microdilution Method Results in Testing of Staphylococcus aureus Strains with Decreased Susceptibility to Vancomycin

    PubMed Central

    Sader, Helio S.; Fritsche, Thomas R.; Jones, Ronald N.

    2006-01-01

    A total of 207 Staphylococcus aureus strains, including 105 well-characterized strains with decreased susceptibility to vancomycin (17 vancomycin-intermediate S. aureus [VISA] and 88 heteroresistant VISA [hVISA] strains) and 102 wild-type methicillin-resistant S. aureus (MRSA-WT) strains were tested by reference/standardized broth microdilution and disk diffusion methods, as well as by Etest (AB BIODISK, Solna, Sweden), against daptomycin and vancomycin. The lowest concentration of antimicrobial agent that killed ≥99.9% of the initial inoculum was defined as the minimum bactericidal concentration (MBC) endpoint, and time-kill curves were performed in selected strains to further evaluate bactericidal activity. All MRSA-WT and hVISA strains were inhibited by ≤1 μg/ml of daptomycin, while the VISA strains showed slightly higher daptomycin MICs (range, 0.5 to 4 μg/ml). All daptomycin MBC results were at the MIC or twofold higher. In contrast, 14.7% of MRSA-WT, 69.3% of hVISA, and all VISA strains showed a vancomycin MBC/MIC ratio of ≥32 or an MBC of ≥16 μg/ml (tolerant). The correlation coefficients between broth microdilution and disk diffusion method results were low for daptomycin (0.07) and vancomycin (0.11). Eight (3.8%) strains (all hVISA or VISA) were “nonsusceptible” to daptomycin by broth microdilution methods but susceptible by the disk diffusion method. For vancomycin, 35 (16.9%) strains were nonsusceptible by broth microdilution methods but susceptible by disk diffusion methods. In conclusion, daptomycin was highly bactericidal against S. aureus strains, and its bactericidal activity was not affected by decreased susceptibility to vancomycin. In contrast, many (one in seven) contemporary MRSA-WT, the majority of hVISA, and all VISA strains showed vancomycin MBC/MIC ratios consistent with tolerance, a predictor of poor clinical response. Disk diffusion tests generally failed to detect strains categorized as nonsusceptible to daptomycin or

  1. A Novel Means of Self-Protection, Unrelated to Toxin Activation, Confers Immunity to the Bactericidal Effects of the Enterococcus faecalis Cytolysin

    PubMed Central

    Coburn, Phillip S.; Hancock, Lynn E.; Booth, Mary C.; Gilmore, Michael S.

    1999-01-01

    Enterococcus faecalis has become a pervasive clinical problem due to the emergence of resistance to most antibiotics. The cytolysin of E. faecalis is a novel bacterial toxin that contributes to the severity of disease. It consists of two structural subunits, which together possess both hemolytic and bactericidal activity. Both toxin subunits are encoded in a complex operon frequently harbored on pheromone-responsive plasmids. E. faecalis strains lacking such plasmids are susceptible to the bactericidal effects of the cytolysin. A novel cytolysin immunity determinant at the 3′ end of the pAD1 cytolysin operon is described in the present study. Deletion analysis and specific mutagenesis isolated the immunity function to a single open reading frame. Specific mutagenesis experiments demonstrate that cytolysin immunity is unrelated to cytolysin activator (CylA) expression as previously proposed. Cytolysin immunity is, however, encoded on the same transcript as and 3′ to CylA, and previous associations between immunity and CylA can be ascribed to the polar behavior of Tn917 insertion. PMID:10377111

  2. Bactericidal activity of juvenile chinook salmon macrophages against Aeromonas salmonicida after exposure to live or heat-killed Renibacterium salmoninarum or to soluble proteins produced by R. salmoninarum

    USGS Publications Warehouse

    Siegel, D.C.; Congleton, J.L.

    1997-01-01

    Macrophages isolated from the anterior kidney of juvenile chinook salmon Oncorhynchus tshawytscha in 96-well microtiter plates were exposed for 72 h to 0, 105, or 106 live or heat-killed Renibacterium salmoninarum cells per well or to 0, 0.1, 1.0, or 10 ??g/mL of R. salmoninarum soluble proteins. After treatment, the bactericidal activity of the macrophages against Aerornonas salmonicida was determined by a colorimetric assay based on the reduction of the tetrazolium dye MTT to formazan by viable bacteria. The MTT assay was modified to allow estimation of the percentage of bacteria killed by reference to a standard curve relating the number of bacteria added to microtiter wells to absorbance by formazan at 600 nm. The live and heat-killed R. salmoninarum treatments significantly (P < 0.001) increased killing of A. salmonicida by chinook salmon macrophages. In each of the five trials, significantly (P < 0.05) greater increases in killing occurred after exposure to 105 R. salmoninarum cells than to 106 R. salmoninarum cells per well. In contrast, treatment of macrophages with 10 ??g/mL R. salmoninarum soluble proteins significantly (P < 0.001) decreased killing of A. salmonicida, but treatment with lower doses did not. These results show that the bactericidal activity of chinook salmon macrophages is stimulated by exposure to R. salmoninarum cells at lower dose levels but inhibited by exposure to R. salmoninarum cells or soluble proteins at higher dose levels.

  3. Superoxide Dismutase Activity, Hydrogen Peroxide Steady-State Concentration, and Bactericidal and Phagocytic Activities Against Moraxella bovis, in Neutrophils Isolated from Copper-Deficient Bovines.

    PubMed

    Cintia, Postma Gabriela; Leonardo, Minatel; Israel, Olivares Roberto Walter; Andrea, Schapira; Beatriz, Valdez Laura; Elena, Dallorso Maria

    2016-05-01

    Copper (Cu) deficiency increases occurrence of certain infectious diseases in animals, including infectious keratoconjunctivitis in bovines, a bacterial ocular inflammation caused by Moraxella bovis. Neutrophil leukocytes constitute the first phagocytic cells to arrive at infection sites for bacterial neutralization. The objective of this work was to evaluate whether the functionality of neutrophils against M. bovis is impaired in experimentally induced Cu deficiency in bovines using high molybdenum and sulfur levels in the diet. The Cu tissue values and the periocular achromotrichia observed in +Mo animals showed that the clinic phase of Cu deficiency was reached in this group. Instead, +Cu animals have not evidenced clinical signs or biochemical parameters of hypocuprosis. On the basis of our observations, we concluded that Cu deficiency has no effect on phagocytic and bactericidal activities of neutrophils against M. bovis. However, superoxide dismutase activity and peroxide hydrogen generation were significantly different between groups. Therefore, additional research to explain these results is merited to fully characterize the consequences of Cu status on the risk for infections under field conditions.

  4. Bactericidal Efficacy of Sanitizers Produced by Commercial Water Treatment Generators

    DTIC Science & Technology

    2009-04-01

    Tween 80, a non -reactive reagent with no bactericidal activity. 2.3.4 Numbers Control. To determine the number of recoverable bacteria, two coupons...TECHNICAL REPORT NATICK/TR-09/013 AD------ BACTERICIDAL EFFICACY OF SANITIZERS PRODUCED BY COMMERCIAL WATER TREATMENT GENERATORS by Edmund M. Powers...Engineering Center (NSRDEC), for bactericidal efficacy of their sanitizer on stainless steel surfaces. Sanitizers generated were Acid Electrolyzed Water (AEW

  5. Influence of the surface properties on bactericidal and fungicidal activity of magnetron sputtered Ti-Ag and Nb-Ag thin films.

    PubMed

    Wojcieszak, D; Mazur, M; Kaczmarek, D; Mazur, P; Szponar, B; Domaradzki, J; Kepinski, L

    2016-05-01

    In this study the comparative investigations of structural, surface and bactericidal properties of Ti-Ag and Nb-Ag thin films have been carried out. Ti-Ag and Nb-Ag coatings were deposited on silicon and fused silica substrates by magnetron co-sputtering method using innovative multi-target apparatus. The physicochemical properties of prepared thin films were examined with the aid of X-ray diffraction, grazing incidence X-ray diffraction, scanning electron microscopy, atomic force microscopy and X-ray photoelectron spectroscopy methods. Moreover, the wettability of the surface was determined. It was found that both, Ti-Ag and Nb-Ag thin films were nanocrystalline. In the case of Ag-Ti film presence of AgTi3 and Ag phases was identified, while in the structure of Nb-Ag only silver occurred in a crystal form. In both cases the average size of crystallites was ca. 11 nm. Moreover, according to scanning electron microscopy and atomic force microscopy investigations the surface of Nb-Ag thin films was covered with Ag-agglomerates, while Ti-Ag surface was smooth and devoid of silver particles. Studies of biological activity of deposited coatings in contact with Bacillus subtilis, Pseudomonas aeruginosa, Enterococcus hirae, Klebisiella pneumoniae, Escherichia coli, Staphylococcus aureus and Candida albicans were performed. It was found that prepared coatings were bactericidal and fungicidal even in a short term-contact, i.e. after 2 h.

  6. Dietary Myrtle (Myrtus communis L.) improved non-specific immune parameters and bactericidal activity of skin mucus in rainbow trout (Oncorhynchus mykiss) fingerlings.

    PubMed

    Mansouri Taee, Hadis; Hajimoradloo, Abdolmajid; Hoseinifar, Seyed Hossein; Ahmadvand, Hassan

    2017-03-19

    The present study examined the effects of dietary Myrtle (Myrtus communis L.) on non-specific immune parameters and bactericidal activity of skin mucus in rainbow trout (Oncorhynchus mykiss) fingerlings. Three hundred and sixty fingerlings (6.50 ± 0.55 g (were distributed in twelve cages (65 × 65 × 65 cm) with a metal framework. The study included four treatments repeated in triplicates. The treatments were feeding trouts with experimental diets containing different levels (0, 0.5, 1 and 1.5%) of Myrtle powder. The fingerlings were fed on experimental diet for sixty days and then skin mucus non-specific immune parameters as well as bactericidal activity were measured. At the end of the trial, the highest skin mucus soluble protein level was observed in group fed with 1.5% Myrtle (P < 0.05). The alkaline phosphatase (ALP) activity was significantly increased in fish groups fed 1 and 1.5% Myrtle compared with the control group (P < 0.05). However, evaluation of skin mucus lysozyme activity showed no significant difference between treatments and control group (P > 0.05). Also, no antibacterial activity was detected against Escherichia coli, Staphylococcus aureus and Salmonella enterica in all treatments and control group. Whereas skin mucus of rainbow trout showed antimicrobial activity against fish pathogens (Aeromonas hydrophila and Yersinia ruckeri) in 1 and 1.5% Myrtle treatments. These results indicated beneficial effects of dietary Myrtle on mucosal immune parameters of fingerling rainbow trout.

  7. An Inactivated Antibiotic-Exposed Whole-Cell Vaccine Enhances Bactericidal Activities Against Multidrug-Resistant Acinetobacter baumannii

    PubMed Central

    Shu, Meng-Hooi; MatRahim, NorAziyah; NorAmdan, NurAsyura; Pang, Sui-Ping; Hashim, Sharina H.; Phoon, Wai-Hong; AbuBakar, Sazaly

    2016-01-01

    Vaccination may be an alternative treatment for infection with multidrug-resistance (MDR) Acinetobacter baumannii. The study reported here evaluated the bactericidal antibody responses following immunization of mice using an inactivated whole-cell vaccine derived from antibiotic-exposed MDR A. baumannii (I-M28-47-114). Mice inoculated with I-M28-47 (non-antibiotic-exposed control) and I-M28-47-114 showed a high IgG antibody response by day 5 post-inoculation. Sera from mice inoculated with I-M28-47-114 collected on day 30 resulted in 80.7 ± 12.0% complement-mediated bacteriolysis in vitro of the test MDR A. baumannii treated with imipenem, which was a higher level of bacteriolysis over sera from mice inoculated with I-M28-47. Macrophage-like U937 cells eliminated 49.3 ± 11.6% of the test MDR A. baumannii treated with imipenem when opsonized with sera from mice inoculated with I-M28-47-114, which was a higher level of elimination than observed for test MDR A. baumannii opsonized with sera from mice inoculated with I-M28-47. These results suggest that vaccination with I-M28-47-114 stimulated antibody responses capable of mounting high bactericidal killing of MDR A. baumannii. Therefore, the inactivated antibiotic-exposed whole-cell vaccine (I-M28-47-114) has potential for development as a candidate vaccine for broad clearance and protection against MDR A. baumannii infections. PMID:26923424

  8. Honey Glycoproteins Containing Antimicrobial Peptides, Jelleins of the Major Royal Jelly Protein 1, Are Responsible for the Cell Wall Lytic and Bactericidal Activities of Honey

    PubMed Central

    Brudzynski, Katrina; Sjaarda, Calvin

    2015-01-01

    We have recently identified the bacterial cell wall as the cellular target for honey antibacterial compounds; however, the chemical nature of these compounds remained to be elucidated. Using Concavalin A- affinity chromatography, we found that isolated glycoprotein fractions (glps), but not flow-through fractions, exhibited strong growth inhibitory and bactericidal properties. The glps possessed two distinct functionalities: (a) specific binding and agglutination of bacterial cells, but not rat erythrocytes and (b) non-specific membrane permeabilization of both bacterial cells and erythrocytes. The isolated glps induced concentration- and time-dependent changes in the cell shape of both E. coli and B. subtilis as visualized by light and SEM microscopy. The appearance of filaments and spheroplasts correlated with growth inhibition and bactericidal effects, respectively. The time-kill kinetics showed a rapid, >5-log10 reduction of viable cells within 15 min incubation at 1xMBC, indicating that the glps-induced damage of the cell wall was lethal. Unexpectedly, MALDI-TOF and electrospray quadrupole time of flight mass spectrometry, (ESI-Q-TOF-MS/MS) analysis of glps showed sequence identity with the Major Royal Jelly Protein 1 (MRJP1) precursor that harbors three antimicrobial peptides: Jelleins 1, 2, and 4. The presence of high-mannose structures explained the lectin-like activity of MRJP1, while the presence of Jelleins in MRJP1 may explain cell wall disruptions. Thus, the observed damages induced by the MRJP1 to the bacterial cell wall constitute the mechanism by which the antibacterial effects were produced. Antibacterial activity of MRJP1 glps directly correlated with the overall antibacterial activity of honey, suggesting that it is honey’s active principle responsible for this activity. PMID:25830314

  9. Honey glycoproteins containing antimicrobial peptides, Jelleins of the Major Royal Jelly Protein 1, are responsible for the cell wall lytic and bactericidal activities of honey.

    PubMed

    Brudzynski, Katrina; Sjaarda, Calvin

    2015-01-01

    We have recently identified the bacterial cell wall as the cellular target for honey antibacterial compounds; however, the chemical nature of these compounds remained to be elucidated. Using Concavalin A-affinity chromatography, we found that isolated glycoprotein fractions (glps), but not flow-through fractions, exhibited strong growth inhibitory and bactericidal properties. The glps possessed two distinct functionalities: (a) specific binding and agglutination of bacterial cells, but not rat erythrocytes and (b) non-specific membrane permeabilization of both bacterial cells and erythrocytes. The isolated glps induced concentration- and time-dependent changes in the cell shape of both E. coli and B. subtilis as visualized by light and SEM microscopy. The appearance of filaments and spheroplasts correlated with growth inhibition and bactericidal effects, respectively. The time-kill kinetics showed a rapid, >5-log10 reduction of viable cells within 15 min incubation at 1xMBC, indicating that the glps-induced damage of the cell wall was lethal. Unexpectedly, MALDI-TOF and electrospray quadrupole time of flight mass spectrometry, (ESI-Q-TOF-MS/MS) analysis of glps showed sequence identity with the Major Royal Jelly Protein 1 (MRJP1) precursor that harbors three antimicrobial peptides: Jelleins 1, 2, and 4. The presence of high-mannose structures explained the lectin-like activity of MRJP1, while the presence of Jelleins in MRJP1 may explain cell wall disruptions. Thus, the observed damages induced by the MRJP1 to the bacterial cell wall constitute the mechanism by which the antibacterial effects were produced. Antibacterial activity of MRJP1 glps directly correlated with the overall antibacterial activity of honey, suggesting that it is honey's active principle responsible for this activity.

  10. Early bactericidal activity of rifabutin versus that of placebo in treatment of disseminated Mycobacterium avium complex bacteremia in AIDS patients.

    PubMed Central

    Dautzenberg, B; Castellani, P; Pellegrin, J L; Vittecoq, D; Truffot-Pernot, C; Pirotta, N; Sassella, D

    1996-01-01

    Rifabutin, 600 mg/day, was compared with a placebo in the early treatment of culture-proven Mycobacterium avium bacteremia in patients with AIDS. Following 14 days' treatment, bacteriological success, defined as a negative culture or a reduction in the number of CFU of M. avium organisms per milliliter of blood by a factor of > or = 0.5 log from the baseline, was observed in 7 of 10 (70%) evaluable rifabutin patients and in 1 of 13 (8%) evaluable placebo patients (P = 0.002). Rifabutin is active against M. avium as a single agent and can make a significant contribution to combination regimens for the treatment of disseminated M. avium infection in AIDS patients. PMID:8807071

  11. Bactericidal activities of essential oils of basil and sage against a range of bacteria and the effect of these essential oils on Vibrio parahaemolyticus.

    PubMed

    Koga, T; Hirota, N; Takumi, K

    1999-12-01

    Basil and sage essential oils were examined for bactericidal activity against a range of Gram-positive and Gram-negative bacteria by viable count determinations. Generally, Gram-positive bacteria showed higher resistance to basil and sage essential oils than Gram-negative bacteria. Vibrio species showed a high sensitivity to both essential oils. Stationary growth phase cells of selected bacteria showed higher resistance to these essential oils than exponential growth phase cells. Basil-resistant (b21) and sage-resistant (s20) strains of Vibrio parahaemolyticus were isolated. Both strains showed higher resistance to heat and H2O2 than parent strain. Conversely, heat-adapted V. parahaemolyticus also showed a higher resistance to these essential oils than nonadapted cells.

  12. Bactericidal activities of plant essential oils and some of their isolated constituents against Campylobacter jejuni, Escherichia coli, Listeria monocytogenes, and Salmonella enterica.

    PubMed

    Friedman, Mendel; Henika, Philip R; Mandrell, Robert E

    2002-10-01

    An improved method of sample preparation was used in a microplate assay to evaluate the bactericidal activity levels of 96 essential oils and 23 oil compounds against Campylobacter jejuni, Escherichia coli O157:H7, Listeria monocytogenes, and Salmonella enterica obtained from food and clinical sources. Bactericidal activity (BA50) was defined as the percentage of the sample in the assay mixture that resulted in a 50% decrease in CFU relative to a buffer control. Twenty-seven oils and 12 compounds were active against all four species of bacteria. The oils that were most active against C. jejuni (with BA50 values ranging from 0.003 to 0.009) were marigold, ginger root, jasmine, patchouli, gardenia, cedarwood, carrot seed, celery seed, mugwort, spikenard, and orange bitter oils; those that were most active against E. coli (with BA50 values ranging from 0.046 to 0.14) were oregano, thyme, cinnamon, palmarosa, bay leaf, clove bud, lemon grass, and allspice oils; those that were most active against L monocytogenes (with BA50 values ranging from 0.057 to 0.092) were gardenia, cedarwood, bay leaf, clove bud, oregano, cinnamon, allspice, thyme, and patchouli oils; and those that were most active against S. enterica (with BA50 values ranging from 0.045 to 0.14) were thyme, oregano, cinnamon, clove bud, allspice, bay leaf, palmarosa, and marjoram oils. The oil compounds that were most active against C. jejuni (with BA50 values ranging from 0.003 to 0.034) were cinnamaldehyde, estragole, carvacrol, benzaldehyde, citral, thymol, eugenol, perillaldehyde, carvone R, and geranyl acetate; those that were most active against E. coli (with BA50 values ranging from 0.057 to 0.28) were carvacrol, cinnamaldehyde, thymol, eugenol, salicylaldehyde, geraniol, isoeugenol, citral, perillaldehyde, and estragole; those that were most active against L monocytogenes (with BA50 values ranging from 0.019 to 0.43) were cinnamaldehyde, eugenol, thymol, carvacrol, citral, geraniol, perillaldehyde

  13. CD4+ T Cells Are as Protective as CD8+ T Cells against Rickettsia typhi Infection by Activating Macrophage Bactericidal Activity

    PubMed Central

    Moderzynski, Kristin; Papp, Stefanie; Rauch, Jessica; Heine, Liza; Kuehl, Svenja; Richardt, Ulricke; Fleischer, Bernhard; Osterloh, Anke

    2016-01-01

    Rickettsia typhi is an intracellular bacterium that causes endemic typhus, a febrile disease that can be fatal due to complications including pneumonia, hepatitis and meningoencephalitis, the latter being a regular outcome in T and B cell-deficient C57BL/6 RAG1-/- mice upon Rickettsia typhi infection. Here, we show that CD4+ TH1 cells that are generated in C57BL/6 mice upon R. typhi infection are as protective as cytotoxic CD8+ T cells. CD4+- as well as CD8+-deficient C57BL/6 survived the infection without showing symptoms of disease at any point in time. Moreover, adoptively transferred CD8+ and CD4+ immune T cells entered the CNS of C57BL/6 RAG1-/- mice with advanced infection and both eradicated the bacteria. However, immune CD4+ T cells protected only approximately 60% of the animals from death. They induced the expression of iNOS in infiltrating macrophages as well as in resident microglia in the CNS which can contribute to bacterial killing but also accelerate pathology. In vitro immune CD4+ T cells inhibited bacterial growth in infected macrophages which was in part mediated by the release of IFNγ. Collectively, our data demonstrate that CD4+ T cells are as protective as CD8+ T cells against R. typhi, provided that CD4+ TH1 effector cells are present in time to support bactericidal activity of phagocytes via the release of IFNγ and other factors. With regard to vaccination against TG Rickettsiae, our findings suggest that the induction of CD4+ TH1 effector cells is sufficient for protection. PMID:27875529

  14. Ceftaroline plus avibactam demonstrates bactericidal activity against pathogenic anaerobic bacteria in a one-compartment in vitro pharmacokinetic/pharmacodynamic model.

    PubMed

    Werth, Brian J; Rybak, Michael J

    2014-01-01

    Anaerobic pathogens are often associated with polymicrobial infections, such as diabetic foot infections. Patients with these infections are often treated with broad-spectrum, multidrug therapies targeting resistant Gram-positive bacteria, such as methicillin-resistant Staphylococcus aureus, as well as Gram-negative bacteria and anaerobes. The broad-spectrum, non-beta-lactam, beta-lactamase inhibitor avibactam has been combined with ceftaroline and may provide a single-product alternative for complicated polymicrobial infections. We compared the activity of ceftaroline-avibactam (CPA) to that of ertapenem (ERT) against common anaerobic pathogens in an in vitro pharmacokinetic/pharmacodynamic (PK/PD) model. Simulations of doses of ceftaroline-fosamil at 600 mg every 8 h (q8h) (maximum free drug concentration [fCmax], 17.04 mg/liter, and half-life [t1/2], 2.66 h) plus avibactam at 600 mg q8h (fCmax, 11.72 mg/liter, and t1/2, 1.8 h) and of ertapenem at 1 g q24h (fCmax, 13 mg/liter, and t1/2, 4 h) were evaluated against two strains of Bacteroides fragilis, one strain of Prevotella bivia, and one strain of Finegoldia magna in an anaerobic one-compartment in vitro PK/PD model over 72 h with a starting inoculum of ∼8 log10 CFU/ml. Bactericidal activity was defined as a reduction of ≥3 log10 CFU/ml from the starting inoculum. Both CPA and ERT were bactericidal against all four strains. CPA demonstrated improved activity against Bacteroides strains compared to that of ERT but had similar activity against Finegoldia magna and P. bivia, although modest regrowth was observed with CPA against P. bivia. No resistance emerged from any of the models. The pharmacokinetics achieved were 92 to 105% of the targets. CPA has potent in vitro activity against common anaerobic pathogens at clinically relevant drug exposures and may be a suitable single product for the management of complicated polymicrobial infections.

  15. The absorbed dose to blood from blood-borne activity

    NASA Astrophysics Data System (ADS)

    Hänscheid, H.; Fernández, M.; Lassmann, M.

    2015-01-01

    The radiation absorbed dose to blood and organs from activity in the blood is relevant for nuclear medicine dosimetry and for research in biodosimetry. The present study provides coefficients for the average absorbed dose rates to the blood from blood-borne activity for radionuclides frequently used in targeted radiotherapy and in PET diagnostics. The results were deduced from published data for vessel radius-dependent dose rate coefficients and reasonable assumptions on the blood-volume distribution as a function of the vessel radius. Different parts of the circulatory system were analyzed separately. Vessel size information for heart chambers, aorta, vena cava, pulmonary artery, and capillaries was taken from published results of morphometric measurements. The remaining blood not contained in the mentioned vessels was assumed to reside in fractal-like vascular trees, the smallest branches of which are the arterioles or venules. The applied vessel size distribution is consistent with recommendations of the ICRP on the blood-volume distribution in the human. The resulting average absorbed dose rates to the blood per nuclear disintegration per milliliter (ml) of blood are (in 10-11 Gy·s-1·Bq-1·ml) Y-90: 5.58, I-131: 2.49, Lu-177: 1.72, Sm-153: 2.97, Tc-99m: 0.366, C-11: 4.56, F-18: 3.61, Ga-68: 5.94, I-124: 2.55. Photon radiation contributes 1.1-1.2·10-11 Gy·s-1·Bq-1·ml to the total dose rate for positron emitters but significantly less for the other nuclides. Blood self-absorption of the energy emitted by ß-particles in the whole blood ranges from 37% for Y-90 to 80% for Tc-99m. The correspondent values in vascular trees, which are important for the absorbed dose to organs, range from 30% for Y-90 to 82% for Tc-99m.

  16. A combination of ceftaroline and daptomycin has synergistic and bactericidal activity in vitro against daptomycin nonsusceptible methicillin-resistant Staphylococcus aureus (MRSA).

    PubMed

    Shafiq, Iffat; Bulman, Zackery P; Spitznogle, Sarah L; Osorio, Justin E; Reilly, Irene S; Lesse, Alan J; Parameswaran, Ganapathi I; Mergenhagen, Kari A; Tsuji, Brian T

    2017-05-01

    There is an urgent need to optimize therapeutic options in patients with methicillin-resistant Staphylococcus aureus (MRSA) bacteremia who have failed conventional therapy. Two clinical isolates were obtained from a 68-year-old male with persistent MRSA bacteremia before and after the development of daptomycin nonsusceptibility. The pharmacodynamic activity of monotherapies and combinations of ceftaroline, daptomycin, cefoxitin, nafcillin and vancomycin were evaluated in time-kill experiments versus 10(8) CFU/mL of the pre- and post-daptomycin nonsusceptible MRSA isolates. Cefoxitin, nafcillin and vancomycin alone or in combination with ceftaroline failed to generate prolonged bactericidal activity against the post-daptomycin nonsusceptible isolate whereas a ceftaroline-daptomycin combination resulted in 6, 24 and 48 h log10(CFU/mL) reductions of 3.90, 4.40 and 6.32. Population analysis profiles revealed a daptomycin heteroresistant subpopulation of the pre-daptomycin nonsusceptible MRSA isolate that expanded by >10,000× on daptomycin agar containing 2-16 mg/L in the post-daptomycin nonsusceptible isolate. Daptomycin and ceftaroline combinations may be promising against persistent MRSA bacteremia.

  17. Azithromycin Synergizes with Cationic Antimicrobial Peptides to Exert Bactericidal and Therapeutic Activity Against Highly Multidrug-Resistant Gram-Negative Bacterial Pathogens

    PubMed Central

    Lin, Leo; Nonejuie, Poochit; Munguia, Jason; Hollands, Andrew; Olson, Joshua; Dam, Quang; Kumaraswamy, Monika; Rivera, Heriberto; Corriden, Ross; Rohde, Manfred; Hensler, Mary E.; Burkart, Michael D.; Pogliano, Joe; Sakoulas, George; Nizet, Victor

    2015-01-01

    Antibiotic resistance poses an increasingly grave threat to the public health. Of pressing concern, rapid spread of carbapenem-resistance among multidrug-resistant (MDR) Gram-negative rods (GNR) is associated with few treatment options and high mortality rates. Current antibiotic susceptibility testing guiding patient management is performed in a standardized manner, identifying minimum inhibitory concentrations (MIC) in bacteriologic media, but ignoring host immune factors. Lacking activity in standard MIC testing, azithromycin (AZM), the most commonly prescribed antibiotic in the U.S., is never recommended for MDR GNR infection. Here we report a potent bactericidal action of AZM against MDR carbapenem-resistant isolates of Pseudomonas aeruginosa, Klebsiella pneumoniae, and Acinetobacter baumannii. This pharmaceutical activity is associated with enhanced AZM cell penetration in eukaryotic tissue culture media and striking multi-log-fold synergies with host cathelicidin antimicrobial peptide LL-37 or the last line antibiotic colistin. Finally, AZM monotherapy exerts clear therapeutic effects in murine models of MDR GNR infection. Our results suggest that AZM, currently ignored as a treatment option, could benefit patients with MDR GNR infections, especially in combination with colistin. PMID:26288841

  18. Preparation of bio-deep eutectic solvent triggered cephalopod shaped silver chloride-DNA hybrid material having antibacterial and bactericidal activity.

    PubMed

    Bhatt, Jitkumar; Mondal, Dibyendu; Bhojani, Gopal; Chatterjee, Shruti; Prasad, Kamalesh

    2015-11-01

    2.5% w/w DNA (Salmon testes) was solubilized in a bio-deep eutectic solvent [(bio-DES), obtained by the complexation of choline chloride and ethylene glycol at 1:2 molar ratio] containing 1% w/w of silver chloride (AgCl) to yield a AgCl decorated DNA based hybrid material. Concentration dependent formation of AgCl crystals in the DES was observed and upon interaction with DNA it gave formation of a cephalopod shaped hybrid material. DNA was found to maintain its chemical and structural stability in the material. Further, AgCl microstructures were found to have orderly self assembled on the DNA helices indicating the electrostatic interaction between Ag(+) and phosphate side chain of DNA as a driving force for the formation of the material with ordered microstructural distribution of AgCl. Furthermore, the functionalized material exhibited excellent antibacterial and bactericidal activity against both Gram negative and Gram positive pathogenic bacteria.

  19. Facile synthesis of gold nanoparticles on propylamine functionalized SBA-15 and effect of surface functionality of its enhanced bactericidal activity against gram positive bacteria

    NASA Astrophysics Data System (ADS)

    Bhuyan, Diganta; Gogoi, Animesh; Saikia, Mrinal; Saikia, Ratul; Saikia, Lakshi

    2015-07-01

    The facile synthesis of an SBA-15-pr-+NH3.Au0 nano-hybrid material by spontaneous autoreduction of aqueous chloroaurate anions on propylamine functionalized SBA-15 was successfully demonstrated. The as-synthesized SBA-15-pr-+NH3.Au0 nano-hybrid material was well characterized using low and wide angle x-ray diffraction (XRD), N2 adsorption-desorption isotherms, Fourier transform infrared (FTIR), transmission electron microscopy (TEM), scanning electron microscopy-energy dispersive x-ray spectroscopy (SEM-EDX), x-ray photoelectron spectroscopy (XPS), UV-Visible spectroscopy and atomic absorption spectroscopy (AAS). The activity of the nano-hybrid material as a potent bactericidal agent was successfully tested against Gram positive/negative bacteria viz. Bacillus subtilis, Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa. The colony killing percentage of Gram positive bacteria was found to be higher than Gram negative bacteria due to the stronger electrostatic interaction between the positively-charged amine functionality of SBA-15 and the negatively charged functionality of the bacterial cell wall.

  20. Stem bark extract and fraction of Persea americana (Mill.) exhibits bactericidal activities against strains of bacillus cereus associated with food poisoning.

    PubMed

    Akinpelu, David A; Aiyegoro, Olayinka A; Akinpelu, Oluseun F; Okoh, Anthony I

    2014-12-30

    The study investigates the in vitro antibacterial potentials of stem bark extracts of Persea americana on strains of Bacillus cereus implicated in food poisoning. The crude stem bark extracts and butanolic fraction at a concentration of 25 mg/mL and 10 mg/mL, respectively, exhibited antibacterial activities against test isolates. The zones of inhibition exhibited by the crude extract and the fraction ranged between 10 mm and 26 mm, while the minimum inhibitory concentration values ranged between 0.78 and 5.00 mg/mL. The minimum bactericidal concentrations ranged between 3.12 mg/mL-12.5 mg/mL and 1.25-10 mg/mL for the extract and the fraction, respectively. The butanolic fraction killed 91.49% of the test isolates at a concentration of 2× MIC after 60 min of contact time, while a 100% killing was achieved after the test bacterial cells were exposed to the butanolic fraction at a concentration of 3× MIC after 90 min contact time. Intracellular protein and potassium ion leaked out of the test bacterial cells when exposed to certain concentrations of the fraction; this is an indication of bacterial cell wall disruptions by the extract's butanolic fraction and, thus, caused a biocidal effect on the cells, as evident in the killing rate test results.

  1. Eco-friendly synthesis of silver and gold nanoparticles with enhanced bactericidal activity and study of silver catalyzed reduction of 4-nitrophenol.

    PubMed

    Naraginti, Saraschandra; Sivakumar, A

    2014-07-15

    The present study reports a simple and robust method for synthesis of silver and gold nanoparticles using Coleus forskohlii root extract as reducing and stabilizing agent. Stable silver nanoparticles (AgNPs) and gold nanopoarticles (AuNPs) were formed on treatment of an aqueous silver nitrate (AgNO3) and chloroauric acid (HAuCl4) solutions with the root extract. The nanoparticles obtained were characterized by UV-Visible spectroscopy, Transmission electron microscopy (TEM), X-ray diffraction (XRD) and Fourier-transform infrared spectroscopy (FT-IR). UV-Vis and TEM analysis indicate that with higher quantities of root extract, the interaction is enhanced leading to size reduction of spherical metal nanoparticles. XRD confirms face-centered cubic phase and the diffraction peaks can be attributed to (111), (200), (222) and (311) planes for these nanoparticles. These synthesized Ag and Au nanoparticles were found to exhibit excellent bactericidal activity against clinically isolated selected pathogens such as Escherichia coli (E. coli), Pseudomonas aeruginosa (P. aeruginosa) and Staphylococcus aureus (S. aureus). The synthesized AgNPs were also found to function as an efficient green catalyst in the reduction of anthropogenic pollutant 4-nitrophenol (4-NP) to 4-aminophenol (4-AP) by sodium borohydride, which was apparent from the periodical color change from bright yellow to colorless, after the addition of AgNPs.

  2. In vitro and in vivo bactericidal activities of vancomycin dispersed in porous biodegradable poly(epsilon-caprolactone) microparticles.

    PubMed

    Le Ray, Anne-Marie; Gautier, Hélène; Laty, Marie-Katel; Daculsi, Guy; Merle, Christian; Jacqueline, Cédric; Hamel, Antoine; Caillon, Jocelyne

    2005-07-01

    Treatment of methicillin-resistant Staphylococcus aureus osteomyelitis requires a prolonged antibiotic therapy with vancomycin. Because of its weak diffusion, the in situ implantation of vancomycin could be interesting. The activity of vancomycin encapsulated in microparticles was evaluated in vitro and in vivo on rabbit osteomyelitis and showed a good activity compared to intravenous administration.

  3. GREATER HEMOCYTE BACTERICIDAL ACTIVITY IN OYSTERS (CRASSOSTREA VIRGINICA) FROM A RELATIVELY CONTAMINATED SITE IN PENSACOLA BAY, FLORIDA.

    EPA Science Inventory

    Bivalve mollusks such as Crassostrea virginica inhabiting polluted estuaries and coastal areas may bioaccumulate high concentrations of contaminants without apparent ill effects. However, changes in putative internal defense activities have been associated with contaminant accumu...

  4. The Role of Cytokines in the Functional Activity of Phagocytes in Blood and Colostrum of Diabetic Mothers

    PubMed Central

    Fagundes, Danny Laura Gomes; França, Eduardo Luzía; Morceli, Glilciane; Rudge, Marilza Vieira Cunha; Calderon, Iracema de Mattos Paranhos; Honorio-França, Adenilda Cristina

    2013-01-01

    Immune response changes induced by diabetes are a risk factor for infections during pregnancy and may modify the development of the newborn's immune system. The present study analyzed colostrum and maternal and cord blood of diabetic women to determine (1) the levels of the cytokines IFN-γ and TGF-β and (2) phagocytic activity after incubation with cytokines. Methods. Colostrum and maternal and cord blood samples were classified into normoglycemic (N = 20) and diabetic (N = 19) groups. Cytokine levels, superoxide release, rate of phagocytosis, bactericidal activity, and intracellular Ca2+ release by phagocytes were analyzed in the samples. Irrespective of glycemic status, IFN-γ and TGF-β levels were not changed in colostrum and maternal and cord blood. In maternal blood and colostrum, superoxide release by cytokine-stimulated phagocytes was similar between the groups. Compared to spontaneous release, superoxide release was stimulated by IFN-γ and TGF-β in normoglycemic and diabetic groups. In the diabetic group, cord blood phagocytes incubated with IFN-γ exhibited higher phagocytic activity in response to EPEC, and maternal blood exhibited lower microbicidal activity. These data suggest that diabetes interferes in maternal immunological parameters and that IFN-γ and TGF-β modulate the functional activity of phagocytes in the colostrum, maternal blood, and cord blood of pregnant diabetic women. PMID:24489577

  5. Removal of radioisotopes in solution and bactericidal/bacteriostatic sterilising power in activated carbon and metal silver filters.

    PubMed

    Maioli, Claudio; Bestetti, Alberto; Mauri, Alessandro; Pozzato, Carlo; Paroni, Rita

    2009-01-01

    Activated carbon filters play an important role in water filtration and purification from contaminants of different origin. Their limit consists in bacterial proliferation, which may occur only during prolonged periods of non-use and in their ability to remove radioactive contaminants present in waste water from Industry or Nuclear Medicine departments. In this work we tested a commercially available activated carbon filter for water purification enriched with silver plated parts incubating in static condition at room temperature different micro organisms (Enterococcus faecalis, Escherichia coli, Pseudomonas aeruginosa, Salmonella enteritidis, Staphylococcus aureus, Aspergillum niger), up to 78 days. The microbial growth was in general more inhibited in the presence of metal silver into the activated carbon in respect to filters with the activated carbon alone: >4log inhibition of bacterial proliferation after 78 days of incubation the presence of silver vs. 2log without silver. When the filters were incubated empty of carbon, the sterilizing power of silver was confirmed further. The activated carbon filters proved also their ability in removing from water the principal radioisotopes used for residues liquid medical and research purposes ((131)I, (99m)Tc, (201)Tl, (67)Ga). These results contribute useful data for the use of the silver-enriched carbon filters in water filtration both for daily use at home, and professional use in a Nuclear Medicine laboratory.

  6. Colloidal titania-silica-iron oxide nanocomposites and the effect from silica thickness on the photocatalytic and bactericidal activities

    NASA Astrophysics Data System (ADS)

    Chanhom, Padtaraporn; Charoenlap, Nisanart; Tomapatanaget, Boosayarat; Insin, Numpon

    2017-04-01

    New types of colloidal multifunctional nanocomposites that combine superparamagnetic character and high photocatalytic activity were synthesized and investigated. The superparamagnetic nanocomposites composed of anatase titania, silica, and iron oxide nanoparticles (TSI) were synthesized using thermal decomposition method followed by microemulsion method, without calcination at high temperature. Different techniques including X-ray diffraction (XRD) and transmission electron microscope (TEM) were used to characterize and confirm the structure of the nanocomposites. These nanocomposites showed high photocatalytic activity when used in the photodegradation of methylene blue under irradiation with a black light lamp. Moreover, the nanocomposites exhibited high antibacterial properties. From our study, the nanocomposites can be useful in various applications such as removal of pollutants with readily separation from the environment using an external magnetic field. These composites could effectively photo-degrade the dye at least three cycles without regeneration. The effects of silica shell thickness on the photocatalytic activity was investigated, and the thickness of 6 nm of the silica interlayer is enough for the inhibition of electron translocation between titania and iron oxide nanoparticles and maintaining the efficiency of photocatalytic activity of titania nanoparticles.

  7. Bactericidal activity of the food color additive Phloxine B against Staphylococcus aureus and other food borne microbial pathogens

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The spread of antibiotic resistance among Staphylococcus aureus strains requires the development of new anti S. aureus agents. The objective of this study was evaluating the antimicrobial activity of the food color additive Phloxine B against S. aureus and other food microbial pathogens. Our result ...

  8. Influence of ethylenediamine-n,n’-disuccinic acid (EDDS) concentration on the bactericidal activity of fatty acids in vitro

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The antibacterial activity of mixtures of ethylenediamine-N,N’-disuccinic acid (EDDS) and antibacterial fatty acids (FA) was examined using the agar diffusion assay. Solutions of caproic, caprylic, capric, and lauric acids dissolved in potassium hydroxide (KOH) were supplemented with 0, 5, or 10 mM ...

  9. Physicochemical properties of bactericidal plasma-treated water

    NASA Astrophysics Data System (ADS)

    Ikawa, Satoshi; Tani, Atsushi; Nakashima, Yoichi; Kitano, Katsuhisa

    2016-10-01

    Plasma-treated water (PTW), i.e. distilled water (DW) exposed to low-temperature atmospheric pressure helium plasma, exhibited strong bactericidal activity against Escherichia coli in suspension even within a few minutes of preparation. This effect was enhanced under acidic conditions. The bactericidal activity of PTW was attenuated according to first-order kinetics and the half-life was highly temperature dependent. The electron spin resonance (ESR) signal of an adduct of the superoxide anion radical (\\text{O}2-\\bullet ) was detected in an aqueous solution using a spin-trapping reagent mixed with PTW, and adding superoxide dismutase to the PTW resulted in a loss of the bactericidal activity and weakening of the ESR adduct signal of \\text{O}2-\\bullet in the spin-trapping. These results suggest that \\text{O}2-\\bullet plays an important role in imparting bactericidal activity to PTW. Moreover, molecular nitrogen was required both in the ambient gas and in the DW used to prepare the PTW. We, therefore, suggest that the reactive molecule in PTW with bactericidal effects is not a free reactive oxygen species but nitrogen atom(s)-containing molecules that release \\text{O}2-\\bullet , such as peroxynitrous acid (ONOOH) or peroxynitric acid (O2NOOH). Considering the activation energy for degradation of these species, we conclude that peroxynitric acid stored in PTW induces the bactericidal effect.

