Genome-wide screen for genes involved in Caenorhabditis elegans developmentally timed sleep

In Caenorhabditis elegans, Notch signaling regulates developmentally timed sleep during the transition from L4 larval stage to adulthood (L4/A) . To identify core sleep pathways and to find genes acting downstream of Notch signaling, we undertook the first genome-wide, classical genetic screen focused on C. elegans developmentally timed sleep. To increase screen efficiency, we first looked for mutations that suppressed inappropriate anachronistic sleep in adult hsp::osm-11 animals overexpressing the Notch coligand OSM-11 after heat shock. We retained suppressor lines that also had defects in L4/A developmentally timed sleep, without heat shock overexpression of the Notch coligand. Sixteen suppressor lines with defects in developmentally timed sleep were identified. One line carried a new allele of goa-1; loss of GOA-1 Gαo decreased C. elegans sleep. Another line carried a new allele of gpb-2, encoding a Gβ5 protein; Gβ5 proteins have not been previously implicated in sleep. In other scenarios, Gβ5 GPB-2 acts with regulators of G protein signaling (RGS proteins) EAT-16 and EGL-10 to terminate either EGL-30 Gαq signaling or GOA-1 Gαo signaling, respectively. We found that loss of Gβ5 GPB-2 or RGS EAT-16 decreased L4/A sleep. By contrast, EGL-10 loss had no impact. Instead, loss of RGS-1 and RGS-2 increased sleep. Combined, our results suggest that, in the context of L4/A sleep, GPB-2 predominantly acts with EAT-16 RGS to inhibit EGL-30 Gαq signaling. These results confirm the importance of G protein signaling in sleep and demonstrate that these core sleep pathways function genetically downstream of the Notch signaling events promoting sleep

Normal sleep bouts are not essential for C. elegans survival and FoxO is important for compensatory changes in sleep

Additional file 6: Decreased lag-2 function does not slow vulval development. The progeny of wild type and lag-2(q420) animals raised at 25.5 °C were selected at the L4 stage, prior to lethargus entry. Vulval eversion was scored after 3 h; the percentage of animals completing vulval eversion was recorded. Significance was assessed by student’s two-tailed t-test p value < 0.5; error bars represents SEM from 3 trials. Total number of animals: wild type n = 45 and lag-2(q420) n = 42

Use of Gastric Bypass Surgery for the Treatment of Type 2 Diabetes Mellitus

Over the past decade, the incidence of type 2 diabetes mellitus (T2DM) has increased significantly. Evidence has shown that a clear association exists between obesity and diabetes development. This association has inspired researchers to explore bariatric surgery as an option for diabetes management and possible disease reversal. Improvement of T2DM using Roux-En-Y gastric bypass (RYGB) is thought to result from from a combination of weight loss, decreased caloric intake, hormonal changes and rearrangement of the gastrointestinal anatomy. Positive outcomes resulting from the procedure include decreased mortality rates, normalization of HbA1c levels, decreased dependence on diabetic medications, and increased insulin sensitivity. Gastric bypass, specifically RYGB, appears to be a promising treatment for T2DM. Due to possible complications and limited research in some populations, treatment should be restricted to patients with a BMI \u3e 35 with concurrent diabetes. Patients with diabetes who qualify should be counseled on the potential benefits of gastric bypass as a viable option for diabetes management

Do Orientation-Based Differences in Nestbox Temperature Cause Differential Ectoparasite Load and Explain Patterns of Nest-Site Selection and Offspring Condition in Great Tits?

