Lake, Menesha et al. (2017) International Worm Meeting "Characterization of the transcriptional network that promotes gonadal development in Caenorhabditis elegans ."

Braun, Caleb J., Swann, Sellers, Lake, Menesha, Kreitz, Naden, Strickland, Kayman, Kroetz, Mary B.

[International Worm Meeting, 2017]

During embryogenesis, the C. elegans gonad originates as a primordium of cells consisting of two somatic gonadal cells that flank two germ line precursor cells. The gonadal primordium is morphologically identical in the two sexes. Midway through the first larval stage, the somatic gonadal cells divide and differentiate, and during the course of development they will ultimately form one of two dramatically different organs: either a single-armed testis in the male or two bilaterally symmetric ovotestes connected to a central uterus in the hermaphrodite. To help define genes responsible for promoting gonadal development, we identified transcripts enriched for expression in the developing somatic gonad compared to the whole animal using cell-specific RNA-seq (Kroetz and Zarkower, 2015). Additionally, transcripts that were expressed in a sex-biased manner in the gonad have also been identified. Sex-biased transcripts were defined as transcripts that were enriched in one sex of gonadal cells compared to the expression in the gonadal cells of the other sex. Of the more than 900 gonad-enriched transcripts, approximately 80 encode for proteins that are transcriptional regulators. Seventeen transcription factors are expressed in a male-biased manner, and nine transcription factors are expressed in a hermaphrodite-biased manner in the developing gonad. To better understand if and how these transcription factors are controlling expression of the gonad-enriched transcripts, we are characterizing the expression patterns of proteins whose transcripts show the strongest gonadal enrichment. We are using CRISPR-Cas to fuse GFP to the C-terminus of the endogenously expressed gonadal proteins. We then use loss-of-function mutations or RNAi against the sex-biased or gonad-enriched transcription factors to determine if the transcription factors are important for expression of the GFP-tagged genes. This work will better define the transcriptional networks controlling gonad development and give insights into how key genetic regulators promote sex-specific organogenesis.

Shih, Pei-Yin et al. (2019) International Worm Meeting "Extremophile nematodes from Mono Lake demonstrate adaptation to an arsenic-rich environment."

Sapir, Amir, Goetz, Elizabeth, Shih, Pei-Yin, Lee, James Siho, Sternberg, Paul, Badroos, Jean Marie, Shinya, Ryoji

[International Worm Meeting, 2019]

Extremophiles have much to reveal about the biology of resilience, yet their study has been limited by sampling difficulties and the shortage of lab-culturable extremophiles. The broad success and small size of nematodes make them advantageous for tackling these problems. We investigated Mono Lake (CA, USA), a basin that is arsenic-rich, alkaline, and hypersaline, for the presence of extremophile nematodes. Mono Lake was previously described to only contain microbes and two arthropod species. Here, we report the discovery of eight nematode species from the lake, including five new species. Phylogenetic and morphological analyses suggest that the nematodes originate from multiple colonization events, and that they cohabitate the lake with microbes and arthropods as microbe-grazers, parasites, and predators. One species, Auanema tufa n. sp., is culturable, and we found it to have an ovoviviparous life cycle (hatching of embryos inside the mother), a common and likely adaptive trait of extremophile nematodes. A. tufa is resistant to As(III) arsenite and As(V) arsenate-the primary forms of arsenic in the lake-and can survive prolonged exposure to 100,000-times the human lethal limit. A. tufa has higher arsenic resistance than Caenorhabditis elegans gain-of-function mutants of SKN-1/Nrf, the major arsenic response coordinator in C. elegans. Our findings expand the range of Mono Lake extremophiles, highlight nematodes for investigating extremophile biology, and provide a culturable organism for studying animal arsenic resistance.

Shih PY et al. (2019) Curr Biol "Newly Identified Nematodes from Mono Lake Exhibit Extreme Arsenic Resistance."

Shinya R, Sapir A, Kanzaki N, Shih PY, Goetz E, Pires-Dasilva A, Sternberg PW, Badroos JM, Lee JS

[Curr Biol, 2019]

