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)

The cDNA sequence of a salivary lysozyme in Helicoverpa zea (Lepidoptera: Noctuidae) was determined. The full-length cDNA is 1,032 bp, and it encodes a protein of 142 amino acids. This lysozyme has 90% identity with Heliothis virescens lysozyme and 76% identity with Manduca sexta lysozyme. There is a signal peptide of 20 amino acids at the N-terminus. The mature protein is about 14.4 kDa without the signal peptide. The pI value is greater than 9.5 as determined by isoelectric focusing. From genomic DNA, two introns and three exons were within the open reading frame (ORF). Southern blot analysis indicated that it is a single-copy gene. A time-course study revealed that the H. zea lysozyme gene was differentially expressed in the labial glands during the development of fifth-instar larvae, with the peak level of lysozyme mRNA being detected on day 1. Dot blot analysis showed different levels of H. zea lysozyme expression when the caterpillars fed on different plants. Further, the H. zea lysozyme could be detected with antibodies raised against the M. sexta lysozyme, and it was one of the most abundant secreted proteins in saliva collected directly from the caterpillar's spinneret. The potential role of the lysozyme on host plants in mediating susceptibility to bacterial disease is discussed in the context of tritrophic interactions.
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PMID:Characterization of a salivary lysozyme in larval Helicoverpa zea. 1572 65

Submucosal glands are abundant (approximately 1 gland/mm2) secretory structures in the tracheobronchial airways of the human lung. Because submucosal glands express antibacterial proteins, it has been proposed that they contribute to lung defense. However, this concept is challenged by the fact that mice do not have submucosal glands in their bronchial airways, yet are quite resistant to bacterial lung infection. The contribution of airway submucosal glands to host defense is also debated as a pathophysiologic component of cystic fibrosis lung disease. Here, we asked whether submucosal glands protect airways against bacterial infection. By comparing tracheal xenograft airways with and without glands, we found that the presence of glands enhanced bacterial killing in vivo and by airway secretions in vitro. Moreover, immunodepletion studies suggested that lysozyme is a major antibacterial component secreted by submucosal glands. These studies provide evidence that submucosal glands are a major source of antibacterials critical for maintaining sterile airways.
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PMID:Lysozyme secretion by submucosal glands protects the airway from bacterial infection. 1574 32

Lysozyme is a ubiquitous and abundant, cationic, antimicrobial polypeptide of leukocytes and epithelia, but its biological function in host defense is largely unexplored. To ascertain the role of lysozyme during bacterial infection of murine airways, we exposed the airways of lysozyme M-deficient (lys M-/-) mice to the pulmonary pathogen Pseudomonas aeruginosa and examined the host's response to infection. Despite partial compensation as a result of the appearance of lysozyme P in the infected airways of lys M-/- mice, these lys M-/- mice showed decreased clearance of P. aeruginosa compared with their lys M+/- or lys M+/+ littermates. Lysozyme contributes to optimal clearance of P. aeruginosa from the murine airways.
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PMID:Decreased clearance of Pseudomonas aeruginosa from airways of mice deficient in lysozyme M. 1620 48

The hemocytes of invertebrates play key roles in both cellular and humoral immune reactions by phagocytosis or delivering immune factors such as lectin and anti-microbial peptides. Bacterial infection causes changes in components such as lectins, anti-bacterial peptides, and lysosomal enzymes of plasma or hemolymph in molluscs. Previously, we found that infection with the protozoan parasite, Perkinsus, increases lectin synthesis in hemocytes. In order to investigate the patterns of genes expressed in Manila clams (Ruditapes philippinarum) infected with the protozoan parasite Perkinsus olseni, we constructed a cDNA library and sequenced 1850 clones (expressed sequence tags). A total of 79 ESTs, were related to 29 functional immune genes such as C-type lectin, lysozyme, and cystatin B, in Manila clams. Lectins were the largest group of immune-function ESTs found in our Manila clams library. Among 7 lectin clones, two full length cDNAs of lectins were cloned. MCL-3, which is a simple C-type lectin composed of 151 amino acids, has a relatively short signal sequence of 17aa and single carbohydrate-recognition domain (CRD) of approximately 130 residues. It is highly homologous to eel C-type lectin. The sequence of mc-sialic acid-binding lectin consists of 168 amino acid residues with molecular weight of 19.2 and shows high homology to sialic acid-binding lectin from the snail, Cepaea hortensis. The expression of 7 different lectins in hemocytes was analyzed by RT-PCR using gene-specific primers. Hemocytes from Perkinsus-infected clam expressed different sets of lectins than with Vibrio infection. These results demonstrate that several lectins are involved in Manila clam innate immunity and different challenges induce expression of different lectins.
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PMID:Analysis of EST and lectin expressions in hemocytes of Manila clams (Ruditapes philippinarum) (Bivalvia: Mollusca) infected with Perkinsus olseni. 1669 Jan 26

