WorldWideScience

Sample records for lysozyme naturally present

  1. 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.

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

    Directory of Open Access Journals (Sweden)

    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. 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.

  4. [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.

  5. Production and Application of Lysozyme-Gum Arabic Conjugate in Mayonnaise as a Natural Preservative and Emulsifier

    DEFF Research Database (Denmark)

    Hashemi, Marjan M.; Aminlari, Mahmoud; Forouzan, Mehdi M.

    2018-01-01

    Nowadays demand for food products made by natural sources is rising so fast. In this work Lysozyme (Lyz) was conjugated with gum Arabic (GA) in order to be applied in mayonnaise, at which the presence of both preservative and emulsifier is essential. Interestingly, the Lyz-GA conjugate exhibited...... improved functional properties and antibacterial activity. In order to approve the results of this study, the Lyz-GA conjugate was applied to mayonnaise as a natural preservative and emulsifier. Application of the Lzy-GA conjugate in mayonnaise expedited the death rate of both S. aureus and E. coli K-12...... elasticity in the mayonnaise. Mayonnaise including conjugates showed a linear rheological response and shear-thinning behavior. Sensory analysis of the mayonnaise with Lyz-GA conjugate was completely consistent with the commercial one. Taken together, our results suggest that conjugation of Lyz with GA made...

  6. 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.

  7. Natural deduction : sharing by presentation

    NARCIS (Netherlands)

    Loeb, Iris

    2007-01-01

    Part I of this thesis studies a fragment of natural deduction to which we have added the notion of sharing of subresults. This formalism is called 'deduction graphs'. We show some properties of cut-elimination on deduction graphs, like strong normalisation and confluence. We discuss connections with

  8. The nature of the present

    CERN Document Server

    Romero, Gustavo E

    2012-01-01

    The feeling of a moving present or `now' seems to form part of our most basic perceptions about reality. Such a present, however, is not reflected in any of our theories of the physical world. In this short note I argue for a tenseless view of time, where what we call `the present' is just an emergent secondary quality arising from the interaction of perceiving self-conscious individuals with their environment. I maintain that there is no flow of time, but just an ordered system of events.

  9. 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.

  10. An RNA aptamer possessing a novel monovalent cation-mediated fold inhibits lysozyme catalysis by inhibiting the binding of long natural substrates.

    Science.gov (United States)

    Padlan, Camille S; Malashkevich, Vladimir N; Almo, Steve C; Levy, Matthew; Brenowitz, Michael; Girvin, Mark E

    2014-04-01

    RNA aptamers are being developed as inhibitors of macromolecular and cellular function, diagnostic tools, and potential therapeutics. Our understanding of the physical nature of this emerging class of nucleic acid-protein complexes is limited; few atomic resolution structures have been reported for aptamers bound to their protein target. Guided by chemical mapping, we systematically minimized an RNA aptamer (Lys1) selected against hen egg white lysozyme. The resultant 59-nucleotide compact aptamer (Lys1.2minE) retains nanomolar binding affinity and the ability to inhibit lysozyme's catalytic activity. Our 2.0-Å crystal structure of the aptamer-protein complex reveals a helical stem stabilizing two loops to form a protein binding platform that binds lysozyme distal to the catalytic cleft. This structure along with complementary solution analyses illuminate a novel protein-nucleic acid interface; (1) only 410 Å(2) of solvent accessible surface are buried by aptamer binding; (2) an unusually small fraction (∼18%) of the RNA-protein interaction is electrostatic, consistent with the limited protein phosphate backbone contacts observed in the structure; (3) a single Na(+) stabilizes the loops that constitute the protein-binding platform, and consistent with this observation, Lys1.2minE-lysozyme complex formation takes up rather than displaces cations at low ionic strength; (4) Lys1.2minE inhibits catalysis of large cell wall substrates but not catalysis of small model substrates; and (5) the helical stem of Lys1.2minE can be shortened to four base pairs (Lys1.2minF) without compromising binding affinity, yielding a 45-nucleotide aptamer whose structure may be an adaptable protein binding platform.

  11. Natural Gas Engine Development Gaps (Presentation)

    Energy Technology Data Exchange (ETDEWEB)

    Zigler, B.T.

    2014-03-01

    A review of current natural gas vehicle offerings is presented for both light-duty and medium- and heavy-duty applications. Recent gaps in the marketplace are discussed, along with how they have been or may be addressed. The stakeholder input process for guiding research and development needs via the Natural Gas Vehicle Technology Forum (NGVTF) to the U.S. Department of Energy and the California Energy Commission is reviewed. Current high-level natural gas engine development gap areas are highlighted, including efficiency, emissions, and the certification process.

  12. 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.

  13. 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.

  14. Natural product discovery: past, present, and future.

    Science.gov (United States)

    Katz, Leonard; Baltz, Richard H

    2016-03-01

    Microorganisms have provided abundant sources of natural products which have been developed as commercial products for human medicine, animal health, and plant crop protection. In the early years of natural product discovery from microorganisms (The Golden Age), new antibiotics were found with relative ease from low-throughput fermentation and whole cell screening methods. Later, molecular genetic and medicinal chemistry approaches were applied to modify and improve the activities of important chemical scaffolds, and more sophisticated screening methods were directed at target disease states. In the 1990s, the pharmaceutical industry moved to high-throughput screening of synthetic chemical libraries against many potential therapeutic targets, including new targets identified from the human genome sequencing project, largely to the exclusion of natural products, and discovery rates dropped dramatically. Nonetheless, natural products continued to provide key scaffolds for drug development. In the current millennium, it was discovered from genome sequencing that microbes with large genomes have the capacity to produce about ten times as many secondary metabolites as was previously recognized. Indeed, the most gifted actinomycetes have the capacity to produce around 30-50 secondary metabolites. With the precipitous drop in cost for genome sequencing, it is now feasible to sequence thousands of actinomycete genomes to identify the "biosynthetic dark matter" as sources for the discovery of new and novel secondary metabolites. Advances in bioinformatics, mass spectrometry, proteomics, transcriptomics, metabolomics and gene expression are driving the new field of microbial genome mining for applications in natural product discovery and development.

  15. Present and future of natural gas

    Energy Technology Data Exchange (ETDEWEB)

    Wionczek, M.S.; Serrato, M.

    Analyses of world market behavior focused on crude oil until 1980, and paid little attention to future natural gas developments. The authors, after reviewing significant changes in the gas industry, explain the implications of the changes and point out possible trends for the rest of this decade. They assume a maturing international industry. Their analysis suggests an increasing rate of natural gas development because reserves are proving to be larger than expected, which will make gas a viable competitor of crude oil for direct burning and feedstocks. As world markets and industry infrastructure expand, wasteful flaring will diminish. This will especially benefit the less-developed oil-producing countries. 20 references. (DCK)

  16. Teaching Rousseau: Natural Man and Present Existence.

    Science.gov (United States)

    Rice, Daryl H.

    1989-01-01

    Offers an interpretation of Jean-Jacques Rousseau's "Discourse on the Origin and Foundations of Inequality" and provides examples of classroom exercises designed to make Rousseau's ideas and writings accessible to undergraduates. Stresses Rousseau's philosophy on natural man, language, ethics, and society. Includes interpretive…

  17. Teaching Rousseau: Natural Man and Present Existence.

    Science.gov (United States)

    Rice, Daryl H.

    1989-01-01

    Offers an interpretation of Jean-Jacques Rousseau's "Discourse on the Origin and Foundations of Inequality" and provides examples of classroom exercises designed to make Rousseau's ideas and writings accessible to undergraduates. Stresses Rousseau's philosophy on natural man, language, ethics, and society. Includes interpretive references to…

  18. 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.

  19. Natural sound archives: past, present and future

    Directory of Open Access Journals (Sweden)

    Ranft Richard

    2004-01-01

    Full Text Available Recordings of wild animals were first made in the Palearctic in 1900, in the Nearctic in 1929, in Antarctica in 1934, in Asia in 1937, and in the Neotropics in the 1940s. However, systematic collecting did not begin until the 1950s. Collections of animal sound recordings serve many uses in education, entertainment, science and nature conservation. In recent years, technological developments have transformed the ways in which sounds can be sampled, stored and accessed. Now the largest collections between them hold altogether around 0.5 million recordings with their associated data. The functioning of a major archive will be described with reference to the British Library Sound Archive. Preserving large collections for the long term is a primary concern in the digital age. While digitization and digital preservation has many advantages over analogue methods, the rate of technology change and lack of standardization are a serious problem for theworld's major audio archives. Another challenge is to make collections more easily and widely accessible via electronic networks. On-line catalogues and access to the actual sounds via the internet are already available for some collections. Case studies describing the establishment and functioning of sound libraries inMexico, Colombia and Brazil are given in individually authored sections in an Appendix.

  20. Natural sound archives: past, present and future.

    Science.gov (United States)

    Ranft, Richard

    2004-06-01

    Recordings of wild animals were first made in the Palearctic in 1900, in the Nearctic in 1929, in Antarctica in 1934, in Asia in 1937, and in the Neotropics in the 1940s. However, systematic collecting did not begin until the 1950s. Collections of animal sound recordings serve many uses in education, entertainment, science and nature conservation. In recent years, technological developments have transformed the ways in which sounds can be sampled, stored and accessed. Now the largest collections between them hold altogether around 0.5 million recordings with their associated data. The functioning of a major archive will be described with reference to the British Library Sound Archive. Preserving large collections for the long term is a primary concern in the digital age. While digitization and digital preservation has many advantages over analogue methods, the rate of technology change and lack of standardization are a serious problem for the world's major audio archives. Another challenge is to make collections more easily and widely accessible via electronic networks. On-line catalogues and access to the actual sounds via the internet are already available for some collections. Case studies describing the establishment and functioning of sound libraries in Mexico, Colombia and Brazil are given in individually authored sections in an Appendix.

  1. 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

  2. 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

  3. 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.

  4. 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.

  5. 天然药物活性成分与溶菌酶相互作用的研究进展%Advance of studies on interaction between active components of natural medicines and lysozymes

    Institute of Scientific and Technical Information of China (English)

    陈晨; 张洪峰; 王乐; 黄芸; 魏亚超; 郭金明; 郭莹

    2012-01-01

    溶菌酶是一种广泛存在于生物体内的小分子碱性蛋白,具有抗菌消炎、抗病毒、增强免疫力等多种药理作用.能够和许多外源和内源性物质结合,运载多种药物.该文综述了不同种类的天然药物活性成分与溶菌酶的相互作用,对于全面认识天然药物的药理机制,了解药物在生物体内的转运和代谢过程以及优化药物分子结构、提高天然药物的生物利用率和生物效应等都具有重要的意义.%Lysozyme (LYSO) , as an alkalescent protein micromolecule in living organisms, exhibits important pharmacological actions such as antibiosis, anti-inflammatory, antivirus and enhancing immunity. LYSO can combine with many exogenous and endogenous substances and carry many drugs. This essay summarizes interaction between different kincis of active components of natural medicines and lysozymes, which is significant to comprehensively understand pharmacological mechanism of natural drugs and their transfer and metabolic process in organisms, optimize molecule structures of drugs and increase bioavailability and biological effects of natural drugs.

  6. 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.

  7. 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.

  8. Relaxation with Immersive Natural Scenes Presented Using Virtual Reality.

    Science.gov (United States)

    Anderson, Allison P; Mayer, Michael D; Fellows, Abigail M; Cowan, Devin R; Hegel, Mark T; Buckey, Jay C

    2017-06-01

    Virtual reality (VR) can provide exposure to nature for those living in isolated confined environments. We evaluated VR-presented natural settings for reducing stress and improving mood. There were 18 participants (9 men, 9 women), ages 32 ± 12 yr, who viewed three 15-min 360° scenes (an indoor control, rural Ireland, and remote beaches). Subjects were mentally stressed with arithmetic before scenes. Electrodermal activity (EDA) and heart rate variability measured psycho-physiological arousal. The Positive and Negative Affect Schedule and the 15-question Modified Reality Judgment and Presence Questionnaire (MRJPQ) measured mood and scene quality. Reductions in EDA from baseline were greater at the end of the natural scenes compared to the control scene (-0.59, -0.52, and 0.32 μS, respectively). The natural scenes reduced negative affect from baseline ( 1.2 and 1.1 points), but the control scene did not ( 0.4 points). MRJPQ scores for the control scene were lower than both natural scenes (4.9, 6.7, and 6.5 points, respectively). Within the two natural scenes, the preferred scene reduced negative affect ( 2.4 points) more than the second choice scene ( 1.8 points) and scored higher on the MRJPQ (6.8 vs. 6.4 points). Natural scene VR provided relaxation both objectively and subjectively, and scene preference had a significant effect on mood and perception of scene quality. VR may enable relaxation for people living in isolated confined environments, particularly when matched to personal preferences.Anderson AP, Mayer MD, Fellows AM, Cowan DR, Hegel MT, Buckey JC. Relaxation with immersive natural scenes presented using virtual reality. Aerosp Med Hum Perform. 2017; 88(6):520526.

  9. Presentation rate in comprehension of natural and synthesized speech.

    Science.gov (United States)

    Reynolds, M E; Givens, J

    2001-06-01

    This study examined the effect of four presentation rates (approximately 130, 150, 170, and 190 words per minute) on the comprehension of natural and synthesized speech by having 96 subjects [1 man, 95 women ranging in age from 18 to 40 years (M=21.0)] perform a sentence-verification task. Analysis showed that, while their response latencies were significantly faster to natural than to synthesized speech, presentation rate did not have a significant effect on response latencies when sentences were presented at rates within the average speaking range (approximately 130 to 190 words per minute). Implications these findings may have for the use of synthesized speech in human factors applications are discussed.

  10. 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.

  11. 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

  12. Possible Pathways for Increasing Natural Gas Use for Transportation (Presentation)

    Energy Technology Data Exchange (ETDEWEB)

    Zigler, B.

    2014-10-01

    A collaborative partnership of DOE National Laboratories is working with DOE to identify critical RD&D needs to significantly increase the speed and breadth of NG uptake into the transportation sector. Drivers for increased utilization of natural gas for transportation are discussed. Key needs in research, development, and deployment are proposed, as well as possible pathways to address those needs. This presentation is intended to serve as a catalyst to solicit input from stakeholders regarding what technical areas they deem the most important.

  13. 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.

  14. Present and future of allogeneic natural killer cell therapy

    Directory of Open Access Journals (Sweden)

    Okjae eLim

    2015-06-01

    Full Text Available Natural killer (NK cells are innate lymphocytes that are capable of eliminating tumor cells and are therefore used for cancer therapy. Although many early investigators used autologous NK cells, including lymphokine-activated killer cells, the clinical efficacies were not satisfactory. Meanwhile, human leukocyte antigen (HLA-haploidentical hematopoietic stem cell transplantation revealed the anti-tumor effect of allogeneic NK cells, and HLA-haploidentical, killer cell immunoglobulin-like receptor (KIR ligand-mismatched allogeneic NK cells are currently used for many protocols requiring NK cells. Moreover, allogeneic NK cells from non-HLA-related healthy donors have been recently used in cancer therapy. The use of allogeneic NK cells from non-HLA-related healthy donors allows the selection of donor NK cells with higher flexibility and to prepare expanded, cryopreserved NK cells for instant administration without delay for ex vivo expansion. In cancer therapy with allogeneic NK cells, optimal matching of donors and recipients is important to maximize the efficacy of the therapy. In this review, we summarize the present state of allogeneic NK cell therapy and its future directions.

  15. 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.

  16. 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.

  17. Control of Avian Coccidiosis: Future and Present Natural Alternatives

    Directory of Open Access Journals (Sweden)

    Rosa Estela Quiroz-Castañeda

    2015-01-01

    Full Text Available Numerous efforts to date have been implemented in the control of avian coccidiosis caused by the Eimeria parasite. Since the appearance of anticoccidial chemical compounds, the search for new alternatives continues. Today, no product is available to cope with the disease; however, the number of products commercially available is constantly increasing. In this review, we focus on natural products and their anticoccidial activity. This group comprises fatty acids, antioxidants, fungal and herbal extracts, and immune response modulators with proven anticoccidial activity, many of which exist as dietary supplements. Additionally, we offer an overview of the poultry industry and the economic cost of coccidiosis as well as the classical strategies used to control the disease.

  18. Excess entropy in natural language: present state and perspectives

    CERN Document Server

    Dęowski, Łukasz

    2011-01-01

    We review recent progress in understanding the meaning of mutual information in natural language. Let us define words in a text as strings that occur sufficiently often. In a few previous papers, we have shown that a power-law distribution for so defined words (a.k.a. Zipf's or Herdan's law) is obeyed if there is a similar power-law growth of (algorithmic) mutual information between adjacent portions of texts of increasing length. Moreover, the power-law growth of information holds if texts describe a complicated infinite (algorithmically) random object in a highly repetitive way, according to an analogous power-law distribution. The described object may be immutable (like a mathematical or physical constant) or may evolve slowly in time (like cultural heritage). Here we reflect on the respective mathematical results in a less technical way. We also discuss feasibility of deciding to what extent these results apply to the actual human communication.

  19. Control of avian coccidiosis: future and present natural alternatives.

    Science.gov (United States)

    Quiroz-Castañeda, Rosa Estela; Dantán-González, Edgar

    2015-01-01

    Numerous efforts to date have been implemented in the control of avian coccidiosis caused by the Eimeria parasite. Since the appearance of anticoccidial chemical compounds, the search for new alternatives continues. Today, no product is available to cope with the disease; however, the number of products commercially available is constantly increasing. In this review, we focus on natural products and their anticoccidial activity. This group comprises fatty acids, antioxidants, fungal and herbal extracts, and immune response modulators with proven anticoccidial activity, many of which exist as dietary supplements. Additionally, we offer an overview of the poultry industry and the economic cost of coccidiosis as well as the classical strategies used to control the disease.

  20. 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...

  1. 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

  2. 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.

  3. Pediatric paradoxical vocal-fold motion: presentation and natural history.

    Science.gov (United States)

    Maturo, Stephen; Hill, Courtney; Bunting, Glenn; Baliff, Cathy; Ramakrishna, Jyoti; Scirica, Christina; Fracchia, Shannon; Donovan, Abigail; Hartnick, Christopher

    2011-12-01

    To describe (1) a cohort of children with paradoxical vocal-fold motion (PVFM) who were referred to a multidisciplinary airway center and (2) the outcomes of various treatment modalities including speech therapy, gastroesophageal reflux disease treatment, and psychiatric treatment. This was a case series with chart review of children younger than 18 years with PVFM evaluated at a tertiary care pediatric airway center over a 36-month period. Fifty-nine children with PVFM were evaluated. The cohort had a mean age of 13.64 years (range: 8-18 years) and a female-to-male ratio of 3:1. Speech therapy as an initial treatment resulted in a 63% (24 of 38) success rate after an average of 3.7 treatment sessions. Speech therapy was a more successful treatment than antireflux therapy (P = .001). Ten percent (6 of 59) of the children presented with a known psychiatric diagnosis, and 30% (18 of 59) of children in the cohort were ultimately diagnosed with a psychiatric condition. Children with inspiratory stridor at rest had a lower initial success rate with speech therapy (56%), a higher rate of underlying psychiatric disorders (75%), and a high rate of success after psychiatric treatment (100%) that required, on average, 3 sessions over a 2-month period. To our knowledge, this is the largest study to date on pediatric PVFM. The majority of children with PVFM improve with speech therapy. Children with PVFM at rest may be better treated with psychiatric therapy than speech therapy. Furthermore, children who present with symptoms at rest may have a higher likelihood of underlying psychiatric disease.

  4. 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.

  5. 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.

  6. 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

  7. 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....

  8. 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

  9. 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.

  10. 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.

  11. 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

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. Shift in aggregation, ROS generation, antioxidative defense, lysozyme and acetylcholinesterase activities in the cells of an Indian freshwater sponge exposed to washing soda (sodium carbonate).

    Science.gov (United States)

    Mukherjee, Soumalya; Ray, Mitali; Ray, Sajal

    2016-09-01

    Washing soda, chemically identified as anhydrous sodium carbonate, is a popular cleaning agent among the rural and urban populations of India which often contaminates the freshwater ponds and lakes, the natural habitat of sponge Eunapius carteri. Present investigation deals with estimation of cellular aggregation, generation of ROS and activities of antioxidant enzymes, lysozyme and acetylcholinesterase in the cells of E. carteri under the environmentally realistic concentrations of washing soda. Prolonged treatment of washing soda inhibited the degree of cellular aggregation. Experimental exposure of 8 and 16mg/l of sodium carbonate for 48h elevated the physiological level of reactive oxygen species (ROS) generation in the agranulocytes, semigranulocytes and granulocytes of E. carteri, whereas, treatment of 192h inhibited the ROS generation in three cellular morphotypes. Activities of superoxide dismutase, catalase and glutathione-S-transferase were recorded to be inhibited under prolonged exposure of washing soda. Washing soda mediated inhibition of ROS generation and depletion in the activities of antioxidant enzymes were indicative to an undesirable shift in cytotoxic status and antioxidative defense in E. carteri. Inhibition in the activity of lysozyme under the treatment of sodium carbonate was suggestive to a severe impairment of the innate immunological efficiency of E. carteri distributed in the washing soda contaminated habitat. Washing soda mediated inhibition in the activity of acetylcholinesterase indicated its neurotoxicity in E. carteri. Washing soda, a reported environmental contaminant, affected adversely the immunophysiological status of E. carteri with reference to cellular aggregation, oxidative stress, antioxidative defense, lysozyme and acetylcholinesterase activity.

  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. 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...

  5. 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

  6. 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...

  7. 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.

  8. 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.

  9. NATURE CONSERVATION MOVEMENT IN THE WORLD: ITS HISTORICAL DEVELOPMENT AND PRESENT SITUATION

    Directory of Open Access Journals (Sweden)

    Oğuz Kurdoğlu

    2007-04-01

    Full Text Available Although nature conservation is a well recognized topic at present, it is not a new phenomenon. Throughout history, there are numerous examples of efforts made by governments, rulers, or individual land owners to protect certain land areas that possessed unique natural values. While many of these areas were actually isolated as game preserves for hunting, they were also designed to conserve wildlife. The establishment of Yellowstone National Park in 1972 marks the modern concept of a national park as it was designed on a very large protected natural area. Presently, one of the most efficient ways for nature protection is “area conservation approach” that many organizations have been developing various systems and categories about. Unfortunately, in spite of such improvements and the extension of the protected area network, many of these areas are not properly protected and/or managed in some countries. This study summarizes the historical evolution of nature conservation systems and strategies in the world with the related international legislative aspects as well. As it stated in this paper, USA and Europa have a well known history on nature conservation and show great concern in respect to participating to the international convention and arrangements.

  10. The benefits of mystery in nature on attention: assessing the impacts of presentation duration.

    Science.gov (United States)

    Szolosi, Andrew M; Watson, Jason M; Ruddell, Edward J

    2014-01-01

    Although research has provided prodigious evidence in support of the cognitive benefits that natural settings have over urban settings, all nature is not equal. Within nature, natural settings that contain mystery are often among the most preferred nature scenes. With the prospect of acquiring new information, scenes of this type could more effectively elicit a person's sense of fascination, enabling that person to rest the more effortful forms of attention. The present study examined the direct cognitive benefits that mystery in nature has on attention. Settings of this sort presumably evoke a form of attention that is undemanding or effortless. In order to investigate that notion, participants (n = 144) completed a Recognition Memory Task (RMT) that evaluated recognition performance based on the presence of mystery and presentation duration (300 ms, 1 s, 5 s, and 10 s). Results revealed that with additional viewing time, images perceived high in mystery achieved greater improvements in recognition performance when compared to those images perceived low in mystery. Tests for mediation showed that the effect mystery had on recognition performance occurred through perceptions of fascination. Implications of these and other findings are discussed in the context of Attention Restoration Theory.

  11. The benefits of mystery in nature on attention: Assessing the impacts of presentation duration

    Directory of Open Access Journals (Sweden)

    Andrew Martin Szolosi

    2014-11-01

    Full Text Available Although research has provided prodigious evidence in support of the cognitive benefits that natural settings have over urban settings, all nature is not equal. Within nature, natural settings that contain mystery are often among the most preferred nature scenes. With the prospect of acquiring new information, scenes of this type could more effectively elicit a person’s sense of fascination, enabling that person to rest the more effortful forms of attention. The present study examined the direct cognitive benefits that mystery in nature has on attention. Settings of this sort presumably evoke a form of attention that is undemanding or effortless. In order to investigate that notion, participants (n=144 completed a Recognition Memory Task (RMT that evaluated recognition performance based on the presence of mystery and presentation duration (300 ms, 1 sec, 5 sec, and 10 sec. Results revealed that with additional viewing time, images perceived high in mystery achieved greater improvements in recognition performance when compared to those images perceived low in mystery. Tests for mediation showed that the effect mystery had on recognition performance occurred through perceptions of fascination. Implications of these and other findings are discussed in the context of Attention Restoration Theory.

  12. 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.

  13. 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.

  14. 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).

  15. PRESENTATIONAL TRAINING LECTURES ON NATURAL-SCIENCE DISCIPLINES: PRACTICE AND THEORY

    Directory of Open Access Journals (Sweden)

    Elena P. Bogomolova

    2014-01-01

    Full Text Available This paper discusses the feasibility of delivering streaming lectures on natural-science disciplines with computer presentations. Typical students’ comments on those are observed. There are analyzed the strengths and weaknesses of this form of delivery of lecture material for students of full-time training. 

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. Quantitative Probing of Cu(2+) Ions Naturally Present in Single Living Cells.

    Science.gov (United States)

    Lee, Junho; Lee, Hwa-Rim; Pyo, Jaeyeon; Jung, Youngseob; Seo, Ji-Young; Ryu, Hye Guk; Kim, Kyong-Tai; Je, Jung Ho

    2016-06-01

    Quantitative probing of Cu(2+) ions naturally present in single living cells is realized by developing a quantum-dot-embedded nanowire-waveguide probe. The intracellular Cu(2+) ion concentration is quantified by direct monitoring of photoluminescence quenching during the insertion of the nanowire in a living neuron. The measured intracellular Cu(2+) ion concentration is 3.34 ± 1.04 × 10(-6) m (mean ± s.e.m.) in single hippocampal neurons.

  5. Bibliography of reports, papers, and presentations on naturally occurring radioactive material (NORM) in petroleum industry wastes

    Energy Technology Data Exchange (ETDEWEB)

    Smith, K.P.; Wilkey, M.L.; Hames, R.D.

    1997-07-01

    This bibliography was created to support projects conducted by Argonne National Laboratory (ANL) addressing issues related to naturally occurring radioactive material (NORM) in petroleum industry wastes. The bibliography provides citations for many of the available published reports, papers, articles, and presentations on petroleum industry NORM. In the past few years, the rapid expansion of NORM treatment and disposal technologies, the efforts to characterize NORM wastes and their associated potential risks, and the promulgation of state-level NORM regulatory programs have been well-documented in project reports and in papers presented at technical conferences and symposia. There are 221 citations.

  6. Protein dynamics by neutron scattering: The protein dynamical transition and the fragile-to-strong dynamical crossover in hydrated lysozyme

    Energy Technology Data Exchange (ETDEWEB)

    Magazù, Salvatore; Migliardo, Federica [Dipartimento di Fisica, Università di Messina, C. da Papardo n° 31, P.O. Box 55, Vill. S. Agata, 98166 Messina (Italy); Benedetto, Antonio, E-mail: antonio.benedetto@ucd.ie [School of Physics, University College Dublin-UCD, Belfield Campus, Dublin 2 (Ireland); School of Medical Sciences, Sydney Medical School, The University of Sydney, Anderson Stuart Building F13, Sydney, NSW 2006 (Australia); Vertessy, Beata [Institute of Enzymology, Hungarian Academy of Sciences, Karolina 29, H-1113 Budapest (Hungary)

    2013-10-16

    Highlights: • The role played by the instrumental energy resolution in neutron scattering is presented. • The effect of natural bioprotectants on protein dynamics is shown. • A connection between the protein dynamical transition and the fragile-to-strong dynamical crossover is formulated. - Abstract: In this work Elastic Incoherent Neutron Scattering (EINS) results on lysozyme water mixtures in absence and in presence of bioprotectant systems are presented. The EINS data have been collected by using the IN13 and the IN10 spectrometers at the Institut Laue-Langevin (ILL, Grenoble, France) allowing to evaluate the temperature behaviour of the mean square displacement and of the relaxation time for the investigated systems. The obtained experimental findings together with theoretical calculations allow to put into evidence the role played by the spectrometer resolution and to clarify the connexion between the registered protein dynamical transition, the system relaxation time, and the instrumental energy resolution.

  7. Presentation

    Directory of Open Access Journals (Sweden)

    Paulo Henrique Freire Vieira

    2013-12-01

    Full Text Available This dossier focuses on one of the essential debate topics today about the territorial dimension of the new development strategies concerned with the worsening of the global socioecological crisis, that is: the challenges related to the activation and integration in networks of localized agri-food systems. For its composition, some contributions presented and debated during the VI International Conference on Localized Agri-food System - The LAFS facing the opportunities and challenges of the new global context have been gathered. The event took place in the city of Florianópolis, from May 21th to 25th of 2013. The event was promoted by the Federal University of Santa Catarina (UFSC and by the Center for the International Cooperation on Agricultural Research for Development (CIRAD. Besides UFSC and CIRAD, EPAGRI, State University of Santa Catarina (UDESC, as well as research institutes and universities from other states (UFMG, IEA/SP, UFS, UFRGS and Mexican and Argentinian partners from the RED SIAL Latino Americana also participated in the organization of lectures, discussion tables and workshops.

  8. Presentation

    Directory of Open Access Journals (Sweden)

    Eduardo Vicente

    2013-06-01

    Full Text Available In the present edition of Significação – Scientific Journal for Audiovisual Culture and in the others to follow something new is brought: the presence of thematic dossiers which are to be organized by invited scholars. The appointed subject for the very first one of them was Radio and the invited scholar, Eduardo Vicente, professor at the Graduate Course in Audiovisual and at the Postgraduate Program in Audiovisual Media and Processes of the School of Communication and Arts of the University of São Paulo (ECA-USP. Entitled Radio Beyond Borders the dossier gathers six articles and the intention of reuniting works on the perspectives of usage of such media as much as on the new possibilities of aesthetical experimenting being build up for it, especially considering the new digital technologies and technological convergences. It also intends to present works with original theoretical approach and original reflections able to reset the way we look at what is today already a centennial media. Having broadened the meaning of “beyond borders”, four foreign authors were invited to join the dossier. This is the first time they are being published in this country and so, in all cases, the articles where either written or translated into Portuguese.The dossier begins with “Radio is dead…Long live to the sound”, which is the transcription of a thought provoking lecture given by Armand Balsebre (Autonomous University of Barcelona – one of the most influential authors in the world on the Radio study field. It addresses the challenges such media is to face so that it can become “a new sound media, in the context of a new soundscape or sound-sphere, for the new listeners”. Andrew Dubber (Birmingham City University regarding the challenges posed by a Digital Era argues for a theoretical approach in radio studies which can consider a Media Ecology. The author understands the form and discourse of radio as a negotiation of affordances and

  9. Presentation

    Directory of Open Access Journals (Sweden)

    Helmut Renders

    2008-10-01

    Full Text Available We present to our esteemed readers the second edition of our journal for 2008. We have chosen the theme “The life and work of Prof. Dr. Jürgen Moltmann” as its special emphasis. It is our way to pay homage to J. Moltmann in the year the Universidade Metodista de São Paulo awards him an honorary Doctor Honoris Causa degree. Sincethe seventies, Moltmann and Latin America have been in dialog. In his emblematic work “A Theology of Liberation”, Gustavo Gutiérrez, the Catholic, discussed with Moltmann, the Reformed, the relationship between eschatology and history (GUTIÉRREZ, Gustavo.Teologia da Libertação. 5ª edição. Petrópolis, RJ: Vozes, 1985, p. 27, 137-139. A dialog held in the premises of IMS, which nowadays is called UMESP, has produced the little book “Passion for life” (MOLTMANN, Jürgen. Paixão pela vida. São Paulo, SP: ASTE - Associaçãode Seminários Teológicos Evangélicos, 1978.In the following years, the wide theological work of J. Moltmann went all the way from debates to congresses and has conquered the classrooms. Most probably, J. Moltmann is nowadays the most widely read European author in Brazilian theological seminaries. Thisrecognition can only be held in unison and the wide response to our request for articles confirms the huge repercussion that Moltmann’s work has been having up to today in Brazil. The ecumenical theologian J. Moltmann is ecumenically read. We believe that thisway we may be better equipped to answer to anyone who asks us for the reason there is hope in us. We have organized the articles on J. Moltmann’s theology according to the original publication date of the books dealt with in each essay. We also communicate that some articles which were originally requested for this edition of the journal will be published in the journal Estudos de Regilião in May 2009.As it is usual with the journal Caminhando, we have, besides this thematic emphasis, yet other contributions in the areas of

  10. Asymptomatic cattle naturally infected with Mycobacterium bovis present exacerbated tissue pathology and bacterial dissemination.

    Directory of Open Access Journals (Sweden)

    Álvaro Menin

    Full Text Available Rational discovery of novel immunodiagnostic and vaccine candidate antigens to control bovine tuberculosis (bTB requires knowledge of disease immunopathogenesis. However, there remains a paucity of information on the Mycobacterium bovis-host immune interactions during the natural infection. Analysis of 247 naturally PPD+ M. bovis-infected cattle revealed that 92% (n = 228 of these animals were found to display no clinical signs, but presented severe as well as disseminated bTB-lesions at post-mortem examination. Moreover, dissemination of bTB-lesions positively correlated with both pathology severity score (Spearman r = 0.48; p<0.0001 and viable tissue bacterial loads (Spearman r = 0.58; p = 0.0001. Additionally, granuloma encapsulation negatively correlated with M. bovis growth as well as pathology severity, suggesting that encapsulation is an effective mechanism to control bacterial proliferation during natural infection. Moreover, multinucleated giant cell numbers were found to negatively correlate with bacterial counts (Spearman r = 0.25; p = 0.03 in lung granulomas. In contrast, neutrophil numbers in the granuloma were associated with increased M. bovis proliferation (Spearman r = 0.27; p = 0.021. Together, our findings suggest that encapsulation and multinucleated giant cells control M. bovis viability, whereas neutrophils may serve as a cellular biomarker of bacterial proliferation during natural infection. These data integrate host granuloma responses with mycobacterial dissemination and could provide useful immunopathological-based biomarkers of disease severity in natural infection with M. bovis, an important cattle pathogen.

