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Antimicrobial peptides

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https://www.readbyqxmd.com/read/28811680/the-antimicrobial-peptide-human-beta-defensin-3-is-induced-by-platelet-released-growth-factors-in-primary-keratinocytes
#1
Andreas Bayer, Justus Lammel, Mersedeh Tohidnezhad, Sebastian Lippross, Peter Behrendt, Tim Klüter, Thomas Pufe, Jochen Cremer, Holger Jahr, Franziska Rademacher, Regine Gläser, Jürgen Harder
Platelet-released growth factors (PRGF) and its related clinically used formulations (e.g., Vivostat Platelet-Rich Fibrin (PRF®)) contain a variety of chemokines, cytokines, and growth factors and are therefore used to support healing of chronic, hard-to-heal, or infected wounds. Human beta-defensin-3 (hBD-3) is an antimicrobial peptide inducibly expressed in human keratinocytes especially upon wounding. The potent antimicrobial activity of hBD-3 together with its wound closure-promoting activities suggests that hBD-3 may play a crucial role in wound healing...
2017: Mediators of Inflammation
https://www.readbyqxmd.com/read/28811617/cell-surface-binding-uptaking-and-anticancer-activity-of-l-k6-a-lysine-leucine-rich-peptide-on-human-breast-cancer-mcf-7-cells
#2
Che Wang, Shaodan Dong, Lin Zhang, Ying Zhao, Lili Huang, Xiange Gong, He Wang, Dejing Shang
Cell surface binding and internalization are critical for the specific targeting and biofunctions of some cationic antimicrobial peptides (CAPs) with anticancer activities. However, the detailed cellular process for CAPs interacting with cancer cells and the exact molecular basis for their anticancer effects are still far from being fully understood. In the present study, we examined the cell surface binding, uptaking and anti-cancer activity of L-K6, a lysine/leucine-rich CAP, in human MCF-7 breast cancer cells...
August 15, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28811193/a-novel-detection-procedure-for-mutations-in-the-23s-rrna-gene-of-mycoplasma-pneumoniae-with-peptide-nucleic-acid-mediated-loop-mediated-isothermal-amplification-assay
#3
Jun Sakai, Takuya Maeda, Norihito Tarumoto, Kazuhisa Misawa, Shinsuke Tamura, Kazuo Imai, Toshiyuki Yamaguchi, Satoshi Iwata, Takashi Murakami, Shigefumi Maesaki
Rapid and easy detection of a single nucleotide point mutation of bacterial genes, which is directly linked to drug susceptibility, is essential for the proper use of antimicrobial agents. Here, we established a detection method using a peptide nucleic acid mediated loop-mediated amplification (LAMP) assay for macrolide (ML)-susceptible Mycoplasma pneumoniae. This assay specifically detected the absence of missense mutations encoding the central loop of domain V in the gene encoding 23S rRNA, which can reduce the affinity for MLs and subsequently generate ML-resistant strains of M...
August 12, 2017: Journal of Microbiological Methods
https://www.readbyqxmd.com/read/28808155/roca-is-an-accessory-protein-to-the-virulence-regulating-covr-s-two-component-system-in-the-group-a-streptococcus
#4
Ira Jain, Eric W Miller, Jessica L Danger, Kathryn J Pflughoeft, Paul Sumby
Regulating gene expression during infection is critical to the ability of pathogens to circumvent the immune response and cause disease. This is true for the group A Streptococcus (GAS), a pathogen that causes both invasive (e.g. necrotizing fasciitis) and non-invasive (e.g. pharyngitis) diseases. The control of virulence (CovR/S) two-component system has a major role in regulating GAS virulence factor expression. The regulator of cov (RocA) protein, which is a predicted kinase, functions in an undetermined manner through CovR/S to alter gene expression and reduce invasive disease virulence...
August 14, 2017: Infection and Immunity
https://www.readbyqxmd.com/read/28807840/the-heterologous-expression-strategies-of-antimicrobial-peptides-in-microbial-systems
#5
REVIEW
Ting Deng, Haoran Ge, Huahua He, Yao Liu, Chao Zhai, Liang Feng, Li Yi
Antimicrobial peptides (AMPs) consist of molecules acting on the defense systems of numerous organisms toward tumor and multiple pathogens, such as bacteria, fungi, viruses, and parasites. Compared to traditional antibiotics, AMPs are more stable and have lower propensity for developing resistance through functioning in the innate immune system, thus having important applications in the fields of medicine, food and so on. However, despite of their high economic values, the low yield and the cumbersome extraction process in AMPs production are problems that limit their industrial application and scientific research...
