Steroid Hormone Pathways Coordinate Developmental Diapause and Olfactory Remodeling in Pristionchus pacificus

Genetics ◽  
2021 ◽  
Author(s):  
Heather R Carstensen ◽  
Reinard M Villalon ◽  
Navonil Banerjee ◽  
Elissa A Hallem ◽  
Ray L Hong
Keyword(s):  
Behavioral Plasticity ◽  
Steroid Hormone ◽  
Pristionchus Pacificus ◽  
C Elegans ◽  
Host Seeking ◽  
Seeking Behavior ◽  
Ectopic Activation ◽  
Odor Attraction ◽  
Dafachronic Acid ◽  
Dauer Larvae

Abstract Developmental and behavioral plasticity allow animals to prioritize alternative genetic programs during fluctuating environments. Behavioral remodeling may be acute in animals that interact with host organisms, since reproductive adults and the developmentally arrested larvae often have different ethological needs for chemical stimuli. To understand the genes that coordinate development and host-seeking behavior, we used the entomophilic nematode Pristionchus pacificus to characterize dauer-constitutive mutants (Daf-c) that inappropriately enter developmental diapause to become dauer larvae. We found two Daf-c loci with dauer-constitutive and cuticle exsheathment phenotypes that can be rescued by the feeding of Δ7-dafachronic acid, and that are dependent on the conserved canonical steroid hormone receptor Ppa-DAF-12. Specifically at one locus, deletions in the sole HydroxySteroid Dehydrogenase (HSD) in P. pacificus resulted in Daf-c phenotypes. Ppa-hsd-2 is expressed in the canal neurons (CAN) and excretory cells whose homologous cells in C. elegans are not known to be involved in the dauer decision. While in wildtype only dauer larvae are attracted to host odors, hsd-2 mutant adults show enhanced attraction to the host beetle pheromone, along with ectopic activation of a marker for putative olfactory neurons, Ppa-odr-3. Surprisingly, this enhanced odor attraction acts independently of the Δ7-DA/DAF-12 module, suggesting that Ppa-HSD-2 may be responsible for several steroid hormone products involved in coordinating the dauer decision and host-seeking behavior in P. pacificus.

scholarly journals The Regulation of Developmental Diapause is Coordinated with Molting and Olfaction

2020 ◽  
Author(s):  
Heather R. Carstensen ◽  
Reinard M. Villalon ◽  
Johnny Vertiz ◽  
Navonil Banerjee ◽  
Elissa A. Hallem ◽  
...  
Keyword(s):  
Hormone Receptor ◽  
Behavioral Plasticity ◽  
Neuronal Development ◽  
Steroid Hormone ◽  
Dispersal Ability ◽  
Parasitic Nematodes ◽  
Steroid Hormone Receptor ◽  
Steroid Synthesis ◽  
Pristionchus Pacificus ◽  
Dauer Larvae

AbstractDevelopmental and behavioral plasticity allow animals to prioritize alternative genetic programs during fluctuating environments. Behavioral remodeling may be acute in animals that interact with host organisms, since reproductive adults and the developmentally arrested larvae often have different ethological needs for chemical stimuli. To understand the genes that coordinate development and behavior, we used the nematode model Pristionchus pacificus to characterize mutants that inappropriately enter developmental diapause to become dauer larvae (Daf-c). We found several key olfactory differences between P. pacificus and C. elegans Daf-c dauers. In addition, the two P. pacificus Daf-c alleles disrupt steroid synthesis required for proper regulation of the conserved canonical steroid hormone receptor DAF-12, whose dauer-constitutive and cuticle exsheathment phenotypes can be rescued by the feeding of Δ7-dafachronic acid. One allele, csu60, has a deletion in the sole HydroxySteroid Dehydrogenase (HSD) in P. pacificus. Both hsd-2(csu60) adults and dauers show enhanced attraction to a beetle pheromone, possibly due to the heterochronic activation of dauer-specific neuronal development in the adults. Surprisingly, this enhanced odor attraction acts independently of daf-12, revealing unexpected targets of steroid hormones regulating ecdysis and olfaction in P. pacificus.Author SummaryThe remarkable evolutionary success of nematodes can be attributed to their dispersal ability as stress-resistant dauer larvae and the equivalent parasitic infective larvae. The decision to enter dauer development is regulated by a conserved steroid hormone receptor that receives multiple external and internal cues, though the extent in which these cues also coordinate other physiological and behavioral processes is not well understood in divergent species. We used the insect-associated nematode Pristionchus pacificus to genetically dissect two mutants that form dauers inappropriately, and found that one mutation in a steroidogenic enzyme, Ppa-hsd-2, is predicted to abolish the biosynthesis of the hormones needed to negatively regulate dauer entry when food is available. Unexpectedly, Ppa-HSD-2 is also required to properly complete the dauer larval molt, known as exsheathment, as well as to confer differences in adult versus dauer larvae chemotaxis behavior towards a host pheromone. Given that dauers are the host-seeking stage of parasitic nematodes, hormonal disruption represents a tenable target for biological control.

