Fang, Victoria et al. (2011) International Worm Meeting "Multiple Routes to Suppressing aph-1(zu147) Embryonic Lethality."

Goutte, Caroline, Fang, Victoria, Hale, Valerie

[International Worm Meeting, 2011]

aph-1 encodes one of the four essential components of the gamma secretase complex, which is essential for Notch signaling. aph-1 null mutations cause fully penetrant maternal-effect embryonic lethality and egg laying defect. The leaky aph-1(zu147) mutation does not compromise egg laying and causes a less severe defect in embryogenesis in which 1% of the embryos survive to adulthood. The aph-1(zu147) mutation introduces a stop codon 33 residues prematurely. We have found that this mutant mRNA is destabilized by nonsense-mediated mRNA (NMD) decay. Interrupting NMD with a smg mutation increases mRNA levels of aph-1(zu147), and allows for successful embryogenesis in virtually all embryos. This result suggests that it is the decreased levels of aph-1 activity that are the cause of failed Notch signaling in the embryos from aph-1(zu147) mutant hermaphrodites. We have identified two different extragenic suppressors of aph-1(zu147) that do not appear to act on mRNA levels, but may instead regulate protein stability through ubiquitin-mediated proteosomal degradation. One of the suppressors encodes a novel gene product that interacts with an E3 ubiquitin ligase, and the other may itself function as an E3 ubiquitin ligase. We do not yet know whether the relevant target protein of these suppressors is APH-1 itself, or other components of the Notch signaling pathway. To this end we have investigated the ability of these suppressors to influence Notch signaling in worms that have compromised Notch receptors or compromised LAG-1, the downstream transcritption effector of the Notch signaling pathway. At least one of the suppressors can influence GLP-1 activity in embryos as well as in gonads, but has no significant effect on LIN-12 function during vulval morphogenesis. Ubiquitin-mediated degradation of Notch receptor and presenilin have previously been demonstrated for the E3 ubiquitin ligase SEL-10, which itself was identified as a suppressor/enhancer of LIN-12 (Hubbard et al., 1997, Wu et al., 2001, Li et al, 2002). We have found that the sel-10(n1077) missense mutation (Jager et al, 2004) can partially suppress aph-1(zu147) embryonic lethality, suggesting that elevation of Notch and/or presenilin may overcome the aph-1(zu147) defect, or that SEL-10 E3 ubiquitin ligase might also target APH-1. We are investigating whether our two suppressor genes act in the same, or in distinct pathways as that of the SEL-10 E3 ubiquitin ligase to modulate embryonic Notch signaling.

Chalfie M et al. (1994) Science "Green fluorescent protein as a marker for gene expression."

Euskirchen G, Tu Y, Chalfie M, Prasher DC, Ward WW

[Science, 1994]

A complementary DNA for the Aequorea victoria green fluorescent protein (GFP) produces a fluorescent product when expressed in prokaryotic (Escherichia coli) or eukaryotic (Caenorhabditis elegans) cells. Because exogenous substrates and cofactors are not required for this fluorescence, GFP expression can be used to monitor gene expression and protein localization in living organisms.

Miller DM et al. (1999) Biotechniques "Two-color GFP expression system for C. elegans."

Desai NS, Piston DW, Hardin DC, Xu SQ, Miller DM, Fleenor J, Fire A, Patterson GH

[Biotechniques, 1999]

We describe the use of modified versions of the Aequora victoria green fluorescent protein (GFP) to simultaneously follow the expression and distribution of two different proteins in the nematode, Caenorhabditis elegans. A cyan-colored GFP derivative, designated CFP, contains amino acid (aa) substitutions Y66W, N146I, M153T and V163A relative to the original GFP sequence and is similar to the previously reported "W7" form. A yellow-shifted GFP derivative, designated YFP, contains aa substitutions S65G, V68A, S72A and T203Y and is similar to the previously described "I0C" variant. Coding regions for CFP and YFP were constructed in the context of a high-activity C. elegans expression system. Previously characterized promoters and localization signals have been used to express CFP and YFP in C. elegans. Filter sets designed to distinguish YFP and CFP fluorescence spectra allowed visualization of the two distinct forms of GFP in neurons and in muscle cells. A series of expression vectors carrying CFP and YFP have been constructed and are being made available to the scientific community.

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.

