Conotoxin KM-RIIIJ reveals interplay between K1-channels and persistent sodium currents in proprioceptive DRG neurons.

Voltage-gated potassium channels (VGKCs) comprise the largest and most complex families of ion channels. Approximately 70 genes encode VGKC alpha subunits, which assemble into functional tetrameric channel complexes. These subunits can also combine to form heteromeric channels, significantly expanding the potential diversity of VGKCs.

χ-Conotoxins are an Evolutionary Innovation of Mollusk-Hunting Cone Snails as a Counter-Adaptation to Prey Defense.

Mollusk-hunting (molluscivorous) cone snails belong to a monophyletic group in Conus, a genus of venomous marine snails. The molluscivorous lineage evolved from ancestral worm-hunting (vermivorous) snails ∼18 Ma. To enable the shift to a molluscivorous lifestyle, molluscivorous cone snails must solve biological problems encountered when hunting other gastropods, namely: (i) preventing prey escape and (ii) overcoming the formidable defense of the prey in the form of the molluscan shell, a problem unique to molluscivorous Conus.

Using Constellation Pharmacology to Characterize a Novel α-Conotoxin from .

The venom of cone snails has been proven to be a rich source of bioactive peptides that target a variety of ion channels and receptors. α-Conotoxins (αCtx) interact with nicotinic acetylcholine receptors (nAChRs) and are powerful tools for investigating the structure and function of the various nAChR subtypes. By studying how conotoxins interact with nAChRs, we can improve our understanding of these receptors, leading to new insights into neurological diseases associated with nAChRs.

Studies of κ- and κ-tripyridylamine complexes of ruthenium and π-stacking by pyridyls.

The reaction of tris(pyridin-2-yl)amine with [CyRuCl] (Cy = p-isopropyltoluene or cymene) in refluxing diglyme led to the formation of cis-[RuCl{κ-(2-py)N}]·CHCl (1a) after recrystallization from chloroform/pentane, or cis-dichloridobis[tris(pyridin-2-yl)amine-κN,N']ruthenium(II) dichloromethane disolvate, [RuCl(CHN)]·2CHCl or cis-[RuCl{κ-(2-py)N}]·2CHCl (1b). Treatment of 1a with one equivalent of silver(I) hexafluoridoantimonate in dichloromethane gave [RuCl{κ-(2-py)N}{κ-(2-py)N}][SbF]·CHCl (2a). Crystallization of 2a from chloroform provided chlorido[tris(pyridin-2-yl)amine-κN,N'][tris(pyridin-2-yl)amine-κN,N',N'']ruthenium(II) hexafluoridoantimonate chloroform monosolvate, [RuCl(CHN)][SbF]·CHCl or [RuCl{κ-(2-py)N}{κ-(2-py)N}][SbF]·CHCl (2b).

A toxin-based approach to neuropeptide and peptide hormone discovery.

Peptide hormones and neuropeptides form a diverse class of bioactive secreted molecules that control essential processes in animals. Despite breakthroughs in peptide discovery, many signaling peptides remain undiscovered. Recently, we demonstrated the use of somatostatin-mimicking toxins from cone snails to identify the invertebrate ortholog of somatostatin.

Pre-egg hatch efficacy of dormant applications against Lymantria dispar (Lepidoptera: Erebidae).

Lymantria dispar L. is an invasive, non-native defoliating Lepidopteran established in North America that feeds on forest and urban trees. While many products are available to manage L.

CYP1B1-derived epoxides modulate the TRPA1 channel in chronic pain.

Pain is often debilitating, and current treatments are neither universally efficacious nor without risks. Transient receptor potential (TRP) ion channels offer alternative targets for pain relief, but little is known about the regulation or identities of endogenous TRP ligands that affect inflammation and pain. Here, transcriptomic and targeted lipidomic analysis of damaged tissue from the mouse spinal nerve ligation (SNL)-induced chronic pain model revealed a time-dependent increase in mRNA and a concurrent accumulation of 8,9-epoxyeicosatrienoic acid (EET) and 19,20-EpDPA post injury.

