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[
Small,
2016]
A polydimethylsiloxane microchannel featuring sidewall sharp-edge structures and bare channels, and a piezoelement transducer is attached to a thin glass slide. When an external acoustic field is applied to the microchannel, the oscillation of the sharp-edge structures and the thin glass slide generate acoustic streaming flows which in turn rotate single cells and C. elegans in-plane and out-of-plane.
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[
N Z J Crop Hortic Sci,
2001]
Few nematodes infest the roots of hemp (Cannabis sativa L.) plants, and hemp plant extracts have been utilised as botanical nematicides. The responsible constituent may be Delta(9)-tetrahydrocannabinol (Delta(9)-THC). In humans, Delta(9)-THC exerts its effects via a family of G protein-coupled receptors, known as cannabinoid (CB) receptors. CB receptors are phylogenetically ancient, and occur in many vertebrates and invertebrates. We therefore searched for evidence of CB receptors in nematodes. All nematode cDNA sequences at GenBank, including the entire genome of Caenorhabditis elegans, were screened for homologs of human CB receptors using BLAST 2.0 as a sequence alignment search engine. We also searched for homologs of fatty acid amide hydrolase (FAAH), the enzyme in vertebrates that metabolises the endogenous ligands of CB receptors. Several C. elegans gene products with low homology to CB receptors and FAAH were identified. Close examination of these sequences revealed crippling substitutions at critical amino acid residues. These results suggest the genes for CB receptors are absent in C. elegans, and the nematicidal activities of Delta(9)-THC and Cannabis are not mediated through CB receptors.
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[
Worm Breeder's Gazette,
1981]
A 4 liter glass 'fermenter' has been used instead of Roux bottles in our lab for C. elegans mass liquid cultures. It is made of glass plates stuck together with silicone rubber. It is autoclavable at 120 C, and provided with an aluminium cover containing two noles, into which tubes, are sealed by silicone rubber. One tube (the shorter one) includes a 'weighted' valve, supplied with a movable but hole- covering glass ball. The other an inverted T, the horizontal arms of which are perforated with holes, the prefiltered condensed air entering via the vertical section. This apparatus is practical for both bacteria and C. elegans. New cultures are started by transferring the cover to a new, sterilized culture from an old one. [See Figure 1]
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[
Biochemistry,
2012]
Decapping scavenger (DcpS) enzymes catalyze the cleavage of a residual cap structure following 3' 5' mRNA decay. Some previous studies suggested that both m(7)GpppG and m(7)GDP were substrates for DcpS hydrolysis. Herein, we show that mononucleoside diphosphates, m(7)GDP (7-methylguanosine diphosphate) and m(3)(2,2,7)GDP (2,2,7-trimethylguanosine diphosphate), resulting from mRNA decapping by the Dcp1/2 complex in the 5' 3' mRNA decay, are not degraded by recombinant DcpS proteins (human, nematode, and yeast). Furthermore, whereas mononucleoside diphosphates (m(7)GDP and m(3)(2,2,7)GDP) are not hydrolyzed by DcpS, mononucleoside triphosphates (m(7)GTP and m(3)(2,2,7)GTP) are, demonstrating the importance of a triphosphate chain for DcpS hydrolytic activity. m(7)GTP and m(3)(2,2,7)GTP are cleaved at a slower rate than their corresponding dinucleotides (m(7)GpppG and m(3)(2,2,7)GpppG, respectively), indicating an involvement of the second nucleoside for efficient DcpS-mediated digestion. Although DcpS enzymes cannot hydrolyze m(7)GDP, they have a high binding affinity for m(7)GDP and m(7)GDP potently inhibits DcpS hydrolysis of m(7)GpppG, suggesting that m(7)GDP may function as an efficient DcpS inhibitor. Our data have important implications for the regulatory role of m(7)GDP in mRNA metabolic pathways due to its possible interactions with different cap-binding proteins, such as DcpS or eIF4E.
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[
J Infect Dis,
2015]
BACKGROUND: Elimination of onchocerciasis and lymphatic filariasis is targeted for 2020. Given the coincident Loa loa infections in Central Africa and the potential for drug resistance development, the need for new microfilaricides and macrofilaricides has never been greater. With the genomes of L. loa, Onchocerca volvulus, Wuchereria bancrofti, and Brugia malayi available, new drug targets have been identified. METHODS: The effects of the tyrosine kinase inhibitors imatinib, nilotinib, and dasatinib on B. malayi adult males, adult females, L3 larvae, and microfilariae were assessed using a wide dose range (0-100 M) in vitro. RESULTS: For microfilariae, median inhibitory concentrations (IC50 values) on day 6 were 6.06 M for imatinib, 3.72 M for dasatinib, and 81.35 M for nilotinib; for L3 larvae, 11.27 M, 13.64 M, and 70.98 M, respectively; for adult males, 41.6 M, 3.87 M, and 68.22 M, respectively; and for adult females, 42.89 M, 9.8 M, and >100 M, respectively. Three-dimensional modeling suggests how these tyrosine kinase inhibitors bind and inhibit filarial protein activity. CONCLUSIONS: Given the safety of imatinib in humans, plans are underway for pilot clinical trials to assess its efficacy in patients with filarial infections.
