Temporal stability in the genetic structure of Sarcoptes scabiei under the host-taxon law: empirical evidences from wildlife-derived Sarcoptes mite in Asturias, Spain

<p>Abstract</p> <p>Background</p> <p>Implicitly, parasite molecular studies assume temporal genetic stability. In this study we tested, for the first time to our knowledge, the extent of changes in genetic diversity and structure of <it>Sarcoptes </it>mite populations from Pyrenean chamois (<it>Rupicapra pyrenaica</it>) in Asturias (Spain), using one multiplex of 9 microsatellite markers and <it>Sarcoptes </it>samples from sympatric Pyrenean chamois, red deer (<it>Cervus elaphus</it>), roe deer (<it>Capreolus capreolus</it>) and red fox (<it>Vulpes vulpes</it>).</p> <p>Results</p> <p>The analysis of an 11-years interval period found little change in the genetic diversity (allelic diversity, and observed and expected heterozygosity). The temporal stability in the genetic diversity was confirmed by population structure analysis, which was not significantly variable over time. Population structure analysis revealed temporal stability in the genetic diversity of <it>Sarcoptes </it>mite under the host-taxon law (herbivore derived- and carnivore derived-<it>Sarcoptes </it>mite) among the sympatric wild animals from Asturias.</p> <p>Conclusions</p> <p>The confirmation of parasite temporal genetic stability is of vital interest to allow generalizations to be made, which have further implications regarding the genetic structure, epidemiology and monitoring protocols of the ubiquitous <it>Sarcoptes </it>mite. This could eventually be applied to other parasite species.</p

The reductive glycine pathway allows autotrophic growth of Desulfovibrio desulfuricans

Supplementary informationis available for this paper athttps://doi.org/10.1038/s41467-020-18906-7Six CO2 fixation pathways are known to operate in photoautotrophic and chemoautotrophic microorganisms. Here, we describe chemolithoautotrophic growth of the sulphate-reducing bacterium Desulfovibrio desulfuricans (strain G11) with hydrogen and sulphate as energy substrates. Genomic, transcriptomic, proteomic and metabolomic analyses reveal that D. desulfuricans assimilates CO2 via the reductive glycine pathway, a seventh CO2 fixation pathway. In this pathway, CO2 is first reduced to formate, which is reduced and condensed with a second CO2 to generate glycine. Glycine is further reduced in D. desulfuricans by glycine reductase to acetyl-P, and then to acetyl-CoA, which is condensed with another CO2 to form pyruvate. Ammonia is involved in the operation of the pathway, which is reflected in the dependence of the autotrophic growth rate on the ammonia concentration. Our study demonstrates microbial autotrophic growth fully supported by this highly ATP-efficient CO2 fixation pathway.We acknowledge Änne-Michaelis and William Newell for assistance with the LC-MS forthe metabolomics experiments and Daniel Amador-Noguez for access to the LC-MS usedfor13C intracellular metabolomic analysis. We thank Ines Cardoso Pereira and John vander Oost for critically reading the manuscript. This research was funded by the Neth-erlands Organisation for Scientific Research (NWO) through SIAM Gravitation Grant024.002.002 and the Innovation Program Microbiology (WUR), NJC acknowledgesfunding from NWO through a Rubicon Grant (019.163LW.035) and a Veni Grant(VI.Veni.192.156).info:eu-repo/semantics/publishedVersio

Complex body size trends in the evolution of sloths (Xenarthra: Pilosa)

