scholarly journals Hemolytic Activity in Serum From Leukotic Dogs

1966 ◽  
Vol 7 (1) ◽  
pp. 99-100
Author(s):  
Anders W. Bäckgren ◽  
Peter Unger
Keyword(s):  
Hemolytic Activity

Evaluation of the In Vivo Acute Toxicity and In Vitro Hemolytic and Immunomodulatory Activities of the Moringa oleifera Flower Trypsin Inhibitor (MoFTI)

2020 ◽  
Vol 27 ◽  
Author(s):  
Leydianne Leite de Siqueira Patriota ◽  
Dayane Kelly Dias do Nascimento Santos ◽  
Bárbara Rafaela da Silva Barros ◽  
Lethícia Maria de Souza Aguiar ◽  
Yasmym Araújo Silva ◽  
...  
Keyword(s):  
Acute Toxicity ◽  
Trypsin Inhibitor ◽  
Hemolytic Activity ◽  
Moringa Oleifera ◽  
Biological Activities ◽  
Hematological Parameters ◽  
Behavioral Alterations ◽  
Female Mice

Background: Protease inhibitors have been isolated from plants and present several biological activities, including immunomod-ulatory action. Objective: This work aimed to evaluate a Moringa oleifera flower trypsin inhibitor (MoFTI) for acute toxicity in mice, hemolytic activity on mice erythrocytes and immunomodulatory effects on mice splenocytes. Methods: The acute toxicity was evaluated using Swiss female mice that received a single dose of the vehicle control or MoFTI (300 mg/kg, i.p.). Behavioral alterations were observed 15–240 min after administration, and survival, weight gain, and water and food consumption were analyzed daily. Organ weights and hematological parameters were analyzed after 14 days. Hemolytic activity of MoFTI was tested using Swiss female mice erythrocytes. Splenocytes obtained from BALB/c mice were cultured in the absence or presence of MoFTI for the evaluation of cell viability and proliferation. Mitochondrial membrane potential (ΔΨm) and reactive oxygen species (ROS) levels were also determined. Furthermore, the culture supernatants were analyzed for the presence of cytokines and nitric oxide (NO). Results: MoFTI did not cause death or any adverse effects on the mice except for abdominal contortions at 15–30 min after administration. MoFTI did not exhibit a significant hemolytic effect. In addition, MoFTI did not induce apoptosis or necrosis in splenocytes and had no effect on cell proliferation. Increases in cytosolic and mitochondrial ROS release, as well as ΔΨm reduction, were observed in MoFTI-treated cells. MoFTI was observed to induce TNF-α, IFN-γ, IL-6, IL-10, and NO release. Conclusion: These results contribute to the ongoing evaluation of the antitumor potential of MoFTI and its effects on other immunological targets.

Apoptotic Effects of Melittin on 4T1 Breast Cancer Cell Line is associated with Up Regulation of Mfn1 and Drp1 mRNA Expression

2020 ◽  
Vol 20 (7) ◽  
pp. 790-799 ◽  
Author(s):  
Farnaz D. Moghaddam ◽  
Pejman Mortazavi ◽  
Somayeh Hamedi ◽  
Mohammad Nabiuni ◽  
Nasim H. Roodbari
Keyword(s):  
Breast Cancer ◽  
Mrna Expression ◽  
Hemolytic Activity ◽  
Breast Cancer Cells ◽  
Flow Cytometric Analysis ◽  
Control Group ◽  
Flow Cytometric ◽  
4T1 Cells ◽  
4T1 Breast Cancer ◽  
Apoptotic Effects

Background and Purpose: Melittin, as the main ingredient of honeybee venom, that has shown anticancer properties. The present study aimed at investigating the cytotoxic impacts of melittin on 4T1 breast cancer cells. Methods: Hemolytic activity of different concentrations (0.125, 0.25, 0.5, 1, 2, 4, 8μg/ml) of melittin was assayed and then cytotoxicity of selected concentrations of melittin (2, 4, 8, 16, 32, and 64μg/ml), 2 and 4μg/ml of cisplatin and 0.513, 0.295 and 0.123μg/ml of doxorubicin was evaluated on 4T1 cells using MTT assay. We used Morphological evaluation and flow cytometric analysis was used. Real time PCR was also used to determine mRNA expression of Mfn1 and Drp1 genes. Results: All compounds showed anti-proliferative effects on the tumor cell line with different potencies. Melittin had higher cytotoxicity against 4T1 breast cancer cells (IC50= 32μg/ml-72h) and higher hemolytic activity (HD50= 1μg/ml), as compared to cisplatin and doxorubicin. Mellitin at 16 and 32μg/ml showed apoptotic effects on 4T1 cells according to the flow cytometric analysis. The Real time PCR analysis of Drp1 and Mfn1 expression in cells treated with 16μg/ml of melittin revealed an up-regulation in Drp1 and Mfn1 genes mRNA expression in comparison with control group. Treatment with 32μg/ml of melittin was also associated with a rise in mRNA expression of Drp1 and Mfn1 as compared to the control group. Conclusion: The results of this study showed that melittin has anticancer effects on 4T1 cell lines in a dose and time dependent manner and can be a good candidate for further research on breast cancer treatment.