  11. Presentation

    Directory of Open Access Journals (Sweden)

    Nicanor Lopes

    2010-11-01

    Full Text Available The Journal Caminhando debuts with a new editorial format: eachmagazine will have a Dossier.In 2010 Christianity celebrated the centenary of Edinburgh. TheWorld Missionary Conference in Edinburgh in 1910 is regarded by manyas missiological watershed in the missionary and ecumenical movement.So the Faculty of Theology of the Methodist Church (FATEO decidedto organize a Wesleyan Week discussing the issue of mission. For anevent of this magnitude FATEO invited the Rev. Dr. Wesley Ariarajah,Methodist pastor and teacher of Sri Lanka with extensive experience inpastoral ministry in local churches and professor of History of Religionsand the New Testament at the Theological College of Lanka, maintainedby the Protestant Churches in Sri Lanka. In 1981 he was invited to jointhe World Council of Churches, where he presided for over ten years theCouncil of Interreligious Dialogue. From 1992 he served as Deputy GeneralSecretary of the WCC.The following texts are not the speeches of the Rev. Dr. WesleyAriarajah, for they will be published separately. Nevertheless, the journaldialogs with the celebrations of the centenary of Edinburgh, parting formthe intriguing theme: "Mission in the 21st century in Brazil". After all, howis it that mission takes place among us in personal, church, and communityactivities?Within the Dossier, as common to the journal, the textos are organizedas follows: Bible, Theology / History and Pastoral Care. Other items thatdo not fit within the Dossier, but, do articulate mission, can be found inthe section Declarations and Documents and Book Reviews.The authors of the Dossier have important considerations in buildinga contemporary missiological concept considering Brazilian reality.Anderson de Oliveira, in the Bible-Section, presents a significantexegeses of Matthew 26.6-13. What does it mean when Jesus is quotedwith the words: "For the poor always ye have with you, but me ye havenot always." Is this declaration challenging the gospels

  12. 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.

  13. 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.

  14. Gender differences in responses to cues presented in the natural environment of cigarette smokers.

    Science.gov (United States)

    Wray, Jennifer M; Gray, Kevin M; McClure, Erin A; Carpenter, Matthew J; Tiffany, Stephen T; Saladin, Michael E

    2015-04-01

    Although the evidence is mixed, female smokers appear to have more difficulty quitting smoking than male smokers. Craving, stress, and negative affect have been hypothesized as potential factors underlying gender differences in quit rates. In the current study, the cue-reactivity paradigm was used to assess craving, stress, and negative affect in response to cues presented in the natural environment of cigarette smokers using ecological momentary assessment. Seventy-six daily smokers (42% female) responded to photographs (smoking, stress, and neutral) presented 4 times per day on an iPhone over the course of 2 weeks. Both smoking and stress cues elicited stronger cigarette craving and stress responses compared to neutral cues. Compared with males, females reported higher levels of post-stress cue craving, stress, and negative affect, but response to smoking cues did not differ by gender. Findings from this project were largely consistent with results from laboratory-based research and extend previous work by measuring response to cues in the natural environment of cigarette smokers. This study extends previous cue reactivity ecological momentary assessment research by using a new platform and by measuring response to stress cues outside of the laboratory. Findings from this project highlight the importance of addressing coping in response to stress cues in clinical settings, especially when working with female smokers. © The Author 2015. Published by Oxford University Press on behalf of the Society for Research on Nicotine and Tobacco. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  15. 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.

  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. 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.

  18. 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

  19. The nature and dimensions of achievement goals: mastery, evaluation, competition, and self-presentation goals.

    Science.gov (United States)

    Lemos, Marina S; Gonçalves, Teresa; Lens, Willy; Rodrigues, Luís P

    2014-01-01

    The present study aimed to clarify the nature and dimensions of achievement goals and to examine structural differences in students' goals across school levels. Participants were 134 students from 5th and 6th grades, and 423 students from 7th to 9th grades. A variety of achievement goals were assessed, including mastery goals and several performance-related goals representing three main dimensions: competition, self-presentation, and valence. Two alternative models were tested, using confirmatory factor analysis. For middle-school students a three factor model with presentation, competition, and simple evaluation/mastery goals, was found χ²(132, N = 134) = 160.9, p goals, and (b) simple evaluation goals, which encompass neither self-presentation nor competition, and are closely linked to mastery goals. Moreover, significant differences were found in the relative importance attached by students to the different types of goals (p < .001 for all comparisons), both at middle-school F(2, 266) = 220.98; p < .001; η2 = .624) and at junior-high school F(2, 820) = 464.4; p < .001; η2 = .531.

  20. 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.

  1. 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.

  2. Present status of understanding on the G6PD deficiency and natural selection

    Directory of Open Access Journals (Sweden)

    Tripathy V

    2007-01-01

    Full Text Available G6PD deficiency is a common hemolytic genetic disorder, particularly in the areas endemic to malaria. Individuals are generally asymptomatic and hemolytic anemia occurs when some anti-malarial drugs or other oxidizing chemicals are administered. It has been proposed that G6PD deficiency provides protection against malaria. Maintaining of G6PD deficient alleles at polymorphic proportions is complicated because of the X-linked nature of G6PD deficiency. A comprehensive review of the literature on the hypothesis of malarial protection and the nature of the selection is being presented. Most of the epidemiological, in vitro and in vivo studies report selection for G6PD deficiency. Analysis of the G6PD gene also reveals that G6PD-deficient alleles show some signatures of selection. However, the question of how this polymorphism is being maintained remains unresolved because the selection/fitness coefficients for the different genotypes in the two sexes have not been established. Prevalence of G6PD deficiency in Indian caste and tribal populations and the different variants reported has also been reviewed.

  3. Neural Correlates of Word Recognition: A Systematic Comparison of Natural Reading and Rapid Serial Visual Presentation.

    Science.gov (United States)

    Kornrumpf, Benthe; Niefind, Florian; Sommer, Werner; Dimigen, Olaf

    2016-09-01

    Neural correlates of word recognition are commonly studied with (rapid) serial visual presentation (RSVP), a condition that eliminates three fundamental properties of natural reading: parafoveal preprocessing, saccade execution, and the fast changes in attentional processing load occurring from fixation to fixation. We combined eye-tracking and EEG to systematically investigate the impact of all three factors on brain-electric activity during reading. Participants read lists of words either actively with eye movements (eliciting fixation-related potentials) or maintained fixation while the text moved passively through foveal vision at a matched pace (RSVP-with-flankers paradigm, eliciting ERPs). The preview of the upcoming word was manipulated by changing the number of parafoveally visible letters. Processing load was varied by presenting words of varying lexical frequency. We found that all three factors have strong interactive effects on the brain's responses to words: Once a word was fixated, occipitotemporal N1 amplitude decreased monotonically with the amount of parafoveal information available during the preceding fixation; hence, the N1 component was markedly attenuated under reading conditions with preview. Importantly, this preview effect was substantially larger during active reading (with saccades) than during passive RSVP with flankers, suggesting that the execution of eye movements facilitates word recognition by increasing parafoveal preprocessing. Lastly, we found that the N1 component elicited by a word also reflects the lexical processing load imposed by the previously inspected word. Together, these results demonstrate that, under more natural conditions, words are recognized in a spatiotemporally distributed and interdependent manner across multiple eye fixations, a process that is mediated by active motor behavior.

  4. 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.

  5. Adsorption of natural surfactants present in sea waters at surfaces of minerals: contact angle measurements

    Directory of Open Access Journals (Sweden)

    Katarzyna Boniewicz-Szmyt

    2009-09-01

    importance in numerous technological processes including froth flotation, demulgation, anti-foaming procedures and the coal industries. It is believed that the approach presented here and the examples of its application to common sea water/solid mineral systems could be successfully adapted to optimise several surfactant-mediated adsorption processes (see below of practical value in natural water ecology.

  6. 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

  7. [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.

  8. 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.

  9. 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.

  10. Present Situation and Forecast of Natural Gas Exploitation and Utilization in China

    Institute of Scientific and Technical Information of China (English)

    Shi Xunzhi

    1995-01-01

    @@ China is a country with rich oil and gas resources and also a big country of energy resource consumption. With the development of economy in China,the growth of exploitation and utilization of oil and natural gas resources will be continued. Especially, there will be a more eager to demand natural gas and a higher speed of gas exploitation than that of oil.

  11. Oxidized epigallocatechin gallate inhibited lysozyme fibrillation more strongly than the native form

    Directory of Open Access Journals (Sweden)

    Ting-Ting An

    2017-04-01

    Full Text Available Epigallocatechin gallate (EGCG, the most abundant flavanoid in green tea, is currently being evaluated in the clinic due to its benefits in the treatment of amyloid disorders. Its anti-amyloidogenic effect has been attributed to direct interaction of the intact molecule with misfolded polypeptides. In addition, antioxidant activity is also involved in the anti-amyloidogenic role. The detailed molecular mechanism is still unclear and requires further investigation. In the present study, the kinetics of EGCG oxidation and the anti-amyloidogenic effect of the resultant oxidation substances have been examined. The results indicate that EGCG degrades in a medium at pH 8.0 with a half-life less than 2 h. By utilizing lysozyme as an in vitro model, the oxidized EGCG demonstrates a more potent anti-amyloidogenic capacity than the intact molecule, as shown by ThT and ANS fluorescence, TEM determination, and hemolytic assay. The oxidized EGCG also has a stronger disruptive effect on preformed fibrils than the native form. Ascorbic acid eliminates the disruptive role of native EGCG on the fibrils, suggesting that oxidation is a prerequisite in fibril disruption. The results of this work demonstrate that oxidized EGCG plays a more important role than the intact molecule in anti-amyloidogenic activity. These insights into the action of EGCG may provide a novel route to understand the anti-amyloidogenic activity of natural polyphenols.

  12. Ubiquitous and continuous SAR imaging for natural hazards: present and future of remote sensing

    Science.gov (United States)

    Monti Guarnieri, Andrea; Rocca, Fabio

    2017-04-01

    Constellation of optical and SAR sensors have achieved unprecedented performances: dense constellation of cubesats - like the next constellation of 88 Dove satellites (Planet labs), launched simultaneously this February - reduce the revisit time to nearly daily. This brings great value to many domains, like the assessment of risk and damage in natural hazards, post-earthquake response, real time flood monitoring. The limits to optical imaging due to cloud coverage could then be removed with drones. Alternatively, decades of coherent exploitation of Synthetic Aperture Radars have demonstrated their unique capabilities in precise deformation monitoring, penetration in canopies and subsurfaces (glacier and deserts), 3D imaging of volumes, sensitivity to soil moisture and generation of water vapor maps. Thanks to these capabilities, for one, early warning was possible for a landslide at Bingham Canyon Mine (one of the largest in history), whereas monitoring of infrastructures, natural gas and carbon dioxide storage reservoirs, dams, mines is already an established business. Many of these applications are made possible by the Sentinel-1 SAR constellation, the first to provide systematic coherent acquisitions and free and open data. More than 50000 products are downloaded daily. Nonetheless, the present revisit times of this constellation (1-3 days), or the future 6 hours of Cosmo-SKYmed I and II constellations, will leave a gap that cannot be fruitfully exploited for early warning of landslides, real time mapping of flooding, hydrometeor forecasts, real-time regional alerts of collapse, continuous soil moisture mapping for precision farming. On the other side, the limited penetration capabilities of C-band (Sentinel-1) and X band (Cosmo, TerraSAR constellations) would not allow sufficient penetration to monitor volumes, like ice, sands and forests. In order to fill these gaps, two novel SAR systems are under study and will possibly appear in the next decades

  13. [THE PRESENT STATE OF EPIZOOTOLOGICAL MONITORING OF THE NATURAL FOCI OF INFECTIONS IN THE RUSSIAN FEDERATION].

    Science.gov (United States)

    Trankvilevsky, D V; Tsarenko, V A; Zhukov, V I

    2016-01-01

    The facilities of the Russian Federal Service for Supervision of Consumer Rights Protection and Human Welfare play a leading role in epizootological monitoring. The specialists (zoologists and entomologists) of Hygiene and Epidemiology Centers do basic work in the subjects of the Russian Federation. The data obtained in the participation of different ministries and departments are used to analyze the results of monitoring. The latter is one of the important steps in the management of the epidemic, process in natural focal infections. In recent years, there has been an unjustified reduction in the volume of studies in the natural foci. This negatively affects the reliability of estimates and predictions of the epidemic activity of the natural foci of infections. Ensuring the national, security of the Russian Federation, epidemiological surveillance, and control of its natural foci requires staffing and appropriate professional training in the zoological and entomological subdivisions of the Russian Federal Service for Supervision of Consumer Rights Protection and Human Welfare.

  14. Present Situation and Exploration Potentialities of Natural Gas Resources in Ordos Basin

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    @@ Ordos Basin is the second largest sedimentary basin in China, with an area of 370 thousand km2. Since the first onshore oil well was drilled successfully in northern Shaanxi of China, there has been a century of oil and gas exploration in the basin, and it may be said that the oil exploration has a long history, but for natural gas exploration, it still may be regarded as a new area, because large-scale research, exploration, and development of natural gas in the basin have relatively lagged. The four big gas fields of Jingbian, Sulige, Yulin, and Uxin Banner with respective reserves of more than one hundred giga cubic meters were discovered since 1990s[1]. Therefore,the basin has a great resources potential of natural gas and a low discovery ratio of gas reserves. The natural gas industry has broad prospects of development.

  15. Utilizing a Health Impact Assessment (HIA) to Connect Natural Resource Management and Community(presentation)

    Science.gov (United States)

    Marrying scientific and health research with natural resource management should be a straightforward process. However, differences in purpose, goals, language, levels of detail and implementation authority between the scientists who conduct research and resource managers who plan...

  16. Characteristics of hydration water around hen egg lysozyme as the protein model in aqueous solution. FTIR spectroscopy and molecular dynamics simulation.

    Science.gov (United States)

    Panuszko, Aneta; Wojciechowski, Marek; Bruździak, Piotr; Rakowska, Paulina W; Stangret, Janusz

    2012-12-05

    In this paper, the hydration of a model protein--hen egg white lysozyme in aqueous solution has been presented. The leading method used was FTIR spectroscopy with an application of a technique of semi-heavy water (HDO) isotope dilution. Analysis of spectra of HDO isotopically diluted in water solution of lysozyme allowed us to isolate HDO spectra affected by lysozyme, and thus to characterise the energetic state of water molecules and their arrangement around protein molecules. The number of water molecules and the shape of the affected HDO spectrum were obtained using a classical and a chemometric method. This shape showed that the HDO spectrum affected by lysozyme may be presented as a superposition of two spectra corresponding to HDO affected by N-methylacetamide and the carboxylate anion (of the formic acid). Moreover, based on the difference in intermolecular distances distribution of water molecules (obtained from spectral data), we demonstrated that the lysozyme molecule causes a decrease in population of weak hydrogen bonds, and concurrently increases the probability of an occurrence of short hydrogen bonds in water affected by lysozyme. This conclusion was also confirmed by the molecular dynamics (MD) simulation.

  17. Comparative study of gonadotropin levels and clinical presentation in surgical and natural menopause

    Directory of Open Access Journals (Sweden)

    Naik Raviraj R, Chandel Rittu S, Abichandani Leela G

    2014-03-01

    Full Text Available Introduction: Menopause means complete stoppage of menses for last one year due to failure of follicular activities of the ovaries. This can be determined by the various hormones secreted by ovary such as LH and FSH. As these hormones are responsible for normal maintenance of basic ovarian function in reproductive life; there occurs considerable alteration in their levels in menopause. Aims and Objectives :- 1] To study and compare ovarian function by determining levels of LH and FSH in Surgical and Natural menopause. 2] To study and compare ovarian function in Surgical and Natural menopause. Brief Methodology: – Case study: - 50 women with surgical menopause between 45 – 50 years of age. Control study: – 50 women with natural menopause between 45 – 50 years of age. Material & Methodolgy :- Fasting serum samples of all women with surgical and natural menopause were analysed for LH and FSH on Immulite 1000 chemiluminiscence based analyser in special investigation lab. Summary of the Results:- Mean levels of LH and FSH were higher in surgical menopausal women as compared to natural menopausal women. Women in surgical menopause suffered from more vasomotor symptoms and cognitive decline as compared to women in natural menopause group

  18. 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.

  19. 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

  20. 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.

  1. 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

  2. The inhibition of stuttering via the presentation of natural speech and sinusoidal speech analogs.

    Science.gov (United States)

    Saltuklaroglu, Tim; Kalinowski, Joseph

    2006-08-14

    Sensory signals containing speech or gestural (articulatory) information (e.g., choral speech) have repeatedly been found to be highly effective inhibitors of stuttering. Sine wave analogs of speech consist of a trio of changing pure tones representative of formant frequencies. They are otherwise devoid of traditional speech cues, yet have proven to evoke consistent linguistic percepts in listeners. Thus, we investigated the potency of sinusoidal speech for inhibiting stuttering. Ten adults who stutter read while listening to (a) forward-flowing natural speech; (b) forward-flowing sinusoid analogs of natural speech; (c) reversed natural speech; (d) reversed sinusoid analogs of natural speech; and (e) a continuous 1000 Hz pure tone. The levels of stuttering inhibition achieved using the sinusoidal stimuli were potent and not significantly different from those achieved using natural speech (approximately 50% in forward conditions and approximately 25% in the reversed conditions), suggesting that the patterns of undulating pure tones are sufficient to endow sinusoidal sentences with 'quasi-gestural' qualities. These data highlight the sensitivity of a specialized 'phonetic module' for extracting gestural information from sensory stimuli. Stuttering inhibition is thought to occur when perceived gestural information facilitates fluent productions via the engagement of mirror neurons (e.g., in Broca's area), which appear to play a crucial role in our ability to perceive and produce speech.

  3. Portal hypertensive gastropathy: A systematic review of the pathophysiology, clinical presentation, natural history and therapy.

    Science.gov (United States)

    Gjeorgjievski, Mihajlo; Cappell, Mitchell S

    2016-02-08

    To describe the pathophysiology, clinical presentation, natural history, and therapy of portal hypertensive gastropathy (PHG) based on a systematic literature review. Computerized search of the literature was performed via PubMed using the following medical subject headings or keywords: "portal" and "gastropathy"; or "portal" and "hypertensive"; or "congestive" and "gastropathy"; or "congestive" and "gastroenteropathy". The following criteria were applied for study inclusion: Publication in peer-reviewed journals, and publication since 1980. Articles were independently evaluated by each author and selected for inclusion by consensus after discussion based on the following criteria: Well-designed, prospective trials; recent studies; large study populations; and study emphasis on PHG. PHG is diagnosed by characteristic endoscopic findings of small polygonal areas of variable erythema surrounded by a pale, reticular border in a mosaic pattern in the gastric fundus/body in a patient with cirrhotic or non-cirrhotic portal hypertension. Histologic findings include capillary and venule dilatation, congestion, and tortuosity, without vascular fibrin thrombi or inflammatory cells in gastric submucosa. PHG is differentiated from gastric antral vascular ectasia by a different endoscopic appearance. The etiology of PHG is inadequately understood. Portal hypertension is necessary but insufficient to develop PHG because many patients have portal hypertension without PHG. PHG increases in frequency with more severe portal hypertension, advanced liver disease, longer liver disease duration, presence of esophageal varices, and endoscopic variceal obliteration. PHG pathogenesis is related to a hyperdynamic circulation, induced by portal hypertension, characterized by increased intrahepatic resistance to flow, increased splanchnic flow, increased total gastric flow, and most likely decreased gastric mucosal flow. Gastric mucosa in PHG shows increased susceptibility to gastrotoxic

  4. Portal hypertensive gastropathy: A systematic review of the pathophysiology, clinical presentation, natural history and therapy

    Science.gov (United States)

    Gjeorgjievski, Mihajlo; Cappell, Mitchell S

    2016-01-01

    AIM: To describe the pathophysiology, clinical presentation, natural history, and therapy of portal hypertensive gastropathy (PHG) based on a systematic literature review. METHODS: Computerized search of the literature was performed via PubMed using the following medical subject headings or keywords: “portal” and “gastropathy”; or “portal” and “hypertensive”; or “congestive” and “gastropathy”; or “congestive” and “gastroenteropathy”. The following criteria were applied for study inclusion: Publication in peer-reviewed journals, and publication since 1980. Articles were independently evaluated by each author and selected for inclusion by consensus after discussion based on the following criteria: Well-designed, prospective trials; recent studies; large study populations; and study emphasis on PHG. RESULTS: PHG is diagnosed by characteristic endoscopic findings of small polygonal areas of variable erythema surrounded by a pale, reticular border in a mosaic pattern in the gastric fundus/body in a patient with cirrhotic or non-cirrhotic portal hypertension. Histologic findings include capillary and venule dilatation, congestion, and tortuosity, without vascular fibrin thrombi or inflammatory cells in gastric submucosa. PHG is differentiated from gastric antral vascular ectasia by a different endoscopic appearance. The etiology of PHG is inadequately understood. Portal hypertension is necessary but insufficient to develop PHG because many patients have portal hypertension without PHG. PHG increases in frequency with more severe portal hypertension, advanced liver disease, longer liver disease duration, presence of esophageal varices, and endoscopic variceal obliteration. PHG pathogenesis is related to a hyperdynamic circulation, induced by portal hypertension, characterized by increased intrahepatic resistance to flow, increased splanchnic flow, increased total gastric flow, and most likely decreased gastric mucosal flow. Gastric mucosa

  5. Portal hypertensive gastropathy: A systematic review of thepathophysiology, clinical presentation, natural history andtherapy

    Institute of Scientific and Technical Information of China (English)

    2016-01-01

    AIM To describe the pathophysiology, clinical presentation,natural history, and therapy of portal hypertensivegastropathy (PHG) based on a systematic literaturereview.METHODS: Computerized search of the literature wasperformed via PubMed using the following medicalsubject headings or keywords: "portal" and "gastropathy";or "portal" and "hypertensive"; or "congestive"and "gastropathy"; or "congestive" and "gastroenteropathy".The following criteria were applied for studyinclusion: Publication in peer-reviewed journals, andpublication since 1980. Articles were independentlyevaluated by each author and selected for inclusionby consensus after discussion based on the followingcriteria: Well-designed, prospective trials; recent studies;large study populations; and study emphasis on PHG.RESULTS: PHG is diagnosed by characteristic endoscopicfindings of small polygonal areas of variableerythema surrounded by a pale, reticular border in amosaic pattern in the gastric fundus/body in a patientwith cirrhotic or non-cirrhotic portal hypertension. Histologicfindings include capillary and venule dilatation,congestion, and tortuosity, without vascular fibrinthrombi or inflammatory cells in gastric submucosa.PHG is differentiated from gastric antral vascular ectasiaby a different endoscopic appearance. The etiology ofPHG is inadequately understood. Portal hypertensionis necessary but insufficient to develop PHG becausemany patients have portal hypertension without PHG.PHG increases in frequency with more severe portalhypertension, advanced liver disease, longer liver diseaseduration, presence of esophageal varices, and endoscopicvariceal obliteration. PHG pathogenesis is related to ahyperdynamic circulation, induced by portal hypertension,characterized by increased intrahepatic resistance toflow, increased splanchnic flow, increased total gastricflow, and most likely decreased gastric mucosal flow.Gastric mucosa in PHG shows increased

  6. 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.

  7. The Effects of Thermal History on Nucleation of Tetragonal Lysozyme Crystals, or Hot Protein and Cold Nucleation

    Science.gov (United States)

    Burke, Michael; Judge, Russell; Pusey, Marc

    2000-01-01

    Chicken egg white lysozyme has a well characterized thermally driven phase transition. Between pH 4.2 and 5.2, the transition temperature, as defined by the point where the tetragonal and orthorhombic solubilities are equal, is a function of the pH, salt (precipitant) type and concentration, and most likely of the buffer concentration as well. This phase transition can be carried out with protein solution alone, prior to addition of precipitant solution. Warming a lysozyme solution above the phase transition point, then cooling it back below this point, has been shown to affect the subsequent nucleation rate, as determined by the numbers and size of crystals formed, but not the growth rate for the tetragonal crystal form . We have now measured the kinetics of this process and investigated its reversibility. The transition effects are progressive with temperature, having a half time of about 1 hour at 37C at pH 4.8. After holding a lysozyme solution at 37C (prior to addition of precipitant) for 16 hours, then cooling it back to 4C no return to the pre-warmed nucleation kinetics are observed after at least 4 weeks. Orthorhombic lysozyme crystals apparently do not undergo the flow-induced growth cessation of tetragonal lysozyme crystals. Putting the protein in the orthorhombic form does not affect the averaged face growth kinetics, only nucleation, for tetragonal crystals. This differential behaviour may be exploited to elucidate how and where flow affects the lysozyme crystal growth process. The presentation will focus on the results of these and ongoing studies in this area.

  8. 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.

  9. 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.

  10. 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.

  11. Yam tuber mucilage as a candidate substance for saliva substitute: in vitro study of its viscosity and influences on lysozyme and peroxidase activities.

    Science.gov (United States)

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

    2014-03-01

    To investigate the viscosity of yam tuber mucilage (YTM) and its effects on lysozyme and peroxidase activities in solution phase and on surface phase. Two kinds of YTM were extracted, one containing both protein and carbohydrate and the other containing mainly carbohydrate. Hen egg-white lysozyme and bovine lactoperoxidase were used as lysozyme and peroxidase sources, respectively. Viscosity was measured with a cone-and-plate digital viscometer. Lysozyme activity was determined using the turbidimetric method, and peroxidase activity was determined using the NbsSCN assay. Hydroxyapatite beads were used as a solid phase. The viscosity values of YTM followed a pattern of a non-Newtonian fluid. The carbohydrate concentration affected the viscosity values at all shear rates, while the protein concentration affected the viscosity values at low shear rates. It could be suggested that YTM composed of 1.0 mg/ml protein and 1.0 mg/ml carbohydrate has viscosity values similar to those of unstimulated whole saliva at shear rates present at routine oral functions. Hydroxyapatite-adsorbed YTM significantly increased the adsorption and subsequent enzymatic activities of lysozyme, but not those of peroxidase. Yam tuber mucilage has viscoelastic properties similar to those of human saliva and enhances the enzymatic activity of lysozyme on hydroxyapatite surfaces. © 2012 John Wiley & Sons A/S and The Gerodontology Association. Published by John Wiley & Sons Ltd.

  12. Open-Access Metabolomics Databases for Natural Product Research: Present Capabilities and Future Potential

    Science.gov (United States)

    Johnson, Sean R.; Lange, Bernd Markus

    2015-01-01

    Various databases have been developed to aid in assigning structures to spectral peaks observed in metabolomics experiments. In this review article, we discuss the utility of currently available open-access spectral and chemical databases for natural products discovery. We also provide recommendations on how the research community can contribute to further improvements. PMID:25789275

  13. Chemically reduced graphene contains inherent metallic impurities present in parent natural and synthetic graphite.

    Science.gov (United States)

    Ambrosi, Adriano; Chua, Chun Kiang; Khezri, Bahareh; Sofer, Zdeněk; Webster, Richard D; Pumera, Martin

    2012-08-07

    Graphene-related materials are in the forefront of nanomaterial research. One of the most common ways to prepare graphenes is to oxidize graphite (natural or synthetic) to graphite oxide and exfoliate it to graphene oxide with consequent chemical reduction to chemically reduced graphene. Here, we show that both natural and synthetic graphite contain a large amount of metallic impurities that persist in the samples of graphite oxide after the oxidative treatment, and chemically reduced graphene after the chemical reduction. We demonstrate that, despite a substantial elimination during the oxidative treatment of graphite samples, a significant amount of impurities associated to the chemically reduced graphene materials still remain and alter their electrochemical properties dramatically. We propose a method for the purification of graphenes based on thermal treatment at 1,000 °C in chlorine atmosphere to reduce the effect of such impurities on the electrochemical properties. Our findings have important implications on the whole field of graphene research.

  14. Chemically reduced graphene contains inherent metallic impurities present in parent natural and synthetic graphite

    Science.gov (United States)

    Ambrosi, Adriano; Chua, Chun Kiang; Khezri, Bahareh; Sofer, Zdeněk; Webster, Richard D.; Pumera, Martin

    2012-01-01

    Graphene-related materials are in the forefront of nanomaterial research. One of the most common ways to prepare graphenes is to oxidize graphite (natural or synthetic) to graphite oxide and exfoliate it to graphene oxide with consequent chemical reduction to chemically reduced graphene. Here, we show that both natural and synthetic graphite contain a large amount of metallic impurities that persist in the samples of graphite oxide after the oxidative treatment, and chemically reduced graphene after the chemical reduction. We demonstrate that, despite a substantial elimination during the oxidative treatment of graphite samples, a significant amount of impurities associated to the chemically reduced graphene materials still remain and alter their electrochemical properties dramatically. We propose a method for the purification of graphenes based on thermal treatment at 1,000 °C in chlorine atmosphere to reduce the effect of such impurities on the electrochemical properties. Our findings have important implications on the whole field of graphene research. PMID:22826262

  15. 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...

  16. 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.

  17. 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.

  18. Is the present Brackenridgea Nature Reserve large enough to ensure the survival of Brackenridgea zanguebarica Oliv.?

    Directory of Open Access Journals (Sweden)

    Milingoni P. Tshisikhawe

    2013-02-01

    Full Text Available The Brackenridgea Nature Reserve is a 110 ha protected area established by the provincial Limpopo Department of Economic Development, Environment and Tourism as a way of protecting the population of Brackenridgea zanguebarica, a species classified as critically endangered in South Africa. In the whole of South Africa, the species is found in only one small area around Thengwe–Mafukani in Venda. It is threatened with extirpation due to high demand for its medicinal bark. This study investigated the adequacy of the reserve to conserve the species using a method established in 2001 by Burgman et al. This method involves 12 steps to quantify the risk of the decline or possible extinction of the species and takes current human activities, disturbances and the viability of the population into consideration for setting a conservation target. From the results, it was clear that more area is needed for the current population to survive beyond 50 years. Assuming the status quo, it will require 410 ha to maintain the population, whereas a 50% reduction in human-related activities, such as cultivation, harvesting and livestock grazing, will lower the required potential habitat to 203 ha and a conservation option, which allows for bark harvesting, will require 179 ha. Conservation implications: The results of this study will have conservation implication on management of viable species population within a nature reserve. It will require managers to take into consideration the reserve size in relation to potential habitats for the development of species under their management.

  19. Natural Laws and Ontological Reflections: The Textual and Didactic Implications of the Presentation of Boyle's Law in General Chemistry

    Science.gov (United States)

    Quiroz, Waldo; Rubilar, Cristian Merino

    2015-01-01

    This study develops a tool to identify errors in the presentation of natural laws based on the epistemology and ontology of the Scientific Realism of Mario Bunge. The tool is able to identify errors of different types: (1) epistemological, in which the law is incorrectly presented as data correlation instead of as a pattern of causality; (2)…

  20. Natural Laws and Ontological Reflections: The Textual and Didactic Implications of the Presentation of Boyle's Law in General Chemistry

    Science.gov (United States)

    Quiroz, Waldo; Rubilar, Cristian Merino

    2015-01-01

    This study develops a tool to identify errors in the presentation of natural laws based on the epistemology and ontology of the Scientific Realism of Mario Bunge. The tool is able to identify errors of different types: (1) epistemological, in which the law is incorrectly presented as data correlation instead of as a pattern of causality; (2)…

  1. Realist Ontology and Natural Processes: A Semantic Tool to Analyze the Presentation of the Osmosis Concept in Science Texts

    Science.gov (United States)

    Spinelli Barria, Michele; Morales, Cecilia; Merino, Cristian; Quiroz, Waldo

    2016-01-01

    In this work, we developed an ontological tool, based on the scientific realism of Mario Bunge, for the analysis of the presentation of natural processes in science textbooks. This tool was applied to analyze the presentation of the concept of osmosis in 16 chemistry and biology books at different educational levels. The results showed that more…

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. How the nature of science is presented to elementary students in science read-alouds

    Science.gov (United States)

    Rivera, Seema

    Students as early as elementary school age are capable of learning the aspects of the nature of science (NOS), and the National Benchmarks incorporate the NOS as part of the learning objectives for K--2 students. Learning more about elementary science instruction can aid in understanding how the NOS can be taught or potentially integrated into current teaching methods. Although many teaching methods exist, this study will focus on read-alouds because they are recommended for and are very common in elementary schools. The read-aloud practice is particularly helpful to young students because most of these students have a higher listening comprehension than reading comprehension. One of the main components of the read-aloud practice is the discourse that takes place about the trade book. Both explicit and implicit messages are communicated to students by teachers' language and discussion that takes place in the classroom. Therefore, six multisite naturalistic case studies were conducted to understand elementary teachers' understanding of the NOS, students' understandings of the NOS, trade book representations of the NOS, and read-aloud practices and understandings in upstate New York. The findings of the study revealed that teachers and students held mostly naive and mixed understandings of the NOS. The trade books that had explicit connections to the NOS helped teachers discuss NOS related issues, even when the teachers did not hold strong NOS views. Teachers who held more informed NOS views were able to ask students NOS related questions. All teachers showed they need guidance on how to translate their NOS views into discussion and see the significance of the NOS in their classroom. Explicit NOS instruction can improve student understanding of the NOS, however the focus should be not only on teachers and their NOS understanding but also on the books used. These results show that quality trade books with explicit connections to the NOS are a useful instructional tool

  9. Organic compounds present in the natural Amazonian aerosol: Characterization by gas chromatography-mass spectrometry

    Science.gov (United States)

    Graham, Bim; Guyon, Pascal; Taylor, Philip E.; Artaxo, Paulo; Maenhaut, Willy; Glovsky, M. Michael; Flagan, Richard C.; Andreae, Meinrat O.

    2003-12-01

    As part of the Large-Scale Biosphere-Atmosphere Experiment in Amazonia (LBA)-Cooperative LBA Airborne Regional Experiment (CLAIRE) 2001 campaign in July 2001, separate day and nighttime aerosol samples were collected at a ground-based site in Amazonia, Brazil, in order to examine the composition and temporal variability of the natural "background" aerosol. We used a high-volume sampler to separate the aerosol into fine (aerodynamic diameter, AD 2.5 μm) size fractions and quantified a range of organic compounds in methanolic extracts of the samples by a gas chromatographic-mass spectrometric technique. The carbon fraction of the compounds could account for an average of 7% of the organic carbon (OC) in both the fine and coarse aerosol fractions. We observed the highest concentrations of sugars, sugar alcohols, and fatty acids in the coarse aerosol samples, which suggests that these compounds are associated with primary biological aerosol particles (PBAP) observed in the forest atmosphere. Of these, trehalose, mannitol, arabitol, and the fatty acids were found to be more prevalent at night, coinciding with a nocturnal increase in PBAP in the 2-10 μm size range (predominantly yeasts and other small fungal spores). In contrast, glucose, fructose, and sucrose showed persistently higher daytime concentrations, coinciding with a daytime increase in large fungal spores, fern spores, pollen grains, and, to a lesser extent, plant fragments (generally >20 μm in diameter), probably driven by lowered relative humidity and enhanced wind speeds/convective activity during the day. For the fine aerosol samples a series of dicarboxylic and hydroxyacids were detected with persistently higher daytime concentrations, suggesting that photochemical production of a secondary organic aerosol from biogenic volatile organic compounds may have made a significant contribution to the fine aerosol. Anhydrosugars (levoglucosan, mannosan, galactosan), which are specific tracers for biomass

  10. Chloroquine inhibits accessory cell presentation of soluble natural and synthetic protein antigens

    DEFF Research Database (Denmark)

    Buus, S; Werdelin, O

    1984-01-01

    was time- and dose-dependent. A brief treatment solely of the accessory cells with the drug compromised their ability to stimulate primed T cells in a subsequent culture provided the accessory cells were treated with chloroquine before their exposure to the antigen. These results suggest that chloroquine......We have studied the in vitro effect of the lysosomotrophic agent, chloroquine, on the presentation of soluble protein antigens by guinea pig accessory cells. Chloroquine inhibited the capacity of antigen-pulsed accessory cells to stimulate proliferation in appropriately primed T cells. The effect...

  11. 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.

  12. 21 CFR 110.110 - Natural or unavoidable defects in food for human use that present no health hazard.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 2 2010-04-01 2010-04-01 false Natural or unavoidable defects in food for human use that present no health hazard. 110.110 Section 110.110 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN CONSUMPTION CURRENT GOOD MANUFACTURING PRACTICE IN MANUFACTURING, PACKING,...

