Search results for "Antimicrobial Cationic Peptides"
showing 10 items of 37 documents
Temporal patterns in immune responses to a range of microbial insults (Tenebrio molitor).
2008
8 pages; International audience; Much work has elucidated the pathways and mechanisms involved in the production of insect immune effector systems. However, the temporal nature of these responses with respect to different immune insults is less well understood. This study investigated the magnitude and temporal variation in phenoloxidase and antimicrobial activity in the mealworm beetle Tenebrio molitor in response to a number of different synthetic and real immune elicitors. We found that antimicrobial activity in haemolymph increased rapidly during the first 48h after a challenge and was maintained at high levels for at least 14 days. There was no difference in the magnitude of responses …
Individual variability of mytimycin gene expression in mussel
2012
The antifungal peptide mytimycin (MytM) is synthesized by hemocytes of the Mediterranean mussel, Mytilus galloprovincialis. In addition to sequence and gene structure diversities previously reported from pooled hemocytes, the present report focused on the expression of mytm gene in individual M. galloprovincialis, before and after challenge. Within untreated mussel, MytM mRNA was observed by ISH in about 42% of circulating hemocytes, characterized by large, diffuse nucleus. Injection with Fusarium oxysporum increased such percentage, but in only some of the mussels. Similarly, MytM gene expression increased after injection in only some of the mussels, as measured by qPCR. Responders and not…
Antimicrobial Peptides and Their Superior Fluorinated Analogues: Structure-Activity Relationships as Revealed by NMR Spectroscopy and MD Calculations
2010
9 pag., 6 fig, 3 tab.
Established cotton stainer gut bacterial mutualists evade regulation by host antimicrobial peptides
2019
Symbioses with microorganisms are ubiquitous in nature and confer important ecological traits to animal hosts but also require control mechanisms to ensure homeostasis of the symbiotic interactions. In addition to protecting hosts against pathogens, animal immune systems recognize, respond to, and regulate mutualists. The gut bacterial symbionts of the cotton stainer bug, Dysdercus fasciatus, elicit an immune response characterized by the upregulation of c-type lysozyme and the antimicrobial peptide pyrrhocoricin in bugs with their native gut microbiota compared to that in dysbiotic insects. In this study, we investigated the impact of the elicited antimicrobial immune response on the estab…
Identification of the Weevil immune genes and their expression in the bacteriome tissue
2008
Abstract Background Persistent infections with mutualistic intracellular bacteria (endosymbionts) are well represented in insects and are considered to be a driving force in evolution. However, while pathogenic relationships have been well studied over the last decades very little is known about the recognition of the endosymbionts by the host immune system and the mechanism that limits their infection to the bacteria-bearing host tissue (the bacteriome). Results To study bacteriome immune specificity, we first identified immune-relevant genes of the weevil Sitophilus zeamais by using suppressive subtractive hybridization (SSH) and then analyzed their full-length coding sequences obtained b…
Microbiological control of soil-borne phytopathogenic fungi with special emphasis on wilt-inducing Fusarium oxysporum
2009
Contents Summary 529 I. Biological control of plant diseases: state of the art 530 II. Main modes of action of biological control agents 530 III. The protective strains of F. oxysporum: an unexplored model 532 IV. Future directions for the study of the protective capacity of strains of F. oxysporum 539 V. How to make biological control successful in the field? 540 References 541 Summary Plant diseases induced by soil-borne plant pathogens are among the most difficult to control. In the absence of effective chemical control methods, there is renewed interest in biological control based on application of populations of antagonistic micro-organisms. In addition to Pseudomonas spp. a…
N-acyl-homoserine-lactone quorum sensing in tomato phytopathogenic Pseudomonas spp. is involved in the regulation of lipodepsipeptide production
2012
Pseudomonas corrugata and Pseudomonas mediterranea are two closely related phytopathogenic bacteria both causal agents of tomato pith necrosis. P. corrugata produces phytotoxic and antimicrobial cationic lipodepsipeptides (LDPs) which are thought to act as major virulence factors. Previous studies have demonstrated that P. corrugata CFBP 5454 has an N-acyl homoserine lactone (AHL) quorum sensing (QS) system PcoI/PcoR and that LDP production occurs at high population densities. No molecular studies on virulence have thus far been reported for P. mediterranea. In this study, we show that P. mediterranea also produces LDPs as well as possessing an AHL-dependent QS system, designated PmeI/PmeR,…
The host defence peptide LL-37/hCAP-18 is a growth factor for lung cancer cells
2007
Cancer development can be viewed as dysregulated repair. Antimicrobial peptides (AMPs) are effector molecules of the innate immune system with direct antimicrobial activity. Beside this host defence function several AMPs play a role in the regulation of inflammation and tissue repair. The aim of the present study was to investigate whether the human cathelicidin AMP LL-37/hCAP-18 is involved in the biology of lung cancer. Human cancer cell lines were found to express the human cathelicidin LL-37/hCAP-18 mRNA and peptide at different levels. Immunohistochemistry of human lung cancers showed that the peptide is expressed mostly in adenocarcinoma and squamous cell carcinoma. Application of exo…
Overlap and diversity in antimicrobial peptide databases: Compiling a non-redundant set of sequences
2015
Abstract Motivation: The large variety of antimicrobial peptide (AMP) databases developed to date are characterized by a substantial overlap of data and similarity of sequences. Our goals are to analyze the levels of redundancy for all available AMP databases and use this information to build a new non-redundant sequence database. For this purpose, a new software tool is introduced. Results: A comparative study of 25 AMP databases reveals the overlap and diversity among them and the internal diversity within each database. The overlap analysis shows that only one database (Peptaibol) contains exclusive data, not present in any other, whereas all sequences in the LAMP_Patent database are inc…
Heparin-binding protein targeted to mitochondrial compartments protects endothelial cells from apoptosis.
1999
Neutrophil-borne heparin-binding protein (HBP) is a multifunctional protein involved in the progression of inflammation. HBP is stored in neutrophil granules and released upon stimulation of the cells in proximity to endothelial cells. HBP affects endothelial cells in multiple ways; however, the molecular and cellular mechanisms underlying the interaction of HBP with these cells are unknown. Affinity isolation and enzymatic degradation demonstrated that HBP released from human neutrophils binds to endothelial cell-surface proteoglycans, such as syndecans and glypican. Flow cytometry indicated that a significant fraction of proteoglycan-bound HBP is taken up by the endothelial cells, and we …