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Sample records for lysozyme antimicrobial blend

  1. The Antimicrobial Peptide Lysozyme Is Induced after Multiple Trauma

    Directory of Open Access Journals (Sweden)

    Tim Klüter

    2014-01-01

    Full Text Available The antimicrobial peptide lysozyme is an important factor of innate immunity and exerts high potential of antibacterial activity. In the present study we evaluated the lysozyme expression in serum of multiple injured patients and subsequently analyzed their possible sources and signaling pathways. Expression of lysozyme was examined in blood samples of multiple trauma patients from the day of trauma until 14 days after trauma by ELISA. To investigate major sources of lysozyme, its expression and regulation in serum samples, different blood cells, and tissue samples were analysed by ELISA and real-time PCR. Neutrophils and hepatocytes were stimulated with cytokines and supernatant of Staphylococcus aureus. The present study demonstrates the induction and release of lysozyme in serum of multiple injured patients. The highest lysozyme expression of all tested cells and tissues was detected in neutrophils. Stimulation with trauma-related factors such as interleukin-6 and S. aureus induced lysozyme expression. Liver tissue samples of patients without trauma show little lysozyme expression compared to neutrophils. After stimulation with bacterial fragments, lysozyme expression of hepatocytes is upregulated significantly. Toll-like receptor 2, a classic receptor of Gram-positive bacterial protein, was detected as a possible target for lysozyme induction.

  2. Lysozyme Catalyzes the Formation of Antimicrobial Silver Nanoparticles (POSTPRINT)

    Science.gov (United States)

    2009-04-01

    aseptics and therapeutic use in the future. KEYWORDS: antimicrobial · lysozyme · silver · nanoparticle · biocompatibility · biomineralization A RT IC LE VOL...protein that will adsorb to ionic and hydro- phobic surfaces, including metal surfaces.2124 After synthesis in methanol, lysozyme-stabilized nanoparti- cle...the strong ionic interactions be- tween metal nanoparticles normally make it difficult to achieve high concentrations of monodispersed and stable

  3. Influence of some formulation and process parameters on the stability of lysozyme incorporated in corn flour- or corn starch-based extruded materials prepared by melt blending processing.

    Science.gov (United States)

    Jbilou, Fouzia; Galland, Sophie; Telliez, Camille; Akkari, Zied; Roux, Roselyne; Oulahal, Nadia; Dole, Patrice; Joly, Catherine; Degraeve, Pascal

    2014-12-01

    In order to obtain an antimicrobial biodegradable material, corn flour was extruded with 1% of lysozyme. Since the limited stability of natural preservatives such as lysozyme is a common bottleneck to the elaboration of active biomaterials by melt blending processes, the influence of formulation and of extrusion processing temperature on its residual enzymatic activity was investigated. To assess the contribution of process parameters such as temperature, shear stress and of related formulation parameters such as glycerol and moisture contents, the stability of lysozyme following its extrusion or its thermoforming with plasticized corn starch or thermal treatments in aqueous glycerol solutions was also studied. Increasing glycerol content from 25% to 30% significantly limited inactivation of lysozyme during extrusion, while increasing initial moisture content of the mixture from 14.5% to 28.5% had the opposite effect. These observations open the possibility to prepare active materials retaining more than 60±7% of initial lysozyme activity.

  4. Covalent immobilization of lysozyme on ethylene vinyl alcohol films for nonmigrating antimicrobial packaging applications.

    Science.gov (United States)

    Muriel-Galet, V; Talbert, J N; Hernandez-Munoz, P; Gavara, R; Goddard, J M

    2013-07-10

    The objective of this study was to develop a new antimicrobial film, in which lysozyme was covalently attached onto two different ethylene vinyl alcohol copolymers (EVOH 29 and EVOH 44). The EVOH surface was modified with UV irradiation treatment to generate carboxylic acid groups, and lysozyme was covalently attached to the functionalized polymer surface. Surface characterization of control and modified films was performed using attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR) and dye assay. The value of protein loading after attachment on the surface was 8.49 μg protein/cm(2) and 5.74 μg protein/cm(2) for EVOH 29 and EVOH 44, respectively, after 10 min UV irradiation and bioconjugation. The efficacy of the EVOH-lysozyme films was assessed using Micrococcus lysodeikticus. The antimicrobial activity of the films was tested against Listeria monocytogenes and was similar to an equivalent amount of free enzyme. The reduction was 1.08 log for EVOH 29-lysozyme, 0.95 log for EVOH 44-lysozyme, and 1.34 log for free lysozyme. This work confirmed the successful use of lysozyme immobilization on the EVOH surface for antimicrobial packaging.

  5. Antimicrobial activity of lysozyme with special relevance to milk

    African Journals Online (AJOL)

    STORAGESEVER

    2008-12-29

    Dec 29, 2008 ... Lysozyme is a hydrolytic enzyme which has been purified from cells, secretions and tissues of virtually ... breakdown of peptidoglycan polymers of bacterial cell ...... Small Rum. ..... myeloid leukemia: An analysis of 208 cases.

  6. Antimicrobial lysozyme-containing starch microgel to target and inhibit amylase-producing micro-organisms

    NARCIS (Netherlands)

    Li, Yuan; Kadam, S.; Abee, T.; Slaghek, T.M.; Timmermans, J.W.; Cohen Stuart, M.A.; Norde, W.; Kleijn, J.M.

    2012-01-01

    The aim of this study is to determine the release of lysozyme from oxidized starch microgels and subsequently test its antimicrobial activity. The gels are made of oxidized potato starch polymers, which are chemically cross-linked by sodium trimetaphosphate (STMP). The microgel is negatively charged

  7. Antimicrobial lysozyme-containing starch microgel to target and inhibit amylase-producing microorganisms

    NARCIS (Netherlands)

    Li, Yuan; Kadam, Sachin; Abee, Tjakko; Slaghek, Ted M.; Timmermans, Johan W.; Stuart, Martien A. Cohen; Norde, Willem; Kleijn, Mieke J.

    2012-01-01

    The aim of this study is to determine the release of lysozyme from oxidized starch microgels and subsequently test its antimicrobial activity. The gels are made of oxidized potato starch polymers, which are chemically cross-linked by sodium trimetaphosphate (STMP). The microgel is negatively charged

  8. Antimicrobial lysozyme-containing starch microgel to target and inhibit amylase-producing micro-organisms

    NARCIS (Netherlands)

    Li, Yuan; Kadam, S.; Abee, T.; Slaghek, T.M.; Timmermans, J.W.; Cohen Stuart, M.A.; Norde, W.; Kleijn, J.M.

    2012-01-01

    The aim of this study is to determine the release of lysozyme from oxidized starch microgels and subsequently test its antimicrobial activity. The gels are made of oxidized potato starch polymers, which are chemically cross-linked by sodium trimetaphosphate (STMP). The microgel is negatively charged

  9. Antimicrobial lysozyme-containing starch microgel to target and inhibit amylase-producing microorganisms

    NARCIS (Netherlands)

    Li, Y.; Kadam, S.; Abee, T.; Slaghek, T.M.; Timmermans, J.W.; Cohen Stuart, M.A.; Norde, W.; Kleijn, M.J.

    2012-01-01

    The aim of this study is to determine the release of lysozyme from oxidized starch microgels and subsequently test its antimicrobial activity. The gels are made of oxidized potato starch polymers, which are chemically cross-linked by sodium trimetaphosphate (STMP). The microgel is negatively charged

  10. Antimicrobial lysozyme-containing starch microgel to target and inhibit amylase-producing microorganisms

    NARCIS (Netherlands)

    Li, Yuan; Kadam, Sachin; Abee, Tjakko; Slaghek, Ted M.; Timmermans, Johan W.; Stuart, Martien A. Cohen; Norde, Willem; Kleijn, Mieke J.

    The aim of this study is to determine the release of lysozyme from oxidized starch microgels and subsequently test its antimicrobial activity. The gels are made of oxidized potato starch polymers, which are chemically cross-linked by sodium trimetaphosphate (STMP). The microgel is negatively charged

  11. Antimicrobial activity and synergism of lactoferrin and lysozyme against cariogenic microorganisms.

    Science.gov (United States)

    de Andrade, Flaviana Bombarda; de Oliveira, Jair Caetano; Yoshie, Marjorie Takei; Guimarães, Bruno Martini; Gonçalves, Rafael Braga; Schwarcz, Waleska Dias

    2014-01-01

    The present study evaluated the antimicrobial in vitro effects of the salivary proteins lactoferrin and lysozyme on microorganisms involved in the carious process, obtaining their minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC). Streptococcus mutans (ATCC 25175) and Lactobacillus casei (ATCC 7469) were submitted to broth macrodilution of lysozyme at 80 mg/mL and lactoferrin at 200 mg/mL. The tubes were read in a spectrophotometer after they had been incubated at 37 °C for 18 h, in a carbon dioxide chamber, in order to read the MIC. A new subculture was carried on agar plates to obtain the MBC. The agar diffusion method was also tested, using BHI agar with 100 µL of the standardized microbial inocula. Filter-paper disks soaked in 10 µL of the solutions lactoferrin (200 µg/mL) and lysozyme (80 µg/mL) were placed on the agar surface. Inhibition halos were not observed on the plates, showing the absence of the antimicrobial effects of these proteins in this method. The bactericidal and bacteriostatic effects of lysozyme on L. casei were 50.3 mg/mL and 43.1 mg/mL respectively. The bactericidal and bacteriostatic effects on S. mutans were 68.5 mg/mL and 58.7 mg/mL. Lactoferrin did not induce any inhibitory effects on any microorganism, even in the concentration of 200 mg/mL. There was not a synergic antimicrobial effect of proteins, when they were tested together, even in the concentration of 42.8 mg/mL of lysozyme and 114 mg/mL of lactoferrin (the highest values evaluated). S. mutans and L. casei were only inhibited by lysozyme, not affected by lactoferrin and by the synergic use of both proteins.

  12. Enhancement of nisin, lysozyme, and monolaurin antimicrobial activities by ethylenediaminetetraacetic acid and lactoferrin.

    Science.gov (United States)

    Branen, Jill K; Davidson, P Michael

    2004-01-01

    A microtiter plate assay was employed to systematically assess the interaction between ethylenediaminetetraacetic acid (EDTA) or lactoferrin and nisin, lysozyme, or monolaurin against strains of Listeria monocytogenes, Escherichia coli, Salmonella enteritidis, and Pseudomonas fluorescens. Low levels of EDTA acted synergistically with nisin and lysozyme against L. monocytogenes but EDTA and monolaurin interacted additively against this microorganism. EDTA synergistically enhanced the activity of nisin, monolaurin, and lysozyme in tryptic soy broth (TSB) against two enterohemorrhagic E. coli strains. In addition, various combinations of nisin, lysozyme, and monolaurin with EDTA were bactericidal to some gram-negative bacteria whereas none of the antimicrobials alone were bactericidal. Lactoferrin alone (2000 microg ml(-1)) did not inhibit any of the bacterial strains, but did enhance nisin activity against both L. monocytogenes strains. Lactoferrin in combination with monolaurin inhibited growth of E. coli O157:H7 but not E. coli O104:H21. While lactoferrin combined with nisin or monolaurin did not completely inhibit growth of the gram-negative bacteria, there was some growth inhibition. All combinations of EDTA or lactoferrin with antimicrobials were less effective in 2% fat UHT milk than in TSB. S. enteritidis and P. fluorescens strains were consistently more resistant to antimicrobial combinations. Resistance may be due to differences in the outer membrane and/or LPS structure.

  13. Properties of lysozyme/sodium alginate complexes for the development of antimicrobial films.

    Science.gov (United States)

    Amara, Chedia Ben; Eghbal, Noushin; Oulahal, Nadia; Degraeve, Pascal; Gharsallaoui, Adem

    2016-11-01

    Complexation study of lysozyme (0.714g/L) by sodium alginate at pH7 showed that aggregates formation was a two-phase process. The first phase (from 0 to 0.1g/L sodium alginate) corresponded to the combination of individual complexes to form aggregates which caused an increase of turbidity and average size and a rapid sedimentation. Charge neutralization estimated by ζ-potential measurements occurred at 0.1g/L sodium alginate concentration. The second phase (from 0.1 to 4g/L of sodium alginate) was characterized by the formation of aggregates having a less dense structure with higher average size despite the drop in turbidity and the high dispersion in the medium. Lysozyme enzymatic activity decreased upon complexation with sodium alginate but was fully recovered after calcium chloride addition. In order to check whether lysozyme reversible inactivation was only due to substrate diffusion limitation or to conformational changes upon complexation, fluorescence and UV-Vis absorption measurements were performed. Moreover, lysozyme/sodium alginate complexes were used to manufacture an edible antimicrobial film to target lysozyme sensitive microorganisms. Copyright © 2016 Elsevier Ltd. All rights reserved.

  14. Interactions between high pressure homogenization and antimicrobial activity of lysozyme and lactoperoxidase.

    Science.gov (United States)

    Vannini, L; Lanciotti, R; Baldi, D; Guerzoni, M E

    2004-07-15

    It was the objective of this work to evaluate the effect of high pressure homogenization on the activity of antimicrobial enzymes such as lysozyme and lactoperoxidase against a selected group of Gram positive and Gram negative species inoculated in skim milk. Lactobacillus helveticus, Lactobacillus plantarum and Listeria monocytogenes were the most pressure resistant species while Bacillus subtilis, Pseudomonas putida, Salmonella typhimurium, Staphylococcus aureus, Proteus vulgaris and Salmonella enteritidis were found to be very sensitive to the hyperbaric treatment. The enzyme addition enhanced the instantaneous pressure efficacy on almost all the considered species as indicated by their instantaneous viability loss following the treatment. Moreover, the combination of the enzyme and high pressure homogenization significantly affected the recovery and growth dynamics of several of the considered species. Although L. monocytogenes was slightly sensitive to pressure, the combination of the two stress factors induced a significant viability loss within 3 h and an extension of lag phases in skim milk during incubation at 37 degrees C. The hypothesis formulated in this work is that the interaction of high pressure homogenization and lysozyme or lactoperoxidase is associated to conformational modifications of the two proteins with a consequent enhancement of their activity. This hypothesis is supported by the experimental results also regarding the increased antimicrobial activity against L. plantarum of the previously pressurised lysozyme with respect to that of the native enzyme.

  15. Antimicrobial chitosan-lysozyme (CL) films and coatings for enhancing microbial safety of mozzarella cheese.

    Science.gov (United States)

    Duan, J; Park, S-I; Daeschel, M A; Zhao, Y

    2007-11-01

    This study investigated the antimicrobial activities of chitosan-lysozyme (CL) composite films and coatings against tested microorganisms inoculated onto the surface of Mozzarella cheese. CL film-forming solutions (FFS) with a pH of 4.4 to 4.5 were prepared by incorporating 0% or 60% lysozyme (per dry weight of chitosan) into chitosan FFS with or without a pH adjustment to 5.2. Sliced cheese was subjected to 3 CL package applications: film, lamination on a multilayer coextruded film, and coating. Cheese was inoculated with Listeria monocytogenes, Escherichia coli, or Pseudomonas fluorescens at 10(4) CFU/g, or with mold and yeast at 10(2) CFU/g. Inoculated cheese was individually vacuum packaged and stored at 10 degrees C for sampling at 1, 7, and 14 d for bacteria, and at 10, 20, and 30 d for fungi. Inoculated bacteria survived but failed to multiply in untreated cheese during storage. Treated cheese received 0.43- to 1.25-, 0.40- to 1.40-, and 0.32- to 1.35-log reductions in E. coli, P. fluorescens, and L. monocytogenes, respectively. Incorporation of 60% lysozyme in chitosan FFS showed greater antimicrobial effect than chitosan alone on P. fluorescens and L. monocytogenes. The pH adjustment only affected the antimicrobial activity on L. monocytogenes, with lower pH (unadjusted) showing greater antimicrobial effect than pH 5.2. Mold and yeast increased to 10(5) CFU/g in untreated cheese after 30 d storage. Growth of mold was completely inhibited in cheese packaged with CL films, while 0.24- to 1.90- and 0.06- to 0.50-log reductions in mold populations were observed in cheese packaged with CL-laminated films and coatings, respectively. All CL packaging applications resulted in 0.01- to 0.64-log reduction in yeast populations.

  16. Assessment of antimicrobial activity of c-type lysozyme from Indian shrimp Fenneropenaeus indicus

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    Viswanathan Karthik

    2014-10-01

    Full Text Available Objective: To assess the multitudinal antimicrobial effects of recombinant lysozyme from Fenneropenaeus indicus (rFi-Lyz in comparison with commercially available recombinant hen egg white lysozyme (rHEWL. Methods: Antimicrobial activity of the recombinant rFi-Lyz using several Gram positive, Gram negative bacteria and fungi in comparison with rHEWL has been evaluated. rFi-Lyz was expressed and purified using Ni2+ affinity chromatography. The effect of rFi-Lyz in the growth of yeast Candida krusei, plant molds Rhizoctonia solani and Fusarium solani was assessed by well diffusion assay in petri plates with potato dextrose agar. Results: rFi-Lyz exhibited high inhibitory activity on Gram positive bacteria such as Staphylococcus aureus and Bacillus subtilis. Among various Gram negative bacteria tested Klebsiella pneumoniae exhibited the highest inhibition followed by Pseudomonas aeruginosa and Shigella dysenteriae. rFi-Lyz also exhibited significant inhibition on two marine pathogens Aeromonas veronii and Vibrio alginolyticus. Among the various fungal strains tested, rFi-Lyz inhibited the growth of budding yeast Candida krusei significantly. Further the growth of two other plants fungus Rhizoctonia solani and Fusarium oxysporum were retarded by rFi-Lyz in the plate inhibition assay. Conclusions: rFi-Lyz exhibits a broad spectrum of antimicrobial activity like a natural antibiotic on various pathogenic bacteria and fungal strains.

  17. Assessment of antimicrobial activity of c-type lysozyme from Indian shrimp Fenneropenaeus indicus

    Institute of Scientific and Technical Information of China (English)

    Viswanathan Karthik; Thomas Ancy; Dharmaraj Ramkumar; Narayanasamy Mathivanan; Rangarajan Badri Narayanan

    2014-01-01

    Objective: To assess the multitudinal antimicrobial effects of recombinant lysozyme fromFenneropenaeus indicus (rFi-Lyz) in comparison with commercially available recombinant hen egg white lysozyme (rHEWL).Methods:Antimicrobial activity of the recombinant rFi-Lyz using several Gram positive, Gram negative bacteria and fungi in comparison with rHEWL has been evaluated. rFi-Lyz was expressed and purified using Ni2+ affinity chromatography. The effect of rFi-Lyz in the growth of yeast Candida krusei, plant molds Rhizoctonia solani and Fusarium solani was assessed by well diffusion assay in petri plates with potato dextrose agar.Results: rFi-Lyz exhibited high inhibitory activity on Gram positive bacteria such as Staphylococcus aureus and Bacillus subtilis. Among various Gram negative bacteria testedKlebsiella pneumoniae exhibited the highest inhibition followed by Pseudomonas aeruginosa and Shigella dysenteriae. rFi-Lyz also exhibited significant inhibition on two marine pathogens Aeromonas veronii and Vibrio alginolyticus. Among the various fungal strains tested, rFi-Lyz inhibited the growth of budding yeast Candida krusei significantly. Further the growth of two other plants fungus Rhizoctonia solani and Fusarium oxysporum were retarded by rFi-Lyz in the plate inhibition assay.Conclusions: rFi-Lyz exhibits a broad spectrum of antimicrobial activity like a natural antibiotic on various pathogenic bacteria and fungal strains.

  18. Analysis of two lysozyme genes and antimicrobial functions of their recombinant proteins in Asian seabass.

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    Gui Hong Fu

    Full Text Available Lysozymes are important proteins of the innate immune system for the defense against bacterial infection. We cloned and analyzed chicken-type (c-type and goose-type (g-type lysozymes from Asian seabass (Lates calcarifer. The deduced amino acid sequence of the c-type lysozyme contained 144 residues and possessed typical structure residues, conserved catalytic residues (Glu(50 and Asp(67 and a "GSTDYGIFQINS" motif. The deduced g-type lysozyme contained 187 residues and possessed a goose egg white lysozyme (GEWL domain containing three conserved catalytic residues (Glu(71, Asp(84, Asp(95 essential for catalytic activity. Real time quantitative PCR (qRT-PCR revealed that the two lysozyme genes were constitutively expressed in all the examined tissues. The c-type lysozyme was most abundant in liver, while the g-type lysozyme was predominantly expressed in intestine and weakly expressed in muscle. The c-type and g-type transcripts were up-regulated in the kidney, spleen and liver in response to a challenge with Vibrio harveyi. The up-regulation of the c-type lysozyme was much stronger than that of the g-type lysozyme in kidney and spleen. The recombinant proteins of the c-type and g-type lysozymes showed lytic activities against the bacterial pathogens Vibrio harveyi and Photobacterium damselae in a dosage-dependent manner. We identified single nucleotide polymorphisms (SNPs in the two lysozyme genes. There were significant associations of these polymorphisms with resistance to the big belly disease. These results suggest that the c- and g-type genes play an important role in resistance to bacterial pathogens in fish. The SNP markers in the two genes associated with the resistance to bacterial pathogens may facilitate the selection of Asian seabass resistant to bacterial diseases.

  19. Enhancing the antimicrobial activity of Sus scrofa lysozyme by N-terminal fusion of a sextuple unique homologous peptide.

    Science.gov (United States)

    Zhu, Dewei; Cai, Guolin; Li, Xiaomin; Lu, Jian; Zhang, Liang

    2017-02-10

    Sus scrofa lysozyme (SSL), an important component of the pig immune system, is a potential candidate to replace antibiotics in feed. However, there is little antimicrobial activity of natural SSL against gram-negative bacteria, which limits its application. In this study, a unique peptide (A-W-V-A-W-K) with antimicrobial activity against gram-negative bacteria was discovered and purified from trypsin hydrolysate of natural SSL. This unique peptide was fused to natural SSL and the recombinant fused SSL exhibited improved activity against gram-negative bacteria. The N-terminal fusion likely increased the membrane penetrability and induced programmed bacterial cell death. The recombinant fused SSL also showed higher activity against some gram-positive bacteria with O-acetylation. By N-terminal fusion of the sextuple peptide, the anti-microbial activity, either to gram-positive or negative bacteria, of the recombinant SSL was higher than the fusion of only one copy of the peptide. This study provides a general, feasible, and highly useful strategy to enhance the antimicrobial activity of lysozyme.

  20. Expression, Characterization and Antimicrobial Ability of a Variant T4 Lysozyme in Pichia pastoris

    Institute of Scientific and Technical Information of China (English)

    Ning SUN; Sanfeng CHEN; Xiangming XIE; Yueju WANG; Gangqiang LI; Nan WANG; Dehu LIU

    2014-01-01

    T4 lysozyme was engineered with disulfide bonds and expressed in Pichia pastoris. The secreted proteins were purified and made into powder by lyophiliza-tion. Recombinant protein purity was more than 70% measured by HPLC. The lytic activity of variant T4-lysozyme was measured by the lysis of the cel wal of Xan-thomonas oryzae pv. oryzae, X. oryzae pv. oryzicola, Ralstonia solanacearum comb. nov, Clavibacter michiganensis subsp. michiganensis, X. campestris pv. mal-vacearum, Fusarium oxysporium sp. vasinfectum, Verticil ium dahliae kleb. Inhibition zone assay showed that variant T4 lysozyme significantly inhibited X. o. oryzicola and X. c. malvacearum. The antifungal activities of this protein against F. o. vasin-fectum and V. d. kleb were also analyzed.

  1. Study on Antimicrobial and Antiviral Activities of Lysozyme From Marine Strain S-12-86 In Vitro

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    In this study, the in vitro antimicrobial and antiviral activities of the lysozyme from marine strain S-12-86 (LS) were investigated. The antimicrobial activity of LS was tested by minimum inhibition concentration (MIC) and minimum bactericidal concentration (MBC) method. The inhibiting effects of LS on pseudo rabies virus (PRV) in swine kidney cells (PK-15 cells) were judged by cytopathogenic effect test (CPE). The results showed LS had a broad antimicrobial spectrum against several standard strains including gram-positive bacteria, gram-negative bacteria, fungi, etc. The MIC of LS was 0.25-4.00 mg mL-1 and its MBC was 0.25-8.00 mg mL-1, respectively. Observation under the transmission electron microscope revealed that the cell wall of Candida albicans was distorted seriously, and the cytoplasm with many cavities was asymmetrical after being hydrolyzed by LS. The median cytotoxicity concentration (TC50) of LS was 100.0 μg mL-1, the median effective concentration (EC50) was 0.46 μg mL-1, and the selectivity index (TI = TC50/EC50) was 217. LS could inhibit PRV in PK-15 cells when it was added to cell culture medium at 0, 2, 4, 6, and 8 h after PK-15 cells had been infected by PRV. From the results, we concluded that LS had broad antimicrobial spectrum and good inhibiting effects on PRV.

  2. The Natural Antimicrobial Enzyme Lysozyme is Up-Regulated in Gastrointestinal Inflammatory Conditions

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    Carlos A. Rubio

    2014-01-01

    Full Text Available The cells that line the mucosa of the human gastrointestinal tract (GI, that is, oral cavity, oesophagus, stomach, small intestine, large intestine, and rectum are constantly challenged by adverse micro-environmental factors, such as different pH, enzymes, and bacterial flora. With exception of the oral cavity, these microenvironments also contain remnant cocktails of secreted enzymes and bacteria from upper organs along the tract. The density of the GI bacteria varies, from 103/mL near the gastric outlet, to 1010/mL at the ileocecal valve, to 1011 to 1012/mL in the colon. The total microbial population (ca. 1014 exceeds the total number of cells in the tract. It is, therefore, remarkable that despite the prima facie inauspicious mixture of harmful secretions and bacteria, the normal GI mucosa retains a healthy state of cell renewal. To counteract the hostile microenvironment, the GI epithelia react by speeding cell exfoliation (the GI mucosa has a turnover time of two to three days, by increasing peristalsis, by eliminating bacteria through secretion of plasma cell-immunoglobulins and by increasing production of natural antibacterial compounds, such as defensin-5 and lysozyme. Only recently, lysozyme was found up-regulated in Barrett’s oesophagitis, chronic gastritis, gluten-induced atrophic duodenitis (coeliac disease, collagenous colitis, lymphocytic colitis, and Crohn’s colitis. This up-regulation is a response directed to the special types of bacteria recently detected in these diseases. The aim of lysozyme up-regulation is to protect individual mucosal segments to chronic inflammation. The molecular mechanisms connected to the crosstalk between the intraluminal bacterial flora and the production of lysozyme released by the GI mucosae, are discussed. Bacterial resistance continues to exhaust our supply of commercial antibiotics. The potential use of lysozyme to treat infectious diseases is receiving much attention.

  3. Mechanical, physico-chemical, and antimicrobial properties of gelatin-based film incorporated with catechin-lysozyme

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    Rawdkuen Saroat

    2012-11-01

    Full Text Available Abstract Background Microbial activity is a primary cause of deterioration in many foods and is often responsible for reduced quality and safety. Food-borne illnesses associated with E. coli O157:H7, S. aureus, S. enteritidis and L. monocytogenes are a major public health concern throughout the world. A number of methods have been employed to control or prevent the growth of these microorganisms in food. Antimicrobial packaging is one of the most promising active packaging systems for effectively retarding the growth of food spoilage and pathogenic microorganisms. The aim of this study was to determine the mechanical, physico-chemical properties and inhibitory effects of the fish gelatin films against selected food spoilage microorganisms when incorporated with catechin-lysozyme. Results The effect of the catechin-lysozyme combination addition (CLC: 0, 0.125, 0.25, and 0.5%, w/v on fish gelatin film properties was monitored. At the level of 0.5% addition, the CLC showed the greatest elongation at break (EAB at 143.17% with 0.039 mm thickness, and the lowest water vapor permeability (WVP at 6.5 x 10−8 g·mm·h-1·cm-2·Pa-1, whereas the control showed high tensile strength (TS and the highest WVP. Regarding color attributes, the gelatin film without CLC addition gave the highest lightness (L* 91.95 but lowest in redness (a*-1.29 and yellowness (b* 2.25 values. The light transmission of the film did not significantly decrease and nor did film transparency (p>0.05 with increased CLC. Incorporating CLC could not affect the film microstructure. The solubility of the gelatin based film incorporated with CLC was not affected, especially at a high level of addition (p>0.05. Inhibitory activity of the fish gelatin film against E.coli, S.aureus, L. innocua and S. cerevisiae was concentration dependent. Conclusions These findings suggested that CLC incorporation can improve mechanical, physico-chemical, and antimicrobial properties of the resulting films

  4. Carboxymethylcellulose acetate butyrate/poly(4-vinyl-N-pentyl pyridinium bromide blends as antimicrobial coatings

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    L. S. Blachechen

    2015-09-01

    Full Text Available Blends of carboxymethyl cellulose acetate butyrate (CMCAB, a cellulose derivative, and poly(4-vinyl-N-pentyl pyridinium bromide (QPVP-C5, an antimicrobial polymer, were prepared by casting method and characterized by means of Fourier transform infrared vibrational spectroscopy (FTIR, scanning electron microscopy (SEM, thermogravimetric analysis (TGA, differential scanning calorimetry (DSC and contact angle measurements. Miscibility between CMCAB and QPVP-C5 was evidenced by DSC measurements of blends, which showed a single thermal event of Tg, and SEM images, which revealed homogenous morphology, regardless the blend composition. Moreover, thermal stability of QPVP-C5 was substantially enhanced, when it was mixed with CMCAB. Upon increasing the QPVP-C5 content in the blend the wettability and antimicrobial activity against Gram-positive bacteria Micrococcus luteus increased, indicating the surface enrichment by pyridinium groups. In fact, blends with 70 wt% QPVP-C5 reduced 5 log and 4 log the colony-forming units of Micrococcus luteus and Escherichia coli, respectively.

  5. Antimicrobial Constituents and Effects of Blended Eucalyptus, Rosemary, Patchouli, Pine, and Cajuput Essential Oils.

    Science.gov (United States)

    Tadtong, Sarin; Puengseangdee, Chompunut; Prasertthanawut, Suwapit; Hongratanaworakit, Tapanee

    2016-02-01

    The synergistic antimicrobial activities of blended essential oil preparations composed of eucalyptus, rosemary, patchouli, pine and cajuput oils were evaluated against various pathogenic microorganisms. They exhibited antimicrobial activity in the agar disc diffusion assay against the Gram-positive bacteria, Staphylococcus aureus and S. epidenidis, the Gram-negative bacteria, Escherichia coli and Pseudomonas aeruginosa, and the yeast, Candida albicans. The minimum inhibitory concentration (MIC) of these preparations was evaluated by the broth microdilution method. We found that the best synergistic antibacterial preparation (the sum of fractional inhibitory concentrations, Σfic oils (volume ratio 4:4:2) without patchouli, pine or cajuput oils added, while most preparations showed an antagonistic anticandidal effect (Σfic > 1). The blended essential oil preparations were characterized for their components by GC/MS, and contained 1,8-cineole as a major component. However, the preparation containing the highest amount of 1,8-cineole did not exhibit the best synergistic effect, which was shown by the preparation comprising the highest amount of α-pinene. Hence, we concluded that the differential antibacterial effect of either blended oil preparations or single/pure essential oils was influenced by the amount of α-pinene and the number of active components in either the blended preparations or single/pure essential oils.

  6. Release of lysozyme from electrospun PVA/lysozyme-gelatin scaffolds

    Institute of Scientific and Technical Information of China (English)

    Dong-zhi YANG; Yu-hua LONG; Jun NIE

    2008-01-01

    This article describes an electrospinning process in fabricating ultra fine fibers with core-shell structure. A biodegradable polymer, poly(vinyl alcohol) (PVA), was used as the shell; lysozyme was a kind of antioxidant; and gelatin were used as the core. Morphology and microstruc-ture of the ultra fine fibers were characterized by scanning electron microscope (SEM), transmission electron micro-scopy (TEM) and X-ray photoelectron spectroscopy (XPS) analysis. As a comparison, composite nanofiber PVA/lysozyme-gelatin blend was prepared by a normal electrospinning process. In vitro drug release behaviors of the nanofibrous membranes were determined in phosphate-buffered saline (PBS) solution. It was found that core-shell nanofibers PVA/lysozyme-gelatin obviously exhibit higher initial release rates compared to that of PVA/lysozyme-gelatin blend nanofibers. The current method may find wide application in controlled release of bioactive proteins and tissue engineering.

  7. The use of chitosan, lysozyme, and the nano-silver as antimicrobial ingredients of edible protective hydrosols applied into the surface of meat.

    Science.gov (United States)

    Zimoch-Korzycka, Anna; Jarmoluk, Andrzej

    2015-09-01

    The aim of this study was to design and produce biologically active edible hydrosols, which, when applied to the surface of food products, will protect them from oxidative changes, spoilage and growth of microorganisms. Verification of testing hypothesis and the degree of aim realization were performed by assessing a DPPH radical scavenging activity and microbial reduction of experimental hydrosols on the basis of hydroxypropylmethylcellulose (HPMC), chitosan (CH), lysozyme (L) and nanocolloidal silver (NAg). Antimicrobial activity of different concentrations of CH, L and NAg hydrosols against Gram (+) bacteria: Bacilllus cereus and Micrococcus flavus and Gram (-) bacteria: Escherichia coli and Pseudomonas fluorescens, which exist more often in food, were analyzed using serial dilution test. Total number of microorganisms was determined on meat sample covered by tested sols. Hydrosols containing chitosan and other bioactive substances caused death of each tested microorganism. Lack of chitosan in hydrosols is reflected in a slight inhibition of M. flavus, E. coli and P. fluorescens. Simultaneous influence of CH, L and NAg addition and storage time on total number of bacteria in meat samples with hydrosols was showed. The addition of lysozyme to sols composition significantly increases antioxidant activity.

  8. EFSA Panel on Dietetic Products, Nutrition and Allergies (NDA); Scientific Opinion related to a notification from the Oenological Products and Practices International Association (OENOPPIA) on lysozyme from hen‟s egg to be used in the manufacture of wine as an anti-microbial stabilizer/additive

    DEFF Research Database (Denmark)

    Tetens, Inge

    in the manufacture of wine as an anti-microbial stabilizer/additive pursuant to Article 6, paragraph 11 of Directive 2000/13/EC – for permanent exemption from labelling. Allergic sensitisation against lysozyme is common among egg allergic individuals. In winemaking, lysozyme is used for the control of lactic acid...

  9. Antimicrobial wool, polyester and a wool/polyester blend created by silver particles embedded in a silica matrix.

    Science.gov (United States)

    Klemenčič, Danijela; Tomšič, Brigita; Kovač, Franci; Žerjav, Metka; Simončič, Andrej; Simončič, Barbara

    2013-11-01

    A two-step antimicrobial finishing procedure was applied to wool (WO) and polyester (PES) fabrics and a WO/PES fabric blend, in which the pad-dry-cure method was performed to create a functional silica matrix through the application of an inorganic-organic hybrid sol-gel precursor (RB) followed by the in situ synthesis of AgCl particles on the RB-treated fibres using 0.10 and 0.50mM AgNO3 and NaCl. The bulk concentration of Ag on the cotton fibres was determined by inductively coupled plasma mass spectroscopy. The antimicrobial activity was determined for the bacteria Escherichia coli and Staphylococcus aureus, and the fungus Aspergillus niger. The results showed that the highest concentration of the adsorbed Ag compound particles was on the WO samples followed by the WO/PES and PES samples. The antimicrobial activity of the finished fabric samples strongly depended not only on the amount of adsorbed Ag but also on the properties of the fabric samples. Whereas Ag biocidal activity was generated for the finished PES samples at Ag particle concentrations of less than 10mg/kg, the 34-times higher Ag particle concentration on the WO samples was insufficient to impart satisfactory antimicrobial activity because Ag chemically binds to the thiol groups on wool. The presence of wool fibres in WO/PES samples decreased the antimicrobial protection of the fabric blend compared with that of the PES fabric. A lethal concentration of adsorbed Ag compound particles for bacteria and fungi was produced only through the treatment of the WO and WO/PES samples with 0.5mM AgNO3.

  10. Characterization of antimicrobial properties on the growth of S. aureus of novel renewable blends of gliadins and chitosan of interest in food packaging and coating applications.

    Science.gov (United States)

    Fernandez-Saiz, P; Lagaron, J M; Hernandez-Muñoz, P; Ocio, M J

    2008-05-10

    The biocide properties of chitosan-based materials have been known for many years. However, typical antimicrobial formulations of chitosan, mostly chitosonium salts, are known to be very water sensitive materials which may impair their use in many application fields such as food packaging or food coating applications. This first work reports on the development and characterization of the antimicrobial properties of novel fully renewable blends of chitosan with more water-resistant gliadin proteins isolated from wheat gluten. Chitosan release to the nutrient broth from a wide range of blends was studied making use of the ninhydrin method. The results indicated that both pure chitosan and its blends with gliadins presented significant antimicrobial activity, which increased with increasing the amount of chitosan in the composite formulation as expected. The gliadins-chitosan blends showed good transparency and film-forming properties and better water resistance than pure chitosan. The release tests revealed that dissolution of the biocide glucosamine groups, i.e. the chitosan water soluble fractions, also increased with the amount of chitosan present in the formulation. The release of these groups was for the first time directly correlated with the antimicrobial properties exhibited by the blends. Thus, incorporation of chitosan into an insoluble biopolymer matrix was revealed as a very feasible strategy to generate novel chitosan-based antimicrobial materials with potential advantages, for instance active food packaging applications.

  11. Preparation of Cu{sub 2}O nanowire-blended polysulfone ultrafiltration membrane with improved stability and antimicrobial activity

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Zehai; Ye, Shuaiju; Fan, Zheng; Ren, Fanghua; Gao, Congjie [Zhejiang University of Technology, Institute of Oceanic and Environmental Chemical Engineering, College of Chemical Engineering and Material Science and College of Ocean, and State Key Lab Breeding Base of Green Chemical Synthesis Technology and Zhejiang Collaborative Innovation Center of Membrane Separation and Water Treatment (China); Li, Qingbiao; Li, Guoqing [Quanzhou Normal University, College of Chemistry and Life Science (China); Zhang, Guoliang, E-mail: membrane86571@163.com, E-mail: guoliangz@zjut.edu.cn [Zhejiang University of Technology, Institute of Oceanic and Environmental Chemical Engineering, College of Chemical Engineering and Material Science and College of Ocean, and State Key Lab Breeding Base of Green Chemical Synthesis Technology and Zhejiang Collaborative Innovation Center of Membrane Separation and Water Treatment (China)

    2015-10-15

    Polysulfone (PSF) membranes have been widely applied in water and wastewater treatment, food-processing and biomedical fields. In this study, we report the preparation of modified PSF membranes by blending PSF with Cu{sub 2}O nanowires (NWs) to improve their stability and antifouling activity. Synthesis of novel Cu{sub 2}O NWs/PSF-blended ultrafiltration membrane was achieved via phase inversion method by dispersing one-dimensional Cu{sub 2}O nanowires in PSF casting solutions. Various techniques such as XRD, SEM, TEM, and EDS were applied to characterize and investigate the properties of nanowires and membranes. The introduced Cu{sub 2}O nanowires can firmly be restricted into micropores of PSF membranes, and therefore, they can effectively prevent the serious leaking problem of inorganic substances in separation process. The blended PSF membranes also provided enhanced antimicrobial activity and superior permeation property compared to pure PSF membrane. The overall work can not only provide a new way for preparation of novel blended membranes with multidimensional nanomaterials, but can also be beneficial to solve the annoying problem of biofouling.

  12. Recent advances for the production and recovery methods of lysozyme.

    Science.gov (United States)

    Ercan, Duygu; Demirci, Ali

    2016-12-01

    Lysozyme is an antimicrobial peptide with a high enzymatic activity and positive charges. Therefore, it has applications in food and pharmaceutical industries as an antimicrobial agent. Lysozyme is ubiquitous in both animal and plant kingdoms. Currently, egg-white lysozyme is the most commercially available form of lysozyme. The main concerns of egg-white lysozyme are high recovery cost, low activity and most importantly the immunological problems to some people. Therefore, human lysozyme production has gained importance in recent years. Scientists have developed transgenic plants, animals and microorganisms that can produce human lysozyme. Out of these, microbial production has advantages for commercial productions, because high production levels are achievable in a relatively short time. It has been reported that fermentation parameters, such as pH, temperature, aeration, are key factors to increase the effectiveness of the human lysozyme production. Moreover, purification of the lysozyme from the fermentation broth needs to be optimized for the economical production. In conclusion, this review paper covers the mechanism of lysozyme, its sources, production methods and recovery of lysozyme.

  13. Antimicrobial Activity and the Chemical Composition of the Volatile Oil Blend from Allium sativum (Garlic Clove and Citrus reticulata (Tangerine Fruit

    Directory of Open Access Journals (Sweden)

    OO Johnson

    2013-10-01

    Full Text Available The synergistic effect in the antimicrobial activity of the volatile oil blend from Garlic clove (Allium sativum and tangerine fruits (Citrus reticulata were investigated and compared to antimicrobial activity when the individual volatile oils were used alone. The volatile oils were extracted by steam distillation using Clevenger hydrodistillator apparatus and each oil was tested for antimicrobial activity, while equal volume of these oils were blended and tested for antimicrobial activity. The microorganisms used include, Staphylococcus aureus isolate, Escherichia coli isolate, Pseudomonas aeruginosa, Salmonella typhi, Candida albicans isolate, Staphylococcus aureus ATCC 25923, Escherichia coli ATCC 25922 and Candida albicans ATCC 90028. The Minimum Inhibitory Concentrations (MICs ranged from 9.31×10-13 – 7.88 mg/ml for garlic oil, 0.16 – 2.66 mg/ml for tangerine oil and 5.95×10-31 – 1.24 mg/ml for the essential oil blend. Minimum Inhibitory Concentration indicated that the Garlic oil and Tangerine oil blend was better at inhibiting the tested microorganisms than the individual oils except for Escherichia coli ATCC 25922 and Staphylococcus aureus ATCC 25923. The Gas Chromatography-Mass Spectrometry revealed Trisulphide, di-2-propenyl (30.32% as the major component in the garlic oil extract and 3-Cyclohexene-1-methanol, alpha 4-trimethyl (33.38% in the tangerine oil. While the equal volume of the oil blend also revealed Trisulphide, di-2-propenyl (15.92% and 3-Cyclohexene-1-methanol, alpha.4-trimethyl (12.02% as the major constituents though in lower concentrations. Hence, the more potent antimicrobial properties demonstrated by the oil blend can be exploited further with a view to generate new effective antimicrobial compounds.

  14. IMMOBILIZATION OF LYSOZYME IN POLYVINYL ALCOHOL CRYOGEL

    Directory of Open Access Journals (Sweden)

    S. S. Dekina

    2014-06-01

    Full Text Available The lysozyme immobilization in cryogel of polyvinyl alcohol and physico-chemical properties of obtained preparation was investigated. Hydrolytic activity of lysozyme was determined by bacteriolytic method, using Micrococcus lysodeikticus cells acetone powder as substrate. Protein content was determined by the Lowry–Hartree method. Immobilization of lysozyme was conducted by entrapment in polyvinyl alcohol gel with subsequent cycles of freezing-thawing. Antimicrobial activity was studied by standard disk-diffusional method. The hydrogel filmic coatings with antimicrobial action, insoluble at physiological conditions, with quantitative retaining of protein and hydrolytic activity of lysozyme were obtained. The product is characterized by the widened pH-profile of activity at acidic pH values, stability in acidic medium (pH 5.5 and at storage. Its antimicrobial action against Staphylococcus aureus ATCC 25923 F-49, Pseudomonas aeruginosa 415, Escherichia coli 055 K 59912/4 and Candida albicans ATCC 885-653 was noted. The proposed method of lysozyme immobilization allows to obtain stable, highly effective product with antimicrobial activity, prospective for usage in biomedical investigations.

  15. Preparation and Application of Starch/Polyvinyl Alcohol/Citric Acid Ternary Blend Antimicrobial Functional Food Packaging Films

    Directory of Open Access Journals (Sweden)

    Zhijun Wu

    2017-03-01

    Full Text Available Ternary blend films were prepared with different ratios of starch/polyvinyl alcohol (PVA/citric acid. The films were characterized by field emission scanning electron microscopy (FE-SEM, thermogravimetric analysis, as well as Fourier transform infrared (FTIR analysis. The influence of different ratios of starch/polyvinyl alcohol (PVA/citric acid and different drying times on the performance properties, transparency, tensile strength (TS, water vapor permeability (WVP, water solubility (WS, color difference (ΔE, and antimicrobial activity of the ternary blends films were investigated. The starch/polyvinyl alcohol/citric acid (S/P/C1:1:0, S/P/C3:1:0.08, and S/P/C3:3:0.08 films were all highly transparent. The S/P/C3:3:0.08 had a 54.31 times water-holding capacity of its own weight and its mechanical tensile strength was 46.45 MPa. In addition, its surface had good uniformity and compactness. The S/P/C3:1:0.08 and S/P/C3:3:0.08 showed strong antimicrobial activity to Listeria monocytogenes and Escherichia coli, which were the food-borne pathogenic bacteria used. The freshness test results of fresh figs showed that all of the blends prevented the formation of condensed water on the surface of the film, and the S/P/C3:1:0.08 and S/P/C3:3:0.08 prevented the deterioration of figs during storage. The films can be used as an active food packaging system due to their strong antibacterial effect.

  16. Enhanced antibacterial activity of lysozyme immobilized on chitin nanowhiskers.

    Science.gov (United States)

    Jiang, Suisui; Qin, Yang; Yang, Jie; Li, Man; Xiong, Liu; Sun, Qingjie

    2017-04-15

    In this paper, the contribution of chitin nanowhiskers (CHNW) to the enzymatic activity and antimicrobial activity of lysozyme adsorbed on CHNW was investigated. An activity assay showed that the lysozyme-CHNW system exhibited significant promotion potency on lysozyme activity, which was approximately 1.5-fold greater than that of free lysozyme. The molecular promotion mechanism of lysozyme immobilized by adsorption onto CHNW was investigated by ultraviolet-visible spectrophotometry, fluorescence spectroscopy, and circular dichroism spectroscopy. The results indicated that changes in the secondary structure of lysozyme adsorption onto CHNW resulted in superior enzymatic activity. Furthermore, the antimicrobial assays indicated that the antimicrobial activity of the lysozyme-CHNW system was greater than that of free lysozyme, whereas its antimicrobial effect on a gram-negative bacterium was better than that on gram-positive bacteria. This research provides a facile and promising approach for increasing the application of chitin-derived and enhancing the antibacterial efficiency on preservation. Copyright © 2016 Elsevier Ltd. All rights reserved.

  17. Physical and Antimicrobial Properties of Starch-PVA Blend Films as Affected by the Incorporation of Natural Antimicrobial Agents

    Directory of Open Access Journals (Sweden)

    Amalia Cano

    2015-12-01

    Full Text Available In this work, active films based on starch and PVA (S:PVA ratio of 2:1 were developed by incorporating neem (NO and oregano essential oils (OEO. First, a screening of the antifungal effectiveness of different natural extracts (echinacea, horsetail extract, liquid smoke and neem seed oil against two fungus (P. expansum and A. niger was carried out. The effect of NO and OEO incorporation on the films’ physical and antimicrobial properties was analyzed. Only composite films containing OEO exhibited antibacterial and antifungal activity. Antibacterial activity occurred at low OEO concentration (6.7%, while antifungal effect required higher doses of OEO in the films. Incorporation of oils did not notably affect the water sorption capacity and water vapor barrier properties of S-PVA films, but reduced their transparency and gloss, especially at the highest concentrations. The mechanical response of the S-PVA films was also negatively affected by oil incorporation but this was only relevant at the highest oil ratio (22%. S-PVA films with 6.7% of OEO exhibited the best physical properties, without significant differences with respect to the S-PVA matrix, while exhibiting antibacterial activity. Thus, the use of OEO as a natural antimicrobial incorporated into starch-PVA films represents a good and novel alternative in food packaging applications.

  18. Physical and Antimicrobial Properties of Starch-PVA Blend Films as Affected by the Incorporation of Natural Antimicrobial Agents

    Science.gov (United States)

    Cano, Amalia; Cháfer, Maite; Chiralt, Amparo; González-Martínez, Chelo

    2015-01-01

    In this work, active films based on starch and PVA (S:PVA ratio of 2:1) were developed by incorporating neem (NO) and oregano essential oils (OEO). First, a screening of the antifungal effectiveness of different natural extracts (echinacea, horsetail extract, liquid smoke and neem seed oil) against two fungus (P. expansum and A. niger) was carried out. The effect of NO and OEO incorporation on the films’ physical and antimicrobial properties was analyzed. Only composite films containing OEO exhibited antibacterial and antifungal activity. Antibacterial activity occurred at low OEO concentration (6.7%), while antifungal effect required higher doses of OEO in the films. Incorporation of oils did not notably affect the water sorption capacity and water vapor barrier properties of S-PVA films, but reduced their transparency and gloss, especially at the highest concentrations. The mechanical response of the S-PVA films was also negatively affected by oil incorporation but this was only relevant at the highest oil ratio (22%). S-PVA films with 6.7% of OEO exhibited the best physical properties, without significant differences with respect to the S-PVA matrix, while exhibiting antibacterial activity. Thus, the use of OEO as a natural antimicrobial incorporated into starch-PVA films represents a good and novel alternative in food packaging applications.

  19. Resistance screening essay of wine lactic acid bacteria on lysozyme: efficacy of lysozyme in unclarified grape musts.

    Science.gov (United States)

    Delfini, Claudio; Cersosimo, Manuela; Del Prete, Vincenzo; Strano, Morela; Gaetano, Giuseppe; Pagliara, Adolfo; Ambrò, Stefano

    2004-04-01

    In wine making, the bacteriolytic activity of lysozyme has primarily been used to control the malolactic fermentation in wines. The use of lysozyme in musts before settling and the beginning of the alcoholic fermentation to inhibit the growth of lactic acid bacteria could be very beneficial. In a resistance test carried out in MT/b broth, lysozyme had greater antimicrobial activity toward Oenococcus oeni than Lactobacillus species. Several strains of wine bacteria belonging to Oenococcus proved sensitive to the bacteriolytic activity of lysozyme at low concentrations in both synthetic medium (MT/b) (50 mg/L), white must, or red must made with or without the skins (100 mg/L). Lactobacillus and Pediococcus strains survived at lysozyme concentrations of 200-500 and 500 mg/L, respectively, in MT/b and musts. Suspended solids in unclarified musts may strongly bind to lysozyme thereby causing its removal by filtration or centrifugation. One hour after lysozyme was added to musts, it was quantified by HPLC and found after centrifugation to be 40-50% and only 10% in musts made with or without the skins, respectively. Although appreciable amounts of lysozyme were bound to wine components, this did not appear to be a serious hindrance to lysozyme activity.

  20. Bioengineered lysozyme in combination therapies for Pseudomonas aeruginosa lung infections

    Science.gov (United States)

    Griswold, Karl E; Bement, Jenna L; Teneback, Charlotte C; Scanlon, Thomas C; Wargo, Matthew J; Leclair, Laurie W

    2014-01-01

    There is increasing urgency in the battle against drug-resistant bacterial pathogens, and this public health crisis has created a desperate need for novel antimicrobial agents. Recombinant human lysozyme represents one interesting candidate for treating pulmonary infections, but the wild type enzyme is subject to electrostatic mediated inhibition by anionic biopolymers that accumulate in the infected lung. We have redesigned lysozyme’s electrostatic potential field, creating a genetically engineered variant that is less susceptible to polyanion inhibition, yet retains potent bactericidal activity. A recent publication demonstrated that the engineered enzyme outperforms wild type lysozyme in a murine model of Pseudomonas aeruginosa lung infection. Here, we expand upon our initial studies and consider dual therapies that combine lysozymes with an antimicrobial peptide. Consistent with our earlier results, the charge modified lysozyme combination outperformed its wild type counterpart, yielding more than an order-of-magnitude reduction in bacterial burden following treatment with a single dose. PMID:24637705

  1. Study of lysozyme resistance in Rhodococcus equi.

    Science.gov (United States)

    Hébert, Laurent; Bidaud, Pauline; Goux, Didier; Benachour, Abdellah; Laugier, Claire; Petry, Sandrine

    2014-03-01

    Lysozyme is an important and widespread component of the innate immune response that constitutes the first line of defense against bacterial pathogens. The bactericidal effect of this enzyme relies on its capacity to hydrolyze the bacterial cell wall and also on a nonenzymatic mechanism involving its cationic antimicrobial peptide (CAMP) properties, which leads to membrane permeabilization. In this paper, we report our findings on the lysozyme resistance ability of Rhodococcus equi, a pulmonary pathogen of young foals and, more recently, of immunocompromised patients, whose pathogenic capacity is conferred by a large virulence plasmid. Our results show that (i) R. equi can be considered to be moderately resistant to lysozyme, (ii) the activity of lysozyme largely depends on its muramidase action rather than on its CAMP activity, and (iii) the virulence plasmid confers part of its lysozyme resistance capacity to R. equi. This study is the first one to demonstrate the influence of the virulence plasmid on the stress resistance capacity of R. equi and improves our understanding of the mechanisms enabling R. equi to resist the host defenses.

  2. High-level soluble expression of the functional peptide derived from the C-terminal domain of the sea cucumber lysozyme and analysis of its antimicrobial activity

    Directory of Open Access Journals (Sweden)

    Lina Cong

    2014-11-01

    Conclusion: These results indicate that the expressed rSjLys-C is a highly soluble product and has a strong antimicrobial activity. Therefore, gaining a large quantity of biologically active rSjLys-C will be used for further biochemical and structural studies and provide a potential use in aquaculture and medicine.

  3. The Invertebrate Lysozyme Effector ILYS-3 Is Systemically Activated in Response to Danger Signals and Confers Antimicrobial Protection in C. elegans

    Science.gov (United States)

    Gravato-Nobre, Maria João; Vaz, Filipa; Filipe, Sergio; Chalmers, Ronald; Hodgkin, Jonathan

    2016-01-01

    Little is known about the relative contributions and importance of antibacterial effectors in the nematode C. elegans, despite extensive work on the innate immune responses in this organism. We report an investigation of the expression, function and regulation of the six ilys (invertebrate-type lysozyme) genes of C. elegans. These genes exhibited a surprising variety of tissue-specific expression patterns and responses to starvation or bacterial infection. The most strongly expressed, ilys-3, was investigated in detail. ILYS-3 protein was expressed constitutively in the pharynx and coelomocytes, and dynamically in the intestine. Analysis of mutants showed that ILYS-3 was required for pharyngeal grinding (disruption of bacterial cells) during normal growth and consequently it contributes to longevity, as well as being protective against bacterial pathogens. Both starvation and challenge with Gram-positive pathogens resulted in ERK-MAPK-dependent up-regulation of ilys-3 in the intestine. The intestinal induction by pathogens, but not starvation, was found to be dependent on MPK-1 activity in the pharynx rather than in the intestine, demonstrating unexpected communication between these two tissues. The coelomocyte expression appeared to contribute little to normal growth or immunity. Recombinant ILYS-3 protein was found to exhibit appropriate lytic activity against Gram-positive cell wall material. PMID:27525822

  4. Effects of Chitosan, Lysozyme and Oregano Oil on Antimicrobial Activity of Soy Protein Isolate Film%壳聚糖、溶菌酶和牛至油对大豆分离蛋白膜抑菌效果的影响

    Institute of Scientific and Technical Information of China (English)

    杜会云; 赵寿经; 王新伟; 马中苏; 吴晓艳; 张艳平

    2011-01-01

    采用双倍稀释法研究壳聚糖、溶菌酶和牛至油对大肠杆菌和金黄色葡萄球菌的最小抑菌浓度.采用抑菌圈法研究添加天然抑菌剂壳聚糖、溶菌酶和牛至油的大豆分离蛋白膜对大肠杆菌、金黄色葡萄球菌、酿酒酵母和黑曲霉的抑菌效果.结果表明,添加壳聚糖、溶菌酶和牛至油的大豆分离蛋白膜对大肠杆菌、金黄色葡萄球菌、酿酒酵母和黑曲霉均有抑制作用.对大肠杆菌和金黄色葡萄球菌抑制效果为:牛至油>壳聚糖>溶菌酶.对酿酒酵母的抑制效果为:壳聚糖>牛至油>溶菌酶;对黑曲零的抑制效果为:牛至油>壳聚糖>溶菌酶.因此,添加壳聚糖、溶菌酶和牛至油的大豆分离蛋白膜具有较好的抑菌效果和应用前景.%Double dilution method was used to determine minimum inhibitory concentration of chitosan, lysozyme and oregano oil against Escherichia coli and Staphyloccocus aureus.Inhibition zone method was used to determine antimicrobial effect of soy protein isolate films enriched with chitosan, lysozyme and oregano oil against E.coli, S.aureus,Saccharomyces cerevisiae and Aspergillus niger.Results indicated that soy protein isolate films enriched with chitosan,lysozyme and oregano oil could inhibit the growth of E.coli, S.aureus, S.cerevisiae and A.niger.The inhibitory effect on E.coli and S.aureus: oregano oil > chitosan > lysozyme.The inhibitory effect on S.cerevisiae: chitosan > oregano oil > lysozyme; the inhibitory effect on A.niger: oregano oil > chitosan > lysozyme.This study showed the films enriched with chitosan, lysozyme and oregano oil have potential to be used as active biodegradable films with strong antimicrobial effects.

  5. Polyvinyl pyrrolidone/carrageenan blend hydrogels with nanosilver prepared by gamma radiation for use as an antimicrobial wound dressing.

    Science.gov (United States)

    Singh, Durgeshwer; Singh, Antaryami; Singh, Rita

    2015-01-01

    Hydrogels were prepared using polyvinyl pyrrolidone (PVP) blended with carrageenan by gamma irradiation at different doses of 25 and 40 kGy. Gel fraction of hydrogels prepared using 10 and 15% PVP in combination with 0.25 and 0.5% carrageenan was evaluated. Based on gel fraction, 15% PVP in combination with 0.25% carrageenan and radiation dose of 25 kGy was selected for the preparation of hydrogels with nanosilver. Radiolytic synthesis of silver nanoparticles within the PVP hydrogel was carried out. The hydrogels with silver nanoparticles were assessed for antimicrobial effectiveness and physical properties of relevance to clinical performance. Fluid handling capacity (FHC) for PVP/carrageenan was 2.35 ± 0.39-6.63 ± 0.63 g/10 cm(2) in 2-24 h. No counts for Pseudomonas aeruginosa, Staphylococcus aureus, Escherichia coli, and Candida albicans were observed in the presence of hydrogels containing 100 ppm nanosilver after 3-6 h. The release of silver from hydrogels containing 100 ppm nanosilver was 20.42 ± 1.98 ppm/100 cm(2) in 24 h. Hydrogels containing 100 ppm nanosilver with efficient FHC demonstrated potential microbicidal activity (≥3 log10 decrease in CFU/ml) against wound pathogens, P. aeruginosa, S. aureus, E. coli, and C. albicans. PVP/carrageenan hydrogels containing silver nanoparticles can be used as wound dressings to control infection and facilitate the healing process for burns and other skin injuries.

  6. Identification of lysozyme activity from two edible bivalves - Perna viridis (Linnaeus) and Meretrix casta (Chemnitz)

    Digital Repository Service at National Institute of Oceanography (India)

    Sharma, S.; Tanu; Chatterji, A.

    Shellfish Immunol., 11, 611–622. Data, S. (2005). Purification of lysozyme from shell liquor of eastern oysters (crassostrea virginica) and its use in antimicrobial films to Preserve smoked fish. Thesis Louisiana State University and Agricultural...

  7. Lysozyme expression in Lactococcus lactis

    NARCIS (Netherlands)

    Guchte, Maarten van de; Wal, Fimme Jan van der; Kok, Jan; Venema, Gerhardus

    1992-01-01

    Three lysozyme-encoding genes, one of eukaryotic and two of prokaryotic origin, were expressed in Lactococcus lactis subsp. lactis. Hen egg white lysozyme (HEL) could be detected in L. lactis lysates by Western blotting. No lysozyme activity was observed, however, presumably because of the absence o

  8. 镀银纤维混纺织物抑菌性能及机理分析%Antimicrobial Property and Mechanism Analysis of Silver-plated Fiber Blended Fabric

    Institute of Scientific and Technical Information of China (English)

    于灵芳; 张华鹏

    2012-01-01

    探讨棉镀银纤维混纺织物的抑菌性能及机理.采用不同含银量的镀银纤维与棉纤维纺制不同混纺比的棉镀银纤维混纺纱,并织制出不同含银量的棉镀银纤维混纺织物,测试了不同含银量、不同洗涤次数、与大肠杆菌不同接触时间的混纺织物对大肠杆菌的抑菌效果,同时测试了不同浸泡时间下混纺织物的银离子释放率.研究结果表明:棉镀银纤维混纺织物中的含银量在2%以上时,其对大肠杆菌的抑菌率可以达到100%;镀银纤维中的银含量、棉镀银纤维混纺比对混纺织物的抑菌效果均有明显的影响;镀银纤维的抑菌效果和镀银纤维表面沉积银层的离子化有关,银离子释放率越高,抑菌效果越明显.%Antimicrobial property and mechanism of cotton silver-plated fiber blended fabric were discussed. Blended yarns were spun by cotton and silver-plated fiber with different silver contents. Blended fabric was woven by the blended yarns. Antibacterial effect of blended fabric to escherichia coli were tested when adopting different silver contents, washing times and contact times. Silver ion release rates of blended fabric in different soaking time were tested. The result shows that antimicrobial rate of blended fabric to escherichia coli can be reach 100% when silver contents in cotton silver-plated fiber blended fabric is over 2%. Antimicrobial effect was effected obviously by sliver contents in silver-plated fiber and cotton silver-plated fiber blending ratio. Antimicrobial effect of silver-plated fiber is related with silver-plated fiber surface sliver layer ionization. The higher silver ion release rate, the more obvious antimicrobial effect will be.

  9. Use of rosemary, oregano, and a commercial blend of essential oils in broiler chickens: in vitro antimicrobial activities and effects on growth performance.

    Science.gov (United States)

    Mathlouthi, N; Bouzaienne, T; Oueslati, I; Recoquillay, F; Hamdi, M; Urdaci, M; Bergaoui, R

    2012-03-01

    The present study was conducted to characterize the in vitro antimicrobial activities of 3 essential oils [oregano, rosemary, and a commercial blend of essential oils (BEO)] against pathogenic and nonpathogenic bacteria and to evaluate their effects on broiler chicken performances. The chemical composition of the essential oils was determined using the gas chromatography interfaced with a mass spectroscopy. The disc diffusion method, the minimum inhibitory concentration (MIC), and the minimum bactericidal concentration (MBC) were applied for the determination of antimicrobial activities of essential oils. In vivo study, a total of seven hundred fifty 1-d-old male broiler chickens were assigned to 6 dietary treatment groups: basal diet (control; CON), CON + 44 mg of avilamycin/kg (A), CON + 100 mg of rosemary essential oil/kg (ROS), CON + 100 mg of oregano essential oil/kg (OR), CON + 50 mg of rosemary and 50 mg of oregano essential oils/kg (RO), and CON + 1,000 mg of BEO/kg (essential oil mixture, EOM). The essential oils isolated from rosemary and oregano were characterized by their greater content of 1,8-cineole (49.99%) and carvacrol (69.55%), respectively. The BEO was mainly represented by the aldehyde (cinnamaldehyde) and the monoterpene (1,8-cineole) chemical groups. The results of the disc diffusion method indicated that the rosemary essential oil had antibacterial activity (P ≤ 0.05) against only 3 pathogenic bacteria, Escherichia coli (8 mm), Salmonella indiana (11 mm), and Listeria innocua (9 mm). The essential oil of oregano had antimicrobial activities (P ≤ 0.05) on the same bacteria as rosemary but also on Staphylococcus aureus (22 mm) and Bacillus subtilis (12 mm). Oregano essential oil had greater (P ≤ 0.05) antimicrobial activities against pathogenic bacteria than rosemary essential oil but they had no synergism between them. The BEO showed an increased antimicrobial activity (P ≤ 0.05) against all studied bacteria (pathogenic and

  10. Chitosan-PLGA polymer blends as coatings for hydroxyapatite nanoparticles and their effect on antimicrobial properties, osteoconductivity and regeneration of osseous tissues.

    Science.gov (United States)

    Ignjatović, Nenad; Wu, Victoria; Ajduković, Zorica; Mihajilov-Krstev, Tatjana; Uskoković, Vuk; Uskoković, Dragan

    2016-03-01

    Composite biomaterials comprising nanostructured hydroxyapatite (HAp) have an enormous potential for natural bone tissue reparation, filling and augmentation. Chitosan (Ch) as a naturally derived polymer has many physicochemical and biological properties that make it an attractive material for use in bone tissue engineering. On the other hand, poly-D,L-lactide-co-glycolide (PLGA) is a synthetic polymer with a long history of use in sustained drug delivery and tissue engineering. However, while chitosan can disrupt the cell membrane integrity and may induce blood thrombosis, PLGA releases acidic byproducts that may cause tissue inflammation and interfere with the healing process. One of the strategies to improve the biocompatibility of Ch and PLGA is to combine them with compounds that exhibit complementary properties. In this study we present the synthesis and characterization, as well as in vitro and in vivo analyses of a nanoparticulate form of HAp coated with two different polymeric systems: (a) Ch and (b) a Ch-PLGA polymer blend. Solvent/non-solvent precipitation and freeze-drying were used for synthesis and processing, respectively, whereas thermogravimetry coupled with mass spectrometry was used for phase identification purposes in the coating process. HAp/Ch composite particles exhibited the highest antimicrobial activity against all four microbial strains tested in this work, but after the reconstruction of the bone defect they also caused inflammatory reactions in the newly formed tissue where the defect had lain. Coating HAp with a polymeric blend composed of Ch and PLGA led to a decrease in the reactivity and antimicrobial activity of the composite particles, but also to an increase in the quality of the newly formed bone tissue in the reconstructed defect area.

  11. Lysozymes in the animal kingdom

    Indian Academy of Sciences (India)

    Lien Callewaert; Chris W Michiels

    2010-03-01

    Lysozymes (EC 3.2.1.17) are hydrolytic enzymes, characterized by their ability to cleave the -(1,4)-glycosidic bond between -acetylmuramic acid and -acetylglucosamine in peptidoglycan, the major bacterial cell wall polymer. In the animal kingdom, three major distinct lysozyme types have been identified – the c-type (chicken or conventional type), the g-type (goose-type) and the i-type (invertebrate type) lysozyme. Examination of the phylogenetic distribution of these lysozymes reveals that c-type lysozymes are predominantly present in the phylum of the Chordata and in different classes of the Arthropoda. Moreover, g-type lysozymes (or at least their corresponding genes) are found in members of the Chordata, as well as in some bivalve mollusks belonging to the invertebrates. In general, the latter animals are known to produce i-type lysozymes. Although the homology in primary structure for representatives of these three lysozyme types is limited, their three-dimensional structures show striking similarities. Nevertheless, some variation exists in their catalytic mechanisms and the genomic organization of their genes. Regarding their biological role, the widely recognized function of lysozymes is their contribution to antibacterial defence but, additionally, some lysozymes (belonging to different types) are known to function as digestive enzymes.

  12. MUCOADHESIVE GEL WITH IMMOBILIZED LYSOZYME: PREPARATION AND PROPERTIES

    Directory of Open Access Journals (Sweden)

    Dekina S. S.

    2015-08-01

    Full Text Available The study of non-covalent immobilized lysozyme, as well as physico-chemical and biochemical properties of obtained mucoadhesive gel was the aim of the research. Lysozyme activity was determined by bacteriolytic method (Micrococcus lysodeikticus cells acetone powder was a substrate. Lysozyme immobilization was conducted by the method of entrapment in gel. Enzyme carrier interaction was studied by viscometric, spectrophotometric and spectrofluorimetric methods. Mucoadhesive gel with immobilized lysozyme, possessing antiinflammatory and antimicrobial activities, was prepared. Due to immobilization, protein-polymer complex with the original enzymatic activity was formed. The product is characterized by high mucoadhesive properties, quantitative retaining of protein and bacteriolytic activity, prolonged release of the enzyme, improved biochemical characteristics (extended pH-activity profile, stability in acidic medium and during storage for 2 years, and it is perspective for further studies. The proposed method for lysozyme immobilization in the carboxymethyl cellulose sodium salt gel allows to obtain a stable, highly efficient product, with high adhesive properties for attachment to the mucous membranes, that is promising for use in biomedicine.