August 11, 2017: Protein Expression and Purification
https://www.readbyqxmd.com/read/28807783/aggregation-and-its-influence-on-the-immunomodulatory-activity-of-synthetic-innate-defense-regulator-peptides
#6
Evan F Haney, Bing Catherine Wu, Kelsey Lee, Ashley L Hilchie, Robert E W Hancock
There is increasing interest in developing cationic host defense peptides (HDPs) and their synthetic derivatives as antimicrobial, immunomodulatory, and anti-biofilm agents. These activities are often evaluated without considering biologically relevant concentrations of salts or serum; furthermore certain HDPs have been shown to aggregate in vitro. Here we examined the effect of aggregation on the immunomodulatory activity of a synthetic innate defense regulator peptide, 1018 (VRLIVAVRIWRR-NH2). A variety of salts and solutes were screened to determine their influence on 1018 aggregation, revealing that this peptide "salts out" of solution in an anion-specific and concentration-dependent manner...
July 24, 2017: Cell Chemical Biology
https://www.readbyqxmd.com/read/28807561/mass-spectrometry-analysis-of-intact-francisella-bacteria-identifies-lipid-a-structure-remodeling-in-response-to-acidic-ph-stress
#7
Camille B Robert, Michael Thomson, Alain Vercellone, Francesca Gardner, Robert K Ernst, Gérald Larrouy-Maumus, Jérôme Nigou
Structural modification of lipid A, the lipid anchor of LPS, is one of the strategies used by Gram-negative bacteria to evade host innate immunity. Francisella tularensis is a human pathogen that infects and replicates within phagocytic cells. It produces an atypical lipid A, whose structure precludes an efficient recognition by both innate immune players, TLR4 and cationic antimicrobial peptides. Interestingly, a recent report indicates that the lipid A of Francisella (LVS vaccinal strain) undergoes polar modifications when bacteria are grown in human macrophages as compared to in broth...
August 11, 2017: Biochimie
https://www.readbyqxmd.com/read/28805711/a-dereplication-and-bioguided-discovery-approach-to-reveal-new-compounds-from-a-marine-derived-fungus-stilbella-fimetaria
#8
Sara Kildgaard, Karolina Subko, Emma Phillips, Violaine Goidts, Mercedes de la Cruz, Caridad Díaz, Charlotte H Gotfredsen, Birgitte Andersen, Jens C Frisvad, Kristian F Nielsen, Thomas O Larsen
A marine-derived Stilbella fimetaria fungal strain was screened for new bioactive compounds based on two different approaches: (i) bio-guided approach using cytotoxicity and antimicrobial bioassays; and (ii) dereplication based approach using liquid chromatography with both diode array detection and high resolution mass spectrometry. This led to the discovery of several bioactive compound families with different biosynthetic origins, including pimarane-type diterpenoids and hybrid polyketide-non ribosomal peptide derived compounds...
August 13, 2017: Marine Drugs
https://www.readbyqxmd.com/read/28805387/polymyxin-binding-to-the-bacterial-outer-membrane-reveals-cation-displacement-and-increasing-membrane-curvature-in-susceptible-but-not-in-resistant-lps-chemotypes
#9
Denys Ewerton da Silva Santos, Laércio Pol-Fachin, Roberto D Lins, Thereza A Soares
Lipid-A is the causative agent of Gram-negative sepsis and responsible for increasingly high mortality rate among hospitalized patients. Compounds that bind Lipid-A can limit this inflammatory process. The cationic antimicrobial peptide polymyxin B (Pmx-B) is one of the simplest molecules capable of selectively bind to Lipid-A, and may serve as a model for further development of Lipid-A binding agents. Gram-negative bacteria resistance to Pmx-B relies on the upregulation of a number of regulatory systems, which promote chemical modifications of the LPS structure, and leads to major changes in the physical-chemical properties of the outer membrane...
August 14, 2017: Journal of Chemical Information and Modeling
https://www.readbyqxmd.com/read/28804554/effect-of-omiganan-on-colonic-anastomosis-healing-in-a-rat-model-of-peritonitis
#10
Teresa Lorenzi, Maria Michela Cappelletti Trombettoni, Roberto Ghiselli, Francesca Paolinelli, Rosaria Gesuita, Oscar Cirioni, Mauro Provinciali, Wojciech Kamysz, Elzbieta Kamysz, Cristiano Piangatelli, Mario Castellucci Md, Mario Guerrieri, Manrico Morroni
BACKGROUND: This study investigates the effects of the antimicrobial cationic peptide omiganan-alone and combined with the antibiotic imipenem-on colonic anastomosis healing in presence of intraperitoneal sepsis induced in a rodent model of cecal ligation and puncture (CLP). METHODS: Forty male Wistar rats were divided into 5 groups of 8 animals. Group 1 (control group) underwent laparotomy and cecal mobilization and the next day received left colon anastomosis...
