Invertebrate-type lysozyme

Lysozymes are widely distributed immune effectors exerting muramidase activity against the peptidoglycan of the bacterial cell wall to trigger cell lysis. However, some invertebrate-type (i-type) lysozymes deficient of muramidase activity still exhibit antimicrobial activity. To date, the mechanism underlying the antimicrobial effect of muramidase-deficient i-type lysozymes remains unclear. Accordingly, this study characterized a novel i-type lysozyme, Splys-i, in the mud crab Scylla paramamosain. Splys-i shared the highest identity with the Litopenaeus vannamei i-type lysozyme (Lvlys-i2, 54% identity) at the amino acid level...

Lysozymes play an important role in the innate immune responses with which mollusks respond to bacterial invasion through its lytic activity. In the present study, two c-type lysozymes (designed as VpCLYZ-1 and VpCLYZ-2, respectively) were identified and characterized from the manila clam Venerupis philippinarum. The full-length cDNA of VpCLYZ-1 and VpCLYZ-2 was of 629 and 736 bp, encoding a polypeptide of 156 and153 amino acid residues, respectively. The deduced amino acid sequences of VpCLYZs showed high similarity to other known invertebrate c-type lysozymes...

Cyanobacteria are ubiquitously distributed in water on the Earth. It has long been known that the cyanobacterial bloom in aquaculture ponds can cause acute and massive deaths of shrimp. However, the long-term and chronic effects of the cyanobacterial bloom on shrimp are still poorly understood. In this study, the immune state of white pacific shrimp, Litopenaeus vannamei, surviving a naturally occurring cyanobacterial bloom was investigated and tracked for 70 d. Compared with the control, the growth of shrimp suffering high concentrations of cyanobacteria was obviously postponed...

The xenoestrogen 4-nonylphenol (NP) is a ubiquitous aquatic pollutant and has been shown to impair reproduction, development, growth and, more recently, immune function in marine invertebrates. We investigated the effects of short-term (7 d) exposure to low (2 μg l(-1)) and high (100 μg l(-1)) levels of NP on cellular and humoral elements of the innate immune response of Crassostrea gigas to a bacterial challenge. To this end, we measured 1) total hemocyte counts (THC), 2) relative transcript abundance of ten immune-related genes (defh1, defh2, bigdef1, bigdef2, bpi, lysozyme-1, galectin, C-type lectin 2, timp, and transglutaminase) in the hemocytes, gill and mantle, and 3) hemolymph plasma lysozyme activity, following experimental Vibrio campbellii infection...

Little is known about the relative contributions and importance of antibacterial effectors in the nematode C. elegans, despite extensive work on the innate immune responses in this organism. We report an investigation of the expression, function and regulation of the six ilys (invertebrate-type lysozyme) genes of C. elegans. These genes exhibited a surprising variety of tissue-specific expression patterns and responses to starvation or bacterial infection. The most strongly expressed, ilys-3, was investigated in detail...

Asn46Asp/Asp52Ser or Asn46Glu/Asp52Ser hen egg white lysozyme (HEL) mutant was designed by introducing the substituted catalytic residue Asp46 or Glu46, respectively, based on Venerupis philippinarum (Vp) lysozyme structure as a representative of invertebrate-type (i-type) lyzozyme. These mutations restored the bell-shaped pH-dependency of the enzyme activity from the sigmoidal pH-dependency observed for the Asp52Ser mutant. Furthermore both lysozyme mutants possessed retaining mechanisms like Vp lysozyme and HEL...

The full-length cDNA coding for a novel invertebrate (i-type) lysozyme was identified in Pacific white shrimp (Litopenaeus vannamei). The newly obtained L. vannamei lysozyme is similar to the Penaeus monodon i-type lysozyme 2, but it is distant from the known L. vannamei c-type lysozyme and i-type lysozyme 1 in protein sequence; therefore, it was defined as L. vannamei i-type lysozyme 2 (lyz-i2). Expression of L. vannamei lyz-i2 transcripts were ubiquitously detected in all tissues we selected, with the highest abundance observed in the hemolymph...

In invertebrates, hemocytes play an important role in immune responses. Recently, a novel form of innate immune mechanism called extracellular traps (ETs) was identified in shrimps, where DNA and antimicrobial peptides form complex structure to entrap the invading microbes. In this study, we detected the formation of ETs from hemocytes of kuruma shrimp in response to various stimulations, including phorbol myristate acetate (PMA), lipopolysaccharide (LPS), peptidoglycan (PGN) and Escherichia coli. E. coli cells were also found to be trapped by ET fibers...

Lysozyme (LZ, muramidase, N-acetylmuramylhydrolase) is a protein occuring in animals, plants, bacteria and viruses. It can be found e.g. in granules of neutrophils, macrophages and in serum, saliva, milk, honey and hen egg white. The enzyme hydrolyzes the β-1,4 glycosidic bonds between N-acetylmuramic acid (NAM) and N-acetylglucosamine (NAG) of cell wall peptidoglycan (PG) in Gram-positive and Gram-negative bacteria. In the animal kingdom, three muramidase types have been identified: the c-type (chicken type), the g-type (goose-type) and the i-type (invertebrates)...