  13. Antimicrobial Efficacy of a Sulfuric Acid and Sodium Sulfate Blend, Peroxyacetic Acid, and Cetylpyridinium Chloride against Salmonella on Inoculated Chicken Wings.

    Science.gov (United States)

    Scott, Brittney R; Yang, Xiang; Geornaras, Ifigenia; Delmore, Robert J; Woerner, Dale R; Reagan, James O; Morgan, J Brad; Belk, Keith E

    2015-11-01

    Studies were conducted to evaluate the efficacy of a commercial blend of sulfuric acid and sodium sulfate (SSS) in reducing Salmonella on inoculated whole chilled chicken wings and to compare its efficacy to peroxyacetic acid (PAA) and cetylpyridinium chloride (CPC). Wings were spot inoculated (5 to 6 log CFU/ml of sample rinsate) with a five-strain mixture of novobiocin- and nalidixic acid-resistant Salmonella and then left untreated (control) or treated by immersing individual wings in 350 ml of antimicrobial solution. An initial study evaluated two treatment immersion times, 10 and 20 s, of SSS (pH 1.1) and compared cell recoveries following rinsing of treated samples with buffered peptone water or Dey/Engley neutralizing broth. In a second study, inoculated wings were treated with SSS (pH 1.1; 20 s), PAA (700 ppm, 20 s), or CPC (4,000 ppm, 10 s) and analyzed for survivors immediately after treatment (0 h) and after 24 h of aerobic storage at 4°C. Color and pH analyses were also conducted in the latter study. Recovery of Salmonella survivors following treatment with SSS (10 or 20 s) was not (P ≥ 0.05) affected by the type of cell recovery rinse solution (buffered peptone water or Dey/Engley neutralizing broth), but there was an effect (P Salmonella at 0 h increased in the order CPC , SSS , PAA; however, after 24 h of aerobic storage, pathogen counts of SSS- and PAA-treated wings did not differ (P ≥ 0.05). Overall, the results indicated that SSS applied at pH 1.1 for 20 s was an effective antimicrobial intervention to reduce Salmonella contamination on chicken wings.

  14. Expression of recombinant human lysozyme in transgenic chicken promotes the growth of Bifidobacterium in the intestine and improves postnatal growth of chicken

    OpenAIRE

    Wang, Hai; Wu, Hongping; Wang, Kejun; Cao, Zhichen; Yu, Kun; Lian, Ling; Lian, Zhengxing

    2016-01-01

    Lysozyme is one kind of antimicrobial proteins and often used as feed additive which can defend against pathogenic bacteria and enhance immune function of animals. In this study, we have injected the lentiviral vector expressing recombinant human lysozyme (rhLZ) gene into the blastoderm of chicken embryo to investigate the effect of recombinant human lysozyme on postnatal intestinal microbiota distribution and growth performance of chicken. Successfully, we generated 194 transgenic chickens i...

  15. Resistance to mucosal lysozyme compensates for the fitness deficit of peptidoglycan modifications by Streptococcus pneumoniae.

    Directory of Open Access Journals (Sweden)

    Kimberly M Davis

    2008-12-01

    Full Text Available The abundance of lysozyme on mucosal surfaces suggests that successful colonizers must be able to evade its antimicrobial effects. Lysozyme has a muramidase activity that hydrolyzes bacterial peptidoglycan and a non-muramidase activity attributable to its function as a cationic antimicrobial peptide. Two enzymes (PgdA, a N-acetylglucosamine deacetylase, and Adr, an O-acetyl transferase that modify different sites on the peptidoglycan of Streptococcus pneumoniae have been implicated in its resistance to lysozyme in vitro. Here we show that the antimicrobial effect of human lysozyme is due to its muramidase activity and that both peptidoglycan modifications are required for full resistance by pneumococci. To examine the contribution of lysozyme and peptidoglycan modifications during colonization of the upper respiratory tract, competition experiments were performed with wild-type and pgdAadr mutant pneumococci in lysozyme M-sufficient (LysM(+/+ and -deficient (LysM(-/- mice. The wild-type strain out-competed the double mutant in LysM(+/+, but not LysM(-/- mice, indicating the importance of resistance to the muramidase activity of lysozyme during mucosal colonization. In contrast, strains containing single mutations in either pgdA or adr prevailed over the wild-type strain in both LysM(+/+ and LysM(-/- mice. Our findings demonstrate that individual peptidoglycan modifications diminish fitness during colonization. The competitive advantage of wild-type pneumococci in LysM(+/+ but not LysM(-/- mice suggests that the combination of peptidoglycan modifications reduces overall fitness, but that this is outweighed by the benefits of resistance to the peptidoglycan degrading activity of lysozyme.

  16. Stomach lysozymes of the three-toed sloth (Bradypus variegatus), an arboreal folivore from the Neotropics.

    Science.gov (United States)

    Pacheco, M Andreína; Concepción, Juan Luís; Rangel, José David Rosales; Ruiz, Marie Christine; Michelangeli, Fabián; Domínguez-Bello, María G

    2007-07-01

    Lysozymes are antimicrobial defences that act as digestive enzymes when expressed in the stomach of herbivores with pre-gastric fermentation. We studied this enzyme in the complex stomach of the three-toed sloth (Bradypus variegatus), a folivore with pre-gastric fermentation. Lysozymes were identified by SDS-PAGE and immunoblotting in all portions: diverticulum, pouch, glandular and muscular prepyloric area with 14.3 kDa of molecular mass. Purified lysozymes from all areas but the diverticulum were characterized by MALDI-TOF, optimal pH, optimal ionic strength, and specific activity. The differences observed suggested at least three isoforms. The optimal pHs were similar to the pH of the stomach portion where the enzymes were isolated. The lysozyme from the pouch (fermentation chamber) exhibited higher specific activity and concentration than the others. The specific activity of the enzyme from the acid muscular prepyloric portion was comparable to that reported in the cow abomasums; however, its concentration was lower than that observed in cow. This distinctive pattern of secretion/specific activity and overall low concentration suggests different roles for the lysozymes in this herbivore compared to Artiodactyla. We postulate that sloth stomach lysozymes may still be antimicrobial defences by protecting the microbial flora of the fermentation chamber against foreign bacteria.

  17. Biophysical aspects of lysozyme adduct with monocrotophos.

    Science.gov (United States)

    Amaraneni, Sreenivasa Rao; Kumar, Sudhir; Gourinath, Samudrala

    2014-09-01

    The present study on in vitro formation and characterization of lysozyme adduct with monocrotophos (MP) evaluates the potential of lysozyme to be used as a sensitive biomarker to monitor exposure levels to the commonly used organophosphorus pesticide monocrotophos. Crystallization of lysozyme protein adduct with monocrotophos was also undertaken to understand the adduct formation mechanism at a molecular level. The binding of organophosphorus pesticides to lysozyme is one of the key steps in their mutagenicity. The formation and structural characterization of lysozyme adduct with monocrotophos was done using MALDI-TOFMS, fluorescence, UV/Vis spectroscopy, circular dichroism, and X-ray diffraction studies. We report the crystal structure of lysozyme adduct with monocrotophos at 1.9 Å. It crystallized in the P43 space group with two monomers in one asymmetric unit having one molecule of monocrotophos bound to each protein chain. The results proved that the fluorescence quenching of lysozyme by monocrotophos is due to binding of monocrotophos with a tryptophan residue of lysozyme. Monocrotophos interacts most strongly with the Trp-108 and Asp-52 of lysozyme. The interactions of the monocrotophos molecule with the lysozyme suggest the formation of a stable adduct. In addition, the alteration of lysozyme secondary structure in the presence of monocrotophos was confirmed by circular dichroism and fluorescence inhibition of lysozyme by increasing monocrotophos and UV/Vis spectrophotometry. The formation of lysozyme adduct with monocrotophos was confirmed by MALDI-TOFMS.

  18. Antibacterial activity of hen egg white lysozyme modified by heat and enzymatic treatments against oenological lactic acid bacteria and acetic acid bacteria.

    Science.gov (United States)

    Carrillo, W; García-Ruiz, A; Recio, I; Moreno-Arribas, M V

    2014-10-01

    The antimicrobial activity of heat-denatured and hydrolyzed hen egg white lysozyme against oenological lactic acid and acetic acid bacteria was investigated. The lysozyme was denatured by heating, and native and heat-denatured lysozymes were hydrolyzed by pepsin. The lytic activity against Micrococcus lysodeikticus of heat-denatured lysozyme decreased with the temperature of the heat treatment, whereas the hydrolyzed lysozyme had no enzymatic activity. Heat-denatured and hydrolyzed lysozyme preparations showed antimicrobial activity against acetic acid bacteria. Lysozyme heated at 90°C exerted potent activity against Acetobacter aceti CIAL-106 and Gluconobacter oxydans CIAL-107 with concentrations required to obtain 50% inhibition of growth (IC50) of 0.089 and 0.013 mg/ml, respectively. This preparation also demonstrated activity against Lactobacillus casei CIAL-52 and Oenococcus oeni CIAL-91 (IC50, 1.37 and 0.45 mg/ml, respectively). The two hydrolysates from native and heat-denatured lysozyme were active against O. oeni CIAL-96 (IC50, 2.77 and 0.3 mg/ml, respectively). The results obtained suggest that thermal and enzymatic treatments increase the antibacterial spectrum of hen egg white lysozyme in relation to oenological microorganisms.

  19. Control of electrostatic interactions between F-actin and genetically modified lysozyme in aqueous media

    Energy Technology Data Exchange (ETDEWEB)

    Sanders, Lori K.; Xian, Wujing; Guaqueta, Camilo; Strohman, Michael J.; Vrasich, Chuck R.; Luijten, Erik; Wong, Gerard C.L. (UIUC)

    2008-07-11

    The aim for deterministic control of the interactions between macroions in aqueous media has motivated widespread experimental and theoretical work. Although it has been well established that like-charged macromolecules can aggregate under the influence of oppositely charged condensing agents, the specific conditions for the stability of such aggregates can only be determined empirically. We examine these conditions, which involve an interplay of electrostatic and osmotic effects, by using a well defined model system composed of F-actin, an anionic rod-like polyelectrolyte, and lysozyme, a cationic globular protein with a charge that can be genetically modified. The structure and stability of actin-lysozyme complexes for different lysozyme charge mutants and salt concentrations are examined by using synchrotron x-ray scattering and molecular dynamics simulations. We provide evidence that supports a structural transition from columnar arrangements of F-actin held together by arrays of lysozyme at the threefold interstitial sites of the actin sublattice to marginally stable complexes in which lysozyme resides at twofold bridging sites between actin. The reduced stability arises from strongly reduced partitioning of salt between the complex and the surrounding solution. Changes in the stability of actin-lysozyme complexes are of biomedical interest because their formation has been reported to contribute to the persistence of airway infections in cystic fibrosis by sequestering antimicrobials such as lysozyme. We present x-ray microscopy results that argue for the existence of actin-lysozyme complexes in cystic fibrosis sputum and demonstrate that, for a wide range of salt conditions, charge-reduced lysozyme is not sequestered in ordered complexes while retaining its bacterial killing activity.

  20. Control of Electrostatic Interactions Between F-Actin And Genetically Modified Lysozyme in Aqueous Media

    Energy Technology Data Exchange (ETDEWEB)

    Sanders, L.K.; Xian, W.; Guaqueta, C.; Strohman, M.; Vrasich, C.R.; Luijten, E.; Wong, G.C.L.

    2009-06-04

    The aim for deterministic control of the interactions between macroions in aqueous media has motivated widespread experimental and theoretical work. Although it has been well established that like-charged macromolecules can aggregate under the influence of oppositely charged condensing agents, the specific conditions for the stability of such aggregates can only be determined empirically. We examine these conditions, which involve an interplay of electrostatic and osmotic effects, by using a well defined model system composed of F-actin, an anionic rod-like polyelectrolyte, and lysozyme, a cationic globular protein with a charge that can be genetically modified. The structure and stability of actin-lysozyme complexes for different lysozyme charge mutants and salt concentrations are examined by using synchrotron x-ray scattering and molecular dynamics simulations. We provide evidence that supports a structural transition from columnar arrangements of F-actin held together by arrays of lysozyme at the threefold interstitial sites of the actin sublattice to marginally stable complexes in which lysozyme resides at twofold bridging sites between actin. The reduced stability arises from strongly reduced partitioning of salt between the complex and the surrounding solution. Changes in the stability of actin-lysozyme complexes are of biomedical interest because their formation has been reported to contribute to the persistence of airway infections in cystic fibrosis by sequestering antimicrobials such as lysozyme. We present x-ray microscopy results that argue for the existence of actin-lysozyme complexes in cystic fibrosis sputum and demonstrate that, for a wide range of salt conditions, charge-reduced lysozyme is not sequestered in ordered complexes while retaining its bacterial killing activity.

  1. The antibacterial protein lysozyme identified as the termite egg recognition pheromone.

    Directory of Open Access Journals (Sweden)

    Kenji Matsuura

    Full Text Available Social insects rely heavily on pheromone communication to maintain their sociality. Egg protection is one of the most fundamental social behaviours in social insects. The recent discovery of the termite-egg mimicking fungus 'termite-ball' and subsequent studies on termite egg protection behaviour have shown that termites can be manipulated by using the termite egg recognition pheromone (TERP, which strongly evokes the egg-carrying and -grooming behaviours of workers. Despite the great scientific and economic importance, TERP has not been identified because of practical difficulties. Herein we identified the antibacterial protein lysozyme as the TERP. We isolated the target protein using ion-exchange and hydrophobic interaction chromatography, and the MALDI-TOF MS analysis showed a molecular size of 14.5 kDa. We found that the TERP provided antibacterial activity against a gram-positive bacterium. Among the currently known antimicrobial proteins, the molecular size of 14.5 kDa limits the target to lysozyme. Termite lysozymes obtained from eggs and salivary glands, and even hen egg lysozyme, showed a strong termite egg recognition activity. Besides eggs themselves, workers also supply lysozyme to eggs through frequent egg-grooming, by which egg surfaces are coated with saliva containing lysozyme. Reverse transcript PCR analysis showed that mRNA of termite lysozyme was expressed in both salivary glands and eggs. Western blot analysis confirmed that lysozyme production begins in immature eggs in queen ovaries. This is the first identification of proteinaceous pheromone in social insects. Researchers have focused almost exclusively on hydrocarbons when searching for recognition pheromones in social insects. The present finding of a proteinaceous pheromone represents a major step forward in, and result in the broadening of, the search for recognition pheromones. This novel function of lysozyme as a termite pheromone illuminates the profound influence

  2. Complex coacervates of hyaluronic acid and lysozyme

    DEFF Research Database (Denmark)

    Water, Jorrit J.; Schack, Malthe M.; Velazquez-Campoy, Adrian

    2014-01-01

    by differential scanning calorimetry. Furthermore, the protein stability of lysozyme was found to be improved upon complexation during a 12-weeks storage study at room temperature, as shown by a significant increase in recovered protein when complexed (94 ± 2% and 102 ± 5% depending on the polymer-protein weight...... stoichiometry was determined using solution depletion and isothermal titration calorimetry. The binding stoichiometry of lysozyme to hyaluronic acid (870 kDa) determined by solution depletion was found to be 225.9 ± 6.6 mol, or 0.1 bound lysozyme molecules per hyaluronic acid monomer. This corresponded well...... with that obtained by isothermal titration calorimetry of 0.09 bound lysozyme molecules per hyaluronic acid monomer. The complexation did not alter the secondary structure of lysozyme measured by Fourier-transform infrared spectroscopy overlap analysis and had no significant impact on the Tm of lysozyme determined...

  3. Blended Learning

    NARCIS (Netherlands)

    Van der Baaren, John

    2009-01-01

    Van der Baaren, J. (2009). Blended Learning. Presentation given at the Mini symposium 'Blended Learning the way to go?'. November, 5, 2009, The Hague, The Netherlands: Netherlands Defence Academy (NDLA).

  4. Blended Learning

    NARCIS (Netherlands)

    Van der Baaren, John

    2009-01-01

    Van der Baaren, J. (2009). Blended Learning. Presentation given at the Mini symposium 'Blended Learning the way to go?'. November, 5, 2009, The Hague, The Netherlands: Netherlands Defence Academy (NDLA).

  5. Lysozyme immobilization onto PVC catheters grafted with NVCL and HEMA for reduction of bacterial adhesion

    Science.gov (United States)

    Guadarrama-Zempoalteca, Yesica; Díaz-Gómez, Luis; Meléndez-Ortiz, H. Iván; Concheiro, Angel; Alvarez-Lorenzo, Carmen; Bucio, Emilio

    2016-09-01

    The aim of the present work was to functionalize poly(vinyl chloride) (PVC) urinary catheters with grafted copolymers that can improve the biocompatibility and serve as binding points of lysozyme. PVC catheters were modified by grafting a mixture of N-vinylcaprolactam (NVCL) and 2-hydroxyethylmethacrylate (HEMA) applying a gamma-ray pre-irradiation method. The effect of absorbed dose, monomer concentration, temperature, and reaction time on the grafting percentage was evaluated. The grafted catheters were characterized regarding surface composition (FTIR-ATR spectroscopy), thermal properties (DSC and TGA) and swelling in aqueous medium. Lysozyme was directly coupled onto PVC-g-(NVCL/HEMA) previously activated using carbonyldiimidazole. Antimicrobial lytic activity of the modified catheters over time was tested against Micrococcus lysodeikticus. Lysozyme diminished the adhesion of Staphylococcus aureus onto the functionalized catheters, which may be suitable to prevent biofilm formation.

  6. Evolution of the mammalian lysozyme gene family

    Directory of Open Access Journals (Sweden)

    Biegel Jason M

    2011-06-01

    Full Text Available Abstract Background Lysozyme c (chicken-type lysozyme has an important role in host defense, and has been extensively studied as a model in molecular biology, enzymology, protein chemistry, and crystallography. Traditionally, lysozyme c has been considered to be part of a small family that includes genes for two other proteins, lactalbumin, which is found only in mammals, and calcium-binding lysozyme, which is found in only a few species of birds and mammals. More recently, additional testes-expressed members of this family have been identified in human and mouse, suggesting that the mammalian lysozyme gene family is larger than previously known. Results Here we characterize the extent and diversity of the lysozyme gene family in the genomes of phylogenetically diverse mammals, and show that this family contains at least eight different genes that likely duplicated prior to the diversification of extant mammals. These duplicated genes have largely been maintained, both in intron-exon structure and in genomic context, throughout mammalian evolution. Conclusions The mammalian lysozyme gene family is much larger than previously appreciated and consists of at least eight distinct genes scattered around the genome. Since the lysozyme c and lactalbumin proteins have acquired very different functions during evolution, it is likely that many of the other members of the lysozyme-like family will also have diverse and unexpected biological properties.

  7. Effect of the incorporation of antimicrobial/antioxidant proteins on the properties of potato starch films.

    Science.gov (United States)

    Moreno, Olga; Atarés, Lorena; Chiralt, Amparo

    2015-11-20

    Glycerol plasticized potato starch films containing bioactive proteins (lactoferrin (LF) and/or lysozyme (LZ), at 0.1 and 0.2 ratio with respect to starch) were obtained by casting method and characterized as to their microstructural, thermal and physical (water content, mechanical, water and oxygen barrier, optical) properties. The bioactive properties, named antioxidant and antimicrobial, of the proteins and the films were also characterized. The incorporation of proteins affected the structural and physical properties of potato starch films, while modifying their thermal behavior and increasing the glass transition temperature. Both proteins showed a certain degree of compatibility with starch chains through the bond formations (increase in Tg), while a part is separated and migrates to the film surface. Their incorporation, especially that of lactoferrin, greatly increased the film's brittleness, regardless of the films water content, although they enhance the water vapor and oxygen barrier properties, whatever the age of the film. Protein also reduced the film's transparency and gloss, while lactoferrin induced color changes. The thermal degradation of blend films and isolated proteins occurred at temperatures of over 250°C, which means that blend starch films can be thermoprocessed, according to their thermoplastic properties and following the usual practices of the plastics industries. A synergistic antimicrobial action against Escherichia coli and coliforms was observed when both LZ and LF were simultaneously applied. Both of these exhibited antioxidant capacity.

  8. The association of lysozyme with casein

    NARCIS (Netherlands)

    Roos, de A.L.; Walstra, P.; Geurts, T.J.

    1998-01-01

    The association of hen eggs’ lysozyme with caseins was studied by using three casein substrates: (I) solutions of the various caseins, (II) artificially made casein micelles of various compositions and (III) caseins adsorbed onto soya-oil emulsion droplets. In solution, lysozyme associated most stro

  9. Complex coacervation of lysozyme and heparin

    DEFF Research Database (Denmark)

    van de Weert, Marco; Andersen, Mia Bendix; Frokjaer, Sven

    2004-01-01

    To characterize complex coacervates/flocculates of lysozyme and heparin in terms of binding stoichiometry and to determine the effect of complexation on protein structure and stability.......To characterize complex coacervates/flocculates of lysozyme and heparin in terms of binding stoichiometry and to determine the effect of complexation on protein structure and stability....

  10. A new family of lysozyme inhibitors contributing to lysozyme tolerance in gram-negative bacteria.

    Directory of Open Access Journals (Sweden)

    Lien Callewaert

    2008-03-01

    Full Text Available Lysozymes are ancient and important components of the innate immune system of animals that hydrolyze peptidoglycan, the major bacterial cell wall polymer. Bacteria engaging in commensal or pathogenic interactions with an animal host have evolved various strategies to evade this bactericidal enzyme, one recently proposed strategy being the production of lysozyme inhibitors. We here report the discovery of a novel family of bacterial lysozyme inhibitors with widespread homologs in gram-negative bacteria. First, a lysozyme inhibitor was isolated by affinity chromatography from a periplasmic extract of Salmonella Enteritidis, identified by mass spectrometry and correspondingly designated as PliC (periplasmic lysozyme inhibitor of c-type lysozyme. A pliC knock-out mutant no longer produced lysozyme inhibitory activity and showed increased lysozyme sensitivity in the presence of the outer membrane permeabilizing protein lactoferrin. PliC lacks similarity with the previously described Escherichia coli lysozyme inhibitor Ivy, but is related to a group of proteins with a common conserved COG3895 domain, some of them predicted to be lipoproteins. No function has yet been assigned to these proteins, although they are widely spread among the Proteobacteria. We demonstrate that at least two representatives of this group, MliC (membrane bound lysozyme inhibitor of c-type lysozyme of E. coli and Pseudomonas aeruginosa, also possess lysozyme inhibitory activity and confer increased lysozyme tolerance upon expression in E. coli. Interestingly, mliC of Salmonella Typhi was picked up earlier in a screen for genes induced during residence in macrophages, and knockout of mliC was shown to reduce macrophage survival of S. Typhi. Based on these observations, we suggest that the COG3895 domain is a common feature of a novel and widespread family of bacterial lysozyme inhibitors in gram-negative bacteria that may function as colonization or virulence factors in bacteria

  11. Salivary lysozyme in smoking alcohol dependent persons.

    Science.gov (United States)

    Waszkiewicz, Napoleon; Zalewska-Szajda, Beata; Zalewska, Anna; Waszkiewicz, Magdalena; Szajda, Slawomir Dariusz; Repka, Bernadeta; Szulc, Agata; Kepka, Alina; Minarowska, Alina; Ladny, Jerzy Robert; Zwierz, Krzysztof

    2012-01-01

    The purpose of this study was to evaluate the effect of chronic alcohol intoxication and smoking on the concentration and output of salivary lysozyme. Thirty seven men participated in the study, including 17 male smoking alcohol-dependent patients after chronic alcohol intoxication (AS), and 20 control non-smoking male social drinkers (CNS) with no history of alcohol abuse or smoking. The level of lysozyme was assessed by the radial immunodiffusion method. Significantly lower lysozyme output in the AS group compared to the CNS group was found. Moreover, gingival index was significantly higher in AS than in the CNS group. It appeared that the reduced salivary lysozyme output was more likely the result of ethanol action than smoking. In conclusion, persons addicted to alcohol and nicotine have a poorer periodontal status than non-smoking social drinkers, which may partially be due to the diminished protective effects of lysozyme present in the saliva.

  12. Polymer blends

    Energy Technology Data Exchange (ETDEWEB)

    Allen, Scott D.; Naik, Sanjeev

    2017-08-22

    The present invention provides, among other things, extruded blends of aliphatic polycarbonates and polyolefins. In one aspect, provided blends comprise aliphatic polycarbonates such as poly(propylene carbonate) and a lesser amount of a crystalline or semicrystalline polymer. In certain embodiments, provided blends are characterized in that they exhibit unexpected improvements in their elongation properties. In another aspect, the invention provides methods of making such materials and applications of the materials in applications such as the manufacture of consumer packaging materials.

  13. Antimicrobiële eiwitten in speeksel

    NARCIS (Netherlands)

    W. van 't Hof; E.C.I. Veerman

    2014-01-01

    Speeksel bevat verschillende eiwitten en peptiden met antimicrobiële eigenschappen. In kwantitatief opzicht de belangrijkste zijn: Daarnaast bevat speeksel ook bacteriebindende eiwitten, onder andere immuunglobulinen, die hun kolonisatie in de mond remmen. Lysozym: breekt mureïne in de celwand af en

  14. Blended learning

    DEFF Research Database (Denmark)

    Staugaard, Hans Jørgen

    2012-01-01

    Forsøg på at indkredse begrebet blended learning i forbindelse med forberedelsen af projekt FlexVid.......Forsøg på at indkredse begrebet blended learning i forbindelse med forberedelsen af projekt FlexVid....

  15. Blended Learning

    Science.gov (United States)

    Imbriale, Ryan

    2013-01-01

    Teachers always have been and always will be the essential element in the classroom. They can create magic inside four walls, but they have never been able to create learning environments outside the classroom like they can today, thanks to blended learning. Blended learning allows students and teachers to break free of the isolation of the…

  16. Blended Learning

    Science.gov (United States)

    Tucker, Catlin; Umphrey, Jan

    2013-01-01

    Catlin Tucker, author of "Blended Learning in Grades 4-12," is an English language arts teacher at Windsor High School in Sonoma County, CA. In this conversation with "Principal Leadership," she defines blended learning as a formal education program in which a student is engaged in active learning in part online where they…

  17. Blended Learning

    Science.gov (United States)

    Imbriale, Ryan

    2013-01-01

    Teachers always have been and always will be the essential element in the classroom. They can create magic inside four walls, but they have never been able to create learning environments outside the classroom like they can today, thanks to blended learning. Blended learning allows students and teachers to break free of the isolation of the…

  18. Adsorption of lysozyme on hyaluronic acid functionalized SBA-15 mesoporous silica: a possible bioadhesive depot system.

    Science.gov (United States)

    Medda, Luca; Casula, Maria F; Monduzzi, Maura; Salis, Andrea

    2014-11-04

    Silica-based ordered mesoporous materials are very attractive matrices to prepare smart depot systems for several kinds of therapeutic agents. This work focuses on the well-known SBA-15 mesoporous silica and lysozyme, an antimicrobial protein. In order to improve the bioadhesion properties of SBA-15 particles, the effect of hyaluronic acid (HA) functionalization on lysozyme adsorption was investigated. SBA-15 samples having high (H-SBA) and low (L-SBA) levels of functionalization were analyzed during the three steps of the preparations: (1) introduction of the -NH2 groups to obtain the SBA-NH2 samples; (2) functionalization with HA to obtain the SBA-HA matrices; (3) adsorption of lysozyme. All silica matrices were characterized through N2-adsorption/desorption isotherms, small-angle X-ray scattering, transmission electron microscopy, thermogravimetric analysis, and Fourier transform infrared spectroscopy. The whole of the experimental data suggests that a high level of functionalization of the silica surface allows for a negligible lysozyme adsorption mainly due to unfavorable electrostatic interactions (H-SBA-NH2) or steric hindrance (H-SBA-HA). A low degree of functionalization of the silica surface brings about a very good performance toward lysozyme adsorption, being 71% (L-SBA-NH2) and 63% (L-SBA-HA) respectively, compared to that observed for original SBA-15. Finally, two different kinetic models--a "pseudo-second order" and a "intraparticle diffusion"--were compared to fit lysozyme adsorption data, the latter being more reliable than the former.

  19. Blended learning

    DEFF Research Database (Denmark)

    Dau, Susanne

    2016-01-01

    Blended Learning has been implemented, evaluated and researched for the last decades within different educational areas and levels. Blended learning has been coupled with different epistemological understandings and learning theories, but the fundamental character and dimensions of learning...... in blended learning are still insufficient. Moreover, blended learning is a misleading concept described as learning, despite the fact that it fundamentally is an instructional and didactic approach (Oliver & Trigwell, 2005) addressing the learning environment (Inglis, Palipoana, Trenhom & Ward, 2011......) instead of the learning processes behind. Much of the existing research within the field seems to miss this perspective. The consequence is a lack of acknowledgement of the driven forces behind the context and the instructional design limiting the knowledge foundation of learning in blended learning. Thus...

  20. Blended Learning

    DEFF Research Database (Denmark)

    Gynther, Karsten

    2012-01-01

    Artiklen giver en grundlæggende introduktion til begrebet blended learning og sætter fokus på didaktiske spørgsmål som: Hvad er blended learning? Hvilke forskellige former ser vi i dag i danske uddannelser? Hvorfor udbydes uddannelser i stigende grad i et blended learning format? Hvilke didaktiske...... principper kan man som underviser tage i brug, når man skal designe et blended learning forløb? Hvad er den grundlæggende didaktiske forskel på tilstedeværelsesundervisning og netbaseret undervisning? Og hvilke kritiske perspektiver er det vigtigt at have med, når en uddannelsesinstitution beslutter sig...... for at re-designe traditionel tilstedeværelsesundervisning til blended learning?...

  1. Blended learning

    DEFF Research Database (Denmark)

    Dau, Susanne

    2016-01-01

    in blended learning are still insufficient. Moreover, blended learning is a misleading concept described as learning, despite the fact that it fundamentally is an instructional and didactic approach (Oliver & Trigwell, 2005) addressing the learning environment (Inglis, Palipoana, Trenhom & Ward, 2011......Blended Learning has been implemented, evaluated and researched for the last decades within different educational areas and levels. Blended learning has been coupled with different epistemological understandings and learning theories, but the fundamental character and dimensions of learning......) instead of the learning processes behind. Much of the existing research within the field seems to miss this perspective. The consequence is a lack of acknowledgement of the driven forces behind the context and the instructional design limiting the knowledge foundation of learning in blended learning. Thus...

  2. Evaluation of lysozyme-HCl for the treatment of chalkbrood disease in honey bee colonies.

    Science.gov (United States)

    Van Haga, A; Keddie, B A; Pernal, S F

    2012-12-01

    Chalkbrood, caused by Ascosphaera apis (Maassen and Claussen) Olive and Spiltor, is a cosmopolitan fungal disease of honey bee larvae (Apis mellifera L.) for which there is no chemotherapeutic control. We evaluated the efficacy of lysozyme-HCl, an inexpensive food-grade antimicrobial extracted from hen egg white, for the treatment of chalkbrood disease in honey bee colonies. Our study compared three doses of lysozyme-HCl in sugar syrup (600, 3,000, and 6,000 mg) administered weekly for 3 wk among chalkbrood-inoculated colonies, colonies that were inoculated but remained untreated, and colonies neither inoculated or treated. Lysozyme-HCl at the highest dose evaluated was found to suppress development of chalkbrood disease in inoculated colonies to levels observed in uninoculated, untreated colonies, and did not adversely affect adult bee survival or brood production. Honey production was significantly negatively correlated with increased disease severity but there were no significant differences in winter survival among treatment groups. Based on our results, lysozyme-HCl appears to be a promising, safe therapeutic agent for the control of chalkbrood in honey bee colonies.

  3. Use of human lysozyme transgenic goat milk in cheese making: effects on lactic acid bacteria performance.

    Science.gov (United States)

    Scharfen, E C; Mills, D A; Maga, E A

    2007-09-01

    Genetically engineered goats expressing elevated levels of the antimicrobial enzyme lysozyme in their milk were developed to improve udder health, product shelf life, and consumer well-being. The purpose of this study was to evaluate the effect of lysozyme on the development of lactic acid bacteria (LAB) throughout the cheese-making process. Raw and pasteurized milk from 7 lysozyme transgenic goats and 7 breed-, age-, and parity-matched nontransgenic controls was transformed into cheeses by using industry methods, and their microbiological load was evaluated. The numbers of colony-forming units of LAB were determined for raw and pasteurized goat milk, whey, and curd at d 2 and at d 6 or 7 of production. Selective plating media were used to enumerate lactococcal species separately from total LAB. Although differences in the mean number of colony-forming units between transgenic and control samples in raw milk, whey, and cheese curd were non-significant for both total LAB and lactococcal species from d 2 of production, a significant decrease was observed in both types of LAB among d 6 transgenic raw milk cheese samples. In pasteurized milk trials, a significant decrease in LAB was observed only in the raw milk of transgenic animals. These results indicate that lysozyme transgenic goat milk is not detrimental to LAB growth during the cheese-making process.

  4. Lysozyme Catalyzes the Formation of Antimicrobial Silver Nanoparticles

    Science.gov (United States)

    2009-04-03

    biomineralization A RT IC LE VOL. 3 ▪ NO. 4 ▪ EBY ET AL. www.acsnano.org984 part of the innate immune system in higher organisms and primarily acts...cationic and am- phiphilic protein that will adsorb to ionic and hydro- phobic surfaces, including metal surfaces.2124 After synthesis in methanol...This result is significant, as the strong ionic interactions be- tween metal nanoparticles normally make it difficult to achieve high concentrations of

  5. Antimicrobial compounds in tears.

    Science.gov (United States)

    McDermott, Alison M

    2013-12-01

    The tear film coats the cornea and conjunctiva and serves several important functions. It provides lubrication, prevents drying of the ocular surface epithelia, helps provide a smooth surface for refracting light, supplies oxygen and is an important component of the innate defense system of the eye providing protection against a range of potential pathogens. This review describes both classic antimicrobial compounds found in tears such as lysozyme and some more recently identified such as members of the cationic antimicrobial peptide family and surfactant protein-D as well as potential new candidate molecules that may contribute to antimicrobial protection. As is readily evident from the literature review herein, tears, like all mucosal fluids, contain a plethora of molecules with known antimicrobial effects. That all of these are active in vivo is debatable as many are present in low concentrations, may be influenced by other tear components such as the ionic environment, and antimicrobial action may be only one of several activities ascribed to the molecule. However, there are many studies showing synergistic/additive interactions between several of the tear antimicrobials and it is highly likely that cooperativity between molecules is the primary way tears are able to afford significant antimicrobial protection to the ocular surface in vivo. In addition to effects on pathogen growth and survival some tear components prevent epithelial cell invasion and promote the epithelial expression of innate defense molecules. Given the protective role of tears a number of scenarios can be envisaged that may affect the amount and/or activity of tear antimicrobials and hence compromise tear immunity. Two such situations, dry eye disease and contact lens wear, are discussed here.

  6. Antimicrobial peptides in Echinoderms

    Directory of Open Access Journals (Sweden)

    C Li

    2010-05-01

    Full Text Available Antimicrobial peptides (AMPs are important immune effector molecules for invertebrates, including echinoderms, which lack a vertebrate-type adaptive immune system. Here we summarize the knowledge of such peptides in echinoderms. Strongylocins are a novel family of cysteine-rich AMPs, recently identified in the sea urchins, Strongylocentrotus droebachiensis and S. purpuratus. Although these molecules present diverse amino acid sequences, they share an identical cysteine arrangement pattern, dissimilar to other known AMPs. A family of heterodimeric AMPs, named centrocins, are also present in S. droebachiensis. Lysozymes and fragments of larger proteins, such as beta-thymocins, actin, histone 2A and filamin A have also been shown to display antimicrobial activities in echinoderms. Future studies on AMPs should be aimed in revealing how echinoderms use these AMPs in the immune response against microbial pathogens.

  7. Acetylated Lysozyme as Impurity in Lysozyme Crystals: Constant Distribution Coefficient

    Science.gov (United States)

    Thomas, B. R.; Chernov, A. A.

    2000-01-01

    Hen egg white lysozyme (HEWL) was acetylated to modify molecular charge keeping the molecular size and weight nearly constant. Two derivatives, A and B, more and less acetylated, respectively, were obtained, separated, purified and added to the solution from which crystals of tetragonal HEWL crystals were grown. Amounts of the A or B impurities added were 0.76, 0.38 and 0.1 milligram per millimeter while HEWL concentration were 20, 30 and 40 milligram per milliliter. The crystals grown in 18 experiments for each impurity were dissolved and quantities of A or B additives in these crystals were analyzed by cation exchange high performance liquid chromatography. All the data for each set of 18 samples with the different impurity and regular HEWL concentrations is well described by one distribution coefficient K = 2.15 plus or minus 0.13 for A and K = 3.42 plus or minus 0.25 for B. The observed independence of the distribution coefficient on both the impurity concentration and supersaturation is explained by the dilution model described in this paper. It shows that impurity adsorption and incorporation rate is proportional to the impurity concentration and that the growth rate is proportional to the crystallizing protein in solution. With the kinetic coefficient for crystallization, beta = 5.10(exp -7) centimeters per second, the frequency at which an impurity molecule near the growing interface irreversibly joins a molecular site on the crystal was found to be 3 1 per second, much higher than the average frequency for crystal molecules. For best quality protein crystals it is better to have low microheterogeneous protein impurity concentration and high supers aturation.

  8. Multiple I-Type Lysozymes in the Hydrothermal Vent Mussel Bathymodiolus azoricus and Their Role in Symbiotic Plasticity.

    Directory of Open Access Journals (Sweden)

    Camille Detree

    Full Text Available The aim of this study was first to identify lysozymes paralogs in the deep sea mussel Bathymodiolus azoricus then to measure their relative expression or activity in different tissue or conditions. B. azoricus is a bivalve that lives close to hydrothermal chimney in the Mid-Atlantic Ridge (MAR. They harbour in specialized gill cells two types of endosymbiont (gram-bacteria: sulphide oxidizing bacteria (SOX and methanotrophic bacteria (MOX. This association is thought to be ruled by specific mechanism or actors of regulation to deal with the presence of symbiont but these mechanisms are still poorly understood. Here, we focused on the implication of lysozyme, a bactericidal enzyme, in this endosymbiosis. The relative expression of Ba-lysozymes paralogs and the global anti-microbial activity, were measured in natural population (Lucky Strike--1700 m, Mid-Atlantic Ridge, and in in situ experimental conditions. B. azoricus individuals were moved away from the hydrothermal fluid to induce a loss of symbiont. Then after 6 days some mussels were brought back to the mussel bed to induce a re-acquisition of symbiotic bacteria. Results show the presence of 6 paralogs in B. azoricus. In absence of symbionts, 3 paralogs are up-regulated while others are not differentially expressed. Moreover the global activity of lysozyme is increasing with the loss of symbiont. All together these results suggest that lysozyme may play a crucial role in symbiont regulation.

  9. Use of lysozyme from chicken egg white as a nitrite replacer in an Italian-type chicken sausage

    Directory of Open Access Journals (Sweden)

    Nalaka Sandun Abeyrathne

    2015-09-01

    Full Text Available Background: Sodium or potassium nitrite is widely used as a curing agent in sausages and other cured meat products. Nitrite has strong antimicrobial and antioxidant effects and generates cured meat color. Nitrite, however, can react with secondary or tertiary amines in meat to form carcinogenic, teratogenic and mutagenic N-nitroso compounds. Several findings have been suggested that high consumption of processed meat may increase the risk of cancer, and emphasized that dietary nitrosamines are positively associated with cancer. Lysozyme is one of the major egg proteins that have antimicrobial and antioxidant characteristics. Therefore, lysozyme can be used in meat processing to prevent microbial growth and oxidative degradation in meat products during storage. This study is focused on evaluating the antimicrobial and antioxidant effects of lysozyme extracted from egg white as a replacer of nitrite in a cooked Italian-type chicken sausage. Methods: Four curing treatments including 100% nitrite (control, 100% lysozyme (treatment 1, 25% nitrite + 75% lysozyme (treatment 2 and 50% nitrite + 50% lysozyme (treatment 3 were used to prepare Italian-type chicken sausage samples. Recipe was developed with 64% (w/w meat, 17% (w/w binder (bread crumble, 12% (w/w ice, 4% (w/w vegetable oil, 2% (w/w salt, 1% (w/w spices (chili, black pepper, cardamom. Prepared samples were cooked in an 80 °C smoke house to a core temperature of 65 °C and cooled in cold water to 20-25 °C subsequently packed in polyethylene and stored in a freezer (-18 °C. The antimicrobial effect lysozyme was tested using Escherichia coli and Salmonella. The growth of these pathogens at 0, 3 and 5 days of storage of spore inoculation was determined. The antioxidant activity of lysozyme was determined using the TBARS value during the 25 d storage period. The redness (a*, lightness (L*, and yellowness (b* of sausages were analyzed using a Minolta color meter (CR 410, Konica Minolta Inc

  10. Hydrophobic nano-carrier for lysozyme adsorption

    Indian Academy of Sciences (India)

    CANAN ALTUNBAS; FULDEN ZEYNEP URAL; MURAT UYGUN; NESIBE AVCIBASI; UGUR AVCIBASI; DENIZ AKTAS UYGUN; SINAN AKGÖL

    2016-04-01

    In this work, poly(HEMA–APH) nanoparticles were synthesized by surfactant-free emulsion polymerization technique.Magnetic behaviour was introduced by simple addition of Fe$_3$O$_4$ into the polymerization medium.Characterization of the nanoparticle was carried out by FTIR, ESR, SEM, AFM and EDX analyses. These synthesized magnetic nanoparticles were used for adsorption of lysozyme. For this purpose, adsorption conditions wereoptimized and maximum lysozyme binding capacity was found to be 278.8 mg g$^{−1}$ polymer in pH 7.0 phosphate buffer at 25$^{\\circ}$C. Desorption and reusability properties of the nanoparticles were investigated and lysozyme adsorption efficiency did not change significantly at the end of the 10 successive reuses.

  11. Protein release from electrospun nonwovens: improving the release characteristics through rational combination of polyester blend matrices with polidocanol.

    Science.gov (United States)

    Puhl, Sebastian; Ilko, David; Li, Linhao; Holzgrabe, Ulrike; Meinel, Lorenz; Germershaus, Oliver

    2014-12-30

    Nonwoven scaffolds consisting of poly-ε-caprolactone (PCL), poly(lactic-co-glycolic acid) (PLGA) and polidocanol (PD), and loaded with lysozyme crystals were prepared by electrospinning. The composition of the matrix was varied and the effect of PD content in binary mixtures, and of PD and PLGA content in ternary mixtures regarding processability, fiber morphology, water sorption, swelling and drug release was investigated. Binary PCL/PD blend nonwovens showed a PD-dependent increase in swelling of up to 30% and of lysozyme burst release of up to 45% associated with changes of the fiber morphology. Furthermore, addition of free PD to the release medium resulted in a significant increase of lysozyme burst release from pure PCL nonwovens from approximately 2-35%. Using ternary PCL/PD/PLGA blends, matrix degradation could be significantly improved over PCL/PD blends, resulting in a biphasic release of lysozyme with constant release over 9 weeks, followed by constant release with a reduced rate over additional 4 weeks. Based on these results, protein release from PCL scaffolds is improved by blending with PD due to improved lysozyme desorption from the polymer surface and PD-dependent matrix swelling. Copyright © 2014 Elsevier B.V. All rights reserved.

  12. Recombinant goose-type lysozyme in channel catfish: Lysozyme activity and efficacy as plasmid DNA immunostimulant against Aeromonas hydrophila infection

    Science.gov (United States)

    The objectives of this study were: 1) to investigate whether recombinant channel catfish lysozyme g (CC-Lys-g) produced in E. coli expression system possesses any lysozyme activity; and 2) to evaluate whether channel catfish lysozyme g plasmid DNA could be used as an immunostimulant to protect chann...

  13. Chitosan films and blends for packaging material

    NARCIS (Netherlands)

    Broek, van den L.A.M.; Knoop, J.R.I.; Kappen, F.H.J.; Boeriu, C.G.

    2015-01-01

    An increased interest for hygiene in everyday life as well as in food, feed and medical issues lead to a strong interest in films and blends to prevent the growth and accumulation of harmful bacteria. A growing trend is to use synthetic and natural antimicrobial polymers, to provide non-migratory

  14. Chitosan films and blends for packaging material

    NARCIS (Netherlands)

    Broek, van den L.A.M.; Knoop, J.R.I.; Kappen, F.H.J.; Boeriu, C.G.

    2015-01-01

    An increased interest for hygiene in everyday life as well as in food, feed and medical issues lead to a strong interest in films and blends to prevent the growth and accumulation of harmful bacteria. A growing trend is to use synthetic and natural antimicrobial polymers, to provide non-migratory an

  15. Aptamer-Based Electrochemical Sensing of Lysozyme

    Directory of Open Access Journals (Sweden)

    Alina Vasilescu

    2016-06-01

    Full Text Available Protein analysis and quantification are required daily by thousands of laboratories worldwide for activities ranging from protein characterization to clinical diagnostics. Multiple factors have to be considered when selecting the best detection and quantification assay, including the amount of protein available, its concentration, the presence of interfering molecules, as well as costs and rapidity. This is also the case for lysozyme, a 14.3-kDa protein ubiquitously present in many organisms, that has been identified with a variety of functions: antibacterial activity, a biomarker of several serious medical conditions, a potential allergen in foods or a model of amyloid-type protein aggregation. Since the design of the first lysozyme aptamer in 2001, lysozyme became one of the most intensively-investigated biological target analytes for the design of novel biosensing concepts, particularly with regards to electrochemical aptasensors. In this review, we discuss the state of the art of aptamer-based electrochemical sensing of lysozyme, with emphasis on sensing in serum and real samples.

  16. Lysozyme uptake by oxidized starch polymer microgels

    NARCIS (Netherlands)

    Li, Y.; Vries, R.D.; Kleijn, M.; Slaghek, T.; Timmermans, J.; Stuart, M.C.; Norde, W.

    2010-01-01

    With the aim of determining suitable conditions for uptake and release of globular proteins on microgels, we studied the interaction between phosphated, highly cross-linked, negatively charged oxidized potato starch polymer (OPSP) microgel particles and lysozyme from hen eggs. Our microgel shows a

  17. Complex coacervates of hyaluronic acid and lysozyme

    DEFF Research Database (Denmark)

    Water, Jorrit J.; Schack, Malthe M.; Velazquez-Campoy, Adrian;

    2014-01-01

    Complex coacervates of hyaluronic acid and lysozyme, a model protein, were formed by ionic interaction using bulk mixing and were characterized in terms of binding stoichiometry and protein structure and stability. The complexes were formed at pH 7.2 at low ionic strength (6 mM) and the binding s...

  18. Modeling growth of Alicyclobacillus acidoterrestris DSM 3922 type strain vegetative cells in the apple juice with nisin and lysozyme

    Directory of Open Access Journals (Sweden)

    Celenk Molva

    2017-05-01

    Full Text Available In the present study, the effect of storage temperature on A. acidoterrestris DSM 3922 cells (105 CFU/mL was examined during growth in reconstituted apple juice (pH 3.8, °Brix 11.3 containing nisin (0–100 IU/mL and lysozyme (0–100 mg/L. The growth curves were obtained at three temperatures of 27, 35 and 43 °C using absorbance data (OD600 nm. Based on the results, the minimal inhibitory concentrations (MICs of nisin were found as 10 IU/mL at all tested temperatures. On the other hand, increasing the temperature decreased the amount of lysozyme for growth inhibition. The MICs of lysozyme were found as 10, 2.5 and 1.25 mg/L at 27, 35 and 43 °C, respectively. At selected non-inhibitory doses, nisin (1.25–5 IU/mL and lysozyme (0.3–2.5 mg/L prolonged the lag time compared to the controls at the corresponding temperatures. In addition, there was a strong linear relationship between the lag time and lysozyme concentrations at 27 and 35 °C (R2 > 0.98. The results of this study demonstrated that both nisin and lysozyme could be used to inhibit the growth of A. acidoterrestris cells in the apple juice. The results also indicated that the growth parameters were variable depending on the storage temperature and the type of the antimicrobial agent used in the apple juice.

  19. Lysozymes and lysozyme-like proteins from the fall armyworm, Spodoptera frugiperda.

    Science.gov (United States)

    Chapelle, Michael; Girard, Pierre-Alain; Cousserans, François; Volkoff, Nathalie-Anne; Duvic, Bernard

    2009-12-01

    Lysozyme is an important component of the insect non-specific immune response against bacteria that is characterized by its ability to break down bacterial cell-walls. By searching an EST database from the fall armyworm, Spodoptera frugiperda (Negre et al., 2006), we identified five sequences encoding proteins of the lysozyme family. The deduced protein sequences corresponded to three classical c-type lysozymes Sf-Lys1, Sf-Lys2 and Sf-Lys3, and two lysozyme-like proteins, Sf-LLP1 and Sf-LLP2. Sf-Lys1 was purified from the hemolymph of Escherichia coli-challenged S. frugiperda larvae. The mature protein had a molecular mass of 13.975 Da with an isoelectric point of 8.77 and showed 98.3% and 96.7% identity with lysozymes from Spodoptera litura and Spodoptera exigua, respectively. As the other insect lysozymes, Sf-Lys1 was active against gram positive bacteria such as Micrococcus luteus but also induced a slight permeabilization of the inner membrane of E. coli. Genes encoding these five Sf-Lys or Sf-LLPs were differentially up-regulated in three immune-competent tissues (hemocytes, fat body and gut) after challenges with non-pathogenic bacteria, E. coli and M. luteus, or entomopathogenic bacterium, Photorhabdus luminescens. Sf-Lys1 and Sf-Lys2 were mainly induced in fat body in the presence of E. coli or P. luminescens. Sf-Lys3, which had an acidic isoelectric point, was found to be the most up-regulated of all five Sf-Lys or Sf-LLPs in hemocytes and gut after challenge with P. luminescens. More molecular data are now available to investigate differences in physiological functions of these different members of the lysozyme superfamily.

  20. Antimicrobial Efficacy of a Lactic Acid and Citric Acid Blend against Shiga Toxin-Producing Escherichia coli, Salmonella, and Nonpathogenic Escherichia coli Biotype I on Inoculated Prerigor Beef Carcass Surface Tissue.

    Science.gov (United States)

    Scott, Brittney R; Yang, Xiang; Geornaras, Ifigenia; Delmore, Robert J; Woerner, Dale R; Adler, Jeremy M; Belk, Keith E

    2015-12-01

    Studies were conducted to (i) determine whether inoculants of nonpathogenic Escherichia coli biotype I effectively served as surrogates for E. coli O157:H7, non-O157 Shiga toxin-producing E. coli, and Salmonella when prerigor beef carcass tissue was treated with a commercially available blend of lactic acid and citric acid (LCA) at a range of industry conditions of concentration, temperature, and pressure; (ii) determine the antimicrobial efficacy of LCA; and (iii) investigate the use of surrogates to validate a hot water and LCA sequential treatment as a carcass spray intervention in a commercial beef harvest plant. In an initial laboratory study, beef brisket tissue samples were left uninoculated or were inoculated (∼6 log CFU/cm(2)) on the adipose side with E. coli O157:H7 (5-strain mixture), non-O157 Shiga toxin-producing E. coli (12-strain mixture), Salmonella (6-strain mixture), or nonpathogenic E. coli (5-strain mixture). Samples were left untreated (control) or were treated with LCA, in a spray cabinet, at one of eight combinations of solution concentration (1.9 and 2.5%), solution temperature (43 and 60°C), and application pressure (15 and 30 lb/in(2)). In a second study, the E. coli surrogates were inoculated (∼6 log CFU/cm(2)) on beef carcasses in a commercial facility to validate the use of a hot water treatment (92.2 to 92.8°C, 13 to 15 lb/in(2)) followed by an LCA treatment (1.9%, 50 to 51.7°C, 13 to 15 lb/in(2), 10 s). In the in vitro study, surrogate and pathogen bacteria did not differ in their response to the tested LCA treatments. Treatment with LCA reduced (P < 0.05) inoculated populations by 0.9 to 1.5 log CFU/cm(2), irrespective of inoculum type. The hot water and LCA sequential treatments evaluated in the commercial facility reduced (P < 0.05) the inoculated nonpathogenic E. coli surrogates on carcasses by 3.7 log CFU/cm(2). This study therefore provides the meat industry with data for this sequential multiple hurdle system for the

  1. Production of human lactoferrin and lysozyme in the milk of transgenic dairy animals: past, present, and future.

    Science.gov (United States)

    Cooper, Caitlin A; Maga, Elizabeth A; Murray, James D

    2015-08-01

    Genetic engineering, which was first developed in the 1980s, allows for specific additions to animals' genomes that are not possible through conventional breeding. Using genetic engineering to improve agricultural animals was first suggested when the technology was in the early stages of development by Palmiter et al. (Nature 300:611-615, 1982). One of the first agricultural applications identified was generating transgenic dairy animals that could produce altered or novel proteins in their milk. Human milk contains high levels of antimicrobial proteins that are found in low concentrations in the milk of ruminants, including the antimicrobial proteins lactoferrin and lysozyme. Lactoferrin and lysozyme are both part of the innate immune system and are secreted in tears, mucus, and throughout the gastrointestinal (GI) tract. Due to their antimicrobial properties and abundance in human milk, multiple lines of transgenic dairy animals that produce either human lactoferrin or human lysozyme have been developed. The focus of this review is to catalogue the different lines of genetically engineered dairy animals that produce either recombinant lactoferrin or lysozyme that have been generated over the years as well as compare the wealth of research that has been done on the in vitro and in vivo effects of the milk they produce. While recent advances including the development of CRISPRs and TALENs have removed many of the technical barriers to predictable and efficient genetic engineering in agricultural species, there are still many political and regulatory hurdles before genetic engineering can be used in agriculture. It is important to consider the substantial amount of work that has been done thus far on well established lines of genetically engineered animals evaluating both the animals themselves and the products they yield to identify the most effective path forward for future research and acceptance of this technology.

  2. Preparation of lysozyme molecularly imprinted polymers and purification of lysozyme from egg white.

    Science.gov (United States)

    Wang, Xuejiao; Dong, Shaohua; Bai, Quan

    2014-06-01

    Molecular imprinting as a promising and facile separation technique has received much attention because of its high selectivity for target molecules. In this study, lysozyme molecularly imprinted polymers (Lys-MIPs) were successfully prepared by the entrapment method with lysozyme as the template molecule, acrylamide as the functional monomer and N,N-methylenebisacrylamide as the cross-linker. The removal of the template lysozyme from the molecularly imprinted polymers was investigated in detail by two methods. The synthesized Lys-MIPs were characterized by scanning electron microscopy and Fourier transform-infrared, and the adsorption capacity, selectivity and reproducibility of the Lys-MIPs were also evaluated. The maximum adsorption capacity reached 94.8 mg/g, which is twice that of nonmolecularly imprinted polymers, and satisfactory selectivity and reproducibility were achieved. Using the Lys-MIP column, lysozyme could be separated completely from egg white, with purity close to 100% and mass recovery of 98.2%. This illustrated that the synthesized Lys-MIPs had high specific recognition and selectivity to the template lysozyme when they were applied to a mixture of protein standards and a real sample.

  3. Solid lipid particles for oral delivery of peptide and protein drugs I - Elucidating the release mechanism of lysozyme during lipolysis

    DEFF Research Database (Denmark)

    Christophersen, Philip Carsten B; Zhang, L.; Yang, M

    2013-01-01

    The mechanism of protein release from solid lipid particles was investigated by a new lipolysis model in a biorelevant medium containing both bile salts and phospholipids. Lysozyme, a model protein, was formulated into solid lipid particles using four different types of lipids, two triglycerides...... with different chain-length of fatty acyl groups i.e. trimyristin (TG14) and tristearin (TG18), and two lipid blends dominated by diglycerides and monoglycerides, respectively. The release of lysozyme from the solid lipid particles and the lipid hydrolysis process were assessed in the lipolysis model, while...... the drug release mechanism from solid lipid particles and can potentially be used in rational selection of lipid excipients for oral delivery of peptide/protein drugs....

  4. Basal Secretion of Lysozyme from Human Airways in Vitro

    Directory of Open Access Journals (Sweden)

    Patricia Roger

    1999-01-01

    Full Text Available The aim of this study was to examine the basal release of lysozyme from isolated human lung tissues. Measurements of lysozyme in the fluids derived from lung preparations were performed using a rate-of-lysis assay subsequent to acidification of the biological samples. Lysozyme released from bronchial preparations into fluids was greater than that observed for parenchymal tissues. The lysozyme quantities detected in bronchial fluids were not modified by removal of the surface epithelium. Furthermore, the quantities of lysozyme in bronchial fluids was correlated with the size of the bronchial preparations. These results suggest that the lysozyme was principally secreted by the human bronchi (submucosal layer rather than by parenchyma tissues and that a greater release was observed in the proximal airways.

  5. Triclosan antimicrobial polymers

    Directory of Open Access Journals (Sweden)

    Richard C. Petersen

    2016-03-01

    Full Text Available Triclosan antimicrobial molecular fluctuating energies of nonbonding electron pairs for the oxygen atom by ether bond rotations are reviewed with conformational computational chemistry analyses. Subsequent understanding of triclosan alternating ether bond rotations is able to help explain several material properties in Polymer Science. Unique bond rotation entanglements between triclosan and the polymer chains increase both the mechanical properties of polymer toughness and strength that are enhanced even better through secondary bonding relationships. Further, polymer blend compatibilization is considered due to similar molecular relationships and polarities. With compatibilization of triclosan in polymers a more uniform stability for nonpolar triclosan in the polymer solid state is retained by the antimicrobial for extremely low release with minimum solubility into aqueous solution. As a result, triclosan is projected for long extended lifetimes as an antimicrobial polymer additive. Further, triclosan rapid alternating ether bond rotations disrupt secondary bonding between chain monomers in the resin state to reduce viscosity and enhance polymer blending. Thus, triclosan is considered for a polymer additive with multiple properties to be an antimicrobial with additional benefits as a nonpolar toughening agent and a hydrophobic wetting agent. The triclosan material relationships with alternating ether bond rotations are described through a complete different form of medium by comparisons with known antimicrobial properties that upset bacterial cell membranes through rapid fluctuating mechanomolecular energies. Also, triclosan bond entanglements with secondary bonding can produce structural defects in weak bacterial lipid membranes requiring pliability that can then interfere with cell division. Regarding applications with polymers, triclosan can be incorporated by mixing into a resin system before cure, melt mixed with thermoplastic polymers

  6. Triclosan antimicrobial polymers

    Science.gov (United States)

    Petersen, Richard C.

    2016-01-01

    Triclosan antimicrobial molecular fluctuating energies of nonbonding electron pairs for the oxygen atom by ether bond rotations are reviewed with conformational computational chemistry analyses. Subsequent understanding of triclosan alternating ether bond rotations is able to help explain several material properties in Polymer Science. Unique bond rotation entanglements between triclosan and the polymer chains increase both the mechanical properties of polymer toughness and strength that are enhanced even better through secondary bonding relationships. Further, polymer blend compatibilization is considered due to similar molecular relationships and polarities. With compatibilization of triclosan in polymers a more uniform stability for nonpolar triclosan in the polymer solid state is retained by the antimicrobial for extremely low release with minimum solubility into aqueous solution. As a result, triclosan is projected for long extended lifetimes as an antimicrobial polymer additive. Further, triclosan rapid alternating ether bond rotations disrupt secondary bonding between chain monomers in the resin state to reduce viscosity and enhance polymer blending. Thus, triclosan is considered for a polymer additive with multiple properties to be an antimicrobial with additional benefits as a nonpolar toughening agent and a hydrophobic wetting agent. The triclosan material relationships with alternating ether bond rotations are described through a complete different form of medium by comparisons with known antimicrobial properties that upset bacterial cell membranes through rapid fluctuating mechanomolecular energies. Also, triclosan bond entanglements with secondary bonding can produce structural defects in weak bacterial lipid membranes requiring pliability that can then interfere with cell division. Regarding applications with polymers, triclosan can be incorporated by mixing into a resin system before cure, melt mixed with thermoplastic polymers that set on cooling

  7. Lysozyme-coated silver nanoparticles for differentiating bacterial strains on the basis of antibacterial activity

    Science.gov (United States)

    Ashraf, Sumaira; Chatha, Mariyam Asghar; Ejaz, Wardah; Janjua, Hussnain Ahmed; Hussain, Irshad

    2014-10-01

    Lysozyme, an antibacterial enzyme, was used as a stabilizing ligand for the synthesis of fairly uniform silver nanoparticles adopting various strategies. The synthesized particles were characterized using UV-visible spectroscopy, FTIR, dynamic light scattering (DLS), and TEM to observe their morphology and surface chemistry. The silver nanoparticles were evaluated for their antimicrobial activity against several bacterial species and various bacterial strains within the same species. The cationic silver nanoparticles were found to be more effective against Pseudomonas aeruginosa 3 compared to other bacterial species/strains investigated. Some of the bacterial strains of the same species showed variable antibacterial activity. The difference in antimicrobial activity of these particles has led to the conclusion that antimicrobial products formed from silver nanoparticles may not be equally effective against all the bacteria. This difference in the antibacterial activity of silver nanoparticles for different bacterial strains from the same species may be due to the genome islands that are acquired through horizontal gene transfer (HGT). These genome islands are expected to possess some genes that may encode enzymes to resist the antimicrobial activity of silver nanoparticles. These silver nanoparticles may thus also be used to differentiate some bacterial strains within the same species due to variable silver resistance of these variants, which may not possible by simple biochemical tests.

  8. Lysozyme Photochemistry as a Function of Temperature. The Protective Effect of Nanoparticles on Lysozyme Photostability

    Science.gov (United States)

    Oliveira Silva, Catarina; Petersen, Steffen B.; Pinto Reis, Catarina; Rijo, Patrícia; Molpeceres, Jesús; Vorum, Henrik; Neves-Petersen, Maria Teresa

    2015-01-01

    The presence of aromatic residues and their close spatial proximity to disulphide bridges makes hen egg white lysozyme labile to UV excitation. UVB induced photo-oxidation of tryptophan and tyrosine residues leads to photochemical products, such as, kynurenine, N–formylkynurenine and dityrosine and to the disruption of disulphide bridges in proteins. We here report that lysozyme UV induced photochemistry is modulated by temperature, excitation power, illumination time, excitation wavelength and by the presence of plasmonic quencher surfaces, such as gold, and by the presence of natural fluorescence quenchers, such as hyaluronic acid and oleic acid. We show evidence that the photo-oxidation effects triggered by 295 nm at 20°C are reversible and non-reversible at 10°C, 25°C and 30°C. This paper provides evidence that the 295 nm damage threshold of lysozyme lies between 0.1 μW and 0.3 μW. Protein conformational changes induced by temperature and UV light have been detected upon monitoring changes in the fluorescence emission spectra of lysozyme tryptophan residues and SYPRO® Orange. Lysozyme has been conjugated onto gold nanoparticles, coated with hyaluronic acid and oleic acid (HAOA). Steady state and time resolved fluorescence studies of free and conjugated lysozyme onto HAOA gold nanoparticles reveals that the presence of the polymer decreased the rate of the observed photochemical reactions and induced a preference for short fluorescence decay lifetimes. Size and surface charge of the HAOA gold nanoparticles have been determined by dynamic light scattering and zeta potential measurements. TEM analysis of the particles confirms the presence of a gold core surrounded by a HAOA matrix. We conclude that HAOA gold nanoparticles may efficiently protect lysozyme from the photochemical effects of UVB light and this nanocarrier could be potentially applied to other proteins with clinical relevance. In addition, this study confirms that the temperature plays a

  9. A highly amyloidogenic region of hen lysozyme.

    Science.gov (United States)

    Frare, Erica; Polverino De Laureto, Patrizia; Zurdo, Jesús; Dobson, Christopher M; Fontana, Angelo

    2004-07-23

    Amyloid fibrils obtained after incubating hen egg-white lysozyme (HEWL) at pH 2.0 and 65 degrees C for extended periods of time have been found to consist predominantly of fragments of the protein corresponding to residues 49-100, 49-101, 53-100 and 53-101, derived largely from the partial acid hydrolysis of Asp-X peptide bonds. These internal fragments of HEWL encompass part of the beta-domain and all the residues forming the C-helix in the native protein, and contain two internal disulfide bridges Cys64-Cys80 and Cys76-Cys94. The complementary protein fragments, including helices A, B and D of the native protein, are not significantly incorporated into the network of fibrils, but remain largely soluble, in agreement with their predicted lower propensities to aggregate. Further analysis of the properties of different regions of HEWL to form amyloid fibrils was carried out by studying fragments produced by limited proteolysis of the protein by pepsin. Here, we show that only fragment 57-107, but not fragment 1-38/108-129, is able to generate well-defined amyloid fibrils under the conditions used. This finding is of particular importance, as the beta-domain and C-helix of the highly homologous human lysozyme have been shown to unfold locally in the amyloidogenic variant D67H, which is associated with the familial cases of systemic amyloidosis linked to lysozyme deposition. The identification of the highly amyloidogenic character of this region of the polypeptide chain provides strong support for the involvement of partially unfolded species in the initiation of the aggregation events that lead to amyloid deposition in clinical disease.

  10. Adaptive functional diversification of lysozyme in insectivorous bats.

    Science.gov (United States)

    Liu, Yang; He, Guimei; Xu, Huihui; Han, Xiuqun; Jones, Gareth; Rossiter, Stephen J; Zhang, Shuyi

    2014-11-01

    The role of gene duplication in generating new genes and novel functions is well recognized and is exemplified by the digestion-related protein lysozyme. In ruminants, duplicated chicken-type lysozymes facilitate the degradation of symbiotic bacteria in the foregut. Chicken-type lysozyme has also been reported to show chitinase-like activity, yet no study has examined the molecular evolution of lysozymes in species that specialize on eating insects. Insectivorous bats number over 900 species, and lysozyme expression in the mouths of some of these species is associated with the ingestion of insect cuticle, suggesting a chitinase role. Here, we show that chicken-type lysozyme has undergone multiple duplication events in a major family of insect-eating bats (Vespertilionidae) and that new duplicates have undergone molecular adaptation. Examination of duplicates from two insectivorous bats-Pipistrellus abramus and Scotophilus kuhlii-indicated that the new copy was highly expressed in the tongue, whereas the other one was less tissue-specific. Functional assays applied to pipistrelle lysozymes confirmed that, of the two copies, the tongue duplicate was more efficient at breaking down glycol chitin, a chitin derivative. These results suggest that the evolution of lysozymes in vespertilionid bats has likely been driven in part by natural selection for insectivory.

  11. Action of egg white lysozyme on Clostridium tyrobutyricum.

    Science.gov (United States)

    Wasserfall, F; Teuber, M

    1979-08-01

    A 500-U ml-1 portion of egg white lysozyme was able to kill 99% of 5 X 10(5) resting vegetative cells of Clostridium tyrobutyricum within 24 h of incubation at 25 degrees C. Spores were completely resistant to lysozyme. Proliferating vegetative cells were severely inhibited, although lysozyme-resistant cells developed in growing cultures in the presence of lysozyme. Whereas early stages of spore germination (loss of optical refractility and heat resistance) were not inhibited by lysozyme, the overall outgrowth of spore cells into vegetative cells was delayed by 1 day in the presence of 500 U of lysosyme ml-1. This delay was independent of the lysozyme sensitivity or resistance of the mother culture of the used spores. It is suggested that this inhibition by lysozyme of the outgrowth of spore cells into vegetative cells of the lactate-fermenting C. tyrobutyricum is the basis for the observation that lysozyme can substitute for nitrate in preventing the "late gas" defect of Edam- and Gouda-type cheeses.

