scholarly journals Molecular mechanisms of an antimicrobial peptide piscidin (Lc-pis) in a parasitic protozoan, Cryptocaryon irritans

BMC Genomics ◽  
2018 ◽  
Vol 19 (1) ◽  
Author(s):  
Ruanni Chen ◽  
Yong Mao ◽  
Jun Wang ◽  
Min Liu ◽  
Ying Qiao ◽  
...  
Keyword(s):  
Antimicrobial Peptide ◽  
Molecular Mechanisms ◽  
Parasitic Protozoan ◽  
Cryptocaryon Irritans

scholarly journals Antimicrobial Peptide TP4 Targets Mitochondrial Adenine Nucleotide Translocator 2

Marine Drugs ◽  
2020 ◽  
Vol 18 (8) ◽  
pp. 417
Author(s):  
Bor-Chyuan Su ◽  
Yi-Chung Liu ◽  
Chen-Hung Ting ◽  
Ping-Chiang Lyu ◽  
Jyh-Yih Chen
Keyword(s):  
Antimicrobial Peptide ◽  
Molecular Mechanisms ◽  
Adenine Nucleotide ◽  
Docking Studies ◽  
Adenine Nucleotide Translocator ◽  
Nucleotide Exchange ◽  
Nile Tilapia Oreochromis Niloticus ◽  
Key Residues

Tilapia piscidin (TP) 4 is an antimicrobial peptide derived from Nile tilapia (Oreochromis niloticus), which shows broad-spectrum antibacterial activity and excellent cancer-killing ability in vitro and in vivo. Like many other antimicrobial peptides, TP4 treatment causes mitochondrial toxicity in cancer cells. However, the molecular mechanisms underlying TP4 targeting of mitochondria remain unclear. In this study, we used a pull-down assay on A549 cell lysates combined with LC-MS/MS to discover that TP4 targets adenine nucleotide translocator (ANT) 2, a protein essential for adenine nucleotide exchange across the inner membrane. We further showed that TP4 accumulates in mitochondria and colocalizes with ANT2. Moreover, molecular docking studies showed that the interaction requires Phe1, Ile2, His3, His4, Ser11, Lys14, His17, Arg21, Arg24 and Arg25 residues in TP4 and key residues within the cavity of ANT2. These findings suggest a mechanism by which TP4 may induce mitochondrial dysfunction to disrupt cellular energy metabolism.

scholarly journals A Mig-14-like protein (PA5003) affects antimicrobial peptide recognition in Pseudomonas aeruginosa

Microbiology ◽  
2011 ◽  
Vol 157 (9) ◽  
pp. 2647-2657 ◽  
Author(s):  
Nicholas Jochumsen ◽  
Yang Liu ◽  
Søren Molin ◽  
Anders Folkesson
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Antimicrobial Peptides ◽  
Antimicrobial Peptide ◽  
Pathogenic Bacteria ◽  
Molecular Mechanisms ◽  
Fluorescent Protein ◽  
Flow Chamber ◽  
Gene Encoding ◽  
Conventional Antibiotics ◽  
Green Fluorescent

The evolution of antibiotic resistance in pathogenic bacteria is a growing global health problem which is gradually making the treatment of infectious diseases less efficient. Antimicrobial peptides are small charged molecules found in organisms from the complete phylogenetic spectrum. The peptides are attractive candidates for novel drug development due to their activity against bacteria that are resistant to conventional antibiotics, and reports of peptide resistance are rare in the clinical setting. Paradoxically, many clinically relevant bacteria have mechanisms that can recognize and respond to the presence of cationic antimicrobial peptides (CAMPs) in the environment by changing the properties of the microbial surface thereby increasing the tolerance of the microbes towards the peptides. In Pseudomonas aeruginosa an essential component of this inducible tolerance mechanism is the lipopolysaccharide modification operon arnBCADTEF–PA3559 which encodes enzymes required for LPS alterations leading to increased antimicrobial peptide tolerance. The expression of the operon is induced by the presence of CAMPs in the environment but the molecular mechanisms underlying the cellular recognition of the peptides are poorly elucidated. In this work, we investigate the factors influencing arnB expression by transposon mutagenesis and arnB promoter green fluorescent protein reporters. We have identified a novel gene encoding a Mig-14-like protein that is required for recognition of the CAMPs colistin and Novispirin G10 by P. aeruginosa. Moreover, we show that this gene is also required for the formation of CAMP-tolerant subpopulations in P. aeruginosa hydrodynamic flow chamber biofilms.

