Why the brown ghost chirps at night.

Since the pioneering work by Moeller, Szabo, and Bullock, weakly electric fish have served as a valuable model for investigating spatial and social cognitive abilities in a vertebrate taxon usually less accessible than mammals or other terrestrial vertebrates. These fish, through their electric organ, generate low-intensity electric fields to navigate and interact with conspecifics, even in complete darkness. The brown ghost knifefish is appealing as a study subject due to a rich electric 'vocabulary', made by individually variable and sex-specific electric signals.

Unraveling the complex phylogeographic history of freshwater fishes in Lower Central America: A study of the electric fish Brachyhypopomus occidentalis.

Lower Central America (LCA) has a complex biogeographic history shaped by the rise of the Isthmus of Panama and the global climatic oscillations of the Pleistocene. These events have been crucial in structuring biodiversity in LCA, but their consequences for the distribution and partitions of genetic diversity across the region remain to be elucidated. We combined complete mitochondrial genomes and nuclear ultraconserved elements (UCEs) to study the phylogeographic history and population genetic structure of the electric fish Brachyhypopomus occidentalis in LCA.

Osteoblast-Specific Overexpression of Nucleolar Protein /RIOX1 in Mouse Embryos Leads to Osteoporosis in Adult Mice.

In previous study, we showed that nucleolar protein 66 (NO66) is a chromatin modifier and negatively regulates Osterix activity as well as mesenchymal progenitor differentiation. Genetic ablation of the 66 () gene in cells of the 1-expressing mesenchymal lineage leads to acceleration of osteochondrogenic differentiation and a larger skeleton in adult mice, whereas mesenchyme-specific overexpression of 66 inhibits osteochondrogenesis resulting in dwarfism and osteopenia. However, the impact of NO66 overexpression in cells of the osteoblast lineage remains largely undefined.

Individual-specific levels of CTG•CAG somatic instability are shared across multiple tissues in myotonic dystrophy type 1.

Myotonic dystrophy type 1 is a complex disease caused by a genetically unstable CTG repeat expansion in the 3'-untranslated region of the DMPK gene. Age-dependent, tissue-specific somatic instability has confounded genotype-phenotype associations, but growing evidence suggests that it also contributes directly toward disease progression. Using a well-characterized clinical cohort of DM1 patients from Costa Rica, we quantified somatic instability in blood, buccal cells, skin and skeletal muscle.

Myotonic dystrophy type 1 (DM1) clinical subtypes and CTCF site methylation status flanking the CTG expansion are mutant allele length-dependent.

Myotonic dystrophy type 1 (DM1) is a complex disease with a wide spectrum of symptoms. The exact relationship between mutant CTG repeat expansion size and clinical outcome remains unclear. DM1 congenital patients (CDM) inherit the largest expanded alleles, which are associated with abnormal and increased DNA methylation flanking the CTG repeat.

The weakly electric fish, Apteronotus albifrons, actively avoids experimentally induced hypoxia.

Anthropogenic environmental degradation has led to an increase in the frequency and prevalence of aquatic hypoxia (low dissolved oxygen concentration, DO), which may affect habitat quality for water-breathing fishes. The weakly electric black ghost knifefish, Apteronotus albifrons, is typically found in well-oxygenated freshwater habitats in South America. Using a shuttle-box design, we exposed juvenile A.

Distribution of the cholinergic nuclei in the brain of the weakly electric fish, Apteronotus leptorhynchus: Implications for sensory processing.

Acetylcholine acts as a neurotransmitter/neuromodulator of many central nervous system processes such as learning and memory, attention, motor control, and sensory processing. The present study describes the spatial distribution of cholinergic neurons throughout the brain of the weakly electric fish, Apteronotus leptorhynchus, using in situ hybridization of choline acetyltransferase mRNA. Distinct groups of cholinergic cells were observed in the telencephalon, diencephalon, mesencephalon, and hindbrain.

Longitudinal increases in somatic mosaicism of the expanded CTG repeat in myotonic dystrophy type 1 are associated with variation in age-at-onset.

