共查询到10条相似文献,搜索用时 187 毫秒
1.
Yanjing Xiao Austin L Hughes Junko Ando Yoichi Matsuda Jan-Fang Cheng Donald Skinner-Noble Guolong Zhang 《BMC genomics》2004,5(1):56-11
Background
Defensins comprise a large family of cationic antimicrobial peptides that are characterized by the presence of a conserved cysteine-rich defensin motif. Based on the spacing pattern of cysteines, these defensins are broadly divided into five groups, namely plant, invertebrate, α-, β-, and θ-defensins, with the last three groups being mostly found in mammalian species. However, the evolutionary relationships among these five groups of defensins remain controversial. 相似文献2.
Defensins are moonlighting peptides which are broadly distributed throughout all the living kingdoms. They play a multitude of important roles in human health and disease, possessing several immunoregulatory functions and manifesting broad antimicrobial activities against viruses, bacteria, and fungi. Based on their patterns of intramolecular disulfide bridges, these small cysteine-rich cationic proteins are divided into three major types, α-, β-, and θ-defensins, with the α- and β-defensins being further subdivided into a number of subtypes. The various roles played by the defensins in the innate (especially mucosal) and adoptive immunities place these polypeptides at the frontiers of the defense against the microbial invasions. Current work analyzes the antimicrobial activities of human and animal defensins in light of their intrinsic disorder propensities. 相似文献
3.
Gillian M. Morrison Donald J. Davidson Fiona M. Kilanowski Duncan W. Borthwick Ken Crook Alison I. Maxwell John R.W. Govan Julia R. Dorin 《Mammalian genome》1998,9(6):453-457
Defensin are 3–4 kDa antimicrobial peptides of which three distinct families have been identified; α-defensin, β-defensins,
and insect defensins. Recent investigations have shown that β-defensins are present in the human airways and may be relevant
to the pathogenesis of cystic fibrosis (CF) lung disease. We report here the further characterization of a recently identified
mouse β-defensin gene, Defb1, sometimes referred to as mBD-1, which is homologous to the human airway beta defensin hBD-1. We report that Defb1 is expressed in a variety of tissues including the airways and, similar to hBD-1, is not upregulated by lipopolysaccharide (LPS). Defb1 was found to consist of two small exons separated by a 16-kb intron and cytogenetic, and physical mapping linked it to the
alpha defensin gene cluster on mouse Chromosome (Chr) 8. Functional studies demonstrate that, like hBD-1, Defb1 demonstrates
a salt-sensitive antimicrobial activity against Pseudomonas aeruginosa. Of relevance to CF lung disease is the fact that neither the hBD-1 nor the mBD-1 peptides are active against Burkholderia cepacia.
Received: 3 December 1997 / Accepted: 17 February 1998 相似文献
4.
Siegbert Rieg Benjamin Meier Eva Fähnrich Anja Huth Dirk Wagner Winfried V Kern Hubert Kalbacher 《BMC microbiology》2010,10(1):61
Background
Members of the genus Nocardia are ubiquitous environmental saprophytes capable to cause human pulmonary, disseminated and cutaneous nocardiosis or bovine mastitis. Innate immunity appears to play an important role in early defense against Nocardia species. To elucidate the contribution of antimicrobial peptides (AMPs) in innate defense against Nocardia, the activity of human α-defensins human neutrophil peptides (HNPs) 1-3, human β-defensin (hBD)-3 and cathelicidin LL-37 as well as bovine β-defensins lingual and tracheal antimicrobial peptides (LAP, TAP) and bovine neutrophil-derived indolicidin against four important Nocardia species was investigated. 相似文献5.
Fabian Garreis Thomas Schlorf Dieter Worlitzsch Philipp Steven Lars Bräuer Kristin Jäger Friedrich P. Paulsen 《Histochemistry and cell biology》2010,134(1):59-73
Human β-defensins are cationic peptides produced by epithelial cells that have been proposed to be an important component
of immune function at mucosal surfaces. In this study, the expression and inducibility of β-defensins at the ocular surface
were investigated in vitro and in vivo. Expression of human β-defensins (hBD) was determined by RT-PCR and immunohistochemistry
in tissues of the ocular surface and lacrimal apparatus. Cultured corneal and conjunctival epithelial cells were stimulated
with proinflammatory cytokines and supernatants of different ocular pathogens. Real-time PCR and ELISA experiments were performed
to study the effect on the inducibility of hBD2 and 3. Expression and inducibility of mouse β-defensins-2, -3 and -4 (mBD2–4)
were tested in a mouse ocular surface scratch model with and without treatment of supernatants of a clinical Staphylococcus aureus (SA) isolate by means of immunohistochemistry. Here we show that hBD1, -2, -3 and -4 are constitutively expressed in conjunctival
epithelial cells and also partly in cornea. Healthy tissues of the ocular surface, lacrimal apparatus and human tears contain
measurable amounts of hBD2 and -3, with highest concentrations in cornea and much lower concentrations in all other tissues,
especially tears, suggesting intraepithelial storage of β-defensins. Exposure of cultured human corneal and conjunctival epithelial
cells to proinflammatory cytokines and supernatants of various bacteria revealed that IL-1β is a very strong inductor of hBD2
and Staphylococcus aureus increases both hBD2 and hBD3 production in corneal and conjunctival epithelial cells. A murine corneal scratch model demonstrated
that β-defensins are only induced if microbial products within the tear film come into contact with a defective epithelium.
