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[
Sci Rep,
2018]
Staphylococcus aureus is a major cause of nosocomial infections and secretes a diverse spectrum of virulence determinants as well as forms biofilm. The emergence of antibiotic-resistant S. aureus highlights the need for alternative forms of therapeutics other than conventional antibiotics. One route to meet this need is screening small molecule derivatives for potential anti-infective activity. Using a previously optimized C. elegans - S. aureus small molecule screen, we identified a benzimidazole derivative, UM-C162, which rescued nematodes from a S. aureus infection. UM-C162 prevented the formation of biofilm in a dose-dependent manner without interfering with bacterial viability. To examine the effect of UM-C162 on the expression of S. aureus virulence genes, a genome-wide transcriptome analysis was performed on UM-C162-treated pathogen. Our data indicated that the genes associated with biofilm formation, particularly those involved in bacterial attachment, were suppressed in UM-C162-treated bacteria. Additionally, a set of genes encoding vital S. aureus virulence factors were also down-regulated in the presence of UM-C162. Further biochemical analysis validated that UM-C162-mediated disruption of S. aureus hemolysins, proteases and clumping factors production. Collectively, our findings propose that UM-C162 is a promising compound that can be further developed as an anti-virulence agent to control S. aureus infections.
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[
Metabolites,
2022]
BAM15 was recently screened as a protonophore uncoupler specifically for the mitochondrial membrane but not the plasma membrane. It is equally as potent as FCCP, but less toxic. Previously, mitochondrial uncoupling via DNP alleviates neurodegeneration in the nematode Caenorhabditis elegans during aging. Therefore, we investigated whether BAM15 uncouplers could phenotypically and functionally reduce neuronal defects in aged nematodes. We observed green fluorescence protein-tagged mechanosensory neurons and performed touch and chemotaxis assays during aging. Wild-type animals treated with both 50 uM BAM15 and 10 uM DNP showed reduced mechanosensory neuronal defects during aging, which correlates with the maintenance of touch responses and short-term memory during aging. Uncoupler mutant
ucp-4 also responded the same way as the wild-type, reducing neurodegeneration in 50 uM BAM15 and 10 uM DNP-treated animals compared to the DMSO control. These results suggest that 50 uM BAM15 alleviates neurodegeneration phenotypically and functionally in C. elegans during aging, potentially through mitochondrial uncoupling. In accordance with the preserved neuronal shape and function in aged C. elegans, 50 uM BAM15 extended the mean lifespan of both wild-type and
ucp-4 mutants.
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[
Chemosphere,
2021]
Perfluorooctane sulfonate (PFOS) is a well-known global persistent organic pollutant of grave concern to ecological and human health. Toxicity of PFOS to animals and humans are well studied. Although few studies have reported the behavioral effect of PFOS on nematode Caenorhabditis elegans, it's transgenerational effects were seldom studied. Therefore, we investigated the toxicity of PFOS on several behavioral responses besides bioaccumulation and transgenerational effects in C. elegans. In contrast to the several published studies, we used lower concentrations (0.5-1000 ug/L or 0.001-2.0 uM) that are environmentally relevant and reported to occur close to the contaminated areas. The 48 h median lethal concentration of PFOS was found to be 3.15 uM (1575 ug/L). PFOS (0.01 uM) caused severe toxicity to locomotion, and this effect was even transferred to progeny. However, after a few generations, the defect was rectified in the progeny of single-time exposed parent nematodes. Whereas, continuous exposure at 0.001 uM PFOS, no visible defects were observed in the progeny. PFOS (0.01 uM) also significantly decreased the brood size in a concentration-dependent manner. Besides, lifespan was affected by the higher concentration of PFOS (1.0 uM). These two behavioral endpoints, lifespan and reproduction defects, became less severe in the progeny. Chemotaxis plasticity was also significantly retarded by 1.0 uM PFOS compared to the control group. Results indicate that PFOS can exert severe neurobehavioral defects that can be transferred from parents to their offspring. The findings of this study have significant implications for the risk assessment of perfluorinated substances in the environment.