In myotonic dystrophy type 1 (DM1), somatic mosaicism of the (CTG)n repeat expansion is age-dependent, tissue-specific and expansion-biased. These features contribute toward variation in disease severity and confound genotype-to-phenotype analyses. To investigate how the (CTG)n repeat expansion changes over time, we collected three longitudinal blood DNA samples separated by 8-15 years and used small pool and single-molecule PCR in 43 DM1 patients.

Towards development of a statistical framework to evaluate myotonic dystrophy type 1 mRNA biomarkers in the context of a clinical trial.

Myotonic dystrophy type 1 (DM1) is a rare genetic disorder, characterised by muscular dystrophy, myotonia, and other symptoms. DM1 is caused by the expansion of a CTG repeat in the 3'-untranslated region of DMPK. Longer CTG expansions are associated with greater symptom severity and earlier age at onset.

Plasma proteomic profiles differ between European and North American myotid bats colonized by Pseudogymnoascus destructans.

Emerging fungal diseases have become challenges for wildlife health and conservation. North American hibernating bat species are threatened by the psychrophilic fungus Pseudogymnoascus destructans (Pd) causing the disease called white-nose syndrome (WNS) with unprecedented mortality rates. The fungus is widespread in North America and Europe, however, disease is not manifested in European bats.

Tracking activity patterns of a multispecies community of gymnotiform weakly electric fish in their neotropical habitat without tagging.

Field studies on freely behaving animals commonly require tagging and often are focused on single species. Weakly electric fish generate a species- and individual-specific electric organ discharge (EOD) and therefore provide a unique opportunity for individual tracking without tagging. Here, we present and test tracking algorithms based on recordings with submerged electrode arrays.

Effects of hypoxia on aerobic metabolism and active electrosensory acquisition in the African weakly electric fish Marcusenius victoriae.

Environmental hypoxia has effected numerous and well-documented anatomical, physiological and behavioural adaptations in fishes. Comparatively little is known about hypoxia's impacts on sensing because it is difficult to quantify sensory acquisition in vivo. Weakly electric fishes, however, rely heavily on an easily-measurable sensory modality-active electric sensing-whereby individuals emit and detect electric organ discharges (EODs).

Tempo and mode of allopatric divergence in the weakly electric fish Sternopygus dariensis in the Isthmus of Panama.

Spatial isolation is one of the main drivers of allopatric speciation, but the extent to which spatially-segregated populations accumulate genetic differences relevant to speciation is not always clear. We used data from ultraconserved elements (UCEs) and whole mitochondrial genomes (i.e.

The effect of normoxia exposure on hypoxia tolerance and sensory sampling in a swamp-dwelling mormyrid fish.

Effects of energetic limitations on the performance of sensory systems are generally difficult to quantify. Weakly electric fishes provide an ideal model system to quantify the effects of metabolic stressors on sensory information acquisition, because they use an active-sensing strategy that permits easy measurement of the sensing effort. These fishes discharge an electric signal and sense perturbations of the resulting electric field.

Consensus-based care recommendations for adults with myotonic dystrophy type 2.

Purpose Of Review: Myotonic dystrophy type 2 (DM2) is a rare, progressive multisystem disease particularly affecting the skeletal muscle. A causal therapy is not yet available; however, prompt, appropriate symptomatic treatments are essential to limit disease-related complications. Evidence-based guidelines to assist medical practitioners in the care of DM2 patients do not exist.

Analysis of mutational dynamics at the DMPK (CTG)n locus identifies saliva as a suitable DNA sample source for genetic analysis in myotonic dystrophy type 1.

Genotype-to-phenotype correlation studies in myotonic dystrophy type 1 (DM1) have been confounded by the age-dependent, tissue-specific and expansion-biased features of somatic mosaicism of the expanded CTG repeat. Previously, we showed that by controlling for the confounding effects of somatic instability to estimate the progenitor allele CTG length in blood DNA, age at onset correlations could be significantly improved. To determine the suitability of saliva DNA as a source for genotyping, we used small pool-PCR to perform a detailed quantitative study of the somatic mutational dynamics of the CTG repeat in saliva and blood DNA from 40 DM1 patients.

Mitogenomics of Central American weakly-electric fishes.

