Phylogenetic and morphological analyses of Coniochaeta isolates recovered from Inner Mongolia and Yunnan revealed three new endolichenic fungal species.

Lichens are the result of a symbiotic interaction between fungi (mycobionts) and algae (phycobionts). Aside from mycobionts, lichen thalli can also contain non-lichenised fungal species, such as lichenicolous and endolichenic fungi. For this study, three surveys were conducted in China's Yunnan Province and Inner Mongolia Autonomous Region between 2017 and 2020. Several samples of four lichen species were collected during these surveys: Candelariafibrosa, Flavoparmeliacaperata, Flavopuncteliaflaventior and Ramalinasinensis. Six isolates of Coniochaeta were recovered from these four lichen species. The phylogenetic and morphological analyses revealed that two of these isolates were previously identified species, Coniochaetavelutinosa and C.acaciae. Those remaining were from potentially unknown species. We used molecular and morphological data to describe these previously-unknown species as Coniochaetafibrosae sp. nov., C.mongoliae sp. nov. and C.sinensis sp. nov. The findings of this study significantly improve our understanding of the variety and habitat preferences of Coniochaeta in China and globally.

Subtercola lobariae sp. nov., an actinobacterium of the family Microbacteriaceae isolated from the lichen Lobaria retigera.

An actinobacterium, designated strain 9583bT, was isolated from the lichen Lobaria retigera collected from Jiaozi Snow Mountain, Yunnan Province, China. Cells of strain 9583bT were Gram-stain-positive, aerobic, catalase-positive and oxidase-negative. The strain have a short rod-shaped, irregular morphology, and could grow at the temperature range of 4 to 28 °C. Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain 9583bT belonged to the genus Subtercola in the family Microbacteriaceae, and shared highest sequence similarity with the type strains of Subtercola frigoramans and Subtercola boreus (96.8 and 95.6 %, respectively). The peptidoglycan type was B2γ, with diaminobutyric acid as the diagnostic diamino acid. The polar lipids comprised of phosphatidylglycerol, diphosphatidylglycerol, five unidentified glycolipids and three unidentified phospholipids. The respiratory quinone was determined to be MK-10. While the major fatty acids (>5 %) of strain 9583bT were anteiso-C15 : 0, C14 : 0 2-OH and iso-C16 : 0, the 1,1-dimethoxy-alkanes included a-15 : 0 DMA, i-16 : 0 DMA, a-17 : 0 DMA and i-15 : 0 DMA. The genomic DNA G+C content of strain 9583bT was 66.8 mol%. On the basis of the phylogenetic, phenotypic and chemotaxonomic data in this study, strain 9583bT represents a novel species of the genus Subtercola, for which the name Subtercola lobariae sp. nov. is proposed. The type strain is 9583bT (=CGMCC 1.12976T=DSM 103962T).

Inefficient export of viral late mRNA contributes to fastidiousness of human adenovirus type 41 (HAdV-41) in 293 cells.

The human adenovirus (HAdV) early protein E1B55K interacts with E4orf6 to form an E3 ubiquitin ligase complex, which plays key roles in virus replication. To illustrate the reason for the fastidiousness of HAdV-41 in 293 cells, interaction between heterotypic E1B55K and E4orf6 proteins was investigated. HAdV-5 E1B55K could interact with HAdV-41 E4orf6, and vice versa. To form E1B55K/E4orf6 E3 ubiquitin ligase, HAdV-41 E4orf6 recruited Cul2 while HAdV-5 E4orf6 interacted with Cul5. The ligase complex formed by HAdV-5 E1B55K and HAdV-41 E4orf6 could cause the degradation of p53 and Mre11. However, in E1-deleted HAdV-41-infected 293TE7 cells, which expressed HAdV-41 E1B55K, viral late mRNAs were exported from nucleus more efficiently and accumulated to a higher concentration in cytoplasm when compared with that in infected 293 cells. These results suggested that interaction between homotypic E1B55K and E4orf6 was indispensable for efficient export of viral late mRNAs.

Vaccination influences the evolution of classical swine fever virus.

Classical swine fever is a serious, economically damaging disease caused by classical swine fever virus (CSFV). The CSFV is composed of two clades, according to phylogenetic estimates. Attenuated live vaccine such as HCLV, has been widely used to protect pigs from CSFV, but the influence of vaccination on the evolution of CSFV has not been studied. We conducted a systemic analysis of the impact of vaccination on the evolution of CSFV by comparing vaccine-related and non-vaccine-related CSFV groups. We found that vaccination may affect strain diversity and immune escape through recombination and point mutation. We also found that vaccination may influence the population dynamics, evolutionary rate and adaptive evolution of classical swine fever virus. Our evidence suggests that the vaccination might also change host adaptation through influencing codon usage of the virus in swine. These findings suggest that it is necessary to avoid excessive use of CSFV attenuated vaccines.

Identification of three H1N1 influenza virus groups with natural recombinant genes circulating from 1918 to 2009.

In this study, we identify a recombinant pb1 gene, a recombinant MP segment and a recombinant PA segment. The pb1 gene is recombined from two Eurasia swine H1N1 influenza virus lineages. It belongs to a H1N1 swine clade circulating in Europe and Asia from 1999 to 2009. The mosaic MP segment descends from H7 avian and H1N1 human virus lineages and pertains to a large human H1N1 virus family circulating in Asia, Europe and America from 1918 to 2007. The recombinant PA segment originated from two swine H1N1 lineages is found in a swine H1N1 group prevailing in Asia and Europe from 1999 to 2003. These results collectively falsify the hypothesis that influenza virus do not evolve by homologous recombination. Since recombination not only leads to virus genome diversity but also can alter its host adaptation and pathogenecity; the genetic mechanism should not be neglected in influenza virus surveillance.

Identification of a natural human serotype 3 parainfluenza virus.

Parainfluenza virus is an important pathogen threatening the health of animals and human, which brings human many kinds of disease, especially lower respiratory tract infection involving infants and young children. In order to control the virus, it is necessary to fully understand the molecular basis resulting in the genetic diversity of the virus. Homologous recombination is one of mechanisms for the rapid change of genetic diversity. However, as a negative-strand virus, it is unknown whether the recombination can naturally take place in human PIV. In this study, we isolated and identified a mosaic serotype 3 human PIV (HPIV3) from in China, and also provided several putative PIV mosaics from previous reports to reveal that the recombination can naturally occur in the virus. In addition, two swine PIV3 isolates transferred from cattle to pigs were found to have mosaic genomes. These results suggest that homologous recombination can promote the genetic diversity and potentially bring some novel biologic characteristics of HPIV.