Fungicidal properties, sterol binding, and proteolytic resistance of the synthetic peptide D4E1

1998 ◽  
Vol 44 (6) ◽  
pp. 514-520 ◽  
Author(s):  
A J De Lucca ◽  
J M Bland ◽  
C Grimm ◽  
T J Jacks ◽  
J W Cary ◽  
...  
Keyword(s):  
Synthetic Peptide ◽  
Fusarium Spp ◽  
Transgenic Expression ◽  
Cecropin A ◽  
Proteolytic Resistance ◽  
Plant Protease ◽  
Physicochemical Studies ◽  
Natural Peptide ◽  
Protease Degradation

The fungicidal properties of the synthetic peptide D4E1 were studied with nongerminated and germinating conidia of Aspergillus flavus, Aspergillus fumigatus, Aspergillus niger, Fusarium moniliforme, and Fusarium oxysporum. The minimal lethal concentrations (MLC) needed to kill 100% of germinating conidia ofA. fumigatus, A. flavus, and A. niger were 12.5, 12.5, and 25 µM, respectively. The MLC value for nongerminated and germinating conidia of both Fusarium spp. was 3.0 µM. Except for A. fumigatus, D4E1 was inactive against the nongerminated conidia of the Aspergillus spp. Physicochemical studies showed D4E1 complexed with ergosterol, a sterol present in conidial walls. Cholesterol, present in nongerminated conidia of F. moniliforme, had a greater affinity for D4E1 than did ergosterol. D4E1 was more resistant to fungal and plant protease degradation than the natural peptide, cecropin A. These in vitro results suggest D4E1 is a candidate for transgenic expression in plants to enhance host resistance to fungal infection.Key words: peptides, fungicidal, Aspergillus spp., Fusarium spp., sterols.

Exploring Galleria mellonella larval model to evaluate antibacterial efficacy of Cecropin A (1-7)- Melittin against multi-drug resistant enteroaggregative Escherichia coli

2021 ◽  
Author(s):  
Jess Vergis ◽  
S V S Malik ◽  
Richa Pathak ◽  
Manesh Kumar ◽  
Nitin V Kurkure ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Galleria Mellonella ◽  
In Vivo Model ◽  
Drug Resistant ◽  
Physiological Concentration ◽  
Microbial Drug Resistance ◽  
Cecropin A ◽  
Screening And Identification

Abstract High throughput in vivo laboratory models is need for screening and identification of effective therapeutic agents to overcome microbial drug-resistance. This study was undertaken to evaluate in vivo antimicrobial efficacy of short-chain antimicrobial peptide- Cecropin A (1–7)-Melittin (CAMA) against three multi- drug resistant enteroaggregative Escherichia coli (MDR-EAEC) field isolates in a Galleria mellonella larval model. The minimum inhibitory concentration (MIC; 2.0 mg/L) and minimum bactericidal concentration (MBC; 4.0 mg/L) of CAMA were determined by microdilution assay. CAMA was found to be stable at high temperatures, physiological concentration of cationic salts and proteases; safe with sheep erythrocytes, secondary cell lines and commensal lactobacilli at lower MICs; and exhibited membrane permeabilisation. In vitro time-kill assay revealed concentration- and time-dependent clearance of MDR-EAEC in CAMA-treated groups at 30 min. CAMA- treated G. mellonella larvae exhibited an increased survival rate, reduced MDR-EAEC counts, immunomodulatory effect and proved non-toxic which concurred with histopathological findings. CAMA exhibited either an equal or better efficacy than the tested antibiotic control, meropenem. This study highlights the possibility of G. mellonella larvae as an excellent in vivo model for investigating the host-pathogen interaction, including the efficacy of antimicrobials against MDR-EAEC strains.

scholarly journals Reversed Proteolysis—Proteases as Peptide Ligases

Catalysts ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 33
Author(s):  
Peter Goettig
Keyword(s):  
Serine Proteases ◽  
Academic Research ◽  
Building Blocks ◽  
Peptide Bond ◽  
Cysteine Proteases ◽  
Small Peptides ◽  
Natural Peptide ◽  
Peptide Esters ◽  
Natural Amino Acids

