Liu R et al. (2011) J Pept Sci "Two antimicrobial and nematicidal peptides derived from sequences encoded Picea sitchensis."

Liu R, You D, Chen M, Mu L, Lai R, Yan T, Li J, Wei L, Liu H, Zhang K

[J Pept Sci, 2011]

Two antimicrobial peptides (piceain 1 and 2) derived from sequences encoded Picea sitchensis are identified. Their amino acid sequences are KSLRPRCWIKIKFRCKSLKF and RPRCWIKIKFRCKSLKF, respectively. One intra-molecular disulfide bridge is formed by these two half-cysteines in both piceain 1 and 2. Antimicrobial activities of synthesized piceains against several kinds of microorganisms were tested. They showed antimicrobial activities against Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, and fungus Candida albicans but little antimicrobial activity against Bacillus subtilis. The results of nematicidal test showed they exerted strong nematicidal activities against Caenorhabditis elegans, following exposure for 5 h at concentrations as low as 10 g/ml. They had weak hemolytic abilities against human and rabbit red cells. At the concentration of 250 g/ml, they induced red cell hemolysis of less than 5%. Circular dichroism spectra of the two antimicrobial peptides were investigated in several solutions. Their main secondary structure components are -sheet and random. The current work provides a novel family of antimicrobial and nematicidal peptides with unique disulfided loop containing nine amino acid residues.

Kaplan HS et al. (2018) Neuron "Sensorimotor Integration for Decision Making: How the Worm Steers."

Zimmer M, Kaplan HS

[Neuron, 2018]

Animals' movements actively shape their perception and subsequent decision making. In this issue of Neuron, Liu etal. (2018) show how C.elegans nematodes steer toward an odorant: a dedicated interneuron class integrates oscillatory olfactory signals, generated by head swings, with corollary discharge motor signals.

Ali L et al. (2020) J Cell Biol "Mitochondrial translation, dynamics, and lysosomes combine to extend lifespan."

Ali L, Haynes CM

[J Cell Biol, 2020]

In this issue, Liu et al. (2019. J. Cell. Biol.https://doi.org/10.1083/jcb.201907067) find that the inhibition of mitochondrial ribosomes in combination with impaired mitochondrial fission or fusion increases C. elegans lifespan by activating the transcription factor HLH-30, which promotes lysosomal biogenesis.

Rahmani, Shapour et al. (2021) MicroPubl Biol

Tuck, Simon, Rahmani, Shapour

[MicroPubl Biol, 2021]

C. elegans males that have come into close proximity of hermaphrodites initiate copulatory behavior comprising at least five different steps termed response, turning, location of vulva, spicule insertion and sperm transfer (Loer and Kenyon 1993, Liu and Sternberg 1995, Chute and Srinivasan 2014). Mutations specifically affecting different steps have been isolated and characterized (Barr and Sternberg 1999, Hajdu-Cronin et al. 2017, Liu et al. 2017). However, our understanding of the molecular mechanisms acting in the neurons controlling copulation is far from complete. During the response step, males that have sensed the presence of a hermaphrodite move backwards in such a way that the males tail fan glides along the surface of the hermaphrodite until the tail reaches the vulva (or head or tail) (Loer and Kenyon 1993, Liu and Sternberg 1995, Sherlekar and Lints 2014). Response behavior is regulated by ciliated neurons in the tail whose dendrites lie in sensory rays within the fan (Liu and Sternberg 1995). If a male reaches the end of the hermaphrodite without having found the vulva, it executes a turn during which the tail bends tightly ventrally so that contact is established between the ventral surface of the fan and the other side of the intended mate (Loer and Kenyon 1993, Liu and Sternberg 1995). The ability to execute turns efficiently is dependent upon serotonergic neurons in the posterior ventral nerve cord (the CP neurons) and on their ability to produce serotonin (Loer and Kenyon 1993, Carnell et al. 2005). Serotonin stimulates the diagonal muscles in the tail to induce curling ventrally by stimulating a serotonin receptor, SER-1 (Loer and Kenyon 1993, Carnell et al. 2005). However, how serotonin affects diagonal muscles and ventral turning is not fully understood.

Liu H et al. (2018) Philos Trans R Soc Lond B Biol Sci "Functional connectomics from neural dynamics: probabilistic graphical models for neuronal network of Caenorhabditis elegans."

