The effects of amidantel (BAY d 8815) and its deacylated derivative (BAY d 9216) on wild-type and resistant mutants of Caenorhabditis elegans

1986 ◽  
Vol 64 (6) ◽  
pp. 1310-1316 ◽  
Author(s):  
Robin A. Woods ◽  
Kathleen M. B. Malone ◽  
Cheryl A. Albuquerque ◽  
George Tomlinson
Keyword(s):  
Caenorhabditis Elegans ◽  
Acetylcholine Receptors ◽  
Egg Laying ◽  
Reproductive Capacity ◽  
Similar Amount ◽  
Wild Type ◽  
Drug Induced ◽  
Resistant Mutants ◽  
Anthelmintic Drugs

The anthelmintic drugs amidantel (BAY d 8815) and its deacylated derivative (BAY d 9216) inhibited the growth of wild-type (N2) Caenorhabditis elegans but had little effect on development or reproductive capacity. Inhibition of growth correlated well with drug-induced paralysis, both becoming maximal at around 1.0 mM concentration of either drug. Egg laying was delayed by about 24 h and the rate of laying was only about 60–70% of the controls. However, the period during which eggs were laid was extended by a similar amount and the total number of eggs laid was the same for controls and drug-treated worms. Five drug-resistant mutants (T114, T22, T26, T216, and T226) were isolated following ethylmethanesulphonate mutagenesis. All were shorter than N2 at 96 h on drug-free medium; their growth was not further impaired by either of the anthelmintic drugs. All except T114 exhibited a normal pattern of sexual maturation. Cultures of T114 at 96 h contained many immature worms. This mutant also exhibited the most impaired motility, being severely uncoordinated in liquid suspension. The other mutants could swim normally but were noticeably slower than N2. Genetic analysis indicated that each mutant was the result of a single genetic lesion, that the mutants were recessive, and that there were two genes for amidantel resistance (adt1 and adt2). In vitro studies on representatives of each class (T114 and T22) indicated a defect in the acetylcholine receptor. T22 mutants showed a moderate decrease in sensitivity towards typical cholinergic agonists as well as the anthelmintic drugs, while T114 mutants were apparently devoid of functional pharmacological acetylcholine receptors.

Streblus asper Lour. exerts MAPK and SKN-1 mediated anti-aging, anti-photoaging activities and imparts neuroprotection by ameliorating Aβ in Caenorhabditis elegans

2021 ◽  
pp. 1-17
Author(s):  
Mani Iyer Prasanth ◽  
James Michael Brimson ◽  
Dicson Sheeja Malar ◽  
Anchalee Prasansuklab ◽  
Tewin Tencomnao
Keyword(s):  
Oxidative Stress ◽  
Caenorhabditis Elegans ◽  
Stress Resistance ◽  
Vital Role ◽  
Transgenic Strain ◽  
Wild Type ◽  
Neuroprotective Effects ◽  
C Elegans ◽  
Streblus Asper

BACKGROUND: Streblus asper Lour., has been reported to have anti-aging and neuroprotective efficacies in vitro. OBJECTIVE: To analyze the anti-aging, anti-photoaging and neuroprotective efficacies of S. asper in Caenorhabditis elegans. METHODS: C. elegans (wild type and gene specific mutants) were treated with S. asper extract and analyzed for lifespan and other health benefits through physiological assays, fluorescence microscopy, qPCR and Western blot. RESULTS: The plant extract was found to increase the lifespan, reduce the accumulation of lipofuscin and modulate the expression of candidate genes. It could extend the lifespan of both daf-16 and daf-2 mutants whereas the pmk-1 mutant showed no effect. The activation of skn-1 was observed in skn-1::GFP transgenic strain and in qPCR expression. Further, the extract can extend the lifespan of UV-A exposed nematodes along with reducing ROS levels. Additionally, the extract also extends lifespan and reduces paralysis in Aβ transgenic strain, apart from reducing Aβ expression. CONCLUSIONS: S. asper was able to extend the lifespan and healthspan of C. elegans which was independent of DAF-16 pathway but dependent on SKN-1 and MAPK which could play a vital role in eliciting the anti-aging, anti-photoaging and neuroprotective effects, as the extract could impart oxidative stress resistance and neuroprotection.

scholarly journals Isolation, characterization and epistasis of fluoride-resistant mutants of Caenorhabditis elegans.