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[
Neurotoxicology,
2021]
The growing concern surrounding bisphenol A (BPA) has led to increased industrial production and application of its analog bisphenol S (BPS). The goals of this study were: (1) To examine the generational effects in the nematode C. elegans for up to three generations following developmental exposure to BPS (0.1, 1.0, 5.0 and 10.0 uM), and (2) To examine the neurotoxicity and metabolic toxicity in NODEF mouse offspring exposed to BPS (3 ug/kg BW) in utero throughout gestation once/day via oral pipette. First, worms were exposed to BPS developmentally for a single period of 48 hours and then propagated for 2 additional generations. Exposure to 0.1 and 1.0 uM BPS decreased lifespan and the number of progeny with an ability to recover in subsequent generations. In contrast, worms exposed to 5.0 or 10.0 uM BPS exhibited a continuous effect in the second generation, e.g., decreased lifespan and reduced number of progeny. Only worms exposed to 10.0 uM BPS continued to have a significant long-term effect (e.g., decreased lifespan) through the third generation. In addition, worms developmentally exposed to BPS at 5.0 uM and 10.0 uM also showed decreases in body bends. In contrast, worms exposed to 0.1 uM BPS exhibited a significant increase in head thrashes. When the multigenerational effects were examined by exposing worms to BPS for 48 hours developmentally at each generation for three generations, an accumulative effect was observed in worms treated with 0.1 or 1.0 uM BPS for two generations, but not for three generations, suggesting a threshold existed. Worms exposed to either 5.0 or 10.0 uM BPS demonstrated accumulative effects through two and three generations. When the developmental effects of BPS were studied in NODEF mice, offspring exposed gestationally exhibited behavioral deficits at 12, but not at 3, weeks of age. Specifically, female offspring had decreases in working and short-term memories while male offspring showed increases in hyperactivity and anxiety-like behaviors. In summary, this study demonstrates the sex-related effects of BPS in NODEF mouse offspring exposed in utero, along with the generational effects observed in C. elegans.
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[
MicroPubl Biol,
2021]
Glucose-6-phosphate dehydrogenase (G6PD) deficiency is an X-linked, recessive condition that causes intermittent jaundice or hemolytic anemia because of low NADPH levels in red blood cells. We performed steady-state enzyme kinetics with the recombinant C. elegans ortholog of human G6PD, GSPD-1, and two mutants containing amino acid changes found in human patients. The Km values for glucose-6-phosphate were 100 +/- 27 uM, 80 +/- 22 uM, and 1000 +/1 300 uM for the wild-type, D60N, and R252L GSPD-1 enzymes, respectively. The specific activities of the D60N and R252L mutants were 59% and 11%, respectively, of the wild-type value. Protein homology modeling suggested that the R252L mutation was more severe because the mutation caused a shift in the position of some active site residues. The D60N mutation may have affected the conformation of an outer loop of the enzyme. These data demonstrate that GSPD-1 is a promising model for human G6PD deficiencies, with the advantage that potential treatments could be studied in vivo in C. elegans.
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[
Front Chem,
2022]
Manumycin A is postulated to be a specific inhibitor against the farnesyltransferase (FTase) since this effect has been shown in 1993 for yeast FTase. Since then, plenty of studies investigated Manumycin A in human cells as well as in model organisms like Caenorhabditis elegans. Some studies pointed to additional targets and pathways involved in Manumycin A effects like apoptosis. Therefore, these studies created doubt whether the main mechanism of action of Manumycin A is FTase inhibition. For some of these alternative targets half maximal inhibitory concentrations (IC50) of Manumycin A are available, but not for human and C. elegans FTase. So, we aimed to 1) characterize missing C. elegans FTase kinetics, 2) elucidate the IC50 and Ki values of Manumycin A on purified human and C. elegans FTase 3) investigate Manumycin A dependent expression of FTase and apoptosis genes in C. elegans. C. elegans FTase has its temperature optimum at 40C with KM of 1.3 uM (farnesylpyrophosphate) and 1.7 uM (protein derivate). Whilst other targets are inhibitable by Manumycin A at the nanomolar level, we found that Manumycin A inhibits cell-free FTase in micromolar concentrations (Ki human 4.15 uM; Ki C. elegans 3.16 uM). Furthermore, our gene expression results correlate with other studies indicating that thioredoxin reductase 1 is the main target of Manumycin A. According to our results, the ability of Manumycin A to inhibit the FTase at the micromolar level is rather neglectable for its cellular effects, so we postulate that the classification as a specific FTase inhibitor is no longer valid.
