Wentao Fan

Immune-enhancing activity of polysaccharides isolated from Atractylodis macrocephalae Koidz

This study evaluated the immune-enhancing activity of polysaccharides from the rhizoma of Atractylodis macrocephalae Koidz (RAMPS) in vitro. Lymphocyte proliferation, cell cycle distribution, and percentages of CD4(+) and CD8(+) cells were determined. Different concentrations of RAMPS were added to peripheral blood T lymphocytes. Results showed that RAMPStp and RAMPS60c could significantly enhance T lymphocyte proliferation individually or synergistically with phytohemagglutinin at most concentrations. The active sites of RAMPStp and RAMPS60c were then selected. Lymphocyte cell cycle distribution and percentages of CD4(+) and CD8(+) cells were determined by flow cytometry. At most time points, RAMPS60c and RAMPStp could promote lymphocytes enter into S and G2/M phases. RAMPStp and RAMPS60c effectively improved the percentages of CD4(+) and CD8(+) T cells. RAMPStp produced optimal effects. Therefore, RAMPStp could be used as a component of novel immunopotentiators.

Oxidative Stress and Hepatocellular Injury Induced by Oral Administration of Cr3+ in Chicken

This study aims to investigate the oxidative stress and hepatocellular injury induced by Cr3+ in chicken. Different doses of CrCl3 solutions (50% LD50, 25% LD50, and 12.5% LD50) and equivalent water were orally administered to chicken. Chicken liver samples were measured for the activities of antioxidant enzymes, the contents of glutathione, total antioxidant capacity (T‐AOC), malondialdehyde (MDA), and hydrogen peroxide to indirectly evaluate the oxidative stress in chicken liver. Results indicated that the oral administration of Cr3+ at high dose significantly increased (P < 0.05) the MDA levels after 28 days of exposure, with decreased T‐AOC, glutathione, and antioxidant enzymes activities. Low and medium doses groups show that T‐AOC, glutathione, and antioxidant enzymes activities increased after 14 days, then decreased gradually, but low and medium groups higher than control group, only high group lower than control group finally. These statistics and histopathological analysis suggest that high dose and long‐term exposure of Cr3+ induce oxidative stress and hepatocellular injury.

Liposomes containing recombinant E protein vaccine against duck Tembusu virus in ducks

To obtain an effective vaccine candidate against duck Tembusu viral (DTMUV) disease which causes egg-drop and great economical loss in the Chinese duck industry, liposome vaccines containing recombinant E protein were prepared and assessed in this study. The recombinant plasmid (PET28a-E) was constructed and transformed into BL21 (DE3) cells to produce E proteins. The recombinant E proteins were purified and entrapped by liposomes through reverse-phase evaporation. Eighty-four cherry valley ducks were randomly divided into seven groups and inoculated intramuscularly at one- or seven-day-old with liposomes-E protein or Freunds adjuvant-E protein vaccine. Blood samples were collected from the first week to the tenth week for serum antibody, plasma for viremia, as well as oropharyngeal and cloacal swabs for virus shedding analyses after being challenged with a 10(2.4) 50% tissue culture infective dose (TCID50) of duck Tembusu virus. Results showed that serum antibody level of the liposomes vaccine was higher than the Freunds adjuvant vaccine, and inoculating twice was superior to once; furthermore, the viremia and virus shedding tests also proved that the liposomes vaccine can provide complete protection against DTMUV challenge. These results demonstrated that the liposomes-E protein vaccine could be used as a potential candidate vaccine to prevent DTMUV infection in ducks.

Structure characterization of three polysaccharides and a comparative study of their immunomodulatory activities on chicken macrophage

In this study, we evaluated structure characterization and immunomodulatory activity of polysaccharides from Astragalus aboriginum Richardson (RAPS), Atractylodes macrocephala Koidz (RAMPS) and Rumia seseloides Hoffm (RSPS) in vitro on chicken macrophage. We found that molecular weight of RAPS and RAMPS was 122.4 and 109.4kDa higher than 64.71kDa of RSPS. Glucose occupied 83.95% and 66.39% in RAPS and RAMPS, respectively. RSPS mainly contained glucose and galacturonic acid, which accounted for 32.35% and 29.25%, respectively. The NMR results displayed that RAPS and RAMPS contained β- glucose, β-galactose, and β-galacturonic acid. The backbone was 1→6 linked glucose. RSPS showed at least six monosaccharide response signals. In vitro experiment, the results showed that RAPS at dosage of 15.62μgmL(-1) exhibited significant immunological on chicken macrophage compared to RAMPS and RSPS. Interestingly, costimulatory molecules levels in RSPS group were higher than that of RAPS, which may associated with the special structure of RSPS.