  10. BACTERICIDAL SUBSTANCE FROM STAPHYLOCOCCUS AUREUS

    PubMed Central

    Dajani, Adnan S.; Gray, Ernest D.; Wannamaker, Lewis W.

    1970-01-01

    A bactericidal substance previously isolated from phage type 71 Slaphylococcus aureus has been further identified and characterized. Staphylococci belonging to phage type 71 produce the substance in higher titers than staphylococci lysed by other phages in group II in addition to phage 71. Other staphylococci do not produce the bactericidal substance. The bactericidal substance shares several of the properties of bacteriocins but differs from this group of antibiotic substances in some respects. A combination of ammonium sulfate fractionation and gel filtration on a Sephadex G-100 column resulted in considerable degree of purification of the bactericidal substance. The substance is a previously unrecognized product of S. aureus and is distinct from other extracellular products of this organism. PMID:5443199

  11. Activation states of blood eosinophils in asthma.

    PubMed

    Johansson, M W

    2014-04-01

    Asthma is characterized by airway inflammation rich in eosinophils. Airway eosinophilia is associated with exacerbations and has been suggested to play a role in airway remodelling. Recruitment of eosinophils from the circulation requires that blood eosinophils become activated, leading to their arrest on the endothelium and extravasation. Circulating eosinophils can be envisioned as potentially being in different activation states, including non-activated, pre-activated or 'primed', or fully activated. In addition, the circulation can potentially be deficient of pre-activated or activated eosinophils, because such cells have marginated on activated endothelium or extravasated into the tissue. A number of eosinophil surface proteins, including CD69, L-selectin, intercellular adhesion molecule-1 (ICAM-1, CD54), CD44, P-selectin glycoprotein ligand-1 (PSGL-1, CD162), cytokine receptors, Fc receptors, integrins including αM integrin (CD11b), and activated conformations of Fc receptors and integrins, have been proposed to report cell activation. Variation in eosinophil activation states may be associated with asthma activity. Eosinophil surface proteins proposed to be activation markers, with a particular focus on integrins, and evidence for associations between activation states of blood eosinophils and features of asthma are reviewed here. Partial activation of β1 and β2 integrins on blood eosinophils, reported by monoclonal antibodies (mAbs) N29 and KIM-127, is associated with impaired pulmonary function and airway eosinophilia, respectively, in non-severe asthma. The association with lung function does not occur in severe asthma, presumably due to greater eosinophil extravasation, specifically of activated or pre-activated cells, in severe disease.

  12. Visible light induced bactericidal and photocatalytic activity of hydrothermally synthesized BiVO4 nano-octahedrals.

    PubMed

    Sharma, Rishabh; Uma; Singh, Sonal; Verma, Ajit; Khanuja, Manika

    2016-09-01

    In the present work, monoclinic bismuth vanadate (m-BiVO4) nanostructures have been synthesized via simple hydrothermal method and employed for visible light driven antimicrobial and photocatalytic activity. Morphology (octahedral) and size (200-300nm) of the m-BiVO4 are studied using transmission electron microscopy (TEM). The crystal structure of m-BiVO4 (monoclinic scheelite structure) is confirmed by high resolution-TEM (HRTEM) and X-ray diffraction (XRD) studies. The band gap of m-BiVO4 was estimated to be ca. 2.42eV through Kubelka-Munk function F(R∞) using diffuse reflectance spectroscopy (DRS). Antimicrobial action of m-BiVO4 is anticipated by (i) shake flask method, (ii) MTT [3-(4,5-Dimethylthiazol-2-Yl)-2,5-Diphenyltetrazolium Bromide] assay for cytotoxicity. SEM analysis has been carried on Escherichia coli (E.coli) before and after treatment with nanostructure materials to reveal the mechanism underlying the antimicrobial action. Antimicrobial activity is studied as a function of m-BiVO4 concentration viz. 20, 40, 60 and 80ppm. The bacterial growth is decreased 80% to 96%, with the increase in m-BiVO4 concentration from 20ppm to 80ppm, respectively, in 2h. Photocatalytic activity and rate kinetics of m-BiVO4 nanostructures have been studied as a function of time on methylene blue (MB) dye degradation which is one of the waste products of textile industries and responsible for water pollution.

  13. Bordetella parapertussis Circumvents Neutrophil Extracellular Bactericidal Mechanisms

    PubMed Central

    Gorgojo, Juan; Scharrig, Emilia; Gómez, Ricardo M.; Harvill, Eric T.; Rodríguez, Maria Eugenia

    2017-01-01

    B. parapertussis is a whooping cough etiological agent with the ability to evade the immune response induced by pertussis vaccines. We previously demonstrated that in the absence of opsonic antibodies B. parapertussis hampers phagocytosis by neutrophils and macrophages and, when phagocytosed, blocks intracellular killing by interfering with phagolysosomal fusion. But neutrophils can kill and/or immobilize extracellular bacteria through non-phagocytic mechanisms such as degranulation and neutrophil extracellular traps (NETs). In this study we demonstrated that B. parapertussis also has the ability to circumvent these two neutrophil extracellular bactericidal activities. The lack of neutrophil degranulation was found dependent on the O antigen that targets the bacteria to cell lipid rafts, eventually avoiding the fusion of nascent phagosomes with specific and azurophilic granules. IgG opsonization overcame this inhibition of neutrophil degranulation. We further observed that B. parapertussis did not induce NETs release in resting neutrophils and inhibited NETs formation in response to phorbol myristate acetate (PMA) stimulation by a mechanism dependent on adenylate cyclase toxin (CyaA)-mediated inhibition of reactive oxygen species (ROS) generation. Thus, B. parapertussis modulates neutrophil bactericidal activity through two different mechanisms, one related to the lack of proper NETs-inducer stimuli and the other one related to an active inhibitory mechanism. Together with previous results these data suggest that B. parapertussis has the ability to subvert the main neutrophil bactericidal functions, inhibiting efficient clearance in non-immune hosts. PMID:28095485

  14. Contact activation of blood-plasma coagulation.

    PubMed

    Vogler, Erwin A; Siedlecki, Christopher A

    2009-04-01

    This opinion identifies inconsistencies in the generally-accepted surface biophysics involved in contact activation of blood-plasma coagulation, reviews recent experimental work aimed at resolving inconsistencies, and concludes that this standard paradigm requires substantial revision to accommodate new experimental observations. Foremost among these new findings is that surface-catalyzed conversion of the blood zymogen factor XII (FXII, Hageman factor) to the enzyme FXIIa (FXII [surface] --> FXIIa, a.k.a. autoactivation) is not specific for anionic surfaces, as proposed by the standard paradigm. Furthermore, it is found that surface activation is moderated by the protein composition of the fluid phase in which FXII autoactivation occurs by what appears to be a protein-adsorption-competition effect. Both of these findings argue against the standard view that contact activation of plasma coagulation is potentiated by the assembly of activation-complex proteins (FXII, FXI, prekallikrein, and high-molecular weight kininogen) directly onto activating surfaces (procoagulants) through specific protein/surface interactions. These new findings supplement the observation that adsorption behavior of FXII and FXIIa is not remarkably different from a wide variety of other blood proteins surveyed. Similarity in adsorption properties further undermines the idea that FXII and/or FXIIa are distinguished from other blood proteins by unusual adsorption properties resulting in chemically-specific interactions with activating anionic surfaces. IMPACT STATEMENT: This review shows that the consensus biochemical mechanism of contact activation of blood-plasma coagulation that has long served as a rationale for poor hemocompatibility is an inadequate basis for surface engineering of advanced cardiovascular biomaterials.

  15. The promiscuous and synergic molecular interaction of polyphenols in bactericidal activity: an opportunity to improve the performance of antibiotics?

    PubMed

    Tomás-Menor, Laura; Barrajón-Catalán, Enrique; Segura-Carretero, Antonio; Martí, Nuria; Saura, Domingo; Menéndez, Javier A; Joven, Jorge; Micol, Vicente

    2015-03-01

    Plant polyphenols are a potential source of new antimicrobial molecules against bacteria because most newly developed antimicrobial agents do not improve the clinical management of infectious diseases. The potential synergism between the major polyphenolic compounds present in a Cistus salviifolius extract, which was characterized by HPLC-ESI-MS/MS, was investigated by the isobole method and the fractional inhibitory concentration index determination. Pairwise combinations of selected flavonoids and ellagitannins present in C. salviifolius extract were assayed against the in vitro growth of Staphylococcus aureus. Some combinations revealed synergic effects, resulting in a reduction of the minimum inhibitory concentration required to inhibit 50% growth (MIC50 ) up to 20 times lower as compared with the individual compounds. Some of the combinations exhibited MIC50 values close to drug potency level (0.5-1 µg/mL). Punicalagin and myricetin were the major contributors in the combinations. The proportion between the compounds in the synergic mixtures is crucial and may explain the superior antimicrobial activity displayed by this extract when compared with other botanical extracts. The rational optimization of these combinations could lead to the design of potent antimicrobial phytopharmaceuticals, which may improve the performance of current antibiotics, taking advantage of the multi-targeted and synergic molecular interactions of selected polyphenols.

  16. Cinnamon zeylanicum bark extract and powder mediated green synthesis of nano-crystalline silver particles and its bactericidal activity.

    PubMed

    Sathishkumar, M; Sneha, K; Won, S W; Cho, C-W; Kim, S; Yun, Y-S

    2009-10-15

    The exploitation of various plant materials for the biosynthesis of nanoparticles is considered a green technology as it does not involve any harmful chemicals. The present study reports the synthesis of silver (Ag) nanoparticles from silver precursor using the bark extract and powder of novel Cinnamon zeylanicum. Water-soluble organics present in the plant materials were mainly responsible for the reduction of silver ions to nano-sized Ag particles. TEM and XRD results confirmed the presence of nano-crystalline Ag particles. The pH played a major role in size control of the particles. Bark extract produced more Ag nanoparticles than the powder did, which was attributed to the large availability of the reducing agents in the extract. Zeta potential studies showed that the surface charge of the formed nanoparticles was highly negative. The EC(50) value of the synthesized nanoparticles against Escherichia coli BL-21 strain was 11+/-1.72 mg/L. Thus C. zeylanicum bark extract and powder are a good bio-resource/biomaterial for the synthesis of Ag nanoparticles with antimicrobial activity.

  17. Extracellular synthesis of silver nanoparticles by novel Pseudomonas veronii AS41G inhabiting Annona squamosa L. and their bactericidal activity

    NASA Astrophysics Data System (ADS)

    Baker, Syed; Mohan Kumar, K.; Santosh, P.; Rakshith, D.; Satish, S.

    2015-02-01

    In present investigation extracellular synthesis of silver nanoparticles were synthesized using cell free supernatant of Pseudomonas veronii AS41G isolated from Annona squamosa L. The bacterium significantly reduced silver nitrate to generate silver nanoparticles which was characterized with hyphenated techniques. Synthesis of silver nanoparticles preliminary confirmed by UV-Visible spectrophotometry with the intense peak at 410 nm, Further FTIR analysis revealed the possible role of biomolecules in the supernatant responsible for mediating the nanoparticles formation. The XRD spectra exhibited the characteristic Bragg peaks of 1 0 0, 1 1 1, 2 0 0, and 2 2 0 facets of the face centred cubic symmetry of nanoparticles suggesting that these nanoparticles were crystalline in nature. TEM microgram showed polydispersity of nanoparticles with size ranging from 5 to 50 nm. Synthesized silver nanoparticles showed antibacterial activity against human and environmental pathogens including MRSA. The study enlightens the role of biosynthesized silver nanoparticles as an emerging alternative for drug resistant microorganisms. The obtained results are promising enough to pave the environmentally benign nanoparticle synthesis processes without use of any toxic chemicals and also envision the emerging role of endophytes towards synthesis of nanoparticles. With scanty reports available on P.veronii species, a new role has been reported in this study which will be very valuable for future researchers working on it.

  18. Greater hemocyte bactericidal activity in oysters (Crassostrea virginica) from a relatively contaminated site in Pensacola Bay, Florida.

    PubMed

    Oliver, Leah M; Fisher, William S; Volety, Aswani K; Malaeb, Ziad

    2003-09-10

    Bivalve mollusks such as Crassostrea virginica inhabiting polluted estuaries and coastal areas may bioaccumulate high concentrations of contaminants without apparent ill effects. However, changes in putative internal defense activities have been associated with contaminant accumulation in both experimental and long-term field exposures. In an effort to elucidate these relationships, 40 oysters were collected from Bayou Chico (BC) and East Bay (EB) in Pensacola Bay, FL, two estuaries known to differ in the type and magnitude of chemical contaminants present. Oyster tissue concentrations of metals, tri- and dibutyltin (TBT, DBT), polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs) were measured in individual oysters, as were hemocyte counts (HCs), hemocyte bacterial killing indices (KI), serum lysozyme (LYS) and serum protein (PRO) levels. Average HC, KI, LYS and PRO were significantly higher in BC oysters, which also had significantly higher tissue concentrations of total trace metals, butyltins (BTs), PAHs, PCBs, pesticides, and Mn, Cu, Zn and Sn. EB oysters had low organic contaminant levels and no detectable BTs, but significantly higher concentrations of Al, Cr, Fe, Ag, Cd, and Hg. Simple correlation analysis between specific defense measurements and specific chemical analytes showed specific positive relationships that corroborated previous findings in other FL estuaries. Canonical correlation analysis was used to examine relationships between defense measurements and tissue metals using linearly combined sets of variables. Results were also consistent with previous findings-the highest possible canonical correlation was positive: r=0.864, P<0.0019 among canonical variables composed of HC, KI and LYS for defense, and Fe, Cu, Ag, Cd, Sb, Sn, Ni, Pb and Hg for metals.

  19. Shape-dependent bactericidal activity of TiO2 for the killing of Gram-negative bacteria Agrobacterium tumefaciens under UV torch irradiation.

    PubMed

    Aminedi, Raghavendra; Wadhwa, Gunveen; Das, Niranjan; Pal, Bonamali

    2013-09-01

    This paper demonstrated the relative bactericidal activity of photoirradiated (6W-UV Torch, λ > 340 nm and intensity = 0.64 mW/cm(2)) P25-TiO2 nanoparticles, nanorods, and nanotubes for the killing of Gram-negative bacterium Agrobacterium tumefaciens LBA4404 for the first time. TiO2 nanorod (anatase) with length of 70-100 nm and diameter of 10-12 nm, and TiO2 nanotube with length of 90-110 nm and diameter of 9-11 nm were prepared from P-25 Degussa TiO2 (size, 30-50 nm) by hydrothermal method and compared their biocidal activity both in aqueous slurry and thin films. The mode of bacterial cell decomposition was analyzed through transmission electron microscopy (TEM), Fourier transform-infrared (FT-IR), and K(+) ion leakage. The antimicrobial activity of photoirradiated TiO2 of different shapes was found to be in the order P25-TiO2 > nanorod > nanotube which is reverse to their specific surface area as 54 < 79 < 176 m(2) g(-1), evidencing that the highest activity of P25-TiO2 nanoparticles is not due to surface area as their crystal structure and surface morphology are entirely different. TiO2 thin films always exhibited less photoactivity as compared to its aqueous suspension under similar conditions of cell viability test. The changes in the bacterial surface morphology by UV-irradiated P25-TiO2 nanoparticles was examined by TEM, oxidative degradation of cell components such as proteins, carbohydrates, phospholipids, nucleic acids by FT-IR spectral analysis, and K(+) ion leakage (2.5 ppm as compared to 0.4 ppm for control culture) as a measure of loss in cell membrane permeability.

  20. Preliminary flight prototype potable water bactericide system

    NASA Technical Reports Server (NTRS)

    Jasionowski, W. J.; Allen, E. T.

    1973-01-01

    The development, design, and testing of a preliminary flight prototype potable water bactericide system are described. The system is an assembly of upgraded canisters composed of: (1) A biological filter; (2) an activated charcoal and ion exchange resin canister; (3) a silver chloride canister, (4) a deionizer, (5) a silver bromide canister with a partial bypass, and (6) mock-up instrumentation and circuitry. The system exhibited bactericidal activity against 10 to the 9th power Pseudomonas aeruginosa and/or Type IIIa, and reduced Bacillus subtilis by up to 5 orders of magnitude in 24 hours at ambient temperatures with a 1 ppm silver ion dose. Four efficacy tests were performed with a AgBr canister dosing anticipated fuel cell water. Tests show that a 0.05 ppm silver ion dose was bactericidal against 3 plus or minus 1 x 10 to the 9th power (5 plus or minus 1 x 10,000/ml Pseudomonas aeruginosa and/or Type IIIa in 15 minutes or less.

  1. Contact activation of blood-plasma coagulation

    NASA Astrophysics Data System (ADS)

    Golas, Avantika

    Surface engineering of biomaterials with improved hemocompatibility is an imperative, given the widespread global need for cardiovascular devices. Research summarized in this dissertation focuses on contact activation of FXII in buffer and blood plasma frequently referred to as autoactivation. The extant theory of contact activation imparts FXII autoactivation ability to negatively charged, hydrophilic surfaces. According to this theory, contact activation of plasma involves assembly of proteins comprising an "activation complex" on activating surfaces mediated by specific chemical interactions between complex proteins and the surface. This work has made key discoveries that significantly improve our core understanding of contact activation and unravel the existing paradigm of plasma coagulation. It is shown herein that contact activation of blood factor XII (FXII, Hageman factor) in neat-buffer solution exhibits a parabolic profile when scaled as a function of silanized-glass-particle activator surface energy (measured as advancing water adhesion tension t°a=g° Iv costheta in dyne/cm, where g°Iv is water interfacial tension in dyne/cm and theta is the advancing contact angle). Nearly equal activation is observed at the extremes of activator water-wetting properties --36 < t°a < 72 dyne/cm (O° ≤ theta < 120°), falling sharply through a broad minimum within the 20 < t°a < 40 dyne/cm (55° < theta < 75°). Furthermore, contact activation of FXII in buffer solution produces an ensemble of protein fragments exhibiting either procoagulant properties in plasma (proteolysis of blood factor XI or prekallikrein), amidolytic properties (cleavage of s-2302 chromogen), or the ability to suppress autoactivation through currently unknown biochemistry. The relative proportions of these fragments depend on activator surface chemistry/energy. We have also discovered that contact activation is moderated by adsorption of plasma proteins unrelated to coagulation through an

  2. Utilization of time-kill kinetic methodologies for assessing the bactericidal activities of ampicillin and bismuth, alone and in combination, against Helicobacter pylori in stationary and logarithmic growth phases.

    PubMed Central

    Coudron, P E; Stratton, C W

    1995-01-01

    Assessment of in vitro susceptibility testing of Helicobacter pylori is difficult because of the fastidious, slowly growing nature of this microorganism. The high rate of relapse observed clinically and a possible subpopulation of cells that are not actively replicating suggest the potential need for bactericidal therapy in order to eradicate H. pylori. We used modified time-kill kinetic methodology in order to evaluate the bactericidal activities of ampicillin and bismuth, alone and in combination, against three strains of H. pylori in both a stationary (slow) growth phase and a logarithmic (rapid) growth phase. We found that ampicillin produced a decrease in CFU per milliliter (2 to 4 log10 units) for three strains of H. pylori when tested in logarithmic growth phases but was less inhibitory (< 1-log10-unit decrease in CFU per milliliter) when tested in a stationary growth phase. In contrast, bismuth, when tested in a logarithmic growth phase, produced little inhibitory effect, as the CFU for all strains tested increased above the inoculum. However, when tested in a stationary growth phase, bismuth produced a decrease in CFU per milliliter of < 1 to > 3 log10 units). The activities of these two agents when combined mimicked the activity of the most active drug alone for that growth phase. We conclude that the clinical use of ampicillin combined with bismuth has been more effective than that of either agent used alone because ampicillin targets replicating cells, whereas bismuth targets cells that are not actively replicating. PMID:7695331

  3. Migration Inhibitory Factor and Macrophage Bactericidal Function

    PubMed Central

    Simon, Harvey B.; Sheagren, John N.

    1972-01-01

    A homogeneous population of immunologically active lymphocytes was obtained from peritoneal exudates of guinea pigs with delayed hypersensitivity to bovine gamma globulin (BGG). The lymphocytes were cultured with and without BGG for 24 hr, and cell-free supernatant fluids were then assayed simultaneously for their ability to influence two in vitro parameters of macrophage function: migration from capillary tubes and bactericidal capacity. In four consecutive experiments, supernatants from antigenically stimulated lymphocytes exhibited substantial migration-inhibitory-factor activity without enhancing the ability of macrophages to kill Listeria monocytogenes. Lymphocyte lysates were inactive in both assays. Possible mechanisms of lymphocyte-macrophage interactions are discussed. PMID:4120244

  4. Bactericidal antibody response to Pseudomonas aeruginosa by adults with urinary tract infections.

    PubMed Central

    Smalley, D L; Ourth, D D

    1979-01-01

    In this investigation we found that adults with upper urinary tract infections caused by Pseudomonas aeruginosa produced serum antibodies with bactericidal activity against the bacterium. Seventeen of 20 infected adults showed bactericidal activity with a titer range of 1:10 to 1:10,000. PMID:117024

  5. Antagonism between Bacteriostatic and Bactericidal Antibiotics Is Prevalent

    PubMed Central

    Lázár, Viktória; Papp, Balázs; Arnoldini, Markus; Abel zur Wiesch, Pia; Busa-Fekete, Róbert; Fekete, Gergely; Pál, Csaba; Ackermann, Martin; Bonhoeffer, Sebastian

    2014-01-01

    Combination therapy is rarely used to counter the evolution of resistance in bacterial infections. Expansion of the use of combination therapy requires knowledge of how drugs interact at inhibitory concentrations. More than 50 years ago, it was noted that, if bactericidal drugs are most potent with actively dividing cells, then the inhibition of growth induced by a bacteriostatic drug should result in an overall reduction of efficacy when the drug is used in combination with a bactericidal drug. Our goal here was to investigate this hypothesis systematically. We first constructed time-kill curves using five different antibiotics at clinically relevant concentrations, and we observed antagonism between bactericidal and bacteriostatic drugs. We extended our investigation by performing a screen of pairwise combinations of 21 different antibiotics at subinhibitory concentrations, and we found that strong antagonistic interactions were enriched significantly among combinations of bacteriostatic and bactericidal drugs. Finally, since our hypothesis relies on phenotypic effects produced by different drug classes, we recreated these experiments in a microfluidic device and performed time-lapse microscopy to directly observe and quantify the growth and division of individual cells with controlled antibiotic concentrations. While our single-cell observations supported the antagonism between bacteriostatic and bactericidal drugs, they revealed an unexpected variety of cellular responses to antagonistic drug combinations, suggesting that multiple mechanisms underlie the interactions. PMID:24867991

  6. Quantifying of bactericide properties of medicinal plants

    PubMed Central

    Ács, András; Gölöncsér, Flóra; Barabás, Anikó

    2011-01-01

    Extended research has been carried out to clarify the ecological role of plant secondary metabolites (SMs). Although their primary ecological function is self-defense, bioactive compounds have long been used in alternative medicine or in biological control of pests. Several members of the family Labiatae are known to have strong antimicrobial capacity. For testing and quantifying antibacterial activity, most often standard microbial protocols are used, assessing inhibitory activity on a selected strain. In this study, the applicability of a microbial ecotoxtest was evaluated to quantify the aggregate bactericide capacity of Labiatae species, based on the bioluminescence inhibition of the bacterium Vibrio fischeri. Striking differences were found amongst herbs, reaching even 10-fold toxicity. Glechoma hederacea L. proved to be the most toxic, with the EC50 of 0.4073 g dried plant/l. LC50 values generated by the standard bioassay seem to be a good indicator of the bactericide property of herbs. Traditional use of the selected herbs shows a good correlation with bioactivity expressed as bioluminescence inhibition, leading to the conclusion that the Vibrio fischeri bioassay can be a good indicator of the overall antibacterial capacity of herbs, at least on a screening level. PMID:21502819

  7. Cerebral blood flow response to functional activation

    PubMed Central

    Paulson, Olaf B; Hasselbalch, Steen G; Rostrup, Egill; Knudsen, Gitte Moos; Pelligrino, Dale

    2010-01-01

    Cerebral blood flow (CBF) and cerebral metabolic rate are normally coupled, that is an increase in metabolic demand will lead to an increase in flow. However, during functional activation, CBF and glucose metabolism remain coupled as they increase in proportion, whereas oxygen metabolism only increases to a minor degree—the so-called uncoupling of CBF and oxidative metabolism. Several studies have dealt with these issues, and theories have been forwarded regarding the underlying mechanisms. Some reports have speculated about the existence of a potentially deficient oxygen supply to the tissue most distant from the capillaries, whereas other studies point to a shift toward a higher degree of non-oxidative glucose consumption during activation. In this review, we argue that the key mechanism responsible for the regional CBF (rCBF) increase during functional activation is a tight coupling between rCBF and glucose metabolism. We assert that uncoupling of rCBF and oxidative metabolism is a consequence of a less pronounced increase in oxygen consumption. On the basis of earlier studies, we take into consideration the functional recruitment of capillaries and attempt to accommodate the cerebral tissue's increased demand for glucose supply during neural activation with recent evidence supporting a key function for astrocytes in rCBF regulation. PMID:19738630

  8. Bactericidal activity of Ag-doped multi-walled carbon nanotubes and the effects of extracellular polymeric substances and natural organic matter.

    PubMed

    Su, Rina; Jin, Yinjia; Liu, Yang; Tong, Meiping; Kim, Hyunjung

    2013-04-01

    The objective of this study was to determine the bactericidal mechanisms of Ag-doped multi-walled carbon nanotube (MWCNT) nanoparticles (Ag(0)/MWCNTs) to Escherichia coli DH5α. The contributions of silver ion dissolution, reactive species, and direct contact on bacteria inactivation were systematically determined. The relatively higher survival rate of bacteria exposed to 0.02mgL(-1) Ag(+) ions (the maximum concentration of Ag(+) ions dissolved from Ag(0)/MWCNTs) suggested that the antibacterial property of Ag(0)/MWCNTs was not caused by silver ion dissolution. The effects of each reactive species ((·)OH, H(2)O(2), (·)O(2)(-), h(+), and e(-)) on the disinfection process were investigated by using multiple scavengers, and the results showed that (·)OH(b), (·)OH(s), and h(+) play important roles in bactericidal actions. The significance of (·)OH(b), (·)OH(s), and h(+) in the disinfection process was further confirmed in the partition systems combined with scavenger. The antibacterial effects of these reactive species mainly arose through direct contact of the nanocomposites with the bacteria. The effects of extracellular polymeric substances (EPS) and natural organic matter (NOM) on the inactivation of bacteria were also investigated. The lower antibacterial effect observed for EPS-rich bacteria relative to EPS-poor bacteria demonstrated the protective effects of EPS in the disinfection system. The decreased bacterial toxicity effect acquired by the addition of humic acid (as the model NOM) in the disinfection system demonstrated the influence of NOM on the bacterial toxicity of nanocomposites, where the sorption of NOM onto the surface of the nanocomposites contributed to the decreased antibacterial effects.

  9. Bactericidal Permeability-Increasing Proteins Shape Host-Microbe Interactions

    PubMed Central

    Chen, Fangmin; Krasity, Benjamin C.; Peyer, Suzanne M.; Koehler, Sabrina; Ruby, Edward G.

    2017-01-01

    ABSTRACT We characterized bactericidal permeability-increasing proteins (BPIs) of the squid Euprymna scolopes, EsBPI2 and EsBPI4. They have molecular characteristics typical of other animal BPIs, are closely related to one another, and nest phylogenetically among invertebrate BPIs. Purified EsBPIs had antimicrobial activity against the squid’s symbiont, Vibrio fischeri, which colonizes light organ crypt epithelia. Activity of both proteins was abrogated by heat treatment and coincubation with specific antibodies. Pretreatment under acidic conditions similar to those during symbiosis initiation rendered V. fischeri more resistant to the antimicrobial activity of the proteins. Immunocytochemistry localized EsBPIs to the symbiotic organ and other epithelial surfaces interacting with ambient seawater. The proteins differed in intracellular distribution. Further, whereas EsBPI4 was restricted to epithelia, EsBPI2 also occurred in blood and in a transient juvenile organ that mediates hatching. The data provide evidence that these BPIs play different defensive roles early in the life of E. scolopes, modulating interactions with the symbiont. PMID:28377525

  10. Bactericidal antibiotics induce programmed metabolic toxicity

    PubMed Central

    Rowan, Aislinn D.; Cabral, Damien J.; Belenky, Peter

    2016-01-01

    The misuse of antibiotics has led to the development and spread of antibiotic resistance in clinically important pathogens. These resistant infections are having a significant impact on treatment outcomes and contribute to approximately 25,000 deaths in the U.S. annually. If additional therapeutic options are not identified, the number of annual deaths is predicted to rise to 317,000 in North America and 10,000,000 worldwide by 2050. Identifying therapeutic methodologies that utilize our antibiotic arsenal more effectively is one potential way to extend the useful lifespan of our current antibiotics. Recent studies have indicated that modulating metabolic activity is one possible strategy that can impact the efficacy of antibiotic therapy. In this review, we will address recent advances in our knowledge about the impacts of bacterial metabolism on antibiotic effectiveness and the impacts of antibiotics on bacterial metabolism. We will particularly focus on two studies, Lobritz, et al. (PNAS, 112(27): 8173-8180) and Belenky et al. (Cell Reports, 13(5): 968-980) that together demonstrate that bactericidal antibiotics induce metabolic perturbations that are linked to and required for bactericidal antibiotic toxicity.

  11. Bacteria survival probability in bactericidal filter paper.

    PubMed

    Mansur-Azzam, Nura; Hosseinidoust, Zeinab; Woo, Su Gyeong; Vyhnalkova, Renata; Eisenberg, Adi; van de Ven, Theo G M

    2014-05-01

    Bactericidal filter papers offer the simplicity of gravity filtration to simultaneously eradicate microbial contaminants and particulates. We previously detailed the development of biocidal block copolymer micelles that could be immobilized on a filter paper to actively eradicate bacteria. Despite the many advantages offered by this system, its widespread use is hindered by its unknown mechanism of action which can result in non-reproducible outcomes. In this work, we sought to investigate the mechanism by which a certain percentage of Escherichia coli cells survived when passing through the bactericidal filter paper. Through the process of elimination, the possibility that the bacterial survival probability was controlled by the initial bacterial load or the existence of resistant sub-populations of E. coli was dismissed. It was observed that increasing the thickness or the number of layers of the filter significantly decreased bacterial survival probability for the biocidal filter paper but did not affect the efficiency of the blank filter paper (no biocide). The survival probability of bacteria passing through the antibacterial filter paper appeared to depend strongly on the number of collision between each bacterium and the biocide-loaded micelles. It was thus hypothesized that during each collision a certain number of biocide molecules were directly transferred from the hydrophobic core of the micelle to the bacterial lipid bilayer membrane. Therefore, each bacterium must encounter a certain number of collisions to take up enough biocide to kill the cell and cells that do not undergo the threshold number of collisions are expected to survive.

  12. Impact of low-level resistance to fluoroquinolones due to qnrA1 and qnrS1 genes or a gyrA mutation on ciprofloxacin bactericidal activity in a murine model of Escherichia coli urinary tract infection.

    PubMed

    Allou, Nicolas; Cambau, Emmanuelle; Massias, Laurent; Chau, Françoise; Fantin, Bruno

    2009-10-01

    We investigated the impact of low-level resistance to fluoroquinolones on the bactericidal activity of ciprofloxacin in a murine model of urinary tract infection. The susceptible Escherichia coli strain CFT073 (ciprofloxacin MIC [CIP MIC] of 0.008 microg/ml) was compared to its transconjugants harboring qnrA1 or qnrS1 and to an S83L gyrA mutant. The three derivatives showed similar low-level resistance to fluoroquinolones (CIP MICs, 0.25 to 0.5 microg/ml). Bactericidal activity measured in vitro after 1, 3, and 6 h of exposure to 0.5 microg/ml of ciprofloxacin was significantly lower for the derivative strains (P < 0.01). In the murine model of urinary tract infection (at least 45 mice inoculated per strain), mice were treated with a ciprofloxacin regimen of 2.5 mg/kg, given subcutaneously twice daily for 2 days. In mice infected with the susceptible strain, ciprofloxacin significantly decreased viable bacterial counts (log10 CFU/g of tissue) in the bladder (4.2 +/- 0.5 versus 5.5 +/- 1.3; P = 0.001) and in the kidney (3.6 +/- 0.8 versus 5.0 +/- 1.1; P = 0.003) compared with those of untreated mice. In contrast, no significant decrease in viable bacterial counts was observed with any of the three derivative strains. The area under the concentration-time curve from 0 to 24 h/MIC and the maximum concentration of drug in serum/MIC ratios measured in plasma were indeed equal to 827 and 147, respectively, for the parental strain, and only 12.4 to 24.8 and 2.2 to 4.4, respectively, for the derivative strains. In conclusion, low-level resistance to fluoroquinolones conferred by a qnr gene is associated with decreased bactericidal activity of ciprofloxacin, similar to that obtained with a gyrA mutation.

  13. Cerebral blood volume changes during brain activation

    PubMed Central

    Krieger, Steffen Norbert; Streicher, Markus Nikolar; Trampel, Robert; Turner, Robert

    2012-01-01

    Cerebral blood volume (CBV) changes significantly with brain activation, whether measured using positron emission tomography, functional magnetic resonance imaging (fMRI), or optical microscopy. If cerebral vessels are considered to be impermeable, the contents of the skull incompressible, and the skull itself inextensible, task- and hypercapnia-related changes of CBV could produce intolerable changes of intracranial pressure. Because it is becoming clear that CBV may be useful as a well-localized marker of neural activity changes, a resolution of this apparent paradox is needed. We have explored the idea that much of the change in CBV is facilitated by exchange of water between capillaries and surrounding tissue. To this end, we developed a novel hemodynamic boundary-value model and found approximate solutions using a numerical algorithm. We also constructed a macroscopic experimental model of a single capillary to provide biophysical insight. Both experiment and theory model capillary membranes as elastic and permeable. For a realistic change of input pressure, a relative pipe volume change of 21±5% was observed when using the experimental setup, compared with the value of approximately 17±1% when this quantity was calculated from the mathematical model. Volume, axial flow, and pressure changes are in the expected range. PMID:22569192

  14. Biosynthesis of Antitumoral and Bactericidal Sanguinarine

    PubMed Central

    García, Víctor P.; Valdés, F.; Martín, R.; Luis, J. C.; Afonso, A. M.; Ayala, J. H.

    2006-01-01

    A simple, rapid, and reliable TLC method for the separation and determination of sanguinarine has been established. This intensively studied biologically active alkaloid has a wide range of potentially useful medicinal properties, such as antimicrobial, antiinflammatory, and antitumoral activities. Sanguinarine has also been incorporated into expectorant mixtures and has a strong bactericidal effect upon gram-positive bacteria, particularly Bacillus anthracis and staphylococci. These medicinal properties are due to the interaction of sanguinarine with DNA. A fibre-optic-based fluorescence instrument for in situ scanning was used for quantitative measurements. The sanguinarine was determined over the range 5–40 ng and a detection limit of 1.60 ng. The method was applied to the quantification of sanguinarine in tissue culture extracts of Chelidonium majus L. PMID:16883053

  15. The effects of chronic inorganic and organic phosphate exposure on bactericidal activity of the coelomic fluid of the sea urchin Lytechinus variegatus (Lamarck) (Echinodermata: Echinoidea).

    PubMed

    Böttger, S Anne; McClintock, James B

    2009-07-01

    The sea urchin Lytechinus variegatus can survive chronic exposure to sodium phosphate (inorganic phosphate) concentrations as high as 3.2 mg L-1, and triethyl phosphate (organic phosphate) concentrations of 1000 mg L-1. However, chronic exposure to low (0.8 mg L-1 inorganic and 10 mg L-1 organic phosphate), medium (1.6 mg L-1 inorganic and 100 mg L-1 organic phosphate) or high (3.2 mg L-1 inorganic and 1000 mg L-1 organic phosphate) sublethal concentrations of these phosphates inhibit bactericidal clearance of the marine bacterium Vibrio sp. Bacteria were exposed to coelomic fluid collected from individuals maintained in either artificial seawater, or three concentrations of either inorganic phosphate or organic phosphate. Sterile marine broth, natural seawater and cell free coelomic fluid (cfCF) were employed as controls. Bacterial survival indices were measured at 0, 24 and 48 h periods once a week for four weeks. Bacteria were readily eliminated from the whole coelomic fluid (wCF) of individuals maintained in artificial seawater. Individuals maintained in inorganic phosphates were able to clear bacteria following a two week exposure period, while individuals maintained at even low concentrations of organic phosphates failed to clear all bacteria from their coelomic fluid. Exposure to phosphates represses antimicrobial defenses and may ultimately compromise survival of L. variegatus in the nearshore environment.

  16. Properdin is critical for antibody-dependent bactericidal activity against Neisseria gonorrhoeae that recruit C4b-binding protein1

    PubMed Central

    Gulati, Sunita; Agarwal, Sarika; Vasudhev, Shreekant; Rice, Peter A.; Ram, Sanjay

    2012-01-01

    Gonorrhea, a sexually transmitted disease caused by Neisseria gonorrhoeae, is an important cause of morbidity worldwide. A safe and effective vaccine against gonorrhea is needed because of emerging resistance of gonococci to almost every class of antibiotic. A gonococcal lipooligosaccharide (LOS) epitope defined by the monoclonal antibody (mAb), 2C7, is being evaluated as a candidate for development of an antibody-based vaccine. Immune antibodies against N. gonorrhoeae need to overcome several subversive mechanisms whereby gonococcus evades complement, including binding to C4b-binding protein (C4BP; classical pathway inhibitor) and factor H (alternative pathway [AP] inhibitor). The role of AP recruitment and in particular properdin in assisting killing of gonococci by specific antibodies is the subject of this study. We show that only those gonococcal strains that bind C4BP require properdin for killing by 2C7, whereas strains that do not bind C4BP are efficiently killed by 2C7 even when AP function is blocked. C3 deposition on bacteria mirrored killing. Recruitment of the AP by mAb 2C7, as measured by factor B binding, occurred in a properdin-dependent manner. These findings were confirmed using isogenic mutant strains that differed in their ability to bind to C4BP. Immune human serum that contained bactericidal antibodies directed against the 2C7 LOS epitope as well as murine anti-gonococcal antiserum, required functional properdin to kill C4BP binding strains, but not C4BP non-binding strains. Collectively, these data point to an important role for properdin in facilitating immune antibody-mediated complement-dependent killing of gonococcal strains that inhibit the classical pathway by recruiting C4BP. PMID:22368277

  17. Effect of blood activity on dosimetric calculations for radiopharmaceuticals

    NASA Astrophysics Data System (ADS)

    Zvereva, Alexandra; Petoussi-Henss, Nina; Li, Wei Bo; Schlattl, Helmut; Oeh, Uwe; Zankl, Maria; Graner, Frank Philipp; Hoeschen, Christoph; Nekolla, Stephan G.; Parodi, Katia; Schwaiger, Markus

    2016-11-01

    The objective of this work was to investigate the influence of the definition of blood as a distinct source on organ doses, associated with the administration of a novel radiopharmaceutical for positron emission tomography-computed tomography (PET/CT) imaging—(S)-4-(3-18F-fluoropropyl)-L-glutamic acid (18F-FSPG). Personalised pharmacokinetic models were constructed based on clinical PET/CT images from five healthy volunteers and blood samples from four of them. Following an identifiability analysis of the developed compartmental models, person-specific model parameters were estimated using the commercial program SAAM II. Organ doses were calculated in accordance to the formalism promulgated by the Committee on Medical Internal Radiation Dose (MIRD) and the International Commission on Radiological Protection (ICRP) using specific absorbed fractions for photons and electrons previously derived for the ICRP reference adult computational voxel phantoms. Organ doses for two concepts were compared: source organ activities in organs parenchyma with blood as a separate source (concept-1); aggregate activities in perfused source organs without blood as a distinct source (concept-2). Aggregate activities comprise the activities of organs parenchyma and the activity in the regional blood volumes (RBV). Concept-1 resulted in notably higher absorbed doses for most organs, especially non-source organs with substantial blood contents, e.g. lungs (92% maximum difference). Consequently, effective doses increased in concept-1 compared to concept-2 by 3-10%. Not considering the blood as a distinct source region leads to an underestimation of the organ absorbed doses and effective doses. The pronounced influence of the blood even for a radiopharmaceutical with a rapid clearance from the blood, such as 18F-FSPG, suggests that blood should be introduced as a separate compartment in most compartmental pharmacokinetic models and blood should be considered as a distinct source in

  18. Blood group isoantibody stimulation in man by feeding blood group-active bacteria

    PubMed Central

    Springer, Georg F.; Horton, Richard E.

    1969-01-01

    It was investigated whether or not the human blood group isoantibodies A and B could be induced by immunogenic stimuli via natural routes with a kind of antigenic substance to which all humans are commonly exposed, or if the appearance of these antibodies is independent of antigenic stimuli as has long been believed. Escherichia coli O86, which possess high human blood group B and faint A activity in vitro, were fed to healthy humans and those with intestinal disorders. 80% of the sick individuals of blood group O and A responded with a significant rise of anti-B antibodies which was frequently de novo in infants; significant increase of anti-A isoantibodies among blood group O individuals was less frequent. Over one-third of the healthy individuals also had a significant isoantibody increase. Intestinal lesions favor isoantibody stimulation by intestinal bacteria; this view was supported by the study of control infants. Persons of blood group A responded more frequently with anti-B and anti-E. coli O86 antibody production than those of blood group O. Isoantibody increase was accompanied with antibody rise against E. coli O86. Inhalation of E. coli O86 or blood group AH(O)-specific hog mucin also evoked isoantibodies. The induced isoantibodies were specifically inhibited by small amounts of human blood group substances. E. coli O86-induced anti-blood group antibodies in germ-free chickens and preexisting blood group antibodies in ordinary chickens were neutralized by intravenous injection of E. coli O86 lipopolysaccharide. This study demonstrates that human isoantibodies A and B are readily elicited via physiological routes, by blood group-active E. coli, provided the genetically determined apparatus of the host is responsive. Antibodies against a person's own blood group were not formed. Interpretation of these results permits some careful generalizations as to the origin of so-called natural antibodies. PMID:4893685

  19. Identification of highly active flocculant proteins in bovine blood.

    PubMed

    Piazza, George J; Nuñez, Alberto; Garcia, Rafael A

    2012-03-01

    Synthetic polymeric flocculants are used extensively for wastewater remediation, soil stabilization, and reduction in water leakage from unlined canals. Sources of highly active, inexpensive, renewable flocculants are needed to replace synthetic flocculants. High kaolin flocculant activity was documented for bovine blood (BB) and blood plasma with several anticoagulant treatments. BB serum also had high flocculant activity. To address the hypothesis that some blood proteins have strong flocculating activity, the BB proteins were separated by SEC. Then, the major proteins of the flocculant-active fractions were separated by SDS-PAGE. Identity of the major protein components was determined by tryptic digestion and peptide analysis by MALDI TOF MS. The sequence of selected peptides was confirmed using TOF/TOF-MS/MS fragmentation. Hemoglobin dimer (subunits α and β) was identified as the major protein component of the active fraction in BB; its high flocculation activity was confirmed by testing a commercial sample of hemoglobin. In the same manner, three proteins from blood plasma (fibrinogen, γ-globulin, α-2-macroglobulin) were found to be highly active flocculants, but bovine serum albumin, α-globulin, and β-globulin were not flocculants. On a mass basis, hemoglobin, γ-globulin, α-2-macroglobulin were as effective as anionic polyacrylamide (PAM), a widely used synthetic flocculant. The blood proteins acted faster than PAM, and unlike PAM, the blood proteins flocculants did not require calcium salts for their activity.