  12. Co-option of bacteriophage lysozyme genes by bivalve genomes

    Science.gov (United States)

    Wang, Chunyang; Jin, Min; Lan, Jiangfeng; Ye, Ting; Hui, Kaimin; Tan, Jingmin; Wang, Zheng; Wang, Wen; Han, Guan-Zhu

    2017-01-01

    Eukaryotes have occasionally acquired genetic material through horizontal gene transfer (HGT). However, little is known about the evolutionary and functional significance of such acquisitions. Lysozymes are ubiquitous enzymes that degrade bacterial cell walls. Here, we provide evidence that two subclasses of bivalves (Heterodonta and Palaeoheterodonta) acquired a lysozyme gene via HGT, building on earlier findings. Phylogenetic analyses place the bivalve lysozyme genes within the clade of bacteriophage lysozyme genes, indicating that the bivalves acquired the phage-type lysozyme genes from bacteriophages, either directly or through intermediate hosts. These bivalve lysozyme genes underwent dramatic structural changes after their co-option, including intron gain and fusion with other genes. Moreover, evidence suggests that recurrent gene duplication occurred in the bivalve lysozyme genes. Finally, we show the co-opted lysozymes exhibit a capacity for antibacterial action, potentially augmenting the immune function of related bivalves. This represents an intriguing evolutionary strategy in the eukaryote–microbe arms race, in which the genetic materials of bacteriophages are co-opted by eukaryotes, and then used by eukaryotes to combat bacteria, using a shared weapon against a common enemy. PMID:28100665

  13. Effects of single-walled carbon nanotubes on lysozyme gelation.

    Science.gov (United States)

    Tardani, Franco; La Mesa, Camillo

    2014-09-01

    The possibility to disperse carbon nanotubes in biocompatible matrices has got substantial interest from the scientific community. Along this research line, the inclusion of single walled carbon nanotubes in lysozyme-based hydrogels was investigated. Experiments were performed at different nanotube/lysozyme weight ratios. Carbon nanotubes were dispersed in protein solutions, in conditions suitable for thermal gelation. The state of the dispersions was determined before and after thermal treatment. Rheology, dynamic light scattering and different microscopies investigated the effect that carbon nanotubes exert on gelation. The gelation kinetics and changes in gelation temperature were determined. The effect of carbon and lysozyme content on the gel properties was, therefore, determined. At fixed lysozyme content, moderate amounts of carbon nanotubes do not disturb the properties of hydrogel composites. At moderately high volume fractions in carbon nanotubes, the gels become continuous in both lysozyme and nanotubes. This is because percolating networks are presumably formed. Support to the above statements comes by rheology.

  14. Inhibitory activity of reuterin, nisin, lysozyme and nitrite against vegetative cells and spores of dairy-related Clostridium species.

    Science.gov (United States)

    Avila, Marta; Gómez-Torres, Natalia; Hernández, Marta; Garde, Sonia

    2014-02-17

    The butyric acid fermentation, responsible for late blowing of cheese, is caused by the outgrowth in cheese of some species of Clostridium, resulting in texture and flavor defects and economical losses. The aim of this study was to evaluate the effectiveness of different antimicrobial compounds against vegetative cells and spores of C. tyrobutyricum, C. butyricum, C. beijerinckii and C. sporogenes strains isolated from cheeses with late blowing defect. Minimal inhibitory concentration (MIC) for reuterin, nisin, lysozyme and sodium nitrite were determined against Clostridium strains in milk and modified RCM (mRCM) after 7d exposure. Although the sensitivity of Clostridium to the tested antimicrobials was strain-dependent, C. sporogenes and C. beijerinckii generally had higher MIC values than the rest of Clostridium species. The majority of Clostridium strains were more resistant to antimicrobials in milk than in mRCM, and vegetative cells exhibited higher sensitivity than spores. Reuterin (MIC values 0.51-32.5 mM) and nisin (MIC values 0.05-12.5 μg/ml) were able to inhibit the growth of vegetative cells and spores of all assayed Clostridium strains in milk and mRCM. Strains of C. tyrobutyricum exhibited the highest sensitivity to lysozyme (MIC valuesClostridium spp. spores and vegetative cells, may be the best options to control Clostridium growth in dairy products and to prevent associated spoilage, such as late blowing defect of cheese. However, further studies in cheese would be necessary to validate this hypothesis.

  15. [Purification and characterization of a lysozyme from a marine microorganism].

    Science.gov (United States)

    Zou, Yan-Li; Sun, Mi; Wang, Yue-Jun

    2005-05-01

    A novel lysozyme was purified from a marine microorganism and its major characteristics were studied. Cell-free supernatant was prepared by centrifugation of culture broth, ultrafiltration using a hollow fiber (molecular weight cut off, 50kD) and concentration using a hollow fiber (molecular weight cut off, 10kD). The crude lysozyme was purified 34.7 fold to electrophoretic homogeneity with a recovery of 24.1% by CM-Sepharose FF cationic-exchange and Sephadex G-100 gel chromatography. The relative molecular weight of this lysozyme was determined as about 39 kD. The optimum pH and temperature towards Micrococcus lysodleikticus were pH 8.0 and 35 degrees C respectively, and the enzyme was stable at temperature below 50 degrees C and pH 5.0 - 10.0. The lysozyme activity was slightly enhanced by Zn2+ and Cu2+ and slightly inhibited by Mn2+ and Ag+. The lysozyme showed good compatibility to many common chemical agents such as EDTA (0.1%) and KH2 PO4 (1.0%). The lysozyme had broad-spectrum against many bacteria, including a number of pathogens, which were resistant to egg-white lysozyme.

  16. ALTERED ENZYMATIC ACTIVITY OF LYSOZYMES BOUND TO VARIOUSLY SULFATED CHITOSANS

    Institute of Scientific and Technical Information of China (English)

    Hong-wei Wang; Lin Yuan; Tie-liang Zhao; He Huang; Hong Chen; Di Wu

    2012-01-01

    The purpose of this research is to investigate the effects of the variously sulfated chitosans on lysozyme activity and structure.It was shown that the specific enzymatic activity of lysozyme remained almost similar to the native protein after being bound to 6-O-sulfated chitosan (6S-chitosan) and 3,6-O-sulfated chitosan (3,6S-chitosan),but decreased greatly after being bound to 2-N-6-O-sulfated chitosan (2,6S-chitosan).Meanwhile,among these sulfated chitosans,2,6S-chitosan induced the greatest conformational change in lysozyme as indicated by the fluorescence spectra.These findings demonstrated that when sulfated chitosans of different structures bind to lysozyme,lysozyme undergoes conformational change of different magnitudes,which results in corresponding levels of lysozyme activity.Further study on the interaction of sulfated chitosans with lysozyme by surface plasmon resonance (SPR) suggested that their affinities might be determined by their molecular structures.

  17. Antimicrobial Pesticides

    Science.gov (United States)

    Jump to main content US EPA United States Environmental Protection Agency Search Search Pesticides Share Facebook Twitter Google+ ... of antimicrobial pesticides (Part 158W) Antimicrobials play an important role in public health and safety. While providing ...

  18. Reentrant condensation of lysozyme: Implications for studying dynamics of lysozyme in aqueous solutions of lithium chloride

    Energy Technology Data Exchange (ETDEWEB)

    Mamontov, Eugene [ORNL; O' Neill, Hugh Michael [ORNL

    2014-01-01

    Recent studies have outlined the use of eutectic solution of lithium chloride in water to study microscopic dynamics of lysozyme in an aqueous solvent that is remarkably similar to pure water in many respects, yet allows experiments over a wide temperature range without the solvent crystallization. The eutectic point in (H2O)R(LiCl) system corresponds to R 7.3, and it is of interest to investigate whether less concentrated aqueous solutions of LiCl could be employed in low-temperature studies of a solvated protein. We have investigated a range of concentrations of lysozyme and LiCl in aqueous solutions to identify systems that do not show phase separation and avoid solvent crystallization on cooling down. Compared to the lysozyme concentration in solution, the concentration of LiCl in the aqueous solvent plays the major role in determining systems suitable for low-temperature studies. We have observed interesting and rich phase behavior reminiscent of reentrant condensation of proteins.

  19. Chitosan films and blends for packaging material.

    Science.gov (United States)

    van den Broek, Lambertus A M; Knoop, Rutger J I; Kappen, Frans H J; Boeriu, Carmen G

    2015-02-13

    An increased interest for hygiene in everyday life as well as in food, feed and medical issues lead to a strong interest in films and blends to prevent the growth and accumulation of harmful bacteria. A growing trend is to use synthetic and natural antimicrobial polymers, to provide non-migratory and non-depleting protection agents for application in films, coatings and packaging. In food packaging, antimicrobial effects add up to the barrier properties of the materials, to increase the shelf life and product quality. Chitosan is a natural bioactive polysaccharide with intrinsic antimicrobial activity and, due to its exceptional physicochemical properties imparted by the polysaccharide backbone, has been recognized as a natural alternative to chemically synthesized antimicrobial polymers. This, associated with the increasing preference for biofunctional materials from renewable resources, resulted in a significant interest on the potential for application of chitosan in packaging materials. In this review we describe the latest developments of chitosan films and blends as packaging material. Copyright © 2014 Elsevier Ltd. All rights reserved.

  20. Molecular cloning, inducible expression and antibacterial analysis of a novel i-type lysozyme (lyz-i2) in Pacific white shrimp, Litopenaeus vannamei.

    Science.gov (United States)

    Chen, Ting; Ren, Chunhua; Wang, Yanhong; Luo, Peng; Jiang, Xiao; Huang, Wen; Chen, Chang; Hu, Chaoqun

    2016-07-01

    The full-length cDNA coding for a novel invertebrate (i-type) lysozyme was identified in Pacific white shrimp (Litopenaeus vannamei). The newly obtained L. vannamei lysozyme is similar to the Penaeus monodon i-type lysozyme 2, but it is distant from the known L. vannamei c-type lysozyme and i-type lysozyme 1 in protein sequence; therefore, it was defined as L. vannamei i-type lysozyme 2 (lyz-i2). Expression of L. vannamei lyz-i2 transcripts were ubiquitously detected in all tissues we selected, with the highest abundance observed in the hemolymph. Challenge with Vibrio harveyi might elicit L. vannamei lyz-i2 mRNA expression in the hepatopancreas, intestine, muscle, gill and hemolymph. In the themolymph, specifically, the stimulatory effects of Vibrio and lipopolysaccharide (LPS) on lyz-i2 transcript levels were durable and transient, respectively; while Polyinosinic:polycytidylic acid [Poly (I:C)] treatment did not affect lyz-i2 expression. L. vannamei lyz-i2 recombinant protein was generated in an Escherichia coli system. By lysoplate and turbidimetric assays, the L. vannamei lyz-i2 recombinant protein showed a broad spectrum of antimicrobial properties with high activities against Micrococcaceae lysodeikticus and various Vibrio species and relatively low activity against E. coli. In conclusion, L. vannamei lyz-i2 might be a potent antibacterial protein with a role in innate immunity in Penaeid shrimp.

  1. Consumption of milk from transgenic goats expressing human lysozyme in the mammary gland results in the modulation of intestinal microflora.

    Science.gov (United States)

    Maga, Elizabeth A; Walker, Richard L; Anderson, Gary B; Murray, James D

    2006-08-01

    Lysozyme is a key antimicrobial component of human milk that has several health-promoting functions including the development of a healthy intestinal tract. However, levels of lysozyme in the milk of dairy animals are negligible. We have generated transgenic dairy goats that express human lysozyme (HLZ) in their milk in an attempt to deliver the benefits of human milk in a continual fashion. To test the feasibility of this transgenic approach to achieve a biological impact at the level of the intestine, feeding trials were conducted in two animal models. Pasteurized milk from HLZ transgenic animals was fed to both kid goats (ruminant model) and young pigs (human model), and the numbers of total coliforms and Escherichia coli present in the small intestine were determined. Data from this proof-of-principle study demonstrate that milk from transgenic animals was capable of modulating the bacterial population of the gut in both animal models. Pigs that consumed pasteurized milk from HLZ transgenic goats had fewer numbers of coliforms and E. coli in their intestine than did those receiving milk from non-transgenic control animals. The opposite effect was seen in goats. Milk from these transgenic animals not only represent one of the first transgenic food products with the potential of benefiting human health, but are also a unique model to study the development and role of intestinal microflora on health, well-being and resistance to disease.

  2. Antimicrobial stewardship.

    Science.gov (United States)

    Allerberger, F; Mittermayer, H

    2008-03-01

    The aim of antimicrobial management or stewardship programmes is to ensure proper use of antimicrobial agents in order to provide the best treatment outcomes, to lessen the risk of adverse effects (including antimicrobial resistance), and to promote cost-effectiveness. Increasingly, long-term sustainability is found to be the major focus of antimicrobial stewardship. Implementing structural measures in healthcare institutions is therefore a major, but not the sole, focus of attention in promoting prudent use of antibiotics. The problem of antimicrobial resistance requires common strategies at all levels--for the prescribers and at ward, departmental, hospital, national and international levels.

  3. Destroying activity of magnetoferritin on lysozyme amyloid fibrils

    Energy Technology Data Exchange (ETDEWEB)

    Kopcansky, Peter; Siposova, Katarina [Institute of Experimental Physics, SAS, Watsonova 47, 040 01 Kosice (Slovakia); Melnikova, Lucia, E-mail: melnikova@saske.sk [Institute of Experimental Physics, SAS, Watsonova 47, 040 01 Kosice (Slovakia); Bednarikova, Zuzana [Institute of Experimental Physics, SAS, Watsonova 47, 040 01 Kosice (Slovakia); Institute of Chemical Sciences, Faculty of Sciences, Safarik University, Kosice (Slovakia); Timko, Milan; Mitroova, Zuzana; Antosova, Andrea [Institute of Experimental Physics, SAS, Watsonova 47, 040 01 Kosice (Slovakia); Garamus, Vasil M. [Helmholtz-Zentrum Geesthacht: Centre for Materials and Coastal Research, Max-Planck-Street 1, 21502 Geesthacht (Germany); Petrenko, Viktor I. [Joint Institute for Nuclear Research, Joliot-Curie 6, Dubna, 141980 Moscow Region (Russian Federation); Kyiv Taras Shevchenko National University, Volodymyrska Street 64, Kyiv 01033 (Ukraine); Avdeev, Mikhail V. [Joint Institute for Nuclear Research, Joliot-Curie 6, Dubna, 141980 Moscow Region (Russian Federation); Gazova, Zuzana [Institute of Experimental Physics, SAS, Watsonova 47, 040 01 Kosice (Slovakia); Department of Medical and Clinical Biochemistry and LABMED, Tr. SNP 1, 040 11 Kosice (Slovakia)

    2015-03-01

    Presence of protein amyloid aggregates (oligomers, protofilaments, fibrils) is associated with many diseases as diabetes mellitus or Alzheimer's disease. The interaction between lysozyme amyloid fibrils and magnetoferritin loaded with different amount of iron atoms (168 or 532 atoms) has been investigated by small-angle X-rays scattering and thioflavin T fluorescence measurements. Results suggest that magnetoferritin caused an iron atom-concentration dependent reduction of lysozyme fibril size. - Highlights: • The interaction between lysozyme amyloid fibrils and magnetoferritin loaded with different amount of iron atoms (168 or 532 atoms) has been investigated by small-angle X-rays scattering and thioflavin T fluorescence measurements. • Results suggest that magnetoferritin caused an iron atom-concentration dependent reduction of lysozyme fibril size.

  4. Structure and stability of complex coacervate core micelles with lysozyme.

    Science.gov (United States)

    Lindhoud, Saskia; Vries, Renko de; Norde, Willem; Stuart, Martien A Cohen

    2007-07-01

    Encapsulation of enzymes by polymers is a promising method to influence their activity and stability. Here, we explore the use of complex coacervate core micelles for encapsulation of enzymes. The core of the micelles consists of negatively charged blocks of the diblock copolymer PAA42PAAm417 and the positively charged homopolymer PDMAEMA150. For encapsulation, part of the positively charged homopolymer was replaced by the positively charged globular protein lysozyme. We have studied the formation, structure, and stability of the resulting micelles for three different mixing ratios of homopolymer and lysozyme: a system predominantly consisting of homopolymer, a system predominantly consisting of lysozyme, and a system where the molar ratio between the two positively charged molecules was almost one. We also studied complexes made of only lysozyme and PAA42PAAm417. Complex formation and the salt-induced disintegration of the complexes were studied using dynamic light-scattering titrations. Small-angle neutron scattering was used to investigate the structures of the cores. We found that micelles predominantly consisting of homopolymer are spherical but that complex coacervate core micelles predominantly consisting of lysozyme are nonspherical. The stability of the micelles containing a larger fraction of lysozyme is lower.

  5. Recombinant goose-type lysozyme in channel catfish: lysozyme activity and efficacy as plasmid DNA immunostimulant against Aeromonas hydrophila infection.

    Science.gov (United States)

    Pridgeon, Julia W; Klesius, Phillip H; Dominowski, Paul J; Yancey, Robert J; Kievit, Michele S

    2013-10-01

    The objectives of this study were: 1) to investigate whether recombinant channel catfish lysozyme-g (CC-Lys-g) produced in Escherichia coli expression system possesses any lysozyme activity; and 2) to evaluate whether channel catfish lysozyme-g plasmid DNA could be used as an immunostimulant to protect channel catfish against Aeromonas hydrophila infection. Recombinant CC-Lys-g produced in E. coli expression system exhibited significant (P recombinant channel catfish lysozyme-g (pcDNA-Lys-g) was transfected in channel catfish gill cells G1B, the over-expression of pcDNA-Lys-g offered significant (P DNA injection. Macrophages of fish injected with pcDNA-Lys-g produced significantly (P DNA injection. Taken together, our results suggest that pcDNA-Lys-g could be used as a novel immunostimulant to offer immediate protection to channel catfish against A. hydrophila infection.

  6. Antimicrobial Activity.

    Science.gov (United States)

    2016-01-01

    Natural products of higher plants may possess a new source of antimicrobial agents with possibly novel mechanisms of action. They are effective in the treatment of infectious diseases while simultaneously mitigating many of the side effects that are often associated with conventional antimicrobials. A method using scanning electron microscope (SEM) to study the morphology of the bacterial and fungal microbes and thus determining antimicrobial activity is presented in the chapter.

  7. Laser ablation of the protein lysozyme

    DEFF Research Database (Denmark)

    Schou, Jørgen; Canulescu, Stela; Amoruso, Salvatore

    Lysozyme is a well-known protein, which is used in food processing because of its bactericidal properties. The mass (14307 amu) is in the range in which it easily can be monitored by mass spectrometric methods, for example by MALDI (Matrix assisted laser desorption ionization). We have recently...... produced thin films of average thickness up to 300 nm, which not only contained a significant amount of intact molecules, but also maintained the bioactivity. These films were produced by a nanosecond laser in the UV regime at 355 nm with 2 J/cm2. The surprising fact that these molecules can be transferred...... to a substrate as intact molecules by the violent laser impact ( up to 50 mJ/pulse) has not yet been understood. One issue is that up to 150 ng/pulse is removed by the laser, and much of the material is ejected from the target in relatively large chunks. We have explored as well the excitation mechanics by laser...

  8. Terahertz absorption of lysozyme in solution

    Science.gov (United States)

    Martin, Daniel R.; Matyushov, Dmitry V.

    2017-08-01

    Absorption of radiation by solution is described by its frequency-dependent dielectric function and can be viewed as a specific application of the dielectric theory of solutions. For ideal solutions, the dielectric boundary-value problem separates the polar response into the polarization of the void in the liquid, created by the solute, and the response of the solute dipole. In the case of a protein as a solute, protein nuclear dynamics do not project on significant fluctuations of the dipole moment in the terahertz domain of frequencies and the protein dipole can be viewed as dynamically frozen. Absorption of radiation then reflects the interfacial polarization. Here we apply an analytical theory and computer simulations to absorption of radiation by an ideal solution of lysozyme. Comparison with the experiment shows that Maxwell electrostatics fails to describe the polarization of the protein-water interface and the "Lorentz void," which does not anticipate polarization of the interface by the external field (no surface charges), better represents the data. An analytical theory for the slope of the solution absorption against the volume fraction of the solute is formulated in terms of the cavity field response function. It is calculated from molecular dynamics simulations in good agreement with the experiment. The protein hydration shell emerges as a separate sub-ensemble, which, collectively, is not described by the standard electrostatics of dielectrics.

  9. Salt-specific effects in lysozyme solutions

    Directory of Open Access Journals (Sweden)

    T. Janc

    2016-03-01

    Full Text Available The effects of additions of low-molecular-mass salts on the properties of aqueous lysozyme solutions are examined by using the cloud-point temperature, T_{cloud}, measurements. Mixtures of protein, buffer, and simple salt in water are studied at pH=6.8 (phosphate buffer and pH=4.6 (acetate buffer. We show that an addition of buffer in the amount above I_{buffer} = 0.6 mol dm^{-3} does not affect the T_{cloud} values. However, by replacing a certain amount of the buffer electrolyte by another salt, keeping the total ionic strength constant, we can significantly change the cloud-point temperature. All the salts de-stabilize the solution and the magnitude of the effect depends on the nature of the salt. Experimental results are analyzed within the framework of the one-component model, which treats the protein-protein interaction as highly directional and of short-range. We use this approach to predict the second virial coefficients, and liquid-liquid phase diagrams under conditions, where T_{cloud} is determined experimentally.

  10. Complex coacervate core micelles with a lysozyme-modified corona.

    Science.gov (United States)

    Danial, Maarten; Klok, Harm-Anton; Norde, Willem; Stuart, Martien A Cohen

    2007-07-17

    This paper describes the preparation, characterization, and enzymatic activity of complex coacervate core micelles (C3Ms) composed of poly(acrylic acid) (PAA) and poly(N-methyl-2-vinyl pyridinium iodide)-b-poly(ethylene oxide) (PQ2VP-PEO) to which the antibacterial enzyme lysozyme is end-attached. C3Ms were prepared by polyelectrolyte complex formation between PAA and mixtures containing different ratios of aldehyde and hydroxyl end-functionalized PQ2VP-PEO. This resulted in the formation of C3Ms containing 0-40% (w/w) of the aldehyde end-functionalized PQ2VP-PEO block copolymer (PQ2VP-PEO-CHO). Chemical conjugation of lysozyme was achieved via reductive amination of the aldehyde groups, which are exposed at the surface of the C3M, with the amine groups present in the side chains of the lysine residues of the protein. Dynamic and static light scattering indicated that the conjugation of lysozyme to C3Ms prepared using 10 and 20% (w/w) PQ2VP-PEO-CHO resulted in the formation of unimicellar particles. Multimicellar aggregates, in contrast, were obtained when lysozyme was conjugated to C3Ms prepared using 30 or 40% (w/w) PQ2VP-PEO-CHO. The enzymatic activity of the unimicellar lysozyme-C3M conjugates toward the hydrolysis of the bacterial substrate Micrococcus lysodeikticus was comparable to that of free lysozyme. For the multimicellar particles, in contrast, significantly reduced enzymatic rates of hydrolysis, altered circular dichroism, and red-shifted tryptophan fluorescence spectra were measured. These results are attributed to the occlusion of lysozyme in the interior of the multimicellar conjugates.

  11. ISOLATION AND PURIFICATION OF LYSOZYME FROM THE HEN EGG WHITE

    Directory of Open Access Journals (Sweden)

    S. S.

    2015-12-01

    Full Text Available The aim of the research was the development of the method of lysozyme isolation from hen egg proteins. Lysozyme was isolated by differential heat denaturation of proteins with changing of the medium pH value, followed by neutralization, dialysis and additional purification by gel chromatography on Sephadex G-50. Activity was determined by bacteriolytic method (with Micrococcus lysodeikticus 4698 as a substrate. The enzyme purity and molecular mass were determined using SDS-electrophoresis and massspectrometry. The method of lysozyme isolation from hen egg proteins with the enzyme yield of 3.2 ± 0.2% and bacteriolytic activity of 22 025 ± 1 500 U/mg is modified. According to electrophoresis data, the isolated enzyme is characterized by high degree of purity (~95–98% and is comparable with lysozyme of AppliChem company by main physical and chemical characteristics. The obtaining product is stored in a crystalline form at low temperature (–24 оC for 9 months. The proposed method allows obtaining active and stable lysozyme with high purity from hen egg protein in laboratory conditions for the usage in biotechnology.

  12. Effects of purification on the crystallization of lysozyme

    Science.gov (United States)

    Ewing, Felecia L.; Forsythe, Elizabeth L.; van der Woerd, Mark; Pusey, Marc L.

    1996-03-01

    We have additionally purified a commercial lysozyme preparation by cation exchange chromatography, followed by recrystallization. This material is 99.96% pure with respect to macromolecular impurities. At basic pH, the purified lysozyme gave only tetragonal crystals at 20°C. Protein used directly from the bottle, prepared by dialysis against distilled water, or which did not bind to the cation exchange column had considerably altered crystallization behavior. Lysozyme which did not bind to the cation exchange column was subsequently purified by size exclusion chromatography. This material gave predominately bundles of rod-shaped crystals with some small tetragonal crystals at lower pHs. The origin of the bundled rod habit was postulated to be a thermally dependent tetragonal ↔ orthorhombic change in the protein structure. This was subsequently ruled out on the basis of crystallization behavior and growth rate experiments. This suggests that heterogeneous forms of lysozyme may be responsible. These results demonstrate three classes of impurities: (1) small molecules, which may be removed by dialysis; (2) macromolecules, which are removable by chromatographic techniques; and (3) heterogeneous forms of the protein, which can be removed in this case by cation exchange chromatography. Of these, heterogeneous forms of the lysozyme apparently have the greatest affect on its crystallization behavior.

  13. Invertebrate lysozymes: Diversity and distribution, molecular mechanism and in vivo function

    Indian Academy of Sciences (India)

    Joris M Van Herreweghe; Chris W Michiels

    2012-06-01

    Lysozymes are antibacterial enzymes widely distributed among organisms. Within the animal kingdom, mainly three major lysozyme types occur. Chicken (c)-type lysozyme and goose (g)-type lysozyme are predominantly, but not exclusively, found in vertebrate animals, while the invertebrate (i)-type lysozyme is typical for invertebrate organisms, and hence its name. Since their discovery in 1975, numerous research articles report on the identification of i-type lysozymes in a variety of invertebrate phyla. This review describes the current knowledge on i-type lysozymes, outlining their distribution, molecular mechanism and in vivo function taking the representative from Venerupis philippinarum (formerly Tapes japonica) (Vp-ilys) as a model. In addition, invertebrate g-type and ch-type (chalaropsis) lysozymes, which have been described in molluscs and nematodes, respectively, are also briefly discussed.

  14. Mechanical, barrier and antimicrobial properties of biodegradable poly(e-caprolactone) nanocomposites

    CSIR Research Space (South Africa)

    Makhado, E

    2015-05-01

    Full Text Available platelets with strong antimicrobial properties and incorporated them into a biodegradable poly(e-caprolactone) (PCL) matrix using the melt-blending technique. Structural analysis of the composites using X-ray diffraction and transmission electron microscopy...

  15. Nanopatterned antimicrobial enzymatic surfaces combining biocidal and fouling release properties

    Science.gov (United States)

    Yu, Qian; Ista, Linnea K.; López, Gabriel P.

    2014-04-01

    Surfaces incorporating the antimicrobial enzyme, lysozyme, have been previously demonstrated to effectively disrupt bacterial cellular envelopes. As with any surface active antimicrobial, however, lysozyme-expressing surfaces become limited in their utility by the accumulation of dead bacteria and debris. Surfaces modified with environmentally responsive polymers, on the other hand, have been shown to reversibly attach and release both live and dead bacterial cells. In this work, we combine the antimicrobial activity of lysozyme with the fouling release capability of the thermally responsive polymer, poly(N-isopropylacrylamide) (PNIPAAm), which has a lower critical solution temperature (LCST) in water at ~32 °C. Nanopatterned PNIPAAm brushes were fabricated using interferometric lithography followed by surface-initiated polymerization. Lysozyme was then adsorbed into the polymer-free regions of the substrate between the brushes to achieve a hybrid surface with switchable antimicrobial activity and fouling-release ability in response to the change of temperature. The temperature triggered hydration and conformational change of the nanopatterned PNIPAAm brushes provide the ability to temporally regulate the spatial concealment and exposure of adsorbed lysozyme. The biocidal efficacy and release properties of the hybrid surface were tested against Escherichia coli K12 and Staphylococcus epidermidis. The hybrid surfaces facilitated the attachment of bacteria at 37 °C for E. coli and 25 °C for S. epidermidis and when the temperature is above the LCST, collapsed and dehydrated PNIPAAm chains expose lysozyme to kill attached bacteria. Changing temperature across the LCST of PNIPAAm (e.g. from 37 °C to 25 °C for E. coli or from 25 °C to 37 °C for S. epidermidis) to induce a hydration transition of PNIPAAm promoted the release of dead bacteria and debris from the surfaces upon mild shearing. These results suggest that nano-engineered surfaces can provide an effective

  16. Purification, amino acid sequence, and some properties of rabbit kidney lysozyme.

    Science.gov (United States)

    Ito, Y; Yamada, H; Nakamura, S; Imoto, T

    1990-02-01

    The lysozyme (rabbit kidney lysozyme) from the homogenate of rabbit kidney (Japanese white) was purified by repeated cation-exchange chromatography on Bio-Rex 70. The amino acid sequence was determined by automated gas-phase Edman degradation of the peptides obtained from the digestion of reduced and S-carboxymethylated rabbit lysozyme with Achromobacter protease I (lysyl endopeptidase). The sequence thus determined was KIYERCELARTLKKLGLDGYKGVSLANWMCLAKWESSYNTRATNYNPGDKSTDYGIFQ INSRYWCNDGKTPRAVNACHIPCSDLLKDDITQAVACAKRVVSDPQGIRAWVAWRNHCQ NQDLTPYIRGCGV, indicating 25 amino acid substitutions from human lysozyme. The lytic activity of rabbit lysozyme against Micrococcus lysodeikticus at pH 7, ionic strength of 0.1, and 30 degrees C was found to be 190 and 60% of those of hen and human lysozymes, respectively. The lytic activity-pH profile of rabbit lysozyme was slightly different from those of hen and human lysozymes. While hen and human lysozymes had wide optimum activities at around pH 5.5-8.5, the optimum activity of rabbit lysozyme was at around pH 5.5-7.0. The high proline content (five residues per molecule compared with two prolines per molecule in hen or human lysozyme) is one of the interesting features of rabbit lysozyme. The transition temperatures for the unfolding of rabbit, human, and hen lysozymes in 3 M guanidine hydrochloride at pH 5.5 were 51.2, 45.5, and 45.4 degrees C, respectively, indicating that rabbit lysozyme is stabler than the other two lysozymes. The high proline content may be responsible for the increased stability of rabbit lysozyme.

  17. A Better Blend

    Science.gov (United States)

    Demski, Jennifer

    2010-01-01

    In May 2009, the US Department of Education released a meta-analysis of effectiveness studies of online, face-to-face, and blended learning models. The analysis found that online learning produced better student outcomes than face-to-face classes, and that blended learning offered an even "larger advantage" over face-to-face. The hybrid approach…

  18. Quaternized Chitosan as an Antimicrobial Agent: Antimicrobial Activity, Mechanism of Action and Biomedical Applications in Orthopedics

    Directory of Open Access Journals (Sweden)

    Ziwei Liu

    2013-01-01

    Full Text Available Chitosan (CS is a linear polysaccharide with good biodegradability, biocompatibility and antimicrobial activity, which makes it potentially useful for biomedical applications, including an antimicrobial agent either alone or blended with other polymers. However, the poor solubility of CS in most solvents at neutral or high pH substantially limits its use. Quaternary ammonium CS, which was prepared by introducing a quaternary ammonium group on a dissociative hydroxyl group or amino group of the CS, exhibited improved water solubility and stronger antibacterial activity relative to CS over an entire range of pH values; thus, this quaternary modification increases the potential biomedical applications of CS in the field of anti-infection. This review discusses the current findings on the antimicrobial properties of quaternized CS synthesized using different methods and the mechanisms of its antimicrobial actions. The potential antimicrobial applications in the orthopedic field and perspectives regarding future studies in this field are also considered.

  19. Blended Learning Design

    DEFF Research Database (Denmark)

    Pedersen, Lise

    2015-01-01

    University College Lillebaelt has decided that 30 percent of all educational elements must be generated as blended learning by the end of the year 2015 as part of a modernization addressing following educational needs: 1. Blended learning can help match the expectations of the future students who...... have grown up in digitized homes and schools. 2. Blended learning helps individualization and differentiation. The students can organize their own learning paths – decide for themselves where and when to study, which paths to follow and in what tempo. 3. Blended learning helps provide resources...... learning. 4. Blended learning can contribute to supporting and improving efficiency of educational efforts. This can for instance be done through programmes for several classes by using video conferencing, allocating traditional face to face teaching to synchronous and asynchronous study activities produce...

  20. Characterization and function of kuruma shrimp lysozyme possessing lytic activity against Vibrio species.

    Science.gov (United States)

    Hikima, Sonomi; Hikima, Jun ichi; Rojtinnakorn, Jiraporn; Hirono, Ikuo; Aoki, Takashi

    2003-10-16

    Lysozyme cDNA was isolated from a kuruma shrimp, Marsupenaeus japonicus, hemocyte cDNA library. The cDNA consists of 1055 base pairs (bp) and encodes a chicken-type (c-type) lysozyme with a deduced amino acid sequence of 156 residues. The kuruma shrimp lysozyme has a high identity (79.7%) with pacific white shrimp lysozyme, and low to moderate identities (33.3-43.0%) with lysozymes of insects and vertebrates. Comparisons with other c-type lysozymes from invertebrates and vertebrates showed that the two catalytic residues (Glu58 and Asp75) and the eight cysteine residue motif were completely conserved. Two novel insertion sequences were also observed in the kuruma and pacific white shrimp lysozyme amino acid sequences. Interestingly, phylogenetic analysis revealed that the kuruma shrimp lysozyme was more closely related to vertebrate c-type lysozymes. Expression of the cDNA in insect cells, using a baculovirus expression system, yielded a recombinant lysozyme with optimum activity at pH 7.5 and 50 degrees C, as evaluated by a lysoplate assay. The kuruma shrimp lysozyme displayed lytic activities against several Vibrio species and fish pathogens, including Vibrio penaeicida (a pathogenic bacteria to the kuruma shrimp) and suggested that shrimp lysozyme affects a greater variety of pathogens.

  1. Dilatometric, refractometric and viscometric study of lysozyme-cation interaction.

    Science.gov (United States)

    Abad, C; Trueba, M; Campos, A; Figueruelo, J E

    1981-11-01

    The interaction between hen egg-white lysozyme and Cu(II) or Co(II) cations has been studied by dilatometry, equilibrium dialysis-differential refractometry and viscometry at different metal cation concentrations. Delta V isotherms in copper and cobalt solutions have been obtained from dilatometry. Preferential adsorption parameters and specific viscosity have been determined from refractometric and viscosimetric measurements. It has been observed that this interaction produces structural alterations in lysozyme. The magnitude of these conformational changes depends on the metal ion and protein concentration. The results obtained using the three techniques are in good agreement.

  2. Differential deposition of antimicrobial proteins in blue tit (Cyanistes caeruleus) clutches by laying order and male attractiveness

    NARCIS (Netherlands)

    D'Alba, Liliana; Shawkey, Matthew D.; Korsten, Peter; Vedder, Oscar; Kingma, Sjouke A.; Komdeur, Jan; Beissinger, Steven R.; Alba, Liliana D’; Graves, J.

    Female birds can influence offspring fitness by varying the relative quantities of egg components they deposit within and between clutches. Antimicrobial proteins (lysozyme, ovotransferrin, and avidin) are significant components of the avian albumen and likely aid in defense of embryos from

  3. Antimicrobial Resistance

    Science.gov (United States)

    ... emergence and spread of antibacterial resistance, including optimal use of antibiotics in both humans and animals. A global action plan on antimicrobial resistance was adopted by Member States at the ...

  4. Refolding of Denatured/Reduced Lysozyme Using Weak-Cation Exchange Chromatography

    Institute of Scientific and Technical Information of China (English)

    Yan WANG; Bo Lin GONG; Xin Du GENG

    2003-01-01

    Oxidative refolding of the denatured/reduced lysozyme was investigated by using weak-cation exchange chromatography (WCX). The stationary phase of WCX binds to the reduced lysozyme and prevented it from forming intermolecular aggregates. At the same time urea and ammonium sulfate were added to the mobile phase to increase the elution strength for lysozyme. Ammonium sulfate can more stabilize the native protein than a common eluting agent, sodium chloride. Refolding of lysozyme by using this WCX is successfully. It was simply carried out to obtain a completely and correctly refolding of the denatured lysozyme at high concentration of 20.0 mg/mL.

  5. Lysozyme Resistance in Streptococcus suis Is Highly Variable and Multifactorial

    NARCIS (Netherlands)

    Wichgers, P.J.; Weeghel, van C.; Rebel, J.M.J.; Smits, M.A.; Putten, van J.P.M.; Smith, H.E.

    2012-01-01

    Background Streptococcus suis is an important infectious agent for pigs and occasionally for humans. The host innate immune system plays a key role in preventing and eliminating S. suis infections. One important constituent of the innate immune system is the protein lysozyme, which is present in a v

  6. Complex coacervate core micelles with a lysozyme-modified corona

    NARCIS (Netherlands)

    Danial, M.; Klok, H.A.; Norde, W.; Cohen Stuart, M.A.

    2007-01-01

    This paper describes the preparation, characterization, and enzymatic activity of complex coacervate core micelles (C3Ms) composed of poly(acrylic acid) (PAA) and poly(N-methyl-2-vinyl pyridinium iodide)-b-poly(ethylene oxide) (PQ2VP-PEO) to which the antibacterial enzyme lysozyme is end-attached.

  7. 21 CFR 862.1490 - Lysozyme (muramidase) test system.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Lysozyme (muramidase) test system. 862.1490 Section 862.1490 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CLINICAL CHEMISTRY AND CLINICAL TOXICOLOGY DEVICES Clinical Chemistry Test...

  8. ASSOCIATION OF LYSOZYME TO PHOSPHOLIPID SURFACES AND VESICLE FUSION

    NARCIS (Netherlands)

    ARNOLD, K; HOEKSTRA, D; OHKI, S

    1992-01-01

    Lysozyme-induced fusion of phosphatidylserine (PS) vesicles was studied as a function of pH. Fusion, monitored by lipid-mixing, was measured by following the dilution of pyrene-labelled phosphatidylcholine, incorporated in PS vesicles, into unlabelled bilayers. It is demonstrated that

  9. Goat milk with and without increased concentrations of lysozyme improves repair of intestinal cell damage induced by enteroaggregative Escherichia coli

    Directory of Open Access Journals (Sweden)

    Carvalho Eunice B

    2012-08-01

    Full Text Available Abstract Background Enteroaggregative Escherichia coli (EAEC causes diarrhea, malnutrition and poor growth in children. Human breast milk decreases disease-causing bacteria by supplying nutrients and antimicrobial factors such as lysozyme. Goat milk with and without human lysozyme (HLZ may improve the repair of intestinal barrier function damage induced by EAEC. This work investigates the effect of the milks on intestinal barrier function repair, bacterial adherence in Caco-2 and HEp-2 cells, intestinal cell proliferation, migration, viability and apoptosis in IEC-6 cells in the absence or presence of EAEC. Methods Rat intestinal epithelial cells (IEC-6, ATCC, Rockville, MD were used for proliferation, migration and viability assays and human colon adenocarcinoma (Caco-2, ATCC, Rockville, MD and human larynx carcinoma (HEp-2, ATCC, Rockville, MD cells were used for bacterial adhesion assays. Goats expressing HLZ in their milk were generated and express HLZ in milk at concentration of 270 μg/ml . Cells were incubated with pasteurized milk from either transgenic goats expressing HLZ or non-transgenic control goats in the presence and absence of EAEC strain 042 (O44:H18. Results Cellular proliferation was significantly greater in the presence of both HLZ transgenic and control goat milk compared to cells with no milk. Cellular migration was significantly decreased in the presence of EAEC alone but was restored in the presence of milk. Milk from HLZ transgenic goats had significantly more migration compared to control milk. Both milks significantly reduced EAEC adhesion to Caco-2 cells and transgenic milk resulted in less colonization than control milk using a HEp-2 assay. Both milks had significantly increased cellular viability as well as less apoptosis in both the absence and presence of EAEC. Conclusions These data demonstrated that goat milk is able to repair intestinal barrier function damage induced by EAEC and that goat milk with a higher

  10. Use of Lysozyme as a Feed Additive on Rumen Fermentation and Methane Emission

    Directory of Open Access Journals (Sweden)

    Ashraf A. Biswas

    2016-11-01

    Full Text Available This study was conducted to determine the effect of lysozyme addition on in vitro rumen fermentation and to identify the lysozyme inclusion rate for abating methane (CH4 production. An in vitro ruminal fermentation technique was done using a commercial concentrate to rice straw ratio of 8:2 as substrate. The following treatments were applied wherein lysozyme was added into 1 mg dry matter substrate at different levels of inclusion: Without lysozyme, 2,000, 4,000, and 8,000 U lysozyme. Results revealed that, lysozyme addition had a significant effect on pH after 24 h of incubation, with the highest pH (p<0.01 observed in 8,000 U lysozyme, followed by the 4,000 U, 2,000 U, and without lysozyme. The highest amounts of acetic acid, propionic acid (p<0.01 and total volatile fatty acid (TVFA (p<0.05 were found in 8,000 U after 24 h of incubation. The CH4 concentration was the lowest in the 8,000 U and the highest in the without lysozyme addition after 24 h of incubation. There was no significant differences in general bacteria, methanogen, or protozoan DNA copy number. So far, addition of lysozyme increased the acetate, propionate, TVFA, and decreased CH4 concentration. These results suggest that lysozyme supplementation may improve in vitro rumen fermentation and reduce CH4 emission.

  11. Impact of lysozyme on stability mechanism of nanozirconia aqueous suspension

    Energy Technology Data Exchange (ETDEWEB)

    Szewczuk-Karpisz, Katarzyna, E-mail: k.szewczuk-karpisz@wp.pl; Wiśniewska, Małgorzata

    2016-08-30

    Highlights: • Adsorption and stabilization-destabilization properties of lysozyme (LSZ) in the nanozirconia-biopolymer solution system were determined. • The stability measurements were performed using turbidimetric method. • Lysozyme macromolecules undergo adsorption on the ZrO{sub 2} surface under electrostatic adsorbent-adsorbate attraction, i.e. at pH 6 and 9. • The biopolymer adsorption impact on the zirconia stability varies at different pH values. - Abstract: The effect of lysozyme (LSZ) presence on the zirconium(IV) oxide (ZrO{sub 2}) aqueous suspension stability was examined. The applied zirconia contains mesopores (with a diameter about 30 nm) and its mean particle size is about 100 nm. To determine the stability mechanism of ZrO{sub 2} suspension in the biopolymer presence, the adsorption and electrokinetic (surface charge density and zeta potential) measurements were performed in the pH range 3–10. The lysozyme adsorption on the nanozirconia surface proceeds mainly through electrostatic forces. Under solid-polymer repulsion conditions, there is no adsorption of lysozyme (pH < 6, C{sub NaCl} 0.01 mol/dm{sup 3}). The increase of solution ionic strength to 0.2 mol/dm{sup 3} causes screening of unfavourable forces and biopolymer adsorption becomes possible. The LSZ addition to the ZrO{sub 2} suspension influences its stability. At pH 3, 4.6 and 7.6, slight improvement of the system stability was obtained. In turn, at pH 9 considerable destabilization of nanozirconia particles covered by polymeric layers occurs.

  12. MOOC Blended learning ontwikkelen

    NARCIS (Netherlands)

    Verjans, Steven

    2015-01-01

    Presentatie over het ontwerpen van leeractiviteiten (learning design) tijdens de zesde live sessie van de MOOC Blended learning ontwikkelen. Met gebruikmaking van presentatiematerialen van Diana Laurillard, Grainne Conole, Helen Beetham, Jos Fransen, Pieter Swager, Helen Keegan, Corinne Weisgerber.

  13. MOOC Blended learning ontwikkelen

    NARCIS (Netherlands)

    Verjans, Steven

    2015-01-01

    Presentatie over het ontwerpen van leeractiviteiten (learning design) tijdens de zesde live sessie van de MOOC Blended learning ontwikkelen. Met gebruikmaking van presentatiematerialen van Diana Laurillard, Grainne Conole, Helen Beetham, Jos Fransen, Pieter Swager, Helen Keegan, Corinne Weisgerber.

  14. Chicken-type lysozyme in channel catfish: Expression analysis, lysozyme activity and efficacy as immunostimulant against Aeromonas hydrophila infection

    Science.gov (United States)

    To understand whether chicken-type lysozyme (Lys-c) in channel catfish was induced by infection of Aeromonas hydrophila, the transcriptional levels of Lys-c in skin, gut, liver, spleen, posterior kidney, and blood cells in healthy channel catfish was compared to that in channel catfish infected with...

  15. Antimicrobial edible films and coatings.

    Science.gov (United States)

    Cagri, Arzu; Ustunol, Zeynep; Ryser, Elliot T

    2004-04-01

    Increasing consumer demand for microbiologically safer foods, greater convenience, smaller packages, and longer product shelf life is forcing the industry to develop new food-processing, cooking, handling, and packaging strategies. Nonfluid ready-to-eat foods are frequently exposed to postprocess surface contamination, leading to a reduction in shelf life. The food industry has at its disposal a wide range of nonedible polypropylene- and polyethylene-based packaging materials and various biodegradable protein- and polysaccharide-based edible films that can potentially serve as packaging materials. Research on the use of edible films as packaging materials continues because of the potential for these films to enhance food quality, food safety, and product shelf life. Besides acting as a barrier against mass diffusion (moisture, gases, and volatiles), edible films can serve as carriers for a wide range of food additives, including flavoring agents, antioxidants, vitamins, and colorants. When antimicrobial agents such as benzoic acid, sorbic acid, propionic acid, lactic acid, nisin, and lysozyme have been incorporated into edible films, such films retarded surface growth of bacteria, yeasts, and molds on a wide range of products, including meats and cheeses. Various antimicrobial edible films have been developed to minimize growth of spoilage and pathogenic microorganisms, including Listeria monocytogenes, which may contaminate the surface of cooked ready-to-eat foods after processing. Here, we review the various types of protein-based (wheat gluten, collagen, corn zein, soy, casein, and whey protein), polysaccharide-based (cellulose, chitosan, alginate, starch, pectin, and dextrin), and lipid-based (waxes, acylglycerols, and fatty acids) edible films and a wide range of antimicrobial agents that have been or could potentially be incorporated into such films during manufacture to enhance the safety and shelf life of ready-to-eat foods.

  16. 凡纳对虾溶菌酶基因的克隆与性质研究%Gene Cloning and Characterization of Lysozyme Gene in Litopenaeus vannamei

    Institute of Scientific and Technical Information of China (English)

    杜志强; 王建英

    2013-01-01

      凡纳对虾先天免疫系统中的抗菌肽效应分子是发挥抗菌作用的关键分子,其中,溶菌酶分子在对抗细菌的侵染过程中,发挥着重要的清除细菌的作用。以凡纳对虾溶菌酶基因作为研究对象,通过进行基因克隆、氨基酸序列比对、系统进化关系分析以及分子结构的初步预测,推测该溶菌酶基因在凡纳对虾先天免疫系统中发挥着重要的抗菌作用。%  Antimicrobial peptide effectors played the key and important antibacterial role in the Litopenaeus vannamei innate immunity system. And the lysozyme also played an important part in the clearance of bacteria during the bacteria infection process. In this paper , Litopenaeus vannamei lysozyme gene was the research object. And the gene cloning, the amino acids sequence alignment, the phylogenetic relationship analysis, and the preliminary forecasts for molecular structure were done. We speculated that the lysozyme gene played an important part in the antibacterial function in the Litopenaeus vannamei innate immunity system.

  17. Conductivity and Viscosity Measurements for Binary Lysozyme Chloride Aqueous Solution and Ternary Lysozyme-Salt-Water Solution

    CERN Document Server

    Buzatu, D; Buzatu, F D

    2004-01-01

    We use the conductimetric method, adequate to electrolytes, to determine the lysozyme charge in lys-water and ternary lys-salt-water systems. We measured also the viscosities for the above binary and ternary systems in the same conditions at pH$=4.5$ and T$=298$ K, measurements that allow us to see any effect of viscosity on cations mobilities and implicitly on the lysozyme charge. The method is illustrated for the lysozyme chloride aqueous solution system at 25$^o$ C, using the data reported here for pH$=4.5$ at 0.15, 0.6, 0.8, 1., 1.5, 2., 2.5, 3., 3.5 mM (mg/mL) lysozyme chloride concentrations. The method was also applied to ternary lys-salt-water systems in the same conditions at pH$=4.5$ and T$=25^o$ C. Ternary conductivities are reported for a mean concentration 0.6 mM of lysozyme chloride in all systems and a mean concentration 0.01, 0.025, 0.05, 0.1, 0.175, 0.2, 0.5, 0.7, 0.9, 1.2, 1.3 and 1.4 M for NaCl; 0.005, 0.01, 0.05, 0.1, 0.175, 0.2, 0.5, 0.7, 0.9, 1.2, 1.3, 1.4 and 1.5 M for KCl; 0.005, 0.01,...

  18. Human lysozyme peptidase resistance is perturbed by the anionic glycolipid biosurfactant rhamnolipid produced by the opportunistic pathogen Pseudomonas aeruginosa

    DEFF Research Database (Denmark)

    Andersen, Kell K; Vad, Brian Stougaard; Scavenius, Carsten;

    2016-01-01

    Infection by the opportunistic pathogen Pseudomonas aeruginosa (PA) is accompanied by the secretion of virulence factors such as the secondary metabolite rhamnolipid (RL) as well as an array of bacterial enzymes, including the protease elastase. The human immune system tries to counter this via...... defensive proteins such as human lysozyme (HLZ). HLZ targets the bacterial cell wall but may also have other antimicrobial activities. The enzyme contains four disulfide bonds and shows high thermodynamic stability and resistance to proteolytic attack. Here we show that RL promotes HLZ degradation...... by several unrelated proteases, including the PA elastase and human proteases. This occurs although RL does not by itself denature HLZ. Nevertheless, RL binds in a sufficiently high stoichiometry (8 RL:1 HLZ) to neutralize the highly cationic surface of HLZ. The initial cleavage sites agree well...

  19. Non-covalent conjugation of CdTe QDs with lysozyme binding DNA for fluorescent sensing of lysozyme in complex biological sample.

    Science.gov (United States)

    Li, Shujia; Gao, Zhidan; Shao, Na

    2014-11-01

    Water-soluble cysteamine (CA) capped CdTe quantum dots (QDs) conjugated with lysozyme binding DNA (LBD) was constructed for luminescent sensing of lysozyme by forming a ternary self-assembly complex. Addition of negatively charged lysozyme binding DNA to the positively charged CA capped CdTe QDs buffer solution (Tris-HCl pH 7.4) could lead to the formation of QDs-LBD complex through electrostatic interactions. Once lysozyme was introduced into the CdTe QDs-LBD system, it could bind specifically with the QDs-LBD complex, resulting in fluorescence emission enhancement of the QDs due to the surface inert of QDs. At a given amount of LBD and CdTe QDs (LBD: QDs=2: 1), the fluorescence intensity enhancement of QDs was linear with lysozyme concentration over the range of 8.9-71.2 nM, with a detection limit of 4.3 nM. Due to the specific binding of LBD with lysozyme, this approach displayed high selectivity for lysozyme recognition. The sensing mechanism was confirmed by DLS and zeta potential measurement, and agarose gel electrophoresis experiment. Furthermore, the proposed CA-capped CdTe QDs-LBD sensor was applied to lysozyme detection in mouse serum and human morning urine samples, which showed high sensitivity and selectivity in the complex biological sample.

  20. Antimicrobial polymers.

    Science.gov (United States)

    Jain, Anjali; Duvvuri, L Sailaja; Farah, Shady; Beyth, Nurit; Domb, Abraham J; Khan, Wahid

    2014-12-01

    Better health is basic requirement of human being, but the rapid growth of harmful pathogens and their serious health effects pose a significant challenge to modern science. Infections by pathogenic microorganisms are of great concern in many fields such as medical devices, drugs, hospital surfaces/furniture, dental restoration, surgery equipment, health care products, and hygienic applications (e.g., water purification systems, textiles, food packaging and storage, major or domestic appliances etc.) Antimicrobial polymers are the materials having the capability to kill/inhibit the growth of microbes on their surface or surrounding environment. Recently, they gained considerable interest for both academic research and industry and were found to be better than their small molecular counterparts in terms of enhanced efficacy, reduced toxicity, minimized environmental problems, resistance, and prolonged lifetime. Hence, efforts have focused on the development of antimicrobial polymers with all desired characters for optimum activity. In this Review, an overview of different antimicrobial polymers, their mechanism of action, factors affecting antimicrobial activity, and application in various fields are given. Recent advances and the current clinical status of these polymers are also discussed.

  1. Human lysozyme expressed in the mammary gland of transgenic dairy goats can inhibit the growth of bacteria that cause mastitis and the cold-spoilage of milk.

    Science.gov (United States)

    Maga, Elizabeth A; Cullor, James S; Smith, Wayne; Anderson, Gary B; Murray, James D

    2006-01-01

    The addition of human milk components with intrinsic antimicrobial activity to livestock milk by genetic engineering has the potential to benefit milk safety and production as well as the health of the lactating animal. As a model for the dairy cow, we generated transgenic goats that expressed human lysozyme in their milk at 68% of the levels found in human milk. Milk from these transgenic animals had a bacteriostatic effect on both in vitro and in vivo growth of several microorganisms important to the dairy industry. In vitro, milk from transgenic animals was capable of slowing the growth of mastitis-causing strains of Escherichia coli (P transgenic animals. In vivo, milk from transgenic animals supported less bacterial growth than control milk. This transgenic model demonstrates the possibilities offered by genetic engineering to enhance the antimicrobial nature of milk and the udder.

  2. Laser ablation dynamics and production of thin films of lysozyme

    DEFF Research Database (Denmark)

    Schou, Jørgen; Canulescu, Stela; Matei, Andreea;

    at the Technical University of Denmark (DTU) produced thin films of average thickness up to 300 nm, which not only contained a significant amount of intact molecules, but also maintained the bioactivity. These films were produced by a nanosecond laser in the UV regime at 355 nm with 2 J/cm2. The surprising fact......, there was a considerable ablation weight loss of lysozyme from each shot. This is the first time the ablation by fs-lasers of a protein has been recorded quantitatively. Films of lysozyme produced by fs-laser irradiation will be analysed by MALDI in order to explore if there also is a significant amount of intact...... molecules in the films for fs-laser deposition....

  3. Chitosan and Cystatin/Lysozyme Preparation as Protective Edible Films Components

    Directory of Open Access Journals (Sweden)

    Anna Zimoch-Korzycka

    2015-01-01

    Full Text Available This work characterizes biological, physical, and chemical properties of films formed from an aqueous solution of hydroxypropyl methylcellulose (HPMC, with different concentrations of chitosan (CH and bioactive cystatin/lysozyme preparation (C/L. The properties of biocomposites were examined by Dynamic Mechanical Analysis (DMA, Fourier’s transfer infrared spectroscopy (FTIR, water vapour permeability (WVP, and tensile testing. Antimicrobial activity against Micrococcus flavus, Bacillus cereus, Escherichia coli, Pseudomonas fluorescens, and Candida famata was conducted. Films glass transition and storage modulus were dependent on the C/L and CH concentration. Modulus values decreased during the temperature scan and with higher reagents levels. An increase of CH and C/L concentrations in the films resulted in a decrease in tensile strength from 2.62 to 1.08 MPa. It suggests the hydrolyzing influence of C/L, also observed in smaller peak size of α relaxation. C/L addition caused shifting Tg to higher temperature. DMA and FTIR analysis proved that HPMC and CH are compatible polymers. Water resistance was improved with rising CH concentration from 1.08E-09 to 7.71E−10 g/m∗s∗Pa. The highest inhibition zone in M. flavus and C. famata was recorded at the highest concentration of CH and C/L.

  4. Lysozyme coated DNA and DNA/SWNT fibers by solution spinning.

    Science.gov (United States)

    Nepal, Dhriti; Minus, Marilyn L; Kumar, Satish

    2011-07-07

    DNA fibers were prepared by solution spinning of DNA in a lysozyme (LSZ) coagulation/gelation bath. Strong positive charges carried by LSZ protein condensed the DNA (strong negative charged) molecules resulting in self-assembly and the formation of fibrillar structures in a gel-like network. DNA/LSZ fibril formation was found to be dependent on the ratio of DNA to LSZ. A minimum 0.1 wt.-% of LSZ was necessary to condense 0.1 wt.-% of DNA into micro-fibrils. Macroscopic fiber spinning was possible by introducing a 0.1 wt.-% DNA aqueous solution into a 0.2 wt.-% LSZ coagulation bath which resulted in fibers with ≈20 µm diameter. Single-walled carbon nanotubes (SWNT) were also incorporated into these fibers to explore the possibility for creating hybrid materials. All DNA-based fibers exhibit strong birefringence confirming molecular orientation along the fiber axis. Due to the presence of LSZ, the fibers exhibit antimicrobial activity against bacteria like Micrococcus lysodeikticus.

  5. Blended Learning Environments and Suggesstions for Blended Learning Design

    Directory of Open Access Journals (Sweden)

    Funda DAĞ

    2011-06-01

    Full Text Available The number of studies in blended learning field, which has gained importance by being reinterpreted with the effect of the developments in information and communication technologies, has been increasing recently. There have been many diverse approaches in these studies on the point of defining blended learning and on the point of which components of blended learning environments need blending and how they are blended. The aim of this study is to examine national and international studies in blended learning in higher education and to make suggestions about necessary components for designing an effective blended learning environment. Within this framework the studies on blended learning, which were accessible online, were examined from the perspectives of research methods that were used, preferred e-learning environments and/or e-learning methods, preferred face to face learning/teaching strategies and the methods used in the evaluation of blended learning. In the light of the findings it is seen that blended learning should be regarded as a teaching design approach in order to create effectively blended learning environments and it is hoped that the suggestions made will be lodestar in forming blended learning models for diverse learning fields.

  6. Supporting School Leaders in Blended Learning with Blended Learning

    Science.gov (United States)

    Acree, Lauren; Gibson, Theresa; Mangum, Nancy; Wolf, Mary Ann; Kellogg, Shaun; Branon, Suzanne

    2017-01-01

    This study provides a mixed-methods case-study design evaluation of the Leadership in Blended Learning (LBL) program. The LBL program uses blended approaches, including face-to-face and online, to prepare school leaders to implement blended learning initiatives in their schools. This evaluation found that the program designers effectively…

  7. Relationship Between Equilibrium Forms of Lysozyme Crystals and Precipitant Anions

    Science.gov (United States)

    Nadarajah, Arunan

    1996-01-01

    Molecular forces, such as electrostatic, hydrophobic, van der Waals and steric forces, are known to be important in determining protein interactions. These forces are affected by the solution conditions and changing the pH, temperature or the ionic strength of the solution can sharply affect protein interactions. Several investigations of protein crystallization have shown that this process is also strongly dependent on solution conditions. As the ionic strength of the solution is increased, the initially soluble protein may either crystallize or form an amorphous precipitate at high ionic strengths. Studies done on the model protein hen egg white lysozyme have shown that different crystal forms can be easily and reproducibly obtained, depending primarily on the anion used to desolubilize the protein. In this study we employ pyranine to probe the effect of various anions on the water structure. Additionally, lysozyme crystallization was carried out at these conditions and the crystal form was determined by X-ray crystallography. The goal of the study was to understand the physico-chemical basis for the effect of changing the anion concentration on the equilibrium form of lysozyme crystals. It will also verify the hypothesis that the anions, by altering the bulk water structure in the crystallizing solutions, alter the surface energy of the between the crystal faces and the solution and, consequently, the equilibrium form of the crystals.

  8. Comparative insight into surfactants mediated amyloidogenesis of lysozyme.

    Science.gov (United States)

    Chaturvedi, Sumit K; Khan, Javed M; Siddiqi, Mohammad K; Alam, Parvez; Khan, Rizwan H

    2016-02-01

    Electrostatic and hydrophobic interactions have an important role in the protein aggregation. In this study, we have investigated the effect of charge and hydrophobicity of oppositely charged surfactants i.e., anionic (AOT and SDS) and cationic (CTAB and DTAB) on hen egg white lysozyme at pH 9.0 and 13.0, respectively. We have employed various methods such as turbidity measurements, Rayleigh light scattering, ThT, Congo red and ANS dye binding assays, far-UV CD, atomic force microscopy, transmission electron and fluorescence microscopy. At lower molar ratio, both anionic and cationic surfactants promote amyloid fibril formation in lysozyme at pH 9.0 and 13.0, respectively. The aggregation was proportionally increased with respect to protein concentration and hydrophobicity of surfactant. The morphology of aggregates at both the pH was fibrillar in structure, as visualized by dye binding and microscopic imaging techniques. Initially, the interaction between surfactants and lysozyme was electrostatic and then hydrophobic as investigated by ITC. This study demonstrates the crucial role of charge and hydrophobicity during amyloid fibril formation.

  9. On the adsorption of magnetite nanoparticles on lysozyme amyloid fibrils.

    Science.gov (United States)

    Majorosova, Jozefina; Petrenko, Viktor I; Siposova, Katarina; Timko, Milan; Tomasovicova, Natalia; Garamus, Vasil M; Koralewski, Marceli; Avdeev, Mikhail V; Leszczynski, Błażej; Jurga, Stefan; Gazova, Zuzana; Hayryan, Shura; Hu, Chin-Kun; Kopcansky, Peter

    2016-10-01

    An adsorption of magnetic nanoparticles (MNP) from electrostatically stabilized aqueous ferrofluids on amyloid fibrils of hen egg white lysozyme (HEWL) in 2mg/mL acidic dispersions have been detected for the MNP concentration range of 0.01-0.1vol.%. The association of the MNP with amyloid fibrils has been characterized by transmission electron microscopy (TEM), small-angle X-ray scattering (SAXS) and magneto-optical measurements. It has been observed that the extent of adsorption is determined by the MNP concentration. When increasing the MNP concentration the formed aggregates of magnetic particles repeat the general rod-like structure of the fibrils. The effect is not observed when MNP are mixed with the solution of lysozyme monomers. The adsorption has been investigated with the aim to clarify previously found disaggregation activity of MNP in amyloid fibrils dispersions and to get deeper insight into interaction processes between amyloids and MNP. The observed effect is also discussed with respect to potential applications for ordering lysozyme amyloid fibrils in a liquid crystal phase under external magnetic fields.

  10. Aggregation of silica nanoparticles directed by adsorption of lysozyme.

    Science.gov (United States)

    Bharti, Bhuvnesh; Meissner, Jens; Findenegg, Gerhard H

    2011-08-16

    The interaction of the globular protein lysozyme with silica nanoparticles of diameter 20 nm was studied in a pH range between the isoelectric points (IEPs) of silica and the protein (pH 3-11). The adsorption affinity and capacity of lysozyme on the silica particles is increasing progressively with pH, and the adsorbed protein induces bridging aggregation of the silica particles. Structural properties of the aggregates were studied as a function of pH at a fixed protein-to-silica concentration ratio which corresponds to a surface concentration of protein well below a complete monolayer in the complete-binding regime at pH > 6. Sedimentation studies indicate the presence of compact aggregates at pH 4-6 and a loose flocculated network at pH 7-9, followed by a sharp decrease of aggregate size near the IEP of lysozyme. The structure of the bridged silica aggregates was studied by cryo-transmission electron microscopy (cryo-TEM) and small-angle X-ray scattering. The structure factor S(q) derived from the scattering profiles displays characteristic features of particles interacting by a short-range attractive potential and can be represented by the square-well Percus-Yevick potential model, with a potential depth not exceeding 3k(B)T.

  11. AKRO/SF: Blend System

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Blend was the system used by the NMFS Alaska Regional Office to monitor groundfish catch from 1991 until 2002. The Blend system combined data from industry...

  12. Polymer Blends. Volume 1

    Science.gov (United States)

    1992-05-01

    PBI/ ULTEM NEAT RESIN MOLDING EVALUATIONS 18 2.1.3 85/15 PBI/ ULTEM COMPOSITE EVALUATIONS 22 2.1.4 FIRST GENERATION SUMMARY 26 2.2 IMPROVED PBI/"BEST...PBI 37 2.2.4 85/15 eCPBI-2/ ULTEM NEAT RESIN EVALUATIONS 42 2.2.5 SECOND GENERATION SUMMARY 45 2.3 IMPROVED PBI/6F POLYIMIDE BLENDS: THIRD GENERATION...PYROMELLITIC DIANHYDRIDE 100 A1.2 REVIEW AND RISK ANALYSIS 105 iv FIGURES FIGURE PAGE # I HIGH PERFORMANCE POLYMER BLENDS PLAN 6 2 PBI/ ULTEM SEPARATION

  13. Synergistic actions of complement and lysozyme in clearance of Escherichia coli from amphioxus Branchiostoma belcheri

    Institute of Scientific and Technical Information of China (English)

    Guangfeng Wang; Shicui Zhang; Zhimeng Zhuang; Zhiping Wang

    2009-01-01

    Amphioxus appears to lack free circulating blood cells. How it clears invading pathogens from its body remains unknown to date. We demonstrate here that amphioxus Branchiostoma belcheri is capable of efficiently eliminating the invading bacterium Escherichia coil from its humorai fluid, and the complement and lysozyme are both involved in the elimination of the invading pathogen. Both the com-plement and lysozyme act in concert against the invading bacterium, but the complement appears to play a more dominant role than the lysozyme.

  14. Protective properties of lysozyme on β-amyloid pathology: implications for Alzheimer disease.

    Science.gov (United States)

    Helmfors, Linda; Boman, Andrea; Civitelli, Livia; Nath, Sangeeta; Sandin, Linnea; Janefjord, Camilla; McCann, Heather; Zetterberg, Henrik; Blennow, Kaj; Halliday, Glenda; Brorsson, Ann-Christin; Kågedal, Katarina

    2015-11-01

    The hallmarks of Alzheimer disease are amyloid-β plaques and neurofibrillary tangles accompanied by signs of neuroinflammation. Lysozyme is a major player in the innate immune system and has recently been shown to prevent the aggregation of amyloid-β1-40 in vitro. In this study we found that patients with Alzheimer disease have increased lysozyme levels in the cerebrospinal fluid and lysozyme co-localized with amyloid-β in plaques. In Drosophila neuronal co-expression of lysozyme and amyloid-β1-42 reduced the formation of soluble and insoluble amyloid-β species, prolonged survival and improved the activity of amyloid-β1-42 transgenic flies. This suggests that lysozyme levels rise in Alzheimer disease as a compensatory response to amyloid-β increases and aggregation. In support of this, in vitro aggregation assays revealed that lysozyme associates with amyloid-β1-42 and alters its aggregation pathway to counteract the formation of toxic amyloid-β species. Overall, these studies establish a protective role for lysozyme against amyloid-β associated toxicities and identify increased lysozyme in patients with Alzheimer disease. Therefore, lysozyme has potential as a new biomarker as well as a therapeutic target for Alzheimer disease. Copyright © 2015. Published by Elsevier Inc.

  15. The interaction of lysozyme with caffeine, theophylline and theobromine in solution.

    Science.gov (United States)

    Zhang, Hong-Mei; Tang, Bo-Ping; Wang, Yan-Qing

    2010-10-01

    The interactions of lysozyme with caffeine (Caf), theophylline (Tph) and theobromine (Tbr) were investigated using UV-Vis absorption, fluorescence, synchronous fluorescence, and three-dimensional fluorescence spectra techniques. The results revealed that Caf (Tph or Tbr) caused the fluorescence quenching of lysozyme by the formation of Caf (Tph or Tbr)-lysozyme complex. The binding constants (K(A)) and thermodynamic parameters (ΔG°, ΔH°, ΔS°) at two different temperatures, the binding locality, and the binding power were obtained. The results showed that the process of binding Caf (Tph or Tbr) to lysozyme was a spontaneous molecular interaction procedure and the hydrophobic and electrostatic interactions play a major role in stabilizing the complex; The distance r between donor (lysozyme) and acceptor (Caf, Tph or Tbr) was obtained according to fluorescence resonance energy transfer. The effect of Caf (Tph or Tbr) on the conformation of lysozyme was analyzed using synchronous fluorescence and three-dimensional fluorescence spectra techniques. The results showed that the binding of Caf (Tph or Tbr) to lysozyme induced some micro-environmental and conformational changes in lysozyme and disturbed the environment of the polypeptide of lysozyme.