  13. Outlining Purposes, Stating the Nature of the Present Research, and Listing Research Questions or Hypotheses in Academic Papers

    Science.gov (United States)

    Shehzad, Wasima

    2011-01-01

    Driving research questions from the prevailing issues and interests and developing from them new theories, formulas, algorithms, methods, and designs, and linking them to the interests of the larger audience is a vital component of scientific research papers. The present article discusses outlining purposes or stating the nature of the present…

  14. 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.

  15. Inhibition of hepatitis C virus replication in vitro by xanthohumol, a natural product present in hops.

    Science.gov (United States)

    Lou, Sai; Zheng, Yi-Min; Liu, Shan-Lu; Qiu, Jianming; Han, Qunying; Li, Na; Zhu, Qianqian; Zhang, Pingping; Yang, Cuiling; Liu, Zhengwen

    2014-02-01

    Hepatitis C virus is a major cause of chronic liver disease worldwide. Xanthohumol, a prenylated flavonoid from hops, has various biological activities including an antiviral effect. It was previously characterized as a compound that inhibits bovine viral diarrhea virus, a surrogate model of hepatitis C virus. In the present work, xanthohumol was examined for its ability to inhibit hepatitis C virus replication in a cell culture system carrying replicating hepatitis C virus RNA replicon. 0.2 % DMSO and 500 units/mL interferon-alpha treatments were set as a negative and positive control, respectively. The inhibitory effect by xanthohumol was determined by the luciferase activity of the infected Huh7.5 cell lysates and the hepatitis C virus RNA levels in the culture. Xanthohumol at 3.53 µM significantly decreased the luciferase activity compared to the negative control (p Xanthohumol at 7.05 µM further decreased the luciferase activity compared to xanthohumol at 3.53 µM (p = 0.015). Xanthohumol at 7.05 µM or 14.11 µM achieved an inhibitory effect similar to that of interferon-alpha 2b (p > 0.05). Xanthohumol at 3.53 µM significantly reduced the hepatitis C virus RNA level compared to the negative control (p = 0.001). Although the results of xanthohumol at 7.05 µM had a higher variation, xanthohumol at the 7.05 µM and 14.11 µM decreased the hepatitis C virus RNA level to that achieved by interferon-alpha (p > 0.05). In conclusion, xanthohumol displays anti-hepatitis C virus activity in a cell culture system and may be potentially used as an alternative or complementary treatment against the hepatitis C virus.

  16. The Effect of Visual Display Properties and Gain Presentation Mode on the Perceived Naturalness of Virtual Walking Speeds

    DEFF Research Database (Denmark)

    Nilsson, Niels Chr.; Serafin, Stefania; Nordahl, Rolf

    2015-01-01

    Individuals tend to find realistic walking speeds too slow when relying on treadmill walking or Walking-In-Place (WIP) techniques for virtual travel. This paper details three studies investigating the effects of visual display properties and gain presentation mode on the perceived naturalness...... of virtual walking speeds: The first study compared three different degrees of peripheral occlusion; the second study compared three different degrees of perceptual distortion produced by varying the geometric field of view (GFOV); and the third study compared three different ways of presenting visual gains...... of the visual speed. The third study found a significant main effect of gain presentation mode. Allowing participants to interactively adjust the gain led to a smaller range of perceptually natural gains and this approach was significantly faster. However, the efficiency may come at the expense of confidence...

  17. 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.

  18. 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.

  19. 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...

  20. 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

  1. Influence of rotation speed on natural frequency: A short introduction and presentation of an imaginary 'antigravity' world

    CERN Document Server

    Provatidis, Christopher G

    2011-01-01

    We present an instructive way to introduce the subject of resonance using a typical spring-mass system without damping. In contrast to the standard approach found in most textbooks, here we propose a way to extend the lectures from common translational systems to rotating ones. In the latter case, particular attention is paid to the role of the variable centripetal force. The students will find analytical solutions of the simplest possible ordinary differential equations of motion and see that the natural frequency strongly depends on the rotation speed, the latter being a simple vector sum. The analysis reveals that always the resultant ground force is harmonic. In order to depict the significance in the influence of rotation on natural frequency, we present an imaginary 'antigravity' world in which the aforementioned dependency is absent.

  2. 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.

  3. Nanowires: Quantitative Probing of Cu(2+) Ions Naturally Present in Single Living Cells (Adv. Mater. 21/2016).

    Science.gov (United States)

    Lee, Junho; Lee, Hwa-Rim; Pyo, Jaeyeon; Jung, Youngseob; Seo, Ji-Young; Ryu, Hye Guk; Kim, Kyong-Tai; Je, Jung Ho

    2016-06-01

    Quantitative probing of the Cu(2+) ions naturally present in single living cells is accomplished by a probe made from a quantum-dot-embedded-nanowire waveguide. After inserting the active nanowire-based waveguide probe into single living cells, J. H. Je and co-workers directly observe photoluminescence (PL) quenching of the embedded quantum dots by the Cu(2+) ions diffused into the probe as described on page 4071. This results in quantitative measurement of intracellular Cu(2+) ions.

  4. 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.

  5. T4 phage lysozyme: a protein designed for understanding tryptophan photophysics

    Science.gov (United States)

    Hudson, Bruce S.; Harris, Dan

    1990-05-01

    Bacteriophage T4 lysozyme in its wild type form contains three tryptophan residues (at sequence postions 126, 138 and 158). These three residues are in rather different environments in the protein: 126 and 158 are near the protein surface while residue 138 is more buried. T4 lysozyme has been genetically engineered to prepare all possible variants in which one or more of the tryptophan residues have been replaced by tyrosine. The available data supports the hypothesis that this substitution has, at most, a very minor effect on the structure of the protein. The three species with single tryptophan residues have been investigated in detail. The surface location of residue 126 compared to the buried location of residue 138 is reflected in the difference in collisional quenching observed with added potassium iodide. It is found that the spectral and radiative properties of the three proteins are very similar but that their radiationless decay properties are quite distinct. This is apparently due to short-range collisional quenching by neighboring side chains. Comparison with solution quenching measurements permits the identification of the specific quenching groups involved for each tryptophan residue and provides a semi-quantitative rationale for the radiationless decay rate. This collisional quenching interpretation is supported by mutational effects on fluorescence quantum yield. This simple picture of the behavior of these single-tryptophan proteins is clearly revealed in this particular case because of the unambiguous choice of collisional quenching groups. The time dependence of the fluorescence decay of each of these single-tryptophan proteins is quite complex. Several methods of analysis are presented and discussed in terms of their underlying physical basis. Internal collisional quenching, as suggested from the comparative studies, is expected to lead to non-exponential behavior. This is consistent with the observed time dependence. Analysis of the temporal

  6. 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...

  7. 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.

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

    Directory of Open Access Journals (Sweden)

    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.

  9. 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.

  10. Chaperonin-Inspired pH Protection by Mesoporous Silica SBA-15 on Myoglobin and Lysozyme.

    Science.gov (United States)

    Lynch, Michele M; Liu, Jichuan; Nigra, Michael; Coppens, Marc-Olivier

    2016-09-20

    While enzymes are valuable tools in many fields of biotechnology, they are fragile and must be protected against denaturing conditions such as unfavorable solution pH. Within living organisms, chaperonins help enzymes fold into their native shape and protect them from damage. Inspired by this natural solution, mesoporous silica SBA-15 with different pore diameters is synthesized as a support material for immobilizing and protecting enzymes. In separate experiments, the model enzymes myoglobin and lysozyme are physically adsorbed to SBA-15 and exposed to a range of buffered pH conditions. The immobilized enzymes' biocatalytic activities are quantified and compared to the activities of nonimmobilized enzymes in the same solution conditions. It has been observed that myoglobin immobilized on SBA-15 is protected from acidic denaturation from pH 3.6 to 5.1, exhibiting relative activity of up to 350%. Immobilized lysozyme is protected from unfavorable conditions from pH 6.6 to 7.6, with relative activity of up to 200%. These results indicate that the protective effects conferred to enzymes immobilized by physical adsorption to SBA-15 are driven by the enzymes' electrostatic attraction to the material's surface. The pore diameter of SBA-15 affects the quality of protection given to immobilized enzymes, but the contribution of this effect at different pH values remains unclear.

  11. 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,...

  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. Attempts to use pulsed light as an emerging technology for inactivation of mould naturally present on rye

    OpenAIRE

    NICOLETA ARON MAFTEI; ANA RAMOS-VILLARROEL; ANCA NICOLAU; OLGA MARTIN-BELLOSO

    2011-01-01

    Pulsed light technology was used to inactivate moulds, naturally present on rye. The experiments were performed on samples containing 3.5·104 CFU/g and 4.3·103 CFU/g. Treatments of different duration (5, 10, 15, 20, 30, and 40 pulses) at intensity of 0.4 J·cm-2 per pulse were applied and mould inactivation was evaluated. Besides confirming the utilisation of pulsed light as decontamination method for cereals, this work contributes with new information regarding the effects of the spectral ran...

  14. 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.

  15. Human natural killer cells promote cross-presentation of tumor cell-derived antigens by dendritic cells.

    Science.gov (United States)

    Deauvieau, Florence; Ollion, Vincent; Doffin, Anne-Claire; Achard, Carole; Fonteneau, Jean-François; Verronese, Estelle; Durand, Isabelle; Ghittoni, Raffaella; Marvel, Jacqueline; Dezutter-Dambuyant, Colette; Walzer, Thierry; Vie, Henri; Perrot, Ivan; Goutagny, Nadège; Caux, Christophe; Valladeau-Guilemond, Jenny

    2015-03-01

    Dendritic cells (DCs) cross-present antigen (Ag) to initiate T-cell immunity against most infections and tumors. Natural killer (NK) cells are innate cytolytic lymphocytes that have emerged as key modulators of multiple DC functions. Here, we show that human NK cells promote cross-presentation of tumor cell-derived Ag by DC leading to Ag-specific CD8(+) T-cell activation. Surprisingly, cytotoxic function of NK cells was not required. Instead, we highlight a critical and nonredundant role for IFN-γ and TNF-α production by NK cells to enhance cross-presentation by DC using two different Ag models. Importantly, we observed that NK cells promote cell-associated Ag cross-presentation selectively by monocytes-derived DC (Mo-DC) and CD34-derived CD11b(neg) CD141(high) DC subsets but not by myeloid CD11b(+) DC. Moreover, we demonstrate that triggering NK cell activation by monoclonal antibodies (mAbs)-coated tumor cells leads to efficient DC cross-presentation, supporting the concept that NK cells can contribute to therapeutic mAbs efficiency by inducing downstream adaptive immunity. Taken together, our findings point toward a novel role of human NK cells bridging innate and adaptive immunity through selective induction of cell-associated Ag cross-presentation by CD141(high) DC, a process that could be exploited to better harness Ag-specific cellular immunity in immunotherapy. © 2014 UICC.

  16. A new bovine conjunctiva model shows that Listeria monocytogenes invasion is associated with lysozyme resistance.

    Science.gov (United States)

    Warren, Jessica; Owen, A Rhys; Glanvill, Amy; Francis, Asher; Maboni, Grazieli; Nova, Rodrigo J; Wapenaar, Wendela; Rees, Catherine; Tötemeyer, Sabine

    2015-08-31

    Listerial keratoconjunctivitis ('silage eye') is a wide spread problem in ruminants causing economic losses to farmers and impacts negatively on animal welfare. It results from direct entry of Listeria monocytogenes into the eye, often following consumption of contaminated silage. An isolation protocol for bovine conjunctival swabbing was developed and used to sample both infected and healthy eyes bovine eyes (n=46). L. monocytogenes was only isolated from one healthy eye sample, and suggests that this organism can be present without causing disease. To initiate a study of this disease, an infection model was developed using isolated conjunctiva explants obtained from cattle eyes post slaughter. Conjunctiva were cultured and infected for 20 h with a range of L. monocytogenes isolates (n=11), including the healthy bovine eye isolate and also strains isolated from other bovine sources, such as milk or clinical infections. Two L. monocytogenes isolates (one from a healthy eye and one from a cattle abortion) were markedly less able to invade conjunctiva explants, but one of those was able to efficiently infect Caco2 cells indicating that it was fully virulent. These two isolates were also significantly more sensitive to lysozyme compared to most other isolates tested, suggesting that lysozyme resistance is an important factor when infecting bovine conjunctiva. In conclusion, we present the first bovine conjunctiva explant model for infection studies and demonstrate that clinical L. monocytogenes isolates from cases of bovine keratoconjunctivitis are able to infect these tissues.

  17. 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....

  18. Lysophospholipid presentation by CD1d and recognition by a human Natural Killer T-cell receptor

    Energy Technology Data Exchange (ETDEWEB)

    López-Sagaseta, Jacinto; Sibener, Leah V.; Kung, Jennifer E.; Gumperz, Jenny; Adams, Erin J. (UC); (UW-MED)

    2014-10-02

    Invariant Natural Killer T (iNKT) cells use highly restricted {alpha}{beta} T cell receptors (TCRs) to probe the repertoire of lipids presented by CD1d molecules. Here, we describe our studies of lysophosphatidylcholine (LPC) presentation by human CD1d and its recognition by a native, LPC-specific iNKT TCR. Human CD1d presenting LPC adopts an altered conformation from that of CD1d presenting glycolipid antigens, with a shifted {alpha}1 helix resulting in an open A pocket. Binding of the iNKT TCR requires a 7-{angstrom} displacement of the LPC headgroup but stabilizes the CD1d-LPC complex in a closed conformation. The iNKT TCR CDR loop footprint on CD1d-LPC is anchored by the conserved positioning of the CDR3{alpha} loop, whereas the remaining CDR loops are shifted, due in part to amino-acid differences in the CDR3{beta} and J{beta} segment used by this iNKT TCR. These findings provide insight into how lysophospholipids are presented by human CD1d molecules and how this complex is recognized by some, but not all, human iNKT cells.

  19. Extraction of Thermodynamic Data from Ternary Diffusion Coefficients of Lysozyme Chloride in Water and Aqueous Na$_2$SO$_4$

    CERN Document Server

    Buzatu, D; Buzatu, F D; Albright, J G

    2004-01-01

    This paper presents, for ternary lysozyme-Na$_2$SO$_4$-water system, the thermodynamic data extracted from the measured values of four ternary diffusion coefficients and the Onsager reciprocal relations. The calculation for derivatives of solute chemical potentials with respect to solute molar concentrations was made using the method presented in \\cite{1}. This method is applicable to systems in which the molar concentration of one solute is very small compared to that of the other, like in our case. The approach is illustrated for the lysozyme chloride-Na$_2$SO$_4$-water system at 25$^o$ C, pH 4.5 and at 0.6 mM (8.6 mg/mL) lysozyme chloride and 0.1, 0.25, 0.5, 0.65, and 0.8 M Na$_2$SO$_4$ concentrations. The calculated solute chemical potential derivatives were used to compute the protein cation charge approximately. We also compute the diffusion Onsager coefficients $(L_{ij})_o$ for each composition at pH 4.5.

  20. 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.

  1. 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.

  2. 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.

  3. 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.

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

    Directory of Open Access Journals (Sweden)

    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.

  5. 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.

  6. Possible Influence of Resistance to Malaria in Clinical Presentation of Rheumatoid Arthritis: Biological Significance of Natural Selection

    Directory of Open Access Journals (Sweden)

    Fabio Bonilla-Abadía

    2012-01-01

    Full Text Available Rheumatoid arthritis (RA is a common autoimmune disease that affects all ethnic groups. Genetic factors, mainly HLA alleles, are highly associated with increased risk to develop RA. However, there are few available data about the role of these genetic polymorphisms in the prevalence or severity of RA in the Afrodescendant population, who have evolutionarily and by natural selection developed mutations that allowed them to acquire resistance to infectious diseases like malaria. Some of the mechanisms, by which this resistance was developed as a product of natural selection, are involved in different forms of immunological response, many of them of a well-known importance in the pathophysiology of RA. This paper focuses on presenting the known mechanisms of resistance to malaria and their possible contribution to the pathophysiology of RA, including “loss-of-function” mutations, lack of expression of chemokine receptors, decrease of immune complexes clearance by asplenia, or increase of immune reactivity mediated by B cells, among other mechanisms in this special group of patients.

  7. High-pressure protein crystallography of hen egg-white lysozyme

    Energy Technology Data Exchange (ETDEWEB)

    Yamada, Hiroyuki; Nagae, Takayuki [Nagoya University, Chikusa, Nagoya, Aichi 464-8603 (Japan); Watanabe, Nobuhisa, E-mail: nobuhisa@nagoya-u.jp [Nagoya University, Chikusa, Nagoya, Aichi 464-8603 (Japan); Nagoya University, Chikusa, Nagoya, Aichi 464-8603 (Japan)

    2015-04-01

    The crystal structure of hen egg-white lysozyme (HEWL) was analyzed under pressures of up to 950 MPa. The high pressure modified the conformation of the molecule and induced a novel phase transition in the tetragonal crystal of HEWL. Crystal structures of hen egg-white lysozyme (HEWL) determined under pressures ranging from ambient pressure to 950 MPa are presented. From 0.1 to 710 MPa, the molecular and internal cavity volumes are monotonically compressed. However, from 710 to 890 MPa the internal cavity volume remains almost constant. Moreover, as the pressure increases to 950 MPa, the tetragonal crystal of HEWL undergoes a phase transition from P4{sub 3}2{sub 1}2 to P4{sub 3}. Under high pressure, the crystal structure of the enzyme undergoes several local and global changes accompanied by changes in hydration structure. For example, water molecules penetrate into an internal cavity neighbouring the active site and induce an alternate conformation of one of the catalytic residues, Glu35. These phenomena have not been detected by conventional X-ray crystal structure analysis and might play an important role in the catalytic activity of HEWL.

  8. Synthesis of Self-assembled Noble Metal Nanoparticle Chains Using Amyloid Fibrils of Lysozyme as Templates

    Directory of Open Access Journals (Sweden)

    Ziming Xu

    2016-01-01

    Full Text Available We reported a facile method for preparing self-assembled noble metal nanoparticle chains by using lysozyme amyloid fibrils as a biotemplate in an aqueous environ‐ ment. The nanoparticle chains of gold (AuNPCs, palladi‐ um (PdNPCs, platinum (PtNPCs and rhodium (RhNPCs, which are lysozyme fibrils coated by gold, palladium, platinum and rhodium nanoparticles, can be fabricated by simply reducing the corresponding metal salt precursors using NaBH4. Under the same molar ratio between salt precursors and fibrils, two types of morphologies of high- yield AuNPCs (thin- and thick- AuNPCs were synthesized as a result of adjusting the fibrosis time and temperature in the final stage. Abundant PdNPCs with a length of several micrometres intertwisted with each other to form PdNPC networks. The growth of RhNPCs started from the inner surface of the fibrils and gradually spread to the whole fibre as superabundant rhodium nanoparticles (RhNPs bound to the fibrils. Finally, PtNPCs at different growing periods were presented. The nanostructures were investigated by transmission electron microscope, UV-visible spectrosco‐ py, fluorescence spectroscopy, energy-dispersive X-ray spectroscopy and atomic force microscope.

  9. AFM Studies of Salt Concentration Effects on the (110) Surface Structure of Tetragonal Lysozyme Crystals

    Science.gov (United States)

    Pusey, Marc Lee; Gorti, Sridhar; Forsythe, Elizabeth; Konnert, John

    2002-01-01

    Previous high resolution AFM studies of the (110) surface of tetragonal chicken egg white lysozyme crystals had shown that only one of two possible molecular surfaces is present, those constituting the completed 43 helices. These suggested that the crystal growth process was by the solution-phase assembly of the growth units, which then attach to the surface. However, the best fit for the imaged surfaces, vs. those predicted based upon the bulk crystallographic coordinates, were obtained when the packing about the 43 helices was "tightened up", while maintaining the underlying crystallographic unit cell spacing. This results in a widening of the gap between adjacent helices, and the top- most layer(s) may no longer be in contact. We postulated that the tightened packing about the helices is a result of the high salt concentrations in the bulk solution, used to crystallize the protein, driving hydrophobic interactions. Once the crystal surface is sufficiently buried by subsequent growth layers the ratio of salt to protein molecules decreases and the helices relax to their bulk crystallographic coordinates. The crystal surface helix structure is thus a reflection of the solution structure, and the tightness of the packing about the 43 helices would be a function of the bulk salt concentration. AFM images of the (110) surface of tetragonal lysozyme crystals grown under low (2%) and high (5%) NaCl concentrations reveal differences in the packing about the 43 helices consistent with the above proposal.

  10. U.S. Natural Gas System Methane Emissions: State of Knowledge from LCAs, Inventories, and Atmospheric Measurements (Presentation)

    Energy Technology Data Exchange (ETDEWEB)

    Heath, G.

    2014-04-01

    Natural gas (NG) is a potential "bridge fuel" during transition to a decarbonized energy system: It emits less carbon dioxide during combustion than other fossil fuels and can be used in many industries. However, because of the high global warming potential of methane (CH4, the major component of NG), climate benefits from NG use depend on system leakage rates. Some recent estimates of leakage have challenged the benefits of switching from coal to NG, a large near-term greenhouse gas (GHG) reduction opportunity. During this presentation, Garvin will review evidence from multiple perspectives - life cycle assessments (LCAs), inventories and measurements - about NG leakage in the US. Particular attention will be paid to a recent article in Science magazine which reviewed over 20 years of published measurements to better understand what we know about total methane emissions and those from the oil and gas sectors. Scientific and policy implications of the state of knowledge will be discussed.

  11. Attempts to use pulsed light as an emerging technology for inactivation of mould naturally present on rye

    Directory of Open Access Journals (Sweden)

    NICOLETA ARON MAFTEI

    2011-12-01

    Full Text Available Pulsed light technology was used to inactivate moulds, naturally present on rye. The experiments were performed on samples containing 3.5·104 CFU/g and 4.3·103 CFU/g. Treatments of different duration (5, 10, 15, 20, 30, and 40 pulses at intensity of 0.4 J·cm-2 per pulse were applied and mould inactivation was evaluated. Besides confirming the utilisation of pulsed light as decontamination method for cereals, this work contributes with new information regarding the effects of the spectral range of pulsed light, proving that the whole UV range of the spectrum accounts for the lethal effect against moulds. This research supports pulsed light as emerging technology in food preservation.

  12. Extranodal natural killer cell/t-cell lymphoma, nasal type, presenting as cutaneous nodules and a small-bowel perforation.

    Science.gov (United States)

    Agarwal, Priyanka; Ruzinova, Marianna B; Harris, Marian H; Qureshi, Abrar A; Stebbins, William G

    2010-02-01

    Extranodal natural killer (NK) cell/T-cell lymphoma, nasal type, is a rare aggressive neoplasm, most commonly presenting as a destructive lesion in the nasal cavity and nasopharynx in middle-aged to older adults. About one third of cases present in an extranasal location, commonly involving skin and gastrointestinal tract, and usually occur in the absence of superficial lymphadenopathy. Diagnosis of this malignancy can be missed given its rarity and heterogeneous presentation. We describe a patient with an extranodal NK cell/T-cell lymphoma, nasal type, who was initially diagnosed and treated for a presumed Mycobacterium marinum infection, after biopsies were unrevealing. However, after more serious complications developed, repeat biopsy was performed. An atypical lymphocytic infiltrate was noted, with cells being positive for NK cell/T-cell markers CD2, CD7, and CD3 (subset), as well as for cytotoxic lymphocyte markers perforin, T-cell intracellular antigen, and CD56. In situ hybridization for Epstein-Barr virus-encoded RNA was also positive. This case demonstrates an important diagnostic pitfall of confusing cutaneous involvement by an aggressive NK cell/T-cell lymphoma with an antibiotic-resistant infection. Repeat biopsies and close clinicopathologic correlation are essential for establishment of correct diagnosis.

  13. Nasal Type Extranodal Natural Killer/T (NK/T) Cell Lymphoma Presenting as Periorbital Cellulitis: A Case Report

    Science.gov (United States)

    Shawabkeh, Ma’in Ali Al; Sulaiti, Mansour Al; Sa’ey, Hamad Al; Ganesan, Shanmugam

    2016-01-01

    Patient: Male, 25 Final Diagnosis: Nasal type • extra nodal NK/T-cell lymphoma Symptoms: Left periorbital swelling • redness • pain for 25 days • yellowish eye discharge associated • headache • fever Medication: — Clinical Procedure: — Specialty: Otolaryngology Objective: Unusual clinical course Background: Extranodal lymphoma of the paranasal sinuses is a rare clinical entity seen in only 5–8% of extranodal lymphomas of the head and neck. Nasal natural killer/T cell lymphoma (Nasal NKTCL), which is a subtype of peripheral T cell lymphoma, constitutes about 1.4% of all lymphomas. NKTCL is usually diagnosed at a late stage because it presents with nonspecific symptoms in the early stages. Case Report: We report the case of a 25-year-old male patient who presented with periorbital swelling treated as fungal sinusitis but proven to have NKTCL. We review the literature and discuss the clinical manifestations of the disease, its relation to EBV virus, the histological and radiological characteristics, the prognostic indicators, and treatment options. This case report shows physicians that NKTCL lymphoma can present as periorbital cellulitis, although few similar cases are found in the literature. Conclusions: NKTCL is a destructive midline tumor that should be kept in mind as a differential diagnosis of paranasal sinus lesions to help in early diagnosis, which can improve the prognosis. PMID:27932776

  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. 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.

  19. Effects of the aromatase inhibitor Letrozole on serum immunoglobulin and lysozyme levels in immunized rainbow trout (Oncorhynchus mykiss Walbaum females

    Directory of Open Access Journals (Sweden)

    Paria Akbary

    2013-12-01

    Full Text Available Letrozole is a synthetic aromatase inhibitor and interfere in the committed step in the synthesis of endogenous estrogens from androgens. Also estrogens regulate the immune system in teleost. Changes of 17- β- esrtradiol (E2, serum immunoglobulin and lysozyme levels were measured using a method based on the ability of lysozyme to lyse the bacterium Micrococcus lysodeikticus, enzyme-linked immunosorbent assay (ELISA and ELISA respectively. Twelve broodstocks were injected weekly with 2.5 mg kg-1 letrozole (an endocrine disrupter component two months before spawning season and vaccinated intraperitoneally (i.p with a bacterin (inactivated L. garviae one month before spawning. Twelve broodstocks for vaccination and twelve female rainbow trout as control group were also immiunised (i.p with the bacterin and injected (i.p with PBS, respectively. In the group received 2.5 mg AI kg-1 per week, serum E2 levels were significantly lower than that of other groups. Total immunoglobulin level and lysozyme activity were significantly higher in the parents received 2.5 mg kg-1 per week and were immunized with 10-9 cells ml-1 Lactococcus garvieae  compared to the group which immunized with L. garvieae and the control (non- immunized. The present study, suggests that aromatase inhibitors such as letrozole may be a potential tool to regulate the synthesis of E2, is involved in the hormone- immune system interaction in rainbow trout.

  20. Hiding Lipid Presentation: Viral Interference with CD1d-Restricted Invariant Natural Killer T (iNKT Cell Activation

    Directory of Open Access Journals (Sweden)

    Maaike E. Ressing

    2012-10-01

    Full Text Available The immune system plays a major role in protecting the host against viral infection. Rapid initial protection is conveyed by innate immune cells, while adaptive immunity (including T lymphocytes requires several days to develop, yet provides high specificity and long-lasting memory. Invariant natural killer T (iNKT cells are an unusual subset of T lymphocytes, expressing a semi-invariant T cell receptor together with markers of the innate NK cell lineage. Activated iNKT cells can exert direct cytolysis and can rapidly release a variety of immune-polarizing cytokines, thereby regulating the ensuing adaptive immune response. iNKT cells recognize lipids in the context of the antigen-presenting molecule CD1d. Intriguingly, CD1d-restricted iNKT cells appear to play a critical role in anti-viral defense: increased susceptibility to disseminated viral infections is observed both in patients with iNKT cell deficiency as well as in CD1d- and iNKT cell-deficient mice. Moreover, viruses have recently been found to use sophisticated strategies to withstand iNKT cell-mediated elimination. This review focuses on CD1d-restricted lipid presentation and the strategies viruses deploy to subvert this pathway.

  1. 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.

  2. 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.

  3. 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.

  4. Small-angle neutron scattering study of protein crowding in liquid and solid phases: lysozyme in aqueous solution, frozen solution, and carbohydrate powders.

    Science.gov (United States)

    Curtis, Joseph E; Nanda, Hirsh; Khodadadi, Sheila; Cicerone, Marcus; Lee, Hyo Jin; McAuley, Arnold; Krueger, Susan

    2012-08-16

    The structure, interactions, and interprotein configurations of the protein lysozyme were studied in a variety of phases. These properties have been studied under a variety of solution conditions before, during, and after freezing and after freeze-drying in the presence of glucose and trehalose. Contrast variation experiments have also been performed to determine which features of the scattering in the frozen solutions are from the protein and which are from the ice structure. Data from lysozyme at concentrations ranging from 1 to 100 mg/mL in solution and water ice with NaCl concentrations ranging from 0 to 0.4 mol/L are fit to model small-angle neutron scattering (SANS) intensity functions consisting of an ellipsoidal form factor and either a screened-Coulomb or hard-sphere structure factor. Parameters such as protein volume fraction and long dimension are followed as a function of temperature and salt concentration. The SANS results are compared to real space models of concentrated lysozyme solutions at the same volume fractions obtained from Monte Carlo simulations. A cartoon representation of the frozen lysozyme solution in 0 mol/L NaCl is presented based on the SANS and Monte Carlo results, along with those obtained from other complementary methods.

  5. Human Invariant Natural Killer T Cells Respond to Antigen-Presenting Cells Exposed to Lipids from Olea europaea Pollen.

    Science.gov (United States)

    Abos Gracia, Beatriz; López Relaño, Juan; Revilla, Ana; Castro, Lourdes; Villalba, Mayte; Martín Adrados, Beatriz; Regueiro, Jose Ramon; Fernández-Malavé, Edgar; Martínez Naves, Eduardo; Gómez Del Moral, Manuel

    2017-01-01

    Allergic sensitization might be influenced by the lipids present in allergens, which can be recognized by natural killer T (NKT) cells on antigen-presenting cells (APCs). The aim of this study was to analyze the effect of olive pollen lipids in human APCs, including monocytes as well as monocyte-derived macrophages (Mϕ) and dendritic cells (DCs). Lipids were extracted from olive (Olea europaea) pollen grains. Invariant (i)NKT cells, monocytes, Mϕ, and DCs were obtained from buffy coats of healthy blood donors, and their cell phenotype was determined by flow cytometry. iNKT cytotoxicity was measured using a lactate dehydrogenase assay. Gene expression of CD1A and CD1D was performed by RT-PCR, and the production of IL-6, IL-10, IL-12, and TNF-α cytokines by monocytes, Mϕ, and DCs was measured by ELISA. Our results showed that monocytes and monocyte-derived Mϕ treated with olive pollen lipids strongly activate iNKT cells. We observed several phenotypic modifications in the APCs upon exposure to pollen-derived lipids. Both Mϕ and monocytes treated with olive pollen lipids showed an increase in CD1D gene expression, whereas upregulation of cell surface CD1d protein occurred only in Mϕ. Furthermore, DCs differentiated in the presence of human serum enhance their surface CD1d expression when exposed to olive pollen lipids. Finally, olive pollen lipids were able to stimulate the production of IL-6 but downregulated the production of lipopolysaccharide- induced IL-10 by Mϕ. Olive pollen lipids alter the phenotype of monocytes, Mϕ, and DCs, resulting in the activation of NKT cells, which have the potential to influence allergic immune responses. © 2017 S. Karger AG, Basel.

  6. 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.

  7. 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....

  8. 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.

  9. 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...

  10. 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...

  11. 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…

  12. 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...

  13. 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

  14. 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…

  15. 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...

  16. 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...

  17. 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.

  18. 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

  19. 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.

  20. 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

  1. 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

  2. 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.

  3. 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…

  4. 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...

  5. 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.

  6. 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.

  7. [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.

  8. 利用溶菌酶实现SBR系统剩余污泥减量的研究%Study on the effect of excess sludge reduction in SBR by lysozyme

    Institute of Scientific and Technical Information of China (English)

    宋勇; 施周; 陈世洋; 罗璐

    2013-01-01

    为减少SBR系统中剩余污泥的产生量,将溶菌酶作为溶胞剂对SBR系统中的污泥进行水解溶胞.连续50 d运行结果表明,与未添加溶菌酶的对照系统相比,溶菌酶作用下的SBR系统中剩余污泥减量达76.29%;出水COD与NH4+-N的平均质量浓度与对照系统基本持平;50 d内溶菌酶作用下的SBR系统与对照系统的污泥平均蛋白酶活性分别为0.5 U/mg MLSS与0.41 U/mg MLSS.研究表明,溶菌酶作用下的SBR系统对有机污染物具有更强的降解能力.%In the present paper, we would like to introduce a new way to reduce the excessive sludge by using lysozyme in the activated sludge treatment. Our experimental results prove that the lysozyme reaction should be taken as a novel technique to minimize the amount of excess sludge in the sequential batch reactor (SBR). The actual process of the excessive sludge treating is that, first of all, the excessive sludge was taken from a SBR system, and then it was treated by lysozyme reaction and next let it return to the reactor. Since the bacterial cell wall can be effectively hydrolyzed by lysozyme, it can thus be said that it is potentially offering a new approach to reducing the excessive sludge by using lysozyme in the sludge processing. At this point, we have analyzed the quality of the effluent water and the effectiveness of the sludge reduction in the SBR in hoping to determine the effectiveness of the reduction process. The experimental results prove that lysozyme can be used to reduce the production of excessive sludge by 76.29% in the SBR system with lysozyme in the period of a 50-day operation under the comparative and contrast observation in a reference to SBR with no need to add more lysozyme. The average mass concentrations of the effluent chemical oxygen demand and NH4+ - N in the SBR with lysozyme added were almost the same as that in the reference system, which were 53.35 mg/L and 3.71 mg/L respectively. But the average TP removal

  9. Enzymic and immunochemical properties of lysozyme. Accurate definition of the antigenic site around the disulphide bridge 30-115 (site 3) by 'surface-simulation' synthesis.

    Science.gov (United States)

    Lee, C L; Atassi, M Z

    1977-12-01

    1. Previous reports from this laboratory have shown that both Lys-33 and Lys-116 are parts of an antigenic site in native lysozyme. Similar studies of tyrosine derivatives indicated that one or both of Tyr-20 and Tyr-23 are located in or very close to an antigenic site in lysozyme. The site, which was located around the disulphide bridge 30-115, was recently shown unequivocally to include the residues Tyr-20, Arg-21, Lys-116, Asn-113, Arg-114, Phe-34 and Lys-33. This was confirmed by the ;surface-simulation' synthetic approach that we have recently developed, in which the foregoing eight surface residues were directly linked via peptide bonds, with intervening spacers where appropriate, into a single peptide. The peptide does not exist in native lysozyme, but simulates a surface region of it. 2. In the present work several surface-simulation peptides were synthesized representing various parts of the region, to determine the minimum structural feature that retains full antigenic reactivity and to investigate if the spatially constructed antigenic site has a preferred direction. 3. The peptide Lys-Asn-Arg-Gly-Phe-Lys exhibited a remarkable inhibitory activity towards the immune reaction of lysozyme and accounted entirely for the maximum expected reactivity of the site in the native protein (i.e. about one-third of the total lysozyme reactivity). An immunoadsorbent of the peptide bound about one-third of the total antibody to lysozyme. 4. The residues Tyr-20 and Arg-21 are not part of the site. The previously reported immunochemical effect observed on nitration of Tyr-20 was due to a deleterious ionic effect exerted by the modified tyrosine residue on the adjacent Lys-96, which is in an entirely different antigenic site of lysozyme. Thus the modification of Tyr-20 impairs the reactivity of an adjacent antigenic site, even though the residue itself is not part of a site. The conformational and immunochemical implications of this finding are discussed. 5. The antigenic

  10. 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.