Genetics ◽  
1994 ◽  
Vol 136 (1) ◽  
pp. 145-154
Author(s):  
I Katsura ◽  
K Kondo ◽  
T Amano ◽  
T Ishihara ◽  
M Kawakami
Keyword(s):  
Caenorhabditis Elegans ◽  
Brood Size ◽  
Normal Growth ◽  
Fluoride Ion ◽  
Wild Type ◽  
Signal Transduction System ◽  
Nematode Caenorhabditis Elegans ◽  
C Elegans ◽  
Class 1 ◽  
Resistant Mutants

Abstract We have isolated 13 fluoride-resistant mutants of the nematode Caenorhabditis elegans. All the mutations are recessive and mapped to five genes. Mutants in three of the genes (class 1 genes: flr-1 X, flr-3 IV, and flr-4 X) are resistant to 400 micrograms/ml NaF. Furthermore, they grow twice as slowly as and have smaller brood size than wild-type worms even in the absence of fluoride ion. In contrast, mutants in the other two genes (class 2 genes: flr-2 V and flr-5 V) are only partially resistant to 400 micrograms/ml NaF, and they have almost normal growth rates and brood sizes in the absence of fluoride ion. Studies on the phenotypes of double mutants showed that class 2 mutations are epistatic to class 1 mutations concerning growth rate and brood size but hypostatic with respect to fluoride resistance. We propose two models that can explain the epistasis. Since fluoride ion depletes calcium ion, inhibits some protein phosphatases and activates trimeric G-proteins, studies on these mutants may lead to discovery of a new signal transduction system that controls the growth of C. elegans.

scholarly journals Mutations Conferring Aminoglycoside and Spectinomycin Resistance in Borrelia burgdorferi

2006 ◽  
Vol 50 (2) ◽  
pp. 445-452 ◽  
Author(s):  
Daniel Criswell ◽  
Virginia L. Tobiason ◽  
J. Stephen Lodmell ◽  
D. Scott Samuels
Keyword(s):  
16S Rrna ◽  
Borrelia Burgdorferi ◽  
Type Strain ◽  
Wild Type Strain ◽  
Small Subunit ◽  
Wild Type ◽  
Spectinomycin Resistance ◽  
E Coli ◽  
Resistant Mutants

ABSTRACT We have isolated and characterized in vitro mutants of the Lyme disease agent Borrelia burgdorferi that are resistant to spectinomycin, kanamycin, gentamicin, or streptomycin, antibiotics that target the small subunit of the ribosome. 16S rRNA mutations A1185G and C1186U, homologous to Escherichia coli nucleotides A1191 and C1192, conferred >2,200-fold and 1,300-fold resistance to spectinomycin, respectively. A 16S rRNA A1402G mutation, homologous to E. coli A1408, conferred >90-fold resistance to kanamycin and >240-fold resistance to gentamicin. Two mutations were identified in the gene for ribosomal protein S12, at a site homologous to E. coli residue Lys-87, in mutants selected in streptomycin. Substitutions at codon 88, K88R and K88E, conferred 7-fold resistance and 10-fold resistance, respectively, to streptomycin on B. burgdorferi. The 16S rRNA A1185G and C1186U mutations, associated with spectinomycin resistance, appeared in a population of B. burgdorferi parental strain B31 at a high frequency of 6 × 10−6. These spectinomycin-resistant mutants successfully competed with the wild-type strain during 100 generations of coculture in vitro. The aminoglycoside-resistant mutants appeared at a frequency of 3 × 10−9 to 1 ×10−7 in a population and were unable to compete with wild-type strain B31 after 100 generations. This is the first description of mutations in the B. burgdorferi ribosome that confer resistance to antibiotics. These results have implications for the evolution of antibiotic resistance, because the 16S rRNA mutations conferring spectinomycin resistance have no significant fitness cost in vitro, and for the development of new selectable markers.