Electric fishes are a diverse group of freshwater organisms with the ability to generate electric organ discharges (EODs) that are used for communication and electrolocation. This group (ca. 200 species) has originated in South America, and six species colonized the Central American Isthmus.

Effects of hypoxia on swimming and sensing in a weakly electric fish.

Low dissolved oxygen (hypoxia) can severely limit fish performance, especially aerobically expensive behaviours including swimming and acquisition of sensory information. Fishes can reduce oxygen requirements by altering these behaviours under hypoxia, but the underlying mechanisms can be difficult to quantify. We used a weakly electric fish as a model system to explore potential effects of hypoxia on swim performance and sensory information acquisition, which enabled us to non-invasively record electric signalling activity used for active acquisition of sensory information during swimming.

Statistics of Natural Communication Signals Observed in the Wild Identify Important Yet Neglected Stimulus Regimes in Weakly Electric Fish.

Sensory systems evolve in the ecological niches that each species is occupying. Accordingly, encoding of natural stimuli by sensory neurons is expected to be adapted to the statistics of these stimuli. For a direct quantification of sensory scenes, we tracked natural communication behavior of male and female weakly electric fish, , in their Neotropical rainforest habitat with high spatiotemporal resolution over several days.

Synergistic and additive effect of retinoic acid in circumventing resistance to p53 restoration.

mutations occur in ∼50% of all human tumors, with increased frequency in aggressive cancers that are notoriously difficult to treat. Additionally, p53 missense mutations are remarkably predictive of refractoriness to chemo/radiotherapy in various malignancies. These observations have led to the development of mutant p53-targeting agents that restore p53 function.

Pattern of aromatase mRNA expression in the brain of a weakly electric fish, Apteronotus leptorhynchus.

Aromatase is a steroidogenic enzyme involved in the conversion of testosterone into estradiol. Teleosts are unique among vertebrates in possessing two distinct aromatase genes that show different expression patterns within the body. Since the brain is the essential organ underlying the control of behavior, an understanding of the expression pattern of aromatase in the brain can help to identify neural circuits and behaviors that are most likely to be affected by aromatase activity.

Genome-wide imaging association study implicates functional activity and glial homeostasis of the caudate in smoking addiction.

Background: Nearly 6 million deaths and over a half trillion dollars in healthcare costs worldwide are attributed to tobacco smoking each year. Extensive research efforts have been pursued to elucidate the molecular underpinnings of smoking addiction and facilitate cessation. In this study, we genotyped and obtained both resting state and task-based functional magnetic resonance imaging from 64 non-smokers and 42 smokers.

Hypoxia acclimation increases novelty response strength during fast-starts in the African mormyrid, Marcusenius victoriae.

Many fishes perform quick and sudden swimming maneuvers known as fast-starts to escape when threatened. In pulse-type weakly electric fishes these responses are accompanied by transient increases in the rate of electric signal production known as novelty responses. While novelty responses may increase an individual's information about their surroundings, they are aerobically powered and may come at a high energetic cost when compared to fast-starts, which rely primarily on anaerobic muscle.

(CCUG) RNA toxicity in a model of myotonic dystrophy type 2 (DM2) activates apoptosis.

The myotonic dystrophies are prototypic toxic RNA gain-of-function diseases. Myotonic dystrophy type 1 (DM1) and type 2 (DM2) are caused by different unstable, noncoding microsatellite repeat expansions - (CTG) in and (CCTG) in Although transcription of mutant repeats into (CUG) or (CCUG) appears to be necessary and sufficient to cause disease, their pathomechanisms remain incompletely understood. To study the mechanisms of (CCUG) toxicity and develop a convenient model for drug screening, we generated a transgenic DM2 model in the fruit fly with (CCUG) repeats of variable length (=16 and 106).

Subsecond Sensory Modulation of Serotonin Levels in a Primary Sensory Area and Its Relation to Ongoing Communication Behavior in a Weakly Electric Fish.

Serotonergic neurons of the raphe nuclei of vertebrates project to most regions of the brain and are known to significantly affect sensory processing. The subsecond dynamics of sensory modulation of serotonin levels and its relation to behavior, however, remain unknown. We used fast-scan cyclic voltammetry to measure serotonin release in the electrosensory system of weakly electric fish, .