Wada, H. et al. (2017) International Worm Meeting "The role of pheromones in behavioral changes during development of Caenorhabditis elegans."

Ishihara, T, Fujiwara, M, Wada, H., Butcher, R.A.

[International Worm Meeting, 2017]

Many animal species change their behavior according to their stage of development. Although such behavioral changes are thought to be important for their fitness, neural modifications that underlie the changes are not fully understood. Caenorhabditis elegans changes their olfactory preferences during development. Larvae exhibit a weak chemotactic response to a food-associated odor diacetyl, whereas adults exhibit a strong response. Previously, we showed that germline proliferation is required for the olfactory changes. The adult worms lacking germline cells failed to exhibit a strong response to diacetyl. In addition to that, we recently found that pheromone sensation is also required for the regulation. The adult worms which have defects either in pheromone synthesis or in a pair of pheromone-sensing neurons, ASK, failed to exhibit strong chemotactic response to diacetyl at adult regardless of whether their germline cells proliferates normally. Here, we have tested the possibility that germline proliferation might principally affect pheromone sensitivity, and the enhanced perception of pheromones subsequently cause the enhanced chemotaxis to diacetyl. By utilizing a Ca2+ indicator, YC3.60, we observed the neuronal responses of ASK sensory neurons to pheromone stimuli consisting of ascaroside C3, C6, C9. Contrary to our expectations, the responses to pheromones of adult worms lacking germline cells were indistinguishable from those of the adult animals with an intact germline. Thus, it seems that germline proliferation and pheromone sensation may act in parallel to regulate chemotaxis. Now we are planning to observe the neuronal activities in the olfactory circuit of pheromone-synthesis defective animals under diacetyl stimuli. Further analyses will reveal how the animals change their behavior by integrating their internal states and environmental inputs.

Thomas JH et al. (1994) Worm Breeder's Gazette "lin-36, a Class B Synthetic Multivulva Gene, Encodes a Novel Protein"

Thomas JH, Horvitz HR

[Worm Breeder's Gazette, 1994]

lin-36, a Class B Synthetic Multivulva Gene, Encodes a Novel Protein Jeffrey H. Thomas and H. Robert Horvitz, HHMI, Dept. Biology, MIT, Cambridge, MA 02139, USA

Fujiwara, M. et al. (2019) International Worm Meeting "Gonadal maturation changes chemotaxis to a food-associated odorant through a guanylyl cyclase GCY-28."

Fujiwara, M., Ishihara, T., Wada, H.

[International Worm Meeting, 2019]

Many animal species change their behavior depending on their stage of development. However, the mechanisms involved in translating their developmental stage into the modifications of the neuronal circuits that underlie the behavioral changes remain unknown. In Caenorhabditis elegans, the olfactory preferences are changed over development. Larvae exhibit a weak chemotactic response to the food-associated odor diacetyl, while adults exhibit a strong response. We found that the changes depend on germline cells which proliferate dramatically during the larval stages. We have shown that the germline cells affect neuronal responses to diacetyl in a circuitry comprised of a small set of neurons including an olfactory neuron, AWA, and their downstream interneurons, AIA and AIB (Fujiwara et al., 2016). Here we show that gcy-28 mutants have a defect in the germline-dependent regulation of olfactory preferences; gcy-28 mutant did not exhibit the change in chemotaxis regardless of whether germline cells proliferate normally. According to Ca2+ imaging analyses, the loss of germline cells diminished AIB calcium responses to diacetyl stimuli in wild-type animals, while, in the gcy-28 mutant, AIB responded to diacetyl normally even when the germline is lost. gcy-28 encodes a guanylyl cyclase with an extracellular ligand binding domain, and is expressed in many tissues including the nervous system. Cell-specific rescuing experiments suggested that GCY-28 acts at least partly in the AIA interneuron to mediate the developmental regulation of olfaction. GCY-28 tagged with gfp localized at gap junctions of AIA, which makes gap junctions with AWA and ASI neurons. Interestingly, blocking the gap junctions of AIA or of ASI in wild-type animals resulted in a defect in the germline-dependent chemotactic changes. We also found that silencing of ASI by expressing the leaky potassium channel unc-103(gf) caused a defect in the germline-dependent chemotactic changes. These results suggest that GCY-28 in AIA controls the germline-dependent chemotaxis by regulating ASI activity through the gap junctions. Further analyses will reveal the mechanism how the nervous system is adjusted by internal states such as sexual maturation.