2017: American Journal of Translational Research
https://www.readbyqxmd.com/read/28804478/the-entomopathogenic-fungi-isaria-fumosorosea-plays-a-vital-role-in-suppressing-the-immune-system-of-plutella-xylostella-rna-seq-and-dge-analysis-of-immunity-related-genes
#11
Jin Xu, Xiaoxia Xu, Muhammad Shakeel, Shuzhong Li, Shuang Wang, Xianqiang Zhou, Jialin Yu, Xiaojing Xu, Xiaoqiang Yu, Fengliang Jin
Most, if not all, entomopathogenic fungi have been used as alternative control agents to decrease the insect resistance and harmful effects of the insecticides on the environment. Among them, Isaria fumosorosea has also shown great potential to control different insect pests. In the present study, we explored the immune response of P. xylostella to the infection of I. fumosorosea at different time points by using RNA-Sequencing and differential gene expression technology at the genomic level. To gain insight into the host-pathogen interaction at the genomic level, five libraries of P...
2017: Frontiers in Microbiology
https://www.readbyqxmd.com/read/28803959/thymosin-%C3%AE-4-is-involved-in-the-antimicrobial-immune-response-of-golden-pompano-trachinotus-ovatus
#12
Yun Sun, Xiaojuan Chen, Yue Xu, Qiaohong Liu, Xue Jiang, Shifeng Wang, Weiliang Guo, Yongcan Zhou
Thymosin beta belongs to the thymosin family, which consists of a series of highly conserved peptides involved in various biological processes. In teleosts, understanding of the immunological functions of thymosin beta is limited, particularly in vivo, which is essentially unknown. In the current study, we cloned and identified thymosin beta 4 from the teleost fish Golden pompano (Trachinotus ovatus), which we have named TroTβ4. We investigated the expression patterns and functions of TroTβ4 in both in vivo and in vitro assays...
August 10, 2017: Fish & Shellfish Immunology
https://www.readbyqxmd.com/read/28802397/lysx-gene-is-differentially-expressed-among-mycobacterium-tuberculosis-strains-with-different-levels-of-virulence
#13
Alejandra Montoya-Rosales, Roberta Provvedi, Flor Torres-Juarez, Jose A Enciso-Moreno, Rogelio Hernandez-Pando, Riccardo Manganelli, Bruno Rivas-Santiago
Antimicrobial peptides (AMPs) are mainly produced by epithelial cells and macrophages to eliminate infecting mycobacteria through direct antimicrobial activity and immunomodulation. Indeed, it has been described that this line of defense is essential to control infection. However, Mycobacterium tuberculosis (Mtb) has developed mechanisms to avoid AMPs activity, for instance lysX adds lysine residues to surface phospholipids changing their net charge, leading to the repelling of the AMPs. In the present study, we determined that lysX gene is differentially expressed among Mtb strains...
September 2017: Tuberculosis
https://www.readbyqxmd.com/read/28802058/postantibiotic-effect-and-postantibiotic-sub-mic-effect-of-ltx-109-and-mupirocin-on-staphylococcus-aureus-blood-isolates
#14
Louis D Saravolatz, Joan Pawlak, Hayley Martin, Stephanie Saravolatz, Leonard Johnson, Hedda Wold, Mette Husbyn, Wenche Marie Olsen
The development of new synthetic antimicrobial peptides like LTX-109 provides a new class of drugs for the treatment of Staphylococcus aureus infections. We evaluated LTX-109 and mupirocin for pharmacodynamic parameters against 10 methicillin-resistant S. aureus isolates. The post antibiotic effect (PAE) is defined as the length of time that bacterial growth is suppressed following a brief exposure to an antibiotic. We also determined the sub-MIC effect (SME) which measures the direct effect of sub-inhibitory levels on strains that have not previously been exposed to antibiotics...
August 12, 2017: Letters in Applied Microbiology
https://www.readbyqxmd.com/read/28802004/comparison-of-antimicrobial-peptide-purification-via-free-flow-electrophoresis-and-gel-filtration-chromatography
#15
Zhi-Jun Xia, Zhen Liu, Fan-Zhi Kong, Liu-Yin Fan, Hua Xiao, Cheng-Xi Cao
Antimicrobial peptides (AMPs) are usually small and cationic biomolecules with broad-spectrum antimicrobial activities against pathogens. Purifying them from complex samples is essential to study their physiochemical properties. In this work, free-flow zone electrophoresis (FFZE) was utilized to purify antimicrobial peptides from yeast fermentation broth. Meanwhile, gel filtration chromatography (GFC) was conducted for comparison. The separation efficiency was evaluated by SDS-PAGE analysis of the fractions from both methods...