scholarly journals Development of Antimicrobial Stapled Peptides Based on Magainin 2 Sequence

Molecules ◽  
2021 ◽  
Vol 26 (2) ◽  
pp. 444
Author(s):  
Motoharu Hirano ◽  
Chihiro Saito ◽  
Hidetomo Yokoo ◽  
Chihiro Goto ◽  
Ryuji Kawano ◽  
...  
Keyword(s):  
Antimicrobial Activity ◽  
Amino Acid ◽  
Hemolytic Activity ◽  
Helical Structure ◽  
Antimicrobial Activities ◽  
Side Chain ◽  
Membrane Disruption ◽  
Amino Acid Residues ◽  
Electrophysiological Measurements ◽  
Cell Membrane Disruption

Magainin 2 (Mag2), which was isolated from the skin of the African clawed frog, is a representative antimicrobial peptide (AMP) that exerts antimicrobial activity via microbial membrane disruption. It has been reported that the helicity and amphipathicity of Mag2 play important roles in its antimicrobial activity. We investigated and recently reported that 17 amino acid residues of Mag2 are required for its antimicrobial activity, and accordingly developed antimicrobial foldamers containing α,α-disubstituted amino acid residues. In this study, we further designed and synthesized a set of Mag2 derivatives bearing the hydrocarbon stapling side chain for helix stabilization. The preferred secondary structures, antimicrobial activities, and cell-membrane disruption activities of the synthesized peptides were evaluated. Our analyses revealed that hydrocarbon stapling strongly stabilized the helical structure of the peptides and enhanced their antimicrobial activity. Moreover, peptide 2 stapling between the first and fifth position from the N-terminus showed higher antimicrobial activity than that of Mag2 against both gram-positive and gram-negative bacteria without exerting significant hemolytic activity. To investigate the modes of action of tested peptides 2 and 8 in antimicrobial and hemolytic activity, electrophysiological measurements were performed.

scholarly journals Rational design of novel amphipathic antimicrobial peptides focused on the distribution of cationic amino acid residues

MedChemComm ◽  
2019 ◽  
Vol 10 (6) ◽  
pp. 896-900 ◽  
Author(s):  
Takashi Misawa ◽  
Chihiro Goto ◽  
Norihito Shibata ◽  
Motoharu Hirano ◽  
Yutaka Kikuchi ◽  
...  
Keyword(s):  
Antimicrobial Activity ◽  
Amino Acid ◽  
Human Cell ◽  
Hemolytic Activity ◽  
Rational Design ◽  
Cell Cytotoxicity ◽  
Amino Acid Residues ◽  
High Antimicrobial Activity ◽  
Cationic Amino Acid ◽  
Helical Peptide

Amphipathic helical peptideStripeshowed high antimicrobial activity, low hemolytic activity, and low human cell cytotoxicity.

scholarly journals Antimicrobial Peptide Modifications against Clinically Isolated Antibiotic-Resistant Salmonella

Molecules ◽  
2021 ◽  
Vol 26 (15) ◽  
pp. 4654
Author(s):  
Suthee Mangmee ◽  
Onrapak Reamtong ◽  
Thareerat Kalambaheti ◽  
Sittiruk Roytrakul ◽  
Piengchan Sonthayanon
Keyword(s):  
Antibacterial Activity ◽  
Hemolytic Activity ◽  
Multidrug Resistant ◽  
Terminal Group ◽  
Scorpion Venom ◽  
Antibiofilm Activity ◽  
Peptide Antibiotic ◽  
Dependent Manner ◽  
C Terminus ◽  
Relationship Of