  20. In vitro and in vivo activities of E-101 solution against Acinetobacter baumannii isolates from U.S. military personnel.

    PubMed

    Denys, G A; Davis, J C; O'Hanley, P D; Stephens, J T

    2011-07-01

    We evaluated the in vitro and in vivo activity of a novel topical myeloperoxidase-mediated antimicrobial, E-101 solution, against 5 multidrug-resistant Acinetobacter baumannii isolates recovered from wounded American soldiers. Time-kill studies demonstrated rapid bactericidal activity against all A. baumannii strains tested in the presence of 3% blood. The in vitro bactericidal activity of E-101 solution against A. baumannii strains was confirmed in a full-thickness excision rat model. Additional in vivo studies appear warranted.

  1. Identification of highly active flocculant proteins in bovine blood

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Bovine blood is an excellent flocculating agent, faster acting and as effective on a mass basis as polyacrylamide, the most widely utilized polymeric flocculant. To determine the molecular basis of flocculation activity, whole bovine blood (BB) and BB plasma were fractionated by size exclusion chro...

  2. [Activation and inhibitory mechanisms of blood platelets].

    PubMed

    Suzuki-Inoue, Katsue

    2014-07-01

    Exposure of platelets to subendothelial matrices initiates physiological hemostasis and pathological thrombosis. Under high shear stress, von Willebrand factor bridges newly exposed collagen to glycoprotein (GP) Ib on platelets. This initial tethering facilitates association between the collagen receptor GPVI and collagen, which generates tyrosine kinase-dependent activation signals, followed by release of secondary mediators and integrin activation. Activated integrin can bind to their ligands including fibrinogen. The released secondary mediators, ADP and thromboxane A2, activate integrin of flowing platelets, which enables formation of platelet thrombi by binding of activated flowing platelets and adhered platelets to collagen via binding between activated aIIbbeta3 integrin and fibrinogen. Platelets also have inhibitory mechanisms, which help to prevent unwanted platelet activation in vivo.

  3. Whole Blood Cholinesterase Activity in 20 Species of Wild Birds.

    PubMed

    Horowitz, Igal H; Yanco, Esty G; Landau, Shmulik; Nadler-Valency, Rona; Anglister, Nili; Bueller-Rosenzweig, Ariela; Apelbom-Halbersberg, Tal; Cuneah, Olga; Hanji, Vera; Bellaiche, Michel

    2016-06-01

    Clinical signs of organophosphate and carbamate intoxication in wild birds can be mistaken for those of other diseases, thus potentially delaying diagnosis and implementation of life-saving treatment. The objective of this study was to determine the reference interval for blood cholinesterase activity in 20 different wild avian species from 7 different orders, thereby compiling a reference database for wildlife veterinarians. Blood was collected from birds not suspected of having organophosphate or carbamate toxicosis, and the modified Michel method, which determines the change in blood pH that directly correlates with cholinesterase activity, was used to measure blood cholinesterase levels. Results of change in blood pH values ranged from 0.11 for the white-tailed eagle ( Haliaeetus albicilla ) to 0.90 for the honey buzzard ( Pernis apivorus ). The results showed that even within the same family, interspecies differences in normal cholinesterase blood activity were not uncommon. The findings emphasized the importance of determining reference intervals for avian blood cholinesterase activity at the species level.

  4. Plasmid-determined resistance to serum bactericidal activity: a major outer membrane protein, the traT gene product, is responsible for plasmid-specified serum resistance in Escherichia coli.

    PubMed Central

    Moll, A; Manning, P A; Timmis, K N

    1980-01-01

    Resistance to the bactericidal activity of serum appears to be an important virulence property of invasive bacteria. The conjugative multiple-antibiotic-resistance plasmid R6-5 was found to confer upon Escherichia coli host bacteria increased resistance against rabbit serum. Gene-cloning techniques were used to localize the serum resistance determinant of R6-5 to a segment of the plasmid that encodes conjugal transfer functions, and a pACYC184 hybrid plasmid, designated pKT107, that contains this segment was constructed. The generation and analysis of deletion and insertion mutant derivatives of the pKT107 plasmid that no longer specify serum resistance permitted precise localization of the serum-resistance cistron on the R6-5 map and demonstrated that this locus is coincident with that of traT, one of the two surface exclusion genes of R6-5. Examination of the proteins synthesized in E. coli minicells of pKT107 and its serum-sensitive mutant derivative plasmids confirmed that the serum-resistance gene product of R6-5 is the traT protein and showed that this protein is a major structural component (about 21,000 copies per cell) of the bacterial outer membrane. Images Fig. 3 Fig. 4 Fig. 5 Fig. 6 PMID:6995306

  5. Palmitoleic acid calcium salt: a lubricant and bactericidal powder from natural lipids.

    PubMed

    Yamamoto, Yoshiaki; Kawamura, Yuki; Yamazaki, Yuki; Kijima, Tatsuro; Morikawa, Toshiya; Nonomura, Yoshimune

    2015-01-01

    Palmitoleic acid is a promising bactericidal agent for cleansing products with alternative bactericidal abilities. In this study, we focus on the physical and biological activity of palmitoleic acid calcium salt (C16:1 fatty acid Ca salt) because it forms via an ion-exchange reaction between palmitoleic acid and Ca ions in tap water, and remains on the skin surface during the cleansing process. Here, we prepared C16:1 fatty acid Ca salt to investigate its crystal structure and physical and bactericidal properties. The Ca salt was a plate-shaped lamellar crystalline powder with a particle diameter of several micrometers to several tens of micrometers; it exhibited significant lubricity and alternative bactericidal activity against Staphylococcus aureus (S. aureus) and Propionibacterium acnes (P. acnes). We also examined other fatty acid Ca salts prepared from lauric acid (C12:0 fatty acid), palmitic acid (C16:0 fatty acid), and oleic acid (C18:1 fatty acid). The bactericidal activities and lubricity of the fatty acid Ca salts changed with the alkyl chain length and the degree of unsaturation. The C16:1 fatty acid Ca salt exhibited the strongest selective bactericidal ability among the four investigated fatty acid Ca salts. These findings suggest that C16:1 fatty acid and its Ca salt have potential applications in cleansing and cosmetic products.

  6. Diastereomeric bactericidal effect of Ru(phenanthroline)2dipyridophenazine

    PubMed Central

    Bergentall, Mattias; Tremaroli, Valentina; Lincoln, Per

    2016-01-01

    ABSTRACT Metal susceptibility assays and spot plating were used to investigate the antimicrobial activity of enantiopure [Ru(phen)2dppz]2+ (phen =1,10‐phenanthroline and dppz = dipyrido[3,2‐a:2´,3´‐c]phenazine) and [μ‐bidppz(phen)4Ru2]4 + (bidppz =11,11´‐bis(dipyrido[3,2‐a:2´,3´‐c]phenazinyl)), on Gram‐negative Escherichia coli and Gram‐positive Bacillus subtilis as bacterial models. The minimum inhibitory concentrations (MIC) and minimum bactericidal concentrations (MBC) were determined for both complexes: while [μ‐bidppz(phen)4Ru2]4 + only showed a bactericidal effect at the highest concentrations tested, the antimicrobial activity of [Ru(phen)2dppz]2+ against B. subtilis was comparable to that of tetracyline. In addition, the Δ‐enantiomer of [Ru(phen)2dppz]2+ showed a 2‐fold higher bacteriostatic and bactericidal effect compared to the Λ‐enantiomer. This was in accordance with the enantiomers relative binding affinity for DNA, thus strongly indicating DNA binding as the mode of action. PMID:27791316

  7. Bactericidal Effects of Natural Nanotopography of Dragonfly Wing on Escherichia coli.

    PubMed

    Bandara, Chaturanga D; Singh, Sanjleena; Afara, Isaac O; Wolff, Annalena; Tesfamichael, Tuquabo; Ostrikov, Kostya; Oloyede, Adekunle

    2017-03-01

    Nanotextured surfaces (NTSs) are critical to organisms as self-adaptation and survival tools. These NTSs have been actively mimicked in the process of developing bactericidal surfaces for diverse biomedical and hygiene applications. To design and fabricate bactericidal topographies effectively for various applications, understanding the bactericidal mechanism of NTS in nature is essential. The current mechanistic explanations on natural bactericidal activity of nanopillars have not utilized recent advances in microscopy to study the natural interaction. This research reveals the natural bactericidal interaction between E. coli and a dragonfly wing's (Orthetrum villosovittatum) NTS using advanced microscopy techniques and proposes a model. Contrary to the existing mechanistic models, this experimental approach demonstrated that the NTS of Orthetrum villosovittatum dragonfly wings has two prominent nanopillar populations and the resolved interface shows membrane damage occurred without direct contact of the bacterial cell membrane with the nanopillars. We propose that the bacterial membrane damage is initiated by a combination of strong adhesion between nanopillars and bacterium EPS layer as well as shear force when immobilized bacterium attempts to move on the NTS. These findings could help guide the design of novel biomimetic nanomaterials by maximizing the synergies between biochemical and mechanical bactericidal effects.

  8. A Cleavage-potentiated Fragment of Tear Lacritin Is Bactericidal*

    PubMed Central

    McKown, Robert L.; Coleman Frazier, Erin V.; Zadrozny, Kaneil K.; Deleault, Andrea M.; Raab, Ronald W.; Ryan, Denise S.; Sia, Rose K.; Lee, Jae K.; Laurie, Gordon W.

    2014-01-01

    Antimicrobial peptides are important as the first line of innate defense, through their tendency to disrupt bacterial membranes or intracellular pathways and potentially as the next generation of antibiotics. How they protect wet epithelia is not entirely clear, with most individually inactive under physiological conditions and many preferentially targeting Gram-positive bacteria. Tears covering the surface of the eye are bactericidal for Gram-positive and -negative bacteria. Here we narrow much of the bactericidal activity to a latent C-terminal fragment in the prosecretory mitogen lacritin and report that the mechanism combines membrane permeabilization with rapid metabolic changes, including reduced levels of dephosphocoenzyme A, spermidine, putrescine, and phosphatidylethanolamines and elevated alanine, leucine, phenylalanine, tryptophan, proline, glycine, lysine, serine, glutamate, cadaverine, and pyrophosphate. Thus, death by metabolic stress parallels cellular attempts to survive. Cleavage-dependent appearance of the C-terminal cationic amphipathic α-helix is inducible within hours by Staphylococcus epidermidis and slowly by another mechanism, in a chymotrypsin- or leupeptin protease-inhibitable manner. Although bactericidal at low micromolar levels, within a biphasic 1–10 nm dose optimum, the same domain is mitogenic and cytoprotective for epithelia via a syndecan-1 targeting mechanism dependent on heparanase. Thus, the C terminus of lacritin is multifunctional by dose and proteolytic processing and appears to play a key role in the innate protection of the eye, with wider potential benefit elsewhere as lacritin flows from exocrine secretory cells. PMID:24942736

  9. Improving the Lethal Effect of Cpl-7, a Pneumococcal Phage Lysozyme with Broad Bactericidal Activity, by Inverting the Net Charge of Its Cell Wall-Binding Module

    PubMed Central

    Díez-Martínez, Roberto; de Paz, Héctor; Bustamante, Noemí; García, Ernesto; Menéndez, Margarita

    2013-01-01

    Phage endolysins are murein hydrolases that break the bacterial cell wall to provoke lysis and release of phage progeny. Recently, these enzymes have also been recognized as powerful and specific antibacterial agents when added exogenously. In the pneumococcal system, most cell wall associated murein hydrolases reported so far depend on choline for activity, and Cpl-7 lysozyme constitutes a remarkable exception. Here, we report the improvement of the killing activity of the Cpl-7 endolysin by inversion of the sign of the charge of the cell wall-binding module (from −14.93 to +3.0 at neutral pH). The engineered variant, Cpl-7S, has 15 amino acid substitutions and an improved lytic activity against Streptococcus pneumoniae (including multiresistant strains), Streptococcus pyogenes, and other pathogens. Moreover, we have demonstrated that a single 25-μg dose of Cpl-7S significantly increased the survival rate of zebrafish embryos infected with S. pneumoniae or S. pyogenes, confirming the killing effect of Cpl-7S in vivo. Interestingly, Cpl-7S, in combination with 0.01% carvacrol (an essential oil), was also found to efficiently kill Gram-negative bacteria such as Escherichia coli and Pseudomonas putida, an effect not described previously. Our findings provide a strategy to improve the lytic activity of phage endolysins based on facilitating their pass through the negatively charged bacterial envelope, and thereby their interaction with the cell wall target, by modulating the net charge of the cell wall-binding modules. PMID:23959317

  10. Use of agar diffusion assay to measure bactericidal activity of alkaline salts of fatty acids against bacteria associated with poultry processing

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The agar diffusion assay was used to examine antibacterial activity of alkaline salts of caproic, caprylic, capric, lauric, and myristic acids. A 0.5M concentration of each fatty acid was dissolved in 1.0 M potassium hydroxide (KOH), and pH of the mixtures was adjusted to 10.5 with citric acid. Solu...

  11. Use of agar diffusion assay to evaluate bactericidal activity of formulations of alkaline salts of fatty acids against bacteria associated with poultry processing

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The agar diffusion assay was used to examine antibacterial activity of alkaline salts of fatty acids (FA). Wells in agar media seeded with bacteria were filled with FA-potassium hydroxide (KOH) solutions, plates were incubated, and zones of inhibition were measured. The relationship between bacteric...

  12. Bactericidal antibiotics induce mitochondrial dysfunction and oxidative damage in Mammalian cells.

    PubMed

    Kalghatgi, Sameer; Spina, Catherine S; Costello, James C; Liesa, Marc; Morones-Ramirez, J Ruben; Slomovic, Shimyn; Molina, Anthony; Shirihai, Orian S; Collins, James J

    2013-07-03

    Prolonged antibiotic treatment can lead to detrimental side effects in patients, including ototoxicity, nephrotoxicity, and tendinopathy, yet the mechanisms underlying the effects of antibiotics in mammalian systems remain unclear. It has been suggested that bactericidal antibiotics induce the formation of toxic reactive oxygen species (ROS) in bacteria. We show that clinically relevant doses of bactericidal antibiotics-quinolones, aminoglycosides, and β-lactams-cause mitochondrial dysfunction and ROS overproduction in mammalian cells. We demonstrate that these bactericidal antibiotic-induced effects lead to oxidative damage to DNA, proteins, and membrane lipids. Mice treated with bactericidal antibiotics exhibited elevated oxidative stress markers in the blood, oxidative tissue damage, and up-regulated expression of key genes involved in antioxidant defense mechanisms, which points to the potential physiological relevance of these antibiotic effects. The deleterious effects of bactericidal antibiotics were alleviated in cell culture and in mice by the administration of the antioxidant N-acetyl-l-cysteine or prevented by preferential use of bacteriostatic antibiotics. This work highlights the role of antibiotics in the production of oxidative tissue damage in mammalian cells and presents strategies to mitigate or prevent the resulting damage, with the goal of improving the safety of antibiotic treatment in people.

  13. Bactericidal Antibiotics Induce Mitochondrial Dysfunction and Oxidative Damage in Mammalian Cells

    PubMed Central

    Costello, James C.; Liesa, Marc; Morones-Ramirez, J Ruben; Slomovic, Shimyn; Molina, Anthony; Shirihai, Orian S.; Collins, James J.

    2013-01-01

    Prolonged antibiotic treatment can lead to detrimental side effects in patients, including ototoxicity, nephrotoxicity, and tendinopathy, yet the mechanisms underlying the effects of antibiotics in mammalian systems remain unclear. It has been suggested that bactericidal antibiotics induce the formation of toxic reactive oxygen species (ROS) in bacteria. We show that clinically relevant doses of bactericidal antibiotics—quinolones, aminoglycosides, and β-lactams—cause mitochondrial dysfunction and ROS overproduction in mammalian cells. We demonstrate that these bactericidal antibiotic–induced effects lead to oxidative damage to DNA, proteins, and membrane lipids. Mice treated with bactericidal antibiotics exhibited elevated oxidative stress markers in the blood, oxidative tissue damage, and up-regulated expression of key genes involved in antioxidant defense mechanisms, which points to the potential physiological relevance of these antibiotic effects. The deleterious effects of bactericidal antibiotics were alleviated in cell culture and in mice by the administration of the antioxidant N-acetyl-L-cysteine or prevented by preferential use of bacteriostatic antibiotics. This work highlights the role of antibiotics in the production of oxidative tissue damage in mammalian cells and presents strategies to mitigate or prevent the resulting damage, with the goal of improving the safety of antibiotic treatment in people. PMID:23825301

  14. Exploring a new phenomenon in the bactericidal response of TiO2 thin films by Fe doping: Exerting the antimicrobial activity even after stoppage of illumination

    NASA Astrophysics Data System (ADS)

    Naghibi, Sanaz; Vahed, Shohreh; Torabi, Omid; Jamshidi, Amin; Golabgir, Mohammad Hossein

    2015-02-01

    Antibacterial properties of Fe-doped TiO2 thin films prepared on glass by the sol-gel hot-dipping technique were studied. The films were characterized by X-ray diffraction, field emission scanning electron microscopy, scanning probe microscopy and X-ray photoelectron spectroscopy. The photocatalytic activities were evaluated by measuring the decomposition rate of methylene blue under ultra violet and visible light. The antibacterial properties of the coatings were investigated against Escherichia coli, Staphylococcus aureus, Saccharomyces cerevisia and Aspergillus niger. The principle of incubation methods was also discussed. The results indicated that Fe doping of thin films eventuated in high antibacterial properties under visible light and this performance remained even after stoppage of illumination. This article tries to provide some explanation for this fact.

  15. Bactericidal Mechanisms of Ag2O/TNBs under both Dark and Light Conditions

    NASA Astrophysics Data System (ADS)

    Jin, Yinjia; Dai, Zhaoyi; Liu, Fei; Kim, Hyunjung; Tong, Meiping; Hou, Yanglong

    2013-04-01

    Ag2O deposited titanium dioxides nanobelts (Ag2O/TNBs) were fabricated and used to investigate the toxic effects on aquatic microorganisms. The disinfection activities of Ag2O/TNBs on two representative bacterial strains: Gram-negative E. coli and Gram-positive B. subtilis, were examined under both dark and light conditions. Ag2O/TNBs exhibited stronger bactericidal activities than TNBs under both dark and light conditions. For both cell types, disinfection effects of Ag2O/TNBs were greater under light conditions relative to those under dark conditions. The bactericidal mechanisms of Ag2O/TNBs under both dark and light conditions were explored. Under dark conditions, neither Ag+ ions released from Ag2O/TNBs nor TNBs contributed to the bactericidal activities of Ag2O/TNBs. Under light conditions, both the released Ag+ions and TNBs yet were found to have contributions to the bactericidal effects of Ag2O/TNBs. Active species (H2O2, ?O2-, ande-) generated by Ag2O/TNBs played important roles in the disinfection processes under both dark and light conditions. Without the presence of active species, the direct contact of Ag2O/TNBs with bacterial cells had no bactericidal effect.

  16. CatB is Critical for Total Catalase Activity and Reduces Bactericidal Effects of Phenazine-1-Carboxylic Acid on Xanthomonas oryzae pv. oryzae and X. oryzae pv. oryzicola.

    PubMed

    Pan, Xiayan; Wu, Jian; Xu, Shu; Duan, Yabing; Zhou, Mingguo

    2017-02-01

    Rice bacterial leaf blight, caused by Xanthomonas oryzae pv. oryzae, and rice bacterial leaf streak, caused by X. oryzae pv. oryzicola, are major diseases of rice. Phenazine-1-carboxylic acid (PCA) is a natural product that is isolated from Pseudomonas spp. and is used to control many important rice diseases in China. We previously reported that PCA disturbs the redox balance, which results in the accumulation of reactive oxygen species in X. oryzae pv. oryzae. In this study, we found that PCA significantly upregulated the transcript levels of catB and katE, which encode catalases, and that PCA sensitivity was reduced when X. oryzae pvs. oryzae and oryzicola were cultured with exogenous catalase. Furthermore, catB deletion mutants of X. oryzae pvs. oryzae and oryzicola showed dramatically decreased total catalase activity, increased sensitivity to PCA, and reduced virulence in rice. In contrast, deletion mutants of srpA and katG, which also encode catalases, exhibited little change in PCA sensitivity. The results indicate that catB in both X. oryzae pvs. oryzae and oryzicola encodes a catalase that helps protect the bacteria against PCA-induced stress.

  17. A new method for producing highly concentrated non-aqueous dispersions of silver nanoparticles and the evaluation of their bactericidal activity

    NASA Astrophysics Data System (ADS)

    da S. Oliveira, Roselaine; Bizeto, Marcos A.; Liberatore, Ana M. A.; Koh, Ivan H. J.; Camilo, Fernanda F.

    2014-11-01

    Different preparation methods of silver nanoparticles (AgNP) are well described in the literature, most of them in aqueous medium. Aqueous dispersions of AgNP normally have a limited capacity to tolerate high nanosilver concentrations. However, AgNP production in non-aqueous medium is still scarce although its exploitation for example, as coating for hydrophobic surfaces, would be of a huge importance in many technological applications. In this work, we report the chemical preparation of highly concentrated non-aqueous AgNP dispersions obtained by reduction of silver cation, from two distinct salt sources (AgNO3 and AgBF4), by 1-butanol in the presence of a biocompatible poly(ether-block-amide) copolymer, named PEBA. The highest concentration reached was around 5 mM, when it used AgBF4 as silver source and 4 % (w/w) of a PEBA solution in 1-butanol. This AgNP concentration is notably higher than the values reported in aqueous medium. The AgNP formation was attested by UV-Vis spectroscopic analysis, which showed the characteristic strong plasmon band at 420 nm. The X-ray diffraction patterns confirmed the formation of a crystalline fcc silver metallic phase with particle diameters ranging from 5 to 10 nm accordingly to transmission electron microscopy examination. It was also observed that the AgNP dimensions are dependent on the PEBA and silver salt concentrations. The AgNP dispersions presented a very high antimicrobial activity against E. coli and S. aureus microorganisms, even in low concentration, attested by the Kirby-Bauer method.

  18. Blood

    MedlinePlus

    ... The liquid part, called plasma, is made of water, salts, and protein. Over half of your blood is plasma. The solid part of your blood contains red blood cells, white blood cells, and platelets. Red ...

  19. Functional Nanoparticles Activate a Decellularized Liver Scaffold for Blood Detoxification.

    PubMed

    Xu, Fen; Kang, Tianyi; Deng, Jie; Liu, Junli; Chen, Xiaolei; Wang, Yuan; Ouyang, Liang; Du, Ting; Tang, Hong; Xu, Xiaoping; Chen, Shaochen; Du, Yanan; Shi, Yujun; Qian, Zhiyong; Wei, Yuquan; Deng, Hongxin; Gou, Maling

    2016-04-01

    Extracorporeal devices have great promise for cleansing the body of virulence factors that are caused by venomous injuries, bacterial infections, and biological weaponry. The clinically used extracorporeal devices, such as artificial liver-support systems that are mainly based on dialysis or electrostatic interaction, are limited to remove a target toxin. Here, a liver-mimetic device is shown that consists of decellularized liver scaffold (DLS) populated with polydiacetylene (PDA) nanoparticles. DLS has the gross shape and 3D architecture of a liver, and the PDA nanoparticles selectively capture and neutralize the pore-forming toxins (PFTs). This device can efficiently and target-orientedly remove PFTs in human blood ex vivo without changing blood components or activating complement factors, showing potential application in antidotal therapy. This work provides a proof-of-principle for blood detoxification by a nanoparticle-activated DLS, and can lead to the development of future medical devices for antidotal therapy.

  20. Performance of a coincidence based blood activity monitor

    SciTech Connect

    Moses, W.W.

    1989-12-01

    A new device has been constructed that measures the positron emitting radio-tracer concentration in arterial blood by extracting blood with a peristaltic pump, then measuring the activity concentration by detecting coincident pairs of 511 keV photons with a pair of heavy inorganic scintillators attached to photomultiplier tubes. The sensitivity of this device is experimentally determined to be 610 counts/second per {mu}Ci/ml, and has a paralyzing dead time of 1.2 {mu}s, so is capable of measuring blood activity concentration as high as 1 mCi/ml. Its performance is compared to two other blood monitoring methods: discrete blood samples counted with a well counter and device that uses a plastic scintillator to directly detect positrons. The positron detection efficiency of this device for {sup 18}F is greater than the plastic scintillation counter, and also eliminates the radioisotope dependent correction factors necessary to convert count rate to absolute concentration. Coincident photon detection also has the potential of reducing the background compared to direct positron detection, thereby increasing the minimum detectable isotope concentration. 10 refs., 6 figs.

  1. Effect of bromidehypochlorite bactericides on microorganisms.

    PubMed

    SHERE, L; KELLEY, M J; RICHARDSON, J H

    1962-11-01

    A new principle in compounding stable, granular bactericidal products led to unique combinations of a water-soluble inorganic bromide salt with a hypochlorite-type disinfectant of either inorganic or organic type. Microbiological results are shown for an inorganic bactericide composed of chlorinated trisodium phosphate containing 3.1% "available chlorine" and 2% potassium bromide, and for an organic bactericide formulated from sodium dichloroisocyanurate so as to contain 13.4% "available chlorine" and 8% potassium bromide. Comparison of these products with their nonbromide counterparts are reported for Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, Streptococcus lactis, Aerobacter aerogenes, and Proteus vulgaris. Test methods employed were the Chambers test, the A.O.A.C. Germicidal and Detergent Sanitizer-Official test, and the Available Chlorine Germicidal Equivalent Concentration test. The minimal killing concentrations for the bromide-hypochlorite bactericides against this variety of organisms were reduced by a factor 2 to 24 times those required for similar hypochlorite-type disinfectants not containing the bromide.

  2. Subcellular location and properties of bactericidal factors from human neutrophils.

    PubMed

    Gabay, J E; Heiple, J M; Cohn, Z A; Nathan, C F

    1986-11-01

    We examined the subcellular location of bactericidal factors (BF) in human neutrophils, using an efficient fractionation scheme. Nitrogen bomb cavitates of DIFP-treated PMN were centrifuged through discontinuous Percoll gradients, each fraction extracted with 0.05 M glycine, pH 2.0, and tested for the killing of Escherichia coli. greater than 90% of BF coisolated with the azurophil granules. After lysis of azurophils, 98% of azurophil-derived BF (ADBF) sedimented with the membrane. ADBF activity was solubilized from azurophil membrane with either acid or nonionic detergent (Triton X-100, Triton X-114). Bactericidal activity was linear with respect to protein concentration over the range 0.3-30 micrograms/ml. 0.1-0.3 microgram/ml ADBF killed 10(5) E. coli within 30 min at 37 degrees C. At 1.4 micrograms/ml, 50% of 2 X 10(5) bacteria were killed within 5 min. ADBF was effective between pH 5-8, with peak activity at pH 5.5. Glucose (20 mM), EDTA (1-25 mM), and physiologic concentrations of NaCl or KCl had little or no inhibitory effect on ADBF. ADBF killed both Gram-positive and Gram-negative virulent clinical isolates, including listeria, staphylococci, beta-hemolytic streptococci, and Pseudomonas aeruginosa. Thus, under these conditions of cell disruption, fractionation, extraction, and assay, almost all BF in human PMN appeared to be localized to the membrane of azurophilic granules as a highly potent, broad-spectrum, rapidly acting protein(s) effective in physiologic medium. Some of these properties appear to distinguish ADBF from previously described PMN bactericidal proteins.

  3. A comparison of kaolin-activated versus nonkaolin-activated thromboelastography in native and citrated blood.

    PubMed

    Thalheimer, Ulrich; Triantos, Christos K; Samonakis, Dimitrios N; Zambruni, Andrea; Senzolo, Marco; Leandro, Gioacchino; Patch, David; Burroughs, Andrew K

    2008-09-01

    Thromboelastography can be performed with native or citrated blood (a surrogate to native blood in healthy controls, surgical and cirrhotic patients). Activators such as kaolin are increasingly used to reduce the time to trace generation. To compare kaolin-activated thromboelastography with nonkaolin-activated thromboelastography of native and citrated blood in patients with liver disease, patients undergoing treatment with warfarin or low-molecular weight heparin and healthy volunteers. We studied thromboelastography parameters in 21 healthy volunteers (group 1) and 50 patients, including 20 patients with liver cirrhosis with a nonbiliary aetiology (group 2), 10 patients with primary biliary cirrhosis or primary sclerosing cholangitis (group 3), 10 patients on warfarin treatment (group 4) and 10 patients with enoxaparin prophylaxis (group 5). Thromboelastography was performed using four methods: native blood (kaolin-activated and nonkaolin-activated) and citrated blood (kaolin-activated and nonkaolin-activated). For all thromboelastography parameters, correlation was poor (Spearman correlation coefficient < 0.70) between nonkaolin-activated and kaolin-activated thromboelastography, for both citrated and native blood. In healthy volunteers, in patients with liver disease and in those receiving anticoagulant treatment, there was a poor correlation between nonkaolin-activated and kaolin-activated thromboelastography. Kaolin-activated thromboelastography needs further validation before routine clinical use in these settings, and the specific methodology must be considered in comparing published studies.

  4. Systemic blood coagulation activation in acute coronary syndromes

    PubMed Central

    Undas, Anetta; Szułdrzyński, Konstanty; Brummel-Ziedins, Kathleen E.; Tracz, Wiesława; Zmudka, Krzysztof

    2009-01-01

    We evaluated systemic alterations to the blood coagulation system that occur during a coronary thrombotic event. Peripheral blood coagulation in patients with acute coronary thrombosis was compared with that in people with stable coronary artery disease (CAD). Blood coagulation and platelet activation at the microvascular injury site were assessed using immunochemistry in 28 non-anticoagulated patients with acute myocardial infarction (AMI) versus 28 stable CAD patients matched for age, sex, risk factors, and medications. AMI was associated with increased maximum rates of thrombin-antithrombin complex generation (by 93.8%; P < .001), thrombin B-chain formation (by 57.1%; P < .001), prothrombin consumption (by 27.9%; P = .012), fibrinogen consumption (by 27.0%; P = .02), factor (f) Va light chain generation (by 44.2%; P = .003), and accelerated fVa inactivation (by 76.1%; P < .001), and with enhanced release of platelet-derived soluble CD40 ligand (by 44.4%; P < .001). FVa heavy chain availability was similar in both groups because of enhanced formation and activated protein C (APC)–mediated destruction. The velocity of coagulant reactions in AMI patients showed positive correlations with interleukin-6. Heparin treatment led to dampening of coagulant reactions with profiles similar to those for stable CAD. AMI-induced systemic activation of blood coagulation markedly modifies the pattern of coagulant reactions at the site of injury in peripheral vessels compared with that in stable CAD patients. PMID:18931343

  5. Strongly Accelerated Margination of Active Particles in Blood Flow

    PubMed Central

    Gekle, Stephan

    2016-01-01

    Synthetic nanoparticles and other stiff objects injected into a blood vessel filled with red blood cells are known to marginate toward the vessel walls. By means of hydrodynamic lattice-Boltzmann simulations, we show that active particles can strongly accelerate their margination by moving against the flow direction: particles located initially in the channel center migrate much faster to their final position near the wall than in the nonactive case. We explain our findings by an enhanced rate of collisions between the stiff particles and the deformable red blood cells. Our results imply that a significantly faster margination can be achieved either technically by the application of an external magnetic field (if the particles are magnetic) or biologically by self-propulsion (if the particles are, e.g., swimming bacteria). PMID:26789773

  6. A comparative study of characteristics of current-type and conventional-type cationic bactericides.

    PubMed

    Ohta, S; Misawa, Y; Miyamoto, H; Makino, M; Nagai, K; Shiraishi, T; Nakagawa, Y; Yamato, S; Tachikawa, E; Zenda, H

    2001-09-01

    We have synthesized new polycationic bactericides, polyloxyethylene(dimethyliminio)trimethylene(dimethyliminio)ethylene dichloridel (OXD) and poly(hexamethyleneguanidine phosphate) (HEP), in order to develop more active but less skin-irritative bactericides. The effects of these bactericides on Pseudomonas aeruginosa, Escherichia coli, Serratia marcescens, Klebsiella pneumoniae, methicillin resistant Staphylococcus aureus (MRSA) and the degree of their irritations on skin were compared with those of a widely used low molecular-weight cationic bactericide, benzalkonium chloride (BAC), and a polycationic bactericide, poly[2-hydroxyethylene(dimethyliminio)methylene chloride] (2HYC). The minimum bactericidal concentration (MBC) of OXD for 10 min contact incubation was 16 microg/ml against P. aeruginosa, E. coli, S. marcescens and K. pneumoniae, and >1000 microg/ml against MRSA. The MBC of HEP for 10 min contact incubation was 16 microg/ml against P. aeruginosa, 32 microg/ml against E. coli and K. pneumoniae, and 64 microg/ml against S. marcescens and MRSA. Itch, edema, erythema, heat, injury, desquamation and keratinization caused by skin irritation were examined in 21 subjects by patch tests. Only one subject treated with OXD experienced edema, and one subject with HEP experienced keratinization. However, BAC caused itch in 3 subjects, edema in 1, erythema in 10 and desquamation in 2, indicating that the incidence of skin irritation of BAC was higher than that of OXD or HEP. OXD and HEP had sterilization ability similar to BAC, however, they were less skin-irritative than BAC. This indicates that OXD and HEP can be used as safe bactericides.

  7. Effect of porcine reproductive and respiratory syndrome virus (PRRSV) (isolate ATCC VR-2385) infection on bactericidal activity of porcine pulmonary intravascular macrophages (PIMs): in vitro comparisons with pulmonary alveolar macrophages (PAMs).

    PubMed

    Thanawongnuwech, R; Thacker, E L; Halbur, P G

    1997-11-01

    Porcine pulmonary intravascular macrophages (PIMs) were recovered by in situ pulmonary vascular perfusion with 0.025% collagenase in saline from six 8-week old, crossbred pigs. Pulmonary alveolar macrophages (PAMs) were recovered by bronchoalveolar lavage from the same pigs for comparisons in each assay. The macrophages were exposed to PRRSV (ATCC VR-2385) in vitro for 24 h and infection was confirmed by an indirect immunofluorescence test or transmission electron microscopy. Viral particles tended to accumulate in the vesicles of the Golgi apparatus or endoplasmic reticulum. Bactericidal function assays were performed on the recovered macrophages to determine the effects of the virus on macrophage functions. In vitro PRRSV infection reduced the bactericidal ability of PIMs from 68.3% to 56.4% (P < 0.09), and PAMs from 69.3% to 61.0% (P > 0.1) at 24 h post-infection. The mean percentage of bacteria killed by macrophages after PRRSV infection was not significantly different among the treatment groups or between the treatment groups and non-infected controls based on colorimetric MTT bactericidal (Staphylococcus aureus) assay. PRRSV did not affect the ability of PIMs or PAMs to internalize opsonized 125I-iododeoxyuridine-labeled S. aureus (P > 0.05). PRRSV infection significantly decreased the production of superoxide anion (P < 0.01) by 67.0% in PIMs and by 69.4% in PAMs. PRRSV reduced the myeloperoxidase-H2O2-halide product (P < 0.01) by 36.5% for PIMs and by 48.1% for PAMs. The results suggest: (1) PIMs should be considered as an important replication site of PRRSV; (2) PRRSV may have a detrimental effect on both PIMs and PAMs; (3) loss of bactericidal function in PIMs may facilitate hematogenous bacterial infections.

  8. Cord blood banking activity in Iran National Cord Blood Bank: a two years experience.

    PubMed

    Jamali, Mostafa; Atarodi, Kamran; Nakhlestani, Mozhdeh; Abolghasemi, Hasan; Sadegh, Hosein; Faranoosh, Mohammad; Golzade, Khadije; Fadai, Razieh; Niknam, Fereshte; Zarif, Mahin Nikougoftar

    2014-02-01

    Today umbilical cord blood (UCB) has known as a commonly used source of hematopoietic stem cells for allogeneic transplantation and many cord blood banks have been established around the world for collection and cryopreservation of cord blood units. Herein, we describe our experience at Iran National Cord Blood Bank (INCBB) during 2 years of activity. From November 2010 to 2012, UCBs were collected from 5 hospitals in Tehran. All the collection, processing, testing, cryopreservation and storage procedures were done according to standard operation procedures. Total nucleated cells (TNC) count, viability test, CD34+ cell count, colony forming unit (CFU) assay, screening tests and HLA typing were done on all banked units. Within 3770 collected units, only 32.9% fulfilled banking criteria. The mean volume of units was 105.2 ml and after volume reduction the mean of TNC, viability, CD34+ cells and CFUs was 10.76×10(8), 95.2%, 2.99×10(6) and 7.1×10(5), respectively. One unit was transplanted at Dec 2012 to a 5-year old patient with five of six HLA compatibilities. In our country banking of UCB is new and high rate of hematopoietic stem cell transplants needs expanding CB banks capacity to find more matching units, optimization of methods and sharing experiences to improve biological characterization of units.

  9. 21 CFR 864.7140 - Activated whole blood clotting time tests.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Activated whole blood clotting time tests. 864....7140 Activated whole blood clotting time tests. (a) Identification. An activated whole blood clotting... pulmonary embolism by measuring the coagulation time of whole blood. (b) Classification. Class...

  10. 21 CFR 864.7140 - Activated whole blood clotting time tests.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Activated whole blood clotting time tests. 864....7140 Activated whole blood clotting time tests. (a) Identification. An activated whole blood clotting... pulmonary embolism by measuring the coagulation time of whole blood. (b) Classification. Class...

  11. 21 CFR 864.7140 - Activated whole blood clotting time tests.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Activated whole blood clotting time tests. 864....7140 Activated whole blood clotting time tests. (a) Identification. An activated whole blood clotting... pulmonary embolism by measuring the coagulation time of whole blood. (b) Classification. Class...

  12. 21 CFR 864.7140 - Activated whole blood clotting time tests.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Activated whole blood clotting time tests. 864....7140 Activated whole blood clotting time tests. (a) Identification. An activated whole blood clotting... pulmonary embolism by measuring the coagulation time of whole blood. (b) Classification. Class...

  13. 21 CFR 864.7140 - Activated whole blood clotting time tests.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Activated whole blood clotting time tests. 864....7140 Activated whole blood clotting time tests. (a) Identification. An activated whole blood clotting... pulmonary embolism by measuring the coagulation time of whole blood. (b) Classification. Class...

  14. Blood

    MedlinePlus

    ... that die or are lost from the body. White Blood Cells White blood cells (WBCs, and also ... of severe pain. previous continue Diseases of the White Blood Cells Neutropenia (pronounced: new-truh-PEE-nee- ...

  15. Synthesis and characterization of bactericidal silver nanoparticles using cultural filtrate of simulated microgravity grown Klebsiella pneumoniae.

    PubMed

    Kalpana, Duraisamy; Lee, Yang Soo

    2013-03-05

    Silver nanoparticles were synthesized by biological method using cultural filtrate of Klebsiella pneumoniae cultured under simulated microgravity and silver nitrate solution as precursor. The nanoparticles exhibited typical plasmon absorption maximum of silver nanoparticles between 405 and 407 nm. Spherical silver nanoparticles were found to have size between 15 and 37 nm by TEM analysis. XRD pattern corresponding to planes (111), (200), (220) (311) revealed the crystalline nature of the biosynthesized silver nanoparticles. FTIR spectrum proposed stabilization of silver nanoparticles by the protein molecules present in the cultural filtrate. The silver nanoparticles exhibited high bactericidal activity against Salmonella enterica, Escherichia coli and moderate bactericidal activity against Streptococcus pyogenes.

  16. Adrenergic and non-adrenergic control of active skeletal muscle blood flow: implications for blood pressure regulation during exercise.

    PubMed

    Holwerda, Seth W; Restaino, Robert M; Fadel, Paul J

    2015-03-01

    Blood flow to active skeletal muscle increases markedly during dynamic exercise. However, despite the massive capacity of skeletal muscle vasculature to dilate, arterial blood pressure is well maintained. Sympathetic nerve activity is elevated with increased intensity of dynamic exercise, and is essential for redistribution of cardiac output to active skeletal muscle and maintenance of arterial blood pressure. In addition, aside from the sympathetic nervous system, evidence from human studies is now emerging that supports roles for non-adrenergic vasoconstrictor pathways that become active during exercise and contribute to vasoconstriction in active skeletal muscle. Neuropeptide Y and adenosine triphosphate are neurotransmitters that are co-released with norepinephrine from sympathetic nerve terminals capable of producing vasoconstriction. Likewise, plasma concentrations of arginine vasopressin, angiotensin II (Ang II) and endothelin-1 (ET-1) increase during dynamic exercise, particularly at higher intensities. Ang II and ET-1 have both been shown to be important vasoconstrictor pathways for restraint of blood flow in active skeletal muscle and the maintenance of arterial blood pressure during exercise. Indeed, although both adrenergic and non-adrenergic vasoconstriction can be attenuated in exercising muscle with greater intensity of exercise, with the higher volume of blood flow, the active skeletal muscle vasculature remains capable of contributing importantly to the maintenance of blood pressure. In this brief review we provide an update on skeletal muscle blood flow regulation during exercise with an emphasis on adrenergic and non-adrenergic vasoconstrictor pathways and their potential capacity to offset vasodilation and aid in the regulation of blood pressure.

