Objective To screen stage\|specific expression genes of plerocercoid of Spirometra erinacei\|europaei. Methods RNA was extracted by the acid guanidinium thiocyanate\|phenol\|chloroform from plerocercoid and adult worm of Spirometra erinacei\|europaei. Contaminated DNA in the RNA was digested by RNase\|free DNase. cDNA was synthesized by using T\-\{12\}MA, T\-\{12\}MC, T\-\{12\}MG and T\-\{12\}MT primers, and PCR was then done using the same T\-\{12\}MN and one random primers. The PCR products were fractionated on 8% denatured polyacrylamide gel, differential bands of plerocercoid found in the gel were cut out, amplified by PCR and sequenced after the gel was dried out and autoradiographed. Northern hybridization was conducted to identify the stage\|specific expression genes. Results Eleven differential bands were selected from the gel and classified into 3 kinds of gene fragments by hybridization after they were amplified by PCR. The fragments 1 and 2 were confirmed to express specifically in plerocercoid by Northern hybridization, but the fragment 3 was expressed in both plerocercoid and adult worm. When the 3 gene fragments were homologically analyzed in GenBank, the sequence which was homologous with the fragments 1 and 2 was not found, but the fragment 3 had high homology with many kinds of 28S rRNA. Conclusion The gene expression of plerocercoid was different from that of adult worm probably because they live in different hosts. Two kinds of different gene fragments in plerocercoid were identified by mRNA differential display technique.

Excessive salt intake is an important risk factor of diseases such as hypertension, stroke, and stomach cancer. China is one of countries with high salt intake in the world. Recently, the intake of sodium from pre-packaged foods in China has been increasing, and the situation of salt control is rigorous. Based on the summary of the domestic and international experience of salt reduction, the "Guidelines for Salt Reduction in Chinese Food Industry" presents the basic principles, targets at different stages within various categories, technical routes, steps and measures, and social environment co-construction of salt reduction in Chinese food industry. This article focuses on the background, basis, process, key content and promotion of the guideline. The implementation of this guideline will contribute to the vigorous advancement of salt reduction action in Chinese food industry.