Association of MHC class-III gene polymorphisms with ER-positive breast cancer in Chinese Han population.

Polymorphisms of the major histocompatibility complex (MHC) have been linked to many diseases, especially autoimmune disorders. Previous studies have shown that genetic variants in MHC class III are associated with breast cancer. To determine if there is an association between MHC class III and breast cancer risk in the Chinese Han population, we carried out a hospital-based case-control study in Guangdong and Jiangsu Provinces, including 216 histologically confirmed breast cancer patients and 216 healthy controls. Nine SNP markers distributed in the class III-coding region were detected using the Sequenom MassARRAY(®) iPLEX System. Deviation from Hardy-Weinberg equilibrium was observed for seven SNPs. There was no significant association between these seven SNP variants and breast cancer in these Chinese women (unconditional logistic regression analysis). However, chr6_31697494 at BAT2, one of the seven SNPs, was found to be significantly associated with both ER- and PR-positive breast cancer. In addition, both chr6_31911109 at C6orf48 and chr6_31975605 at ZBTB12, another two of the seven SNPs, show relevance with ER-positive breast cancer. In conclusion, this is the first evidence that genetic polymorphisms in the MHC class III region are significantly associated with ER-positive breast cancer in the Han Chinese population.

First Report of Paulownia Witches'-Broom Phytoplasma in China.

Paulownia witches'-broom (PaWB) is one of the most important diseases affecting Paulownia tomentosa trees in China. According to 2006 statistics, the disease has affected 880,000 ha of trees for timber production causing billions of dollars in economic losses. During the spring and summer of 2006, a survey was done in Shaanxi Province to confirm phytoplasma infection of paulownia trees exhibiting symptoms of witches'-broom, stunting, yellowing, and proliferating secondary shoots. Foliage samples were collected from 24 symptomatic and 8 symptomless paulownia plants in eight different production fields. Total DNA was extracted from 0.5 g of leaf midrib and stem phloem tissue with a modified cetyltrimethylammoniumbromide (CTAB) method (3). Resulting DNA extracts were analyzed by a nested PCR assay using phytoplasma 16S rRNA gene primer pairs R16mF2/R16mR1 followed by R16F2n/ R16R2 (1), which amplified a 1.4-kb and a 1.2-kb product, respectively, from symptomatic plants. Restriction fragment length polymorphism (RFLP) analysis of the nested 1.2-kb 16S rDNA products with AluI, MseI, HhaI, HpaI, RsaI, BfaI, HinfI, and TaqI endonuclease (2) indicated that all symptomatic plants were infected by a phytoplasma belonging to aster yellows group (16SrI) subgroup D (16SrI-D) phytoplasma strains. A 1.2-kb 16S rDNA sequence (GenBank Accession No. DQ851169) derived from representative strain PaWB-Shaanxi was identical (100%) to that of PaWB phytoplasma (L27033), a known subgroup 16SrI-D strain from Taiwan (2). The agreement between the RFLP analysis and sequence data confirms that PaWB from Shaanxi is a member of subgroup 16SrI-D. To our knowledge, this is the first report of PaWB disease being present in China and of its association with the 16SrI-D subgroup. References: (1) D. E. Gundersen and I.-M. Lee. Phytopathol. Mediterr. 35:144, 1996. (2) I.-M. Lee et al. Inst. J. Syst. Bacteriol. 48:1153, 1998. (3) Y. Qi et al. Biotechnol. Bull. 4:44, 2004.

Sexual development and the effects of active immunization against GnRH in Chinese Tanyang ram lambs.

Tanyang is one of the most important sheep breeds in the northwest of China. However, there is no detailed data on sexual development and timing of puberty/sexual maturity of this breed. This experiment was designed to study the relationships between growth rate and sexual development by measuring body weight, testis diameter, and plasma testosterone concentrations, and observing sexual behavior through puberty from 3 to 8 months old of entire Tanyang ram lambs. At same time, to assess the potential efficacy and welfare benefits of non-surgical castration, the effect of active immunization against gonadotrophin-releasing hormone (GnRH) on sexual development and growth rate on ram lambs was evaluated, and compared with surgically castrated and entire lambs. The results showed that body weight increased at a constant rate from 3 to 8 months old of age. Testis diameter increased rapidly between 3 and 5 months, followed by a period of slow growth. Plasma testosterone concentrations increased sharply from 3 to 6 months of age (P<0.05), after which there were no significant changes from 6 to 8 months of age. Sexual behavior started from 5 months of age. After ram lambs were immunized against GnRH at 3 months of age, there was no increase in testis diameter in the first 4 months after immunization. Plasma testosterone concentrations remained at similar levels to surgically castrated lambs until 6 months of age, and the onset of sexual behavior was delayed, compared with entire ram lambs. GnRH immunization and surgical castration had no significant effect on the body weight by the end of this experiment. These results suggest that 4-5 months of age is a critical period for pubertal changes and testosterone plays an important role in the initiation of puberty and sexual maturity of Tanyang ram lambs in China. In addition, a single shot GnRH immunization at 3 months, acting as an alternative to surgical castration, is a practical method for Chinese Tanyang ram lambs, and provides animal welfare benefits.