Antimicrobial peptides are promising molecules to address the global antibiotic resistance problem, however, optimization to achieve favorable potency and safety is required. Here, a peptide-template modification approach was employed to design physicochemical variants based on net charge, hydrophobicity, enantiomer, and terminal group. All variants of the scorpion venom peptide BmKn-2 with amphipathic α-helical cationic structure exhibited an increased antibacterial potency when evaluated against multidrug-resistant Salmonella isolates at a MIC range of 4–8 µM. They revealed antibiofilm activity in a dose-dependent manner. Sheep red blood cells were used to evaluate hemolytic and cell selectivity properties. Peptide Kn2-5R-NH2, dKn2-5R-NH2, and 2F-Kn2-5R-NH2 (variants with +6 charges carrying amidated C-terminus) showed stronger antibacterial activity than Kn2-5R (a variant with +5 charges bearing free-carboxyl group at C-terminus). Peptide dKn2-5R-NH2 (d-enantiomer) exhibited slightly weaker antibacterial activity with much less hemolytic activity (higher hemolytic concentration 50) than Kn2-5R-NH2 (l-enantiomer). Furthermore, peptide Kn2-5R with the least hydrophobicity had the lowest hemolytic activity and showed the highest specificity to Salmonella (the highest selectivity index). This study also explained the relationship of peptide physicochemical properties and bioactivities that would fulfill and accelerate progress in peptide antibiotic research and development.

scholarly journals 1202. Subinhibitory Concentrations of Omadacycline Inhibit Staphylococcus aureus Hemolytic Activity in Vitro

2020 ◽  
Vol 7 (Supplement_1) ◽  
pp. S622-S623
Author(s):  
Alisa W Serio ◽  
S Ken Tanaka ◽  
Kelly Wright ◽  
Lynne Garrity-Ryan
Keyword(s):  
Staphylococcus Aureus ◽  
Protein Synthesis ◽  
Virulence Factors ◽  
Hemolytic Activity ◽  
Protein Biosynthesis ◽  
The United States ◽  
Aureus Strain ◽  
Protein Synthesis Inhibitors ◽  
Subinhibitory Concentrations

Abstract Background In animal models of Staphylococcus aureus infection, α-hemolysin has been shown to be a key virulence factor. Treatment of S. aureus with subinhibitory levels of protein synthesis inhibitors can decrease α-hemolysin expression. Omadacycline, a novel aminomethylcycline antibiotic in the tetracycline class of bacterial protein biosynthesis inhibitors, is approved in the United States for treatment of community-acquired bacterial pneumonia (CABP) and acute bacterial skin and skin structure infections (ABSSSI) in adults. This study was performed to determine the durability of inhibition and effect of subinhibitory concentrations of omadacycline on S. aureus hemolytic activity. Methods All experiments used the methicillin-sensitive S. aureus strain Wood 46 (ATCC 10832), a laboratory strain known to secrete high levels of α-hemolysin. Minimum inhibitory concentrations (MICs) of omadacycline and comparator antibiotics (tetracycline, cephalothin, clindamycin, vancomycin, linezolid) were determined. Growth of S. aureus with all antibiotics was determined and the percentage of hemolysis assayed. “Washout” experiments were performed with omadacycline only. Results S. aureus cultures treated with 1/2 or 1/4 the MIC of omadacycline for 4 hours showed hemolysis units/108 CFU of 47% and 59% of vehicle-treated cultures, respectively (Fig. 1A, 1B). In washout experiments, treatment with as little as 1/4 the MIC of omadacycline for 1 hour decreased the hemolysis units/108 CFU by 60% for 4 hours following removal of the drug (Table 1). Figure 1 Table 1 Conclusion Omadacycline inhibited S. aureus hemolytic activity in vitro at subinhibitory concentrations and inhibition was maintained for ≥ 4 hours after removal of extracellular drug (Fig. 2). The suppression of virulence factors throughout the approved omadacycline dosing interval, in addition to the in vitro potency of omadacycline, may contribute to the efficacy of omadacycline for ABSSSI and CABP due to virulent S. aureus. This finding may apply to other organisms and other virulence factors that require new protein synthesis to establish disease. Figure 2 Disclosures Alisa W. Serio, PhD, Paratek Pharmaceuticals, Inc. (Employee, Shareholder) S. Ken Tanaka, PhD, Paratek Pharmaceuticals, Inc. (Employee, Shareholder) Kelly Wright, PharmD, Paratek Pharmaceuticals, Inc. (Employee, Shareholder) Lynne Garrity-Ryan, PhD, Paratek Pharmaceuticals, Inc. (Employee, Shareholder)

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