5. Uncontrolled Cell Division and Migration of Q neuroblasts in mutant strains of C. elegans

2018 ◽  
Author(s):  
Brandon Lam
Keyword(s):  
Cell Division ◽  
Cell Metabolism ◽  
Model Organism ◽  
C Elegans ◽  
Mutant Strains ◽  
Increase Risk ◽  
And Migration ◽  
Nematode Worm

Cancer is one of the most prevalent and deadly diseases in today's society, affecting millions of people around the globe. Uncontrolled cell division and migration which are two of the six major hallmarks of cancer have been studied extensively in vitro, however in vivo these hallmarks are not well understood. We used the Caenorhabditis elegans nematode worm as our model organism in order to study these two hallmarks. In unfavorable environmental conditions such as starvation, C. elegans can enter a developmental arrest in where certain cell metabolism ceases to continue, this stage is known as L1 arrest. Normally in L1 arrested worms, there are 2 distinct Q neuroblast cells which are precursors of sensory and interneurons that do not divide and migrate. However, when we mutate certain genes, we noticed that the two Q neuroblasts inappropriately divided and migrated, this suggests that we have identified a good model to study uncontrolled cell division and migration. We have already found one gene that when mutated, results in the Q neuroblasts inappropriately dividing and migrating at L1 arrest, now we are looking for other mutated genes that can cause this phenotype, this ultimately allows us to identify new mechanisms that cause an increase risk in cancer.​

scholarly journals A fast and reliable method for monitoring genomic instability in the model organism Caenorhabditis elegans

2021 ◽  
Author(s):  
Merle Marie Nicolai ◽  
Barbara Witt ◽  
Andrea Hartwig ◽  
Tanja Schwerdtle ◽  
Julia Bornhorst
Keyword(s):  
Caenorhabditis Elegans ◽  
Animal Experiments ◽  
Model Organism ◽  
Animal Testing ◽  
C Elegans ◽  
Testing Strategies ◽  
Genotoxic Agents ◽  
Genotoxicity Testing

AbstractThe identification of genotoxic agents and their potential for genotoxic alterations in an organism is crucial for risk assessment and approval procedures of the chemical and pharmaceutical industry. Classically, testing strategies for DNA or chromosomal damage focus on in vitro and in vivo (mainly rodent) investigations. In cell culture systems, the alkaline unwinding (AU) assay is one of the well-established methods for detecting the percentage of double-stranded DNA (dsDNA). By establishing a reliable lysis protocol, and further optimization of the AU assay for the model organism Caenorhabditis elegans (C. elegans), we provided a new tool for genotoxicity testing in the niche between in vitro and rodent experiments. The method is intended to complement existing testing strategies by a multicellular organism, which allows higher predictability of genotoxic potential compared to in vitro cell line or bacterial investigations, before utilizing in vivo (rodent) investigations. This also allows working within the 3R concept (reduction, refinement, and replacement of animal experiments), by reducing and possibly replacing animal testing. Validation with known genotoxic agents (bleomycin (BLM) and tert-butyl hydroperoxide (tBOOH)) proved the method to be meaningful, reproducible, and feasible for high-throughput genotoxicity testing, and especially preliminary screening.

scholarly journals Detecting changes in the Caenorhabditis elegans intestinal environment using an engineered bacterial biosensor

2019 ◽  
Author(s):  
Jack W. Rutter ◽  
Tanel Ozdemir ◽  
Leonor M. Quintaneiro ◽  
Geraint Thomas ◽  
Filipe Cabreiro ◽  
...  
Keyword(s):  
Caenorhabditis Elegans ◽  
Rational Design ◽  
Model Organism ◽  
Bacterial Biosensor ◽  
Intestinal Environment ◽  
C Elegans ◽  
Ideal Candidate ◽  
Diagnostic Applications