  11. 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.

  12. EFFECT OF AQUATIC ENVIRONMENT PH ON THE LEVEL OF ECTOPARASITE INFESTATION, PROTEIN AND LYSOZYME CONTENT IN SOME CYPRINID SPECIES (CYPRINIDAE

    Directory of Open Access Journals (Sweden)

    L. Kurovskaya

    2016-03-01

    Full Text Available Purpose. To study the effect of рН values of the aquatic environment on the level of ectoparasite infestation, protein and lysozyme content in organs and serum of some cyprinid species in experimental conditions. Methodology. The objects of the study were yearlings of Cyprinus carpio, Carassius auratus gibelio and Pseudorasbora parva caught in ponds of fish farm “Nyvka” (Kiev region in spring. Fish were kept in experimental conditions at neutral pH water (6.8-7.2 and a temperature of 17-18оC. To study the changes in the level of fish parasite infestation at different pH values, we used carp yearlings, as an object, the most infected with parasites. Fish were placed in aquariums with water pH of 5.0-5.5 (slightly acidic environment and 8.5-9.0 (slightly alkaline environment for 5 days. Thereafter, the ectoparasites were counted on fish body surface and gills. The protein content in serum and tissue extracts of organs (liver, kidney, spleen of Carassius auratus gibelio and Pseudorasbora parva infected and uninfected ectoparasites, after holding them in slightly acidic or slightly alkaline environment for 8 days, was determined by Lowry’s method, while lysozyme content was determined by a diffusion method on agar. Findings. A comparative assessment of the number of ectoparasites (Ichthyophthirius multifiliis, Trichodina sp., Dactylogyrus sp., Gyrodactylus sp. on fish body surface and gills, the content of protein and lysozyme in serum and organs at different pH values of aquatic environment has been presented. It was demonstrated that the number of ectoparasites on fish body surface and gills was significantly reduced when keeping the fish in both slightly acidic and slightly alkaline environments. In infected Carassius auratus gibelio, a reduction in the protein and lysozyme content in liver, kidney and serum was observed only in the neutral pH environment compared to uninfected individuals. In the slightly acidic or slightly alkaline

  13. 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.

  14. 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).

  15. 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.

  16. 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.

  17. Sarcoidosis Presenting Addison's Disease.

    Science.gov (United States)

    Takahashi, Kentaro; Kagami, Shin-Ichiro; Kawashima, Hirotoshi; Kashiwakuma, Daisuke; Suzuki, Yoshio; Iwamoto, Itsuo

    2016-01-01

    We herein describe a second Japanese case of sarcoidosis presenting Addison's disease. A 52-year-old man was diagnosed with sarcoidosis based on clinical and laboratory findings, including bilateral hilar lymphadenopathy and elevated levels of serum angiotensin-converting enzyme and lysozyme, as well as the presence of noncaseating epithelioid granulomas. The patient also exhibited general fatigue, pigmentation, weight loss, hypotension and hyponatremia, suggestive of chronic adrenocortical insufficiency. An endocrine examination confirmed primary adrenocortical insufficiency. This case suggests the direct involvement of sarcoid granuloma in the adrenal glands.

  18. natural

    Directory of Open Access Journals (Sweden)

    Elías Gómez Macías

    2006-01-01

    Full Text Available Partiendo de óxido de magnesio comercial se preparó una suspensión acuosa, la cual se secó y calcinó para conferirle estabilidad térmica. El material, tanto fresco como usado, se caracterizó mediante DRX, área superficial BET y SEM-EPMA. El catalizador mostró una matriz de MgO tipo periclasa con CaO en la superficie. Las pruebas de actividad catalítica se efectuaron en lecho fijo empacado con partículas obtenidas mediante prensado, trituración y clasificación del material. El flujo de reactivos consistió en mezclas gas natural-aire por debajo del límite inferior de inflamabilidad. Para diferentes flujos y temperaturas de entrada de la mezcla reactiva, se midieron las concentraciones de CH4, CO2 y CO en los gases de combustión con un analizador de gases tipo infrarrojo no dispersivo (NDIR. Para alcanzar conversión total de metano se requirió aumentar la temperatura de entrada al lecho a medida que se incrementó el flujo de gases reaccionantes. Los resultados obtenidos permiten desarrollar un sistema de combustión catalítica de bajo costo con un material térmicamente estable, que promueva la alta eficiencia en la combustión de gas natural y elimine los problemas de estabilidad, seguridad y de impacto ambiental negativo inherentes a los procesos de combustión térmica convencional.

  19. Bovine natural killer cells are present in Escherichia coli infected mammary gland tissue and show antimicrobial activity in vitro

    NARCIS (Netherlands)

    Sipka, Anja; Pomeroy, Brianna; Klaessig, Suzanne; Schukken, Ynte

    2016-01-01

    Natural killer (NK) cells are early responders in bacterial infections but their role in bovine mastitis has not been characterized. For the first time, we show the presence of NK cells (NKp46+/CD3) in bovine mammary gland tissue after an intramammary challenge with Escheri

  20. Between markets and geo-politics : natural resource exploitation on Spitsbergen from 1600 to the present day

    NARCIS (Netherlands)

    Avango, Dag; Hacquebord, Louwrens; Aalders, Ypie; De Haas, Hidde; Gustafsson, Ulf; Kruse, Frigga

    What are the driving forces behind large scale natural resource exploitation in the polar regions and how should we understand the relations between these forces? New historical-archaeological research performed during the International Polar Year (IPY) 2007-2009 on whaling, hunting and mining in

  1. Between markets and geo-politics : natural resource exploitation on Spitsbergen from 1600 to the present day

    NARCIS (Netherlands)

    Avango, Dag; Hacquebord, Louwrens; Aalders, Ypie; De Haas, Hidde; Gustafsson, Ulf; Kruse, Frigga

    2011-01-01

    What are the driving forces behind large scale natural resource exploitation in the polar regions and how should we understand the relations between these forces? New historical-archaeological research performed during the International Polar Year (IPY) 2007-2009 on whaling, hunting and mining in Sp

  2. Social and Rational: The Presentation of Nature of Science and the Uptake of Change in Evolution Textbooks

    Science.gov (United States)

    Fuselier, Linda C.; Jackson, J. Kasi; Stoiko, Rachel

    2016-01-01

    The nature of science (NOS) as described by education scholars is a critical component of scientific literacy and includes both rational and social aspects taught best in an explicit and reflective manner. NOS is frequently tied to a critical contextual empiricism (CCE) framework for knowledge production. Central to CCE is that objectivity is…

  3. 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.

  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. 溶菌酶酶解物的抗菌活性研究%Study on the antibacterial activity of lysozyme hydrolysate

    Institute of Scientific and Technical Information of China (English)

    朱伶俐; 朱明捷; 杨严俊

    2012-01-01

    Objective:Provide the theoretical foundation for broadening the application of lysozyme in food industry through researching on the bacteriostatic ability of Lysozyme hydrolysate. Methods:Lysozyme hydrolysate(LH) was obtained by using pepsin. The antibacterial activity of LH was tested by antibacterial circle experiment; meanwhile,lysozyme and nisin were also tested. The minimum bactericide concentration of LH against common food bacteria was determined with the two-fold dilution method. Results:LH showed great inhibition effect on positive bacteria,especially staphylococcus aureus. Without heat treatment,the bacteriostatic ability of LH on staphylococcus aureus was weaker than lysozyme,but much stronger than nisin. After heat treatment,LH was more antibacterial than lysozyme and nisin. LH was promising to be a natural food preservative.%目的:考察溶菌酶酶解物的抑菌能力.为扩展溶菌酶的应用提供理论依据。方法:采用胃蛋白酶对溶菌酶进行酶解,得到溶菌酶酶解物(Lysozymehydrolysate,LH);采用二倍稀释法检测LH对几种常见食品腐败菌的抑菌能力;以金黄色葡萄球菌为受试菌种,通过抑菌圈实验探讨LH的抑菌活性,并与溶菌酶和乳酸链球菌素作比较。结果:LH对几种常见阳性菌都有很强的抑制作用,其中对金黄色葡萄球菌的抑制作用最强;未经热处理时,LH的抑菌活性略低于溶菌酶,而高于乳酸链球菌素;经热处理后,LH的抑菌活性高于溶菌酶和乳酸链球菌素。菌酶酶解物有望被开发成一种天然的食品防腐剂。

  6. 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.

  7. Present status of vacuum ultraviolet natural circular dichroism measurement system using polarizing undulator at TERAS BL5 beamline

    Energy Technology Data Exchange (ETDEWEB)

    Tanaka, Masahito, E-mail: masahito-tanaka@aist.go.j [Research Institute of Instrumentation Frontier, National Institute of Advanced Industrial Science and Technology (AIST), Central 2, Umezono 1-1-1, Tsukuba, Ibaraki 305-8568 (Japan); Yagi-Watanabe, Kazutoshi; Kaneko, Fusae [Research Institute of Instrumentation Frontier, National Institute of Advanced Industrial Science and Technology (AIST), Central 2, Umezono 1-1-1, Tsukuba, Ibaraki 305-8568 (Japan); Nakagawa, Kazumichi [Graduate School of Human Development and Environment, Kobe University, Tsurukabuto 3-11, Nada-ku, Kobe 657-8501 (Japan)

    2010-08-15

    The study of natural circular dichroism (CD) in the vacuum and extreme ultraviolet (VUV and EUV) regions has been providing us with chirality and structural information on biomolecules. We have developed the beamline BL5 at TERAS, Tsukuba, which is equipped with a compact Onuki-type polarizing undulator. This beamline is dedicated to measuring the CD spectra in the VUV and EUV regions for the photon energy region of 5-40 eV. The use of a polarization modulation technique with a polarizing undulator is essential for detecting a weak CD signal. Using this CD system, the natural CD spectrum has been measured in the EUV region up to 40 eV for the first time. In addition, the differences and the similarities between the CD spectra of four amino acid films (alanine, valine, leucine, and phenylalanine) in the VUV region up to 9.5 eV are determined.

  8. [Radioecology as a branch of natural science: some thoughts on the interesting past, intricate and vital present and future prospects].

    Science.gov (United States)

    Aleksakhin, R M; Prister, B S

    2008-01-01

    The paper describes more than a century-old history of radioecology, science which studies radionuclide migration in the environment and ionizing radiation effects on biota. The main stages are identified in the development of this branch of natural science associated with the study of problems of radioactive contamination of the biosphere (global radionuclide fallout after nuclear weapons tests, radiation accidents with the release of radioactive substances to the environment). Currently, the basic imperative of radioecological investigations is the analysis of radioecological aspects of nuclear power engineering (mainly problems of radioactive waste management). Issues are discussed of radiation protection of biota (environment)--the anthropocentric (sanitary-hygienic) and ecocentric approaches. The importance of radioecology is indicated as the most advanced field of ecology in studying anthropogenic effects on the nature.

  9. Present status of Maconellicoccus hirsutus (Hemiptera: Pseudococcidae) in the Mariana Islands and its control by two fortuitously introduced natural enemies.

    Science.gov (United States)

    Reddy, G V P; Muniappan, R; Cruz, Z T; Naz, F; Bamba, J P; Tenorio, J

    2009-08-01

    The mealybug Maconellicoccus hirsutus (Green) (Hemiptera: Pseudococcidae), attacks ornamental and fruit crops in the Mariana Islands. Insecticides cannot penetrate the heavy layers of wax that protect the insect's body. We surveyed the mealybug's locally recruited natural enemies and their effects on its population on Guam, Rota, Saipan, and Tinian to assess the need for introduction of exotic natural enemies. We monitored population densities of M. hirsutus, those of its natural enemies, and parasitism rates for 3 yr, 2005-2007. Our surveys revealed the presence of two parasitoids, Anagyrus kamali Moursi (Hymenoptera: Encyrtidae) and Allotropa sp. near mecrida (Walker) (Hymenoptera: Platygastridae), fortuitously introduced to the Mariana Islands with M. hirsutus. The predator Cryptolaemus montrouzieri Mulsant (Coleoptera: Coccinellidae) also was often found feeding on M. hirsutus. Population density of M. hirsutus was below the economic threshold at all locations. Rainfall seemed to affect mean numbers of M. hirsutus and mean numbers of eggs at some locations. On all four islands, the two parasitoids, complemented by the predator, were effectively controlling the M. hirsutus population. No evidence of hyperparasitism was recorded. Currently, economic damage by M. hirsutus is not a concern in the Mariana Islands, and additional parasitoids need not be introduced to control M. hirsutus.

  10. 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.

  11. 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.

  12. 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.

  13. A natural language-based presentation of cognitive stimulation to people with dementia in assistive technology: A pilot study.

    Science.gov (United States)

    Dethlefs, Nina; Milders, Maarten; Cuayáhuitl, Heriberto; Al-Salkini, Turkey; Douglas, Lorraine

    2017-01-09

    Currently, an estimated 36 million people worldwide are affected by Alzheimer's disease or related dementias. In the absence of a cure, non-pharmacological interventions, such as cognitive stimulation, which slow down the rate of deterioration can benefit people with dementia and their caregivers. Such interventions have shown to improve well-being and slow down the rate of cognitive decline. It has further been shown that cognitive stimulation in interaction with a computer is as effective as with a human. However, the need to operate a computer often represents a difficulty for the elderly and stands in the way of widespread adoption. A possible solution to this obstacle is to provide a spoken natural language interface that allows people with dementia to interact with the cognitive stimulation software in the same way as they would interact with a human caregiver. This makes the assistive technology accessible to users regardless of their technical skills and provides a fully intuitive user experience. This article describes a pilot study that evaluated the feasibility of computer-based cognitive stimulation through a spoken natural language interface. Prototype software was evaluated with 23 users, including healthy elderly people and people with dementia. Feedback was overwhelmingly positive.

  14. Dramatic Changes of Matrix Metalloproteinases-7 and Lysozyme in the Ulcerative Colitis of Mice Induced by Dextran Sulfate Sodium

    Institute of Scientific and Technical Information of China (English)

    KANG Jing-jing; YANG Yu-rong; LIANG Hong-de; ZHAO De-ming; TENG Ke-dao; JIAO Xi-lan; WANG Ping-li; SUN Zhe; NI Pei-pei; WANG Zhi-feng; ZHANG Rui

    2014-01-01

    Ulcerative colitis (UC) is a lifelong illness with profound emotional and social impacts, and could cause serious damage to large intestine, especially in colon. However, the pathogenesis of UC remained unclear. The present study attempts to ifnd out the role of matrix metalloproteinases-7 (MMP-7) and lysozyme in the pathogenesis of UC through a mice model induced by dextran sulfate sodium (DSS). The UC model was evaluated both by disease activity index (DAI) and the intestinal histopathology. The results show that there is a high correlation between the DAI score and the pathological changes of colon. Interleukin-6 (IL-6) serum levels and large intestinal lfuids levels in UC mice are always higher than that of the control groups, which might be associated with the degree of the inlfammation damage in the colon. The change tendency of the MMP-7 mRNA and protein expressions are both up-regulated ifrstly and then down-regulated from 1 to 5 d in the colon, but only the MMP-7 protein is up-regulated at 7 d again. The up-regulated MMP-7 levels in the early stage of UC may play a protective role through the activated defensins, while the down-regulated levels in the mid-later stage of UC may be connected with the severe lesions in the colon. However, the up-regulated MMP-7 levels in the later stage of UC in the colon may also contribute to the tissue repair or be served as a marker to CRC (colorectal cancer). The distribution of lysozyme protein indicates that there may be Paneth-like cells in the colon. Both the changes of MMP-7 and lysozyme in the small intestine may play a protective role for the safe environment of the whole gut, especially to the colon of UC.

  15. Two-dimensional fluorescence correlation spectroscopy IV: Resolution of fluorescence of tryptophan residues in alcohol dehydrogenase and lysozyme

    Science.gov (United States)

    Fukuma, Hiroaki; Nakashima, Kenichi; Ozaki, Yukihiro; Noda, Isao

    2006-11-01

    Generalized two-dimensional (2D) fluorescence correlation spectroscopy has been used to resolve the fluorescence spectra of two tryptophan (Trp) residues in alcohol dehydrogenase and lysozyme. In each protein, one Trp residue is buried in a hydrophobic domain of the protein matrix and the other Trp residue is located at a hydrophilic domain close to the protein-water interface. Fluorescence quenching by iodide ion, a hydrophilic quencher, was employed as a perturbation to induce the intensity change in the spectra. The Trp residue which is located at the hydrophilic domain is effectively quenched by the quencher, while the Trp residue located at the hydrophobic domain is protected from the quenching. Therefore, the fluorescence of these two Trp residues have a different sensitivity to the quenching, showing a different response to the concentration of the quencher. Fluorescence spectra of the two Trp residues in alcohol dehydrogenase, which are heavily overlapped in conventional one-dimensional spectra, have been successfully resolved by the 2D correlation technique. From the asynchronous correlation map, it was revealed that the quenching of Trp located at the hydrophobic part was brought about after that of Trp located at the hydrophilic part. In contrast, the fluorescence spectra of the two Trp residues could not be resolved after the alcohol dehydrogenase was denatured with guanidine hydrochloride. These results are consistent with the well-known structure of alcohol dehydrogenase. Furthermore, it was elucidated that the present 2D analysis is not interfered by Raman bands of the solvent, which sometimes bring difficulty into the conventional fluorescence analysis. Fluorescence spectra of the Trp residues in lysozyme could not be resolved by the 2D correlation technique. The differences between the two proteins are attributed to the fact that the Trp residue in the hydrophobic site of lysozyme is not sufficiently protected from the quenching.

  16. The natural history of medium-chain acyl CoA dehydrogenase deficiency in the Netherlands : Clinical presentation and outcome

    NARCIS (Netherlands)

    Derks, Terry G J; Reijngoud, Dirk-Jan; Waterham, Hans R; Gerver, Willem-Jan M; van den Berg, Maarten P; Sauer, Pieter J J; Smit, G Peter A

    2006-01-01

    OBJECTIVES: To describe the clinical presentation and long-term follow-up of a large cohort of patients with medium-chain acyl-CoA dehydrogenase (MCAD) deficiency. STUDY DESIGN: A nationwide, retrospective analysis of clinical presentation and follow-up in 155 Dutch patients with MCAD deficiency. RE

  17. Timing and nature of presentation of unsuspected retained common bile duct stones after laparoscopic cholecystectomy: a retrospective study.

    Science.gov (United States)

    Cox, Michael R; Budge, Joel P O; Eslick, Guy D

    2015-07-01

    Common bile duct (CBD) stones may be over looked at the time of laparoscopic cholecystectomy (LC), particularly when intra-operative cholangiography (IOC) is not performed. Currently, there is no data available about the time course and pattern of presentation for stones retained in the CBD at the time of LC. The aim of this study was to establish the time course and pattern of presentation of unsuspected retained CBD stones post LC. Patients presenting with symptomatic CBD stones from 1994 until 2010, having previously undergone LC were studied in this retrospective, case note review. CBD stones were confirmed at ERCP. Data collected included LC date, mode of presentation, imaging results including CBD diameter, stone appearance, length of stay and post ERCP complications. Patients having an ERCP for stones found on IOC at LC were excluded. Sixty-one patients met the inclusion criteria. The most common mode of presentation was abdominal pain (n = 38, 62%) with (17) or without (21) deranged liver function tests. Nineteen (31%) patients presented with clinical complications of the CBD stones: cholangitis (10), acute biliary pancreatitis (6) or obstructive jaundice (3). The CBD was usually mild-to-moderately dilated (8-15 mm) on ultrasound. The median time span from LC to presentation with CBD stones was 4 years (range: 6 days-18 years). Five (8.2%) patients had a complication from their ERCP; mild pancreatitis (3), bleed (1) and cholangitis (1). Nineteen (31.1%) patients required more than one ERCP to complete stone/stent removal. The median time for patients to present with symptomatic CBD stones after LC is 4 years. Patients with retrained stones may remain asymptomatic for many years. A third of the patients presented with potentially serious complications of the retained CBD stone. Future studies for CBD stones after LC need to follow patients for at least 10 years.

  18. Bovine natural killer cells are present in Escherichia coli infected mammary gland tissue and show antimicrobial activity in vitro.

    Science.gov (United States)

    Sipka, Anja; Pomeroy, Brianna; Klaessig, Suzanne; Schukken, Ynte

    2016-10-01

    Natural killer (NK) cells are early responders in bacterial infections but their role in bovine mastitis has not been characterized. For the first time, we show the presence of NK cells (NKp46(+)/CD3(-)) in bovine mammary gland tissue after an intramammary challenge with Escherichia (E.) coli. A small number of NK cells was detected in milk from quarters before and during an E. coli challenge. In vitro cultures of primary bovine mammary gland epithelial cells stimulated with UV irradiated E. coli induced significant migration of peripheral blood NK cells (pbNK) within 2h. Furthermore, pbNK cells significantly reduced counts of live E. coli in vitro within 2h of culture. The results show that bovine NK cells have the capacity to migrate to the site of infection and produce antibacterial mediators. These findings introduce NK cells as a leukocyte population in the mammary gland with potential functions in the innate immune response in bovine mastitis.

  19. 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.

  20. 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.

  1. 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.

  2. 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...

  3. 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.

  4. 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.

  5. 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.

  6. Subject Indicators to Present the Nature and Limit of Environmental Studies in U.S. Graduate Schools.

    Science.gov (United States)

    Kim, H. S.; Dixon, James P.

    1993-01-01

    Examines the lack of interdisciplinary communication in environmental education programs in U.S. graduate schools. Following comparative historical reviews of environmental protection activities, presents a computer-developed curriculum model base containing 15 subject areas: philosophy, politics, economics, architecture, sociology, biology,…

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. Development of a rubber elongation factor, surface-imprinted polymer-quartz crystal microbalance sensor, for quantitative determination of Hev b1 rubber latex allergens present in natural rubber latex products.

    Science.gov (United States)

    Sontimuang, Chonlatid; Suedee, Roongnapa; Canyuk, Bhutorn; Phadoongsombut, Narubodee; Dickert, Franz L

    2011-02-21

    Molecularly imprinted polymers (MIPs) for screening to detect rubber latex allergens (Hev b1) in natural rubber based products were designed as artificial recognition polymeric materials coated onto a quartz crystal microbalance (QCM). The polymers were prepared using a stamp imprinting procedure after mixing optimum amounts of methacrylic acid-vinylpyrrolidone-dihydroxyethylene bisacrylamide and Hev b1 latex allergen proteins, obtained from rubber gloves. QCM measurements showed that the resulting polymer layers after removal of the proteins used in their preparation could incorporate structures and features down to nanometer scale of protein templates into the imprinted polymer much better than a non-specific control polymer under controlled sensor conditions and an optimized polymerization process. This selective polymer but not the non-selective polymer clearly distinguished between the latex allergen Hev b1 and proteins such as lysozyme, ovalbumin and bovine serum albumin, with a selectivity factor of from 2 to 4, and the response of the rubber elongation factors by an astonishing factor of 12. The imprinted cavities recognized specific binding sites and could distinguish among related hevein latex allergenic proteins isolated from fresh natural rubber latex; Hev b1, Hev b2, and Hev b3 with a selectivity factor of from 4 to 6. The different QCM measurements obtained presumably reflected slightly different conformations and affinities to the MIP binding sites. The sensor layers selectively adsorbed Hev b1 within minutes in amounts ranging from 10 to 1500 μg L⁻¹ and with a detection limit of 1 μg L⁻¹. This work has demonstrated that this new sensor provides a fast and reliable response to natural rubber latex protein, even after being extracted from the matrix of rubber gloves.

  14. Crystal growth in a three-phase system: diffusion and liquid-liquid phase separation in lysozyme crystal growth.

    Science.gov (United States)

    Heijna, M C R; van Enckevort, W J P; Vlieg, E

    2007-07-01

    In the phase diagram of the protein hen egg-white lysozyme, a region is present in which the lysozyme solution demixes and forms two liquid phases. In situ observations by optical microscopy show that the dense liquid droplets dissolve when crystals grow in this system. During this process the demixed liquid region retracts from the crystal surface. The spatial distribution of the dense phase droplets present special boundary conditions for Fick's second law for diffusion. In combination with the cylindrical symmetry provided by the kinetically roughened crystals, this system allows for a full numerical analysis. Using experimental data for setting the boundary conditions, a quasi-steady-state solution for the time-dependent concentration profile was shown to be valid. Comparison of kinetically rough growth in a phase separated system and in a nonseparated system shows that the growth kinetics for a three-phase system differs from a two-phase system, in that crystals grow more slowly but the duration of growth is prolonged.

  15. Intramammary expression and therapeutic effect of a human lysozyme-expressing vector for treating bovine mastitis

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    To develop a gene therapy strategy for treating bovine mastitis, a new mammary-specific vector containing human lysozyme (hLYZ) cDNA and kanamycin resistance gene was constructed for intramammary expression and clinical studies. After one time acupuncture or intracisternal infusion of healthy cows with 400 μg of the p215C3LYZ vector, over 2.0 μg/ml of rhLYZ could be detected by enzymatic assay for about 3 weeks in the milk samples. Western blotting showed that rhLYZ secreted into milk samples from the vector-injected cows had molecular weight similar to that of the natural hLYZ in human colostrums.Twenty days after the primary injection, the quarters were re-injected with the same vector by quarter acupuncture and even higher concentrations of rhLYZ could be detected. Indirect competitive ELISA of milk samples showed that the vector injection did not induce detectable humoral immune response against hLYZ. Clinical studies showed that twice acupuncture of quarters with the p215C3LYZ vector had overt therapeutic effect on clinical and subclinical mastitis previously treated with antibiotics, including disappearance of clinical symptoms and relatively high microbiological cure rates. These data provide a solid rationale for using the vector to develop gene therapy for treating bovine mastitis.

  16. In vitro chondrogenesis with lysozyme susceptible bacterial cellulose as a scaffold.

    Science.gov (United States)

    Yadav, Vikas; Sun, Lin; Panilaitis, Bruce; Kaplan, David L

    2015-12-01

    A current focus of tissue engineering is the use of adult human mesenchymal stem cells (hMSCs) as an alternative to autologous chondrocytes for cartilage repair. Several natural and synthetic polymers (including cellulose) have been explored as a biomaterial scaffold for cartilage tissue engineering. While bacterial cellulose (BC) has been used in tissue engineering, its lack of degradability in vivo and high crystallinity restricts widespread applications in the field. Recently we reported the formation of a novel bacterial cellulose that is lysozyme-susceptible and -degradable in vivo from metabolically engineered Gluconacetobacter xylinus. Here we report the use of this modified bacterial cellulose (MBC) for cartilage tissue engineering using hMSCs. MBC's glucosaminoglycan-like chemistry, combined with in vivo degradability, suggested opportunities to exploit this novel polymer in cartilage tissue engineering. We have observed that, like BC, MBC scaffolds support cell attachment and proliferation. Chondrogenesis of hMSCs in the MBC scaffolds was demonstrated by real-time RT-PCR analysis for cartilage-specific extracellular matrix (ECM) markers (collagen type II, aggrecan and SOX9) as well as histological and immunohistochemical evaluations of cartilage-specific ECM markers. Further, the attachment, proliferation, and differentiation of hMSCs in MBC showed unique characteristics. For example, after 4 weeks of cultivation, the spatial cell arrangement and collagen type-II and ACAN distribution resembled those in native articular cartilage tissue, suggesting promise for these novel in vivo degradable scaffolds for chondrogenesis.

  17. Past agricultural land use and present-day fire regimes can interact to determine the nature of seed predation.

    Science.gov (United States)

    Stuhler, John D; Orrock, John L

    2016-06-01

    Historical agriculture and present-day fire regimes can have significant effects on contemporary ecosystems. Although past agricultural land use can lead to long-term changes in plant communities, it remains unclear whether these persistent land-use legacies alter plant-consumer interactions, such as seed predation, and whether contemporary disturbance (e.g., fire) alters the effects of historical agriculture on these interactions. We conducted a study at 27 sites distributed across 80,300 ha in post-agricultural and non-agricultural longleaf pine woodlands with different degrees of fire frequency to test the hypothesis that past and present-day disturbances that alter plant communities can subsequently alter seed predation. We quantified seed removal by arthropods and rodents for Tephrosia virginiana and Vernonia angustifolia, species of conservation interest. We found that the effects of land-use history and fire frequency on seed removal were contingent on granivore guild and microhabitat characteristics. Tephrosia virginiana removal was greater in low fire frequency sites, due to greater seed removal by rodents. Although overall removal of V. angustifolia did not differ among habitats, rodents removed more seeds than arthropods at post-agricultural sites and non-agricultural sites with low fire frequencies, but not at non-agricultural sites with high fire frequencies. Land-use history and fire frequency also affected the relationship between microhabitat characteristics and removal of V. angustifolia. Our results suggest that historical agriculture and present-day fire regimes may alter seed predation by shifting the impact of rodent and arthropod seed predators among habitats, with potential consequences for the establishment of rare plant species consumed by one or both predators.

  18. 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.

  19. Absent yet Present: On the Paradoxical Nature of Characters in Nabokov’s The Real Life of Sebastian Knight

    Directory of Open Access Journals (Sweden)

    Irina Marchesini

    2016-11-01

    Full Text Available The present research is focused on the theme of absence, an area of inquiry that might seem dominant in the field of Nabokov Studies. The analysis, which concentrates in particular on the key figures of the novel The Real Life of Sebastian Knight (1941, notably the narrator V. and the poet Sebastian Knight, interprets the characters’ construction through the paradigm of absence. Arguably, the construction of characters in The Real Life of Sebastian Knight is paradoxical: absence constitutes their essence at a core level, as it often happens in the context of the self-conscious genre. Moreover, absence plays a key role in characters’ design, linking them to all Nabokovian novels. However, despite their innermost ‘flatness’, to use Edward M. Forster’s terminology, they still appear to be ‘round’, i.e. plausible, mimetic figures.

  20. Present geotemperature and its suggestion to natural gas generation in Xujiaweizi fault-depression of the northern Songliao Basin

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    According to stastistic of present geotemperatures at the depths of 1000,2000,3000 and 4000 m,respectively in the Xujiaweizi fault-depression of the north Songliao Basin,the result indicates that Xujiaweizi fault-depression falls in the high geotemperature area,with the higher geothermal gradient in the depression layer than that in the fault-depression layer.The geothermal gradient decreases with the increasing of the depth.The thermal conductivity of rock greatly controls the geothermal gradient.The main factors constraining the current geotemperature include thermal configuration of the earth’s crust, deep faults,distribution and abundance of radioelements.The high geotemperature is in favour of generation of deep gas.

  1. Natural language query system design for interactive information storage and retrieval systems. Presentation visuals. M.S. Thesis Final Report, 1 Jul. 1985 - 31 Dec. 1987

    Science.gov (United States)

    Dominick, Wayne D. (Editor); Liu, I-Hsiung

    1985-01-01

    This Working Paper Series entry represents a collection of presentation visuals associated with the companion report entitled Natural Language Query System Design for Interactive Information Storage and Retrieval Systems, USL/DBMS NASA/RECON Working Paper Series report number DBMS.NASA/RECON-17.

  2. 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.

  3. Biological inspiration in optics and photonics: harnessing nature's light manipulation strategies for multifunctional optical materials (Conference Presentation)

    Science.gov (United States)

    Kolle, Mathias; Sandt, Joseph D.; Nagelberg, Sara N.; Zarzar, Lauren D.; Kreysing, Moritz; Vukusic, Peter

    2016-03-01

    lie at the origin of many species' ability to grow photonic materials will also be presented.

  4. 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.

  5. [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.

  6. 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.

  7. 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.

  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. Severe clinical presentation of visceral leishmaniasis in naturally infected dogs with disruption of the splenic white pulp.

    Directory of Open Access Journals (Sweden)

    Isadora S Lima

    Full Text Available In this work, we investigated the association between the disruption of splenic lymphoid tissue and the severity of visceral leishmaniasis in dogs. Clinical and laboratory data from 206 dogs were reviewed. Spleen sections collected during the euthanasia of these animals were analyzed, and the splenic lymphoid tissue samples were classified as well organized (spleen type 1, slightly disorganized (spleen type 2, or moderately to extensively disorganized (spleen type 3. Of 199 dogs with evidence of Leishmania infection, 54 (27% had spleen type 1, 99 (50% had spleen type 2, and 46 (23% had spleen type 3. The number of clinical signs associated with visceral leishmaniasis was significantly higher in the animals with evidence of Leishmania infection and spleen type 2 or 3 than in the animals with spleen type 1. Alopecia, anemia, dehydration, dermatitis, lymphadenopathy, and onychogryphosis were all more frequent among animals with evidence of Leishmania infection and spleen type 3 than among the dogs with evidence of Leishmania infection and spleen type 1. The association between the severity of canine visceral leishmaniasis and the disorganization of the splenic lymphoid tissue was even more evident in the group of animals with positive spleen culture. Conjunctivitis and ulceration were also more common in the animals with spleen type 3 than in the animals with spleen type 1. The serum levels (median, interquartile range of albumin (1.8, 1.4-2.3 g/dL and creatinine (0.7, 0.4-0.8 mg/dL were significantly lower and the serum levels of aspartate aminotransferase were significantly higher (57, 39-95 U in animals with spleen type 3 than in animals with spleen type 1 (2.8, 2.4-3.4 g/dL; 0.9, 0.7-1.2 mg/dL and 23, 20-32 U, respectively. Our data confirm the hypothesis that disruption of the splenic lymphoid tissue is associated with a more severe clinical presentation of canine visceral leishmaniasis.

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. Enterococcus faecalis zinc-responsive proteins mediate bacterial defence against zinc overload, lysozyme and oxidative stress.

    Science.gov (United States)

    Abrantes, Marta C; Kok, Jan; Silva Lopes, Maria de Fátima

    2014-12-01

    Two Enterococcus faecalis genes encoding the P-type ATPase EF1400 and the putative SapB protein EF0759 were previously shown to be strongly upregulated in the presence of high concentrations of zinc. In the present work, we showed that a Zn(2+)-responsive DNA-binding motif (zim) is present in the promoter regions of these genes. Both proteins were further studied with respect to their involvement in zinc homeostasis and invasion of the host. EF0759 contributed to intramacrophage survival by an as-yet unknown mechanism(s). EF1400, here renamed ZntAEf, is an ATPase with specificity for zinc and plays a role in dealing with several host defences, i.e. zinc overload, oxidative stress and lysozyme; it provides E. faecalis cells with the ability to survive inside macrophages. As these three host defence mechanisms are important at several sites in the host, i.e. inside macrophages and in saliva, this work suggested that ZntAEf constitutes a crucial E. faecalis defence mechanism that is likely to contribute to the ability of this bacterium to endure life inside its host.

