Adam R Smith

Adam R Smith
  • PhD
  • Research Assistant at University of Iceland

About

32
Publications
4,527
Reads
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381
Citations
Current institution
University of Iceland
Current position
  • Research Assistant
Additional affiliations
August 2016 - October 2016
Indiana University Bloomington
Position
  • Lecturer
September 2011 - present
Indiana University Bloomington
Position
  • PostDoc Position

Publications

Publications (32)
Article
Full-text available
Author summary The electrical properties of excitable cells, such as those in muscle and nervous tissue, were enabled in large part by the evolution of voltage-gated ion channel genes. The regulated conduction of ions through these channels results in the propagation of electrical signals, facilitating communication between cells. Here, we investig...
Data
The domain 3–4 intracellular loop and the domain 4 S4–S5 linker from Nav channels of A. albifrons, D. rerio, and Homo sapiens to illustrate the strong conservation of these motifs across channels and species. Some amino acid substitutions occur in all Apteronotid scn4ab channels (blue dot), some in all Apteronotini (red dots), and 1 only in A. albi...
Data
Sequence alignment of A. albifrons muscle-specific scn4ab2 (top) and EMN/muscle–expressing scn4ab1 (bottom). Sequences derived from molecular cloning and Sanger sequencing. Dashed vertical lines indicate exon–intron boundaries. Exon numbering is according to alignment with D. rerio scn4ab. EMN, electromotorneuron. (TIF)
Data
Gene tree for scn4ab of Gymnotiforms and other teleosts rooted with scn4aa. Note that scn4ab is in single copy in 2 basal Apteronotids (“A” bonapartii and A. devenanzi) but duplicated into scn4ab1 and scn4ab2 before the divergence of the 3 members of the Apteronotini. Key events in the evolution of myogenic and neurogenic electric organs are noted....
Data
Supplemental sequences for chronogram. (DOCX)
Data
Activation and steady-state inactivation statistics. (DOCX)
Data
Relative expression of scn4aa and scn4ab1 in muscle and spinal cord derived from qRT-PCR in samples from A. albifrons. qRT-PCR, quantitative reverse transcription PCR. Expression was normalized to the housekeeping gene RPL13a. (TIF)
Data
Effects of Apteronotinti Nav1.4ab2 substitutions on equilibrium gating of human cardiac Nav1.5. A. Inactivation particle substitutions (see Figs 3 and S6) did not affect channel activation. (B) Apteronitini-specific domain 4 S4–S5 substitutions were associated with a 7–10 mV depolarizing shift in channel activation either alone or in conjunction wi...
Data
Gene accessions for gene tree and expression analysis. (DOCX)
Data
The axons of the brainstem pacemaker neurons run down the spinal cord (grey line) and synapse on the EMNs (teal). Top: in most adult Gymnotiforms, the axons of the EMNs synapse on the muscle-derived cells of the electric organ (salmon). In Apteronotids, the muscle-derived electric organ degenerates (former position faded), and the axons of the EMNs...
Data
The relative expression of sodium channels in muscle and spinal cord. Plots show the relative expression of all transfrags of each paralog in each species. For most paralogs, each transfrag has similar expression. The unduplicated scn4ab ortholog in non-Apteronotids is highlighted in purple, while the duplicate scn4ab parlaogs in Apteronotids are h...
Data
Normalized current–voltage relationship for the transient and persistent current for the cell recorded in Fig 4B. Note that the persistent current activates at a more negative voltage than the peak current and that it comprises a relatively greater fraction of the peak current in the range from −60 to −40 mV. Figure data included in S2 Data. (TIF)
Data
Apteronotinti Nav1.4ab substitutions in domain 4 S4–S5 sped recovery from fast inactivation of hNav1.5, which is partially mitigated by substitutions in the inactivation particle. Sodium channel currents were activated via 20-millisecond pulses to −20 mV, which were separated by a recovery interval at −120 mV for a specified length of time. (A) Nor...
Data
Beta subunits of muscle and spinal cord. Beta subunits are known to modify the properties of Nav channels. Note that different subunits are expressed in the muscle and spinal cord of Apteronotids. Figure data included in S1 Data. Nav, voltage-gated sodium. (TIF)
Data
Accession for genes used for chronogram. (DOCX)
Data
Data from expression and phylogeny figures. (XLSX)
Data
Data from electrophysiology figures. (XLSX)
Article
Full-text available
Sexually dimorphic behaviors are often regulated by androgens and estrogens. Steroid receptors and metabolism are control points for evolutionary changes in sexual dimorphism. Electric communication signals of South American knifefishes are a model for understanding the evolution and physiology of sexually dimorphic behavior. These signals are regu...