AbstractCaenorhabditis elegans has become a key model organism within biology. In particular, the transparent gut, rapid growing time and ability to create a defined gut microbiota make it an ideal candidate organism for understanding and engineering the host microbiota. Here we present the development of an experimental model which can be used to characterise whole-cell bacterial biosensors in vivo. A dual-plasmid sensor system responding to isopropyl β-D-1-thiogalactopyranoside was developed and fully characterised in vitro. Subsequently, we show the sensor was capable of detecting and reporting on changes in the intestinal environment of C. elegans after introducing exogenous inducer into the environment. The protocols presented here may be used for aiding the rational design of engineered bacterial circuits, primarily for diagnostic applications. In addition, the model system may serve to reduce the use of current animal models and aid in the exploration of complex questions within general nematode and host-microbe biology.

Caenorhabditis elegans: A promising contrivance to study neurotoxicity and oxidative stress

2021 ◽  
Vol 16 (10) ◽  
pp. 198-206
Author(s):  
Kiran Singh ◽  
Shweta Yadav
Keyword(s):  
Oxidative Stress ◽  
Caenorhabditis Elegans ◽  
Genetic Manipulation ◽  
Model Organism ◽  
Mechanisms Of Toxicity ◽  
C Elegans ◽  
Toxicological Studies ◽  
And Oxidative Stress

Owing to ubiquitous distribution, high abundances and ecological relevance, Caenorhabditis elegans has strong potential interest as barometer of environment and human health. Ecotoxicological methods are used to evaluate the effect of various anthropogenic contaminants on the ecosystems that circumscribe both in-vivo and in-vitro toxicities to explore the pathways and mechanisms of toxicity and to set precise toxicity thresholds. The interest in C. elegans, as a model organism in toxicological studies, has increased over the past few decades. The enticement of C. elegans comes from the ease of metabolically active digestive, sensory, endocrine, neuromuscular, reproductive systems and genetic manipulation along with the ability to fluorescently label neuronal subtypes. The study reviews the competence of Caenorhabditis elegans as a potential model organism in various toxicity assays specifically neurotoxicity and oxidative stress.

scholarly journals Comparative phytochemical analysis of Phlogacanthus thyrsiflorus Nees: Implications on attenuation of pro-oxidants and pathogen virulence in Caenorhabditis elegans model system

2017 ◽  
Vol 10 (5) ◽  
pp. 361
Author(s):  
Kitlangki Suchiang ◽  
Nitasha H Kayde
Keyword(s):  
Oxidative Stress ◽  
Free Radicals ◽  
Free Radical ◽  
Caenorhabditis Elegans ◽  
Model System ◽  
Wild Type ◽  
C Elegans ◽  
Mutant Strains

Background: Phlogacanthus thyrsiflorus Nees (P. thyrsiflorus) of Acanthaceae family is endogenous to sub-tropical Himalayas. It has been reported to be used traditionally in Jaintia tribe of Meghalaya, India for treatment of many ailments.Objectives: The aim was to detect the active compounds present in the leaves for evaluation of in vitro free radicals scavenging potentials. Leaves protective actions in vivo will be investigated using Caenorhabditis elegans (C. elegans) model system utilizing wild type and mutant strains and the phenomena of host-pathogens interactions.Materials and methods: Gas chromatography/ Mass spectrometry (GC/MS) was used for detection of different compounds present. The versatility of leaf extracts to scavenge different free radicals generated in vitro was assessed with different in vitro methods. Survival analysis of wild type and mutant strains C. elegans under enhanced pro-oxidants exposure was investigated in vivo. Fast killing assay was also performed to study the extracts modulatory activity on host C. elegans survival under pathogen Pseudomonas aeruginosa infection.Results:  Forty compounds were detected in methanolic fraction of the extract with variable percentages. Both aqueous and methanol extract possessed remarkable, versatile free radical scavenging activity irrespective of the types of free radical generated. The in vivo experiments are in compliance, with observable increased survival ability percentage of C. elegans under intense exogenous oxidative stress and pathogen infection.Conclusion: Our findings enlightened the different compounds present with versatility of P. thyrsiflorus in tackling different free radicals generated both in vitro and in vivo that highly support for its candidature as a good antioxidant source. Our findings may justify the historical relevance of this plant in herbal remedies that could form the basis for inquiry of new active principles.Keywords: Free radicals, Oxidative stress, Caenorhabditis elegans, Phlogacanthus thyrsiflorus, Phytochemicals

scholarly journals Identification, functional expression and enzymic analysis of two distinct CaaX proteases from Caenorhabditis elegans

