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991.
Wu K Jiao X Li Z Katiyar S Casimiro MC Yang W Zhang Q Willmarth NE Chepelev I Crosariol M Wei Z Hu J Zhao K Pestell RG 《The Journal of biological chemistry》2011,286(3):2132-2142
The cell fate determination factor Dachshund was cloned as a dominant inhibitor of the hyperactive epidermal growth factor receptor ellipse. The expression of Dachshund is lost in human breast cancer associated with poor prognosis. Breast tumor-initiating cells (TIC) may contribute to tumor progression and therapy resistance. Here, endogenous DACH1 was reduced in breast cancer cell lines with high expression of TIC markers and in patient samples of the basal breast cancer phenotype. Re-expression of DACH1 reduced new tumor formation in serial transplantations in vivo, reduced mammosphere formation, and reduced the proportion of CD44(high)/CD24(low) breast tumor cells. Conversely, lentiviral shRNA to DACH1 increased the breast (B)TIC population. Genome-wide expression studies of mammary tumors demonstrated DACH1 repressed a molecular signature associated with stem cells (SOX2, Nanog, and KLF4) and genome-wide ChIP-seq analysis identified DACH1 binding to the promoter of the Nanog, KLF4, and Lin28 genes. KLF4/c-Myc and Oct4/Sox2 antagonized DACH1 repression of BTIC. Mechanistic studies demonstrated DACH1 directly repressed the Nanog and Sox2 promoters via a conserved domain. Endogenous DACH1 regulates BTIC in vitro and in vivo. 相似文献
992.
Gong P Zhang J Cao L Nan Z Li J Yang J Fang H Jiao H Jiang T Su L Zhang X 《Experimental parasitology》2011,(4):784-788
To investigate the presence of myeloma-associated antigens in Trichinella spiralis and their anti-tumor effect, cross-immune responses between antigens of the myeloma cell SP2/0 versus positive sera to T. spiralis, and antigens of T. spiralis versus positive sera to myeloma cell SP2/0 were determined using T. spiralis and myeloma specific enzyme-linked immunosorbent assays (ELISA). The myeloma-associated antigens in T. spiralis were separated by ultrafiltration and 2-D electrophoresis, and the amino acid sequences and molecular weights were determined by spectrometry. An obvious reaction was found between a 33 kDa antigen and positive sera, and the major component of the antigen was tropomyosin (TM), which is an surface acidic protein with 284 amino acids. Mice were immunized with TM to determine the anti-tumor effect in vivo. The results showed that CD4+, CD8+ T lymphocyte, and CD19+ B lymphocyte were significantly increased (P < 0.05). The anti-tumor effects were significantly different between mice immunized with the antigens or adjuvant alone (P < 0.05), while the difference between mice immunized with antigens and whole T. spiralis was not significant (P > 0.05). The results indicated that TM identified in this study may play a role in eliciting cross-protective immunity. 相似文献
993.
Responses of aerobic anoxygenic phototrophic bacteria to algal blooms in the East China Sea 总被引:1,自引:0,他引:1
Aerobic anoxygenic phototrophic bacteria (AAPB) are a new functional group of heterotrophic bacteria capable of phototrophy,
and are suggested to be closely related with phytoplankton. However, less known is the relationship between AAPB and dominant
phytoplankton populations. In this tudy, the responses of AAPB to algal blooms (ABs) in the AB-frequent-occurrence area of
the East China Sea were investigated during four cruises from March to June 2005, using an advanced ‘Time-series observation-based
cyanobacteria-calibrated InfraRed Epifluorescence Microscopy (TIREM)’ approach. Generally, total bacterial abundances at the
bloom stations were higher than or similar to those at the non-bloom stations during the same time period. Interestingly,
the responses of AAPB to ABs seemed to be more diverse and complex. AAPB abundance was higher at the stations with ABs where
Thalassiosira curviseriata Takano and Skeletonema costatum (Greville) Cleve, Noctiluca scintillans (Macartney) Kofoid et Swezy, or Prorocentrum donghaiense Lu and Karenia mikimotoi Hansen co-dominated than those at the non-bloom stations during the same time period. However at the stations with a bloom
of Akashiwo sanguinea Hansen, AAPB abundance only accounted for ~20% of the average abundance of AAPB at the non-bloom stations. In addition, variations
of AAPB’s proportion to total bacterial abundance (AAPB%) in response to ABs basically followed AAPB abundance. Overall, our
results suggest that the responses of AAPB to ABs are AB-species specific and somewhat independent of chlorophyll a concentration. 相似文献
994.