We established a transgenic zebrafish strain expressing chicken lysozyme gene under the control of the Japanese flounder keratin gene promoter, and investigated its resistance to a pathogenic bacterial infection. To generate the lysozyme transgenic construct, Japanese flounder keratin promoter was linked to both the hen egg white (HEW) lyoszyme gene and green fluorescence protein (GFP) gene used as a selection marker for the transgenic strains, in a recombinant plasmid. The recombinant plasmid was microinjected into fertilized zebrafish eggs. In F2 transgenic zebrafish, GFP expression was strong in the epithelial tissues, liver and gill from the embryonic stage to the adult stage. The expressions of HEW lysozyme and GFP mRNA were confirmed in the liver and skin by RT-PCR. Western blot analysis showed that both HEW lysozyme and GFP were present in protein extracts from the liver of transgenic zebrafish, but not in protein extracts from the muscle. The lytic activity of protein extracts from the liver (assessed by a lysoplate assay using Micrococcus lysodeikticus as a substrate) was 1.75 times higher in F2 transgenic zebrafish than in the wild type. In a challenge experiment, 65% of the F2 transgenic fish survived an infection of Flavobacterium columnare and 60% survived an infection of Edwardsiella tarda, whereas 100% of the control fish were killed by both pathogens. However, the survival rates of the transgenic fish were not significantly higher when higher concentrations of bacteria were used.
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PMID:Transgenic zebrafish expressing chicken lysozyme show resistance against bacterial diseases. 1677 53

Serum-mediated reduction in bacterial count and expression of a number of immune response genes in the blood of Atlantic cod, Gadus morhua were investigated following intraperitoneal vaccination with heat-killed Listonella (Vibrio) anguillarum. Blood was collected from the caudal vein of both vaccinated and non-vaccinated (PBS-injected) fish at 0, 1, 3, 7 and 10 days post-vaccination (dpv). Serum protein concentration and antibacterial activity of the serum samples were determined. Whole blood was used for semi-quantitative RT-PCR of immune-related genes. Total serum protein was not significantly different between the vaccinated and non-vaccinated groups. Sera from the vaccinated fish significantly reduced L. anguillarum count on 3 dpv, with reductions of at least 2 log colony forming units per ml (CFU/ml) relative to the non-vaccinated fish. Expression of antibacterial genes, bactericidal/permeability-increasing protein/lipopolysaccharide-binding protein (BPI/LBP), g-type lysozyme and transferrin was significantly upregulated in the vaccinated fish, with maximum expression within 7 dpv. Cytotoxic-related and cell-mediated immunity genes such as, apolipoprotein A-I and the non-specific cytotoxic cell receptor protein (NCCRP-1) had maximum expression at 3 and 7 dpv, respectively. Significant upregulation in expression of pro-inflammatory cytokines, IL-1 beta and IL-8 was also observed in the vaccinated fish at 1 dpv. The upregulation of immune response genes following vaccination provides valuable information in the understanding of immune mechanisms against vibriosis in Atlantic cod particularly on the acute phase response during bacterial infection.
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PMID:Intraperitoneal vaccination of Atlantic cod, Gadus morhua with heat-killed Listonella anguillarum enhances serum antibacterial activity and expression of immune response genes. 1822 48

Severe pneumonia is found in simultaneous influenza pneumonia and bacterial infection, and suggests a relationship with immunological mechanisms. Here, we performed two-dimensional gel electrophoresis to detect immunological molecules related to the fulminant pneumonia caused by influenza virus and Streptococcus pneumoniae co-infection in mice. We found two spots that were expressed strongly in co-infected mouse lungs, compared with S. pneumoniae or influenza virus singly infected mouse lungs. The spots were analysed by mass spectrometry, and identified as alpha-1 anti-trypsin (A1AT), known as an anti-protease for neutrophil-derived proteolytic enzymes, and creatine kinase, which reflects a greater degree of lung damage and cell death. A1AT expression was increased significantly, and proteolytic enzymes from neutrophils, such as neutrophil elastase, myeloperoxidase and lysozyme, were also secreted abundantly in influenza virus and S. pneumoniae co-infected lungs compared with S. pneumoniae or influenza virus singly infected lungs. These data suggest that A1AT may play a central role as a molecule with broad anti-inflammatory properties, and regulation of the neutrophil-mediated severe lung inflammation is important in the pathogenesis of co-infection with influenza virus and bacteria.
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PMID:Two-dimensional gel electrophoresis analysis in simultaneous influenza pneumonia and bacterial infection in mice. 1834 13