2003 ◽  
Vol 370 (3) ◽  
pp. 1047-1054 ◽  
Author(s):  
Juan CADIÑANOS ◽  
Walter K. SCHMIDT ◽  
Antonio FUEYO ◽  
Ignacio VARELA ◽  
Carlos LÓPEZ-OTÍN ◽  
...  
Keyword(s):  
Caenorhabditis Elegans ◽  
Model Organism ◽  
Functional Expression ◽  
Cysteine Residue ◽  
C Elegans ◽  
Ras Gtpases ◽  
Acid Protein ◽  
Bona Fide

Post-translational processing of proteins such as the Ras GTPases, which contain a C-terminal CaaX motif (where C stands for cysteine, a for aliphatic and X is one of several amino acids), includes prenylation, proteolytic removal of the C-terminal tripeptide and carboxy-methylation of the isoprenyl-cysteine residue. In the present study, we report the presence of two distinct CaaX-proteolytic activities in membrane extracts from Caenorhabditis elegans, which are sensitive to EDTA and Tos-Phe-CH2Cl (tosylphenylalanylchloromethane; ‘TPCK') respectively. A protein similar to the mammalian and yeast farnesylated-proteins converting enzyme-1 (FACE-1)/Ste24p CaaX metalloprotease, encoded by a hypothetical gene (CeFACE-1/C04F12.10) found in C. elegans chromosome I, probably accounts for the EDTA-sensitive activity. An orthologue of FACE-2/Rce1p, the enzyme responsible for the proteolytic maturation of Ras oncoproteins and other prenylated substrates, probably accounts for the Tos-Phe-CH2Cl-sensitive activity, even though the gene for FACE-2/Rce1 has not been previously identified in this model organism. We have identified a previously overlooked gene in C. elegans chromosome V, which codes for a 266-amino-acid protein (CeFACE-2) with 30% sequence identity to human FACE-2/Rce1. We show that both CeFACE-1 and CeFACE-2 have the ability to promote production of the farnesylated yeast pheromone a-factor in vivo and to cleave a farnesylated peptide in vitro. These results indicate that CeFACE-1 and CeFACE-2 are bona fide CaaX proteases and support the evolutionary conservation of this proteolytic system in eukaryotes.

scholarly journals Molecular basis for PICS-mediated piRNA biogenesis and cell division

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Xiaoyang Wang ◽  
Chenming Zeng ◽  
Shanhui Liao ◽  
Zhongliang Zhu ◽  
Jiahai Zhang ◽  
...  
Keyword(s):  
Cell Division ◽  
Chromosome Segregation ◽  
Cell Biology ◽  
Interaction Network ◽  
C Elegans ◽  
Biochemical Experiment ◽  
In Vitro Interaction ◽  
Structural Insights

AbstractBy incorporating two mutually exclusive factors, PID-1 and TOST-1, C. elegans PICS complex plays important roles in piRNA biogenesis, chromosome segregation and cell division. We firstly map the interaction network between PICS subunits, then uncover the mechanisms underlying the interactions between PICS subunits by solving several complex structures, including those of TOFU-6/PICS-1, ERH-2/PICS-1, and ERH-2/TOST-1. Our biochemical experiment also demonstrates that PICS exists as an octamer consisting of two copies of each subunit. Combining structural analyses with mutagenesis experiments, we identify interfacial residues of PICS subunits that are critical for maintaining intact PICS complex in vitro. Furthermore, using genetics, cell biology and imaging experiments, we find that those mutants impairing the in vitro interaction network within PICS, also lead to dysfunction of PICS in vivo, including mislocalization of PICS, and reduced levels of piRNAs or aberrant chromosome segregation and cell division. Therefore, our work provides structural insights into understanding the PICS-mediated piRNA biogenesis and cell division.

