Pidgeon SE et al. (2017) Bioconjug Chem "Cell Wall Remodeling of Staphylococcus aureus in Live C. elegans."

Pidgeon SE, Pires MM

[Bioconjug Chem, 2017]

Peptidoglycan (PG) scaffolds are critical components of bacterial cell walls. They counter internal turgor pressure to prevent lysis and protect against external insults. It was recently discovered that various types of bacteria release large quantities of PG building blocks (D-amino acids) into their surrounding medium. Cultured bacteria were also found to incorporate D-amino acids (both natural and synthetic) from the medium directly into their PG scaffold. Together, these two processes may potentially function, in concert, to metabolically remodel PG in live host organisms. Yet, demonstration that bacteria can decorate their cell surfaces with exogenous D-amino acids was limited to in vitro culture conditions. We present the first evidence that bacteria remodel their cell wall PG in a live host animal. A tetrazine click partner was conjugated onto the sidechain of a D-amino acid to capture incorporation into the bacterial PG scaffold using a complementary click-reactive fluorophore. Staphylococcus aureus infected Caenorhabditis elegans treated with exogenous D-amino acids readily revealed in vivo PG labeling. These results suggest that extracellular D-amino acids may provide pathogens with a mode of late-stage in vivo cell surface remodeling.

Xu HY et al. (2023) Plant Foods Hum Nutr "Anti-Oxidative and Anti-Aging Effects of Probiotic Fermented Ginseng by Modulating Gut Microbiota and Metabolites in Caenorhabditis elegans."

Zhou WJ, Gong SY, Xu HY, Peng N, Chen ZX, Zhang HB, Li QC, Liu B, Zeng F

[Plant Foods Hum Nutr, 2023]

Antioxidative and antiaging abilities of probiotic fermented ginseng (PG) were evaluated in Caenorhabditis elegans (C. elegans). Lifespan and effect on heat stress and acute oxidative stress in C. elegans were significantly enhanced by PG. Antioxidative enzymes such as T-SOD, GSH-PX, CAT were significantly up-regulated, and MDA, ROS and apoptosis levels were significantly down-regulated. At the same time, PG exerted antioxidant and anti-aging activities by reducing the expression of DAF-2 mRNA and increasing the expression of SKN-1 and SOD-3 mRNA in C. elegans. In addition, the mechanism of antioxidative and antiaging activities of PG was explored through gut microbiota sequencing and untargeted metabolomics. The results of gut microbiota indicated that PG could significantly improve the composition and structure of microbes in the gut of C. elegans, and the relative abundance of beneficial bacteria was up-regulated. Untargeted metabolomic results elucidated that PG modulated antioxidant and antiaging activities through neuroactive ligand-receptor interaction, Citrate cycle (TCA cycle), pyruvate metabolism, ascorbate and aldarate metabolism and D-Arginine and D-ornithine metabolism of C. elegans. These results indicated that PG had excellent antioxidant and anti-aging activities, providing research value for the development of functional foods and improvement of aging-related diseases.

Bennet MD et al. (1983) J Cell Sci "DNA density in mitotic and meiotic metaphase chromosomes of plants and animals."

Ward JP, Smith JB, Bennet MD, Heslop-Harrison JS

[J Cell Sci, 1983]

Studies of chromosome disposition at metaphase using serial thin-sectioning and three-dimensional reconstruction techniques have produced accurate estimates of the total volume of chromosomes per cell in 15 plant and two animal species. Comparing this character with the 4C DNA amount showed no indication of systematic differences in DNA density between either organisms with widely different (>200-fold) C values or different groups or organisms. For example, there was no significant difference between the density of DNA in somatic metaphase chromosomes of man (0.141 pg/um3) and its mean in 14 angiosperm plant species (0.182 pg/um3), or between four dicotyledons (0.180 pg/um3) and 10 monocotyledons (0.182 pg/um3). However, evidence was found showing that DNA density can vary significantly within a species. Thus, although the total chromosome volume per cell was closely correlated (r>0.97) with 4C DNA amount in somatic and meiotic cells, the density of DNA in metaphase chromosomes was significantly lower in meiocytes (0.131 pg/um3) than in somatic metaphase cells (0.179

Kim B et al. (2019) Sci Rep "Differential effects of alkyl gallates on quorum sensing in Pseudomonas aeruginosa."

