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Sinnen, Brooke L., Schneider, Martin W., Liu, Qi, Tucker, Chandra L., Kennedy, Matthew J., Gottschalk, Alexander
[
International Worm Meeting,
2019]
Various biological processes from immune and endocrine signaling to synaptic transmission require regulated secretion. The most powerful and widely used tools to block those processes are clostridial neurotoxins, which specifically proteolyze conserved soluble N?ethylmaleimide?sensitive factor attachment protein receptor (SNARE) family proteins that are critical for vesicle docking and fusion. However, their applicability in the brain and elsewhere is restricted by controlling their activity with a high spatial and temporal resolution. Here we engineered botulinum neurotoxin serotype B (BoNT/B) light chain protease, which cleaves vesicle-associated membrane proteins (VAMPs) including the synaptic vesicle specific C. elegans homolog SNB-1, so that it can be activated with blue light. Therefore, a split protein complementation approach was used wherein the protein was cleaved into two fragments that could functionally reconstitute when fused to the improved light-induced dimerizer (iLID)-SspB photodimerizer system. We demonstrated that the photoactivatable BoNT/B (PA-BoNT) can persistently disrupt excitatory neurotransmission in a light-dependent manner. Thus we expressed different versions of the tool pan?neuronally in C. elegans to assess its effect on locomotion behavior. A partially automated video acquisition and analysis system was established for optogenetic behavioral assays of dozens of animals in parallel. We could show that one hour of pulsed blue light?activation suppressed coordinated swimming behavior by about 50%. This was reversible after 24h in the dark. Interestingly, fusing one part of the optogenetic tool to a synaptic vesicle localized membrane protein (SNG-1) was sufficient to increase its efficacy. Thus PA-BoNT fills a gap for localized and sustained silencing of neurons when compared to spatially diffusive chemogenetic (e.g. designer receptors exclusively activated by designer drugs - DREADDs) or temporally fast-acting optogenetic approaches (e.g. halorhodopsin - NpHR). This makes it particularly useful to study neuronal circuits in a behavioral or learning context. Comparable tools for inhibition of synapses use the photosensitizer miniature singlet oxygen generator (miniSOG) to generate damaging radicals that can have off-target effects. The defined molecular mechanism of action of PA-BoNT not only overcomes this limitation but allows shifting substrate specificity by applying the engineering strategy to other structurally conserved botulinum serotypes (and thus to different SNAREs like SNAP-25). In addition to blocking neurotransmitter release, this optogenetic tool will also have broad applicability to conditionally disrupting secretion of other bioactive molecules, e.g. neuromodulators or neuropeptides.
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[
International C. elegans Meeting,
1999]
In order to characterize the neural circuit of C. elagans, we construct a simple model by making use of the data table completed recently by Oshio et al . [1]. We assume that the signal of a neuron is calculated by the product of the signals from the neighboring neurons, and we investigate the touch sensitivity to continuous stimuli described by sinusoidal functions as defined in the rage from 0.0 to 1.0. We calculate the responses of the motor neurons by changing the frequencies of the stimuli. In our calculations, we change only the frequency w PLM for the input signal to the sensory neuron PLM, while the frequency for the other sensory neurons ALM, AVM and PVM is fixed to be a same value w 0 . We show that the output signals from the motor neurons A and B oscillate in time. We measure the minima of the oscillation for each w PLM value. The plot of the minima versus w PLM shows different hehaviors for the case of the neuron A and B. As for the signals from the neuron A, the values of the minima are widely distributed between 0.0 and 1.0 for all w PLM . As for the signals from the neuron B, on the other hand, the features are different for different w PLM values. (a) In the high frequency region of w PLM / w 0 0.4, the oscillation is simple harmonic and there exists only one minimum value (I min = 0.0). (b) As w PLM / w 0 is decreased, another minimum appears at a certain frequency, and the bifurcation takes place discontinuously. This behavior is different from usual continuous bifurcation observed in nonlinear systems. After a few discontinuous branching occur, signals with five periods can be seen in the intermediate frequency region of 0.3 w PLM / w 0 w PLM / w 0 [1] K. Oshio et al. ; C. elegans synaptic connectivity data'', Technical Report, CCEP, Keio Future No.1 (1998).
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Zhao T, Oswald NW, Li Y, Lin R, Wang C, Jaramillo J, Zhou A, McMillan EA, Douglas PM, MacMillan JB, Huang G, Luo M, Gao J, Mendiratta S, Lin Z, Wang Z, Niederstrasser H, Posner BA, Brekken RA, White MA
[
Nat Commun,
2018]
The originally published version of this Article contained an error in the spelling of the author Nathaniel W. Oswald, which was incorrectly given as Nathaniel W. Olswald. This has now been corrected inboth the PDF and HTML versions of the Article.
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[
Worm Breeder's Gazette,
1994]
THE MATERNAL GENE SKN-4 AND THE SPECIFICATION OF VENTRAL BLASTOMERE FATES IN THE EARLY C. ELEGANS EMBRYO Bruce Bowerman, Paula R. Martin, Christopher J. Thorpe, and Christopher A. Shelton. The Institute of Molecular Biology, University of Oregon, Eugene, OR 97403.
