Genetic variants at 14q24.1 and breast cancer susceptibility: a fine-mapping study in Chinese women

A single nucleotide polymorphism (SNP) rs999737 at 14q24.1 was identified as a susceptibility marker of breast cancer in a genome-wide association study of the European population, which was also confirmed by some of the following studies in populations of European descent. However, rs999737 is very rare or nonpolymorphic in non-Europeans including Chinese, and the role of other genetic variants at 14q24.1 has not been evaluated in populations of non-European descent. In this study, we first selected 21 common tagging SNPs (minor allele frequency [MAF] >0.05 in the Chinese population) by searching the Hapmap database, covering a linage disequilibrium region of more than 70?Kb at 14q24.1, and then conducted a two-stage study (stage I: 878 cases and 900 controls; stage II: 914 cases and 967 controls) to investigate the associations between these tagging SNPs and risk of breast cancer in a Chinese population. In stage I, two SNPs (rs2842346 and rs17828907) were identified to be significantly associated with breast cancer risk (p=0.030 and 0.027 for genotype distributions, respectively). However, no significant associations were found between these two SNPs and breast cancer risk in either stage II or the combined dataset. These findings suggest that common variants at 14q24.1 might not be associated with the risk of breast cancer in the Chinese population, which will need the replication in additional larger studies.     

Polymorphisms of the myostatin gene and its relationship with reproduction traits in the bian chicken

Myostatin, or growth and differentiation factor 8, is a member of the transforming growth factor-β superfamily; it functions as a negative regulator of skeletal muscle development and growth in mammals. In this study, single nucleotide polymorphisms in the 5' regulatory region and exon 1 of the myostatin gene were detected by PCR-SSCP in the Bian, Jinghai, Youxi, and Arbor Acre chickens, and the associations of the polymorphisms with reproduction traits were analyzed. Seven SNPs (A326G, C334G, C1346T, G1375A, A1473G, G1491A, and G2283A) were found in the myostatin gene. Association analysis showed that the G2283A were significantly associated with reproduction traits. Bian chickens of the GG genotype had a greater age at first egg than those of the GA and AA genotypes (P?相似文献   

Ultrastructural immunolocalization of dentin matrix protein 1 on Sharpey's fibers in monkey tooth cementum

Despite the importance of dentin matrix protein 1 (DMP1) in the formation of mineralized tissue, including dentinogenesis and osteogenesis, its precise role in cementogenesis remains to be clarified fully. The purpose of our study was to demonstrate the ultrastructural immunolocalization of DMP1 in monkey molar tooth cementum. Japanese Macaca fuscata monkeys were fixed by perfusion. The upper molar teeth and accompanying periodontium then were dissected and demineralized with EDTA. Cryosections were obtained, incubated in anti-DMP1 polyclonal antibody, and processed by immunoperoxidase and immunogold labeling. Intense immunoperoxidase staining for DMP1 was observed in acellular extrinsic fiber cementum, particularly in Sharpey's fibers. Cementocyte lacunae with canaliculi showed DMP1 staining in the apical region of the tooth root. Electron immunomicroscopy revealed the close proximity of DMP1 to collagen fibrils in Sharpey's fibers at the mineralization front. Intense immunogold labeling was localized on the walls of the cementocyte lacunae in cellular cementum. These results should contribute to better understanding of the role of DMP1, not only in Sharpey's fiber biomineralization, but also in the maintenance of the cementocyte lacunar space in cementum.     

Establishing epithelial glandular polarity: interlinked roles for ARF6, Rac1, and the matrix microenvironment

Epithelial cysts comprise the structural units of the glandular epithelium. Although glandular inversion in epithelial tumors is thought to be a potential mechanism for the establishment of metastatic disease, little is known about the morphogenic cues and signaling pathways that govern glandular polarity and organization. Using organotypic cultures of Madin-Darby canine kidney cells in reconstituted basement membrane, we show that cellular depletion of the small GTP-binding protein ARF6 promotes the formation of inverted cysts, wherein the apical cell membrane faces the cyst exterior, and the basal domain faces the central lumen, while individual cell polarity is maintained. These cysts are also defective in interactions with laminin at the cyst–matrix interface. This inversion of glandular orientation is accompanied by Rac1 inactivation during early cystogenesis, and temporal activation of Rac1 is sufficient to recover the normal cyst phenotype. In an unnatural collagen I microenvironment, ARF6-depleted, inverted epithelial cysts exhibit some loss of cell polarity, a marked increase in Rho activation and Rac1 inactivation, and striking rearrangement of the surrounding collagen I matrix. These studies demonstrate the importance of ARF6 as a critical determinant of glandular orientation and the matrix environment in dictating structural organization of epithelial cysts.     

