Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:3.2.1.17 (lysozyme)
21,489 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Several humoral immune factors were studied in a group of cultured halibut (Hippoglossus hippoglossus L.). The serum protein and IgM concentration was comparable to levels seen in other teleost species. A strong antibody activity against TNP-BSA was observed but not against other antigens tested. Lysozyme and anti-protease activity was detected and showed variable heat sensitivity. Unlike the anti-protease activity, the lysozyme activity of the sera was not sensitive to storage at -20 degrees C. No spontaneous haemolytic activity was observed and the sera had no bactericidal effect on any of the bacterial strains tested. Iron binding capacity of the sera was high. Individual variation was considerable in all the factors tested.
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PMID:Humoral immune parameters of cultured Atlantic halibut (Hippoglossus hippoglossus L.). 1155 81

The changes in some factors of the innate immunity (phagocytosis, complement, lysozyme); haematological parameters-leukocytes, erythrocytes, differential white blood cell counts, haemoglobin, haematocrit and the serum concentrations of the microelements zinc and iron in six 2- to 3-months-old female piglets after the intravenous administration of lipopolysaccharide from Escherichia coli 0111:B4 were determined. It was found out that 1 h after the administration of lipopolysaccharide at the dosage rate of 10 microg/kg body weight resulted in a decrease in the phagocytic parameters, i.e. the phagocytic number and the index of phagocytic activity, which was followed by an increase in their values between post treatment hours 2 and 4. The leukocyte counts had decreased by hour 2 after the injection, but thereafter increased, and at post treatment hour 72, a leukocytosis was observed. The differential white blood cell counts were characterized by a shift to the left between hours 2 and 4 and a statistically significant increase in lymphocyte counts at hour 48 of the experiment. The serum zinc concentrations were increased an hour after the lipopolysaccharide application; after which their average values were lower. The haemolytic activities (CH50) of the classical and the alternative pathways of complement activation decreased. The haemolytic activity (CH50) for the classical pathway began to increase at hour 48 following the treatment. Significant changes were not observed in lysozyme activity, serum iron concentrations or the related haematological parameters (erythrocytes and haemoglobin).
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PMID:Changes in some factors of the innate immunity and serum zinc and iron concentrations in pigs following intravenous administration of Escherichia coli lipopolysaccharide. 1158 98

The effect of temperature (8, 12, 15 and 18 degrees C) on a variety of non-specific defence and haematological parameters was examined in three geographically distinct reared strains (Canadian, Icelandic, Norwegian) of Atlantic halibut. The results indicate that temperature exerts a considerable influence on some blood parameters (packed cell volume and the percentage population of leucocytes in peripheral blood) and on some humoral parameters (serum lysozyme activity and serum protein levels) of halibut. A high temperature of 18 degrees C caused a decrease in the number of circulating blood cells and an increase in serum lysozyme levels; effects consistent with those reported within the literature for stress. The different strains of halibut exhibited differing responses with respect to differential counts of peripheral blood lymphocytes and thrombocytes, and to serum protein concentrations, serum lysozyme activity, serum iron content, unsaturated iron binding capacity of serum and O2- production by kidney macrophages.
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PMID:The effect of temperature on non-specific defence parameters of three strains of juvenile Atlantic halibut (Hippoglossus hippoglossus L.). 1186 31

The Escherichia coli TonB protein serves to couple the cytoplasmic membrane proton motive force to active transport of iron-siderophore complexes and vitamin B(12) across the outer membrane. Consistent with this role, TonB has been demonstrated to participate in strong interactions with both the cytoplasmic and outer membranes. The cytoplasmic membrane determinants for that interaction have been previously characterized in some detail. Here we begin to examine the nature of TonB interactions with the outer membrane. Although the presence of the siderophore enterochelin (also known as enterobactin) greatly enhanced detectable cross-linking between TonB and the outer membrane receptor, FepA, the absence of enterochelin did not prevent the localization of TonB to the outer membrane. Furthermore, the absence of FepA or indeed of all the iron-responsive outer membrane receptors did not alter this association of TonB with the outer membrane. This suggested that TonB interactions with the outer membrane were not limited to the TonB-dependent outer membrane receptors. Hydrolysis of the murein layer with lysozyme did not alter the distribution of TonB, suggesting that peptidoglycan was not responsible for the outer membrane association of TonB. Conversely, the interaction of TonB with the outer membrane was disrupted by the addition of 4 M NaCl, suggesting that these interactions were proteinaceous. Subsequently, two additional contacts of TonB with the outer membrane proteins Lpp and, putatively, OmpA were identified by in vivo cross-linking. These contacts corresponded to the 43-kDa and part of the 77-kDa TonB-specific complexes described previously. Surprisingly, mutations in these proteins individually did not appear to affect TonB phenotypes. These results suggest that there may be multiple redundant sites where TonB can interact with the outer membrane prior to transducing energy to the outer membrane receptors.
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PMID:TonB interacts with nonreceptor proteins in the outer membrane of Escherichia coli. 1187 15