Historically, ligase activity by proteases was theoretically derived due to their catalyst nature, and it was experimentally observed as early as around 1900. Initially, the digestive proteases, such as pepsin, chymotrypsin, and trypsin were employed to perform in vitro syntheses of small peptides. Protease-catalyzed ligation is more efficient than peptide bond hydrolysis in organic solvents, representing control of the thermodynamic equilibrium. Peptide esters readily form acyl intermediates with serine and cysteine proteases, followed by peptide bond synthesis at the N-terminus of another residue. This type of reaction is under kinetic control, favoring aminolysis over hydrolysis. Although only a few natural peptide ligases are known, such as ubiquitin ligases, sortases, and legumains, the principle of proteases as general catalysts could be adapted to engineer some proteases accordingly. In particular, the serine proteases subtilisin and trypsin were converted to efficient ligases, which are known as subtiligase and trypsiligase. Together with sortases and legumains, they turned out to be very useful in linking peptides and proteins with a great variety of molecules, including biomarkers, sugars or building blocks with non-natural amino acids. Thus, these engineered enzymes are a promising branch for academic research and for pharmaceutical progress.

scholarly journals Effects of Antagonists on Mycotoxins of Seedborne Fusarium spp. in Sweet Corn

Toxins ◽  
2019 ◽  
Vol 11 (8) ◽  
pp. 438
Author(s):  
Mary E. Ridout ◽  
Bruce Godfrey ◽  
George Newcombe
Keyword(s):  
Sweet Corn ◽  
Fusarium Species ◽  
Fusarium Mycotoxins ◽  
Fusarium Spp ◽  
Corn Seed ◽  
Pichia Membranifaciens ◽  
Mature Seeds ◽  
F1 Cross

Fusarium species coexist as toxigenic, systemic pathogens in sweet corn seed production in southwestern Idaho, USA. We hypothesized that fungal antagonists of seedborne Fusarium would differentially alter production of Fusarium mycotoxins directly and/or systemically. We challenged the Fusarium complex by in vitro antagonism trials and in situ silk and seed inoculations with fungal antagonists. Fungal antagonists reduced growth and sporulation of Fusarium species in vitro from 40.5% to as much as 100%. Pichia membranifaciens and Penicillium griseolum reduced fumonisin production by F. verticillioides by 73% and 49%, respectively, while P. membranifaciens and a novel Penicillium sp. (WPT) reduced fumonisins by F. proliferatum 56% and 78%, respectively. In situ, pre-planting inoculation of seeds with Penicillium WPT systemically increased fumonisins in the resulting crop. Morchella snyderi applied to silks of an F1 cross systemically reduced deoxynivalenol by 47% in mature seeds of the F2. Antagonists failed to suppress Fusarium in mature kernels following silk inoculations, although the ratio of F. verticillioides to total Fusarium double with some inoculants. Fusarium mycotoxin concentrations in sweet corn seed change systemically, as well as locally, in response to the presence of fungal antagonists, although in Fusarium presence in situ was not changed.

Further pharmacological evaluation of a novel synthetic peptide bradykinin B2 receptor agonist

2013 ◽  
Vol 394 (3) ◽  
pp. 353-360 ◽  
Author(s):  
Martin Savard ◽  
Julie Labonté ◽  
Céléna Dubuc ◽  
Witold Neugebauer ◽  
Pedro D’Orléans-Juste ◽  
...  
Keyword(s):  
Knockout Mice ◽  
Synthetic Peptide ◽  
Receptor Agonist ◽  
Rabbit Lung ◽  
Hypotensive Action ◽  
Duration Of Action ◽  
Selective Agonist ◽  
Comparable Magnitude

Abstract We recently identified a novel human B2 receptor (B2R) agonist [Hyp3,Thi5,NChg7,Thi8]-bradykinin (NG291) with greater in vitro and in vivo potency and duration of action than natural bradykinin (BK). Here, we further examined its stability and selectivity toward B2R. The hypotensive, antithrombotic, and profibrinolytic functions of NG291 relative to BK and its analogue ([Hyp3,Thi5,(4-Me)Tyr8(ΨCH2NH)Arg9]-BK) (RMP-7) were also tested. Contraction assays using isolated mouse stomachs (containing kinin B1R, B2R, and kininase I- and II-like activities) showed that NG291 is a more potent contractant than BK and is inhibited by HOE-140 (B2R antagonist) but unaffected by R954 (B1R antagonist), whereas both decreased the potency of BK. In stomach tissues from B2R knockout mice, BK maintained its activity via B1R, whereas NG291 had no contractile effect, indicating that it was selective for B2R. Unlike BK, NG291 was not degraded by rabbit lung ACE. Comparing intravenously administered BK and NG291 revealed that NG291 exhibited more potent and prolonged hypotensive action and greater antithrombotic and profibrinolytic activities. These effects were of comparable magnitude to RMP-7 and were absent in B2R knockout mice. We concluded that NG291 is a novel biostable B2R-selective agonist that may prove suitable for investigating the (pre)clinical cardioprotective efficacy of B2R activation.