Extremophiles have much to reveal about the biology of resilience, yet their study is limited by sampling and culturing difficulties [1-3]. The broad success and small size of nematodes make them advantageous for tackling these problems [4-6]. We investigated the arsenic-rich, alkaline, and hypersaline Mono Lake (CA, US) [7-9] for extremophile nematodes. Though Mono Lake has previously been described to contain only two animal species (brine shrimp and alkali flies) in its water and sediments [10], we report the discovery of eight nematode species from the lake, including microbe grazers, parasites, and predators. Thus, nematodes are the dominant animals of Mono Lake in species richness. Phylogenetic analysis suggests that the nematodes originated from multiple colonization events, which is striking, given the young history of extreme conditions at Mono Lake [7, 11]. One species, Auanema sp., is new, culturable, and survives 500 times the human lethal dose of arsenic. Comparisons to two non-extremophile sister species [12] reveal that arsenic resistance is a common feature of the genus and a preadaptive trait that likely allowed Auanema to inhabit Mono Lake. This preadaptation may be partly explained by a variant in the gene dbt-1 shared with some Caenorhabditiselegans natural populations and known to confer arsenic resistance [13]. Our findings expand Mono Lake's ecosystem from two known animal species to ten, and they provide a new system for studying arsenic resistance. The dominance of nematodes in Mono Lake and other extreme environments and our findings of preadaptation to arsenic raise the intriguing possibility that nematodes are widely pre-adapted to be extremophiles.

Hoss S et al. (2001) Freshwater Biology "Refractory dissolved organic matter can influence the reproduction of Caenorhabditis elegans (Nematoda)."

Bergtold M, Steinberg CE, Traunspurger W, Haitzer M, Hoss S

[Freshwater Biology, 2001]

1 . We investigated the effect of refractory dissolved organic matter (refractory DOM: fulvic acids (FAs) and ultrafiltrates (UFs)), isolated from five different sources, on the reproduction of the bacterivorous nematode Caenorhabditis elegans. Nematodes were exposed to DOM (0.5-64 mg L-1 dissolved organic carbon) during a whole life cycle (72 h). At the end of the test, the number of offspring per worm was determined. 2. We also studied the effect of refractory DOM on abundance, cell size, and activity of the bacteria (Escherichia coli) that were used as a food source for the nematodes, to assess possible indirect effects of DOM via the food organisms. 3. The effects of DOM on the reproduction of C. elegans varied, depending on the origin and concentration of DOM. FAs isolated from a soil leachate and from the effluent of a waste water plant, as well as UFs from a humic lake and from a marsh, stimulated the reproduction of C. elegans. FAs from ground water had no effect, while FAs from a humic lake inhibited the reproduction of the nematodes. All effects occurred at ecologically relevant DOM concentrations and showed clear dose-response relationships. 4. Neither bacterial abundance nor cell size were influenced by refractory DOM. Bacterial activity was unaffected by four types of DOM. Only FAs from the humic lake caused a significant decrease in bacterial activity over 72 h. 5. The negative effect of FAs from the humic lake on nematode reproduction may be a consequence of a lower bacterial activity in this treatment. The positive effects of refractory DOM, however, could not be related to bacterial parameters. Therefore, we assume that the DOM directly influenced the reproduction of C. elegans. We speculate that refractory DOM can potentially be an additional carbon source or a source of trace nutrients influencing the reproduction of C. elegans. Adsorption of refractory DOM on bacterial cells, serving as food for the nematodes, may have been an important factor for the availability of DOM for C. elegans.

Mlot C (1991) Science "A well-rounded worm."

Mlot C

[Science, 1991]

The millimeter-long roundworm Caenorhabditis elegans is amassing a sizable research following. As more and more people have joined teh confederation of research efforts loosely called the worm project (see Science, 15 June 1990, p. 1310), the community's biennial meeting has outgrown the traditional watering hole at Cold Spring Harbor. This year, the researchers moved inland for the Eighth International C. elegans Meeting, held June 1-5 on Lake Mendota at the University of Wisconsin, Madison. More than 500 "worm people" turned out to absorb progress reports on the sequencing of the C. elegans genome, the study of its developmental pathways-and some newer topics as well.

George GH et al. (1985) Am J Trop Med Hyg "The onchocercal nodule: interrelationship of adult worms and blood vessels."

Palmieri JR, Connor DH, George GH

[Am J Trop Med Hyg, 1985]

This study of onchocercal nodules reveals an intimate relationship between the cuticle of Onchocerca volvulus and the capillaries of the host. Perfusion of blood vessels with India ink and other special techniques reveal a proliferation of capillaries around the worms and communication between small vessels and the spaces around the worms. The space around the worm is continuous with the central fibrin lake. These findings, together with the fact that the worm's gut contains hemosiderin, suggest that the worm subverts the vascular reaction and causes within the nodule a controlled hemorrhage that serves the worm's nutritional needs. We believe this explains, in part, how worms survive in fibrous nodules for many years.

