Lignin from different biomasses possess biological antioxidation and antimicrobial activities, which depend on the number of functional groups and the molecular weight of lignin. In this work, organosolv fractionation was carried out to prepare the lignin fraction with a suitable structure to tailor excellent biological activities. Gel permeation chromatography (GPC) analysis showed that decreased molecular weight lignin fractions were obtained by sequentially organosolv fractionation with anhydrous acetone, 50% acetone and 37.5% hexanes. Nuclear magnetic resonance (NMR) results indicated that the lignin fractions with lower molecular weight had fewer substructures and a higher phenolic hydroxyl content, which was positively correlated with their antioxidation ability. Both of the original lignin and fractionated lignins possessed the ability to inhibit the growth of Gram-negative bacteria (Escherichia coli and Salmonella) and Gram-positive bacteria (Streptococcus and Staphylococcus aureus) by destroying the cell wall of bacteria in vitro, in which the lignin fraction with the lowest molecular weight and highest phenolic hydroxyl content (L3) showed the best performance. Besides, the L3 lignin showed the ability to ameliorate Escherichia coli-induced diarrhea damages of mice to improve the formation of intestinal contents in vivo. These results imply that a lignin fraction with a tailored structure from bamboo lignin can be used as a novel antimicrobial agent in the biomedical field.

Neospora caninum, an obligate intracellular protozoan parasite, can infect a large variety of vertebrate hosts including the most economically important cattle. Infection with N. caninum is a main cause of abortion in both dairy and beef cattle, which causes great economic losses worldwide. However, the mechanism of host cell infection by N. caninum has not been fully elucidated, especially in terms of inflammatory responses. In this study, the effect of TLR-ERK signaling pathway on the synthesis of pro-inflammatory interleukin-12p40 in mouse peritoneal macrophages (PMϕ) challenged by N. caninum was investigated. Our results suggested that N. caninum infection quickly activated MEK-ERK signaling via TLR11 in PMϕ. In addition, N. caninum infection also caused upregulated production of IL-12p40 by PMϕ, which was significantly reduced with the blockade of TLR11/MEK/ERK pathway, suggesting that this upregulation of IL-12 p40 was TLR11 and MEK-ERK-activation dependent.

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Metorchis orientalis belongs to the genus Metorchis of Opisthorchiidae, which mainly parasitizes in liver and bile ducts of waterfowl, causing liver dysfunction of the host. It has been reported that M. orientalis also infects humans. As a natural species in Australia and a popular ornamental animal, Black Swan ( Cygnus atratus ) has been imported into many countries. At present there has been no report of M. orientalis infection in Black Swan. In the present study M. orientalis infection in Black Swan was identified by a combination of different techniques, including morphological observation and molecular analysis. M. orientalis adults were found in the gallbladder and bile duct of a three-year-old female Black Swan, which was further confirmed by internal transcribed spacer (ITS) sequence analysis. In addition, the intermediate and definitive hosts of M. orientalis from the ‘Qing’ lake (a man-made lake in Changchun, China) that Black Swan lived were investigated and the infection route was preliminarily determined. Parafossarulus striatulus functioned as the first intermediate host which contained M. orientalis DNA, and fishes such as Pseudorasbora parva and Rhodeinae served as the second intermediate hosts with M. orientalis metacercariae in the fish flesh. M. orientalis eggs were found in the feces of three other Swans and six ducks that lived in the ‘Qing’ lake. This was the first reported case about M. orientalis infection of Black Swan. Our study described the course of the infection and provided new information about potential carriers and disseminators of M. orientalis .

Porcine reproductive and respiratory syndrome virus (PRRSV) causes a highly contagious disease and brings huge economic losses to commercial pork production worldwide. PRRSV causes severe reproductive failure in sows and respiratory distress in piglets. To trace the evolution of PRRSV in pigs with respiratory diseases in some regions of China, 112 samples were collected from nine provinces in China during 2016–2018. All samples were detected by RT-PCR and analyzed by the Nsp2/ORF5 (ORF5a)-genes-phylogeny. Sequence analysis and recombination analysis were conducted on the Nsp2/ORF5 (ORF5a) genes of the identified strain in the study. The RT-PCR result shown that the positive rate of PRRSV was 50.89% (57/112). Phylogenetic analysis showed that the identified PRRSV strains were all NA genotype and belonged to lineage 1, 3, and 8. The Nsp2 gene of identified PRRSV strains exhibited nucleotide homologies of 53.0 ~ 99.8%, and amino acid homologies of 46.8 ~ 99.7%. The ORF5 gene of identified PRRSV strains exhibited nucleotide homologies of 82.4 ~ 100%, and amino acid homologies of 79.6 ~ 100%. Sequence analysis revealed that a discontinuous 30-amino-acid deletion (positions 481 and 533–561) and a 131-amino-acid discontinuity deletion (positions 323–433, 481, and 533–551) in Nsp2 of PPRSV isolates; all identified strains in this study may be wild strains, and most identified strains may be highly virulent strains. Sequence analysis of ORF5 and ORF5a revealed that the mutation sites of GP5 were mainly concentrated in the signal peptide and epitopes region, while the mutation sites of ORF5a were mainly concentrated in the transmembrane and the intramembrane region. The recombination analysis indicated that there may be multiple recombination regions in identified strains, and the recombination pattern was more complex. This study showed that the prevalent PRRSV strain in some regions of China was still HP-PRRSV, while NADC30 strain also occupied a certain proportion; different types of PRRSV strains showed different patterns and variation in China. This study suggested that the monitoring of PRRSV prevalence and genetic variation should be further strengthened.

The Apicomplexan parasite Neospora caninum is an obligate intracellular parasitic protozoan. It can cause severe diseases in a number of animals throughout the world. Infection with N. caninum leads to abortions in pregnant animals and neuromuscular disorders of newborns which cause great economic losses to animal husbandry. However, the mechanism of cell invasion by N. caninum is still unclear. This paper aims to investigate the impact of SB203580, a p38 MAPK inhibitor, on host cell invasion by N. caninum. The results suggested the presence of putative p38 MAPK homologues in N. caninum, and incubation of N. caninum with SB203580 markedly reduced the tachyzoite motility and microneme exocytosis (NcMIC2, 3, and 6). Furthermore, treatment or pretreatment of MDBK cells with SB203580 effectively reduced cell invasion by N. caninum. Therefore, SB203580 affected both, parasites and host cells, resulting in inhibition of cell invasion by N. caninum.

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