Heavy oil contamination is one of the most important environmental issues. Toxicities of polycyclic aromatic hydrocarbons (PAHs), including immune toxicities, are well characterized, however, the immune toxic effects of heavy oil, as a complex mixture of PAHs, have not been investigated. In the present study, we selected Japanese flounder (Paralichthys olivaceus) as a model organism, and observed alteration of immune function by the exposure to heavy oil. To analyze the expression profiles of immune system-related genes, we selected 309 cDNAs from our flounder EST library, and spotted them on a glass slide. Using this cDNA array, alteration of gene expression profiles was analyzed in the kidneys of flounders exposed to heavy oil. Six Japanese flounders (mean body weight: 197 g) were acclimated to laboratory conditions at 19-20 degrees C. Three fish were exposed to heavy oil C (bunker C) at a concentration of 3.8 g/L for 3 days, and the others were kept in seawater without heavy oil and used as the control. After the exposure period, the fish were transferred into control seawater and maintained for 4 days, and then they were dissected and their kidneys were removed. Total RNA was extracted from the kidney samples to use in gene expression analyses. The microarray detected alteration of immune system-related genes in the kidneys of heavy oil-exposed flounders, including down-regulation of immunoglobulin light chain, CD45, major histocompatibility complex class II antigens and macrophage colony-stimulating factor precursor, and up-regulation of interleukin-8 and lysozyme. These results suggest that pathogen resistance may be weakened in heavy oil-exposed fish, causing a subsequent bacterial infection, and then proinflammatory genes may be induced as a defensive response against the infection. Additionally, we found candidate genes for use as biomarkers of heavy oil exposure, such as N-myc downstream regulated gene 1 and heat shock cognate 71 kDa proteins.
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PMID:Toxicogenomic analysis of immune system-related genes in Japanese flounder (Paralichthys olivaceus) exposed to heavy oil. 1838 Dec 19

Lysozyme is an important molecule of innate immune system for the defense against bacterial infections. We identified two genes encoding g-type and c-type lysozymes from grass carp Ctenopharyngodon idellus by the RACE method. The deduced amino acids of both lysozymes possessed typical structural residues and conserved catalytic sites similar to their counterparts across the species. In contrast, there was only 8.6% similarity of amino acid sequence between these two lysozymes. Phylogenetic analyses revealed that these two genes evolved at different rate. C-type lysozyme of grass carp was diverged early in the evolutionary history. Moreover, the expression patterns of these two genes differed. The mRNA levels of both genes were increased after bacterial infection, but the up-regulation of g-type lysozyme was much stronger than that of c-type lysozyme. We also showed that the c-type and g-type recombinant lysozymes possessed different lytic activities against fish bacterial pathogens. These results confirmed that both lysozymes play important roles in the defense of grass carp against bacterial infections. The g-type lysozyme may be induced for the defense against bacterial infections, while c-type lysozyme might be the main molecule for the house-keeping defense under normal conditions. These two types of lysozymes likely use different mechanisms to regulate their expressions.
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PMID:Identification and expression analysis of the g-type and c-type lysozymes in grass carp Ctenopharyngodon idellus. 2003 15

The molecular processes of immune responses in mucosal tissues, such as the gills, during infection with bacterial pathogens are poorly understood. In the present study, we analyzed the transcriptional profiles of selected antibacterial genes and cytokines in the gills of a cold-water fish, Atlantic cod, Gadus morhua following in vitro infection with bacterial pathogens, Vibrio anguillarum and atypical Aeromonas salmonicida using semi-quantitative RT-PCR. There was significant upregulation in the transcripts of the antibacterial genes: bactericidal permeability-increasing protein/lipopolysaccharide-binding protein (BPI/LBP), g-type lysozyme, transferrin, metallothionein, galectin and hepcidin at 3h post-incubation with the two pathogens. The expression of cathelicidin in the gills was significantly enhanced by A. salmonicida, but not by V. anguillarum. At 24h post-incubation, most of these genes were still significantly upregulated, although some genes returned to their basal expression levels. The transcription levels of cytokines such as interleukin (IL)-1beta, IL-8 and interferon (IFN)-gamma significantly increased at 3h post-incubation with the pathogens. IL-22 and CC-chemokine type 1 transcripts were enhanced by A. salmonicida, but not by V. anguillarum. There was down-regulation of expression in CC-chemokine type-2 and -3 by V. anguillarum, while the expression levels of IL-10 remained unchanged upon infection with either of the two bacterial pathogens. The early upregulation of antibacterial genes in the gills could signal the onset of the acute phase response following bacterial infection and the differential modulation of some cytokine genes could be related to host-pathogen interactions that trigger immune response cascades in mucosal tissues of the host.
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PMID:Infection-induced changes in expression of antibacterial and cytokine genes in the gill epithelial cells of Atlantic cod, Gadus morhua during incubation with bacterial pathogens. 2043 Jan 8


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