The immune adjuvant response of polysaccharides from Atractylodis macrocephalae Koidz in chickens vaccinated against Newcastle disease (ND)

Build on our previous research, polysaccharides from the rhizome of Atractylodis macrocephalae Koidz (RAMPS), RAMPStp and RAMPS60c were prepared and the structural characterization and immune response of ND vaccine in chicken were investigated. Immune organ index, Lymphocyte proliferation, antibody titers, cell cycle distribution, and percentages of CD4(+) and CD8(+) cells were determined. GPC analysis showed that the Mn of RAMPS with two peaks were 1.29×10(5) and 1.74×10(3), respectively. GC-MS analysis revealed that RAMPS was composed of glucose, mannose, arabinose, galactose, xylose, d-Ribose and rhamnose, with mass percentages of 66.39%, 21.24%, 5.64%, 2.65%, 2.30%, 1.15% and 0.64%, respectively. NMR spectroscopic analysis demonstrated that a preliminary structure of RAMPS was proposed as 1,3-linked β-d-Galp and 1,6-linked β-d-Galpresidues. In vivo test showed that RAMPStp and RAMPS60c could promote peripheral lymphocytes proliferation and entering into S and G2/M phases, enhance serum HI antibody titer and effectively improve the percentages of CD4(+) and CD8(+) T cells in chickens vaccinated with ND vaccine at most time points. The actions of RAMPStp and RAMPS60c were stronger than that of Lev, and RAMPStp presented the best efficacy. These results indicated that RAMPStp and RAMPS60c characterize of the immune-enhancing activity and RAMPStp possessed the strongest activity. It would be anticipated as a component of new-type immunopotentiator.

Growth performance and oxidative damage in kidney induced by oral administration of Cr(III) in chicken.

This study aimed to evaluate the effects of adding chromic chloride (CrCl3) in the drinking water of chickens. Hyland brown male chickens were randomly divided into four groups. Three groups orally received 1/2 LD50, 1/4 LD50, and 1/8 LD50 CrCl3mgkg(-1) body weight daily for 42d. The fourth group was treated with water. The chickens were sacrificed at 14, 28, and 42d post-treatment. The renal injury was examined through histological analysis, and kidney mass was determined. The effects on growth performance were assessed by measuring the weight of the body, chest muscles, and leg muscles. Oxidative damage was evaluated by determining the antioxidant defense levels in kidney homogenates. The body weight and the weight of tissues gained time-dependently, but significantly decreased compared with those in the control group (P<0.05) at the same exposure time. Administering Cr(3+) significantly increased the levels of malondialdehyde, glutathione, and hydrogen peroxide in the kidney compared with those in the control groups. Whereas, administering Cr(3+) reduced the activities of superoxide dismutase, catalase, glutathione peroxidase, and total an-tioxidant capacity compared with those in the control group (P<0.05) in a dose- and time-dependent manner. In conclusion, oral administration of CrCl3 decreases the growth performance of chickens, leads to the pathological lesions and affects nephritic antioxidant capacity in the kidney dose- and time-dependently.

Characterization of polysaccharides extracted from Platycodon grandiflorus (Jacq.) A.DC. affecting activation of chicken peritoneal macrophages

Polysaccharides were isolated from Platycodon grandiflorus (Jacq.) A.DC. (PG) and the effects of three polysaccharides (PGPS80, PGPS60, PGPSt) on their immunological activities were studied. The structure identification of PGPSs was assessed using physicochemical and spectral methods. Results showed that PGPSt(2.67×105Da) compared to PGPS80(1.01×105Da) and PGPS60(1.12×105Da) has relatively higher average molecular weight(Mw) at the first peak with a narrower molecular weight distribution and all consisted of glucose, mannose, arabinose, galactose, xylose and rhamnose in different mass percentages. PGPS80 and PGPSt linked mainly by 1,3-and 1,6-β-d-Galp residues. The immunological efficacy of PGPSs was performed on chicken peritoneal macrophages. Results showed that PGPSt significantly increased phagocytic rates, proliferation and NO production, stimulated macrophages to produce cytokines, including TNF-α, IL-1β and IL-6 as well as stimulated macrophages to express the maturation markers CD80 and CD86. These findings suggest that PGPSt exerted significant immunological activity and might be associated with special characters.

