Quantitative Assessment of Fat Levels in<i>Caenorhabditis elegans</i>Using Dark Field Microscopy

Fouad, Anthony D; Pu, Shelley; Teng, Shelly; Mark, Julian R; Fu, Moyu; Zhang, Kevin; Huang, Jonathan; Raizen, David M.; Fang-Yen, Christopher

doi:10.1534/g3.117.040840

Cited by 15 publications

(17 citation statements)

References 34 publications

(51 reference statements)

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“…Such variability could arise from differences in the age of the worms. As previously noted by Fouad et al (39), the fat content of C. elegans increases quickly between L1 and L2. According to the mixing rule in Eq.…”

Section: Resultssupporting

confidence: 71%

Acoustic Compressibility of Caenorhabditis elegans

Baasch

Reichert

Lakämper

et al. 2018

Biophysical Journal

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The acoustic compressibility of Caenorhabditis elegans is a necessary parameter for further understanding the underlying physics of acoustic manipulation techniques of this widely used model organism in biological sciences. In this work, numerical simulations were combined with experimental trajectory velocimetry of L1 C. elegans larvae to estimate the acoustic compressibility of C. elegans. A method based on bulk acoustic wave acoustophoresis was used for trajectory velocimetry experiments in a microfluidic channel. The model-based data analysis took into account the different sizes and shapes of L1 C. elegans larvae (255 5 26 mm in length and 15 5 2 mm in diameter). Moreover, the top and bottom walls of the microfluidic channel were considered in the hydrodynamic drag coefficient calculations, for both the C. elegans and the calibration particles. The hydrodynamic interaction between the specimen and the channel walls was further minimized by acoustically levitating the C. elegans and the particles to the middle of the measurement channel. Our data suggest an acoustic compressibility k Ce of 430 TPa À1 with an uncertainty range of 520 TPa À1 for C. elegans, a much lower value than what was previously reported for adult C. elegans using static methods. Our estimated compressibility is consistent with the relative volume fraction of lipids and proteins that would mainly make up for the body of C. elegans. This work is a departing point for practical engineering and design criteria for integrated acoustofluidic devices for biological applications.

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Section: Resultssupporting

confidence: 71%

Acoustic Compressibility of Caenorhabditis elegans

Baasch

Reichert

Lakämper

et al. 2018

Biophysical Journal

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“…During cultivation of the animals, we noted that kin-29 mutants had darker intestines than wild-type animals when viewed under bright field stereomicroscopy. An optically dense intestinal phenotype has been reported to correlate with elevated fat stores [61-63]. We therefore hypothesized that kin-29 mutants had increased fat stores.…”

Section: Resultsmentioning

confidence: 99%

“…The kin-29 increased fat phenotype was present throughout the animal life span from the first larval stage through the adult stage ( S3B Fig ). As controls for our fat ascertainment methods, we observed increased fat in animals mutant for the insulin receptor DAF-2 [62] and decreased fat in animals mutant for the gene eat-2 [63, 64], which is required for food intake [54, 65] ( Fig 4A-B ). To further characterize the excess fat phenotype of kin-29 mutants, we used a fluorescent gfp -reporter that marks the surface of lipid-droplets (DHS-3::GFP) [66].…”