Jodie F Wren et al. (2005) International Worm Meeting "Environmental Genomics of Fluoranthene Exposure"

Stephen R Sturzenbaum, Jodie F Wren, A John Morgan, Peter K Hankard, Nick Redshaw, Suresh C Swain, Claus Svendsen, Martijs J Jonker, David J Spurgeon

[International Worm Meeting, 2005]

Benzo(j)Fluoranthene, is a 5-ring polycyclic aromatic hydrocarbon (PAH), known to occur as a product of plant biosynthesis, but also as a byproduct of incomplete combustion of organic material. Fluoranthene has been identified in cigarette smoke, char-broiled foods, drinking water, lake sediments and ambient air. It is thought to interact with DNA, cause heritable genetic disorders and has been associated with lung, intestinal and pharyngeal cancer. Information regarding the toxicity of fluoranthene in C.elegans still remains scarce, a shortfall we are aiming to redress. Using GE-31 (an embryonic lethal TS mutant) an elaborate toxicity test identified a dose dependant slippery pharynx phenotype and effects on specific demographic endpoints, such as brood size, volumetric growth and life span. Exploiting whole genome oligo array technology, we are currently exploring the stage-specific toxic effects of fluoranthene at a transcriptional level.

Mikus H et al. (2016) Biochem Biophys Res Commun "The nematode Caenorhabditis elegans survives subfreezing temperatures in an isochoric system."

Rubinsky B, Serban A, Miller A, Mikus H, Shapira M, Nastase G

[Biochem Biophys Res Commun, 2016]

This study is the first experimental evidence showing that a living multicellular organism, the nematode Caenorhabditis elegans, can survive subfreezing temperatures in an isochoric (constant volume) thermodynamic system, while immersed in a simple isotonic solution, without the addition of cryoprotectants. Some of the test conditions were more extreme than those found at the ice/water interface of the Antarctic subglacial Vostok lake. On earth, life takes place in an isobaric (constant pressure) environment. In isobaric systems, subfreezing temperature survival of organisms in nature and subfreezing temperature preservation of living material for biotechnology and medicine, is made possible by use of cryoprotective chemicals additives. Our theoretical thermodynamic studies suggested that in an isochoric system, living biological material could survive subfreezing temperatures, without any cryoprotective chemicals. By confirming the theoretical predictions, this paper suggests a new technology for subfreezing preservation of cells, organs and organisms of possible value for biotechnology and medicine as well as new possible mechanisms of living organism survival in nature.

Gui Z et al. (2020) Biochem Biophys Res Commun "Pseudomonas donghuensis HYS 7-hydroxytropolone contributes to pathogenicity toward Caenorhabditis elegans and is influenced by pantothenic acid"

Qin Y, Xie G, You J, Xie Z, Wu T, Gui Z

[Biochem Biophys Res Commun, 2020]

Pseudomonas donghuensis HYS, a bacterial strain identified from Donghu Lake, has tremendous toxicity toward Caenorhabditis elegans and is characterized by high 7-hydroxytropolone siderophore production. Here, the relationship between pathogenic siderophore production and pantothenic acid was evaluated. The pathogenicity of P. donghuensis HYS was illustrated using C. elegans as a host. Based on slow-killing assay findings, a 7-hydroxytropolone deficiency-causing mutation attenuated P. donghuensis HYS pathogenicity, which was restored by the addition of extracted 7-hydroxytropolone. Moreover, data from real-time qPCR analysis and characteristic absorption assays indicated that pantothenic acid deficiency repressed transcriptional levels of orf9, which further reduced 7-hydroxytropolone production. Furthermore, slow-killing assays indicated that panB and pantothenic acid affected the virulence of P. donghuensis. These results indicate that a 7-hydroxytropolone siderophore-producing strain is virulent toward C. elegans. Our findings demonstrate that pantothenic acid is associated with P. donghuensis siderophore production-related pathogenicity.

Mulcahy B et al. (2010) Invert Neurosci "Meeting report: 2010 Caenorhabditis elegans Neurobiology Meeting, University of Wisconsin, USA."

Mulcahy B, Ient B

[Invert Neurosci, 2010]

Against the backdrop of the scenic Lake Mendota, the C. elegans Neurobiology Meeting came to a head. Expertly organised by Brian Ackley and Bruce Bamber and hosted at the accommodating University of Wisconsin, the meeting brought together recent contributions from many of the major research groups working on the neurobiology of C. elegans. With seven keynote speakers, 57 verbal presentations and hundreds of posters, this exciting event spanned a fascinating 3days from 27 June to 30 June 2010. In keeping with the tradition of this conference, the event on the whole was spearheaded by young investigators from several research institutions. The meeting served to emphasise the gains enjoyed by taking advantage of the genetic tractability of the worm. A thread that ran through the meeting was the importance of integrating data across different levels of biological organisation to permit delineation of the physiology underpinning discrete behavioural states. Recent advances in optogenetics and microfluidics were at the forefront of refining these analyses. The presentations discussed in this meeting report are a selection which reflects this overarching theme.