Wu HZ et al. (2006) Yi Chuan "[Computational analysis of signal peptide-dependent secreted protein in Caenorthaditis elegans ws123]"

Wu HZ, Li CY, Zhu YY, Bi YF

[Yi Chuan, 2006]

The internet-based softwares SignalP v3.0, TargetP v1.01, big-PI predictor and TMHMM v2.0 were combined to predict the signal peptides and the signal peptide-dependent secreted proteins from the 19855 ORFs in Caenorthaditis elegans ws123 genome. 1990 proteins were predicted to be secreted and to contain signal peptides among 19855 proteins, among which 1936 have SignalPase I signal peptide (containing 41 with RR-motif signal peptide), 53 have SignalPase II signal peptide and one has SignalPase IV signal peptide. The signal peptides of 742 secreted proteins include only H-domain and C-domain, but no typical N-domain; the signal peptides of other 1248 secreted proteins include all three domains. Although the amino acids constitution of the SignalPase I signal peptides were similar in general between Caenorthaditis elegans and prokaryote, there were apparently small differences, and the amino acid composition of Caenorthaditis elegans are more diverse and less conserved. But there are distinct differences on the amino acid composition of SignalPase II signal peptides. The signal peptides of Caenorthaditis elegans were more diverse than unicellular eukaryotic organism. The signal peptides of a few proteins were exactly the same. We used the BLAST 2 SEQUENECES aligning method to compare the homology among the secreted proteins with the same signal peptides. The alignment results indicated that the genes sharing the same signal peptide sequences were homologous to each other and were likely to have arisen from gene duplication.

Castillo-Quan JI et al. (2016) Cell "Metformin: Restraining Nucleocytoplasmic Shuttling to Fight Cancer and Aging."

Castillo-Quan JI, Blackwell TK

[Cell, 2016]

In this issue of Cell, Wu etal. employed C.elegans and human cell experiments to identify a pathway through which metformin increases lifespan and inhibits growth. A key transcriptional target, ACAD10, is activated when metformin induces nuclear exclusion of the GTPase RagC, thereby inhibiting mTORC1 through an unexpected mechanism.

Goode M et al. (1985) J Nematol "Behavior of Tethered Meloidogyne incognita."

Goode M, Dusenbery DB

[J Nematol, 1985]

The tethered-nematode technique was adapted for use with second-stage juveniles of Meloidogyne incognita. The data demonstrate that M. incognita exhibits the same patterns of behavior as adults of the free-living nematode, Caenorhabditis elegans. The principal differences are that M. incognita is slower and less regular in its behavior than C. elegans. The frequency of normal waves is about 0.2 Hz; that of reversal waves is about 0.06 Hz. Reversal bouts last about 1 minute. In response to a change in NaCl concentration, M. incognita modulates the probability of initiating a reversal bout in the same manner as C. elegans except that it responds more slowly and is repelled instead of attracted.

Ji Wu et al. (2002) East Coast Worm Meeting "Regulation of Touch Cell Functional Genes"

Ji Wu, Martin Chalfie

[East Coast Worm Meeting, 2002]

We have previously shown that egl-44 and egl-46 are two transcription regulators involved in the development of several types of neurons in C. elegans, with significant homology in other organisms, and that they repress the expression of touch cell-specific features in FLP neurons (Wu et al., 2001,Genes. Dev., 15: 789).

Hiebert T et al. (2017) MicroPubl Biol "Basal pharyngeal pumping elevated in C. elegans mod-5 mutants."