Electrophilic complexes of iron and chromium which have been reported to react with proteins in solution have been reacted with hen-egg white lysozyme (HEWL) in both the solution and crystal phases under similar pH and buffer conditions. This work was carried out with a view to developing novel side-chain selective heavy metal derivatives for protein X-ray crystallographic studies. Reaction of HEWL with a tricarbonyldienyliron cation (1) in aqueous solution led to modification of the sole histidine residue with concurrent reversible modification of other protein residues. Reaction of (1) with crystalline HEWL showed no covalent binding and only a build up of a hydrolysis product in the water channels of the crystal was observed. Reactions with a series of tricarbonylarylchromium pyrylium salts (2) led to the formation of stable covalent HEWL derivatives in solution. Chromatographic and IR spectroscopic studies showed that binding took place specifically at the epsilon-amino group of lysine residues to give a series of mono- and di-substituted products. When crystals of HEWL were soaked with the chromium reagents covalent binding to some of the lysine residues was also observed. In contrast, HEWL crystals which had their lysine side chains disabled did not bind any of the chromium reagents.
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PMID:FT-IR observation of covalent labelling of lysozyme crystals by organometallic complexes of transition metals. 1194

The iron-binding glycoprotein human lactoferrin (hLF) is involved in the host defense against infection and is a modulator of inflammatory reactions. We generated monoclonal antibodies (mAbs) to hLF as tools to assist both structure-function studies and the development of recombinant human lactoferrin for applications in human health care. Binding experiments with ten distinct anti-hLF mAbs to tryptic and recombinant hLF fragments in ELISA and/or on immunoblots revealed that five mAbs bound to conformational epitopes residing in the N-lobe (residues 1 to 334), whereas the other five bound to C-lobe conformational epitopes (residues 335 to 692). None of the mAbs bound to hLF denatured upon reduction. Monoclonal antibody E11 appeared to bind to the arginine-rich N-terminus of hLF, which is the binding site for heparin, bacterial lipopolysaccharide, human lysozyme, DNA and receptors. The dissociation constant of the distinct mAbs for hLF ranged from 0.5 to 18 nM, without differences in affinity for unsaturated or iron-saturated hLF, indicating that the conformational changes subject to incorporation of iron do not seem to affect the exposure and/or conformation of the antibody epitopes. The mAbs did not bind to human transferrin, a protein closely related to hLF in size, primary amino acid sequence and structure. Two C-lobe specific mAbs, E2 and E8, cross-reacted with bovine and/or porcine lactoferrin, indicating that human, bovine and porcine lactoferrin share antigenic determinants. This panel of mAbs will be used to develop quantitative and qualitative immunoassays for hLF and to delineate which regions of hLF are relevant to its anti-infective and anti-inflammatory properties.
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PMID:Characterization of monoclonal antibodies against human lactoferrin. 1216 35

