Mechanism of Action in Model Organisms: Interfacing Chemistry, Genetics and Genomics

The Antimicrobial Mechanism of Action of Epsilon-Poly-l-Lysine

Applied and Environmental Microbiology ◽

10.1128/aem.02204-14 ◽

2014 ◽

Vol 80 (24) ◽

pp. 7758-7770 ◽

Cited By ~ 99

Author(s):

Morten Hyldgaard ◽

Tina Mygind ◽

Brian S. Vad ◽

Marcel Stenvang ◽

Daniel E. Otzen ◽

...

Keyword(s):

Lipid Bilayers ◽

Mechanism Of Action ◽

Cell Morphology ◽

Morphological Changes ◽

Divalent Cations ◽

Membrane Integrity ◽

Model Organisms ◽

Microscopy Imaging ◽

Content Type ◽

E Coli

ABSTRACTEpsilon-poly-l-lysine (ε-PL) is a natural antimicrobial cationic peptide which is generally regarded as safe (GRAS) as a food preservative. Although its antimicrobial activity is well documented, its mechanism of action is only vaguely described. The aim of this study was to clarify ε-PL's mechanism of action usingEscherichia coliandListeria innocuaas model organisms. We examined ε-PL's effect on cell morphology and membrane integrity and used an array ofE. colideletion mutants to study how specific outer membrane components affected the action of ε-PL. We furthermore studied its interaction with lipid bilayers using membrane models.In vitrocell studies indicated that divalent cations and the heptose I and II phosphate groups in the lipopolysaccharide layer ofE. coliare critical for ε-PL's binding efficiency. ε-PL removed the lipopolysaccharide layer and affected cell morphology ofE. coli, whileL. innocuaunderwent minor morphological changes. Propidium iodide staining showed that ε-PL permeabilized the cytoplasmic membrane in both species, indicating the membrane as the site of attack. We compared the interaction with neutral or negatively charged membrane systems and showed that the interaction with ε-PL relied on negative charges on the membrane. Suspended membrane vesicles were disrupted by ε-PL, and a detergent-like disruption ofE. colimembrane was confirmed by atomic force microscopy imaging of supported lipid bilayers. We hypothesize that ε-PL destabilizes membranes in a carpet-like mechanism by interacting with negatively charged phospholipid head groups, which displace divalent cations and enforce a negative curvature folding on membranes that leads to formation of vesicles/micelles.

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Bacteriophages; Major Applications and Phage Therapy

NUST Journal of Natural Sciences ◽

10.53992/njns.v1i1.25 ◽

2021 ◽

Vol 1 (1) ◽

pp. 6-10

Author(s):

Waqas Nasir ◽

Irshad Ul Haq ◽

Saba Safdar ◽

Ishtiaq Qadri

Keyword(s):

Mechanism Of Action ◽

Phage Therapy ◽

Underdeveloped Country ◽

Surface Cleaning ◽

Model Organisms ◽

Conventional Chemotherapy ◽

Proper Understanding ◽

Therapeutic Uses

An introduction to bacteriophages along with the general areas of application is described with special and detailed discussion of therapeutic uses of phages and phage enzymes. Phage therapy being safer and faster than conventional chemotherapy has been employed for a while but its incorporation into general disease combating methods has to make a few pit stops those being the proper understanding of phage behaviour in vivo among others. The experiments done on model organisms and humans are described. Industrial benefits of phages, their surface cleaning abilities as well as use of bacteriophages in livestock and poultry developement are highlighted. Phages as therapeutics hold a promising future due to their novel nature and mechanism of action for an underdeveloped country like ours.

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Multi-Species Phenotypic Screening across Disease Models of Mucolipidosis Type IV

10.1101/2021.03.05.434120 ◽

2021 ◽

Author(s):

Andrea Hadjikyriacou ◽

Sangeetha Iyer ◽

Joshua D. Mast ◽

Nina DiPrimio ◽

John Concannon ◽

...

Keyword(s):

Mechanism Of Action ◽

Transient Receptor Potential ◽

Model Organisms ◽

Disease Models ◽

Cyclin Dependent Kinase ◽

Chemical Probes ◽

Mucolipidosis Type Iv ◽

Type Iv ◽

Invertebrate Model ◽

Mucolipidosis Type

AbstractInvertebrate model organisms (the nematode Caenorhabditis elegans and the fruit fly Drosophila melanogaster) are valuable tools to bridge the gap between traditional in vitro discovery and preclinical animal models. Invertebrate model organisms are poised to serve as better disease models than 2D cellular monocultures for drug discovery, as well as easier and more cost-effective to scale up than 3D organoids/assembloids or co-cultures. A strength of model organisms is the opportunity to probe conserved biology such as lysosomal function and autophagy in a physiological setting. However, invertebrate models are not without pharmacokinetic and pharmacodynamic challenges, such as poor tissue penetration and confidence in a compound’s mechanism of action. To confront those challenges, we took advantage of the Novartis mechanism-of-action box (MoA Box), a compound library of well-annotated and drug-like chemical probes. Curious as to how the MoA Box, comprised of chemical probes optimized for mammalian targets, would fare in an invertebrate setting we screened the MoA Box across three different models of the lysosomal storage disease mucolipidosis Type IV (MLIV). MLIV is caused by mutations in the lysosomal transient receptor potential ion channel mucolipin-1 (TRPML1) resulting in hyper-acidic lysosomes and dysregulated autophagy. The overlap of screening hits from worm, fly, and patient fibroblast screens identified cyclin-dependent kinase (CDK) inhibition as an evolutionarily conserved disease modifier and potential drug repurposing strategy.Summary statementA trio of phenotypic screens across Drosophila, C. elegans, and H. sapiens models of mucolipidosis IV was performed and identified overlapping hits including cyclin-dependent kinase inhibitors.