High-throughput screening for anti-influenza A virus drugs and study of the mechanism of procyanidin on influenza A virus-induced autophagy

In this research, we have established a high-throughput screening (HTS) platform based on the influenza A virus (IAV) vRNA promoter. Using this HTS platform, we selected 35 medicinal plants out of 83 examples of traditional Chinese medicine and found that 7 examples had not been reported. After examining many previous reports, we found that Vaccinium angustifolium Ait., Vitis vinifera L, and Cinnamomum cassia Presl had a common active compound, procyanidin, and then determined the anti-IAV effect of procyanidin and explored its mechanism of action. With a plaque inhibition assay and a time-of-addition experiment, we found that procyanidin could inhibit the IAV replication at several stages of the life cycle. In the Western blot and EGFP-LC3 localization assays, we found that procyanidin could inhibit the accumulation of LC3II and the dot-like aggregation of EGFP-LC3. In the RT-PCR and Western blot assays, we found procyanidin could inhibit the expression of Atg7, Atg5, and Atg12. Finally, by the bimolecular fluorescence complementation-fluorescence resonance energy transfer and co-immunoprecipitation assays, we found that procyanidin could inhibit the formation of the Atg5-Atg12/Atg16 heterotrimer and the dissociation of the beclin1/bcl2 heterodimer. In conclusion, we have established an HTS platform and identified procyanidin as a novel and promising anti-IAV agent.     

Characterization of the Hormone and Stress-Induced Expression of <Emphasis Type="Italic">FaRE</Emphasis>1 Retrotransposon Promoter in Strawberry

Retrotransposons are the most abundant mobile elements in the plant genome and seem to play an important role in genome reorganization induced by environmental challenges. Their success in this function depends on the ability of their promoters to regulate plant adaptation to biotic and abiotic stresses. In this study, the promoter region of FaRE1 was amplified in the strawberry genome, and promoter::GUS fusion was constructed. We produced transgenic strawberry plants carrying FaRE1 promoter::GUS-fusion genes, and monitored GUS reporter activity. Histochemical and fluorimetric GUS analysis these plants showed the characteristics of the FaRE1 promoter were activated by either hormones treatments with ABA, NAA, and 2,4-D or cold stress. In addition, we found the GUS reporter was activated in the leaves of transgenic strawberry plants using 5-azaC. These results suggest that the promoter of FaRE1 may act as different signal transduction pathways, allowing FaRE1 retrotransposon to be activated in response to multiples challenges.     

A Novel Immunodiagnostic Assay to Detect Serum Antibody Response against Selected Soluble Egg Antigen Fractions from Schistosoma japonicum

Background

Schistosomiasis japonica remains a real threat to public health in China. The currently used immunodiagnostic assays are sensitive and have a certain degree of specificity, however, they all use complex crude antigens, are based on detection of schistosome-specific antibodies, and have been shown to cross-react with other parasitic diseases. Therefore, these assays cannot be used to evaluate chemotherapy efficacy. The development of highly sensitive and highly specific immunodiagnostic techniques that can monitor the decline of antibodies specific for S. japonica will be extremely valuable as part of the ongoing strategy to control schistosomiasis in endemic areas. Here we report on the identification of unique fraction antigens of soluble egg antigen (SEA) to which the antibodies disappear 7 weeks after effective treatment. Furthermore, we use these SEA fractions to develop a modified assay with both high sensitivity and specificity.

Methodology/Principal Findings

SEA of S. japonicum was fractionated by electrophoresis using 7.5% SDS-PAGE under non-reducing conditions. The SEA fraction antigens to which antibodies were decreased soon after treatment were collected and used as the detection antigens to establish the FA-ELISA. Sera from patients with acute and chronic schistosomiasis infection, healthy people, and those with other parasitic diseases, were used to evaluate their sensitivity and specificity. Furthermore, sera from patients with chronic schistosomiasis infection were evaluated before and after treatment at different time points to evaluate their chemotherapeutic efficacy.