NBS-LRR (nucleotide-binding site-leucine-rich repeat), LRR-RLK (LRR-receptor-like kinase), and LRR-only are the three major LRR-encoding genes. Owing to the crucial role played by them in plant resistance, development, and growth, extensive studies have been performed on the NBS-LRR and LRR-RLK genes. However, few studies have focused on these genes collectively; they may co-vary as all of them contain LRR motifs. To investigate their common evolutionary patterns, all major classes of LRR-encoding genes were identified in 12 plant species, and particularly compared in two pairs of close relatives, Arabidopsis thaliana-A. lyrata (At-Al) and Zea mays-Sorghum bicolor. Our results showed that these genes co-vary significantly in terms of their numbers between species and that the genes with certain evolutionary parameters are most likely to have similar functions. The development-related genes have clear orthologous relationships between closely related species, as well as lower nucleotide divergence, and Ka/Ks ratio. In contrast, resistance-related genes have exactly opposite characteristics and favor 11-15 LRRs per gene. This association could be very useful in predicting the function of LRR-encoding genes. The presence of co-variation suggests that LRRs, combined with other domains, can work better in some common functions. In order to cooperate efficiently, there should be balanced gene numbers among the different gene classes. 相似文献
995.
Community Structure and Function of Planktonic Crenarchaeota: Changes with Depth in the South China Sea 总被引:1,自引:0,他引:1
Marine Crenarchaeota represent a widespread and abundant microbial group in marine ecosystems. Here, we investigated the abundance,
diversity, and distribution of planktonic Crenarchaeota in the epi-, meso-, and bathypelagic zones at three stations in the
South China Sea (SCS) by analysis of crenarchaeal 16S rRNA gene, ammonia monooxygenase gene amoA involved in ammonia oxidation, and biotin carboxylase gene accA putatively involved in archaeal CO2 fixation. Quantitative PCR analyses indicated that crenarchaeal amoA and accA gene abundances varied similarly with archaeal and crenarchaeal 16S rRNA gene abundances at all stations, except that crenarchaeal
accA genes were almost absent in the epipelagic zone. Ratios of the crenarchaeal amoA gene to 16S rRNA gene abundances decreased ~2.6 times from the epi- to bathypelagic zones, whereas the ratios of crenarchaeal
accA gene to marine group I crenarchaeal 16S rRNA gene or to crenarchaeal amoA gene abundances increased with depth, suggesting that the metabolism of Crenarchaeota may change from the epi- to meso- or
bathypelagic zones. Denaturing gradient gel electrophoresis profiling of the 16S rRNA genes revealed depth partitioning in
archaeal community structures. Clone libraries of crenarchaeal amoA and accA genes showed two clusters: the “shallow” cluster was exclusively derived from epipelagic water and the “deep” cluster was
from meso- and/or bathypelagic waters, suggesting that niche partitioning may take place between the shallow and deep marine
Crenarchaeota. Overall, our results show strong depth partitioning of crenarchaeal populations in the SCS and suggest a shift
in their community structure and ecological function with increasing depth. 相似文献
996.
Marine group I Crenarchaeota (MGI) represents a ubiquitous and numerically predominant microbial population in marine environments. An understanding of the spatial dynamics of MGI and its controlling mechanisms is essential for an understanding of the role of MGI in energy and element cycling in the ocean. In the present study, we investigated the diversity and abundance of MGI in the East China Sea (ECS) by analysis of crenarchaeal 16S rRNA gene, the ammonia monooxygenase gene amoA, and the biotin carboxylase gene accA. Quantitative PCR analyses revealed that these genes were higher in abundance in the mesopelagic than in the euphotic zone. In addition, the crenarchaeal amoA gene was positively correlated with the copy number of the MGI 16S rRNA gene, suggesting that most of the MGI in the ECS are nitrifiers. Furthermore, the ratios of crenarchaeal accA to amoA or to MGI 16S rRNA genes increased from the euphotic to the mesopelagic zone, suggesting that the role of MGI in carbon cycling may change from the epipelagic to the mesopelagic zones. Denaturing gradient gel electrophoretic profiling of the 16S rRNA genes revealed depth partitioning in MGI community structures. Clone libraries of the crenarchaeal amoA and accA genes showed both "shallow" and "deep" groups, and their relative abundances varied in the water column. Ecotype simulation analysis revealed that MGI in the upper ocean could diverge into special ecotypes associated with depth to adapt to the light gradient across the water column. Overall, our results showed niche partitioning of the MGI population and suggested a shift in their ecological functions between the euphotic and mesopelagic zones of the ECS. 相似文献
997.
