The identification and expression analysis of candidate chemosensory genes in the bird cherry-oat aphid Rhopalosiphum padi (L.).

The bird cherry-oat aphid Rhopalosiphum padi (L.) is one of the most important wheat pests with polyphagia and autumn migrants. And, chemosensory genes were thought to play a key role in insect searching their hosts, food and mate. However, a systematic identification of the chemosensory genes in this pest has not been reported. Thus, in this study, we identified 14 odorant-binding proteins, nine chemosensory proteins, one sensory neuron membrane protein, 15 odorant receptors, 19 gustatory receptors and 16 ionotropic receptors from R. padi transcriptomes with a significantly similarity (E-value < 10-5) to known chemosensory genes in Acyrthosiphon pisum and Aphis gossypii. In addition, real-time quantitative polymerase chain reaction (RT-qPCR) was employed to determine the expression profiles of obtained genes. Among these obtained genes, we selected 23 chemosensory genes to analyze their expression patterns in different tissues, wing morphs and host plants. We found that except RpOBP1, RpOBP3, RpOBP4 and RpOBP5, the rest of the selected genes were highly expressed in the head with antennae compared with body without head and antennae. Besides that, the stimulation and depression of chemosensory genes by plant switch indicated that chemosensory genes might be involved in the plant suitability assessment. These results not only provide insights for the potential roles of chemosensory genes in plant search and perception of R. padi but also provide initial background information for the further research on the molecular mechanism of the polyphagia and autumn migrants of it. Furthermore, these chemosensory genes are also the candidate targets for pest management control in future.

Association of interleukin 1B gene polymorphism and gastric cancers in high and low prevalence regions in China.

AIM: Our aim was to study the relationship between interleukin 1B (IL-1B) polymorphism, Helicobacter pylori infection, and gastric cancer in high prevalent (Shanxi) and low prevalent (Guangdong) regions in China. METHOD: Genomic DNA was extracted from peripheral blood of 192 healthy volunteers, 84 gastric cancer patients from Guangdong and 169 healthy volunteers, and 86 gastric cancer patients from Shanxi. Polymorphisms in IL-1B that encodes IL-1beta and IL-1RN that encodes IL-1 receptor antagonist were analysed by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). These polymorphic sites include promoter regions of IL-1B at positions +3954, -511 (C-T transition), and -31 (T-C transition), and IL-1RN variable tandem repeats. RESULTS: In the low prevalence region, the frequencies of the IL-1B +3954 T/T and IL-1RN *2/*2 genotypes were similar. IL-1B -511T/T genotype frequency was significantly higher among patients with gastric cancer (25.0%) than control subjects (12.5%) (chi2=6.7, p=0.01). In the high prevalence region, the frequencies of the IL-1B +3954T/T and -511T/T genotypes and the IL-1RN *2/*2 genotype in the cancer and control groups were similar. IL-1B -31C/C genotype frequency was significantly higher among patients with gastric cancer (90.0%) than controls (78.0%) (chi2=5.0, p=0.025). Compared with the low prevalence region, control subjects from the high prevalence region had a higher frequency of the IL-1B -511T/T genotype (23.0% v 12.5%; chi2=7.0, p<0.008). While H pylori infection alone had only a modest effect on the risk of gastric cancer development (odds ratio (OR) 5.0 (95% confidence interval (CI) 1.5-16.3)), combined with the IL-1B -511T/T genotype the risk was markedly elevated (OR 17.1, 95% CI 3.8-76.4). CONCLUSION: IL-1B -511T/T genotypes are associated with gastric cancer in China. The effect of IL-1B polymorphism is less obvious in areas of high prevalence for gastric cancer.