Conclusion/Significance

We demonstrated that this novel FA-ELISA provided high sensitivity and specificity, with very low cross-reactivity, and can serve as an effective tool to determine the efficacy of chemotherapy against S. japonicum.     

Analysis of autophagy genes in microalgae: chlorella as a potential model to study mechanism of autophagy

Background

Microalgae, with the ability to mitigate CO₂ emission and produce carbohydrates and lipids, are considered one of the most promising resources for producing bioenergy. Recently, we discovered that autophagy plays a critical role in the metabolism of photosynthetic system and lipids production. So far, more than 30-autophagy related (ATG) genes in all subtypes of autophagy have been identified. However, compared with yeast and mammals, in silico and experimental research of autophagy pathways in microalgae remained limited and fragmentary.

Principal Findings

In this article, we performed a genome-wide analysis of ATG genes in 7 microalgae species and explored their distributions, domain structures and evolution. Eighteen “core autophagy machinery” proteins, four mammalian-specific ATG proteins and more than 30 additional proteins (including “receptor-adaptor” complexes) in all subtypes of autophagy were analyzed. Data revealed that receptor proteins in cytoplasm-to-vacuole targeting and mitophagy seem to be absent in microalgae. However, most of the “core autophagy machinery” and mammalian-specific proteins are conserved among microalgae, except for the ATG9-cycling system in Chlamydomonas reinhardtii and the second ubiquitin-like protein conjugation complex in several algal species. The catalytic and binding residues in ATG3, ATG5, ATG7, ATG8, ATG10 and ATG12 are also conserved and the phylogenetic tree of ATG8 coincides well with the phylogenies. Chlorella contains the entire set of the core autophagy machinery. In addition, RT-PCR analysis verified that all crucial ATG genes tested are expressed during autophagy in both Chlorella and Chlamydomonas reinhardtii. Finally, we discovered that addition of 3-Methyladenine (a PI3K specific inhibitor) could suppress the formation of autophagic vacuoles in Chlorella.

Conclusions

Taken together, Chlorella may represent a potential model organism to investigate autophagy pathways in photosynthetic eukaryotes. The study will not only promote understanding of the general features of autophagic pathways, but also benefit the production of Chlorella-derived biofuel with future commercial applications.     

Metagenomic insights into the fibrolytic microbiome in yak rumen

The rumen hosts one of the most efficient microbial systems for degrading plant cell walls, yet the predominant cellulolytic proteins and fibrolytic mechanism(s) remain elusive. Here we investigated the cellulolytic microbiome of the yak rumen by using a combination of metagenome-based and bacterial artificial chromosome (BAC)-based functional screening approaches. Totally 223 fibrolytic BAC clones were pyrosequenced and 10,070 ORFs were identified. Among them 150 were annotated as the glycoside hydrolase (GH) genes for fibrolytic proteins, and the majority (69%) of them were clustered or linked with genes encoding related functions. Among the 35 fibrolytic contigs of >10 Kb in length, 25 were derived from Bacteroidetes and four from Firmicutes. Coverage analysis indicated that the fibrolytic genes on most Bacteroidetes-contigs were abundantly represented in the metagenomic sequences, and they were frequently linked with genes encoding SusC/SusD-type outer-membrane proteins. GH5, GH9, and GH10 cellulase/hemicellulase genes were predominant, but no GH48 exocellulase gene was found. Most (85%) of the cellulase and hemicellulase proteins possessed a signal peptide; only a few carried carbohydrate-binding modules, and no cellulosomal domains were detected. These findings suggest that the SucC/SucD-involving mechanism, instead of one based on cellulosomes or the free-enzyme system, serves a major role in lignocellulose degradation in yak rumen. Genes encoding an endoglucanase of a novel GH5 subfamily occurred frequently in the metagenome, and the recombinant proteins encoded by the genes displayed moderate Avicelase in addition to endoglucanase activities, suggesting their important contribution to lignocellulose degradation in the exocellulase-scarce rumen.