Sun J et al. (2013) Exp Parasitol "Parasitism of secondary-stage juvenile of Heterodera glycines and four larva stages of Caenorhabditis elegans by Hirsutella spp."

Sun J, Xie H, Xiang M, Liu X, Qiu J

[Exp Parasitol, 2013]

The fungi Hirsutella rhossiliensis and Hirsutella minnesotensis generally parasitize only plant-parasitic nematodes in nature but parasitize the bacterivorous nematode Caenorhabditis elegans on agar plates. To establish a model system for studying the interaction between fungi and nematodes, we compared the parasitism of the first- to fourth-stage larvae (L1-L4) of C. elegans and second-stage juvenile (J2) of Heterodera glycines by twenty isolates of Hirsutella spp. Although parasitism differed substantially among isolates, both H. minnesotensis and H. rhossiliensis parasitized a higher percentage of H. glycines J2s than of C. elegans larvae. Parasitism of C. elegans L1s was correlated with parasitism of H. glycines J2s. Parasitism of C. elegans by H. rhossiliensis and H. minnesotensis was negatively correlated with larva size and motility, i.e., parasitism was higher for the younger stages. The C. elegans L1 is recommended for studying parasitism of nematodes by H. rhossiliensis and H. minnesotensis.

Fei YJ et al. (2000) J Biol Chem "A novel H(+)-coupled oligopeptide transporter (OPT3) from Caenorhabditis elegans with a predominant function as a H(+) channel and an exclusive expression in neurons."

Leibach FH, Romero MF, Krause MW, Huang W, Ganapathy V, Fei YJ, Liu JC

[J Biol Chem, 2000]

We have cloned and functionally characterized a novel, neuron-specific, H(+)-coupled oligopeptide transporter (OPT3) from Caenorhabditis elegans that functions predominantly as a H(+) channel. The opt3 gene is approximately 4.4 kilobases long and consists of 13 exons. The cDNA codes for a protein of 701 amino acids with 11 putative transmembrane domains. When expressed in mammalian cells and in Xenopus laevis oocytes, OPT3 cDNA induces H(+)-coupled transport of the dipeptide glycylsarcosine. Electrophysiological studies of the transport function of OPT3 in Xenopus oocytes show that this transporter, although capable of mediating H(+)-coupled peptide transport, functions predominantly as a H(+) channel. The H(+) channel activity of OPT3 is approximately 3-4-fold greater than the H(+)/peptide cotransport activity as determined by measurements of H(+) gradient-induced inward currents in the absence and presence of the dipeptide using the two-microelectrode voltage clamp technique. A downhill influx of H(+) was accompanied by a large intracellular acidification as evidenced from the changes in intracellular pH using an ion-selective microelectrode. The H(+) channel activity exhibits a K(0.5)(H) of 1.0 microM at a membrane potential of -50 mV. At the level of primary structure, OPT3 has moderate homology with OPT1 and OPT2, two other H(+)-coupled oligopeptide transporters previously cloned from C. elegans. Expression studies using the opt3::gfp fusion constructs in transgenic C. elegans demonstrate that opt3 gene is exclusively expressed in neurons. OPT3 may play an important physiological role as a pH balancer in the maintenance of H(+) homeostasis in C. elegans.

Imadzu H et al. (1994) Worm Breeder's Gazette "Two Tropomyosins Expressed in Body Wall and the Third Did In Pharynx of Caenorhabditis elegans"

Kagawa H, Sakube Y, Imadzu H

[Worm Breeder's Gazette, 1994]

TWO TROPOMYOSINS EXPRBSSBD IN BODY WALL AND THE THIRD DID IN PHARYNX OF CAENORHABDDITIS ELEGANS. H. Imadzu, Y. Sakube and H. gagawa. Department of Biology, Faculty of Science, Okayama University, Okayama, 700 Japan.