McCormick K, Chicas-Cruz A, Hiebert T

[MicroPubl Biol, 2017]

In C. elegans, the reuptake of serotonin (5-HT) is facilitated by mod-5, which encodes a 5-HT transporter that is orthologous to a human 5-HT transporter (SLC6A4). mod-5 has been shown to effect both feeding and locomotion in C. elegans (Ranganathan et al., 2001; Jafarau et al. 2011). We obtained and analyzed EPG data using a microfluidic device (NemaMetrix) for mod-5 null mutant strains, mod-5(n3314) (A, Exp 1 n=15; Exp 2 n=32) and mod-5(n822), (B, Exp 1 n=17; Exp 2 n=27) and N2 control worms (A, n=16 and 31; B, n=18 and 27 for Exp 1 and 2, respectively) in M9 saline buffer (2-minute recording duration). Mutations to the C. elegans serotonin reuptake transporter, mod-5, lead to an accumulation of serotonin at the synaptic cleft, which results in a significant increase in baseline pharyngeal pumping frequency in three out of four experiments (A, N2=0.10 0.04 and 0.09 0.03 Hz ; mod-5(n3314)=1.41 0.44 and 2.26 0.13 Hz; B, N2=0.98 0.42 and 0.44 0.08; mod-5(n822)=1.64 0.33 and 3.76 0.19 Hz; **p<0.005, ***p<0.0001, 2-tailed students t-test).

Brissette B et al. (2019) Neuron "Insulin-like Peptides as Agents of Social Change."

Ringstad N, Brissette B

[Neuron, 2019]

Many behaviors promote reproduction or food finding. These critical functions of behavior can conflict; successful reproductive strategies can grow populations to the point where food is depleted. In this issue of Neuron, Wu etal. (2019) show how the nematode C.elegans detects crowding to change feeding behavior by coupling pheromone sensing to signaling via insulin-like peptides.

Garca LR et al. (2000) West Coast Worm Meeting "Execution and regulation of male C. elegans spicule muscle contractions during mating"

Garca LR, Sternberg PW

[West Coast Worm Meeting, 2000]

HHMI & California Institute of Technology, Division of Biology, Pasadena, CA 91125 U.S.A. As the C. elegans male attempts to penetrate the hermaphrodite vulva with his spicules, the protractor muscles that are attached to these copulatory structures contract and relax rapidly such that the spicules prod the vulva slit at a frequency of 7.2 1.3 Hz. Phasic protractor muscle contractions persist until the vulva slit is partially penetrated. Once the vulva is breached, the protractor muscles contract tonically and the spicules extend completely into the hermaphrodite. The spicule muscles stay contracted for 75 20 seconds, sufficient time for sperm to transfer into the hermaphrodite. The male protractor muscles are innervated by the SPC motor neurons (2), and removal of these cells results in male impotency (1). The SPC neurons are essential for tonic, but not phasic spicule muscle contractions; the spicules of SPC-ablated males can not fully extend into the hermaphrodite, but can prod the vulva at a frequency of 5.1 1.1 Hz. The ACh agonists levamisole, nicotine, arecoline, and oxotremorine can stimulate the protractor muscles to contract; and the SPC motor neurons support the expression of the unc-17-encoded VAChT. Therefore ACh most likely regulates the contractile state of the spicule muscles. The ACh agonists differentially require egl-19 and unc-68-encoded calcium channels to mediate the behavioral output; thus suggesting that calcium mobilization from these channels might have non-overlapping roles during copulation. During mating the spicules of egl-19 males can prod the vulva at a frequency of 5.0 1.5 Hz, but they can not breach the vulva lips. In contrast, the spicules of unc-68 males can insert into the hermaphrodite, but prior to penetration, the spicules prod the vulva at a frequency of 0.48 1.4 Hz. Therefore, the UNC-68 channel is utilized in phasic muscle contractions, and the EGL-19 channel is required for tonic muscle contractions. 1. Liu, K.S., and Sternberg, P.W. (1995).Neuron 14, 79-89. 2. Sulston, J.E., Albertson, D.G., and Thomson, J.N. (1980). Dev. Biol. 78, 542-576.

Prevedel R et al. (2014) Nat Methods "Simultaneous whole-animal 3D imaging of neuronal activity using light-field microscopy."