The terminal differentiation factor LIN-29 is required for proper vulval morphogenesis and egg laying in Caenorhabditis elegans

Development ◽  
1997 ◽  
Vol 124 (21) ◽  
pp. 4333-4342 ◽  
Author(s):  
J.C. Bettinger ◽  
S. Euling ◽  
A.E. Rougvie
Keyword(s):  
Caenorhabditis Elegans ◽  
Terminal Differentiation ◽  
Egg Laying ◽  
Small Subset ◽  
Wild Type ◽  
Vulval Development ◽  
Genetic Mosaics ◽  
Hypodermal Cell ◽  
Heterochronic Gene ◽  
Final Molt

Caenorhabditis elegans vulval development culminates during exit from the L4-to-adult molt with the formation of an opening through the adult hypodermis and cuticle that is used for egg laying and mating. Vulva formation requires the heterochronic gene lin-29, which triggers hypodermal cell terminal differentiation during the final molt. lin-29 mutants are unable to lay eggs or mate because no vulval opening forms; instead, a protrusion forms at the site of the vulva. We demonstrate through analysis of genetic mosaics that lin-29 is absolutely required in a small subset of lateral hypodermal seam cells, adjacent to the vulva, for wild-type vulva formation and egg laying. However, lin-29 function is not strictly limited to the lateral hypodermis. First, LIN-29 accumulates in many non-hypodermal cells with known roles in vulva formation or egg laying. Second, animals homozygous for one lin-29 allele, ga94, have the vulval defect and cannot lay eggs, despite having a terminally differentiated adult lateral hypodermis. Finally, vulval morphogenesis and egg laying requires lin-29 activity within the EMS lineage, a lineage that does not generate hypodermal cells.

A normally attractive cell interaction is repulsive in two C. elegans mesodermal cell migration mutants

Development ◽  
1991 ◽  
Vol 113 (3) ◽  
pp. 797-803 ◽  
Author(s):  
M.J. Stern ◽  
H.R. Horvitz
Keyword(s):  
Cell Migration ◽  
Caenorhabditis Elegans ◽  
Premature Termination ◽  
Cell Interaction ◽  
Egg Laying ◽  
Wild Type ◽  
Mesodermal Cell ◽  
C Elegans ◽  
Somatic Gonad ◽  
Sex Myoblasts

In wild-type Caenorhabditis elegans hermaphrodites, two bilaterally symmetric sex myoblasts (SMs) migrate anteriorly to flank the precise center of the gonad, where they divide to generate the muscles required for egg laying (J. E. Sulston and H. R. Horvitz (1977) Devl Biol. 56, 110–156). Although this migration is largely independent of the gonad, a signal from the gonad attracts the SMs to their precise final positions (J. H. Thomas, M. J. Stern and H. R. Horvitz (1990) Cell 62, 1041–1052). Here we show that mutations in either of two genes, egl-15 and egl-17, cause the premature termination of the migrations of the SMs. This incomplete migration is caused by the repulsion of the SMs by the same cells in the somatic gonad that are the source of the attractive signal in wild-type animals.

scholarly journals Functional characterization of the rod visual pigment of the echidna (Tachyglossus aculeatus), a basal mammal

2012 ◽  
Vol 29 (4-5) ◽  
pp. 211-217 ◽  
Author(s):  
CONSTANZE BICKELMANN ◽  
JAMES M. MORROW ◽  
JOHANNES MÜLLER ◽  
BELINDA S.W. CHANG
Keyword(s):  
Half Life ◽  
Functional Characterization ◽  
Egg Laying ◽  
Sensory Transduction ◽  
Wild Type ◽  
Functional Variation ◽  
Bovine Rhodopsin ◽  
Tachyglossus Aculeatus