  16. Pulsed laser deposition of lysozyme: the dependence on shot numbers and the angular distribution

    DEFF Research Database (Denmark)

    Constantinescu, C.; Matei, A.; Schou, Jørgen

    2013-01-01

    . This was verified by matrix-assisted laser desorption ionization (MALDI) spectrometry of thin films deposited on silicon substrates. The deposition rate of lysozyme was found to decrease with the number of shots and was correlated with increasing thermal damage of the lysozyme. This was monitored by measurements...... of the optical reflectivity of dry lysozyme. The angular distribution of the mass deposition can be fitted well by Anisimov’s hydrodynamic model. The total deposited yield over the entire hemisphere from direct laser ablation of lysozyme was estimated from this model and found to be three orders of magnitude...

  17. Expression of lysozymes from Erwinia amylovora phages and Erwinia genomes and inhibition by a bacterial protein.

    Science.gov (United States)

    Müller, Ina; Gernold, Marina; Schneider, Bernd; Geider, Klaus

    2012-01-01

    Genes coding for lysozyme-inhibiting proteins (Ivy) were cloned from the chromosomes of the plant pathogens Erwinia amylovora and Erwinia pyrifoliae. The product interfered not only with activity of hen egg white lysozyme, but also with an enzyme from E. amylovora phage ΦEa1h. We have expressed lysozyme genes from the genomes of three Erwinia species in Escherichia coli. The lysozymes expressed from genes of the E. amylovora phages ΦEa104 and ΦEa116, Erwinia chromosomes and Arabidopsis thaliana were not affected by Ivy. The enzyme from bacteriophage ΦEa1h was fused at the N- or C-terminus to other peptides. Compared to the intact lysozyme, a His-tag reduced its lytic activity about 10-fold and larger fusion proteins abolished activity completely. Specific protease cleavage restored lysozyme activity of a GST-fusion. The bacteriophage-encoded lysozymes were more active than the enzymes from bacterial chromosomes. Viral lyz genes were inserted into a broad-host range vector, and transfer to E. amylovora inhibited cell growth. Inserted in the yeast Pichia pastoris, the ΦEa1h-lysozyme was secreted and also inhibited by Ivy. Here we describe expression of unrelated cloned 'silent' lyz genes from Erwinia chromosomes and a novel interference of bacterial Ivy proteins with a viral lysozyme.

  18. Lysozyme-immobilized electrospun PAMA/PVA and PSSA-MA/PVA ion-exchange nanofiber for wound healing.

    Science.gov (United States)

    Tonglairoum, Prasopchai; Ngawhirunpat, Tanasait; Rojanarata, Theerasak; Opanasopit, Praneet

    2014-08-27

    Abstract This research was aimed to develop the lysozyme immobilized ion-exchange nanofiber mats for wound healing. To promote the healing process, the PSSA-MA/PVA and PAMA ion-exchange nanofiber mats were fabricated to mimic the extracellular matrix structure using electrospinning process followed by thermally crosslinked. Lysozyme was immobilized on the ion-exchane nanofibers by an adsorption method. The ion-exchange nanofibers were investigated using SEM, FTIR and XRPD. Moreover, the lysozyme-immobilized ion-exchange nanofibers were further investigated for lysozyme content and activity, lysozyme release and wound healing activity. The fiber diameters of the mats were in the nanometer range. Lysozyme was gradually absorbed into the PSSA-MA/PVA nanofiber with higher extend than that is absorbed on the PAMA/PVA nanofiber and exhibited higher activity than lysozyme-immobilized PAMA/PVA nanofiber. The total contents of lysozyme on the PSSA-MA/PVA and PAMA/PVA nanofiber were 648 and 166 µg/g, respectively. FTIR and lysozyme activity results confirmed the presence of lysozyme on the nanofiber mats. The lysozyme was released from the PSSA-MA/PVA and PAMA/PVA nanofiber in the same manner. The lysozyme-immobilized PSSA-MA/PVA nanofiber mats and lysozyme-immobilized PAMA/PVA nanofiber mats exhibited significantly faster healing rate than gauze and similar to the commercial antibacterial gauze dressing. These results suggest that these nanofiber mats could provide the promising candidate for wound healing application.

  19. Animation of Antimicrobial Resistance

    Science.gov (United States)

    ... Veterinary Safety & Health Antimicrobial Resistance Animation of Antimicrobial Resistance Share Tweet Linkedin Pin it More sharing options ... produced a nine-minute animation explaining how antimicrobial resistance both emerges and proliferates among bacteria. Over time, ...

  20. Animation of Antimicrobial Resistance

    Medline Plus

    Full Text Available ... Veterinary Home Animal & Veterinary Safety & Health Antimicrobial Resistance Animation of Antimicrobial Resistance Share Tweet Linkedin Pin it ... Veterinary Medicine is cited as the corporate author. Animation Animation of Antimicrobial Resistance (WMV - 19.2MB) 9: ...

  1. Animation of Antimicrobial Resistance

    Medline Plus

    Full Text Available ... how antimicrobial resistance both emerges and proliferates among bacteria. Over time, the use of antimicrobial drugs will result in the development of resistant strains of bacteria, complicating clinician's efforts to select the appropriate antimicrobial ...

  2. Animation of Antimicrobial Resistance

    Medline Plus

    Full Text Available ... how antimicrobial resistance both emerges and proliferates among bacteria. Over time, the use of antimicrobial drugs will result in the development of resistant strains of bacteria, complicating clinician's efforts to select the appropriate antimicrobial ...

  3. Animation of Antimicrobial Resistance

    Medline Plus

    Full Text Available ... Veterinary Home Animal & Veterinary Safety & Health Antimicrobial Resistance Animation of Antimicrobial Resistance Share Tweet Linkedin Pin it ... Veterinary Medicine is cited as the corporate author. Animation Animation of Antimicrobial Resistance (WMV - 19.2MB) 9: ...

  4. Animation of Antimicrobial Resistance

    Medline Plus

    Full Text Available ... Animal & Veterinary Safety & Health Antimicrobial Resistance Animation of Antimicrobial Resistance Share Tweet Linkedin Pin it More sharing options ... CVM) produced a nine-minute animation explaining how antimicrobial resistance both emerges and proliferates among bacteria. Over time, ...

  5. Mapping the solid-state properties of crystalline lysozyme during pharmaceutical unit-operations.

    Science.gov (United States)

    Mohammad, Mohammad Amin; Grimsey, Ian M; Forbes, Robert T

    2015-10-10

    Bulk crystallisation of protein therapeutic molecules towards their controlled drug delivery is of interest to the biopharmaceutical industry. The complexity of biotherapeutic molecules is likely to lead to complex material properties of crystals in the solid state and to complex transitions. This complexity is explored using batch crystallised lysozyme as a model. The effects of drying and milling on the solid-state transformations of lysozyme crystals were monitored using differential scanning calorimetry (DSC), X-ray powder diffraction (XRPD), FT-Raman, and enzymatic assay. XRPD was used to characterise crystallinity and these data supported those of crystalline lysozyme which gave a distinctive DSC thermogram. The apparent denaturation temperature (Tm) of the amorphous lysozyme was ∼201 °C, while the Tm of the crystalline form was ∼187 °C. Raman spectra supported a more α-helix rich structure of crystalline lysozyme. This structure is consistent with reduced cooperative unit sizes compared to the amorphous lysozyme and is consistent with a reduction in the Tm of the crystalline form. Evidence was obtained that milling also induced denaturation in the solid-state, with the denatured lysozyme showing no thermal transition. The denaturation of the crystalline lysozyme occurred mainly through its amorphous form. Interestingly, the mechanical denaturation of lysozyme did not affect its biological activity on dissolution. Lysozyme crystals on drying did not become amorphous, while milling-time played a crucial role in the crystalline-amorphous-denatured transformations of lysozyme crystals. DSC is shown to be a key tool to monitor quantitatively these transformations.

  6. Animation of Antimicrobial Resistance

    Medline Plus

    Full Text Available ... More in Antimicrobial Resistance National Antimicrobial Resistance Monitoring ... Note: If you need help accessing information in different file formats, see Instructions for Downloading ...

  7. Animation of Antimicrobial Resistance

    Medline Plus

    Full Text Available ... More in Antimicrobial Resistance National Antimicrobial Resistance Monitoring ... Note: If you need help accessing information in different file formats, see Instructions for Downloading ...

  8. Animation of Antimicrobial Resistance

    Science.gov (United States)

    ... Animal & Veterinary Cosmetics Tobacco Products Animal & ... antimicrobial resistance both emerges and proliferates among bacteria. Over time, the use of antimicrobial drugs will result in the development ...

  9. High-level recombinant human lysozyme expressed in milk of transgenic pigs can inhibit the growth of Escherichia coli in the duodenum and influence intestinal morphology of sucking pigs.

    Science.gov (United States)

    Lu, Dan; Li, Qiuyan; Wu, Zhibin; Shang, Shengzhe; Liu, Shen; Wen, Xiao; Li, Zhiyuan; Wu, Fangfang; Li, Ning

    2014-01-01

    Lysozyme is often used as a feed additive and acts as an antimicrobial protein that enhances immune function and defends against pathogenic bacteria in pigs. In this study, we genetically added recombinant human lysozyme (rhLZ) to sow milk by somatic cell nuclear transfer and investigated whether the presence of recombinant human lysozyme can influence intestinal microbiota and morphology in sucking pigs. We generated transgenic cloned pigs and the first-generation hybrids (F1) produced high levels of rhLZ in milk. The average concentration of rhLZ was 116.34 ± 24.46 mg/L in the milk of F1 sows, which was 1500-fold higher than that of the native pig lysozyme. In vitro, it was demonstrated that rhLZ in milk of transgenic pigs had enzyme levels at 92,272 ± 26,413 U/mL. In a feeding experiment, a total of 40 newborn piglets were nursed by four transgenic sows and four sibling non-transgenic sows (F1), with five piglets per gilt. The piglets were allowed to nurse for 21 days and the sow milk was the only source of nutrition for the piglets. All piglets were slaughtered on postnatal day 22. Six types of bacteria were cultured and analyzed to detect the impact of rhLZ on gut microbiota. The number of Escherichia coli in the duodenum of piglets reared by transgenic sows was significantly decreased (ptransgenic cloned pigs and elevated lysozyme level in nuring piglets. The results of the feeding experiments demonstrated that rhLZ-enhanced milk can inhibit the growth of E. coli in the duodenum and positively influence intestinal morphology without adversely affecting weight gain or piglet growth.

  10. Structural basis of protein oxidation resistance: a lysozyme study.

    Directory of Open Access Journals (Sweden)

    Marion Girod

    Full Text Available Accumulation of oxidative damage in proteins correlates with aging since it can cause irreversible and progressive degeneration of almost all cellular functions. Apparently, native protein structures have evolved intrinsic resistance to oxidation since perfectly folded proteins are, by large most robust. Here we explore the structural basis of protein resistance to radiation-induced oxidation using chicken egg white lysozyme in the native and misfolded form. We study the differential resistance to oxidative damage of six different parts of native and misfolded lysozyme by a targeted tandem/mass spectrometry approach of its tryptic fragments. The decay of the amount of each lysozyme fragment with increasing radiation dose is found to be a two steps process, characterized by a double exponential evolution of their amounts: the first one can be largely attributed to oxidation of specific amino acids, while the second one corresponds to further degradation of the protein. By correlating these results to the structural parameters computed from molecular dynamics (MD simulations, we find the protein parts with increased root-mean-square deviation (RMSD to be more susceptible to modifications. In addition, involvement of amino acid side-chains in hydrogen bonds has a protective effect against oxidation Increased exposure to solvent of individual amino acid side chains correlates with high susceptibility to oxidative and other modifications like side chain fragmentation. Generally, while none of the structural parameters alone can account for the fate of peptides during radiation, together they provide an insight into the relationship between protein structure and susceptibility to oxidation.

  11. Laser ablation dynamics and production of thin films of lysozyme

    DEFF Research Database (Denmark)

    Canulescu, Stela; Schou, Jørgen; Amoruso, S.;

    produced thin films of average thickness up to 300 nm, which not only contained a significant amount of intact molecules, but also maintained the bioactivity. These films were produced by a nanosecond laser in the UV regime at 355 nm with 2 J/cm2. The surprising fact that these molecules can be transferred....... This is the first time the ablation by fs-lasers of a protein has been recorded quantitatively. Films of lysozyme produced by fs-laser irradiation were analyzed by MALDI and a significant number of intact molecules in the films with fs-laser deposition was found as well....

  12. Observance of polymorphic behaviour during dissolution of insulin and lysozyme

    Directory of Open Access Journals (Sweden)

    A. Bernardo

    2005-09-01

    Full Text Available Although protein crystallization is a unit operation with potentially high separation factors, it has not been widely used in industry. Protein crystallization studies and practices have hitherto been largely limited to crystallography protocols. Knowledge of the behaviour of protein in solution would help to overcome empiric limitations in protein crystallisation. Thus, dissolution of porcine insulin and hen egg white lysozyme was studied and an unusual variation in solute concentration, with a concentration peak for short dissolution times, was verified. Polymorphic behaviour of protein in solution was observed, which altered physical properties such as solubility.

  13. Listeria monocytogenes Is Resistant to Lysozyme through the Regulation, Not the Acquisition, of Cell Wall-Modifying Enzymes

    OpenAIRE

    Burke, TP; Loukitcheva, A; Zemansky, J; Wheeler, R; Boneca, IG; Portnoy, DA

    2014-01-01

    Listeria monocytogenes is a Gram-positive facultative intracellular pathogen that is highly resistant to lysozyme, a ubiquitous enzyme of the innate immune system that degrades cell wall peptidoglycan. Two peptidoglycan-modifying enzymes, PgdA and OatA, confer lysozyme resistance on L. monocytogenes; however, these enzymes are also conserved among lysozyme-sensitive nonpathogens. We sought to identify additional factors responsible for lysozyme resistance in L. monocytogenes. A forward geneti...

  14. Listeria monocytogenes Is Resistant to Lysozyme through the Regulation, Not the Acquisition, of Cell Wall-Modifying Enzymes

    OpenAIRE

    Burke, Thomas P.; Loukitcheva, Anastasia; Zemansky, Jason; Wheeler, Richard; Boneca, Ivo G.; Portnoy, Daniel A.

    2014-01-01

    Listeria monocytogenes is a Gram-positive facultative intracellular pathogen that is highly resistant to lysozyme, a ubiquitous enzyme of the innate immune system that degrades cell wall peptidoglycan. Two peptidoglycan-modifying enzymes, PgdA and OatA, confer lysozyme resistance on L. monocytogenes; however, these enzymes are also conserved among lysozyme-sensitive nonpathogens. We sought to identify additional factors responsible for lysozyme resistance in L. monocytogenes. A forward geneti...

  15. Isothermal Titration Calorimetry and Macromolecular Visualization for the Interaction of Lysozyme and Its Inhibitors

    Science.gov (United States)

    Wei, Chin-Chuan; Jensen, Drake; Boyle, Tiffany; O'Brien, Leah C.; De Meo, Cristina; Shabestary, Nahid; Eder, Douglas J.

    2015-01-01

    To provide a research-like experience to upper-division undergraduate students in a biochemistry teaching laboratory, isothermal titration calorimetry (ITC) is employed to determine the binding constants of lysozyme and its inhibitors, N-acetyl glucosamine trimer (NAG[subscript 3]) and monomer (NAG). The extremely weak binding of lysozyme/NAG is…

  16. Laser ablation of lysozyme with UV, visible and infrared femto- and nanosecond pulses

    DEFF Research Database (Denmark)

    Schou, Jørgen; Canulescu, Stela; Matei, Andreea

    industry. Lysozyme molecules do not absorb energy for wavelengths above 310 nm, but nevertheless there is a strong mass loss by ablation for laser irradiation in the visible regime. The total ablation yield of lysozyme at 355 nm and at 2 J/cm2 is about 155 µg/pulse, possibly one of the highest ablation...

  17. Crystallization of Hevamine, an Enzyme with Lysozyme/Chitinase Activity from Hevea brasiliensis Latex

    NARCIS (Netherlands)

    ROZEBOOM, HJ; BUDIANI, A; BEINTEMA, JJ

    1990-01-01

    Hevamine, an enzyme with both lysozyme and chitinase activity, was isolated and purified from Hevea brasiliensis (rubber tree) latex. The enzyme (molecular weight 29,000) is homologous to certain “pathogenesis-related” proteins from plants, but not to hen egg-white or phage T4 lysozyme. To

  18. Isothermal Titration Calorimetry and Macromolecular Visualization for the Interaction of Lysozyme and Its Inhibitors

    Science.gov (United States)

    Wei, Chin-Chuan; Jensen, Drake; Boyle, Tiffany; O'Brien, Leah C.; De Meo, Cristina; Shabestary, Nahid; Eder, Douglas J.

    2015-01-01

    To provide a research-like experience to upper-division undergraduate students in a biochemistry teaching laboratory, isothermal titration calorimetry (ITC) is employed to determine the binding constants of lysozyme and its inhibitors, N-acetyl glucosamine trimer (NAG[subscript 3]) and monomer (NAG). The extremely weak binding of lysozyme/NAG is…

  19. Production of active lysozyme films by matrix assisted pulsed laser evaporation at 355 nm

    DEFF Research Database (Denmark)

    Purice, Andreea; Schou, Jørgen; Kingshott, P.;

    2007-01-01

    Thin lysozyme films have been produced in a dry environment by MAPLE (matrix assisted pulsed laser evaporation) from a water ice matrix irradiated by laser light at 355 nm above the absorption threshold of the protein. A significant part of the lysozyme molecules are transferred to the film without...

  20. Characterization of lysozyme films produced by matrix assisted pulsed laser evaporation (MAPLE)

    DEFF Research Database (Denmark)

    Purice, Andreea; Schou, Jørgen; Kingshott, Peter

    2007-01-01

    Thin lysozyme films of thickness up to more than 100 nm have been produced in a dry environment by MAPLE (matrix assisted pulsed laser evaporation) from a water ice matrix. Analysis of the films demonstrates that a significant part of the lysozyme molecules is transferred to the substrate without...

  1. The effects of xylitol and sorbitol on lysozyme- and peroxidase-related enzymatic and candidacidal activities.

    Science.gov (United States)

    Kim, Bum-Soo; Chang, Ji-Youn; Kim, Yoon-Young; Kho, Hong-Seop

    2015-07-01

    To investigate whether xylitol and sorbitol affect enzymatic and candidacidal activities of lysozyme, the peroxidase system, and the glucose oxidase-mediated peroxidase system. Xylitol and sorbitol were added to hen egg-white lysozyme, bovine lactoperoxidase, glucose oxidase-mediated peroxidase, and whole saliva in solution and on hydroxyapatite surfaces. The enzymatic activities of lysozyme, peroxidase, and glucose oxidase-mediated peroxidase were determined by the turbidimetric method, the NbsSCN assay, and production of oxidized o-dianisidine, respectively. Candidacidal activities were determined by comparing colony forming units using Candida albicans ATCC strains 10231, 11006, and 18804. While xylitol and sorbitol did not affect the enzymatic activity of hen egg-white lysozyme both in solution and on hydroxyapatite surfaces, they did inhibit the enzymatic activity of salivary lysozyme significantly in solution, but not on the surfaces. Xylitol and sorbitol enhanced the enzymatic activities of both bovine lactoperoxidase and salivary peroxidase significantly in a dose-dependent manner in solution, but not on the surfaces. Sorbitol, but not xylitol, inhibited the enzymatic activity of glucose oxidase-mediated peroxidase significantly. Both xylitol and sorbitol did not affect candidacidal activities of hen egg-white lysozyme, the bovine lactoperoxidase system, or the glucose oxidase-mediated bovine lactoperoxidase system. Xylitol and sorbitol inhibited salivary lysozyme activity, but enhanced both bovine lactoperoxidase and salivary peroxidase activities significantly in solution. Xylitol and sorbitol did not augment lysozyme- and peroxidase-related candidacidal activities. Copyright © 2015 Elsevier Ltd. All rights reserved.

  2. Suppressive effects of lysozyme on polyphosphate-mediated vascular inflammatory responses

    Energy Technology Data Exchange (ETDEWEB)

    Chung, Jiwoo [College of Pharmacy, CMRI, Research Institute of Pharmaceutical Sciences, BK21 Plus KNU Multi-Omics Based Creative Drug Research Team, Kyungpook National University, Daegu 41566 (Korea, Republic of); Ku, Sae-Kwang [Department of Anatomy and Histology, College of Korean Medicine, Daegu Haany University, Gyeongsan 38610 (Korea, Republic of); Lee, Suyeon [College of Pharmacy, CMRI, Research Institute of Pharmaceutical Sciences, BK21 Plus KNU Multi-Omics Based Creative Drug Research Team, Kyungpook National University, Daegu 41566 (Korea, Republic of); Bae, Jong-Sup, E-mail: baejs@knu.ac.kr [College of Pharmacy, CMRI, Research Institute of Pharmaceutical Sciences, BK21 Plus KNU Multi-Omics Based Creative Drug Research Team, Kyungpook National University, Daegu 41566 (Korea, Republic of)

    2016-06-10

    Lysozyme, found in relatively high concentration in blood, saliva, tears, and milk, protects us from the ever-present danger of bacterial infection. Previous studies have reported proinflammatory responses of endothelial cells to the release of polyphosphate(PolyP). In this study, we examined the anti-inflammatory responses and mechanisms of lysozyme and its effects on PolyP-induced septic activities in human umbilical vein endothelial cells (HUVECs) and mice. The survival rates, septic biomarker levels, behavior of human neutrophils, and vascular permeability were determined in PolyP-activated HUVECs and mice. Lysozyme suppressed the PolyP-mediated vascular barrier permeability, upregulation of inflammatory biomarkers, adhesion/migration of leukocytes, and activation and/or production of nuclear factor-κB, tumor necrosis factor-α, and interleukin-6. Furthermore, lysozyme demonstrated protective effects on PolyP-mediated lethal death and the levels of the related septic biomarkers. Therefore, these results indicated the therapeutic potential of lysozyme on various systemic inflammatory diseases, such as sepsis or septic shock. -- Highlights: •PolyP is shown to be an important mediator of vascular inflammation. •Lysozyme inhibited PolyP-mediated hyperpermeability. •Lysozyme inhibited PolyP-mediated septic response. •Lysozyme reduced PolyP-induced septic mortality.

  3. Crystallization of Hevamine, an Enzyme with Lysozyme/Chitinase Activity from Hevea brasiliensis Latex

    NARCIS (Netherlands)

    ROZEBOOM, HJ; BUDIANI, A; BEINTEMA, JJ

    1990-01-01

    Hevamine, an enzyme with both lysozyme and chitinase activity, was isolated and purified from Hevea brasiliensis (rubber tree) latex. The enzyme (molecular weight 29,000) is homologous to certain “pathogenesis-related” proteins from plants, but not to hen egg-white or phage T4 lysozyme. To investiga

  4. Synergistic inhibition of Clostridium difficile with nisin-lysozyme combination treatment.

    Science.gov (United States)

    Chai, Changhoon; Lee, Kyung-Soo; Oh, Se-Wook

    2015-08-01

    Clostridium difficile vegetative cells were not inhibited completely after a 120-min treatment with 40 nM nisin or 0.8 mM lysozyme. However, these cells were completely inhibited after only a 30-min incubation with both 20 nM nisin and 0.2 mM lysozyme.

  5. Stability of lysozyme in aqueous extremolyte solutions during heat shock and accelerated thermal conditions

    NARCIS (Netherlands)

    Avanti, Christina; Saluja, Vinay; Van Streun, Erwin L. P.; Frijlink, Henderik W.; Hinrichs, Wouter L. J.

    2014-01-01

    The purpose of this study was to investigate the stability of lysozyme in aqueous solutions in the presence of various extremolytes (betaine, hydroxyectoine, trehalose, ectoine, and firoin) under different stress conditions. The stability of lysozyme was determined by Nile red Fluorescence Spectrosc

  6. The Plasmid-Encoded Regulator Activates Factors Conferring Lysozyme Resistance on Enteropathogenic Escherichia coli Strains▿

    Science.gov (United States)

    Salinger, Nina; Kokona, Bashkim; Fairman, Robert; Okeke, Iruka N.

    2009-01-01

    We demonstrate that enhanced lysozyme resistance of enteropathogenic Escherichia coli requires the plasmid-encoded regulator, Per, and is mediated by factors outside the locus for enterocyte effacement. EspC, a Per-activated serine protease autotransporter protein, conferred enhanced resistance on nonpathogenic E. coli, and a second Per-regulated, espC-independent lysozyme resistance mechanism was identified. PMID:18997020

  7. The plasmid-encoded regulator activates factors conferring lysozyme resistance on enteropathogenic Escherichia coli strains.

    Science.gov (United States)

    Salinger, Nina; Kokona, Bashkim; Fairman, Robert; Okeke, Iruka N

    2009-01-01

    We demonstrate that enhanced lysozyme resistance of enteropathogenic Escherichia coli requires the plasmid-encoded regulator, Per, and is mediated by factors outside the locus for enterocyte effacement. EspC, a Per-activated serine protease autotransporter protein, conferred enhanced resistance on nonpathogenic E. coli, and a second Per-regulated, espC-independent lysozyme resistance mechanism was identified.

  8. Thermodynamic Exploration of Eosin-Lysozyme Binding: A Physical Chemistry and Biochemistry Laboratory Experiment

    Science.gov (United States)

    Huisman, Andrew J.; Hartsell, Lydia R.; Krueger, Brent P.; Pikaart, Michael J.

    2010-01-01

    We developed a modular pair of experiments for use in the undergraduate physical chemistry and biochemistry laboratories. Both experiments examine the thermodynamics of the binding of a small molecule, eosin Y, to the protein lysozyme. The assay for binding is the quenching of lysozyme fluorescence by eosin through resonant energy transfer. In…

  9. Surface morphology of thin lysozyme films produced by matrix-assisted pulsed laser evaporation (MAPLE)

    DEFF Research Database (Denmark)

    Purice, Andreea; Schou, Jørgen; Pryds, Nini;

    2007-01-01

    Thin films of the protein, lysozyme, have been deposited by the matrix-assisted pulsed laser evaporation (MAPLE) technique. Frozen targets of 0.3-1.0 wt.% lysozyme dissolved in ultrapure water were irradiated by laser light at 355 mn with a fluence of 2 J/cm(2). The surface quality of the thin ly...

  10. Multi-model blending

    Energy Technology Data Exchange (ETDEWEB)

    Hamann, Hendrik F.; Hwang, Youngdeok; van Kessel, Theodore G.; Khabibrakhmanov, Ildar K.; Muralidhar, Ramachandran

    2016-10-18

    A method and a system to perform multi-model blending are described. The method includes obtaining one or more sets of predictions of historical conditions, the historical conditions corresponding with a time T that is historical in reference to current time, and the one or more sets of predictions of the historical conditions being output by one or more models. The method also includes obtaining actual historical conditions, the actual historical conditions being measured conditions at the time T, assembling a training data set including designating the two or more set of predictions of historical conditions as predictor variables and the actual historical conditions as response variables, and training a machine learning algorithm based on the training data set. The method further includes obtaining a blended model based on the machine learning algorithm.

  11. Blended learning in anatomy

    DEFF Research Database (Denmark)

    Østergaard, Gert Værge; Brogner, Heidi Marie

    2016-01-01

    behind DBR is that new knowledge is generated through processes that simultaneously develop, test and improve a design, in this case, an educational design (1) The main principles used in the project is blended learning and flipped learning (2). …"I definitely learn best in practice, but the theory...... in working with the assignments in the classroom."... External assesor, observer and interviewer Based on the different evaluations, the conclusion are that the blended learning approach combined with the ‘flipped classroom’ is a very good way to learn and apply the anatomy, both for the students......The aim of the project was to bridge the gap between theory and practice by working more collaboratively, both peer-to-peer and between student and lecturer. Furthermore the aim was to create active learning environments. The methodology of the project is Design-Based Research (DBR). The idea...

  12. Characterization of an Antimicrobial Extract from Elaeagnus angustifolia

    Directory of Open Access Journals (Sweden)

    Mohammad Hossein Dehghan

    2014-07-01

    Full Text Available Background: According to ethnobotanical data, Elaeagnus angustifolia fruit has wound healing activity, anti-inflammatory effect and antifebrile prosperities. Objectives: This study was performed as to the best of our knowledge; there has been no scientific report on the characterization of antimicrobial effect of E. angustifolia extract. Materials and Methods: An aqueous extract of Elaeagnus angustifolia was prepared and antimicrobial activity tests were performed on various target cultures. Minimal inhibitory concentration (MIC and minimal bactericidal concentration (MBC of the extract was done using the broth dilution technique. To characterize the extract, shelf life, thermal and pH stability, effects of detergents such as Tween 80, Tween 20, Triton X100, toluene and enzymes on the antimicrobial activity of Elaeagnus angustifolia extract, were examined. Results: The MIC values ranged from 7.5 to 0.1 mg/mL, showing maximum activity (1.62 mg/mL against E. coli. Similarly, the MBC of the extract against E. coli was 1.62 mg/mL. Antimicrobial activity of the extract was relatively stable when kept in the refrigerator for 60 days. The antimicrobial activity of Elaeagnus angustifolia extract was absolutely stable at temperatures up to 700° C. After exposure of the Elaeagnus angustifolia extract to different pH solutions in the range of 4-10, almost 100% residual activity was found against E. coli at pH 4, 5, 6, and 7. Treatment of the extract with detergents, lipase and lysozyme eliminated its antimicrobial activity. Conclusions: Our study gives an indication of the presence of promising antimicrobial compounds and provides basic information about the nature of the Elaeagnus angustifolia extract. Future studies should elucidate the components responsible for antimicrobial activity of these extracts against target cultures.

  13. Effect Mechanism of Structure-Changed Water on Heat Stability of Lysozyme

    Institute of Scientific and Technical Information of China (English)

    赵林; 谭欣

    2003-01-01

    Based on the mechanism of the effect of hydration on the heat stability of lysozyme and the theory of water molecule clusters, the effect of structure-changed water on heat stability of lysozyme has been studied. The results obtained by differential scanning calorimetry (DSC) showed that the thermal denaturation temperature of lysozyme had been elevated 8.47 K through hydration of lysozyme with processed water whose structure had been changed so it was called "structured water" compared to ordinary water. The reason is that structured water changed the dipole moment of water molecules and easily formed cyclic water hexamer or cage-like water hexamer, so that the interacting force of maintaining three-dimensional conformation of lysozyme could be reinforced.

  14. Study of Growth Mechanism of Lysozyme Crystal by Batch Crystallization Method

    Institute of Scientific and Technical Information of China (English)

    Hai Liang CUI; Yong YU; Wan Chun CHEN; Qi KANG

    2006-01-01

    The lysozyme crystals were made by batch crystallization method and the distribution of aggregate in solution were measured by dynamic light scattering. The results showed that the dimension of aggregate increased with the increase of the concentration of lysozyme and NaC1,lysozyme molecules aggregated gradually in solution and finally arrived at balance each other.The higher the concentrations of lysozyme and NaC1 were, the faster the growth rate of (110) face was. The growth rates of lysozyme crystal were obtained by a Zeiss microscope, and the effective surface energy (α) of growing steps were calculated about 4.01×l0-8 J.cm-2 according to the model of multiple two-dimensional nucleation mechanism.

  15. [Lysozyme in the treatment of juvenile laryngeal papillomatosis. A new concept in its etiopathogenesis].

    Science.gov (United States)

    Altamar-Ríos, J

    1990-01-01

    The A. inform about the results achieved with lysozyme chlorhydrate in the treatment of 15 patients with juvenile laryngeal papillomatosis. The lysozyme is an electropositive enzyme which synthesis is related to the degree of proteins and vitamin B complex ingestion. Lysozyme is a component of the immunitary inespecific system, serving to prevent against HPV-DNA at the level of the secretory film of the mucociliary apparatus of the respiratory mucous membrane. Furthermore, lysozyme hydrolyzes the mucopolysaccharide of the connective tissue and inhibits the virus-DNA replication. 100-300 mgr daily during 30-60 days simultaneously with hyperproteic diet and vitamin B complex (after correction of the nutrimental deficiencies) brought about the evanishment of papillomatosis. The A. suggest that the predisposition to infection by virus DNA is primarily of immunitary origin, because of lysozyme deficiency, and secondary due to a low intake of proteins and vitamin B complex.

  16. Blending Canal Surfaces Based on PH Curves

    Institute of Scientific and Technical Information of China (English)

    Chen-Dong Xu; Fa-Lai Chen

    2005-01-01

    In this paper, a new method for blending two canal surfaces is proposed. The blending surface is itself a generalized canal surface, the spine curve of which is a PH (Pythagorean-Hodograph) curve. The blending surface possesses an attractive property - its representation is rational. The method is extensible to blend general surfaces as long as the blending boundaries are well-defined.

  17. Beneficial effects of increased lysozyme levels in Alzheimer's disease modelled in Drosophila melanogaster.

    Science.gov (United States)

    Sandin, Linnea; Bergkvist, Liza; Nath, Sangeeta; Kielkopf, Claudia; Janefjord, Camilla; Helmfors, Linda; Zetterberg, Henrik; Blennow, Kaj; Li, Hongyun; Nilsberth, Camilla; Garner, Brett; Brorsson, Ann-Christin; Kågedal, Katarina

    2016-10-01

    Genetic polymorphisms of immune genes that associate with higher risk to develop Alzheimer's disease (AD) have led to an increased research interest on the involvement of the immune system in AD pathogenesis. A link between amyloid pathology and immune gene expression was suggested in a genome-wide gene expression study of transgenic amyloid mouse models. In this study, the gene expression of lysozyme, a major player in the innate immune system, was found to be increased in a comparable pattern as the amyloid pathology developed in transgenic mouse models of AD. A similar pattern was seen at protein levels of lysozyme in human AD brain and CSF, but this lysozyme pattern was not seen in a tau transgenic mouse model. Lysozyme was demonstrated to be beneficial for different Drosophila melanogaster models of AD. In flies that expressed Aβ1-42 or AβPP together with BACE1 in the eyes, the rough eye phenotype indicative of toxicity was completely rescued by coexpression of lysozyme. In Drosophila flies bearing the Aβ1-42 variant with the Arctic gene mutation, lysozyme increased the fly survival and decreased locomotor dysfunction dose dependently. An interaction between lysozyme and Aβ1-42 in the Drosophila eye was discovered. We propose that the increased levels of lysozyme, seen in mouse models of AD and in human AD cases, were triggered by Aβ1-42 and caused a beneficial effect by binding of lysozyme to toxic species of Aβ1-42 , which prevented these from exerting their toxic effects. These results emphasize the possibility of lysozyme as biomarker and therapeutic target for AD. © 2016 The Authors. The FEBS Journal published by John Wiley & Sons Ltd on behalf of Federation of European Biochemical Societies.

  18. Lysozyme in water-acetonitrile mixtures: Preferential solvation at the inner edge of excess hydration

    Science.gov (United States)

    Sirotkin, Vladimir A.; Kuchierskaya, Alexandra A.

    2017-06-01

    Preferential solvation/hydration is an effective way for regulating the mechanism of the protein destabilization/stabilization. Organic solvent/water sorption and residual enzyme activity measurements were performed to monitor the preferential solvation/hydration of hen egg-white lysozyme at high and low water content in acetonitrile at 25 °C. The obtained results show that the protein destabilization/stabilization depends essentially on the initial hydration level of lysozyme and the water content in acetonitrile. There are three composition regimes for the dried lysozyme. At high water content, the lysozyme has a higher affinity for water than for acetonitrile. The residual enzyme activity values are close to 100%. At the intermediate water content, the dehydrated lysozyme has a higher affinity for acetonitrile than for water. A minimum on the residual enzyme activity curve was observed in this concentration range. At the lowest water content, the organic solvent molecules are preferentially excluded from the dried lysozyme, resulting in the preferential hydration. The residual catalytic activity is ˜80%, compared with that observed after incubation in pure water. Two distinct schemes are operative for the hydrated lysozyme. At high and intermediate water content, lysozyme is preferentially hydrated. However, in contrast to the dried protein, at the intermediate water content, the initially hydrated lysozyme has the increased preferential hydration parameters. At low water content, the preferential binding of the acetonitrile molecules to the initially hydrated lysozyme was detected. No residual enzyme activity was observed in the water-poor acetonitrile. Our data clearly show that the initial hydration level of the protein macromolecules is one of the key factors that govern the stability of the protein-water-organic solvent systems.

  19. Lysozyme Protein Solution with an Intermediate Range Order Structure

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Yun [National Institute of Standards and Technology (NIST); Porcar, L. [National Institute of Standards and Technology (NIST); Chen, Wei-Ren [ORNL; Chen, Jinhong [Memorial Sloan-Kettering Cancer Center; Falus, Peter [ORNL; Fratini, Emiliano [University of Florence; Faraone, Antonio [National Institute of Standards and Technology (NIST); Baglioni, P [University of Florence

    2011-01-01

    The formation of equilibrium clusters has been studied in both a prototypical colloidal system and protein solutions. The appearance of a low-Q correlation peak in small angle scattering patterns of lysozyme solution was attributed to the cluster-cluster correlation. Consequently, the presence of long-lived clusters has been established. By quantitatively analyzing both the SANS (small angle neutron scattering) and NSE (neutron spin echo) data of lysozyme solution using statistical mechanics models, we conclusively show in this paper that the appearance of a low-Q peak is not a signature of the formation of clusters. Rather, it is due to the formation of an intermediate range order structure governed by a short-range attraction and a long-range repulsion. We have further studied dynamic features of a sample with high enough concentration at which clusters are formed in solution. From the estimation of the mean square displacement by using short-time and long-time diffusion coefficient measured by NSE and NMR, we find that these clusters are not permanent but have a finite lifetime longer than the time required to diffuse over a distance of a monomer diameter.

  20. Lysozyme Aggregation and Fibrillation Monitored by Dynamic Light Scattering

    Science.gov (United States)

    Nemzer, Louis; Flanders, Bret; Schmit, Jeremy; Sorensen, Christopher

    2012-02-01

    The aggregation of amyloidogenic proteins provides a rich phase space with significant biomedical implications, including a link with several age-related diseases. We employed dynamic light scattering to monitor the aggregation of lysozyme, a model protein, from a monomeric state until the formation of micron-sized fibrils. For an aqueous lysozyme solution buffered at pH 2, the auto-correlation function of the scattered light intensity was found to be well-fit by a single exponential function with decay time τ = 1/(2Dq^2) = 0.25 ms, which corresponds to a mean hydrodynamic radius (RH) of 2.2 nm, very likely generated by monomers. Ethanol (4% v/v final concentration) induced a partial unfolding, to RH = 4.6 nm. The subsequent addition of 70 mM KCl was found to shrink the size back to RH = 2.5 nm, as expected when a denatured protein refolds due to partial screening of the intramolecular repulsion. However, further aggregation was not observed. At pH 4, using a low-salt acetate buffer, more ethanol (10% v/v) was required to initiate unfolding, but once it occurred, larger aggregates formed. These results are consistent with the model that partial unfolding, which exposes beta-motif secondary structure, is a prerequisite for aggregation and fibrillation, but the aggregation fate depends on the protein charge state (pH) and screening (salt concentration).

  1. Lysozyme's lectin-like characteristics facilitates its immune defense function

    KAUST Repository

    Zhang, Ruiyan

    2017-06-06

    Interactions between human lysozyme (HL) and the lipopolysaccharide (LPS) of Klebsiella pneumoniae O1, a causative agent of lung infection, were identified by surface plasmon resonance. To characterize the molecular mechanism of this interaction, HL binding to synthetic disaccharides and tetrasaccharides representing one and two repeating units, respectively, of the O-chain of this LPS were studied. pH-dependent structural rearrangements of HL after interaction with the disaccharide were observed through nuclear magnetic resonance. The crystal structure of the HL-tetrasaccharide complex revealed carbohydrate chain packing into the A, B, C, and D binding sites of HL, which primarily occurred through residue-specific, direct or water-mediated hydrogen bonds and hydrophobic contacts. Overall, these results support a crucial role of the Glu35/Asp53/Trp63/Asp102 residues in HL binding to the tetrasaccharide. These observations suggest an unknown glycan-guided mechanism that underlies recognition of the bacterial cell wall by lysozyme and may complement the HL immune defense function.

  2. Terahertz mechanical vibrations in lysozyme: Raman spectroscopy vs modal analysis

    Science.gov (United States)

    Carpinteri, Alberto; Lacidogna, Giuseppe; Piana, Gianfranco; Bassani, Andrea

    2017-07-01

    The mechanical behaviour of proteins is receiving an increasing attention from the scientific community. Recently it has been suggested that mechanical vibrations play a crucial role in controlling structural configuration changes (folding) which govern proteins biological function. The mechanism behind protein folding is still not completely understood, and many efforts are being made to investigate this phenomenon. Complex molecular dynamics simulations and sophisticated experimental measurements are conducted to investigate protein dynamics and to perform protein structure predictions; however, these are two related, although quite distinct, approaches. Here we investigate mechanical vibrations of lysozyme by Raman spectroscopy and linear normal mode calculations (modal analysis). The input mechanical parameters to the numerical computations are taken from the literature. We first give an estimate of the order of magnitude of protein vibration frequencies by considering both classical wave mechanics and structural dynamics formulas. Afterwards, we perform modal analyses of some relevant chemical groups and of the full lysozyme protein. The numerical results are compared to experimental data, obtained from both in-house and literature Raman measurements. In particular, the attention is focused on a large peak at 0.84 THz (29.3 cm-1) in the Raman spectrum obtained analyzing a lyophilized powder sample.

  3. Human Antimicrobial Peptides and Proteins

    Directory of Open Access Journals (Sweden)

    Guangshun Wang

    2014-05-01

    Full Text Available As the key components of innate immunity, human host defense antimicrobial peptides and proteins (AMPs play a critical role in warding off invading microbial pathogens. In addition, AMPs can possess other biological functions such as apoptosis, wound healing, and immune modulation. This article provides an overview on the identification, activity, 3D structure, and mechanism of action of human AMPs selected from the antimicrobial peptide database. Over 100 such peptides have been identified from a variety of tissues and epithelial surfaces, including skin, eyes, ears, mouths, gut, immune, nervous and urinary systems. These peptides vary from 10 to 150 amino acids with a net charge between −3 and +20 and a hydrophobic content below 60%. The sequence diversity enables human AMPs to adopt various 3D structures and to attack pathogens by different mechanisms. While α-defensin HD-6 can self-assemble on the bacterial surface into nanonets to entangle bacteria, both HNP-1 and β-defensin hBD-3 are able to block cell wall biosynthesis by binding to lipid II. Lysozyme is well-characterized to cleave bacterial cell wall polysaccharides but can also kill bacteria by a non-catalytic mechanism. The two hydrophobic domains in the long amphipathic α-helix of human cathelicidin LL-37 lays the basis for binding and disrupting the curved anionic bacterial membrane surfaces by forming pores or via the carpet model. Furthermore, dermcidin may serve as ion channel by forming a long helix-bundle structure. In addition, the C-type lectin RegIIIα can initially recognize bacterial peptidoglycans followed by pore formation in the membrane. Finally, histatin 5 and GAPDH(2-32 can enter microbial cells to exert their effects. It appears that granulysin enters cells and kills intracellular pathogens with the aid of pore-forming perforin. This arsenal of human defense proteins not only keeps us healthy but also inspires the development of a new generation of personalized

  4. Blended Learning in English Literature

    OpenAIRE

    Haugestad, Astrid

    2015-01-01

    Abstract Blended Learning This study investigates blended learning used in a course of English Literature and Culture in upper secondary school. It raises the question how the use of blended learning may promote and encourage learning in a course of English literature and culture. The study also compares traditional face-to-face classroom communication with communication mediated by digital artefacts. It has been important to go beyond the strictly technical issues ...

  5. Antimicrobial resistance

    DEFF Research Database (Denmark)

    Llor, Carl; Bjerrum, Lars

    2014-01-01

    -the-counter sale of antibiotics, the use of antimicrobial stewardship programmes, the active participation of clinicians in audits, the utilization of valid rapid point-of-care tests, the promotion of delayed antibiotic prescribing strategies, the enhancement of communication skills with patients with the aid...... is associated with an increased risk of adverse effects, more frequent re-attendance and increased medicalization of self-limiting conditions. Antibiotic overprescribing is a particular problem in primary care, where viruses cause most infections. About 90% of all antibiotic prescriptions are issued by general...... practitioners, and respiratory tract infections are the leading reason for prescribing. Multifaceted interventions to reduce overuse of antibiotics have been found to be effective and better than single initiatives. Interventions should encompass the enforcement of the policy of prohibiting the over...

  6. Exercise does not increase salivary lymphocytes, monocytes, or granulocytes, but does increase salivary lysozyme.

    Science.gov (United States)

    Gillum, Trevor; Kuennen, Matthew; McKenna, Zachary; Castillo, Micaela; Jordan-Patterson, Alex; Bohnert, Caitlin

    2017-07-01

    An increase in salivary leukocytes may contribute to the exercise-induced increase in salivary antimicrobial proteins (AMPs). However, exercise-induced changes in salivary leukocytes have not been studied. The purpose of the study was to describe salivary leukocyte changes with exercise. Participants (n = 11, 20.3 ± 0.8 years, 57.2 ± 7.6 ml kg(-1) min(-1) peak oxygen uptake ((VO) ̇2peak), 11.1 ± 3.9% body fat) ran for 45 min at 75% of VO2peak. Stimulated saliva (12 mL) was collected pre- and immediately post exercise. Saliva was filtered through a 30 µm filter before analysis of leukocytes (CD45(+)), granulocytes (CD45(+)CD15(+)), monocytes (CD45(+)CD14(+)), T-cells (CD45(+)CD3(+)), and B-cells (CD45(+)CD20(+)) using flow cytometry. Saliva was analysed for Lysozyme (Lys) using ELISA. Exercise did not alter any leukocyte subset. The major constituent of leukocytes pre-exercise were granulocytes (57.9 ± 30.3% compared with monocytes: 5.1 ± 2.7%, T-cells: 17.1 ± 8.9%, B-cells: 12.1 ± 10.2%) (P increased after exercise (pre: 5,170 ± 5,215 ng/min; post: 7,639 ± 4,140 ng/min) (P increased granulocytes, but does increase Lys. Further, these data suggest that an increase in salivary leukocytes is not needed to increase Lys.

  7. Controlled release properties of zein-fatty acid blend films for multiple bioactive compounds.

    Science.gov (United States)

    Arcan, Iskender; Yemenicioğlu, Ahmet

    2014-08-13

    To develop edible films having controlled release properties for multiple bioactive compounds, hydrophobicity and morphology of zein films were modified by blending zein with oleic (C18:1)Δ⁹, linoleic (C18:2)Δ(9,12), or lauric (C₁₂) acids in the presence of lecithin. The blend zein films showed 2-8.5- and 1.6-2.9-fold lower initial release rates for the model active compounds, lysozyme (LYS) and (+)-catechin (CAT), than the zein control films, respectively. The change of fatty acid chain length affected both CAT and LYS release rates while the change of fatty acid double bond number affected only the CAT release rate. The film morphologies suggested that the blend films owe their controlled release properties mainly to the microspheres formed within their matrix and encapsulation of active compounds. The blend films showed antilisterial activity and antioxidant activity up to 81 μmol Trolox/cm². The controlled release of multiple bioactive compounds from a single film showed the possibility of combining application of active and bioactive packaging technologies and improving not only safety and quality but also health benefits of packed food.

  8. Blended-Learning-Projekte im Unternehmen

    OpenAIRE

    Keller, Miriam; Back, Andrea

    2004-01-01

    Der Arbeitsbericht Blended-Learning-Projekte im Unternehmen liefert einen Beitrag zur Bearbeitung des Themas Blended Learning und liefert dem Leser einen Überblick und erste Anregungen zur Planung, Integration und Gestaltung von Blended-Learning-Konzepten im Unternehmen.

  9. Antimicrobial activity of innate immune molecules against Streptococcus pneumoniae, Moraxella catarrhalis and nontypeable Haemophilus influenzae

    Directory of Open Access Journals (Sweden)

    Teufert Karen

    2004-05-01

    Full Text Available Abstract Background Despite its direct connection to the nasopharynx which harbors otitis media pathogens as part of its normal flora, the middle ear cavity is kept free of these bacteria by as yet unknown mechanisms. Respiratory mucosal epithelia, including those of the middle ear and eustachian tube, secrete antimicrobial effectors including lysozyme, lactoferrin and β defensins-1 and -2. To elucidate the role of these innate immune molecules in the normal defense and maintenance of sterility of respiratory mucosa such as that of the middle ear, we assessed their effect on the respiratory pathogens nontypeable Haemophilus influenzae (NTHi 12, Moraxella catarrhalis 035E, and Streptococcus pneumoniae 3, and 6B. Methods Two assay methods, the radial assay and the liquid broth assay, were employed for testing the antimicrobial activity of the molecules. This was done in order to minimize the possibility that the observed effects were artifacts of any single assay system employed. Also, transmission electron microscopy (TEM was employed to evaluate the effect of antimicrobial innate immune molecules on OM pathogens. For the statistical analysis of the data, Student's t-test was performed. Results Results of the radial diffusion assay showed that β defensin-2 was active against all four OM pathogens tested, while treatment with β defensin-1 appeared to only affect M. catarrhalis. The radial assay results also showed that lysozyme was quite effective against S. pneumoniae 3 and 6B and was partially bacteriostatic/bactericidal against M. catarrhalis. Lysozyme however, appeared not to affect the growth of NTHi. Thus, lysozyme seems to have a more pronounced impact on the growth of the Gram-positive S. pneumoniae as compared to that of Gram-negative pathogens. Lactoferrin on the other hand, enhanced the growth of the bacteria tested. The results of the radial assays were confirmed using liquid broth assays for antimicrobial activity, and showed that

  10. Managing as blended care.

    Science.gov (United States)

    Mintzberg, H

    1994-09-01

    As part of a research project on managerial work based on a new model of the roles, the head nurse of a hospital unit was observed during a working day. Her work is described, with reference especially to the roles of leading, linking, controlling, and doing. Conclusions are drawn about the advantages of a craft style of management as opposed to the more traditional "boss" or professional styles. The author also discusses what those in general management can learn from those in nursing management, which seems best practiced out in the open, on one's feet, as a kind of blended care.

  11. Blended Learning on Campus

    DEFF Research Database (Denmark)

    Heilesen, Simon; Nielsen, Jørgen Lerche

    2004-01-01

    On the basis of a large-scale project implementing information and communication technology at Roskilde University, Denmark, this paper discusses ways of introducing technology-based blended learning in academic life. We examine some examples of use of systems for computer-mediated collabora......-tive learning and work in Danish Open University education as well as in courses on campus. We further suggest some possi-bilities for using technology in innovative ways, arguing that innovation is to be found, not in isolated instantiations of sys-tems, but in the form of a deliberate integration of all...... relevant ICT-features as a whole into the learning environment....

  12. The Release of Egg White Lysozyme Containing EDTA from Composite Edible Film Based on Whey Protein, Konjac Flour and Lipid

    Directory of Open Access Journals (Sweden)

    Mulia W. Apriliyani

    2014-01-01

    Full Text Available The objectives of this research were to find out the effect of EDTA addition on antibacterial spectrum broadening of lysozyme on Gram negative bacteria and the release of lysozyme from composite edible film made of whey protein, konjac glucomannan and several lipids type and content. The research were conducted with 2 steps. Step I: The addition of EDTA on lysozyme aquaeous (Lysozyme (mg/mL: EDTA (mg/mL = 11.14:8.14; 11.14:11.14 and 11.14:14.14 using Randomyzed Block Design, the variables were, antibacterial of lysozyme on Micrococcus lysodeikticus and Escherichia coli. Step II: Lipid content (5 and 10% and kind of lipid (butter, margarine, palm oil and beeswax using nested Randomyzed Block Design, the variables were lysozyme release, Water Vapor Permeability (WVP, protein solublity and microstructure of composite edible film. The results were, step I: the treatment didn’t gave significantly effect (p>0.05 on lysozyme activity. EDTA decrease cell membrane stabilization and lysozyme made lysis of cell membrane. EDTA chelate Ca2+ and Mg2+ salts as bridge between Lypopolysachcharide (LPS in outer membrane so LPS released from cell wall of Gram negative bacteria. Step II: The treatment didn’t gave significantly effect (p>0.05 on release of lysozyme and water vapour permeability, but gave significantly effect (p<0.05 on protein solubility. The release of lysozyme from composite edible film gave the best lysozyme release from beeswax 10% addition.

  13. Interaction between lysozyme and procyanidin: multilevel structural nature and effect of carbohydrates.

    Science.gov (United States)

    Liang, Miao; Liu, Rui; Qi, Wei; Su, Rongxin; Yu, Yanjun; Wang, Libing; He, Zhimin

    2013-06-01

    The interaction of procyanidins with proteins has aroused extensive attention due to its important relationship with the bioavailability and astringent property of polyphenols. In the present work, we have investigated the interactions of lysozyme with procyanidin dimer (B3) using various biophysical approaches, which aims to provide insights into the mechanism of protein/polyphenol aggregation. Procyanidin B3 spontaneously binds lysozyme, inducing the multilevel structural changes in lysozyme and the formation of insoluble complexes. The relationship between lysozyme aggregation and the loss of enzymatic activity was monitored using dynamic light scattering and fluorescence quenching. The influences of two carbohydrates (gum arabic and sucrose) on lysozyme/B3 aggregation were also studied. Gum arabic effectively inhibited the formation of insoluble aggregates, but was unable to restore the fluorescence and activity of lysozyme. However, sucrose concomitantly decreased the aggregate size with the recovery of fluorescence and lysozyme activity. These results proposed two probable mechanisms by which these two carbohydrates inhibit protein/polyphenol aggregation.

  14. Selectivity and localization of lysozyme uptake in contemporary hydrogel contact lens materials.

    Science.gov (United States)

    Heynen, Miriam; Babaei Omali, Negar; Fadli, Zohra; Coles-Brennan, Chantal; Subbaraman, Lakshman N; Jones, Lyndon

    2017-09-01

    The purpose of this study was to investigate the early and selective uptake of lysozyme and the location of deposited lysozyme on contemporary hydrogel contact lens (CL) materials after exposure to an artificial tear solution (ATS) for 16 h. Seven different hydrogel CL materials [polymacon, omafilcon A, nelfilcon A, nesofilcon A, ocufilcon B, etafilcon A (Acuvue Moist), and etafilcon A (Acuvue Define)] were incubated in an ATS for various times. Total protein deposition was determined using a modified Bradford technique. Lysozyme, lactoferrin, and albumin deposition on CLs were determined using (125)I-radiolabeling method. A confocal laser scanning microscopy (CLSM) technique was utilized to map the location of lysozyme uptake in an asymmetric environment. All lens materials had significant amounts of lysozyme after 1 min of exposure to ATS. After 16 h of incubation, higher levels of total protein deposited on the two etafilcon A-based lenses (Moist and Define), followed by ocufilcon B and both were significantly higher than all other CLs tested (p = 0.0001). The two etafilcon A materials (Moist and Define) also deposited the highest amounts of lysozyme (514.8 ± 28.4 and 527.1 ± 14.7 μg/lens respectively) when compared to other test CLs (p = 0.0001). The CLSM technique revealed that the non-ionic CLs tended to have symmetric distribution of lysozyme throughout the lens materials, while the ionic CLs had an asymmetric distribution, with the highest concentration of lysozyme on and near the exposed surface. The quantity and nature of proteins deposited on CLs varies, depending upon the chemical composition of the material. Among the various lenses tested, etafilcon A deposited the highest amount of total protein, most of it represented by lysozyme, which was largely located near the surface of the lens.

  15. Comparative evaluation of multi-purpose solutions in the stabilization of tear lysozyme.

    Science.gov (United States)

    Barniak, Vicki L; Burke, Susan E; Venkatesh, Srini

    2010-12-01

    The range and extent of tear proteins removed by various multi-purpose solutions has been investigated, but there is little information in the literature about their ability to prevent denaturation of tear proteins, particularly lysozyme. The purpose of this study was to determine the ability of Bausch+Lomb Biotrue™ multi-purpose solution and other care solutions to affect denaturation of lysozyme using a lysozyme activity assay. The test solutions used were: Biotrue multi-purpose solution, Bausch+Lomb renu(®) fresh™, formerly ReNu MultiPlus(®), Alcon OPTI-FREE RepleniSH, Alcon OPTI-FREE EXPRESS, CIBA VISION AQuify, and AMO COMPLETE Multi-Purpose Solution Easy Rub Formula. A phosphate-buffered saline (PBS) solution served as a control. The test and control solutions containing lysozyme were exposed to sodium dodecyl sulfate (SDS), a known denaturant of the enzyme. The assay was based on digestion of the cell wall of Micrococcus luteus in a suspension, a substrate sensitive to active lysozyme. Enzymatic activity against M. luteus was used to assess activity of lysozyme. The decrease in the turbidity of the cell wall suspension, a measure of relative enzyme activity, was determined by following the decrease in absorbance (at 450nm) over time using a spectrophotometer. Statistically significant greater stabilization of lysozyme was observed with Biotrue multi-purpose solution and renu fresh than with OPTI-FREE RepleniSH, OPTI-FREE EXPRESS, AQuify, COMPLETE Multi-Purpose Solution Easy Rub Formula, and a PBS control. The lysozyme activity assay revealed that Biotrue multi-purpose solution and renu fresh have the ability to stabilize lysozyme under conditions that typically denature the protein.

  16. Short fiber reinforced thermoplastic blends

    NARCIS (Netherlands)

    Malchev, P.G.

    2008-01-01

    The present thesis investigates the potential of short fiber reinforced thermoplastic blends, a combination of an immiscible polymer blend and a short fiber reinforced composite, to integrate the easy processing solutions available for short fiber reinforced composites with the high mechanical perfo

  17. The Basics of Blended Instruction

    Science.gov (United States)

    Tucker, Catlin R.

    2013-01-01

    Even though many of teachers do not have technology-rich classrooms, the rapidly evolving education landscape increasingly requires them to incorporate technology to customize student learning. Blended learning, with its mix of technology and traditional face-to-face instruction, is a great approach. Blended learning combines classroom learning…

  18. Blended Learning: An Innovative Approach

    Science.gov (United States)

    Lalima; Dangwal, Kiran Lata

    2017-01-01

    Blended learning is an innovative concept that embraces the advantages of both traditional teaching in the classroom and ICT supported learning including both offline learning and online learning. It has scope for collaborative learning; constructive learning and computer assisted learning (CAI). Blended learning needs rigorous efforts, right…

  19. Blended Learning: A Dangerous Idea?

    Science.gov (United States)

    Moskal, Patsy; Dziuban, Charles; Hartman, Joel

    2013-01-01

    The authors make the case that implementation of a successful blended learning program requires alignment of institutional, faculty, and student goals. Reliable and robust infrastructure must be in place to support students and faculty. Continuous evaluation can effectively track the impact of blended learning on students, faculty, and the…

  20. Classifying K-12 Blended Learning

    Science.gov (United States)

    Staker, Heather; Horn, Michael B.

    2012-01-01

    The growth of online learning in the K-12 sector is occurring both remotely through virtual schools and on campuses through blended learning. In emerging fields, definitions are important because they create a shared language that enables people to talk about the new phenomena. The blended-learning taxonomy and definitions presented in this paper…

  1. Short fiber reinforced thermoplastic blends

    NARCIS (Netherlands)

    Malchev, P.G.

    2008-01-01

    The present thesis investigates the potential of short fiber reinforced thermoplastic blends, a combination of an immiscible polymer blend and a short fiber reinforced composite, to integrate the easy processing solutions available for short fiber reinforced composites with the high mechanical perfo

  2. Blended Learning: A Dangerous Idea?

    Science.gov (United States)

    Moskal, Patsy; Dziuban, Charles; Hartman, Joel

    2013-01-01

    The authors make the case that implementation of a successful blended learning program requires alignment of institutional, faculty, and student goals. Reliable and robust infrastructure must be in place to support students and faculty. Continuous evaluation can effectively track the impact of blended learning on students, faculty, and the…

  3. Survey design for blended acquisition

    NARCIS (Netherlands)

    Blacquière, G.; Berkhout, A.J.; Verschuur, D.J.

    2009-01-01

    When designing an acquisition geometry for the case of source blending, it is important that the blended source arrays are capable of transmitting a wavefield with a large spatial and temporal bandwidth: the wavefield must be incoherent. We call this incoherent shooting. Furthermore, the array must

  4. Blended Learning Improves Science Education.

    Science.gov (United States)

    Stockwell, Brent R; Stockwell, Melissa S; Cennamo, Michael; Jiang, Elise

    2015-08-27

    Blended learning is an emerging paradigm for science education but has not been rigorously assessed. We performed a randomized controlled trial of blended learning. We found that in-class problem solving improved exam performance, and video assignments increased attendance and satisfaction. This validates a new model for science communication and education.

  5. Effect of antimicrobial peptides on colistin-susceptible and colistin-resistant strains of Klebsiella pneumoniae and Enterobacter asburiae.

    Science.gov (United States)

    Kádár, Béla; Kocsis, Béla; Kristof, Katalin; Tóth, Ákos; Szabó, Dóra

    2015-12-01

    In this study susceptibility to different antimicrobial peptides was investigated on colistin-susceptible and colistin-resistant identical pulsotype strains of KPC-2 producing Klebsiella pneumoniae ST258 as well as colistin-susceptible and colistin-resistant Enterobacter asburiae strains isolated from clinical samples. In our test, bacteria were exposed to 50 mg/ml lactoferrin, lysozyme and protamine - cationic antimicrobial peptides belonging to innate immune system and having structural similarity to polymyxins - in separate reactions. After 18 hours incubation of colonies were counted. 40% of colistin-resistant K. pneumoniae strains and 97% of colistin-susceptible counterpart strains were lysed by protamine whereas 87% and 100% colony forming unit decrease by lysozyme was seen, respectively. In the case of colistin-resistant E. asburiae strains 1 log10 cell count increase were observed after treatment with lysozyme and 1.56 log10 after lactoferrin exposure compared to the initial number whereas the colistin-susceptible showed no relevant cell count increase. Our findings suggest that acquired colistin-resistance in Enterobacteriaceae is associated with tolerance against antimicrobial peptides.

  6. Structure and stability of self-assembled actin-lysozyme complexes in salty water.

    Science.gov (United States)

    Sanders, Lori K; Guáqueta, Camilo; Angelini, Thomas E; Lee, Jae-Wook; Slimmer, Scott C; Luijten, Erik; Wong, Gerard C L

    2005-09-02

    Interactions between actin, an anionic polyelectrolyte, and lysozyme, a cationic globular protein, have been examined using a combination of synchrotron small-angle x-ray scattering and molecular dynamics simulations. Lysozyme initially bridges pairs of actin filaments, which relax into hexagonally coordinated columnar complexes comprised of actin held together by incommensurate one-dimensional close-packed arrays of lysozyme macroions. These complexes are found to be stable even in the presence of significant concentrations of monovalent salt, which is quantitatively explained from a redistribution of salt between the condensed and the aqueous phases.

  7. [Nature of tryptophan photooxidation products in lysozyme in the presence of methylene blue].

    Science.gov (United States)

    Churakova, N I; Kravchenko, N A; Serebriakov, E P; Kaverzneva, E D

    1976-05-01

    One out of six trytophan residues in two lysozyme modification, obtained under lysozyme photooxidation in the presence of methylene blue, is found to be oxidized to N'-formylkinurenine (in one modification) and to kinurenine (in the other modification). The transition of one modification into another via detaching of N'-formyl group by soft acid hydrolysis has shown that one and the same tryptophan residue is oxidized in both products, Possible mechanism of tryptophan oxidation to the products mentioned is discu-sed on the basis of the hypothesis on signlet mechanism of lysozyme photooxidation in the presence of methylene blue.

  8. A novel anti-inflammatory activity of lysozyme: modulation of serum complement activation

    Directory of Open Access Journals (Sweden)

    M. O. Ogundele

    1998-01-01

    Full Text Available Lysozyme is an ubiquitous enzyme found in most biological secretions and leukocytes. This study was aimed at investigating its interaction with other inflammatory mediators on mucosa surfaces, particularly the complement system. Lysozyme has been shown in our present study, to inhibit the haemolytic activity of serum complement in a dose-dependent fashion, when tested within the levels present in normal and inflamed breast-milk samples, and other mucosal secretions. This represents a new antiinflammatory action of lysozym e in relation to the serum complement, and the exact mode of the interaction need further studies.

  9. Combined effect of lysozyme and nisin at different incubation temperature and mild heat treatment on the probability of time to growth of Bacillus cereus.

    Science.gov (United States)

    Antolinos, Vera; Muñoz, Marina; Ros-Chumillas, María; Aznar, Arantxa; Periago, Paula M; Fernández, Pablo S

    2011-04-01

    Stochastic models can be useful to predict the risk of foodborne illness. The presence of Bacillus cereus in liquid egg can pose a serious hazard to the food industry, since a mild heat treatment cannot guarantee its complete inactivation. However, most of the information available in the scientific literature is deterministic, including growth of B. cereus. In this paper, a stochastic approach to evaluate growth of B. cereus cells influenced by different stresses (presence of nisin and lysozyme separately or in combination) was performed, using an individual-based approach of growth through OD measurements. Lag phase duration was derived from the growth curves obtained. From results obtained, histograms of the lag phase were generated and distributions were fitted. Normal and Weibull distributions were ranked as the bestfit distributions in experiments performed at 25 °C. At 16 °C, lag values (obtained in presence of combinations of both antimicrobials) were also fitted by a Gamma distribution. Predictions were compared with growth curves obtained in liquid egg exposed to mild heat, nisin and/or lysozyme to assess their validity.

  10. Neutron crystallographic studies of T4 lysozyme at cryogenic temperature.

    Science.gov (United States)

    Li, Le; Shukla, Shantanu; Meilleur, Flora; Standaert, Robert F; Pierce, Josh; Myles, Dean A A; Cuneo, Matthew J

    2017-07-13

    Bacteriophage T4 lysozyme (T4L) has been used as a paradigm for seminal biophysical studies on protein structure, dynamics, and stability. Approximately 700 mutants of this protein and their respective complexes have been characterized by X-ray crystallography; however, despite the high resolution diffraction limits attained in several studies, no hydrogen atoms were reported being visualized in the electron density maps. To address this, a 2.2 Å-resolution neutron data set was collected at 80 K from a crystal of perdeuterated T4L pseudo-wild type. We describe a near complete atomic structure of T4L, which includes the positions of 1737 hydrogen atoms determined by neutron crystallography. The cryogenic neutron model reveals explicit detail of the hydrogen bonding interactions in the protein, in addition to the protonation states of several important residues. © 2017 The Protein Society.

  11. Nucleation of lysozyme crystals under external electric and ultrasonic fields

    Science.gov (United States)

    Nanev, Christo N.; Penkova, Anita

    2001-11-01

    Preferred orientation along c-axis of hen-egg-white lysozyme (HEWL) crystals has been observed in an external electric field. Besides, the HEWL crystals grew predominantly on the cathode side of the glass cell. These facts were explained on the basis of a concept for specific spatial distribution of the positive electric charges on the individual HEWL molecules, and thus attributed to the (preferred) orientation of individual HEWL molecules in the solution, under these conditions. Ultrasonic field redoubles the nucleation rate of HEWL crystals, but does not change the number of building units in the critical nucleus. Taking into account the intermolecular binding energy, we conclude that ultrasonic field accelerates nucleation due to breaking of the protein crystals.