Nest ectoparasites have been linked previously to patterns of nest-site choice and breeding success in birds. Recent research has shown nestboxes facing south-southwest are occupied less frequently by great tits (Parus major) than identical boxes facing other directions, and are associated with reduced offspring condition. Here, we investigate the hypothesis that these findings are due to ectoparasite load being directionally nonuniform, possibly because of nonuniformity in nestbox internal temperature. Nests contained, in order of prevalence, hen fleas (Ceratophyllus gallinae), haematophagous blowflies (Protocalliphora spp.), biting lice (Ischnocera), and ticks/mites (Acari). Although southwest-facing nestboxes were significantly warmer than other boxes, there was no directional difference in total ectoparasite load or abundance of particular species. Similarly, there was no relationship between abundance of any ectoparasite species (either per-nest or per-chick) and avian offspring condition determined using wing length or relative mass. We discuss several possible, nonmutually exclusive, explanations for this, including compensatory responses, costs of parasitism being transferred to parents, and condition-dependent effects

Within- and Among-Observer Variation in Measurements of Animal Biometrics and their Influence on Accurate Quantification of Common Biometric-Based Condition Indices

Research using biometric data relies on consistent measurements within, and often among, observers. However, research into the relative importance of intra- and inter-observer variability is limited. More importantly, the influence of biometric variability on accurate quantification of biometric-based condition indices has not been analysed: it is unclear whether multiple errors become magnified or cancel one another out. Here, we quantify intra- and inter-specific variability in multiple biometrics, and derived condition indices, using museum bird specimens. Inter-observer variability was higher than intra-observer variability for all parameters. Measurement error (ME) varied from < 1% to > 50% for different biometrics. ME was magnified in condition estimates, reaching > 80% within-observers and > 90% among-observers. Significant differences in mean measurements were found for 17% and 67% of biometrics within-and among-observers, respectively; for condition indices, the figures were 50% and 67%, respectively. We discuss the implications of these findings for research into species' ecology, taxonomy and behaviour

Multiple doublesex-Related Genes Specify Critical Cell Fates in a C. elegans Male Neural Circuit

In most animal species, males and females exhibit differences in behavior and morphology that relate to their respective roles in reproduction. DM (Doublesex/MAB-3) domain transcription factors are phylogenetically conserved regulators of sexual development. They are thought to establish sexual traits by sex-specifically modifying the activity of general developmental programs. However, there are few examples where the details of these interactions are known, particularly in the nervous system.In this study, we show that two C. elegans DM domain genes, dmd-3 and mab-23, regulate sensory and muscle cell development in a male neural circuit required for mating. Using genetic approaches, we show that in the circuit sensory neurons, dmd-3 and mab-23 establish the correct pattern of dopaminergic (DA) and cholinergic (ACh) fate. We find that the ETS-domain transcription factor gene ast-1, a non-sex-specific, phylogenetically conserved activator of dopamine biosynthesis gene transcription, is broadly expressed in the circuit sensory neuron population. However, dmd-3 and mab-23 repress its activity in most cells, promoting ACh fate instead. A subset of neurons, preferentially exposed to a TGF-beta ligand, escape this repression because signal transduction pathway activity in these cells blocks dmd-3/mab-23 function, allowing DA fate to be established. Through optogenetic and pharmacological approaches, we show that the sensory and muscle cell characteristics controlled by dmd-3 and mab-23 are crucial for circuit function.In the C. elegans male, DM domain genes dmd-3 and mab-23 regulate expression of cell sub-type characteristics that are critical for mating success. In particular, these factors limit the number of DA neurons in the male nervous system by sex-specifically regulating a phylogenetically conserved dopamine biosynthesis gene transcription factor. Homologous interactions between vertebrate counterparts could regulate sex differences in neuron sub-type populations in the brain