AbstractMonotremes are the most basal egg-laying mammals comprised of two extant genera, which are largely nocturnal. Visual pigments, the first step in the sensory transduction cascade in photoreceptors of the eye, have been examined in a variety of vertebrates, but little work has been done to study the rhodopsin of monotremes. We isolated the rhodopsin gene of the nocturnal short-beaked echidna (Tachyglossus aculeatus) and expressed and functionally characterized the protein in vitro. Three mutants were also expressed and characterized: N83D, an important site for spectral tuning and metarhodopsin kinetics, and two sites with amino acids unique to the echidna (T158A and F169A). The λmax of echidna rhodopsin (497.9 ± 1.1 nm) did not vary significantly in either T158A (498.0 ± 1.3 nm) or F169A (499.4 ± 0.1 nm) but was redshifted in N83D (503.8 ± 1.5 nm). Unlike other mammalian rhodopsins, echidna rhodopsin did react when exposed to hydroxylamine, although not as fast as cone opsins. The retinal release rate of light-activated echidna rhodopsin, as measured by fluorescence spectroscopy, had a half-life of 9.5 ± 2.6 min−1, which is significantly shorter than that of bovine rhodopsin. The half-life of the N83D mutant was 5.1 ± 0.1 min−1, even shorter than wild type. Our results show that with respect to hydroxylamine sensitivity and retinal release, the wild-type echidna rhodopsin displays major differences to all previously characterized mammalian rhodopsins and appears more similar to other nonmammalian vertebrate rhodopsins such as chicken and anole. However, our N83D mutagenesis results suggest that this site may mediate adaptation in the echidna to dim light environments, possibly via increased stability of light-activated intermediates. This study is the first characterization of a rhodopsin from a most basal mammal and indicates that there might be more functional variation in mammalian rhodopsins than previously assumed.

scholarly journals Peptide Deformylase in Staphylococcus aureus: Resistance to Inhibition Is Mediated by Mutations in the Formyltransferase Gene

2000 ◽  
Vol 44 (7) ◽  
pp. 1825-1831 ◽  
Author(s):  
Peter S. Margolis ◽  
Corinne J. Hackbarth ◽  
Dennis C. Young ◽  
Wen Wang ◽  
Dawn Chen ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Genomic Library ◽  
Specific Inhibitor ◽  
Peptide Deformylase ◽  
Cross Resistance ◽  
Loss Of Function ◽  
Wild Type ◽  
Chromosomal Dna ◽  
Resistant Mutants

ABSTRACT Peptide deformylase, a bacterial enzyme, represents a novel target for antibiotic discovery. Two deformylase homologs, defA and defB, were identified inStaphylococcus aureus. The defA homolog, located upstream of the transformylase gene, was identified by genomic analysis and was cloned from chromosomal DNA by PCR. A distinct homolog, defB, was cloned from an S. aureus genomic library by complementation of the arabinose-dependent phenotype of a P BAD -def Escherichia coli strain grown under arabinose-limiting conditions. Overexpression in E. coli of defB, but not defA, correlated to increased deformylase activity and decreased susceptibility to actinonin, a deformylase-specific inhibitor. ThedefB gene could not be disrupted in wild-type S. aureus, suggesting that this gene, which encodes a functional deformylase, is essential. In contrast, thedefA gene could be inactivated; the function of this gene is unknown. Actinonin-resistant mutants grew slowly in vitro and did not show cross-resistance to other classes of antibiotics. When compared to the parent, an actinonin-resistant strain produced an attenuated infection in a murine abscess model, indicating that this strain also has a growth disadvantage in vivo. Sequence analysis of the actinonin-resistant mutants revealed that each harbors a loss-of-function mutation in the fmt gene. Susceptibility to actinonin was restored when the wild-type fmt gene was introduced into these mutant strains. An S. aureusΔfmt strain was also resistant to actinonin, suggesting that a functional deformylase activity is not required in a strain that lacks formyltransferase activity. Accordingly, thedefB gene could be disrupted in an fmt mutant.

The genetics, ultrastructure, and tubulin polypeptides of mebendazole-resistant mutants of Caenorhabditis elegans

1989 ◽  
Vol 67 (10) ◽  
pp. 2422-2431 ◽  
Author(s):  
Robin A. Woods ◽  
Kathleen M. B. Malone ◽  
Andrew M. Spence ◽  
Wade J. Sigurdson ◽  
Edward H. Byard
Keyword(s):  
Caenorhabditis Elegans ◽  
Dense Material ◽  
Autosomal Gene ◽  
Wild Type ◽  
Electron Dense Material ◽  
C Elegans ◽  
Accessory Cells ◽  
Ethylmethane Sulphonate ◽  
Resistant Mutants ◽  
Β Tubulin