scholarly journals The Antimicrobial Peptide Gramicidin S Enhances Membrane Adsorption and Ion Pore Formation Potency of Chemotherapy Drugs in Lipid Bilayers

Membranes ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 247
Author(s):  
Md. Ashrafuzzaman
Keyword(s):  
Antimicrobial Peptide ◽  
Lipid Bilayer ◽  
Lipid Bilayers ◽  
Aqueous Phase ◽  
Pore Formation ◽  
Molecular Mechanisms ◽  
Important Conclusion ◽  
Liposome Membrane ◽  
Chemotherapy Drugs ◽  
Gramicidin S

We recently published two novel findings where we found the chemotherapy drugs (CDs) thiocolchicoside (TCC) and taxol to induce toroidal type ion pores and the antimicrobial peptide gramicidin S (GS) to induce transient defects in model membranes. Both CD pores and GS defects were induced under the influence of an applied transmembrane potential (≈100 mV), which was inspected using the electrophysiology record of membrane currents (ERMCs). In this article, I address the regulation of the membrane adsorption and pore formation of CDs due to GS-induced possible alterations of lipid bilayer physical properties. In ERMCs, low micromolar (≥1 μM) GS concentrations in the aqueous phase were found to cause an induction of defects in lipid bilayers, but nanomolar (nM) concentration GS did nothing. For the binary presence of CDs and GS in the membrane-bathing aqueous phase, the TCC pore formation potency is found to increase considerably due to nM concentration GS in buffer. This novel result resembles our recently reported finding that due to the binary aqueous presence of two AMPs (gramicidin A or alamethicin and GS), the pore or defect-forming potency of either AMP increases considerably. To reveal the underlying molecular mechanisms, the influence of GS (0–400 nM) on the quantitative liposome (membrane) adsorption of CD molecules, colchicine and TCC, was tested. I used the recently patented direct detection method, which helps detect the membrane active agents directly at the membrane in the mole fraction relative to its concentrations in aqueous phase. We find that GS, at concentrations known to do nothing to the lipid bilayer electrical barrier properties in ERMCs, increases the membrane adsorption (membrane uptake) of CDs considerably. This phenomenological finding along with the GS effects on CD-induced membrane conductance increase helps predict an important conclusion. The binary presence of AMPs alongside CDs in the lipid membrane vicinity may work toward enhancing the physical adsorption and pore formation potency of CDs in lipid bilayers. This may help understand why CDs cause considerable cytotoxicity.

scholarly journals Identification of Antimicrobial Peptide Genes in Black Rockfish Sebastes schlegelii and Their Responsive Mechanisms to Edwardsiella tarda Infection

Biology ◽  
2021 ◽  
Vol 10 (10) ◽  
pp. 1015
Author(s):  
Min Zhang ◽  
Min Cao ◽  
Yunji Xiu ◽  
Qiang Fu ◽  
Ning Yang ◽  
...  
Keyword(s):  
Antimicrobial Peptide ◽  
Single Molecule ◽  
Molecular Mechanisms ◽  
Expression Patterns ◽  
Amino Acid Sequences ◽  
Edwardsiella Tarda ◽  
Economic Losses ◽  
Dominant Type ◽  
Black Rockfish ◽  
Sebastes Schlegelii

The black rockfish, Sebastes schlegelii, is a typical viviparous teleost, which belongs to the family Scorpaenidae. Due to its high economic and ecological values, S. schlegelii has been widely cultured in East Asian countries. With the enlargement of cultivation scale, bacterial and viral diseases have become the main threats to the farming industry of S. schlegelii, which have resulted in significant economic losses. In this study, Illumina shotgun sequencing, single-molecule real-time (SMRT) sequencing, 10x genomics and high-throughput chromosome conformation capture (Hi-C) technologies were collectively applied to assemble the genome of S. schlegelii. Then, we identified the antimicrobial peptide genes (AMPs) in the S. schlegelii genome. In total, 214 AMPs were identified in the S. schlegelii genome, which can be divided into 33 classes according to the annotation and cataloging of the Antimicrobial Peptides Database (APD3). Among these AMPs, thrombin-derived C-terminal peptide (TCP) was the dominant type, followed by RegIIIgamma and chemokine. The amino acid sequences of the TCP, cgUbiquitin, RegIIIalpha, RegIIIgamma, chemokine shared 32.55%, 42.63%, 29.87%, 28.09%, and 32.15% similarities among the same type in S. schlegelii. Meanwhile, the expression patterns of these AMPs in nine healthy tissues and at different infection time points in intestine were investigated. The results showed that the numbers and types of AMPs that responded to Edwardsiella tarda infection gradually increased as the infection progressed. In addition, we analyzed the phylogenetic relationships of hepcidins in teleost. The identification of AMPs based on the whole genome could provide a comprehensive database of potential AMPs, and benefit for the understanding of the molecular mechanisms of immune responses to E. tarda infection in S. schlegelii. This would further offer insights into an accurate and effective design and development of AMP for aquaculture therapy in the future.

