A shortcut to identifying small molecule signals that regulate behavior and development in Caenorhabditis elegans

Small molecule metabolites play important roles in Caenorhabditis elegans biology, but effective approaches for identifying their chemical structures are lacking. Recent studies revealed that a family of glycosides, the ascarosides, differentially regulate C. elegans development and behavior. Low concentrations of ascarosides attract males and thus appear to be part of the C. elegans sex pheromone, whereas higher concentrations induce developmental arrest at the dauer stage, an alternative, nonaging larval stage. The ascarosides act synergistically, which presented challenges for their identification via traditional activity-guided fractionation. As a result the chemical characterization of the dauer and male attracting pheromones remained incomplete. Here, we describe the identification of several additional pheromone components by using a recently developed NMR-spectroscopic approach, differential analysis by 2D NMR spectroscopy (DANS), which simplifies linking small molecule metabolites with their biological function. DANS-based comparison of wild-type C. elegans and a signaling-deficient mutant, daf-22, enabled identification of 3 known and 4 previously undescribed ascarosides, including a compound that features a p-aminobenzoic acid subunit. Biological testing of synthetic samples of these compounds revealed additional evidence for synergy and provided insights into structure–activity relationships. Using a combination of the three most active ascarosides allowed full reconstitution of the male-attracting activity of wild-type pheromone extract. Our results highlight the efficacy of DANS as a method for identifying small-molecule metabolites and placing them within a specific genetic context. This study further supports the hypothesis that ascarosides represent a structurally diverse set of nematode signaling molecules regulating major life history traits

Nematophagous fungus Arthrobotrys oligospora mimics olfactory cues of sex and food to lure its nematode prey

To study the molecular basis for predator-prey coevolution, we investigated how Caenorhabditis elegans responds to the predatory fungus Arthrobotrys oligospora. C. elegans and other nematodes were attracted to volatile compounds produced by A. oligospora. Gas-chromatographic mass-spectral analyses of A. oligospora-derived volatile metabolites identified several odors mimicking food cues attractive to nematodes. One compound, methyl 3-methyl-2-butenoate (MMB) additionally triggered strong sex- and stage-specific attraction in several Caenorhabditis species. Furthermore, when MMB is present, it interferes with nematode mating, suggesting that MMB might mimic sex pheromone in Caenorhabditis species. Forward genetic screening suggests that multiple receptors are involved in sensing MMB. Response to fungal odors involves the olfactory neuron AWCs. Single-cell RNA-seq revealed the GPCRs expressed in AWC. We propose that A. oligospora likely evolved the means to use olfactory mimicry to attract its nematode prey through the olfactory neurons in C. elegans and related species

Use Of Deadly Force Authorized

The Driveabouts are documentations of journeys into the political, historic and geographic landscape. They take the form of large photolanguage installations that combine contemporary photographs with historic images and maps. The name Driveabout is a reference to walkabouts, the spiritual journeys of many traditional cultures. For these journeys I strap myself into a steel and glass wheeled vehicle, that consumes non-renewable resources and spews green house gases and acid rain components, and travel to places of political and historic significance. Photographs taken along the way illustrate contemporary evidences of connection to past and distant events and places, and murals (computer printouts and/ or color laser copies) ground the work. The photographs are printed to 8"x 10" and have the mile number (at which they were shot) and a descriptive text printed into the top of the image. The murals consist of maps, historic photos and historic texts; they tell the story, letting the viewer know why this is a place of significance.&nbsp; A relationship between these Driveabouts and the walkabouts of traditional cultures is that both are journeys of discovery. The Driveabouts are a personal search for a more thorough understanding of our culture's relationship to its political, historic and geographic environment. They are also meant to communicate the process of searching (and the results of that search) to the viewer. Their form is loosely based on a scientific model; this is meant to emphasize the investigative nature of the work and to exaggerate the commonly held misperception that photography is exclusively an artifact of objective truth. I would like the Driveabouts to look more like documentation than like high art. High culture is usually handed down from above, by the powerful galleries and museums and their wealthy benefactors. This elitist structure has disenfranchised the average person. The Driveabouts use a common language; maps and photographs are universal in our culture and the texts offer an additional anchor. My intent is to offer work that speaks in the language of the non-elite. I would like the viewer to reexamine the connections that we have to the past, and to be more aware of the evidences of this connection that we live with daily. It is important to me that these works are not seen as judgements from above. I am a part of the culture that I critique and self implication is intended. The Driveabouts will be considered a success if they ask more questions of the viewer than they answer, and the best response would be for the viewer to be stimulated into investigating further the questions raised by my work. &nbsp;</p

Rebuilding the Fortymile caribou herd: A model of cooperative management planning

We examined the public process used to develop the 1996&mdash;2001 Fortymile Caribou (Rangifer tarandus) Herd Management Plan adopted by state and federal management boards. The process differed from most government-supported planning processes because it was initiated by residents of Alaska and Yukon, and not by an agency. State, federal, and territorial agencies were asked to participate in and support development of a management plan that would include a broad range of interest groups. We describe the planning effort, issues addressed by the planning team that posed significant challenges during both the planning and implementation phases, and then identify unforeseen costs and benefits derived from the process. Critical decision points in plan development and implementation are discussed

Nuevo puente colgante sobre el Tigris, en Bagdad

This suspension bridge is the first of its type built in Irak. Its structure is mainly of steel, though the deck is a compound construction of steel and concrete. It has three spans: a central one of 168 m length, and two lateral ones, each 84 m long. There are also two approach spans, each of 23 m, which have been made necessary due to the weakness of the soil. This is also the reason why the abutments do not support the load on the cables, so that the structure is anchored to itself: to achieve this the foundations have been reinforced with steel. The cables consist of 37 chords, each having 91 cables, of 4.5 mm diameter each, and a permissible stress of 158 kg/mm². The piles are protected with screens of metal sheetpiling.<br><br>Este puente colgante es el primero de su tipo construido en Irak. Su estructura fundamental es de acero; y el tablero mixto, de acero y hormigón. Consta de tres tramos, uno central de 168 m de luz y dos laterales, de 84 m de luz cada uno, más dos accesos, de 23 m, que fue preciso construir debido a la poca resistencia del terreno. Esta es también la causa de que los estribos no soporten la tensión de los cables, y de que la estructura esté anclada en sí misma, para lo cual se reforzó la cimentación con armaduras de acero. Los cables están constituidos por 37 cordones, y cada cordón, por 91 alambres de 4,5 mm Ø y una resistencia de 158 kg/mm². Las pilas van protegidas con cortinas de tablestacas metálicas

Nematophagous fungus Arthrobotrys oligospora mimics olfactory cues of sex and food to lure its nematode prey

To study the molecular basis for predator-prey coevolution, we investigated how Caenorhabditis elegans responds to the predatory fungus Arthrobotrys oligospora. C. elegans and other nematodes were attracted to volatile compounds produced by A. oligospora. Gas-chromatographic mass-spectral analyses of A. oligospora-derived volatile metabolites identified several odors mimicking food cues attractive to nematodes. One compound, methyl 3-methyl-2-butenoate (MMB) additionally triggered strong sex- and stage-specific attraction in several Caenorhabditis species. Furthermore, when MMB is present, it interferes with nematode mating, suggesting that MMB might mimic sex pheromone in Caenorhabditis species. Forward genetic screening suggests that multiple receptors are involved in sensing MMB. Response to fungal odors involves the olfactory neuron AWCs. Single-cell RNA-seq revealed the GPCRs expressed in AWC. We propose that A. oligospora likely evolved the means to use olfactory mimicry to attract its nematode prey through the olfactory neurons in C. elegans and related species