David Alan Wharton (2010) Evolutionary Biology of Caenorhabditis and Other Nematodes "Panagrolaimus davidi, an Antarctic nematode model for the survival of extreme environmental stress"

David Alan Wharton

[Evolutionary Biology of Caenorhabditis and Other Nematodes, 2010]

Nematodes are found in almost all environments, including those where they are often exposed to extreme environmental stress. Panagrolaimus davidi is an Antarctic nematode living associated with moss and algae in terrestrial habitats on the Victoria Land coast that are free of snow and ice for part of the year. It has to survive very variable thermal and hydric environments where liquid water and temperatures suitable for growth are only periodically available. P. davidi can survive complete water loss (anhydrobiosis) and is the only organism that has been shown to survive intracellular ice formation throughout its tissues. It has several cold tolerance strategies, including; freeze avoidance, cryoprotective dehydration, freezing tolerance and anhydrobiosis. The mechanisms involved may include the production of trehalose, ice active proteins and the control of ice nucleation. Do the different survival strategies of P. davidi represent the expression of different gene sets or does the production of stress-related compounds provide protection against a variety of environmental challenges? Other nematodes, including Caenorhabditis elegans, are not so resistant to desiccation and freezing. Comparing the genomes of P. davidi and C. elegans may thus highlight the adaptations that are necessary for the survival of extreme environmental stress.

Thomas BJ et al. (2019) PLoS One "CemOrange2 fusions facilitate multifluorophore subcellular imaging in C. elegans."

Cole FS, Silverman GA, Thomas BJ, Chou WYY, Wambach JA, Kim H, Buland JR, Jia H, Homayouni A, Moreno M, Luke CJ, Pak SC, Huang H, Wight IE, Dawson Z

[PLoS One, 2019]

Due to its ease of genetic manipulation and transparency, Caenorhabditis elegans (C. elegans) has become a preferred model system to study gene function by microscopy. The use of Aequorea victoria green fluorescent protein (GFP) fused to proteins or targeting sequences of interest, further expanded upon the utility of C. elegans by labeling subcellular structures, which enables following their disposition during development or in the presence of genetic mutations. Fluorescent proteins with excitation and emission spectra different from that of GFP accelerated the use of multifluorophore imaging in real time. We have expanded the repertoire of fluorescent proteins for use in C. elegans by developing a codon-optimized version of Orange2 (CemOrange2). Proteins or targeting motifs fused to CemOrange2 were distinguishable from the more common fluorophores used in the nematode; such as GFP, YFP, and mKate2. We generated a panel of CemOrange2 fusion constructs, and confirmed they were targeted to their correct subcellular addresses by colocalization with independent markers. To demonstrate the potential usefulness of this new panel of fluorescent protein markers, we showed that CemOrange2 fusion proteins could be used to: 1) monitor biological pathways, 2) multiplex with other fluorescent proteins to determine colocalization and 3) gain phenotypic knowledge of a human ABCA3 orthologue, ABT-4, trafficking variant in the C. elegans model organism.

Millan MI et al. (2009) Medicina (B Aires) "[The green fluorescent protein that glows in bioscience]."

Millan MI, Becu-Villalobos D

[Medicina (B Aires), 2009]

Green fluorescent protein (GFP) is a protein produced by the jellyfish Aequorea victoria, that emits bioluminescence in the green zone of the visible spectrum. The GFP gene has been cloned and is used in molecular biology as a marker. The three researchers that participated independently in elucidating the structure and function of this and its related proteins, Drs. Shimomura, Chalfie and Tsien were awarded the Nobel Prize in Chemistry 2008. Dr. Shimomura discovered and studied the properties of GFP. Using molecular biological techniques, Chalfie succeeded in introducing the GFP gene into the DNA of the small, almost transparent worm C. elegans, and initiated an era in which GFP would be used as a glowing marker for cellular biology. Finally, Dr.Tsien found precisely how GFP's structure produces the observed green fluorescence, and succeeded in modifying the structure to generate molecules that emit light at slightly different wavelengths, which gave tags of different colors. Fluorescent proteins are very versatile and are being used in many areas, such as microbiology, biotechnology, physiology, environmental engineering, development, etc. They can, for example, illuminate growing cancer tumours; show the development of Alzheimer's disease, or detect arsenic traces in water. Finding the key to how a marine organism produces light unexpectedly ended up providing researchers with a powerful array of tools with which to visualize cell biology in action.

Leifer, Andrew et al. (2011) International Worm Meeting "Shining light on behavior: An optogenetic dissection of neural circuits in freely behaving C. elegans."

