Comparing the ability of luminex xMAP(®) salmonella serotyping assay and traditional serotyping method for serotyping salmonella isolated from southern Chinese population.

AIMS: To investigate whether the Luminex xMAP(®) Salmonella Serotyping Assay (xMAP SSA) is applicable to serotype Salmonella from humans in southern China. METHODS AND RESULTS: Two hundred and five Salmonella isolates from diarrhoea patients were serotyped by xMAP SSA in parallel with the traditional serotyping. Forty serotypes were identified among 205 isolates; the most prevalent serotypes identified were Salmonella Enteritidis, Salmonella Stanley, Salmonella I 4,5,12:i:-, and Salmonella Typhimurium. One hundred and ninety-five (95·1%, 195/205) isolates were serotyped completely by xMAP SSA, while 10 stereotypes were partially detected as they were not included in the assay. The xMAP SSA correctly identified 192 (98·5%, 192/195) isolates. Five nonmotile and three monophasic strains, which possessed flagellar antigen genes that weren't expressed, were completely serotyped by xMAP SSA; however, these isolates were left undetected by the traditional method. CONCLUSION: The xMAP SSA used in the study is a microsphere-based, molecular assay that could rapidly and accurately serotype Salmonella. It is suitable to identify the serovars of Salmonella in southern China. SIGNIFICANCE AND IMPACT OF THE STUDY: The xMAP SSA, with high-throughput characteristics, provides an accurate and rapid serotyping system that dramatically strengthens the capability of clinical and public health laboratories for Salmonella serotyping.

Correlation between AS1 gene expression and seed protein contents in different soybean (Glycine max [L.] Merr.) cultivars.

In higher plants, asparagine synthetase (AS) plays an important role in regulating the nitrogen sink-source relationship. We studied the expression of AS genes in five Chinese soybean cultivars exhibiting contrasting seed protein contents. We found that only the AS2 but not the AS1 gene was induced by dark treatment. On the other hand, the expression of AS1 in leaves (especially in trifoliate leaves of young seedlings) showed a positive correlation with seed protein contents in the soybean cultivars tested. Therefore, in spite of the fact that the principle transporting compounds in soybean plants for nitrogen acquired via symbiotic fixation are ureides, AS may still play an important role in the process of nitrogen assimilation.