[Application of near infrared spectral fingerprint technique in lamb meat origin traceability].

Near infrared spectra of 99 lamb meat samples from three pasturing areas and two farming areas of China were scanned and analyzed to seek a cheap, rapid and effective method for lamb meat origin traceability. Two chemometric methods including linear discriminant analysis based on principal component analysis (PCA+LDA) and partial least squares discriminant analysis (PLS-DA) were used to develop the discriminate models. It was showed that there were significantly differences among the lamb meat samples from five regions based on NIR spectra after second derivative (Savitzky-Golay, 9 point) and multiplicative scattering correction (MSC) transformation in the whole wavelength. The discrimination of two models was best for classification of pasturing area and farming area, with both correctly classified by 100%. The correct classification rate of samples from five different regions using PCA+LDA model was 91.2%, higher than using PLS-DA model (76.7%). These results demonstrate that near infrared reflectance spectroscopy (NIRS) combined with chemometric analysis can be used as an effective method to classify lamb meat according to its geographical origin.

[Cloning and characterization of p43 cDNA from Trichinella spiralis].

OBJECTIVE: To clone and characterize the p43 cDNA from muscle larvae cDNA library of Trichinella spiralis (Ts) Chinese isolate. METHODS: PCR technique was used to amplify the target cDNA from muscle larvae cDNA library. After cloned in pMD18T vector, it was transformed into E. coli NovaBlue. The positive clones were sequenced and the cDNA was cloned into pET28a expression vector. After induced by IPTG, the inclusion body of the recombinant protein was purified and re-natured. The deoxyribonuclease II (DNase II) activity of the recombinant protein was tested by hydrolyzing XDNA. RESULTS: Open reading frame (ORF) of the p43 cDNA was successfully cloned from the muscle larvae cDNA library of the Chinese Ts, there were mutations of two nucleotides in the ORF of the Chinese Ts p43 cDNA comparing with that from U.S.A. isolate at the positions 210 and 604, namely, C and A in the USA isolate but T and G in the Chinese isolate. Considering that three authors had cloned the same p43 cDNA from the USA isolate and six groups (including this team) had also obtained the same sequence from the Chinese isolate, the mutation of the two nucleotides was considered as the single nucleotide polymorphic (SNP) marker of the Chinese Ts isolate. The DNase II activity of the recombinant protein was successfully detected by hydrolyzing lamdaDNA. CONCLUSION: The p43 cDNA was successfully cloned from the muscle larvae cDNA library of the Ts Chinese isolate. Two SNPs were found in the nucleotide sequence. The DNase II activity was proved.