Integrating Venom Peptide Libraries Into a Phylogenetic and Broader Biological Framework.

The venomous marine snails are conventionally divided into three groups, the cone snails (family Conidae), the auger snails (family Terebridae) and the turrids (formerly all assigned to a single family, Turridae). In this study, a library of venom peptides from species conventionally assigned to the genus was correlated to a phylogenetic analysis. Nucleotide sequences of multiple genes from transcriptomes were used to assess the phylogenetic relationships across a diverse set of species.

The Tunicate Metabolite 2-(3,5-Diiodo-4-methoxyphenyl)ethan-1-amine Targets Ion Channels of Vertebrate Sensory Neurons.

Marine tunicates produce defensive amino-acid-derived metabolites, including 2-(3,5-diiodo-4-methoxyphenyl)ethan-1-amine (DIMTA), but their mechanisms of action are rarely known. Using an assay-guided approach, we found that out of the many different sensory cells in the mouse dorsal root ganglion (DRG), DIMTA selectively affected low-threshold cold thermosensors. Whole-cell electrophysiology experiments using DRG cells, channels expressed in oocytes, and human cell lines revealed that DIMTA blocks several potassium channels, reducing the magnitude of the afterhyperpolarization and increasing the baseline intracellular calcium concentration [Ca] of low-threshold cold thermosensors.

Nicotinic Acetylcholine Receptor Partial Antagonist Polyamides from Tunicates and Their Predatory Sea Slugs.

In our efforts to discover new drugs to treat pain, we identified molleamines A-E (-) as major neuroactive components of the sea slug, , and their prey, , tunicates. The chemical structures of molleamines were elucidated by spectroscopy and confirmed by the total synthesis of molleamines A () and C (). Synthetic completely blocked acetylcholine-induced calcium flux in peptidergic nociceptors (PNs) in the somatosensory nervous system.

Neuroactive Type-A γ-Aminobutyric Acid Receptor Allosteric Modulator Steroids from the Hypobranchial Gland of Marine Mollusk, .

In a program to identify pain treatments with low addiction potential, we isolated five steroids, conosteroids A-E (-), from the hypobranchial gland of the mollusk . Compounds - were active in a mouse dorsal root ganglion (DRG) assay that suggested that they might be analgesic. A synthetic analogue was used for a detailed pharmacological study.

Discovery of a Potent Conorfamide from Using a Novel Zebrafish Larvae Assay.

Natural products such as conotoxins have tremendous potential as tools for biomedical research and for the treatment of different human diseases. Conotoxins are peptides present in the venoms of predatory cone snails that have a rich diversity of pharmacological functions. One of the major bottlenecks in natural products research is the rapid identification and evaluation of bioactive molecules.

Chronicling changes in the somatosensory neurons after peripheral nerve injury.

Current drug discovery efforts focus on identifying lead compounds acting on a molecular target associated with an established pathological state. Concerted molecular changes that occur in specific cell types during disease progression have generally not been identified. Here, we used constellation pharmacology to investigate rat dorsal root ganglion neurons using two models of peripheral nerve injury: chronic constriction injury (CCI) and spinal nerve ligation (SNL).

Molecular characterization of frog vocal neurons using constellation pharmacology.

Identification and characterization of neuronal cell classes in motor circuits are essential for understanding the neural basis of behavior. It is a challenging task, especially in a non-genetic-model organism, to identify cell-specific expression of functional macromolecules. Here, we performed constellation pharmacology, calcium imaging of dissociated neurons to pharmacologically identify functional receptors expressed by vocal neurons in adult male and female African clawed frogs, .

An integrative approach to the facile functional classification of dorsal root ganglion neuronal subclasses.

