Detection and characterization of novel luchacoviruses, genus Alphacoronavirus, in saliva and feces of meso-carnivores in the northeastern United States

IMPORTANCE

Several coronaviruses (CoVs) have been detected in domesticated, farmed, and wild meso-carnivores, causing a wide range of diseases and infecting diverse species, highlighting their important but understudied role in the epidemiology of these viruses. Assessing the viral diversity hosted in wildlife species is essential to understand their significance in the cross-species transmission of CoVs. Our focus here was on CoV discovery in meso-carnivores in the Northeast United States as a potential "hotspot" area with high density of humans and urban wildlife. This study identifies novel alphacoronaviruses circulating in multiple free-ranging wild and domestic species in this area and explores their potential epidemiological importance based on regions of the Spike gene, which are relevant for virus-host interactions.

Detection and characterization of novel luchacoviruses, genus Alphacoronavirus, shed in saliva and feces of meso-carnivores in the northeastern United States

Small to mid-sized carnivores, or meso-carnivores, comprise a group of diverse mammals, many of which can adapt to anthropogenically disturbed environments. Wild meso-carnivores living in urban areas may get exposed to or spread pathogens to other species, including stray/feral domestic animals. Several coronaviruses (CoVs) have been detected in domesticated and farmed meso-carnivores, but knowledge of CoVs circulating in free-ranging wild meso-carnivores remains limited. In this study, we analyzed 321 samples collected between 2016 and 2022 from 9 species of free-ranging wild meso-carnivores and stray/feral domestic cats in the northeastern United States. Using a pan-CoV PCR, we screened tissues, feces, and saliva, nasal, and rectal swabs. We detected CoV RNA in fecal and saliva samples of animals in four species: fisher (Pekania pennanti), bobcat (Lynx rufus), red fox (Vulpes vulpes), and domestic cat (Felis catus). Next-generation sequencing revealed that all these viruses belonged to the Luchacovirus subgenus (Alphacoronavirus genus), previously reported only in rodents and lagomorphs (i.e., rabbits). Genetic comparison of the 3'-end of the genome (~12,000bp) revealed that although the viruses detected group with, and have a genetic organization similar to other luchacoviruses, they are genetically distinct from those from rodents and lagomorphs. Genetic characterization of the spike protein revealed that the meso-carnivore luchacoviruses do not have an S1/S2 cleavage motif but do have highly variable structural loops containing cleavage motifs similar to those identified in certain pathogenic CoVs. This study highlights the importance of characterizing the spike protein of CoVs in wild species for further targeted epidemiologic monitoring.

Monochlorogallane: physical properties and structure of the gaseous molecule H2Ga(mu-Cl)2GaH2 as determined by vibrational, electron diffraction, and ab initio studies

Monochlorogallane, synthesized by the metathesis of gallium(III) chloride with an excess of trimethylsilane at ca. 250 K, has been characterized by chemical analysis, by its IR, Raman, and 1H NMR spectra, and by the products of its reaction with trimethylamine. The vibrational spectra of the vapor species isolated in solid Ar, N2, or CH4 matrixes at ca. 12 K imply the presence of only one species, viz. the dimer with an equilibrium structure conforming to D2h symmetry. The structure of this molecule has been determined by gas-phase electron diffraction (GED) measurements augmented by the results of ab initio molecular orbital calculations. An equilibrium structure with D2h symmetry has been assumed in the analysis of the electron diffraction pattern. However, as the molecule has a very low frequency Ga(mu-Cl)2Ga ring-puckering mode, a dynamic model was used to describe it with the aid of a set of pseudoconformers spaced at even intervals (deltadelta = 5 degrees, deltamax, = 20 delta) around the ring-puckering angle delta and Boltzmann-weighted according to a quartic potential V(delta) = V4delta4 + V2delta2. The differences in bond distances and angles between the different pseudoconformers were constrained to the values derived from the ab initio calculations employing second-order Moller-Plesset (MP2) methods (with all the electrons included in the correlation calculations) and a 6-311G(d) basis set. The results for the weighted average of the principal distances (ralpha) and angles (<alpha) (with estimated 1sigma uncertainties) from the combined GED/ab initio study are r(Ga-Cl) 2.350(2) A, r(Ga-H) 1.523(20) A, <Cl-Ga-Cl 89.7(5)degrees, <H-Ga-H 135.1 degrees, V4 3.0 x 10(-6) kcal mol(-1) deg(-4), and V2 6.0 x 10(-4) kcal mol(-1) deg(-2).