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A novel avian infectious bronchitis virus (IBV) variant, designated as GX-NN160421, was isolated from vaccinated chicken in Guangxi, China, in 2016. Based on analysis of the S1 gene sequence, GX-NN160421 belonged to the New-type 1 (GVI-1) strain. More importantly, three consecutive nucleotides (AAC) deletions were found in the highly conserved structure gene N. The serotype of GX-NN160421 was different from those of the commonly used vaccine strains. The mortality of the GX-NN160421 strain was 3.33%, which contrasted with 50% mortality in the clinical case, but high levels of virus shedding lasted at least 21 days. In conclusion, the first novel IBV variant with three-nucleotide-deletion in the N gene was identified, and this unique variant is low virulent but with a long time of virus shedding, indicating the continuing evolution of IBV and emphasizing the importance of limiting exposure to novel IBV strains as well as extensive monitoring of new IBVs. [ABSTRACT FROM AUTHOR]

Purpose: Soil denitrification rates and the roles Mn(II) and Fe(II) played as alternative electron donors were investigated by performing anoxic incubation experiments, using agricultural soils from Guangxi Autonomous Region, South China. Materials and methods: The dynamic of Mn(II) and Fe(II), electron contributions of Mn(II) and Fe(II) to denitrification, potential denitrification capacity, and gaseous-N composition were investigated. Results and discussion: The results indicated that Mn(II) and Fe(II) act as electron donors during the denitrification of paddy soils with high Mn and Fe contents. Coupling of denitrification and Fe(II) oxidation and coupling of denitrification and Mn(II) oxidation was found in paddy soils from the villages of Xialei. The maximum electron contributions of Mn(II) and Fe(II) to denitrification were similar, both reaching 18%, although the total Mn content was lower than the total Fe content. On the contrary, the roles and contributions of Mn(II) and Fe(II) to denitrification in soils from upland fields were not proved, even though all the studied agricultural soils had high Mn and Fe contents. Conclusions: The results suggested that Mn(II) is an important but previously ignored electron donor for denitrification and that Mn(II) plays a vital role in denitrification in paddy soils. [ABSTRACT FROM AUTHOR]