Wilson PA et al. (1982) Parasitology "Strongyloides ratti (homogonic): the time-course of early migration in the generalized host deduced from experiments in lactating rats."

Steven GE, Simpson NE, Wilson PA

[Parasitology, 1982]

Unsuckled mother rats given a 1 h suckling stimulus 3 h after subcutaneous injection of an exact dose of homogonic Strongyloides ratti allow fewer worms to develop in their intestines by day 9 than nulliparous rats (Wilson & Simpson, 1981). This effect is studied in more detail in terms of the length of time between weaning and stimulus (W leads to S) and injection and stimulus (I leads to S). It was observable with a W leads to S of 30 h but this and a period of 5 h were less effective than 24 h. With W leads to S constant at 24 h, significantly more worms developed in mothers when I leads to S was 24 h compared to 3 h and 10 h (P less than 0.005). The data, combined with those from nulliparous controls, are presented as a measure of the change with time of numbers of larvae in that compartment of the system which gives access to the stimulated mammary gland. It is argued that the particular compartment is the local lymph node draining the injection site and that the kinetics deduced are applicable to migration in the rat in general.

Miller DL et al. (2007) Proc Natl Acad Sci U S A "Hydrogen sulfide increases thermotolerance and lifespan in Caenorhabditis elegans."

Miller DL, Roth MB

[Proc Natl Acad Sci U S A, 2007]

Hydrogen sulfide (H(2)S) is naturally produced in animal cells. Exogenous H(2)S has been shown to effect physiological changes that improve the capacity of mammals to survive in otherwise lethal conditions. However, the mechanisms required for such alterations are unknown. We investigated the physiological response of Caenorhabditis elegans to H(2)S to elucidate the molecular mechanisms of H(2)S action. Here we show that nematodes exposed to H(2)S are apparently healthy and do not exhibit phenotypes consistent with metabolic inhibition. Instead, animals exposed to H(2)S are thermotolerant and long-lived. These phenotypes require SIR-2.1 activity but are genetically independent of the insulin signaling pathway, mitochondrial dysfunction, and caloric restriction. These studies suggest that SIR-2.1 activity may translate environmental change into physiological alterations that improve survival. It is interesting to consider the possibility that the mechanisms by which H(2)S increases thermotolerance and lifespan in nematodes are conserved and that studies using C. elegans may help explain the beneficial effects observed in mammals exposed to H(2)S.

Sakube Y et al. (1994) Worm Breeder's Gazette "The Genome Structure and Expression of Promoter/lacZ Fusion Genes of C. elegans Ryanodine Receptor"

Imadzu H, Sakube Y, Kagawa H

[Worm Breeder's Gazette, 1994]

The Genome Structure and Expression of Promoter/lacZ Fusion Genes of the C. elegans Ryanodine Receptor Y. Sakube, H. Imadzu and H. Kagawa, Laboratory of Molecular Biology, Faculty of Science, Okayama University, Okayama, 700 Japan C51918@JPNKUDPC

Valles P et al. (2006) Semin Nephrol "Kidney vacuolar H+ -ATPase: physiology and regulation."

Wysocki J, Batlle D, Lapointe MS, Valles P

[Semin Nephrol, 2006]

The vacuolar H(+)-ATPase is a multisubunit protein consisting of a peripheral catalytic domain (V(1)) that binds and hydrolyzes adenosine triphosphate (ATP) and provides energy to pump H(+) through the transmembrane domain (V(0)) against a large gradient. This proton-translocating vacuolar H(+)-ATPase is present in both intracellular compartments and the plasma membrane of eukaryotic cells. Mutations in genes encoding kidney intercalated cell-specific V(0) a4 and V(1) B1 subunits of the vacuolar H(+)-ATPase cause the syndrome of distal tubular renal acidosis. This review focuses on the function, regulation, and the role of vacuolar H(+)-ATPases in renal physiology. The localization of vacuolar H(+)-ATPases in the kidney, and their role in intracellular pH (pHi) regulation, transepithelial proton transport, and acid-base homeostasis are discussed.