[Quantitative analysis of goose and duck mixed down using visible/NIR spectroscopy].

Goose down and duck down have very similar appearance but the quality of goose down is better than that of duck down in general. There is a highest allowable limit as specified by the various national standards of feather and down for the percentage of duck feather or down mixed in goose feather or down. Traditional detection method, manual inspection with a high-scale microscope, is labor intensive and not suitable for large-volume samples analysis and on-site rapid testing. In the present paper, visible/near-infrared (NIR) spectroscopy combined with successive projection algorithm (SPA) for characteristic wavelengths selection was used to determinate the content of duck down mixed in goose down. In the range of 450-930 nm, the multiple linear regression (MLR) model established with the 8 characteristic wavelengths selected by SPA achieved good prediction, the correlation coefficient of 0.983, root mean square error of calibration (RMSEC) of 5.44%, and root mean square error of prediction (RMSEP) of 5.75%. Therefore, it is expected to be used for rapid detection of feather and down quality in future.

Nitric oxide inducing function and intracellular movement of chicken interleukin-18 in cultured cells.

To evaluate the characteristics of chicken interleukin-18 (ChIL-18) in different forms in vitro, the ChIL-18 full-length gene (ChIL-18-F) and the ChIL-18 presumed mature protein gene (ChIL-18-M) were cloned and inserted into the eukaryotic expression vector pCI, to construct recombinant pCI-ChIL-18-F and pCI-ChIL-18-M. The recombinant plasmids were then transferred into chicken splenic lymphocytes (CSLs). Western blot showed that ChIL-18-F, with a molecular weight of 23.0 kDa, was produced in CSLs transfected by pCI-ChIL-18-F; ChIL-18-M, with a molecular weight of 19.5 kDa, was produced in CSLs transfected by pCI-ChIL-18-M. The nitric oxide (NO) level in the transfected CSLs and the culture medium at different time points was further examined under confocal microscopy using 4,5-diaminofluorescein staining. The results showed that both pCI-ChIL-18-F and pCI-ChIL-18-M groups showed significant increase in intracellular and extracellular NO production compared with pCI transfected control cells. These results suggest that both ChIL-18-F and ChIL-18-M could stimulate NO secretion in CSLs. To characterize the intracellular distribution of ChIL-18, ChIL-18-F and ChIL-18-M were each fused to the enhanced green fluorescent protein gene, and expressed in Vero cells. The results showed that the ChIL-18-F tended to the membranous region in Vero cells, while ChIL-18-M did not. This indicates that the N-terminal 27 amino acid peptide helped ChIL-18 target to Vero cell membranes.

Synthesis of reassortant infectious bursal disease virus in chickens injected directly with infectious clones from different virus strains.

The infectious bursal disease virus (IBDV), a member of the Birnaviridae family, containing a bisegmented double-stranded RNA genome, encodes four structural viral proteins, VP1, VP2, VP3, and VP4, as well as a non-structural protein, VP5. In the present paper, the segment A from two IBDV strains, field isolate ZJ2000 and attenuated strain HZ2, were inserted into one NaeI site by site-directed silent mutagenesis and subcloned into the eukaryotic expression plasmid pCI under the control of the human cytomegalovirus (hCMV) immediate early enhancer and promoter to construct the recombinant plasmids pCI-AKZJ2000 and pCI-AKHZ2, respectively. Each of the two recombinants was combined with another recombinant pCI plasmid containing the marked segment B of strain HZ2 (pCI-mB), and injected intramuscularly into non-immunized chickens. Two chimeric IBDV strains were recovered from the chickens. Two out of eight chickens in each of two groups showed the bursal histopathological change. The reassortant virus derived from pCI-AKZJ2000/pCI-mB can infect chicken embryos and shows relatively low virulence. We have developed a novel virus reverse genetic approach for the study of IBDV. The results also form the basis for investigating the role of VP1 in viral replication and pathogenecity.