  16. Temperature dependence of lysozyme hydration and the role of elastic energy

    Science.gov (United States)

    Wang, Hai-Jing; Kleinhammes, Alfred; Tang, Pei; Xu, Yan; Wu, Yue

    2011-03-01

    Water plays a critical role in protein dynamics and functions. However, the most basic property of hydration—the water sorption isotherm—remains inadequately understood. Surface adsorption is the commonly adopted picture of hydration. Since it does not account for changes in the conformational entropy of proteins, it is difficult to explain why protein dynamics and activity change upon hydration. The solution picture of hydration provides an alternative approach to describe the thermodynamics of hydration. Here, the flexibility of proteins could influence the hydration level through the change of elastic energy upon hydration. Using nuclear magnetic resonance to measure the isotherms of lysozyme in situ between 18 and 2 °C, the present work provides evidence that the part of water uptake associated with the onset of protein function is significantly reduced below 8 °C. Quantitative analysis shows that such reduction is directly related to the reduction of protein flexibility and enhanced cost in elastic energy upon hydration at lower temperature. The elastic property derived from the water isotherm agrees with direct mechanical measurements, providing independent support for the solution model. This result also implies that water adsorption at charged and polar groups occurring at low vapor pressure, which is known for softening the protein, is crucial for the later stage of water uptake, leading to the activation of protein dynamics. The present work sheds light on the mutual influence of protein flexibility and hydration, providing the basis for understanding the role of hydration on protein dynamics.

  17. 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.

  18. 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

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. 溶菌酶在酱油中的抑菌效果研究%Studies of lysozyme on the inhibiting efficiency of the microorganisms in soy sauce

    Institute of Scientific and Technical Information of China (English)

    范蕴莹

    2012-01-01

    Lysozyme is a protein molecule that is comprised of a polypeptide chain. It has good thermal stability in the acid solutions, and words well in killing Gram - positive bacteria. So it is a better and natural preservative than the others which is used in soy sauce. The effect of lysozyme on inhibiting microorganisms in soy sauce was studied in this research. The results showed that; (1) the best dosage of lysozyme was 150 mg/kg in soy sauce, which could inhibite microorganisms well, and kill the microorganisms slowly. Then the antiseptic effect of lysozyme was better 0. 1% sodium benzoate. (2) Lysozyme worked better in the soy sauce that has high salt content than the low one, and the total plate count of the soy sauce decreased much more obviously. (3) Pasteurisation affected the lysozyme activity little. (4) Lysozyme inhibited microorganisms well in soy sauce, in which the total plate count was no more than 10000cfu/ml. and increased slowly. The product quality of soy sauce was stable during the shelf - life.%溶菌酶为多肽链组成的蛋白质分子,酶活在酸性条件下具有良好的热稳定性,且对革兰氏阳性细菌具有专一的抑制杀灭作用,是成品酱油的一种良好的天然抑菌防腐剂.本文研究了溶菌酶在酱油中的抑菌防腐效果.结果表明:(1)在酱油中,溶菌酶的抑菌防腐效果理想,且具有缓慢杀菌的功能,其最佳添加量为150 mg/kg,抑菌防腐效果比0.1%苯甲酸钠要好;(2)在高盐分含量酱油中的抑菌防腐效果比低盐分含量酱油要好,添加溶菌酶后菌落总数下降趋势更加明显;(3)酱油的巴氏灭菌操作对溶菌酶的活性无显著影响;(4)在起始菌落总数为10000 cfu/ml或以下的酱油中使用溶菌酶能使酱油具有较好的抑菌防腐效果,在货架期内菌落总数增长缓慢,产品质量稳定.

  7. Preparation of cross-linked hen-egg white lysozyme crystals free of cracks

    Science.gov (United States)

    Yan, Er-Kai; Lu, Qin-Qin; Zhang, Chen-Yan; Liu, Ya-Li; He, Jin; Chen, Da; Wang, Bo; Zhou, Ren-Bin; Wu, Ping; Yin, Da-Chuan

    2016-01-01

    Cross-linked protein crystals (CLPCs) are very useful materials in applications such as biosensors, catalysis, and X-ray crystallography. Hence, preparation of CLPCs is an important research direction. During the preparation of CLPCs, an often encountered problem is that cracks may appear in the crystals, which may finally lead to shattering of the crystals into small pieces and cause problem in practical applications. To avoid cross-link induced cracking, it is necessary to study the cracking phenomenon in the preparation process. In this paper, we present an investigation on how to avoid cracking during preparation of CLPCs. An orthogonal experiment was designed to study the phenomenon of cross-link induced cracking of hen-egg white lysozyme (HEWL) crystals against five parameters (temperature, solution pH, crystal growth time, glutaraldehyde concentration, and cross-linking time). The experimental results showed that, the solution pH and crystal growth time can significantly affect cross-link induced cracking. The possible mechanism was studied, and optimized conditions for obtaining crack-free CLPCs were obtained and experimentally verified. PMID:27703210

  8. Relaxation dynamics of lysozyme in solution under pressure: Combining molecular dynamics simulations and quasielastic neutron scattering

    Energy Technology Data Exchange (ETDEWEB)

    Calandrini, V. [Centre de Biophysique Moleculaire, Rue Charles Sadron, 45071 Orleans (France); Synchrotron Soleil, L' Orme de Merisiers, B.P. 48, 91192 Gif-sur-Yvette (France); Hamon, V. [Centre de Biophysique Moleculaire, Rue Charles Sadron, 45071 Orleans (France); Hinsen, K. [Centre de Biophysique Moleculaire, Rue Charles Sadron, 45071 Orleans (France); Synchrotron Soleil, L' Orme de Merisiers, B.P. 48, 91192 Gif-sur-Yvette (France); Calligari, P. [Centre de Biophysique Moleculaire, Rue Charles Sadron, 45071 Orleans (France); Institut Laue-Langevin, 6 Rue Jules Horowitz, B.P. 156, 38042 Grenoble (France); Laboratoire Leon Brillouin, CEA Saclay, 91191 Gif-sur-Yvette (France); Bellissent-Funel, M.-C. [Laboratoire Leon Brillouin, CEA Saclay, 91191 Gif-sur-Yvette (France); Kneller, G.R. [Centre de Biophysique Moleculaire, Rue Charles Sadron, 45071 Orleans (France); Synchrotron Soleil, L' Orme de Merisiers, B.P. 48, 91192 Gif-sur-Yvette (France)], E-mail: kneller@cnrs-orleans.fr

    2008-04-18

    This paper presents a study of the influence of non-denaturing hydrostatic pressure on the relaxation dynamics of lysozyme in solution, which combines molecular dynamics simulations and quasielastic neutron scattering experiments. We compare results obtained at ambient pressure and at 3 kbar. Experiments have been performed at pD 4.6 and at a protein concentration of 60 mg/ml. For both pressures we checked the monodispersity of the protein solution by small angle neutron scattering. To interpret the simulation results and the experimental data, we adopt the fractional Ornstein-Uhlenbeck process as a model for the internal relaxation dynamics of the protein. On the experimental side, global protein motions are accounted for by the model of free translational diffusion, neglecting the much slower rotational diffusion. We find that the protein dynamics in the observed time window from about 1 to 100 ps is slowed down under pressure, while its fractal characteristics is preserved, and that the amplitudes of the motions are reduced by about 20%. The slowing down of the relaxation is reduced with increasing q-values, where more localized motions are seen.

  9. Interactions of cytotoxic amino acid derivatives of tert-butylquinone with DNA lysozyme

    Directory of Open Access Journals (Sweden)

    Vilipić Jovana P.

    2016-01-01

    Full Text Available The interactions of nine amino acid derivatives of tert-butylquinone with biomacromolecules were studied. SDS electrophoresis and mass spectrometry confirmed the absence of modifications of lysozyme by any of the synthesized compounds. Spectrophotometric studies demonstrated hyperchromism, i.e. existence of interactions between the quinones and CT-DNA. Determination of binding constant by absorption titration indicates weak interactions between quinone derivatives and CT-DNA. The quenching of fluorescence of intercalator ethidium bromide from EB-CT-DNA system and of minor groove binder Hoechst 33258 from H-CT-DNA system by the synthesized derivatives indicates interactions of compounds and CT-DNA. CD spectra demonstrate non-intercalative binding mode of quinone derivaties to CT-DNA. Molecular docking results confirm binding to the minor groove. Electrophoretic pattern showed no cleavage of pUC19 plasmid in the presence of any of the synthesized compounds. The ability of the derivatives to scavenge radicals was confirmed by DPPH test. All the presented results suggest that the DNA minor groove binding is the principal mechanism of action of the examined amino acid derivatives. [Projekat Ministarstva nauke Republike Srbije, br. 172055

  10. Synthesis Optimisation of Lysozyme Monolayer-Coated Silver Nanoparticles in Aqueous Solution

    Directory of Open Access Journals (Sweden)

    A. V. Yakovlev

    2014-01-01

    Full Text Available This paper presents an optimisation of the synthesis of silver nanoparticles encapsulated in a biological shell. The synthesis was carried out in an aqueous solution of silver nitrate. Sodium borohydride was used as a reducing agent. Lysozyme served as a bioactive coating agent. The samples produced were studied using dynamic light scattering, transmission electron microscopy, and UV-Vis spectroscopy. The function of the dependence of the reagent ratio in obtained sols on optical properties is shown. Furthermore, the influence of the synthesis temperature, reactant ratio, and order of mixing on the particle size distribution parameters is shown. The optimal reagent mass ratio, NaBH4 : LYZ : AgNO3 = 0.22 : 0.77 : 1, is established. The resulting composition allows the synthesis of particles with a mean diameter of 18 nm and a bioshell thickness of ≈3.5 nm. Moreover, the necessity of the synthesis optimisation and precise parameter control is clearly demonstrated.

  11. Inhibitory effect of copper nanoparticles on rosin modified surfactant induced aggregation of lysozyme.

    Science.gov (United States)

    Ishtikhar, Mohd; Usmani, Salman Sadullah; Gull, Nuzhat; Badr, Gamal; Mahmoud, Mohamed H; Khan, Rizwan Hasan

    2015-01-01

    Protein aggregation is associated with many serious diseases including Parkinson's and Alzheimer's. Protein aggregation is a primary problem related with the health of industrial workers who work with the surfactants, metal ions, and cosolvents. We have synthesized rosin-based surfactants, i.e., quaternary amines of rosin diethylaminoethyl esters (QRMAE), which is an ester of rosin acid with polyethylene glycol monomethyl ether. Here, we report the thermal aggregation of lysozyme induced by QRMAE at 65 °C and pH 7.4 for a given time period in which amorphous aggregates are formed and confirm that copper-nanoparticles have the ability to inhibit QRMAE-induced aggregation compared with zinc and silver-nanoparticles. Aggregation experiments was evaluated using several spectroscopic methods and dye binding assay, such as turbidity, Rayleigh light scattering, 1-anilino-8-naphthalene sulfonate (ANS), Thioflavin T (Th T), congo red (CR) and circular dichroism (CD), that was further supported by scanning electron microscopy (SEM) and SEM with EDX. The therapeutic use of nanoparticles and the fact that rosin possesses excellent film-forming properties, and that its derivatives have pharmaceuticals application such as micro encapsulation, coating and film forming, it's matrix materials are used for sustained and controlled release tablets, renders importance and application to the present study.

  12. 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.

  13. 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.

  14. 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.

  15. 牛乳溶菌酶概述及应用%Overview and Applications of Bovine lysozyme

    Institute of Scientific and Technical Information of China (English)

    张璐莹; 聂甜甜; 郑程远; 付世新

    2012-01-01

    Lysozyme, also known as murarnidase. Widespread in nature, animals, plants and microorganisms.Has antibac- terial anti-inflammatory, anti-viral, and enhance the immune system and promote tissue repair and other biological charac- teristics. And used in food, fodder, medicine and bioengineering. For current clinical mastitis in dairy cows widely exten- sive use of antibiotics, and there is the phenomenon of drug resistance, drug residues. The recombinant lysozyme plasmid genetically engineered drugs can be used as alternative to antibiotics for mastitis prevention and control, and security, no residue, no side effects. Also needs further development and promotion.%溶菌酶又称胞壁质酶,广泛存在于自然界的动物、植物及微生物中。具有抗菌消炎、抗病毒、增强免疫力以及促进组织修复等生物学特性。并且应用于食品、饲料、医学及生物工程之中。针对目前临床中,对于奶牛乳房炎广泛大量使用抗生素,并且存在耐药性、药物残留等现象。重组溶菌酶质粒可以作为基因工程药物替代抗生素对乳房炎的防治,并且安全、无残留、无副作用。同时也还有待于进一步的研发和推广。

  16. Differential major histocompatibility complex-related activation of idiotypic suppressor T cells. Suppressor T cells cross-reactive to two distantly related lysozymes are not induced by one of them.

    Science.gov (United States)

    Adorini, L; Harvey, M A; Rozycka-Jackson, D; Miller, A; Sercarz, E E

    1980-09-01

    B10 (H-2b) mice are genetic nonresponders to hen egg-white lysozyme (HEL) and the distantly related human lysozyme (HUL). However, anti-HEL or anti-HUL primary antibody responses in vivo or in vitro can be obtained in B10 mice by immunization with the appropriate lysozyme coupled to erythrocytes. T cells able to suppress either anti-lysozyme plaque-forming cells (PFC) response are induced in B10 mice after immunization with HEL-complete Freund's adjuvant (CFA) or HUL-CFA. This cross-reactivity of HEL and HUL in the induction and the expression of suppressive activity is in marked contrast to their very low cross-reactivity at the PFC level. These results suggest that either HEL or HUL can stimulate a suppressor T cell which recognizes a particular epitope present on both lysozymes. Suppressor cells induced by HEL or HUL bear the same predominant idiotype found on the majority of anti-HEL antibodies, and on the small proportion of anti-HUL antibodies cross-reactive with HEL. B10.Q (H-2q) mice are responders in vivo to HEL-CFA, but not to HUL-CFA. In contrast to B10, HEL-CFA priming in B10.Q micr induces helper cells whereas HUL-CFA priming induces suppressor cells. These suppressor cells are cross-reactive with HEL and are fully able to suppress HEL-specific helper cells. The presence of HEL-specific suppressor cell precursors in B10.Q mice which are not activated by HEL, seems to implicate differential choice by the antigen presenting system as a basis for Ir gene control, rather than the absence of a regulatory cell type from the T cell repertoire.

  17. 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.

  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. 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.

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. Direct observation of T4 lysozyme hinge-bending motion by fluorescence correlation spectroscopy.

    Science.gov (United States)

    Yirdaw, Robel B; McHaourab, Hassane S

    2012-10-01

    Bacteriophage T4 Lysozyme (T4L) catalyzes the hydrolysis of the peptidoglycan layer of the bacterial cell wall late in the infection cycle. It has long been postulated that equilibrium dynamics enable substrate access to the active site located at the interface between the N- and C-terminal domains. Crystal structures of WT-T4L and point mutants captured a range of conformations that differ by the hinge-bending angle between the two domains. Evidence of equilibrium between open and closed conformations in solution was gleaned from distance measurements between the two domains but the nature of the equilibrium and the timescale of the underlying motion have not been investigated. Here, we used fluorescence fluctuation spectroscopy to directly detect T4L equilibrium conformational fluctuations in solution. For this purpose, Tetramethylrhodamine probes were introduced at pairs of cysteines in regions of the molecule that undergo relative displacement upon transition from open to closed conformations. Correlation analysis of Tetramethylrhodamine intensity fluctuations reveals hinge-bending motion that changes the relative distance and orientation of the N- and C-terminal domains with ≅ 15 μs relaxation time. That this motion involves interconversion between open and closed conformations was further confirmed by the dampening of its amplitude upon covalent substrate trapping. In contrast to the prevalent two-state model of T4L equilibrium, molecular brightness and number of particles obtained from cumulant analysis suggest that T4L populates multiple intermediate states, consistent with the wide range of hinge-bending angles trapped in the crystal structure of T4L mutants.

  6. 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

  7. Octamer formation in lysozyme solutions at the initial crystallization stage detected by small-angle neutron scattering.

    Science.gov (United States)

    Boikova, Anastasiia S; Dyakova, Yulia A; Ilina, Kseniia B; Konarev, Petr V; Kryukova, Alyona E; Kuklin, Alexandr I; Marchenkova, Margarita A; Nabatov, Boris V; Blagov, Alexandr E; Pisarevsky, Yurii V; Kovalchuk, Mikhail V

    2017-07-01

    Solutions of lysozyme in heavy water were studied by small-angle neutron scattering (SANS) at concentrations of 40, 20 and 10 mg ml(-1) with and without the addition of precipitant, and at temperatures of 10, 20 and 30°C. In addition to the expected protein monomers, dimeric and octameric species were identified in solutions at the maximum concentration and close to the optimal conditions for crystallization. An optimal temperature for octamer formation was identified and both deviation from this temperature and a reduction in protein concentration led to a significant decrease in the volume fractions of octamers detected. In the absence of precipitant, only monomers and a minor fraction of dimers are present in solution.

  8. Photoluminescence Mechanism of DNA-Templated Silver Nanoclusters: Coupling between Surface Plasmon and Emitter and Sensing of Lysozyme.

    Science.gov (United States)

    Liu, Xiaorong; Hu, Ruoxin; Gao, Zhidan; Shao, Na

    2015-06-02

    DNA-templated silver nanoclusters (DNA-AgNCs) have now been thrust into the limelight with their superior optical properties and potential biological applications. However, the origin of photoluminescence from DNA-AgNCs still remains unclear. In this work, DNA-AgNCs were synthesized and the photoluminescence properties as well as the biosensing applications of the designed DNA-AgNCs were investigated. The photoluminescence properties of the DNA-AgNCs were studied under three regions of excitation wavelength based on the UV-visible absorption spectra. It was deemed that the photoluminescence originated from coupling between the surface plasmon and the emitter in AgNCs when they were excited by visible light above 500 nm, and thus the emission wavelength varied with changing the excitation wavelength. The photoluminescence of the red-emitting-only AgNCs was the intrinsic fluorescence when excited from 200 to 400 nm, which was only related to the emitter; but for two components of blue- and red-emitting AgNCs, the emission wavelength varied with the excitation wavelength ranging from 300 to 360 nm, and the photoluminescence was a coupling between the surface plasmon and the emitter. The photoluminescence was only related to the surface plasmon when the AgNCs were excited from 400 to 500 nm. Four DNA probes were designed and each contained two parts: one part was the template used to synthesize AgNCs and it was same to all, and the other part was the lysozyme binding DNA (LBD) used to bind lysozyme and two kinds of LBD were studied. It was deemed that the difference in DNA bases, sequence, and secondary structure caused the synthesized DNA-AgNCs to be different in photoluminescence properties and sensing ability to lysozyme, and the sensing mechanism based on photoluminescence enhancement was also presented. This work explored the origin of photoluminescence and the sensing ability of DNA-AgNCs, and is hoped to make a better understanding of this kind of

  9. 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.

  10. Natural gas; Gas Natural

    Energy Technology Data Exchange (ETDEWEB)

    Lopes, Carlos A.; Moraes, Claudia C.D. [Eletricidade de Sao Paulo S.A. (ELETROPAULO), Sao Paulo, SP (Brazil); Fonseca, Carlos H.F. [Centrais Eletricas de Santa Catarina S.A., Florianopolis, SC (Brazil); Silva, Clecio Fabricio da; Alves, Ricardo P. [Companhia Paranaense de Energia (COPEL), Curitiba, PR (Brazil); Sposito, Edivaldo Soares; Hulle, Lutero [Espirito Santo Centrais Eletricas S.A. (ESCELSA), Vitoria, ES (Brazil); S. Martins, Icaro da [Centrais Eletricas do Norte do Brasil S.A. (ELETRONORTE), Belem, PA (Brazil); Vilhena, Joao Luiz S. de [Companhia Energetica de Minas Gerais (CEMIG), Belo Horizonte, MG (Brazil); Fagundes, Zaluar Aquino [Companhia Estadual de Energia Eletrica do Estado do Rio Grande do Sul, Porto Alegre, RS (Brazil)

    1996-12-31

    An increase in the consumption of natural gas in Brazil is an expected fact in what concerns energetic planning. This work presents the existing situation in what concerns natural gas utilization in the main world economies, as well as an analysis of the participation of this fuel among the energy final consumption per sources. The Brazilian consumption of natural gas is also analysed as well as the international agreement between Brazil and Bolivia for natural gas commercialization. Some legal, institutional and political aspects related to natural gas commercialization are also discussed. Finally, several benefits to be brought by the utilization of natural gas are presented 10 refs., 3 tabs.

  11. Insights into the structure-function relationships of pneumococcal cell wall lysozymes, LytC and Cpl-1.

    Science.gov (United States)

    Monterroso, Begoña; Sáiz, José Luis; García, Pedro; García, José Luis; Menéndez, Margarita

    2008-10-17

    The LytC lysozyme belongs to the autolytic system of Streptococcus pneumoniae and carries out a slow autolysis with optimum activity at 30 degrees C. Like all pneumococcal murein hydrolases, LytC is a modular enzyme. Its mature form comprises a catalytic module belonging to the GH25 family of glycosyl-hydrolases and a cell wall binding module (CBM), made of 11 sequence repeats, that is essential for activity and specifically targets choline residues present in pneumococcal lipoteichoic and teichoic acids. Here we show that the catalytic module is natively folded, and its thermal denaturation takes place at 45.4 degrees C. However, the CBM is intrinsically unstable, and the ultimate folding and stabilization of the active, monomeric form of LytC relies on choline binding. The complex formation proceeds in a rather slow way, and all sites (8.0 +/- 0.5 sites/monomer) behave as equivalent (Kd = 2.7 +/- 0.3 mm). The CBM stabilization is, nevertheless, marginal, and irreversible denaturation becomes measurable at 37 degrees C even at high choline concentration, compromising LytC activity. In contrast, the Cpl-1 lysozyme, a homologous endolysin encoded by pneumococcal Cp-1 bacteriophage, is natively folded in the absence of choline and has maximum activity at 37 degrees C. Choline binding is fast and promotes Cpl-1 dimerization. Coupling between choline binding and folding of the CBM of LytC indicates a high conformational plasticity that could correlate with the unusual alternation of short and long choline-binding repeats present in this enzyme. Moreover, it can contribute to regulate LytC activity by means of a tight, complementary binding to the pneumococcal envelope, a limited motility, and a moderate resistance to thermal denaturation that could also account for its activity versus temperature profile.

  12. Insights into the Structure-Function Relationships of Pneumococcal Cell Wall Lysozymes, LytC and Cpl-1*S⃞

    Science.gov (United States)

    Monterroso, Begoña; Sáiz, José Luis; García, Pedro; García, José Luis; Menéndez, Margarita

    2008-01-01

    The LytC lysozyme belongs to the autolytic system of Streptococcus pneumoniae and carries out a slow autolysis with optimum activity at 30 °C. Like all pneumococcal murein hydrolases, LytC is a modular enzyme. Its mature form comprises a catalytic module belonging to the GH25 family of glycosyl-hydrolases and a cell wall binding module (CBM), made of 11 sequence repeats, that is essential for activity and specifically targets choline residues present in pneumococcal lipoteichoic and teichoic acids. Here we show that the catalytic module is natively folded, and its thermal denaturation takes place at 45.4 °C. However, the CBM is intrinsically unstable, and the ultimate folding and stabilization of the active, monomeric form of LytC relies on choline binding. The complex formation proceeds in a rather slow way, and all sites (8.0 ± 0.5 sites/monomer) behave as equivalent (Kd = 2.7 ± 0.3 mm). The CBM stabilization is, nevertheless, marginal, and irreversible denaturation becomes measurable at 37 °C even at high choline concentration, compromising LytC activity. In contrast, the Cpl-1 lysozyme, a homologous endolysin encoded by pneumococcal Cp-1 bacteriophage, is natively folded in the absence of choline and has maximum activity at 37 °C. Choline binding is fast and promotes Cpl-1 dimerization. Coupling between choline binding and folding of the CBM of LytC indicates a high conformational plasticity that could correlate with the unusual alternation of short and long choline-binding repeats present in this enzyme. Moreover, it can contribute to regulate LytC activity by means of a tight, complementary binding to the pneumococcal envelope, a limited motility, and a moderate resistance to thermal denaturation that could also account for its activity versus temperature profile. PMID:18667432

  13. Analysis of technologies for natural gas transportation in Brazil: results comparison of the application of payback and NPV (Net Present Value) methods; Analise de tecnologias de transporte de gas natural no Brasil: comparacao dos resultados da aplicacao dos metodos 'payback' e VPL (Valor Presente Liquido)

    Energy Technology Data Exchange (ETDEWEB)

    Baioco, Juliana Souza; Santarem, Clarissa Andrade [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil). Dept. de Engenharia de Petroleo; Bone, Rosemarie Broeker; Ferreira Filho, Virgilio Jose Martins [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil). Dept. de Engenharia Industrial

    2008-07-01

    The increased demand for natural gas leads to global integration of markets, leading to decisions that cover the various technologies of transportation, noting the specific locations. The transport of natural gas considered more traditional (Liquefied Natural Gas and Pipeline) often unviable economically areas of operation due to cost. In this case, there are alternative technologies to reduce those costs. The article is to compare the technologies of transport, using the methodology of the Net Present Value (VPL) to identify one that has more positive VPL, which is the most profitable. Thus, in search of validate the results of SUBERO et al. (2004) for gas transport by Pipelines, Liquefied Natural Gas and Compressed Natural Gas. In addition, they are compared these results with the method of VPL and with the economic analysis presented in using the payback period of CHANG (2001) and SANTAREM et al. (2007). It was found that the results obtained in Brazil were identical to those obtained by CHANG (2001) and SUBERO et al. (2007), saving only some differences in magnitude due to the specific characteristics of the Brazilian economy. In other words, for the Brazilian case, the technology of Compressed Natural Gas (CNG) was the most economically viable with the method of VPL, followed by technology, Pipeline and Liquefied Natural Gas (LNG), regardless of the interest rates of 10% and 6.5% and periods of 20 and 30 years. The contribution of this work is to show that despite of the method, payback or VPL, the various alternatives for transporting natural gas to Brazil have the same ranking and economic viability. (author)

  14. "Journey to the Stars": Presenting What Stars Are to Global Planetarium Audiences by Blending Astrophysical Visualizations Into a Single Immersive Production at the American Museum of Natural History

    Science.gov (United States)

    Emmart, Carter; Mac Low, M.; Oppenheimer, B. R.; Kinzler, R.; Paglione, T. A. D.; Abbott, B. P.

    2010-01-01

    "Journey to the Stars" is the latest and fourth space show based on storytelling from data visualization at the Rose Center for Earth and Space at the American Museum of Natural History. This twenty five minute, full dome movie production presents to planetarium audiences what the stars are, where they come from, how they vary in type and over time, and why they are important to life of Earth. Over forty scientists from around the world contributed their research to what is visualized into roughly fifteen major scenes. How this production is directed into a consolidated immersive informal science experience with learning goals is an integrative process with many inputs and concerns for scientific accuracy. The goal is a seamless merger of visualizations at varying spatial and temporal scales with acuity toward depth perception, revealing unseen phenomena, and the layering of concepts together to build an understanding of stars; to blend our common experience of them in the sky with the uncommon meaning we have come to know through science. Scripted by Louise Gikow who has worked for Children's Television Workshop, narrated by Whoopie Goldberg, and musically scored by Robert Miller, this production strives to guide audiences through challenging scientific concepts by complimenting the natural beauty the subject matter presents with understandable prose and musical grandeur. "Journey to the Stars" was produced in cooperation with NASA's Science Mission Directorate, Heliophysics Division and is in release at major planetariums, worldwide.

  15. 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

  16. 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

  17. 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

  18. 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

  19. 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...

  20. 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

  1. 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

  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. 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. 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.

  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. 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,…

  10. 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

  11. 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

  12. 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

  13. 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

  14. 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

  15. 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.

  16. 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.

  17. 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

  18. 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.

  19. 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…

  20. 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

  1. 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

  2. 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.

  3. 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...

  4. 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.

  5. 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

  6. 中国自然保护区研究的现状与展望%Present conditions and prospects of the researches on nature reserves in China

    Institute of Scientific and Technical Information of China (English)

    郑朝贵; 朱诚

    2004-01-01

    The construction of nature reserves in China is reviewed in this paper,mainly including the number,type,administration and distribution of nature reserves,the progress in research on biodiversity,evaluation,management,sustainable development of nature reserves in China is summarized briefly,and some development tendencies of research on nature reserves are put forward.

  7. 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+.

  8. 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.

  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. Autoimmune Pancreatitis Presenting a Short Narrowing of Main Pancreatic Duct with Subsequent Progression to Diffuse Pancreatic Enlargement over 24 Months; Natural History of Autoimmune Pancreatitis

    Directory of Open Access Journals (Sweden)

    Shuichiro Umemura

    2014-05-01

    Full Text Available Context Initial pancreatogram and natural history of autoimmune pancreatitis (AIP have not been clarified, and there were few recent studies concerning the association between AIP and intraductal papillary mucinous neoplasm (IPMN. Case report We report an 81-yearold man with AIP associated with IPMN. Although the initial pancreatogram was normal, a short narrowing of the main pancreatic duct (MPD appeared during a follow-up for IPMN after 6 months, which was highly suggestive of pancreatic cancer. A narrowing of the MPD extended after 15 months, and this progressed to diffuse narrowing of the MPD with an elevation in the serum IgG4 levels after 24 months. Finally, the patient was diagnosed with diffuse-type AIP, according to the Japanese diagnostic criteria 2011 and the International Consensus Diagnostic Criteria. Considering the natural history of AIP, this marked change of the MPD is indicative of this condition. Conclusion Wereport a case of AIP presenting with a short narrowing of the MPD with subsequent progression to diffuse pancreatic enlargement during a follow-up for IPMN.

  12. A validated UHPLC-MS/MS method to quantify low levels of anabolic-androgenic steroids naturally present in urine of untreated horses.

    Science.gov (United States)

    Decloedt, Anneleen; Bailly-Chouriberry, Ludovic; Vanden Bussche, Julie; Garcia, Patrice; Popot, Marie-Agnes; Bonnaire, Yves; Vanhaecke, Lynn

    2015-06-01

    Doping control is a main priority for regulatory bodies of both the horse racing industry and the equestrian sports. Urine and blood samples are screened for the presence of hundreds of forbidden substances including anabolic-androgenic steroids (AASs). Based on the suspected endogenous origin of some AASs, with β-boldenone as the most illicit candidate, this study aimed to improve the knowledge of the naturally present AAS in horse urine. To this extent, a novel ultra high-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) method was developed and validated according to the Association of Official Racing Chemists (AORC) and European Commission (EC) guidelines, proving the power of this new method. Low limits of detection (0.2 ng/mL), good reproducibility (percentage of standard deviation (%RSD)  0.99 and lack-of-fit analysis) were obtained for all included AASs. With this method, urine samples of 105 guaranteed untreated horses (47 geldings, 53 mares, and 5 stallions serving as a control) were screened for β-boldenone and five related natural steroids: androstadienedione (ADD), androstenedione (AED), alpha-testosterone (αT), beta-testosterone (βT), and progesterone (P). Progesterone, β-testosterone, and α-testosterone were detected in more than half of the horses at low concentrations (horses (mares and geldings).

  13. Treatment effects of lysozyme-shelled microbubbles and ultrasound in inflammatory skin disease

    Science.gov (United States)

    Liao, Ai-Ho; Hung, Chi-Ray; Lin, Chieh-Fu; Lin, Yi-Chun; Chen, Hang-Kang

    2017-01-01

    Acne vulgaris is the most common skin disorder, and is caused by Propionibacterium acnes (P. acnes) and can induce inflammation. Antibiotic therapy often needs to be administered for long durations in acne therapy, which results in extensive antibiotic exposure. The present study investigated a new treatment model for evaluating the antibacterial effects of lysozyme (LY)-shelled microbubbles (MBs) and ultrasound (US)-mediated LY-shelled MBs cavitation against P. acnes both in vitro and in vivo, with the aims of reducing the dose and treatment duration and improving the prognosis of acne vulgaris. In terms of the in vitro treatment efficacy, the growth of P. acnes was inhibited by 86.08 ± 2.99% in the LY-shelled MBs group and by 57.74 ± 3.09% in the LY solution group. For US power densities of 1, 2, and 3 W/cm2 in the LY-shelled MBs group, the growth of P. acnes was inhibited by 95.79 ± 3.30%, 97.99 ± 1.16%, and 98.69 ± 1.13%, respectively. The in vivo results showed that the recovery rate on day 13 was higher in the US group with LY-shelled MBs (97.8 ± 19.8%) than in the LY-shelled MBs group (90.3 ± 23.3%). Our results show that combined treatments of US and LY-shelled MBs can significantly reduce the treatment duration and inhibit P.-acnes-induced inflammatory skin diseases. PMID:28117399

  14. Effect of convective disturbances induced by g-jitter on the periodic precipitation of lysozyme.

    Science.gov (United States)

    Lappa, M; Carotenuto, L

    2003-01-01

    Numerical simulations are carried out to investigate the crystallization process of a protein macromolecular substance under two different conditions: pure diffusive regime and microgravity conditions present on space laboratories. The configuration under investigation consists of a protein reactor and a salt chamber separated by an "interface". The interface is strictly related to the presence of agarose gel in one of the two chambers. Sedimentation and convection under normal gravity conditions are prevented by the use of gel in the protein chamber (pure diffusive regime). Under microgravity conditions periodic time-dependent accelerations (g-jitter) are taken into account. Novel mathematical models are introduced to simulate the complex phenomena related to protein nucleation and further precipitation (or resolution) according to the concentration distribution and in particular to simulate the motion of the crystals due to g-litter in the microgravity environment. The numerical results show that gellified lysozyme (crystals "locked"on the matrix of agarose gel) precipitates to produce "spaced deposits". The crystal formation results modulated in time and in space (Liesegang patterns), due to the non-linear interplay among transport, crystal nucleation and growth. The propagation of the nucleation front is characterized by a wave-like behavior. In microgravity conditions (without gel), g-jitter effects act modifying the phenomena with respect to the on ground gellified configuration. The role played by the direction of the applied sinusoidal acceleration with respect to the imposed concentration gradient (parallel or perpendicular) is investigated. It has a strong influence on the dynamic behaviour of the depletion zones and on the spatial distribution of the crystals. Accordingly the possibility to obtain better crystals for diffraction analyses is discussed.

  15. 2,4-D abatement from groundwater samples by photo-Fenton processes at circumneutral pH using naturally iron present. Effect of inorganic ions.

    Science.gov (United States)

    Gutiérrez-Zapata, Héctor M; Rojas, Karen L; Sanabria, Janeth; Rengifo-Herrera, Julián Andrés

    2017-03-01

    This study evaluated, at laboratory scale, if the using iron naturally present (0.3 mg L(-1)) and adding 10 mg L(-1) of hydrogen peroxide was effective to remove 24.3 mgL(-1) of 2,4-dichlorophenoxyacetic acid (2,4-D) from groundwater samples by simulated solar irradiation (global intensity = 300 W m(-2)). Under these conditions, the degradation of 2,4-D reached 75.2 % and the apparition of its main oxidation byproduct 2,4-dichlorophenol (DCP) was observed. On the other hand, pH exhibited an increasing from 7.0 to 8.3 during the experiment. Experiments using Milli-Q water at pH 7.0, iron, and H2O2 concentrations of 0.3 and 10 mg L(-1), respectively, were carried out in order to study the effect of ions such as carbonate species, phosphate, and fluoride in typical concentrations often found in groundwater. Ion concentrations were combined by using a factorial experimental design 2(3). Results showed that carbonates and fluoride did not produce a detrimental effect on the 2,4-D degradation, while phosphate inhibited the process. In this case, the pH increased also from 7.0 to 7.95 and 8.99. Effect of parameters such as pH, iron concentration, and hydrogen peroxide concentration on the 2,4-D degradation by the photo-Fenton process in groundwater was evaluated by using a factorial experimental design 2(3). Results showed that the pH was the main parameter affecting the process. This study shows for the first time that using the photo-Fenton process at circumneutral pH and iron naturally present seems to be a promising process to remove pesticides from groundwater.