scholarly journals UHPLC-IM-Q-ToFMS analysis of maradolipids, found exclusively in Caenorhabditis elegans dauer larvae

2021 ◽  
Vol 413 (8) ◽  
pp. 2091-2102
Author(s):  
Michael Witting ◽  
Ulrike Schmidt ◽  
Hans-Joachim Knölker
Keyword(s):  
Caenorhabditis Elegans ◽  
Developmental Stage ◽  
Ion Mobility ◽  
Environmental Conditions ◽  
Multidimensional Data ◽  
Specific Class ◽  
Lipid Profiling ◽  
C Elegans ◽  
Tandem Mass Spectrometric ◽  
Dauer Larvae

AbstractLipid identification is one of the current bottlenecks in lipidomics and lipid profiling, especially for novel lipid classes, and requires multidimensional data for correct annotation. We used the combination of chromatographic and ion mobility separation together with data-independent acquisition (DIA) of tandem mass spectrometric data for the analysis of lipids in the biomedical model organism Caenorhabditis elegans. C. elegans reacts to harsh environmental conditions by interrupting its normal life cycle and entering an alternative developmental stage called dauer stage. Dauer larvae show distinct changes in metabolism and morphology to survive unfavorable environmental conditions and are able to survive for a long time without feeding. Only at this developmental stage, dauer larvae produce a specific class of glycolipids called maradolipids. We performed an analysis of maradolipids using ultrahigh performance liquid chromatography-ion mobility spectrometry-quadrupole-time of flight-mass spectrometry (UHPLC-IM-Q-ToFMS) using drift tube ion mobility to showcase how the integration of retention times, collisional cross sections, and DIA fragmentation data can be used for lipid identification. The obtained results show that combination of UHPLC and IM separation together with DIA represents a valuable tool for initial lipid identification. Using this analytical tool, a total of 45 marado- and lysomaradolipids have been putatively identified and 10 confirmed by authentic standards directly from C. elegans dauer larvae lipid extracts without the further need for further purification of glycolipids. Furthermore, we putatively identified two isomers of a lysomaradolipid not known so far. Graphical abstract

scholarly journals Influence of pyrethroïd-treated bed net on host seeking behavior of Anopheles gambiae s.s. carrying the kdr allele

PLoS ONE ◽  
2017 ◽  
Vol 12 (7) ◽  
pp. e0164518 ◽  
Author(s):  
Angélique Porciani ◽  
Malal Diop ◽  
Nicolas Moiroux ◽  
Tatiana Kadoke-Lambi ◽  
Anna Cohuet ◽  
...  
Keyword(s):  
Anopheles Gambiae ◽  
Bed Net ◽  
Anopheles Gambiae S.S ◽  
Host Seeking ◽  
Seeking Behavior

scholarly journals Neuropeptides and Behaviors: How Small Peptides Regulate Nervous System Function and Behavioral Outputs

2021 ◽  
Vol 14 ◽  
Author(s):  
Umer Saleem Bhat ◽  
Navneet Shahi ◽  
Siju Surendran ◽  
Kavita Babu
Keyword(s):  
Nervous System ◽  
Behavioral Plasticity ◽  
Environmental Changes ◽  
Sensory Information ◽  
Synaptic Activity ◽  
Small Peptides ◽  
C Elegans ◽  
Wide Range ◽  
Nervous System Function ◽  
Insight Into

One of the reasons that most multicellular animals survive and thrive is because of the adaptable and plastic nature of their nervous systems. For an organism to survive, it is essential for the animal to respond and adapt to environmental changes. This is achieved by sensing external cues and translating them into behaviors through changes in synaptic activity. The nervous system plays a crucial role in constantly evaluating environmental cues and allowing for behavioral plasticity in the organism. Multiple neurotransmitters and neuropeptides have been implicated as key players for integrating sensory information to produce the desired output. Because of its simple nervous system and well-established neuronal connectome, C. elegans acts as an excellent model to understand the mechanisms underlying behavioral plasticity. Here, we critically review how neuropeptides modulate a wide range of behaviors by allowing for changes in neuronal and synaptic signaling. This review will have a specific focus on feeding, mating, sleep, addiction, learning and locomotory behaviors in C. elegans. With a view to understand evolutionary relationships, we explore the functions and associated pathophysiology of C. elegans neuropeptides that are conserved across different phyla. Further, we discuss the mechanisms of neuropeptidergic signaling and how these signals are regulated in different behaviors. Finally, we attempt to provide insight into developing potential therapeutics for neuropeptide-related disorders.