Transgenic expression of gallerimycin, a novel antifungal insect defensin from the greater wax moth Galleria mellonella, confers resistance to pathogenic fungi in tobacco

2006 ◽  
Vol 387 (5) ◽  
pp. 549-557 ◽  
Author(s):  
Gregor Langen ◽  
Jafargholi Imani ◽  
Boran Altincicek ◽  
Gernot Kieseritzky ◽  
Karl-Heinz Kogel ◽  
...  
Keyword(s):  
Transgenic Tobacco ◽  
Fungal Pathogens ◽  
Galleria Mellonella ◽  
Ectopic Expression ◽  
Pathogenic Fungi ◽  
Transgenic Expression ◽  
Greater Wax Moth ◽  
Insect Defensin ◽  
Wax Moth

Abstract A cDNA encoding gallerimycin, a novel antifungal peptide from the greater wax moth Galleria mellonella, was isolated from a cDNA library of genes expressed during innate immune response in the caterpillars. Upon ectopic expression of gallerimycin in tobacco, using Agrobacterium tumefaciens as a vector, gallerimycin conferred resistance to the fungal pathogens Erysiphe cichoracearum and Sclerotinia minor. Quantification of gallerimycin mRNA in transgenic tobacco by real-time PCR confirmed transgenic expression under control of the inducible mannopine synthase promoter. Leaf sap and intercellular washing fluid from transgenic tobacco inhibited in vitro germination and growth of the fungal pathogens, demonstrating that gallerimycin is secreted into intercellular spaces. The feasibility of the use of gallerimycin to counteract fungal diseases in crop plants is discussed.

Fibrinogen depletion after plasma-dilution: impairment of proteolytic resistance and reversal via clotting factor concentrates

2014 ◽  
Vol 111 (03) ◽  
pp. 417-428 ◽  
Author(s):  
Hans Johnsson ◽  
Michal Zabczyk ◽  
Kjell Hultenby ◽  
Håkan Wallen ◽  
Margareta Blombäck ◽  
...  
Keyword(s):  
Tranexamic Acid ◽  
Clotting Factor ◽  
Clot Lysis ◽  
Trauma Patients ◽  
Fibrinogen Concentrate ◽  
Reversal Effect ◽  
Proteolytic Resistance ◽  
Small Doses ◽  
Fibrinolysis Inhibitor

SummaryIn trauma patients, resuscitation treatment of intravascular volume may cause haemodilution including blood cell- and plasma-dilution. After plasma-dilution, fibrinogen is the first factor that decreases to critically low concentrations. Fibrin formed in lowered levels is susceptible to fibrinolysis, a natural forerunner for bleeding. To assess whether a fibrinogen concentrate or a factor XIII (FXIII) concentrate can reverse the impairment of fibrin properties after plasma dilution, different laboratory methods were used to determine thrombin generation and fibrin quantity/quality in a normal plasma sample diluted in vitro. Coagulation and clot lysis by plasmin were triggered with tissue factor and rt-PA, respectively. We found that while the endogenous thrombin potential (ETP) was unaffected after plasma-dilution due to postponement of thrombin decay, levels of fibrinogen and hence fibrin were decreased in dilution degree-dependency. The imbalance between influence of the dilution on thrombin activity and fibrin formation brought unexpected outcomes of fibrin properties: the formed clots favoured the degradation by plasmin but the fibrin networks remained tighter/less permeable. This proteolytic tendency was partly overturned by the fibrinogen concentrate added (total fibrinogen ≥ 2 g/l), and much more affected if used in combination with tranexamic acid (a fibrinolysis inhibitor) at small doses. No reversal effect resulted from the FXIII concentrate added. We conclude that plasma-dilution did reduce the proteolytic resistance of formed clots. The fibrinogen concentrate, better together with small doses of tranexamic acid, may reverse the impairment of fibrin property. The FXIII concentrate is not effective in this regard in our in vitro model using platelet-poor plasma.

Sign in / Sign up

Export Citation Format

Share Document