scholarly journals Polo kinase phosphorylation determines C. elegans centrosome size and density by biasing SPD-5 toward an assembly-competent conformation

2016 ◽  
Author(s):  
Oliver Wueseke ◽  
David Zwicker ◽  
Anne Schwager ◽  
Yao Liang Wong ◽  
Karen Oegema ◽  
...  
Keyword(s):  
Theoretical Model ◽  
Wild Type ◽  
C Elegans ◽  
Polo Kinase ◽  
Supramolecular Scaffolds ◽  
Long Time ◽  
Pericentriolar Material ◽  
Kinase Phosphorylation

ABSTRACTCentrosomes are major microtubule-organizing centers composed of centrioles surrounded by an extensive proteinacious layer called the pericentriolar material (PCM). In C. elegans embryos, the mitotic PCM expands by Polo-kinase (PLK-1) phosphorylation-accelerated assembly of SPD-5 molecules into supramolecular scaffolds. However, how PLK-1 phosphorylation regulates SPD-5 assembly is not known. We found that a mutant version of SPD-5 that is insensitive to PLK-1 phosphorylation (SPD-54A) could localize to PCM but was unable to rescue the reduction in PCM size and density when wild-type SPD-5 levels were decreased. In vitro, purified SPD-54A self-assembled into functional supramolecular scaffolds over long time scales, suggesting that phosphorylation only controls the rate of SPD-5 scaffold assembly. Furthermore, the SPD-5 scaffold, once assembled, remained intact and supported microtubule nucleation in the absence of PLK-1 activity in vivo. We conclude that Polo Kinase is required for rapid assembly of the PCM scaffold but not for scaffold maintenance or function. Based on this idea, we developed a theoretical model that adequately predicted PCM growth rates in different mutant conditions in vivo. We propose that PLK-1 phosphorylation-dependent conversion of SPD-5 into an assembly-competent form underlies PCM formation in vivo and that the rate of this conversion determines final PCM size and density.

scholarly journals The double-stranded DNA-binding proteins TEBP-1 and TEBP-2 form a telomeric complex with POT-1

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Sabrina Dietz ◽  
Miguel Vasconcelos Almeida ◽  
Emily Nischwitz ◽  
Jan Schreier ◽  
Nikenza Viceconte ◽  
...  
Keyword(s):  
Quantitative Proteomics ◽  
Wild Type ◽  
C Elegans ◽  
Double Stranded Dna ◽  
Telomere Sequence ◽  
Proteomics Approach ◽  
Telomeric Protein ◽  
Regulate Telomere Length

AbstractTelomeres are bound by dedicated proteins, which protect them from DNA damage and regulate telomere length homeostasis. In the nematode Caenorhabditis elegans, a comprehensive understanding of the proteins interacting with the telomere sequence is lacking. Here, we harnessed a quantitative proteomics approach to identify TEBP-1 and TEBP-2, two paralogs expressed in the germline and embryogenesis that associate to telomeres in vitro and in vivo. tebp-1 and tebp-2 mutants display strikingly distinct phenotypes: tebp-1 mutants have longer telomeres than wild-type animals, while tebp-2 mutants display shorter telomeres and a Mortal Germline. Notably, tebp-1;tebp-2 double mutant animals have synthetic sterility, with germlines showing signs of severe mitotic and meiotic arrest. Furthermore, we show that POT-1 forms a telomeric complex with TEBP-1 and TEBP-2, which bridges TEBP-1/-2 with POT-2/MRT-1. These results provide insights into the composition and organization of a telomeric protein complex in C. elegans.

scholarly journals The double-stranded DNA-binding proteins TEBP-1 and TEBP-2 form a telomeric complex with POT-1

2020 ◽  
Author(s):  
Sabrina Dietz ◽  
Miguel Vasconcelos Almeida ◽  
Emily Nischwitz ◽  
Jan Schreier ◽  
Nikenza Viceconte ◽  
...  
Keyword(s):  
Quantitative Proteomics ◽  
Binding Proteins ◽  
Protein Complexes ◽  
Wild Type ◽  
C Elegans ◽  
Double Stranded Dna ◽  
Telomere Sequence ◽  
Proteomics Approach