Kato S, Yoon YG, Boyden ES, Raskar R, Prevedel R, Schrodel T, Zimmer M, Pak N, Vaziri A, Hoffmann M, Wetzstein G

[Nat Methods, 2014]

High-speed, large-scale three-dimensional (3D) imaging of neuronal activity poses a major challenge in neuroscience. Here we demonstrate simultaneous functional imaging of neuronal activity at single-neuron resolution in an entire Caenorhabditis elegans and in larval zebrafish brain. Our technique captures the dynamics of spiking neurons in volumes of 700 m x 700 m x 200 m at 20 Hz. Its simplicity makes it an attractive tool for high-speed volumetric calcium imaging.

Loizeau, Frederic et al. (2015) International Worm Meeting "Probing the viscoelasticity of the C. elegans body."

Mazzochette, Eileen, Loizeau, Frederic, Goodman, Miriam, Pruitt, Beth, Fechner, Sylvia, Nekimken, Adam, Vergassola, Massimo

[International Worm Meeting, 2015]

Gentle touch receptor neurons (TRNs) of C. elegans share many response dynamics with sensory neurons found in Pacinian and Meissner corpuscles in mammals [1]. For example, they show rapid adaptation and symmetrical on and off responses to the application and removal of mechanical cues [2]. Whether TRNs are frequency-dependent remain however unknown. In Pacinian corpuscles, the onion-like lamellar capsule acts as a mechanical band-pass filter between 20 Hz and 400 Hz [3]. Here, we ask whether the C. elegans body, and in particular the tissues engulfing the TRNs, is viscoelastic and how this property might play a role in the transduction of mechanical cues at low and high frequencies to the TRNs. To reach this goal, we developed a custom instrument capable of delivering defined force or displacement profiles to the worm body within the nN-mN or nm-mm range, respectively [4]. To apply the mechanical cues, silicon micro-cantilevers were fabricated using manufacturing processes derived from the integrated circuits industry. We integrated a piezoresistive strain gauge at their surface to detect the deflection of the micro-cantilever. Hence, the known dimensions of the micro-cantilevers coupled with a defined contact area with the worm body allow us to measure the applied force and indentation. The movement of the micro-cantilever is provided by a piezoelectric actuator controlled using a custom LabView interface and a field-programmable gate array. The controller manages data acquisition up to 10 kHz and feedback control in either displacement, i.e. displacement-clamp configuration, or force, i.e. force-clamp configuration. We achieved force and displacement step profiles with rising times below 3 ms and 1 ms, respectively. Sine waves have also been applied up to 200 Hz in force-clamp and up to 400 Hz in displacement-clamp. With sine stimuli of various frequencies, we are currently investigating the viscoelasticity of the worm body and its role in the mechanosensation of C. elegans.[1] A. Zimmerman, et al., Science, 346, 6212, 950-954, 2014[2] R. O'Hagan, et al., Nat. Neurosci., 8, 1, 43-50, 2005.[3] M. Sato, J. Physiol., 159, 3, 391-409, 1961.[4] S.-J. Park, et al., Rev. Sci. Instrum., 82, 4, 043703, 2011.

Miyakawa T et al. (2001) Bioelectromagnetics "Exposure of Caenorhabditis elegans to extremely low frequency high magnetic fields induces stress responses."

Miyakawa T, Yamamoto H, Yamada S, Ishimori T, Hosono R, Harada S

[Bioelectromagnetics, 2001]

Responses of the small hear shock protein gene, hsp-16, were examined in transgenic Caenorhabditis elegans exposed to electromagnetic fields. Expression of the hsp-16-lacZ gene was enhanced when transgenic animals were exposed to magnetic fields up to 0.5 T at 60 Hz. The hsp-16 promoter was more efficiently expressed at the embryonic than at the post-embryonic stage irrespective of exposure. Promoter activity was more sensitive to the stimulus in the intestine at the post-embryonic stage. Evidence is presented that the induction occurs at the transcriptional step of hsp-16.