  17. Bactericidal Effects and Mechanism of Action of Olanexidine Gluconate, a New Antiseptic

    PubMed Central

    Iwata, Koushi; Nii, Takuya; Nakata, Hikaru; Tsubotani, Yoshie; Inoue, Yasuhide

    2015-01-01

    Olanexidine gluconate [1-(3,4-dichlorobenzyl)-5-octylbiguanide gluconate] (development code OPB-2045G) is a new monobiguanide compound with bactericidal activity. In this study, we assessed its spectrum of bactericidal activity and mechanism of action. The minimal bactericidal concentrations of the compound for 30-, 60-, and 180-s exposures were determined with the microdilution method using a neutralizer against 320 bacterial strains from culture collections and clinical isolates. Based on the results, the estimated bactericidal olanexidine concentrations with 180-s exposures were 869 μg/ml for Gram-positive cocci (155 strains), 109 μg/ml for Gram-positive bacilli (29 strains), and 434 μg/ml for Gram-negative bacteria (136 strains). Olanexidine was active against a wide range of bacteria, especially Gram-positive cocci, including methicillin-resistant Staphylococcus aureus and vancomycin-resistant enterococci, and had a spectrum of bactericidal activity comparable to that of commercial antiseptics, such as chlorhexidine and povidone-iodine. In vitro experiments exploring its mechanism of action indicated that olanexidine (i) interacts with the bacterial surface molecules, such as lipopolysaccharide and lipoteichoic acid, (ii) disrupts the cell membranes of liposomes, which are artificial bacterial membrane models, (iii) enhances the membrane permeability of Escherichia coli, (iv) disrupts the membrane integrity of S. aureus, and (v) denatures proteins at relatively high concentrations (≥160 μg/ml). These results indicate that olanexidine probably binds to the cell membrane, disrupts membrane integrity, and its bacteriostatic and bactericidal effects are caused by irreversible leakage of intracellular components. At relatively high concentrations, olanexidine aggregates cells by denaturing proteins. This mechanism differs slightly from that of a similar biguanide compound, chlorhexidine. PMID:25987609

  18. Chemotactic and Phagocytic Activity of Blood Neutrophils in Allergic Asthma.

    PubMed

    Mosca, Tainá; Menezes, Maria C S; Silva, Ademir Veras; Stirbulov, Roberto; Forte, Wilma C N

    2015-01-01

    Allergic asthma is a chronic inflammatory airway disease, and has been considered a T helper-2-biased response. Studies suggest that neutrophils may be associated with exacerbation and asthma severity. We sought to evaluate the chemotactic activity and phagocytic capacity by peripheral blood neutrophils from individuals with controlled and uncontrolled allergic asthma, and compare the results with non-asthmatic controls groups. Blood neutrophils were isolated from 95 patients: 24 with controlled asthma, 24 uncontrolled asthma, 24 healthy subjects and 23 patients with IgE-mediated allergies other than asthma. The neutrophil chemotaxis, stimulated with LPS, autologous serum or homologous serum, was determined using Boyden chambers. The phagocytic capacity was assessed by ingestion of zimosan particles, and digestion phase was analyzed by NBT test. The phagocytic digestion phase and chemotaxis by neutrophils from asthmatic patients was higher than in non-asthmatic controls (p  < 0.05). Autologous serum-induced neutrophil chemotaxis in patients with uncontrolled asthma was greater (p  < 0.05) than in other study groups. The ingestion phase of phagocytosis showed similar values in asthmatics and non-asthmatics. We conclude that the blood neutrophil from controlled and uncontrolled asthmatic patients exhibit activation markers, particularly phagocytic digestion and chemotactic activities.

  19. Following the mechanisms of bacteriostatic versus bactericidal action using Raman spectroscopy.

    PubMed

    Bernatová, Silvie; Samek, Ota; Pilát, Zdeněk; Serý, Mojmír; Ježek, Jan; Jákl, Petr; Siler, Martin; Krzyžánek, Vladislav; Zemánek, Pavel; Holá, Veronika; Dvořáčková, Milada; Růžička, Filip

    2013-10-24

    Antibiotics cure infections by influencing bacterial growth or viability. Antibiotics can be divided to two groups on the basis of their effect on microbial cells through two main mechanisms, which are either bactericidal or bacteriostatic. Bactericidal antibiotics kill the bacteria and bacteriostatic antibiotics suppress the growth of bacteria (keep them in the stationary phase of growth). One of many factors to predict a favorable clinical outcome of the potential action of antimicrobial chemicals may be provided using in vitro bactericidal/bacteriostatic data (e.g., minimum inhibitory concentrations-MICs). Consequently, MICs are used in clinical situations mainly to confirm resistance, and to determine the in vitro activities of new antimicrobials. We report on the combination of data obtained from MICs with information on microorganisms' "fingerprint" (e.g., DNA/RNA, and proteins) provided by Raman spectroscopy. Thus, we could follow mechanisms of the bacteriostatic versus bactericidal action simply by detecting the Raman bands corresponding to DNA. The Raman spectra of Staphylococcus epidermidis treated with clindamycin (a bacteriostatic agent) indeed show little effect on DNA which is in contrast with the action of ciprofloxacin (a bactericidal agent), where the Raman spectra show a decrease in strength of the signal assigned to DNA, suggesting DNA fragmentation.

  20. Bactericidal behavior of Cu-containing stainless steel surfaces

    NASA Astrophysics Data System (ADS)

    Zhang, Xiangyu; Huang, Xiaobo; Ma, Yong; Lin, Naiming; Fan, Ailan; Tang, Bin

    2012-10-01

    Stainless steels are one of the most common materials used in health care environments. However, the lack of antibacterial advantage has limited their use in practical application. In this paper, antibacterial stainless steel surfaces with different Cu contents have been prepared by plasma surface alloying technology (PSAT). The steel surface with Cu content 90 wt.% (Cu-SS) exhibits strong bactericidal activity against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) within 3 h. Although the Cu-containing surface with Cu content 2.5 wt.% (CuNi-SS) can also kill all tested bacteria, this process needs 12 h. SEM observation of the bacterial morphology and an agarose gel electrophoresis were performed to study the antibacterial mechanism of Cu-containing stainless steel surfaces against E. coli. The results indicated that Cu ions are released when the Cu-containing surfaces are in contact with bacterial and disrupt the cell membranes, killing the bacteria. The toxicity of Cu-alloyed surfaces does not cause damage to the bacterial DNA. These results provide a scientific explanation for the antimicrobial applications of Cu-containing stainless steel. The surfaces with different antibacterial abilities could be used as hygienic surfaces in healthcare-associated settings according to the diverse requirement of bactericidal activities.

  1. Human blood platelets lack nitric oxide synthase activity.

    PubMed

    Böhmer, Anke; Gambaryan, Stepan; Tsikas, Dimitrios

    2015-01-01

    Reports on expression and functionality of nitric oxide synthase (NOS) activity in human blood platelets and erythrocytes are contradictory. We used a specific gas chromatography-mass spectrometry (GC-MS) method to detect NOS activity in human platelets. The method measures simultaneously [(15)N]nitrite and [(15)N]nitrate formed from oxidized (15)N-labeled nitric oxide ((15)NO) upon its NOS-catalyzed formation from the substrate l-[guanidino-(15)N2]-arginine. Using this GC-MS assay, we did not detect functional NOS in non-stimulated platelets and in intact platelets activated by various agonists (adenosine diphosphate, collagen, thrombin, or von Willebrand factor) or lysed platelets. l-[guanidino-nitro]-Arginine-inhibitable NOS activity was measured after addition of recombinant human endothelial NOS to lysed platelets. Previous and recent studies from our group challenge expression and functionality of NOS in human platelets and erythrocytes.

  2. Blood coagulation activation and fibrinolysis during a downhill marathon run.

    PubMed

    Sumann, Günther; Fries, Dietmar; Griesmacher, Andrea; Falkensammer, Gerda; Klingler, Anton; Koller, Arnold; Streif, Werner; Greie, Sven; Schobersberger, Beatrix; Schobersberger, Wolfgang

    2007-07-01

    Prolonged physical exercise is associated with multiple changes in blood hemostasis. Eccentric muscle activation induces microtrauma of skeletal muscles, inducing an inflammatory response. Since there is a link between inflammation and coagulation we speculated that downhill running strongly activates the coagulation system. Thirteen volunteers participated in the Tyrolean Speed Marathon (42,195 m downhill race, 795 m vertical distance). Venous blood was collected 3 days (T1) and 3 h (T2) before the run, within 30 min after finishing (T3) and 1 day thereafter (T4). We measured the following key parameters: creatine kinase, myoglobin, thrombin-antithrombin complex, prothrombin fragment F1 + 2, D-dimer, plasmin-alpha(2)-antiplasmin complexes, tissue-type plasminogen activator antigen, plasminogen-activator-inhibitor-1 antigen and thrombelastography with ROTEM [intrinsic pathway (InTEM) clotting time, clot formation time, maximum clot firmness, alpha angle]. Thrombin generation was evaluated by the Thrombin Dynamic Test and the Technothrombin TGA test. Creatine kinase and myoglobin were elevated at T3 and further increased at T4. Thrombin-antithrombin complex, prothrombin fragment F1 + 2, D-dimer, plasmin-alpha(2)-antiplasmin complexes, tissue-type plasminogen activator antigen and plasminogen-activator-inhibitor-1 antigen were significantly increased at T3. ROTEM analysis exhibited a shortening of InTEM clotting time and clot formation time after the marathon, and an increase in InTEM maximum clot firmness and alpha angle. Changes in TGA were indicative for thrombin generation after the marathon. We demonstrated that a downhill marathon induces an activation of coagulation, as measured by specific parameters for coagulation, ROTEM and thrombin generation assays. These changes were paralleled by an activation of fibrinolysis indicating a preserved hemostatic balance.

  3. Procoagulant activity in stored units of red blood cells.

    PubMed

    Aleshnick, Maya; Foley, Jonathan H; Keating, Friederike K; Butenas, Saulius

    2016-06-10

    The procoagulant activity (PA) of stored units of red blood cells (RBC) increases over time, which is related to the expression/exposure of tissue factor (TF). However, there is a discrepancy between the TF measured and changes in PA observed, suggesting that other blood components contribute to this activity. Our goal was to evaluate changes in PA of stored RBCs and to determine possible contributors to it. RBC units from 4 healthy donors were prepared and stored at 4 °C. On selected days, RBC aliquots were reconstituted with autologous plasma and tested in the thromboelastography assay. Corresponding supernatants were tested in a clotting assay. For all donors, the clotting time (CT) of reconstituted RBC units decreased from ∼3000-4000s on day 1 to ∼1000-1600s on day 30, with the most dramatic changes occurring between days 1 and 5. Anti-TF antibody slightly prolonged the CT. The concentration of TF did not change significantly over time and was within the range of 0.3-2.3 pM. Bovine lactadherin (LTD) prolonged the CT of the RBC (by 2.4-3.4-fold in days 3-5 and by 1.3-1.8-fold at day 30). Anti-TF antibody together with LTD had a cumulative effect on the CT prolongation. CT of supernatants responded to both anti-TF and anti-FXIa antibodies. Three contributors to the PA of stored RBC were identified, i.e. FXIa in solution and phosphatidylserine and TF exposed on blood cells and microparticles. Failure of LTD and antibodies to completely eliminate PA suggests that other components of blood could contribute to it.

  4. Serum Bactericidal Assay: New Role in Salmonella Detection.

    PubMed

    Chen, Yu; Wu, Da; Sun, Min; Deng, Mingjun; Cui, Shuhua; Liang, Chengzhu; Geng, Juan; Sun, Tao; Long, Ling; Xiao, Xizhi

    2016-01-01

    While inspecting animal feed for Salmonella contamination, we routinely observed bacterial colonies on selective agars that were similar in appearance to those formed by Salmonella. These were identified as Citrobacter freundii, Proteus mirabilis, and Serratia fonticola using biochemical and serological techniques. Because the presence of these bacterial species confounds identification of Salmonella, we refer to them as "interference bacteria." Polyvalent antisera against these interference bacteria were prepared by immunizing rabbits with a mixture of all three organisms. To minimize or eliminate interference by these bacteria, the polyvalent antisera were introduced between the steps of selective enrichment and Salmonella-selective plating. The antisera raised against the interference bacteria, when combined with neonatal rabbit complement, exhibited specific bactericidal activity against C. freundii, P. mirabilis, and S. fonticola. The respective serum bactericidal assay titers were 2(9), 2(8), and 2(10). In selective broth, polyvalent antisera could also kill the target bacterial cells effectively. We tested 526 samples (186 white fishmeal, 97 red fishmeal, and 243 cattle bone powder) using the polyvalent antisera and found that the rates of contamination of each species of the three respective foods decreased by 58.8, 100, and 83%. Our data indicates that polyvalent sera against C. freundii, P. mirabilis, and S. fonticola can be used as inhibitors to increase the accuracy of Salmonella detection.

  5. Enhanced Cholinergic Activity Improves Cerebral Blood Flow during Orthostatic Stress

    PubMed Central

    Serrador, Jorge M.; Freeman, Roy

    2017-01-01

    Cerebral blood flow (CBF) and consequently orthostatic tolerance when upright depends on dilation of the cerebral vasculature in the face of reduced perfusion pressure associated with the hydrostatic gradient. However, it is still unclear if cholinergic activation plays a role in this dilation. To determine if enhancing central cholinergic activity with the centrally acting acetylcholinesterase inhibitor, physostigmine would increase CBF when upright compared to the peripherally acting acetylcholinesterase inhibitor, neostigmine, or saline. We performed a randomized double-blind dose-ranging study that took place over 3 days in a hospital-based research lab. Eight healthy controls (six women and two men, mean age, 26 years; range 21–33) were given infusions of physostigmine, neostigmine, or saline on three different days. Five-minute tilts were repeated at baseline (no infusion), Dose 1 (0.2 μg/kg/min physostigmine; 0.1 μg/kg/min neostigmine) and Dose 2 (0.6 μg/kg/min physostigmine or 0.3 μg/kg/min neostigmine), and placebo (0.9% NaCl). Cerebral blood velocity, beat-to-beat blood pressure, and end-tidal CO2 were continuously measured during tilts. Physostigmine (0.6 μg/kg/min) resulted in higher cerebral blood velocity during tilt (90.5 ± 1.5%) than the equivalent neostigmine (85.5 ± 2.6%) or saline (84.8 ± 1.7%) trials (P < 0.05). This increase occurred despite a greater postural hypocapnia, suggesting physostigmine had a direct vasodilatory effect on the cerebral vasculature. Cerebral hypoperfusion induced by repeated tilts was eliminated by infusion of physostigmine not neostigmine. In conclusion, this study provides the first evidence that enhancement of central, not peripheral, cholinergic activity attenuates the physiological decrease in CBF seen during upright tilt. These data support the need for further research to determine if enhancing central cholinergic activity may improve symptoms in patients with symptomatic

  6. The relationship of electronically monitored physical activity to blood pressure, heart rate, and the circadian blood pressure profile.

    PubMed

    Mansoor, G A; White, W B; McCabe, E J; Giacco, S

    2000-03-01

    We studied how closely changes in electronically monitored physical activity are reflected in changes in blood pressure and heart rate in a group of untreated hypertensive subjects. Thirty-nine hypertensive patients (office blood pressure > 140/ 90 mm Hg) of mean age 57 +/- 10 years (mean +/-SD) wore an ambulatory blood pressure monitor and a wrist actigraph simultaneously. Both average and peak activity for 5 min before each valid blood pressure reading were determined, as was average activity for awake and sleep periods, determined by patient kept diaries. For the overall group, awake and 24-h activities were inversely correlated to age (n = 39, r = -0.42; P = 0.01 and n = 39, r = -0.38; P = 0.01, respectively). No correlation was found between group awake activity and group-average blood pressure or heart rate. For individual patients, there was marked variation in the degree of correlation between awake activity measures (both peak and average) and blood pressure and heart rate. The strongest positive correlation was between activity levels and the heart rate-pressure product. Nondipper profile hypertensives had higher sleep activity than dipper hypertensives (44 +/- 28 units/min v 25 +/- 20 units/min, df = 37, t = 2.12; P = 0.04), but awake activity levels were similar. The higher sleep activity remained after adjustment for age. These findings indicate that the relationship between actigraphic activity and hemodynamic parameters is highly variable and that the rate-pressure product is the strongest correlate of short-term activity. Furthermore, hypertensives with the nondipper profile have higher sleep activity than dipper hypertensives. These findings stress the need for further study into the role of day-to-day activity in determining ambulatory blood pressure and heart rate variability.

  7. Bactericidal Action of Photo-Irradiated Aqueous Extracts from the Residue of Crushed Grapes from Winemaking.

    PubMed

    Tsukada, Mana; Sheng, Hong; Tada, Mika; Mokudai, Takayuki; Oizumi, Satomi; Kamachi, Toshiaki; Niwano, Yoshimi

    2016-01-01

    Our previous studies revealed that photo-irradiation of polyphenols could exert bactericidal action via reactive oxygen species (ROS). In the present study, the photo-irradiation-induced bactericidal activity of the aqueous extract from the residue of crushed grapes from winemaking was investigated in relation to ROS formation. Staphylococcus aureus suspended in the extract was irradiated with LED light at 400 nm. This solution killed the bacteria, and a 3-4 log and a >5-log reduction of the viable counts were observed within 10 and 20 min, respectively. LED light irradiation alone also killed the bacteria, but the viable counts were 2-4 log higher than those of the photo-irradiated extract. In contrast, almost no change occurred in the suspension without LED irradiation. When hydroxyl radical scavengers were added to the suspension, the bactericidal effect of the photo-irradiated extract was attenuated. Furthermore, electron spin resonance analysis demonstrated that hydroxyl radicals were generated by the photo-irradiation of the extract. The present study suggests that polyphenolic compounds in the extract exert bactericidal activity via hydroxyl radical formation upon photo-irradiation.

  8. Preparation of highly dispersed MgO and its bactericidal properties

    NASA Astrophysics Data System (ADS)

    Huang, L.; Li, D.-Q.; Evans, D. G.; Duan, X.

    2005-07-01

    Samples of layered double hydroxides (LDHs) were prepared by a method involving separate nucleation and aging steps recently developed in our laboratory, using varying [ Mg2+] /[ Al3+] ratios and different aging conditions. The samples were characterized by X-ray diffraction (XRD), FT-IR spectroscopy and laser granulometry. The results showed that LDHs with different particle sizes could be obtained by controlling the reaction temperature and degree of supersaturation. Calcination of these materials affords mixtures of highly dispersed MgO and mixed metal oxides. Bactericidal experiments against Bacillus subtilis var. niger and Staphylococcus aureus were carried out using materials formed by calcination of the LDHs at 500 circC. The mechanism of bactericidal activity was also investigated. It is known that MgO is very readily hydrated and that reaction with dissolved oxygen affords superoxide anions O{2}-, which attack the secondary amide structure of proteins leading to destruction of the bacteria. The bactericidal activity of the MgO increases with specific surface area because this leads to an increased number of surface hydroxyl groups and higher concentrations of O{2}- in solution. The bactericidal ability of MgO therefore increases with decreasing particle size.

  9. Rotavirus activates dendritic cells derived from umbilical cord blood monocytes.

    PubMed

    Rosales-Martinez, D; Gutierrez-Xicotencatl, L; Badillo-Godinez, O; Lopez-Guerrero, D; Santana-Calderon, A; Cortez-Gomez, R; Ramirez-Pliego, O; Esquivel-Guadarrama, F

    2016-10-01

    Rotavirus is the most common cause of acute infectious diarrhea in human neonates and infants. However, the studies aimed at dissecting the anti-virus immune response have been mainly performed in adults. Dendritic cells (DCs) play a crucial role in innate and acquired immune responses. Therefore, it is very important to determine the response of neonatal and infant DCs to rotavirus and to compare it to the response of adult DCs. Thus, we determined the response of monocyte-derived DCs from umbilical cord blood (UCB) and adult peripheral blood (PB) to rotavirus in vitro. It was found that the rotavirus and its genome, composed of segmented doubled stranded RNA (dsRNA), induced the activation of neonatal DCs, as these cells up-regulated the levels of CD40, CD86, MHC II, TLR-3 and TLR-4, the production of cytokines IL-6, IL-12/23p40, IL-10, TGF-β (but not of IL-12p70), and the message for TNF-α and IFN-β. This activation enabled the neonatal DCs to induce a strong proliferation of allogeneic CD4(+) T cells and the production of IFN-γ. Moreover, neonatal DCs could be infected by rotavirus and sustain its replication. Neonatal DCs had a similar response as adult DCs towards rotavirus and its genome. However, adult DCs had a biased pro-inflammatory response compared to neonatal DCs, which showed a biased regulatory profile, as they produced higher levels of IL-10 and TGF-β, and were less efficient in inducing a Th1 type response. So it can be concluded that rotavirus and its genome can induce the activation of neonatal DCs in spite of their tolerogenic bias.

  10. Integrated antifouling and bactericidal polymer membranes through bioinspired polydopamine/poly(N-vinyl pyrrolidone) coating

    NASA Astrophysics Data System (ADS)

    Wang, Xianghong; Yuan, Shuaishuai; Shi, Dean; Yang, Yingkui; Jiang, Tao; Yan, Shunjie; Shi, Hengchong; Luan, Shifang; Yin, Jinghua

    2016-07-01

    Polypropylene (PP) non-woven has been widely used as wound dressing; however, the hydrophobic nature of PP can initiate bacterial attachment and subsequent biofilm formation. Herein, we propose a facile approach to functionalize PP non-woven with poly(ethylene glycol) (PEG) and poly(N-vinyl pyrrolidone)-iodine complex (PVP-I). PVP and PEG were successively tethered onto PP non-woven surface via versatile bioinspired dopamine (DA) chemistry, followed by complexing iodine with PVP moieties. It was demonstrated through the field emission scanning electron microscope (SEM) and spread plate method that the as-modified PP non-woven integrated both antifouling property of PEG for suppressing bacterial adhesion, and bactericidal property of PVP-I for killing the few adherent bacteria. Meanwhile, it could greatly resist platelet and red blood cell adhesion. The integrated antifouling and bactericidal PP non-woven surfaces might have great potential in various wound dressing applications.

  11. Pleasant Events, Activity Restriction, and Blood Pressure in Dementia Caregivers

    PubMed Central

    Chattillion, Elizabeth A.; Ceglowski, Jenni; Roepke, Susan K.; von Känel, Roland; Losada, Andres; Mills, Paul J.; Romero-Moreno, Rosa; Grant, Igor; Patterson, Thomas L.; Mausbach, Brent T.

    2012-01-01

    Objective A combination of high engagement in pleasurable activities and low perceived activity restriction is potentially protective for a number of health and quality of life outcomes. This study tests the newly proposed Pleasant Events and Activity Restriction (PEAR) model to explain level of blood pressure (BP) in a sample of elderly dementia caregivers. Methods This cross-sectional study included 66 caregivers, ≥ 55 years of age, providing in-home care to a relative with dementia. Planned comparisons were made to assess group differences in BP between caregivers reporting high engagement in pleasant events plus low perceived activity restriction (HPLR; N = 22) to those with low pleasure plus high restriction (LPHR; N = 23) or those with either high pleasure plus high restriction or low pleasure plus low restriction (HPHR/LPLR; N = 21). Results After adjustments for age, sex, body mass index, use of anti-hypertensive medication, physical activity, and number of health problems, HPLR participants (86.78 mm Hg) had significantly lower mean arterial pressure compared to LPHR participants (94.70 mm Hg) (p = .01, Cohen’s d=0.89) and HPHR/LPLR participants (94.84 mm Hg) (p = .023, d=0.91). Similar results were found in post-hoc comparisons of both systolic and diastolic BP. Conclusions This study extends support for the PEAR model to physical health outcomes. Differences in BP between the HPLR group and other groups were of large magnitude and thus clinically meaningful. The findings may inform intervention studies aimed at investigating whether increasing pleasant events and lowering perceived activity restriction may lower BP. PMID:22888824

  12. Determination of phosphodiesterase I activity in human blood serum.

    PubMed

    Hynie, I; Meuffels, M; Poznanski, W J

    1975-09-01

    Phosphodiesterase I (EC 3.1.4.1) activity was detected in normal human blood serum. The enzyme is stable at laboratory temperature for three days, but is inactivated at pH less than 7. The pH for optimum activity increases with the substrate concentration (under the conditions used, from pH 9.0 to 10.2) and, conversely, the Km increases with pH and buffer concentration. The enzyme is inhibited by ethylenediaminetetraacetate but not by phosphate (0.1 mol/liter). We developed a simple quantitative method for its determination, based on hydrolysis of the p-nitrophenyl ester of thymidine 5'-monophosphate and subsequent measurement of the liberated p-nitrophenol at 400 nm in NaOH (0.1 mol/liter). Normal values (mean +/- 2 SD) were determined to be 33 +/- 6.4 U/liter. Preliminary studies indicate that phosphodiesterase I activity is greater than normal in serum of patients with necrotic changes in the liver or kidney or in cases of breast cancer, but not in that of patients with myocardial infarction, bone cancer, lung cancer, or chronic liver cirrhosis.

  13. Klebsiella species: antimicrobial susceptibilities, bactericidal kinetics, and in vitro inactivation of beta-lactam agents.

    PubMed Central

    Panwalker, A P; Trager, G M; Porembski, P E

    1980-01-01

    In vitro properties of 19 antimicrobial agents were tested with 56 isolates of Klebsiella spp. The aminoglycosides and the new beta-lactam compounds cefotaxime and moxalactam were the most inhibitory drugs tested. Chloramphenicol, tetracycline, trimethoprim, and trimethoprim-sulfamethoxazole were moderately active, whereas piperacillin, mezlocillin, and furazlocillin were ineffective against 25% of the isolates. Gentamicin was the only agent tested that was uniformly bactericidal in time-kill experiments with drug concentrations of four times the minimal inhibitory concentration. In combination studies with gentamicin, moxalactam and furazlocillin each increased the rate of bacterial killing for three of five isolates as compared with gentamicin alone, whereas chloramphenicol significantly retarded the rate of bacterial killing for the same number of strains. Furazlocillin was completely inactivated after 24 h of incubation with each of five selected strains. The inactivation of moxalactam, cefoxitin, and cephalothin was 36, 56, and 72%, respectively. In all instances in which these four agents were inactivated to levels below the minimal bactericidal concentration, there was accelerated growth after initial inhibition. However, regrowth also occurred in three instances in which drug levels were higher than the minimal bactericidal concentration. Retesting after drug exposure revealed a 4- to 32-fold rise in the minimal inhibitory concentration and minimal bactericidal concentration in two of these isolates. PMID:7235676

  14. Residual water bactericide monitor development program

    NASA Technical Reports Server (NTRS)

    1973-01-01

    A silver-ion bactericidal monitor is considered for the Space Shuttle Potable Water System. Potentiometric measurement using an ion-selective electrode is concluded to be the most feasible of available techniques. Four commercially available electrodes and a specially designed, solid-state, silver-sulfide electrode were evaluated for their response characteristics and suitability for space use. The configuration of the solid-state electrode with its Nernstian response of 10 to 10,000 ppb silver shows promise for use in space. A pressurized double-junction reference electrode with a quartz-fiber junction and a replaceable bellows electrolyte reservoir was designed verification-tested, and paired with a solid-state silver-sulfide electrode in a test fixture.

  15. Blood plasma contact activation on silicon, titanium and aluminium.

    PubMed

    Arvidsson, Sara; Askendal, Agneta; Tengvall, Pentti

    2007-03-01

    In the present work, blood plasma protein deposition to spontaneously air oxidized silicon, titanium and aluminium was re-investigated in vitro. Immunological- and null ellipsometry methods were used to detect and quantitate adsorbed proteins, RIA methods to study the retention of preadsorbed 125I-HSA upon exposure to buffer or blood plasma, and kallikrein-specific colorimetric substrate S-2302 to follow the surface generation of kallikrein. The results show that the contact activation of coagulation and complement systems are connected on Si and Ti, but not on Al, via coagulation factor XII. Preadsorbed 125I-HSA was most readily displaced on silicon, followed by titanium and aluminium. The surfaces displayed different antibody binding patterns after short and long-time exposures to plasma. Titanium and silicon bound anti-HMWK after 1 min in plasma, but aluminium did not. When the plasma incubation time was prolonged up to 2h the anti-HMWK binding disappeared totally on titanium and decreased on silicon. During the same time period, anti-C3c binding increased to the three types of surfaces. Also, the anti-C3c binding onto Si and Ti, but not Al, disappeared after incubation in Factor XII deficient plasma or when a specific coagulation factor XII (Factor XII) inhibitor, corn trypsin inhibitor (CTI) was added to normal plasma. The surface contacted plasmas cleaved the kallikrein-specific reagent S-2302 both after single surface contact, and after reincubation of surfaces in fresh plasma. The results show that C3b and Factor XIIa and their degradation products were retained at the surfaces.

  16. The bactericidal effect on Pseudomonas strains of adriamycin associated with quinolones.

    PubMed

    Castelli, M; Baggio, G; Aresca, P; Bossa, R; Galatulas, I

    1989-01-01

    The in vitro antibacterial activity of quinolone compounds was assessed on strains of Pseudomonas aeruginosa isolated from clinical infections. The bactericidal effect of quinolones was high and their respective antibacterial properties with adriamycin remained unimpaired on strains both sensitive and resistant to betalactam and aminoglycoside antibiotics. The cytotoxic effect of the combination of adriamycin and quinolones was determined in cultured P388 leukemia cells: no interference with the cytotoxic activity of adriamycin was observed.

  17. Salmonella porins induce a sustained, lifelong specific bactericidal antibody memory response

    PubMed Central

    Secundino, Ismael; López-Macías, Constantino; Cervantes-Barragán, Luisa; Gil-Cruz, Cristina; Ríos-Sarabia, Nora; Pastelin-Palacios, Rodolfo; Angel Villasis-Keever, Miguel; Becker, Ingeborg; Luis Puente, José; Calva, Edmundo; Isibasi, Armando

    2006-01-01

    We examined the ability of porins from Salmonella enterica serovar typhi to induce a long-term antibody response in BALB/c mice. These porins triggered a strong lifelong production of immunoglobulin G (IgG) antibody in the absence of exogenous adjuvant. Analysis of the IgG subclasses produced during this antibody response revealed the presence of the subclasses IgG2b, IgG1, IgG2a and weak IgG3. Despite the high homology of porins, the long-lasting anti-S. typhi porin sera did not cross-react with S. typhimurium. Notably, the antiporin sera showed a sustained lifelong bactericidal-binding activity to the wild-type S. typhi strain, whereas porin-specific antibody titres measured by enzyme-linked immunosorbent assay (ELISA) decreased with time. Because our porin preparations contained the outer membrane proteins C and F (OmpC and OmpF), we evaluated the individual contribution of each porin to the long-lasting antibody response. OmpC and OmpF induced long-lasting antibody titres, measured by ELISA, which were sustained for 300 days. In contrast, although OmpC induced sustained high bactericidal antibody titres for 300 days, postimmunization, the bactericidal antibody titre induced by OmpF was not detected at day 180. These results indicate that OmpC is the main protein responsible for the antibody-mediated memory bactericidal response induced by porins. Taken together, our results show that porins are strong immunogens that confer lifelong specific bactericidal antibody responses in the absence of added adjuvant. PMID:16423041

  18. Characterization of the extracellular bactericidal factors of rat alveolar lining material.

    PubMed Central

    Coonrod, J D; Lester, R L; Hsu, L C

    1984-01-01

    The surfactant fraction (55,000-g pellet) of leukocyte-free rat bronchoalveolar lavage fluid contains factors that rapidly kill and lyse pneumococci. These factors were purified and identified biochemically by using a quantitative bactericidal test to monitor fractionation procedures. 91% of the antipneumococcal activity of rat surfactant was recovered in chloroform after extraction of rat surfactant with chloroform-methanol (Bligh-Dyer procedure). After chromatography on silicic acid with chloroform, acetone, and methanol, all detectable antibacterial activity (approximately 80% of the initial activity) eluted with the neutral lipids in chloroform. When rechromatographed on silicic acid with hexane, hexane-chloroform, and chloroform, the antibacterial activity eluted with FFA. Thin-layer chromatography (TLC) established that the antibacterial activity was confined to the FFA fraction. Gas-liquid chromatography showed that the fatty acid fraction contained a mixture of long-chain FFA (C12 to C22) of which 66.7% were saturated and 32.4% were unsaturated. The quantity of TLC-purified FFA needed to kill 50% of 10(8) pneumococci under standardized conditions (one bactericidal unit) was 10.6 +/- 0.5 micrograms. Purified FFA acted as detergents, causing release of [3H]choline from pneumococcal cell walls and increased bacterial cell membrane permeability, evidenced by rapid unloading of 3-O-[3H]methyl-D-glucose. FFA acting as detergents appear to account for the bactericidal and bacteriolytic activity of rat pulmonary surfactant for pneumococci. PMID:6548228

  19. Highly Bactericidal Polyurethane Effective Against Both Normal and Drug-Resistant Bacteria: Potential Use as an Air Filter Coating.

    PubMed

    Taylor, Matthew; McCollister, Bruce; Park, Daewon

    2016-03-01

    The battle against the prevalence of hospital-acquired infections has underscored the importance of identifying and maintaining the cleanliness of possible infection transmission sources in the patient's environment. One of the most crucial lines of defense for mitigating the spread of pathogens in a healthcare facility is the removal of microorganisms from the environment by air filtration systems. After removing the pathogenic microorganisms, the filters used in these systems can serve as reservoirs for the pathogens and pose a risk for secondary infection. This threat, combined with the ever-growing prevalence of drug-resistant bacterial strains, substantiates the need for an effective bactericidal air filter. To this end, a broad-spectrum bactericidal polyurethane incorporating immobilized quaternary ammonium groups was developed for use as an air filter coating. In this study, the bactericidal activity of the polymer coating on high-efficiency particulate air (HEPA) filter samples was quantified against eight bacterial strains commonly responsible for nosocomial infection-including drug-resistant strains, and confirmed when applied as a filter coating in conditions mimicking those of its intended application. The coated HEPA filter samples exhibited high bactericidal activity against all eight strains, and the polyurethane was concluded to be an effective coating in rendering HEPA filters bactericidal.

  20. Voltage-activated proton current in eosinophils from human blood.

    PubMed Central

    Gordienko, D V; Tare, M; Parveen, S; Fenech, C J; Robinson, C; Bolton, T B

    1996-01-01

    negative potentials and enhancement of maximum conductance (gH,max). The proton current recorded in eosinophils was significantly augmented under conditions of elevated cytosolic free calcium concentration ([Ca2+]i). The threshold level of [Ca2+]i associated with this effect lay between 0.1 and 1 microM and was not measurably affected by cytosolic acidification. 7. Eosinophils from human blood possess a voltage-dependent H+ conductance (gH) which normally allows protons to move outwards only; raising [Ca2+]i was associated with augmentation of gH and intracellular acidification or arachidonate shifted its activation range negatively towards physiological potentials. PMID:8910217

  1. ABO/Rh Blood-Typing Model: A Problem-Solving Activity

    ERIC Educational Resources Information Center

    Wake, Carol

    2005-01-01

    An ARO/Rh Blood-Typing kit useful for students to visualize blood-typing activities and practice problem-solving skills with transfusion reactions is presented. The model also enables students to identify relationships between A, B, and Rh antigens and antibodies in blood and to understand molecular mechanisms involved in transfusion agglutination…

  2. [Age-related changes in blood plasma antioxidant activity in population of the southern Altai].

    PubMed

    Chanchaev, E A; Aĭzman, R I

    2012-01-01

    The blood plasma antioxidant activity was studied in the Russian and Kazakh aborigines of the southern Altai low and high mountains. There was established a decrease of the blood plasma antioxidant activity with age and a relatively low plasma antioxidant activity in the mid-mountain population; in its senior age groups, the gender differences of this parameter were revealed.

  3. Blood

    MedlinePlus

    ... increased red blood cell destruction can affect teens: G6PD deficiency. G6PD is an enzyme that helps to protect ... can cause red cells to hemolyze, or burst. G6PD deficiency is a common hereditary disease among people of ...

  4. Silver ion bactericide system. [for Space Shuttle Orbiter potable water

    NASA Technical Reports Server (NTRS)

    Jasionowski, W. J.; Allen, E. T.

    1974-01-01

    Description of a preliminary flight prototype system which uses silver ions as the bactericide to preserve sterility of the water used for human consumption and hygiene in the Space Shuttle Orbiter. The performance of silver halide columns for passively dosing fuel cell water with silver ions is evaluated. Tests under simulated Orbiter mission conditions show that silver ion doses of 0.05 ppm are bactericidal for Pseudomonas aeruginosa and Type IIIa, the two bacteria found in Apollo potable water systems. The design of the Advance Prototype Silver Ion Water Bactericide System now under development is discussed.

  5. Blood pressure reduction following accumulated physical activity in prehypertensive

    PubMed Central

    Saxena, Yogesh; Gupta, Rani; Moinuddin, Arsalan; Narwal, Ravinder

    2016-01-01

    Context: Accumulated moderate physical activity (PA) for 30 min in a day is the only recommended treatment of prehypertension. Objective: We investigated autonomic modulation as a possible mechanism for the decrease in blood pressure (BP) during the rest periods in each 10 min session of PA. Design, Setting, and Participants: We conducted a single-blind randomized multi-arm control trial on 40 prehypertensive (pre-HT) young male adults. Methods: Participants were randomly divided by using random number table into four groups. Control (no intervention); Group 1 (walking at 50% of predicted VO2 peak); Group 2 (walking at 60% of predicted VO2 peak); Group 3 (walking at 70% of predicted VO2 peak). BP, heart rate variability (HRV), and heart rate recovery 1 min (HRR 1 min) were measured at baseline and during the rest period after each session of 10 min over 30 min of accumulated physical activity (PAcumm). Results: Significant diastolic BP (DBP) reduction (P < 0.001) was observed during the rest period after each session of PAcumm in intervention groups. An average reduction in DBP was more in pre-HT undertaking PAcumm at 70% of predicted VO2 Peak. Decrease in the mean value of low-frequency (LF) and LF/high-frequency ratio was observed following PAcumm in all intervention groups irrespective of the intensity of PA. No significant association of reduction of BP with HRV and HRR 1 s was observed. Conclusion: Reduction in BP was observed during the rest period after each 10 min session of PAcumm irrespective of the intensity of PA. Autonomic modulation does not seem to be the possible mechanism for the reduction in BP during the sessions. PMID:27843840

  6. Early, Prehospital Activation of the Walking Blood Bank Based on Mechanism of Injury Improves Time to Fresh Whole Blood Transfusion.

    PubMed

    Bassett, Aaron K; Auten, Jonathan D; Zieber, Tara J; Lunceford, Nicole L

    2016-01-01

    Balanced component therapy (BCT) remains the mainstay in trauma resuscitation of the critically battle injured. In austere medical environments, access to packed red blood cells, apheresis platelets, and fresh frozen plasma is often limited. Transfusion of warm, fresh whole blood (FWB) has been used to augment limited access to full BCT in these settings. The main limitation of FWB is that it is not readily available for transfusion on casualty arrival. This small case series evaluates the impact early, mechanism-of-injury (MOI)-based, preactivation of the walking blood bank has on time to transfusion. We report an average time of 18 minutes to FWB transfusion from patient arrival. Early activation of the walking blood bank based on prehospital MOI may further reduce the time to FWB transfusion.

  7. Functional activation of lymphocyte CD44 in peripheral blood is a marker of autoimmune disease activity.

    PubMed Central

    Estess, P; DeGrendele, H C; Pascual, V; Siegelman, M H

    1998-01-01

    Interactions between complementary receptors on leukocytes and endothelial cells play a central role in regulating extravasation from the blood and thereby affect both normal and pathologic inflammatory responses. CD44 on lymphocytes that has been "activated" to bind its principal ligand hyaluronate (HA) on endothelium can mediate the primary adhesion (rolling) of lymphocytes to vascular endothelial cells under conditions of physiologic shear stress, and this interaction is used for activated T cell extravasation into an inflamed site in vivo in mice (DeGrendele, H.C., P. Estess, L.J. Picker, and M.H. Siegelman. 1996. J. Exp. Med. 183:1119-1130. DeGrendele, H.D., P. Estess, and M.H. Siegelman. 1997. Science. 278:672-675. DeGrendele, H.C., P. Estess, and M.H. Siegelman. 1997. J. Immunol. 159: 2549-2553). Here, we have investigated the role of lymphocyte-borne-activated CD44 in the human and show that CD44-dependent primary adhesion is induced in human peripheral blood T cells through T cell receptor triggering. In addition, lymphocytes capable of CD44/HA-dependent rolling interactions can be found resident within inflamed tonsils. In analysis of peripheral bloods of patients from a pediatric rheumatology clinic, examining systemic lupus erythematosus, and a group of chronic arthropathies, expression of CD44-dependent primary adhesion strongly correlates with concurrent symptomatic disease, with 85% of samples from clinically active patients showing elevated levels of rolling activity (compared with only 4% of inactive patients). These rolling interactions are predominantly mediated by T cells. The results suggest that circulating T lymphocytes bearing activated CD44 are elevated under conditions of chronic inflammation and that these may represent a pathogenically important subpopulation of activated circulating cells that may provide a reliable marker for autoimmune or chronic inflammatory disease activity. PMID:9739051

  8. A comparative study on the influence of manganese on the bactericidal response of marine invertebrates.

    PubMed

    Oweson, Carolina; Hernroth, Bodil

    2009-09-01

    Manganese, Mn, is a naturally abundant metal in marine sediments. During hypoxic conditions the metal converts into a bioavailable state and can reach levels that have been shown immunotoxic to the crustacean Nephrops norvegicus. For this species it has previously been shown that exposure to 15 mg L(-1) of Mn decreased the number of circulating haemocytes while it for the echinoderm Asterias rubens increased the number of coelomocytes. Here, we compared if five days of exposure to the same concentration of Mn affects the bactericidal capacity of these two species and the mollusc Mytilus edulis when inoculated with the bacterium Vibrio parahaemolyticus. Viable counts of the bacteria were investigated at a time-course post-injection in the blood and the digestive glands of Mn-exposed and un-exposed (controls) animals. Accumulation of Mn was also analyzed in these tissues. When exposed to Mn the haemocyte numbers were significantly reduced in M. edulis and it was shown that the bactericidal capacity was impaired in the mussels as well as in N. norvegicus. This was most obvious in the digestive glands. These two species also showed the highest accumulation of the metal. In A. rubens the bactericidal capacity was not affected and the metal concentration was similar to the exposure concentration. After a recovery period of three days the concentration of Mn was significantly reduced in all three species. However, in M. edulis and N. norvegicus it was still double that of A. rubens which could explain the remaining bactericidal suppression observed in N. norvegicus. This study pointed out that exposure to such Mn-levels that are realistic to find in nature could have effects on the whole organism level, in terms of susceptibility to infections. The effect seemed associated to the accumulated concentration of Mn which differed on species level.

