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In this study, we determined and genetically characterized three fowl adenoviruses isolated from chickens with inclusion body hepatitis (IBH) and hydropericardium syndrome (HPS) in China and assessed their pathogenicity. The full genome of HBQ12, BJH13 and JSJ13 was found to be 44,081, 43,966 and 43,756 nucleotides long, respectively. Sequence alignment and phylogenetic analysis revealed that strain HBQ12 and BJH13 were clustered together belonging to fowl adenoviruses D species and serotyped as FAdV-11, whereas strain JSJ13 was classified into fowl adenoviruses C species and serotyped as FAdV-4. To our knowledge, this is the first report of FAdV-4 strain circulating in China. The pathogenicity test showed that mortality for chickens infected with HBQ12 and JSJ13 within 21 days post infection (dpi) was 8.6% and 28.6%, respectively. Necropsy displayed mild or severe hepatitis and hydropericardium at 3 and 5 dpi as well as dead chickens. Viral DNA was detected in almost all tissues sampled from dead chickens. These results revealed that fowl adenovirus strains HBQ12 and JSJ13 are capable of causing IBH and HPS in chickens, indicating that preventive measures against FAdV infection on poultry farms should be implemented in China.

Coronavirus Disease 2019 (COVID-19) is caused by Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), a newly emerged coronavirus, and has been pandemic since March 2020 and led to many fatalities. Vaccines represent the most efficient means to control and stop the pandemic of COVID-19. However, currently there is no effective COVID-19 vaccine approved to use worldwide except for two human adenovirus vector vaccines, three inactivated vaccines, and one peptide vaccine for early or limited use in China and Russia. Safe and effective vaccines against COVID-19 are in urgent need. Researchers around the world are developing 213 COVID-19 candidate vaccines, among which 44 are in human trials. In this review, we summarize and analyze vaccine progress against SARS-CoV, Middle-East respiratory syndrome Coronavirus (MERS-CoV), and SARS-CoV-2, including inactivated vaccines, live attenuated vaccines, subunit vaccines, virus like particles, nucleic acid vaccines, and viral vector vaccines. As SARS-CoV-2, SARS-CoV, and MERS-CoV share the common genus, Betacoronavirus, this review of the major research progress will provide a reference and new insights into the COVID-19 vaccine design and development.

Emerging and seminal studies have shown that cell metabolism influences gene expression by modifying the epigenome, which can regulate stem cell pluripotency, differentiation, and somatic cell reprogramming. Core pluripotency factors and developmental regulators reciprocally control the expression of key metabolism genes and their encoded pathways. Recent technological advances enabling sensitive detection methods during early mammalian development revealed the state-specific and context-dependent coordination of signal transduction, histone modifications, and gene expression in developing, resting, and malnourished embryos. Here, we discuss metabolism as a potential driver of earliest cell fate through its influence on the epigenome and gene expression in embryos and their in vitro surrogate pluripotent stem cells.

Wild barley germplasms are a treasure trove of useful genes and provide rich sources of genetic variation for crop improvement. We carried out a hydroponic and pot evaluation of diverse germplasms in response to drought stress using 47 Tibet annual wild barley genotypes. Our results from the hydroponic experiment showed that SPAD (soilplant analyses development analyses, based on chlorophyll meter readings), plant height, and biomass of shoot/root were significantly reduced in plants exposed to drought stress (exposure of plant roots to air for 6 h daily for a period of 7 days) compared with control plants. There were significant differences among the 47 wild barley genotypes in terms of the reduction in these growth parameters, with variation coefficients and diversity indexes ranging from 23.2 to 49.1% and 1.46 to 1.62, respectively, suggesting a rich genetic diversity among the tested accessions. Genotypes XZ5 and XZ150 showed the least reduction, indicating their high tolerance to drought stress, while genotypes XZ54 and XZ147 showed the greatest reduction, and drought stress symptoms appeared rapidly and severely in these latter genotypes. The trends in the different responses of these genotypes to drought stress were fairly consistent in both the hydroponic and the two pot selection experiments, with XZ5 and XZ150 screened as drought-resistant genotypes and XZ54, XZ147 as drought-sensitive ones. Significant genotypic differences in leaf soluble sugar content and water use efficiency in response to drought stress were also observed in pot experiment two, with the droughttolerant genotype XZ5 showing a markedly higher recovery and the two drought-sensitive genotypes XZ54 and XZ147 showing a markedly lower recovery than the control plants.

No abstract

Infectious bronchitis (IB) is a highly contagious respiratory and urogenital disease of chickens caused by infectious bronchitis virus (IBV). This disease is of considerable economic importance and is primarily controlled through biosecurity and immunization with live attenuated and inactivated IB vaccines of various serotypes. In the present study, we tested the safety and efficacy of an attenuated predominant Chinese QX-like IBV strain. The results revealed that the attenuated strain has a clear decrease in pathogenicity for specific-pathogen-free (SPF) chickens compared with the parent strain. Strain YN-inoculated birds had clinical signs of varying severity with 30% mortality, while the attenuated group appeared healthy, with less tissue damage. The attenuated strain also had relatively low tissue replication rates and higher antibody levels. The superior protective efficacy of the attenuated strain was observed when vaccinated birds were challenged with a homologous or heterologous field IBV strain, indicating the potential of the attenuated YN (aYN) as a vaccine. Producing a vaccine targeting the abundant serotype in China is essential to reducing the economic impact of IB on the poultry industry.

Avian infectious bronchitis is a highly contagious disease caused by infectious bronchitis virus (IBV) that affects poultry production worldwide. The absence of vaccine cross-protection and the frequent emergence of new variant strains complicate control of IBV. Here we designed a study to measure the evolution dynamics of IBV strains in China. One hundered and seven complete sequences and 1022 S1-region sequences of Chinese IBVs isolated between 1994 and 2014 were analysed by using MEGA 5.0 software and the Bayesian analysis sampling trees (BEAST) method, and selection pressure on different proteins was assessed. The phylogenetic dissimilarity of different gene trees in the data set indicated possible recombination. Fourteen isolates were identified as recombinants, possibly generated from vaccines of the Massachusetts serotype in recombination with circulating viruses. The earliest IBV in China was found to have existed in the early 1900s, and continues to evolve at a rate of approximately 10 À5 substitutions per site per year. We found that purifying selection was the main evolutionary pressure in the protein-coding regions, while the S1 gene bears the greatest positive selection pressure. The proportion of QX-like genotype strains increased over time.These results indicate that the genotypes of Chinese IBVs have undergone a remarkable transition during the past 20 years.