August 12, 2017: Electrophoresis
https://www.readbyqxmd.com/read/28801228/identification-of-the-first-cathelicidin-gene-from-skin-of-chinese-giant-salamanders-andrias-davidianus-with-its-potent-antimicrobial-activity
#16
Hui Yang, Baoyue Lu, Dandan Zhou, Lin Zhao, Weijia Song, Lixin Wang
Cathelicidins, as effector molecules, play important roles against infections and represent a crucial component of the innate immune system in vertebrates. They are widely studied in mammals, but little is known in amphibians. In the present study, we report the identification and characterization of a novel cathelicidin from Chinese giant salamander Andrias davidianus, which is the first study in Caudata amphibian. The cDNA sequence encodes a predicted 148-amino-acid polypeptide, which composed of a 20-residue signal peptide, a 94-residue conserved cathelin domain and a 34-residue mature peptide...
August 9, 2017: Developmental and Comparative Immunology
https://www.readbyqxmd.com/read/28798159/as-cath1-6-novel-cathelicidins-with-potent-antimicrobial-and-immunomodulatory-properties-from-alligator-sinensis-play-pivotal-roles-in-host-antimicrobial-immune-responses
#17
Yan Chen, Shasha Cai, Xue Qiao, Mali Wu, Zhilai Guo, Renping Wang, Yi-Qun Kuang, Haining Yu, Yipeng Wang
Crocodilians are regarded as possessing a powerful immune system. However, the composition and action of the crocodilian immune system have remained unclear until now. Cathelicidins, the principal family of host defense peptides, play pivotal roles in vertebrate immune defense against microbial invasions. However, cathelicidins from crocodilians have not been extensively studied to date. In the present study, six novel cathelicidins (As-CATH1-6) were identified and characterized from the endangered Chinese alligator (Alligator sinensis)...
August 10, 2017: Biochemical Journal
https://www.readbyqxmd.com/read/28797773/methyl-propiolate-and-3-butynone-starting-points-for-synthesis-of-amphiphilic-1-2-3-triazole-peptidomimetics-for-antimicrobial-evaluation
#18
Thomas A Bakka, Morten B Strøm, Jeanette H Andersen, Odd R Gautun
A library of 29 small 1,4-substituted 1,2,3-triazoles was prepared for studies of antimicrobial activity. The pharmacophore model investigated with these substrates was based on small peptidomimetics of antimicrobial peptides and antimicrobials isolated from marine organisms from sub-arctic regions. Using methyl 1,2,3-triazole-carboxylates and 1,2,3-triazole methyl ketones prepared through "click" chemistry we were able to synthesize the different cationic amphiphiles through three steps or less. Several structural modifications to the lipopohilic side and hydrophilic sides of the amphiphiles were investigated and compared with regards to antimicrobial activity and cytotoxicity in particular...
July 29, 2017: Bioorganic & Medicinal Chemistry
https://www.readbyqxmd.com/read/28797092/studies-of-the-antitumor-mechanism-of-action-of-dermaseptin-b2-a-multifunctional-cationic-antimicrobial-peptide-reveal-a-partial-implication-of-cell-surface-glycosaminoglycans
#19
Célia Dos Santos, Sabah Hamadat, Karen Le Saux, Clara Newton, Meriem Mazouni, Loussiné Zargarian, Mickael Miro-Padovani, Patricia Zadigue, Jean Delbé, Yamina Hamma-Kourbali, Mohamed Amiche
Dermaseptin-B2 (DRS-B2) is a multifunctional cationic antimicrobial peptide (CAP) isolated from frog skin secretion. We previously reported that DRS-B2 possesses anticancer and antiangiogenic activities in vitro and in vivo. In the present study, we evaluated the antiproliferative activity of DRS-B2 on numerous tumor cell lines, its cell internalization and studies of its molecular partners as well as their influences on its structure. Confocal microscopy using ([Alexa594]-(Cys0)-DRS-B2) shows that in sensitive human tumor cells (PC3), DRS-B2 seems to accumulate rapidly at the cytoplasmic membranes and enters the cytoplasm and the nucleus, while in less sensitive tumor cells (U87MG), DRS-B2 is found packed in vesicles at the cell membrane...
2017: PloS One
https://www.readbyqxmd.com/read/28796463/defensin-neurotoxin-dyad-in-a-basally-branching-metazoan-sea-anemone
#20
Chan-Hee Kim, Ye Jin Lee, Hye-Jin Go, Hye Young Oh, Tae Kwan Lee, Ji Been Park, Nam Gyu Park
Recent studies suggest that vertebrate and invertebrate defensins have evolved from two independent ancestors, and that both defensins could share origins with animal toxins. Here, we purified novel sea anemone neurotoxin (BDS)-like antimicrobial peptides (AMPs)-Crassicorin-I and its putative homolog (Crassicorin-II)-from the pharynx extract of an anthozoan sea anemone (Urticina crassicornis). Based on structural analyses and cDNA cloning, mature Crassicorin-I represents a cationic AMP likely generated from a precursor and comprising 40 amino acid residues, including six cysteines forming three intramolecular disulphide bonds...
August 10, 2017: FEBS Journal
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