通过RT-PCR从经ConA刺激诱导的奶牛脾脏淋巴细胞总RNA中扩增出牛γ干扰素 (BoIFN-γ) cDNA,克隆到真核载体pVAX1中,测序结果显示pVAX1中的插入序列BoIFN-γ基因与已报道序列一致。用重组质粒pVAX1-BoIFN-γ转染COS-7细胞并进行间接免疫荧光试验鉴定,结果显示BoIFN-γ在COS-7细胞中得到成功表达。将BoIFN-γ基因克隆到原核表达质粒pET-30a(+)、pGEX-6p-1后,分别转化重组表达菌BL21(DE3)、BL21后,通过对表达条件的优化,SDS-P 相似文献
998.
Liying Wang Chao Liu Bo Yang Haotian Zhang Jian Jiao Ruidan Zhang Shujun Liu Sai Xiao Yinghong Chen Bo Liu Yanjie Ma Xuefeng Duan Yueshuai Guo Mengmeng Guo Bingbing Wu Xiangdong Wang Xingxu Huang Haitao Yang Yaoting Gui Min Fang Luo Zhang Shuguang Duo Xuejiang Guo Wei Li 《The Journal of cell biology》2022,221(7)
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the causal pathogen of the ongoing global pandemic of coronavirus disease 2019 (COVID-19). Loss of smell and taste are symptoms of COVID-19, and may be related to cilia dysfunction. Here, we found that the SARS-CoV-2 ORF10 increases the overall E3 ligase activity of the CUL2ZYG11B complex by interacting with ZYG11B. Enhanced CUL2ZYG11B activity by ORF10 causes increased ubiquitination and subsequent proteasome-mediated degradation of an intraflagellar transport (IFT) complex B protein, IFT46, thereby impairing both cilia biogenesis and maintenance. Further, we show that exposure of the respiratory tract of hACE2 mice to SARS-CoV-2 or SARS-CoV-2 ORF10 alone results in cilia-dysfunction-related phenotypes, and the ORF10 expression in primary human nasal epithelial cells (HNECs) also caused a rapid loss of the ciliary layer. Our study demonstrates how SARS-CoV-2 ORF10 hijacks CUL2ZYG11B to eliminate IFT46 and leads to cilia dysfunction, thereby offering a powerful etiopathological explanation for how SARS-CoV-2 causes multiple cilia-dysfunction-related symptoms specific to COVID-19. 相似文献
999.
二元酸发酵过程中流加H2O2对细胞色素P450酶及产物生成的影响 总被引:2,自引:0,他引:2
在二元酸发酵过程中流加H2O2对热带假丝酵母发酵生产二元酸有明显的促进作用,2mmol/L的H2O2对产酸的促进作用最为明显,比对照提高了26%。对细胞色素P450酶的分析表明,流加H2O2对细胞色素P450酶的活性有明显的促进作用,并且细胞色素P450酶的活性跟产酸成正相关。此外,还进一步分析了流加H2O2对产酸的促进机理。 相似文献
1000.
角倍由角倍蚜Schlechtendaliachinensis(Bell)寄生在盐肤木RhuschinensisMill和滨盐肤木R.chinensisvar.raxburghii(DC)Rehd.叶上致瘿而形成,约占五倍子总产量的80%。藓圃上越冬若蚜和盐肤木林中角倍的分布均属聚集分布。影响越冬若蚜和角倍聚集度的主要生态因子分别为藓长势、湿度、光照和树与藓的距离、风向、风速。于母和雏倍分布在盐肤木和滨肤木的第5~11片叶上,其中7~9片叶上干母数和雏倍数超过50%。干母数与雏倍数存在着显著的线性关系。盐肤木上:y1=3.3394+0.7662x1,r1=0.9994**滨盐肤木上:y2=3.6707+0.7431x2,r2=0.9894** 相似文献