Iron-porphyrin proteins (catalase, peroxidase, hemoglobin, cytochrome C) represent an important group of redoxenzymes which have vitally important functions in micro-organisms. A biochemiluminescent method was employed for the detection of iron-porphyrin proteins. The reaction of luminol oxidation with H2O2 is accompanied by chemiluminescence. The rate of hydrogen peroxide decomposition increased 10(5)-10(7) -fold in the presence of the above enzymes as compared with ferrous (or ferric) ions. Possible application of this reaction for the detection of iron-porphyrin proteins of microbial origin was studied. Other authors have suggested this reaction for the detection of extraterrestrial life. Kinetics of the above reaction in the presence of iron-porphyrin proteins were shown to differ both in amplitude and duration of the signal from the pattern observed in the presence of non-hemin catalysts. The reaction pattern in the presence of mixed-soil populations is similar to those observed with pure bacterial cultures and individual iron-porphyrin proteins. Photometric tests revealed that among preparations studied the addition of 0.01% lysozyme was the most effective in destroying cell walls in microbial populations. However, removal of cell walls is not a necessary prerequisite for the detection of iron porphyrin since, for effective luminol oxidation with H2O2 the medium should be kept at pH 12.0. Pretreatment of microbial suspensions with ultrasound increased 2-fold the total signal due to iron porphyrins. The above method gives a reproducible signal indicating the presence of iron porphyrins when sterile nutrient media were innoculated with desert soil samples (Repeteck, Kara-Kum) and incubated for 13 hr. The device was able to detect the presence of no less than 10(5) - 10(6) cells per ml. The addition of limonite (Fe2O3 X nH2O) does not result in the appearance of an appreciable signal in the luminol + H2O2 system.
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PMID:Detection of iron-porphyrin proteins with a biochemiluminescent method in search of extraterrestrial life. 1266 23

A decisive event in the evolution of mammals from synapsid reptiles was the modification of ventral thoracic-abdominal epidermal glands to form the mammary gland. The natural selection events that drove the process may have been the provision of certain immunological agents in dermal secretions of those nascent mammals. This is mirrored by similar innate immune factors in mammalian sebum and in protherian and eutherian milks. On the basis of studies of existing mammalian orders, it is evident that immune agents in milk such as immunoglobulins, iron-binding proteins, lysozyme, oligosaccharides, and leukocytes compensate for developmental delays in early postnatal production of antimicrobial factors. At least in human milk, anti-inflammatory and immunomodulating agents also evolved to provide different types of protection for the offspring. In addition, investigations reveal that the types or concentrations of immunological agents in milk vary depending upon the type of placenta, lactation pattern, and environment of the species.
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PMID:Evolution of the mammary gland defense system and the ontogeny of the immune system. 1275 92

According to the method of Ohmori et al. (J. Colloid Interface Sci. 150 (1992) 594), a procedure is examined for the buildup of uniform silica layers on monodispersed hematite particles. It appears that the silica layer resulting is homogeneous and the layer thickness is controlled by the concentration of tetraethylorthosilicate (TEOS) in the medium. Further, egg PC liposomes, a typical biocolloid, are introduced onto the silica-coated hematite particle. The formation was proceeded by two types of processes: (1) heterocoagulation between the silica-coated hematite and egg PC liposomes by controlling the concentration of LaCl(3) in the medium, or (2) buildup using two proteins (lysozyme or cytochrome C) as binder molecules. These results were analyzed by zeta-potential measurements and a contact-type X-ray microscope, which is a unique technique for obtaining X-ray images of biological specimens in water with high resolution.
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PMID:Characterization of silica-coated hematite and application to the formation of composite particles including egg yolk PC liposomes. 1288 24

The aim of this study was to explore the antimicrobial activity of human follicular fluid (HFF), to test the hypothesis that different strains of the same bacterial species could display different patterns of susceptibility to antimicrobial action of HFF, and to preliminarily investigate the possible mechanism of antimicrobial action of this fluid. Antimicrobial activity of 60 samples of HFF toward 30 Streptococcus agalactiae strains was determined by the agar diffusion method and broth dilution method. To explore the mechanism of antimicrobial activity, biochemical analyses were performed with selected fluid samples. The obtained results indicate that 38.3% fluid samples did not inhibit bacterial growth, 53.3% showed moderate and 8.3% high antimicrobial activity. The tested effect of HFF on S. agalactiae strains was bactericidal and was not strain dependent. Lysozyme activity was detected in HFF exhibiting antimicrobial activity. There were no statistically significant differences in concentrations of estradiol, progesterone, transferrin, iron, total protein and albumin levels among tested samples regardless of the different rate of antimicrobial activity. The obtained results indicate that lysozyme is most probably a crucial antibacterial agent in this fluid; however, some other still unidentified factors may contribute to it.
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PMID:Antimicrobial activity of human follicular fluids. 1455 60


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