scholarly journals Biotin Transport-Targeting Polysaccharide-Modified PAMAM G3 Dendrimer as System Delivering α-Mangostin into Cancer Cells and C. elegans Worms

2021 ◽  
Vol 22 (23) ◽  
pp. 12925
Author(s):  
Joanna Markowicz ◽  
Łukasz Uram ◽  
Stanisław Wołowiec ◽  
Wojciech Rode
Keyword(s):  
Cancer Cells ◽  
Delivery System ◽  
Water Solubility ◽  
Model Organism ◽  
Amide Bond ◽  
C Elegans ◽  
Wide Range ◽  
Amine Groups

The natural xanthone α-mangostin (αM) exhibits a wide range of pharmacological activities, including antineoplastic and anti-nematode properties, but low water solubility and poor selectivity of the drug prevent its potential clinical use. Therefore, the targeted third-generation poly(amidoamine) dendrimer (PAMAM G3) delivery system was proposed, based on hyperbranched polymer showing good solubility, high biocompatibility and low immunogenicity. A multifunctional nanocarrier was prepared by attaching αM to the surface amine groups of dendrimer via amide bond in the ratio 5 (G32B12gh5M) or 17 (G32B10gh17M) residues per one dendrimer molecule. Twelve or ten remaining amine groups were modified by conjugation with D-glucoheptono-1,4-lactone (gh) to block the amine groups, and two biotin (B) residues as targeting moieties. The biological activity of the obtained conjugates was studied in vitro on glioma U-118 MG and squamous cell carcinoma SCC-15 cancer cells compared to normal fibroblasts (BJ), and in vivo on a model organism Caenorhabditis elegans. Dendrimer vehicle G32B12gh at concentrations up to 20 µM showed no anti-proliferative effect against tested cell lines, with a feeble cytotoxicity of the highest concentration seen only with SCC-15 cells. The attachment of αM to the vehicle significantly increased cytotoxic effect of the drug, even by 4- and 25-fold for G32B12gh5M and G32B10gh17M, respectively. A stronger inhibition of cells viability and influence on other metabolic parameters (proliferation, adhesion, ATP level and Caspase-3/7 activity) was observed for G32B10gh17M than for G32B12gh5M. Both bioconjugates were internalized efficiently into the cells. Similarly, the attachment of αM to the dendrimer vehicle increased its toxicity for C. elegans. Thus, the proposed α-mangostin delivery system allowed the drug to be more effective in the dendrimer-bound as compared to free state against both cultured the cancer cells and model organism, suggesting that this treatment is promising for anticancer as well as anti-nematode chemotherapy.

scholarly journals Molecular basis for PICS-mediated piRNA biogenesis and cell division

2021 ◽  
Author(s):  
Xiaoyang Wang ◽  
Chenming Zeng ◽  
Shanhui Liao ◽  
Zhongliang Zhu ◽  
Jiahai Zhang ◽  
...  
Keyword(s):  
Cell Division ◽  
Chromosome Segregation ◽  
Cell Biology ◽  
Interaction Network ◽  
C Elegans ◽  
Biochemical Experiment ◽  
In Vitro Interaction ◽  
Structural Insights