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[
Electro-Optical Systems Design,
1979]
Microirradiation has been used as a tool for probing cells and subcellular organelles for the last fifty years. It is possible with good, high numerical aperture optics to obtain spot sizes of less than 1 um, which allows microsurgery to be performed at the cellular and subcellular levels. Valuable information has been obtained in this way concerning the functions of various cellular
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[
Trace Elements and Electrolytes,
2003]
Previously, we reported that the induction of vitellogenin mRNA in the larvae of Caenorhabditis elegans (C. elegans) can be used as a biomarker for short-term screening of environmental endocrine disrupters. Therefore, the present study was designed to determine if the induction of metallothionein (MT) mRNA in the larvae of C. elegans would be a biomarker for short-term screening of heavy metals. The larvae were exposed to various concentrations of cadmium (Cd), mercury (Hg), zinc chloride (Zn), cupper chloride (Cu) or lead acetate (Pb) for 2h. Cd (1, 10 and 100 uM) and Hg (0.01, 0.1, 1 and 10 uM) exposures resulted in the marked induction of MT-I and MT-II mRNAs in the larvae of C. elegans as measured by reverse transcription polymerase chain reaction. The Cd and Hg induction of MT-II was higher than that of MT-I mRNA, and concentration-dependent increase was observed in MT-II but not in MT-I. Time course analysis for MT-I and MT-II expressions with Cd and Hg were also determined. Cd induction of MT-I and MT-II mRNAs reached a peak at 2 h after the exposure (10 uM), and the levels of MT-II were higher than that of MT-I. For Hg, an initial peak of induction of MT-II mRNA occurred 15 minutes after the exposure (0.1 uM), and the levels reached maximum by 2 h. The initial peak of induction of MT-I mRNA occurred much later (about 2 h after Hg exposure) than MT-II mRNA. These results indicate that the induction of MT-II mRNA in the larvae of C. elegans can be used as a potential biomarker
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[
Pharmaceuticals (Basel),
2022]
Parasitic nematodes cause diseases in livestock animals and major economic losses to the agricultural industry worldwide. Nematodes of the order Strongylida, including Haemonchus contortus, are particularly important. The excessive use of anthelmintic compounds to treat infections and disease has led to widespread resistance to these compounds in nematodes, such that there is a need for new anthelmintics with distinctive mechanisms of action. With a focus on discovering new anthelmintic entities, we screened 400 chemically diverse compounds within the 'Pandemic Response Box' (from Medicines for Malaria Venture, MMV) for activity against H. contortus and its free-living relative, Caenorhabditis elegans-a model organism. Using established phenotypic assays, test compounds were evaluated in vitro for their ability to inhibit the motility and/or development of H. contortus and C. elegans. Dose-response evaluations identified a compound, MMV1581032, that significantly the motility of H. contortus larvae (IC50 = 3.4 +/- 1.1 uM) and young adults of C. elegans (IC50 = 7.1 +/- 4.6 uM), and the development of H. contortus larvae (IC50 = 2.2 +/- 0.7 uM). The favourable characteristics of MMV1581032, such as suitable physicochemical properties and an efficient, cost-effective pathway to analogue synthesis, indicates a promising candidate for further evaluation as a nematocide. Future work will focus on a structure-activity relationship investigation of this chemical scaffold, a toxicity assessment of potent analogues and a mechanism/mode of action investigation.
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[
Cell,
1983]
The body wall muscle cells of the nematode, Caenorhabditis elegans, contain two unique types of myosin heavy chain, A and B. We have utilized an immunochemical approach to define the structural location of these myosins within body wall muscle thick filaments. By immunofluorescence microscopy, myosin B antibodies label the thick filament-containing A-bands of body wall muscle with the exception of a thin gap at the center of each A-band, and myosin A antibodies react to form a medial fluorescent stripe within each A-band. The complexes of these monoclonal antibodies with isolated thick filaments were negatively stained and studied by electron microscopy. The myosin B antibody reacts with the polar regions of all filaments but does not react with a central 0.9 um zone. The myosin A antibody reacts with a central 1.8 um zone in all filaments but does not react with the polar regions.