  12. Unravelling the structure of the pneumococcal autolytic lysozyme.

    Science.gov (United States)

    Monterroso, Begoña; López-Zumel, Consuelo; García, José L; Sáiz, José L; García, Pedro; Campillo, Nuria E; Menéndez, Margarita

    2005-10-01

    The LytC lysozyme of Streptococcus pneumoniae forms part of the autolytic system of this important pathogen. This enzyme is composed of a C-terminal CM (catalytic module), belonging to the GH25 family of glycosyl hydrolases, and an N-terminal CBM (choline-binding module), made of eleven homologous repeats, that specifically recognizes the choline residues that are present in pneumococcal teichoic and lipoteichoic acids. This arrangement inverts the general assembly pattern of the major pneumococcal autolysin, LytA, and the lytic enzymes encoded by pneumococcal bacteriophages that place the CBM (made of six repeats) at the C-terminus. In the present paper, a three-dimensional model of LytC built by homology modelling of each module and consistent with spectroscopic and hydrodynamic studies is shown. In addition, the putative catalytic-pair residues are identified. Despite the inversion in the modular arrangement, LytC and the bacteriophage-encoded Cpl-1 lysozyme most probably adopt a similar global fold. However, the distinct choline-binding ability and their substrate-binding surfaces may reflect a divergent evolution directed by the different roles played by them in the host (LytC) or in the bacteriophage (Cpl-1). The tight binding of LytC to the pneumococcal envelope, mediated by the acquisition of additional choline-binding repeats, could facilitate the regulation of the potentially suicidal activity of this autolysin. In contrast, a looser attachment of Cpl-1 to the cell wall and the establishment of more favourable interactions between its highly negatively charged catalytic surface and the positively charged chains of pneumococcal murein could enhance the lytic activity of the parasite-encoded enzyme and therefore liberation of the phage progeny.

  13. Combined effects of lactoferrin and lysozyme on Streptococcus pneumoniae killing.

    Science.gov (United States)

    André, G O; Politano, W R; Mirza, S; Converso, T R; Ferraz, L F C; Leite, L C C; Darrieux, M

    2015-12-01

    Streptococcus pneumoniae is a common colonizer of the human nasopharynx, which can occasionally spread to sterile sites, causing diseases such as otitis media, sinusitis, pneumonia, meningitis and bacteremia. Human apolactoferrin (ALF) and lysozyme (LZ) are two important components of the mucosal innate immune system, exhibiting lytic effects against a wide range of microorganisms. Since they are found in similar niches of the host, it has been proposed that ALF and LZ could act synergistically in controlling bacterial spread throughout the mucosa. The combination of ALF and LZ has been shown to enhance killing of different pathogens in vitro, with ALF facilitating the latter action of LZ. The aim of the present work was to investigate the combined effects of ALF and LZ on S pneumoniae. Concomitant addition of ALF and LZ had a synergistic killing effect on one of the pneumococci tested. Furthermore, the combination of ALF and ALZ was more bactericidal than lysozyme alone in all pneumococcal strains. Pneumococcal surface protein A (PspA), an important vaccine candidate, partially protects pneumococci from ALF mediated killing, while antibodies against one PspA enhance killing of the homologous strain by ALF. However, the serological variability of this molecule could limit the effect of anti-PspA antibodies on different pneumococci. Therefore, we investigated the ability of anti-PspA antibodies to increase ALF-mediated killing of strains that express different PspAs, and found that antisera to the N-terminal region of PspA were able to increase pneumococcal lysis by ALF, independently of the sequence similarities between the molecule expressed on the bacterial surface and that used to produce the antibodies. LF binding to the pneumococcal surface was confirmed by flow cytometry, and found to be inhibited in presence of anti-PspA antibodies. On a whole, the results suggest a contribution of ALF and LZ to pneumococcal clearance, and confirm PspA's ability to interact

  14. Blend or not to blend: a study investigating faculty members perceptions of blended teaching

    Directory of Open Access Journals (Sweden)

    Mehmet A Ocak

    2010-12-01

    Full Text Available This study examined faculty members’ perceptions of blended teaching from several perspectives. A total of 73 faculty members in Turkish Higher Education context participated in the study by completing an online survey that combined quantitative and qualitative approaches. Based on a data analysis, the faculty members’ perceptions were sorted into six categories: (a satisfaction with blended teaching, (b perceived impact on the role of the faculty, (c perceived impact on student learning, (d perceived impact on student motivation, (e advantages of blended teaching, and (f disadvantages of blended teaching. Findings indicated that faculty members were likely to agree that blended teaching provides a high degree of satisfaction and that it requires more time and commitment from the faculty. The faculty members perceived that blended teaching improves student learning and, to some extent, improves motivation. The faculty members also emphasized the importance of institutional support and the use of technology to mitigate student problems. This study presents these faculty members’ perceptions, which are helpful for those planning to implement a blended teaching approach, and makes suggestions for trouble-shooting and taking advantage of the opportunities in a blended environment successfully.

  15. Lysozyme activity and L(+)-lactic acid production in saliva in schoolchildren with high Lactobacillus counts.

    Science.gov (United States)

    Twetman, S; Dahllöf, G; Wikner, S

    1987-04-01

    Out of 374 schoolchildren, aged 13-15 yr, 42 with high counts of salivary lactobacilli (greater than or equal to 10(5] were selected for this study. Lysozyme activity in saliva and L(+)-lactic acid (LA) production after addition of glucose were determined. The mean values of lysozyme activity and LA concentration were 19.4 micrograms/ml and 1.4 mmol/l respectively. The levels of LA produced without addition of glucose were less than 0.2 mmol/l. The results showed a statistically significant (P less than 0.05) negative correlation between lysozyme activity and the levels of LA produced. The findings of this study suggest that lysozyme may be of importance in limiting acid production in saliva.

  16. An integrated process for purification of lysozyme, ovalbumin, and ovomucoid from hen egg white.

    Science.gov (United States)

    Roy, Ipsita; Rao, M V S; Gupta, Munishwar N

    2003-10-01

    This article describes an integrated process for simultaneous purification of lysozyme, ovalbumin, and ovomucoid from hen egg white. The crude egg white extract was passed through a cation exchanger Streamline trade mark SP and the bound lysozyme was eluted with 5% ammonium carbonate, pH 9.0, containing 1 M NaCl after elution of avidin. This partially purified lysozyme was further purified 639-fold on dye-linked cellulose beads. Ovalbumin and ovomucoid did not bind to Streamline SP. Ovalbumin could be precipitated from this unbound fraction by 5% trichloroacetic acid, and ovomucoid was removed from the supernatant by precipitation with ethanol. The yields of lysozyme, ovomucoid, and ovalbumin were 77, 94, and 98%, respectively. All the purified proteins showed single bands on sodium dodecyl sulfate polyacrylamide gel electrophoresis. All the steps are easily scalable, and the process described here can be used for large-scale simultaneous purification of these proteins in the pure form.

  17. Stability of lysozyme in aqueous extremolyte solutions during heat shock and accelerated thermal conditions.

    Directory of Open Access Journals (Sweden)

    Christina Avanti

    Full Text Available The purpose of this study was to investigate the stability of lysozyme in aqueous solutions in the presence of various extremolytes (betaine, hydroxyectoine, trehalose, ectoine, and firoin under different stress conditions. The stability of lysozyme was determined by Nile red Fluorescence Spectroscopy and a bioactivity assay. During heat shock (10 min at 70°C, betaine, trehalose, ectoin and firoin protected lysozyme against inactivation while hydroxyectoine, did not have a significant effect. During accelerated thermal conditions (4 weeks at 55°C, firoin also acted as a stabilizer. In contrast, betaine, hydroxyectoine, trehalose and ectoine destabilized lysozyme under this condition. These findings surprisingly indicate that some extremolytes can stabilize a protein under certain stress conditions but destabilize the same protein under other stress conditions. Therefore it is suggested that for the screening extremolytes to be used for protein stabilization, an appropriate storage conditions should also be taken into account.

  18. Antimicrobial (Drug) Resistance

    Science.gov (United States)

    ... the past 70 years, antimicrobial drugs, such as antibiotics, have been successfully used to treat patients with bacterial and infectious diseases. Why Is the Study of Antimicrobial (Drug) Resistance a Priority for NIAID? Over time, many infectious ...

  19. Animation of Antimicrobial Resistance

    Medline Plus

    Full Text Available ... Animal & Veterinary Cosmetics Tobacco Products Animal & ... antimicrobial resistance both emerges and proliferates among bacteria. Over time, the use of antimicrobial drugs will result in the development ...

  20. Listeria monocytogenes is resistant to lysozyme through the regulation, not the acquisition, of cell wall-modifying enzymes.

    Science.gov (United States)

    Burke, Thomas P; Loukitcheva, Anastasia; Zemansky, Jason; Wheeler, Richard; Boneca, Ivo G; Portnoy, Daniel A

    2014-11-01

    Listeria monocytogenes is a Gram-positive facultative intracellular pathogen that is highly resistant to lysozyme, a ubiquitous enzyme of the innate immune system that degrades cell wall peptidoglycan. Two peptidoglycan-modifying enzymes, PgdA and OatA, confer lysozyme resistance on L. monocytogenes; however, these enzymes are also conserved among lysozyme-sensitive nonpathogens. We sought to identify additional factors responsible for lysozyme resistance in L. monocytogenes. A forward genetic screen for lysozyme-sensitive mutants led to the identification of 174 transposon insertion mutations that mapped to 13 individual genes. Four mutants were killed exclusively by lysozyme and not other cell wall-targeting molecules, including the peptidoglycan deacetylase encoded by pgdA, the putative carboxypeptidase encoded by pbpX, the orphan response regulator encoded by degU, and the highly abundant noncoding RNA encoded by rli31. Both degU and rli31 mutants had reduced expression of pbpX and pgdA, yet DegU and Rli31 did not regulate each other. Since pbpX and pgdA are also present in lysozyme-sensitive bacteria, this suggested that the acquisition of novel enzymes was not responsible for lysozyme resistance, but rather, the regulation of conserved enzymes by DegU and Rli31 conferred high lysozyme resistance. Each lysozyme-sensitive mutant exhibited attenuated virulence in mice, and a time course of infection revealed that the most lysozyme-sensitive strain was killed within 30 min of intravenous infection, a phenotype that was recapitulated in purified blood. Collectively, these data indicate that the genes required for lysozyme resistance are highly upregulated determinants of L. monocytogenes pathogenesis that are required for avoiding the enzymatic activity of lysozyme in the blood. Copyright © 2014, American Society for Microbiology. All Rights Reserved.

  1. Histochemical properties of sialic acids and antimicrobial substances in canine anal glands

    Directory of Open Access Journals (Sweden)

    T. Nara

    2011-09-01

    Full Text Available The functional properties of sialic acids appear to be manifold. Additionally, antimicrobial substances serve as a non-specific defense against microorganisms. In this study, therefore, the localization of sialic acids and antimicrobial substances in the anal glands of dog was studied by sialoglycoconjugate histochemistry and immunohistochemistry. The secretory epithelium, luminal secretions and excretory ducts exhibited high levels of sialoglycoconjugates that terminated in Siaα2-6Gal/GalNAc or Siaα2-3Gal1-4GlcNAc. Additionally, O-acetylated sialic acids were detectable in these glandular structures. Antimicrobial substances, such as lysozyme, immunoglobulin A (IgA, lactoferrin and the peptide group of β-defensins, were also demonstrated as products of the anal glands. The results obtained are discussed with regard to the functional significance of the anal glands. These secretory products may create a defensive barrier against microbial invasion at the anal mucosa.

  2. Effect of lysozyme on "flor" velum yeasts in the biological aging of sherry wines.

    Science.gov (United States)

    Roldán, Ana; Lasanta, Cristina; Caro, Ildefonso; Palacios, Víctor

    2012-05-01

    Biological aging is a key step in the production of Sherry wine classified as "fine". During this stage, a film of yeast referred to as "flor velum" covers the surface of the wine and substantially alters its characteristics. Other microorganisms may coexist with flor yeasts, such as lactic acid bacteria and non-Saccharomyces yeasts, whose growth may be favored under certain conditions, causing organoleptic deviations and deterioration of the wine. To prevent the development of lactic bacteria, lysozyme usage has been introduced. Lysozyme is a hydrolytic enzyme with muramidase activity that can lyse gram-positive bacteria; its use in winemaking was approved by the OIV in 1997 (resolution OENO 10/97). Thus far, the use of lysozyme during the production of Sherry wines is not widespread despite its effectiveness in controlling lactic acid bacteria. However, there have been no studies on the effect of lysozyme on flor velum. The aim of this study was to determine the influence of lysozyme on yeast growth and the formation, development and metabolism of flor velum during the biological aging process of Sherry wine. The results indicate that lysozyme does not affect the flor yeast during the fermentative stage or biofilm stage. However, if yeast inoculation is carried out under submerged culture conditions during biological aging, low doses of lysozyme (≥12.5 g/hL) affect cell multiplication and the membrane hydrophobicity of the yeast, inhibiting their aggregation and flotation and the subsequent development of flor velum. Thus, the yeast inoculation protocol and the methodology used for the addition of lysozyme influence velum development, its metabolism and the wine characteristics.

  3. Evaluation of alternatives for human lysozyme purification from transgenic rice: impact of phytic acid and buffer.

    Science.gov (United States)

    Wilken, Lisa R; Nikolov, Zivko L

    2010-01-01

    Producing economically competitive recombinant human lysozyme from transgenic rice demands an inexpensive purification process for nonpharmaceutical applications. Human lysozyme is a basic protein, and thus, cation exchange chromatography was the selected method for lysozyme purification. Similar to other protein production systems, the identification of critical impurities in the rice extract was important for the development of an efficient purification process. Previous adsorption data indicated that phytic acid was probably responsible for an unacceptably low cation exchange adsorption capacity. In this study, we confirm that reducing phytic acid concentration improves lysozyme binding capacity and investigate alternative process conditions that reduce phytic acid interference. Compared with the previous best process, the adsorption capacity of human lysozyme was increased from 8.6 to 19.7 mg/mL when rice extract was treated with phytase to degrade phytic acid. Using tris buffer to adjust pH 4.5 extract to pH 6 before adsorption reduced phytic acid interference by minimizing phytic acid-lysozyme interactions, eliminated the need for phytase treatment, and increased the binding capacity to 25 mg/mL. Another method of reducing phytic acid concentration was to extract human lysozyme from rice flour at pH 10 with 50 mM NaCl in 50 mM sodium carbonate buffer. A similar binding capacity (25.5 mg/mL) was achieved from pH 10 extract that was clarified by acidic precipitation and adjusted to pH 6 for adsorption. Lysozyme purities ranged from 95 to 98% for all three processing methods. The tris-mediated purification was the most efficient of the alternatives considered.

  4. Blends of zein and nylon-6

    Science.gov (United States)

    Blends of zein and nylon-6(55k)were used to produce solution cast films and electrospun fibers. Zein was blended with nylon-6 in formic acid solution. When the amount of nylon-6 was 8% or less a compatible blend formed. The blend was determined to be compatible based on physical property measurement...

  5. Forced Desorption of Bovine Serum Albumin and Lysozyme from Graphite: Insights from Molecular Dynamics Simulation.

    Science.gov (United States)

    Mücksch, Christian; Urbassek, Herbert M

    2016-08-18

    We use molecular dynamics (MD) simulation to study the adsorption and desorption of two widely different proteins, bovine serum albumin (BSA) and lysozyme, on a graphite surface. The adsorption is modeled using accelerated MD to allow the proteins to find optimum conformations on the surface. Our results demonstrate that the "hard protein" lysozyme retains much of its secondary structure during adsorption, whereas BSA loses it almost completely. BSA has a considerably larger adsorption energy compared to that of lysozyme, which does not scale with chain length. Desorption simulations are carried out using classical steered MD. The BSA molecule becomes fully unzipped during pull-off, whereas several helices survive this process in lysozyme. The unzipping process shows up in the force-distance curve of BSA as a series of peaks, whereas only a single or few, depending on protein orientation, force peaks occur for lysozyme. The maximum desorption force is larger for BSA than for lysozyme, but only by a factor of about 2.3.

  6. Amphiphilic copolymers reduce aggregation of unfolded lysozyme more effectively than polyethylene glycol

    Science.gov (United States)

    Chin, Jaemin; Mustafi, Devkumar; Poellmann, Michael J.; Lee, Raphael C.

    2017-02-01

    Certain amphiphilic block copolymers are known to prevent aggregation of unfolded proteins. To better understand the mechanism of this effect, the optical properties of heat-denatured and dithiothreitol reduced lysozyme were evaluated with respect to controls using UV–Vis spectroscopy, transmission electron microscopy (TEM) and circular dichroism (CD) measurements. Then, the effects of adding Polyethylene Glycol (8000 Da), the triblock surfactant Poloxamer 188 (P188), and the tetrablock copolymer Tetronic 1107 (T1107) to the lysozyme solution were compared. Overall, T1107 was found to be more effective than P188 in inhibiting aggregation, while PEG exhibited no efficacy. TEM imaging of heat-denatured and reduced lysozymes revealed spherical aggregates with on average 250–450 nm diameter. Using CD, more soluble lysozyme was recovered with T1107 than P188 with β-sheet secondary structure. The greater effectiveness of the larger T1107 in preventing aggregation of unfolded lysozyme than the smaller P188 and PEG points to steric hindrance at play; signifying the importance of size match between the hydrophobic region of denatured protein and that of amphiphilic copolymers. Thus, our results corroborate that certain multi-block copolymers are effective in preventing heat-induced aggregation of reduced lysozymes and future studies warrant more detailed focus on specific applications of these copolymers.

  7. The Lysozyme from Insect (Manduca sexta) is a Cold-Adapted Enzyme

    Energy Technology Data Exchange (ETDEWEB)

    Sotelo-Mundo,R.; Lopez-Zavala, A.; Garcia-Orozco, K.; Arvizu-Flores, A.; Velazquez-Contreras, E.; Valenzuela-Soto, E.; Rojo-Dominguez, A.; Kanost, M.

    2007-01-01

    Enzymatic activity is dependent on temperature, although some proteins have evolved to retain activity at low temperatures at the expense of stability. Cold adapted enzymes are present in a variety of organisms and there is ample interest in their structure-function relationships. Lysozyme (E.C. 3.2.1.17) is one of the most studied enzymes due to its antibacterial activity against Gram positive bacteria and is also a cold adapted protein. In this work the characterization of lysozyme from the insect Manduca sexta and its activity at low temperatures is presented. Both M. sexta lysozymes natural and recombinant showed a higher content of {alpha}-helix secondary structure compared to that of hen egg white lysozyme and a higher specific enzymatic activity in the range of 5-30 {sup o}C. These results together with measured thermodynamic activation parameters support the designation of M. sexta lysozyme as a cold adapted enzyme. Therefore, the insect recombinant lysozyme is feasible as a model for structure-function studies for cold-adapted proteins.

  8. Receptor-mediated endocytosis of lysozyme in renal proximal tubules of the frog Rana temporaria

    Directory of Open Access Journals (Sweden)

    E.V. Seliverstova

    2015-04-01

    Full Text Available The mechanism of protein reabsorption in the kidney of lower vertebrates remains insufficiently investigated in spite of raising interest to the amphibian and fish kidneys as a useful model for physiological and pathophysiological examinations. In the present study, we examined the renal tubular uptake and the internalization rote of lysozyme after its intravenous injection in the wintering frog Rana temporaria using immunohisto- and immunocytochemistry and specific markers for some endocytic compartments. The distinct expression of megalin and cubilin in the proximal tubule cells of lysozyme-injected frogs was revealed whereas kidney tissue of control animals showed no positive immunoreactivity. Lysozyme was detected in the apical endocytic compartment of the tubular cells and colocalized with clathrin 10 min after injection. After 20 min, lysozyme was located in the subapical compartment negative to clathrin (endosomes, and intracellular trafficking of lysozyme was coincided with the distribution of megalin and cubilin. However, internalized protein was retained in the endosomes and did not reach lysosomes within 30 min after treatment that may indicate the inhibition of intracellular trafficking in hibernating frogs. For the first time, we provided the evidence that lysozyme is filtered through the glomeruli and absorbed by receptor-mediated clathrin-dependent endocytosis in the frog proximal tubule cells. Thus, the protein uptake in the amphibian mesonephros is mediated by megalin and cubilin that confirms a critical role of endocytic receptors in the renal reabsorption of proteins in amphibians as in mammals.

  9. Effect of Fe{sub 3}O{sub 4} magnetic nanoparticles on lysozyme amyloid aggregation

    Energy Technology Data Exchange (ETDEWEB)

    Bellova, Andrea; Koneracka, Martina; Kopcansky, Peter; Tomasovicova, Natalia; Timko, Milan; Bagelova, Jaroslava; Gazova, Zuzana [Department of Biophysics, Department of Magnetism, Institute of Experimental Physics, Slovak Academy of Science, Watsonova 47, 04001 Kosice (Slovakia); Bystrenova, Eva; Valle, Francesco; Biscarini, Fabio, E-mail: gazova@saske.sk [CNR-Instituto per lo Studio dei Materiali Nanostrutturati, via Gobetti 101, I-40129 Bologna (Italy)

    2010-02-10

    Peptide amyloid aggregation is a hallmark of several human pathologies termed amyloid diseases. We have investigated the effect of electrostatically stabilized magnetic nanoparticles of Fe{sub 3}O{sub 4} on the amyloid aggregation of lysozyme, as a prototypical amyloidogenic protein. Thioflavin T fluorescence assay and atomic force microscopy were used for monitoring the inhibiting and disassembly activity of magnetic nanoparticles of Fe{sub 3}O{sub 4}. We have found that magnetic Fe{sub 3}O{sub 4} nanoparticles are able to interact with lysozyme amyloids in vitro leading to a reduction of the amyloid aggregates, thus promoting depolymerization; the studied nanoparticles also inhibit lysozyme amyloid aggregation. The ability to inhibit lysozyme amyloid formation and promote lysozyme amyloid disassembly exhibit concentration-dependent characteristics with IC50 = 0.65 mg ml{sup -1} and DC50 = 0.16 mg ml{sup -1} indicating that nanoparticles interfere with lysozyme aggregation already at stoichiometric concentrations. These features make Fe{sub 3}O{sub 4} nanoparticles of potential interest as therapeutic agents against amyloid diseases and their non-risk exploitation in nanomedicine and nanodiagnostics.

  10. Isolation and characterization of a c-type lysozyme from the nurse shark.

    Science.gov (United States)

    Hinds Vaughan, Nichole; Smith, Sylvia L

    2013-12-01

    Lysozyme is a ubiquitous antibacterial enzyme that occurs in numerous invertebrate and vertebrate species. Three forms have been described c-type, g-type and i-type which differ in primary structure. Shark lysozyme has not been characterized; here we report on the isolation and characterization of lysozyme from unstimulated shark (Ginglymostoma cirratum) leukocytes and provide amino acid sequence data across the highly conserved active site of the molecule identifying it to be a c-type lysozyme. A leukocyte lysate was applied either (a) to the first of two sequential DE-52 cellulose columns or alternatively, (b) to a DEAE-Sepharose column. Lysozyme activity in lysate and active fractions was identified by zones of lysis of Micrococcus lysodeikticus cell walls on lysoplates and zones of growth inhibition in agar diffusion assays using Planococcus citreus as the target organism. SDS-PAGE analysis revealed a 14 kDa protein which was identified as lysozyme by mass spectroscopic analysis of peptides, reactivity against anti-HEWL antibodies on a Western blot, hydrolysis of M. lysodeikticus cell walls, and inhibition of growth of P. citreus on AU-gel blots in which the area of growth inhibition correlated to a 14 kDa protein.

  11. Binding of copper to lysozyme: Spectroscopic, isothermal titration calorimetry and molecular docking studies

    Science.gov (United States)

    Jing, Mingyang; Song, Wei; Liu, Rutao

    2016-07-01

    Although copper is essential to all living organisms, its potential toxicity to human health have aroused wide concerns. Previous studies have reported copper could alter physical properties of lysozyme. The direct binding of copper with lysozyme might induce the conformational and functional changes of lysozyme and then influence the body's resistance to bacterial attack. To better understand the potential toxicity and toxic mechanisms of copper, the interaction of copper with lysozyme was investigated by biophysical methods including multi-spectroscopic measurements, isothermal titration calorimetry (ITC), molecular docking study and enzyme activity assay. Multi-spectroscopic measurements proved that copper quenched the intrinsic fluorescence of lysozyme in a static process accompanied by complex formation and conformational changes. The ITC results indicated that the binding interaction was a spontaneous process with approximately three thermodynamical binding sites at 298 K and the hydrophobic force is the predominant driven force. The enzyme activity was obviously inhibited by the addition of copper with catalytic residues Glu 35 and Asp 52 locating at the binding sites. This study helps to elucidate the molecular mechanism of the interaction between copper and lysozyme and provides reference for toxicological studies of copper.

  12. Polyamide blend-based nanocomposites: A review

    Directory of Open Access Journals (Sweden)

    W. S. Chow

    2015-03-01

    Full Text Available Polymer blend nanocomposites have been considered as a stimulating route for creating a new type of high performance material that combines the advantages of polymer blends and the merits of polymer nanocomposites. In nanocomposites with multiphase matrices, the concept of using nanofillers to improve select properties (e.g., mechanical, thermal, chemical, etc of a polymer blend, as well as to modify and stabilize the blend morphology has received a great deal of interest. This review reports recent advances in the field of polyamide (PA blend-based nanocomposites. Emphasis is placed on the PA-rich blends produced by blending with other thermoplastics in the presence of nanofillers. The processing and properties of PA blend-based nanocomposites with nanofillers are discussed. In addition, the mechanical properties and morphology changes of PA blends with the incorporation of nanofillers are described. The issues of compatibility and toughening of PA blend nanocomposites are discussed, and current challenges are highlighted.

  13. Blended Learning: The Student Viewpoint

    African Journals Online (AJOL)

    learning and development to the needs of individuals by integrating the innovative and .... Learners represent different generations, different personality types, and different .... learning, social presence and satisfaction in a blended learning.

  14. Blended Learning: The Student Viewpoint

    African Journals Online (AJOL)

    ... the needs of students who are not in a position to attend traditional contact classes ... Keywords: Blended learning, Online learning, Students' perceptions. Access this ... lecture time. Online .... The BL content encouraged me to learn. ‑. 4. 9.3.

  15. Maternal lysozyme concentrations in the eggs of the Great Cormorant (Phalacrocorax carbo) in relation to breeding density and laying order

    Institute of Scientific and Technical Information of China (English)

    Jian Cao; Jirong Li; Wen Wang; Fang Yang; Zhuo Li; Laixing Li

    2015-01-01

    Background: Females can differentially deposit the immune factor lysozyme into eggs based on conditions of local breeding density and laying order.Materials: We collected 80 eggs from Great Cormorants(Phalacrocorax carbo) and then analyzed whether the level of lysozymes in the eggs is related to breeding density and laying order.Results: Between clutches,the level of lysozyme in eggs is positively related to breeding density; while within a clutch,the level of lysozyme is positively related to the laying order.Conclusion: When parents breed under conditions of high density,they allocate more lysozymes to their offspring,a trait adaptive to the local environment.That the increase in the level of lysozymes is a function of the laying order seems a necessary condition to mitigate the hierarchy among siblings for improving the survival of the entire clutch.

  16. Blended Learning in der Wirtschaftsinformatik

    OpenAIRE

    Gabriel, Roland; Weber, Peter

    2011-01-01

    Der vorliegende Projektbericht stellt das Blended Learning-Konzept und insbesondere ein darin enthaltenes Sonderpunkteprogramm zweier Vorlesungen vor, die auf dem RuhrCampusOnline der drei Ruhrgebietsuniversitäten angeboten werden. Der Artikel entwickelt sich dabei vom Allgemeinen zum Speziellen: Nach einer Erläuterung der Rahmenbedingungen in Form des RuhrCampusOnline und des Lehrmoduls „Management & Information“ wird zunächst das Blended Learning-Konzept der Lehrveranstaltungen vorgestellt....

  17. An Investigation into the Physico-chemical Properties of Transformer Oil Blends with Antioxidants extracted from Turmeric Powder

    Science.gov (United States)

    Dukhi, Veresha; Bissessur, Ajay; Ngila, Catherine Jane; Ijumba, Nelson Mutatina

    2013-07-01

    The blending of transformer oil (used mainly as an insulating oil) with appropriate synthetic antioxidants, such as BHT (2,6-di-tert-butyl-4-methylphenol) and DBP (2,6-di-tert-butylphenol) have been previously reported. This article is focused on the use of antioxidant extracts from turmeric (Curcuma longa), a natural source. Turmeric is well known for its antimicrobial, antioxidant and anticarcinogenic properties owing to the active nature of its components. Extracts from powdered turmeric were subsequently blended into naphthenic-based uninhibited virgin transformer oil, hereinafter referred to as extract-oil blends (E-OB). Thin-layer chromatography (TLC) of the oil blends revealed that five components extracted from turmeric powder were successfully blended into the oil. Subsequent gas chromatography-mass spectrometry (GC-MS) analysis confirmed the presence of the compounds: curcumene, sesquiphellandrene, ar-turmerone, turmerone and curlone. Thermogravimetric analysis (TGA) of the extract-oil blends, containing various levels of extracts, revealed an average temperature shift of ˜8.21°C in the initial onset of degradation in comparison to virgin non-blended oil. The 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay showed that an increase in the mass aliquot of turmeric extracts in the transformer oil increased the free radical scavenging activity of the oil. Electrical properties of the oil investigated showed that the dissipation factor in the blended oil was found to be lower than that of virgin transformer oil. Evidently, a lower dissipation value renders the oil blend as a superior insulator over normal virgin non-blended oil. This investigation elucidated improved physico-chemical properties of transformer oil blended with turmeric antioxidant extracts.

  18. Anti-antimicrobial Peptides

    Science.gov (United States)

    Ryan, Lloyd; Lamarre, Baptiste; Diu, Ting; Ravi, Jascindra; Judge, Peter J.; Temple, Adam; Carr, Matthew; Cerasoli, Eleonora; Su, Bo; Jenkinson, Howard F.; Martyna, Glenn; Crain, Jason; Watts, Anthony; Ryadnov, Maxim G.

    2013-01-01

    Antimicrobial or host defense peptides are innate immune regulators found in all multicellular organisms. Many of them fold into membrane-bound α-helices and function by causing cell wall disruption in microorganisms. Herein we probe the possibility and functional implications of antimicrobial antagonism mediated by complementary coiled-coil interactions between antimicrobial peptides and de novo designed antagonists: anti-antimicrobial peptides. Using sequences from native helical families such as cathelicidins, cecropins, and magainins we demonstrate that designed antagonists can co-fold with antimicrobial peptides into functionally inert helical oligomers. The properties and function of the resulting assemblies were studied in solution, membrane environments, and in bacterial culture by a combination of chiroptical and solid-state NMR spectroscopies, microscopy, bioassays, and molecular dynamics simulations. The findings offer a molecular rationale for anti-antimicrobial responses with potential implications for antimicrobial resistance. PMID:23737519

  19. [Antimicrobial prophylaxis in surgery].

    Science.gov (United States)

    Cisneros, José Miguel; Rodríguez-Baño, Jesús; Mensa, José; Trilla, Antoni; Cainzos, Miguel

    2002-01-01

    Antimicrobial prophylaxis in surgery refers to a very brief course of an antimicrobial agent initiated just before the start of the procedure. The efficacy of antimicrobials to prevent postoperative infection at the site of surgery (incisional superficial, incisional deep, or organ/space infection) has been demonstrated for many surgical procedures. Nevertheless, the majority of studies centering on the quality of preoperative prophylaxis have found that a high percentage of the antimicrobials used are inappropriate for this purpose. This work discusses the scientific basis for antimicrobial prophylaxis, provides general recommendations for its correct use and specific recommendations for various types of surgery. The guidelines for surgical antimicrobial prophylaxis are based on results from well-designed studies, whenever possible. These guidelines are focussed on reducing the incidence of infection at the surgical site while minimizing the contribution of preoperative administration of antimicrobials to the development of bacterial resistance.

  20. Fabrication of High-Performance Magnetic Lysozyme-Imprinted Microsphere and Its NIR-Responsive Controlled Release Property.

    Science.gov (United States)

    Chen, Jinxing; Lei, Shan; Xie, Yunyun; Wang, Mozhen; Yang, Jun; Ge, Xuewu

    2015-12-30

    The preparation of efficient and practical biomacromolecules imprinted polymer materials is still a challenging task because of the spatial hindrance caused by the large size of template and target molecules in the imprinting and recognition process. Herein, we provided a novel pathway to coat a NIR-light responsive lysozyme-imprinted polydopamine (PDA) layer on a fibrous SiO2 (F-SiO2) microsphere grown up from a magnetic Fe3O4 core nanoparticle. The magnetic core-shell structured lysozyme-imprinted Fe3O4@F-SiO2@PDA microspheres (MIP-lysozyme) can be easily separated by a magnet and have a high saturation adsorption capacity of lysozyme of 700 mg/g within 30 min because of the high surface area of 570 m(2)/g and the mesopore size of 12 nm of the Fe3O4@F-SiO2 support. The MIP-lysozyme microspheres also show an excellent selective adsorption of lysozyme (IF > 4). The binding thermodynamic parameters studied by ITC proves that the lysozyme should be restricted by the well-defined 3D structure of MIP-lysozyme microspheres. The MIP-lysozyme can extract lysozyme efficiently from real egg white. Owing to the efficient NIR light photothermal effect of PDA layer, the MIP-lysozyme microspheres show the controlled release property triggered by NIR laser. The released lysozyme molecules still maintain good bioactivity, which can efficiently decompose E. coli. Therefore, this work provides a novel strategy to build practical NIR-light-responsive MIPs for the extraction and application of biomacromolecules.

  1. Synthesis and characterization of chitosan/curcumin blends based polyurethanes.

    Science.gov (United States)

    Zia, Fatima; Zia, Khalid Mahmood; Zuber, Mohammad; Rehman, Saima; Tabasum, Shazia; Sultana, Salma

    2016-11-01

    In this work, new hexamethylene diisocyanate (HMDI) and hyroxylterminated polybutadiene (HTPB) based polyurethanes (PUs) were prepared following step growth polymerization by the introduction of varying mole ratio of chitosan (CH) and curcumin (CUR). Structural study of blends through infrared spectroscopy confirmed the incorporation of CH and CUR into the backbone of the PU. The scanning electron microscopic (SEM) study confirmed the well dispersion of incorporated chitosan/curcumin and homogeneity of surface of synthesized samples. Thermogravimetric analysis (TGA) of PU blends indicated a better thermal stability with 0.25M:0.75M of chitosan to curcumin. Mechanical properties such as modulus and tensile strength of PU blends were found to be better with higher contents of chitosan and curcumin. The same extender composition (1mol BDO, 075mol chitosan and 0.25mol curcumin) based PU showed higher substantial of antimicrobial activity as compared to the all other PUs. On the whole, this work is actually a step towards the generation of novel biocompatible materials preferably useful for biomedical applications. Copyright © 2016 Elsevier B.V. All rights reserved.

  2. Interaction mechanism between berberine and the enzyme lysozyme

    Science.gov (United States)

    Cheng, Ling-Li; Wang, Mei; Wu, Ming-Hong; Yao, Si-De; Jiao, Zheng; Wang, Shi-Long

    2012-11-01

    In the present paper, the interaction between model protein lysozyme (Lys) and antitumorigenic berberine (BBR) was investigated by spectroscopic methods, for finding an efficient and safe photosensitizer with highly active transient products using in photodynamic therapy study. The fluorescence data shows that the binding of BBR could change the environment of the tryptophan (Trp) residues of Lys, and form a new complex. Static quenching is the main fluorescence quenching mechanism between Lys and BBR, and there is one binding site in Lys for BBR and the type of binding force between them was determined to be hydrophobic interaction. Furthermore, the possible interaction mechanism between BBR and Lys under the photoexcitation was studied by laser flash photolysis method, the results demonstrated that BBR neutral radicals (BBR(-H)•) react with Trp (K = 3.4 × 109 M-1 s-1) via electron transfer to give the radical cation (Trp/NH•+) and neutral radical of Trp (TrpN•). Additionally BBR selectively oxidize the Trp residues of Lys was also observed by comparing the transient absorption spectra of their reaction products. Through thermodynamic calculation, the reaction mechanisms between 3BBR∗ and Trp or Lys were determined to be electron transfer process.

  3. Exercise increases lactoferrin, but decreases lysozyme in salivary granulocytes.

    Science.gov (United States)

    Gillum, Trevor; Kuennen, Matthew; McKenna, Zachary; Castillo, Micaela; Jordan-Patterson, Alex; Bohnert, Caitlin

    2017-05-01

    Intracellular lactoferrin (Lac) and lysozyme (Lys) content play an important role in regulating inflammation and promoting host protection. While exercise has demonstrated an increase in Lac and Lys concentration in exocrine solutions, little is known regarding intracellular concentration changes in response to exercise. To quantify intracellular Lac and Lys concentration before and after exercise in salivary CD45(+)CD15(+) cells. 11 males (20.3 ± 0.8 years, 57.2 ± 7.6 mL/kg/min V̇O2pk, 11.1 ± 3.9% body fat) ran for 45 min at 75% of VO2pk. 12 mL of stimulated saliva were collected pre and immediately post exercise. Saliva was filtered through a 30-µm filter before analysis of leukocytes (CD45(+)) and granulocytes (CD45(+)CD15(+)) using flow cytometry. Median fluorescent intensity (MFI) of Lac increased from pre (64,268 ± 46,036 MFI) to post (117,134 ± 88,115 MFI) exercise (p exercise (pre: 16,933 ± 8249; post: 11,616 ± 6875) (p exercise. Conversely, the exercise-associated decrease of intracellular Lys content could be the cause of increased Lys in exocrine solutions.

  4. [Generation of transgenic mice expressing human lysozyme in mammary gland].

    Science.gov (United States)

    Yan, Hua; Li, Guo-cai; Sun, Huai-chang

    2005-10-01

    To evaluate the feasibility of generating animal mammary gland bioreactors expressing human lysozyme (hLYZ). The recombinant vector p205C3-hLYZ, as a result of connecting the hLYZ cDNA with the mammry gland expression vector p205C3, was used to generate transfer genic mice by microinjection. A total of 136 F0 mice were obtained, of which 7 (2 females and 5 males) and 4 (1 females and 3 males) were found to contain the transfer-gene by PCR and Southern blotting respectively. The results of Western blotting indicated that the expressed protein had the same molecular weight as that of normal hLYZ. From the F1 generation on, the mice mated only with their brothers or sisters and a colony of F7 transgenic mice was obtained. Among the offspring, the female transgenic mice maintained and expressed the transfer-gene stably with an expression level as high as 750 mg/L. The expressed protein had strong tissue specificity, and in addition to the mammary glands, some degree of ectropic expression in the spleens and intestines of the transgenic mice was confirmed by dot blotting assay. These data indicate that the mice mammary gland bioreactors expressing hLYZ have been successfully generated.

  5. Crystallization of Chicken Egg-White Lysozyme from Ammonium Sulfate

    Science.gov (United States)

    Forsythe, Elizabeth L.; Snell, Edward H.; Pusey, Marc L.

    1997-01-01

    Chicken egg-white lysozyme was crystallized from ammonium sulfate over the pH range 4.0-7.8, with protein concentrations from 100 to 150 mg/ml. Crystals were obtained by vapor-diffusion or batch-crystallization methods. The protein crystallized in two morphologies with an apparent morphology dependence on temperature and protein concentration. In general, tetragonal crystals could be grown by lowering the protein concentration or temperature. Increasing the temperature or protein concentration resulted in the growth of orthorhombic crystals. Representative crystals of each morphology were selected for X-ray analysis. The tetragonal crystals belonged to the P4(sub 3)2(sub 1)2 space group with crystals grown at ph 4.4 having unit-cell dimensions of a = b = 78.7 1, c=38.6 A and diffracting to beyond 2.0 A. The orthorhombic crystals, grown at pH 4.8, were of space group P2(sub 1)2(sub 1)2 and had unit-cell dimensions of a = 30.51, b = 56.51 and c = 73.62 A.

  6. Elastic constants in orthorhombic hen egg-white lysozyme crystals.

    Science.gov (United States)

    Kitajima, N; Tsukashima, S; Fujii, D; Tachibana, M; Koizumi, H; Wako, K; Kojima, K

    2014-01-01

    The ultrasonic sound velocities of cross-linked orthorhombic hen egg-white lysozyme (HEWL) crystals, including a large amount of water in the crystal, were measured using an ultrasonic pulse-echo method. As a result, seven elastic constants of orthorhombic crystals were observed to be C11 = 5.24 GPa, C22 = 4.87 GPa, C12 = 4.02 GPa, C33 = 5.23 GPa, C44 = 0.30 GPa, C55 = 0.40 GPa, and C66 = 0.43 GPa, respectively. However, C13 and C23 could not be observed because the suitable crystal planes could not be cut from bulk crystals. We conclude that the observed elastic constants of the cross-linked crystals are coincident with those of the intrinsic crystals without cross-linking. Moreover, the characteristics of the elastic constants in orthorhombic HEWL crystals are due to the fact that the shear elastic constants, C44, C55, and C66, are softer than in tetragonal crystals. That is, the shear components, C44, C55, and C66, are one half of those of the tetragonal crystals.

  7. The impact of a 24-h ultra-marathon on salivary antimicrobial protein responses.

    Science.gov (United States)

    Gill, S K; Teixeira, A M; Rosado, F; Hankey, J; Wright, A; Marczak, S; Murray, A; Costa, R J S

    2014-10-01

    Depressed oral respiratory mucosal immunity and increased incidence of upper respiratory symptoms are commonly reported after bouts of prolonged exercise. The current study observed the impact of a 24-h continuous overnight ultra-marathon competition (distance range: 122-208 km; ambient temperature range: 0-20 °C) on salivary antimicrobial protein responses and incidence of upper respiratory symptoms. Body mass, unstimulated saliva and venous blood samples were taken from ultra-endurance runners (n=25) and controls (n=17), before and immediately after competition. Upper respiratory symptoms were assessed during and until 4-weeks after event completion. Samples were analyzed for salivary IgA, lysozyme, α-amylase and cortisol in addition to plasma osmolality. Decreased saliva flow rate (p<0.001), salivary IgA (p<0.001) and lysozyme (p=0.015) secretion rates, and increased salivary α-amylase secretion rate (p<0.001) and cortisol responses (p<0.001) were observed post-competition in runners, with no changes being observed in controls. No incidences of upper respiratory symptoms were reported by participants. A 24-h continuous overnight ultra-marathon resulted in the depression of some salivary antimicrobial protein responses, but no incidences of upper respiratory symptoms were evident during or following competition. Salivary antimicrobial protein synergism, effective management of non-infectious episodes, maintaining euhydration, and (or) favourable environmental influences could have accounted for the low prevalence of upper respiratory symptoms.

  8. High performance aptamer affinity chromatography for single-step selective extraction and screening of basic protein lysozyme.

    Science.gov (United States)

    Han, Bin; Zhao, Chao; Yin, Junfa; Wang, Hailin

    2012-08-15

    A DNA aptamer based high-performance affinity chromatography is developed for selective extraction and screening of a basic protein lysozyme. First, a poly(glycidyl methacrylate-co-ethylene dimethacrylate) monolithic column was synthesized in situ by thermally initiated radical polymerization, and then an anti-lysozyme DNA aptamer was covalently immobilized on the surface of the monolith through a 16-atom spacer arm. The target protein lysozyme but non-target proteins can be trapped by the immobilized anti-lysozyme DNA aptamer. In contrast, lysozyme cannot be trapped by the immobilized oligodeoxynucleotide that does not contain the sequence of the anti-lysozyme DNA aptamer. The study clearly demonstrates the trapping of lysozyme by the immobilized anti-lysozyme DNA aptamer is mainly due to specific recognition rather than simple electrostatic interaction of positively charged protein and the negatively charged DNA. The inter-day precision was determined as 0.8% for migration time and 4.2% for peak area, respectively. By the use of aptamer affinity monolith, a screening strategy is developed to selectively extract lysozyme from chicken egg white, showing the advantages of high efficiency, low cost and ease-of-operation.

  9. cDNA cloning, expression and antibacterial activity of lysozyme C in the blue shrimp (Litopenaeus stylirostris)

    Institute of Scientific and Technical Information of China (English)

    Weijun Mai; Chaoqun Hu

    2009-01-01

    The gene coding for lysozyme in blue shrimp (Litopenaeus stylirostris) was cloned, sequenced and expressed in pET-32a vector. The deduced amino acid sequence of F. Merguiensi lysozyme showed 37-93% similarity with the mouse, human, chicken, and tiger prawn counterparts. The lysozyme was purified to homogeneity and observed as a band of approximately 15 kDa in 15% SDS-PAGE. Semi-quantitative RT-PCR analysis demonstrated that mRNA transcripts of lysozyme could be mainly detected in the tissues of haemocytes, gill, gonad and the lymphoid organ of unchallenged shrimps, whereas the expression of lysozyme transcripts was increased in all the tested tissues after the heat-killed Vibrio alginolyticus challenge. The temporal expression of lysozyme mRNA in haemolymph challenged by Micrococcus luteus and V. Alginolyticus was both up-regulated and reached the maximum level at 8 and 16 h post-stimulation, respec-tively, and then dropped back to the original level. Bacteriolytic activity of the lysozyme against different bacterial cultures was deter-mined by the solid phase and turbidimetric assays. The results demonstrated that the lysozyme we obtained was not only against Gram-positive and Gram-negative bacteria but also against shrimp pathogens V. Alginolyticus and V. Parahemolyticus. In addition, the study of the inhibition mechanism revealed that the antibacterial activity of the lysozyme was a result of the bactericidal effect.

  10. Wavelet and Blend maps for texture synthesis

    Directory of Open Access Journals (Sweden)

    Du Jin-Lian

    2011-04-01

    Full Text Available blending is now a popular technology for large realtime texture synthesis .Nevertheless, creating blend map during rendering is time and computation consuming work. In this paper, we exploited a method to create a kind of blend tile which can be tile together seamlessly. Note that blend map is in fact a kind of image, which is Markov Random Field, contains multiresolution signals, while wavelet is a powerful way to process multiresolution signals, we use wavelet to process the traditional blend tile. After our processing steps, the result blend tile become smooth and suitable for tiling, with no important features lost. Using this kind blend tile, many computation resources for computing blend map during texture synthesizing is saved. The experimental results shows that our method may successfully process many traditional blend tiles.

  11. Performance of Blended Learning in University Teaching:

    Directory of Open Access Journals (Sweden)

    Michael Reiss

    2010-07-01

    Full Text Available Blended learning as a combination of classroom teaching and e-learning has become a widely represented standard in employee and management development of companies. The exploratory survey “Blended Learning@University” conducted in 2008 investigated the integration of blended learning in higher education. The results of the survey show that the majority of participating academic teachers use blended learning in single courses, but not as a program of study and thus do not exploit the core performance potential of blended learning. According to the study, the main driver of blended learning performance is its embeddedness in higher education. Integrated blended programs of study deliver the best results. In blended learning, learning infrastructure (in terms of software, culture, skills, funding, content providing, etc. does not play the role of a performance driver but serves as an enabler for blended learning.

  12. Lysozyme stability and amyloid fibrillization dependence on Hofmeister anions in acidic pH.

    Science.gov (United States)

    Poniková, Slavomíra; Antošová, Andrea; Demjén, Erna; Sedláková, Dagmar; Marek, Jozef; Varhač, Rastislav; Gažová, Zuzana; Sedlák, Erik

    2015-09-01

    We have explored an effect of Hofmeister anions, Na2SO4, NaCl, NaBr, NaNO3, NaSCN and NaClO4, on stability and amyloid fibrillization of hen egg white lysozyme at pH 2.7. The stability of the protein was analyzed by differential scanning calorimetry. The Hofmeister effect of the anions was assessed by the parameter dT trs/d[anion] (T trs, transition temperature). We show that dT trs/d[anion] correlates with anion surface tension effects and anion partition coefficients indicating direct interactions between anions and lysozyme. The kinetic of amyloid fibrillization of lysozyme was followed by Thioflavin T (ThT) fluorescence. Negative correlation between dT trs/d[anion] and the nucleation rate of fibrillization in the presence of monovalent anions indicates specific effect of anions on fibrillization rate of lysozyme. The efficiency of monovalent anions to accelerate fibrillization correlates with inverse Hofmeister series. The far-UV circular dichroism spectroscopy and atomic force microscopy findings show that conformational properties of fibrils depend on fibrillization rate. In the presence of sodium chloride, lysozyme forms typical fibrils with elongated structure and with the secondary structure of the β-sheet. On the other hand, in the presence of both chaotropic perchlorate and kosmotropic sulfate anions, the fibrils form clusters with secondary structure of β-turn. Moreover, the acceleration of fibril formation is accompanied by decreased amount of the formed fibrils as indicated by ThT fluorescence. Taken together, our study shows Hofmeister effect of monovalent anions on: (1) lysozyme stability; (2) ability to accelerate nucleation phase of lysozyme fibrillization; (3) amount, and (4) conformational properties of the formed fibrils.

  13. Molecular Cloning and Characterization of a New C-type Lysozyme Gene from Yak Mammary Tissue

    Directory of Open Access Journals (Sweden)

    Ming Feng Jiang

    2015-12-01

    Full Text Available Milk lysozyme is the ubiquitous enzyme in milk of mammals. In this study, the cDNA sequence of a new chicken-type (c-type milk lysozyme gene (YML, was cloned from yak mammary gland tissue. A 444 bp open reading frames, which encodes 148 amino acids (16.54 kDa with a signal peptide of 18 amino acids, was sequenced. Further analysis indicated that the nucleic acid and amino acid sequences identities between yak and cow milk lysozyme were 89.04% and 80.41%, respectively. Recombinant yak milk lysozyme (rYML was produced by Escherichia coli BL21 and Pichia pastoris X33. The highest lysozyme activity was detected for heterologous protein rYML5 (M = 1,864.24 U/mg, SD = 25.75 which was expressed in P. pastoris with expression vector pPICZαA and it clearly inhibited growth of Staphylococcus aureus. Result of the YML gene expression using quantitative polymerase chain reaction showed that the YML gene was up-regulated to maximum at 30 day postpartum, that is, comparatively high YML can be found in initial milk production. The phylogenetic tree indicated that the amino acid sequence was similar to cow kidney lysozyme, which implied that the YML may have diverged from a different ancestor gene such as cow mammary glands. In our study, we suggest that YML be a new c-type lysozyme expressed in yak mammary glands that plays a role as host immunity.

  14. Hexafluoroisopropanol-induced catanionic-surfactants-based coacervate extraction for analysis of lysozyme.

    Science.gov (United States)

    Xu, Jia; Niu, Manli; Xiao, Yuxiu

    2017-02-01

    A coacervate extraction method, based on hexafluoroisopropanol (HFIP)-induced catanionic surfactants and coupled with a back-extraction procedure, was developed for separation and purification of proteins, using sodium dodecyl sulfate (SDS) and dodecyltrimethyl ammonium bromide (DTAB) as representative catanionic surfactants and lysozyme as a model protein. After the coacervate extraction and back extraction, the obtained lysozyme solutions were examined in terms of quantitative analysis by capillary electrophoresis, bacteriolytic activity, and circular dichroism (CD). The effects of several parameters including back-extraction solvent, HFIP content, total surfactant concentration, and SDS/DTAB molar ratio were investigated in detail on the extraction efficiency and activity of lysozyme. Under the optimized extraction conditions (66 mM KH2PO4 buffer with pH 6.2 as back-extraction solvent, SDS/DTAB molar ratio = 1:1 mol/mol, total surfactant concentration = 30 mM, HIFP concentration = 8 % v/v), the extraction recovery was 89.8 % (±4.7, n = 3), limit of detection was 2.2 (±0.3, n = 3) μg mL(-1), and meanwhile nearly 65 % of native lysozyme activity was retained. In addition, the activity and CD assays showed that SDS/DTAB molar ratio had a significant influence on the activity and structure of lysozyme after extraction. The DTAB-rich extraction systems, in which the DTAB mole fraction was equal to or larger than 70 %, could keep the activity and structure of lysozyme almost in the native state. Graphical Abstract Procedure of HFIP-induced SDS/DTAB coacervate extraction and back extraction of lysozyme.

  15. Synthesis of hydrophobic nanoparticles for real-time lysozyme detection using surface plasmon resonance sensor.

    Science.gov (United States)

    Saylan, Yeşeren; Yılmaz, Fatma; Derazshamshir, Ali; Yılmaz, Erkut; Denizli, Adil

    2017-03-21

    Diagnostic biomarkers such as proteins and enzymes are generally hard to detect because of the low abundance in biological fluids. To solve this problem, the advantages of surface plasmon resonance (SPR) and nanomaterial technologies have been combined. The SPR sensors are easy to prepare, no requirement of labelling and can be detected in real time. In addition, they have high specificity and sensitivity with low cost. The nanomaterials have also crucial functions such as efficiency improvement, selectivity, and sensitivity of the detection systems. In this report, an SPR-based sensor is developed to detect lysozyme with hydrophobic poly (N-methacryloyl-(L)-phenylalanine) (PMAPA) nanoparticles. The SPR sensor was first characterized by attenuated total reflection-Fourier transform infrared, atomic force microscope, and water contact angle measurements and performed with aqueous lysozyme solutions. Various concentrations of lysozyme solution were used to calculate kinetic and affinity coefficients. The equilibrium and adsorption isotherm models of interactions between lysozyme solutions and SPR sensor were determined and the maximum reflection, association, and dissociation constants were calculated by Langmuir model as 4.87, 0.019 nM(-1) , and 54 nM, respectively. The selectivity studies of SPR sensor were investigated with competitive agents, hemoglobin, and myoglobin. Also, the SPR sensor was used four times in adsorption/desorption/recovery cycles and results showed that, the combination of optical SPR sensor with hydrophobic ionizable PMAPA nanoparticles in one mode enabled the detection of lysozyme molecule with high accuracy, good sensivity, real-time, label-free, and a low-detection limit of 0.66 nM from lysozyme solutions. Lysozyme detection in a real sample was performed by using chicken egg white to evaluate interfering molecules present in the medium.

  16. Inhibition of lysozyme amyloidogenesis by phospholipids. Focus on long-chain dimyristoylphosphocholine.

    Science.gov (United States)

    Ponikova, Slavomira; Kubackova, Jana; Bednarikova, Zuzana; Marek, Jozef; Demjen, Erna; Antosova, Andrea; Musatov, Andrey; Gazova, Zuzana

    2017-11-01

    Protein amyloid aggregation is an important pathological feature of a group of different degenerative human diseases called amyloidosis. We tested effect of two phospholipids, 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) and 1,2-dihexanoyl-sn-glycero-3-phosphocholine (DHPC) on amyloid aggregation of hen egg white (HEW) lysozyme in vitro. Effect of phospholipids was investigated using spectroscopic techniques (fluorescence and CD spectroscopy), atomic force microscopy and image analysis. Phospholipids DMPC and DHPC are able dose-dependently inhibit lysozyme fibril formation. The length of the phospholipid tails and different structural arrangement of the phospholipid molecules affect inhibitory activity; long-chain DMPC inhibits fibrillization more efficiently. Interestingly, interference of DMPC with lysozyme amyloid fibrils has no effect on their morphology or amount. Phospholipid molecules have significant effect on lysozyme amyloid fibrillization. We suggest that inhibitory activity is due to the interference of phospholipids with lysozyme leading to the blocking of the intermolecular protein interactions important for formation of the cross-β structure within the core of the fibrils. The higher inhibitory activity of DMPC is probably due to adsorption of protein molecules on the liposome surfaces which caused decrease of species needed for fibrillization. Interaction of the phospholipids with formed fibrils is not sufficient enough to interrupt the bonds in β-sheets which are required for destroying of amyloid fibrils. The obtained results contribute to a better understanding of the effect of phospholipids on amyloid fibrillization of the lysozyme. The data suggest that DMPC and DHPC phospholipids represent agents able to modulate lysozyme amyloid aggregation. Copyright © 2017 Elsevier B.V. All rights reserved.

  17. Commercial Essential Oils as Potential Antimicrobials to Treat Skin Diseases

    Directory of Open Access Journals (Sweden)

    Ané Orchard

    2017-01-01

    Full Text Available Essential oils are one of the most notorious natural products used for medical purposes. Combined with their popular use in dermatology, their availability, and the development of antimicrobial resistance, commercial essential oils are often an option for therapy. At least 90 essential oils can be identified as being recommended for dermatological use, with at least 1500 combinations. This review explores the fundamental knowledge available on the antimicrobial properties against pathogens responsible for dermatological infections and compares the scientific evidence to what is recommended for use in common layman’s literature. Also included is a review of combinations with other essential oils and antimicrobials. The minimum inhibitory concentration dilution method is the preferred means of determining antimicrobial activity. While dermatological skin pathogens such as Staphylococcus aureus have been well studied, other pathogens such as Streptococcus pyogenes, Propionibacterium acnes, Haemophilus influenzae, and Brevibacterium species have been sorely neglected. Combination studies incorporating oil blends, as well as interactions with conventional antimicrobials, have shown that mostly synergy is reported. Very few viral studies of relevance to the skin have been made. Encouragement is made for further research into essential oil combinations with other essential oils, antimicrobials, and carrier oils.

  18. Commercial Essential Oils as Potential Antimicrobials to Treat Skin Diseases

    Science.gov (United States)

    Orchard, Ané

    2017-01-01

    Essential oils are one of the most notorious natural products used for medical purposes. Combined with their popular use in dermatology, their availability, and the development of antimicrobial resistance, commercial essential oils are often an option for therapy. At least 90 essential oils can be identified as being recommended for dermatological use, with at least 1500 combinations. This review explores the fundamental knowledge available on the antimicrobial properties against pathogens responsible for dermatological infections and compares the scientific evidence to what is recommended for use in common layman's literature. Also included is a review of combinations with other essential oils and antimicrobials. The minimum inhibitory concentration dilution method is the preferred means of determining antimicrobial activity. While dermatological skin pathogens such as Staphylococcus aureus have been well studied, other pathogens such as Streptococcus pyogenes, Propionibacterium acnes, Haemophilus influenzae, and Brevibacterium species have been sorely neglected. Combination studies incorporating oil blends, as well as interactions with conventional antimicrobials, have shown that mostly synergy is reported. Very few viral studies of relevance to the skin have been made. Encouragement is made for further research into essential oil combinations with other essential oils, antimicrobials, and carrier oils. PMID:28546822

  19. Linear sweep voltammetric studies on the supramolecular complex of alizarin red S with lysozyme and determination of lysozyme

    Indian Academy of Sciences (India)

    Wei Sun; Na Zhao; Xueliang Niu; Yan Wang; Kui Jiao

    2009-03-01

    An electrochemical method for the determination of lysozyme (LYS) based on its interaction with alizarin red S (ARS) was established by linear sweep voltammetry in this paper. The electrochemical behaviour of ARS with LYS was investigated on a dropping mercury working electrode in 0.2 mol/L pH 4.8 Britton-Robinson (B-R) buffer solution. ARS showed a sensitive second order derivative linear sweep voltammetric reductive peak at -0.42 V (vs SCE). After the addition of LYS, the reductive peak current of ARS decreased without the shift of the reductive peak potential and no new waves appeared, which was due to the formation of a supramolecular complex of ARS with LYS in the solution. The stoichiometry of the ARS-LYS complex was further calculated by the electrochemical data with the results of the binding ratio as 3 : 1 and the binding constant as 2.82 × 1014. Under the selected conditions, the decrease of the second order derivative linear sweep voltammetric reductive peak current of ARS was in proportion to the LYS concentration in the range from 0.8 to 35.0 mg/L and the detection limit of LYS was calculated as 0.52 mg/L (3). Different kinds of LYS samples were detected satisfactorily with this method.

  20. Tear Lipids Interfacial Rheology: Effect of Lysozyme and Lens Care Solutions

    Science.gov (United States)

    Svitova, Tatyana F.; Lin, Meng C.

    2014-01-01

    Purpose To evaluate the interfacial properties of ex vivo tear lipid multilayers with controlled and varying thickness. The influence of lysozyme and surfactant-containing multi-purpose lens care solutions (MPS) on interfacial rheology of lipids and mixed lipid-protein films were studied. Methods Lipids were extracted from lotrafilcon A lenses worn continuously for 1 month. Interfacial properties of the lipids without and with lysozyme in the aqueous phase were examined using tensiometry and step-strain relaxation. Lipid-lysozyme multilayers were exposed to either diluted Optifree Express (OFX) or Optifree Replenish (OFR) for 30 min, and then MPS was displaced from the bulk phase. Surface tension and rheological parameters before and after MPS exposure were measured and compared. Results Thick lipid films exerted high surface pressure at the air-aqueous interface, 50 ± 2 mN/m, with little inter- and intra-subject variability. The rheological storage modulus (E∞; 25.3 ± 2 mN/m) and relaxation time (τ; 87 ± 25 s) were similar among subjects. Neither lysozyme nor MPS changed the surface tension of the lipid multilayers. Lysozyme adsorbed irreversibly onto multilayers without changing E∞, but increased τ 2.5 times. Exposure of mixed multilayers to OFX reduced E∞ to less than a half of its original value (13 ± 4.5 mN/m; p rheology of the ex vivo lipids. OFX and OFR changed rheological properties of the mixed films to different extents. PMID:19901859

  1. A comparison of the physical properties of ultrasonically synthesized lysozyme- and BSA-shelled microbubbles.

    Science.gov (United States)

    Vong, Fiona; Son, Younggyu; Bhuiyan, Sadia; Zhou, Meifang; Cavalieri, Francesca; Ashokkumar, Muthupandian

    2014-01-01

    Ultrasonic technique has been used for synthesising protein microspheres possessing specific physical and functional properties. Various proteins have been used as shell materials under different experimental conditions. In previous studies, thermal or chemical denaturation of the proteins was used to obtain stable bovine-serum albumin (BSA) and lysozyme microbubbles (MBs), respectively. It is ideal to establish a generic procedure to synthesise microspheres irrespective of the nature of the protein. In order to see if a generic procedure can be established, ultrasonic synthesis of lysozyme and BSA MBs was carried out under similar experimental conditions and their properties were evaluated. The size, size distribution and the stability of the MBs were significantly different for the lysozyme and BSA MBs. The size and size distribution of the lysozyme coated MBs were larger than BSA bubbles. The mechanical strength of MBs against the shear forces, generated when irradiated by high frequency ultrasound, was studied using pulsed-sonoluminescence (SL). This study indicated that lysozyme MBs were significantly more stable than BSA MBs. An increase in mechanical strength of the MBs may lead to an increase in their storage lifetime and stability against gas diffusion. Possible reasons for such observations have been discussed.

  2. Characterizing protein activities on the lysozyme and nanodiamond complex prepared for bio applications.

    Science.gov (United States)

    Perevedentseva, E; Cai, P-J; Chiu, Y-C; Cheng, C-L

    2011-02-01

    Recently, nanodiamond particles have attracted increasing attention as a promising nanomaterial for its biocompatibility, easy functionalization and conjugation with biomolecules, and its superb physical/chemical properties. Nanodiamonds are mainly used as markers for cell imaging, using its fluorescence or Raman signals for detection, and as carriers for drug delivery. For the success of these applications, the biomolecule associated with the nanodiamond has to retain its functionality. In this work, the protein activities of egg white lysozyme adsorbed on nanodiamond particles of different sizes is investigated. The lysozyme nanodiamond complex is used here as a protein model for analyzing its structural conformation changes and, correspondingly, its enzymatic activity after the adsorption. Fourier-transform infrared spectroscopy (FTIR) is used for the analysis of the sensitive protein secondary structure. To access the activities of the adsorbed lysozyme, a fluorescence-based assay is used. The process of adsorption is also analyzed using UV-visible spectroscopic measurements in combination with analysis of nanodiamond properties with FTIR, Raman spectroscopy, and ζ-potential measurements. It is found that the activity of lysozyme upon adsorption depends on the nanodiamond's size and surface properties, and that the nanodiamond particles can be selected and treated, which do not alter the lysozyme functional properties. Such nanodiamonds can be considered convenient nanoparticles for various bioapplications.

  3. Interaction of fullerenol with lysozyme investigated by experimental and computational approaches

    Energy Technology Data Exchange (ETDEWEB)

    Yang Shengtao; Wang Haifang; Guo Lin; Gao Yang; Liu Yuanfang [Beijing National Laboratory for Molecular Sciences, Department of Chemical Biology, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871 (China); Cao Aoneng [Institute of Nanochemistry and Nanobiology, Shanghai University, Shanghai 200444 (China)], E-mail: haifangw@pku.edu.cn, E-mail: ancao@shu.edu.cn

    2008-10-01

    The potential biomedical applications of fullerenol C{sub 60}(OH){sub x} (x{approx}24) have been extensively studied. However, the structural information of the interaction of fullerenol with the bio-system at the molecular level, which is essential for understanding its bioactivity and toxicity, is still missing. In this study, lysozyme was selected as a model protein to investigate the interaction between fullerenol and biomolecules. A strong induced circular dichroism (CD) signal of achiral fullerenol was observed after binding with lysozyme. Activity assay shows that lysozyme activity is inhibited significantly by fullerenol. No heat capacity difference between the folded and unfolded states of lysozyme was measured by differential scanning calorimetry (DSC) in the presence of fullerenol, indicating that fullerenol prefers to bind with the hydrophobic residues. Both experimental and Autodock computational results suggest that the binding site on lysozyme for fullerenol is close to Trp 62, and a {pi}-{pi} stacking interaction might play an important role in binding.

  4. Binding and Inhibitory Effect of the Dyes Amaranth and Tartrazine on Amyloid Fibrillation in Lysozyme.

    Science.gov (United States)

    Basu, Anirban; Suresh Kumar, Gopinatha

    2017-02-16

    Interaction of two food colorant dyes, amaranth and tartrazine, with lysozyme was studied employing multiple biophysical techniques. The dyes exhibited hypochromic changes in the presence of lysozyme. The intrinsic fluorescence of lysozyme was quenched by both dyes; amaranth was a more efficient quencher than tartrazine. The equilibrium constant of amaranth was higher than that of tartarzine. From FRET analysis, the binding distances for amaranth and tartrazine were calculated to be 4.51 and 3.93 nm, respectively. The binding was found to be dominated by non-polyelectrolytic forces. Both dyes induced alterations in the microenvironment surrounding the tryptophan and tyrosine residues of the protein, with the alterations being comparatively higher for the tryptophans than the tyrosines. The interaction caused significant loss in the helicity of lysozyme, the change being higher with amaranth. The binding of both dyes was exothermic. The binding of amaranth was enthalpy driven, while that of tartrazine was predominantly entropy driven. Amaranth delayed lysozyme fibrillation at 25 μM, while tartrazine had no effect even at 100 μM. Nevertheless, both dyes had a significant inhibitory effect on fibrillogenesis. The present study explores the potential antiamyloidogenic property of these azo dyes used as food colorants.

  5. Impact of a Reducing Agent on the Dynamic Surface Properties of Lysozyme Solutions.

    Science.gov (United States)

    Tihonov, Michael M; Kim, Viktoria V; Noskov, Boris A

    2016-05-01

    Disulfide bond shuffling in the presence of the reducing agents dithiothreitol (DTT) or β-mercaptoethanol (BME) strongly affects the surface properties of lysozyme solutions. The addition of 0.32 mM DTT substantially alters the kinetic dependencies of the dynamic surface elasticity and surface tension relative to those of pure protein solutions. The significant increase in the dynamic surface elasticity likely relates to the cross-linking between lysozyme molecules and the formation of a dense layer of protein globules stabilized by intermolecular disulfide bonds at the liquid/gas interface. This effect differs from the previously described influence of chaotropic denaturants, such as guanidine hydrochloride (GuHCl) and urea, on the surface properties of lysozyme solutions. If both chaotropic and reducing agents are added to protein solutions simultaneously, their effects become superimposed. In the case of mixed lysozyme/GuHCl/DTT solutions, the dynamic surface elasticity near equilibrium decreases as the GuHCl concentration increases because of the gradual loosening of the cross-linked layer of protein globules but remains much higher than that of lysozyme/GuHCl solutions.