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Twenty-five years of mTOR: Uncovering the link from nutrients to growth

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1716173114 ◽

2017 ◽

Vol 114 (45) ◽

pp. 11818-11825 ◽

Cited By ~ 160

Author(s):

David M. Sabatini

Keyword(s):

Protein Kinase ◽

Mechanism Of Action ◽

Neurological Disease ◽

Mtor Signaling ◽

Model Organisms ◽

Multiple Model ◽

Rag Gtpases ◽

Mtor Protein ◽

Personal Reflections ◽

Mass Accumulation

In my PNAS Inaugural Article, I describe the development of the mTOR field, starting with efforts to understand the mechanism of action of the drug rapamycin, which ∼25 y ago led to the discovery of the mTOR protein kinase. I focus on insights that we have contributed and on work that has been particularly influential to me, as well as provide some personal reflections and stories. We now appreciate that, as part of two distinct complexes, mTORC1 and mTORC2, mTOR is the major regulator of growth (mass accumulation) in animals and is the key link between the availability of nutrients in the environment and the control of most anabolic and catabolic processes. Nutrients signal to mTORC1 through the lysosome-associated Rag GTPases and their many regulators and associated cytosolic and lysosomal nutrient sensors. mTOR signaling is deregulated in common diseases, like cancer and epilepsy, and mTORC1 is a well-validated modulator of aging in multiple model organisms. There is significant excitement around using mTORC1 inhibitors to treat cancer and neurological disease and, potentially, to improve healthspan and lifespan.

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Reductionist thinking and animal models in neuropsychiatric research

Behavioral and Brain Sciences ◽

10.1017/s0140525x18001231 ◽

2019 ◽

Vol 42 ◽

Cited By ~ 1

Author(s):

Nicole M. Baran

Keyword(s):

Animal Models ◽

Mental Disorders ◽

Environmental Factors ◽

Neuropsychiatric Disorders ◽

Model Organisms ◽

Developmental Genetic ◽

Term Study ◽

Genetic And Environmental Factors ◽

Mechanisms Of Plasticity

AbstractReductionist thinking in neuroscience is manifest in the widespread use of animal models of neuropsychiatric disorders. Broader investigations of diverse behaviors in non-model organisms and longer-term study of the mechanisms of plasticity will yield fundamental insights into the neurobiological, developmental, genetic, and environmental factors contributing to the “massively multifactorial system networks” which go awry in mental disorders.

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Apoptosis and development

Essays in Biochemistry ◽

10.1042/bse0390011 ◽

2003 ◽

Vol 39 ◽

pp. 11-24 ◽

Cited By ~ 6

Author(s):

Justin V McCarthy

Keyword(s):

Drosophila Melanogaster ◽

Mammalian Cells ◽

Cell Number ◽

Model Organisms ◽

Biological Processes ◽

Nematode Caenorhabditis Elegans ◽

Apoptotic Pathway ◽

Genetic Pathways ◽

Evolutionarily Conserved ◽

Multicellular Organisms

Apoptosis is an evolutionarily conserved process used by multicellular organisms to developmentally regulate cell number or to eliminate cells that are potentially detrimental to the organism. The large diversity of regulators of apoptosis in mammalian cells and their numerous interactions complicate the analysis of their individual functions, particularly in development. The remarkable conservation of apoptotic mechanisms across species has allowed the genetic pathways of apoptosis determined in lower species, such as the nematode Caenorhabditis elegans and the fruitfly Drosophila melanogaster, to act as models for understanding the biology of apoptosis in mammalian cells. Though many components of the apoptotic pathway are conserved between species, the use of additional model organisms has revealed several important differences and supports the use of model organisms in deciphering complex biological processes such as apoptosis.

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The glycomes of Caenorhabditis elegans and other model organisms

Biochemical Society Symposium ◽

10.1042/bss0690117 ◽

2002 ◽

Vol 69 ◽

pp. 117-134 ◽

Cited By ~ 47

Author(s):

Stuart M. Haslam ◽

David Gems ◽

Howard R. Morris ◽

Anne Dell

Keyword(s):

Caenorhabditis Elegans ◽

Current Knowledge ◽

Structural Data ◽

Model Organisms ◽

Entire Genome ◽

C Elegans ◽

The Face ◽

Area Of Concern ◽

Nematode Worm

There is no doubt that the immense amount of information that is being generated by the initial sequencing and secondary interrogation of various genomes will change the face of glycobiological research. However, a major area of concern is that detailed structural knowledge of the ultimate products of genes that are identified as being involved in glycoconjugate biosynthesis is still limited. This is illustrated clearly by the nematode worm Caenorhabditis elegans, which was the first multicellular organism to have its entire genome sequenced. To date, only limited structural data on the glycosylated molecules of this organism have been reported. Our laboratory is addressing this problem by performing detailed MS structural characterization of the N-linked glycans of C. elegans; high-mannose structures dominate, with only minor amounts of complex-type structures. Novel, highly fucosylated truncated structures are also present which are difucosylated on the proximal N-acetylglucosamine of the chitobiose core as well as containing unusual Fucα1–2Gal1–2Man as peripheral structures. The implications of these results in terms of the identification of ligands for genomically predicted lectins and potential glycosyltransferases are discussed in this chapter. Current knowledge on the glycomes of other model organisms such as Dictyostelium discoideum, Saccharomyces cerevisiae and Drosophila melanogaster is also discussed briefly.

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