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[
J Parasitol,
1963]
Studies with parasitic and free-living nematodes in this laboratory have required large numbers of bacteria-free organisms. A procedure has been developed in which both larval and adult stages free themselves of debris by migrating through paper and glass beads, while the axenizing of concentrated antibiotics followed by prolonged holding in dilute antibiotics is achieved automatically without manipulation of the worms.
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[
Nematologica,
1970]
Free-living nematodes of the genera Aphelenchoides, Panagrellus, Turbatrix, and Caenorhabditis were successfully frozen in heat-sealed glass ampoules using dimethyl sulfoxide as a protectant. After 6 months storage in liquid nitrogen refrigerator (below -160C), living nematodes were recovered after thawing. The nematodes were slowly cooled to -22 +/- 1C and immediately transferred to liquid nitrogen at -196C.
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[
Worm Breeder's Gazette,
1976]
We have studied maternal effects in 23 zyg ts mutants to estimate the times of expression of genes whose products are required in embryogenesis. We have used the following three tests, called arbitrarily A, B, and C. A test: Heterozygous (m/+) L4's are shifted to 25 C and allowed to self-fertilize. If 100% of their eggs yield larvae (25% of which express the mutant phenotype as adults), then the mutant is scored as maternal (M). If 25% of the F1 eggs fail to hatch, then the mutant is scored as non-maternal (N). An M result indicates that expression of the + allele in the parent allows m/m zygotes to hatch and grow to adulthood. A result of N indicates the opposite: that the + allele must be expressed in the zygote for hatching to occur. Out of 23 zyg mutants tested, 3 were scored N and 20 were scored M in the A test. Therefore, for most of the genes defined by these mutants, expression in the parent is sufficient for zygote survival, even if the gene is not expressed in the zygote. B test: Homozygous (m/m) hermaphrodites reared at 25 C are mated with N2 (+/+) males. If eggs fail to hatch at 25 C, but mated hermaphrodites shifted to 16 C produce cross progeny to give proof of mating, then the mutant is scored M. If cross progeny appear in the 25 C mating, then the mutant is scored N. An M result indicates that expression of the + allele in the zygote is not sufficient to allow m/+ progeny of an m/m hermaphrodite to survive. Conversely an N result indicates either that zygotic expression of the + allele is sufficient for survival, or that a sperm function or factor needed for early embryogenesis can be supplied paternally (see C test below). Out of the 23 zyg mutants tested, 11 were scored M and 12 were scored N. The combined results of A and B tests and their simplest interpretation are as follows. Ten mutants are M,M; the genes defined by these mutants must be expressed in the hermaphrodite parent for the zygote to survive. Ten mutants are M,N; these genes can be expressed either in the parent or in the zygote. Two mutants are N,N; these genes must be expressed in the zygote. One mutant is N,M; this gene must be expressed both in the maternal parent and in the zygote. C test: Homozygous (m/m) hermaphrodites reared at 25 C are mated with heterozygous (m/+) males. If rescue by a +/+ male in the B test depends on the + allele, then only half the cross progeny zygotes of a C test mating (m/+ male x m/m hermaphrodite) should survive. However, if rescue depends on a function or cytoplasmic component from the male sperm, then all the cross progeny zygotes in a C test should survive. Of the 10 M,N mutants, 6 have been C tested; one exhibited paternal rescue independent of the + allele. The A and B tests also were carried out on 16 mutants that arrest before the L3 molt (acc mutants). In the A test on 2 of these mutants, all m/m progeny of m/+ parents grew to adulthood at 25 C. Therefore, parental contributions are sufficient to overcome a progeny mutational block as late as the L2 stage. All 16 acc mutants scored N in the B test.
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[
Worm Breeder's Gazette,
1994]
cej-1 Encodes a Novel Protein with Poly-Threonine Motif M. L. A. Khanl, M. Tabish, T. Fukushigel1 S. Tsukita2, M. Itoh , Sh. Tsukita , and S. S. Siddiqui. (1): Lab. of Molecular Biology, Dept of Ecological Engg. Toyohashi Univ. Technology, Toyohashi 441, and (2). National Institute for Physiological Sciences, Okazaki 444, Japan.
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[
Mech Ageing Dev,
2009]
Energy production via oxidative phosphorylation generates a mitochondrial membrane potential (DeltaPsi(m)) across the inner membrane. In this work, we show that a lower DeltaPsi(m) is associated with increased lifespan in Caenorhabditis elegans. The long-lived mutants
daf-2(
e1370),
age-1(
hx546),
clk-1(
qm30),
isp-1(
qm150) and
eat-2(
ad465) all have a lower DeltaPsi(m) than wild type animals. The lower DeltaPsi(m) of
daf-2(
e1370) is
daf-16 dependent, indicating that the insulin-like signaling pathway not only regulates lifespan but also mitochondrial energetics. RNA interference (RNAi) against 17 genes shown to extend lifespan also decrease DeltaPsi(m). Furthermore, lifespan can be significantly extended with the uncoupler carbonylcyanide-3-chlorophenylhydrazone (CCCP), which dissipates DeltaPsi(m). We conclude that longevity pathways converge on the mitochondria and lead to a decreased DeltaPsi(m). Our results are consistent with the 'uncoupling to survive' hypothesis, which states that dissipation of the DeltaPsi(m) will extend lifespan.