Background Extant sloths present an evolutionary conundrum in that the two living genera are superficially similar (small-bodied, folivorous, arboreal) but diverged from one another approximately 30 million years ago and are phylogenetically separated by a radiation of medium to massive, mainly ground-dwelling, taxa. Indeed, the species in the two living genera are among the smallest, and perhaps most unusual, of the 50+ known sloth species, and must have independently and convergently evolved small size and arboreality. In order to accurately reconstruct sloth evolution, it is critical to incorporate their extinct diversity in analyses. Here, we used a dataset of 57 species of living and fossil sloths to examine changes in body mass mean and variance through their evolution, employing a general time-variable model that allows for analysis of evolutionary trends in continuous characters within clades lacking fully-resolved phylogenies, such as sloths. Results Our analyses supported eight models, all of which partition sloths into multiple subgroups, suggesting distinct modes of body size evolution among the major sloth lineages. Model-averaged parameter values supported trended walks in most clades, with estimated rates of body mass change ranging as high as 126 kg/million years for the giant ground sloth clades Megatheriidae and Nothrotheriidae. Inclusion of living sloth species in the analyses weakened reconstructed rates for their respective groups, with estimated rates for Megalonychidae (large to giant ground sloths and the extant two-toed sloth) were four times higher when the extant genus Choloepus was excluded. Conclusions Analyses based on extant taxa alone have the potential to oversimplify or misidentify macroevolutionary patterns. This study demonstrates the impact that integration of data from the fossil record can have on reconstructions of character evolution and establishes that body size evolution in sloths was complex, but dominated by trended walks towards the enormous sizes exhibited in some recently extinct forms

Oldest known cranium of a juvenile New World monkey (Early Miocene, Patagonia, Argentina): implications for the taxonomy and the molar eruption pattern of early platyrrhines.

A juvenile cranium of Homunculus patagonicus Ameghino, 1891a from the late Early Miocene of Santa Cruz Province (Argentina) provides the first evidence of developing cranial anatomy for any fossil platyrrhine. The specimen preserves the rostral part of the cranium with deciduous and permanent alveoli and teeth. The dental eruption sequence in the new specimen and a reassessment of eruption patterns in living and fossil platyrrhines suggest that the ancestral platyrrhine pattern of tooth replacement was for the permanent incisors to erupt before M(1), not an accelerated molar eruption (before the incisors) as recently proposed. Two genera and species of Santacrucian monkeys are now generally recognized: H. patagonicus Ameghino, 1891a and Killikaike blakei Tejedor et al., 2006. Taxonomic allocation of Santacrucian monkeys to these species encounters two obstacles: 1) the (now lost) holotype and a recently proposed neotype of H. patagonicus are mandibles from different localities and different geologic members of the Santa Cruz Formation, separated by approximately 0.7 million years, whereas the holotype of K. blakei is a rostral part of a cranium without a mandible; 2) no Santacrucian monkey with associated cranium and mandible has ever been found. Bearing in mind these uncertainties, our examination of the new specimen as well as other cranial specimens of Santacrucian monkeys establishes the overall dental and cranial similarity between the holotype of Killikaike blakei, adult cranial material previously referred to H. patagonicus, and the new juvenile specimen. This leads us to conclude that Killikaike blakei is a junior subjective synonym of H. patagonicus

Fossil localities of the Santa Cruz Formation (Early Miocene, Patagonia, Argentina) prospected by Carlos Ameghino in 1887 revisited and the location of the Notohippidian

Between January and September of 1887 Carlos Ameghino carried out his first geologic and paleontological expedition to the Río Santa Cruz, Patagonia. Based on the fossils and geologic information compiled, in 1887 and 1889, Florentino Ameghino named more than 120 new species of extinct mammals and his Formación Santacruceña and Piso Santacruceño (Santacrucian stage). Data published by both brothers state that the specimens were collected in outcrops by the Río Santa Cruz, between 90 and 200km west of its mouth. However, information in the posthumously published letters and Travel Diary of C. Ameghino allows us to recognize a fourth locality, Río Bote, at about 50km further southwest. In 1900, 1902, F. Ameghino divided the Piso Santacruceño in a younger étage Santacruzienne and older étage Notohippidéen, restricting the geographical distribution of the latter to Kar Aiken locality, northeast of Lago Argentino. However, 15 of the 54 species that F. Ameghino listed as exclusively Notohippidian stage already had been named on specimens collected South to the Río Santa Cruz in 1887, two year prior to C. Ameghino's first visit to Kar Aiken. Based on historical information and several expeditions to the Río Santa Cruz and its environs, in this contribution we establish the geographical locations of the 1887 localities, formalize their names, evaluate the stratigraphic position of the fossil-bearing levels, and analyze the geographic extension of the Notohippidian, inferring that Río Bote is where C. Ameghino first collected species that came to define the Notohippidian. © 2014 Elsevier Ltd