Section: Resultsmentioning

confidence: 99%

A salt-induced kinase (SIK) is required for the metabolic regulation of sleep

Grubbs

Lopes

Linden

et al. 2019

Preprint

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ABSTRACTMany lines of evidence point to links between sleep regulation and energy homeostasis, but mechanisms underlying these connections are unknown. During C. elegans sleep, energetic stores are allocated to non-neural tasks with a resultant drop in the overall fat stores and energy charge. Mutants lacking KIN-29, the C. elegans homolog of a mammalian Salt-Inducible Kinase (SIK) that signals sleep pressure, have low ATP levels despite high fat stores, indicating a defective response to cellular energy deficits. Liberating energy stores corrects adiposity and sleep defects of kin-29 mutants. kin-29 sleep and energy homeostasis roles map to a small number of sensory neurons that act upstream of fat regulation as well as of central sleep-controlling neurons, suggesting hierarchical somatic/neural interactions regulating sleep and energy homeostasis. Genetic interaction between kin-29 and the histone deacetylase hda-4 coupled with subcellular localization studies indicate that KIN-29 acts in the nucleus to regulate sleep. We propose that KIN-29/SIK acts in nuclei of sensory neuroendocrine cells to transduce low cellular energy charge into the mobilization of energy stores, which in turn promotes sleep.HighlightsSleep is associated with fat mobilization and low ATP levelsMetabolic regulation of sleep requires the salt-induced kinase (SIK) homolog KIN-29KIN-29 acts in sensory neurons upstream of sleep-promoting neuronsNuclear localization of KIN-29 is required for the metabolic regulation of sleepA type 2 histone deacetylase acts down stream of KIN-29 in the regulation of sleep.Liberation of energy from fat-storage cells promotes sleep.Beta-oxidation promotes sleep.

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“…For example, kat-1, the major nematodes fat storage tissue, acts in the intestine. The gene transcription level of kat-1 was up-regulated during fat feeding [33] and down-regulated after hesperidin treatment [26] . In nematodes, four genes designated gpd-1 through gpd-4 encode glyceraldehyde-3-phosphate dehydrogenase, and △gpd-1 can cause greatly raised triglycerides [34] .…”

Section: Discussionmentioning

confidence: 95%

“…cDNA was obtained using M-MuLV First Strand cDNA Synthesis Kit (Sangon, Shanghai, China). Real-time PCR was performed using SYBR Green probes by QuantStudio® 3 System [26] . Primer sequences were listed in Table S1.…”

Section: Methodsmentioning

confidence: 99%

Inverse molecular docking reveals a novel function of thymol: inhibition of fat deposition induced by high-dose glucose in Caenorhabditis elegans

Ban

Zhang³

et al. 2020

Preprint

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Background As a natural product isolated from thyme oil in thyme, thymol (2-isopropyl-5-methylphenol) harbors antiviral, antioxidant, and other properties, and thus could be potentially used for the treatment of various diseases. However, the function of thymol has not been comprehensively studied.Methods Here, we applied an inverse molecular docking approach to identify unappreciated functions of thymol. Potential targets of thymol in humans were identiﬁed by the server of DRAR-CPI, and targets of interest were then assessed by GO and KEGG pathway analysis. Subsequently, homologous proteins of these targets in Caenorhabditis elegans were identified by Blast tool and their three-dimensional structures were achieved using Swiss-Model workspace. Interaction between thymol and the targeted proteins in worms was verified using AutoDock 4.0. To verify the activity of thymol on lipid deposition in vivo, the C. elegans model was established. The lipid content of nematodes induced by high-dose glucose was determined by Oil Red O and Nile Red staining, and gene expression related to fat accumulation was assessed by qRT-PCR. Results Analyses of the targets revealed that thymol could be potentially involved in the glycolysis/gluconeogenesis and fatty acid degradation pathways. Experiment results in vivo verified that 1 μg/mL and 5 μg/mL thymol treatment significantly reduced lipid deposition in glucose-induced nematodes. The result of qRT-PCR suggested that the decreased level of cpt-1, aco, fabp and tph-1 correlating with β-oxidation in nematodes exposed by 1mM glucose were upregulated after the exposure of thymol.Conclusions The results showed that thymol might lead to the acceleration of β-oxidation by upregulating cpt-1, aco, fabp and tph-1, causing the descent of lipid content in nematodes, which is potentially used for the treatment of chronic metabolic diseases associated with increased fatty acid deposition.

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Quantitative Assessment of Fat Levels inCaenorhabditis elegansUsing Dark Field Microscopy

Cited by 15 publications

References 34 publications

Acoustic Compressibility of Caenorhabditis elegans

Acoustic Compressibility of Caenorhabditis elegans

A salt-induced kinase (SIK) is required for the metabolic regulation of sleep

Inverse molecular docking reveals a novel function of thymol: inhibition of fat deposition induced by high-dose glucose in Caenorhabditis elegans

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