Genome re-sequencing suggested a weedy rice origin from domesticated indica-japonica hybridization: a case study from southern China.

MAIN CONCLUSION: Whole-genome re-sequencing of weedy rice from southern China reveals that weedy rice can originate from hybridization of domesticated indica and japonica rice. Weedy rice (Oryza sativa f. spontanea Rosh.), which harbors phenotypes of both wild and domesticated rice, has become one of the most notorious weeds in rice fields worldwide. While its formation is poorly understood, massive amounts of rice genomic data may provide new insights into this issue. In this study, we determined genomes of three weedy rice samples from the lower Yangtze region, China, and investigated their phylogenetics, population structure and chromosomal admixture patterns. The phylogenetic tree and principle component analysis based on 46,005 SNPs with 126 other Oryza accessions suggested that the three weedy rice accessions were intermediate between japonica and indica rice. An ancestry inference study further demonstrated that weedy rice had two dominant genomic components (temperate japonica and indica). This strongly suggests that weedy rice originated from indica-japonica hybridization. Furthermore, 22,443 novel fixed single nucleotide polymorphisms were detected in the weedy genomes and could have been generated after indica-japonica hybridization for environmental adaptation.

A multiple regression based method for indirect compensation of hemispherical resonator gyro temperature error.

In order to improve the measuring accuracy of the Hemispherical Resonator Gyro under variable temperature, aiming at the problem of "external temperature is unavailable and internal temperature is unmeasurable," a multiple regression based method is proposed for compensating temperature error in the gyro. The relationship between the internal temperature and the resonant frequency of the gyro is analyzed theoretically. According to a constant temperature experiment, a linear relationship between them is derived based on the least square method. The analysis of a temperature-rising experiment shows that the correlation of the gyro output with the internal temperature is much higher than that with the external temperature. Therefore, taking the resonant frequency as an independent variable, a multiple regression model is established for compensating the temperature error. The compensation effect of the model is verified by temperature-rising and temperature-dropping experiments, which show that the output sequence before compensation is not stable, while it is stable after compensation. After compensation, the drift of the gyro decreases by 62.76% and 48.48%, respectively, and its measuring accuracy becomes equivalent to that at the constant temperature. The experimental results verify the feasibility and effectiveness of the model developed for indirect compensation of temperature error.

[Seroepidemiological survey of Toxoplasma gondii infection in patients with gynecological malignant tumors].

OBJECTIVE: To investigate the seroprevalence of Toxoplasma gondii infection in patients with gynecological malignant tumors, so as to provide the evidence for the control of T. gondii infections in the patients with gynecological malignant tumors. METHODS: A total of 327 patients with gynecological malignant tumors were recruited, and 200 women with normal healthy examinations were served as controls. The serum anti-T. gondii IgG and IgM antibodies were detected by using ELISA, and the seroprevalence was compared between the patients and controls, and among various types of cancers. RESULTS: The overall seroprevalence of T. gondii was 26.91% (88/327) in the patients with gynecological malignant tumors, which was significantly higher than that (5.00%) in the healthy volunteers (χ2 = 39.36, P<0.01) . The prevalence of anti-T. gondii IgG antibody in the cancer patients was significantly higher than that in the controls (26.30% vs. 5.00%; χ2 = 37.79, P<0.01), while the prevalence of anti-T. gondii IgM antibody in the cancer patients was not significantly different from that in the controls (0.92% vs. 0; corrected χ2 = 0.58, P > 0.01) . The positive rates of anti-T. gondii IgG antibody were 27.68%, 25.47% and 25.69% in ovarian cancer, cervical cancer, and breast cancer patients respectively, which were all significantly higher than those in the controls (χ2 = 32.35, 27.32 and 28.00; all P values<0.01); however, there was no significant difference among the various types of cancer patients in the positive rates of anti-T. gondii IgG antibody (χ2 = 0.17, P > 0.05) . In addition, the positive rates of anti-T. gondii IgM antibody were 1.79%, 0 and 0.92% in ovarian cancer, cervical cancer and breast cancer patients respectively, which was not significantly different from those in the controls (all P values > 0.05). CONCLUSIONS: The seroprevalence of T. gondii infection is high in the patients with gynecological malignant tumors. It is suggested that the prevention and control of T. gondii infection should be strengthened in these patients.