Analysis of immunostimulatory activity of polysaccharide extracted from Yu-Ping-Feng in vitro and in vivo

As a traditional Chinese multiherbal formula, Yu-Ping-Feng (YPF) is frequently used to treat cold, flu and inflammation-associated diseases. We aimed to evaluate the immunostimulatory effects of polysaccharide isolated from YPF (YPF-PS) in vitro and in vivo. In in vitro experiment, macrophage cell proliferation, phagocytosis rate, cytokine and costimulatory molecule release, T lymphocyte proliferation, cell cycle distribution, CD4+ and CD8+ T cell percentages were determined. To investigate the in vivo effects of YPF-PS treatment, different doses YPF-PS were administered to chicken vaccinated against Newcastle disease. The immune organ index, lymphocyte proliferation, antibody titer, cell cycle distribution, and the cell percentage of CD4+ and CD8+ were assessed. In vitro results indicated that YPF-PS at 15.62μgmL-1 could increase the LPS-induced macrophage cell proliferation and phagocytosis rate significantly. The levels of cytokine (nitric oxide, tumor necrosis factor-alpha, interleukin-1 beta, interleukin-6, and interferon beta) and costimulatory molecules (CD80 and CD86) were also considerably enhanced. Moreover, YPF-PS could significantly enhance T lymphocyte proliferation individually or synergistically with phytohemagglutinin. It promoted lymphocyte entry into S and G2/M phases and increased the percentages of CD4+ and CD8+ T cells effectively. In addition, in vivo experiments showed that YPF-PS could enhance serum HI antibody titer. The results about T lymphocyte proliferation, cell cycle distribution, CD4+ and CD8+ cell percentages in chickens were also confirmed. YPF-PS has efficacious immunomodulatory properties and could be used as a new potential immune stimulator for food and medical purposes.

Virulence in Newcastle disease virus: A genotyping and molecular evolution spectrum perspective

In our research, the molecular evolutions of NDV F and HN genes were analyzed. The phylogenetic analyses of NDV sequences indicated that NDV could be divided into two genotypes: Class I (lentogenic strains) and Class II (velogenic or mesogenic strains). Each genotype possesses high gene homology. Furthermore, the selected pressure analysis showed that the dN/dS of velogenic, mesogenic NDV strains F gene was significantly high and the ω(dN/dS) is 1.1725>1. These results imply that mutations in velogenic, mesogenic NDV F gene are favored by positive natural selection and it has acted to diversify NDV virulence at the nucleotide and amino acid level. We estimated that the subsequent rapid adaptation of the Newcastle disease virus to chickens were likely dependent on a high rate of mutation and the positive selection of mutations in the major F gene.

Analysis of molecular evolution of nucleocapsid protein in Newcastle disease virus

The present study investigated the molecular evolution of nucleocapsid protein (NP) in different Newcastle disease virus (NDV) genotypes. The evolutionary timescale and rate were estimated using the Bayesian Markov chain Monte Carlo (MCMC) method. The p-distance, Bayesian skyline plot (BSP), and positively selected sites were also analyzed. The MCMC tree indicated that NDV diverged about 250 years ago with a rapid evolution rate (1.059 × 10−2 substitutions/site/year) and that different NDV genotypes formed three lineages. The p-distance results reflected the great genetic diversity of NDV. BSP analysis suggested that the effective population size of NDV has been increasing since 2000 and that the basic reproductive number (R0) of NDV ranged from 1.003 to 1.006. The abundance of negatively selected sites in the NP and the mean dN/dS value of 0.07 indicated that the NP of NDV may have undergone purifying selection. However, the predicted positively selected site at position 370 was located in the known effective epitopic region of the NP. In conclusion, although NDV evolved at a high rate and showed great genetic diversity, the structure and function of the NP had been well conserved. However, R0>1 suggests that NDV might have been causing an epidemic since the time of radiation.