AbstractTelomeres are bound by dedicated protein complexes, like shelterin in mammals, which protect telomeres from DNA damage. In the nematode Caenorhabditis elegans, a comprehensive understanding of the proteins interacting with the telomere sequence is lacking. Here, we harnessed a quantitative proteomics approach to screen for proteins binding to C. elegans telomeres, and identified TEBP-1 and TEBP-2, two paralogs that associate to telomeres in vitro and in vivo. TEBP-1 and TEBP-2 are expressed in the germline and during embryogenesis. tebp-1 and tebp-2 mutants display strikingly distinct phenotypes: tebp-1 mutants have longer telomeres than wild-type animals, while tebp-2 mutants display shorter telomeres and a mortal germline, a phenotype characterized by transgenerational germline deterioration. Notably, tebp-1; tebp-2 double mutant animals have synthetic sterility, with germlines showing signs of severe mitotic and meiotic arrest. TEBP-1 and TEBP-2 form a telomeric complex with the known single-stranded telomere-binding proteins POT-1, POT-2, and MRT-1. Furthermore, we find that POT-1 bridges the double- stranded binders TEBP-1 and TEBP-2, with the single-stranded binders POT-2 and MRT-1. These results describe the first telomere-binding complex in C. elegans, with TEBP-1 and TEBP-2, two double-stranded telomere binders required for fertility and that mediate opposite telomere dynamics.

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 Global Proteotoxicity Caused by Human β2 Microglobulin Variants Impairs the Unfolded Protein Response in C. elegans

2021 ◽  
Vol 22 (19) ◽  
pp. 10752
Author(s):  
Sarah C. Good ◽  
Katherine M. Dewison ◽  
Sheena E. Radford ◽  
Patricija van Oosten-Hawle
Keyword(s):  
Er Stress ◽  
Molecular Mechanisms ◽  
Amyloid Fibrils ◽  
Signal Sequence ◽  
Systemic Amyloidosis ◽  
Wild Type ◽  
Β2 Microglobulin ◽  
C Elegans

Aggregation of β2 microglobulin (β2m) into amyloid fibrils is associated with systemic amyloidosis, caused by the deposition of amyloid fibrils containing the wild-type protein and its truncated variant, ΔN6 β2m, in haemo-dialysed patients. A second form of familial systemic amyloidosis caused by the β2m variant, D76N, results in amyloid deposits in the viscera, without renal dysfunction. Although the folding and misfolding mechanisms of β2 microglobulin have been widely studied in vitro and in vivo, we lack a comparable understanding of the molecular mechanisms underlying toxicity in a cellular and organismal environment. Here, we established transgenic C. elegans lines expressing wild-type (WT) human β2m, or the two highly amyloidogenic naturally occurring variants, D76N β2m and ΔN6 β2m, in the C. elegans bodywall muscle. Nematodes expressing the D76N β2m and ΔN6 β2m variants exhibit increased age-dependent and cell nonautonomous proteotoxicity associated with reduced motility, delayed development and shortened lifespan. Both β2m variants cause widespread endogenous protein aggregation contributing to the increased toxicity in aged animals. We show that expression of β2m reduces the capacity of C. elegans to cope with heat and endoplasmic reticulum (ER) stress, correlating with a deficiency to upregulate BiP/hsp-4 transcripts in response to ER stress in young adult animals. Interestingly, protein secretion in all β2m variants is reduced, despite the presence of the natural signal sequence, suggesting a possible link between organismal β2m toxicity and a disrupted ER secretory metabolism.

scholarly journals Competition and Resilience between Founder and Introduced Bacteria in the Caenorhabditis elegans Gut

2011 ◽  
Vol 80 (3) ◽  
pp. 1288-1299 ◽  
Author(s):  
Cynthia Portal-Celhay ◽  
Martin J. Blaser
Keyword(s):  
Caenorhabditis Elegans ◽  
Wild Type ◽  
Content Type ◽  
E Coli ◽  
C Elegans ◽  
Serovar Typhimurium ◽  
Colonization Factors