  16. The natural history of West Nile virus infection presenting with West Nile virus meningoencephalitis in a man with a prolonged illness: a case report

    Directory of Open Access Journals (Sweden)

    Wood James B

    2011-05-01

    Full Text Available Abstract Introduction Estimates indicate that West Nile virus infects approximately one and a half million people in the United States of America. Up to 1% may develop West Nile virus neuroinvasive disease, in which infected patients develop any combination of meningitis, encephalitis, or acute paralysis. Case presentation A 56-year-old African-American man presented to our hospital with headache, restlessness, fever, myalgias, decreased appetite, and progressive confusion. A cerebrospinal fluid examination showed mild leukocytosis and an elevated protein level. Testing for routine infections was negative. Brain T2-weighted magnetic resonance imaging scans showed marked enlargement of caudate nuclei and increased intensity within the basal ganglia and thalami. A West Nile virus titer was positive, and serial brain magnetic resonance imaging scans showed resolving abnormalities that paralleled his neurological examination. Conclusion This report is unusual as it portrays the natural history and long-term consequences of West Nile virus meningoencephalitis diagnosed on the basis of serial brain images.

  17. 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

  18. 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.

  19. 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.

  20. 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.

  1. Saposins modulate human invariant Natural Killer T cells self-reactivity and facilitate lipid exchange with CD1d molecules during antigen presentation

    Science.gov (United States)

    Salio, Mariolina; Ghadbane, Hemza; Dushek, Omer; Shepherd, Dawn; Cypen, Jeremy; Gileadi, Uzi; Aichinger, Michael C.; Napolitani, Giorgio; Qi, Xiaoyang; van der Merwe, P. Anton; Wojno, Justyna; Veerapen, Natacha; Cox, Liam R.; Besra, Gurdyal S.; Yuan, Weiming; Cresswell, Peter; Cerundolo, Vincenzo

    2013-01-01

    Lipid transfer proteins, such as molecules of the saposin family, facilitate extraction of lipids from biological membranes for their loading onto CD1d molecules. Although it has been shown that prosaposin-deficient mice fail to positively select invariant natural killer T (iNKT) cells, it remains unclear whether saposins can facilitate loading of endogenous iNKT cell agonists in the periphery during inflammatory responses. In addition, it is unclear whether saposins, in addition to loading, also promote dissociation of lipids bound to CD1d molecules. To address these questions, we used a combination of cellular assays and demonstrated that saposins influence CD1d-restricted presentation to human iNKT cells not only of exogenous lipids but also of endogenous ligands, such as the self-glycosphingolipid β-glucopyranosylceramide, up-regulated by antigen-presenting cells following bacterial infection. Furthermore, we demonstrated that in human myeloid cells CD1d-loading of endogenous lipids after bacterial infection, but not at steady state, requires trafficking of CD1d molecules through an endo-lysosomal compartment. Finally, using BIAcore assays we demonstrated that lipid-loaded saposin B increases the off-rate of lipids bound to CD1d molecules, providing important insights into the mechanisms by which it acts as a “lipid editor,” capable of fine-tuning loading and unloading of CD1d molecules. These results have important implications in understanding how to optimize lipid-loading onto antigen-presenting cells, to better harness iNKT cells central role at the interface between innate and adaptive immunity. PMID:24248359

  2. 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.

  3. 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.

  4. 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...

  5. A Case Report of Primary Nasal Natural Killer (NK)/T-Cell Lymphoma in an African American Patient Presenting with Hemophagocytic Syndrome

    Science.gov (United States)

    Tan, Bowei; Abdelmalek, Cherif; O’Donnell, James E.; Toltaku, Thomas; Chaudhry, Rashid; Wang, Jen C.; Gotlieb, Vladimir

    2017-01-01

    Patient: Male, 55 Final Diagnosis: Primary NK-T cell lymphoma • nasal type Symptoms: Fever • nasal bleeding • nasal mass • weight loss Medication: — Clinical Procedure: Chemotherapy×2 cycles • radiation therap Specialty: Oncology Objective: Rare disease Background: Extranodal natural killer/T-cell lymphoma, nasal type (ENKTCL) is generally an aggressive and rare non-Hodgkin lymphoma. It is most common in East Asians, Native Americans, and South Americans, but is rarely reported in blacks. Case Report: A 55-year-old African American male born in Grenada presented with a left nostril mass with facial swelling and biopsy subsequently confirmed a diagnosis of extranodal NK/T-cell lymphoma, nasal type (ENKTCL). Immunochemistry was positive for CD2, cytoplasmic CD3, CD7, CD 43, CD 56, granzyme B, and TIA-1. In situ hybridization was positive for Epstein-Barr virus encoded ribonucleic acid (EBERs). Bone marrow aspiration did not show lymphoma involvement. The patient had progressive neutropenia upon presentation, with further investigations showing hepatomegaly, hyperferritinemia, and hemophagocytosis in the bone marrow. We reached a diagnosis of hemophagocytic syndrome. He was treated with a high-dose combination chemotherapy and radiation therapy; the neutropenia improved significantly with steroids as treatment for immune activation in the setting of hemophagocytic syndrome. Conclusions: To the best of our knowledge, this is the only second report of extranodal NK/T-cell lymphoma, nasal type in a black patient, and it raises the awareness of early recognition of rare manifestations of NK/T-cell lymphoma such as hemophagocytic syndrome. PMID:28193996

  6. 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...

  7. 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.

  8. 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....

  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. 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.

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. 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...

  9. 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.

  10. A rapid, quantitative liquid chromatography-mass spectrometry screening method for 71 active and 11 natural erectile dysfunction ingredients present in potentially adulterated or counterfeit products.

    Science.gov (United States)

    Lebel, Philippe; Gagnon, Jacques; Furtos, Alexandra; Waldron, Karen C

    2014-05-23

    A rapid LC-MS/MS method has been developed to simultaneously separate 71 erectile dysfunction (ED) drugs and 11 natural ingredients that are sometimes found alongside ED drugs, present in suspected adulterated or counterfeit samples. The separation was achieved in 10min using 2.6μm fused-core C18 particles in a 100×2.1mm column coupled to an LTQ Orbitrap XL mass spectrometer operated in positive electrospray mode. Using a straightforward methanolic extraction procedure, recovery from real samples (tablets, capsules, oral liquids and herbal products) was 92-111% and the lower and upper limits of detection and quantification were in the sub ng/mL and the sub μg/mL ranges, respectively. The intra- and inter-assay precision were ≤3.2% and 10.4% respectively across three concentrations of standards (50, 250 and 1000ng/mL) measured for 4 representative drugs spiked into a tablet-based matrix. This behavior was consistently observed for all the other compounds. The mass accuracy was less than 3ppm. Moreover, an advantage of this method is that the full scan event in the acquisition method associated with the high resolution of the Orbitrap XL allows post-analysis identification, in an untargeted approach, of additional species in the complex matrices. Our LC-MS/MS method for ED drugs was successfully applied to 32 samples and the drug identifications were in 100% agreement with those obtained by the conventional methods HPLC-UV and GC-MS. Following the complete validation of the ED method, it has been introduced in the current counterfeit identification procedures at Health Canada. Copyright © 2014 Elsevier B.V. All rights reserved.

  11. Diversity of natural self-derived ligands presented by different HLA class I molecules in transporter antigen processing-deficient cells.

    Directory of Open Access Journals (Sweden)

    Elena Lorente

    Full Text Available The transporter associated with antigen processing (TAP translocates the cytosol-derived proteolytic peptides to the endoplasmic reticulum lumen where they complex with nascent human leukocyte antigen (HLA class I molecules. Non-functional TAP complexes and viral or tumoral blocking of these transporters leads to reduced HLA class I surface expression and a drastic change in the available peptide repertoire. Using mass spectrometry to analyze complex human leukocyte antigen HLA-bound peptide pools isolated from large numbers of TAP-deficient cells, we identified 334 TAP-independent ligands naturally presented by four different HLA-A, -B, and -C class I molecules with very different TAP dependency from the same cell line. The repertoire of TAP-independent peptides examined favored increased peptide lengths and a lack of strict binding motifs for all four HLA class I molecules studied. The TAP-independent peptidome arose from 182 parental proteins, the majority of which yielded one HLA ligand. In contrast, TAP-independent antigen processing of very few cellular proteins generated multiple HLA ligands. Comparison between TAP-independent peptidome and proteome of several subcellular locations suggests that the secretory vesicle-like organelles could be a relevant source of parental proteins for TAP-independent HLA ligands. Finally, a predominant endoproteolytic peptidase specificity for Arg/Lys or Leu/Phe residues in the P(1 position of the scissile bond was found for the TAP-independent ligands. These data draw a new and intricate picture of TAP-independent pathways.

  12. 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...

  13. 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.

  14. Cavity as a source of conformational fluctuation and high-energy state: High-pressure NMR study of a cavity-enlarged mutant of T4 lysozyme

    CERN Document Server

    Maeno, Akihiro; Hirata, Fumio; Otten, Renee; Dahlquist, Frederick W; Yokoyama, Shigeyuki; Akasaka, Kazuyuki; Mulder, Frans A A; Kitahara, Ryo

    2014-01-01

    Although the structure, function, conformational dynamics, and controlled thermodynamics of proteins are manifested by their corresponding amino acid sequences, the natural rules for molecular design and their corresponding interplay remain obscure. In this study, we focused on the role of internal cavities of proteins in conformational dynamics. We investigated the pressure-induced responses from the cavity-enlarged L99A mutant of T4 lysozyme, using high-pressure NMR spectroscopy. The signal intensities of the methyl groups in the 1H/13C HSQC spectra, particularly those around the enlarged cavity, decreased with the increasing pressure, and disappeared at 200 MPa, without the appearance of new resonances, thus indicating the presence of heterogeneous conformations around the cavity within the ground state ensemble. Above 200 MPa, the signal intensities of more than 20 methyl groups gradually decreased with the increasing pressure, without the appearance of new resonances. Interestingly, these residues closel...

  15. 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.

  16. 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.

  17. 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

  18. Mechanisms of systemic vasodilation by lysozyme-c in septic shock.

    Science.gov (United States)

    Gotes, Jose; Kasian, Krika; Jacobs, Hans; Cheng, Zhao-Qin; Mink, Steven N

    2012-02-01

    In septic shock (SS), cardiovascular collapse is caused by the release of inflammatory mediators. We previously found that lysozyme-c (Lzm-S), released from leukocytes, contributed to systemic vasodilation in a canine model of SS. We then delineated the pathway by which this occurs in a canine carotid artery organ bath preparation (CAP). We showed that Lzm-S could intrinsically generate hydrogen peroxide (H(2)O(2)) and that H(2)O(2) subsequently reacted with endogenous catalase to form compound I, an oxidized form of catalase. In turn, compound I led to an increase in cyclic guanosine 3',5'-monophosphate to produce vasodilation. However, it was not clear from previous studies whether it is necessary for Lzm-S to bind to the vasculature to cause vasodilation or, alternatively, whether the generation of H(2)O(2) by Lzm-S in the surrounding medium is all that is required. We examined this question in the present study in which we used multiple preparations. In a partitioned CAP, we found that when we added Lzm-S to a partitioned space in which a semipermeable membrane prevented diffusion of Lzm-S to the carotid artery tissue, vasodilation still occurred because of diffusion of H(2)O(2). On the other hand, we found that Lzm-S could accumulate within the vascular smooth muscle layer (VSML) after 7 h of SS in a canine model. We also determined that when Lzm-S was located in close proximity to vascular smooth muscle cells, it could generate H(2)O(2) to produce lengthening in a human cell culture preparation. We conclude that there are two mechanisms by which Lzm-S can cause vasodilation in SS. In one instance, H(2)O(2) generated by Lzm-S in plasma diffuses to the VSML to cause vasodilation. In a second mechanism, Lzm-S directly binds to the VSML, where it generates H(2)O(2) to produce vasodilation.

  19. Template Directed Synthesis and Characterization of Organic Mesoporous Polymers and their Adsorption Performance for Lysozyme

    Science.gov (United States)

    Sridhar, Manasa

    Three homologous series of MCFs with diverse pore topologies have been synthesized by symbiotic interplay of TMB/P123 (R1) and TEOS/P123 (R2) weight ratios in the initial microemulsion. It was found that the MCFs synthesized at R2 greater than the conventional value suffered significant lag in the mesopore volumes and areas at low concentrations of TMB. However, when R1 is increased beyond 1.0, the difference in the pore volumes and areas became negligible. Many key findings were reported through this study. TEM images revealed that the MCFs synthesized at higher values of R2 prematurely attained larger average pore sizes accompanied with portions displaying constricted worm-like mesostructures. Such bimodal mesophases are accounted by the swelling action of excess amounts of ethanol discharged due to the hydrolysis of increased amounts of TEOS present in the microemulsion along with partial TEOS dissolution in the hydrophobic PPO cores of the TMB/P123 micelles. MCFs synthesized at highest R2 value of 4.4 exhibits unique interconnected rod-like morphologies which are usually not observed for conventional MCFs. MCF produced using R1 = 2.5 and R2 = 3.0 exhibit bimodal mesophases consisting of polyhedral nanofoam-like textures along with regular spherical pores. USAXS results indicate wall thickness as large as 11 nm for MCFs produced at R2 =4.4. These MCFs of interesting mesostructures were employed as nanoscopic templates to produce Mesocellular Phenol Formaldehyde Foams (MPFFs) using vacuum-assisted incipient wetness impregnation technique. The nanocasted MPFFs show large pore volumes up to 1.4 cm3/g, BET surface areas more than 900 m2/g and large pore diameters in the range 27--99 nm depending on the MCF scaffold used. All the MPFFs showed faithful replication of the cavity sizes of their corresponding MCF parent templates. Stunningly, trimodal MPFFs resulted from the nanocasting of MCFs with R1 > 2.2. The resulting pore sizes were attributed to the original

  20. Effect of electrical field strength applied by PEF processing and storage temperature on the outgrowth of yeasts and moulds naturally present in a fresh fruit smoothie.

    Science.gov (United States)

    Timmermans, R A H; Nederhoff, A L; Nierop Groot, M N; van Boekel, M A J S; Mastwijk, H C

    2016-08-02

    Pulsed electrical field (PEF) technology offers an alternative to thermal pasteurisation of high-acid fruit juices, by extending the shelf life of food products, while retaining its fresh taste and nutritional value. Substantial research has been performed on the effect of electrical field strength on the inactivation kinetics of spoilage and pathogenic micro-organisms and on the outgrowth of spoilage micro-organisms during shelf life. However, studies on the effect of electrical field strength on the inactivation and outgrowth of surviving populations during shelf life are missing. In this study, we assessed the influence of electrical field strength applied by PEF processing and storage temperature on the outgrowth of surviving yeast and mould populations naturally present in fresh fruit smoothie in time. Therefore, an apple-strawberry-banana smoothie was treated in a continuous-flow PEF system (130L/h), using similar inlet and outlet conditions (preheating temperature 41°C, maximum temperature 58°C) to assure that the amount of energy across the different conditions was kept constant. Smoothies treated with variable electrical field strengths (13.5, 17.0, 20.0 and 24.0kV/cm) were compared to smoothies without treatment for outgrowth of yeasts and moulds. Outgrowth of yeasts and moulds stored at 4°C and 7°C was analysed by plating and visual observation and yeast growth was modelled using the modified logistic growth model (Zwietering model). Results showed that the intensity of the electrical field strength had an influence on the degree of inactivation of yeast cells, resulting in a faster outgrowth over time at lower electrical field strength. Outgrowth of moulds over time was not affected by the intensity of the electrical field strength used. Application of PEF introduces a trade-off between type of spoilage: in untreated smoothie yeasts lead to spoilage after 8days when stored at 4 or 7°C, whereas in PEF treated smoothie yeasts were (partly

  1. Parthenogenetic embryo-like structures in the human ovarian surface epithelium cell culture in postmenopausal women with no naturally present follicles and oocytes.

    Science.gov (United States)

    Virant-Klun, Irma; Rozman, Primoz; Cvjeticanin, Branko; Vrtacnik-Bokal, Eda; Novakovic, Srdjan; Rülicke, Thomas; Dovc, Peter; Meden-Vrtovec, Helena

    2009-01-01

    Little is known about parthenogenesis in the human ovary. What is known is related to patients with teratoma in their medical history. Ovarian surface epithelium (OSE) was often proposed as a source of ovarian stem cells with an embryonic character in the past, and was also termed "germinal epithelium." The aim of this study was to isolate putative stem cells from OSE scrapings, to set up an OSE cell culture, to follow the in vitro oogenesis and possible formation of parthenogenetic embryos in 21 postmenopausal women with no naturally present follicles and oocytes. Small round cells with a bubble-like structure and with a diameter from 2 to 4 microm were isolated from the material obtained by OSE scrapings in all women. They expressed early embryonic developmental markers such as stage-specific embryonic antigen-4 (SSEA-4) surface antigen and Oct-4, Nanog, Sox-2, and c-kit transcription factors. These cells were separated by density gradient centrifugation and grown in vitro, where they proliferated and formed embryoid body-like structures. Their markers of pluripotency such as telomerase activity were decreased during in vitro culture and they did not form teratoma after the injection into SCID mice. Some of them grew intensively and reached a diameter of approximately 20 microm after 5-7 days of culture. In the OSE cell culture, oocyte-like cells developed among them, which reached a diameter up to 95 mum, and expressed Oct-4, c-kit, VASA, and ZP2 transcription markers after 20 days of culture. Some of them expressed a zona pellucida-like structure and rarely germinal vesicle- and polar body-like structures. At the same time, parthenogenetic blastocyst-like structures developed, which expressed transcription markers Oct-4, Sox-2, and Nanog and were normal for chromosomes X, Y, 13, 16, 18, 21, and 22. In conclusion, the discovered cells expressed embryonic stem cell markers, gave rise to embryoid body-, oocyte-, and blastocyst-like structures, and might be

  2. Developing a Natural Gas-Powered Bus Rapid Transit Service: A Case Study on Leadership: Roaring Fork Transportation Authority (Presentation); NREL (National Renewable Energy Laboratory)

    Energy Technology Data Exchange (ETDEWEB)

    Schroeder, A.

    2015-03-01

    The Roaring Fork Transportation Authority (RFTA) represents a series of unique successes in alternative fuel deployment by pushing the envelope with innovative solutions. In the last year, RFTA demonstrated the ability to utilize compressed natural gas buses at a range of altitudes, across long distances, in extreme weather conditions and in a modern indoor fueling and maintenance facility - allwhile saving money and providing high-quality customer service. This case study will highlight how the leadership of organizations and communities that are implementing advances in natural gas vehicle technology is paving the way for broader participation.

  3. 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].

  4. 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.

  5. Establishing Antibacterial Multilayer Films on the Surface of Direct Metal Laser Sintered Titanium Primed with Phase-Transited Lysozyme

    Science.gov (United States)

    Guan, Binbin; Wang, Haorong; Xu, Ruiqing; Zheng, Guoying; Yang, Jie; Liu, Zihao; Cao, Man; Wu, Mingyao; Song, Jinhua; Li, Neng; Li, Ting; Cai, Qing; Yang, Xiaoping; Li, Yanqiu; Zhang, Xu

    2016-11-01

    Direct metal laser sintering is a technology that allows the fabrication of titanium (Ti) implants with a functional gradation of porosity and surface roughness according to three-dimensional (3D) computer data. The surface roughness of direct metal laser sintered titanium (DMLS-Ti) implants may provide abundant binding sites for bacteria. Bacterial colonization and subsequent biofilm formation can cause unsatisfactory cell adhesion and implant-related infections. To prevent such infections, a novel phase-transited lysozyme (PTL) was utilized as an initial functional layer to simply and effectively prime DMLS-Ti surfaces for subsequent coating with antibacterial multilayers. The purpose of the present study was to establish a surface with dual biological functionality. The minocycline-loaded polyelectrolyte multilayers of hyaluronic acid (HA) and chitosan (CS) formed via a layer-by-layer (LbL) self-assembly technique on PTL-functionalized DMLS-Ti were designed to inhibit pathogenic microbial infections while allowing the DMLS-Ti itself and the modified coatings to retain acceptable biocompatibility. The experimental results indicate that the DMLS-Ti and the hydrogel treated surfaces can inhibit early bacterial adhesion while completely preserving osteoblast functions. This design is expected to gain considerable interest in the medical field and to have good potential for applications in multifunctional DMLS-Ti implants.

  6. Fire history of dark needle coniferous forests in Pechora-Ilych nature reserve since second half of XIX century to present time

    Directory of Open Access Journals (Sweden)

    A. A. Aleynikov

    2015-12-01

    Full Text Available A study of the vegetation cover current state in any area should start from detailed investigation of its land-use history. Historic factors are of particular importance for forest ecosystems of protected nature areas as usually they are regarded as models and their history is neglected. The article describes fire history of the piedmont area of Pechora-Ilych biosphere nature reserve based on high resolution remote sensing data analysis and historical records. Such method allows reconstruction of forest fires back to 150 years ago. Field research of the tree stands age structure is needed to reveal older fires. 89 burns of 78 893 ha total area were detected, which is 11 % of the piedmont area of the reserve. The burns are distributed unevenly across the area: 76 % are in the Ilych river basin and the rest are in the Pechora river basin. All burns are classified into 4 types according to the periods during which they happened. Burned areas in both river basins changed during these periods: major part of the forest cover in the Ilych basin was damaged before the reserve was established, in the Pechora river basin -in the first decade after its foundation. Only 20 burns are precisely dated out of 73 burns happened in the XX century. Causes are also not determined for all fires. Probably both natural (lightning and anthropogenic factors caused fires. Known anthropogenic fires are allocated to settlements and floating rivers and cover huge areas (thousands and tens of thousands hectares. Natural fires are at distant watershed areas and are significantly smaller (tens and hundreds hectares.

  7. Blue natural organic dyestuffs--from textile dyeing to mural painting. Separation and characterization of coloring matters present in elderberry, logwood and indigo.

    Science.gov (United States)

    Pawlak, Katarzyna; Puchalska, Maria; Miszczak, Agata; Rosłoniec, Elzbieta; Jarosz, Maciej

    2006-05-01

    Natural dyestuffs used for painting or dyeing of textiles are complex mixtures of compounds of various chemical properties. Proper identification of the dye used by a painter and, even better, its origin is possible only when its compositional 'fingerprint' can be evaluated. For this reason gradient program for liquid chromatographic separation of 16 color compounds--components of natural blue dyes: elderberry, logwood and indigo--has been developed. Two detector systems were used simultaneously: UV-Vis spectrophotometry (at 280, 445, 520 and 600 nm) and ESI mass spectrometry (positive and negative SIM mode). It was found that fragmentation observed in ESI-MS is affected not only by ion source parameters, but also by chromatographic conditions, especially in case of the less stable substances: cyanidin glucosides, tannic acid, rutin and hematoxylin. Examination of characteristic dissociation pathways of the compounds under investigation after direct admission into ion source or after chromatographic separation allowed to select proper ions for SIM detection and to develop novel and efficient reversed phase high performance liquid chromatographic (RP-HPLC)-UV-Vis/ESI-MS method for the analysis of natural blue dyes. The procedure was successfully applied for identification of indigotin and carminic acid-main colorants extracted from a fiber taken from the blue-red 'Italian' tapestry (the collection of the National Museum in Warsaw, Poland).

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. Self-assembly of lysozyme on the surfaces of gold nanoparticles

    Institute of Scientific and Technical Information of China (English)

    Ming Hui Xiang; Xiao Xu; Na Li; Ke An Li

    2011-01-01

    The interaction of lysozyme (Lys) and gold nanoparticles was investigated via UV-vis absorption and resonance light-scattering method. There are some changes of the plasmon absorption and resonance light-scattering of gold nanoparticles that were observed via the addition of Lys. The normalized plasmon absorption and resonance light-scattering intensity with gold nanoparticles were both linear with 1-20 nmol/L Lys. A simple model about the component of the gold nanoparticles and Lys complex was established and the calculated result was fitted well in their concentration ratio. Furthermore, the activity analysis of Lys showed that the interaction was weak and nondestructive.

  13. N-terminal T4 lysozyme fusion facilitates crystallization of a G protein coupled receptor.

    Directory of Open Access Journals (Sweden)

    Yaozhong Zou

    Full Text Available A highly crystallizable T4 lysozyme (T4L was fused to the N-terminus of the β(2 adrenergic receptor (β(2AR, a G-protein coupled receptor (GPCR for catecholamines. We demonstrate that the N-terminal fused T4L is sufficiently rigid relative to the receptor to facilitate crystallogenesis without thermostabilizing mutations or the use of a stabilizing antibody, G protein, or protein fused to the 3rd intracellular loop. This approach adds to the protein engineering strategies that enable crystallographic studies of GPCRs alone or in complex with a signaling partner.

  14. Amylase: creatinine clearance ratio and urinary excretion of lysozyme in acute pancreatitis and acute duodenal perforation.

    Science.gov (United States)

    Berger, G M; Cowlin, J; Turner, T J

    1976-09-18

    The amylase:creatinine clearance ratio in patients suffering from acute pancreatitis or acute duodenal perforation was higher than normal in both groups of patients. These findings cast doubt on the value of this parameter as a specific index of acute pancreatitis. The mechanism or mechanisms underlying the increased amylase excretion have not been determined. However, the markedly elevated urinary excretion of lysozyme observed in some patients suggests, by analogy, that diminished tubular reabsorption of amylase may contribute towards the elevated amylase:creatinine ratio.

  15. Raman mapping of mannitol/lysozyme particles produced via spray drying and single droplet drying

    DEFF Research Database (Denmark)

    Pekka Pajander, Jari; Matero, Sanni Elina; Sloth, Jakob

    2015-01-01

    PURPOSE: This study aimed to investigate the effect of a model protein on the solid state of a commonly used bulk agent in spray-dried formulations. METHODS: A series of lysozyme/mannitol formulations were spray-dried using a lab-scale spray dryer. Further, the surface temperature of drying droplet......-ray powder diffractometry (XRPD) and Raman microscopy. Partial Least Squares Discriminant Analysis was used for analyzing the Raman microscopy data. RESULTS: XRPD results indicated that a mixture of β-mannitol and α-mannitol was produced in the spray-drying process which was supported by the Raman analysis...

  16. Correlation between calculated molecular descriptors of excipient amino acids and experimentally observed thermal stability of lysozyme

    DEFF Research Database (Denmark)

    Meng-Lund, Helena; Friis, Natascha; van de Weert, Marco

    2017-01-01

    A quantitative structure-property relationship (QSPR) between protein stability and the physicochemical properties of excipients was investigated to enable a more rational choice of stabilizing excipients than prior knowledge. The thermal transition temperature and aggregation time were determined...... analysis was applied to correlate the descriptors with the experimental results. It was possible to identify descriptors, i.e. amino acids properties, with a positive influence on either transition temperature or aggregation onset time, or both. A high number of hydrogen bond acceptor moieties was the most....... The QSPR shows good correlation between calculated molecular descriptors and the measured stabilizing effect of amino acids on lysozyme....

  17. Direct biomolecule binding on nonfouling surfaces via newly discovered supramolecular self-assembly of lysozyme under physiological conditions.

    Science.gov (United States)

    Yang, Peng

    2012-08-01

    When lysozyme is dissolved in a neutral HEPES buffer solution (pH = 7.4) with 0.001-0.050 M TCEP added, a fast phase transition process occurs and the resulting novel fiber-like hierarchical supramolecular assemblies made by primary spherical-particle aggregation can function as a "superglue" that binds strongly and quickly onto non-fouling coatings. This binding is highly selective towards lysozyme, and excludes synthetic, chemical/physical activation/deactivation (blocking) steps. By using biotinylated lysozyme, such a phase transition quickly creates a perfect biotinylated surface on non-fouling surfaces for avidin binding, showing great potential for the development of low-cost and practical biochips.

  18. Dimer formation in radiation-irradiated aqueous solution of lysozyme studied by light-scattering-intensity measurement

    Energy Technology Data Exchange (ETDEWEB)

    Hashimoto, S.; Masuda, T.; Kondo, M. (Institute of Physical and Chemical Research, Wako, Saitama (Japan); Tokyo Metropolitan Univ. (Japan). Faculty of Science); Seki, H.; Imamura, M. (Institute of Physical and Chemical Research, Wako, Saitama (Japan))

    1981-07-01

    The reaction of lysozyme with OH radical, Br/sub 2/ anion radical, and e/sup -/sub(aq), produced in an aqueous solution by pulsed electrons and ..gamma..-rays, were investigated. Irradiated enzymes showed an increase in the light scattering intensity (LSI) which is proportional to the absorbed dose. Results obtained from SDS gel electrophoresis confirm dimerization of lysozyme, which is considered to be responsible for the increase in LSI. It was found that the rate constant of the dimerization of protein radicals produced in the reaction with OH radical is 2k = (1.0+-0.3) x 10/sup 6/M/sup -1/s/sup -1/ and the yield of the dimerization is 0.6 in G. The enzymatic activity of the dimer is shown to be reduced to about 30 per cent of that of the intact enzyme. It is concluded that the radiation-induced inactivation of lysozyme is largely due to dimerization.

  19. Dimer formation in radiation-irradiated aqueous solution of lysozyme studied by light-scattering-intensity measurement.

    Science.gov (United States)

    Hashimoto, S; Seki, H; Masuda, T; Imamura, M; Kondo, M

    1981-07-01

    The reaction of lysozyme with OH., Br.-2 and e-aq, produced in an aqueous solution by pulsed electrons and gamma-rays, were investigated. Irradiated enzymes showed an increase in the light scattering intensity (LSI) which is proportional to the absorbed dose. Results obtained from SDS gel electrophoresis confirm dimerization of lysozyme, which is considered to be responsible for the increase in LSI. It was found that the rate constant of the dimerization of protein radicals produced in the reaction with OH. is 2K=(1.0 +/- 0.3) X 10(6)M-1 s-1 and the yield of the dimerization is 0.6 in G. The enzymatic activity of the dimer is shown to be reduced to about 30 per cent of that of the intact enzyme. It is concluded that the radiation-induced inactivation of lysozyme is largely due to dimerization.

  20. Present Situation of Natural Resources of Andrias davidianus and Protection Countermeasures%中国大鲵自然资源现状及管理对策

    Institute of Scientific and Technical Information of China (English)

    文立华

    2013-01-01

    首先对我国大鲵自然资源的现状进行分析,然后探讨大鲵资源衰退的根本原因,并提出保护大鲵自然资源的对策.结果表明,酷渔滥捕、栖息地被破坏和水质污染是造成资源衰退的主要原因;保护生态环境、开展增殖放流等措施对大鲵自然资源的保护具有十分重要的意义.%The status of natural resources of Andrias davidianus was analyzed, the root causes for decreases were discussed, and the counter-measures for protection were put forward. The results showed that overfishing, damaged habitats and polluted water quality are the main causes ; protecting eco-environment, breeding and releasing are significant measures for protection of natural resources of A. davidianus.

  1. Synthesis of Novel Phosphorylated Daidzein Derivatives and ESI Investigation on Their Non-Covalent Complexes with Lysozyme

    Institute of Scientific and Technical Information of China (English)

    CHEN, Xiao-Lan; SHI, Xiao-Na; QU, Ling-Bo; YUAN, Jin-Wei; LU, Jian-Sha; ZHAO, Yu-Fen

    2007-01-01

    Daidzein (7,4'-dihydroxyisoflavone) was phosphorylated by a modified Atherton-Todd reaction. The structures of the five target product, were determined by X-ray, IR, NMR and ESI-MS. Electrospray ionization results show that in the gas phase all the phosphorylated daidzein derivatives could form non-covalent complexes with the protein lysozyme, while non-covalent complexes were not detected in the mixed solution of daidzein with lysozyme.Relative affinity of every non-covalent complex was obtained according to its different decomposition orifice voltage.

  2. Characterization of the Bacterial Community Naturally Present on Commercially Grown Basil Leaves: Evaluation of Sample Preparation Prior to Culture-Independent Techniques

    Directory of Open Access Journals (Sweden)

    Siele Ceuppens

    2015-08-01

    Full Text Available Fresh herbs such as basil constitute an important food commodity worldwide. Basil provides considerable culinary and health benefits, but has also been implicated in foodborne illnesses. The naturally occurring bacterial community on basil leaves is currently unknown, so the epiphytic bacterial community was investigated using the culture-independent techniques denaturing gradient gel electrophoresis (DGGE and next-generation sequencing (NGS. Sample preparation had a major influence on the results from DGGE and NGS: Novosphingobium was the dominant genus for three different basil batches obtained by maceration of basil leaves, while washing of the leaves yielded lower numbers but more variable dominant bacterial genera including Klebsiella, Pantoea, Flavobacterium, Sphingobacterium and Pseudomonas. During storage of basil, bacterial growth and shifts in the bacterial community were observed with DGGE and NGS. Spoilage was not associated with specific bacterial groups and presumably caused by physiological tissue deterioration and visual defects, rather than by bacterial growth.

  3. Productivity and phenological responses of natural vegetation to present and future inter-annual climate variability across semi-arid river basins in Chile.

    Science.gov (United States)

    Glade, Francisco E; Miranda, Marcelo D; Meza, Francisco J; van Leeuwen, Willem J D

    2016-12-01

    Time series of vegetation indices and remotely sensed phenological data offer insights about the patterns in vegetation dynamics. Both are useful sources of information for analyzing and monitoring ecosystem responses to environmental variations caused by natural and anthropogenic drivers. In the semi-arid region of Chile, climate variability and recent severe droughts in addition to land-use changes pose threats to the stability of local ecosystems. Normalized difference vegetation index time series (2000-2013) data from the moderate resolution imaging spectroradiometer (MODIS) was processed to monitor the trends and patterns of vegetation productivity and phenology observed over the last decade. An analysis of the relationship between (i) vegetation productivity and (ii) precipitation and temperature data for representative natural land-use cover classes was made. Using these data and ground measurements, productivity estimates were projected for two climate change scenarios (RCP2.6 and RCP8.5) at two altitudinal levels. Results showed negative trends of vegetation productivity below 2000 m a.s.l. and positive trends for higher elevations. Phenology analysis suggested that mountainous ecosystems were starting their growing period earlier in the season, coinciding with a decreased productivity peak during the growing season. The coastal shrubland/grassland land cover class had a significant positive relation with rainfall and a significant negative relation with temperature, suggesting that these ecosystems are vulnerable to climate change. Future productivity projections indicate that under an RCP8.5 climate change scenario, productivity could decline by 12% in the period of 2060-2100, leading to a severe vegetation degradation at lower altitudes and in drier areas.

  4. The influence of a homologous protein impurity on lysozyme crystal growth

    Science.gov (United States)

    Bhamidi, V.; Hanson, B. L.; Edmundson, A.; Skrzypczak-Jankun, E.; Schall, C.