  6. Fast Screening of Chicken Egg Lysozyme in White Wine Products by Extractive Electrospray Ionization Mass Spectrometry

    Institute of Scientific and Technical Information of China (English)

    ZHOU Zhi-quan; JIANG Jie; LI Ming; ZHAO Zhan-feng; FU Jun

    2012-01-01

    Fast detection of trace lysozyme,one of the most important food allergens in white wine samples,was achieved by extractive electrospray ionization mass spectrometry without sample pretreatment in this study.The multiply-charged ions of m/z 1587 were chosen for the quantitative detection of lysozyme in white wine,showing linear dynamic signal responses in a range of 5-75 μg/mL with a linearity coefficient of 0.999 and an acceptable relative standard deviation(RSD)of 8.0%-15.0% for directly measuring lysozyme in the complex food samples.The limit of detection for lysozyme in white wine sample was calculated to be 5 μg/mL,which was lower than the amounts that can provoke allergic reactions(oral test with 3 mg or labial test with 1 mg/mL).A single sample analysis was completed within 1 min.The data demonstrate that extractive electrospray ionization mass spectrometry is a useful tool for fast screening lysozyme in the complex matrix,showing promising application in the rapid detection of food allergen.

  7. A zinc complex of heparan sulfate destabilises lysozyme and alters its conformation

    Energy Technology Data Exchange (ETDEWEB)

    Hughes, Ashley J. [Institute of Integrative Biology, University of Liverpool, Liverpool L69 7ZB (United Kingdom); Diamond Light Source Ltd., Diamond House, Didcot, Oxfordshire OX11 0DE (United Kingdom); Hussain, Rohanah [Diamond Light Source Ltd., Diamond House, Didcot, Oxfordshire OX11 0DE (United Kingdom); Cosentino, Cesare; Guerrini, Marco [Istituto di Chimica e Biochimica ' G. Ronzoni' , Via G. Colombo 81, Milano 20133 (Italy); Siligardi, Giuliano [Diamond Light Source Ltd., Diamond House, Didcot, Oxfordshire OX11 0DE (United Kingdom); Yates, Edwin A., E-mail: eayates@liv.ac.uk [Institute of Integrative Biology, University of Liverpool, Liverpool L69 7ZB (United Kingdom); Rudd, Timothy R., E-mail: trudd@liv.ac.uk [Institute of Integrative Biology, University of Liverpool, Liverpool L69 7ZB (United Kingdom); Istituto di Chimica e Biochimica ' G. Ronzoni' , Via G. Colombo 81, Milano 20133 (Italy)

    2012-09-07

    Highlights: Black-Right-Pointing-Pointer Zinc-heparan sulfate complex destabilises lysozyme, a model amyloid protein. Black-Right-Pointing-Pointer Addition of zinc, without heparan sulfate, stabilises lysozyme. Black-Right-Pointing-Pointer Heparan sulfate cation complexes provide alternative protein folding routes. -- Abstract: The naturally occurring anionic cell surface polysaccharide heparan sulfate is involved in key biological activities and is implicated in amyloid formation. Following addition of Zn-heparan sulfate, hen lysozyme, a model amyloid forming protein, resembled {beta}-rich amyloid by far UV circular dichroism (increased {beta}-sheet: +25%), with a significantly reduced melting temperature (from 68 to 58 Degree-Sign C) by fluorescence shift assay. Secondary structure stability of the Zn-heparan sulfate complex with lysozyme was also distinct from that with heparan sulfate, under stronger denaturation conditions using synchrotron radiation circular dichroism. Changing the cation associated with heparan sulfate is sufficient to alter the conformation and stability of complexes formed between heparan sulfate and lysozyme, substantially reducing the stability of the protein. Complexes of heparan sulfate and cations, such as Zn, which are abundant in the brain, may provide alternative folding routes for proteins.

  8. Synthesis of Ag{sub 2}S nanorods by biomimetic method in the lysozyme matrix

    Energy Technology Data Exchange (ETDEWEB)

    Qin, Dezhi, E-mail: dezhiqin@163.com; Zhang, Li; He, Guoxu; Zhang, Qiuxia

    2013-09-01

    Graphical abstract: - Highlights: • Firstly, Ag{sub 2}S nanorods were synthesized by biomimetic method in the lysozyme solutions. • The study of the interaction between Ag{sup +} and the lysozyme. • Discussion of possible formation mechanism of Ag{sub 2}S nanorods. • The synthesis process of lyso-conjugated Ag{sub 2}S nanocrystals is facile, effective and environment friendly. - Abstract: Ag{sub 2}S nanorods were successfully synthesized by biomimetic route in the lysozyme solution at physiological temperature and atmospheric pressure. The transmission electron microscopy (TEM) images revealed that the prepared nanorods are uniform and monodisperse with homogeneous size about 50 nm in diameter and 150 nm in length. The optical property of Ag{sub 2}S nanocrystals was studied by the ultraviolet–visible (UV–vis) and photoluminescence (PL) spectroscopy, the results show that the products exhibit well-defined emission at 471 nm and 496 nm excited by 292 nm. The interaction of Ag{sup +}/Ag{sub 2}S with the lysozyme was investigated through Fourier transform infrared (FT-IR) spectroscopy, which shows that the cooperation effect of the lysozyme and Ag{sup +} could be responsible for the formation of as obtained Ag{sub 2}S nanorods.

  9. Single-molecule dynamics of lysozyme processing distinguishes linear and cross-linked peptidoglycan substrates.

    Science.gov (United States)

    Choi, Yongki; Moody, Issa S; Sims, Patrick C; Hunt, Steven R; Corso, Brad L; Seitz, David E; Blaszczak, Larry C; Blaszcazk, Larry C; Collins, Philip G; Weiss, Gregory A

    2012-02-01

    The dynamic processivity of individual T4 lysozyme molecules was monitored in the presence of either linear or cross-linked peptidoglycan substrates. Single-molecule monitoring was accomplished using a novel electronic technique in which lysozyme molecules were tethered to single-walled carbon nanotube field-effect transistors through pyrene linker molecules. The substrate-driven hinge-bending motions of lysozyme induced dynamic electronic signals in the underlying transistor, allowing long-term monitoring of the same molecule without the limitations of optical quenching or bleaching. For both substrates, lysozyme exhibited processive low turnover rates of 20-50 s(-1) and rapid (200-400 s(-1)) nonproductive motions. The latter nonproductive binding events occupied 43% of the enzyme's time in the presence of the cross-linked peptidoglycan but only 7% with the linear substrate. Furthermore, lysozyme catalyzed the hydrolysis of glycosidic bonds to the end of the linear substrate but appeared to sidestep the peptide cross-links to zigzag through the wild-type substrate.

  10. Antimicrobials in beekeeping.

    Science.gov (United States)

    Reybroeck, Wim; Daeseleire, Els; De Brabander, Hubert F; Herman, Lieve

    2012-07-06

    The bee diseases American and European foulbrood and nosemosis can be treated with anti-infectious agents. However, in the EU and the USA the use of these agents in beekeeping is strictly regulated due to the lack of tolerance (e.g. Maximum Residue Limit) for residues of antibiotics and chemotherapeutics in honey. This article reviews the literature dealing with antimicrobials of interest in apiculture, stability of these antimicrobials in honey, and disposition of the antimicrobials in honeybee hives.

  11. Molecular dynamics simulation of triclinic lysozyme in a crystal lattice.

    Science.gov (United States)

    Janowski, Pawel A; Liu, Chunmei; Deckman, Jason; Case, David A

    2016-01-01

    Molecular dynamics simulations of crystals can enlighten interpretation of experimental X-ray crystallography data and elucidate structural dynamics and heterogeneity in biomolecular crystals. Furthermore, because of the direct comparison against experimental data, they can inform assessment of molecular dynamics methods and force fields. We present microsecond scale results for triclinic hen egg-white lysozyme in a supercell consisting of 12 independent unit cells using four contemporary force fields (Amber ff99SB, ff14ipq, ff14SB, and CHARMM 36) in crystalline and solvated states (for ff14SB only). We find the crystal simulations consistent across multiple runs of the same force field and robust to various solvent equilibration schemes. However, convergence is slow compared with solvent simulations. All the tested force fields reproduce experimental structural and dynamic properties well, but Amber ff14SB maintains structure and reproduces fluctuations closest to the experimental model: its average backbone structure differs from the deposited structure by 0.37Å; by contrast, the average backbone structure in solution differs from the deposited by 0.65Å. All the simulations are affected by a small progressive deterioration of the crystal lattice, presumably due to imperfect modeling of hydrogen bonding and other crystal contact interactions; this artifact is smallest in ff14SB, with average lattice positions deviating by 0.20Å from ideal. Side-chain disorder is surprisingly low with fewer than 30% of the nonglycine or alanine residues exhibiting significantly populated alternate rotamers. Our results provide helpful insight into the methodology of biomolecular crystal simulations and indicate directions for future work to obtain more accurate energy models for molecular dynamics.

  12. Animation of Antimicrobial Resistance

    Medline Plus

    Full Text Available ... more understandable to non-scientists by showing how bacterial antimicrobial resistance can develop and spread. All FDA CVM ... Education Inspections & Compliance Federal, State & Local ...

  13. Animation of Antimicrobial Resistance

    Medline Plus

    Full Text Available ... Resistance National Antimicrobial Resistance Monitoring System 2014 NARMS ... Note: If you need help accessing information in different file formats, see Instructions for Downloading ...

  14. NURBS curve blending using extension

    Institute of Scientific and Technical Information of China (English)

    Yong-jin LIU; Rong-qi QIU; Xiao-hui LIANG

    2009-01-01

    Curve and surface blending is an important operation in CAD systems, in which a non-uniform rational B-spline (NURBS) has been used as the de facto standard. In local comer blending, two curves intersecting at that comer are first made disjoint, and then the third blending curve is added-in to smoothly join the two curves with G1-or G2-continuity. In this paper we present a study to solve the joint problem based on curve extension. The following nice properties of this extension algorithm are exploited in depth: (1) The parameterization of the original shapes does not change; (2) No additional fragments are created.Various examples are presented to demonstrate that our solution is simple and efficient.

  15. Blended Learning as Transformational Institutional Learning

    Science.gov (United States)

    VanDerLinden, Kim

    2014-01-01

    This chapter reviews institutional approaches to blended learning and the ways in which institutions support faculty in the intentional redesign of courses to produce optimal learning. The chapter positions blended learning as a strategic opportunity to engage in organizational learning.

  16. NESDIS Blended Rain Rate (RR) Products

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The blended Rain Rate (RR) product is derived from multiple sensors/satellites. The blended products were merged from polar-orbiting and geostationary satellite...

  17. Production of Silk & Wool Blended Worsted Cloth

    Institute of Scientific and Technical Information of China (English)

    段亚峰; 许琳

    2004-01-01

    Wool & silk blended fancy suiting is desinged. Through trial-production with silk sliver and Australian wool top, the spinning technology is investigated, and the relationship of spinning technology, blending ratio and yam construction is discussed.

  18. Blended Learning as Transformational Institutional Learning

    Science.gov (United States)

    VanDerLinden, Kim

    2014-01-01

    This chapter reviews institutional approaches to blended learning and the ways in which institutions support faculty in the intentional redesign of courses to produce optimal learning. The chapter positions blended learning as a strategic opportunity to engage in organizational learning.

  19. Statistical methods for assessment of blend homogeneity

    DEFF Research Database (Denmark)

    Madsen, Camilla

    2002-01-01

    as powder blends there is no natural unit or amount to define a sample from the blend, and partly that current technology does not provide a method of universally collecting small representative samples from large static powder beds. In the thesis a number of methods to assess (in)homogeneity are presented...... of internal factors to the blend e.g. the particle size distribution. The relation between particle size distribution and the variation in drug content in blend and tablet samples is discussed. A central problem is to develop acceptance criteria for blends and tablet batches to decide whether the blend...... blend or batch. In the thesis it is shown how to link sampling result and acceptance criteria to the actual quality (homogeneity) of the blend or tablet batch. Also it is discussed how the assurance related to a specific acceptance criteria can be obtained from the corresponding OC-curve. Further...

  20. SALIVARY ANTIMICROBIAL PROTEIN RESPONSE TO PROLONGED RUNNING

    Directory of Open Access Journals (Sweden)

    Suzanne Schneider

    2013-01-01

    Full Text Available Prolonged exercise may compromise immunity through a reduction of salivary antimicrobial proteins (AMPs. Salivary IgA (IgA has been extensively studied, but little is known about the effect of acute, prolonged exercise on AMPs including lysozyme (Lys and lactoferrin (Lac. Objective: To determine the effect of a 50-km trail race on salivary cortisol (Cort, IgA, Lys, and Lac. Methods: 14 subjects: (6 females, 8 males completed a 50km ultramarathon. Saliva was collected pre, immediately after (post and 1.5 hrs post race ( 1.5. Results: Lac concentration was higher at 1.5 hrs post race compared to post exercise (p0.05. IgA concentration, secretion rate, and IgA/Osm were lower 1.5 hrs post compared to pre race (p<0.05. Cort concentration was higher at post compared to 1.5 (p<0.05, but was unaltered from pre race levels. Subjects finished in 7.81 ± 1.2 hrs. Saliva flow rate did not differ between time points. Saliva Osm increased at post (p<0.05 compared to pre race. Conclusions: The intensity could have been too low to alter Lys and Lac secretion rates and thus, may not be as sensitive as IgA to changes in response to prolonged running. Results expand our understanding of the mucosal immune system and may have implications for predicting illness after prolonged running.

  1. The role of antimicrobial peptides in animal defenses

    Science.gov (United States)

    Hancock, Robert E. W.; Scott, Monisha G.

    2000-08-01

    It is becoming clear that the cationic antimicrobial peptides are an important component of the innate defenses of all species of life. Such peptides can be constitutively expressed or induced by bacteria or their products. The best peptides have good activities vs. a broad range of bacterial strains, including antibiotic-resistant isolates. They kill very rapidly, do not easily select resistant mutants, are synergistic with conventional antibiotics, other peptides, and lysozyme, and are able to kill bacteria in animal models. It is known that bacterial infections, especially when treated with antibiotics, can lead to the release of bacterial products such as lipopolysaccharide (LPS) and lipoteichoic acid, resulting in potentially lethal sepsis. In contrast to antibiotics, the peptides actually prevent cytokine induction by bacterial products in tissue culture and human blood, and they block the onset of sepsis in mouse models of endotoxemia. Consistent with this, transcriptional gene array experiments using a macrophage cell line demonstrated that a model peptide, CEMA, blocks the expression of many genes whose transcription was induced by LPS. The peptides do this in part by blocking LPS interaction with the serum protein LBP. In addition, CEMA itself has a direct effect on macrophage gene expression. Because cationic antimicrobial peptides are induced by LPS and are able to dampen the septic response of animal cells to LPS, we propose that, in addition to their role in direct and lysozyme-assisted killing of microbes, they have a role in feedback regulation of cytokine responses. We are currently developing variant peptides as therapeutics against antibiotic-resistant infections.

  2. High-level recombinant human lysozyme expressed in milk of transgenic pigs can inhibit the growth of Escherichia coli in the duodenum and influence intestinal morphology of sucking pigs.

    Directory of Open Access Journals (Sweden)

    Dan Lu

    Full Text Available Lysozyme is often used as a feed additive and acts as an antimicrobial protein that enhances immune function and defends against pathogenic bacteria in pigs. In this study, we genetically added recombinant human lysozyme (rhLZ to sow milk by somatic cell nuclear transfer and investigated whether the presence of recombinant human lysozyme can influence intestinal microbiota and morphology in sucking pigs. We generated transgenic cloned pigs and the first-generation hybrids (F1 produced high levels of rhLZ in milk. The average concentration of rhLZ was 116.34 ± 24.46 mg/L in the milk of F1 sows, which was 1500-fold higher than that of the native pig lysozyme. In vitro, it was demonstrated that rhLZ in milk of transgenic pigs had enzyme levels at 92,272 ± 26,413 U/mL. In a feeding experiment, a total of 40 newborn piglets were nursed by four transgenic sows and four sibling non-transgenic sows (F1, with five piglets per gilt. The piglets were allowed to nurse for 21 days and the sow milk was the only source of nutrition for the piglets. All piglets were slaughtered on postnatal day 22. Six types of bacteria were cultured and analyzed to detect the impact of rhLZ on gut microbiota. The number of Escherichia coli in the duodenum of piglets reared by transgenic sows was significantly decreased (p<0.001 and their villus height to crypt depth ratio in the intestine were increased due to the significant decrease of crypt depth in the duodenum, jejunum, and ileum (p<0.001. Together, we successfully generated rhLZ transgenic cloned pigs and elevated lysozyme level in nuring piglets. The results of the feeding experiments demonstrated that rhLZ-enhanced milk can inhibit the growth of E. coli in the duodenum and positively influence intestinal morphology without adversely affecting weight gain or piglet growth.

  3. C-terminus of TRAP in Staphylococcus can enhance the activity of lysozyme and lysostaphin

    Institute of Scientific and Technical Information of China (English)

    Guang Yang; Ningsheng Shao; Yaping Gao; Jiannan Feng; Yong Huang; Shaohua Li; Yu Liu; Chuan Liu; Ming Fan; Beifen Shen

    2008-01-01

    In Staphylococcus aureus, the target of RNAⅢ activating protein (TRAP) is a membrane-associated protein whose Cterminus can be used as a vaccine to provide protection against staphylococcal infection. Here, we show for the first time by surface plasmon resonance and enzyme-linked immunosorbent assay that TRAP can specifically bind lysozyme and iysostaphin through its C-terminus (amino acids 155-167) and enhance lysozomal activities in vitro. It was also found that the traP mutant strain is more resistant to iysostaphin than wild-type. Our previous data showed that the C-terminus of TRAP might be extracellular. So our results suggested that the C-terminus of TRAP could act as the specific targeting protein of the lysozyme/lysostaphin on the S. aureus cell wall and the biological significance of the interaction might be to facilitate lysozyme/lysostaphin-mediated cell iysis.

  4. Refolding of detergent-denatured lysozyme using β-cyclodextrin-assisted ion exchange chromatography.

    Science.gov (United States)

    Zhang, Li; Zhang, Qinming; Wang, Chaozhan

    2013-03-01

    Chromatography-based protein refolding is widely used. Detergent is increasingly used for protein solubilization from inclusion bodies. Therefore, it is necessary to develop a refolding method for detergent-denatured/solubilized proteins based on liquid chromatography. In the present work, sarkosyl-denatured/dithiothreitol-reduced lysozyme was used as a model, and a refolding method based on ion exchange chromatography, assisted by β-cyclodextrin, was developed for refolding detergent-denatured proteins. Many factors affecting the refolding, such as concentration of urea, concentration of β-cyclodextrin, pH and flow rate of mobile phases, were investigated to optimize the refolding conditions for sarkosyl-denatured lysozymes. The results showed that the sarkosyl-denatured lysozyme could be successfully refolded using β-cyclodextrin-assisted ion exchange chromatography.

  5. Viscometric study of lysozyme solution with sugar and urea at various temperatures

    Directory of Open Access Journals (Sweden)

    Jamal Akhter Siddique

    2016-11-01

    at temperatures (293.15, 303.15, 313.13 and 323.15 K at various concentrations of glucose, maltose and urea. Change in entropy (ΔH, enthalpy (ΔS and free energy of activation (ΔG have also been evaluated for these systems. Value of B-coefficient of d (− glucose, maltose and urea has also been calculated from viscosity data in aqueous lysozyme solution. Viscosity B-coefficients of glucose and maltose in aqueous lysozyme solution are positive while that of the urea–lysozyme water system it is negative due to the structure breaking effect of urea. The values of entropy of activation are negative due to attainment of transition state for viscous flow, which is accompanied by bond formation and increase in order.

  6. Blended Identities: Identity Work, Equity and Marginalization in Blended Learning

    Science.gov (United States)

    Heikoop, Will

    2013-01-01

    This article is a theoretical study of the self-presentation strategies employed by higher education students online; it examines student identity work via profile information and avatars in a blended learning environment delivered through social networking sites and virtual worlds. It argues that students are faced with difficult choices when…

  7. Effects of modified {beta}-cyclodextrin on thermal stability and conformation of lysozyme

    Energy Technology Data Exchange (ETDEWEB)

    Kamiyama, Tadashi, E-mail: kamiyama@chem.kindai.ac.jp [Department of Chemistry, School of Science and Engineering, Kinki University, Kowakae 3-4-1, Higashi-Osaka, Osaka 577-8502 (Japan); Satoh, Megumi; Tateishi, Takahiro; Nojiri, Tomoaki; Takeuchi, Daisuke; Kimura, Takayoshi [Department of Chemistry, School of Science and Engineering, Kinki University, Kowakae 3-4-1, Higashi-Osaka, Osaka 577-8502 (Japan)

    2012-03-20

    Highlights: Black-Right-Pointing-Pointer Effects of cyclodextrin on stability and conformation of lysozyme were clarified. Black-Right-Pointing-Pointer The CD influences the hydrophobic interaction of lysozyme by the inclusion. Black-Right-Pointing-Pointer The CD relatively destabilized the folded state by stabilizing the unfolded state. Black-Right-Pointing-Pointer The destabilization depends on the concentration and the substituent of CD. Black-Right-Pointing-Pointer The conformation of lysozyme was more spread at unfolded state by inclusion of CD. - Abstract: Effects of cyclic oligosaccharide cyclodextrin (CD) on stability and conformation of lysozyme were clarified thermodynamically and rheologically by DSC, viscosity, and circular dichroism measurements. The modified {beta}-CD relatively destabilized the folded state of lysozyme by stabilizing the unfolded state due to inclusion of hydrophobic part into the hydrophobic interior of CD. The order of higher destabilization effect was acetyl-{beta}-CD > methyl-{beta}-CD > hydroxypropyl-{beta}-CD. Apparent number of bound CD to unfolded state for methyl-, hydroxypropyl-, and acetyl-{beta}-CD is 6.7 {+-} 0.7, 4.2 {+-} 1.1, and 18.6 {+-} 4.3 and the binding constant is 5.5 {+-} 0.8, 6.7 {+-} 2.4, and 4.4 {+-} 1.2 L mol{sup -1}, respectively. The viscosity for unfolded state was increased with an increase in the each modified {beta}-CD concentration, suggesting that the inclusion of CD on a part of hydrophobic core at unfolded state leads to break the hydrophobic core, then lysozyme would be more spread structure. The substituent of CD can accelerate instability by directly breaking hydrogen bond and/or can restrain instability by increase in hydrophobic interaction. The fact that the each modified CDs has different destabilization effect shows a possibility to control the stability of protein by the substitution of CD.

  8. 7 CFR 989.16 - Blend.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 8 2010-01-01 2010-01-01 false Blend. 989.16 Section 989.16 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Marketing Agreements and... CALIFORNIA Order Regulating Handling Definitions § 989.16 Blend. Blend means to mix or commingle raisins. ...

  9. Radiation effects on LDPE/EVA blends

    Energy Technology Data Exchange (ETDEWEB)

    Sharif, Jamaliah; Aziz, S.H.S.A.Sharifah Hanisah Syed Abdul; Hashim, Kamaruddin

    2000-04-01

    The effect of radiation on the properties of low density polyethylene (LDPE) and ethylene vinyl acetate (EVA) blends were investigated. The improvement of the measured gel content, thermal elongation, tensile strength, elongation at break and heat deformation of the blends have confirmed the positive effect of electron beam irradiation on the blends.

  10. The Effect of pH Difference Between Two Phases on the Partition of Lysozyme in Aqueous Two-Phase System

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    In the investigation of effect of KSCN on the partitioning of lysozyme in PEG2000/ammonium sulfate aqueous two-phase system, it was found that the KSCN could alter the pH difference between the two phases, and thus affect the partition of lysozyme. The relationship between partition coefficients of lysozyme and pH differences between two phases was discussed.

  11. How do trehalose, maltose and sucrose influence some structural and dynamical properties of lysozyme ? An insight from Molecular Dynamics simulations

    CERN Document Server

    Lerbret, A; Affouard, F; Hedoux, A; Guinet, Y; Descamps, M

    2007-01-01

    The influence of three well-known disaccharides, namely trehalose, maltose and sucrose, on some structural and dynamical properties of lysozyme has been investigated by means of molecular dynamics computer simulations in the 37-60 wt % concentration range. The effects of sugars on the protein conformation are found relatively weak, in agreement with the preferential hydration of lysozyme. Conversely, sugars seem to increase significantly the relaxation times of the protein. These effects are shown to be correlated to the fractional solvent accessibilities of lysozyme residues and further support the slaving of protein dynamics. Moreover, a significant increase in the relaxation times of lysozyme, sugars and water molecules is observed within the studied concentration range and may result from the percolation of the hydrogen-bond network of sugar molecules. This percolation appears to be of primary importance to explain the influence of sugars on the dynamical properties of lysozyme and water.

  12. Evidence of Conformational Changes in Adsorbed Lysozyme Molecule on Silver Colloids

    CERN Document Server

    Chandra, Goutam; Dasgupta, Swagata; Roy, Anushree

    2010-01-01

    In this article, we discuss metal-protein interactions in the Ag-lysozyme complex by spectroscopic measurements. The analysis of the variation in relative intensities of SERS bands reveal the orientation and the change in conformation of the protein molecules on the Ag surface with time. The interaction kinetics of metal-protein complexes has been analyzed over a period of three hours via both Raman and absorption measurements. Our analysis indicates that the Ag nanoparticles most likely interact with Trp-123 which is in close proximity to Phe-34 of the lysozyme molecule.

  13. Quantifying Main Trends in Lysozyme Nucleation: The Effects of Precipitant Concentration, Supersaturation and Impurities

    Science.gov (United States)

    Burke, Michael W.; Leardi, Riccardo; Judge, Russell A.; Pusey, Marc L.; Whitaker, Ann F. (Technical Monitor)

    2001-01-01

    Full factorial experimental design incorporating multi-linear regression analysis of the experimental data allows quick identification of main trends and effects using a limited number of experiments. In this study these techniques were employed to identify the effect of precipitant concentration, supersaturation, and the presence of an impurity, the physiological lysozyme dimer, on the nucleation rate and crystal dimensions of the tetragonal forin of chicken egg white lysozyme. Decreasing precipitant concentration, increasing supers aturation, and increasing impurity, were found to increase crystal numbers. The crystal axial ratio decreased with increasing precipitant concentration, independent of impurity.

  14. Rapid separation of lysozyme from chicken egg white by reductants and thermal treatment.

    Science.gov (United States)

    Chang, H M; Yang, C C; Chang, Y C

    2000-02-01

    Reductants (0.1-2.0% ascorbic acid, cysteine, or cystine and 0.04-1. 0% beta-mercaptoethanol) were added to 5-fold diluted, salted duck egg whites (commercially and laboratory prepared) and fresh egg whites (chicken and duck), and subsequently the mixtures were heated at 70 degrees C for 1-10 min. The maximal recovery and purification fold of lysozyme obtained from fresh chicken egg whites added with 1. 0% ascorbic acid were 78% and 2.4, respectively. Storage tests showed that the obtained lyophilized lysozyme powder after dialysis was stable when refrigerated at 4 degrees C for 3 months.

  15. The protective effect of salicylic acid on lysozyme against riboflavin-mediated photooxidation

    Science.gov (United States)

    Li, Kun; Wang, Hongbao; Cheng, Lingli; Zhu, Hui; Wang, Mei; Wang, Shi-Long

    2011-06-01

    As a metabolite of aspirin in vivo, salicylic acid was proved to protect lysozyme from riboflavin-mediated photooxidation in this study. The antioxidative properties of salicylic acid were further studied by using time-resolved laser flash photolysis of 355 nm. It can quench the triplet state of riboflavin via electron transfer from salicylic acid to the triplet state of riboflavin with a reaction constant of 2.25 × 10 9 M -1 s -1. Mechanism of antioxidant activities of salicylic acid on lysozyme oxidation was discussed. Salicylic acid can serve as a potential antioxidant to quench the triplet state of riboflavin and reduce oxidative pressure.

  16. Animation of Antimicrobial Resistance

    Medline Plus

    Full Text Available ... use of antimicrobial drugs will result in the development of resistant strains of bacteria, complicating clinician's efforts to select the appropriate antimicrobial for treatment. Accordingly, efforts are underway in both veterinary and human medicine to preserve the effectiveness of these drugs. ...

  17. Animation of Antimicrobial Resistance

    Medline Plus

    Full Text Available ... Skip to common links HHS U.S. Department of Health and Human Services U.S. Food and Drug Administration ... Tobacco Products Animal & Veterinary Home Animal & Veterinary Safety & Health Antimicrobial Resistance Animation of Antimicrobial Resistance Share Tweet ...

  18. Animation of Antimicrobial Resistance

    Medline Plus

    Full Text Available ... CVM produced material may be copied, reproduced, and distributed as long as FDA's Center for Veterinary Medicine ... More in Antimicrobial Resistance National Antimicrobial Resistance Monitoring ... Note: If you need help accessing information in different file formats, see Instructions for Downloading ...

  19. Antimicrobial Peptides in 2014

    Directory of Open Access Journals (Sweden)

    Guangshun Wang

    2015-03-01

    Full Text Available This article highlights new members, novel mechanisms of action, new functions, and interesting applications of antimicrobial peptides reported in 2014. As of December 2014, over 100 new peptides were registered into the Antimicrobial Peptide Database, increasing the total number of entries to 2493. Unique antimicrobial peptides have been identified from marine bacteria, fungi, and plants. Environmental conditions clearly influence peptide activity or function. Human α-defensin HD-6 is only antimicrobial under reduced conditions. The pH-dependent oligomerization of human cathelicidin LL-37 is linked to double-stranded RNA delivery to endosomes, where the acidic pH triggers the dissociation of the peptide aggregate to release its cargo. Proline-rich peptides, previously known to bind to heat shock proteins, are shown to inhibit protein synthesis. A model antimicrobial peptide is demonstrated to have multiple hits on bacteria, including surface protein delocalization. While cell surface modification to decrease cationic peptide binding is a recognized resistance mechanism for pathogenic bacteria, it is also used as a survival strategy for commensal bacteria. The year 2014 also witnessed continued efforts in exploiting potential applications of antimicrobial peptides. We highlight 3D structure-based design of peptide antimicrobials and vaccines, surface coating, delivery systems, and microbial detection devices involving antimicrobial peptides. The 2014 results also support that combination therapy is preferred over monotherapy in treating biofilms.

  20. ANTIMICROBIAL HERBAL DRUGS

    Directory of Open Access Journals (Sweden)

    K. Nishteswar

    2011-12-01

    Full Text Available An anti-microbial is a substance that kills or inhibits the growth of microorganisms such as bacteria, fungi, or protozoans. Antimicrobial drugs either kill microbes (microbiocidal or prevent the growth of microbes (microbiostatic. Sulphonamide drugs were the first antimicrobial drugs, and paved the way for the antibiotic revolution in medicine. The first sulfonamide, trade named Prontosil, was actually a prodrug. However, with the development of antimicrobials, microorganisms have adapted and become resistant to previous antimicrobial agents. In view of certain side effects caused due to usage of modern antimicrobial drugs and antibiotics scientists have made some attempts to screen some of the Ayurvedic herbs, which possess broader spectrum of safety. Some selected herbs which are used by tribal and rural people for curing various infective diseases caused due to bacteria, virus and fungi have been reported to possess anti-microbial properties. In the present paper and attempt is made to review about the indigenous medicinal plant which exhibited antimicrobial properties.

  1. Dissimilar Regulation of Antimicrobial Proteins in the Midgut of Spodoptera exigua Larvae Challenged with Bacillus thuringiensis Toxins or Baculovirus.

    Directory of Open Access Journals (Sweden)

    Cristina M Crava

    Full Text Available Antimicrobial peptides (AMPs and lysozymes are the main effectors of the insect immune system, and they are involved in both local and systemic responses. Among local responses, midgut immune reaction plays an important role in fighting pathogens that reach the insect body through the oral route, as do many microorganisms used in pest control. Under this point of view, understanding how insects defend themselves locally during the first phases of infections caused by food-borne pathogens is important to further improve microbial control strategies. In the present study, we analyzed the transcriptional response of AMPs and lysozymes in the midgut of Spodoptera exigua (Lepidoptera: Noctuidae, a polyphagous pest that is commonly controlled by products based on Bacillus thuringiensis (Bt or baculovirus. First, we comprehensively characterized the transcripts encoding AMPs and lysozymes expressed in S. exigua larval midgut, identifying 35 transcripts that represent the S. exigua arsenal against microbial infection. Secondly, we analyzed their expression in the midgut after ingestion of sub-lethal doses of two different pore-forming B. thuringiensis toxins, Cry1Ca and Vip3Aa, and the S. exigua nucleopolyhedrovirus (SeMNPV. We observed that both Bt toxins triggered a similar, wide and in some cases high transcriptional activation of genes encoding AMPs and lysozymes, which was not reflected in the activation of the classical systemic immune-marker phenoloxidase in hemolymph. Baculovirus ingestion resulted in the opposed reaction: Almost all transcripts coding for AMPs and lysozymes were down-regulated or not induced 96 hours post infection. Our results shed light on midgut response to different virulence factors or pathogens used nowadays as microbial control agents and point out the importance of the midgut immune response contribution to the larval immunity.

  2. Dissimilar Regulation of Antimicrobial Proteins in the Midgut of Spodoptera exigua Larvae Challenged with Bacillus thuringiensis Toxins or Baculovirus

    Science.gov (United States)

    Crava, Cristina M.; Jakubowska, Agata K.; Escriche, Baltasar; Herrero, Salvador; Bel, Yolanda

    2015-01-01

    Antimicrobial peptides (AMPs) and lysozymes are the main effectors of the insect immune system, and they are involved in both local and systemic responses. Among local responses, midgut immune reaction plays an important role in fighting pathogens that reach the insect body through the oral route, as do many microorganisms used in pest control. Under this point of view, understanding how insects defend themselves locally during the first phases of infections caused by food-borne pathogens is important to further improve microbial control strategies. In the present study, we analyzed the transcriptional response of AMPs and lysozymes in the midgut of Spodoptera exigua (Lepidoptera: Noctuidae), a polyphagous pest that is commonly controlled by products based on Bacillus thuringiensis (Bt) or baculovirus. First, we comprehensively characterized the transcripts encoding AMPs and lysozymes expressed in S. exigua larval midgut, identifying 35 transcripts that represent the S. exigua arsenal against microbial infection. Secondly, we analyzed their expression in the midgut after ingestion of sub-lethal doses of two different pore-forming B. thuringiensis toxins, Cry1Ca and Vip3Aa, and the S. exigua nucleopolyhedrovirus (SeMNPV). We observed that both Bt toxins triggered a similar, wide and in some cases high transcriptional activation of genes encoding AMPs and lysozymes, which was not reflected in the activation of the classical systemic immune-marker phenoloxidase in hemolymph. Baculovirus ingestion resulted in the opposed reaction: Almost all transcripts coding for AMPs and lysozymes were down-regulated or not induced 96 hours post infection. Our results shed light on midgut response to different virulence factors or pathogens used nowadays as microbial control agents and point out the importance of the midgut immune response contribution to the larval immunity. PMID:25993013

  3. Dissimilar Regulation of Antimicrobial Proteins in the Midgut of Spodoptera exigua Larvae Challenged with Bacillus thuringiensis Toxins or Baculovirus.

    Science.gov (United States)

    Crava, Cristina M; Jakubowska, Agata K; Escriche, Baltasar; Herrero, Salvador; Bel, Yolanda

    2015-01-01

    Antimicrobial peptides (AMPs) and lysozymes are the main effectors of the insect immune system, and they are involved in both local and systemic responses. Among local responses, midgut immune reaction plays an important role in fighting pathogens that reach the insect body through the oral route, as do many microorganisms used in pest control. Under this point of view, understanding how insects defend themselves locally during the first phases of infections caused by food-borne pathogens is important to further improve microbial control strategies. In the present study, we analyzed the transcriptional response of AMPs and lysozymes in the midgut of Spodoptera exigua (Lepidoptera: Noctuidae), a polyphagous pest that is commonly controlled by products based on Bacillus thuringiensis (Bt) or baculovirus. First, we comprehensively characterized the transcripts encoding AMPs and lysozymes expressed in S. exigua larval midgut, identifying 35 transcripts that represent the S. exigua arsenal against microbial infection. Secondly, we analyzed their expression in the midgut after ingestion of sub-lethal doses of two different pore-forming B. thuringiensis toxins, Cry1Ca and Vip3Aa, and the S. exigua nucleopolyhedrovirus (SeMNPV). We observed that both Bt toxins triggered a similar, wide and in some cases high transcriptional activation of genes encoding AMPs and lysozymes, which was not reflected in the activation of the classical systemic immune-marker phenoloxidase in hemolymph. Baculovirus ingestion resulted in the opposed reaction: Almost all transcripts coding for AMPs and lysozymes were down-regulated or not induced 96 hours post infection. Our results shed light on midgut response to different virulence factors or pathogens used nowadays as microbial control agents and point out the importance of the midgut immune response contribution to the larval immunity.

  4. Alternative Antimicrobial Approach: Nano-Antimicrobial Materials

    Directory of Open Access Journals (Sweden)

    Nurit Beyth

    2015-01-01

    Full Text Available Despite numerous existing potent antibiotics and other antimicrobial means, bacterial infections are still a major cause of morbidity and mortality. Moreover, the need to develop additional bactericidal means has significantly increased due to the growing concern regarding multidrug-resistant bacterial strains and biofilm associated infections. Consequently, attention has been especially devoted to new and emerging nanoparticle-based materials in the field of antimicrobial chemotherapy. The present review discusses the activities of nanoparticles as an antimicrobial means, their mode of action, nanoparticle effect on drug-resistant bacteria, and the risks attendant on their use as antibacterial agents. Factors contributing to nanoparticle performance in the clinical setting, their unique properties, and mechanism of action as antibacterial agents are discussed in detail.

  5. Molecular Characterization of a Lysozyme Gene and Its Altered Expression Profile in Crowded Beet Webworm (Loxostege sticticalis)

    Science.gov (United States)

    Kong, Hailong; Lv, Min; Mao, Nian; Wang, Cheng; Cheng, Yunxia; Zhang, Lei; Jiang, Xingfu; Luo, Lizhi

    2016-01-01

    There is growing evidence that insects living in high-density populations exhibit an increase in immune function to counter a higher risk of disease. This phenomenon, known as density-dependent prophylaxis, has been experimentally tested in a number of insect species. Although density-dependent prophylaxis is especially prevalent in insects exhibiting density-dependent phase polyphenism, the molecular mechanism remains unclear. Our previous study demonstrated that the antibacterial activity of lysozyme is important for this process in the beet webworm Loxostege sticticalis. In this study, a lysozyme cDNA from L. sticticalis was cloned and characterized. The full-length cDNA is 1078 bp long and contains an open reading frame of 426 bp that encodes 142 amino acids. The deduced protein possesses structural characteristics of a typical c-type lysozyme and clusters with c-type lysozymes from other Lepidoptera. LsLysozyme was found to be expressed throughout all developmental stages, showing the highest level in pupae. LsLysozyme was also highly expressed in the midgut and fat body. Elevated LsLysozyme expression was observed in L. sticticalis larvae infected by Beauveria bassiana and in larvae reared under crowding conditions. In addition, the expression level of LsLysozyme in infected larvae reared at a density of 10 larvae per jar was significantly higher compared to those reared at a density of l or 30 larvae per jar. These results suggest that larval crowding affects the gene expression profile of this lysozyme. This study provides additional insight into the expression of an immune-associated lysozyme gene and helps us to better understand the immune response of L. sticticalis under crowding conditions. PMID:27575006

  6. Netbaserede uddannelser og blended learning

    DEFF Research Database (Denmark)

    Bertelsen, Jesper Vedel; Vognsgaard Hjernø, Henriette; Jensen, Michael Peter

    2016-01-01

    Denne håndbog er tænkt som inspiration til uddannelsesfaglige medarbejdere, som er eller skal i gang med at undervise på en netbaseret uddannelse i UCL. Håndbogen giver et teoretisk overblik i forhold til netbaserede uddannelser, online- og blended learning samt en indførsel i hvilke didaktiske...

  7. Improvement of biodiesel methanol blends

    Directory of Open Access Journals (Sweden)

    Y. Datta Bharadwaz

    2016-06-01

    Full Text Available The main objective of this work was to improve the performance of biodiesel–methanol blends in a VCR engine by using optimized engine parameters. For optimization of the engine, operational parameters such as compression ratio, fuel blend, and load are taken as factors, whereas performance parameters such as brake thermal efficiency (Bth and brake specific fuel consumption (Bsfc and emission parameters such as carbon monoxide (CO, unburnt hydrocarbons (HC, Nitric oxides (NOx and smoke are taken as responses. Experimentation is carried out as per the design of experiments of the response surface methodology. Optimization of engine operational parameters is carried out using Derringers Desirability approach. From the results obtained it is inferred that the VCR engine has maximum performance and minimum emissions at 18 compression ratio, 5% fuel blend and at 9.03 kg of load. At this optimized operating conditions of the engine the responses such as brake thermal efficiency, brake specific fuel consumption, carbon monoxide, unburnt hydrocarbons, nitric oxide, and smoke are found to be 31.95%, 0.37 kg/kW h, 0.036%, 5 ppm, 531.23 ppm and 15.35% respectively. It is finally observed from the mathematical models and experimental data that biodiesel methanol blends have maximum efficiency and minimum emissions at optimized engine parameters.

  8. New Faces of Blended Learning

    Science.gov (United States)

    Horn, Michael B.; Fisher, Julia Freeland

    2017-01-01

    The Clayton Christiansen Institute maintains a database of more than 400 schools across the United States that have implemented some form of blended learning, which combines online learning with brick-and-mortar classrooms. Data the Institute has collected over the past six months suggests three trends as this model continues to evolve and mature.…

  9. Antimicrobial prophylaxis in adults.

    Science.gov (United States)

    Enzler, Mark J; Berbari, Elie; Osmon, Douglas R

    2011-07-01

    Antimicrobial prophylaxis is commonly used by clinicians for the prevention of numerous infectious diseases, including herpes simplex infection, rheumatic fever, recurrent cellulitis, meningococcal disease, recurrent uncomplicated urinary tract infections in women, spontaneous bacterial peritonitis in patients with cirrhosis, influenza, infective endocarditis, pertussis, and acute necrotizing pancreatitis, as well as infections associated with open fractures, recent prosthetic joint placement, and bite wounds. Perioperative antimicrobial prophylaxis is recommended for various surgical procedures to prevent surgical site infections. Optimal antimicrobial agents for prophylaxis should be bactericidal, nontoxic, inexpensive, and active against the typical pathogens that can cause surgical site infection postoperatively. To maximize its effectiveness, intravenous perioperative prophylaxis should be administered within 30 to 60 minutes before the surgical incision. Antimicrobial prophylaxis should be of short duration to decrease toxicity and antimicrobial resistance and to reduce cost.

  10. Edwardsiella tarda Ivy, a lysozyme inhibitor that blocks the lytic effect of lysozyme and facilitates host infection in a manner that is dependent on the conserved cysteine residue.

    Science.gov (United States)

    Wang, Chong; Hu, Yong-hua; Sun, Bo-guang; Li, Jun; Sun, Li

    2013-10-01

    Edwardsiella tarda is a Gram-negative bacterial pathogen with a broad host range that includes fish and humans. In this study, we examined the activity and function of the lysozyme inhibitor Ivy (named IvyEt) identified in the pathogenic E. tarda strain TX01. IvyEt possesses the Ivy signature motif CKPHDC in the form of (82)CQPHNC(87) and contains several highly conserved residues, including a tryptophan (W55). For the purpose of virulence analysis, an isogenic TX01 mutant, TXivy, was created. TXivy bears an in-frame deletion of the ivyEt gene. A live infection study in a turbot (Scophthalmus maximus) model showed that, compared to TX01, TXivy exhibited attenuated overall virulence, reduced tissue dissemination and colonization capacity, an impaired ability to replicate in host macrophages, and decreased resistance against the bactericidal effect of host serum. To facilitate functional analysis, recombinant IvyEt (rIvy) and three mutant proteins, i.e., rIvyW55A, rIvyC82S, and rIvyH85D, which bear Ala, Ser, and Asp substitutions at W55, C82, and H85, respectively, were prepared. In vitro studies showed that rIvy, rIvyW55A, and rIvyH85D were able to block the lytic effect of lysozyme on a Gram-positive bacterium, whereas rIvyC82S could not do so. Likewise, rIvy, but not rIvyC82S, inhibited the serum-facilitated killing effect of lysozyme on E. tarda. In vivo analysis showed that rIvy, but not rIvyC82S, restored the lost pathogenicity of TXivy and enhanced the infectivity of TX01. Together these results indicate that IvyEt is a lysozyme inhibitor and a virulence factor that depends on the conserved C82 for biological activity.

  11. Study on combustion characteristics of blended coals

    Energy Technology Data Exchange (ETDEWEB)

    Li Yonghua; Wang Chunbo; Chen Hongwei [North China Electric Power University, Baoding (China)

    2007-02-15

    Power plants in China have to burn blended coal instead of one specific coal for a variety of reasons. So it is of great necessity to investigate the combustion of blended coals. Using a test rig with a capacity of 640 MJ/h with an absolute milling system and flue gas online analysis system, characteristics such as burnout, slag, and pollution of some blended coals were investigated. The ratio of coke and slag as a method of distinguishing coal slagging characteristic was introduced. The results show that the blending of coal has some effect on NOx but there is no obvious rule. SOx emission can be reduced by blending low sulfur coal.

  12. Introducing blended e-learning course design

    DEFF Research Database (Denmark)

    Gyamfi, Samuel Adu; Ryberg, Thomas

    2012-01-01

    In the face of diminishing education budgets in higher education, blended learning has been found to be a viable and effective approach to deliver high-quality, up-to-date, on-demand solutions to developing cross-curricular skills of undergraduates. However, research has also shown that blended...... learning solutions do not often live up to the potential of the approach or fail to produce the intended results because the students are not always equipped to handle the technical, psychological and organisational challenges of blended learning approaches. This project surveyed seventy-five first year...... the students’ e-readiness for an implementation of a blend-ed course design....

  13. Introducing blended e-learning course design

    DEFF Research Database (Denmark)

    Gyamfi, Samuel Adu; Ryberg, Thomas

    2012-01-01

    In the face of diminishing education budgets in higher education, blended learning has been found to be a viable and effective approach to deliver high-quality, up-to-date, on-demand solutions to developing cross-curricular skills of undergraduates. However, research has also shown that blended...... learning solutions do not often live up to the potential of the approach or fail to produce the intended results because the students are not always equipped to handle the technical, psychological and organisational challenges of blended learning approaches. This project surveyed seventy-five first year...... the students’ e-readiness for an implementation of a blend-ed course design....

  14. Antimicrobial effectors in the nematode Caenorhabditis elegans: an outgroup to the Arthropoda.

    Science.gov (United States)

    Dierking, Katja; Yang, Wentao; Schulenburg, Hinrich

    2016-05-26

    Nematodes and arthropods likely form the taxon Ecdysozoa. Information on antimicrobial effectors from the model nematode Caenorhabditis elegans may thus shed light on the evolutionary origin of these defences in arthropods. This nematode species possesses an extensive armory of putative antimicrobial effector proteins, such as lysozymes, caenopores (or saposin-like proteins), defensin-like peptides, caenacins and neuropeptide-like proteins, in addition to the production of reactive oxygen species and autophagy. As C. elegans is a bacterivore that lives in microbe-rich environments, some of its effector peptides and proteins likely function in both digestion of bacterial food and pathogen elimination. In this review, we provide an overview of C. elegans immune effector proteins and mechanisms. We summarize the experimental evidence of their antimicrobial function and involvement in the response to pathogen infection. We further evaluate the microbe-induced expression of effector genes using WormExp, a recently established database for C. elegans gene expression analysis. We emphasize the need for further analysis at the protein level to demonstrate an antimicrobial activity of these molecules both in vitro and in vivoThis article is part of the themed issue 'Evolutionary ecology of arthropod antimicrobial peptides'.

  15. Effect of polyester blends in hydroentangled raw and bleached cotton nonwoven fabrics on the adsorption of alkyl-dimethyl-benzyl-ammonium chloride

    Science.gov (United States)

    The adsorption kinetics and isotherms of alkyl-dimethyl-benzyl-ammonium chloride (ADBAC), a cationic surfactant commonly employed as an antimicrobial agent, on hydroentangled nonwoven fabrics (applicable for wipes) including raw cotton, bleached cotton, and their blends with polyester (PES) were stu...

  16. Uptake and release kinetics of lysozyme in and from an oxidized starch polymer microgel

    NARCIS (Netherlands)

    Li, Y.; Zhang, Z.; Leeuwen, van H.P.; Cohen Stuart, M.A.; Norde, W.; Kleijn, J.M.

    2011-01-01

    The kinetics of uptake and release of fluorescently labeled lysozyme by/from spherical oxidized starch polymer microgel particles (diameter 10–20 µm) was investigated using confocal laser scanning microscopy. Both the protein and the microgel have a pH dependent charge; in the pH range 3–9, the prot

  17. Uptake and release kinetics of lysozyme in and from an oxidized starch polymer microgel

    NARCIS (Netherlands)

    Li, Yuan; Zhang, Zeshi; van Leeuwen, Herman P.; Stuart, Martien A. Cohen; Norde, Willem; Kleijn, J. Mieke

    2011-01-01

    The kinetics of uptake and release of fluorescently labeled lysozyme by/from spherical oxidized starch polymer microgel particles (diameter 10-20 mu m) was investigated using confocal laser scanning microscopy. Both the protein and the microgel have a pH dependent charge; in the pH range 3-9, the pr

  18. Pluronic-lysozyme conjugates as anti-adhesive and antibacterial bifunctional polymers for surface coating

    NARCIS (Netherlands)

    Muszanska, A.K.; Busscher, H.J.; Herrmann, A.; Mei, van der H.C.; Norde, W.

    2011-01-01

    This paper describes the preparation and characterization of polymer protein conjugates composed of a synthetic triblock copolymer with a central polypropylene oxide (PPO) block and two terminal polyethylene oxide (PEO) segments, Pluronic F-127, and the antibacterial enzyme lysozyme attached to the

  19. Pluronic-lysozyme conjugates as anti-adhesive and antibacterial bifunctional polymers for surface coating

    NARCIS (Netherlands)

    Muszanska, Agnieszka K.; Busscher, Henk J.; Herrmann, Andreas; van der Mei, Henny C.; Norde, Willem

    This paper describes the preparation and characterization of polymer protein conjugates composed of a synthetic triblock copolymer with a central polypropylene oxide (PPO) block and two terminal polyethylene oxide (PEO) segments, Pluronic F-127, and the antibacterial enzyme lysozyme attached to the

  20. Lysozyme-magnesium aluminum silicate microparticles: Molecular interaction, bioactivity and release studies

    DEFF Research Database (Denmark)

    Kanjanakawinkul, Watchara; Medlicott, Natalie J.; Rades, Thomas

    2015-01-01

    The objectives of this study were to investigate the adsorption behavior of lysozyme (LSZ) onto magnesium aluminum silicate (MAS) at various pHs and to characterize the LSZ–MAS microparticles obtained from the molecular interaction between LSZ and MAS. The results showed that LSZ could be bound...

  1. Quinopeptide formation associated with the disruptive effect of epigallocatechin-gallate on lysozyme fibrils.

    Science.gov (United States)

    Cao, Na; Zhang, Yu-Jie; Feng, Shuang; Zeng, Cheng-Ming

    2015-01-01

    Numerous studies demonstrate that natural polyphenols can inhibit amyloid formation and disrupt preformed amyloid fibrils. In the present study, the fibril-disruptive effects of epigallocatechin-3-gallate (EGCG) were examined using lysozyme as a model protein. The results indicated that EGCG dose dependently inhibited lysozyme fibrillation and modified the peptide chains with quinonoid moieties under acidic conditions, as measured by ThT fluorescence, transmission electron microscopy, and an NBT-staining assay. Moreover, EGCG transformed the preformed lysozyme fibrils to amorphous aggregates through quinopeptide formation. The thiol blocker, N-ethylmaleimide, inhibited the disruptive effect of EGCG on preformed fibrils, suggesting that thiol groups are the binding sites for EGCG. We propose that the formation of quinone intermediates via oxidation and subsequent binding to lysozyme chains are the main processes driving the inhibition of amyloid formation and disruption of preformed fibrils by EGCG. The information presented in this study may provide fresh insight into the link between the antioxidant capacity and anti-amyloid activity of polyphenols. Copyright © 2015 Elsevier B.V. All rights reserved.

  2. Pluronic-lysozyme conjugates as anti-adhesive and antibacterial bifunctional polymers for surface coating

    NARCIS (Netherlands)

    Muszanska, A.K.; Busscher, H.J.; Herrmann, A.; Mei, van der H.C.; Norde, W.

    2011-01-01

    This paper describes the preparation and characterization of polymer protein conjugates composed of a synthetic triblock copolymer with a central polypropylene oxide (PPO) block and two terminal polyethylene oxide (PEO) segments, Pluronic F-127, and the antibacterial enzyme lysozyme attached to the

  3. The Effect of Ethylene Glycol, Glycine Betaine, and Urea on Lysozyme Thermal Stability

    Science.gov (United States)

    Schwinefus, Jeffrey J.; Leslie, Elizabeth J.; Nordstrom, Anna R.

    2010-01-01

    The four-week student project described in this article is an extension of protein thermal denaturation experiments to include effects of added cosolutes ethylene glycol, glycine betaine, and urea on the unfolding of lysozyme. The transition temperatures and van't Hoff enthalpies for unfolding are evaluated for six concentrations of each cosolute,…

  4. Electron loss from multiply protonated lysozyme ions in high energy collisions with molecular oxygen

    DEFF Research Database (Denmark)

    Hvelplund, P; Nielsen, SB; Sørensen, M

    2001-01-01

    We report on the electron loss from multiply protonated lysozyme ions Lys-Hn(n)+ (n = 7 - 17) and the concomitant formation of Lys-Hn(n+1)+. in high-energy collisions with molecular oxygen (laboratory kinetic energy = 50 x n keV). The cross section for electron loss increases with the charge stat...

  5. Immunohistochemical demonstration of lysozyme in normal, reactive and neoplastic cells of the mononuclear phagocyte system.

    Directory of Open Access Journals (Sweden)

    Motoi,Makoto

    1984-04-01

    Full Text Available Using the peroxidase antiperoxidase (PAP method, lysozyme (LZM was shown to exist in normal, reactive and neoplastic cells belonging to the mononuclear phagocyte system (MPS, but was not detected in histiocytosis X cells. Immunostaining for cytoplasmic LZM by the PAP method is useful for identification of mononuclear phagocytes and for diagnosis of the diseases in which these cells participate.

  6. Specific delivery of captopril to the kidney with the prodrug captopril-lysozyme

    NARCIS (Netherlands)

    Kok, R.J; Moolenaar, Frits; de Zeeuw, D; Meijer, D.K F

    Low-molecular-weight proteins (LMWPs) accumulate in the proximal tubular cells of the kidney, which makes these proteins interesting tools for renal drug targeting. We studied this approach using the LMWP lysozyme as a carrier for the angiotensin-converting enzyme inhibitor captopril. Captopril was

  7. Pr(Ⅲ) and Nd(Ⅲ) Absorption Spectroscopic Probe to Investigate Interaction with Lysozyme (HEW)

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Pr(Ⅲ) and Nd(Ⅲ) can be utilized as absorption spectroscopic probes to investigate the interaction of biomolecules like Lysozyme (HEW) with Ca(Ⅱ) in-vitro; the most abundant metal ion in the human body system. The spectroscopic techniques involving comparative absorption, absorption difference, and quantitative intensity analysis using 4f-4f transitions are utilized for changes in the inner sphere coordination pattern of Pr(Ⅲ) and Nd(Ⅲ) in solution as well as in solid state. The present study deals with an important biomolecule in human metabolism, that is, Lysozyme (HEW). The absorption spectral parameters such as the oscillator strength (P), the Judd-Ofelt (Tλ) intensity parameters, and the Slater-Condon inter electronic parameters are calculated using chi square methods. The obtained results are used to determine the probable geometry of the complex in the solution, the nature of the bond between Pr(Ⅲ)/Nd(Ⅲ) with lysozyme, and the inner sphere coordination environment of f-f transitions. The results obtained from various experimental conditions are utilized to investigate the coordination changes in the Pr(Ⅲ)/Nd(Ⅲ) complexes caused by different coordinating sites of lysozyme, normalized bite, denticity, the solvent nature, the coordination number, the nature of bond and other parameters to mimic the interaction of the Ca(Ⅱ) ion with such biomolecule.

  8. Lysozyme adsorption on the colloidal chromium(III) oxide surface: Its impact on the system stability

    Energy Technology Data Exchange (ETDEWEB)

    Szewczuk-Karpisz, Katarzyna, E-mail: k.szewczuk-karpisz@wp.pl; Wiśniewska, Małgorzata; Myśliwiec, Dawid

    2015-08-30

    Highlights: • Lysozyme adsorption mechanism on the chromium(III) oxide surface was determined. • Surface charge density as well as zeta potential of Cr{sub 2}O{sub 3} particles were measured. • Turbidimetric method was used to estimate the suspension stability. • Depending on the pH value, lysozyme increases or decreases the system stability. - Abstract: This paper describes the lysozyme (LSZ) presence effect on the chromium(III) oxide (Cr{sub 2}O{sub 3}) suspension stability. First, the electrokinetic properties of the examined system, i.e. surface charge density and zeta potential of solid particles in the absence and presence of LSZ, were determined. The lysozyme addition reduces the metal oxide surface charge, which may be related to the interaction of the LSZ protonated amino groups with the adsorbent surface moieties. The LSZ macromolecules undergo adsorption on the Cr{sub 2}O{sub 3} surface only under electrostatic attraction. At the LSZ concentrations above 50 ppm the macromolecules cover completely the particle surface, which is evidenced by the observed zeta potential values. The LSZ influence on the Cr{sub 2}O{sub 3} suspension stability depends on the solution pH value. At pH 3, 4.6 and 7.6, the LSZ addition improves the system stability. In turn, at pH 9 it is associated with the slight suspension destabilization.

  9. Particle-loaded hollow-fiber membrane adsorbers for lysozyme separation

    NARCIS (Netherlands)

    Avramescu, M.E.; Borneman, Zandrie; Wessling, Matthias

    2008-01-01

    The separation of lysozyme (LZ), a valuable enzyme naturally present in chicken egg white, was carried out using a new type of ion exchange hollow-fiber membranes. Functionalities were incorporated into the polymeric membranes by dispersing ion-exchange resins (IERs) in a microporous structure

  10. The Effect of Ethylene Glycol, Glycine Betaine, and Urea on Lysozyme Thermal Stability

    Science.gov (United States)

    Schwinefus, Jeffrey J.; Leslie, Elizabeth J.; Nordstrom, Anna R.

    2010-01-01

    The four-week student project described in this article is an extension of protein thermal denaturation experiments to include effects of added cosolutes ethylene glycol, glycine betaine, and urea on the unfolding of lysozyme. The transition temperatures and van't Hoff enthalpies for unfolding are evaluated for six concentrations of each cosolute,…

  11. Papaya (Carica papaya) lysozyme is a member of the family 19 (Basic, class II) chitinases

    NARCIS (Netherlands)

    Subroto, T; Sufiati, S; Beintema, JJ

    1999-01-01

    The most comprehensive studies on a plant lysozyme (EC 3.2.1.17) are those on the enzyme from papaya (Carica papaya) latex, published in 1967 and 1969. However, the N-terminal amino acid sequence of five amino acid sequence of this enzyme, determined by manual Edman degradation, did not allow assign

  12. Solvent-induced lysozyme gels: rheology, fractal analysis, and sol-gel kinetics.

    Science.gov (United States)

    da Silva, Marcelo A; Arêas, Elizabeth P G

    2005-09-15

    In this work, the gelation kinetics and fractal character of lysozyme gel matrices developed in tetramethylurea (TMU)-water media were investigated. Gelation times were determined from the temporal crossover point between the storage, G', and loss, G'', moduli, as a function of the binary solvent composition and of protein concentration. The inverse dependence of the upper limit of the linear viscoelastic region (gamma0) on protein concentration indicate that the lysozyme gels belong to the "strong link" kind, a gel category where interparticle links are stronger than intraparticle ones. Lysozyme gel fractal dimensions (Df) were determined from the analysis of rheological data according to a scaling theory by Shih et al. [Phys. Rev. A 42 (1990) 4772-4779] and were found to be compatible with a diffusion-limited cluster-aggregation kinetics (DLCA) for lysozyme gels formed at the TMU mass fraction in the binary organic-aqueous solvent, wTMU=0.9, and with a reaction-limited cluster aggregation kinetics (RLCA) for wTMU in the 0.6< or =wTMU< or =0.8 range.

  13. Renal-selective delivery and angiotensin-converting enzyme inhibition by subcutaneously administered captopril-lysozyme

    NARCIS (Netherlands)

    Prakash, Jai; van Loenen - Weemaes, Anne-miek; Haas, M; Proost, Hans; Meijer, D.K F; Moolenaar, Frits; Poelstra, Klaas; Kok, R.J

    In previous studies, we have demonstrated that the low molecular weight protein lysozyme can be used as a renal-selective drug carrier for delivery of the angiotensin-converting enzyme ( ACE) inhibitor captopril. Typically, such macromolecular drug-targeting preparations are administered

  14. Study on flow characteristics of solid/liquid system in lysozyme crystal growth

    Institute of Scientific and Technical Information of China (English)

    CUI HaiLiang; YU Yong; CHEN WanChun; KANG Qi

    2007-01-01

    During the process of lysozyme protein crystallization with batch method, the macroscopic flow field of solid/liquid system was observed by particle image velocimetry (PIV). Furthermore, a normal growth rate of (110) face and local flow field around a single protein crystal were obtained by a long work distance microscope. The experimental results showed that the average velocity, the maximal velocity of macroscopic solid/liquid system and the velooity of local flow field around single protein crystal were fluctuant. The effective boundary layer thickness δeff, the concentration at the interface Gi and the characteristic velocity V were calculated using a convection-diffusion model. The results showed that the growth of lysozyme crystal in this experiment was dominated by interfacial kinetics rather than bulk transport, and the function of buoyancy-driven flow in bulk transport was small, however, the effect of bulk transport in crystal growth had a tendency to increase with the increase of lysozyme concentration. The calculated results also showed that the order of magnitude of shear force was about 10-21 N,which was much less than the bond force between the lysozyme molecules. Therefore the shear force induced by buoyancy-driven flows cannot remove the protein molecules from the interface of crystal.

  15. Expression of recombinant human lysozyme in the milk of transgenic mice

    Institute of Scientific and Technical Information of China (English)

    YU Zhengquan; FAN Baoliang; DAI Yunping; ZHENG Ming; NIU Huiling; WANG Meili; WANG Lili; FEI Jing; LI Ning

    2003-01-01

    Human lysozyme is a 130-aa (amino acid) alkaline polypeptide, and has both anti-bacterial and anti-viral properties which make it an important component of human natural immunity system. As a first step toward the ultimate goal ofimproving the anti-bacterial properties of bovine and ovine milk, a transgenic mouse that contains the genomic DNA sequence of the human lysozme gene has been generated for the first time. From 83 mice generated by microinjection, a total of 6 positive transgenic mice were identified by PCR and Southern blot. F1 mice positive for transgene in lines were also detected by PCR. This shows that transgene could be transmitted from founder transgenic mice to their offspring. Recombinant human lysozyme (rHlys) was found in the whey of 3 female positive transgenic mice by Western blot. The highest concentration of rHlys for transgenic micewas 0.2 mg/mL. The antibacterial activity of the whey for transgenic mice was highly enhanced up to 0.4 times as much as that of human, while that of non-transgenic mouse was very low. Although the lysozyme activity of transgenic mice is still lower than that of human, the rHlys exhibits the same specific activity as that of human lysozyme. It provides a strong basis for further studies into the possible application of rHlys express in mammary gland.

  16. Lysozyme Thermal Denaturation and Self-Interaction: Four Integrated Thermodynamic Experiments for the Physical Chemistry Laboratory

    Science.gov (United States)

    Schwinefus, Jeffrey J.; Schaefle, Nathaniel J.; Muth, Gregory W.; Miessler, Gary L.; Clark, Christopher A.

    2008-01-01

    As part of an effort to infuse our physical chemistry laboratory with biologically relevant, investigative experiments, we detail four integrated thermodynamic experiments that characterize the denaturation (or unfolding) and self-interaction of hen egg white lysozyme as a function of pH and ionic strength. Students first use Protein Explorer to…

  17. Uptake and release kinetics of lysozyme in and from an oxidized starch polymer microgel

    NARCIS (Netherlands)

    Li, Y.; Zhang, Z.; Leeuwen, van H.P.; Cohen Stuart, M.A.; Norde, W.; Kleijn, J.M.

    2011-01-01

    The kinetics of uptake and release of fluorescently labeled lysozyme by/from spherical oxidized starch polymer microgel particles (diameter 10–20 µm) was investigated using confocal laser scanning microscopy. Both the protein and the microgel have a pH dependent charge; in the pH range 3–9, the prot

  18. Uptake and release kinetics of lysozyme in and from an oxidized starch polymer microgel

    NARCIS (Netherlands)

    Li, Yuan; Zhang, Zeshi; van Leeuwen, Herman P.; Stuart, Martien A. Cohen; Norde, Willem; Kleijn, J. Mieke

    2011-01-01

    The kinetics of uptake and release of fluorescently labeled lysozyme by/from spherical oxidized starch polymer microgel particles (diameter 10-20 mu m) was investigated using confocal laser scanning microscopy. Both the protein and the microgel have a pH dependent charge; in the pH range 3-9, the pr

  19. Mechanic Insight into Aggregation of Lysozyme by Ultrasensitive Differential Scanning Calorimetry and Sedimentation Velocity.

    Science.gov (United States)

    Wu, Sha; Ding, Yanwei; Zhang, Guangzhao

    2015-12-31

    Folding and aggregation of proteins profoundly influence their functions. We have investigated the effects of thermal history, concentration and pH on the denaturation and refolding of lysozyme by using ultrasensitive differential scanning calorimetry (US-DSC) and sedimentation velocity (SV) via analytical ultracentrifugation (AUC). The former is sensitive to small energy change whereas the latter can differentiate the oligomers such as dimer and trimer from individual protein molecules. Our studies reveal that the degree of denaturation irreversibility increases as heating times increases. The denaturation temperature (Td) and enthalpy change (ΔH) are influenced by heating rate since the denaturation is not in equilibrium during the heating. We can obtain Td and ΔH in equilibrium by extrapolation of heating rate to zero. In a dilute solution, no aggregation but unfolding happens in the denaturation. However, when the concentration is above a critical value (∼15.0 mg/mL), lysozyme molecules readily form trimers or other oligomers. Lysozyme molecules unfold into stretched chains at pH > 6.0, which would further forms large aggregates. The formation of aggregates makes the refolding of lysozyme impossible.

  20. Behavior of lysozyme adsorbed onto biological liquid crystal lipid monolayer at the air/water interface

    Science.gov (United States)

    Lu, Xiaolong; Shi, Ruixin; Hao, Changchun; Chen, Huan; Zhang, Lei; Li, Junhua; Xu, Guoqing; Sun, Runguang

    2016-09-01

    The interaction between proteins and lipids is one of the basic problems of modern biochemistry and biophysics. The purpose of this study is to compare the penetration degree of lysozyme into 1,2-diapalmitoyl-sn-glycero-3-phosphocholine (DPPC) and 1,2-dipalmitoyl-sn-glycero-3-phosphoethano-lamine (DPPE) by analyzing the data of surface pressure-area (π-A) isotherms and surface pressure-time (π-T) curves. Lysozyme can penetrate into both DPPC and DPPE monolayers because of the increase of surface pressure at an initial pressure of 15 mN/m. However, the changes of DPPE are larger than DPPC, indicating stronger interaction of lysozyme with DPPE than DPPC. The reason may be due to the different head groups and phase state of DPPC and DPPE monolayers at the surface pressure of 15 mN/m. Atomic force microscopy reveals that lysozyme was absorbed by DPPC and DPPE monolayers, which leads to self-aggregation and self-assembly, forming irregular multimers and conical multimeric. Through analysis, we think that the process of polymer formation is similar to the aggregation mechanism of amyloid fibers. Project supported by the National Natural Science Foundation of China (Grant Nos. 21402114 and 11544009), the Natural Science Basic Research Plan in Shaanxi Province of China (Grant No. 2016JM2010), the Fundamental Research Funds for the Central Universities of China (Grant No. GK201603026), and the National University Science and Technology Innovation Project of China (Grant No. 201610718013).