The microbial communities that reside within the intestinal tract in vertebrates are complex and dynamic. In this report, we establish the utility ofCaenorhabditis elegansas a model system for identifying the factors that contribute to bacterial persistence and for host control of gut luminal populations. We found that for N2 worms grown on mixed lawns of bacteria,Salmonella entericaserovar Typhimurium substantially outcompetedEscherichia coli, even whenE. coliwas initially present at 100-fold-higher concentrations. To address whether innate immunity affects the competition, thedaf-2anddaf-16mutants were studied; their total gut bacterial levels reflect overall capacity for colonization, butSalmonellaoutcompetedE. colito an extent similar to wild-type worms. To address the role of virulence properties,SalmonellaΔspi-1Δspi-2was used to compete withE. coli. The net differential was significantly less than that for wild-typeSalmonella; thus,spi-1 spi-2encodesC. eleganscolonization factors. AnE. colistrain with repeatedin vivopassage had an enhanced ability to compete against anin vitro-passedE. colistrain and againstSalmonella. Our data provide evidence of active competition for colonization niches in theC. elegansgut, as determined by bacterial factors and subject toin vivoselection.

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).

scholarly journals Acute, reproductive, and developmental toxicity of essential oils assessed with alternative in vitro and in vivo systems

2020 ◽  
Author(s):  
Peter Lanzerstorfer ◽  
Georg Sandner ◽  
Johannes Pitsch ◽  
Bianca Mascher ◽  
Tobias Aumiller ◽  
...  
Keyword(s):  
Essential Oils ◽  
Mucous Membrane ◽  
Relative Concentration ◽  
Feed Additives ◽  
Wild Type ◽  
Food Preservatives ◽  
C Elegans ◽  
The Impact

Abstract Essential oils (EOs) have attracted increased interest for different applications such as food preservatives, feed additives and ingredients in cosmetics. Due to their reported variable composition of components, they might be acutely toxic to humans and animals in small amounts. Despite the necessity, rigorous toxicity testing in terms of safety evaluation has not been reported so far, especially using alternatives to animal models. Here, we provide a strategy by use of alternative in vitro (cell cultures) and in vivo (Caenorhabditis elegans, hen’s egg test) approaches for detailed investigation of the impact of commonly used rosemary, citrus and eucalyptus essential oil on acute, developmental and reproductive toxicity as well as on mucous membrane irritation. In general, all EOs under study exhibited a comparable impact on measured parameters, with a slightly increased toxic potential of rosemary oil. In vitro cell culture results indicated a concentration-dependent decrease of cell viability for all EOs, with mean IC50 values ranging from 0.08 to 0.17% [v/v]. Similar results were obtained for the C. elegans model when using a sensitized bus-5 mutant strain, with a mean LC50 value of 0.42% [v/v]. In wild-type nematodes, approximately tenfold higher LC50 values were detected. C. elegans development and reproduction was already significantly inhibited at concentrations of 0.5% (wild-type) and 0.1% (bus-5) [v/v] of EO, respectively. Gene expression analysis revealed a significant upregulation of xenobiotic and oxidative stress genes such as cyp-14a3, gst-4, gpx-6 and sod-3. Furthermore, all three EOs under study showed an increased short-time mucous membrane irritation potential, already at 0.5% [v/v] of EO. Finally, GC–MS analysis was performed to quantitate the relative concentration of the most prominent EO compounds. In conclusion, our results demonstrate that EOs can exhibit severe toxic properties, already at low concentrations. Therefore, a detailed toxicological assessment is highly recommended for each EO and single intended application.

scholarly journals The centrosome is a selective phase that nucleates microtubules by concentrating tubulin