    1999-08-01

    The effect of a structurally similar protein impurity, turkey ( Meleagris gallopavo) egg-white lysozyme (TEWL) on crystallization of the host protein, hen-egg-white lysozyme (HEWL) from chicken ( Gallus gallus) was studied under varying impurity and host solution concentrations. A change in morphology is observed when crystals of HEWL are grown in the presence of TEWL. As the relative amount of TEWL increases, HEWL crystals become more elongated in the [0 0 1] direction. Elongation is more pronounced in samples with lower initial concentrations of HEWL than in samples with higher initial concentrations. This behavior is consistent with that of impurities in small molecule crystal growth and with predictions based on the Kubota-Mullin model. The observed effect on the growth process can be attributed to the apparent inhibition in the [1 1 0] crystal growth direction of HEWL by TEWL since slowly growing faces become dominant faces in crystal growth. Incorporation of TEWL into HEWL crystals grown in a sitting drop batch method was measured using cation exchange chromatography. The results indicate that impurity incorporation is associated with increasing supersaturation. This conclusion is consistent with a kinetically controlled process of impurity incorporation. The observed impurity effects are most probably associated with the interchange of glutamine in position 41 of HEWL by histidine in TEWL.

  5. Protein adsorption on a hydrophobic surface: a molecular dynamics study of lysozyme on graphite.

    Science.gov (United States)

    Raffaini, Giuseppina; Ganazzoli, Fabio

    2010-04-20

    Adsorption of human lysozyme on hydrophobic graphite is investigated through atomistic computer simulations with molecular mechanics (MM) and molecular dynamics (MD) techniques. The chosen strategy follows a simulation protocol proposed by the authors to model the initial and the final adsorption stage on a bare surface. Adopting an implicit solvent and considering 10 starting molecular orientations so that all the main sides of the protein can face the surface, we first carry out an energy minimization to investigate the initial adsorption stage, and then long MD runs of selected arrangements to follow the surface spreading of the protein maximizing its adsorption strength. The results are discussed in terms of the kinetics of surface spreading, the interaction energy, and the molecular size, considering both the footprint and the final thickness of the adsorbed protein. The structural implications of the final adsorption geometry for surface aggregation and nanoscale structural organization are also pointed out. Further MD runs are carried out in explicit water for the native structure and the most stable adsorption state to assess the local stability of the geometry obtained in implicit solvent, and to calculate the statistical distribution of the water molecules around the whole lysozyme and its backbone.

  6. Lysozyme refolding at high concentration by dilution and size—exclusion chromatography

    Institute of Scientific and Technical Information of China (English)

    高永贵; 关怡新; 姚善泾; CHOMan-gi

    2003-01-01

    This study of renaturation by dilution and size exclusion chromstography(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 tp 40 mg/mL by dilu-tion and 100 mg/mL by SEC,with the yield of the former being more than 40% and that of the latter being 34.8%.Especislly,under the condition of 30 min iterval 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.

  7. Transfer of Lysozyme Gene into indica Parents of Hybrid Rice by Backcrossing

    Institute of Scientific and Technical Information of China (English)

    YI Zi-li; WANG Zi-xuan; QIN Jing-ping; JIANG Jian-xiong; TAN Yan-ning; ZHOU Qing-ming

    2006-01-01

    Alysozyme gene resistant to rice blast was transferred from the donor transgenic japonica rice Zhonghua 9 (D2-1-2) into a sterile line Pei'ai 64S(PA 64S) and restorer line 9311 of the two-line hybrid rice Liangyoupeijiu, and the restorer line Minghui 63 (MH63) of three-line hybrid rice Shanyou 63 by successive backcrossing. The PCR analysis confirmed that foreign lysozyme gene was B2F2 9311, B2F2 MH63 and B1F2 PA64S, indicating that the foreign gene was stably inherited over successive generations as a dominant single copy gene. The resistance against rice blast in backcross or selfed generations and corresponding testcross combinations were investigated in 2003 and 2004. The results showed that the resistance of the transgenic rice to blast had a greater improvement than that of the corresponding recurrent parents or the corresponding check hybrid combinations. The resistance of the advanced backcross and selfed generations to rice blast is much stronger than that of the early generations. The study confirmed thattransferring the lysozyme gene into hybrid parents by backcrossing was a simple and effective approach to develop new hybrid rice resistant to rice blast.

  8. Curcumin and kaempferol prevent lysozyme fibril formation by modulating aggregation kinetic parameters.

    Science.gov (United States)

    Borana, Mohanish S; Mishra, Pushpa; Pissurlenkar, Raghuvir R S; Hosur, Ramakrishna V; Ahmad, Basir

    2014-03-01

    Interaction of small molecule inhibitors with protein aggregates has been studied extensively, but how these inhibitors modulate aggregation kinetic parameters is little understood. In this work, we investigated the ability of two potential aggregation inhibiting drugs, curcumin and kaempferol, to control the kinetic parameters of aggregation reaction. Using thioflavin T fluorescence and static light scattering, the kinetic parameters such as amplitude, elongation rate constant and lag time of guanidine hydrochloride-induced aggregation reactions of hen egg white lysozyme were studied. We observed a contrasting effect of inhibitors on the kinetic parameters when aggregation reactions were measured by these two probes. The interactions of these inhibitors with hen egg white lysozyme were investigated using fluorescence quench titration method and molecular dynamics simulations coupled with binding free energy calculations. We conclude that both the inhibitors prolong nucleation of amyloid aggregation through binding to region of the protein which is known to form the core of the protein fibril, but once the nucleus is formed the rate of elongation is not affected by the inhibitors. This work would provide insight into the mechanism of aggregation inhibition by these potential drug molecules. Copyright © 2014 Elsevier B.V. All rights reserved.

  9. Aggregation behavior of novel heptamethine cyanine dyes upon their binding to native and fibrillar lysozyme.

    Science.gov (United States)

    Vus, Kateryna; Tarabara, Ulyana; Kurutos, Atanas; Ryzhova, Olga; Gorbenko, Galyna; Trusova, Valeriya; Gadjev, Nikolai; Deligeorgiev, Todor

    2017-04-05

    Two newly synthesized symmetrical heptamethine cyanine dyes, AK7-5 and AK7-6, absorbing in the region of low autofluorescence of biological samples, have been tested for their ability to detect proteins aggregated into amyloid fibrils. In aqueous solution these probes possess three absorption bands corresponding to the monomer, dimer and H-aggregate species. The association of the dye with fibrillar lysozyme was followed by the enhancement of the monomer band and the reduction of the H-band. The absorption spectra measured at various fibril concentrations were analyzed in terms of the model allowing for the shift of equilibria between various dye species due to the binding of monomers and dimers of AK7-5 and AK7-6 to amyloid fibrils. The association constants and stoichiometries of the dye-fibril complexation have been evaluated. In contrast to fibrillar lysozyme, the native protein brought about strong J-aggregate formation accompanied by a marked drop in the absorbance of the dye monomer species. Quantum chemical calculations and simple docking studies showed that AK7-5 and AK7-6 monomers can bind to the grooves, running parallel to the fibril axis. Due to their ability to distinguish between the native and fibrillar protein states, the novel cyanines are recommended as complementary to existing amyloid markers.

  10. The disinfection performance and mechanisms of Ag/lysozyme nanoparticles supported with montmorillonite clay.

    Science.gov (United States)

    Jiang, Jing; Zhang, Chang; Zeng, Guang-Ming; Gong, Ji-Lai; Chang, Ying-Na; Song, Biao; Deng, Can-Hui; Liu, Hong-Yu

    2016-11-05

    The fabrication of montmorillonite (Mt) decorated with lysozyme-modified silver nanoparticles (Ag/lyz-Mt) was reported. The lysozyme (lyz) was served as both reducing and capping reagent. Coupling the bactericidal activity of the lyz with AgNPs, along with the high porous structure and large specific surface area of the Mt, prevented aggregation of AgNPs and promoted nanomaterial-bacteria interactions, resulting in a greatly enhanced bactericidal capability against both Gram positive and Gram negative bacteria. This paper systematically elucidated the bactericidal mechanisms of Ag/lyz-Mt. Direct contact between the Ag/lyz-Mt surface and the bacterial cell was essential to the disinfection. Physical disruption of bacterial membrane was considered to be one of the bactericidal mechanisms of Ag/lyz-Mt. Results revealed that Ag(+) was involved in the bactericidal activity of Ag/lyz-Mt via tests conducted using Ag(+) scavengers. A positive ROS (reactive oxygen species) scavenging test indirectly confirmed the involvement of ROS (O2(-), H2O2, and OH) in the bactericidal mechanism. Furthermore, the concentrations of individual ROS were quantified. Results showed that Ag/lyz-Mt nanomaterial could be a promising bactericide for water disinfection.

  11. Effect of cholesterol on the properties of spray-dried lysozyme-loaded liposomal powders.

    Science.gov (United States)

    Charnvanich, Dusadee; Vardhanabhuti, Nontima; Kulvanich, Poj

    2010-06-01

    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 respect to morphology, thermal property, and crystallinity using scanning electron microscopy, differential scanning calorimetry, and X-ray diffraction, respectively. Most formulations gave slightly aggregated, spherical particles, and percentage yields of the spray-dried powders decreased with increasing Chol content. Degree of particle aggregation depended on the powder composition. The powders spontaneously formed liposomes which efficiently entrapped LSZ after reconstitution with HEPES buffered saline (HBS) at 37 degrees C. Lysozyme entrapment efficiency and size distribution of the reconstituted liposomes were evaluated after the powders were reconstituted with HBS. Increasing Chol content resulted in a decrease in size of the reconstituted liposomes and an increase in entrapment efficiency of LSZ. These results correlated with thermal behaviors of the reconstituted liposomes. Biological activity of LSZ was not affected by the spray-drying process. It was also demonstrated that LSZ-loaded liposomal powders could be produced without the need to preload the LSZ into liposomes prior to spray-drying process.

  12. Analysis of raw goat milk microbiota: impact of stage of lactation and lysozyme on microbial diversity.

    Science.gov (United States)

    McInnis, Elizabeth A; Kalanetra, Karen M; Mills, David A; Maga, Elizabeth A

    2015-04-01

    To protect infants from infection, human milk contains high levels of the enzyme lysozyme, unlike the milk of dairy animals. We have genetically engineered goats to express human lysozyme (hLZ milk) in their milk at 68% the amount found in human milk to help extend this protection. This study looked at the effect of hLZ on bacteria in raw milk over time. As the microbial diversity of goats' milk has yet to be investigated in depth using next-generation sequencing (NGS) technologies, we applied NGS and clone library sequencing (CLS) to determine the microbiota of raw goat milk (WT milk) and hLZ milk at early, mid and late lactation. Overall, in WT milk, the bacterial populations in milk at early and mid lactation were similar to each other with a shift occurring at late lactation. Both methods found Proteobacteria as the dominant bacteria at early and mid lactation, while Actinobacteria surged at late lactation. These changes were related to decreases in Pseudomonas and increases in Micrococcus. The bacterial populations in hLZ milk were similar to WT milk at early and mid lactation with the only significant differences occurring at late lactation with the elevation of Bacillaceae, Alicyclobacillaceae, Clostridiaceae and Halomonadaceae.

  13. The Effect of Solution Parameters on Lysozyme Nucleation Rates and Crystal Quality

    Science.gov (United States)

    Judge, R. A.; Snell, E. H.

    1998-01-01

    In the pursuit of strongly diffracting high quality macromolecule crystals of suitable volume, this study investigates how the formation of macromolecules in solution and their growth characteristics effect crystal volume and diffracting quality. We systematically investigated the effect of solution conditions on lysozyme nucleation rates and the volume of crystals produced. Batch crystallization plates were used in combination with a video microscope system to measure nucleation rates and crystal volume. As expected from classical nucleation theory, crystal numbers were found to increase with increases in temperature and supersaturation. Small changes in solution pH, at constant supersaturation values were found, however, to dramatically effect the number of crystals nucleated in the wells varying from 1000s to 10s in the pH range 4.0 to 5.2. Having optimized the conditions required to produce an appropriate number of crystals of a suitable volume for X-ray analysis, a large number of uniform crystals were produced under exactly the same conditions. In the X-ray analysis of more than 50 such crystals there was found a wide variation in crystal lattice parameters and data quality. The variation in X-ray quality crystal samples is thought to be related to the growth rate variation caused by growth rate dispersion seen in lysozyme crystal growth experiments.

  14. Carnosine's effect on amyloid fibril formation and induced cytotoxicity of lysozyme.

    Directory of Open Access Journals (Sweden)

    Josephine W Wu

    Full Text Available Carnosine, a common dipeptide in mammals, has previously been shown to dissemble alpha-crystallin amyloid fibrils. To date, the dipeptide's anti-fibrillogensis effect has not been thoroughly characterized in other proteins. For a more complete understanding of carnosine's mechanism of action in amyloid fibril inhibition, we have investigated the effect of the dipeptide on lysozyme fibril formation and induced cytotoxicity in human neuroblastoma SH-SY5Y cells. Our study demonstrates a positive correlation between the concentration and inhibitory effect of carnosine against lysozyme fibril formation. Molecular docking results show carnosine's mechanism of fibrillogenesis inhibition may be initiated by binding with the aggregation-prone region of the protein. The dipeptide attenuates the amyloid fibril-induced cytotoxicity of human neuronal cells by reducing both apoptotic and necrotic cell deaths. Our study provides solid support for carnosine's amyloid fibril inhibitory property and its effect against fibril-induced cytotoxicity in SH-SY5Y cells. The additional insights gained herein may pave way to the discovery of other small molecules that may exert similar effects against amyloid fibril formation and its associated neurodegenerative diseases.

  15. Form of presentation, natural history and course of postoperative venous thromboembolism in patients operated on for pelvic and abdominal cancer. Analysis of the RIETE registry.

    Science.gov (United States)

    Bustos Merlo, Ana Belén; Arcelus Martínez, Juan Ignacio; Turiño Luque, Jesús Damián; Valero, Beatriz; Villalobos, Aurora; Aibar, Miguel Ángel; Monreal Bosch, Manuel

    Venous thromboembolism (VTE) represents a serious complication after oncologic surgery. Recent studies have shown that the risk of VTE persists several weeks after surgery. This study assesses the form of presentation and time course of VTE after abdominal and pelvic cancer surgery. Prospective, multicenter, observational study that analyzes data from an international registry (RIETE) that includes consecutive patients with symptomatic VTE. Our study assesses the form and time of presentation of postoperative VTE, as well as main outcomes, in patients operated for abdominopelvic cancer 8 weeks prior to VTE diagnosis. Variables related to the presentation of VTE after hospital discharge are identified. Out of the 766 analyzed patients with VTE, 395 (52%) presented pulmonary embolism (PE). Most VTE cases (84%) were detected after the first postoperative week, and 38% after one month. Among patients with VTE in the first postoperative week, 70% presented PE. VTE presented after hospital discharge in 54% of cases. Colorectal, urologic, and gynecologic tumors, the use of radiotherapy, and blood hemoglobin levels were independently associated with VTE diagnosis after hospital discharge. Complications (thrombosis recurrence, bleeding, and death) occurred in 34% of patients with VTE detected before hospital discharge, compared to 24% in VTE after hospital discharge (P<0.01). VTE occurs after hospital discharge in most patients, particularly in those operated for colorectal, urologic, and gynecologic cancer. Pulmonary embolism is more frequent in patients who develop early VTE, who also have worse prognosis. Copyright © 2017 AEC. Publicado por Elsevier España, S.L.U. All rights reserved.

  16. 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

  17. Efficacy and safety of sarolaner (Simparica(®)) in the treatment and control of naturally occurring flea infestations in dogs presented as veterinary patients in Australia.

    Science.gov (United States)

    Packianathan, Raj; Colgan, Sally; Hodge, Andrew; Davis, Kylie; Six, Robert H; Maeder, Steven

    2017-08-16

    The efficacy and safety of a novel isoxazoline compound, sarolaner (Simparica(®), Zoetis) and spinosad (Comfortis(®), Elanco) as a positive control were evaluated for the treatment and control of natural flea infestations on dogs in two randomised, blinded, multi-centric clinical trials conducted in 11 veterinary clinics in northeastern and southeastern states of Australia. A total of 162 client-owned dogs (80 in northern study and 82 in southern study) from 105 households were enrolled. Each household was randomly allocated to receive either sarolaner (Simparica(®), Zoetis) or spinosad (Comfortis(®), Elanco). Dogs were dosed on Days 0, 30 and 60 and physical examinations and flea counts were conducted on Days 0, 14, 30, 60 and 90. Efficacy assessments were based on the percentage reduction in live flea counts post-treatment compared to Day 0. In the northern study, at enrolment, primary dogs had flea counts ranging from 5 to 772. At the first efficacy assessment on Day 14, sarolaner resulted in 99.3% mean reduction in live flea counts relative to Day 0, compared to 94.6% in the spinosad group. On Day 30, the sarolaner-treated group had mean efficacy of 99.2% compared to 95.7% in the spinosad-treated group, and on days 60 and 90, both groups had mean efficacies of ≥ 98.8%. In the southern study, at enrolment, primary dogs had flea counts ranging from 5 to 156. Both sarolaner and spinosad resulted in ≥ 96.7% mean reduction in live flea counts on Day 14. On Day 30, the sarolaner-treated group had mean efficacy of 99.5% compared to 89.7% in the spinosad-treated group, and on days 60 and 90, both groups had mean efficacies of ≥ 98.6%. No treatment-related adverse events were observed in either study. A single monthly dose of sarolaner (Simparica(®)) administered orally at 2-4 mg/kg for three consecutive months was well tolerated and provided excellent efficacy against natural infestations of fleas under a range of Australian field conditions including

  18. Functional and structural analysis of the internal ribosome entry site present in the mRNA of natural variants of the HIV-1.

    Science.gov (United States)

    Vallejos, Maricarmen; Carvajal, Felipe; Pino, Karla; Navarrete, Camilo; Ferres, Marcela; Huidobro-Toro, Juan Pablo; Sargueil, Bruno; López-Lastra, Marcelo

    2012-01-01

    The 5'untranslated regions (UTR) of the full length mRNA of the HIV-1 proviral clones pNL4.3 and pLAI, harbor an internal ribosomal entry site (IRES). In this study we extend this finding by demonstrating that the mRNA 5'UTRs of natural variants of HIV-1 also exhibit IRES-activity. Cap-independent translational activity was demonstrated using bicistronic mRNAs in HeLa cells and in Xenopus laevis oocytes. The possibility that expression of the downstream cistron in these constructs was due to alternative splicing or to cryptic promoter activity was ruled out. The HIV-1 variants exhibited significant 5'UTR nucleotide diversity with respect to the control sequence recovered from pNL4.3. Interestingly, translational activity from the 5'UTR of some of the HIV-1 variants was enhanced relative to that observed for the 5'UTR of pNL4.3. In an attempt to explain these findings we probed the secondary structure of the variant HIV-1 5'UTRs using enzymatic and chemical approaches. Yet subsequent structural analyses did not reveal significant variations when compared to the pNL4.3-5'UTR. Thus, the increased IRES-activity observed for some of the HIV-1 variants cannot be ascribed to a specific structural modification. A model to explain these findings is proposed.

  19. Functional and structural analysis of the internal ribosome entry site present in the mRNA of natural variants of the HIV-1.

    Directory of Open Access Journals (Sweden)

    Maricarmen Vallejos

    Full Text Available The 5'untranslated regions (UTR of the full length mRNA of the HIV-1 proviral clones pNL4.3 and pLAI, harbor an internal ribosomal entry site (IRES. In this study we extend this finding by demonstrating that the mRNA 5'UTRs of natural variants of HIV-1 also exhibit IRES-activity. Cap-independent translational activity was demonstrated using bicistronic mRNAs in HeLa cells and in Xenopus laevis oocytes. The possibility that expression of the downstream cistron in these constructs was due to alternative splicing or to cryptic promoter activity was ruled out. The HIV-1 variants exhibited significant 5'UTR nucleotide diversity with respect to the control sequence recovered from pNL4.3. Interestingly, translational activity from the 5'UTR of some of the HIV-1 variants was enhanced relative to that observed for the 5'UTR of pNL4.3. In an attempt to explain these findings we probed the secondary structure of the variant HIV-1 5'UTRs using enzymatic and chemical approaches. Yet subsequent structural analyses did not reveal significant variations when compared to the pNL4.3-5'UTR. Thus, the increased IRES-activity observed for some of the HIV-1 variants cannot be ascribed to a specific structural modification. A model to explain these findings is proposed.

  20. Cyclic lipodepsipeptides produced by Pseudomonas spp. naturally present in raw milk induce inhibitory effects on microbiological inhibitor assays for antibiotic residue screening.

    Directory of Open Access Journals (Sweden)

    Wim Reybroeck

    Full Text Available Two Pseudomonas strains, identified as closely related to Pseudomonas tolaasii, were isolated from milk of a farm with frequent false-positive Delvotest results for screening putative antibiotic residues in raw milk executed as part of the regulatory quality programme. Growth at 5 to 7°C of these isolates in milk resulted in high lipolysis and the production of bacterial inhibitors. The two main bacterial inhibitors have a molecular weight of 1168.7 and 1140.7 Da respectively, are heat-tolerant and inhibit Geobacillus stearothermophilus var. calidolactis, the test strain of most of the commercially available microbiological inhibitor tests for screening of antibiotic residues in milk. Furthermore, these bacterial inhibitors show antimicrobial activity against Staphylococcus aureus, Bacillus cereus and B. subtilis and also interfere negatively with yoghurt production. Following their isolation and purification with RP-HPLC, the inhibitors were identified by NMR analysis as cyclic lipodepsipeptides of the viscosin group. Our findings bring to light a new challenge for quality control in the dairy industry. By prolonging the refrigerated storage of raw milk, the keeping quality of milk is influenced by growth and metabolic activities of psychrotrophic bacteria such as pseudomonads. Besides an increased risk of possible spoilage of long shelf-life milk, the production at low temperature of natural bacterial inhibitors may also result in false-positive results for antibiotic residue screening tests based on microbial inhibitor assays thus leading to undue production loss.

  1. Correlation of Conformational Changes and Protein Degradation with Loss of Lysozyme Activity Due to Chlorine Dioxide Treatment.

    Science.gov (United States)

    Ooi, Beng Guat; Branning, Sharon Alyssa

    2016-12-13

    Chlorine dioxide (ClO2) is a potent oxidizing agent used for the treatment of drinking water and decontamination of facilities and equipment. The purpose of this research is to elucidate the manner in which ClO2 destroys proteins by studying the effects of ClO2 on lysozyme. The degree of enzyme activity lost can be correlated to the treatment time and levels of the ClO2 used. Lysozyme activity was drastically reduced to 45.3% of original enzyme activity when exposed to 4.3 mM ClO2 in the sample after 3 h. Almost all activities were lost in 3 h after exposure to higher ClO2 concentrations of up to 16.8 and 21.9 mM. Changes in protein conformation and amount as a result of ClO2 treatment were determined using the Raman spectroscopy and gel electrophoresis. Raman shifts and the alteration of spectral features observed in the ClO2-treated lysozyme samples are associated with loss of the α-helix secondary structure, tertiary structure, and disulfide bond. Progressive degradation of the denatured lysozyme by increasing levels of chlorine dioxide was also observed in gel electrophoresis. Hence, ClO2 can effectively cause protein denaturation and degradation resulting in loss of enzyme activity.

  2. Destruction of single-species biofilms of Escherichia coli or Klebsiella pneumoniae subsp. pneumoniae by dextranase, lactoferrin, and lysozyme

    Science.gov (United States)

    The activity of dextranase, lactoferrin, lysozyme, and nisin against biofilms composed of either Klebsiella pneumonia or Escherichia coli was examined using the MBEC Assay™. Mature biofilms were treated and then sonicated to remove the adherent biofilm. This material was quantified using a lumines...

  3. Impact of salivary flow and lysozyme content and output on the oral health of rheumatoid arthritis patients

    Directory of Open Access Journals (Sweden)

    Anna Zalewska

    2011-01-01

    Full Text Available Purpose:The aim of the study was to examine salivary flow rate, DMF index, lysozyme concentration and its output in two groups of rheumatoid patients and to compare the results with those of healthy controls.Material/Methods:Rheumatoid arthritis (RA patients were divided into two study groups: with reduced salivary flow rate ≤0.15 ml/min (RA HS, hyposalivation and with normal salivary secretion rate >0.2 ml/min (RA NS, normal salivation. The healthy control group (C was recruited from the Department of Conservative Dentistry. Salivary lysozyme concentration was determined by radial immunodiffusion. ANOVA followed by LSD test were used for the statistical analysis.Results:We found that lysozyme concentration was higher and lysozyme output and salivary flow rate were statistically lower in the RA HS group in comparison to the RA NS and C groups. The DMF index was statistically higher in both RA groups in comparison to the control group.Conclusions:RA disease impacts negatively on oral health and salivary parameters. Hyposalivation of RA patients increases the negative influence of RA on oral health. RA patients should receive more stomatological attention.

  4. Impact of salivary flow and lysozyme content and output on the oral health of rheumatoid arthritis patients.

    Science.gov (United States)

    Zalewska, Anna; Waszkiewicz, Napoleon; Szajda, Sławomir Dariusz; Waszkiel, Danuta

    2011-02-01

    The aim of the study was to examine salivary flow rate, DMF index, lysozyme concentration and its output in two groups of rheumatoid patients and to compare the results with those of healthy controls. Rheumatoid arthritis (RA) patients were divided into two study groups: with reduced salivary flow rate ≤0.15 ml/min (RA HS, hyposalivation) and with normal salivary secretion rate >0.2 ml/min (RA NS, normal salivation). The healthy control group (C) was recruited from the Department of Conservative Dentistry. Salivary lysozyme concentration was determined by radial immunodiffusion. ANOVA followed by LSD test were used for the statistical analysis. We found that lysozyme concentration was higher and lysozyme output and salivary flow rate were statistically lower in the RA HS group in comparison to the RA NS and C groups. The DMF index was statistically higher in both RA groups in comparison to the control group. RA disease impacts negatively on oral health and salivary parameters. Hyposalivation of RA patients increases the negative influence of RA on oral health. RA patients should receive more stomatological attention.

  5. Immobilization of lysozyme-cellulose amide-linked conjugates on cellulose i and ii cotton nanocrystalline preparations

    Science.gov (United States)

    Lysozyme was attached through an amide linkage between some of the protein’s aspartate and glutamate residues to amino-glycine-cellulose (AGC), which was prepared by esterification of glycine to preparations of cotton nanocrystals (CNC). The nanocrystalline preparations were produced through acid h...

  6. CRYSTAL-STRUCTURES OF HEVAMINE, A PLANT DEFENSE PROTEIN WITH CHITINASE AND LYSOZYME ACTIVITY, AND ITS COMPLEX WITH AN INHIBITOR

    NARCIS (Netherlands)

    VANSCHELTINGA, ACT; KALK, KH; BEINTEMA, JJ; DIJKSTRA, BW

    1994-01-01

    Background: Hevamine is a member of one of several families of plant chitinases and lysozymes that are important for plant defence against pathogenic bacteria and fungi. The enzyme can hydrolyze the linear polysaccharide chains of chitin and peptidoglycan. A full understanding of the structure/funct

  7. Effect of lysozyme or nisin on survival of some bacteria treated with high pressure at subzero temperature

    Directory of Open Access Journals (Sweden)

    Edyta Malinowska-Pańczyk

    2009-12-01

    Full Text Available The aim of this work was to examine the inactivation of some Gram-positive and Gram-negative bacteria exposed to the pressure of 193 MPa at -20 °C in the presence of lysozyme or nisin at concentration of 400 mg/ml. The highest effect of pressure at subzero temperature and lysozyme was found with pressure sensitive Pseudomonas fluorescens; viable cells of this strain were not detected in 1 ml of sample after combined treatment. The action of pressure at subzero temperature and lysozyme or nisin against Escherichia coli led to synergistic reduction by 0.7 or 1.6 log cycles, respectively, while it was practically insignificant for two Staphylococcus aureus strains. Viability loss of E. coli and S. aureus occurred during storage for 20 h of the samples at 37 and 5 °C, which were previously pressurized with lysozyme or nisin. The synergistic effect of pressure and nisin at pH 5 against E. coli cells just after the pressure treatment was lower than that at pH 7, however, the extent of the lethal effect after storage was higher.

  8. Effects of mannose, fructose, and fucose on the structure, stability, and hydration of lysozyme in aqueous solution

    DEFF Research Database (Denmark)

    Rahim, Abdoul; Peters, Günther H.J.; Jalkanen, Karl J.

    2013-01-01

    The bio-protective properties of monosaccharaides, namely mannose, fructose and fucose, on the stability and dynamical properties of the NMR determined hen egg-white lysozyme structure have been investigated by means of molecular dynamics simulations at room temperature in aqueous solution and in...

  9. Direct Biomolecules Binding on Nonfouling Surface via Newly Discovered Supramolecular Self-assembly of Lysozyme under Physiological Condition

    Science.gov (United States)

    Yang, Peng

    2013-01-01

    A major challenge in the development of low cost and practical strategies for biomolecules immobilization on solid supports is that the multi-step chemical/physical activating and following deactivating procedures on nonfouling substrates often increase the cost and complexity of surface functional group types as well as deteriorate the surface integrity. Herein, we show a novel phase transition of lysozyme could be used to constitute a major step to address the above problem. It is found that when lysozyme is dissolved in a neutral buffer solution of 4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid (HEPES, pH 7.4) with 1–50 mM tris(2-carboxyethyl)phosphine (TCEP) added, a fast phase transition process occurs and the resulting novel fibra-like hierarchical supramolecular assemblies made by primary spherical particles aggregation would function as a “superglue” that strongly and quickly bind onto non-fouling coatings. This binding is highly selective towards lysozyme, and excludes completely tedious synthetical, chemical/physical activation/deactivation (blocking) steps. When biotin is conjugated with lysozyme, such phase transition quickly constructs a perfect biotinylated surface on nonfouling surface for avidin binding, showing great potential for the development of low-cost and practical biochips. PMID:22707360

  10. Factors controlling present-day tufa dynamics in the Monasterio de Piedra Natural Park (Iberian Range, Spain): depositional environmental settings, sedimentation rates and hydrochemistry

    Science.gov (United States)

    Vázquez-Urbez, M.; Arenas, C.; Sancho, C.; Osácar, C.; Auqué, L.; Pardo, G.

    2010-07-01

    The tufa record and hydrochemical characteristics of the River Piedra in the Monasterio de Piedra Natural Park (NE Spain) were studied for 6 years. The mean discharge of this river was 1.22 m3/s. The water was supersaturated with calcium carbonate. The HCO3 -, Ca2+ and TDIC concentrations decreased along the 0.5-km-long studied stretch, whereas the calcite SI showed no systematic downstream or seasonal variation over the same stretch. Several sedimentary subenvironments exist in which four broad types of tufa facies form: (1) Dense laminated tufa (stromatolites), (2) Dense to porous, massive tufa, (3) Porous, coarsely laminated tufa with bryophytes and algae, and (4) Dense, hard, laminated deposits in caves. The half-yearly period thickness and weight of sediment accumulated on 14 tablets installed in several subenvironments showed that the deposition rate was greater in fast flowing river areas and in stepped waterfalls, and lower in slow flowing or standing river areas and in spray and splash areas. Mechanical CO2 outgassing is the main factor controlling calcite precipitation on the river bed and in waterfalls, but this process does not explain the seasonal changes in depositional rates. The deposition rates showed a half-yearly period pattern recorded in all fluvial subenvironments persistent over time (5.26 mm, 0.86 g/cm2 in warm periods; 2.26 mm, 0.13 g/cm2 in cool periods). Mass balance calculations showed higher calcite mass values in warm (21.58 mg/L) than in cool (13.68 mg/L) periods. This biannual variation is mainly attributed to the seasonal differences in temperature that caused changes in inorganic calcite precipitation rate and in biomass and the correlative photosynthetic activity. Tufa sedimentation was therefore controlled by both physicochemical and biological processes. The results of this study may help test depositional rates and their environmental controls and thus assess the climatic and hydrological significance of ancient tufas in semi

  11. Papel de los esteroles vegetales presentes de forma natural en la dieta sobre la absorción intestinal de colesterol y sus niveles plasmáticos

    OpenAIRE

    Sanclemente Hernández, Teresa Mª; Marques Lopes, Iva; Puzo Foncillas, José

    2011-01-01

    Modular la absorción intestinal de colesterol es una forma potencialmente efectiva de disminuir los niveles sanguíneos de colesterol y el riesgo cardiovascular inherente en la población general. La eficacia de absorción puede modificarse mediante la ingesta de alimentos enriquecidos con fitoesteroles pero poco se conoce sobre los efectos de las cantidades presentes naturalmente en la dieta habitual aunque se ha descrito que dosis moderadas afectan al metabolismo corporal de colesterol. El obj...

  12. Papel de los esteroles vegetales presentes de forma natural en la dieta sobre la absorción intestinal de colesterol y sus niveles plasmáticos

    OpenAIRE

    Sanclemente Hernández, Teresa Mª; Marques Lopes, Iva; Puzo Foncillas, José

    2011-01-01

    Modular la absorción intestinal de colesterol es una forma potencialmente efectiva de disminuir los niveles sanguíneos de colesterol y el riesgo cardiovascular inherente en la población general. La eficacia de absorción puede modificarse mediante la ingesta de alimentos enriquecidos con fitoesteroles pero poco se conoce sobre los efectos de las cantidades presentes naturalmente en la dieta habitual aunque se ha descrito que dosis moderadas afectan al metabolismo corporal de colesterol. El obj...

  13. Serum Amyloid P Component Ameliorates Neurological Damage Caused by Expressing a Lysozyme Variant in the Central Nervous System of Drosophila melanogaster.

    Directory of Open Access Journals (Sweden)

    Linda Helmfors

    Full Text Available Lysozyme amyloidosis is a hereditary disease in which mutations in the gene coding for lysozyme leads to misfolding and consequently accumulation of amyloid material. To improve understanding of the processes involved we expressed human wild type (WT lysozyme and the disease-associated variant F57I in the central nervous system (CNS of a Drosophila melanogaster model of lysozyme amyloidosis, with and without co-expression of serum amyloid p component (SAP. SAP is known to be a universal constituent of amyloid deposits and to associate with lysozyme fibrils. There are clear indications that SAP may play an important role in lysozyme amyloidosis, which requires further elucidation. We found that flies expressing the amyloidogenic variant F57I in the CNS have a shorter lifespan than flies expressing WT lysozyme. We also identified apoptotic cells in the brains of F57I flies demonstrating that the flies' neurological functions are impaired when F57I is expressed in the nerve cells. However, co-expression of SAP in the CNS prevented cell death and restored the F57I flies' lifespan. Thus, SAP has the apparent ability to protect nerve cells from damage caused by F57I. Furthermore, it was found that co-expression of SAP prevented accumulation of insoluble forms of lysozyme in both WT- and F57I-expressing flies. Our findings suggest that the F57I mutation affects the aggregation process of lysozyme resulting in the formation of cytotoxic species and that SAP is able to prevent cell death in the F57I flies by preventing accumulation of toxic F57I structures.