Shlizerman E, Kim J, Liu H

[Philos Trans R Soc Lond B Biol Sci, 2018]

We propose an approach to represent neuronal network dynamics as a probabilistic graphical model (PGM). To construct the PGM, we collect time series of neuronal responses produced by the neuronal network and use singular value decomposition to obtain a low-dimensional projection of the time-series data. We then extract dominant patterns from the projections to get pairwise dependency information and create a graphical model for the full network. The outcome model is a functional connectome that captures how stimuli propagate through the network and thus represents causal dependencies between neurons and stimuli. We apply our methodology to a model of the <i>Caenorhabditis elegans</i> somatic nervous system to validate and show an example of our approach. The structure and dynamics of the <i>C. elegans</i> nervous system are well studied and a model that generates neuronal responses is available. The resulting PGM enables us to obtain and verify underlying neuronal pathways for known behavioural scenarios and detect possible pathways for novel scenarios.This article is part of a discussion meeting issue 'Connectome to behaviour: modelling <i>C. elegans</i> at cellular resolution'.

Galindo-Malagn XA et al. (2022) Zootaxa "New species, synonymies and records in the genus Rhagovelia Mayr, 1865 (Hemiptera: Heteroptera: Veliidae) from Colombia."

Moreira FFF, Morales I, Mondragn-F SP, Galindo-Malagn XA

[Zootaxa, 2022]

Rhagovelia medinae sp. nov., of the hambletoni group (angustipes complex), and R. utria sp. nov., of the hirtipes group (robusta complex), are described, illustrated, and compared with similar congeners. Based on the examination of type specimens, six new synonymies are proposed: R. elegans Uhler, 1894 = R. pediformis Padilla-Gil, 2010, syn. nov.; R. cauca Polhemus, 1997 = R. azulita Padilla-Gil, 2009, syn. nov., R. huila Padilla-Gil, 2009, syn. nov., R. oporapa Padilla-Gil, 2009, syn. nov, R. quilichaensis Padilla-Gil, 2011, syn. nov.; and R. gaigei, Drake Hussey, 1947 = R. victoria Padilla-Gil, 2012 syn. nov. The first record from Colombia is presented for R. trailii (White, 1879), and the distributions of the following species are extended in the country: R. cali Polhemus, 1997, R. castanea Gould, 1931, R. cauca Polhemus, 1997, R. gaigei Drake Hussey, 1957, R. elegans Uhler, 1894, R. femoralis Champion, 1898, R. malkini Polhemus, 1997, R. perija Polhemus, 1997, R. sinuata Gould, 1931, R. venezuelana Polhemus, 1997, R. williamsi Gould, 1931, and R. zeteki Drake, 1953.

Liu J et al. (1996) Science "Interaction between a putative mechanosensory membrane channel and a collagen."

Schrank B, Waterston RH, Liu J

[Science, 1996]

The degenerin family of proteins in Caenorhabditis elegans is homologous to subunits of the mammalian amiloride-sensitive epithelial sodium channels. Mutations in nematode degenerins cause cell death, probably because of defects in channel function. Genetic evidence was obtained that the unc-105 gene product represents a degenerin homolog affecting C. elegans muscles and that this putative channel interacts with type IV collagen in the extracellular matrix underlying the muscle cell. This interaction may serve as a mechanism of stretch-activated muscle contraction, and this system could provide a molecular model for the activation of mechanosensitive ion channels.AD - Department of Genetics, Washington University School of Medicine, St. Louis, MO 63110, USA.FAU - Liu, JAU - Liu JFAU - Schrank, BAU - Schrank BFAU - Waterston, R HAU - Waterston RHLA - engSI - GENBANK/J04694SI - GENBANK/M23704SI - GENBANK/M67507SI - GENBANK/U07224SI - GENBANK/U07888SI - GENBANK/U22327SI - GENBANK/X56979SI - GENBANK/X76730SI - GENBANK/Y00706ID - GM23883/GM/NIGMSPT - Journal ArticleCY - UNITED STATESTA - ScienceJID - 0404511RN - 0 (Helminth Proteins)RN - 0 (Sodium Channels)RN - 0 (Unc-105 protein)RN - 9007-34-5 (Collagen)SB - IMSB - S

Dong B et al. (2007) J Biol Chem "Ca(2+)/calmodulin directly interacts with the pleckstrin homology domain of AKT1."