PFA (Phalera flavescens agglutinin) lectin purified from larvae of the lobster moth (P. flavescens) shows a strong binding ability specific to the N-acetyllactosamine (Galβ1-4GlcNAc) site. We determined the genomic and cDNA sequences of the PFA gene, which consists of five exons and spans approximately 5 kb of a genomic region. Surprisingly, the amino acid sequence (149 amino acids) was similar to invertebrate-type lysozymes and related proteins. The predicted tertiary structure of the PFA protein was similar to the lysozymes of clams such as the common orient clam (Meretrix lusoria) and Japanese littleneck (Venerupis philippinarum (Tapes japonica))...

The lysozymes identified so far in animals belong to the g-type, c-type, and i-type. Vertebrate animals possess only the former two types, i.e., g- and c-types, while all the three types have been reported in invertebrates. Here we demonstrate that (1) three cDNAs that encode g-, c-, and i-type lysozymes, respectively, were identified in a single species of the amphioxus Branchiostoma japonicum; (2) all the 3-type genes displayed distinct tissue-specific expression pattern; (3) recombinant g-, c-, and i-type lysozymes all exhibited enzymatic activities; and (4) native g-, c-, and i-type lysozymes were identified in the different tissues of amphioxus...

In fish, the first line of defense is represented by the innate immune system and the lysozyme is one of the molecules involved in this mechanism of protection. Three types of lysozymes have been identified in metazoan, the c-type (chicken or conventional), the g-type (goose-type) and the i-type (invertebrate type). They are all involved in the hydrolysation of the bacterial cell wall. Our work has been focused on the molecular characterization, expression analysis by real-time PCR, both at basal condition and after in vivo challenges, and 3D structural studies on the g-type lysozyme from sea bass (Dicentrarchus labrax L...

Lysozyme gene from Fenneropenaeus indicus was cloned, expressed in Escherichia coli and characterized. The cDNA consists of 477 base pairs and encodes amino acid sequence of 159 residues. F. indicus lysozyme had high identity (98%) with Fenneropenaeus merguiensis and Fenneropenaeus chinensis and exhibits low to moderate identities with lysozymes of other invertebrates and vertebrates. This lysozyme is presumed to be chicken types as it possesses two catalytic and eight cysteine residues that are conserved across c-type lysozymes and a c-terminal extension, which is a characteristic of lysozymes from marine invertebrates...

To determine the structure and functional relationships of invertebrate lysozymes, we isolated a new invertebrate (i)-type lysozyme from the common orient clam (Meretrix lusoria) and determined the complete amino acid sequence of two isozymes that differed by one amino acid. The determined sequence showed 65% similarity to a lysozyme from Venerupis philippinarum (Tapes japonica), and it was therefore classified as an i-type lysozyme. The lytic activities of this lysozyme were similar to those of previously reported bivalve i-type lysozymes, but unlike the V...

To evaluate the structure-function relationships of invertebrate lysozymes, a new invertebrate-type (i-type) lysozyme was isolated from the common orient clam (Meretrix lusoria) and the tertiary structure of this enzyme was determined. Comparison of the tertiary structure of this enzyme with those of chicken and Venerupi philippinarum lysozymes revealed that the location of the side chain of the second catalytic residue, an aspartic acid, and the N-acetylglucosamine trimer bound at subsites A-C were different...

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...

Lysozymes are ubiquitously distributed enzymes with hydrolytic activity against bacterial peptidoglycan and function to protect organisms from microbial pathogens. In this study, an invertebrate goose-type lysozyme, designated as abLysG, was identified in the disk abalone, Haliotis discus discus. The full-length cDNA of abLysG was 894 bp in length with an open reading frame of 789 bp encoding a polypeptide of 263 amino acids containing a signal peptide and a characteristic soluble lytic transglycosylase domain...

A c-type lysozyme (named as MgCLYZ) gene was cloned from the mussel Mytilus galloprovincialis. Blast analysis indicated that MgCLYZ was a salivary c-type lysozyme which was mainly found in insects. The nucleotide sequence of MgCLYZ was predicted to encode a polypeptide of 154 amino acid residues with the signal peptide comprising the first 24 residues. The deduced mature peptide of MgCLYZ was of a calculated molecular weight of 14.4 kD and a theoretical isoelectric point (pI) of 8.08. Evolution analysis suggested that bivalve branch of the invertebrate c-type lysozymes phylogeny tree underwent positive selection during evolution...

Lysozyme is an important enzyme in the innate immune system that plays a vital role in fighting microbial infections. In the current study, we identified, cloned, and characterized a gene that encodes an invertebrate-type lysozyme from the disk abalone, Haliotis discus discus (abLysI). The full-length cDNA of abLysI consisted of 545 bp with an open reading frame of 393 bp that encodes 131 amino acids. The theoretical molecular mass of mature abLysI was 12.3 kDa with an isoelectric point of 8.03. Conserved features in other homologs, such as catalytic sites for lytic activity (Glu(30) and Asp(41)), isopeptidase activity (His(107)), and ten cysteine residues were identified in abLysI...

Cyanobacteria have often been described as nutritionally poor for herbivorous organisms. To gain additional information on the potential impacts of invertebrates feeding on cyanobacteria, we fed Elliptio complanata mussels with two types of algae: Anabaena flos-aquae (cyanobacteria) and Pseudokirchneriella subcapitata (green algae). Physiological parameters were examined at the energy status, immune system and oxidative stress levels. Energy status was examined by following the rate of electron transport activity in mitochondria (a measure of cellular energy expense) and lipid/sugar stores in the visceral mass...