Our finding suggests that the tear film per se contains so much antimicrobial substances that epithelial induction of β-defensins
occurs only as a result of ocular surface damage. These findings widen our knowledge of the distribution, amount and inducibility
of β-defensins at the ocular surface and lacrimal apparatus and show how β-defensins are regulated specifically. 相似文献
6.
Evidence for myxobacterial origin of eukaryotic defensins 总被引:1,自引:0,他引:1
Zhu S 《Immunogenetics》2007,59(12):949-954
Antimicrobial defensins with the cysteine-stabilized α-helical and β-sheet (CSαβ) motif are a large family of ancient, evolutionarily
related innate immunity effectors of multicellular organisms. Although the widespread distribution in plants, fungi, and invertebrates
suggests their uniqueness to Eukarya, it is unknown whether these eukaryotic defensins originated before or posterior to the
emergence of eukaryotes. In this study, we provide evidence in support of the existence of defensin-like peptides (DLPs) in
myxobacteria based on structural bioinformatics analysis, which recognized two bacterial peptides with a conserved cysteine-stabilized
α-helical motif, a nested structural unit of the CSαβ motif. Similarity in sequence and structure to fungal DLPs together
with restricted distribution to the myxobacteria as well as central role of the myxobacteria in the origin of eukaryotes suggest
that the bacterial DLPs represent the ancestor of the eukaryotic defensins and could mediate immune defense of early eukaryotes
after gene transfer to the proto-eukaryotic genome. Our work thus offers a basis for further investigation of prokaryotic
origin of eukaryotic immune effector molecules.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
7.
Yongming Sang Amar A. Patil Guolong Zhang Chris R. Ross Frank Blecha 《Mammalian genome》2006,17(4):332-339
β-Defensins are a major group of mammalian antimicrobial peptides. Although more than 30 β-defensins have been identified
in humans, only one porcine β-defensin has been reported. In this article we report the identification and initial characterization
of 11 novel porcine β-defensins (pBD). Using bioinformatic approaches, we screened 287,821 porcine expressed sequence tags
for similarity of their predicted peptides to known human β-defensins and identified full-length or partial sequences for
the 11 novel pBDs. Similar to the previously identified pBD1, all of these peptides have a consensus β-defensin motif. A differential
expression pattern for these newly identified genes was found. For example, unlike most β-defensins, pBD2 and pBD3 were expressed in bone marrow and in other lymphoid tissues including thymus, spleen, lymph nodes, duodenum, and liver. Including
pBD2 and pBD3, six porcine β-defensins were expressed in lung and skin. Several newly identified porcine β-defensins, including pBD123, pBD125, and pBD129, were expressed in male reproductive tissues, including lobuli testis and some segments of the epididymis. Phylogenetic analysis
indicates that in most cases the evolutionary relationship between individual porcine β-defensins and their human orthologs
is closer than the relationship among β-defensins in the same species. These findings establish the existence of multiple
porcine β-defensins and suggest that the pig may be an ideal model for the characterization of β-defensin diversity and function.
The nucleotide sequence data reported in this article have been submitted to GenBank. 相似文献
8.
Bals R 《Respiratory research》2000,1(3):141-150
One component of host defense at mucosal surfaces seems to be epithelium-derived antimicrobial peptides. Antimicrobial peptides are classified on the basis of their structure and amino acid motifs. Peptides of the defensin, cathelicidin, and histatin classes are found in humans. In the airways, α-defensins and the cathelicidin LL-37/hCAP-18 originate from neutrophils. β-Defensins and LL-37/hCAP-18 are produced by the respiratory epithelium and the alveolar macrophage and secreted into the airway surface fluid. Beside their direct antimicrobial function, antimicrobial peptides have multiple roles as mediators of inflammation with effects on epithelial and inflammatory cells, influencing such diverse processes as proliferation, immune induction, wound healing, cytokine release, chemotaxis, protease-antiprotease balance, and redox homeostasis. Further, antimicrobial peptides qualify as prototypes of innovative drugs that might be used as antibiotics, anti-lipopolysaccharide drugs, or modifiers of inflammation. 相似文献
9.
Functional interaction of human neutrophil peptide-1 with the cell wall precursor lipid II 总被引:1,自引:0,他引:1
Defensins constitute a major class of cationic antimicrobial peptides in mammals and vertebrates, acting as effectors of innate immunity against infectious microorganisms. It is generally accepted that defensins are bactericidal by disrupting the anionic microbial membrane. Here, we provide evidence that membrane activity of human α-defensins does not correlate with antibacterial killing. We further show that the α-defensin human neutrophil peptide-1 (HNP1) binds to the cell wall precursor lipid II and that reduction of lipid II levels in the bacterial membrane significantly reduces bacterial killing. The interaction between defensins and lipid II suggests the inhibition of cell wall synthesis as a novel antibacterial mechanism of this important class of host defense peptides. 相似文献
10.
Expression and polymorphism of defensins in farm animals 总被引:1,自引:0,他引:1
Bagnicka E Strzałkowska N Jóźwik A Krzyżewski J Horbańczuk J Zwierzchowski L 《Acta biochimica Polonica》2010,57(4):487-497