  14. REMOCIÓN DE MICROORGANISMOS PATÓGENOS PRESENTES EN UN LICOR MIXTO BAJO CONDICIONES DE LABORATORIO EMPLEANDO FILTROS EMPACADOS EN ZEOLITA NATURAL REMOVAL OF PATHOGENIC MICROORGANISMS PRESENT IN MIXED LIQUOUR UNDER LABORATORY CONDITIONS BY USING FILTERS PACKED IN NATURAL ZEOLITE

    Directory of Open Access Journals (Sweden)

    Diana Rocío Acevedo Cifuentes

    2012-12-01

    Full Text Available En este artículo, se presentan los resultados obtenidos en la remoción de coliformes totales, coliformes fecales y salmonella-shigella, presentes en un licor mixto proveniente de la planta de tratamiento de aguas residuales San Fernando (Medellín, Colombia, mediante el uso de una batería de filtros empacados en zeolita clinoptilolita. La experimentación se desarrolló bajo condiciones controladas de caudal y pH, a temperatura ambiente. Se empleó zeolita natural tipo clinoptilolita la cual se activó con solución salina y secado, se empacó en una batería compuesta por dos filtros, uno de flujo descendente y otro de flujo ascendente, para facilitar el contacto de la solución contaminada y el material adsorbente (zeolita. Se realizaron cinco ensayos independientes y al final de cada uno de ellos se lavó y se activó el material zeolítico antes de comenzar el siguiente. En cada ensayo se tomaron tres muestras. Se encontró que la eficiencia de los filtros bajo las condiciones específicas de diseño fue significativamente alta en la remoción de los patógenos evaluados, y el porcentaje de remoción fue independiente del valor de la concentración a la entrada del filtro. Además, la eficiencia en la remoción de los patógenos evaluados no dependió del tipo de microorganismo.This article displays results obtained when total coliforms, fecal coliforms, and Salmonella shigella were removed from mixed liquor taken from San Fernando waste water treatment plant in Medellín, Colombia, by using a battery of filters packed in zeolite clinoptilolite. Experiments were developed under controlled conditions of flow and pH at room temperature. Natural clinoptilolite-type zeolite was used activated with saline solution and drying; it was packed in a battery consisting of two filters (a downward-flow filter and an upward-flow filter in order to make contact of contaminated solution and adsorbent material (zeolite easier. Five independent tests were

  15. Biological activities of Schottenol and Spinasterol, two natural phytosterols present in argan oil and in cactus pear seed oil, on murine miroglial BV2 cells.

    Science.gov (United States)

    El Kharrassi, Youssef; Samadi, Mohammad; Lopez, Tatiana; Nury, Thomas; El Kebbaj, Riad; Andreoletti, Pierre; El Hajj, Hammam I; Vamecq, Joseph; Moustaid, Khadija; Latruffe, Norbert; El Kebbaj, M'Hammed Saïd; Masson, David; Lizard, Gérard; Nasser, Boubker; Cherkaoui-Malki, Mustapha

    2014-04-11

    The objective of this study was to evaluate the biological activities of the major phytosterols present in argan oil (AO) and in cactus seed oil (CSO) in BV2 microglial cells. Accordingly, we first determined the sterol composition of AO and CSO, showing the presence of Schottenol and Spinasterol as major sterols in AO. While in CSO, in addition to these two sterols, we found mainly another sterol, the Sitosterol. The chemical synthesis of Schottenol and Spinasterol was performed. Our results showed that these two phytosterols, as well as sterol extracts from AO or CSO, are not toxic to microglial BV2 cells. However, treatments by these phytosterols impact the mitochondrial membrane potential. Furthermore, both Schottenol and Spinasterol can modulate the gene expression of two nuclear receptors, liver X receptor (LXR)-α and LXRβ, their target genes ABCA1 and ABCG1. Nonetheless, only Schottenol exhibited a differential activation vis-à-vis the nuclear receptor LXRβ. Thus Schottenol and Spinasterol can be considered as new LXR agonists, which may play protective roles by the modulation of cholesterol metabolism. Copyright © 2014 Elsevier Inc. All rights reserved.

  16. Biological activities of Schottenol and Spinasterol, two natural phytosterols present in argan oil and in cactus pear seed oil, on murine miroglial BV2 cells

    Energy Technology Data Exchange (ETDEWEB)

    El Kharrassi, Youssef [Université de Bourgogne, Laboratoire Bio-PeroxIL, EA7270, Dijon F-21000 (France); Laboratoire de Biochimie et Neurosciences, Faculté des Sciences et Techniques, Université Hassan I, BP 577, 26000 Settat (Morocco); Samadi, Mohammad [LCPMC-A2, ICPM, Department of Chemistry, Université de Lorraine, Metz (France); Lopez, Tatiana [CRINSERM 866, Dijon (France); Nury, Thomas [Université de Bourgogne, Laboratoire Bio-PeroxIL, EA7270, Dijon F-21000 (France); El Kebbaj, Riad [Université de Bourgogne, Laboratoire Bio-PeroxIL, EA7270, Dijon F-21000 (France); Laboratoire de Biochimie et Neurosciences, Faculté des Sciences et Techniques, Université Hassan I, BP 577, 26000 Settat (Morocco); Andreoletti, Pierre; El Hajj, Hammam I. [Université de Bourgogne, Laboratoire Bio-PeroxIL, EA7270, Dijon F-21000 (France); Vamecq, Joseph [INSERM and HMNO, CBP, CHRU Lille, 59037 Lille (France); Moustaid, Khadija [Laboratoire de Biochimie et Neurosciences, Faculté des Sciences et Techniques, Université Hassan I, BP 577, 26000 Settat (Morocco); Latruffe, Norbert [Université de Bourgogne, Laboratoire Bio-PeroxIL, EA7270, Dijon F-21000 (France); El Kebbaj, M’Hammed Saïd [Laboratoire de recherche sur les Lipoprotéines et l’Athérosclérose, Faculté des Sciences Ben M’sik, Avenue Cdt Driss El Harti BP. 7955, Université Hassan II-Mohammedia-Casablanca (Morocco); Masson, David [CRINSERM 866, Dijon (France); and others

    2014-04-11

    Highlights: • Sterol composition in argan oil and in cactus seed oil. • Chemical synthesis of two sterols: Schottenol and Spinasterol. • Sterols from argan oil or from cactus seed oil show no toxicity on BV2 cells. • Schottenol and Spinasterol modulate the activation and the expression of two nuclear receptors, LXRα and LXRβ. - Abstract: The objective of this study was to evaluate the biological activities of the major phytosterols present in argan oil (AO) and in cactus seed oil (CSO) in BV2 microglial cells. Accordingly, we first determined the sterol composition of AO and CSO, showing the presence of Schottenol and Spinasterol as major sterols in AO. While in CSO, in addition to these two sterols, we found mainly another sterol, the Sitosterol. The chemical synthesis of Schottenol and Spinasterol was performed. Our results showed that these two phytosterols, as well as sterol extracts from AO or CSO, are not toxic to microglial BV2 cells. However, treatments by these phytosterols impact the mitochondrial membrane potential. Furthermore, both Schottenol and Spinasterol can modulate the gene expression of two nuclear receptors, liver X receptor (LXR)-α and LXRβ, their target genes ABCA1 and ABCG1. Nonetheless, only Schottenol exhibited a differential activation vis-à-vis the nuclear receptor LXRβ. Thus Schottenol and Spinasterol can be considered as new LXR agonists, which may play protective roles by the modulation of cholesterol metabolism.

  17. Raman study of lysozyme amyloid fibrils suspended on super-hydrophobic surfaces by shear flow

    KAUST Repository

    Moretti, Manola

    2017-05-19

    The shear flow generated at the rim of a drop evaporating on a micro-fabricated super-hydrophobic surface has been used to suspend and orient single/few lysozyme amyloid fibrils between two pillars for substrate-free characterization. Micro Raman spectroscopy performed on extended fibers evidenced a shift of the Amide I band main peak to the value attributed to β-sheet secondary structure, characteristic of the amyloid fibers. In addition, given the orientation sensitivity of the anisotropic molecule, the Raman signal of the main secondary structure was nicely enhanced for a fiber alignment parallel to the polarization direction of the laser. The substrate-free sample generated by this suspending technique is suitable for other structural analysis methods, where fiber crystals are investigated. It could be further employed for generation of arrays and patterns in a controllable fashion, where bio-compatible material is needed.

  18. Crystal structure of a shark single-domain antibody V region in complex with lysozyme.

    Science.gov (United States)

    Stanfield, Robyn L; Dooley, Helen; Flajnik, Martin F; Wilson, Ian A

    2004-09-17

    Cartilaginous fish are the phylogenetically oldest living organisms known to possess components of the vertebrate adaptive immune system. Key to their immune response are heavy-chain, homodimeric immunoglobulins called new antigen receptors (IgNARs), in which the variable (V) domains recognize antigens with only a single immunoglobulin domain, akin to camelid heavy-chain V domains. The 1.45 angstrom resolution crystal structure of the type I IgNAR V domain in complex with hen egg-white lysozyme (HEL) reveals a minimal antigen-binding domain that contains only two of the three conventional complementarity-determining regions but still binds HEL with nanomolar affinity by means of a binding interface comparable in size to conventional antibodies.

  19. Binding properties of drospirenone with human serum albumin and lysozyme in vitro

    Science.gov (United States)

    Wang, Qing; Ma, Xiangling; He, Jiawei; Sun, Qiaomei; Li, Yuanzhi; Li, Hui

    2016-01-01

    The interaction of drospirenone (DP) with human serum albumin (HSA)/lysozyme (LYZ) was investigated using different optical techniques and molecular models. Results from the emission and time resolved fluorescence studies revealed that HSA/LYZ emission quenching with DP was initiated by static quenching mechanism. The LYZ-DP system was more easily influenced by temperature than the HSA-DP system. Displacement experiments demonstrated that the DP binding site was mainly located in site 1 of HSA. Based on the docking methods, DP was mainly bound in the active site hinge region where Trp-62 and Trp-63 are located. Conformation study showed that DP had different effects on the local conformation of HSA and LYZ molecules.

  20. New Equation of State for Osmotic Pressures in Aqueous Saline Solutions of Lysozyme

    Institute of Scientific and Technical Information of China (English)

    林阳政; 李以圭; 陆九芳

    2002-01-01

    A new equation of state is proposed to correlate the osmotic pressure data for aqueous lysozyme solutions with (NH4)2SO4, (NH4)2C2O4 and (NH4)2HPO4 at ionic strengths of 13.5 mol/kg and pH 4, 7 or 8 with only one adjustable parameter instead of the classical Derjaguin-Landau-Verwey-Overbeek (DLVO) theory. The Carnahan-Starling equation represents the contribution of the hard sphere repulsion to the osmotic pressure. The attractive dispersion interaction is represented by the Lennard-Jones potential expressed by the equation of Cotterman et al. based on perturbation theory. The double-layer repulsion interaction is represented by Yukawa potential expressed by the equation of state of Duh and Mier-Y-Teran based on mean spherical approximation. The total average relative deviation of the correlation of the osmotic pressure data is 1.68%.

  1. Evaluating the fitness of human lysozyme transgenic dairy goats: growth and reproductive traits.

    Science.gov (United States)

    Jackson, Kathryn A; Berg, Jolene M; Murray, James D; Maga, Elizabeth A

    2010-12-01

    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 mammary gland to evaluate the reproductive fitness and growth and development of these animals compared to their non-transgenic counterparts and the impact of consuming a transgenic food product, lysozyme-containing milk. In males, none of the parameters of semen quality, including semen volume and concentration, total sperm per ejaculate, sperm morphology, viability and motility, were significantly different between transgenic bucks and non-transgenic full-sib controls. Likewise, transgenic females of this line did not significantly differ in the reproductive traits of gestation length and litter size compared to their non-transgenic counterparts. To evaluate growth, transgenic and non-transgenic kid goats received colostrum and milk from either transgenic or non-transgenic does from birth until weaning. Neither the presence of the transgene nor the consumption of milk from transgenic animals significantly affected birth weight, weaning weight, overall gain and post-wean gain. These results indicate that the analyzed reproductive and growth traits were not regularly or substantially impacted by the presence or expression of the transgene. The evaluation of these general parameters is an important aspect of defining the safety of applying transgenic technology to animal agriculture.

  2. THz time scale structural rearrangements and binding modes in lysozyme-ligand interactions.

    Science.gov (United States)

    Woods, K N

    2014-03-01

    Predicting the conformational changes in proteins that are relevant for substrate binding is an ongoing challenge in the aim of elucidating the functional states of proteins. The motions that are induced by protein-ligand interactions are governed by the protein global modes. Our measurements indicate that the detected changes in the global backbone motion of the enzyme upon binding reflect a shift from the large-scale collective dominant mode in the unbound state towards a functional twisting deformation that assists in closing the binding cleft. Correlated motion in lysozyme has been implicated in enzyme function in previous studies, but detailed characterization of the internal fluctuations that enable the protein to explore the ensemble of conformations that ultimately foster large-scale conformational change is yet unknown. For this reason, we use THz spectroscopy to investigate the picosecond time scale binding modes and collective structural rearrangements that take place in hen egg white lysozyme (HEWL) when bound by the inhibitor (NAG)3. These protein thermal motions correspond to fluctuations that have a role in both selecting and sampling from the available protein intrinsic conformations that communicate function. Hence, investigation of these fast, collective modes may provide knowledge about the mechanism leading to the preferred binding process in HEWL-(NAG)3. Specifically, in this work we find that the picosecond time scale hydrogen-bonding rearrangements taking place in the protein hydration shell with binding modify the packing density within the hydrophobic core on a local level. These localized, intramolecular contact variations within the protein core appear to facilitate the large cooperative movements within the interfacial region separating the α- and β- domain that mediate binding. The THz time-scale fluctuations identified in the protein-ligand system may also reveal a molecular mechanism for substrate recognition.

  3. A predictive model that describes the effect of prolonged heating at 70 to 90 degrees C and subsequent incubation at refrigeration temperatures on growth from spores and toxigenesis by nonproteolytic Clostridium botulinum in the presence of lysozyme.

    Science.gov (United States)

    Fernández, P S; Peck, M W

    1999-08-01

    Refrigerated processed foods of extended durability such as cook-chill and sous-vide foods rely on a minimal heat treatment at 70 to 95 degrees C and then storage at a refrigeration temperature for safety and preservation. These foods are not sterile and are intended to have an extended shelf life, often up to 42 days. The principal microbiological hazard in foods of this type is growth of and toxin production by nonproteolytic Clostridium botulinum. Lysozyme has been shown to increase the measured heat resistance of nonproteolytic C. botulinum spores. However, the heat treatment guidelines for prevention of risk of botulism in these products have not taken into consideration the effect of lysozyme, which can be present in many foods. In order to assess the botulism hazard, the effect of heat treatments at 70, 75, 80, 85, and 90 degrees C combined with refrigerated storage for up to 90 days on growth from 10(6) spores of nonproteolytic C. botulinum (types B, E, and F) in an anaerobic meat medium containing 2,400 U of lysozyme per ml (50 microg per ml) was studied. Provided that the storage temperature was no higher than 8 degrees C, the following heat treatments each prevented growth and toxin production during 90 days; 70 degrees C for >/=2,545 min, 75 degrees C for >/=463 min, 80 degrees C for >/=230 min, 85 degrees C for >/=84 min, and 90 degrees C for >/=33.5 min. A factorial experimental design allowed development of a predictive model that described the incubation time required before the first sample showed growth, as a function of heating temperature (70 to 90 degrees C), period of heat treatment (up to 2,545 min), and incubation temperature (5 to 25 degrees C). Predictions from the model provided a valid description of the data used to generate the model and agreed with observations made previously.

  4. Sounding natural: improving oral presentation skills

    OpenAIRE

    Grazia Busà, María

    2011-01-01

    This paper discusses how multimodal resources can be used to teach oral communication strategies, as exemplified in a course taught at the University of Padua, Italy. The course focused on lexicon and language structures in use, pronunciation and intonation, body language and cultural awareness. A variety of multimedia resources were used, including: pictures and illustrations; digital slides; audio files for pronunciation exercises and for audio-video feedback with the speech analysis softwa...

  5. Structural characteristics and plant-beneficial effects of bacteria colonizing the shoots of field grown conventional and genetically modified T4-lysozyme producing potatoes

    NARCIS (Netherlands)

    Rasche, F.; Marco-Noales, E.; Velvis, H.; Overbeek, van L.S.; Lopez, M.M.; Elsas, van J.D.; Sessitsch, A.

    2006-01-01

    Genetically modified potatoes expressing antibacterial protein T4 lysozyme may offer effective control strategies for bacterial pathogens causing severe potato diseases. Apart from this beneficial effect, it is very important to investigate such engineered potatoes carefully for potential adverse ef

  6. Structural characteristics and plant-beneficial effects of bacteria colonizing the shoots of field grown conventional and genetically modified T4-lysozyme producing potatoes

    NARCIS (Netherlands)

    Rasche, Frank; Marco-Noales, Ester; Velvis, Henk; van Overbeek, Leo S.; Lopez, Maria M.; van Elsas, Jan D.; Sessitsch, Angela

    2006-01-01

    Genetically modified potatoes expressing antibacterial protein T4 lysozyme may offer effective control strategies for bacterial pathogens causing severe potato diseases. Apart from this beneficial effect, it is very important to investigate such engineered potatoes carefully for potential adverse ef

  7. 信息动态%Investigation for Relationship Between Heat Treatment Process and Immunogenicity of Lysozyme in Egg By Spectroscopic Method

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    Thermal denaturation for lysozyme protein of egg has been investigated by using circular dichroism spectra and fluorescence spectra systematically. The corresponding immunogenicity of lysozyme protein has been tested with ELISA experiments. In addition, bioinformatics methods have also been used to investigate the spectral characteristics, corresponding immunogenicity change and conformational changes of the protein during thermal denaturation. Results from this study should be useful to the establishment of a spectral method examining the extent of thermal denaturation of the protein.

  8. Effects of dimerized lysozyme (KLP-602) on the cellular and humoral defence mechanisms in sheatfish (Silurus glanis): in vitro and in vivo study.

    Science.gov (United States)

    Morand, M; Siwicki, A; Pozet, F; Klein, P; Vinaize, J C; Keck, N

    1999-01-01

    This study examined the effects of the dimerized lysozyme (KLP-602) on the immunocompetence cell activity in sheatfish (Silurus glanis) and its influence in vivo on the non-specific defence mechanisms and protection against motile aeromonad septicaemia (MAS). The in vitro study showed that the lysozyme dimer (KLP-602), at concentrations between 5 and 50 micrograms/mL of medium significantly (P < 0.05) increased the respiratory burst activity and potential killing activity of pronephric macrophages, as well as the proliferative ability of pronephric lymphocytes stimulated by ConA and LPS. The in vivo study showed that injecting lysozyme dimer (Lydium-KLP) intraperitoneally at doses of 50 micrograms/kg bw stimulated cell-mediated and humoral-mediated imunity. On day 5, after application of Lydium-KLP in vivo, a statistically higher (P < 0.05) respiratory burst activity and potential killing activity of blood and pronephros phagocytes were observed. A higher proliferative ability of blood and pronephros lymphocytes stimulated by Concanavaline A (ConA) or lipopolysaccharide (LPS) was also observed. At the same time, the myeloperoxidase activity in the PMN cells and the lysozyme activity and total Ig levels in serum were significantly higher (P < 0.05), compared to the control group. A challenge test with Aeromonas hydrophila showed that dimerized lysozyme increased the protection against MAS. Dimerized lysozyme stimulates non-specific cellular and humoral mechanisms and protection against MAS in sheatfish.

  9. Time-dependent X-ray diffraction studies on urea/hen egg white lysozyme complexes reveal structural changes that indicate onset of denaturation

    Science.gov (United States)

    Raskar, Tushar; Khavnekar, Sagar; Hosur, Madhusoodan

    2016-01-01

    Temporal binding of urea to lysozyme was examined using X-ray diffraction of single crystals of urea/lysozyme complexes prepared by soaking native lysozyme crystals in solutions containing 9 M urea. Four different soak times of 2, 4, 7 and 10 hours were used. The five crystal structures (including the native lysozyme), refined to 1.6 Å resolution, reveal that as the soaking time increased, more and more first-shell water molecules are replaced by urea. The number of hydrogen bonds between urea and the protein is similar to that between protein and water molecules replaced by urea. However, the number of van der Waals contacts to protein from urea is almost double that between the protein and the replaced water. The hydrogen bonding and van der Waals interactions are initially greater with the backbone and later with side chains of charged residues. Urea altered the water-water hydrogen bond network both by replacing water solvating hydrophobic residues and by shortening the first-shell intra-water hydrogen bonds by 0.2 Å. These interaction data suggest that urea uses both ‘direct’ and ‘indirect’ mechanisms to unfold lysozyme. Specific structural changes constitute the first steps in lysozyme unfolding by urea. PMID:27573790

  10. Effects of reduced levels of sulfite in wine production using mixtures with lysozyme and dimethyl dicarbonate on levels of volatile and biogenic amines.

    Science.gov (United States)

    Ancín-Azpilicueta, Carmen; Jiménez-Moreno, Nerea; Moler, José Antonio; Nieto-Rojo, Rodrigo; Urmeneta, Henar

    2016-10-01

    Sulphur dioxide (SO2) is an important preservative for wine, but its presence in foods can cause allergies and this has given impetus to the research for alternatives. The aim of this study was to reduce levels of sulfite in wine production using mixtures with lysozyme and dimethyl dicarbonate and examine the influence on levels of volatile and biogenic amines. To do so, vinifications were carried out using lysozyme, dimethyl dicarbonate (DMDC) and mixtures of these with SO2 in different concentrations (25 and 50 mg l(-1)). Results were compared with a control vinification with only SO2 (50 mg l(-1)). Mixing low concentrations of SO2 with lysozyme and DMDC reduced the concentration of biogenic amines (histamine, tyramine, putrescine, cadaverine, phenylethylamine + spermidine and spermine). In general, the total concentration of volatile amines (dimethylamine, isopropylamine, isobutylamine, pyrrolidine, ethylamine, diethylamine, amylamine and hexylamine) was higher in the sample fermented only with SO2. The concentrations of amines with secondary amino groups (dimethylamine, diethylamine, pyrrolidine) were higher in the sample only fermented with SO2 than those fermented with DMDC and lysozyme or with a mixture of preservatives. When SO2 was the only preservative in wine, total amine concentration (biogenic and volatile amines) was higher than for the rest of the treatments. Lysozyme by itself, and lysozyme mixed with SO2, both reduced the formation of biogenic amines but given the antioxidant activity of SO2 the use of the preservative mixture seems more advisable.

  11. Crystallization and evaluation of hen egg-white lysozyme crystals for protein pH titration in the crystalline state.

    Science.gov (United States)

    Iwai, Wakari; Yagi, Daichi; Ishikawa, Takuya; Ohnishi, Yuki; Tanaka, Ichiro; Niimura, Nobuo

    2008-05-01

    To observe the ionized status of the amino acid residues in proteins at different pH (protein pH titration in the crystalline state) by neutron diffraction, hen egg-white lysozyme was crystallized over a wide pH range (2.5-8.0). Crystallization phase diagrams at pH 2.5, 6.0 and 7.5 were determined. At pH diagram, and at pH > 4.5 the border shifted to the right (higher precipitant concentration). The qualities of these crystals were characterized using the Wilson plot method. The qualities of all crystals at different pH were more or less equivalent (B-factor values within 25-40). It is expected that neutron diffraction analysis of these crystals of different pH provides equivalent data in quality for discussions of protein pH titration in the crystalline state of hen egg-white lysozyme.

  12. 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....

  13. Molecular cloning and characterization of c-type lysozyme gene in orange-spotted grouper, Epinephelus coioides.

    Science.gov (United States)

    Wei, Shina; Huang, Youhua; Cai, Jia; Huang, Xiaohong; Fu, Jing; Qin, Qiwei

    2012-08-01

    Lysozymes are key proteins of the host innate immune system against pathogen infection. In this study, a c-type lysozyme gene (Ec-lysC) was cloned and characterized from orange-spotted grouper, Epinephelus coioides. The full-length Ec-lysC cDNA is composed of 533 bp and encodes a polypeptide of 144-residue protein with 94% identity to lysC of Kelp grouper, Epinephelus bruneus. The genomic DNA of Ec-lysC consists of 4 exons and 3 introns, with a total length of 1897 bp. Amino acid sequence alignment showed that Ec-lysC possessed conserved catalytic residues (Glu50 and Asp67) and "GSTDYGIFQINS" motif. RT-PCR results showed that Ec-lysC transcript was most abundant in head kidney and less in muscle. The expression of Ec-lysC was differentially up-regulated in head kidney after stimulation with lipopolysaccharide (LPS), Vibrio alginolyticus and Singapore grouper iridovirus (SGIV). Subcellular localization analysis revealed that Ec-lysC was distributed predominantly in the cytoplasm. The recombinant Ec-lysC (rEc-lysC) had lytic activities against Gram-positive bacteria Micrococcus lysodeikticus, Staphylococcus aureus, Streptococcus iniae and Gram-negative bacteria V. alginolyticus. The lysozyme acted on M. lysodeikticus cell walls as shown by scanning electron microscopy (SEM). Furthermore, overexpression of Ec-lysC in grouper cells delayed the occurrence of CPE induced by SGIV and inhibited the viral gene transcription significantly. Taken together, Ec-lysC might play an important role in grouper innate immune responses to invasion of bacterial and viral pathogens. C-type lysozyme gene from E. coioides (Ec-lysC) was identified and characterized.

  14. Amyloid fibril formation and seeding by wild-type human lysozyme and its disease-related mutational variants.

    Science.gov (United States)

    Morozova-Roche, L A; Zurdo, J; Spencer, A; Noppe, W; Receveur, V; Archer, D B; Joniau, M; Dobson, C M

    2000-06-01

    Wild-type human lysozyme and its two stable amyloidogenic variants have been found to form partially folded states at low pH. These states are characterized by extensive disruption of tertiary interactions and partial loss of secondary structure. Incubation of the proteins at pH 2.0 and 37 degrees C (Ile56Thr and Asp67His variants) or 57 degrees C (wild-type) results in the formation of large numbers of fibrils over several days of incubation. Smaller numbers of fibrils could be observed under other conditions, including neutral pH. These fibrils were analyzed by electron microscopy, Congo red birefringence, thioflavine-T binding, and X-ray fiber diffraction, which unequivocally show their amyloid character. These data demonstrate that amyloidogenicity is an intrinsic property of human lysozyme and does not require the presence of specific mutations in its primary structure. The amyloid fibril formation is greatly facilitated, however, by the introduction of "seeds" of preformed fibrils to the solutions of the variant proteins, suggesting that seeding effects could be important in the development of systemic amyloidosis. Fibril formation by wild-type human lysozyme is greatly accelerated by fibrils of the variant proteins and vice versa, showing that seeding is not specific to a given protein. The fact that wild-type lysozyme has not been found in ex vivo deposits from patients suffering from this disease is likely to be related to the much lower population of incompletely folded states for the wild-type protein compared to its amyloidogenic variants under physiological conditions. These results support the concept that the ability to form amyloid is a generic property of proteins, but one that is mitigated against in a normally functioning organism. Copyright 2000 Academic Press.

  15. Effect of lysozyme chloride on betel quid chewing aggravated gastric oxidative stress and hemorrhagic ulcer in diabetic rats

    Institute of Scientific and Technical Information of China (English)

    Chen-Road Hung

    2005-01-01

    AIM: To evaluate the protective effect of lysozyme chloride on betel quid chewing (BQC) aggravated gastric oxidative stress and hemorrhagic ulcer in rats with diabetes mellitus (DM).METHODS: Male Wistar rats were challenged intravenously with streptozotocin (65 mg/kg) to induce DM. Rats were fed with regular pellet food or BQC-containing diets. After 90 d, rats were deprived of food for 24 h. Rat stomachs were irrigated for 3 h with normal saline or simulated gastric juice. Rats were killed and gastric specimens were harvested.RESULTS: An enhancement of various gastric ulcerogenic parameters, including acid back-diffusion, mucosal lipid peroxide generation, as well as decreased glutathione levels and mucus content, were observed in DM rats. After feeding DM rats with BQC, an exacerbation of these ulcerogenic parameters was achieved. Gastric juice caused a further aggravation of these ulcerogenic parameters. Daily intragastric lysozyme chloride dose-dependently inhibited exacerbation of various ulcerogenic parameters in those BQC-fed DM rats.CONCLUSION: (1) Gastric juice could aggravate both DM and BQC-fed DM rat hemorrhagic ulcer; (2) BQC exacerbated gastric hemorrhagic ulcer in DM rats via enhancing oxidative stress and reducing defensive factors; (3) lysozyme chloride effectively protected BQC aggravated gastric damage in DM rats.

  16. Production of biofunctionalized MoS2 flakes with rationally modified lysozyme: a biocompatible 2D hybrid material

    Science.gov (United States)

    Siepi, Marialuisa; Morales-Narváez, Eden; Domingo, Neus; Monti, Daria Maria; Notomista, Eugenio; Merkoçi, Arben

    2017-09-01

    Bioapplications of 2D materials embrace demanding features in terms of environmental impact, toxicity and biocompatibility. Here we report on the use of a rationally modified lysozyme to assist the exfoliation of MoS2 bulk crystals suspended in water through ultrasonic exfoliation. The design of the proposed lysozyme derivative provides this exfoliated 2D-materail with both, hydrophobic groups that interact with the surface of MoS2 and hydrophilic groups exposed to the aqueous medium, which hinders its re-aggregation. This approach, clarified also by molecular docking studies, leads to a stable material (ζ-potential, 27  ±  1 mV) with a yield of up to 430 µg ml-1. The bio-hybrid material was characterized in terms of number of layers and optical properties according to different slots separated by diverse centrifugal forces. Furthermore the obtained material was proved to be biocompatible using human normal keratinocytes and human cancer epithelial cells, whereas the method was demonstrated to be applicable to produce other 2D materials such as graphene. This approach is appealing for the advantageous production of high quality MoS2 flakes and their application in biomedicine and biosensing. Moreover, this method can be applied to different starting materials, making the denatured lysozyme a promising bio-tool for surface functionalization of 2D materials.

  17. Impact of Microscale and Pilot-Scale Freeze-Drying on Protein Secondary Structures: Sucrose Formulations of Lysozyme and Catalase.

    Science.gov (United States)

    Peters, Björn-Hendrik; Leskinen, Jari T T; Molnár, Ferdinand; Ketolainen, Jarkko

    2015-11-01

    Microscale (MS) freeze-drying offers rapid process cycles for early-stage formulation development. The effects of the MS approach on the secondary structures of two model proteins, lysozyme and catalase, were compared with pilot-scale (PS) vial freeze-drying. The secondary structures were assessed by attenuated total reflection Fourier transformed infrared spectroscopy. Formulations were made with increasing sucrose-protein ratios. Freeze-drying protocols involved regular cooling without thermal treatment and annealing with MS and PS equipment, and cooling rate variations with the MS. Principal component analysis of smoothed second-derivative amide I spectra revealed sucrose-protein ratio-dependent shifts toward α-helical structures. Transferability of sucrose-protein formulations from MS to PS vial freeze-drying was evidenced at regular cooling rates. Local differences in protein secondary structures between the bottom and top of sucrose-catalase samples could be detected at the sucrose-catalase ratios of 1 and 2, this being related to the initial filling height and ice crystal morphology. Annealing revealed temperature, protein, formulation, and sample location-dependent effects influencing surface morphology at the top, or causing protein secondary structure perturbation at the bottom. With the MS approach, protein secondary structure differences at different cooling rates could be detected for sucrose-lysozyme samples at the sucrose-lysozyme ratio of 1.

  18. Mouse SLLP1, a sperm lysozyme-like protein involved in sperm-egg binding and fertilization.

    Science.gov (United States)

    Herrero, María Belén; Mandal, Arabinda; Digilio, Laura C; Coonrod, Scott A; Maier, Bernhard; Herr, John C

    2005-08-01

    This study demonstrates the retention of mouse sperm lysozyme-like protein (mSLLP1) in the equatorial segment of spermatozoa following the acrosome reaction and a role for mSLLP1 in sperm-egg binding and fertilization. Treatment of cumulus intact oocytes with either recmSLLP1 or its antiserum resulted in a significant (P sperm-oolemma binding. A complete inhibition of binding and fusion of spermatozoa to the oocyte occurred at 12.5 muM concentration of recmSLLP1, while conventional chicken and human lysozymes did not block sperm-egg binding. mSLLP1 showed receptor sites in the perivitelline space as well as on the microvillar region of the egg plasma membrane. The retention of mSLLP1 in the equatorial segment of acrosome-reacted sperm, the inhibitory effects of both recmSLLP1 and antibodies to SLLP1 on in vitro fertilization with both cumulus intact and zona-free eggs, and the definition of complementary SLLP1-binding sites on the egg plasma membrane together support the hypothesis that a c lysozyme-like protein is involved in the binding of spermatozoa to the egg plasma membrane during fertilization.

  19. Effect of ethanol-water mixture on the structure and dynamics of lysozyme: A fluorescence correlation spectroscopy study

    Science.gov (United States)

    Chattoraj, Shyamtanu; Mandal, Amit Kumar; Bhattacharyya, Kankan

    2014-03-01

    Effect of ethanol-water mixture on the hydrodynamic radius (rH) and conformational dynamics of lysozyme has been studied by circular dichroism, emission spectra, and fluorescence correlation spectroscopy. For this purpose, the protein lysozyme is covalently labeled near the active site with a fluorescent probe, alexa 488. The ethanol molecules are sequestered near the hydrophobic tryptophan residues as indicated by the blue shift of the emission maximum of tryptophan. It is observed that both size (rH) and time constant of conformational relaxation (τR) of lysozyme oscillate with increase in ethanol concentration. The rH of the protein fluctuates from 19 Å in the native state, to a minimum of 13 Å, and a maximum of 29 Å. It is proposed that the oscillating behavior arises from competition between mutual interaction among protein, ethanol, and water. The fluorescence intensity fluctuates because of quenching of the fluorescence of the probe (alexa) by the free amino group of certain residues (e.g., tryptophan). Rate of inter-conversion (folding dynamics) between the open (fluorescent) and closed (non-fluorescent) form has been determined and is found to exhibit similar oscillation with variation in ethanol content.

  20. Fluorescence detection of lipid-induced oligomeric intermediates involved in lysozyme "amyloid-like" fiber formation driven by anionic membranes.

    Science.gov (United States)

    Melo, Ana M; Ricardo, Joana C; Fedorov, Aleksander; Prieto, Manuel; Coutinho, Ana

    2013-03-14

    Recent findings implicate that "amyloid-like" fiber formation by several non-amyloidogenic proteins/peptides can be triggered by negatively charged lipid membranes. In order to elucidate the factors that govern the formation of these structures, the interaction of lysozyme with phosphatidylserine-containing lipid vesicles was studied by steady-state and time-resolved fluorescence measurements. Three consecutive stages in the interaction of Alexa488-fluorescently labeled lysozyme (Lz-A488) with acidic lipid vesicles were identified in ensemble average measurements. The variation of the mean fluorescence lifetime of Lz-A488 as a function of the surface coverage of the liposomes was quantitatively described by a cooperative partition model that assumes that monomeric lysozyme molecules partition into the bilayer surface and reversibly assemble into oligomers with k subunits (k ≥ 6). The global fit to the experimental data covering a wide range of experimental conditions was performed by taking into account electrostatic effects by means of the Gouy-Chapman theory using a single self-consistent pair of parameters (aggregation constant and stoichiometry). The lipid-protein supramolecular assemblies formed at a low lipid/protein molar ratio were further characterized by fluorescence lifetime imaging microscopy at the single-fiber level, which reported that quenched oligomers are the predominant species in these structures.