Somatosensory neurons have historically been classified by a variety of approaches, including structural, anatomical, and genetic markers; electrophysiological properties; pharmacological sensitivities; and more recently, transcriptional profile differentiation. These methodologies, used separately, have yielded inconsistent classification schemes. Here, we describe phenotypic differences in response to pharmacological agents as measured by changes in cytosolic calcium concentration for the rapid classification of neurons in vitro; further analysis with genetic markers, whole-cell recordings, and single-cell transcriptomics validated these findings in a functional context.

Multiple-Lure Surveillance Trapping for Ips Bark Beetles, Monochamus Longhorn Beetles, and Halyomorpha halys (Hemiptera: Pentatomidae).

Invasions by insects introduced via international trade continue to cause worldwide impacts. Surveillance programs using traps baited with host volatiles and pheromones can detect incursions of nonnative species. We report on two experiments executed to determine if attractants for several insect species can be combined without compromising trap catches and detection ability of target species.

TRPA1 expression levels and excitability brake by K channels influence cold sensitivity of TRPA1-expressing neurons.

The molecular sensor of innocuous (painless) cold sensation is well-established to be transient receptor potential cation channel, subfamily M, member 8 (TRPM8). However, the role of transient receptor potential cation channel, subfamily A, member 1 (TRPA1) in noxious (painful) cold sensation has been controversial. We find that TRPA1 channels contribute to the noxious cold sensitivity of mouse somatosensory neurons, independent of TRPM8 channels, and that TRPA1-expressing neurons are largely non-overlapping with TRPM8-expressing neurons in mouse dorsal-root ganglia (DRG).

Interactions Among Latitude, Nematode Parasitization, and Female Sirex nigricornis (Hymenoptera: Siricidae) Fitness.

Sirex nigricornis F. (Hymenoptera: Siricidae) is an innocuous pine-inhabiting woodwasp native to eastern North America, utilizing dead or dying pine trees as hosts. Although S.

Cranio-facial remodeling in domestic dogs is associated with changes in larynx position.

The hyo-laryngeal complex is a multi-segmented structure integrating the oral and pharyngeal cavities and thus a variety of critical functions related to airway control, feeding, and vocal communication. Currently, we lack a complete understanding of how the hyoid complex, and the functions it mediates, can also be affected by changes in surrounding cranio-facial dimensions. Here, we explore these relationships in a breed of domestic dog, the Portuguese Water Dog, which is characterized by strong cranio-facial variation.

Classifying neuronal subclasses of the cerebellum through constellation pharmacology.

A pressing need in neurobiology is the comprehensive identification and characterization of neuronal subclasses within the mammalian nervous system. To this end, we used constellation pharmacology as a method to interrogate the neuronal and glial subclasses of the mouse cerebellum individually and simultaneously. We then evaluated the data obtained from constellation-pharmacology experiments by cluster analysis to classify cells into neuronal and glial subclasses, based on their functional expression of glutamate, acetylcholine, and GABA receptors, among other ion channels.

Effects of forest type and management on native wood wasp abundance (Hymenoptera: Siricidae) in Mississippi, United States.

The United States has a rich fauna of native Siricidae (wood wasps), but they are rarely studied because they have limited economic impact. In 2004, a non-native wood-boring pest, Sirex noctilio F., was found established in North America.

Defining modulatory inputs into CNS neuronal subclasses by functional pharmacological profiling.

Previously we defined neuronal subclasses within the mouse peripheral nervous system using an experimental strategy called "constellation pharmacology." Here we demonstrate the broad applicability of constellation pharmacology by extending it to the CNS and specifically to the ventral respiratory column (VRC) of mouse brainstem, a region containing the neuronal network controlling respiratory rhythm. Analysis of dissociated cells from this locus revealed three major cell classes, each encompassing multiple subclasses.

"Alas poor Yorick": What retrospective analysis of canine skulls can tell us about the impact of environmental factors on health.

Necropsies and extensive histological evaluation for clinical and sub-clinical disease of approximately three hundred Portuguese Water dogs are available as part of an ongoing study to assess their state of health at end of life. Throughout life these dogs enjoyed a variety of lifestyles and environments. Here we carry out retrospective quantitative assessments of life-time dietary input and physical activity for each dog.