scholarly journals The major surface-metalloprotease of the parasitic protozoan, Leishmania, protects against antimicrobial peptide-induced apoptotic killing

2006 ◽  
Vol 62 (5) ◽  
pp. 1484-1497 ◽  
Author(s):  
Manjusha M. Kulkarni ◽  
W. Robert McMaster ◽  
Elzbieta Kamysz ◽  
Wojciech Kamysz ◽  
David M. Engman ◽  
...  
Keyword(s):  
Antimicrobial Peptide ◽  
Parasitic Protozoan ◽  
Major Surface

Transcription factor/DNA interactions visualized by electron spectroscopic imaging

1992 ◽  
Vol 50 (1) ◽  
pp. 450-451
Author(s):  
David P. Bazett-Jones ◽  
Mark L. Brown
Keyword(s):  
Transcription Factor ◽  
Dna Sequences ◽  
Transcription Initiation ◽  
Molecular Mechanisms ◽  
Phosphorus Content ◽  
Spectroscopic Imaging ◽  
Electron Spectroscopic Imaging ◽  
Dna Backbone ◽  
Two Parameters ◽  
High Level

A multisubunit RNA polymerase enzyme is ultimately responsible for transcription initiation and elongation of RNA, but recognition of the proper start site by the enzyme is regulated by general, temporal and gene-specific trans-factors interacting at promoter and enhancer DNA sequences. To understand the molecular mechanisms which precisely regulate the transcription initiation event, it is crucial to elucidate the structure of the transcription factor/DNA complexes involved. Electron spectroscopic imaging (ESI) provides the opportunity to visualize individual DNA molecules. Enhancement of DNA contrast with ESI is accomplished by imaging with electrons that have interacted with inner shell electrons of phosphorus in the DNA backbone. Phosphorus detection at this intermediately high level of resolution (≈lnm) permits selective imaging of the DNA, to determine whether the protein factors compact, bend or wrap the DNA. Simultaneously, mass analysis and phosphorus content can be measured quantitatively, using adjacent DNA or tobacco mosaic virus (TMV) as mass and phosphorus standards. These two parameters provide stoichiometric information relating the ratios of protein:DNA content.

Dissection of the molecular mechanisms of protein targeting to the peroxisome using immunofluorescence and immunocryoelectron microscopies

1990 ◽  
Vol 48 (3) ◽  
pp. 44-45
Author(s):  
G-A. Keller ◽  
S. J. Gould ◽  
S. Subramani ◽  
S. Krisans
Keyword(s):  
Mammalian Cells ◽  
Molecular Mechanisms ◽  
Protein Targeting ◽  
Firefly Luciferase ◽  
Peroxisomal Enzyme ◽  
Transfected Cells ◽  
Peroxisomal Targeting ◽  
Targeting Signal ◽  
Series Of Experiments ◽  
Peroxisomal Targeting Signal

Subcellular compartments within eukaryotic cells must each be supplied with unique sets of proteins that must be directed to, and translocated across one or more membranes of the target organelles. This transport is mediated by cis- acting targeting signals present within the imported proteins. The following is a chronological account of a series of experiments designed and carried out in an effort to understand how proteins are targeted to the peroxisomal compartment.-We demonstrated by immunocryoelectron microscopy that the enzyme luciferase is a peroxisomal enzyme in the firefly lantern. -We expressed the cDNA encoding firefly luciferase in mammalian cells and demonstrated by immunofluorescence that the enzyme was transported into the peroxisomes of the transfected cells. -Using deletions, linker insertions, and gene fusion to identify regions of luciferase involved in its transport to the peroxisomes, we demonstrated that luciferase contains a peroxisomal targeting signal (PTS) within its COOH-terminal twelve amino acid.

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