Cryptic Diversity of Isaria-like Species in Guizhou, China

Many Isaria-like species have recently been moved into more appropriate genera. However, more robust molecular phylogenetic analyses are still required for Isaria-like fungi to ensure accurate taxonomic identification. We analyzed these Isaria-like strains using multi-gene phylogenetics. Cryptic diversity was discovered in several Isaria farinosa strains, and two new species, Samsoniella pseudogunnii and S. pupicola, are proposed. Our results reveal that more attention needs to be paid to cryptic intraspecific diversity across different isolates and genotypes of the Isaria-like species, some of which will need to be transferred to Samsoniella. Interestingly, S. hepiali, with a very broad host distribution, has been widely used as a medicinal and edible cordycipitoid fungus.

Coevolution of Coronavirus and Paramyxovirus with Their Bat Hosts in the Same Geographical Areas

Bat-borne viruses are relatively host specific. In this study, coevolution analyses were conducted on coronaviruses and paramyxoviruses and their bat hosts to investigate the potential mechanisms of such host specificity. The published nucleotide sequences of the RNA dependent RNA polymerase (RdRp) gene of 60 coronaviruses from 37 bat species and those of the RNA polymerase large (L) gene of 36 paramyxoviruses from 29 bat species were analyzed. Each of the coevolution signal detected was tested and verified by the ParaFit and PACo functions of the R program. Significant coevolution signals were detected in coronaviruses and paramyxoviruses and their bat hosts, and closely related bat hosts were found to carry viruses that are closely related. Results also suggest that similar geographical distribution and close phylogenetic relationship may have resulted in infection of different bat species by the same strain of virus. As the natural hosts of certain viruses were mostly found in their endemic and surrounding areas, we speculate that the ancestors of bat hosts of Middle East respiratory syndrome coronaviruses (MERS-CoVs) may belong to the family of Vespertilionidae and are evolutionarily close to Neoromicia capensis and Pipistrellus hesperidus bats that are present in Africa and west Asia. In addition, we speculate that bat coronaviruses that are closely related to the novel coronavirus 2019 (COVID-19) may be found in bats related to Rhinolophus affinis. Although the coevolution between viruses and bat host is not surprised, this is the first systematical summary elucidating the relationship between coronaviruses, paramyxoviruses, host and geographical areas. It provides a theoretical basis for the viruses trace.Significance Bat-borne coronaviruses and paramyxoviruses have caused a number of outbreaks worldwide, posing a great threat to the safety of human life and property. It is important to understand the bats-viruses evolutionary history and rules for the viruse tracing. In our long-term surveillance of bat viruses, we found that they are family, genus or species-specific. In this study, we are committed to show this phenomena through co-phylogenetic analysis. Host distribution were taken into account as an important analytical factor in this study. Our resualts suggest that similar hosts carry similar viruses, similar distribution area may facilitate inter-species transmission of bat viruses, and several endemic area were overlap with the natural host distribution. This study is of great significance for further study of bats-viruses evolutionary history and enhanced our awareness of virus prevention and control.# J. Liang and C. Zhu contributed equally to this study.

Black hole masses of tidal disruption event host galaxies II

ABSTRACT We present new medium resolution, optical long-slit spectra of a sample of six ultraviolet (UV)/optical and 17 X-ray-selected tidal disruption event candidate host galaxies. We measure emission line ratios from the optical spectra, finding that the large majority of hosts are quiescent galaxies, while those displaying emission lines are generally consistent with star formation dominated environments; only three sources show clear evidence of nuclear activity. We measure bulge velocity dispersions using absorption lines and infer host black hole (BH) masses using the M – σ relation. While the optical and X-ray host BH masses are statistically consistent with coming from the same parent distribution, the optical host distribution has a visible peak near $M_{\rm BH} \sim 10^6 \, \mathrm{M}_\odot$, whereas the X-ray host distribution appears flat in MBH. We find a subset of X-ray-selected candidates that are hosted in galaxies significantly less luminous (Mg ∼ −16) and less massive (stellar mass ∼ 108.5–9 M⊙) than those of optical events. Using statistical tests we find suggestive evidence that, in terms of BH mass, stellar mass, and absolute magnitude, the hard X-ray hosts differ from the UV/optical and soft X-ray samples. Similar to individual studies, we find that the size of the emission region for the soft X-ray sample is much smaller than the optical emission region, consistent with a compact accretion disc. We find that the typical Eddington ratio of the soft X-ray emission is ∼ 0.01, as opposed to the optical events which have LBB ∼ LEdd. The latter seems artificial if the radiation is produced by self-intersection shocks, and instead suggests a connection to the supermassive black hole.