Mebendazole-resistant mutants of Caenorhabditis elegans were isolated following mutagenesis of the wild-type strain, N2, with ethylmethane sulphonate. The mutants define a single autosomal gene and are allelic to ben-1. They grow, move, and reproduce normally in the presence of mebendazole and are cross-resistant to albendazole, cambendazole, fenbendazole, methylbenzimidazole carbamate, and thiabendazole. Accumulations of membrane-bound, electron-dense material associated with the nervous tissue and associated cells are seen in electron micrographs of L3, L4, and adult stages of N2 grown in the presence of mebendazole, but are not found in the mutants. The electron-dense material appears to be associated with the accessory cells of the neuropil rather than with the neurons. The tubulins from wild type, N2, and the mutants were characterised by two-dimensional electrophoresis followed by silver staining and Western blotting with monoclonal antibodies to α- and β-tubulin. A single isotype of α-tubulin is apparent in both N2 and the mutants. One major and three minor β-tubulin isotypes, bt-1 to bt-3, can be discerned in N2; the minor isotype bt-2 is absent in all the mutants. These findings suggest that the isotype bt-2 is the primary site of action of benzimidazole-based drugs in C. elegans.

scholarly journals Caffeine-resistant mutants ofCaenorhabditis elegans

1987 ◽  
Vol 49 (2) ◽  
pp. 105-110 ◽  
Author(s):  
Philip S. Hartman
Keyword(s):  
Caenorhabditis Elegans ◽  
Pronounced Effect ◽  
Wild Type ◽  
Resistant Mutants

SummaryWild-typeCaenorhabditis elegansfails to reach adulthood if L1 larvae are incubated in the presence of 30 mM or greater concentrations of caffeine. Eleven mutants have been isolated in which caffeine has a less pronounced effect on development. The mutations are recessive, define two genes, and have been mapped. The mechanism(s) of resistance is unknown.

scholarly journals Flagellar microtubule dynamics in Chlamydomonas: cytochalasin D induces periods of microtubule shortening and elongation; and colchicine induces disassembly of the distal, but not proximal, half of the flagellum

1992 ◽  
Vol 117 (6) ◽  
pp. 1289-1298 ◽  
Author(s):  
WL Dentler ◽  
C Adams
Keyword(s):  
Average Rate ◽  
Cytochalasin D ◽  
Initial Length ◽  
Wild Type ◽  
Drug Induced ◽  
Distal Half ◽  
Proximal Half ◽  
Flagellar Assembly ◽  
Cytoplasmic Microtubules

To study the mechanisms responsible for the regulation of flagellar length, we examined the effects of colchicine and Cytochalasin D (CD) on the growth and maintenance of Chlamydomonas flagella on motile wild type cells as well as on pf 18 cells, whose flagella lack the central microtubules and are immobile. CD had no effect on the regeneration of flagella after deflagellation but it induced fully assembled flagella to shorten at an average rate of 0.03 microns-min. Cells remained fully motile in CD and even stubby flagella continued to move, indicating that flagellar shortening did not selectively disrupt machinery necessary for motility. To observe the effects of the drug on individual cells, pf 18 cells were treated with CD and flagella on cells were monitored by direct observation over a 5-hour period. Flagella on control pf 18 cells maintained their initial lengths throughout the experiment but flagella on CD-treated cells exhibited periods of elongation, shortening, and regrowth suggestive of the dynamic behavior of cytoplasmic microtubules observed in vitro and in vitro. Cells behaved individually, with no two cells exhibiting the same flagellar behavior at any given time although both flagella on any single cell behaved identically. The rate of drug-induced flagellar shortening and elongation in pf 18 cells varied from 0.08 to 0.17 microns-min-1, with each event occurring over 10-60-min periods. Addition of colchicine to wild type and pf 18 cells induced flagella to shorten at an average rate of 0.06 microns-min-1 until the flagella reached an average of 73% of their initial length, after which they exhibited no further shortening or elongation. Cells treated with colchicine and CD exhibited nearly complete flagellar resorption, with little variation in flagellar length among cells. The effects of these drugs were reversible and flagella grew to normal stable lengths after drug removal. Taken together, these results show that the distal half to one-third of the Chlamydomonas flagellum is relatively unstable in the presence of colchicine but that the proximal half to two-thirds of the flagellum is stable to this drug. In contrast to colchicine, CD can induce nearly complete flagellar microtubule disassembly as well as flagellar assembly. Flagellar microtubules must, therefore, be inherently unstable, and flagellar length is stabilized by factors that are sensitive, either directly or indirectly, to the effects of CD.

Sign in / Sign up

Export Citation Format

Share Document