  9. [Data processing and blood transfusion activities: fact and future in 2013].

    PubMed

    Py, J-Y; Daurat, G

    2013-05-01

    It is now hard to think of blood transfusion activities without data processing. Blood transfusion centers are unable to work without it since a long time. Its necessity in hospital blood banks is following the same pattern. Electronic data interchange between them is growing because of their high interdependence. A lot has already been done and works routinely. But a lot remains to be done, due to continuous evolution of computer science and blood transfusion itself.

  10. Whole blood tissue factor procoagulant activity remains detectable during severe aplasia following bone marrow and peripheral blood stem cell transplantation.

    PubMed

    Ozcan, M; Morton, C T; Solovey, A; Dandelet, L; Bach, R R; Hebbel, R P; Slungaard, A; Key, N S

    2001-02-01

    Using a novel whole blood assay, we recently demonstrated that tissue factor procoagulant activity (TF PCA) is present in normal individuals. Preliminary experiments suggested that this activity is localized in the mononuclear cell fraction. Postulating that whole blood TF PCA would therefore be undetectable when monocytes and neutrophils are absent from peripheral blood, we assayed TF PCA during the peri-transplant period in 15 consecutive patients undergoing allogeneic (n = 12) or autologous (n = 3) bone marrow transplantation (BMT) or peripheral blood stem cell transplantation (PBSCT). Baseline (pre-transplant) mean TF PCA was higher in patients compared to normal controls (P <0.005). Unexpectedly, although TF PCA during the period of profound aplasia was significantly reduced compared to baseline (p <0.05), fully 55% of the initial activity remained detectable. During the engraftment phase, TF PCA returned to pre-transplant levels, with a linear correlation between monocyte counts and TF PCA (r = 0.63). In contrast to normal whole blood, incubation of aplastic samples with E. Coli lipopolysaccharide ex vivo failed to induce TF PCA. Throughout the period of study--but especially during the aplastic phase--the absolute number of circulating endothelial cells (CECs) that were TF antigen-positive was increased compared to normals (P <0.001). However, removal of these cells from whole blood samples failed to significantly diminish total TF PCA indicating that CECs alone could not account for the detectable TF PCA during aplasia. We conclude that neither circulating mature myelo-monocytic cells nor endothelial cells can account for all the functionally intact TF in peripheral blood. Further studies are needed to identify the other source(s) of TF PCA.

  11. Diurnal blood pressure variability and physical activity measured electronically and by diary.

    PubMed

    Gretler, D D; Carlson, G F; Montano, A V; Murphy, M B

    1993-02-01

    In order for 24 h ambulatory blood pressure monitoring (ABPM) to be useful in clinical decision making, it is necessary to quantify ambient physical activity and to develop appropriate norms of ambulatory pressure for different levels of activity. The present study has compared the predictive value of physical activity determined by an electronic activity monitor or a written diary, for concomitantly recorded blood pressure during ABPM in healthy normotensive subjects. Each subject wore four activity monitors, on the right and left wrists, on the left ankle and at the waist, respectively. Linear regression analysis was performed for each subject to determine the correlation between ABPM data (systolic and diastolic blood pressure and heart rate) and activity data (obtained from diaries and the four monitors). Significant differences in the degree of correlation were found for both the location of the activity monitor and the time (1/2, 2, 5, 10, 15, and 30 min preceding blood pressure measurement) over which activity was averaged (P < .05 by two-way analysis of variance). The best correlation was obtained with the activity monitor worn on the dominant wrist, and when activity was averaged over 2 to 10 min preceding blood pressure determination, accounting for 18 to 69% (mean 36 +/- 5%) of systolic blood pressure variation. Diaries performed similarly in these well-motivated subjects. It is concluded that because of the significant interaction between activity and blood pressure, ABPM data should be interpreted only in the light of concomitant activity data.(ABSTRACT TRUNCATED AT 250 WORDS)

  12. Bactericidal effect of colistin on planktonic Pseudomonas aeruginosa is independent of hydroxyl radical formation.

    PubMed

    Brochmann, Rikke Prejh; Toft, Anders; Ciofu, Oana; Briales, Alejandra; Kolpen, Mette; Hempel, Casper; Bjarnsholt, Thomas; Høiby, Niels; Jensen, Peter Østrup

    2014-02-01

    The bactericidal effect of several major types of antibiotics has recently been demonstrated to be dependent on the formation of toxic amounts of hydroxyl radicals (OH·) resulting from oxidative stress in metabolically active cells. Since killing by the antimicrobial peptide colistin does not require bacterial metabolic activity, we tested whether the bactericidal effect of colistin depends on the formation of OH·. In Pseudomonas aeruginosa cultures, OH-mediated killing by ciprofloxacin was demonstrated by decreased bacterial survival and induction of 3'-(p-hydroxyphenyl) fluorescein (HPF) fluorescence. OH·-mediated killing by ciprofloxacin was further confirmed by rescue of cells and reduction of HPF fluorescence due to prevention of OH· accumulation by scavenging with thiourea, by chelating with dipyridyl, by decreasing metabolism as well as by anoxic growth. In contrast, no formation of OH· was seen in P. aeruginosa during killing by colistin, and prevention of OH· accumulation could not rescue P. aeruginosa from killing by colistin. These results therefore demonstrate that the bactericidal activity of colistin on P. aeruginosa is not dependent on oxidative stress. In conclusion, antimicrobial peptides that do not rely on OH· formation should be considered for treatment of Gram-negative bacteria growing at low oxygen tension such as in endobronchial mucus and paranasal sinuses in cystic fibrosis patients, in abscesses and in infectious biofilm.

  13. Blood biochemical and cellular changes during decompression and simulated extravehicular activity

    NASA Technical Reports Server (NTRS)

    Jauchem, J. R.; Waligora, J. M.; Johnson, P. C. Jr

    1990-01-01

    Blood biochemical and cellular parameters were measured in human subjects before and after exposure to a decompression schedule involving 6 h of oxygen prebreathing. The exposure was designed to simulate extravehicular activity for 6 h (subjects performed exercise while exposed to 29.6 kPa). There were no significant differences between blood samples from subjects who were susceptible (n = 11) versus those who were resistant (n = 27) to formation of venous gas emboli. Although several statistically significant (P less than 0.05) changes in blood parameters were observed following the exposure (increases in white blood cell count, prothrombin time, and total bilirubin, and decreases in triglycerides, very-low-density lipoprotein cholesterol, and blood urea nitrogen), the changes were small in magnitude and blood factor levels remained within normal clinical ranges. Thus, the decompression schedule used in this study is not likely to result in blood changes that would pose a threat to astronauts during extravehicular activity.

  14. Effects of repeated blood samplings on locomotor activity, evasion and wheel-running activity in mice.

    PubMed

    Pfeil, R

    1988-01-01

    The effects of serial blood sampling on nocturnal locomotor activity, evasion, wheel-running activity and body mass were studied in male NMRI mice aged 7-8 weeks. The erythrocyte count, haematocrit and haemoglobin concentration at the beginning and end of the study showed no difference in group 1 (two samples per week, 0.08 ml each) while there was a significant decrease in the group 2 values (three samples per week, 0.08 ml each). The total amount of nocturnal locomotor activity decreased in the animals bled repeatedly while the periods with locomotor activity increased. These alterations appeared particularly after bleeding. In the test-group animals evasion showed a decrease compared with the untreated control animals, but there was no evidence of a relation to the timing of the bleedings.

  15. Bactericidal Antibiotics Induce Toxic Metabolic Perturbations that Lead to Cellular Damage.

    PubMed

    Belenky, Peter; Ye, Jonathan D; Porter, Caroline B M; Cohen, Nadia R; Lobritz, Michael A; Ferrante, Thomas; Jain, Saloni; Korry, Benjamin J; Schwarz, Eric G; Walker, Graham C; Collins, James J

    2015-11-03

    Understanding how antibiotics impact bacterial metabolism may provide insight into their mechanisms of action and could lead to enhanced therapeutic methodologies. Here, we profiled the metabolome of Escherichia coli after treatment with three different classes of bactericidal antibiotics (?-lactams, aminoglycosides, quinolones). These treatments induced a similar set of metabolic changes after 30 min that then diverged into more distinct profiles at later time points. The most striking changes corresponded to elevated concentrations of central carbon metabolites, active breakdown of the nucleotide pool, reduced lipid levels, and evidence of an elevated redox state. We examined potential end-target consequences of these metabolic perturbations and found that antibiotic-treated cells exhibited cytotoxic changes indicative of oxidative stress, including higher levels of protein carbonylation, malondialdehyde adducts, nucleotide oxidation, and double-strand DNA breaks. This work shows that bactericidal antibiotics induce a complex set of metabolic changes that are correlated with the buildup of toxic metabolic by-products.

  16. l-Glyceraldehyde 3-Phosphate, a Bactericidal Agent

    PubMed Central

    Tang, Chu-Tay; Engel, Robert; Tropp, Burton E.

    1977-01-01

    At a concentration of 2.5 mM, dl-glyceraldehyde 3-phosphate has a bactericidal effect upon Escherichia coli. The glycerol 3-phosphate transport system is required for the entry of the biologically active l-enantiomer. l-Glyceraldehyde must be phosphorylated by the cell to exert its full effect upon growth. The addition of dl-glyceraldehyde 3-phosphate to a culture of E. coli caused no preferential inhibition of the accumulation of deoxyribonucleic acid, ribonucleic acid, or phosphoglycerides, although protein accumulation was less affected. Studies with mutant strains ruled out catabolic glycerol 3-phosphate dehydrogenase, anabolic nicotinamide adenine dinucleotide (phosphate):sn-glycerol 3-phosphate oxidoreductase, and fructose 1,6-diphosphate aldolase as the primary sites of action. l-Glyceraldehyde 3-phosphate is a competitive inhibitor of sn-glycerol 3-phosphate in the reactions catalyzed by acyl coenzyme A:sn-glycerol 3-phosphate acyltransferase (Ki of 1.8 mM) and cytidine 5′-diphosphate-diglyceride:sn-glycerol 3-phosphate phosphatidyltransferase (Ki of 2.7 mM). A Km mutant for the former enzyme was susceptible to the inhibitor. l-Glyceraldehyde 3-phosphate does not affect acyl coenzyme A:lysophosphatidate acyltransferase activity. In vivo, phosphatidylethanolamine and phosphatidylglycerol accumulation are inhibited to the same extent by the addition of dl-glyceraldehyde 3-phosphate to a culture of E. coli. PMID:319747

  17. Bactericidal Effect of Silver Nanoparticles on Intramacrophage Brucella abortus 544

    PubMed Central

    Alizadeh, Hamed; Salouti, Mojtaba; Shapouri, Reza

    2014-01-01

    Background: Brucellosis is an infectious disease that is caused by Brucella spp. As Brucella spp. are intramacrophage pathogens, the treatment of this infection is very difficult. On the other hand, due to the side effects of the brucellosis treatment regime, it is necessary to find new antimicrobial agents against it. Objectives: The aim of this study was to investigate the antimicrobial effect of silver nanoparticles against Brucella abortus 544 in the intramacrophage condition. Materials and Methods: The antimicrobial effect of silver nanoparticles was determined by an agar well diffusion method. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of silver nanoparticles against B. abortus 544 were determined by a broth macrodilution method. The effect of time on the antimicrobial activity of silver nanoparticles was analyzed. The effect of silver nanoparticles on the intramacrophage survival of B. abortus 544 was studied on mice peritoneal macrophages. Results: The well diffusion agar study showed that silver nanoparticles have an antimicrobial effect on B. abortus 544. The MIC and MBC of silver nanoparticles against B. abortus 544 were; 6 ppm and 8 ppm, respectively. The silver nanoparticles showed antibacterial effects within 40 minutes. The results of the macrophage culture indicated that silver nanoparticles have antibacterial activity against intramacrophage B. abortus 544, and the highest efficiency was observed at a concentration of 8-10 ppm of silver nanoparticles. Conclusions: The results showed that silver nanoparticles have an antimicrobial effect against intramacrophage B. abortus 544. PMID:25147682

  18. Bioprotective properties of Dragon's blood resin: In vitro evaluation of antioxidant activity and antimicrobial activity

    PubMed Central

    2011-01-01

    Background Food preservation is basically done to preserve the natural characteristics and appearance of the food and to increase the shelf life of food. Food preservatives in use are natural, chemical and artificial. Keeping in mind the adverse effects of synthetic food preservatives, there is a need to identify natural food preservatives. The aims of this study were to evaluate in vitro antioxidant and antimicrobial activities of Dragon's blood resin obtained from Dracaena cinnabari Balf f., with a view to develop safer food preservatives. Methods In this study, three solvents of varying polarity were used to extract and separate the medium and high polarity compounds from the non-polar compounds of the Dragon's blood resin. The extracts were evaluated for their antimicrobial activity against the food borne pathogens. The antioxidant activities of the extracts were assessed using DPPH and ABTS radical scavenging, FRAP, metal chelating and reducing power assays. Total phenolics, flavonoids and flavonols of extracts were also estimated using the standard methods. Results Phytochemical analysis of extracts revealed high phenolic content in CH2Cl2 extract of resin. Free radical scavenging of CH2Cl2 extract was found to be highest which is in good correlation with its total phenolic content. All test microorganisms were also inhibited by CH2Cl2 extract. Conclusions Our result provide evidence that CH2Cl2 extract is a potential source of natural antioxidant compounds and exhibited good inhibitory activity against various food borne pathogens. Thus, CH2Cl2 extract of Dragon's blood resin could be considered as possible source of food preservative. PMID:21329518

  19. Smooth muscle BK channel activity influences blood pressure independent of vascular tone in mice

    PubMed Central

    Sachse, Gregor; Faulhaber, Jörg; Seniuk, Anika; Ehmke, Heimo; Pongs, Olaf

    2014-01-01

    The large conductance voltage- and Ca2+-activated K+ (BK) channel is an important determinant of vascular tone and contributes to blood pressure regulation. Both activities depend on the ancillary BKβ1 subunit. To determine the significance of smooth muscle BK channel activity for blood pressure regulation, we investigated the potential link between changes in arterial tone and altered blood pressure in BKβ1 knockout (BKβ1−/−) mice from three different genetically defined strains. While vascular tone was consistently increased in all BKβ1−/− mice independent of genetic background, BKβ1−/− strains exhibited increased (strain A), unaltered (strain B) or decreased (strain C) mean arterial blood pressures compared to their corresponding BKβ1+/+ controls. In agreement with previous data on aldosterone regulation by renal/adrenal BK channel function, BKβ1−/− strain A mice have increased plasma aldosterone and increased blood pressure. Consistently, blockade of mineralocorticoid receptors by spironolactone treatment reversibly restored the elevated blood pressure to the BKβ1+/+ strain A level. In contrast, loss of BKβ1 did not affect plasma aldosterone in strain C mice. Smooth muscle-restricted restoration of BKβ1 expression increased blood pressure in BKβ1−/− strain C mice, implying that impaired smooth muscle BK channel activity lowers blood pressure in these animals. We conclude that BK channel activity directly affects vascular tone but influences blood pressure independent of this effect via different pathways. PMID:24687584

  20. Secretory Leukocyte Protease Inhibitor Binds to Neisseria gonorrhoeae Outer Membrane Opacity Protein and is Bactericidal

    PubMed Central

    Cooper, Morris D.; Roberts, Melissa H.; Barauskas, Ona L.; Jarvis, Gary A.

    2012-01-01

    Problem Secretory leukocyte protease inhibitor (SLPI) is an innate immune peptide present on the genitourinary tract mucosa which has antimicrobial activity. In this study, we investigated the interaction of SLPI with Neisseria gonorrhoeae. Method of study ELISA and far-western blots were used to analyze binding of SLPI to gonococci. The binding site for SLPI was identified by tryptic digests and mass spectrometry. Antimicrobial activity of SLPI for gonococci was determined using bactericidal assays. SLPI protein levels in cell supernatants were measured by ELISA, and SLPI mRNA levels were assessed by quantitative RT-PCR. Results SLPI bound directly to the gonococcal Opa protein and was bactericidal. Epithelial cells from the reproductive tract constitutively expressed SLPI at different levels. Gonococcal infection of cells did not affect SLPI expression. Conclusion We conclude that SLPI is bactericidal for gonococci and is expressed by reproductive tract epithelial cells and thus is likely to play a role in the pathogenesis of gonococcal infection. PMID:22537232

  1. Blood Volume Response to Physical Activity and Inactivity

    DTIC Science & Technology

    2007-07-01

    physical activity through exposure to exercise ...ing physical activity . Reduced Physical Activity : Bed Rest If increased physical activity associated with reg- ular exercise results in hypervolemia... Activity : Exercise Increased physical activity provides the stimulus for action of several mechanisms that promote the expansion of plasma and

  2. Silver nanoparticles influence on the blood activation process and their release to blood plasma from synthetic polymer scaffold

    NASA Astrophysics Data System (ADS)

    Major, R.; Lackner, J. M.; Sanak, M.; Major, B.

    2016-03-01

    In the present work, blood and blood plasma interaction to silver stabilised polyelectrolytes was investigated in vitro. The designed materials are dedicated for regeneration of the cardiovascular system. Silver nanoparticles were introduced into the polyelectrolyte structure in order to reduce the risk of bacterial biofilm formation. The introduction of Ag nanoparticles occurred by deposition at high vacuum by magnetron sputtering. The analysis of blood-materials interactions were performed by using commercially available tester, Impact-R (Diamed). The assessment of silver ion nanoparticles release into the plasma consisted in determining the Prothrombin Time (PT) and Activated Partial Thromboplastin Time (APTT). Unmodified surface of polyelectrolytes is a strong activator for blood elements. The introduction of silver nanoparticles resulted in a significant reduction in the probability of clotting. The extrinsic pathway of coagulation determined on the basis of the PT and the intrinsic and common pathways of coagulation measured by the APTT did not indicate the danger out of range. Microstructure was studied using TEM on thin foils prepared from the cross-section of samples subjected to biomedical treatments. The observations revealed hetero- interface between two different crystalline solids.

  3. Alpha-Amylase Activity in Blood Increases after Pharmacological, But Not Psychological, Activation of the Adrenergic System

    PubMed Central

    Nater, Urs M.; La Marca, Roberto; Erni, Katja; Ehlert, Ulrike

    2015-01-01

    Background & Aim Alpha-amylase in both blood and saliva has been used as a diagnostic parameter. While studies examining alpha-amylase activity in saliva have shown that it is sensitive to physiological and psychological challenge of the adrenergic system, no challenge studies have attempted to elucidate the role of the adrenergic system in alpha-amylase activity in blood. We set out to examine the impact of psychological and pharmacological challenge on alpha-amylase in blood in two separate studies. Methods In study 1, healthy subjects were examined in a placebo-controlled, double-blind paradigm using yohimbine, an alpha2-adrenergic antagonist. In study 2, subjects were examined in a standardized rest-controlled psychosocial stress protocol. Alpha-amylase activity in blood was repeatedly measured in both studies. Results Results of study 1 showed that alpha-amylase in blood is subject to stronger increases after injection of yohimbine compared to placebo. In study 2, results showed that there was no significant effect of psychological stress compared to rest. Conclusions Alpha-amylase in blood increases after pharmacological activation of the adrenergic pathways suggesting that sympathetic receptors are responsible for these changes. Psychological stress, however, does not seem to have an impact on alpha-amylase in blood. Our findings provide insight into the mechanisms underlying activity changes in alpha-amylase in blood in healthy individuals. PMID:26110636

  4. Effect of Caffeine on near Maximal Blood Pressure and Blood Pressure Recovery in Physically-Active, College-Aged Females

    PubMed Central

    CONNAHAN, LAURA E.; OTT, CHRISTOPHER A.; BARRY, VAUGHN W.

    2017-01-01

    The purpose of this study is to determine how caffeine affects exercise blood pressure (BP) and active and passive recovery BP after vigorous intensity exercise in physically active college-aged females. Fifteen physically active, ACSM stratified low-risk females (age (y): 23.53 ± 4.07, weight (kg): 60.34 ± 3.67, height (cm): 165.14 ± 7.20, BMI (kg/m2): 22.18 ± 1.55) participated in two Bruce protocol exercise tests. Before each test participants consumed 1) a placebo or 2) 3.3 mg·kg−1 of caffeine at least one hour before exercise in a counterbalanced double-blinded fashion. After reaching 85% of their age-predicted maximum heart rate, BP was taken and participants began an active (i.e. walking) recovery phase for 6 minutes followed by a passive (i.e. sitting) recovery phase. BP was assessed every two minutes in each phase. Recovery times were assessed until active and passive BP equaled 20 mmHg and 10 mmHg above resting, respectively. Participants completed each test 1–2 weeks a part. Maximal systolic and diastolic blood pressures were not significantly different between the two trials. Active recovery, passive recovery, and total recovery times were all significantly longer during the caffeine trial than the placebo trial. Furthermore, the time to reach age-predicted maximum heart rate was significantly shorter in the placebo trial than the caffeine trial. While caffeine consumption did not significantly affect maximal blood pressure, it did affect active and passive recovery time following vigorous intensity exercise in physically active females. Exercise endurance also improved after consuming caffeine in this population. PMID:28344739

  5. Effect of Caffeine on near Maximal Blood Pressure and Blood Pressure Recovery in Physically-Active, College-Aged Females.

    PubMed

    Connahan, Laura E; Ott, Christopher A; Barry, Vaughn W

    2017-01-01

    The purpose of this study is to determine how caffeine affects exercise blood pressure (BP) and active and passive recovery BP after vigorous intensity exercise in physically active college-aged females. Fifteen physically active, ACSM stratified low-risk females (age (y): 23.53 ± 4.07, weight (kg): 60.34 ± 3.67, height (cm): 165.14 ± 7.20, BMI (kg/m(2)): 22.18 ± 1.55) participated in two Bruce protocol exercise tests. Before each test participants consumed 1) a placebo or 2) 3.3 mg·kg(-1) of caffeine at least one hour before exercise in a counterbalanced double-blinded fashion. After reaching 85% of their age-predicted maximum heart rate, BP was taken and participants began an active (i.e. walking) recovery phase for 6 minutes followed by a passive (i.e. sitting) recovery phase. BP was assessed every two minutes in each phase. Recovery times were assessed until active and passive BP equaled 20 mmHg and 10 mmHg above resting, respectively. Participants completed each test 1-2 weeks a part. Maximal systolic and diastolic blood pressures were not significantly different between the two trials. Active recovery, passive recovery, and total recovery times were all significantly longer during the caffeine trial than the placebo trial. Furthermore, the time to reach age-predicted maximum heart rate was significantly shorter in the placebo trial than the caffeine trial. While caffeine consumption did not significantly affect maximal blood pressure, it did affect active and passive recovery time following vigorous intensity exercise in physically active females. Exercise endurance also improved after consuming caffeine in this population.

  6. Endothelial Dysfunction and Blood Viscosity Inpatients with Unstable Angina in Different Periods of a Solar Activity

    NASA Astrophysics Data System (ADS)

    Parshina, S. S.; Tokaeva, L. K.; Dolgova, E. M.; Afanas'yeva, T. N.; Strelnikova, O. A.

    The origin of hemorheologic and endothelial defects in patients with unstable angina (comparing with healthy persons) is determined by a solar activity period: the blood viscosity increases in a period of high solar activity in the vessels of small, medium and macro diameters, a local decompensate dysfunction of small vessels endothelium had been fixed (microcirculation area). In the period of a low solar activity there is an increase of a blood viscosity in vessels of all diameters, generalized subcompensated endothelial dysfunction is developed (on the background of the III phase blood clotting activating). In the period of a high solar activity a higher blood viscosity had been fixed, comparing with the period of a low solar activity.

  7. In vitro assessment of blood compatibility: residual and dynamic markers of cellular activation.

    PubMed

    Johnson, Greg; Curry, Benjamin; Cahalan, Linda; Prater, Roni; Beeler, Michael; Gartner, Mark; Biggerstaff, John; Cahalan, Patrick

    2013-05-01

    The blood compatibility of materials and surfaces used for medical device fabrication is a crucial factor in their function and effectiveness. Expansion of device use into more sensitive and longer term applications warrants increasingly detailed evaluations of blood compatibility that reach beyond the customary measures mandated by regulatory requirements. A panel of tests that assess both deposition on the surface and activation of circulating blood in contact with the surface has been developed. Specifically, the ability of a surface to modulate the biological response of blood is assessed by measuring: (1) dynamic thrombin generation; (2) surface-bound thrombin activity after exposure to blood; (3) activation of monocytes, polymorphonuclear leukocytes, lymphocytes, and platelets; (4) activation of complement; and (5) adherent monocytes, polymorphonuclear leukocytes, lymphocytes, and platelets on blood-contacting surfaces. The tests were used to evaluate surfaces modified with immobilized heparin (Ension's proprietary bioactive surface) and demonstrated that the modified surfaces reduced platelet activation, leukocyte activation, and complement activation in flowing human blood. Perfusion of the surfaces with human platelet-rich plasma showed that the immobilized heparin surfaces also reduce both dynamic thrombin levels in the circulating plasma and residual thrombin generated at the material surface.

  8. The sorting of blood group active proteins during enucleation.

    PubMed

    Satchwell, Timothy J; Bell, Amanda J; Toye, Ashley M

    2015-04-01

    Enucleation represents the critical stage during red blood cell development when the nucleus is extruded from an orthochromatic erythroblast in order to generate a nascent immature reticulocyte. Extrusion of the nucleus results in loss of a proportion of the erythroblast plasma membrane, which surrounds the nucleus, the bulk of the endoplasmic reticulum and a small region of cytoplasm. For this reason enucleation provides an important point in erythroblast differentiation at which proteins not required for the function of the erythrocyte can be lost, whilst those that are important for the structure-function properties of the mature erythrocyte must be efficiently retained in the reticulocyte plasma membrane. Disturbances in protein distribution during enucleation are envisaged to occur during human diseases such as Hereditary Spherocytosis. This article will discuss the current knowledge of erythroblast enucleation in the context of retention and loss of proteins that display antigenic blood group sites and that exist within multiprotein complexes within the erythrocyte membrane.

  9. Comparison of bactericidal effects of commonly used antiseptics against pathogens causing nosocomial infections. Part 2.

    PubMed

    Yasuda, T; Yoshimura, Y; Takada, H; Kawaguchi, S; Ito, M; Yamazaki, F; Iriyama, J; Ishigo, S; Asano, Y

    1997-01-01

    Opportunistic infections caused by gram-negative rods (GNR), conventionally regarded as organisms with low or no pathogenicity, and intractable infections caused by various resistant organisms pose a great problem now. In view of this, we determined the bactericidal effects of 5 commonly used disinfectants using as the test strains Xanthomonas maltophilia and Serratia marcescens, chosen among other GNR since they often cause nosocomial infections. Regarding the bactericidal activities against X. maltophilia and S. marcescens, both sensitive strains and resistant strains were killed within 20 s of exposure to povidone-iodine and sodium hypochlorite. With chlorhexidine, 1 strain each of both species was not killed within 10 min of exposure at a concentration of 0.2%. Both sensitive strains and resistant strains of X. maltophilia were killed within 20 s of exposure to benzalkonium at 0.02%, while a concentration of 0.1% was required for benzalkonium to kill S. marcescens within 20 s. With Tego-51, both sensitive strains and resistant strains of X. maltophilia were killed within 20 s at 0.02%, while 1 strain of S. marcescens was not killed within 20 s at a concentration of 0.1%. In the use of disinfectants, comparative bactericidal effects of various disinfectants against clinical isolates should be taken into consideration.

  10. Sweeter but deadlier: decoupling size, charge and capping effects in carbohydrate coated bactericidal silver nanoparticles.

    PubMed

    de Oliveira, Luciane França; Gonçalves, Julianna de Oliveira; Gonçalves, Kaliandra de Almeida; Kobarg, Jörg; Cardoso, Mateus Borba

    2013-11-01

    Silver nanoparticles are widely used due to their biomedical-antibacterial applications. At the same time, the stabilization of these nanoparticles is challenging and may be made using polymeric carbohydrates, based on the practice of avoiding toxic chemicals and undesirable residues. In this study, we synthesized silver nanoparticles (AgNPs) which were stabilized by carbohydrates (potato starch and chitosan) and characterized by UV-Vis spectroscopy, zeta potential and transmission electron microscopy techniques. Bactericidal efficiency of AgNPs capped with different carbohydrates was tested demonstrating that the synthesized materials were able to inhibit the growth of two clinical/medical relevant bacteria strains (Escherichia coil and Staphylococcus aureus). AgNPs stabilized by chitosan presented enhanced bactericidal activity if compared to the ones synthesized in presence of potato starch. This difference is mainly attributed to the known antibacterial properties of chitosan associated to overall positive charge of the nanoparticles capped by this polymer. Those nanoparticles obtained in presence of starch presented minor bactericidal effects since the starch-capping agent is not able to contribute to the avoidance of bacteria growth and confers a quasi-neutral charge to the nanoparticle.

  11. Fabrication of nonfouling, bactericidal, and bacteria corpse release multifunctional surface through surface-initiated RAFT polymerization

    PubMed Central

    Wang, Bailiang; Ye, Zi; Tang, Yihong; Han, Yuemei; Lin, Quankui; Liu, Huihua; Chen, Hao; Nan, Kaihui

    2017-01-01

    Infections after surgery or endophthalmitis are potentially blinding complications caused by bacterial adhesion and subsequent biofilm formation on the intraocular lens. Neither single-function anti-adhesion surface nor contacting killing surface can exhibit ideal antibacterial function. In this work, a novel (2-(dimethylamino)-ethyl methacrylate-co-2-methacryloyloxyethyl phosphorylcholine) (p (DMAEMA-co-MPC)) brush was synthesized by “grafting from” method through reversible–addition fragmentation chain transfer polymerization. 1-Bromoheptane was used to quaternize the p (DMAEMA-co-MPC) brush coating and to endow the surface with bactericidal function. The success of the surface functionalization was confirmed by atomic force microscopy, water contact angle, and spectroscopic ellipsometry. The quaternary ammonium salt units were employed as efficient disinfection that can eliminate bacteria through contact killing, whereas the 2-methacryloyloxyethyl phosphorylcholine units were introduced to suppress unwanted nonspecific adsorption. The functionalized poly(dimethyl siloxane) surfaces showed efficiency in reducing bovine serum albumin adsorption and in inhibiting bacteria adhesion and biofilm formation. The copolymer brushes also demonstrated excellent bactericidal function against gram-positive (Staphylococcus aureus) bacteria measured by bacteria live/dead staining and shake-flask culture methods. The surface biocompatibility was evaluated by morphology and activity measurement with human lens epithelial cells in vitro. The achievement of the p (DMAEMA+-co-MPC) copolymer brush coating with nonfouling, bactericidal, and bacteria corpse release properties can be used to modify intraocular lenses. PMID:28053527

  12. Fabrication of nonfouling, bactericidal, and bacteria corpse release multifunctional surface through surface-initiated RAFT polymerization.

    PubMed

    Wang, Bailiang; Ye, Zi; Tang, Yihong; Han, Yuemei; Lin, Quankui; Liu, Huihua; Chen, Hao; Nan, Kaihui

    Infections after surgery or endophthalmitis are potentially blinding complications caused by bacterial adhesion and subsequent biofilm formation on the intraocular lens. Neither single-function anti-adhesion surface nor contacting killing surface can exhibit ideal antibacterial function. In this work, a novel (2-(dimethylamino)-ethyl methacrylate-co-2-methacryloyloxyethyl phosphorylcholine) (p (DMAEMA-co-MPC)) brush was synthesized by "grafting from" method through reversible-addition fragmentation chain transfer polymerization. 1-Bromoheptane was used to quaternize the p (DMAEMA-co-MPC) brush coating and to endow the surface with bactericidal function. The success of the surface functionalization was confirmed by atomic force microscopy, water contact angle, and spectroscopic ellipsometry. The quaternary ammonium salt units were employed as efficient disinfection that can eliminate bacteria through contact killing, whereas the 2-methacryloyloxyethyl phosphorylcholine units were introduced to suppress unwanted nonspecific adsorption. The functionalized poly(dimethyl siloxane) surfaces showed efficiency in reducing bovine serum albumin adsorption and in inhibiting bacteria adhesion and biofilm formation. The copolymer brushes also demonstrated excellent bactericidal function against gram-positive (Staphylococcus aureus) bacteria measured by bacteria live/dead staining and shake-flask culture methods. The surface biocompatibility was evaluated by morphology and activity measurement with human lens epithelial cells in vitro. The achievement of the p (DMAEMA(+)-co-MPC) copolymer brush coating with nonfouling, bactericidal, and bacteria corpse release properties can be used to modify intraocular lenses.

  13. Characterization of antigens from nontypable Haemophilus influenzae recognized by human bactericidal antibodies. Role of Haemophilus outer membrane proteins.

    PubMed Central

    Gnehm, H E; Pelton, S I; Gulati, S; Rice, P A

    1985-01-01

    Major outer membrane antigens, proteins, and lipopolysaccharides (LPSs), from nontypable Haemophilus influenzae were characterized and examined as targets for complement-dependent human bactericidal antibodies. Outer membranes from two nontypable H. influenzae isolates that caused otitis media and pneumonia (middle ear and transtracheal aspirates) were prepared by shearing organisms in EDTA. These membranes were compared with membranes prepared independently by spheroplasting and lysozyme treatment of whole cells and found to have: similar sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) patterns of the proteins; identical densities (rho = 1.22 g/cm3); and minimal d-lactose dehydrogenase activity indicating purity from cytoplasmic membranes. Outer membranes were solubilized in an LPS-disaggregating buffer and proteins were separated from LPS by molecular sieve chromatography. The SDS-PAGE patterns of outer membrane proteins (OMPs) from the two strains differed in the major band although other prominent bands appeared similar in molecular weight. LPS prepared by hot phenol water extraction of each of the strains contained 45% (pneumonia isolate) and 60% (otitis isolate) lipid (wt/wt), 49% and 50% carbohydrate (wt/wt), respectively, and less than 1%, 3-deoxy-manno octulosonic acid. Immunoglobulin M (IgM) purified from normal human serum (NHS) plus complement was bactericidal for both strains. Purified immunoglobulin G (IgG) from NHS killed the middle ear isolate and immune convalescent IgM from the serum of the patient with pneumonia killed his isolate. NHS or convalescent serum were absorbed with OMPs and LPS (0.6-110 micrograms) from each of the strains and immune specific inhibition of bactericidal antibody activity by each antigen was determined. OMPs from the pulmonary isolate inhibited bactericidal antibody activity directed against the isolate in both NHS (1.5 microgram of antigen) and immune serum (0.75 microgram of antigen). OMPs (60

  14. Blood selenium concentrations and enzyme activities related to glutathione metabolism in wild emperor geese

    USGS Publications Warehouse

    Franson, J. Christian; Hoffman, David J.; Schmutz, Joel A.

    2002-01-01

    In 1998, we collected blood samples from 63 emperor geese (Chen canagica) on their breeding grounds on the Yukon-Kuskokwim Delta (YKD) in western Alaska, USA. We studied the relationship between selenium concentrations in whole blood and the activities of glutathione peroxidase and glutathione reductase in plasma. Experimental studies have shown that plasma activities of these enzymes are useful biomarkers of selenium-induced oxidative stress, but little information is available on their relationship to selenium in the blood of wild birds. Adult female emperor geese incubating their eggs in mid-June had a higher mean concentration of selenium in their blood and a greater activity of glutathione peroxidase in their plasma than adult geese or goslings that were sampled during the adult flight feathermolting period in late July and early August. Glutathione peroxidase activity was positively correlated with the concentration of selenium in the blood of emperor geese, and the rate of increase relative to selenium was greater in goslings than in adults. The activity of glutathione reductase was greatest in the plasma of goslings and was greater in molting adults than incubating females but was not significantly correlated with selenium in the blood of adults or goslings. Incubating female emperor geese had high selenium concentrations in their blood, accompanied by increased glutathione peroxidase activity consistent with early oxidative stress. These findings indicate that further study of the effects of selenium exposure, particularly on reproductive success, is warranted in this species.

  15. Remote ischemia preconditioning increases red blood cell deformability through red blood cell-nitric oxide synthase activation.

    PubMed

    Grau, Marijke; Kollikowski, Alexander; Bloch, Wilhelm

    2016-09-12

    Remote ischemia preconditioning (rIPC), short cycles of ischemia (I) and reperfusion (R) of a region remote from the heart, protects against myocardial I/R injury. This effect is triggered by endothelial derived nitric oxide (NO) production. Red blood cells (RBC) are also capable of NO production and it is hypothesized that the beneficial effect of rIPC in terms of cardioprotection is strengthened by increased RBC dependent NO production and improved RBC function after rIPC maneuver. For this purpose, twenty male participants were subjected to four cycles of no-flow ischemia with subsequent reactive hyperemia within the forearm. Blood sampling and measurement of blood pressures and heart rate were carried out pre intervention, after each cycle and 15 min post intervention at both the non-treated and treated arm. These are the first results that show improved RBC deformability in the treated arm after rIPC cycles 1- 4 caused by significantly increased RBC-NO synthase activation. This in turn was associated to increased NO production in both arms after rIPC cycles 3 + 4. Also, systolic and diastolic blood pressures were decreased after rIPC. The findings lead to the conclusion that the cardioprotective effects associated with rIPC include improvement of the RBC-NOS/NO signaling in RBC.

  16. Bactericidal efficacy of nitric oxide-releasing silica nanoparticles

    PubMed Central

    Hetrick, Evan M.; Shin, Jae Ho; Stasko, Nathan A.; Johnson, C. Bryce; Wespe, Daniel A.; Holmuhamedov, Ekhson; Schoenfisch, Mark H.

    2013-01-01

    The utility of nitric oxide (NO)-releasing silica nanoparticles as a novel antibacterial is demonstrated against Pseudomonas aeruginosa. Nitric oxide-releasing nanoparticles were prepared via co-condensation of tetraalkoxysilane with aminoalkoxysilane modified with diazeniumdiolate NO donors, allowing for the storage of large NO payloads. Comparison of the bactericidal efficacy of the NO-releasing nanoparticles to 1-[2-(carboxylato)pyrrolidin-1-yl]diazen-1-ium-1,2-diolate (PROLI/NO), a small molecule NO donor, demonstrated enhanced bactericidal efficacy of nanoparticle-derived NO and reduced cytotoxicity to healthy cells (mammalian fibroblasts). Confocal microscopy revealed that fluorescently-labeled NO-releasing nanoparticles associated with the bacteria, providing rationale for the enhanced bactericidal efficacy of the nanoparticles. Intracellular NO concentrations were measurable when the NO was delivered from nanoparticles as opposed to PROLI/NO. Collectively, these results demonstrate the advantage of delivering NO via nanoparticles for antimicrobial applications. PMID:19206623

  17. A common mechanism of cellular death induced by bactericidal antibiotics.

    PubMed

    Kohanski, Michael A; Dwyer, Daniel J; Hayete, Boris; Lawrence, Carolyn A; Collins, James J

    2007-09-07

    Antibiotic mode-of-action classification is based upon drug-target interaction and whether the resultant inhibition of cellular function is lethal to bacteria. Here we show that the three major classes of bactericidal antibiotics, regardless of drug-target interaction, stimulate the production of highly deleterious hydroxyl radicals in Gram-negative and Gram-positive bacteria, which ultimately contribute to cell death. We also show, in contrast, that bacteriostatic drugs do not produce hydroxyl radicals. We demonstrate that the mechanism of hydroxyl radical formation induced by bactericidal antibiotics is the end product of an oxidative damage cellular death pathway involving the tricarboxylic acid cycle, a transient depletion of NADH, destabilization of iron-sulfur clusters, and stimulation of the Fenton reaction. Our results suggest that all three major classes of bactericidal drugs can be potentiated by targeting bacterial systems that remediate hydroxyl radical damage, including proteins involved in triggering the DNA damage response, e.g., RecA.

  18. Development of an automated, high-throughput bactericidal assay that measures cellular respiration as a survival readout for Neisseria meningitidis.

    PubMed

    Mak, Puiying A; Santos, George F; Masterman, Kelly-Anne; Janes, Jeff; Wacknov, Bill; Vienken, Kay; Giuliani, Marzia; Herman, Ann E; Cooke, Michael; Mbow, M Lamine; Donnelly, John

    2011-08-01

    Complement-mediated bactericidal activity has long been regarded as the serological correlate of protective immunity against Neisseria meningitidis. This was affirmed in 2005 at a WHO-sponsored meningococcal serology standardization workshop. The assay currently employed by most laboratories involves determining surviving bacterial colony counts on agar as a readout which is labor-intensive, time-consuming, and not amendable to rapid data analysis for clinical trials. Consequently, there is an acute need to develop a sensitive, high-throughput bactericidal assay to enable a rapid and robust assessment of the effectiveness of vaccine candidates. To this end, we have developed an automated, kinetic assay based on the fluorescent respiration product of resazurin which reduces assay volume, shortens assay time, and facilitates automation of data analysis. We demonstrate proof of concept for applicability of this high-throughput system with multiple meningococcal strains and utilizing different lots of human complement. The assay is robust and highly reproducible. Titers obtained by the fluorescence readout method are strongly correlated with the data obtained using the conventional, agar plate-based assay. These results demonstrate that the detection of bacteria that have survived the bactericidal reaction by measuring metabolic activity using a fluorescent dye as an alternative readout is a promising approach for the development of a high-throughput bactericidal assay.

  19. BLOOD PRESSURE DIPPING: ETHNICITY, SLEEP QUALITY AND SYMPATHETIC NERVOUS SYSTEM ACTIVITY

    PubMed Central

    Sherwood, Andrew; Routledge, Faye S.; Wohlgemuth, William K.; Hinderliter, Alan L.; Kuhn, Cynthia M.; Blumenthal, James A.