  1. Pulsed laser deposition of the lysozyme protein: an unexpected “Inverse MAPLE” process

    DEFF Research Database (Denmark)

    Schou, Jørgen; Matei, Andreea; Constantinescu, Catalin

    2012-01-01

    the ejection and deposition of lysozyme. This can be called an “inverse MAPLE” process, since the ratio of “matrix” to film material in the target is 10:90, which is inverse of the typical MAPLE process where the film material is dissolved in the matrix down to several wt.%. Lysozyme is a well-known protein...... which is used in food processing and is also an important constituent of human secretions such as sweat and saliva. It has a well-defined mass (14307 u) and can easily be detected by mass spectrometric methods such as MALDI (Matrix-assisted laser desorption ionization) in contrast to many other organic...... materials. Also, the thermal properties of lysozyme, including the heat-induced decomposition behavior are comparatively well-known. The ablation of lysozyme from a dry pressed target in vacuum was measured by weight loss in nanosecond laser ablation at 355 with a fluence of 0.5 to 6 J/cm2. Films...

  2. Lysozyme-mediated biomineralization of titanium-tungsten oxide hybrid nanoparticles with high photocatalytic activity.

    Science.gov (United States)

    Kim, Jung Kyu; Jang, Ji-ryang; Choi, Noori; Hong, Dahyun; Nam, Chang-Hoon; Yoo, Pil J; Park, Jong Hyeok; Choe, Woo-Seok

    2014-10-21

    Titanium-tungsten oxide composites with greatly enhanced photocatalytic activity were synthesized by lysozyme-mediated biomineralization. It was shown for the first time that simple control of the onset of biomineralization could enable fine tuning of the composition and crystallinity of the composites to determine their photocatalytic performance.

  3. Identification of salivary proteins at oil–water interfaces stabilized by lysozyme and ß-lactoglobulin

    NARCIS (Netherlands)

    Silletti, E.; Vitorino, R.M.P.; Schipper, R.G.; Amado, F.M.L.; Vingerhoeds, M.H.

    2010-01-01

    In this research, we investigated the interaction occurring between oil-in-water emulsion droplets, stabilized by different emulsifiers, i.e. lysozyme and ß-lactoglobulin (ß-lg), and salivary proteins (SPs) with a molecular mass (Mr) above about 10 kDa. Different techniques, i.e. infrared

  4. In vitro antimicrobial activity of total extracts of the leaves of Petiveria alliacea L. (Anamu

    Directory of Open Access Journals (Sweden)

    Ania Ochoa Pacheco

    2013-06-01

    Full Text Available The antimicrobial activity of 13 total extracts was evaluated, 10 soft extracts (B and 3 blended extracts (E prepared from dry and fresh leaves of Petiveria alliacea L. Various solvents were used for their preparation: hydroalcoholic solution at 30%, 80% and isopropyl alcohol. The antimicrobial effect of the extracts was tested by means of the method of Kirby-Bauer, using four bacterial strains from the ATCC collection (Escherichia coli, Staphylococcus aureus, Enterococcus faecalis and Pseudomonas aeruginosa and a leveduriform fungus (Candida albicans. The following quality control parameters were determined for most active extracts: physical, physical-chemical and chemical parameters. The results were: nine extracts showed antibacterial activity, being the most concentrated (B8 and E3, the ones with the highest activity in the presence of the bacteria tested; the effect of blended extracts (E1, E2 and E3 was greater in the presence of P. aeruginosa. Blended extracts are considered more potent and active than soft extracts. No antifungal activity was obtained for both types of extracts. The Minimum Inhibitory Concentration (MIC and Minimum Bactericidal Concentration (MBC were determined for both extracts, with the following results: MIC-soft extracts (>100 mg/mL, blended extracts (>50 mg/mL; MBC-soft extracts (≥400 mg/mL, blended extracts (≥200 mg/mL based on fresh leaves.

  5. Fast disinfecting antimicrobial surfaces.

    Science.gov (United States)

    Madkour, Ahmad E; Dabkowski, Jeffery M; Nusslein, Klaus; Tew, Gregory N

    2009-01-20

    Silicon wafers and glass surfaces were functionalized with facially amphiphilic antimicrobial copolymers using the "grafting from" technique. Surface-initiated atom transfer radical polymerization (ATRP) was used to grow poly(butylmethacrylate)-co-poly(Boc-aminoethyl methacrylate) from the surfaces. Upon Boc-deprotection, these surfaces became highly antimicrobial and killed S. aureus and E. coli 100% in less than 5 min. The molecular weight and grafting density of the polymer were controlled by varying the polymerization time and initiator surface density. Antimicrobial studies showed that the killing efficiency of these surfaces was independent of polymer layer thickness or grafting density within the range of surfaces studied.

  6. Involvement of PKA, PKC, and Ca2+ in LPS-activated expression of the chicken lysozyme gene.

    Science.gov (United States)

    Regenhard, P; Goethe, R; Phi-van, L

    2001-04-01

    The lysozyme gene is activated in myelomonocytic HD11 cells in response to LPS. In this study, we described the involvement of LPS-activated signal transduction pathways in activation of the lysozyme gene. Pre-treatment of HD 11 cells with H-89, H-7, TMB-8, or KN-93 resulted in inhibition of the LPS-enhanced lysozyme expression, suggesting that PKA, PKC, and Ca2+-dependent protein kinases participate in the LPS activation. CaMKII seems to be required for the processing of lysozyme transcripts. TPA and calcium ionophore A23187, when separately added to HD11 cells, stimulated the lysozyme expression effectively, and forskolin was ineffective. It is interesting that simultaneous treatment of cells with forskolin and calcium ionophore A23187 resulted in a potentiated increase in lysozyme mRNA expression, indicating a synergistic cooperation of PKA and Ca2+. This synergistic effect of PKA and Ca2+ was observed on the expression of a stably integrated CAT construct, controlled by the lysozyme promoter and the -6.1-kb enhancer containing binding sites for C/EBP and NF-kappaB/Rel. Therefore, we discussed the role of C/EBPbeta(NF-M), CREB, and NF-kappaB/Rel as possible targets for phosphorylation mediated by PKA, PKC, and Ca2+.

  7. Covalent immobilization of lysozyme onto woven and knitted crimped polyethylene terephthalate grafts to minimize the adhesion of broad spectrum pathogens

    Energy Technology Data Exchange (ETDEWEB)

    Al Meslmani, Bassam M., E-mail: almeslmanib@yahoo.com [Department of Pharmaceutical Technology and Biopharmaceutics, Marburg University, Ketzerbach 63, 35037 Marburg (Germany); Mahmoud, Gihan F., E-mail: mahmoudg@staff.uni-marburg.de [Department of Pharmaceutical Technology and Biopharmaceutics, Marburg University, Ketzerbach 63, 35037 Marburg (Germany); Department of Pharmaceutics and Industrial Pharmacy, Helwan University, Ain Helwan, 11795 Cairo (Egypt); Leichtweiß, Thomas, E-mail: Thomas.Leichtweiss@phys.Chemie.uni-giessen.de [Institute of Physical Chemistry, Justus-Liebig-University Giessen, Heinrich-Buff-Ring 58, 35392 Giessen (Germany); Strehlow, Boris, E-mail: strehlo4@staff.uni-marburg.de [Department of Pharmaceutical Technology and Biopharmaceutics, Marburg University, Ketzerbach 63, 35037 Marburg (Germany); Sommer, Frank O., E-mail: sommerf@med.uni-marburg.de [Institute for Medical Microbiology and Hospital Hygiene, Marburg University, Hans Meerwein Str 2, 35032 Marburg (Germany); Lohoff, Michael D., E-mail: lohoff@med.uni-marburg.de [Institute for Medical Microbiology and Hospital Hygiene, Marburg University, Hans Meerwein Str 2, 35032 Marburg (Germany); Bakowsky, Udo, E-mail: ubakowsky@aol.com [Department of Pharmaceutical Technology and Biopharmaceutics, Marburg University, Ketzerbach 63, 35037 Marburg (Germany)

    2016-01-01

    Graft-associated infections entirely determine the short-term patency of polyethylene terephthalate PET cardiovascular graft. We attempted to enzymatically inhibit the initial bacterial adhesion to PET grafts using lysozyme. Lysozyme was covalently immobilized onto woven and knitted forms of crimped PET grafts by the end-point method. Our figures of merit revealed lysozyme immobilization yield of 15.7 μg/cm{sup 2}, as determined by the Bradford assay. The activity of immobilized lysozyme on woven and knitted PET manifested 58.4% and 55.87% using Micrococcus lysodeikticus cells, respectively. Noteworthy, the adhesion of vein catheter-isolated Staphylococcus epidermidis decreased by 6- to 8-folds and of Staphylococcus aureus by 11- to 12-folds, while the Gram-negative Escherichia coli showed only a decrease by 3- to 4-folds. The anti-adhesion efficiency was specific for bacterial cells and no significant effect was observed on adhesion and growth of L929 cells. In conclusion, immobilization of lysozyme onto PET grafts can inhibit the graft-associated infection. - Highlights: • Lysozyme was covalently immobilized on crimped polyethylene terephthalate (PET). • The activity of immobilized lysozyme was meaningfully reduced. • The maintained activity significantly declined the adhesion of Gram-positive stains. • The enzymatic anti-adhesion efficiency reported lesser extent against Gram-negative. • The anti-bacterial activity displayed no significant effect on cells compatibility.

  8. Molecular cloning, sequence analysis and phylogeny of first caudata g-type lysozyme in axolotl (Ambystoma mexicanum).

    Science.gov (United States)

    Yu, Haining; Gao, Jiuxiang; Lu, Yiling; Guang, Huijuan; Cai, Shasha; Zhang, Songyan; Wang, Yipeng

    2013-11-01

    Lysozymes are key proteins that play important roles in innate immune defense in many animal phyla by breaking down the bacterial cell-walls. In this study, we report the molecular cloning, sequence analysis and phylogeny of the first caudate amphibian g-lysozyme: a full-length spleen cDNA library from axolotl (Ambystoma mexicanum). A goose-type (g-lysozyme) EST was identified and the full-length cDNA was obtained using RACE-PCR. The axolotl g-lysozyme sequence represents an open reading frame for a putative signal peptide and the mature protein composed of 184 amino acids. The calculated molecular mass and the theoretical isoelectric point (pl) of this mature protein are 21523.0 Da and 4.37, respectively. Expression of g-lysozyme mRNA is predominantly found in skin, with lower levels in spleen, liver, muscle, and lung. Phylogenetic analysis revealed that caudate amphibian g-lysozyme had distinct evolution pattern for being juxtaposed with not only anura amphibian, but also with the fish, bird and mammal. Although the first complete cDNA sequence for caudate amphibian g-lysozyme is reported in the present study, clones encoding axolotl's other functional immune molecules in the full-length cDNA library will have to be further sequenced to gain insight into the fundamental aspects of antibacterial mechanisms in caudate.

  9. Efficient purification of lysozyme from egg white by 2-mercapto-5-benzimidazolesulfonic acid modified Fe3O4/Au nanoparticles.

    Science.gov (United States)

    Zhu, Xinjun; Zhang, Lianying; Fu, Aiyun; Yuan, Hao

    2016-02-01

    2-Mercapto-5-benzimidazolesulfonic acid (MBISA) modified Fe3O4/Au nanoparticles were synthesized in aqueous solution and characterized by photo correlation spectroscopy (PCS) and vibrating sample magnetometer (VSM). The so-obtained Fe3O4/Au-MBISA nanoparticles were capable of specific adsorbing lysozyme. The maximum amount of lysozyme adsorbed on 1.0mg Fe3O4/Au-MBISA nanoparticles was 346μg. The lysozyme desorption behavior was studied and the lysozyme recovery from Fe3O4/Au-MBISA nanoparticles approached 100% under optimal conditions, and the reusability studies showed that the nanoparticles could maintain about 91% of the initial lysozyme adsorption capacity after 7 repeated adsorption-elution cycles. The Fe3O4/Au-MBISA nanoparticles were used in the purification of lysozyme from chicken egg white, which was verified by a single SDS-PAGE band. Therefore, the obtained Fe3O4/Au-MBISA nanoparticles exhibited excellent performance in the direct purification of lysozyme from egg white.

  10. Observing lysozyme's closing and opening motions by high-resolution single-molecule enzymology.

    Science.gov (United States)

    Akhterov, Maxim V; Choi, Yongki; Olsen, Tivoli J; Sims, Patrick C; Iftikhar, Mariam; Gul, O Tolga; Corso, Brad L; Weiss, Gregory A; Collins, Philip G

    2015-06-19

    Single-molecule techniques can monitor the kinetics of transitions between enzyme open and closed conformations, but such methods usually lack the resolution to observe the underlying transition pathway or intermediate conformational dynamics. We have used a 1 MHz bandwidth carbon nanotube transistor to electronically monitor single molecules of the enzyme T4 lysozyme as it processes substrate. An experimental resolution of 2 μs allowed the direct recording of lysozyme's opening and closing transitions. Unexpectedly, both motions required 37 μs, on average. The distribution of transition durations was also independent of the enzyme's state: either catalytic or nonproductive. The observation of smooth, continuous transitions suggests a concerted mechanism for glycoside hydrolysis with lysozyme's two domains closing upon the polysaccharide substrate in its active site. We distinguish these smooth motions from a nonconcerted mechanism, observed in approximately 10% of lysozyme openings and closings, in which the enzyme pauses for an additional 40-140 μs in an intermediate, partially closed conformation. During intermediate forming events, the number of rate-limiting steps observed increases to four, consistent with four steps required in the stepwise, arrow-pushing mechanism. The formation of such intermediate conformations was again independent of the enzyme's state. Taken together, the results suggest lysozyme operates as a Brownian motor. In this model, the enzyme traces a single pathway for closing and the reverse pathway for enzyme opening, regardless of its instantaneous catalytic productivity. The observed symmetry in enzyme opening and closing thus suggests that substrate translocation occurs while the enzyme is closed.

  11. SCATTERING FUNCTION OF POLYMER BLENDS

    Institute of Scientific and Technical Information of China (English)

    Lin-ping Ke; Mei-li Guo; De-lu Zhao

    2004-01-01

    For a system of flexible polymer molecules, the concepts of two concentrations, namely the segmental and the molecular concentrations, have been proposed in this paper. The former is equivalent to the volume fraction. The latter can be defined as the number of the gravity centers of macromolecules in a unit volume. The two concentrations should be correlated with each other by the conformational function of the polymer chain and should be discussed in different thermodynamic equations. On the basis of these concepts it has been proved that the Flory-Huggins entropy of mixing should be the result of the mixing "ideal gases of the gravity centers of macromolecules". The general correlation between the free energy of mixing and the scattering function (structural factor) of polymer blends has been studied based on the general fluctuation theory. When the Flory-Huggins free energy of mixing is adopted, the de Gennes scattering function of a polymer blend can be derived.

  12. Evaporation characteristics of ETBE-blended gasoline.

    Science.gov (United States)

    Okamoto, Katsuhiro; Hiramatsu, Muneyuki; Hino, Tomonori; Otake, Takuma; Okamoto, Takashi; Miyamoto, Hiroki; Honma, Masakatsu; Watanabe, Norimichi

    2015-04-28

    To reduce greenhouse gas emissions, which contribute to global warming, production of gasoline blended with ethyl tert-buthyl ether (ETBE) is increasing annually. The flash point of ETBE is higher than that of gasoline, and blending ETBE into gasoline will change the flash point and the vapor pressure. Therefore, it is expected that the fire hazard caused by ETBE-blended gasoline would differ from that caused by normal gasoline. The aim of this study was to acquire the knowledge required for estimating the fire hazard of ETBE-blended gasoline. Supposing that ETBE-blended gasoline was a two-component mixture of gasoline and ETBE, we developed a prediction model that describes the vapor pressure and flash point of ETBE-blended gasoline in an arbitrary ETBE blending ratio. We chose 8-component hydrocarbon mixture as a model gasoline, and defined the relation between molar mass of gasoline and mass loss fraction. We measured the changes in the vapor pressure and flash point of gasoline by blending ETBE and evaporation, and compared the predicted values with the measured values in order to verify the prediction model. The calculated values of vapor pressures and flash points corresponded well to the measured values. Thus, we confirmed that the change in the evaporation characteristics of ETBE-blended gasoline by evaporation could be predicted by the proposed model. Furthermore, the vapor pressure constants of ETBE-blended gasoline were obtained by the model, and then the distillation curves were developed.

  13. Antimicrobial activity and partial characterization of bacteriocin-like inhibitory substances produced by Lactobacillus spp. isolated from artisanal Mexican cheese.

    Science.gov (United States)

    Heredia-Castro, Priscilia Y; Méndez-Romero, José I; Hernández-Mendoza, Adrián; Acedo-Félix, Evelia; González-Córdova, Aarón F; Vallejo-Cordoba, Belinda

    2015-12-01

    Lactobacillus spp. from Mexican Cocido cheese were shown to produce bacteriocin-like substances (BLS) active against Staphylococcus aureus,Listeria innocua,Escherichia coli, andSalmonella typhimurium by using the disk diffusion method. Crude extracts of Lactobacillus fermentum showed strong inhibitory activity against Staph. aureus, L. innocua, E. coli, and Salmonella cholerae. Complete inactivation of antimicrobial activity was observed after treatment of crude extracts with proteinase K, pronase, papain, trypsin, and lysozyme, confirming their proteinaceous nature. However, antimicrobial activity was partly lost for some of the crude extracts when treated with α-amylase, indicating that carbohydrate moieties were involved. The antimicrobial activity of the crude extracts was stable at 65°C for 30min over a wide pH range (2-8), and addition of potassium chloride, sodium citrate, ethanol, and butanol did not affect antibacterial activity. However, antimicrobial activity was lost after heating at 121°C for 15min, addition of methanol or Tween 80. Fourteen out of 18 Lactobacillus spp. showed antimicrobial activity against different test microorganisms, and 12 presented bacteriocin-like substances. Generation time and growth rate parameters indicated that the antimicrobial activity of crude extracts from 3 different strains was effective against the 4 indicator microorganisms. One of the crude extracts showed inhibition not only against gram-positive but also against gram-negative bacteria. Bacteriocin-like substances produced by this specific Lactobacillus strain showed potential for application as a food biopreservative.

  14. Pharmacogenomics of antimicrobial agents.

    Science.gov (United States)

    Aung, Ar Kar; Haas, David W; Hulgan, Todd; Phillips, Elizabeth J

    2014-01-01

    Antimicrobial efficacy and toxicity varies between individuals owing to multiple factors. Genetic variants that affect drug-metabolizing enzymes may influence antimicrobial pharmacokinetics and pharmacodynamics, thereby determining efficacy and/or toxicity. In addition, many severe immune-mediated reactions have been associated with HLA class I and class II genes. In the last two decades, understanding of pharmacogenomic factors that influence antimicrobial efficacy and toxicity has rapidly evolved, leading to translational success such as the routine use of HLA-B*57:01 screening to prevent abacavir hypersensitivity reactions. This article examines recent advances in the field of antimicrobial pharmacogenomics that potentially affect treatment efficacy and toxicity, and challenges that exist between pharmacogenomic discovery and translation into clinical use.

  15. Animation of Antimicrobial Resistance

    Medline Plus

    Full Text Available ... showing how bacterial antimicrobial resistance can develop and spread. All FDA CVM produced material may be copied, ... Displays About NARMS Partners in Antibiotic Resistance and Food Safety Bacteria Tested NARMS at Work Meetings and ...

  16. Novel antimicrobial textiles

    Science.gov (United States)

    Cho, Unchin

    2003-10-01

    Many microorganisms can survive, and perhaps proliferate on textiles, generating adverse effects such as: disease transmission, odor generation, pH changes, staining, discoloration and loss of performance. These adverse effects may threaten users' health, deteriorate textile properties and degrade service quality. It may, therefore, be desirable to incorporate antimicrobials on textiles for controlling the growth of microorganisms. This dissertation focuses on the development of antimicrobial fibers and fabrics by integration of antimicrobials with these textiles. The applications of hydantoin-based halamines were mainly investigated in the research. The typical process is that hydantoin containing compounds are grafted onto textiles and transformed to halamine by chlorination. Hydantoin-based halamines are usually chloramines that release chlorine (Cl+) via cleavage of the -NCl functional group which attacks and kills microbes. The antimicrobial behavior is rechargeable many times by rinsing the fiber or fabric with chlorine-containing solution. Some quaternary ammonium type antimicrobials were also investigated in this research. The choice of integrating techniques is dependant on both the textile and antimicrobial compounds. In this dissertation, the nine approaches were studied for incorporating antimicrobial with various textiles: (1) co-extrusion of fibers with halamine precursor additive; (2) grafting of the quaternary ammonium compounds onto ethylene-co-acrylic acid fiber for creating quaternary ammonium type antimicrobial fiber; (3) entrapment of the additives in thermally bonded bicomponent nonwoven fabrics; (4) attaching antimicrobial additives to surfaces with latex adhesive coating; (5) grafting of antimicrobial compounds onto rubber latex via UV exposure; (6) reaction of halamine with needle-punched melamine formaldehyde nonwoven fabric and laminates; (7) coating melamine resin onto tent fabrics and laminates; (8) synthesis of super absorbent polymer

  17. The affect of Pseudomonas aeruginosa ingestion on antimicrobial peptide (AMP) and lysozyme expression in the common housefly (Musca domestica L.)

    Science.gov (United States)

    The common house fly (Musca domestica L.) lives and thrives in one of the most septic niches on Earth, making bacterial exposure imminent. House flies often ingest bacteria and have both physical and chemical defenses utilized to protect themselves from harmful microbes. For example, defense molecul...

  18. Salmonella and Campylobacter reduction and quality characteristics of poultry carcasses treated with various antimicrobials in a post-chill immersion tank.

    Science.gov (United States)

    Nagel, G M; Bauermeister, L J; Bratcher, C L; Singh, M; McKee, S R

    2013-08-01

    Innovations in poultry processing include implementation of antimicrobials in post-chill decontamination tanks. In this study, a total of 160 broiler carcasses were analyzed to evaluate the efficacy of five post-chill water treatments consisting of 0.004% (40ppm) total chlorine, 0.04% (400ppm) or 0.1% (1000ppm) peracetic acid (PAA), and 0.1% (1000ppm) or 0.5% (5000ppm) lysozyme against Salmonella and Campylobacter spp. In addition, sensory analysis was performed to evaluate any associated effects of the antimicrobials on quality attributes of chicken breast meat. Treatment with 0.04% and 0.1% PAA was most effective (P≤0.05) in reducing populations of Salmonella and Campylobacter as compared to the chlorine treatment at 0.004% and lysozyme treatments at 0.1% and 0.5%, as well as the water treatment and the positive control. Treatment with the various antimicrobials was not found to have negative (P≤0.05) impacts on sensory attributes. Results from this study suggest that utilizing PAA as an antimicrobial in a post-chill immersion tank is an effective application for reducing Salmonella and Campylobacter on carcasses while maintaining product quality.

  19. Game innovation through conceptual blending

    DEFF Research Database (Denmark)

    Möring, Sebastian Martin

    In  this  paper  I  wish  to  apply implications of  the  Conceptual  Blending  Theory  to  computer  games.  I  will  analyze  chosen  examples  and  discuss  them  as  a  result  of  video  game  innovation  made  possible  through  "conceptual  blending."  Conceptual  blending  links  at  least......  integration  network  consisting  of  at  least  two  input  spaces,  a  generic  space  and  a  blended  space  as  well  as  its  governing  principles  consisting  of  composition,  completion,  and  elaboration.  With  the  help  of  these  instruments  I  analyze computer  games like  Tuper  Tario  Tros.......,  Hell.  The  purpose  of  my  approach  is  not  so  much  to  validate  the  ideas  of  conceptual  blending  theory  through  another  field  of  examples  (computer  games)  but  to  name  and analyze characteristics of the mentioned games with the  help of a given method....

  20. Game innovation through conceptual blending

    DEFF Research Database (Denmark)

    Möring, Sebastian Martin

    In  this  paper  I  wish  to  apply implications of  the  Conceptual  Blending  Theory  to  computer  games.  I  will  analyze  chosen  examples  and  discuss  them  as  a  result  of  video  game  innovation  made  possible  through  "conceptual  blending."  Conceptual  blending  links  at  least.......,  Hell.  The  purpose  of  my  approach  is  not  so  much  to  validate  the  ideas  of  conceptual  blending  theory  through  another  field  of  examples  (computer  games)  but  to  name  and analyze characteristics of the mentioned games with the  help of a given method.......  integration  network  consisting  of  at  least  two  input  spaces,  a  generic  space  and  a  blended  space  as  well  as  its  governing  principles  consisting  of  composition,  completion,  and  elaboration.  With  the  help  of  these  instruments  I  analyze computer  games like  Tuper  Tario  Tros...

  1. Correspondence Theory and Phonological Blending in French

    Directory of Open Access Journals (Sweden)

    Lee Scott

    2014-07-01

    Full Text Available Though less productive than rival word-formation processes like compounding and affixation, blending is still a rich source of neologisms in French. Despite this productivity, however, blends are often seen by scholars as unpredictable, uninteresting, or both. This analysis picks up where recent studies of blending have left off, using Correspondence Theory and a bundle of segmental constraints to deal with this phenomenon as it pertains to French. More specifically, it shows that blending is the result of a single output standing in correspondence with two or more other outputs, and that we do not need to refer to prosodic information, which is crucial in accounts of blending in languages with lexical stress like English, to account for the process in French. The analysis also differs from previous studies in that it locates blending exclusively within the phonology, leaving its morphological and semantic characteristics to be handled by other processes in the grammar.

  2. Shifts in bacterial communities of eggshells and antimicrobial activities in eggs during incubation in a ground-nesting passerine.

    Directory of Open Access Journals (Sweden)

    Stéphanie Grizard

    Full Text Available Microbial invasion of egg contents is a cause of embryonic death. To counter infection risks, the embryo is protected physically by the eggshell and chemically by antimicrobial proteins. If microbial pressure drives embryo mortality, then females may have evolved, through natural selection, to adapt their immune investment into eggs. Although frequently hypothesized, this match between immune allocation and microorganisms has not been explored yet. To examine if correlations between microbes on eggs and immunity in eggs exist, we collected eggs from red-capped larks (Calandrella cinerea and simultaneously examined their bacterial communities and antimicrobial components--pH, lysozyme and ovotransferrin--during natural incubation. Using molecular techniques, we find that bacterial communities are highly dynamic: bacterial abundance increases from the onset to late incubation, Shannon's α-diversity index increases during early incubation stages, and β-diversity analysis shows that communities from 1 day-old clutches are phylogenetically more similar to each other than the older ones. Regarding the antimicrobials, we notice a decrease of pH and lysozyme concentration, while ovotransferrin concentration increases during incubation. Interestingly, we show that two eggs of the same clutch share equivalent immune protection, independent of clutch age. Lastly, our results provide limited evidence of significant correlation between antimicrobial compounds and bacterial communities. Our study examined simultaneously, for the first time in a wild bird, the dynamics of bacterial communities present on eggshells and of albumen-associated antimicrobial components during incubation and investigated their relationship. However, the link between microorganisms and immunity of eggs remains to be elucidated further. Identifying invading microbes and their roles in embryo mortality, as well as understanding the role of the eggshell microbiome, might be key to

  3. Evaporation characteristics of ETBE-blended gasoline

    Energy Technology Data Exchange (ETDEWEB)

    Okamoto, Katsuhiro, E-mail: okamoto@nrips.go.jp [National Research Institute of Police Science, 6-3-1 Kashiwanoha, Kashiwa, Chiba 277-0882 (Japan); Hiramatsu, Muneyuki [Yamanashi Prefectural Police H.Q., 312-4 Kubonakajima, Isawa-cho, Usui, Yamanashi 406-0036 (Japan); Hino, Tomonori; Otake, Takuma [Metropolitan Police Department, 2-1-1 Kasumigaseki, Chiyoda-ku, Tokyo 100-8929 (Japan); Okamoto, Takashi; Miyamoto, Hiroki; Honma, Masakatsu; Watanabe, Norimichi [National Research Institute of Police Science, 6-3-1 Kashiwanoha, Kashiwa, Chiba 277-0882 (Japan)

    2015-04-28

    Highlights: • We chose 8-component hydrocarbon mixture as a model gasoline, and defined the molar mass of gasoline. • We proposed an evaporation model assuming a 2-component mixture of gasoline and ETBE. • We predicted the change in the vapor pressure of ETBE-blended gasoline by evaporation. • The vapor pressures were measured and compared as a means of verifying the model. • We presented the method for predicting flash points of the ETBE-blended gasoline. - Abstract: To reduce greenhouse gas emissions, which contribute to global warming, production of gasoline blended with ethyl tert-buthyl ether (ETBE) is increasing annually. The flash point of ETBE is higher than that of gasoline, and blending ETBE into gasoline will change the flash point and the vapor pressure. Therefore, it is expected that the fire hazard caused by ETBE-blended gasoline would differ from that caused by normal gasoline. The aim of this study was to acquire the knowledge required for estimating the fire hazard of ETBE-blended gasoline. Supposing that ETBE-blended gasoline was a two-component mixture of gasoline and ETBE, we developed a prediction model that describes the vapor pressure and flash point of ETBE-blended gasoline in an arbitrary ETBE blending ratio. We chose 8-component hydrocarbon mixture as a model gasoline, and defined the relation between molar mass of gasoline and mass loss fraction. We measured the changes in the vapor pressure and flash point of gasoline by blending ETBE and evaporation, and compared the predicted values with the measured values in order to verify the prediction model. The calculated values of vapor pressures and flash points corresponded well to the measured values. Thus, we confirmed that the change in the evaporation characteristics of ETBE-blended gasoline by evaporation could be predicted by the proposed model. Furthermore, the vapor pressure constants of ETBE-blended gasoline were obtained by the model, and then the distillation curves were

  4. Lysozyme plays a dual role against the dimorphic fungus Paracoccidioides brasiliensis A lisozima desempenha um papel duplo contra o fungo dimórfico Paracoccidioides brasiliensis

    Directory of Open Access Journals (Sweden)

    Damaris Lopera

    2008-06-01

    Full Text Available In order to determine the role of lysozyme, an antimicrobial peptide belonging to the innate immune system, against the dimorphic fungus Paracoccidioides brasiliensis, co-cultures of the MH-S murine alveolar macrophages cell line with P. brasiliensis conidia were done; assays to evaluate the effect of physiological and inflammatory concentrations of lysozyme directly on the fungus life cycle were also undertaken. We observed that TNF-α-activated macrophages significantly inhibited the conidia to yeast transition (p = 0.0043 and exerted an important fungicidal effect (p = 0.0044, killing 27% more fungal propagules in comparison with controls. Nonetheless, after adding a selective inhibitor of lysozyme, the fungicidal effect was reverted. When P. brasiliensis propagules were exposed directly to different concentrations of lysozyme, a dual effect was observed. Physiologic concentrations of the enzyme facilitated the conidia-to-yeast transition process (p Com a finalidade de determinar o papel da lisozima, um peptídeo antimicrobiano que pertence ao sistema imune inato, contra o fungo dimórfico Paracoccidioides brasiliensis, foram feitas co-culturas de uma linha de macrófagos alveolares murinos (MH-S com as conídias do fungo na presença ou não do TNF-α e/ou um inibidor da lisozima; também foram feitos ensaios que avaliaram o efeito das concentrações fisiológicas e inflamatórias de lisozima diretamente sobre o ciclo de vida do fungo. Observamos que os macrófagos ativados com a citoquina tiveram um efeito significativo na inibição da transição conídia/levedura (p = 0,0043 e exerceram um efeito fungicida importante (p = 0,0044, matando mais de 27% das propágulas do fungo em comparação com os macrófagos não ativados. No entanto, após ser o inibidor seletivo da lisozima adicionado, o efeito fungicida foi revertido. Quando os propágulos do fungo foram expostos diretamente a diferentes concentrações da lisozima, um duplo efeito

  5. THE COMBUSTION CHARACTERISTICS OF LIGNITE BLENDS

    Institute of Scientific and Technical Information of China (English)

    Cheng Jun; Zhou Junhu; Cao Xinyu; Cen Kefa

    2000-01-01

    The combustion characteristics of lignite blends were studied with a thermogravimetric analyzer (t.g.a.), at constant heating rate.The characteristic temperatures were determined from the burning profiles.It was found that the characteristic times of combustion reaction moved forward, the ignition temperature dropped and the burnout efficiency slightly changed when blending lignites.The characteristic parameters of blends could not be predicted as a linear function of the average values of the individual lignites.when blending with less reactive coal, the ignition and burnout characteristics of lignite turned worse.

  6. Size-dependent interaction of silica nanoparticles with lysozyme and bovine serum albumin proteins

    Science.gov (United States)

    Yadav, Indresh; Aswal, Vinod K.; Kohlbrecher, Joachim

    2016-05-01

    The interaction of three different sized (diameter 10, 18, and 28 nm) anionic silica nanoparticles with two model proteins—cationic lysozyme [molecular weight (MW) 14.7 kDa)] and anionic bovine serum albumin (BSA) (MW 66.4 kDa) has been studied by UV-vis spectroscopy, dynamic light scattering (DLS), and small-angle neutron scattering (SANS). The adsorption behavior of proteins on the nanoparticles, measured by UV-vis spectroscopy, is found to be very different for lysozyme and BSA. Lysozyme adsorbs strongly on the nanoparticles and shows exponential behavior as a function of lysozyme concentration irrespective of the nanoparticle size. The total amount of adsorbed lysozyme, as governed by the surface-to-volume ratio, increases on lowering the size of the nanoparticles for a fixed volume fraction of the nanoparticles. On the other hand, BSA does not show any adsorption for all the different sizes of the nanoparticles. Despite having different interactions, both proteins induce similar phase behavior where the nanoparticle-protein system transforms from one phase (clear) to two phase (turbid) as a function of protein concentration. The phase behavior is modified towards the lower concentrations for both proteins with increasing the nanoparticle size. DLS suggests that the phase behavior arises as a result of the nanoparticles' aggregation on the addition of proteins. The size-dependent modifications in the interaction potential, responsible for the phase behavior, have been determined by SANS data as modeled using the two-Yukawa potential accounting for the repulsive and attractive interactions in the systems. The protein-induced interaction between the nanoparticles is found to be short-range attraction for lysozyme and long-range attraction for BSA. The magnitude of attractive interaction irrespective of protein type is enhanced with increase in the size of the nanoparticles. The total (attractive+repulsive) potential leading to two-phase formation is found to be

  7. Blended education for systems architecting evaluation of the initial blended course version

    NARCIS (Netherlands)

    Muller, G.; Aker, J. van den; Postema, H.

    2016-01-01

    Blended education, the combination of traditional face-To-face education with online possibilities, is seen as the way for the future in education. Challenge for course providers is to learn how to offer blended education and to make the transition toward blended education. In this paper, we

  8. Blended education for systems architecting evaluation of the initial blended course version

    NARCIS (Netherlands)

    Muller, G.; Aker, J. van den; Postema, H.

    2016-01-01

    Blended education, the combination of traditional face-To-face education with online possibilities, is seen as the way for the future in education. Challenge for course providers is to learn how to offer blended education and to make the transition toward blended education. In this paper, we evaluat

  9. Pulsed electric field (PEF)-induced aggregation between lysozyme, ovalbumin and ovotransferrin in multi-protein system.

    Science.gov (United States)

    Wu, Li; Zhao, Wei; Yang, Ruijin; Yan, Wenxu

    2015-05-15

    The aggregation of multi-proteins is of great interest in food processing and a good understanding of the formation of aggregates during PEF processing is needed for the application of the process to pasteurize protein-based foods. The aggregates formation of a multi-protein system (containing ovalbumin, ovotransferrin and lysozyme) was studied through turbidity, size exclusion chromatography and SDS-PAGE patterns for interaction studies and binding forces. Results from size exclusion chromatography indicated that there was no soluble aggregates formed during PEF processing. The existence of lysozyme was important to form insoluble aggregates in the chosen ovalbumin solution. The results of SDS-PAGE patterns indicated that lysozyme was prone to precipitate, and was relatively the higher component of aggregates. Citric acid could be effective in inhibiting lysozyme from interacting with other proteins during PEF processing. Blocking the free sulphydryl by N-ethylmaleimide (NEM) did not affect aggregation inhibition.

  10. BINDING OF THERMO-SENSITIVE AND pH-SENSITIVE BUTYLATED POLY(ALLYLAMINE)S WITH LYSOZYME

    Institute of Scientific and Technical Information of China (English)

    Jing-jing Liu; Yun-feng Yan; Ping Yao

    2011-01-01

    Butyl modified poly(allylamine)s with butyl substitution degrees of 15% to 70% were prepared. The polymers show pH sensitive property and lower critical solution temperature (LCST) behavior. The LCST appears at lower temperature, lower pH and lower polymer concentration for the polymer with higher butylated degree. The binding of native lysozyme with the polymers depends on the hydrophobicity of the polymers at the pH range that the protein and the polymer carry the same positive charges. The increase of polymer hydrophobicity can increase the binding with lysozyme, but the self-aggregation of the polymer decreases the binding. The bound lysozyme molecules can recover their native activity completely after the dissociation of the complexes. Compared with native lysozyme, the denatured one which exposes the hydrophobic residues can increase the binding with the polymer and form stable complex nanoparticles.

  11. Evaluation of lysozyme, complement C3, and total protein in different developmental stages of Caspian kutum (Rutilus frisii kutum K.

    Directory of Open Access Journals (Sweden)

    Abdollahi Razieh

    2016-03-01

    Full Text Available In this study, non–specific immune parameters in fertilized eggs, eyed embryos, larvae 10, 25, 50, 60, and 70 days post hatch (DPH, and female broodstock of Caspian kutum, Rutilus frisii kutum (Kamensky, were evaluated. The lysozyme activity, complement C3, and total protein levels were measured with the turbidimetric, immunoturbidimetric, and Bradford methods, respectively. The results showed that lysozyme levels decreased from levels noted in the fertilized eggs until the larvae were 10 days old. Subsequently, significant increases in lysozyme levels were observed until 70 DPH. An increasing trend of complement component C3 was noted from the levels in fertilized eggs to 10 DPH, following which it decreased significantly. Total protein levels differed significantly in early developmental stages of Caspian kutum. The higher values of complement component C3 than of lysozyme in the early life stages could be indicative of the former’s more fundamental role.

  12. Ultra-sensitive quantification of lysozyme based on element chelate labeling and capillary electrophoresis–inductively coupled plasma mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Yang, MingWei [Key Laboratory of Analysis and Detection for Food Safety of Ministry of Education, Fujian Provincial Key Lab of Analysis and Detection for Food Safety, Department of Chemistry, Fuzhou University, Fuzhou 350108, Fujian (China); Department of Chemistry, Florida International University, Miami, FL 33199 (United States); Wu, WeiHua; Ruan, YaJuan; Huang, LiMei [Key Laboratory of Analysis and Detection for Food Safety of Ministry of Education, Fujian Provincial Key Lab of Analysis and Detection for Food Safety, Department of Chemistry, Fuzhou University, Fuzhou 350108, Fujian (China); Wu, Zujian [Department of Plant Protection, Fujian Agriculture and Forest University, Fuzhou 350002, Fujian (China); Cai, Yong [Department of Chemistry, Florida International University, Miami, FL 33199 (United States); Fu, FengFu, E-mail: fengfu@fzu.edu.cn [Key Laboratory of Analysis and Detection for Food Safety of Ministry of Education, Fujian Provincial Key Lab of Analysis and Detection for Food Safety, Department of Chemistry, Fuzhou University, Fuzhou 350108, Fujian (China); Department of Plant Protection, Fujian Agriculture and Forest University, Fuzhou 350002, Fujian (China)

    2014-02-17

    Graphical abstract: An ultra-sensitive method for the determination of lysozyme was developed based on the Gd{sup 3+} chelate labeling and CE–ICP–MS. The proposed method has an extremely low detection limit of 3.89 attomole and has been successfully used to detect lysozyme in saliva sample, showing excellent reliability. The success of the present method provides a new possibility for biological assays and clinical diagnoses. -- Highlights: •An ultra-sensitive method for detecting lysozyme based on CE–ICP–MS was described. •The proposed method has an extremely low detection limit of 3.89 attomole. •It can be used to detect trace lysozyme in saliva sample with a satisfied recovery. •The method provides a new potential for sensitive detection of low-abundant proteins. -- Abstract: In this study, an ultra-sensitive method for the quantification of lysozyme based on the Gd{sup 3+} diethylenetriamine-N,N,N′,N″,N″-pentaacetic acid labeling and capillary electrophoresis–inductively coupled plasma mass spectrometry (CE–ICP–MS) was described. The Gd{sup 3+}-tagged lysozyme was effectively separated by capillary electrophoresis (CE) and sensitively determined by inductively coupled plasma mass spectrometry (ICP–MS). Based on the gadolinium-tagging and CE–ICP–MS, the lysozyme was determined within 12 min with an extremely low detection limit of 3.89 attomole (3.89 × 10{sup −11} mol L{sup −1} for 100 nL of sample injection) and a RSD < 6% (n = 5). The proposed method has been successfully used to detect lysozyme in saliva samples with a recovery of 91–106%, suggesting that our method is sensitive and reliable. The success of the present method provides a new potential for the biological assays and sensitive detection of low-abundant proteins.

  13. A novel analytical procedure for assaying lysozyme activity using an end-blocked chitotetraose derivative as substrate.

    Science.gov (United States)

    Ogata, Makoto; Matsui, Megumi; Kono, Haruka; Matsuzaki, Yuka; Kato, Yuna; Usui, Taichi

    2017-09-23

    An end-modified β-d-galactosyl chitotetraose derivative [4(4)-O-β-d-galactosyl-β-tri-N-acetylchitotriosyl 2-acetamide-2,3-dideoxy-glucopyranose; Gal(GlcN)3D] was designed and synthesized from chitin tetrasaccharide. The derivative was chemically modified by dehydration of the reducing end GlcN and enzymatic addition of a Gal group to the non-reducing end GlcN. Hydrolysis of Gal(GlcN)3D and related compounds using hen egg-white lysozyme was then examined. Gal(GlcN)3D was specifically cleaved to Gal(GlcN)2 and GlcND. Kinetic studies and docking simulations were further conducted to elucidate its mode of binding to lysozyme. These analyses revealed the binding of Gal(GlcN)3D to lysozyme is more favorable than that of (GlcN)4D. We conclude the 4-O-substituted Gal group at the non-reducing end of Gal(GlcN)3D does not prohibit the action of lysozyme, but gives some affinity to the subsite (i.e. equivalent to GlcN). From these results, a new assay method for quantifying lysozyme was established by utilizing the Morgan-Elson reaction based on the generation of product D (2-acetamide-2,3-dideoxy-glucopyranose), which serves as a chromophore, formed from Gal(GlcN)3D by lysozyme through a conjugated reaction involving β-N-acetylhexosaminidase. The assay system gave a linear dose-response curve in the range of 2-31 μg of lysozyme during a 15 min incubation. This novel assay method for the quantification of lysozyme is highly specific, sensitive, accurate and reproducible. Copyright © 2017 Elsevier Inc. All rights reserved.

  14. Status, Antimicrobial Mechanism, and Regulation of Natural Preservatives in Livestock Food Systems

    Science.gov (United States)

    Lee, Na-Kyoung; Paik, Hyun-Dong

    2016-01-01

    This review discusses the status, antimicrobial mechanisms, application, and regulation of natural preservatives in livestock food systems. Conventional preservatives are synthetic chemical substances including nitrates/nitrites, sulfites, sodium benzoate, propyl gallate, and potassium sorbate. The use of artificial preservatives is being reconsidered because of concerns relating to headache, allergies, and cancer. As the demand for biopreservation in food systems has increased, new natural antimicrobial compounds of various origins are being developed, including plant-derived products (polyphenolics, essential oils, plant antimicrobial peptides (pAMPs)), animal-derived products (lysozymes, lactoperoxidase, lactoferrin, ovotransferrin, antimicrobial peptide (AMP), chitosan and others), and microbial metabolites (nisin, natamycin, pullulan, ε-polylysine, organic acid, and others). These natural preservatives act by inhibiting microbial cell walls/membranes, DNA/RNA replication and transcription, protein synthesis, and metabolism. Natural preservatives have been recognized for their safety; however, these substances can influence color, smell, and toxicity in large amounts while being effective as a food preservative. Therefore, to evaluate the safety and toxicity of natural preservatives, various trials including combinations of other substances or different food preservation systems, and capsulation have been performed. Natamycin and nisin are currently the only natural preservatives being regulated, and other natural preservatives will have to be legally regulated before their widespread use. PMID:27621697

  15. Status, Antimicrobial Mechanism, and Regulation of Natural Preservatives in Livestock Food Systems.

    Science.gov (United States)

    Lee, Na-Kyoung; Paik, Hyun-Dong

    2016-01-01

    This review discusses the status, antimicrobial mechanisms, application, and regulation of natural preservatives in livestock food systems. Conventional preservatives are synthetic chemical substances including nitrates/nitrites, sulfites, sodium benzoate, propyl gallate, and potassium sorbate. The use of artificial preservatives is being reconsidered because of concerns relating to headache, allergies, and cancer. As the demand for biopreservation in food systems has increased, new natural antimicrobial compounds of various origins are being developed, including plant-derived products (polyphenolics, essential oils, plant antimicrobial peptides (pAMPs)), animal-derived products (lysozymes, lactoperoxidase, lactoferrin, ovotransferrin, antimicrobial peptide (AMP), chitosan and others), and microbial metabolites (nisin, natamycin, pullulan, ε-polylysine, organic acid, and others). These natural preservatives act by inhibiting microbial cell walls/membranes, DNA/RNA replication and transcription, protein synthesis, and metabolism. Natural preservatives have been recognized for their safety; however, these substances can influence color, smell, and toxicity in large amounts while being effective as a food preservative. Therefore, to evaluate the safety and toxicity of natural preservatives, various trials including combinations of other substances or different food preservation systems, and capsulation have been performed. Natamycin and nisin are currently the only natural preservatives being regulated, and other natural preservatives will have to be legally regulated before their widespread use.

  16. Antimicrobial Resistant Streptococcus pneumoniae

    Directory of Open Access Journals (Sweden)

    B Khanal

    2010-09-01

    Full Text Available Introduction: Pneumococcal infections are important cause of morbidity and mortality. Knowledge of antimicrobial susceptibility patterns plays important role in the selection of appropriate therapy. Present study was undertaken to analyze the susceptibility patterns of pneumococcal isolates against commonly used antimicrobials with special reference to determination of minimum inhibitory concentration (MIC of penicillin in a tertiary care hospital in eastern Nepal. Methods: Twenty-six strains of S. pneumoniae isolated from various clinical specimens submitted to microbiology laboratory were evaluated. All isolates were tested for antimicrobial susceptibility by disk diffusion method. MIC of penicillin was tested by broth dilution method. Results: Of the total isolates 19 (73% were from invasive infections. Seven isolates were resistant to cotrimoxazole. No resistance to penicillin was seen in disk diffusion testing. Less susceptibility to penicillin (MIC 0.1-1.0 mg/L was observed in five (17% isolates. High level resistance to penicillin was not detected. One isolate was multidrug resistant. Conclusions: S. pneumoniaeisolates with intermediate resistance to penicillin prevail in Tertiary Care Hospital in eastern Nepal, causing invasive and noninvasive infections. As intermediate resistance is not detected in routine susceptibility testing, determination of MIC is important. It helps not only in the effective management of life threatening infections but is also essential in continuous monitoring and early detection of resistance. In addition, further study on pneumococcal infections, its antimicrobial resistance profile and correlation with clinical and epidemiological features including serotypes and group prevalence is recommended in future. Keywords: antimicrobial susceptibility pattern, penicillin, Streptococcus pneumoniae.

  17. Antimicrobials, stress and mutagenesis.

    Directory of Open Access Journals (Sweden)

    Alexandro Rodríguez-Rojas

    2014-10-01

    Full Text Available Cationic antimicrobial peptides are ancient and ubiquitous immune effectors that multicellular organisms use to kill and police microbes whereas antibiotics are mostly employed by microorganisms. As antimicrobial peptides (AMPs mostly target the cell wall, a microbial 'Achilles heel', it has been proposed that bacterial resistance evolution is very unlikely and hence AMPs are ancient 'weapons' of multicellular organisms. Here we provide a new hypothesis to explain the widespread distribution of AMPs amongst multicellular organism. Studying five antimicrobial peptides from vertebrates and insects, we show, using a classic Luria-Delbrück fluctuation assay, that cationic antimicrobial peptides (AMPs do not increase bacterial mutation rates. Moreover, using rtPCR and disc diffusion assays we find that AMPs do not elicit SOS or rpoS bacterial stress pathways. This is in contrast to the main classes of antibiotics that elevate mutagenesis via eliciting the SOS and rpoS pathways. The notion of the 'Achilles heel' has been challenged by experimental selection for AMP-resistance, but our findings offer a new perspective on the evolutionary success of AMPs. Employing AMPs seems advantageous for multicellular organisms, as it does not fuel the adaptation of bacteria to their immune defenses. This has important consequences for our understanding of host-microbe interactions, the evolution of innate immune defenses, and also sheds new light on antimicrobial resistance evolution and the use of AMPs as drugs.

  18. Effect of surface energy of solid surfaces on the micro- and macroscopic properties of adsorbed BSA and lysozyme.

    Science.gov (United States)

    Sharma, Indu; Pattanayek, Sudip K

    2017-07-01

    The surface energy, a macroscopic property, depends on the chemical functionality and micro- and macroscopic roughness of the surface. The adsorption of two widely used proteins bovine serum albumin (BSA) and lysozyme on surfaces of four different chemical functionalities were done to find out the interrelation between macroscopic and microscopic properties. We have observed the secondary structure of protein after its adsorption. In addition, we observed the variation of surface energy of proteins due to variation in adsorption time, change in protein concentration and effect of a mixture of proteins. Surfaces of three different chemical functionalities namely, amine, hydroxyl and octyl were obtained through self-assembled monolayer on silica surfaces and were tested for responses towards adsorption of lysozyme and BSA. The adsorbed lysozyme has higher surface energy than the adsorbed BSA on amine and octyl surfaces. On hydroxyl functional surface, the surface energy due to the adsorbed lysozyme or BSA increases slowly with time. The surface energy of the adsorbed protein increases gradually with increasing protein concentration on hydrophobic surfaces. On hydrophilic surfaces, with increasing BSA concentration in bulk solution, the surface energy of the adsorbed protein on GPTMS and amine surfaces is maximum at 1μM concentration. During the adsorption from a mixture of BSA and lysozyme on octyl surface, first lysozyme adsorbs and subsequent BSA adsorption leads to a high surface energy. Copyright © 2016. Published by Elsevier B.V.

  19. Studies on the Refolding of Egg White Lysozyme Denatured by Urea Using "Phase Diagram" Method of Fluorescence

    Institute of Scientific and Technical Information of China (English)

    BIAN Liu-Jiao; DONG Fa-Xin; LIANG Chang-Li; YANG Xiao-Yan; LIU Li

    2007-01-01

    The refolding of reduced and non-reducing egg white lysozymes in a urea solution was studied by a "phase diagram" method of fluorescence.The result showed that in the refolding of the reduced egg white lysozyme,an intermediate state of an egg white lysozyme exists at the urea concentrations in a final renaturation solution being about 4.5 mol/L,their refolding follows a three-state model; while in the refolding of the non-reducing egg white iysozyme,two intermediate states exist at the urea concentrations being separately 4.0 and 2.5 mol/L,and their refolding follows a four-state model.Through the comparison between the unfolding and refolding of an egg white lysozyme in the urea solution,it was found that both of the refolding of reduced and non-reducing egg white lysozyme molecules was irreversible to their unfolding in the urea solution.Finally,a suggested refolding was separately presented for the reduced and non-reducing egg white lysozymes in the urea solution.

  20. A comparative study on the aggregating effects of guanidine thiocyanate, guanidine hydrochloride and urea on lysozyme aggregation

    Energy Technology Data Exchange (ETDEWEB)

    Emadi, Saeed, E-mail: emadi@iasbs.ac.ir; Behzadi, Maliheh

    2014-08-08

    Highlights: • Lysozyme aggregated in guanidine thiocyanate (1.0 and 2.0 M). • Lysozyme aggregated in guanidine hydrochloride (4 and 5 M). • Lysozyme did not aggregated at any concentration (0.5–5 M) of urea. • Unfolding pathway is more important than unfolding per se in aggregation. - Abstract: Protein aggregation and its subsequent deposition in different tissues culminate in a diverse range of diseases collectively known as amyloidoses. Aggregation of hen or human lysozyme depends on certain conditions, namely acidic pH or the presence of additives. In the present study, the effects on the aggregation of hen egg-white lysozyme via incubation in concentrated solutions of three different chaotropic agents namely guanidine thiocyanate, guanidine hydrochloride and urea were investigated. Here we used three different methods for the detection of the aggregates, thioflavin T fluorescence, circular dichroism spectroscopy and atomic force microscopy. Our results showed that upon incubation with different concentrations (0.5, 1.0, 2.0, 3.0, 4.0, 5.0 M) of the chemical denaturants, lysozyme was aggregated at low concentrations of guanidine thiocyanate (1.0 and 2.0 M) and at high concentrations of guanidine hydrochloride (4 and 5 M), although no fibril formation was detected. In the case of urea, no aggregation was observed at any concentration.

  1. Effect of ethanol as a co-solvent on the aerosol performance and stability of spray-dried lysozyme

    DEFF Research Database (Denmark)

    Ji, Shuying; Thulstrup, Peter Waaben; Mu, Huiling

    2016-01-01

    In the spray drying process, organic solvents can be added to facilitate drying, accommodate certain functional excipients, and modify the final particle characteristics. In this study, lysozyme was used as a model pharmaceutical protein to study the effect of ethanol as a co-solvent on the stabi......In the spray drying process, organic solvents can be added to facilitate drying, accommodate certain functional excipients, and modify the final particle characteristics. In this study, lysozyme was used as a model pharmaceutical protein to study the effect of ethanol as a co......-solvent on the stability and aerosol performance of spray-dried protein. Lysozyme was dissolved in solutions with various ratios of ethanol and water, and subsequently spray-dried. A change from spherical particles into wrinkled and folded particles was observed upon increasing the ratio of ethanol in the feed....... The aerosol performance of the spray-dried lysozyme from ethanol-water solution was improved compared to that from pure water. The conformation of lysozyme in the ethanol-water solution and spray dried powder was altered, but the native structure of lysozyme was restored upon reconstitution in water after...

  2. Pulsed laser deposition of the lysozyme protein: an unexpected “Inverse MAPLE” process

    DEFF Research Database (Denmark)

    Schou, Jørgen; Matei, Andreea; Constantinescu, Catalin

    2012-01-01

    the ejection and deposition of lysozyme. This can be called an “inverse MAPLE” process, since the ratio of “matrix” to film material in the target is 10:90, which is inverse of the typical MAPLE process where the film material is dissolved in the matrix down to several wt.%. Lysozyme is a well-known protein...... which is used in food processing and is also an important constituent of human secretions such as sweat and saliva. It has a well-defined mass (14307 u) and can easily be detected by mass spectrometric methods such as MALDI (Matrix-assisted laser desorption ionization) in contrast to many other organic...

  3. Study of lysozyme mobility and binding free energy during adsorption on a graphene surface

    Energy Technology Data Exchange (ETDEWEB)

    Nakano, C. Masato [Flintridge Preparatory School, La Canada Flintridge, California 91011 (United States); Ma, Heng; Wei, Tao, E-mail: twei@lamar.edu [Dan F. Smith Department of Chemical Engineering, Lamar University, Beaumont, Texas 77710 (United States)

    2015-04-13

    Understanding protein adsorption is a key to the development of biosensors and anti-biofouling materials. Hydration essentially controls the adsorption process on hydrophobic surfaces, but its effect is complicated by various factors. Here, we present an ideal model system to isolate hydration effects—lysozyme adsorption on a flat hydrophobic graphene surface. Our all-atom molecular dynamics and molecular-mechanics/Poisson-Boltzmann surface area computation study reveal that lysozyme on graphene displays much larger diffusivity than in bulk water. Protein's hydration free energy within the first hydration shell is dominated by the protein-water electrostatic interactions and acts as an energy barrier for protein adsorption. On the other hand, the surface tension, especially that from the hydrophobic graphene, can effectively weaken the barrier to promote adsorption.

  4. Lysozyme refolding at high concentration by dilution and size-exclusion chromatography

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    This study of renaturation by dilution and size exclusion chromatography (SEC) addition of urea to improve yield as well as the initial and final protein concentrations showed that although urea decreased the rate of lysozyme refolding, it could suppress protein aggregation to sustain the pathway of correct refolding at high protein concentration; and that there existed an optimum urea concentration in renaturation buffer. Under the above conditions, lysozyme was successfully refolded from initial concentration of up to 40 mg/mL by dilution and 100 mg/mL by SEC, with the yield of the former being more than 40% and that of the latter being 34.8%. Especially, under the condition of 30 min interval time, i.e. τ>2(tR2-tR1), the efficiency was increased by 25% and the renaturation buffer could be recycled for SEC refolding in continuous operation of downstream process.

  5. Laser ablation of the lysozyme protein: a model system for soft materials

    DEFF Research Database (Denmark)

    Schou, Jørgen; Matei, Andreea; Constantinescu, Catalin

    ionization) in contrast to many other organic materials. Also the thermal properties, including the heat-induced decomposition behavior are comparatively well-known. For laser-irradiation at wavelengths above 310 nm, no photochemical processes occur initially, but the material is ejected via photothermal......Lysozyme is a well-known protein which is used in food processing and is also an important constituent of human secretions such as sweat and saliva. It has a well-defined mass (14307 u) and can easily be detected by mass spectrometric methods such as MALDI (Matrix-assisted laser desorption...... on the results of molecular-level modeling. In particular, the effect of the possible presence of trapped water pockets in the lysozyme targets is investigated in the simulations and the minimum amount of water required for the lift off of the intact molecules is established....

  6. Using THz Spectroscopy, Evolutionary Network Analysis Methods, and MD Simulation to Map the Evolution of Allosteric Communication Pathways in c-Type Lysozymes.

    Science.gov (United States)

    Woods, Kristina N; Pfeffer, Juergen

    2016-01-01

    It is now widely accepted that protein function is intimately tied with the navigation of energy landscapes. In this framework, a protein sequence is not described by a distinct structure but rather by an ensemble of conformations. And it is through this ensemble that evolution is able to modify a protein's function by altering its landscape. Hence, the evolution of protein functions involves selective pressures that adjust the sampling of the conformational states. In this work, we focus on elucidating the evolutionary pathway that shaped the function of individual proteins that make-up the mammalian c-type lysozyme subfamily. Using both experimental and computational methods, we map out specific intermolecular interactions that direct the sampling of conformational states and accordingly, also underlie shifts in the landscape that are directly connected with the formation of novel protein functions. By contrasting three representative proteins in the family we identify molecular mechanisms that are associated with the selectivity of enhanced antimicrobial properties and consequently, divergent protein function. Namely, we link the extent of localized fluctuations involving the loop separating helices A and B with shifts in the equilibrium of the ensemble of conformational states that mediate interdomain coupling and concurrently moderate substrate binding affinity. This work reveals unique insights into the molecular level mechanisms that promote the progression of interactions that connect the immune response to infection with the nutritional properties of lactation, while also providing a deeper understanding about how evolving energy landscapes may define present-day protein function.

  7. Antimicrobial stewardship: Limits for implementation

    NARCIS (Netherlands)

    Sinha, Bhanu

    2014-01-01

    Antibiotic stewardship programme (ASP) is a multifaceted approach to improve patients' clinical outcomes, prevent the emergence of antimicrobial resistance, and reduce hospital costs by prudent and focused antimicrobial use. Development of local treatment guidelines according to local ecology, rapid

  8. General principles of antimicrobial therapy.

    Science.gov (United States)

    Leekha, Surbhi; Terrell, Christine L; Edson, Randall S

    2011-02-01

    Antimicrobial agents are some of the most widely, and often injudiciously, used therapeutic drugs worldwide. Important considerations when prescribing antimicrobial therapy include obtaining an accurate diagnosis of infection; understanding the difference between empiric and definitive therapy; identifying opportunities to switch to narrow-spectrum, cost-effective oral agents for the shortest duration necessary; understanding drug characteristics that are peculiar to antimicrobial agents (such as pharmacodynamics and efficacy at the site of infection); accounting for host characteristics that influence antimicrobial activity; and in turn, recognizing the adverse effects of antimicrobial agents on the host. It is also important to understand the importance of antimicrobial stewardship, to know when to consult infectious disease specialists for guidance, and to be able to identify situations when antimicrobial therapy is not needed. By following these general principles, all practicing physicians should be able to use antimicrobial agents in a responsible manner that benefits both the individual patient and the community.

  9. Cloning and molecular characterization of two invertebrate-type lysozymes from Anopheles gambiae

    OpenAIRE

    Paskewitz, S. M.; Li, B.; Kajla, M. K.

    2008-01-01

    We sequenced and characterized two novel invertebrate-type lysozymes from the mosquito Anopheles gambiae. Alignment and phylogenetic analysis of these and a number of related insect proteins identified through bioinformatics strategies showed a high degree of conservation of this protein family throughout the Class Insecta. Expression profiles were examined for the two mosquito genes through semiquantitative and real-time PCR analysis. Lys i-1 transcripts were found in adult females in the fa...

  10. [Molecular cloning, recombinant expression and characterization of lysozyme from Chinese shrimp Fenneropenaeus chinensis].

    Science.gov (United States)

    Bu, Xingjiang; Du, Xinjun; Zhou, Wenjie; Zhao, Xiaofan; Wang, Jinxing

    2008-05-01

    Lysozyme hydrolyses bacterial cell walls and acts as a nonspecific innate immunity molecule against the invasion of bacterial pathogens. We cloned the cDNA of lysozyme from Fenneropenaeus chinensis and named Fc-lysozyme (FcLyz in short). The full length of the gene was of 709 bp, and the open reading frame (477 bp) encoded 158 amino acids. The predicted protein had a signal peptide (-1--18 residue) and molecular weight of the mature protein (residue 1-140) was of 16.2 kD. A Lyz 1 domain (residue 1-130) in the lysozyme was found by SMART analysis. The results of semiquantity RT-PCR showed that FcLyz was constitutively expressed in tested tissues in a low level in normal shrimp, and up-regulated in hemocytes, heart, hepatopancreas and gill of bacterial challenged shrimp. The DNA fragment of mature Fc-Lys was subcloned to pET-30a (+) expression vector, the recombinant plasmid was transformed into Escherichia coli BL21 (DE3) and then induced by isopropylthio-beta-D-galactoside (IPTG). The antibacterial activity of the purified recombinant FcLys was analyzed and minimal inhibitory concentration (MIC) was assayed. The recombinant protein showed high antibacterial activity against some Gram-positive bacteria, and MIC reached 3.43 micromol/L, and relatively low activity against Gram-negative bacteria. All together, the Fc-Lys was regulated by pathogen infection and had antibacterial activity. This suggested that the FcLyz may be one of the important molecules against pathogens in innate immunity of the shrimp.

  11. Evaluating the fitness of human lysozyme transgenic dairy goats: growth and reproductive traits

    OpenAIRE

    2010-01-01

    While there are many reports in the literature describing the attributes of specific applications of transgenic animals for agriculture, there are relatively few studies focusing on the fitness of the transgenic animals themselves. This work was designed to gather information on genetically modified food animals to determine if the presence of a transgene can impact general animal production traits. More specifically, we used a line of transgenic dairy goats expressing human lysozyme in their...

  12. Phase equilibria for salt-induced lysozyme precipitation: Effect of salt concentration and pH

    OpenAIRE

    Popova, E.; WATANABE, E. O.; PESSOA FILHO, P. A.; Maurer, G.

    2008-01-01

    The salt-induced precipitation of lysozyme from aqueous solutions was studied at 25 degrees C and various pH values by cloud-point investigations, precipitation experiments (analysing the compositions of the coexisting phases) and microscopic investigations of the precipitates. Sodium sulphate as well as ammonium sulphate were used to induce the precipitation. The experimental results are discussed and used to develop a scheme of the phase equilibrium in water-rich aqueous solutions of lysozy...

  13. Effect of Cholesterol on the Properties of Spray-Dried Lysozyme-Loaded Liposomal Powders

    OpenAIRE

    Charnvanich, Dusadee; Vardhanabhuti, Nontima; Kulvanich, Poj

    2010-01-01

    The influence of cholesterol (Chol) in the liposomal bilayer on the properties of inhalable protein-loaded liposomal powders prepared by spray-drying technique was investigated. Lysozyme (LSZ) was used as a model protein. Feed solution for spray drying was prepared by direct mixing of aqueous solution of LSZ with mannitol solution and empty liposome dispersions composed of hydrogenated phosphatidylcholine and Chol at various molar ratios. The spray-dried powders were characterized with respec...

  14. Structural relationships in the lysozyme superfamily: significant evidence for glycoside hydrolase signature motifs.

    Directory of Open Access Journals (Sweden)

    Alexandre Wohlkönig

    Full Text Available BACKGROUND: Chitin is a polysaccharide that forms the hard, outer shell of arthropods and the cell walls of fungi and some algae. Peptidoglycan is a polymer of sugars and amino acids constituting the cell walls of most bacteria. Enzymes that are able to hydrolyze these cell membrane polymers generally play important roles for protecting plants and animals against infection with insects and pathogens. A particular group of such glycoside hydrolase enzymes share some common features in their three-dimensional structure and in their molecular mechanism, forming the lysozyme superfamily. RESULTS: Besides having a similar fold, all known catalytic domains of glycoside hydrolase proteins of lysozyme superfamily (families and subfamilies GH19, GH22, GH23, GH24 and GH46 share in common two structural elements: the central helix of the all-α domain, which invariably contains the catalytic glutamate residue acting as general-acid catalyst, and a β-hairpin pointed towards the substrate binding cleft. The invariant β-hairpin structure is interestingly found to display the highest amino acid conservation in aligned sequences of a given family, thereby allowing to define signature motifs for each GH family. Most of such signature motifs are found to have promising performances for searching sequence databases. Our structural analysis further indicates that the GH motifs participate in enzymatic catalysis essentially by containing the catalytic water positioning residue of inverting mechanism. CONCLUSIONS: The seven families and subfamilies of the lysozyme superfamily all have in common a β-hairpin structure which displays a family-specific sequence motif. These GH β-hairpin motifs contain potentially important residues for the catalytic activity, thereby suggesting the participation of the GH motif to catalysis and also revealing a common catalytic scheme utilized by enzymes of the lysozyme superfamily.

  15. Concentration dependent switch in the kinetic pathway of lysozyme fibrillation: Spectroscopic and microscopic analysis

    Science.gov (United States)

    Kiran Kumar, E.; Prasad, Deepak Kumar; Prakash Prabhu, N.

    2017-08-01

    Formation of amyloid fibrils is found to be a general tendency of many proteins. Investigating the kinetic mechanisms and structural features of the intermediates and the final fibrillar state is essential to understand their role in amyloid diseases. Lysozyme, a notable model protein for amyloidogenic studies, readily formed fibrils in vitro at neutral pH in the presence of urea. It, however, showed two different kinetic pathways under varying urea concentrations when probed with thioflavin T (ThT) fluorescence. In 2 M urea, lysozyme followed a nucleation-dependent fibril formation pathway which was not altered by varying the protein concentration from 2 mg/ml to 8 mg/ml. In 4 M urea, the protein exhibited concentration dependent change in the mechanism. At lower protein concentrations, lysozyme formed fibrils without any detectable nuclei (nucleation-independent polymerization pathway). When the concentration of the protein was increased above 3 mg/ml, the protein followed nucleation-dependent polymerization pathway as observed in the case of 2 M urea condition. This was further verified using microscopic images of the fibrils. The kinetic parameters such as lag time, elongation rate, and fibrillation half-time, which were derived from ThT fluorescence changes, showed linear dependency against the initial protein concentration suggested that under the nucleation-dependent pathway conditions, the protein followed primary-nucleation mechanism without any significant secondary nucleation events. The results also suggested that the differences in the initial protein conformation might alter the mechanism of fibrillation; however, at the higher protein concentrations lysozyme shifted to nucleation-dependent pathway.