Article
Full-text available
The electric communication signals of weakly electric ghost knifefishes (Gymnotiformes: Apteronotidae) provide a valuable model system for understanding the evolution and physiology of behavior. Apteronotids produce continuous wave-type electric organ discharges (EODs) that are used for electrolocation and communication. The frequency and waveform...
Article
Hearing loss induces plasticity in excitatory and inhibitory neurotransmitter systems in auditory brain regions. Excitatory-inhibitory balance is also influenced by a range of neuromodulatory regulatory systems, but less is known about the effects of auditory damage on these networks. In this work, we studied the effects of acoustic trauma on neuro...
Chapter
Full-text available
Bladder grasshoppers are a small family of Orthoptera, with ear morphology and physiology, behavior, and sensory ecological features outstanding among acoustic insects. Acoustic communication is characterized by male and female duetting and male phonotaxis. The detection distance of the male signal is exceptional at about 2 km, achieved via stridul...
Article
Full-text available
Although the cichlids of Lake Malawi are an important model system for the study of sensory evolution and sexual selection, the evolutionary processes linking these two phenomena remain unclear. Prior works have proposed that evolutionary divergence is driven by sensory drive, particularly as it applies to the visual system. While evidence suggests...
Article
Associating quantitative genetic traits with quantitative behaviors is a relatively unexplored region of sensory neurobiology. The visual system is an ideal place to test models associating these levels of sensory perception. In this study, we reared cichlid fish from Lake Malawi in different ambient light environments. We then tested the visual se...
Article
Full-text available
The active transmission of information from sender to receiver is a fundamental component of communication, and is therefore a primary facet in evolutionary models of sexual selection. Research in several systems has underlined the importance of multiple sensory modalities in courtship signals. However, we still tend to think of individuals as havi...
Article
SUMMARY Lake Malawi (LM) cichlids have undergone heterochronic shifts in the expression of their cone opsin genes, the genes responsible for color vision. These shifts have generated species with short-, middle-, and long-wavelength-sensitive cone photoreceptors and visual systems. However, it is unclear when during the evolution of African cichlid...
Article
The expression of cone opsin genes is a primary determinant of the characteristics of colour vision. Interspecific variation in opsin expression is common in African cichlids. It is correlated with foraging among cichlids from Lake Malawi, and with ambient light environment among cichlids from Lake Victoria. In this study, we tested whether gene ex...
Article
Full-text available
The role of sequence variation in the spectral tuning of color vision is well established in many systems. This includes the cichlids of Lake Victoria where sequence variation has been linked to environmental light gradients and speciation. The cichlids of Lake Malawi are a similar model for visual evolution, but the role of gene sequence variation...
Article
Sensory systems play crucial roles in survival and reproduction. Therefore, sensory plasticity has important evolutionary implications. In this study, we examined retinal plasticity in five species of cichlid fish from Lake Malawi. We compared the cone opsin expression profiles of wild-caught fish to lab-reared F(1) that had been raised in a UV min...
Article
Full-text available
The cichlid fishes of Lake Malawi represent a prime example of a rapid evolutionary radiation via sexual selection. We show that in this group, acoustic communication significantly coincides with visual courtship displays. Specifically, individuals tend to use both multimodal and unimodal displays in successive courtship bouts. Behavioral analyses...
Article
Full-text available
Life-history theory suggests that the existence and persistence of phenotypic variation within species must be maintained through some advantage accruing to an individual following one developmental pathway over another. Here, we consider the adult lifespan of two highly differentiated male morphs and the female in the bladder grasshopper species B...
Article
The cichlids of Lake Malawi are often considered the quintessential example of a species radiation driven primarily by sexual selection and relying on visual cues. However, the description of sound production by courting males in several species raises the possibility that acoustic signaling may play a significant role in the selection process. Thi...

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