2016 ◽  
Author(s):  
Jeffrey B. Woodruff ◽  
Beatriz Ferreira Gomes ◽  
Per O. Widlund ◽  
Julia Mahamid ◽  
Anthony A. Hyman
Keyword(s):  
Phase Separation ◽  
Effector Proteins ◽  
Nanometer Scale ◽  
C Elegans ◽  
Pericentriolar Material ◽  
Dynamic Assembly ◽  
Membrane Bound ◽  
Spherical Droplets

AbstractCentrosomes are non-membrane-bound compartments that nucleate microtubule arrays. They consist of nanometer-scale centrioles surrounded by a micron-scale, dynamic assembly of protein called the pericentriolar material (PCM). To study how PCM forms a spherical compartment that nucleates microtubules, we reconstituted PCM-dependent microtubule nucleation in vitro using recombinant C.elegans proteins. We found that macromolecular crowding drives phase separation of the key PCM scaffold protein SPD-5 into spherical droplets that morphologically and dynamically resemble in vivo PCM. These SPD-5 droplets recruited the microtubule polymerase ZYG-9 (XMAP215 homologue) and the microtubule-stabilizing protein TPXL-1 (TPX2 homologue). Together, these three proteins concentrated tubulin ~4- fold over background, which was sufficient to reconstitute nucleation of microtubule asters in vitro. Our results suggest that in vivo PCM is a selective phase that organizes microtubule arrays through localized concentration of tubulin by microtubule effector proteins.One Sentence SummaryPhase separation of C. elegans centrosome proteins drive the formation of micron-sized microtubule organizing centers.

The Application of the Cold Atmospheric Plasma-Activated Solutions in Cancer Treatment

2018 ◽  
Vol 18 (6) ◽  
pp. 769-775 ◽  
Author(s):  
Dayun Yan ◽  
Jonathan H. Sherman ◽  
Michael Keidar
Keyword(s):  
Cancer Treatment ◽  
Atmospheric Plasma ◽  
Current Status ◽  
Cold Atmospheric Plasma ◽  
Anti Cancer ◽  
Long Time ◽  
Key Topics ◽  
The Common

Background: Over the past five years, the cold atmospheric plasma-activated solutions (PAS) have shown their promissing application in cancer treatment. Similar as the common direct cold plasma treatment, PAS shows a selective anti-cancer capacity in vitro and in vivo. However, different from the direct cold atmospheric plasma (CAP) treatment, PAS can be stored for a long time and can be used without dependence on a CAP device. The research on PAS is gradually becoming a hot topic in plasma medicine. Objectives: In this review, we gave a concise but comprehensive summary on key topics about PAS including the development, current status, as well as the main conclusions about the anti-cancer mechanism achieved in past years. The approaches to make strong and stable PAS are also summarized.

scholarly journals Formulation and in vitro evaluation of self-nanoemulsifying liquisolid tablets of furosemide

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Lena Dalal ◽  
Abdul Wahab Allaf ◽  
Hind El-Zein
Keyword(s):  
Theoretical Model ◽  
Castor Oil ◽  
In Vivo Studies ◽  
Coating Materials ◽  
Peg 400 ◽  
The Mean ◽  
Usp Apparatus ◽  
Solid System

AbstractSelf-nanoemulsifying drug delivery systems (SNEDDS) were used to enhance the dissolution rate of furosemide as a model for class IV drugs and the system was solidified into liquisolid tablets. SNEDDS of furosemide contained 10% Castor oil, 60% Cremophor EL, and 30% PEG 400. The mean droplets size was 17.9 ± 4.5 nm. The theoretical model was used to calculate the amounts of the carrier (Avicel PH101) and coating materials (Aerosil 200) to prepare liquisolid powder. Carrier/coating materials ratio of 5/1 was used and Ludipress was added to the solid system, thus tablets with hardness of 45 ± 2 N were obtained. Liquisolid tablets showed 2-folds increase in drug release as compared to the generic tablets after 60 min in HCl 0.1 N using USP apparatus-II. Furosemide loaded SNEDDS tablets have great prospects for further in vivo studies, and the theoretical model is useful for calculating the adequate amounts of adsorbents required to solidify these systems.

Sign in / Sign up

Export Citation Format

Share Document