Seroprevalence of Toxoplasma gondii infection in breeding sows in Western Fujian Province, China.

The objective of the present investigation was to estimate the seroprevalence T. gondii infection in breeding sows in Western Fujian Province, the People's Republic of China. Sera collected from breeding sows during 2006-2007 from 6 different regions in Western Fujian Province were assayed for antibodies to T. gondii by an indirect hemagglutination antibody (IHA) test. Antibodies to T. gondii were detected in 87 (14.38%) of 605 breeding sows. Differences in seroprevalence were observed between sampling regions, ranging from 10.14% to 37.50%. The present investigation demonstrated that the prevalence of T. gondii infection in breeding sows in Fujian Province was high. Integrated control strategies and measures should be implemented to prevent and control T. gondii infection in breeding sows, which in turn will have significant implications for the control of human infection with T. gondii in this province.

Synthesis and biological activities of novel trifluoromethylpyridine amide derivatives containing sulfur moieties.

A series of trifluoromethylpyridine amide derivatives containing sulfur moieties (thioether, sulfone and sulfoxide) was designed and synthesized. Their antibacterial activities against Xanthomonas oryzae pv. oryzae (Xoo), Ralstonia solanacearum (R. solanacearum) and insecticidal activities against P. xylostella were evaluated. Notably, the half-maximal effective concentration (EC50) value of sulfone-containing compound F10 is 83 mg L-1 against Xoo, which is better than that of commercial thiodiazole copper (97 mg L-1) and bismerthiazol (112 mg L-1). Thioether-containing compounds E1, E3, E5, E6, E10, E11 and E13 showed much higher activities against R. solanacearum with the EC50 value from 40 to 78 mg L-1, which are much lower than that of thiodiazole copper (87 mg L-1) and bismerthiazol (124 mg L-1). Generally, most of the sulfone-containing compounds and sulfoxide-containing compounds showed higher activities against Xoo than that of the corresponding thioether-containing compound, but most of the thioether-containing compounds contributed higher antibacterial activities against R. solanacearum. Furthermore, title compounds E3, E11, E24 and G2 showed good insecticidal activities of 75%, 70%, 70% and 75%, respectively.

Emergence of a novel highly pathogenic porcine reproductive and respiratory syndrome virus in China.

From 2014 to 2015, four novel highly pathogenic PRRS virus (HP-PRRSV) strains named 14LY01-FJ, 14LY02-FJ 15LY01-FJ, and 15LY02-FJ were isolated from high morbidity (100%) and mortality (40%-80%) in piglets and sows in Fujian Province. To further our knowledge about these novel virus strains, we characterized their complete genomes and determined their pathogenicity in piglets. Full-length genome sequencing analysis showed that these four isolates were closely related to type 2 (North American type, NA-type) isolates, with 88.1%-96.3% nucleotide similarity, but only 60.6%-60.8% homology to the Lelystad virus (LV) (European type, EU-type). The full length of the four isolates was determined to be 15017 or 15018 nucleotides (nt), excluding the poly(A) tail. Furthermore, the four isolates had three discontinuous deletions (aa 322-432, aa 483, and aa 504-522) within hypervariable region II (HV-II) of Nsp2, as compared to the reference strain VR-2332. This deletion pattern in the four isolates is consistent with strain MN184 and strain NADC30 isolated from America. Phylogenetic and molecular evolutionary analyses indicated that these virulent strains originated from a natural recombination event between the JXA1-like HP-PRRSV (JXA-1 is one of the earliest Chinese HP-PRRSV strains; sublineage 8.7) and the NADC30-like (lineage 1) PRRSV. Animal experiments demonstrated that these four strains caused significant weight loss and severe histopathological lung lesions as compared to the negative control group. High mortality rate (40% or 80%) was found in piglets infected with any one of the four strains, similar to that found with other Chinese HP-PRRSV strains. This study showed that the novel variant PRRSV was HP-PRRSV, and it is therefore critical to monitor PRRSV evolution in China and develop a method for controlling PRRS.

Purification and characterization of chitosanase and Exo-beta-D-glucosaminidase from a Koji mold, Aspergillus oryzae IAM2660.

Chitosan-degrading activity was detected in the culture fluid of Aspergillus oryzae, A. sojae, and A. flavus among various fungal strains belonging to the genus Aspergillus. One of the strong producers, A. oryzae IAM2660 had a higher level of chitosanolytic activity when N-acetylglucosamine (GlcNAc) was used as a carbon source. Two chitosanolytic enzymes, 40 kDa and 135 kDa in molecular masses, were purified from the culture fluid of A. oryzae IAM2660. Viscosimetric assay and an analysis of reaction products by thin-layer chromatography clearly indicated the endo- and exo-type cleavage manner for the 40-kDa and 135-kDa enzymes, respectively. The 40-kDa enzyme, designated chitosanase, catalyzed a hydrolysis of glucosamine (GlcN) oligomers larger than pentamer, glycol chitosan, and chitosan with a low degree of acetylation (0-30%). The 135-kDa exo-beta-D-glucosaminidase,enzyme,named released a single GlcN residue from the GlcN oligomers and chitosan, but did not release GlcNAc residues from either GlcNAc oligomer or colloidal chitin.

Cloning and characterization of a chitosanase gene from the koji mold Aspergillus oryzae strain IAM 2660.

A genomic copy of the gene coding for chitosanase (csnA) was isolated from Aspergillus oryzae IAM 2660. A. oryzae csnA contains an open reading frame that encodes a polypeptide of 245 amino acids with a calculated molecular mass of 26,500 Da. The deduced amino acid sequence of A. oryzae csnA indicates extensive similarities to those of other fungal chitosanases.