Study on host-seeking behavior and chemotaxis of entomopathogenic nematodes using Pluronic F-127 gel

2019 ◽  
Vol 161 ◽  
pp. 54-60 ◽  
Author(s):  
Chunjie Li ◽  
Xianhong Zhou ◽  
Edwin E. Lewis ◽  
Yi Yu ◽  
Congli Wang
Keyword(s):  
Entomopathogenic Nematodes ◽  
Host Seeking ◽  
Seeking Behavior

scholarly journals Dehydrated Caenorhabditis elegans Stocks Are Resistant to Multiple Freeze-Thaw Cycles

2020 ◽  
Vol 10 (12) ◽  
pp. 4505-4512
Author(s):  
Patrick D. McClanahan ◽  
Richard J. McCloskey ◽  
Melanie Ng Tung Hing ◽  
David M. Raizen ◽  
Christopher Fang-Yen
Keyword(s):  
Caenorhabditis Elegans ◽  
Freeze Thaw ◽  
C Elegans ◽  
Link Type ◽  
Defective Mutant ◽  
Genetic Stocks ◽  
Dauer Larvae

Ultracold preservation is widely used for storage of genetic stocks of Caenorhabditis elegans. Current cryopreservation protocols are vulnerable to refrigeration failures, which can result in the loss of stock viability due to damage during re-freezing. Here we present a method for preserving worms in a dehydrated and frozen form that retains viability after multiple freeze-thaw cycles. After dehydration in the presence of trehalose or glycerol, C. elegans stocks can be frozen and thawed multiple times while maintaining viability. While both dauer and non-dauer larvae survive desiccation and freezing, the dauer defective mutant daf-16 does not survive desiccation. Our technique is useful for storing stocks in a manner robust to freezer failures, and potentially for shipping strains between laboratories.

scholarly journals C. elegans possess a general program to enter cryptobiosis that allows dauer larvae to survive different kinds of abiotic stress

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Vamshidhar R. Gade ◽  
Sofia Traikov ◽  
Jana Oertel ◽  
Karim Fahmy ◽  
Teymuras V. Kurzchalia
Keyword(s):  
Abiotic Stress ◽  
C Elegans ◽  
General Program ◽  
Dauer Larvae

scholarly journals Effect of Dinotefuran, Permethrin, and Pyriproxyfen (Vectra® 3D) on the Foraging and Blood-Feeding Behaviors of Aedes albopictus Using Laboratory Rodent Model

Insects ◽  
2020 ◽  
Vol 11 (8) ◽  
pp. 507
Author(s):  
Younes Laidoudi ◽  
Djamel Tahir ◽  
Hacène Medkour ◽  
Marie Varloud ◽  
Oleg Mediannikov ◽  
...  
Keyword(s):  
Aedes Albopictus ◽  
Selection Index ◽  
Exposure Period ◽  
Blood Feeding ◽  
Feeding Behaviors ◽  
Host Seeking ◽  
Seeking Behavior ◽  
Feeding Effect ◽  
Rats And Mice ◽  
And Control

Dinotefuran-Permethrin-Pyriproxyfen (DPP) is used to kill and repel mosquitoes from dogs. However, the influence of the product on the host-seeking behavior of mosquitoes remains unknown. The interference of DPP with the host selection of unfed female Aedes albopictus was investigated. A total of 18 animals (9 mice and 9 rats) were divided into three groups of six animals each. DU: DPP treated rats (n = 3) with untreated mice (n = 3), UD: DPP treated mice (n = 3) with untreated rats (n = 3) and control UU: untreated mice (n = 3) and untreated rats (n = 3). In each group, the rats and mice were placed 30 cm apart. After sedation, the animals in each group were exposed twice (Day 1 and Day 7 post-treatment) for one hour to 71 ± 3 female mosquitoes. Mosquitoes were categorized after the 2-h post-exposure period as dead or alive. Blood-meal origin was determined from mosquitoes using a newly customized duplex qPCR. The highest values of forage ratio (1.36 ≥ wi ≤ 1.88) and selection index (0.63 ≥ Bi ≤ 0.94) for rat hosts indicates a preference of mosquitoes for this species as compared to mice when co-housed during the exposure. The mosquitoes only seldom fed on mice, even in the untreated group. The anti-feeding effect of DPP was therefore only assessed on rat’s hosts. The results showed that DPP, when directly applied on rats, provided a direct protection of 82% and 61% on Day 1 and Day 7, respectively, while when applied on mice hosts (UD), the DPP provided an indirect protection of 21% and 10% on Day 1 and Day 7, respectively. The results showed also that DPP, when applied on rats, provided a direct protection against Ae. albopictus bites. This effect did not result in increased exposure of the untreated host placed in the same cage at a distance of 30 cm.

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