Wen, Quan, Samuel, Aravinthan, Clark, Christopher, Leifer, Andrew, Fang-Yen, Christopher, Alkema, Mark

[International Worm Meeting, 2011]

Optogenetics provides a promising new platform for conducting behavioral neuroscience investigations in the nematode Caenorhabditis elegans. The ability to precisely manipulate neural activity in individual neurons in a moving worm allows one to pinpoint the contribution of individual neurons to animal behavior. Previously we developed a high-resolution optogenetic illumination system capable of delivering arbitrary light patterns to targeted cells in a freely moving C. elegans (Leifer and Fang-Yen et al, Nature Methods, 2011). The system, called CoLBeRT, uses a high speed camera and custom computer vision software to monitor the motion of an unrestrained worm. As the worm swims or crawls, the system instructs a digital micromirror device to reflect patterns of blue or green laser light onto specific cellular targets expressing Channelrhdopsin-2 or Halorhodopsin. The system has sufficient accuracy and resolution to stimulate individual mechanosensory neurons while a worm swims. Here we have expanded the CoLBeRT system's capabilities to dissect the motor circuit, mechanosensory circuit and investigate the roles of command interneurons. The system is now able to generate illumination patterns with arbitrary amplitude waveforms and we have adapted the system to work with microfluidic devices. We have used the system to differentiate models of wave propagation in the motor circuit, to study habituation in the mechanosensory circuit and to begin an exploration of the command interneurons. Preliminary evidence suggests that stimulation of the command interneuron AVA modulates the worm's backward velocity.

Yue-E H et al. (2016) Zhongguo Xue Xi Chong Bing Fang Zhi Za Zhi "[Meta regression analysis of five heavy metal biotoxicity effects onCaenorhabditis elegans]."

Yue-E H, Chao-Pin L, Nan Z

[Zhongguo Xue Xi Chong Bing Fang Zhi Za Zhi, 2016]

OBJECTIVE: To evaluate five heavy metal biotoxicity effects on Caenorhabditis elegans with Meta regression analysis. METHODS: The data were collected from the following electronic databases：PubMed, Web of Science, EBSCO, the Chinese Biomedical Database, Chinese National Knowledge Infrastructure, Wan Fang (Chinese) Databases and so on, and all updated through January 2004 to December 2014. A literature review was made on articles about Cd, Hg, Pb, As and Cr toxicity effects on C. elegans, and the data was extracted from figure information by Scan It software. A Meta regression model was built by stata12.0 software, using toxicity indices such as the dependent variables, and different metals, concentrations, exposure time, and development stages of C. elegans as independent variables. RESULTS:The study articles asociated with heavy metal biotoxicity effects on C. elegans were selected out, 10 studies of Cu, 12 studies of Cr, 12 studies of Pb, 12 studies of Cd, 3 studies of As and 14 studies of Hg. The mortality of toxicities of 5 heavy metals on C. elegans ranked Hg > Pb > Cr> Cd>As; the biotoxicity of the indexes of body size based on development, generational time based on reproductive toxicity, body bend frequencies, and head thrash frequencies based on neurotoxicity ranked Hg > Pb > Cr > Cd; the biotoxicity ranked Hg > Pb > Cr> Cd>As by LC50 indexes of toxicities of 5 heavy metals on C. elegans. The sensitivity analysis proved that the Meta regression model was reliable. CONCLUSIONS: The biotoxicities on C. elegans of Hg and Pb are stronger than Cr, Cd and As.

Conroy, Brian et al. (2013) International Worm Meeting "The neuronal basis of food choice behavior in Caenorhabditis elegans."

Morabe, Maria, Chambers, Melissa, Conroy, Brian, Macfarlane, Rachel, Haynes, Lillian, Glater, Elizabeth

[International Worm Meeting, 2013]

Caenorhabditis elegans uses chemosensation to distinguish among various species of bacteria, their major food source (Ha et al., 2010; Shtonda and Avery, 2006). Although the neurons required for the detection of specific food-odors have been well-defined (Bargmann, 2006), less is known about the sensory circuits underlying the discrimination among the mixtures of odors released by bacteria. We plan to examine the neural machinery underlying bacterial preference among a diverse set of bacterial species. Does bacterial choice use one common neuronal mechanism or a diversity of mechanisms depending on the bacteria? Do some bacterial choices involve a single sensory neuron and others involve multiple sensory neurons? To address these questions, we are testing the food preferences of C. elegans for bacteria found in their natural habitats (kindly provided by Marie-Anne Felix, Institut Jacques Monod, Paris, France). We have found that C. elegans strongly prefers the odors of Providencia sp., Alcaligenes sp., and Flavobacteria sp., to Escherichia coli HB101, a commonly used food source for C. elegans. We have identified that the olfactory neuron AWC is necessary for this preference. We intend to test whether other amphid sensory neurons are also necessary for bacterial preference. In the future we will extend our analysis to other bacterial species to determine the diversity of the underlying neuronal mechanisms. Bargmann, C.I. (2006). http://www.wormbook.org. Ha, H.I., Hendricks, M., Shen, Y., Gabel, C.V., Fang-Yen, C., Qin, Y., Colon-Ramos, D., Shen, K., Samuel, A.D., and Zhang, Y. (2010). Neuron 68, 1173-1186. Shtonda, B.B., and Avery, L. (2006). J Exp Biol 209, 89-102.