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[
Parasite Immunol,
1985]
The susceptibility of congenitally anemic, and mast cell deficient W/Wv mice to infection with Strongyloides ratti was examined. After a primary infection, W/Wv mice showed greater and more persistent peak larval counts than did normal littermates. Worm expulsion was also slower in W/Wv mice than in +/+ mice. Furthermore, difference in susceptibility was expressed as early as 24 h after infection, suggesting not only that protective mechanisms of the gut but also of the connective tissue were defective in W/Wv mice. Reconstitution with bone marrow or spleen cells from +/+ mice was effective in restoring the protective response in W/Wv mice, whereas thymocytes or mesenteric lymph nodes had no effect. Both connective tissue and mucosal mast cells were repaired in W/Wv mice after marrow reconstitution and infection. Since relatively long incubation period was required for the expression of such reconstituting activities, bone marrow cells seem to contain precursor cells of the effector and/or regulator cells.
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[
Chem Soc Rev,
2009]
On December 10, 2008 Osamu Shimomura, Martin Chalfie and Roger Tsien were awarded the Nobel Prize in Chemistry for "the discovery and development of the green fluorescent protein, GFP". The path taken by this jellyfish protein to become one of the most useful tools in modern science and medicine is described. Osamu Shimomura painstakingly isolated GFP from hundreds of thousands of jellyfish, characterized the chromophore and elucidated the mechanism of Aequorean bioluminescence. Martin Chalfie expressed the protein in E. coli and C. elegans, and Roger Tsien developed a palette of fluorescent proteins that could be used in a myriad of applications.
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[
Int J Parasitol,
2004]
Wolbachia pipientis is a bacterial endosymbiont associated with arthropods and filarial nematodes. In filarial nematodes, W. pipientis has been shown to play an important role in the biology of the host and in the immuno-pathology of filariasis. Several species of filariae, including the most important parasites of humans and animals (e.g. Onchocerca volvulus, Wuchereria bancrofti and Dirofilaria immitis) have been shown to harbour these bacteria. Other filarial species, including an important rodent species (Acanthocheilonema viteae), which has been used as a model for the study of filariasis, do not appear to harbour these symbionts. There are still several open questions about the distribution of W. pipientis in filarial nematodes. Firstly the number of species examined is still limited. Secondly, it is not clear whether the absence of W. pipientis in negative species could represent an ancestral characteristic or the result of a secondary loss. Thirdly, several aspects of the phylogeny of filarial nematodes are still unclear and it is thus difficult to overlay the presence/absence of W. pipientis on a tree representing filarial evolution. Here we present the results of a PCR screening for W. pipientis in 16 species of filariae and related nematodes, representing different families/subfamilies. Evidence for the presence of W. pipientis is reported for five species examined for the first time (representing the genera Litomosoides, Litomosa and Dipetalonema); original results on the absence of this bacterium are reported for nine species; for the remaining two species, we have confirmed the absence of W. pipientis recently reported by other authors. In the positive species, the infecting W. pipientis bacteria have been identified through 16S rDNA gene sequence analysis. In addition to the screening for W. pipientis in 16 species, we have generated phylogenetic reconstructions based on mitochondrial gene sequences (12S rDNA; COI), including a total of 28 filarial species and related spirurid nematodes. The mapping of the presence/absence of W. pipientis on the trees generated indicates that these bacteria have possibly been lost during evolution along some lineages of filarial nematodes.
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[
Worm Breeder's Gazette,
1994]
Cytology of degenerin-induced cell death in the PVM neuron David H. Hall, Guoqiang Gu+, Lei Gong#, Monica Driscoll#, and Martin Chalfie+, * Dept. Neuroscience, Albert Einstein College of Medicine, Bronx, N.Y. 10461 + Dept. Biological Sciences, Columbia University, New York, N.Y. 10027 # Dept. Molecular Biology and Biochemistry, Rutgers University, Piscataway, N.J. 08855
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[
Worm Breeder's Gazette,
1981]
I have made two modifications in the Ficoll method I originally described in WBG, vol. 3, #2. First, all Ficoll solutions are made 0. 1 M in NaCl to avoid shocking osmoticalIy sensitive worms like
unc-29(
e1072). Second, after sedimenting worms through 15% w/w Ficoll 400 ( 15', 300 x g), the worms are diluted with an equal volume of 0.1 M NaCl and floated on 35% w/w Ficoll (15', 300 x g) before washing 2x with 0.1 M NaCl. The Ficoll sedimentation removes dead or degenerated worms, cuticles, bacteria. The flotation removes crystalline debris sometimes occurring in worm cultures. We also find that special care to pipette out the last residue of bacterial medium (e.g. 3XD) before resuspending bacteria for worm growth is most conducive to obtaining uncontaminated worms.
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[
Pak J Pharm Sci,
2018]
We investigated the cellulase-assisted extraction and anti-ultraviolet activity of water-soluble polysaccharides from the root of Flammulina velutipes on Caenorhabditis elegans. A Box-Behnken design experiment with three factors and three levels, including enzymolysis temperature, microwave time, and microwave power, was designed on the basis of the results of single-factor experiments. For improving the polysaccharide yield of F. velutipes root, the following optimal extraction conditions were used: 52.67C enzymolysis temperature, 80s microwave time, and 144 W microwave power. Under optimal conditions, the actual measured value of the yield was 2.01% (w/w) and the predicted value was 2.06% (w/w). One fraction (FRP-2) was isolated and purified, and its characteristics were analyzed. The average mean molecular weight of FRP-2 was measured to be 2.60x10<sup>5</sup> Da, and its monosaccharide composition is mainly glucose. The sugar units are present both in the -configuration and -configuration. Moreover, FRP-2 exhibited certain anti-ultraviolet activity to C. elegans when the polysaccharide concentration ranged between 0.05mg/mL and 0.20mg/mL.