Choi HY, Kwak JH, Kim B, Kim WG, Park JS

[Sci Rep, 2019]

Virulence factors and biofilms constitute attractive targets for the prevention of infections caused by multidrug-resistant bacteria. Among alkyl gallates, propyl gallate (PG) and octyl gallate (OG) are used as food preservatives. Here we found that alkyl gallates differentially affect virulence, biofilm formation, and quorum sensing (QS) in Pseudomonas aeruginosa. Ethyl gallate (EG), PG, and butyl gallate (BG) inhibited biofilm formation and virulence factors including elastase, pyocyanin, and rhamnolipid, in P. aeruginosa without affecting cell viability by antagonizing the QS receptors LasR and RhlR. PG exhibited the most potent activity. Interestingly, hexyl gallate (HG) inhibited the production of rhamnolipid and pyocyanin but did not affect elastase production or biofilm formation. Notably, OG inhibited the production of rhamnolipid and pyocyanin but stimulated elastase production and biofilm formation. Analysis of QS signaling molecule production and QS gene expression suggested that HG inhibited RhlR, while OG activated LasR but inhibited PqsR. This mechanism was confirmed using QS mutants. Additionally, PG prevented the virulence of P. aeruginosa in Caenorhabditis elegans and a mouse model. This is the first report of the differential effects of alkyl gallates on QS systems and PG has great potential as an inhibitor of the virulence and biofilm formation of P. aeruginosa.

Hu M et al. (2021) Dev Dyn "Mechanisms of TGFB in prostaglandin synthesis and sperm guidance in C. elegans."

Serra R, Prasain JK, Hu M, Tiwary E, Miller M

[Dev Dyn, 2021]

BACKGROUND: The transparent epidermis of C. elegans makes it an attractive model to study sperm motility and migration within an intact reproductive tract. C. elegans synthesize specific F-series prostaglandins (PGFs) that are important for guiding sperm toward the spermatheca. These PGFs are synthesized from polyunsaturated fatty acid (PUFA) precursors, such as arachidonic acid (AA), via a novel pathway, independent of the classical cyclooxygenases (Cox) responsible for most PG synthesis. While the enzyme(s) responsible for PG synthesis has yet to be identified, the DAF-7 TGFB pathway has been implicated in modulating PG levels and sperm guidance. RESULTS: We find that the reduced PGF levels in daf-1 Type I receptor mutants are responsible for the sperm guidance defect. The lower level of PGs in daf-1 mutants is due in part to the inaccessibility of AA. Finally, lipid analysis and assessment of sperm guidance in daf-1;daf-3 double mutants suggest DAF-3 suppresses PG production and sperm accumulation at the spermatheca. Our data suggest that DAF-3 functions in the nervous system, and possibly the germline, to affect sperm guidance. CONCLUSION: The C. elegans TGFB pathway regulates many pathways to modulate PG metabolism and sperm guidance. These pathways likely function in the nervous system and possibly the germline. This article is protected by copyright. All rights reserved.

Panitz D et al. (2015) BMC Pharmacol Toxicol "A C. elegans model of electronic cigarette use: Physiological effects of e-liquids in nematodes."

Swamy H, Panitz D, Nehrke K

[BMC Pharmacol Toxicol, 2015]