Dong B, Valencia CA, Liu R

[J Biol Chem, 2007]

AKT kinase, also known as protein kinase B, is a key regulator of cell growth, proliferation and metabolism. The activation of the AKT signaling pathway is one of the most frequent molecular alterations in a wide variety of human cancers. Dickson and coworkers recently observed that Ca2+/calmodulin (Ca2+/CaM) may be a common regulator of AKT1 activation (1). In our efforts to scan the mRNA-displayed proteome libraries for Ca2+/CaM-binding proteins, we found that both human and C. elegans AKT1 kinases bound to CaM in a Ca2+-dependent manner (2,3). Here we demonstrated that Ca2+/CaM and human AKT1 were efficiently co-immunoprecipitated and their interaction was direct rather than mediated by other proteins. The binding is in part attributed to the first 42 residues of the PH domain, a region that is critical for the recognition of its lipid ligands. The PH domain of human AKT1 can disrupt the complex of the full-length AKT1 with Ca2+/CaM. In addition, Ca2+/CaM competes with PtdIns(3,4,5)P3 for interaction with the PH domain of human AKT1. Our findings suggest that Ca2+/CaM is directly involved in regulating the functions of AKT1, presumably by releasing the activated AKT1 from the plasma membrane and/or prohibiting it from re-association with phosphoinostides on plasma membrane.

Lu WX et al. (1990) J Biol Chem "Cloning, structure, and expression of the gene for a novel regulatory subunit of cAMP-dependent protein kinase in Caenorhabditis elegans."

Bagchi S, Lu WX, Rubin CS, Gross RE

[J Biol Chem, 1990]

The nematode Caenorhabditis elegans (C. elegans) expresses the regulatory subunit (R) of cAMP-dependent protein kinase at a level similar to the levels determined for R subunits in mammalian tissues. Approximately 60% of the C. elegans cAMP-binding protein is tightly associated with particulate structures by noncovalent interactions. Ionic detergents or 7 M urea solubilize particulate R. Solubilized and cytosolic R subunits have apparent Mr values of 52,000 and pI values of 5.5. cDNA and genomic DNA encoding a unique C. elegans R subunit were cloned and sequenced. The derived amino acid sequence contains 375 residues; carboxyl-terminal residues 145-375 are 69% identical with mammalian RI. However, residues 44-145 are markedly divergent from the corresponding regions of all other R sequences. This region might provide sufficient structural diversity to adapt a single R subunit for multiple functional roles in C. elegans. Antibodies directed against two epitopes in the deduced amino acid sequence of C. elegans R avidly bound nematode cytosolic and particulate R subunits on Western blots and precipitated dissociated R subunits and R2C2 complexes from solution. Immunofluorescence analysis revealed that the tip of the head, which contains chemosensory and mechanosensory neurons, and the pharyngeal nerve ring were enriched in R. The R subunit concentration is low during early embryogenesis in C. elegans. A sharp increase (approximately 6-fold) in R content begins several hours before the nematodes hatch and peaks during the first larval stage. Developmental regulation of R expression occurs at translational and/or post-translational levels. The 8-kilobase pair C. elegans R gene is divided into 8 exons by introns ranging from 46 to 4300 base pairs. The 5'-flanking region has no TATA box and contains preferred and minor transcription start sites.

Kimura KD et al. (1997) Science "daf-2, an insulin receptor-like gene that regulates longevity and diapause in Caenorhabditis elegans."

Liu YX, Kimura KD, Ruvkun GB, Tissenbaum HA

[Science, 1997]

A C. elegans neurosecretory signaling system regulates whether animals enter the reproductive life cycle or arrest development at the long-lived dauer diapause stage. daf-2, a key gene in the genetic pathway that mediates this endocrine signaling, encodes an insulin receptor family member. Decreases in DAF-2 signaling induce metabolic and developmental changes, as in mammalian metabolic control by the insulin receptor. Decreased DAF-2 signaling also causes an increase in life-span. Life-span regulation by insulin-like metabolic control is analogous to mammalian longevity enhancement induced by caloric restriction, suggesting a general link between metabolism, diapause, and longevity.AD - Department of Molecular Biology, Massachusetts General Hospital, Boston, MA 02114, USA.FAU - Kimura, K DAU - Kimura KDFAU - Tissenbaum, H AAU - Tissenbaum HAFAU - Liu, YAU - Liu YFAU - Ruvkun, GAU - Ruvkun GLA - engSI - GENBANK/AF012437ID - RO1AG14161/AG/NIAPT - Journal ArticleCY - UNITED STATESTA - ScienceJID - 0404511RN - 0 (DAF-2 protein)RN - 0 (Phosphatidylinositol Phosphates)RN - 0 (insulin receptor-related receptor)RN - 0 (phosphatidylinositol 3,4,5-triphosphate)RN - 11061-68-0 (Insulin)RN - 50-99-7 (Glucose)RN - EC 2.7.1 (Phosphotransferases (Alcohol Group Acceptor))RN - EC 2.7.1.137 (1-Phosphatidylinositol 3-Kinase)RN - EC 2.7.11.- (Receptor, IGF Type 1)RN - EC 2.7.11.- (Receptor, Insulin)SB - IM