Characterization of two pigeon paramyxovirus type 1 isolates in China.

For over three decades, there has been a continuing panzootic caused by a virulent variant avian paramyxovirus type 1 strain, the so-called pigeon paramyxovirus type 1. It is found primarily in racing pigeons, but it has also spread to wild birds and poultry. In this study, two pigeon paramyxovirus type 1 strains, SD12 and BJ13, obtained from diseased pigeons in China, were characterized. Phylogenetic analysis based on complete sequences allowed characterization of both strains as genotype VI, class II. Further phylogenetic analysis of a 374-nucleotide section of the fusion gene showed that SD12 fell into lineage VIbii-d and BJ13 into VIbii-f. The deduced amino acid sequence of the cleavage site of the fusion protein confirmed that both isolates contained the virulent motif (112)K/RRQKR↓F(117) at the cleavage site. Nevertheless, the values of intracerebral pathogenicity indices showed the SD12 isolate to be a velogenic strain and BJ13 isolate to be a mesogenic strain. The SD12 isolate was further investigated via clinical observation, RNA detection, histopathology and viral serology in experimentally infected 3-week-old chickens. It showed a mild pathological phenotype in chickens, with viral replication restricted to a few tissues. The molecular mechanism for the SD12 isolate to have a virulent motif but low levels of virulence for chickens requires further study.

[Performance and Membrane Fouling Properties in an Anaerobic Membrane Bioreactor for Salty Wastewater].

In the research, an anaerobic membrane bioreactor (AnMBR) was used to treat simulated salty organic wastewater, and the effect of salinity on reactor performance and membrane fouling properties was investigated. The results indicated that when the influent salinity increased gradually but was lower than 9.1 g·L-1, the reactor ran stably and the effluent performance was good. When the salinity increased to 10 g·L-1, the COD removal-efficiency, gas production, and methane content decreased significantly; meanwhile, the sludge concentration, sludge volume index (SVI), soluble microbial products (SMP), and extracellular polymeric substance (EPS) levels became elevated at first and then declined with the rising salinity. The system developed compact flocs and a high settling ability. The hollow fiber membrane module was run for three cycles in 118 d. The membrane operating cycle was extended from 31 d to 48 d with the increasing salinity, which favored the control of membrane fouling. SEM-EDX analysis results revealed that there were similar crystalline substances in the film membrane foulants, and Na, Mg, Al, Si, Cl, K, Ca, and Fe were the main inorganic elements. Excitation emission matrix (EEM) analysis results demonstrated that proteins and humic acids were the main components of the organic membrane foulants.

Molecular characterization of chicken-derived genotype VIId Newcastle disease virus isolates in China during 2005-2012 reveals a new length in hemagglutinin-neuraminidase.

Newcastle disease (ND) is one of the most important diseases of poultry, and causes severe economic losses in the global poultry industry. Although all Newcastle disease virus (NDV) isolates belong to a single serotype, significant genetic diversity has been described between different NDV isolates. Here, we report the molecular characterization of 23 virulent genotype VIId NDV isolates of class II circulating in China. Phylogenetic construction and analysis revealed the existence of distinctly genomic and amino acid differences that clearly distinguished these isolates from other typical NDV genotypes and vaccine strains. We also report a new 582-amino-acid hemagglutinin-neuraminidase in genotype VII NDV strains. This is believed to be the first study to investigate systematically the most predominant NDV strains, and provides more information on the genetic nature of genotype VIId NDV of class II circulating in China.