BACKGROUND: Electronic cigarettes (e-cigs) have recently become very popular particularly among the younger generation. These nicotine delivery devices are viewed as a preferable alternative to more conventional forms of tobacco use and are thought to reduce the risk of chronic obstructive pulmonary disease, the third leading cause of death worldwide. However, there is very little data available on the consequences of e-cig use, though recently nicotine-independent inflammatory responses have been reported. The genetic model organism Caenorhabditis elegans is a soil nematode whose cell biology is remarkably well conserved with mammals. Here, we used C. elegans to test the physiologic effects of e-liquids used to refill e-cigs. METHODS: Larval worms were exposed from hatching onwards to low concentrations (0.2%) of e-liquids, distilled e-liquid vapor, propylene glycol (PG), or M9 buffer as a negative control. E-liquids tested included grape, menthol, and V2 Red "classic tobacco" flavors. Nicotine (48ppm) was tested as a second level variable. Stereotypical physiological outputs were then measured, including developmental rate, fecundity, locomotion, lifespan, and the induction of canonical stress signaling pathways. RESULTS: A small but significant impairment of developmental rate and brood size was observed for PG and V2 Red treated worms compared to the negative control. Worms treated with e-liquids containing nicotine fared significantly worse than those that did not, but vaporization did not increase toxicity. Finally, both PG and V2 Red e-liquid induced an oxidative stress response in the absence of nicotine. CONCLUSIONS: PG exposure is sufficient to induce an oxidative stress response in nematodes, while nicotine is not. Both PG and nicotine independently influence physiologic measures of health and viability. The e-liquid flavorings did not significantly impact outcomes and there was no evidence for vaporization altering toxicity. These data suggest that the major physiologically significant component of e-liquids besides nicotine is likely the common solvent PG. We conclude that C. elegans are an appropriate model to rapidly assess parameters that may contribute to the basic cell biological effects of e-cigs.

Zhang W et al. (2016) Cell Mol Neurobiol "Shengmai Formula Ameliorates Pathological Characteristics in AD C.elegans."

Zhang W, Zhang Z, Wang X, Wang D, Zhi D, Ren H, Fei D, Zhu H, Li H

[Cell Mol Neurobiol, 2016]

Shengmai (SM) formula, a classical traditional Chinese medicine formula, is composed of Panax ginseng (Pg), Ophiopogon japonicus (Oj), and Schisandra Chinesis (Sc). SM has been clinically used to treat heart failure and ischemic heart disease. Although SM formula has been reported to be potential for fighting against Alzheimer's disease (AD) by previous works, there are many gaps in our knowledge on its usage in AD treatment on an organism level and will then need to be further clarified. In this study, transgenic Caenorhabditis elegans expressing human A1-42 are used to evaluate SM formula efficacy to treat AD phenotype and to investigate its underlying mechanism. The results showed that SM formula ameliorated AD pathological characteristics of paralysis behavior and chemotaxis defect in transgenic C.elegans. With SM treatment, the number of A deposits decreased, the levels of gene expressions of hsp16-2, hsp16-41, ace-1, ace-2, and TNFA1P1 homolog genes were down-regulated. Our results also showed that Oj exhibited more stronger effect on delaying paralysis in worms than Pg and Sc did, and synergistic action was observed between Pg and Oj, and Sc further enhanced the activity of Pg/Oj combination on delaying paralysis behavior. Further, SM with herbs of Pg, Oj, and Sc at a dose proportion of 9:9:6 exhibited superior therapeutic efficacy in comparison with herbs at other dose proportions. After SM formula extracted by ethanol, it delayed AD symptoms on a wider dose from 0.2 to 10.0mg/mL with no toxic effect. These results provided more evidence for SM formula being potential to be used to treat AD.

Chitwood DJ et al. (1990) J Nematol "Ecdysteroids in Axenically Propagated Caenorhabditis elegans and Culture Medium."

Chitwood DJ, Feldlaufer MF

[J Nematol, 1990]

Ecdysteroids (insect molting hormones) from Caenorhabditis elegans were chromatographically purified and quantified by radioimmunoassay. Nematodes from semidefined medium contained the immunoreactive equivalent of 460 pg ecdysone per gram dry weight. Culture medium, however, contained the immunoreactive equivalent of 68 times the quantity within the nematodes. In a defined medium lacking immunoreactivity, C. elegans contained 520 pg ecdysone equivalents per gram dry weight but reproduced slowly. Reproduction of C. elegans in defined medium was enhanced by formulation in agar. Propagation of C. elegans in either agar-based or aqueous defined medium supplemented with [(1)C]cholesterol of high specific activity failed to result in production of radiolabeled free ecdysteroids or polar or apolar ecdysteroid conjugates. Failure to demonstrate ecdysteroid biosynthesis in C. elegans raises questions about the ecdysteroids identified previously in nematodes being products of endogenous biosynthesis, a necessary condition for these compounds to be nematode hormones.