    2013-01-01

    Background Blunted blood pressure dipping is an established predictor of adverse cardiovascular outcomes. Although blunted blood pressure dipping is more common in African Americans than whites, the factors contributing to this ethnic difference are not well understood. This study examined the relationships of blood pressure dipping to ethnicity, body mass index, sleep quality, and fall in sympathetic nervous system activity during the sleep-period. Methods On 3 occasions, 128 participants with untreated high clinic blood pressure (130–159/85–99 mmHg) underwent assessments of 24-hour ambulatory blood pressure, sleep quality (evaluated by sleep interview, self-report, actigraphy) and sleep-period fall in sympathetic activity (measured by waking/sleep urinary catecholamine excretion). Results Compared to whites (n=72), African Americans (n=56) exhibited higher sleep-period systolic (p=.01) and diastolic blood pressure (p<.001), blunted systolic blood pressure dipping (p=.01), greater body mass index (p=.049) and poorer sleep quality (p=.02). Systolic blood pressure dipping was correlated with body mass index (r=−0.32, p<.001), sleep quality (r=0.30, p<.001), and sleep-period fall in sympathetic activity (r=0.30, p<.001). Multiple regression analyses indicated that these 3 factors were independent determinants of sleep-period systolic blood pressure dipping; ethnic differences in dipping were attenuated when controlling for these factors. Conclusions Blunted blood pressure dipping was related to higher body mass index, poorer sleep quality, and a lesser decline in sleep-period sympathetic nervous system activity. Although African American ethnicity also was associated with blunted dipping compared to whites in unadjusted analyses, this ethnic difference was diminished when body mass index, sleep quality and sympathetic activity were taken into account. PMID:21633397

  20. Impact of Physical Activity Interventions on Blood Pressure in Brazilian Populations

    PubMed Central

    Bento, Vivian Freitas Rezende; Albino, Flávia Barbizan; de Moura, Karen Fernandes; Maftum, Gustavo Jorge; dos Santos, Mauro de Castro; Guarita-Souza, Luiz César; Faria Neto, José Rocha; Baena, Cristina Pellegrino

    2015-01-01

    Background High blood pressure is associated with cardiovascular disease, which is the leading cause of mortality in the Brazilian population. Lifestyle changes, including physical activity, are important for lowering blood pressure levels and decreasing the costs associated with outcomes. Objective Assess the impact of physical activity interventions on blood pressure in Brazilian individuals. Methods Meta-analysis and systematic review of studies published until May 2014, retrieved from several health sciences databases. Seven studies with 493 participants were included. The analysis included parallel studies of physical activity interventions in adult populations in Brazil with a description of blood pressure (mmHg) before and after the intervention in the control and intervention groups. Results Of 390 retrieved studies, eight matched the proposed inclusion criteria for the systematic review and seven randomized clinical trials were included in the meta-analysis. Physical activity interventions included aerobic and resistance exercises. There was a reduction of -10.09 (95% CI: -18.76 to -1.43 mmHg) in the systolic and -7.47 (95% CI: -11.30 to -3.63 mmHg) in the diastolic blood pressure. Conclusions Available evidence on the effects of physical activity on blood pressure in the Brazilian population shows a homogeneous and significant effect at both systolic and diastolic blood pressures. However, the strength of the included studies was low and the methodological quality was also low and/or regular. Larger studies with more rigorous methodology are necessary to build robust evidence. PMID:26016783

  1. Overweight, physical activity and high blood pressure in children: a review of the literature.

    PubMed

    Torrance, Brian; McGuire, K Ashlee; Lewanczuk, Richard; McGavock, Jonathan

    2007-01-01

    Obesity is a growing problem in developed countries and is likely a major cause of the increased prevalence of high blood pressure in children. The aim of this review is to provide clinicians and clinical scientists with an overview of the current state of the literature describing the negative influence of obesity on blood pressure and it's determinants in children. In short, we discuss the array of vascular abnormalities seen in overweight children and adolescents, including endothelial dysfunction, arterial stiffening and insulin resistance. We also discuss the potential role of an increased activation of the sympathetic nervous system in the development of high blood pressure and vascular dysfunction associated with obesity. As there is little consensus regarding the methods to prevent or treat high blood pressure in children, we also provide a summary of the evidence supporting relationship between physical activity and blood pressure in children and adolescents. After reviewing a number of physical activity intervention studies performed in children, it appears as though 40 minutes of moderate to vigorous aerobic-based physical activity 3-5 days/week is required to improve vascular function and reduce blood pressure in obese children. Future studies should focus on describing the influence of physical activity on blood pressure control in overweight children.

  2. Luminol-, isoluminol- and lucigenin-enhanced chemiluminescence of rat blood phagocytes stimulated with different activators.

    PubMed

    Pavelkova, Martina; Kubala, Lukas

    2004-01-01

    Luminol-, isoluminol- or lucigenin-enhanced chemiluminescence (CL) was used to measure the production of reactive oxygen species by rat blood leukocytes. Opsonized zymosan (OZ), phorbol-12-myristate-13-acetate (PMA), calcium ionophore A23187 (Ca-I) or N-formyl-Met-Leu-Phe (fMLP) were used as activators. The CL signal of isolated blood leukocytes decreased in rank order of luminol > isoluminol > lucigenin. The kinetic profiles of luminol- and isoluminol-enhanced CL were similar upon stimulation by each activator tested. The remarkably higher luminol and isoluminol CL responses were obtained after OZ stimulation when compared with other activators. However, when lucigenin was used, the PMA- and OZ-stimulated CL were comparable. The presence of plasma increased OZ-activated CL because of the enhanced phagocytosis of OZ. This was demonstrated by determining the phagocytosis of the fluorescent OZ using a flow cytometer. In contrast, the presence of plasma decreased PMA-activated CL, due to the antioxidant properties of plasma as determined by the CL method. As far as whole blood is concerned, only OZ activated luminol-enhanced CL was reliable. Blood volumes over 5 microL decreased CL activity due to the scavenging ability of erythrocytes. The results suggest that 0.5 microL whole blood is sufficient for routine luminol-enhanced CL analysis of whole blood oxidative burst in rats.

  3. Keeping the blood flowing-plasminogen activator genes and feeding behavior in vampire bats.

    PubMed

    Tellgren-Roth, Asa; Dittmar, Katharina; Massey, Steven E; Kemi, Cecilia; Tellgren-Roth, Christian; Savolainen, Peter; Lyons, Leslie A; Liberles, David A

    2009-01-01

    The blood feeding vampire bats emerged from New World leaf-nosed bats that fed on fruit and insects. Plasminogen activator, a serine protease that regulates blood coagulation, is known to be expressed in the saliva of Desmodus rotundus (common vampire bat) and is thought to be a key enzyme for the emergence of blood feeding in vampire bats. To better understand the evolution of this biological function, we studied the plasminogen activator (PA) genes from all vampire bat species in light of their feeding transition to bird and subsequently mammalian blood. We include the rare species Diphylla ecaudata and Diaemus youngi, where plasminogen activator had not previously been studied and demonstrate that PA gene duplication observed in Desmodus is not essential to the vampire phenotype, but relates to the emergence of predominant mammalian blood feeding in this species. Plasminogen activator has evolved through gene duplication, domain loss, and sequence evolution leading to change in fibrin-specificity and susceptibility to plasminogen activator inhibitor-1. Before undertaking this study, only the four plasminogen activator isoforms from Desmodus were known. The evolution of vampire bat plasminogen activators can now be linked phylogenetically to the transition in feeding behavior among vampire bat species from bird to mammalian blood.

  4. Keeping the blood flowing—plasminogen activator genes and feeding behavior in vampire bats

    NASA Astrophysics Data System (ADS)

    Tellgren-Roth, Åsa; Dittmar, Katharina; Massey, Steven E.; Kemi, Cecilia; Tellgren-Roth, Christian; Savolainen, Peter; Lyons, Leslie A.; Liberles, David A.

    2009-01-01

    The blood feeding vampire bats emerged from New World leaf-nosed bats that fed on fruit and insects. Plasminogen activator, a serine protease that regulates blood coagulation, is known to be expressed in the saliva of Desmodus rotundus (common vampire bat) and is thought to be a key enzyme for the emergence of blood feeding in vampire bats. To better understand the evolution of this biological function, we studied the plasminogen activator (PA) genes from all vampire bat species in light of their feeding transition to bird and subsequently mammalian blood. We include the rare species Diphylla ecaudata and Diaemus youngi, where plasminogen activator had not previously been studied and demonstrate that PA gene duplication observed in Desmodus is not essential to the vampire phenotype, but relates to the emergence of predominant mammalian blood feeding in this species. Plasminogen activator has evolved through gene duplication, domain loss, and sequence evolution leading to change in fibrin-specificity and susceptibility to plasminogen activator inhibitor-1. Before undertaking this study, only the four plasminogen activator isoforms from Desmodus were known. The evolution of vampire bat plasminogen activators can now be linked phylogenetically to the transition in feeding behavior among vampire bat species from bird to mammalian blood.

  5. Activity-adjusted 24-hour ambulatory blood pressure and cardiac remodeling in children with sleep disordered breathing.

    PubMed

    Amin, Raouf; Somers, Virend K; McConnell, Keith; Willging, Paul; Myer, Charles; Sherman, Marc; McPhail, Gary; Morgenthal, Ashley; Fenchel, Matthew; Bean, Judy; Kimball, Thomas; Daniels, Stephen

    2008-01-01

    Questions remain as to whether pediatric sleep disordered breathing increases the risk for elevated blood pressure and blood pressure-dependent cardiac remodeling. We tested the hypothesis that activity-adjusted morning blood pressure surge, blood pressure load, and diurnal and nocturnal blood pressure are significantly higher in children with sleep disordered breathing than in healthy controls and that these blood pressure parameters relate to left ventricular remodeling. 24-hour ambulatory blood pressure parameters were compared between groups. The associations between blood pressure and left ventricular relative wall thickness and mass were measured. 140 children met the inclusion criteria. In children with apnea hypopnea index <5 per hour, a significant difference from controls was the morning blood surge. Significant increases in blood pressure surge, blood pressure load, and in 24-hour ambulatory blood pressure were evident in those whom the apnea hypopnea index exceeded 5 per hour. Sleep disordered breathing and body mass index had similar effect on blood pressure parameters except for nocturnal diastolic blood pressure, where sleep disordered breathing had a significantly greater effect than body mass index. Diurnal and nocturnal systolic blood pressure, diastolic blood pressure, and mean arterial blood pressure predicted the changes in left ventricular relative wall thickness. Therefore, sleep disordered breathing in children who are otherwise healthy is independently associated with an increase in morning blood pressure surge, blood pressure load, and 24-hour ambulatory blood pressure. The association between left ventricular remodeling and 24-hour blood pressure highlights the role of sleep disordered breathing in increasing cardiovascular morbidity.

  6. Rapid evaluation in whole blood culture of regimens for XDR-TB containing PNU-100480 (sutezolid), TMC207, PA-824, SQ109, and pyrazinamide.

    PubMed

    Wallis, Robert S; Jakubiec, Wesley; Mitton-Fry, Mark; Ladutko, Lynn; Campbell, Sheldon; Paige, Darcy; Silvia, Annette; Miller, Paul F

    2012-01-01

    There presently is no rapid method to assess the bactericidal activity of new regimens for tuberculosis. This study examined PNU-100480, TMC207, PA-824, SQ109, and pyrazinamide, singly and in various combinations, against intracellular M. tuberculosis, using whole blood culture (WBA). The addition of 1,25-dihydroxy vitamin D facilitated detection of the activity of TMC207 in the 3-day cultures. Pyrazinamide failed to show significant activity against a PZA-resistant strain (M. bovis BCG), and was not further considered. Low, mid, and high therapeutic concentrations of each remaining drug were tested individually and in a paired checkerboard fashion. Observed bactericidal activity was compared to that predicted by the sum of the effects of individual drugs. Combinations of PNU-100480, TMC207, and SQ109 were fully additive, whereas those including PA-824 were less than additive or antagonistic. The cumulative activities of 2, 3, and 4 drug combinations were predicted based on the observed concentration-activity relationship, published pharmacokinetic data, and, for PNU-100480, published WBA data after oral dosing. The most active regimens, including PNU-100480, TMC207, and SQ109, were predicted to have cumulative activity comparable to standard TB therapy. Further testing of regimens including these compounds is warranted. Measurement of whole blood bactericidal activity can accelerate the development of novel TB regimens.

  7. Bactericidal Effect of Photolysis of H2O2 in Combination with Sonolysis of Water via Hydroxyl Radical Generation

    PubMed Central

    Sheng, Hong; Nakamura, Keisuke; Kanno, Taro; Sasaki, Keiichi; Niwano, Yoshimi

    2015-01-01

    The bactericidal effect of hydroxyl radical (·OH) generated by combination of photolysis of hydrogen peroxide (H2O2) and sonolysis of water was examined under the condition in which the yield of ·OH increased additively when H2O2 aqueous solution was concomitantly irradiated with laser and ultrasound. The suspension of Staphylococcus aureus mixed with the different concentrations of H2O2 was irradiated simultaneously with a laser light (wavelength: 405 nm, irradiance: 46 and 91 mW/cm2) and ultrasound (power: 30 w, frequency: 1.65 MHz) at 20 ± 1°C of the water bulk temperature for 2 min. The combination of laser and ultrasound irradiation significantly reduced the viable bacterial count in comparison with the laser irradiation of H2O2 alone. By contrast, the ultrasound irradiation alone exerted almost no bactericidal effect. These results suggested that the combination effect of photolysis of H2O2 and sonolysis of water on bactericidal activity was synergistic. A multi-way analysis of variance also revealed that the interaction of H2O2 concentration, laser power and ultrasound irradiation significantly affected the bactericidal activity. Since the result of oxidative DNA damage evaluation demonstrated that the combination of laser and ultrasound irradiation significantly induced oxidative damage of bacterial DNA in comparison with the laser irradiation of H2O2 alone, it was suggested that the combination effect of photolysis of H2O2 and sonolysis of water on bactericidal activity would be exerted via oxidative damage of cellular components such as DNA. PMID:26148024

  8. Serum bactericidal resistance of faecal Escherichia coli and bactericidal competence of serum from patients with ulcerative colitis.

    PubMed Central

    Burke, D A; Clayden, S A; Axon, A T

    1990-01-01

    A microtitre method was developed to screen Escherichia coli from 48 patients with ulcerative colitis and 25 controls for serum resistance. Bactericidal resistance was indicated by a change in colour of indicator due to acid production by viable organisms and quantitated by a change in absorbance. The method clearly differentiated between organisms confirmed as resistant or sensitive by conventional techniques. Twenty four (50%) disease and 14 (56%) control E coli specimens showed serum resistance. Bactericidal competence of sera from patients with ulcerative colitis was assessed by incubating sensitive E coli with sera from 10 patients with ulcerative colitis and pooled normal serum. All sera effectively reduced viable counts to less than 6% of original inoculum. This study shows that serum samples from patients with ulcerative colitis are bactericidally competent and that there is no increase in the number of serum resistant E coli in patients with ulcerative colitis. PMID:2187904

  9. Hyaluronan and dextran modified tubes resist cellular activation with blood contact.

    PubMed

    Eckmann, David M; Tsai, Irene Y; Tomczyk, Nancy; Weisel, John W; Composto, Russell J

    2013-08-01

    This study was undertaken to evaluate the effects of thin film hyaluronic acid and dextran surface coatings to blunt cellular activation in a laboratory model of extracorporeal blood circulation. The inner lumen surface of polyurethane (PU) and poly(vinyl) chloride (PVC) tubing was grafted with hyaluronic acid and dextran. Surfaces were characterized for the presence of the grafted layer using ellipsometry, atomic force microscopy (AFM), and X-ray photoelectron spectroscopy (XPS). Persistence of the surface layer was maintained for up to 5 days of continuous exposure to shear flow using a Chandler loop apparatus. The Chandler loop method was used to study human whole blood activation activity. Whole blood aggregometry and flow cytometry measures of CD18, CD62L, CD62P, Annexin V and myeloperoxidase performed on blood samples exposed to the tubing for up to three hours were complemented by scanning electron microscopy (SEM) analysis of adherent cells and state of activation. In these studies commercial hospital products and uncoated PVC and PU tubes were used as controls. We found that hyaluranized PU and PVC conferred the greatest resistance to blood activation and that dextranization of the PU and PU tubing also provided significant diminution of the bioresponses measured. Based on our findings, we suggest that surface coating with hyaluronic acid or dextran acts as a potent shield from blood cellular activation during forms of extracorporeal circulation.

  10. Inhibition of the activation of Hageman factor (factor XII) by peripheral blood cells.

    PubMed Central

    Ratnoff, O D; Emanuelson, M M; Ziats, N P

    1987-01-01

    Suspensions of peripheral blood mononuclear cells (PBMC), monocytes, T or B lymphocytes, platelets or granulocytes, and cell-depleted supernatant fluids of these suspensions inhibited activation of Hageman factor (HF, Factor XII) by ellagic acid, a property not shared by erythrocytes. PBMC also inhibited HF activation by glass or sulfatides. Contaminating platelets may have contributed to inhibition by PBMC. Elaboration of agents inhibiting HF activation required metabolically active cells. The inhibitor(s) in PBMC supernates were not identified with known agents, but had properties of a nonenzymatic protein. PBMC supernates did not contain fibrinogen, nor alter the thrombin, prothrombin, or partial thromboplastin times of normal plasma, amidolysis by activated plasma thromboplastin antecedent (Factor XIa) or activated Stuart factor (Factor Xa) or esterolysis by C1 (C1 esterase); they inhibited plasmin minimally. These experiments suggest that peripheral blood cells may impede intravascular coagulation. Whether this property helps maintain the fluidity of blood is unclear. PMID:3498741

  11. Systems Biology of Coagulation Initiation: Kinetics of Thrombin Generation in Resting and Activated Human Blood

    PubMed Central

    Chatterjee, Manash S.; Denney, William S.; Jing, Huiyan; Diamond, Scott L.

    2010-01-01

    Blood function defines bleeding and clotting risks and dictates approaches for clinical intervention. Independent of adding exogenous tissue factor (TF), human blood treated in vitro with corn trypsin inhibitor (CTI, to block Factor XIIa) will generate thrombin after an initiation time (Ti) of 1 to 2 hours (depending on donor), while activation of platelets with the GPVI-activator convulxin reduces Ti to ∼20 minutes. Since current kinetic models fail to generate thrombin in the absence of added TF, we implemented a Platelet-Plasma ODE model accounting for: the Hockin-Mann protease reaction network, thrombin-dependent display of platelet phosphatidylserine, VIIa function on activated platelets, XIIa and XIa generation and function, competitive thrombin substrates (fluorogenic detector and fibrinogen), and thrombin consumption during fibrin polymerization. The kinetic model consisting of 76 ordinary differential equations (76 species, 57 reactions, 105 kinetic parameters) predicted the clotting of resting and convulxin-activated human blood as well as predicted Ti of human blood under 50 different initial conditions that titrated increasing levels of TF, Xa, Va, XIa, IXa, and VIIa. Experiments with combined anti-XI and anti-XII antibodies prevented thrombin production, demonstrating that a leak of XIIa past saturating amounts of CTI (and not “blood-borne TF” alone) was responsible for in vitro initiation without added TF. Clotting was not blocked by antibodies used individually against TF, VII/VIIa, P-selectin, GPIb, protein disulfide isomerase, cathepsin G, nor blocked by the ribosome inhibitor puromycin, the Clk1 kinase inhibitor Tg003, or inhibited VIIa (VIIai). This is the first model to predict the observed behavior of CTI-treated human blood, either resting or stimulated with platelet activators. CTI-treated human blood will clot in vitro due to the combined activity of XIIa and XIa, a process enhanced by platelet activators and which proceeds in the

  12. Empirical Dynamic Model Identification for Blood-Glucose Dynamics in Response to Physical Activity

    PubMed Central

    Dasanayake, Isuru S.; Seborg, Dale E.; Pinsker, Jordan E.; Doyle, Francis J.

    2016-01-01

    In this paper, the dynamic response of blood glucose concentration in response to physical activity of people with Type 1 Diabetes Mellitus (T1DM) is captured by subspace identification methods. Activity (input) and subcutaneous blood glucose measurements (output) are employed to construct a personalized prediction model through semi-definite programming. The model is calibrated and subsequently validated with non-overlapping data sets from 15 T1DM subjects. This preliminary clinical evaluation reveals the underlying linear dynamics between blood glucose concentration and physical activity. These types of models can enhance our capabilities of achieving tighter blood glucose control and early detection of hypoglycemia for people with T1DM. PMID:26997750

  13. Fibrinolytic Activity of Blood and its Determinants in Healthy Medical Students

    PubMed Central

    Shoeb, M.; Bose, S.

    2015-01-01

    Background Decreased fibrinolytic activity results in longer fibrinolysis time of blood and an increased propensity for hypercoagulable states of blood. Subjects with less fibrinolytic activity are prone to coronary artery disease, stroke and thromboembolic phenomena. Aim The study aims to identify the impact of gender, dietary habits, body mass index, physical activity level and menstrual cycle on fibrinolytic activity in healthy subjects. Settings and Design Cross-sectional study on randomly selected 206 healthy medical students aged 17 to 23 years. Materials and Methods Anthropometric measurements, dietary habits, physical activity level and menstrual history were obtained. Fibrinolysis time of fasting venous blood sample was determined by Euglobulin Lysis Time (ELT) method. Results Highly significant gender difference was noted in mean fibrinolytic activity (p=0.002). Mean fibrinolytic activity also showed a significant relationship with BMI (p=0.001) and with different phases of menstrual cycle in females (p=0.004). However, such relationship was not observed with diet and physical activity (p>0.05) in boys and girls. Conclusion Gender difference, body mass index and menstrual cycle phases have influences on the fibrinolytic activity of blood. This might be due to cyclical changes in the sex hormones levels, endometrium-derived plasmin and plasminogen activators and excess production of plasminogen activator inhibitor type-1 (PAI-I) in visceral adipocytes. PMID:26266114

  14. Xenoestrogenic activity in blood of European and Inuit populations

    PubMed Central

    Bonefeld-Jorgensen, Eva C; Hjelmborg, Philip S; Reinert, Thayaline S; Andersen, Birgitte S; Lesovoy, Vladimir; Lindh, Christian H; Hagmar, Lars; Giwercman, Aleksander; Erlandsen, Mogens; Manicardi, Gian-Carlo; Spanò, Marcello; Toft, Gunnar; Bonde, Jens Peter

    2006-01-01

    Background Human exposure to persistent organic pollutants (POPs) is ubiquitous and found in all individuals. Studies have documented endocrine disrupting effects and impact on reproduction. The aim of the present study was to compare the level of xenoestrogenic activity in serum of groups with varying POP exposure, and to evaluate correlations to the POP biomarkers, 2,2',4,4',5,5'-hexachlorobiphenyl (CB-153) and 1,1-dichloro-2,2-bis (p-chlorophenyl)-ethylene (p,p'-DDE). Methods The study included 358 men: Greenlandic Inuit's, Swedish fishermen, and Warsaw (Poland) and Kharkiv (Ukraine) inhabitants. Xenoestrogenicity of serum extracts alone (XER) and XER competitive (XERcomp) effect on 17β-estradiol induced estrogen receptor (ER) transactivity were assessed in the hormone free, lipophilic serum fraction containing the POPs using the MVLN human breast cancer cell line. Results No agonistic XER activity was exhibited for Inuit serum samples, while 12 – 24% of the European samples had detectable agonistic XER activity. On the contrary, 71% of Inuit serum samples antagonized XERcomp compared to 7 – 30 % in the other regions. XER and XERcomp were not or weakly correlated to the two POP markers. XER activity of Inuit samples was negatively associated to levels of CB-153 and p,p'-DDE. For the Warsaw group a positive and negative correlation between XER and p,p'-DDE and estradiol equivalence level and CB-153 levels was found. Conclusion No strong consistent association between xenoestrogenic net activity and the two POP markers was found. The results showed that the selected POP markers alone can not predict the integrated xenoestrogenic serum activity. Correlations to the POP markers were found at the extreme edge; the Inuit's and Warsaw study groups eliciting high frequency of samples with ER antagonistic and agonistic activity, respectively. We suggest that the variation in xenoestrogenic serum activity reflects differences in POP exposure mixture, genetic factors

  15. In vitro inhibition of blood cholinesterase activities from horse, cow, and rat by tetrachlorvinphos.

    PubMed

    Karanth, Subramanya; Pope, Carey

    2003-01-01

    The organophosphorus insecticide tetrachlorvinphos (TCVP) is commonly used as a feed-through larvicide in many livestock species, including cattle and horses. Cholinesterase (ChE) activity in blood (generally plasma or whole blood) is often employed to assess organophosphorus insecticide intoxication in animals as well as humans. In many species, including horse and man, plasma contains predominantly butyrylcholinesterase whereas red blood cells in all species express exclusively acetylcholinesterase. To evalulate the comparative interaction of TCVP with blood ChEs in different species, we compared the in vitro sensitivity of ChE activity in plasma and erythrocytes from horse, cow, and rat. Horse plasma ChE was most sensitive (IC(50), 30 minutes, 30 degrees C = 97 nM), whereas horse erythrocyte ChE activity was least sensitive (IC(50) > 1 mM). In contrast, cow plasma ChE showed lower sensitivity (IC(50) = 784 microM) to inhibition by TCVP than erythrocyte ChE (IC(50) = 216 microM). Rat plasma and erythrocyte ChE activities had relatively similar sensitivity to TCVP (IC(50) = 54 microM and 78 microM, respectively). The results suggest that plasma and erythrocyte ChE from horse, cow, and rat show marked species- and blood fraction-dependent differences in sensitivity to TCVP. Knowledge of such differences in sensitivity of blood ChE activities to TCVP may be important in the clinical interpretation of intoxication with this pesticide across species.

  16. [Activators, receptors and signal transduction pathways of blood platelets].

    PubMed

    Shaturnyĭ, V I; Shakhidzhanov, S S; Sveshnikova, A N; Panteleev, M A

    2014-01-01

    Platelet participation in hemostatic plug formation requires transition into an activated state (or, rather, variety of states) upon action of agonists like ADP, thromboxane A , collagen, thrombin, and others. The mechanisms of action for different agonists, their receptors and signaling pathways associated with them, as well as the mechanisms of platelet response inhibition are the subject of the present review. Collagen exposed upon vessel wall damage induced initial platelet attachment and start of thrombus formation, which involves numerous processes such as aggregation, activation of integrins, granule secretion and increase of intracellular Ca2+. Thrombin, ADP, thromboxane A , and ATP activated platelets that were not initially in contact with the wall and induce additional secretion of activating substances. Vascular endothelium and secretory organs also affect platelet activation, producing both positive (adrenaline) an d negative (prostacyclin, nitric oxide) regulators, thereby determining the relation of activation and inhibition signals, which plays a significant role in the formation of platelet aggregate under normal and pathological conditions. The pathways of platelet signaling are still incompletely understood, and their exploration presents an important objective both for basic cell biology and for the development of new drugs, the methods of diagnostics and of treatment of hemostasis disorders.

  17. In vitro shear stress-induced platelet activation: sensitivity of human and bovine blood.

    PubMed

    Lu, Qijin; Hofferbert, Bryan V; Koo, Grace; Malinauskas, Richard A

    2013-10-01

    As platelet activation plays a critical role in physiological hemostasis and pathological thrombosis, it is important in the overall hemocompatibility evaluation of new medical devices and biomaterials to assess their effects on platelet function. However, there are currently no widely accepted in vitro test methods to perform this assessment. In an effort to develop effective platelet tests for potential use in medical device evaluation, this study compared the sensitivity of platelet responses to shear stress stimulation of human and bovine blood using multiple platelet activation markers. Fresh whole blood samples anticoagulated with heparin or anticoagulant citrate dextrose, solution A (ACDA) were exposed to shear stresses up to 40 Pa for 2 min using a cone-and-plate rheometer model. Platelet activation was characterized by platelet counts, platelet surface P-selectin expression, and serotonin release into blood plasma. The results indicated that exposure to shear stresses above 20 Pa caused significant changes in all three of the platelet markers for human blood and that the changes were usually greater with ACDA anticoagulation than with heparin. In contrast, for bovine blood, the markers did not change with shear stress stimulation except for plasma serotonin in heparin anticoagulated blood. The differences observed between human and bovine platelet responses suggest that the value of using bovine blood for in vitro platelet testing to evaluate devices may be limited.

  18. Characterizing biological variability in livestock blood cholinesterase activity for biomonitoring organophosphate nerve agent exposure

    SciTech Connect

    Halbrook, R.S.; Shugart, L.R.; Watson, A.P.; Munro, N.B.; Linnabary, R.D. )

    1992-09-01

    A biomonitoring protocol, using blood cholinesterase (ChE) activity in livestock as a monitor of potential organophosphate nerve agent exposure during the planned destruction of US unitary chemical warfare agent stockpiles, is described. The experimental design included analysis of blood ChE activity in individual healthy sheep, horses, and dairy and beef cattle during a 10- to 12-month period. Castrated and sexually intact males, pregnant and lactating females, and adult and immature animals were examined through at least one reproductive cycle. The same animals were used throughout the period of observation and were not exposed to ChE-inhibiting organophosphate or carbamate compounds. A framework for an effective biomonitoring protocol within a monitoring area includes establishing individual baseline blood ChE activity for a sentinel group of 6 animals on the bases of blood samples collected over a 6-month period, monthly collection of blood samples for ChE-activity determination during monitoring, and selection of adult animals as sentinels. Exposure to ChE-inhibiting compounds would be suspected when all blood ChE activity of all animals within the sentinel group are decreased greater than 20% from their own baseline value. Sentinel species selection is primarily a logistical and operational concern; however, sheep appear to be the species of choice because within-individual baseline ChE activity and among age and gender group ChE activity in sheep had the least variability, compared with data from other species. This protocol provides an effective and efficient means for detecting abnormal depressions in blood ChE activity in livestock and can serve as a valuable indicator of the extent of actual plume movement and/or deposition in the event of organophosphate nerve agent release.

  19. Association of physical activity and physical fitness with blood pressure profile in Gujarati Indian adolescents.

    PubMed

    Shaikh, Wasim A; Patel, Minal C; Singh, S K

    2011-01-01

    The current study was conducted to determine how physical activity level and physical fitness affects the blood pressure profile of Gujarati Indian adolescents so as to help in developing preventive strategies for the local population as ethnic differences exist in the aetiopathogenesis of hypertension. A cross-sectional study was conducted on 485 Gujarati Indian adolescent boys and girls of age group 16-19 years. Physical activity level was assessed using Johnson Space Center/NASA Physical Activity Rating Scale and VO2 max was used to assess the physical fitness. Body composition was assessed in terms of Body Mass Index, Fat Mass Index and Waist Circumference. Blood Pressure was measured by oscillometry. One-way ANOVA was used to study if any significant differences (P<0.05) existed in the blood pressure profile between the high, moderate and low physical activity groups. Pearson's correlation coefficient was determined to assess the relationship between VO2 max and blood pressure profile. In girls, physical activity level was not found to have a significant effect on the blood pressure profile. In boys, systolic blood pressure and mean arterial pressure were found to be significantly higher in Moderate Physical Activity Group as compared to Low Physical Activity Group. PVO2 max was found to have a significant negative correlationship with SBP, DBP and MAP in girls and a significant negative correlationship with SBP, PP and MAP in boys. It could thus be concluded that a better physical fitness rather than a higher physical activity level could keep the blood pressure in check in the Gujarati Indian adolescents.

  20. Efficiency of Chlorine Dioxide as a Bactericide1

    PubMed Central

    Benarde, Melvin A.; Israel, Bernard M.; Olivieri, Vincent P.; Granstrom, Marvin L.

    1965-01-01

    We found chlorine dioxide to be a more effective disinfectant than chlorine in sewage effluent at pH 8.5. Chlorine dioxide was also found to be a more stable bactericide in relation to pH in the range studied. Images Fig. 1 PMID:5325940

  1. 21 CFR 1240.10 - Effective bactericidal treatment.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... equipment for at least 2 minutes in a lukewarm chlorine bath containing at least 50 ppm of available chlorine if hypochlorites are used or a concentration of equal bactericidal strength if chloramines are... the temperatures or with chlorine solutions as specified above, (1) with live steam from a hose if...

  2. 21 CFR 1240.10 - Effective bactericidal treatment.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... equipment for at least 2 minutes in a lukewarm chlorine bath containing at least 50 ppm of available chlorine if hypochlorites are used or a concentration of equal bactericidal strength if chloramines are... the temperatures or with chlorine solutions as specified above, (1) with live steam from a hose if...

  3. 21 CFR 1240.10 - Effective bactericidal treatment.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... equipment for at least 2 minutes in a lukewarm chlorine bath containing at least 50 ppm of available chlorine if hypochlorites are used or a concentration of equal bactericidal strength if chloramines are... the temperatures or with chlorine solutions as specified above, (1) with live steam from a hose if...

  4. 21 CFR 1240.10 - Effective bactericidal treatment.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... equipment for at least 2 minutes in a lukewarm chlorine bath containing at least 50 ppm of available chlorine if hypochlorites are used or a concentration of equal bactericidal strength if chloramines are... the temperatures or with chlorine solutions as specified above, (1) with live steam from a hose if...

  5. 21 CFR 1240.10 - Effective bactericidal treatment.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... equipment for at least 2 minutes in a lukewarm chlorine bath containing at least 50 ppm of available chlorine if hypochlorites are used or a concentration of equal bactericidal strength if chloramines are... the temperatures or with chlorine solutions as specified above, (1) with live steam from a hose if...

  6. Serum bactericidal assays to evaluate typhoidal and nontyphoidal Salmonella vaccines.

    PubMed

    Boyd, Mary Adetinuke; Tennant, Sharon M; Saague, Venant A; Simon, Raphael; Muhsen, Khitam; Ramachandran, Girish; Cross, Alan S; Galen, James E; Pasetti, Marcela F; Levine, Myron M

    2014-05-01

    Invasive Salmonella infections for which improved or new vaccines are being developed include enteric fever caused by Salmonella enterica serovars Typhi, Paratyphi A, and Paratyphi B and sepsis and meningitis in young children in sub-Saharan Africa caused by nontyphoidal Salmonella (NTS) serovars, particularly S. enterica serovars Typhimurium and Enteritidis. Assays are needed to measure functional antibodies elicited by the new vaccines to assess their immunogenicities and potential protective capacities. We developed in vitro assays to quantify serum bactericidal antibody (SBA) activity induced by S. Typhi, S. Paratyphi A, S. Typhimurium, and S. Enteritidis vaccines in preclinical studies. Complement from various sources was tested in assays designed to measure antibody-dependent complement-mediated killing. Serum from rabbits 3 to 4 weeks of age provided the best complement source compared to serum from pigs, goats, horses, bovine calves, or rabbits 8 to 12 weeks of age. For S. Enteritidis, S. Typhimurium, and S. Typhi SBA assays to be effective, bacteria had to be harvested at log phase. In contrast, S. Paratyphi A was equally susceptible to killing whether it was grown to the stationary or log phase. The typhoidal serovars were more susceptible to complement-mediated killing than were the nontyphoidal serovars. Lastly, the SBA endpoint titers correlated with serum IgG anti-lipopolysaccharide (LPS) titers in mice immunized with mucosally administered S. Typhimurium, S. Enteritidis, and S. Paratyphi A but not S. Typhi live attenuated vaccines. The SBA assay described here is a useful tool for measuring functional antibodies elicited by Salmonella vaccine candidates.

  7. Serum Bactericidal Assays To Evaluate Typhoidal and Nontyphoidal Salmonella Vaccines

    PubMed Central

    Boyd, Mary Adetinuke; Saague, Venant A.; Simon, Raphael; Muhsen, Khitam; Ramachandran, Girish; Cross, Alan S.; Galen, James E.; Pasetti, Marcela F.; Levine, Myron M.

    2014-01-01

    Invasive Salmonella infections for which improved or new vaccines are being developed include enteric fever caused by Salmonella enterica serovars Typhi, Paratyphi A, and Paratyphi B and sepsis and meningitis in young children in sub-Saharan Africa caused by nontyphoidal Salmonella (NTS) serovars, particularly S. enterica serovars Typhimurium and Enteritidis. Assays are needed to measure functional antibodies elicited by the new vaccines to assess their immunogenicities and potential protective capacities. We developed in vitro assays to quantify serum bactericidal antibody (SBA) activity induced by S. Typhi, S. Paratyphi A, S. Typhimurium, and S. Enteritidis vaccines in preclinical studies. Complement from various sources was tested in assays designed to measure antibody-dependent complement-mediated killing. Serum from rabbits 3 to 4 weeks of age provided the best complement source compared to serum from pigs, goats, horses, bovine calves, or rabbits 8 to 12 weeks of age. For S. Enteritidis, S. Typhimurium, and S. Typhi SBA assays to be effective, bacteria had to be harvested at log phase. In contrast, S. Paratyphi A was equally susceptible to killing whether it was grown to the stationary or log phase. The typhoidal serovars were more susceptible to complement-mediated killing than were the nontyphoidal serovars. Lastly, the SBA endpoint titers correlated with serum IgG anti-lipopolysaccharide (LPS) titers in mice immunized with mucosally administered S. Typhimurium, S. Enteritidis, and S. Paratyphi A but not S. Typhi live attenuated vaccines. The SBA assay described here is a useful tool for measuring functional antibodies elicited by Salmonella vaccine candidates. PMID:24623629

  8. An investigation of antioxidant and anti-inflammatory activities from blood components of Crocodile (Crocodylus siamensis).

    PubMed

    Phosri, Santi; Mahakunakorn, Pramote; Lueangsakulthai, Jiraporn; Jangpromma, Nisachon; Swatsitang, Prasan; Daduang, Sakda; Dhiravisit, Apisak; Thammasirirak, Sompong

    2014-10-01

    Antioxidant and anti-inflammatory activities were found from Crocodylus siamensis (C. siamensis) blood. The 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) radical scavenging, nitric oxide scavenging, hydroxyl radical scavenging and linoleic peroxidation assays were used to investigate the antioxidant activities of the crocodile blood. Results show that crocodile blood components had antioxidant activity, especially hemoglobin (40.58 % nitric oxide radical inhibition), crude leukocyte extract (78 % linoleic peroxidation inhibition) and plasma (57.27 % hydroxyl radical inhibition). Additionally, the anti-inflammatory activity of the crocodile blood was studied using murine macrophage (RAW 264.7) as a model. The results show that hemoglobin, crude leukocyte extract and plasma were not toxic to RAW 264.7 cells. Also they showed anti-inflammatory activity by reduced nitric oxide (NO) and interleukin 6 (IL-6) productions from lipopolysaccharide (LPS)-stimulated cells. The NO inhibition percentages of hemoglobin, crude leukocyte extract and plasma were 31.9, 48.24 and 44.27 %, respectively. However, only crude leukocyte extract could inhibit IL-6 production. So, the results of this research directly indicate that hemoglobin, crude leukocyte extract and plasma of C. siamensis blood provide both antioxidant and anti-inflammatory activities, which could be used as a supplementary agent in pharmaceutical products.

  9. Complement-mediated killing of Vibrio species by the humoral fluids of amphioxus Branchiostoma belcheri: implications for a dual role of O-antigens in the resistance to bactericidal activity.

    PubMed

    Li, Zhimin; Zhang, Shicui; Wang, Changfa; Pang, Qiuxiang

    2008-02-01

    The functional properties of complement in invertebrate deuterostomes are rather ill-defined. Here we showed that the humoral fluids from amphioxus Branchiostoma belcheri were capable of causing lysis of some Vibrio species including Vibrio alginolyticus HW284, Vibrio parahaemolyticus HW458 and Vibrio harvey SF-1, the first such data in the invertebrate deuterostomes. The fluid bacteriolytic activity was abolished by pre-incubation with heat-inactivated rabbit anti-human C3 serum, heating at 45 degrees C for 30 min, and repeated thawing and freezing. Additionally, the bacteriolytic activity was Mg(2+)-dependent and Ca(2+)-independent, and selective activation of the alternative pathway by zymosan A induced a loss of bacteriolytic activity. This strongly suggests that activation of the alternative complement pathway is responsible for the fluid bacteriolytic activity. It was also shown that some Vibrio species like Vibrio cincinnatiensis HW287 appeared resistant to the complement-mediated lysis. The LPS profiling revealed that the fluid-resistant V. cincinnatiensis HW287 had an LPS profile with a ladder of both high-molecular-weight (HMW) and low-molecular-weight (LMW) O-antigen bands, whereas the fluid-sensitive V. alginolyticus HW284 had few HMW O-antigen bands, suggesting a positive correlation between O-antigen size and humoral fluid resistance. Moreover, complement consumption assays demonstrated that both V. alginolyticus HW284 and V. cincinnatiensis HW287 consumed complement, with the former consuming significantly higher complement than the latter. Overall, it is suggested that HMW O-antigens may protect the fluid-resistant Vibrio species by a dual act of avoiding initiating complement activation as well as sterically hindering complement from gaining access to and damaging the cell membrane.

  10. [Lysosomal enzyme activity in white blood cells in leukemias].

    PubMed

    Rybakova, L P; Kharchenko, M F

    1996-01-01

    Total enzyme activity of acidic hydrolases and total neutral proteinase were compared in the post-nuclear fraction of leukocytes from healthy subjects and leukemia patients. The levels of acidic phosphotase and neutral proteinase in lymphoid cells of healthy donors were 11 and 7 times lower than those in myeloid cells, respectively. Patients suffering chronic myeloid leukemia revealed enhanced levels of beta-glucuronidase and neutral proteinases whereas B-chronic lymphoid leukemia involved acidic hydrolase concentrations lower than normal. As chronic myeloid leukemia advanced, neutral proteinase activity dropped dramatically (2.5 times); an aggressive course of B-chronic lymphoid leukemia was accompanied by a 3-fold decrease in acidic hydrolase level. The results may be used as indirect evidence of differences in the role of lysosomal enzymes in the mechanism of protein processing involved in myeloid and lymphoid proliferative pathologies.

  11. Regional Blood-Brain Barrier Responses to Central Cholinergic Activity

    DTIC Science & Technology

    1989-07-30

    regions were of particular interest because they show the largest decreases in glucose metabolism following limbic seizures ( Ben - Ari et al., 1981). It is...following seizures ( Ben - Ari et. al., 1981). The piriform cortex-amygdala also appears to be a generator of epileptiform activity in a variety of seizure...produced by PTZ. Such studies are ongoing and the results will be given in subsequent reports. 11 REFERENCES Ben - Ari , Y., D. Richie, E. Tremblay and G

  12. Activity of histidine in peripheral blood erythrocytes of pregnant women during exacerbation of cytomegalovirus infection.

