Search results for "Antimicrobial cationic peptide"
showing 10 items of 37 documents
cDNA sequence and tissue expression of an antimicrobial peptide, dicentracin; a new component of the moronecidin family isolated from head kidney leu…
2007
A 483-bp cDNA was isolated from sea bass (Dicentrarchus labrax) head kidney leukocytes, dicentracin, using PCR primers designed from conserved moronecidin domains. Gene bank analysis revealed that dicentracin cDNA belongs to the moronecidin family. As deduced from alignment with Morone chrysops moronecidin, the precursor of 79 aa appeared to be composed of a signal peptide of 22 aa, followed by the mature AMP (antimicrobial peptide) of 22 aa named dicentracin, and a C-terminal extension of 35 aa. Dicentracin precursor displayed 3 aa substitutions with other moronecidin sequence but none in the mature peptide sequence. Using in situ hybridization assay, dicentracin gene expression was observ…
Rational Design of a Carrier Protein for the Production of Recombinant Toxic Peptides in Escherichia coli
2016
Commercial uses of bioactive peptides require low cost, effective methods for their production. We developed a new carrier protein for high yield production of recombinant peptides in Escherichia coli very well suited for the production of toxic peptides like antimicrobial peptides. GKY20, a short antimicrobial peptide derived from the C-terminus of human thrombin, was fused to the C-terminus of Onconase, a small ribonuclease (104 amino acids), which efficiently drove the peptide into inclusion bodies with very high expression levels (about 200-250 mg/L). After purification of the fusion protein by immobilized metal ion affinity chromatography, peptide was obtained by chemical cleavage in d…
Gene expression specificity of the mussel antifungal mytimycin (MytM)
2011
Abstract We previously reported the nucleotide sequences and diversity of mytimycin (MytM) from the Mediterranean mussel, Mytilus galloprovincialis. Using real-time PCR (q-PCR), we observed that the MytM gene was mainly expressed in circulating hemocytes and to a less extent in the mantle. In vivo challenge with bacteria or with the yeast, Candida albicans, did not increase the expression as measured by q-PCR in hemocytes. By contrast, injection of the filamentous fungus, Fusarium oxysporum, induced a sudden and strong increase of expression at 9h p.i. (stimulation index of 25.7 ± 2.1). Optimum stimulating dose was 104 spores of F. oxysporum per mussel. In the same samples, AMP mytilin and …
Polymorphism of mytilin B mRNA is not traslated into mature peptide
2008
Diversity of mRNAs from mytilin B, one of the five mytilins identified in the Mediterranean mussel, Mytilus galloprovincialis, has been investigated from circulating hemocytes. One mussel expressed simultaneously two to ten different mytilin B mRNAs as observed in denaturing gradient gel electrophoresis (DGGE), defining 10 individual DGGE patterns (named A to J) within the mussels from Messina, Sicily (Italy). Three patterns accounted for 79% of the individuals whereas other patterns were found in only 2-7% of the 57 analyzed mussels. Base mutations were observed at specific locations, mainly within COOH-terminus and 3'UTR, leading to 36 nucleotide sequence variants and 21 different coding …
The potential of antimicrobial peptides isolated from freshwater crayfish species in new drug development: A review
2021
Abstract The much-publicised increased resistance of pathogenic bacteria to conventional antibiotics has focused research effort on the characterization of new antimicrobial drugs. In this context, antimicrobial peptides (AMPs) extracted from animals are considered a promising alternative to conventional antibiotics. In recent years, freshwater crayfish species have emerged as an important source of bioactive compounds. In fact, these invertebrates rely on an innate immune system based on cellular responses and on the production of important effectors in the haemolymph, such as AMPs, which are produced and stored in granules in haemocytes and released after stimulation. These effectors are …
In vitro induction of cecropin genes — an immune response in a Drosophila blood cell line
1992
The Drosophila melanogaster cell line mbn-2 was explored as a model system to study insect immune responses in vitro. This cell line is of blood cell origin, derived from larval hemocytes of the mutant lethal (2) malignant blood neoplasm (1(2)mbn). The mbn-2 cells respond to microbial substances by the activation of cecropin genes, coding for bactericidal peptides. The response is stronger than that previously described for SL2 cells, and four other tested Drosophila cell lines were totally unresponsive. Bacterial lipopolysaccharide, algal laminarin (a beta-1,3-glucan), and bacterial flagellin were strong inducers, bacterial peptidoglycan fragments gave a weaker response, whereas a formyl-m…
Vibrio vulnificus biotype 2 serovar E gne but not galE is essential for lipopolysaccharide biosynthesis and virulence
2008
ABSTRACT This work aimed to establish the role of gne (encoding UDP-GalNAc 4-epimerase activity) and galE (encoding UDP-Gal-4-epimerase activity) in the biosynthesis of surface polysaccharides, as well as in the virulence for eels and humans of the zoonotic serovar of Vibrio vulnificus biotype 2, serovar E. DNA sequence data revealed that gne and galE are quite homologous within this species (≥90% homology). Mutation in gne of strain CECT4999 increased the surface hydrophobicity, produced deep alterations in the outer membrane architecture, and resulted in noticeable increases in the sensitivity to microcidal peptides (MP), to eel and human sera, and to phagocytosis/opsonophagocytosis. Furt…
The Major Conformational IgE-binding Epitopes of Hevein (Hev b6.02) Are Identified by a Novel Chimera-based Allergen Epitope Mapping Strategy
2002
A novel approach to localize and reconstruct conformational IgE-binding epitope regions of hevein (Hev b6.02), a major natural rubber latex allergen, is described. An antimicrobial protein (AMP) from the amaranth Amaranthus caudatus was used as an immunologically non-IgE-binding adaptor molecule to which terminal or central parts of hevein were fused. Hevein and AMP share a structurally identical core region but have different N-terminal and C-terminal regions. Only 1 of 16 hevein-allergic patients showed weak IgE binding to purified native or recombinant AMP. Chimeric AMP with the hevein N terminus was recognized by IgE from 14 (88%) patients, and chimeric AMP with the hevein C terminus wa…
Construction of hevein (Hev b 6.02) with reduced allergenicity for immunotherapy of latex allergy by comutation of six amino acid residues on the con…
2004
Abstract Recently we have established that IgE Abs bind to conformational epitopes in the N- and C-terminal regions of the major natural rubber latex allergen, hevein (Hev b 6.02). To identify the critical amino acid residues that interact with IgE, the hevein sequence was scanned by using site-specific mutations. Twenty-nine hevein mutants were designed and produced by a baculovirus expression system in insect cells and tested by IgE inhibition-ELISA using sera from 26 latex allergic patients. Six potential IgE-interacting residues of hevein (Arg5, Lys10, Glu29, Tyr30, His35, and Gln38) were identified and characterized further in detail. Based on these six residues, two triple mutants (HΔ…
A trade-off between sexual signalling and immune function in a natural population of the drumming wolf spider Hygrolycosa rubrofasciata.
2005
The field of ecological immunology is ultimately seeking to address the question ‘Why is there variation in immune function?’ Here, we provide experimental evidence that costs of ubiquitous sexual signals are a significant source of variation in immune function. In the mating season, males of the wolf spider Hygrolycosa rubrofasciata drum against dry leaves while wandering around the habitat searching for receptive females. According to a previous study, the male metabolic rate during the drumming increases 22-fold compared to the resting metabolic rate. In the present study, we examined whether investment in costly courtship drumming decreases male immune function in a wild population of H…