Abstract
Ammonia-oxidizing archaea (AOA) are key players in the nitrogen cycle of polar soils. Here, we analyzed metagenomic data from tundra soils in Rásttigáisá, Norway, and recovered four metagenome-assembled genomes (MAGs) assigned to the genus ‘UBA10452’, an uncultured lineage of putative AOA in the order Nitrososphaerales (‘terrestrial group I.1b’), phylum Thaumarchaeota. Analysis of other eight previously reported MAGs and publicly available amplicon sequencing data revealed that the UBA10452 lineage is predominantly found in acidic polar and alpine soils. In particular, UBA10452 MAGs were more abundant in highly oligotrophic environments such as mineral permafrost than in more nutrient-rich, vegetated tundra soils. UBA10452 MAGs harbour multiple copies of genes related to cold tolerance, particularly genes involved in DNA replication and repair. Based on the phylogenetic, biogeographic, and ecological characteristics of 12 UBA10452 MAGs, which include a high-quality MAG (90.8% complete, 3.9% redundant) with a nearly complete 16S rRNA gene, we propose a novel Candidatus genus, Ca. Nitrosopolaris, with four species representing clear biogeographic/habitat clusters.
Trichomonas vaginalis (Tv) is a flagellated protist parasite that infects the human urogenital tract. The symbiotic relationship between Tv and Mycoplasma hominis has been reported. Recent studies have identified a new Mycoplasma strain, Candidatus Mycoplasma girerdii (Ca. M. girerdii), present in the vaginal secretions of women and have shown that this strain may be related to trichomoniasis. Here, we evaluated the presence of Tv, M. hominis and Ca. M. girerdii in 312 clinical samples from adult women diagnosed with vaginitis in Zhangye, Gansu province, China. Among these samples, 94, 153, and 48 were Tv, M. hominis and Ca. M. girerdii positive, respectively. Moreover, Tv was highly frequent in 17–30-year-old women in this region. Forty samples (83.3%) positive for Ca. M. girerdii were also positive for Tv. Six Tv isolates were successfully cultured, including five isolates that showed symbiotic relationships with Mycoplasma. This is the first report to evaluate the genetic characteristics of Ca. M. girerdii in China and may therefore provide insights into the effects of Ca. M. girerdii on the reproductive health of women.
Tijekom 2015. godine u Baranji je došlo do masovnog propadanja nasada marelice. Iako sve upućuje da je uzrok pojave smrzavanje, određen broj voćnjaka je pregledan kako bi se u njima utvrdila eventualna prisutnost biljnih bolesti. U osam nasada marelice u Baranji sakupljena su 63 uzorka sa stabala sa simptomima odumiranja te su analizirani na prisutnost patogena 'Candidatus Phytoplasma prunorum', uzročnika europske žutice koštičavog voća. Fitoplazma je utvrđena u četiri od osam nasada, ukupno u 15 od 63 uzoraka (24 %). Masovno propadanje marelice u Baranji tijekom 2015. nije povezano sa zarazom fitoplazme 'Ca. Phytoplasma prunorum', no prisutnost tog patogena potrebno je uzeti u obzir kod uzgoja osjetljivih voćnih vrsta i proizvodnje sadnog materijala na tom području.