Axon-Myelin Unit Blistering as Early Event in MS Normal Appearing White Matter

Objective: Multiple sclerosis (MS) is a chronic neuroinflammatory and neurodegenerative disease of unknown etiology. Although the prevalent view regards a CD4 +-lymphocyte autoimmune reaction against myelin at the root of the disease, recent studies propose autoimmunity as a secondary reaction to idiopathic brain damage. To gain knowledge about this possibility we investigated the presence of axonal and myelinic morphological alterations, which could implicate imbalance of axon-myelin units as primary event in MS pathogenesis. Methods: Using high resolution imaging histological brain specimens from patients with MS and non-neurological/non-MS controls, we explored molecular changes underpinning imbalanced interaction between axon and myelin in normal appearing white matter (NAWM), a region characterized by normal myelination and absent inflammatory activity. Results: In MS brains, we detected blister-like swellings formed by myelin detachment from axons, which were substantially less frequently retrieved in non-neurological/non-MS controls. Swellings in MS NAWM presented altered glutamate receptor expression, myelin associated glycoprotein (MAG) distribution, and lipid biochemical composition of myelin sheaths. Changes in tethering protein expression, widening of nodes of Ranvier and altered distribution of sodium channels in nodal regions of otherwise normally myelinated axons were also present in MS NAWM. Finally, we demonstrate a significant increase, compared with controls, in citrullinated proteins in myelin of MS cases, pointing toward biochemical modifications that may amplify the immunogenicity of MS myelin. Interpretation: Collectively, the impaired interaction of myelin and axons potentially leads to myelin disintegration. Conceptually, the ensuing release of (post-translationally modified) myelin antigens may elicit a subsequent immune attack in MS. ANN NEUROL 2021;89:711–725

Detoxification of Multiple Heavy Metals by a Half-Molecule ABC Transporter, HMT-1, and Coelomocytes of Caenorhabditis elegans

Developing methods for protecting organisms in metal-polluted environments is contingent upon our understanding of cellular detoxification mechanisms. In this regard, half-molecule ATP-binding cassette (ABC) transporters of the HMT-1 subfamily are required for cadmium (Cd) detoxification. HMTs have conserved structural architecture that distinguishes them from other ABC transporters and allows the identification of homologs in genomes of different species including humans. We recently discovered that HMT-1 from the simple, unicellular organism, Schizosaccharomyces pombe, SpHMT1, acts independently of phytochelatin synthase (PCS) and detoxifies Cd, but not other heavy metals. Whether HMTs from multicellular organisms confer tolerance only to Cd or also to other heavy metals is not known.Using molecular genetics approaches and functional in vivo assays we showed that HMT-1 from a multicellular organism, Caenorhabditis elegans, functions distinctly from its S. pombe counterpart in that in addition to Cd it confers tolerance to arsenic (As) and copper (Cu) while acting independently of pcs-1. Further investigation of hmt-1 and pcs-1 revealed that these genes are expressed in different cell types, supporting the notion that hmt-1 and pcs-1 operate in distinct detoxification pathways. Interestingly, pcs-1 and hmt-1 are co-expressed in highly endocytic C. elegans cells with unknown function, the coelomocytes. By analyzing heavy metal and oxidative stress sensitivities of the coelomocyte-deficient C. elegans strain we discovered that coelomocytes are essential mainly for detoxification of heavy metals, but not of oxidative stress, a by-product of heavy metal toxicity.We established that HMT-1 from the multicellular organism confers tolerance to multiple heavy metals and is expressed in liver-like cells, the coelomocytes, as well as head neurons and intestinal cells, which are cell types that are affected by heavy metal poisoning in humans. We also showed that coelomocytes are involved in detoxification of heavy metals. Therefore, the HMT-1-dependent detoxification pathway and coelomocytes of C. elegans emerge as novel models for studies of heavy metal-promoted diseases

The Grizzly, September 4, 1987

Convocation Greets Academic Year • Eisenhower Speech Kicks off New Year • Land of the Rising Sun • Student Life Shapes Up • Letter: Just Call Me Papa Juan • Just When You Thought It was Safe • Garrick Joins Resident Director Program • Hiel Begins Boosting Bookstore • Hager Brings New Ideas to College • Quinlin Continues Education • Notes: Women\u27s Stress Workshop; U.C. Honors Hardman and Neslen • Ursinus Football: For the Sheer Fun of It • Cross Country Runs Towards Promising Season • Hockey Travel to West Chester for Annual Tournament • Tannenbaum Sweeps CoSIDA Awards Again • Soccer Off to Rocky Start • The Dead Will Survive • Oh No! Video Blowouthttps://digitalcommons.ursinus.edu/grizzlynews/1190/thumbnail.jp