    PubMed

    Lutsenko, M T; Andrievskaya, I A

    2014-10-01

    We studied the effect of active cytomegalovirus infection on histidine content in peripheral blood erythrocytes of pregnant women at gestation weeks 20-22 and its involvement into hemoglobin oxygenation. Using the histochemical technique developed by us, we studied the distribution of products of specific reaction for histidine in peripheral blood erythrocytes of pregnant women. The percentage of histidine-positive erythrocytes and their area were evaluated. The relationship between the distribution of the products of the reaction for histidine in peripheral blood erythrocytes of pregnant women and the titer of anti-cytomegalovirus IgG was revealed. The histidine content in peripheral blood erythrocytes of pregnant women with active cytomegalovirus infection was reduced, which impaired heme binding to globin and decreased the formation of oxyhemoglobin.

  13. Bactericidal effects of plasma-modified surface chemistry of silicon nanograss

    NASA Astrophysics Data System (ADS)

    Ostrikov, Kola; Macgregor-Ramiasa, Melanie; Cavallaro, Alex; (Ken Ostrikov, Kostya; Vasilev, Krasimir

    2016-08-01

    The surface chemistry and topography of biomaterials regulate the adhesion and growth of microorganisms in ways that are still poorly understood. Silicon nanograss structures prepared via inductively coupled plasma etching were coated with plasma deposited nanometer-thin polymeric films to produce substrates with controlled topography and defined surface chemistry. The influence of surface properties on Staphylococcus aureus proliferation is demonstrated and explained in terms of nanograss substrate wetting behaviour. With the combination of the nanograss topography; hydrophilic plasma polymer coatings enhanced antimicrobial activity while hydrophobic coatings reduced it. This study advances the understanding of the effects of surface wettability on the bactericidal properties of reactive nano-engineered surfaces.

  14. Ovotransferrin plays a major role in the strong bactericidal effect of egg white against the Bacillus cereus group.

    PubMed

    Baron, Florence; Jan, Sophie; Gonnet, Fabienne; Pasco, Maryvonne; Jardin, Julien; Giudici, Bérangère; Gautier, Michel; Guérin-Dubiard, Catherine; Nau, Françoise

    2014-06-01

    Bacillus cereus group bacteria are opportunistically pathogenic spore-forming microorganisms well known in the sector of pasteurized food products because of their involvement in spoilage events. In the sector of egg product processing, these bacteria may lead to important economic losses. It seemed then relevant to study their behavior in egg white, a widely used egg product usually recognized as developing different levels of antimicrobial activities depending on the environmental conditions. A strong bactericidal effect (decrease in the bacterial population of 6.1 ± 0.2 log CFU/ml) was observed for 68 B. cereus group isolates, independently incubated at 30°C in egg white at pH 9.3 (natural egg white pH). To determine which components could explain such a strong bactericidal effect, an experimental strategy was carried out, based on egg white fractionation by ultrafiltration and by anion-exchange liquid chromatography. The role of the protein fraction was thus demonstrated, and subsequent nano-liquid chromatography-tandem mass spectrometry analyses allowed identification of ovotransferrin as a major protein involved. The strong bactericidal effect was confirmed in the presence of commercial ovotransferrin. Such a bactericidal effect (i.e., a decrease in the bacterial population through cell death) had never been described because ovotransferrin is known for its bacteriostatic effect (i.e., inhibition of growth) due to its ability to chelate iron. Surprisingly, the addition of iron did not reverse the bactericidal effect of ovotransferrin under alkaline conditions (pH 9.3), whereas it completely reversed this effect at pH 7.3. Ovotransferrin was shown to provoke a perturbation of the electrochemical potential of the cytoplasmic membrane. A membrane disturbance mechanism could, hence, be involved, leading to the lysis of B. cereus group bacteria incubated in egg white.

  15. Semi-automated identification of white blood cell using active contour technique

    NASA Astrophysics Data System (ADS)

    Marzuki, Nurhanis Izzati Binti Che; Mahmood, Nasrul Humaimi Bin; Razak, Mohd Azhar Bin Abdul

    2015-05-01

    Manual and automated diagnosis can be used to identify the morphology of blood cells. However, the manual diagnosis of the blood cells is time consuming and need hematologist and pathologist experts in order to diagnose diseases. Recently, the automated diagnosis which is require image processing technique are often been used in this area. This paper focuses on image processing technique to do segmentation on the nucleus of white blood cells (WBC). To identify the nucleus region, there are several image processing techniques applied besides the active contour method. The results obtained show that the detection on the edge of the nucleus is almost same as the original image of the nucleus.

  16. Walking Activity, Body Composition and Blood Pressure in Adults with Intellectual Disabilities

    ERIC Educational Resources Information Center

    Stanish, Heidi I.; Draheim, Christopher C.

    2007-01-01

    Background: Individuals with intellectual disabilities engage in limited physical activity which places their health at risk. This study examined the walking activity, body composition and blood pressure of adults with intellectual disabilities. Methods: A group of male and female adults (n = 103) wore a pedometer for 7 days and were categorized…

  17. Evaluation of endotoxin (LPS) activity in bovine blood using neutrophil dependent chemiluminescence

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The purpose of this study was to evaluate the applicability of a neutrophil chemiluminescence-based assay for the measurement of LPS stimulatory activity in bovine whole blood. The assay is based on the capacity for LPS to trigger the respiratory oxidative burst activity (RBA) of autologous neutroph...

  18. Protein kinase C activity and the relations between blood lead and neurobehavioral function in lead workers.

    PubMed Central

    Hwang, Kyu-Yoon; Lee, Byung-Kook; Bressler, Joseph P; Bolla, Karen I; Stewart, Walter F; Schwartz, Brian S

    2002-01-01

    At picomolar concentrations, lead activates protein kinase C (PKC). This activation has been implicated in the neurotoxicity of lead. No prior study has evaluated the association of PKC activity with neurobehavioral function in humans. The purpose of this study was to determine whether PKC activity is associated with neurobehavioral function or modifies the relationship between blood lead levels and neurobehavioral test scores. In this cross-sectional study of 212 current lead workers in the Republic of Korea, we assessed blood lead levels, neurobehavioral test scores, and PKC activity. PKC activity was determined by measuring the levels of phosphorylation of three erythrocyte membrane proteins (spectrin and the 52-kDa and 48-kDa subunits of band 4.9), using an in vitro back-phosphorylation assay. When linear regression was used to control for confounding variables, blood lead was a significant predictor of decrements in performance on tests of psychomotor function, manual dexterity, and executive ability. In linear regression models, back-phosphorylation levels were not associated with neurobehavioral test scores, but when dichotomized at the median, back-phosphorylation levels modified the relationship between blood lead and test scores. For spectrin and the 52-kDa and 48-kDa subunits of band 4.9, 5, 2, and 5 of 14 interaction terms, respectively, had associated p-values less than 0.10, all with positive signs, indicating that blood lead was associated with worse test scores only in subjects with lower back-phosphorylation levels. These data indicate that blood lead levels are associated with decrements in neurobehavioral test scores, mainly in the domains of manual dexterity and psychomotor function, but only in subjects with lower in vitro back-phosphorylation levels, which is equivalent to higher in vivo PKC activity. We hypothesize that subjects with higher PKC activity in the presence of lead may be more susceptible to the health effects of lead. PMID

  19. Protein kinase C activity and the relations between blood lead and neurobehavioral function in lead workers.

    PubMed

    Hwang, Kyu-Yoon; Lee, Byung-Kook; Bressler, Joseph P; Bolla, Karen I; Stewart, Walter F; Schwartz, Brian S

    2002-02-01

    At picomolar concentrations, lead activates protein kinase C (PKC). This activation has been implicated in the neurotoxicity of lead. No prior study has evaluated the association of PKC activity with neurobehavioral function in humans. The purpose of this study was to determine whether PKC activity is associated with neurobehavioral function or modifies the relationship between blood lead levels and neurobehavioral test scores. In this cross-sectional study of 212 current lead workers in the Republic of Korea, we assessed blood lead levels, neurobehavioral test scores, and PKC activity. PKC activity was determined by measuring the levels of phosphorylation of three erythrocyte membrane proteins (spectrin and the 52-kDa and 48-kDa subunits of band 4.9), using an in vitro back-phosphorylation assay. When linear regression was used to control for confounding variables, blood lead was a significant predictor of decrements in performance on tests of psychomotor function, manual dexterity, and executive ability. In linear regression models, back-phosphorylation levels were not associated with neurobehavioral test scores, but when dichotomized at the median, back-phosphorylation levels modified the relationship between blood lead and test scores. For spectrin and the 52-kDa and 48-kDa subunits of band 4.9, 5, 2, and 5 of 14 interaction terms, respectively, had associated p-values less than 0.10, all with positive signs, indicating that blood lead was associated with worse test scores only in subjects with lower back-phosphorylation levels. These data indicate that blood lead levels are associated with decrements in neurobehavioral test scores, mainly in the domains of manual dexterity and psychomotor function, but only in subjects with lower in vitro back-phosphorylation levels, which is equivalent to higher in vivo PKC activity. We hypothesize that subjects with higher PKC activity in the presence of lead may be more susceptible to the health effects of lead.

  20. Whole blood assay for trypsin activity using polyanionic focusing gel electrophoresis.

    PubMed

    Lefkowitz, Roy B; Schmid-Schönbein, Geert W; Heller, Michael J

    2010-07-01

    The measurement of trypsin activity directly in blood is important for the development of novel diagnostics and for biomedical research. Presently, most degradative enzyme assays require sample preparation, making them time consuming, costly, and less accurate. We recently demonstrated a simple and rapid electrophoretic assay for the measurement of trypsin activity directly in whole blood. This assay utilizes a charge-changing fluorescent peptide substrate that produces a positively charged fluorescent product fragment upon cleavage by the target enzyme. This fragment is then rapidly separated from whole blood by electrophoresis and quantified with a fluorescent detector. In this study, we demonstrate that polyanionic poly-L-glutamic acid-doped polyacrylamide gels can focus the fluorescent cleavage product and markedly improve the LODs of the assay. A LOD of 2 pg in 6 microL (0.3 ng/mL) in whole human blood was achieved after a 1-h reaction of enzyme and substrate followed by 10 min of electrophoresis. This is 50- to 200-fold better than the estimated reference levels for trypsin (15-60 ng/mL) in blood. This straightforward technique now allows for the rapid measurement of clinically relevant levels of trypsin activity in microliter volumes of whole blood, providing a useful tool for the development of novel point-of-care diagnostics.

  1. Human muscle nerve sympathetic activity at rest. Relationship to blood pressure and age

    PubMed Central

    Sundlöf, G.; Wallin, B. G.

    1978-01-01

    1. Recordings of multi-unit sympathetic activity were made from median or peroneal muscle nerve fascicles in thirty-three healthy subjects, resting in recumbent position. Simultaneous recordings of intra-arterial blood pressure were made in seventeen subjects. The neural activity, quantified by counting the number of pulse synchronous sympathetic bursts in the mean voltage neurogram (burst incidence), was plotted against the arterial blood pressure level and the age of the subjects. The effects of spontaneous temporary blood pressure fluctuations were studied by correlating different pressure parameters of individual heart beats to the probability of occurrence of a sympathetic burst and to the amplitude of the occurring burst. 2. Between different subjects there were marked differences in burst incidence, from less than 10 to more than 90 bursts/100 heart beats. No correlation was found to interindividual differences in the arterial blood pressure level but there was a slight tendency for increasing burst incidence with increasing age. 3. Irrespective of the magnitude of the burst incidence, the bursts always occurred more frequently during spontaneous transient blood pressure reductions than during transient increases in blood pressure. When, for each heart cycle, the occurrence of a sympathetic burst was correlated with different blood pressure parameters there was regularly a close negative correlation to diastolic pressure, a low correlation to systolic and an intermediary negative correlation to mean blood pressure. There was a positive correlation to pulse pressure and to pulse interval. 4. When measured for individual heart beats, not only the occurrence but also the mean voltage amplitude of the sympathetic bursts tended to increase with decreasing diastolic pressure. 5. In a given subject when comparing heart beats with the same diastolic pressure, the occurrence as well as the amplitude of the sympathetic bursts was higher for heart beats occurring

  2. [Microbiological assesssment of efficiency chemothermal disinfection of blood contaminated hospital textiles].

    PubMed

    Röhm-Rodowald, Ewa; Jakimiak, Bozenna; Podgórska, Marta; Chojecka, Agnieszka

    2010-01-01

    Thermal disinfection should be applied to laundering procedures of hospital textiles contaminated with blood. Currently, there is an increasing number of hospital textiles composed of cotton-polyester blends that cannot endure high temperatures of thermal disinfection. Besides, decreasing the temperature of chemothermal disinfection enhances the possibility of micro-organisms to survive the laundering procedure. The aim of this study was to prepare a new method for the microbiological evaluation of disinfecting laundering procedures for hospital textiles contaminated with blood. The bactericidal activity of chemical disinfectants for chemothermal disinfection was determined by simulating a laundering procedure for hospital textiles in the laboratory according to procedure of National Institute of Hygiene - DF/05/03. Bioindicators cotton carriers inoculated with Enterococcus faecium were used for determinating the antibacterial effects for hospital textiles contaminated with blood. High concentrations of bovine albumin and/or sheep erythrocytes were used as substrate for simulating human blood. The results showed that the bactericidal activity of chemical disinfectants for chemothermal disinfection hospital textiles in the event of massive organic contamination--heavily soiled with blood, shall be evaluated using carrier test in following conditions: test organism- Enterococcus faecium, interfering substances--6 g/l bovine albumin solution added to preparation.

  3. Interaction Of ZnO Nanoparticles With Food Borne Pathogens Escherichia coli DH5α and Staphylococcus aureus 5021 & Their Bactericidal Efficacy

    NASA Astrophysics Data System (ADS)

    Kaur, Pawan; Thakur, Rajesh; Kumar, Sandeep; Dilbaghi, Neeraj

    2011-12-01

    Bactericidal activity of ZnO nanoparticles (np) against the food borne pathogens E. coli DH5α (Gram-ve) and & S. aureus 5021 (Gram+ve), and the mechanism of their interaction with target microbes was studied. Bactericidal activity of ZnO np was attributed to disruption of cell membrane causing cytoplasmic leakage, which was measured by quantifying the leakage of nucleic acids, proteins and K+ ions from the cells using UV-VIS Spectrophotometry and Atomic Absorption Spectrophotometry, respectively. Cell membrane disruption was observed through TEM. It is proposed that both the abrasiveness and the surface oxygen species of ZnO np are responsible for their biocidal properties.

  4. Antimicrobial activity of ProRoot MTA in contact with blood

    PubMed Central

    Farrugia, C.; Baca, P.; Camilleri, J.; Arias Moliz, M. T.

    2017-01-01

    Dental materials based on Portland cement, which is used in the construction industry have gained popularity for clinical use due to their hydraulic properties, the interaction with tooth tissue and their antimicrobial properties. The antimicrobial properties are optimal in vitro. However in clinical use contact with blood may affect the antimicrobial properties. This study aims to assess whether antimicrobial properties of the Portland cement-based dental cements such as mineral trioxide aggregate (MTA) are also affected by contact with blood present in clinical situations. ProRoot MTA, a Portland cement-based dental cement was characterized following contact with water, or heparinized blood after 1 day and 7 days aging. The antimicrobial activity under the mentioned conditions was assessed using 3 antimicrobial tests: agar diffusion test, direct contact test and intratubular infection test. MTA in contact with blood was severely discoloured, exhibited an additional phosphorus peak in elemental analysis, no calcium hydroxide peaks and no areas of bacterial inhibition growth in the agar diffusion test were demonstrated. ProRoot MTA showed limited antimicrobial activity, in both the direct contact test and intratubular infection test. When aged in water ProRoot MTA showed higher antimicrobial activity than when aged in blood. Antimicrobial activity reduced significantly after 7 days. Further assessment is required to investigate behaviour in clinical situations. PMID:28128328

  5. Rapid and reliable determination of the halogenating peroxidase activity in blood samples.

    PubMed

    Flemmig, Jörg; Schwarz, Pauline; Bäcker, Ingo; Leichsenring, Anna; Lange, Franziska; Arnhold, Jürgen

    2014-12-15

    By combining easy and fast leukocyte enrichment with aminophenyl-fluorescein (APF) staining we developed a method to quickly and specifically address the halogenating activity of the immunological relevant blood heme peroxidases myeloperoxidase and eosinophil peroxidase, respectively. For leukocyte enrichment a two-fold hypotonic lysis procedure of the blood with Millipore water was chosen which represents a cheap, fast and reliable method to diminish the amount of erythrocytes in the samples. This procedure is shown to be suitable both to human and murine blood micro-samples, making it also applicable to small animal experiments with recurring blood sampling. As all types of leukocytes are kept in the sample during the preparation, they can be analysed separately after discrimination during the flow cytometry analysis. This also holds for all heme peroxidase-containing cells, namely neutrophils, eosinophils and monocytes. Moreover additional parameters (e.g. antibody staining) can be combined with the heme peroxidase activity determination to gain additional information about the different immune cell types. Based on previous results we applied APF for specifically addressing the halogenating activity of leukocyte peroxidases in blood samples. This dye is selectively oxidized by the MPO and EPO halogenation products hypochlorous and hypobromous acid. This approach may provide a suitable tool to gain more insights into the immune-physiological role of the halogenating activity of heme peroxidases.

  6. Antimicrobial activity of ProRoot MTA in contact with blood.

    PubMed

    Farrugia, C; Baca, P; Camilleri, J; Arias Moliz, M T

    2017-01-27

    Dental materials based on Portland cement, which is used in the construction industry have gained popularity for clinical use due to their hydraulic properties, the interaction with tooth tissue and their antimicrobial properties. The antimicrobial properties are optimal in vitro. However in clinical use contact with blood may affect the antimicrobial properties. This study aims to assess whether antimicrobial properties of the Portland cement-based dental cements such as mineral trioxide aggregate (MTA) are also affected by contact with blood present in clinical situations. ProRoot MTA, a Portland cement-based dental cement was characterized following contact with water, or heparinized blood after 1 day and 7 days aging. The antimicrobial activity under the mentioned conditions was assessed using 3 antimicrobial tests: agar diffusion test, direct contact test and intratubular infection test. MTA in contact with blood was severely discoloured, exhibited an additional phosphorus peak in elemental analysis, no calcium hydroxide peaks and no areas of bacterial inhibition growth in the agar diffusion test were demonstrated. ProRoot MTA showed limited antimicrobial activity, in both the direct contact test and intratubular infection test. When aged in water ProRoot MTA showed higher antimicrobial activity than when aged in blood. Antimicrobial activity reduced significantly after 7 days. Further assessment is required to investigate behaviour in clinical situations.

  7. Antibody-mediated sialidase activity in blood serum of patients with multiple myeloma.

    PubMed

    Bilyy, Rostyslav; Tomin, Andriy; Mahorivska, Iryna; Shalay, Olga; Lohinskyy, Volodymyr; Stoika, Rostyslav; Kit, Yuriy

    2011-01-01

    Cell surface sialylation is known to be tightly connected with tumorigenicity, invasiveness, metastatic potential, clearance of aged cells, while the sialylation of IgG molecules determines their anti-inflammatory properties. Four sialidases - hydrolytic enzymes responsible for cleavage of sialic residues - were described in different cellular compartments. However, sialidases activity in body fluids, and specifically in blood serum, remains poorly studied. Here, we characterize first known IgG antibodies possessing sialidase-like activity in blood serum of multiple myeloma (MM) patients. Ig fractions were precipitated with ammonium sulfate (50% of saturation) from blood serum of 12 healthy donors and 14 MM patients, and screened for the presence of sialidase activity by using 4-MUNA (2'-(4-methylumbelliferyl)-α-D-N-acetylneuraminic acid) as substrate. High level of sialidase activity was detected in the MM patients, but not in healthy donors. Subsequent antibody purification by protein-G affinity chromatography and HPLC size exclusion chromatography at acidic conditions demonstrated that sialidase activity was attributable to IgG molecules. Sialidase activity was also specific for (Fab)(2) fragment of IgG and blocked by sialidase inhibitor DANA. Sialidase activity of IgG molecule was also confirmed by in gel assay for cleavage of sialidase substrate. Kinetic parameters of the catalysis reaction were described by Michaelis-Menten equation with K(m)  = 44.4-108 µM and k(cat) = 2.7-23.1 min(-1). The action of IgG possessing sialidase-like activity towards human red blood cells resulted in a subsequent increase in their agglutination by the peanut agglutinin, that confirms their desialylation by the studied IgG. This is the first demonstration of the intrinsic sialidase activity of IgG isolated from blood serum of MM patients.

  8. Synthesis and potential applications of silver-porous aluminium oxide nanocomposites as prospective antiseptics and bactericides.

    PubMed

    Gorbunova, Marina; Lemkina, Larisa; Lebedeva, Irina; Kisel'kov, Dmitriy; Chekanova, Larisa

    2017-03-01

    Alumina micro-spheres with mesoporous structure called porous aluminium oxide (POA) were prepared through a hydrothermal method using Al2(SO4)3·18H2O followed by a thermal decomposition process. Silver nanocomposites of POA (Ag/POAs) with high biochemical activity were synthesized by sorption of silver nanoparticles in the matrix of POA. Synthesis of Ag/POAs using photochemical reduction enables the producing silver nanoparticles preventing their aggregation. Ag/POAs demonstrated a stronger bactericidal activity than POA. The colony-forming ability of Escherichia coli was completely lost in 1 day on Ag/POAs at silver nanoparticles concentration of 0.241 ppm. Staphylococcus epidermidis displayed higher tolerance to Ag/POAs at all silver nanoparticles concentrations, the growth of Staphylococcus epidermidis was stopped at concentration of 0.374 ppm. The bactericidal activity of Ag/POAs against bacteria in drinking water was found to be highly effective, the growth of bacteria was completely lost in 1 day at silver nanoparticles concentration of 0.108 ppm.

  9. Bactericidal Effects of HVOF-Sprayed Nanostructured TiO2 on Pseudomonas aeruginosa

    NASA Astrophysics Data System (ADS)

    Jeffery, B.; Peppler, M.; Lima, R. S.; McDonald, A.

    2010-01-01

    Titanium dioxide (TiO2) has been shown to exhibit photocatalytic bactericidal activity. This preliminary study focused on examining the photocatalytic activity of high-velocity oxy-fuel (HVOF) sprayed nanostructured TiO2 coatings to kill Pseudomonas aeruginosa. The surfaces of the nanostructured TiO2 coatings were lightly polished before addition of the bacterial solution. Plates of P. aeruginosa were grown, and then suspended in a phosphate buffer saline (PBS) solution. The concentration of bacteria used was determined by a photo-spectrometer, which measured the amount of light absorbed by the bacteria-filled solution. This solution was diluted and pipetted onto the coating, which was exposed to white light in 30-min intervals, up to 120 min. It was found that on polished HVOF-sprayed coatings exposed to white light, 24% of the bacteria were killed after exposure for 120 min. On stainless steel controls, approximately 6% of the bacteria were not recovered. These preliminary results show that thermal-sprayed nanostructured TiO2 coatings exhibited photocatalytic bactericidal activity with P. aeruginosa.

  10. "Blood Stains" on Tethys: Evidence for Recent Activity?

    NASA Astrophysics Data System (ADS)

    Schenk, P.

    2015-12-01

    Distinctive set of arcuate, reddish-colored lineaments has been identified on Tethys. These markings are slightly darker than adjacent cratered terrains but have a flatter green-IR spectral slope. There are at least three prominent sets in the northern hemisphere centered on the anti-Saturn meridian. Each set consists of ~5-10 parallel lineations a few kilometers across and 50-250 km long. The lineations are remarkably curvilinear (i.e., non-sinuous) and not deflected by major impact structures: they cross uninterrupted the floor of 400-km-diameter, 10-km-deep Odysseus impact basin. In one area (~25° N, 185°W), high-resolution mapping at ~90-125 m/pixel shows no discrete scarp, ridge, or other tectonic manifestation along the feature. Instead, only a faint discoloration and ~25 small dark spots 200-800 m in diameter have been identified. These spots are characterized by very low albedos, sharp boundaries, and no evidence of raised rims expected with impact origin. Of these, ~60% (15) are at the bottom of small craters. The IR lineaments show remarkable symmetry centered on the tidal axis with Saturn. Exogenic mechansims are ruled out by geometry and geology, hence we explore possible endogenic origins. Stress mechanisms being tested include non-synchronous rotation (considered unlikely for a cold, triaxial body like Tethys), tidal recession and true polar wander. The lack of obvious tectonic deformation despite the strong color signature is unusual (although structures may exist below the current resolution limit). Though unlikely, the lineaments could be reactivated ancient fractures, producing a temporal discoloration. If tectonic, the lineaments might be still forming, with deformation only on a scale below that which we can resolve. The coloration, global pattern and collocated dark spots are consistent with recent/active alteration of the surface, given that E-ring accumulation is expected to remove intrinsic color signatures in a geologically short time

  11. PCSK6-mediated corin activation is essential for normal blood pressure.

    PubMed

    Chen, Shenghan; Cao, Pengxiu; Dong, Ningzheng; Peng, Jianhao; Zhang, Chunyi; Wang, Hao; Zhou, Tiantian; Yang, Junhua; Zhang, Yue; Martelli, Elizabeth E; Naga Prasad, Sathyamangla V; Miller, Rachel E; Malfait, Anne-Marie; Zhou, Yiqing; Wu, Qingyu

    2015-09-01

    Hypertension is the most common cardiovascular disease, afflicting >30% of adults. The cause of hypertension in most individuals remains unknown, suggesting that additional contributing factors have yet to be discovered. Corin is a serine protease that activates the natriuretic peptides, thereby regulating blood pressure. It is synthesized as a zymogen that is activated by proteolytic cleavage. CORIN variants and mutations impairing corin activation have been identified in people with hypertension and pre-eclampsia. To date, however, the identity of the protease that activates corin remains elusive. Here we show that proprotein convertase subtilisin/kexin-6 (PCSK6, also named PACE4; ref. 10) cleaves and activates corin. In cultured cells, we found that corin activation was inhibited by inhibitors of PCSK family proteases and by small interfering RNAs blocking PCSK6 expression. Conversely, PCSK6 overexpression enhanced corin activation. In addition, purified PCSK6 cleaved wild-type corin but not the R801A variant that lacks the conserved activation site. Pcsk6-knockout mice developed salt-sensitive hypertension, and corin activation and pro-atrial natriuretic peptide processing activity were undetectable in these mice. Moreover, we found that CORIN variants in individuals with hypertension and pre-eclampsia were defective in PCSK6-mediated activation. We also identified a PCSK6 mutation that impaired corin activation activity in a hypertensive patient. Our results indicate that PCSK6 is the long-sought corin activator and is important for sodium homeostasis and normal blood pressure.

  12. Retargeting R-Type Pyocins To Generate Novel Bactericidal Protein Complexes▿ †

    PubMed Central

    Williams, Steven R.; Gebhart, Dana; Martin, David W.; Scholl, Dean

    2008-01-01

    R-type pyocins are high-molecular-weight bacteriocins that resemble bacteriophage tail structures and are produced by some Pseudomonas aeruginosa strains. R-type pyocins kill by dissipating the bacterial membrane potential after binding. The high-potency, single-hit bactericidal kinetics of R-type pyocins suggest that they could be effective antimicrobials. However, the limited antibacterial spectra of natural R-type pyocins would ultimately compromise their clinical utility. The spectra of these protein complexes are determined in large part by their tail fibers. By replacing the pyocin tail fibers with tail fibers of Pseudomonas phage PS17, we changed the bactericidal specificity of R2 pyocin particles to a different subset of P. aeruginosa strains, including some resistant to PS17 phage. We further extended this idea by fusing parts of R2 tail fibers with parts of tail fibers from phages that infect other bacteria, including Escherichia coli and Yersinia pestis, changing the killing spectrum of pyocins from P. aeruginosa to the bacterial genus, species, or strain that serves as a host for the donor phage. The assembly of active R-type pyocins requires chaperones specific for the C-terminal portion of the tail fiber. Natural and retargeted R-type pyocins exhibit narrow bactericidal spectra and thus can be expected to cause little collateral damage to the healthy microbiotae and not to promote the horizontal spread of multidrug resistance among bacteria. Engineered R-type pyocins may offer a novel alternative to traditional antibiotics in some infections. PMID:18441117

  13. Subsets of Memory CD4+ T Cell and Bactericidal Antibody Response to Neisseria meningitidis Serogroup C after Immunization of HIV-Infected Children and Adolescents

    PubMed Central

    Milagres, Lucimar G.; Costa, Priscilla R.; Silva, Giselle P.; Carvalho, Karina I.; Pereira-Manfro, Wânia F.; Ferreira, Bianca; Barreto, Daniella M.; Frota, Ana Cristina C.; Hofer, Cristina B.; Kallas, Esper G.

    2014-01-01

    Meningococcal disease is endemic in Brazil, with periodic outbreaks and case fatality rates reach as high as 18 to 20% of cases. Conjugate vaccines against meningococci are immunogenic in healthy children. However, we have previously shown a poor bactericidal antibody response to a Men C conjugate vaccine in Brazilian HIV-infected children and adolescents after a single vaccine administration. The goal of the present work was to investigate associations between bactericidal antibody response induced by MenC vaccine and the frequency and activation profile (expression of CD38, HLA-DR and CCR5 molecules) of total CD4+ memory T cell sub-populations in HIV-1-infected children and adolescents. Responders to vaccination against MenC had a predominance (about 44%) of CD4+ TINTERMEDIATE subset followed by TTRANSITIONAL memory subset (23 to 26%). Importantly, CD4+ TINT frequency was positively associated with bactericidal antibody response induced by vaccination. The positive correlation persisted despite the observation that the frequency TINT CD38+HLA-DR+ was higher in responders. In contrast, CD4+ TCENTRAL MEMORY (TCM) subset negatively correlated with bactericidal antibodies. In conclusion, these data indicate that less differentiated CD+ T cells, like TCM may be constantly differentiating into intermediate and later differentiated CD4+ T cell subsets. These include CD4 TINT subset which showed a positive association with bactericidal antibodies. PMID:25532028

  14. Whole Blood Activation Results in Altered T Cell and Monocyte Cytokine Production Profiles by Flow Cytometry

    NASA Technical Reports Server (NTRS)

    Crucian, Brian E.; Sams, Clarence F.

    2001-01-01

    An excellent monitor of the immune balance of peripheral circulating cells is to determine their cytokine production patterns in response to stimuli. Using flow cytometry, a positive identification of cytokine producing cells in a mixed culture may be achieved. Recently, the ability to assess cytokine production following a whole-blood activation culture has been described. In this study, whole blood activation was compared to traditional PBMC activation and the individual cytokine secretion patterns for both T cells, T cell subsets and monocytes was determined by flow cytometry. RESULTS: For T cell cytokine assessment (IFNg/IL-10 and IL-21/L-4) following PMA +ionomycin activation: (1) a Significantly greater percentages of T cells producing IFNgamma and IL-2 were observed following whole-blood culture and (2) altered T cell cytokine production kinetics were observed by varying whole blood culture times. Four-color analysiS was used to allow assessment of cytokine production by specific T cell subsets. It was found that IFNgamma production was significantly elevated in the CD3+/CD8+ T cell population as compared to the CD3+/CD8- population following five hours of whole blood activation. Conversely, IL-2 and IL-10 production were Significantly elevated in the CD3+/CD8- T cell population as compared to the CD3+/CD8+ population. Monocyte cytokine production was assessed in both culture systems following LPS activation for 24 hours. A three-color flow cytometric was used to assess two cytokines (IL-1a/IL-12 and TNFa/IL-10) in conjunction with CD14. Nearly all monocytes were stimulated to produce IL-1a, IL-12 and TNFa. equally well in both culture systems, however monocyte production of IL-10 was significantly elevated in whole blood culture as compared to PBMC culture. IL-12 producing monocytes appeared to be a distinct subpopulation of the IL-1a producing set, whereas IL-10 and TNFa producing monocytes were largely mutually exclusive. IL-10 and TNFa producing

  15. Carbonic anhydrase activity in the red blood cells of sea level and high altitude natives.

    PubMed

    Gamboa, J; Caceda, R; Gamboa, A; Monge-C, C

    2000-01-01

    Red blood cell carbonic anhydrase (CA) activity has not been studied in high altitude natives. Because CA is an intraerythocytic enzyme and high altitude natives are polycythemic, it is important to know if the activity of CA per red cell volume is different from that of their sea level counterparts. Blood was collected from healthy subjects living in Lima (150m) and from twelve subjects from Cerro de Pasco (4330m), and hematocrit and carbonic anhydrase activity were measured. As expected, the high altitude natives had significantly higher hematocrits than the sea level controls (p = 0.0002). No difference in the CA activity per milliliter of red cells was found between the two populations. There was no correlation between the hematocrit and CA activity.

  16. Blood phagocyte activity after race training sessions in Thoroughbred and Arabian horses.

    PubMed

    Cywinska, Anna; Szarska, Ewa; Degorski, Andrzej; Guzera, Maciej; Gorecka, Renata; Strzelec, Katarzyna; Kowalik, Sylwester; Schollenberger, Antoni; Winnicka, Anna

    2013-10-01

    Intensive exercise and exertion during competition promote many changes that may result in the impairment of immunity and increased susceptibility to infections. The aim of this study was to evaluate the activity of "the first line of defense": neutrophils and monocytes in racing Thoroughbred and Arabian horses after routine training sessions. Twenty-three (12 Thoroughbred and 11 Arabian) horses were examined. Routine haematological (number of red blood cells - RBC, haemoglobin concentration - HGB, haematocrit - HCT, total number of white blood cells - WBC), biochemical (creatine phosphokinase activity - CPK and total protein concentration - TP) parameters, cortisol concentration as well as phagocytic and oxidative burst activity of neutrophils and monocytes were determined. The values of basic parameters and the activity of phagocytes differed between breeds and distinct patterns of exercise-induced changes were observed. The training sessions did not produce the decrease in phagocyte activity that might lead to the suppression of immunity.

  17. Sex and storage affect cholinesterase activity in blood plasma of Japanese quail

    USGS Publications Warehouse

    Hill, E.F.

    1989-01-01

    Freezing at -25?C had confounding effects on cholinesterase (ChE) activity in blood plasma from breeding female quail, but did not affect ChE activity in plasma from males. Plasma ChE activity of control females increased consistently during 28 days of storage while both carbamate- and cidrotophos-inhibited ChE decreased. Refrigeration of plasma at 4?C for 2 days had little effect of ChE activity. Plasma ChE activity was averaged about 34% higher in breeding males than in females. Extreme caution should be exercised in use of blood plasma for evaluation of anti ChE exposure in free-living birds.

  18. Dynamics of erythrocyte count, hemoglobin, and catalase activity in rat blood in hypokinesia, muscular activity and restoration

    NASA Technical Reports Server (NTRS)

    Taneyeva, G. V.; Potapovich, G. M.; Voloshko, N. A.; Uteshev, A. B.

    1980-01-01

    Tests were conducted to prove that muscular exertion (in this instance swimming) of different duration and intensity, as well as hypodynamia, result in an increase of hemoglobin and number of red blood cells in peripheral blood rats. Catalase activity increased with an increase in the duration of swimming, but only up to 6 hr; with 7-9 hr of swimming as well as in hypodynamia, catalase activity decreased. It was also observed that under hypodynamia as well as in 3, 5 and 6 hr exertion (swimming) the color index of blood decreased. Pressure chamber treatment (for 8 min each day for one week), alternating a 2 min negative pressure up to 35 mm Hg with 1 min positive pressure, increased the erythrocyte count and hemoglobin content.

  19. Influence of ozone on the susceptibility of Escherichia coli K1 to the bactericidal action of serum.

    PubMed

    Jankowski, S; Cisowska, A; Doroszkiewicz, W

    1996-01-01

    The susceptibility to the bactericidal action of normal bovine serum of twenty two Escherichia coli K1 strains, isolated from the urine of patients with urinary tract infections, was determined. Only four strains were resistant. Ozonization of bacterial suspensions enhanced the sensitivity of the strains to the action of both normal serum and a serum in which the alternative pathway of complement activation was thermally blocked.

  20. Molecular genetics of blood-fleshed peach reveals activation of anthocyanin biosynthesis by NAC transcription factors.

    PubMed

    Zhou, Hui; Lin-Wang, Kui; Wang, Huiliang; Gu, Chao; Dare, Andrew P; Espley, Richard V; He, Huaping; Allan, Andrew C; Han, Yuepeng

    2015-04-01

    Anthocyanin pigmentation is an important consumer trait in peach (Prunus persica). In this study, the genetic basis of the blood-flesh trait was investigated using the cultivar Dahongpao, which shows high levels of cyanidin-3-glucoside in the mesocarp. Elevation of anthocyanin levels in the flesh was correlated with the expression of an R2R3 MYB transcription factor, PpMYB10.1. However, PpMYB10.1 did not co-segregate with the blood-flesh trait. The blood-flesh trait was mapped to a 200-kb interval on peach linkage group (LG) 5. Within this interval, a gene encoding a NAC domain transcription factor (TF) was found to be highly up-regulated in blood-fleshed peaches when compared with non-red-fleshed peaches. This NAC TF, designated blood (BL), acts as a heterodimer with PpNAC1 which shows high levels of expression in fruit at late developmental stages. We show that the heterodimer of BL and PpNAC1 can activate the transcription of PpMYB10.1, resulting in anthocyanin pigmentation in tobacco. Furthermore, silencing the BL gene reduces anthocyanin pigmentation in blood-fleshed peaches. The transactivation activity of the BL-PpNAC1 heterodimer is repressed by a SQUAMOSA promoter-binding protein-like TF, PpSPL1. Low levels of PpMYB10.1 expression in fruit at early developmental stages is probably attributable to lower levels of expression of PpNAC1 plus the presence of high levels of repressors such as PpSPL1. We present a mechanism whereby BL is the key gene for the blood-flesh trait in peach via its activation of PpMYB10.1 in maturing fruit. Partner TFs such as basic helix-loop-helix proteins and NAC1 are required, as is the removal of transcriptional repressors.

  1. Globoid cell leukodystrophy (Krabbe disease): normal umbilical cord blood galactocerebrosidase activity and polymorphic mutations.

    PubMed

    Raghavan, S; Zeng, B; Torres, P A; Pastores, G M; Kolodny, E H; Kurtzberg, J; Krivit, W

    2005-01-01

    Globoid cell leukodystrophy is an inherited metabolic disorder of the central nervous system caused by deficiency of the lysosomal enzyme galactocerebrosidase. Haematopoietic stem cell transplantation is the only available effective treatment. The engraftment from normal donors provides competent cells able to correct the metabolic defect. Umbilical cord blood cells have proved to significantly decrease complications and improve engraftment rate compared to adult marrow cells in haematopoietic stem cell transplantation. Umbilical cord blood cells must be of sufficient activity to provide central nervous system recovery after engraftment is obtained. Galactocerebrosidase activity is known to be affected by two polymorphic alleles found at nucleotides 502 and 1637 of the cDNA for this gene. This enzyme activity and the polymorphic alleles noted above were analysed in 83 random samples of umbilical cord blood. The activity, assayed with the fluorogenic substrate 6-hexadecanoylamino-4-methylumbelliferyl-beta-galactopyranoside, in those with neither polymorphic allele was 4.6 +/- 1.7 units (nmol/h per mg protein). This optimal choice of cord blood was found in only 24% of specimens. Homozygotes for 1637T > C with activity of only 1.5 +/- 0.4 units represented 16% of the samples. Those heterozygous for 1637T > C with slightly better activity (2.3 +/- 0.7 units) represented 52% of the samples. Choice of umbilical cord blood for haematopoietic stem cell transplantation, therefore, requires consideration not only of cell quantity and HLA compatibility but also selection for normal alleles to obtain maximal enzymatic activity for central nervous system correction.

  2. Equilibrium physics breakdown reveals the active nature of red blood cell flickering

    NASA Astrophysics Data System (ADS)

    Turlier, Herve; Fedosov, Dmitry; Auth, Thorsten; Gov, Nir S.; Sykes, Cecile; Joanny, Jean-Francois; Gompper, Gerhard; Betz, Timo

    2015-03-01

    Red blood cell membrane flickering stimulated an abundant biological, biophysical and biochemical literature over the past 50 years. While the phenomenon has been interpreted as thermal fluctuations of the cell membrane, recent results suggest the involvement of metabolic processes. However, to date there is no direct and conclusive evidence that an active force drives membrane flickering. By comparing membrane undulations and active microrheology measurements on single human erythrocytes, we show that flickering is partly driven by an active metabolic process, as it does not satisfy the equilibrium fluctuation-dissipation relation on timescales slower than 100ms. Analytical and numerical models of the red blood cell reproduce experimental results. The analytical model assumes that membrane activity results from reversible binding of the elastic spectrin network to the lipid bilayer and predicts active fluctuations to increase with local curvature and extensional prestress in the cytoskeleton. Our mean-field calculation shows that the strength and kinetics of the binding activity regulates thereupon both passive and active mechanical properties of the red blood cell. Numerical simulations explore other possible origins of active forces on the membrane and predict coherent timescales for the molecular underlying metabolic processes.

  3. Rapid infrared determination of the potency of chlorinated bactericides.

    PubMed

    Spagnolo, F; Cestaro, J P

    1971-06-01

    A rapid infrared reflectance method for evaluating the germicidal potency of synthetic materials containing various amounts of two chlorinated bactericides was developed. The dimeric product 2,2'-methylenebis (4,6-dichlorophenol) exhibited a characteristic C=C skeletal inplane stretching infrared absorption band at 1,640 cm(-1). The monomeric 2,4-dichlorophenol precursor showed a characteristic absorption band at 1,579 cm(-1). These characteristic infrared absorptions may be used for analysis of the potency of the manufactured chlorinated bactericide. For a series of samples known to vary in dimer content, the micrograms per milliliter required for a 100% bacterial kill is first determined by a standard American Petroleum Institute method. Then the area ratio of the infrared absorption bands characteristic of the chlorinated bactericides is measured for each sample and plotted versus the microgram per milliliter required for 100% bacterial kill. The potency of subsequent samples is simply and rapidly determined by measuring this ratio from the infrared absorption curve and calculating micrograms per milliliter required for 100% kill from the calibration curve. Analysis time is approximately 1 hr compared to biocidal tests in current use requiring approximately a 1-month incubation period.