  16. Antimicrobial Peptides (AMPs

    Directory of Open Access Journals (Sweden)

    Mehrzad Sadredinamin

    2016-04-01

    Full Text Available Antimicrobial peptides (AMPs are extensive group of molecules that produced by variety tissues of invertebrate, plants, and animal species which play an important role in their immunity response. AMPs have different classifications such as; biosynthetic machines, biological sources, biological functions, molecular properties, covalent bonding patterns, three dimensional structures, and molecular targets.These molecules have multidimensional properties including antimicrobial activity, antiviral activity, antifungal activity, anti-parasite activity, biofilm control, antitumor activity, mitogens activity and linking innate to adaptive immunity that making them promising agents for therapeutic drugs. In spite of this advantage of AMPs, their clinical developments have some limitation for commercial development. But some of AMPs are under clinical trials for the therapeutic purpose such as diabetic foot ulcers, different bacterial infections and tissue damage. In this review, we emphasized on the source, structure, multidimensional properties, limitation and therapeutic applications of various antimicrobial peptides.

  17. Strong antimicrobial coatings: single-walled carbon nanotubes armored with biopolymers.

    Science.gov (United States)

    Nepal, Dhriti; Balasubramanian, Shankar; Simonian, Aleksandr L; Davis, Virginia A

    2008-07-01

    Large scale biomimetic single-walled carbon nanotube (SWNT) coatings with significant antimicrobial activity, high Young's Modulus, and controlled morphology were fabricated using layer-by-layer assembly. Thickness was controlled within 1.6 nm and SWNT orientation was controlled using a directed air stream. This unique blend of multifunctionality and vertical and lateral control of a bottom-up assembly process is a significant advancement in developing macroscale assemblies with the combined attributes of SWNTs and natural materials.

  18. Structuring of Interface-Modified Polymer Blends

    DEFF Research Database (Denmark)

    Lyngaae-Jørgensen, Jørgen

    1999-01-01

    The paper treats the case where blends of polystyrene (PS), poly (dimethylsiloxane) (PDMS) and a diblock copolymer of PS and PDMS are used as model materials. This modelsystem is predicted to be "stable" in discrete blends in simple shear flow. Stable in the sence that the block copolymer can not...

  19. A Review on Conceptual Blending Theory

    Institute of Scientific and Technical Information of China (English)

    刘丽

    2010-01-01

    The CBT(Conceptual Blending Theory)is rapidly emerging as a major force in cognitive science and provides a unifying umbrella framework for a range of cognitive phenomena.The present paper is to have a general review of the conceptual blending theory through illustrating its four-space theory in order to have a better comprehension of its nature.

  20. Storage studies on mustard oil blends.

    Science.gov (United States)

    Chugh, Bhawna; Dhawan, Kamal

    2014-04-01

    Mustard oil blends were investigated for fatty acid composition and oxidative stability during storage for 3 months at room temperature (15 °C to 35 °C). The blends were prepared using raw mustard oil with selected refined vegetable oils namely; palm, safflower, soybean, rice bran, sunflower and sesame oil (raw). The fatty acid compositions of all these blends were studied using GLC. The developed blends were found to obey the ideal fatty acid ratio as laid down by health agencies i.e. 1:2:1:: SFA:MUFA:PUFA. The oxidative stability of blends was studied by measuring peroxide value (PV), Kries and Thiobarbituric acid (TBA) test. Blends MPSu (mustard oil, palm oil and sunflower oil), MPT (mustard oil, palm oil and sesame oil) and MPGr (mustard oil, palm oil and groundnut oil) were more stable than other blends during storage. The presence of mustard oil in all blends might make them a healthier option for many consumers as it is a rich source of ω-3 fatty acids and has anti-carcinogenic properties.

  1. Enhancing Students' Language Skills through Blended Learning

    Science.gov (United States)

    Banditvilai, Choosri

    2016-01-01

    This paper presents a case study of using blended learning to enhance students' language skills and learner autonomy in an Asian university environment. Blended learning represents an educational environment for much of the world where computers and the Internet are readily available. It combines self-study with valuable face-to-face interaction…

  2. Preparing Teachers for Emerging Blended Learning Environments

    Science.gov (United States)

    Oliver, Kevin M.; Stallings, Dallas T.

    2014-01-01

    Blended learning environments that merge learning strategies, resources, and modes have been implemented in higher education settings for nearly two decades, and research has identified many positive effects. More recently, K-12 traditional and charter schools have begun to experiment with blended learning, but to date, research on the effects of…

  3. Improving Curriculum through Blended Learning Pedagogy

    Science.gov (United States)

    Darojat, Ojat

    2016-01-01

    This paper is a study of blended learning pedagogy in open and distance learning (ODL), involving two universities in Southeast Asia, STOU Thailand and UT Indonesia. The purpose of this study is to understand the issues related to the implementation of blended-learning pedagogy. Qualitative case study was employed to optimize my understanding of…

  4. Blended Learning in Personalized Assistive Learning Environments

    Science.gov (United States)

    Marinagi, Catherine; Skourlas, Christos

    2013-01-01

    In this paper, the special needs/requirements of disabled students and cost-benefits for applying blended learning in Personalized Educational Learning Environments (PELE) in Higher Education are studied. The authors describe how blended learning can form an attractive and helpful framework for assisting Deaf and Hard-of-Hearing (D-HH) students to…

  5. PAIRWISE BLENDING OF HIGH LEVEL WASTE (HLW)

    Energy Technology Data Exchange (ETDEWEB)

    CERTA, P.J.

    2006-02-22

    The primary objective of this study is to demonstrate a mission scenario that uses pairwise and incidental blending of high level waste (HLW) to reduce the total mass of HLW glass. Secondary objectives include understanding how recent refinements to the tank waste inventory and solubility assumptions affect the mass of HLW glass and how logistical constraints may affect the efficacy of HLW blending.

  6. Preparing Teachers for Emerging Blended Learning Environments

    Science.gov (United States)

    Oliver, Kevin M.; Stallings, Dallas T.

    2014-01-01

    Blended learning environments that merge learning strategies, resources, and modes have been implemented in higher education settings for nearly two decades, and research has identified many positive effects. More recently, K-12 traditional and charter schools have begun to experiment with blended learning, but to date, research on the effects of…

  7. Co-continuous polycarbonate/ABS blends

    NARCIS (Netherlands)

    Inberg, J.P.F.; Gaymans, R.J.

    2002-01-01

    Co-continuous PC/ABS (50/50) blends were studied with a variable polybutadiene (PB) content (0–40%) in ABS. Polycarbonate (PC), styrene-acrylonitrile (SAN) and PB were blended in two steps using a twin screw extruder. Rectangular bars were injection moulded and notched Izod impact tested at

  8. Structuring of Interface-Modified Polymer Blends

    DEFF Research Database (Denmark)

    Lyngaae-Jørgensen, Jørgen

    1999-01-01

    The paper treats the case where blends of polystyrene (PS), poly (dimethylsiloxane) (PDMS) and a diblock copolymer of PS and PDMS are used as model materials. This modelsystem is predicted to be "stable" in discrete blends in simple shear flow. Stable in the sence that the block copolymer can not...

  9. Crystal Growth of Hen Egg-White Lysozyme (HEWL) under Various Gravity Conditions

    Science.gov (United States)

    Pan, Weichun; Xu, Jin; Tsukamoto, Katsuo; Koizumi, Masako; Yamazaki, Tomoya; Zhou, Ru; Li, Ang; Fu, Yuying

    2013-08-01

    Motivated by the enhancement of protein quality under microgravity condition, the behaviors of crystal growth under various gravity conditions have been monitored via Foton Satellite and parabolic flight. We found that the normal growth rate and the step velocity would be enhanced only at high protein concentration. Although the difference of diffusion between monomer lysozyme molecule and main impurity species in HWEL dimer may be able to explain this enhancement in long period at high protein concentration, it is not valid at low lysozyme concentration and it can't explain the results obtained by parabolic flight, in which microgravity condition maintained only about 20 s. In order to compromise this contradiction, cluster, universal existing in protein solution, has been picked up. The dynamic light scattering technique figured out dimer is served as the seed for cluster formation. Due to its large size, cluster keeps still under microgravity. Via this mechanism, the purification of lysozyme above crystal surface has been achieved. We also found the two supergravity (˜1.5 g) periods immediately before and after microgravity period have different effects on the step velocity. The pre-MG period depresses the step velocity while the post-MG enhances it. This odd phenomenon ascribes to two factors: (1) the flow rate modification and (2) the purity of protein solution immediate above crystal surface.

  10. Effect of sulfoxides on the thermal denaturation of hen lysozyme: A calorimetric and Raman study

    Science.gov (United States)

    Torreggiani, A.; Di Foggia, M.; Manco, I.; De Maio, A.; Markarian, S. A.; Bonora, S.

    2008-11-01

    A multidisciplinary study of the thermal denaturation of lysozyme in the presence of three sulfoxides with different length in hydrocarbon chain (DMSO, DESO, and DPSO) was carried out by means of DSC, Raman spectroscopy, and SDS-PAGE techniques. In particular, the Td and Δ H values obtained from the calorimetric measurements showed that lysozyme is partially unfolded by sulfoxides but most of the conformation holds native state. The sulfoxide denaturing ability increases in the order DPSO > DESO > DMSO. Moreover, only DMSO and DESO have a real effect in preventing the heat-induced inactivation of the protein and their maximum heat-protective ability is reached when the DMSO and DESO amount is ⩾25% w/w. The sulfoxide ability to act as effective protective agents against the heat-induced inactivation was confirmed by the protein analysis. The enzymatic activity, as well as the SDS-PAGE analysis, suggested that DESO, having a low hydrophobic character and a great ability to stabilise the three-dimensional water structure, is the most heat-protective sulfoxide. An accurate evaluation of the heat-induced conformational changes of the lysozyme structure before and after sulfoxide addition was obtained by the analysis of the Raman spectra. The addition of DMSO or DESO in low concentration resulted to sensitively decrease the heat-induced structural modifications of the protein.

  11. Crystallization of lysozyme with (R)-, (S)- and (RS)-2-methyl-2, 4-pentanediol

    Energy Technology Data Exchange (ETDEWEB)

    Stauber, Mark [Yeshiva University, 2495 Amsterdam Avenue, New York, NY 10033-3312 (United States); Yeshiva University, 2495 Amsterdam Avenue, New York, NY 10033-3312 (United States); Jakoncic, Jean [Brookhaven National Laboratory, Building 725D, Upton, NY 11973-5000 (United States); Berger, Jacob; Karp, Jerome M.; Axelbaum, Ariel; Sastow, Dahniel [Yeshiva University, 2495 Amsterdam Avenue, New York, NY 10033-3312 (United States); Yeshiva University, 2495 Amsterdam Avenue, New York, NY 10033-3312 (United States); Buldyrev, Sergey V. [Yeshiva University, 2495 Amsterdam Avenue, New York, NY 10033-3312 (United States); Hrnjez, Bruce J. [Collegiate School, 260 West 78th Street, New York, NY 10024-6559 (United States); Asherie, Neer, E-mail: asherie@yu.edu [Yeshiva University, 2495 Amsterdam Avenue, New York, NY 10033-3312 (United States); Yeshiva University, 2495 Amsterdam Avenue, New York, NY 10033-3312 (United States)

    2015-03-01

    Crystallization of lysozyme with (R)-2-methyl-2, 4-pentanediol produces more ordered crystals and a higher resolution protein structure than crystallization with (S)-2-methyl-2, 4-pentanediol. The results suggest that chiral interactions with chiral additives are important in protein crystal formation. Chiral control of crystallization has ample precedent in the small-molecule world, but relatively little is known about the role of chirality in protein crystallization. In this study, lysozyme was crystallized in the presence of the chiral additive 2-methyl-2, 4-pentanediol (MPD) separately using the R and S enantiomers as well as with a racemic RS mixture. Crystals grown with (R)-MPD had the most order and produced the highest resolution protein structures. This result is consistent with the observation that in the crystals grown with (R)-MPD and (RS)-MPD the crystal contacts are made by (R)-MPD, demonstrating that there is preferential interaction between lysozyme and this enantiomer. These findings suggest that chiral interactions are important in protein crystallization.

  12. Carboxymethyl chitosan-poly(amidoamine) dendrimer core-shell nanoparticles for intracellular lysozyme delivery.

    Science.gov (United States)

    Zhang, Xiaoyang; Zhao, Jun; Wen, Yan; Zhu, Chuanshun; Yang, Jun; Yao, Fanglian

    2013-11-06

    Intracellular delivery of native, active proteins is challenging due to the fragility of most proteins. Herein, a novel polymer/protein polyion complex (PIC) nanoparticle with core-shell structure was prepared. Carboxymethyl chitosan-grafted-terminal carboxyl group-poly(amidoamine) (CM-chitosan-PAMAM) dendrimers were synthesized by amidation and saponification reactions. (1)H NMR was used to characterize CM-chitosan-PAMAM dendrimers. The TEM images and results of lysozyme loading efficiency indicated that CM-chitosan-PAMAM dendrimers could self-assemble into core-shell nanoparticles, and lysozyme was efficiently encapsulated inside the core of CM-chitosan-PAMAM dendrimer nanoparticles. Activity of lysozyme was completely inhibited by CM-chitosan-PAMAM Dendrimers at physiological pH, whereas it was released into the medium and exhibited a significant enzymatic activity in an acidic intracellular environment. Moreover, the CM-chitosan-PAMAM dendrimer nanoparticles did not exhibit significant cytotoxicity in the range of concentrations below 3.16 mg/ml. The results indicated that these CM-chitosan-PAMAM dendrimers have excellent properties as highly potent and non-toxic intracellular protein carriers, which would create opportunities for novel applications in protein delivery.

  13. Solvent interactions and protein dynamics in spin-labeled T4 lysozyme.

    Science.gov (United States)

    Stoica, I

    2004-06-01

    Aspects of T4 lysozyme dynamics and solvent interaction are investigated using atomically detailed Molecular Dynamics (MD) simulations. Two spin-labeled mutants of T4 lysozyme are analyzed (T4L-N40C and T4L-K48C), which have been found from electronic paramagnetic resonance (EPR) experiments to exhibit different mobilities at the site of spin probe attachment (N- and C-terminus of helix B, respectively). Similarities and differences in solvent distribution and diffusion around the spin label, as well as around exposed and buried residues within the protein, are discussed. The purpose is to capture possible strong interactions between the spin label (ring) and solvent molecules, which may affect EPR lineshapes. The effect of backbone motions on the water density profiles is also investigated. The focus is on the domain closure associated with the T4 lysozyme hinge-bending motion, which is analyzed by Essential Dynamics (ED). The N-terminus of helix B is found to be a "hinge" residue, which explains the high degree of flexibility and motional freedom at this site.

  14. Effects of protein and phosphate buffer concentrations on thermal denaturation of lysozyme analyzed by isoconversional method.

    Science.gov (United States)

    Cao, X M; Tian, Y; Wang, Z Y; Liu, Y W; Wang, C X

    2016-07-03

    Thermal denaturation of lysozymes was studied as a function of protein concentration, phosphate buffer concentration, and scan rate using differential scanning calorimetry (DSC), which was then analyzed by the isoconversional method. The results showed that lysozyme thermal denaturation was only slightly affected by the protein concentration and scan rate. When the protein concentration and scan rate increased, the denaturation temperature (Tm) also increased accordingly. On the contrary, the Tm decreased with the increase of phosphate buffer concentration. The denaturation process of lysozymes was accelatated and the thermal stability was reduced with the increase of phosphate concentration. One part of degeneration process was not reversible where the aggregation occurred. The other part was reversible. The apparent activation energy (Ea) was computed by the isoconversional method. It decreased with the increase of the conversion ratio (α). The observed denaturation process could not be described by a simple reaction mechanism. It was not a process involving 2 standard reversible states, but a multi-step process. The new opportunities for investigating the kinetics process of protein denaturation can be supplied by this novel isoconversional method.

  15. Comparison of two codon optimization strategies enhancing recombinant Sus scrofa lysozyme production in Pichia pastoris.

    Science.gov (United States)

    Zhu, D; Cai, G; Wu, D; Lu, J

    2015-05-16

    Lysozyme has played an important role in animal feed additive industry, food additive industry and biological engineering. For improving expression efficiency of recombinant lysozyme from Sus scrofa, two genes respectively designed by the most used codon optimization strategies, "one amino acid one codon" and "codon randomization", were synthesized and expressed in Pichia pastoris X—33. At shaking flask level, Sus scrofa lysozyme (SSL) under two conditions had a highest activity of 153.33±10.41 and 538.33±15.18 U/mL after a 5 days induction of 1% methanol, with secreted protein concentration 80.03±1.94 and 239.60±4.16 mg/L, respectively. Compared with the original SSL gene, the expression of optimized SSL gene by the second strategy showed a 2.6 fold higher level, while the first method had no obvious improvement in production. In total secreted protein, the proportions of recombinant SSL encoded by the original gene, first method optimized gene and the second—strategy optimized one were 75.06±0.25%, 74.56±0.14% and 79.00±0.14%, respectively, with the same molecular weight about 18 kDa, optimum acidity pH 6.0 and optimum temperature 35degC.

  16. Purification and Characterization of Recombinant Human Lysozyme from Eggs of Transgenic Chickens.

    Science.gov (United States)

    Wu, Hanyu; Cao, Dainan; Liu, Tongxin; Zhao, Jianmin; Hu, Xiaoxiang; Li, Ning

    2015-01-01

    Transgenic chickens as bioreactors have several advantages, such as the simple establishment procedure, correct glycosylation profile of expressed proteins, etc. Lysozyme is widely used in food industry, livestock farming, and medical field as a replacement of antibiotics because of its antibacterial and complement system-modulating activity. In this study, we used RT-PCR, Western blot, and immunofluorescence to detect the expression of recombinant human lysozyme (rhLY) in the transgenic chicken. We demonstrated that the transgene of rhLY was genetically stable across different generations. We next optimized the purification procedure of rhLY from the transgenic eggs by utilizing two steps of cation-exchange chromatography and one gel-filtration chromatography. About 6 mg rhLY with the purity exceeding 90% was obtained from ten eggs, and the purification efficiency was about 75%. The purified rhLY had similar physicochemical and biological properties in molecular mass and antibacterial activity compared to the commercial human lysozyme. Additionally, both of them exhibited thermal stability at 60°C and tolerated an extensive pH range of 2 to 11. In conclusion, our study proved that the transgenic chickens we have previously generated were genetically stable and suitable for the production of active rhLY. We also provided a pipeline for purifying the recombinant proteins from transgenic eggs, which could be useful for other studies.

  17. Purification and Characterization of Recombinant Human Lysozyme from Eggs of Transgenic Chickens.

    Directory of Open Access Journals (Sweden)

    Hanyu Wu

    Full Text Available Transgenic chickens as bioreactors have several advantages, such as the simple establishment procedure, correct glycosylation profile of expressed proteins, etc. Lysozyme is widely used in food industry, livestock farming, and medical field as a replacement of antibiotics because of its antibacterial and complement system-modulating activity. In this study, we used RT-PCR, Western blot, and immunofluorescence to detect the expression of recombinant human lysozyme (rhLY in the transgenic chicken. We demonstrated that the transgene of rhLY was genetically stable across different generations. We next optimized the purification procedure of rhLY from the transgenic eggs by utilizing two steps of cation-exchange chromatography and one gel-filtration chromatography. About 6 mg rhLY with the purity exceeding 90% was obtained from ten eggs, and the purification efficiency was about 75%. The purified rhLY had similar physicochemical and biological properties in molecular mass and antibacterial activity compared to the commercial human lysozyme. Additionally, both of them exhibited thermal stability at 60°C and tolerated an extensive pH range of 2 to 11. In conclusion, our study proved that the transgenic chickens we have previously generated were genetically stable and suitable for the production of active rhLY. We also provided a pipeline for purifying the recombinant proteins from transgenic eggs, which could be useful for other studies.

  18. Introduction of Ca(2+)-binding amino-acid sequence into the T4 lysozyme.

    Science.gov (United States)

    Leontiev, V V; Uversky, V N; Permyakov, E A; Murzin, A G

    1993-03-05

    The 51-62 loop of T4 phage lysozyme was altered by site-directed mutagenesis to obtain maximal homology with the typical EF-hand motif. A Ca(2+)-binding site was designed and created by replacing both Gly-51 and Asn-53 with aspartic acid. The mutant T4 lysozyme (G51D/N53D) was expressed in Escherichia coli. The activity of the G51D/N53D-mutant was about 60% of that of the wild-type protein. This mutant can bind Ca2+ ions specifically, while the effective dissociation constant was essentially greater than that of the EF-hand proteins. Stability of the G51D/N53D-mutant apo-form to urea- or temperature-induced denaturation was the same as that of the wild-type protein. In the presence of Ca2+ ions in solution the stability of the mutant T4 phage lysozyme was less than that of the wild-type protein. It is suggested that the binding of Ca2+ by the mutant is accompanied by the considerable conformational changes in the 'corrected' loop, which can lead to the Ca(2+)-induced destabilization of the protein.

  19. Mechanistic studies on the release of lysozyme from twin-screw extruded lipid implants.

    Science.gov (United States)

    Sax, Gerhard; Winter, Gerhard

    2012-10-28

    The influence of lipid melting on the in-vitro release of lysozyme from twin-screw extruded lipid implants was investigated. Triglyceride based implants were prepared by admixing of glycerol tristearin and various low melting lipids and subsequent twin-screw extrusion (tsc-extrusion) of these mixtures at moderate temperatures. Lysozyme was embedded as model protein and PEG 4000 or PEG 6000 was used as pore-forming excipient. By decreasing the amount of pore-forming agent from 40% to 0% lysozyme release became more sustained and the release kinetics changed from a matrix-type release profile to a linear release profile. Differential scanning calorimetry, X-ray diffraction and scanning electron microscopy measurements showed a change in implant structure upon long-term release (240 days) at 37 °C which was explained by partial matrix melting. In addition, partial melting of the implants was found to facilitate complete drug release at 37 °C whereas at 20 °C without partial melting 20% to 90% of the incorporated protein remained trapped in the implant matrix. In conclusion, partial melting of the implants during in-vitro release was found to be a major factor for the control of protein release from extruded implants and can be useful to trigger release, achieve in-vivo biodegradability and complete long-term protein release.

  20. Lysozyme complexes with thermo- and pH-responsive PNIPAM- b-PAA block copolymer

    Science.gov (United States)

    Pippa, Natassa; Meristoudi, Anastasia; Pispas, Stergios; Demetzos, Costas

    2017-02-01

    Lysozyme is an enzyme responsible for the damage of bacterial cell walls and is abundant in a number of secretions such as tears and human milk. In the present study, we investigated the structure, the physicochemical characteristics, and the temperature-responsiveness of lysozyme complexes with poly( N-isopropylacrylamide)- b-poly(acrylic acid) block polyelectrolyte in aqueous media. A gamut of light-scattering techniques and fluorescence spectroscopy were used in order to examine the complexation process, as well as the structure, solution behavior, and temperature response of the nanosized complexes. The concentration of copolymer polyelectrolyte was kept constant. The values of the scattering intensity, I 90, which is proportional to the mass of the species in solution, increased gradually as a function of C LYS, providing proof of the occurring complexation, while the size of the nanostructures decreased. The structure of the complexes became more open as the C LYS increased. The increase of the salinity did not affect the structural characteristics of the supramolecular nanoparticulate aggregates. On the other hand, the physicochemical and structural characteristics of the complexes changed upon increasing temperature, and the changes depended on the initial ratio block polyelectrolyte/lysozyme. The knowledge on developing block polyelectrolyte/protein complexes through electrostatic interactions, obtained from this investigation, may be applied to the design of nutraceuticals.

  1. Rodlike Complexes of a Polyelectrolyte (Hyaluronan) and a Protein (Lysozyme) observed by SANS

    CERN Document Server

    Boué, François; Cousin, Fabrice; Grillo, Isabelle; Morfin, Isabelle; 10.1021/bm100861g

    2012-01-01

    We study by Small Angle Neutron Scattering (SANS) the structure of Hyaluronan -Lysozyme complexes. Hyaluronan (HA) is a polysaccharide of 9 nm intrinsic persistence length that bears one negative charge per disaccharide monomer (Mmol = 401.3 g/mol); two molecular weights, Mw = 6000 and 500 000 Da were used. The pH was adjusted at 4.7 and 7.4 so that lysozyme has a global charge of +10 and + 8 respectively. The lysozyme concentration was varied from 3 to 40 g/L, at constant HA concentration (10 g/L). At low protein concentration, samples are monophasic and SANS experiments reveal only fluctuations of concentration although, at high protein concentration, clusters are observed by SANS in the dense phase of the diphasic samples. In between, close to the onset of the phase separation, a distinct original scattering is observed. It is characteristic of a rod-like shape, which could characterize "single" complexes involving one or a few polymer chains. For the large molecular weight (500 000) the rodlike rigid doma...

  2. Variations of serum and mucus lysozyme activity and total protein content in the male and female Caspian kutum (Rutilus frisii kutum, Kamensky 1901) during reproductive period.

    Science.gov (United States)

    Ghafoori, Zomorod; Heidari, Behrooz; Farzadfar, Fariba; Aghamaali, Mahmoudreza

    2014-03-01

    Serum and mucus lysozyme were measured in male and female Caspian kutum (Rutilus frisii kutum) under seasonal temperature, gonadal growth and reproductive migration. Significant difference with almost similar trend in serum and mucus lysozyme of the female Caspian kutum in sampling time and ovarian growth was observed. However, while there was no significant difference in serum lysozyme of the male specimen in sampling time and testicular growth, significant variations was observed in mucus lysozyme. In addition, there was significant difference in mucus total protein both for male and female specimens. The effectiveness ratio of factors on lysozyme variations followed in descending order by seasonal temperature (main factor), reproductive activity and migration with negligible effect and the lysozyme level was not significantly different in male and female Caspian kutum.

  3. Descriptors for antimicrobial peptides

    DEFF Research Database (Denmark)

    Jenssen, Håvard

    2011-01-01

    Introduction: A frightening increase in the number of isolated multidrug resistant bacterial strains linked to the decline in novel antimicrobial drugs entering the market is a great cause for concern. Cationic antimicrobial peptides (AMPs) have lately been introduced as a potential new class...... examples of different peptide QSAR studies, this review highlights some of the missing links and illuminates some of the questions that would be interesting to challenge in a more systematic fashion. Expert opinion: Computer-aided peptide QSAR using molecular descriptors may provide the necessary edge...

  4. Study on combustion characteristics of blended coals

    Institute of Scientific and Technical Information of China (English)

    LI Yonghua; WANG Chunbo; CHEN Hongwei

    2007-01-01

    Power plants in China have to burn blended coal instead of one specific coal for a variety of reasons.So it is of great necessity to investigate the combustion of blended coals.Using a test rig with a capacity of 640 MJ/h with an absolute milling system and flue gas online analysis system,characteristics such as burnout,slag,and pollution of some blended coals were investigated.The ratio of coke and slag as a method of distinguishing coal slagging characteristic was introduced.The results show that the blending of coal has some effect on NOx but there is no obvious rule.SOx emission can be reduced by blending low sulfur coal.

  5. Compatibilizing Bulk Polymer Blends by using Organoclays

    Energy Technology Data Exchange (ETDEWEB)

    Si, Mayu; Araki, Tohru; Ade, Harald; Kilcoyne, A.L.D.; Fischer,Robert; Sokolov, Jonathan C.; Rafailovich, Miriam H.

    2006-03-28

    We have studied the morphology of blends of PS/PMMA,PC/SAN24, and PMMA/EVA and compared the morphologies with and withoutmodified organoclay Cloisite 20A or Cloisite 6A clays. In each case wefound a large reduction in domains size and the localization of the clayplatelets along the interfaces of the components. The increasedmiscibility was accompanied in some cases, with the reduction of thesystem from multiple values of the glass transition temperatures to one.In addition, the modulus of all the systems increased significantly. Amodel was proposed where it was proposed that in-situ grafts were formingon the clay surfaces during blending and the grafts then had to belocalized at the interfaces. This blending mechanism reflects thecomposition of the blend and is fairly nonspecific. As a result, this maybe a promising technology for use in processing recycled blends where thecomposition is often uncertain and price is of generalconcern.

  6. Maternally derived egg hormones, antibodies and antimicrobial proteins: common and different pathways of maternal effects in Japanese quail.

    Science.gov (United States)

    Okuliarova, Monika; Kankova, Zuzana; Bertin, Aline; Leterrier, Christine; Mostl, Erich; Zeman, Michal

    2014-01-01

    Avian eggs contain a variety of maternally-derived substances that can influence the development and performance of offspring. The levels of these egg compounds vary in relation to environmental and genetic factors, but little is known about whether there are correlative links between maternal substances in the egg underlying common and different pathways of maternal effects. In the present study, we investigated genetically determined variability and mutually adjusted deposition of sex hormones (testosterone-T, androstenedione-A4 and progesterone-P4), antibodies (IgY) and antimicrobial proteins (lysozyme) in eggs of Japanese quail (Coturnix japonica). We used different genetic lines that were independently selected for yolk T concentrations, duration of tonic immobility and social reinstatement behaviour, since both selections for behavioural traits (fearfulness and social motivation, respectively) produced considerable correlative responses in yolk androgen levels. A higher selection potential was found for increased rather than decreased yolk T concentrations, suggesting that there is a physiological minimum in egg T levels. Line differences in yolk IgY concentrations were manifested within each selection experiment, but no consistent inter-line pattern between yolk IgY and T was revealed. On the other hand, a consistent inverse inter-line pattern was recorded between yolk IgY and P4 in both selections for behavioural traits. In addition, selections for contrasting fearfulness and social motivation were associated with changes in albumen lysozyme concentrations and an inverse inter-line pattern between the deposition of yolk IgY and albumen lysozyme was found in lines selected for the level of social motivation. Thus, our results demonstrate genetically-driven changes in deposition of yolk T, P4, antibodies and albumen lysozyme in the egg. This genetic variability can partially explain mutually adjusted maternal deposition of sex hormones and immune

  7. Antimicrobial resistance challenged with metal-based antimicrobial macromolecules.

    Science.gov (United States)

    Abd-El-Aziz, Alaa S; Agatemor, Christian; Etkin, Nola

    2017-02-01

    Antimicrobial resistance threatens the achievements of science and medicine, as it deactivates conventional antimicrobial therapeutics. Scientists respond to the threat by developing new antimicrobial platforms to prevent and treat infections from these resistant strains. Metal-based antimicrobial macromolecules are emerging as an alternative to conventional platforms because they combine multiple mechanisms of action into one platform due to the distinctive properties of metals. For example, metals interact with intracellular proteins and enzymes, and catalyse various intracellular processes. The macromolecular architecture offers a means to enhance antimicrobial activity since several antimicrobial moieties can be conjugated to the scaffold. Further, these macromolecules can be fabricated into antimicrobial materials for contact-killing medical implants, fabrics, and devices. As volatilization or leaching out of the antimicrobial moieties from the macromolecular scaffold is reduced, these medical implants, fabrics, and devices can retain their antimicrobial activity over an extended period. Recent advances demonstrate the potential of metal-based antimicrobial macromolecules as effective platforms that prevent and treat infections from resistant strains. In this review these advances are thoroughly discussed within the context of examples of metal-based antimicrobial macromolecules, their mechanisms of action and biocompatibility. Copyright © 2016 Elsevier Ltd. All rights reserved.

  8. Inheritance of the lysozyme inhibitor Ivy was an important evolutionary step by Yersinia pestis to avoid the host innate immune response.

    Science.gov (United States)

    Derbise, Anne; Pierre, François; Merchez, Maud; Pradel, Elizabeth; Laouami, Sabrina; Ricard, Isabelle; Sirard, Jean-Claude; Fritz, Jill; Lemaître, Nadine; Akinbi, Henry; Boneca, Ivo G; Sebbane, Florent

    2013-05-15

    Yersinia pestis (the plague bacillus) and its ancestor, Yersinia pseudotuberculosis (which causes self-limited bowel disease), encode putative homologues of the periplasmic lysozyme inhibitor Ivy and the membrane-bound lysozyme inhibitor MliC. The involvement of both inhibitors in virulence remains subject to debate. Mutants lacking ivy and/or mliC were generated. We evaluated the mutants' ability to counter lysozyme, grow in serum, and/or counter leukocytes; to produce disease in wild-type, neutropenic, or lysozyme-deficient rodents; and to induce host inflammation. MliC was not required for lysozyme resistance and the development of plague. Deletion of ivy decreased Y. pestis' ability to counter lysozyme and polymorphonuclear neutrophils, but it did not affect the bacterium's ability to grow in serum or resist macrophages. Y. pestis lacking Ivy had attenuated virulence, unless animals were neutropenic or lysozyme deficient. The Ivy mutant induced inflammation to a degree similar to that of the parental strain. Last, Y. pseudotuberculosis did not require Ivy to counter lysozyme and for virulence. Ivy is required to counter lysozyme during infection, but its role as a virulence factor is species dependent. Our study also shows that a gene that is not necessary for the virulence of an ancestral bacterium may become essential in the emergence of a new pathogen.

  9. Structural, Functional and Phylogenetic Analysis of Sperm Lysozyme-Like Proteins.

    Science.gov (United States)

    Kalra, Shalini; Pradeep, Mangottil Ayyappan; Mohanty, Ashok K; Kaushik, Jai K

    2016-01-01

    Sperm lysozyme-like proteins belonging to c-type lysozyme family evolved in multiple forms. Lysozyme-like proteins, viz., LYZL2, LYZL3 or SLLP1, LYZL4, LYZL5 and LYZL6 are expressed in the testis of mammals. Not all members of LYZL family have been uniformly and unambiguously identified in the genome and proteome of mammals. Some studies suggested a role of SLLP1 and LYZL4 in fertilization; however, the function of other LYZL proteins is unknown. We identified all known forms of LYZL proteins in buffalo sperm by LC-MS/MS. Cloning and sequence analysis of the Lyzl cDNA showed 38-50% identity at amino acid level among the buffalo LYZL paralogs, complete conservation of eight cysteines and other signature sequences of c-type lysozyme family. Catalytic residues in SLLP1, LYZL4 and LYZL5 have undergone replacement. The substrate binding residues showed significant variation in LYZL proteins. Residues at sites 62, 101, 114 in LYZL4; 101 in SLLP1; 37, 62, and 101 in LYZL6 were more variable among diverse species. Sites 63 and 108 occupied by tryptophan were least tolerant to variation. Site 37 also showed lower tolerance to substitution in SLLP1, LYZL4 and LYZL5, but more variable in non-testicular lysozymes. Models of LYZL proteins were created by homology modeling and the substrate binding pockets were analyzed in term of binding energies and contacting residues of LYZL proteins with tri-N-acetylglucosamine (NAG)3 in the A-B-C and B-C-D binding mode. Except LYZL6, LYZL proteins did not show significant difference in binding energies in comparison to hen egg white lysozyme in the A-B-C mode. (NAG)3 binding energy in the B-C-D mode was higher by 1.3-2.2 kcal/mol than in A-B-C mode. Structural analysis indicated that (NAG)3 was involved in making more extensive interactions including hydrogen bonding with LYZL proteins in B-C-D mode than in A-B-C mode. Despite large sequence divergence among themselves and with respect to c-type lysozymes, substrate binding residues as

  10. Animation of Antimicrobial Resistance

    Medline Plus

    Full Text Available ... En Español Search FDA Submit search Popular Content Home Food Drugs Medical Devices Radiation-Emitting Products Vaccines, ... Biologics Animal & Veterinary Cosmetics Tobacco Products Animal & Veterinary Home Animal & Veterinary Safety & Health Antimicrobial Resistance Animation of ...

  11. Antimicrobial Prophylaxis in Adults

    OpenAIRE

    Enzler, Mark J.; Berbari, Elie; Osmon, Douglas R.

    2011-01-01

    Antimicrobial prophylaxis is commonly used by clinicians for the prevention of numerous infectious diseases, including herpes simplex infection, rheumatic fever, recurrent cellulitis, meningococcal disease, recurrent uncomplicated urinary tract infections in women, spontaneous bacterial peritonitis in patients with cirrhosis, influenza, infective endocarditis, pertussis, and acute necrotizing pancreatitis, as well as infections associated with open fractures, recent prosthetic joint placement...

  12. Animation of Antimicrobial Resistance

    Medline Plus

    Full Text Available ... use of antimicrobial drugs will result in the development of resistant strains of bacteria, complicating clinician's efforts ... Português | Italiano | Deutsch | 日本語 | فارسی | English FDA Accessibility Careers FDA Basics FOIA No FEAR Act Site Map ...

  13. THE EFFECT OF BLENDING SEQUENCE ON PHASE MORPHOLOGY OF NYLON 6/ABS/SMA BLENDS

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The preparation process-dependent phase morphology of blends composed of nylon 6 and acryionitrile-butadienestyrene(ABS)over a composition range of 30-70 wt% using a styrene-maleic anhydride(SMA)copolymer as the compatibilizing agent with a constant content(5phr)was investigated.The results of the scanning electron microscope (SEM)observation revealed that compared with the binary blends of nylon 6 and ABS,the existence of SMA caused a composition shift of phase inversion to a higher weight fraction of nylon 6 when ABS was blended with the preblended nylon 6/SMA blend,while the co-continuous structures could be observed over a considerably narrower composition range when nylon 6 was blended with the pre-blended ABS/SMA blend.An examination through dynamic mechanical analysis (DMA)tests confirmed the results obtained with SEM.It is found that near the phase inversion region a remarkable change in the dynamic storage modulus(G')and the loss tangent(tanδ)appears.Moreover,the influence of blending sequence on the size of dispersed particles has been probed for uncompatibilized and compatibilized blends of nylon 6 and ABS over a wide range of compositions below or beyond the phase inversion points.For the blends of ABS dispersed in a nylon 6 matrix,little discernible effects of blending sequence on particle size could be observed.Furthermore,there exists a significant difference in morphologies of the blends prepared by nylon 6 particles dispersing in a ABS matrix in cases of different blending sequences used.Some possible factors responsible for the above asymmetric behaviors have been proposed.

  14. Arsenic alters transcriptional responses to Pseudomonas aeruginosa infection and decreases antimicrobial defense of human airway epithelial cells.

    Science.gov (United States)

    Goodale, Britton C; Rayack, Erica J; Stanton, Bruce A

    2017-09-15

    Arsenic contamination of drinking water and food threatens the health of hundreds of millions of people worldwide by increasing the risk of numerous diseases. Arsenic exposure has been associated with infectious lung disease in epidemiological studies, but it is not yet understood how ingestion of low levels of arsenic increases susceptibility to bacterial infection. Accordingly, the goal of this study was to examine the effect of arsenic on gene expression in primary human bronchial epithelial (HBE) cells and to determine if arsenic altered epithelial cell responses to Pseudomonas aeruginosa, an opportunistic pathogen. Bronchial epithelial cells line the airway surface, providing a physical barrier and serving critical roles in antimicrobial defense and signaling to professional immune cells. We used RNA-seq to define the transcriptional response of HBE cells to Pseudomonas aeruginosa, and investigated how arsenic affected HBE gene networks in the presence and absence of the bacterial challenge. Environmentally relevant levels of arsenic significantly changed the expression of genes involved in cellular redox homeostasis and host defense to bacterial infection, and decreased genes that code for secreted antimicrobial factors such as lysozyme. Using pathway analysis, we identified Sox4 and Nrf2-regulated gene networks that are predicted to mediate the arsenic-induced decrease in lysozyme secretion. In addition, we demonstrated that arsenic decreased lysozyme in the airway surface liquid, resulting in reduced lysis of Microccocus luteus. Thus, arsenic alters the expression of genes and proteins in innate host defense pathways, thereby decreasing the ability of the lung epithelium to fight bacterial infection. Copyright © 2017 Elsevier Inc. All rights reserved.

  15. Blending traditional and digital marketing

    Directory of Open Access Journals (Sweden)

    Raluca Dania TODOR

    2016-07-01

    Full Text Available It is a matter of fact that we are in the digital era and internet marketing and social media have a significant impact on the way consumers behave, companies do business and it is a must for companies to adapt to the new reality. Due to the fast evolution of the technology, the continuous increase in demand and supply, the supply chain elongation and the big amount of date, the only solution to face the major changes is the automation of all the processes. But even though the new era of communication is here, specialist suggest that companies should not ignore traditional methods, and to try to blend digital marketing with traditional campaigns in order to achieve their goals.

  16. Preparation and characterization of antimicrobial nano-hydroxyapatite composites

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Juhong [The Key Laboratory of Advanced Textile Materials and Manufacturing Technology of Ministry of Education, College of Materials and Textiles, Zhejiang Sci-Tech University, Hangzhou 310018 (China); Chu, Xiaobing [The First Affiliated Hospital, Zhejiang Chinese Medicine University, Hangzhou 310006 (China); Cai, Yurong [The Key Laboratory of Advanced Textile Materials and Manufacturing Technology of Ministry of Education, College of Materials and Textiles, Zhejiang Sci-Tech University, Hangzhou 310018 (China); Tong, Peijian [The First Affiliated Hospital, Zhejiang Chinese Medicine University, Hangzhou 310006 (China); Yao, Juming, E-mail: yaoj@zstu.edu.cn [The Key Laboratory of Advanced Textile Materials and Manufacturing Technology of Ministry of Education, College of Materials and Textiles, Zhejiang Sci-Tech University, Hangzhou 310018 (China)

    2014-04-01

    Deep infection of prosthesis is one of the most frequent complications after joint replacement. One of the most effective ways is to introduce directly some antibiotics in the local site of the surgery. In the present study, an antimicrobial composite has been fabricated using nano-hydroxyapatite particles as carriers for the antimicrobial drug of vancomycin hydrochloride (VAN) and the mixture of oxidation sodium alginate (OSA) and gelatin (GT) as a sticky matrix. Samples have been characterized using X-ray diffraction instrument (XRD), field emission scanning electron microscope (FE-SEM), transmission electron microscope (TEM) and Fourier transform infrared (FTIR) spectra, Brunauer–Emmett–Teller (BET) methods, the rotational rheometer and the texture analyzer. The release of VAN from nano-hydroxyapatite (nHAP) particles was detected by the ultraviolet–visible (UV–vis) spectrophotometer and then bactericidal property of the composite was evaluated using the Staphylococcus aureus (S. aureus) as a bacterial model. Experimental results showed that the composite possessed an adhesive property derived from the gel of OSA and GT, which implied that the composite could bond directly to the fracture surface of bones in surgery. Furthermore, VAN was loaded efficiently on the surface of nHAP particles and could be released slowly from these particles, which endowed the composite with an obvious and continuous antimicrobial performance. The sticky and antimicrobial composite may has a potential application in arthroplasty to overcome deep infection in a simple and direct manner. - Highlights: • A sticky and antimicrobial composite has been designed to overcome deep infection. • The composite was composed of antibiotic, antibiotic carrier and a viscous matrix. • The sticky matrix was obtained by blending of oxidation sodium alginate and gelatin. • Hydroxyapatite nanoparticle could be used as carrier to control release of antibiotic.

  17. Blended Learning in Action: A Practical Guide toward Sustainable Change

    Science.gov (United States)

    Tucker, Catlin R.; Wycoff, Tiffany; Green, Jason T.

    2017-01-01

    Blended learning has the power to reinvent education, but transitioning to a blended model is challenging. Blended learning requires a fundamentally new approach to learning as well as a new skillset for both teachers and school leaders. Loaded with research, examples, and resources, "Blended Learning in Action" demonstrates the…

  18. 动物源溶菌酶研究进展%Advance in Studies of Animal-borne Lysozyme

    Institute of Scientific and Technical Information of China (English)

    张鹏; 江明锋; 王永

    2012-01-01

    动物源溶菌酶是一种动物体内广泛存在的酶类,它可以水解细菌细胞壁肽聚糖中的β-1,4糖苷键,具有消化分解细菌、抑制外源微生物生长、增强机体免疫力的作用.目前溶菌酶已被用作研究蛋白功能、性质以及分子进化的模型.首先介绍了溶菌酶及其分子的晶体结构,溶菌酶基因及其蛋白研究进展,其次介绍了动物源溶菌酶的功能,包括溶菌酶生物学功能和重组蛋白功能活性,重点介绍了溶菌酶基因在转基因工程中的应用研究,最后对动物源溶菌酶研究进行了展望.研究动物源溶菌酶对于基础科学,并应用其转变成现实生产力具有重要的指导意义.%Lysozyme is a kind of muramidases that widespread in the animal in vivo, and can catalyze the hydrolysis of β-1, 4-glycosidic bonds between the N-acetylglucosamine and N-acetylmuramic acid in the peptidoglycan layer of bacterial cell walls. It has functions of the digestion and decomposition of bacteria, and inhibition of exogenous microbial growth, and enhancing immunity; and lysozyme has been a model protein for research in the function and the nature of the enzyme, and molecular evolution. Firstly, the lysozyme and its crystal structure and the advance in studies of lysozyme gene and its protein were introduced. Secondly, the functions of animal-borne lysozyme, including the biological functions of lysozyme and functional activities of recombinant proteins were introduced too,then the applied researches in lysozyme gene in transgenic engineering were focused on. Finally, the perspectives of animal-borne lysozyme were suggested. It' s very significant to research the animal-borne lysozyme because it' s helpful to understand the basic knowledge and to use it in the production.

  19. Relations between blended learning possibilities and teachers' approaches to blended learning

    DEFF Research Database (Denmark)

    Stenalt, Maria Hvid; Nielsen, Tobias Alsted; Bager-Elsborg, Anna

    Higher Education has embraced blended learning as a way of enhancing quality in teaching and helping students to learn. This presentation addresses relations between blended learning possiblities presented to teachers in a teacher training project and teachers’ approaches to blended learning. We...... suggest that in order to identify the level of impact of integrating technologies in teaching and learning, we need to understand the factors influencing approaches to design of courses for blended contexts. Participants in the teacher training project come from the Department of Law at Aarhus University......: • Optain locally-embedded knowledge about blended learning • Develop opportunities for law students to receive (more) feedback • Comply with strategic aims The results so far suggest that teachers provide a disciplinary perspective on the key dimensions of blended learning, which influences...

  20. Morphology Evolution of Polycarbonate-Polystyrene Blends During Compounding

    DEFF Research Database (Denmark)

    Chuai, Chengzhi; Almdal, Kristoffer; Johannsen, Ib;

    2001-01-01

    The morphology evolution of polycarbonate-polystyrene (PC/PS) blends during the compounding process in three blending methods of industrial relevance, namely melt blending, re-melt blending in a twin-screw extruder and tri-melt blending in an injection-moulding machine, was investigated using......-empirical model. The results show that the formation of co-continuous morphology strongly depends on blend composition and melt blending method, whereas the model prediction for phase inversion deviates from the experimental values. Further, we found that the initial mechanism of morphology evolution involves...

  1. Data supporting the effects of lysozyme on mRNA and protein expression in a colonic epithelial scratch wound model

    Directory of Open Access Journals (Sweden)

    Sarah K. Abey

    2017-04-01

    Full Text Available Colonic epithelial health is implicated in a host of gastrointestinal (GI diseases and disorders. Lysozyme is suspected to play a role in the ability of the epithelium to recover from injury (Abey et al., in press; Gallo, 2012; Rubio, 2014 [1–3]. Disrupted repair mechanisms may lead to delayed or ineffective recovery and disruptions to epithelial biology resulting in GI symptoms and altered barrier function (Peterson and Artis, 2014 [4]. The effect of lysozyme on the transcriptomic and proteomic profile of healthy colonic epithelial cells was investigated. Epithelial cells in culture were scratch wounded and treated with lysozyme. mRNA and protein profiles were simultaneously quantified in the same sample using a digital counting technology. Gene and protein expressions altered by the presence or absence of lysozyme are described in this article. Extensive statistical and bioinformatic analysis, and interpretation of the results can be found in “Lysozyme association with circulating RNA, extracellular vesicles, and chronic stress” (Abey et al., in press [1].

  2. Molecular investigation of the interaction between ionic liquid type gemini surfactant and lysozyme: A spectroscopic and computational approach.

    Science.gov (United States)

    Maurya, Jitendra Kumar; Mir, Muzaffar Ul Hassan; Singh, Upendra Kumar; Maurya, Neha; Dohare, Neeraj; Patel, Seema; Ali, Anwar; Patel, Rajan

    2015-07-01

    Herein, we are reporting the interaction of ionic liquid type gemini surfactant, 1,4-bis(3-dodecylimidazolium-1-yl) butane bromide ([C12-4-C12 im]Br2) with lysozyme by using Steady state fluorescence, UV-visible, Time resolved fluorescence, Fourier transform-infrared (FT-IR) spectroscopy techniques in combination with molecular modeling and docking method. The steady state fluorescence spectra suggested that the fluorescence of lysozyme was quenched by [C12-4-C12 im]Br2 through static quenching mechanism as confirmed by time resolved fluorescence spectroscopy. The binding constant for lysozyme-[C12-4-C12 im]Br2 interaction have been measured by UV-visible spectroscopy and found to be 2.541 × 10(5) M(-1). The FT-IR results show conformational changes in the secondary structure of lysozyme by the addition of [C12-4-C12 im]Br2. Moreover, the molecular docking study suggested that hydrogen bonding and hydrophobic interactions play a key role in the protein-surfactant binding. Additionally, the molecular dynamic simulation results revealed that the lysozyme-[C12-4-C12 im]Br2 complex reaches an equilibrium state at around 3 ns.

  3. Bacterial antimicrobial metal ion resistance.

    Science.gov (United States)

    Hobman, Jon L; Crossman, Lisa C

    2015-05-01

    Metals such as mercury, arsenic, copper and silver have been used in various forms as antimicrobials for thousands of years with until recently, little understanding of their mode of action. The discovery of antibiotics and new organic antimicrobial compounds during the twentieth century saw a general decline in the clinical use of antimicrobial metal compounds, with the exception of the rediscovery of the use of silver for burns treatments and niche uses for other metal compounds. Antibiotics and new antimicrobials were regarded as being safer for the patient and more effective than the metal-based compounds they supplanted. Bacterial metal ion resistances were first discovered in the second half of the twentieth century. The detailed mechanisms of resistance have now been characterized in a wide range of bacteria. As the use of antimicrobial metals is limited, it is legitimate to ask: are antimicrobial metal resistances in pathogenic and commensal bacteria important now? This review details the new, rediscovered and 'never went away' uses of antimicrobial metals; examines the prevalence and linkage of antimicrobial metal resistance genes to other antimicrobial resistance genes; and examines the evidence for horizontal transfer of these genes between bacteria. Finally, we discuss the possible implications of the widespread dissemination of these resistances on re-emergent uses of antimicrobial metals and how this could impact upon the antibiotic resistance problem. © 2014 The Authors.

  4. The application of composite polypeptide lysozyme on treatment of opsi-genes pericoronitis%复合多肽溶菌酶在智牙冠周炎治疗中的应用

    Institute of Scientific and Technical Information of China (English)

    萧雅一; 杨莉; 牟雁东

    2016-01-01

    Objective:To observe the synergistic antibacterial effect of composite polypeptide lysozyme in treating opsigenes pericoronitis and evaluate its clinical effect.Methods:This experiment was composed of two parts;the first part is in vitro bacteriostasis experiment,selecting the sensitive bacterium in opsigenes pericoronitis,including staphylococcus aureus,escherichia coli,pseudomonas aeruginosa,streptococcus mutan.Added the dilution of antibacterial peptides and human lysozyme by two times the gradient dilution method into 96 cell culture plate;after 24 hours culture in 37.0 ℃ constant temperature incubator,observed whether antibacterial pep-tides compound human lysozyme have synergistic antimicrobial effect or not.The second part is clinical experiment.Randomly divided patients into experimental group and control group,69 cases in each,the experimental group used compound lysozyme polypeptide mouthwash;the control group used compound chlorhexidine gargle.After three consecutive days of follow-up,which is before treatment, the first and second day after treatment,counted the colony of periodontal secretions and evaluated clinical indicators.Results:The com-bined use of antibacterial peptides and human lysozyme have synergistic antimicrobial effects to standard strains of staphylococcus au-reus,escherichia coli,pseudomonas aeruginosa,streptococcus mutans,and parts of resistant strains of staphylococcus aureus,escherichi-a coli,pseudomonas aeruginosa.Conclusion:Antimicrobial peptides complex human lysozyme has good synergistic effect on some bacte-ria caused opsigenes pericoronitis,compounded as gargle water can effectively reduce the blind pouch bacterial reproduction,alleviate the symptoms of opsigenes pericoronitis.%目的:观察复合多肽溶菌酶在智牙冠周炎治疗中的协同抑菌效果和临床疗效分析。方法:研究分为两部分,第一部分为体外抑菌实验,选择智牙冠周炎内常见的金黄色葡萄球菌、大肠杆菌、

  5. Antimicrobial Performance of Two Different Packaging Materials on the Microbiological Quality of Fresh Salmon

    Directory of Open Access Journals (Sweden)

    Manuela Rollini

    2016-01-01

    Full Text Available In the present research the antimicrobial activity of two active packaging materials on the spoilage microbiota of fresh salmon fillets was tested. A PET-coated film (PET: Polyethylene Terephthalate containing lysozyme and lactoferrin was tested in parallel with a carvacrol-coextruded multilayer film. Salmon fillet samples were stored up to four days at 0 and 5 °C, comparatively. The carvacrol multilayer film was found effective in preventing mesophiles and psychrotrophs at shorter storage time and at lower temperature (4.0 compared to 5.0 log CFU/g in the control sample—CFU: Colony Forming Units. Lysozyme/lactoferrin-coated PET was instead efficient in decreasing H2S-producing bacteria at longer storage time and higher temperature (2.7 instead of 4.7 log CFU/g in the control sample. Even if is not intended as a way to “clean” a contaminated food product, an active package solution can indeed contribute to reducing the microbial population in food items, thus lowering the risk of food-related diseases.

  6. NESDIS Blended Total Precipitable Water (TPW) Products

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The blended Total Precipitable Water (TPW) product is derived from multiple sensors/satellites. The Percentage of TPW normal (PCT), or TPW anomaly, shows the...

  7. Investigating engagement in a blended learning course

    Directory of Open Access Journals (Sweden)

    Hui Yong Tay

    2016-12-01

    Full Text Available Proponents of a blended course paint an ideal picture of participants leisurely learning and reflecting on how they can apply their new knowledge. The reality is of course much more complex, especially in the lives of working adults. This study sought to understand the complexity better through analysing the experience of 123 participants enrolled in the 9-h in-service blended course. In particular, it investigated participants' engagement by examining their experience as they interacted with elements of the blended environment. The mixed methods approach was employed with quantitative data from the course analytics and responses from the 34 participants who returned the evaluation questionnaire at the end of the course. This was complemented with one-to-one interviews with 10 participants. The findings suggest that designers of blended professional development courses should bear in mind the characteristics of both the learner and the online platform to achieve greater cognitive, behavioural and social engagement.

  8. Strengths Weaknesses Opportunities and Threats of Blended ...

    African Journals Online (AJOL)

    Blended learning (BL), defined as “the thoughtful integration of classroom .... Students learned some of the material independently and helped them to apply the .... awareness of participants' own knowledge gaps, which leads to deeper ...

  9. Blending Parametric Patches with Subdivision Surfaces

    Institute of Scientific and Technical Information of China (English)

    李桂清; 李华

    2002-01-01

    In this paper the problem of blending parametric surfaces using subdivision patches is discussed. A new approach, named removing-boundary, is presented to generate piecewise-smooth subdivision surfaces through discarding the outmost quadrilaterals of the open meshes derived by each subdivision step. Then the approach is employed both to blend parametric bicubic B-spline surfaces and to fill n-sided holes. It is easy to produce piecewisesmooth subdivision surfaces with both convex and concave corners on the boundary, and limit surfaces are guaranteed to be C2 continuous on the boundaries except for a few singular points by the removing-boundary approach. Thus the blending method is very efficient and the blending surface generated is of good effect.

  10. Thin films of photoactive polymer blends.

    Science.gov (United States)

    Ruderer, Matthias A; Metwalli, Ezzeldin; Wang, Weinan; Kaune, Gunar; Roth, Stephan V; Müller-Buschbaum, Peter

    2009-03-09

    The morphology inside photoactive blended films of two conjugated homopolymers poly [(1-methoxy)-4-(2-ethylhexyloxy)-p-phenylene-vinylene] (MEH-PPV) and poly(3-hexylthiophene-2,5-diyl) (P3HT) is investigated. For both homopolymers a linear dependence of the installed film thickness from the concentration of the polymer solution used in spin coating is probed. This dependence allows preparation of an efficient series of blended films with constant thickness and different blending ratios. Information about the lateral structure inside the films is gained from grazing incidence small angle X-ray scattering. At the calculated critical blending ratio the smallest lateral separation between adjacent domains is found representing the highest surface contact between both homopolymers in the films. The presence of wetting layers at both interfaces as detected with X-ray reflectivity and atomic force microscopy is promising for photovoltaic applications. UV/Vis spectroscopy complements the structural investigation.

  11. Combating antimicrobial resistance: antimicrobial stewardship program in Taiwan.

    Science.gov (United States)

    Tseng, Shu-Hui; Lee, Chun-Ming; Lin, Tzou-Yien; Chang, Shan-Chwen; Chuang, Yin-Ching; Yen, Muh-Yong; Hwang, Kao-Pin; Leu, Hsieh-Shong; Yen, Che-Chieh; Chang, Feng-Yee

    2012-04-01

    Multi-drug-resistant organisms are increasingly recognized as a global public health issue. Healthcare-associated infection and antimicrobial resistance are also current challenges to the treatment of infectious diseases in Taiwan. Government health policies and the health care systems play a crucial role in determining the efficacy of interventions to contain antimicrobial resistance. National commitment to understand and address the problem is prerequisite. We analyzed and reviewed the antibiotic resistance related policies in Taiwan, USA, WHO and draft antimicrobial stewardship program to control effectively antibiotic resistance and spreading in Taiwan. Antimicrobial stewardship program in Taiwan includes establishment of national inter-sectoral antimicrobial stewardship task force, implementing antimicrobial-resistance management strategies, surveillance of HAI and antimicrobial resistance, conducting hospital infection control, enforcement of appropriate regulations and audit of antimicrobial use through hospital accreditation, inspection and national health insurance payment system. No action today, no cure tomorrow. Taiwan CDC would take a multifaceted, evidence-based approach and make every effort to combat antimicrobial resistance with stakeholders to limit the spread of multi-drug resistant strains and to reduce the generation of antibiotic resistant bacteria in Taiwan.

  12. IgG, IgA, and lysozyme in Martina Franca donkey jennies and their foals.

    Science.gov (United States)

    Veronesi, Maria C; Dall'Ara, Paola; Gloria, Alessia; Servida, Francesco; Sala, Elisabetta; Robbe, Domenico

    2014-04-01

    Because immune transfer from jenny to donkey foal is mostly unknown, the aim of the present study was to evaluate, from 5 days before to 10 days after foaling, immunoglobulin (Ig)G, IgA, and lysozyme peripartal concentrations in serum and mammary secretions of 10 healthy, spontaneously foaling Martina Franca jennies and in serum of their mature, viable, healthy foals, in the first 10 days after birth. The results showed that, in jennies, mammary secretion of IgG levels (ranging between 16 and 75 mg/mL) and IgA (0.9-2 mg/mL), and IgG (6.8-13.5 mg/mL) and IgA (0.5-2.4 mg/mL) serum concentrations were not different along the time of study. Also, IgG concentrations in serum of foals did not show significant differences although a high level was observed at 12 hours after birth (8 mg/mL), and IgA concentrations in serum of foals did not show any significant difference, although a high level was observed at 12 hours after birth (1.2 mg/mL). Lysozyme increased significantly at Day 2 after parturition in mammary secretions of jennies (551.9 μg/mL) and at 12 hours in serum of foals (25.9 μg/mL). The study demonstrated that the pattern of passive immune transfer in donkey foals seems to be similar to that reported for the horse foal, with IgG predominating IgA in serum and mammary secretions of the jenny and also in serum of foals. The most significant early increase in foals' serum concerns lysozyme, which probably plays an important role in the innate immunity of the donkey foal in the first challenging hours after birth.

  13. Two goose-type lysozymes in Mytilus galloprovincialis: possible function diversification and adaptive evolution.

    Directory of Open Access Journals (Sweden)

    Qing Wang

    Full Text Available Two goose-type lysozymes (designated as MGgLYZ1 and MGgLYZ2 were identified from the mussel Mytilus galloprovincialis. MGgLYZ1 mRNA was widely expressed in the examined tissues and responded sensitively to bacterial challenge in hemocytes, while MGgLYZ2 mRNA was predominately expressed and performed its functions in hepatopancreas. However, immunolocalization analysis showed that both these lysozymes were expressed in all examined tissues with the exception of adductor muscle. Recombinant MGgLYZ1 and MGgLYZ2 could inhibit the growth of several Gram-positive and Gram-negative bacteria, and they both showed the highest activity against Pseudomonas putida with the minimum inhibitory concentration (MIC of 0.95-1.91 µM and 1.20-2.40 µM, respectively. Protein sequences analysis revealed that MGgLYZ2 had lower isoelectric point and less protease cutting sites than MGgLYZ1. Recombinant MGgLYZ2 exhibited relative high activity at acidic pH of 4-5, while MGgLYZ1 have an optimum pH of 6. These results indicated MGgLYZ2 adapted to acidic environment and perhaps play an important role in digestion. Genomic structure analysis suggested that both MGgLYZ1 and MGgLYZ2 genes are composed of six exons with same length and five introns, indicating these genes were conserved and might originate from gene duplication during the evolution. Selection pressure analysis showed that MGgLYZ1 was under nearly neutral selection while MGgLYZ2 evolved under positive selection pressure with three positively selected amino acid residues (Y(102, L(200 and S(202 detected in the mature peptide. All these findings suggested MGgLYZ2 perhaps served as a digestive lysozyme under positive selection pressure during the evolution while MGgLYZ1 was mainly involved in innate immune responses.

  14. Cloning, purification and comparative characterization of two digestive lysozymes from Musca domestica larvae

    Directory of Open Access Journals (Sweden)

    F.C. Cançado

    2008-11-01

    Full Text Available cDNA coding for two digestive lysozymes (MdL1 and MdL2 of the Musca domestica housefly was cloned and sequenced. MdL2 is a novel minor lysozyme, whereas MdL1 is the major lysozyme thus far purified from M. domestica midgut. MdL1 and MdL2 were expressed as recombinant proteins in Pichia pastoris, purified and characterized. The lytic activities of MdL1 and MdL2 upon Micrococcus lysodeikticus have an acidic pH optimum (4.8 at low ionic strength (μ = 0.02, which shifts towards an even more acidic value, pH 3.8, at a high ionic strength (μ = 0.2. However, the pH optimum of their activities upon 4-methylumbelliferyl N-acetylchitotrioside (4.9 is not affected by ionic strength. These results suggest that the acidic pH optimum is an intrinsic property of MdL1 and MdL2, whereas pH optimum shifts are an effect of the ionic strength on the negatively charged bacterial wall. MdL2 affinity for bacterial cell wall is lower than that of MdL1. Differences in isoelectric point (pI indicate that MdL2 (pI = 6.7 is less positively charged than MdL1 (pI = 7.7 at their pH optima, which suggests that electrostatic interactions might be involved in substrate binding. In agreement with that finding, MdL1 and MdL2 affinities for bacterial cell wall decrease as ionic strength increases.

  15. Purification of Egg White Lysozyme from Indonesian Kampung Chicken and Ducks

    Directory of Open Access Journals (Sweden)

    Z. Wulandari

    2015-04-01

    Full Text Available Egg white lysozyme (EWL has considerably a wide functional protein exhibiting antibacterial activity mainly against Gram-positive bacteria. The EWL is widely applied in food industry and is considerably safe. Despite its high potency, EWL of Indonesian poultry has never been studied and exploited. This study was aimed to purify EWL from two Indonesian poultry: kampung chicken and Cihateup duck, and compared to egg of commercial laying hens. The eggs in this study were obtained from field laboratory of Faculty of Animal Science, Bogor Agricultural University (IPB and classified in AA quality based on the interior quality. First attempt to purify the EWL was performed by using ethanol precipitation yielding purified EWL which was still contaminated by other proteins, hence designated as partially purified EWL. Final concentrations of partially purified EWL of kampung chicken, commercial laying hens, and Cihateup duck were about 5800, 5400, and 5500 μg/mL, respectively. To confirm whether the use of ethanol in the purification affecting EWL antibacterial activities, the activities were examined against Staphylococcus aureus. It demonstrated that the partially purified EWL exhibited ability to inhibit S. aureus at 6 and 26 h suggesting that the method was feasible as it did not interfere EWL antibacterial activities. Yet, based on SDS-Page, purity was the issue in ethanol precipitation method. Further attempt using ion exchange chromatography at pH 10 successfully purified lysozyme as indicated by a single band corresponding to lysozyme size (~14 kD free from bands of other proteins. Altogether, a single step of ion exchange chromatography is sufficient and promising to isolate EWL from Indonesian poultry for various industrial purposes.

  16. Triclosan antimicrobial polymers

    OpenAIRE

    Petersen, Richard C.

    2016-01-01

    Triclosan antimicrobial molecular fluctuating energies of nonbonding electron pairs for the oxygen atom by ether bond rotations are reviewed with conformational computational chemistry analyses. Subsequent understanding of triclosan alternating ether bond rotations is able to help explain several material properties in Polymer Science. Unique bond rotation entanglements between triclosan and the polymer chains increase both the mechanical properties of polymer toughness and strength that are ...

  17. Antimicrobial Peptides in Echinoderms

    OpenAIRE

    Li, C; Haug, T; K Stensvåg

    2010-01-01

    Antimicrobial peptides (AMPs) are important immune effector molecules for invertebrates, including echinoderms, which lack a vertebrate-type adaptive immune system. Here we summarize the knowledge of such peptides in echinoderms. Strongylocins are a novel family of cysteine-rich AMPs, recently identified in the sea urchins, Strongylocentrotus droebachiensis and S. purpuratus. Although these molecules present diverse amino acid sequences, they share an identical cysteine arrangement pattern, d...

  18. Antimicrobial Modifications of Polymers

    OpenAIRE

    Sedlarik, Vladimir

    2013-01-01

    This chapter is focused on antimicrobial modifications of polymer materials intended for medical devices production. Firstly, a brief introduction into the field of medical application of polymers is presented. Considering the fact that polymer medical devices are often connected with occurrence of nosocomial infections, the next part refers to this phenomenon and its causes. One of the possibilities of reducing of the infection occurrence is aimed at polymer modification. It is a key topic o...

  19. Blended Interaction Spaces for Collaborative Design

    DEFF Research Database (Denmark)

    Dalsgaard, Peter; Halskov, Kim; Klokmose, Clemens Nylandsted

    During the past five years, we have explored the use, potentials and challenges of Blended Interaction spaces. In addition, we have a long background in developing and exploring methods for collaborative design. In this workshop paper, we give an overview of our work and present our visions...... and ongoing research in developing Blended Interaction spaces for collaborative design. We then identify key themes and challenges pertinent for the workshop....

  20. Sausage Blending Using Multiple Objective Linear Programming

    OpenAIRE

    Steuer, Ralph E.

    1984-01-01

    Single objective cost minimization linear programming models are used as computerized decision-aids in sausage manufacturing (hot dogs, bologna, salami, etc.). However, sausage blending is clearly a problem with multiple conflicting criteria (cost, color, fat, protein, moisture, etc.) Presented in this paper is a vector-maximum/filtering MOLP (multiple objective linear programming) methodology for use as an improved decision-making approach with single formula sausage blending problems.