Wierzchowski J et al. (2007) Nucleosides Nucleotides Nucleic Acids "Kinetics of C. elegans DcpS cap hydrolysis studied by fluorescence spectroscopy."

Davis RE, Jankowska-Anyszka M, Pietrzak M, Wierzchowski J, Darzynkiewicz E, Jemielity J, Kalek M, Bojarska E, Stepinski J

[Nucleosides Nucleotides Nucleic Acids, 2007]

DcpS (scavenger decapping enzyme) from nematode C. elegans readily hydrolyzes both monomethyl- and trimethylguanosine cap analogues. The reaction was followed fluorimetrically. The marked increase of fluorescence intensity after the cleavage of pyrophosphate bond in dinucleotides was used to determine K(m) and V(max)values. Kinetic parameters were similar for both classes of substrates and only slightly dependent on pH. The hydrolysis was strongly inhibited by methylene cap analogues (m(7)Gp(CH(2))ppG and m(7)Gpp(CH(2))pG) and less potently by ARCA (m(7,3'' O)GpppG).

Wu Y et al. (2018) Mol Biol Cell "Single molecule dynamics of the P granule scaffold MEG-3 in the C. elegans zygote."

Griffin EE, Han B, Singh A, Gauvin TJ, Wu Y, Smith J

[Mol Biol Cell, 2018]

During the asymmetric division of the C. elegans zygote, germ (P) granules are disassembled in the anterior cytoplasm and stabilized/assembled in the posterior cytoplasm, leading to their inheritance by the germline daughter cell. P granule segregation depends on MEG-3 and MEG-4, which are enriched in P granules and in the posterior cytoplasm surrounding P granules. Here, we use single molecule imaging and tracking to characterize the reaction/diffusion mechanisms that underpin MEG-3::Halo segregation. We find that the anteriorly-enriched RNA-binding proteins MEX-5 and MEX-6 suppress the retention of MEG-3 in the anterior cytoplasm, leading to MEG-3 enrichment in the posterior. We provide evidence that MEX-5/6 may work in conjunction with PLK-1 kinase to suppress MEG-3 retention in the anterior. Surprisingly, we find that the retention of MEG-3::Halo in the posterior cytoplasm surrounding P granules does not contribute significantly to the maintenance of P granule asymmetry. Rather, our findings suggest that the formation of the MEG-3 concentration gradient and the segregation of P granules are two parallel manifestations of MEG-3's response to upstream polarity cues. Movie S1 Movie S1 near-TIRF imaging of PGL-1::GFP. Movie S2 Movie S2 near-TIRF imaging of MEG-3::Halo and PGL-1::GFP. Movie S3 Movie S3 near-TIRF imaging of Meg-3::meGFP. Movie S4 Movie S4 Spinning disk imaging of MEG-3::Halo and PGL-1::GFP. Movie S5 Movie S5 near-TIRF imaging of Meg-3::meGFP and PGL-1::GFP in an mbk-2(RNAi) embryo. Movie S6 Movie S6 near-TIRF imaging of Meg-3::meGFP and PGL-1::GFP in an mex-5/6(RNAi) embryo. Movie S7 Movie S7 near-TIRF imaging of Meg-3::meGFP and PGL-1::GFP in an mex-5(T186A);mex-6(RNAi) embryo. Movie S8 Movie S8 near-TIRF imaging of Meg-3::meGFP and PGL-1::GFP in an plk-1(RNAi) embryo. Movie S9 Movie S9 near-TIRF imaging of Meg-3::meGFP and PGL-1::GFP embryos. FD to PG transition. Movie S10 Movie S10 near-TIRF imaging of Meg-3::meGFP and PGL-1::GFP embryos. FD to PG to SD transition. Movie S11 Movie S11 near-TIRF imaging of Meg-3::meGFP and PGL-1::GFP embryos. SD to PG transition. Movie S12 Movie S12 near-TIRF imaging of Meg-3::meGFP and PGL-1::GFP embryos. SD to PG to SD transition.