  4. Binder-block copolymer micelle interactions in bactericidal filter paper.

    PubMed

    Mansur-Azzam, Nura; Woo, Su Gyeong; Eisenberg, Adi; van de Ven, Theo G M

    2013-08-06

    We previously produced a bactericidal filter paper loaded with PAA47-b-PS214 block copolymer micelles containing the biocide triclosan (TCN), using cationic polyacryamide (cPAM) as a binder. However, we encountered a very slow filtration, resulting in long bacteria deactivation times. Slow drainage occurred only when the filter paper was left to dry. It appears that the filter paper with cPAM and micelles develops hydrophobic properties responsible for this very slow filtration. Three approaches were taken to accelerate the very slow drainage all based on modification of binder-micelle interactions: (i) keeping the micelles wet, (ii) modification of the corona, and (iii) replacing cPAM with smaller and more highly charged cationic poly(isopropanol dimethylammonium) chloride (PIDMAC). In all cases, the drainage time of bactericidal filter paper became close to that of untreated filter paper, without decreasing its efficiency. Moreover, replacing cPAM with PIDMAC led to a much more efficient bactericidal filter paper that reduced bacteria viability by more than 6 orders of magnitude. In addition to resolving the hydrophobic drainage hurdle, the three solutions also offer a better understanding of the interaction between cPAM and micelles in the filter paper.

  5. Encapsulation of titanium dioxide nanoparticles in PLA microspheres using supercritical emulsion extraction to produce bactericidal nanocomposites

    NASA Astrophysics Data System (ADS)

    Campardelli, R.; Della Porta, G.; Gomez, V.; Irusta, S.; Reverchon, E.; Santamaria, J.

    2013-10-01

    In this work, PLA microparticles containing TiO2 (anatase) nanoparticles have been produced using the Continuous Supercritical Emulsion Extraction technique (SEE-C). A stabilized anatase colloidal suspension (15 ± 5 nm) in ethanol aqueous solution was obtained by precipitation from solutions of titanium alkoxides and directly used as the water internal phase of a water-in-oil in water double emulsion or suspended as a powder in the organic phase of a solid-in-oil in water emulsion. Micro- (0.9 ± 0.5 μm) and submicro-particles (203 ± 40 nm) have been produced, with TiO2 nominal loadings of 1.2, 2.4, and 3.6 wt%. High TiO2 encapsulation efficiencies up to about 90 % have been obtained. PLA/TiO2 particles have been characterized by TEM and XPS to investigate the dispersion of the metal oxide in the polymeric matrix. The photo-assisted bactericidal activity of TiO2-containing microparticles against a biofilm-forming strain of Staphylococcus aureus was investigated in specific assays under UV light. Pure TiO2 nanoparticles and PLA/TiO2 particles showed the same bactericidal activity.

  6. Reinforcement of the bactericidal effect of ciprofloxacin on Pseudomonas aeruginosa biofilm by hyperbaric oxygen treatment.

    PubMed

    Kolpen, Mette; Mousavi, Nabi; Sams, Thomas; Bjarnsholt, Thomas; Ciofu, Oana; Moser, Claus; Kühl, Michael; Høiby, Niels; Jensen, Peter Østrup

    2016-02-01

    Chronic Pseudomonas aeruginosa lung infection is the most severe complication in cystic fibrosis patients. It is characterised by antibiotic-tolerant biofilms in the endobronchial mucus with zones of oxygen (O2) depletion mainly due to polymorphonuclear leucocyte activity. Whilst the exact mechanisms affecting antibiotic effectiveness on biofilms remain unclear, accumulating evidence suggests that the efficacy of several bactericidal antibiotics such as ciprofloxacin is enhanced by stimulation of the aerobic respiration of pathogens, and that lack of O2 increases their tolerance. Reoxygenation of O2-depleted biofilms may thus improve susceptibility to ciprofloxacin possibly by restoring aerobic respiration. We tested such a strategy using reoxygenation of O2-depleted P. aeruginosa strain PAO1 agarose-embedded biofilms by hyperbaric oxygen treatment (HBOT) (100% O2, 2.8bar), enhancing the diffusive supply for aerobic respiration during ciprofloxacin treatment. This proof-of-principle study demonstrates that biofilm reoxygenation by HBOT can significantly enhance the bactericidal activity of ciprofloxacin on P. aeruginosa. Combining ciprofloxacin treatment with HBOT thus clearly has potential to improve the treatment of P. aeruginosa biofilm infections.

  7. Bactericidal effect of lactoferrin and lactoferrin chimera against halophilic Vibrio parahaemolyticus.

    PubMed

    Leon-Sicairos, Nidia; Canizalez-Roman, Adrian; de la Garza, Mireya; Reyes-Lopez, Magda; Zazueta-Beltran, Jorge; Nazmi, Kamran; Gomez-Gil, Bruno; Bolscher, Jan G

    2009-01-01

    Infections caused by Vibrio parahaemolyticus, an halophilic member of the genus Vibrio, have increased globally in the last 5 years. Diarrhea caused by V. parahaemolyticus results from eating raw or undercooked seafood. The aim of this work was to investigate whether lactoferrin and some lactoferrin-peptides have bactericidal activity against Vibrio parahaemolyticus ATCC 17802, the pandemic strain O3:K6, and the multidrug resistant isolate 727, as well as against Vibrio cholerae strains O1 and non-O1. Whereas both peptides lactoferricin (17-30) and lactoferrampin (265-284) did not have bactericidal activity, 40 microM of lactoferrin chimera (a fusion of the two peptides) inhibited the growth of all Vibrio tested to the same extent as the antibiotic gentamicin. The cidal effect of LFchimera showed a clear concentration response in contrast to bovine lactoferrin which showed higher inhibition at 10 microM than at 40 microM. FITC-labeled LFchimera bound to the bacterial membranes. Moreover LFchimera permeabilized bacterial cells and membranes were seriously damaged. Finally, in experiments with the multidrug resistant isolate 727, sub-lethal doses of LFchimera strongly reduced the concentrations of ampicillin, gentamicin or kanamicin needed to reach more than 95% growth inhibition, suggesting synergistic effects. These data indicate that LFchimera is a potential candidate to combat the multidrug resistant pathogenic Vibrio species.

  8. Bactericidal kinetics of 3 lactoferricins against Staphylococcus aureus and Escherichia coli.

    PubMed

    Ulvatne, H; Vorland, L H

    2001-01-01

    Bovine lactoferricin is an antimicrobial, cationic peptide generated upon gastric pepsin cleavage of bovine lactoferrin. We investigated the bactericidal effects of native lactoferricin [Lfcin B(17-41)], a shortened derivative [Lfcin B(17-31)] and the all-D-amino acid counterpart of Lfcin B(17-31) against Escherichia coli and Staphylococcus aureus. The results revealed different activities for the peptides against Gram-positive and -negative bacteria. D-Lfcin B(17-31) was the most efficient peptide against E. coli. The same peptide showed improved activity against S. aureus, D-Lfcin B(17-31) showed a significant better efficacy when compared to the L-form, but not when compared to Lfcin B(17-41). There was no correlation between the bactericidal concentrations and the time needed to achieve maximum effect. This indicates the importance of structural differences between the peptides and/or bacteria and implies that the simple thesis of I antibacterial target is not valid for lactoferricin.

  9. Synergistic effect of proanthocyanidin on the bactericidal action of the photolysis of H2O2.

    PubMed

    Ikai, Hiroyo; Nakamura, Keisuke; Kanno, Taro; Shirato, Midori; Meirelles, Luiz; Sasaki, Keiichi; Niwano, Yoshimi

    2013-01-01

    The in vitro antibacterial activity of the hydroxyl radical generation system by the photolysis of H2O2 in combination with proanthocyanidin, which refers to a group of polyphenolic compounds, was examined. Bactericidal activity of photo-irradiated H2O2 at 405 nm against Streptococcus mutans, a major pathogen of dental caries, was augmented in the presence of proanthocyanidin, whose bactericidal effect by itself was very poor, in a concentration-dependent manner. This combination was also proven effective against Porphyromonas gingivalis, a major pathogen of periodontitis. It is speculated that H2O2, generated from photo-irradiated proanthocyanidin around the bacterial cells, is photolyzed to the hydroxyl radical, which would in turn affect the membrane structure and function of the bacterial cells, resulting in augmented sensitivity of bacterial cells to the disinfection system utilizing the photolysis of H2O2. The present study suggests that the combination of H2O2 and proanthocyanidin works synergistically to kill bacteria when photo-irradiated.

  10. Anti-bactericidal properties of stingray Dasyatis pastinaca groups V, IIA, and IB phospholipases A2: a comparative study.

    PubMed

    Bacha, Abir Ben

    2014-10-01

    Group IIA secreted phospholipase A2 (group IIA sPLA2) is known to display potent Gram-positive bactericidal activity in vitro and in vivo. We have analyzed the bactericidal activity of the full set of native stingray and dromedary groups V, IIA, and IB sPLA2s on several Gram-positive and Gram-negative strains. The rank order potency among both marine and mammal sPLA2s against Gram-positive bacteria is group IIA > V > IB, whereas Gram-negative bacteria exhibited a much higher resistance. There is a synergic action of the sPLA2 with lysozyme when added to the bacteria culture prior to sPLA2.The bactericidal efficiency of groups V and IIA sPLA2s was shown to be dependent upon the presence of calcium ions and to a less extent Mg(2+) ions and then a correlation could be made to its hydrolytic activity of membrane phospholipids. Importantly, we showed that stingray and dromedary groups V, IIA, and IB sPLA2s present no cytotoxicity after their incubation with MDA-MB-231cells. stingray groups V and IIA sPLA2s, like mammal ones, may be considered as future therapeutic agents against bacterial infections.

  11. Blood group ABO and Lewis antigens in bladder tumors: correlation between glycosyltransferase activity and antigen expression.

    PubMed

    Orntoft, T F; Wolf, H

    1988-01-01

    Pronounced changes in the expression of ABO and Lewis antigens have been observed in transitional cell carcinomas compared with normal urothelium. These changes are associated with changes in the activity of blood-group gene-encoded glycosyltransferases. This paper describes the correlation between blood-group antigen expression and the activity of glycosyltransferases in transitional cell carcinomas. Examined individuals were A1A2BO, Lewis, and secretor typed by the use of blood and saliva. The activity of alpha-2-, and alpha-4-L-fucosyltransferases as well as the alpha-3-N-acetyl-D-galactosaminyltransferase were determined as p-moles of labelled sugar incorporated by Lacto-N-biose I and 2'-fucosyllactose, respectively, per 100,000 carcinoma cells. In 3 non-secretors whose erythrocytes types as Le(a+b-), the alpha-2-L-fucosyltransferase activity was similar to that in 3 secretors, and the Leb antigen could be demonstrated to be present by monoclonal antibodies, both by immunohistological and immunochemical means. In 11 tumors from A individuals, the A1-transferase was severely reduced in 9 individuals who showed a loss of A antigen expression, and present in 2 individuals with A antigen expression in cytoplasmic vesicles. In conclusion, we demonstrate a good correlation between individual glycosyltransferase activity and expression of blood group Leb and loss of expression of blood group A in transitional cell carcinomas. Immunostaining of neutral glycolipids separated by TLC showed the Leb-active glycolipids to be simple hexa-saccharides in both secretors and non-secretors.

  12. δ-Aminolevulinic acid dehydrase activity in the blood of men working with lead alkyls

    PubMed Central

    Millar, J. A.; Thompson, G. G.; Goldberg, A.; Barry, P. S. I.; Lowe, E. H.

    1972-01-01

    Millar, J. A., Thompson, G. G., Goldberg, A., Barry, P. S. I., and Lowe, E. H. (1972).Brit. J. industr. Med.,29, 317-320. δ-Aminolevulinic acid dehydrase activity in the blood of men working with lead alkyls. The activity of erythrocyte ALA1-dehydrase is inhibited in vivo at blood lead (Pb2+) levels within the upper range of normal (20-40 μg/100 ml) and in vitro at lead concentrations greater than 10-7 M. In view of the high sensitivity of the enzyme to Pb2+, the levels of enzyme activity in the blood of men occupationally exposed to lead alkyls, particularly tetraethyllead, were measured. It was found that the enzyme activity in an exposed group of men was significantly less (P<0·001) than in a control group, the respective mean values being 220 and 677 units of enzyme activity. Tetraethyllead is metabolized in the body via triethyllead and diethyllead ions. As the latter compound possesses properties similar to Pb2+, it was synthesized in the laboratory and its effect on ALA-dehydrase was studied. Diethyllead ion was found to inhibit ALA-dehydrase activity at concentrations greater than 5 x 10-5 M, although the degree of inhibition was less than that obtained with Pb2+. These results suggest that exposure to tetraethyllead can cause a decrease in erythrocyte ALA-dehydrase activity. PMID:5044603

  13. Ozone-induced elevation of creatine kinase activity in blood plasma of rats

    SciTech Connect

    Veninga, T.S.; Fidler, V.

    1986-10-01

    Rats exposed to three different low concentrations of ozone for 2 hr show alterations in blood plasma creatinine kinase activity comparable to those previously observed in mice. The reactions are explained as compensatory, possibly being involved in the initial phase of adaptation development.

  14. Circulating plasma cholesteryl ester transfer protein activity and blood pressure tracking in the community

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Clinical trials using cholesteryl ester transfer protein (CETP) inhibitors to raise high-density lipoprotein cholesterol (HDL-C) concentrations reported an 'off-target' blood pressure (BP) raising effect. We evaluated the relations of baseline plasma CETP activity and longitudinal BP change. One tho...

  15. A Kinesthetic Activity Using LEGO Bricks and Buckets for Illustrating the Regulation of Blood Sugar

    ERIC Educational Resources Information Center

    Urschler, Margaret; Meidl, Katherine; Browning, Samantha; Khan, Basima; Milanick, Mark

    2015-01-01

    This article describes how, when first faced with understanding blood sugar regulation, students often resort to simple memorization.Many students would like to get more involved with the conceptual framework but do not know how to start. The authors have developed an activity based on the Modell approach, a "view from the inside." This…

  16. Proteolytic activity of IgGs from blood serum of Wistar rats at experimental rheumatoid arthritis.

    PubMed

    Kit, Yu Ya; Myronovsky, S L; Kril, I I; Havrylyuk, A M; Chop'yak, V V; Stoika, R S

    2014-01-01

    The aim of this work was to study the proteolytic activity of IgGs purified from blood serum of Wistar rats at experimental rheumatoid arthritis (ERA) induced by an injection of bovine collagen of type II. Twenty rats were immunized with a preparation of bovine collagen II (Sigma-Aldrich, USA) in the presence of complete Freund's adjuvant. ERA development was determined by inflammation in limbs of treated animals. IgG preparations were isolated from blood serum of immunized and non-immunized animals by precipitation of antibodies with 33% ammonium sulfate followed by chromatography on the Protein G-Sepharose column. Human histone H1, bovine collagen II, calf thymus histones, myelin basic protein (MBP), bovine serum albumin (BSA), and bovine casein were used as substrates of the proteolytic activity of IgGs. It was found that IgG preparations from blood serum of rats with ERA were capable of cleaving histone H1 and MBP, however, they were catalytically inactive towards collagen II, casein, BSA, and core histones. IgGs from blood serum of non-immunized rats were proteolytically inactive towards all used protein substrates. Thus, we demonstrated that immunization of rats with bovine collagen II induced IgG-antibodies possessing the proteolytic activity towards histone H1 and MBP. This activity might be associated with the development of inflammatory processes in the immunized rats.

  17. Arginase activity in peripheral blood of patients with intestinal schistosomiasis, Wonji, Central Ethiopia.

    PubMed

    Getaneh, A; Tamrat, A; Tadesse, K

    2015-07-01

    Morbidity and mortality caused by schistosomiasis usually results from immunopathology. But the underlying mechanisms are not yet clearly understood. Th2-type immune response is thought to be dominant during chronic schistosomiasis, and upregulation of arginase-I is one component of this milieu. A cohort study was conducted to assess arginase activity in peripheral blood of humans with intestinal schistosomiasis in Wonji-Shoa Sugar Estate, Central Ethiopia. Laboratory-confirmed 30 Schistosoma mansoni-infected patients and 18 apparently healthy controls were recruited. Faecal egg count was carried out by Kato-Katz technique. Plasma and peripheral blood mononuclear cells (PBMCs) were isolated from whole blood. Activity of arginase in plasma and PBMC lysates was measured, and results were compared with that of controls. Twenty-one of 30 patients had light infection, whereas moderate and heavy intensity infections were observed in eight and only one patient(s), respectively. A significant increase in both PBMC (patients: 59.96 + 82.99, controls: 25.44 + 24.6 mU/mg protein, P < 0.0001) and plasma (patients: 1.61 + 2.19, controls: 0.31 + 0.73 mU/mL plasma, P < 0.0001) arginase activity was observed during human S. mansoni infection. Arginase activity increases in peripheral blood of patients with intestinal schistosomiasis.

  18. [Oxidative modification of proteins and antioxidative blood activity of ground squirrels during induced awakening from winter sleep].

    PubMed

    Astaeva, M D; Klichkhanov, N K

    2009-01-01

    The intensity of oxidative modification of plasma proteins and activity of the antioxidative system of the blood of the ground squirrels during awakening from winter sleep is studied. During waking of animals, processes of oxidative modification of proteins in the blood plasma intensify. While the body temperature rises, the antioxidative activity of hydrophylic components of the blood plasma grows essentially, and erythrocyte superoxide dismutase too. Activity of erythrocyte catalase at all stages of waking is definitely higher than in the control. The received results evidence that the high activity of various links of antioxidative blood protection provides stability to oxidative stress during waking of animals from deep sleep.

  19. Inhibition of pseudoperoxiadse activity of human red blood cell hemoglobin by methocarbamol.

    PubMed

    Minai-Tehrani, Dariush; Toofani, Sara; Yazdi, Fatemeh; Minai-Tehrani, Arash; Mollasalehi, Hamidreza; Bakhtiari Ziabari, Kourosh

    2017-01-01

    After red blood cells lysis, hemoglobin is released to blood circulation. Hemoglobin is carried in blood by binding to haptoglobin. In normal individuals, no free hemoglobin is observed in the blood, because most of the hemoglobin is in the form of haptoglobin complex. In some diseases that are accompanied by hemolysis, the amount of released hemoglobin is higher than its complementary haptoglobin. As a result, free hemoglobin appears in the blood, which is a toxic compound for these patients and may cause renal failure, hypertensive response and risk of atherogenesis. Free hemoglobin has been determined to have peroxidase activity and considered a pseudoenzyme. In this study, the effect of methocarbamol on the peroxidase activity of human hemoglobin was investigated. Our results showed that the drug inhibited the pseudoenzyme by un-competitive inhibition. Both Km and Vmax decreased by increasing the drug concentration. Ki and IC50 values were determined as 6 and 10mM, respectively. Docking results demonstrated that methocarbamol did not attach to heme group directly. A hydrogen bond linked NH2 of carbamate group of methocarbamol to the carboxyl group of Asp126 side chain. Two other hydrogen bonds could be also observed between hydroxyl group of the drug and Ser102 and Ser133 residues of the pseudoenzyme.

  20. Comparative investigation of antioxidant activity of human serum blood by amperometric, voltammetric and chemiluminescent methods

    PubMed Central

    Korotkova, Elena; Voronova, Olesya; Sazhina, Natalia; Petrova, Ekatherina; Artamonov, Anton; Chernyavskaya, Ludmila; Dorozhko, Elena

    2015-01-01

    Introduction A blood test can provide important information about the functional state of the antioxidant system. Malfunction of this system increases the concentration of free radicals and can cause oxidative stress. A difficulty in assessing oxidative stress is the lack of a universal method for determining the antioxidant activity (AOA) of blood components, because of their different nature. Material and methods The objects of investigation were sera of 30 male patients with a diagnosis of alcohol dependence syndrome and healthy donors. Comparative investigation of total antioxidant activity (TAA) of human serum blood was carried out by voltammetric (VA), amperometric (AM) and chemiluminescent (HL) methods. Results All applied methods revealed that serum TAA of the patients with alcoholism is lower than TAA of healthy donors (control group); according to amperometric method the average value of serum TAA was 850 ±210 nA × s, and 660 ±150 nA × s for healthy donors and alcoholics respectively (p < 0.05). Similar trend was revealed by chemiluminescence and voltammetry methods. The results confirm that thiol compounds make a significant contribution to the antioxidant activity of serum. The average thiol concentrations were 0.94 ±0.34 mmol/l and 1.21 ±0.36 mmol/l (p < 0.05) for alcoholics and healthy donors respectively. Decreasing thiol concentration in blood of alcoholics leads to depletion of antioxidant systems of blood. However, the differences between the results of AM, VA and HL methods were significant, because they reflected different aspects of antioxidant activity. Conclusions For objective assessment of antioxidant activity of biological objects, we suggest using methods based on different model systems. PMID:27695499

  1. Elevated blood plasma concentrations of active ghrelin and obestatin in benign ovarian neoplasms and ovarian cancers.

    PubMed

    Markowska, A; Ziółkowska, A; Jaszczyńska-Nowinka, K; Madry, R; Malendowicz, L K

    2009-01-01

    Both ghrelin and obestatin are derived from preproghrelin by post-translational processing. The two peptides are secreted into the blood but circulating levels of these peptides have not been assessed in women with ovarian tumours. Therefore, the purpose of this study was to evaluate peripheral blood concentrations of active and total ghrelin and obestatin in patients with benign ovarian tumours and those with ovarian cancer. The studies were conducted on 22 patients operated due to benign ovarian tumours, and 31 patients operated due to ovarian cancer. A control group consisted of 32 women, 24 to 65 years of age. Both in women with benign ovarian tumours and those with ovarian cancer blood concentrations of active ghrelin and obestatin were higher than in the control group (active ghrelin: 90 +/- 4, 84 +/- 4 and 56 +/- 9 pg/ml, respectively, obestatin: 660 +/- 36; 630 +/- 30 and 538 +/- 31 ng/ml (x +/- SE), respectively). In contrast, total ghrelin concentrations in blood were similar in the studied groups. The alterations resulted in increased values of active to total ghrelin concentration ratio in the peripheral blood of patients with benign ovarian tumours or with ovarian cancer (0.79 +/- 0.02 and 0.93 +/- 0.05, respectively vs 0.58 +/- 0.02 in the control group). Due to the absence of any convincing proof for the presence of a functional GHS-R-1a receptor for ghrelin in human ovaries it did not seem probable that the observed elevated levels of active ghrelin and obestatin were directly linked to development of ovarian tumours.

  2. Anopheles Midgut Epithelium Evades Human Complement Activity by Capturing Factor H from the Blood Meal

    PubMed Central

    Khattab, Ayman; Barroso, Marta; Miettinen, Tiera; Meri, Seppo

    2015-01-01

    Hematophagous vectors strictly require ingesting blood from their hosts to complete their life cycles. Exposure of the alimentary canal of these vectors to the host immune effectors necessitates efficient counteractive measures by hematophagous vectors. The Anopheles mosquito transmitting the malaria parasite is an example of hematophagous vectors that within seconds can ingest human blood double its weight. The innate immune defense mechanisms, like the complement system, in the human blood should thereby immediately react against foreign cells in the mosquito midgut. A prerequisite for complement activation is that the target cells lack complement regulators on their surfaces. In this work, we analyzed whether human complement is active in the mosquito midgut, and how the mosquito midgut cells protect themselves against complement attack. We found that complement remained active for a considerable time and was able to kill microbes within the mosquito midgut. However, the Anopheles mosquito midgut cells were not injured. These cells were found to protect themselves by capturing factor H, the main soluble inhibitor of the alternative complement pathway. Factor H inhibited complement on the midgut cells by promoting inactivation of C3b to iC3b and preventing the activity of the alternative pathway amplification C3 convertase enzyme. An interference of the FH regulatory activity by monoclonal antibodies, carried to the midgut via blood, resulted in increased mosquito mortality and reduced fecundity. By using a ligand blotting assay, a putative mosquito midgut FH receptor could be detected. Thereby, we have identified a novel mechanism whereby mosquitoes can tolerate human blood. PMID:25679788

  3. Blood flow, sympathetic activity and pain relief following lumbar sympathetic blockade or surgical sympathectomy.

    PubMed

    Walsh, J A; Glynn, C J; Cousins, M J; Basedow, R W

    1985-02-01

    The physiological effects of local anaesthetic (bupivacaine), neurolytic (phenol) blockade and surgical ablation of the lumbar sympathetic chain were assessed in patients with peripheral vascular disease or sympathetic dystrophy. Local anaesthetic blockade in 49 patients resulted in significant decrease in pain, plantar sweating and in the vasoconstrictor ice response of the foot, as well as a significant increase in skin temperature and foot blood flow. Subsequent neurolytic blockade in 31 of these patients achieved an effective denervation as assessed by the same physiological measurements. The magnitude of changes in blood flow and sympathetic activity were similar for local anaesthetic and neurolytic blockade as well as in six patients who underwent surgical sympathectomy.

  4. Non-selective voltage-activated cation channel in the human red blood cell membrane.

    PubMed

    Kaestner, L; Bollensdorff, C; Bernhardt, I

    1999-02-04

    Using the patch-clamp technique, a non-selective voltage-activated Na+ and K+ channel in the human red blood cell membrane was found. The channel operates only at positive membrane potentials from about +30 mV (inside positive) onwards. For sodium and potassium ions, similar conductances of about 21 pS were determined. Together with the recently described K+(Na+)/H+ exchanger, this channel is responsible for the increase of residual K+ and Na+ fluxes across the human red blood cell membrane when the cells are suspended in low ionic strength medium.

  5. Bactericidal efficacy of atmospheric pressure non-thermal plasma (APNTP) against the ESKAPE pathogens.

    PubMed

    Flynn, Padrig B; Higginbotham, Sarah; Alshraiedeh, Nid'a H; Gorman, Sean P; Graham, William G; Gilmore, Brendan F

    2015-07-01

    The emergence of multidrug-resistant pathogens within the clinical environment is presenting a mounting problem in hospitals worldwide. The 'ESKAPE' pathogens (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa and Enterobacter spp.) have been highlighted as a group of causative organisms in a majority of nosocomial infections, presenting a serious health risk due to widespread antimicrobial resistance. The stagnating pipeline of new antibiotics requires alternative approaches to the control and treatment of nosocomial infections. Atmospheric pressure non-thermal plasma (APNTP) is attracting growing interest as an alternative infection control approach within the clinical setting. This study presents a comprehensive bactericidal assessment of an in-house-designed APNTP jet both against biofilms and planktonic bacteria of the ESKAPE pathogens. Standard plate counts and the XTT metabolic assay were used to evaluate the antibacterial effect of APNTP, with both methods demonstrating comparable eradication times. APNTP exhibited rapid antimicrobial activity against all of the ESKAPE pathogens in the planktonic mode of growth and provided efficient and complete eradication of ESKAPE pathogens in the biofilm mode of growth within 360s, with the exception of A. baumannii where a >4log reduction in biofilm viability was observed. This demonstrates its effectiveness as a bactericidal treatment against these pathogens and further highlights its potential application in the clinical environment for the control of highly antimicrobial-resistant pathogens.

  6. Blood thioredoxin reductase activity, oxidative stress and hematological parameters in painters and battery workers: relationship with lead and cadmium levels in blood.

    PubMed

    Conterato, Greicy M M; Bulcão, Rachel P; Sobieski, Rocheli; Moro, Angela M; Charão, Mariele F; de Freitas, Fernando A; de Almeida, Fernanda L; Moreira, Ana P L; Roehrs, Miguel; Tonello, Raquel; Batista, Bruno L; Grotto, Denise; Barbosa, Fernando; Garcia, Solange C; Emanuelli, Tatiana

    2013-02-01

    Oxidative stress has been shown to be involved in lead and cadmium toxicity. We recently showed that the activity of the antioxidant enzyme thioredoxin reductase (TrxR) is increased in the kidneys of lead-exposed rats. The present study evaluated the blood cadmium and blood lead levels (BLLs) and their relationship with hematological and oxidative stress parameters, including blood TrxR activity in 50 painters, 23 battery workers and 36 control subjects. Erythrocyte δ-aminolevulinate dehydratase (δ-ALA-D) activity and its reactivation index were measured as biomarkers of lead effects. BLLs increased in painters, but were even higher in the battery workers group. In turn, blood cadmium levels increased only in the painters group, whose levels were higher than the recommended limit. δ-ALA-D activity was inhibited only in battery workers, whereas the δ-ALA-D reactivation index increased in both exposed groups; both parameters were correlated to BLLs (r = -0.59 and 0.84, P < 0.05), whereas the reactivation index was also correlated to blood cadmium levels (r = 0.27, P < 0.05). The changes in oxidative stress and hematological parameters were distinctively associated with either BLLs or blood cadmium levels, except glutathione-S-transferase activity, which was correlated with both lead (r = 0.34) and cadmium (r = 0.47; P < 0.05). However, TrxR activity did not correlate with any of the metals evaluated. In conclusion, blood TrxR activity does not seem to be a good parameter to evaluate oxidative stress in lead- and cadmium-exposed populations. However, lead-associated changes in biochemical and hematological parameters at low BLLs underlie the necessity of re-evaluating the recommended health-based limits in occupational exposure to this metal.

  7. Mechanism of platelet activation induced by endocannabinoids in blood and plasma.

    PubMed

    Brantl, S Annette; Khandoga, Anna L; Siess, Wolfgang

    2014-01-01

    Platelets play a central role in atherosclerosis and atherothrombosis, and circulating endocannabinoids might modulate platelet function. Previous studies concerning effects of anandamide (N-arachidonylethanolamide) and 2-arachidonoylglycerol (2-AG) on platelets, mainly performed on isolated cells, provided conflicting results. We therefore investigated the action of three main endocannabinoids [anandamide, 2-AG and virodhamine (arachidonoylethanolamine)] on human platelets in blood and platelet-rich plasma (PRP). 2-AG and virodhamine induced platelet aggregation in blood, and shape change, aggregation and adenosine triphosphate (ATP) secretion in PRP. The EC50 of 2-AG and virodhamine for platelet aggregation in blood was 97 and 160 µM, respectively. Lower concentrations of 2-AG (20 µM) and virodhamine (50 µM) synergistically induced aggregation with other platelet stimuli. Platelet activation induced by 2-AG and virodhamine resembled arachidonic acid (AA)-induced aggregation: shape change, the first platelet response, ATP secretion and aggregation induced by 2-AG and virodhamine were all blocked by acetylsalicylic acid (ASA) or the specific thromboxane A2 (TXA2) antagonist daltroban. In addition, platelet activation induced by 2-AG and virodhamine in blood and PRP were inhibited by JZL184, a selective inhibitor of monoacylglycerol lipase (MAGL). In contrast to 2-AG and virodhamine, anandamide, a substrate of fatty acid amidohydrolase, was inactive. Synthetic cannabinoid receptor subtype 1 (CB1) and 2 (CB2) agonists lacked stimulatory as well as inhibitory platelet activity. We conclude that 2-AG and virodhamine stimulate platelets in blood and PRP by a MAGL-triggered mechanism leading to free AA and its metabolism by platelet cyclooxygenase-1/thromboxane synthase to TXA2. CB1, CB2 or non-CB1/CB2 receptors are not involved. Our results imply that ASA and MAGL inhibitors will protect platelets from activation by high endocannabinoid levels, and that

  8. The minimizing of fluorescence background in Raman optical activity and Raman spectra of human blood plasma.

    PubMed

    Tatarkovič, Michal; Synytsya, Alla; Šťovíčková, Lucie; Bunganič, Bohuš; Miškovičová, Michaela; Petruželka, Luboš; Setnička, Vladimír

    2015-02-01

    Raman optical activity (ROA) is inherently sensitive to the secondary structure of biomolecules, which makes it a method of interest for finding new approaches to clinical applications based on blood plasma analysis, for instance the diagnostics of several protein-misfolding diseases. Unfortunately, real blood plasma exhibits strong background fluorescence when excited at 532 nm; hence, measuring the ROA spectra appears to be impossible. Therefore, we established a suitable method using a combination of kinetic quenchers, filtering, photobleaching, and a mathematical correction of residual fluorescence. Our method reduced the background fluorescence approximately by 90%, which allowed speedup for each measurement by an average of 50%. In addition, the signal-to-noise ratio was significantly increased, while the baseline distortion remained low. We assume that our method is suitable for the investigation of human blood plasma by ROA and may lead to the development of a new tool for clinical diagnostics.

  9. Carbon nanotubes activate store-operated calcium entry in human blood platelets.

    PubMed

    Lacerda, Silvia H De Paoli; Semberova, Jana; Holada, Karel; Simakova, Olga; Hudson, Steven D; Simak, Jan

    2011-07-26

    Carbon nanotubes (CNTs) are known to potentiate arterial thrombosis in animal models, which raises serious safety issues concerning environmental or occupational exposure to CNTs and their use in various biomedical applications. We have shown previously that different CNTs, but not fullerene (nC60), induce the aggregation of human blood platelets. To date, however, a mechanism of potentially thrombogenic CNT-induced platelet activation has not been elucidated. Here we show that pristine multiwalled CNTs (MWCNTs) penetrate platelet plasma membrane without any discernible damage but interact with the dense tubular system (DTS) causing depletion of platelet intracellular Ca(2+) stores. This process is accompanied by the clustering of stromal interaction molecule 1 (STIM1) colocalized with Orai1, indicating the activation of store-operated Ca(2+) entry (SOCE). Our findings reveal the molecular mechanism of CNT-induced platelet activation which is critical in the evaluation of the biocompatibility of carbon nanomaterials with blood.

  10. An Engineered R-Type Pyocin Is a Highly Specific and Sensitive Bactericidal Agent for the Food-Borne Pathogen Escherichia coli O157:H7

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Some strains of Pseudomonas aeruginosa produce R-type pyocins, which are high molecular weight phage tail-like protein complexes that have bactericidal activity against other Pseudomonas strains. These particles recognize and bind to bacterial surface structures via tail fibers; their primary spectr...

  11. Strength training reduces arterial blood pressure but not sympathetic neural activity in young normotensive subjects

    NASA Technical Reports Server (NTRS)

    Carter, Jason R.; Ray, Chester A.; Downs, Emily M.; Cooke, William H.

    2003-01-01

    The effects of resistance training on arterial blood pressure and muscle sympathetic nerve activity (MSNA) at rest have not been established. Although endurance training is commonly recommended to lower arterial blood pressure, it is not known whether similar adaptations occur with resistance training. Therefore, we tested the hypothesis that whole body resistance training reduces arterial blood pressure at rest, with concomitant reductions in MSNA. Twelve young [21 +/- 0.3 (SE) yr] subjects underwent a program of whole body resistance training 3 days/wk for 8 wk. Resting arterial blood pressure (n = 12; automated sphygmomanometer) and MSNA (n = 8; peroneal nerve microneurography) were measured during a 5-min period of supine rest before and after exercise training. Thirteen additional young (21 +/- 0.8 yr) subjects served as controls. Resistance training significantly increased one-repetition maximum values in all trained muscle groups (P < 0.001), and it significantly decreased systolic (130 +/- 3 to 121 +/- 2 mmHg; P = 0.01), diastolic (69 +/- 3 to 61 +/- 2 mmHg; P = 0.04), and mean (89 +/- 2 to 81 +/- 2 mmHg; P = 0.01) arterial blood pressures at rest. Resistance training did not affect MSNA or heart rate. Arterial blood pressures and MSNA were unchanged, but heart rate increased after 8 wk of relative inactivity for subjects in the control group (61 +/- 2 to 67 +/- 3 beats/min; P = 0.01). These results indicate that whole body resistance exercise training might decrease the risk for development of cardiovascular disease by lowering arterial blood pressure but that reductions of pressure are not coupled to resistance exercise-induced decreases of sympathetic tone.

  12. Isolation of dendritic cells from umbilical cord blood using magnetic activated cell sorting or adherence.

    PubMed

    Bie, Yachun; Xu, Qiuxiang; Zhang, Zhenyu

    2015-07-01

    Dendritic cells (DCs) are a highly specialized type of antigen-presenting cell. The present study describes and compares two methods for preparing DCs from umbilical cord blood. The first method involves the isolation of DCs by magnetic activated cell sorting (MACS). This technique isolates CD34(+) cells from cord blood and induces the formation of DCs by the addition of cytokines, granulocyte macrophage colony-stimulating factor and interleukin-4. The second method involves the generation of large numbers of DCs from cord blood using an adherent method, which isolates umbilical cord blood mononuclear cells and induces DCs in the same conditions as those used in MACS. The DCs were harvested following 7 days of incubation and observed with an inverted microscope. The phenotype of the cells was then analyzed by flow cytometry. The results revealed that, subsequent to 7 days of incubation, the differentiated DCs obtained using the adherent method were more mature than those isolated using MACS. However, these cells were unable to be maintained in culture for more than 9-10 days. By contrast, the DCs derived from CD34(+) cells by MACS were phenotypically stable and could be maintained for up to 3 weeks in culture. Either method produced DCs from cord blood. However, the DCs isolated using the MACS method demonstrated higher homogeneity, yield and viability than those obtained using the adherent method. Due to the various compositions of the monocyte subsets isolated, isolation methods affect the phenotypes and functions of the resultant DCs.

  13. Evaluation of a commercial radiochromatography module as an arterial blood activity monitor.

    PubMed

    Laymon, C M; Sashin, D; Carney, J P; Ruszkiewicz, J; Altenburger, D; Becker, C R; Lopresti, B J; Mason, N S; Mountz, J M; Price, J C; Schavey, R; Mathis, C A

    2008-01-21

    Input functions required for positron emission tomography (PET) tracer kinetic modeling are often obtained from arterial blood. In some situations, using short-lived radiotracers, e.g. [(15)O]water, rapid sample handling is required. A method used at several facilities is to pump blood through a detector system at a constant rate. We investigate the suitability of a commercial radiochromatography module (IN/US Posi-RAM) for this new use. The Posi-RAM consists of two 2.5 cm (length) x 2.5 cm (diameter) cylindrical bismuth germanate (BGO) detectors that can operate in coincidence mode. Arterial blood is transported through the system via a length of tubing with flow rate controlled by a peristalsis pump. A custom-counting loop and support frame were designed for the Posi-RAM for PET studies. System sensitivity was determined to be 1.1 x 10(4) cps/(MBq ml(-1)). Dead time as a function of count-rate was found to be less than 1% for concentrations below 3.5 MBq ml(-1), a range encompassing all human-study values. In a human study, the performance of the device was found to be similar to that of the facility's current blood monitor (Siemens Fluid Monitor). We conclude that the Posi-RAM has the necessary sensitivity and count-rate capabilities to be used as a real-time blood activity monitor.

  14. Evaluation of a commercial radiochromatography module as an arterial blood activity monitor

    NASA Astrophysics Data System (ADS)

    Laymon, C. M.; Sashin, D.; Carney, J. P.; Ruszkiewicz, J.; Altenburger, D.; Becker, C. R.; Lopresti, B. J.; Mason, N. S.; Mountz, J. M.; Price, J. C.; Schavey, R.; Mathis, C. A.

    2008-01-01

    Input functions required for positron emission tomography (PET) tracer kinetic modeling are often obtained from arterial blood. In some situations, using short-lived radiotracers, e.g. [15O]water, rapid sample handling is required. A method used at several facilities is to pump blood through a detector system at a constant rate. We investigate the suitability of a commercial radiochromatography module (IN/US Posi-RAM) for this new use. The Posi-RAM consists of two 2.5 cm (length) × 2.5 cm (diameter) cylindrical bismuth germanate (BGO) detectors that can operate in coincidence mode. Arterial blood is transported through the system via a length of tubing with flow rate controlled by a peristalsis pump. A custom-counting loop and support frame were designed for the Posi-RAM for PET studies. System sensitivity was determined to be 1.1 × 104 cps/(MBq ml-1). Dead time as a function of count-rate was found to be less than 1% for concentrations below 3.5 MBq ml-1, a range encompassing all human-study values. In a human study, the performance of the device was found to be similar to that of the facility's current blood monitor (Siemens Fluid Monitor). We conclude that the Posi-RAM has the necessary sensitivity and count-rate capabilities to be used as a real-time blood activity monitor.

  15. Blood pressure lowering, fibrinolysis enhancing and antioxidant activities of cardamom (Elettaria cardamomum).

    PubMed

    Verma, S K; Jain, Vartika; Katewa, S S

    2009-12-01

    Elettaria cardamomum (L.) Maton. (Small cardamom) fruit powder was evaluated for its antihypertensive potential and its effect on some of the cardiovascular risk factors in individuals with stage 1 hypertension. Twenty, newly diagnosed individuals with primary hypertension of stage 1 were administered 3 g of cardamom powder in two divided doses for 12 weeks. Blood pressure was recorded initially and at 4 weeks interval for 3 months. Blood samples were also collected initially and at 4 weeks interval for estimation of lipid profile, fibrinogen and fibrinolysis. Total antioxidant status, however, was assessed initially and at the end of the study. Administration of 3 g cardamom powder significantly (p<0.001) decreased systolic, diastolic and mean blood pressure and significantly (p<0.05) increased fibrinolytic activity at the end of 12th week. Total antioxidant status was also significantly (p<0.05) increased by 90% at the end of 3 months. However, fibrinogen and lipid levels were not significantly altered. All study subjects experienced a feeling of well being without any side-effects. Thus, the present study demonstrates that small cardamom effectively reduces blood pressure, enhances fibrinolysis and improves antioxidant status, without significantly altering blood lipids and fibrinogen levels in stage 1 hypertensive individuals.

  16. PCSK6-mediated corin activation is essential for normal blood pressure

    PubMed Central

    Chen, Shenghan; Cao, Pengxiu; Dong, Ningzheng; Peng, Jianhao; Zhang, Chunyi; Wang, Hao; Zhou, Tiantian; Yang, Junhua; Zhang, Yue; Martelli, Elizabeth E; Prasad, Sathyamangla V Naga; Miller, Rachel E; Malfait, Anne-Marie; Zhou, Yiqing; Wu, Qingyu

    2016-01-01

    Hypertension is the most common cardiovascular disease, afflicting >30% of adults1. The cause of hypertension in most individuals remains unknown2,3, suggesting that additional contributing factors have yet to be discovered. Corin is a serine protease that activates the natriuretic peptides, thereby regulating blood pressure4. It is synthesized as a zymogen that is activated by proteolytic cleavage. CORIN variants and mutations impairing corin activation have been identified in people with hypertension and pre-eclampsia5–9. To date, however, the identity of the protease that activates corin remains elusive. Here we show that proprotein convertase subtilisin/kexin-6 (PCSK6, also named PACE4; ref. 10) cleaves and activates corin. In cultured cells, we found that corin activation was inhibited by inhibitors of PCSK family proteases and by small interfering RN