By incorporating two mutually exclusive factors, PID-1 and TOST-1, C. elegans PICS complex plays important roles in piRNA biogenesis, chromosome segregation and cell division, respectively. We firstly mapped the interaction network between PICS subunits. By solving the several complex structures, including those of TOFU-6/PICS-1, ERH-2/PICS-1, and ERH-2/TOST-1, we uncover the mechanisms underlying the interactions between PICS subunits. Our biochemical experiment demonstrates that PICS exists as an octamer consisting of two copies of each subunits. Combining structural analyses with mutagenesis experiments, we identified residues of PICS subunits that are critical for maintaining intact PICS complex in vitro. Furthermore, using genetics, cell biology and imaging experiments, we found that those mutants impairing the in vitro interaction network within PICS, also lead to abnormal dysfunction PICS in vivo, including mislocalization of PICS, and reduced levels of piRNAs or abnormal chromosome segregation and cell division. Therefore, our work provides structural insights into understanding the PICS-mediated piRNA biogenesis and cell division.

scholarly journals Promoters of the dhs-21 gene encoding dicarbonyl/l-xylulose reductase in Caenorhabditis elegans

2018 ◽  
Vol 15 (2) ◽  
pp. 359-365
Author(s):  
Lê Thọ Sơn ◽  
Joohong Ahnn ◽  
Jeong Hoon Cho ◽  
Nguyễn Huy Hoàng
Keyword(s):  
Caenorhabditis Elegans ◽  
Model Organism ◽  
Biological Research ◽  
Loss Of Function ◽  
Wild Type ◽  
C Elegans ◽  
Larval Stages ◽  
Vital Functions

Dicarbonyl/L-xylulose (DCXR) was identified as a dehydrogenase. This type of enzyme was presented in various forms of lives including bacteria, fungi, plants and animals. Generally, it converts L-xylulose to xylitol in the presence of either cofactor NADH or NADPH in vitro. Previous studies reported the biochemistry properties and crystal structure but largely uncovered biological roles of DCXRs. It was impossible to dissect the functions in mice or human cells that had many DCXR homologs in their genomes. Interestingly, the wild-type Caenorhabditis elegans, a well-known model organism in biological research, has only nuclear genomic dhs-21 that encodes a unique homologous DCXR. Thus Ce.dhs-21 and the host C. elegans were relevant for investigation of the physiologically-vital functions of the DCXR. This research aimed to the expression of dhs-21 in vivo. We defined three promoters , manipulated three relative reporter-constructs that conjugated the dhs-21 gene and Green Flouresent Protein (known as GFP) one. The construct vectors were transferred into wild-type C. elegans N2 and as well as the hermaphroditic loss of function dhs-21(jh129) by microinjection. In the results, we found that the expression pattern of dhs-21 under the only p2-promoter construct was stable and similar to immunogold Electric Microscopy (EM) images. The dhs-21 gene was expressed in both sexes of at all larval stages till the deaths of worms. DHS-21 was expressed in the cytosol of the intestinal, gonad sheath and uterous seam cell (utse).

Targeting Matrix Metalloproteinases in Atherosclerosis and Cardiovascular Dysfunction

2019 ◽  
Vol 70 (2) ◽  
pp. 718-720
Author(s):  
Lucia Corina Dima-Cozma ◽  
Sebastian Cozma ◽  
Delia Hinganu ◽  
Cristina Mihaela Ghiciuc ◽  
Florin Mitu
Keyword(s):  
Smooth Muscle ◽  
Matrix Metalloproteinases ◽  
Cholesterol Synthesis ◽  
Balloon Dilation ◽  
Aortic Aneurysms ◽  
Arterial Lesions ◽  
Smooth Muscle Cell Migration ◽  
And Migration

Matrix metalloproteinases (MMPs) are the primary mediators of extracellular remodeling and their properties are useful in diagnostic evaluation and treatment. They are zinc-dependent proteases. MMPs have been involved in the mechanisms of atherosclerosis in various arterial areas, ischemic heart disease and myocardial infarction, atrial fibrillation and aortic aneurysms. Recently, MMP9 has been implicated in dyslipidemia and cholesterol synthesis by the liver. Increased MMP expression and activity has been associated with neointimal arterial lesions and migration of smooth muscle cells after arterial balloon dilation, while MMP inhibition decreases smooth muscle cell migration in vivo and in vitro.

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