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Background and purpose: Circular RNA (CircRNA) is a type of non-coding RNA with a closed circular structure, which has important potential in gene expression regulation. CircRNA is closely related to the occurrence and development of tumor. This study aimed to explore the influence of hsa_circ_0001573 on the biological behavior of breast cancer cells and its mechanism. Methods: Breast cancer tissues and paracancerous tissues of 4 patients surgically removed at the First Affiliated Hospital of Chongqing Medical University from January 2020 to January 2021 were collected, sequenced and analyzed by RNA microarray analysis. Real-time fluorescence quantitative polymerase chain reaction (RTFQ-PCR) was used to detect the relative expression of hsa_circ_0001573 in breast cancer tissues and paracancerous tissues of 40 cases, as well as normal human breast cancer epithelial cell MCF-10A and breast cancer cells (MCF-7 and SK-BR-3), and the location and expression were further examined by fluorescence in situ hybridization (FISH) assay. The interference vector was transfected into breast cancer cells. Cell counting kit-8 (CCK-8), EdU, wound healing, clonal formation, Hoechst 33342, TUNEL, flow cytometry and transwell assays were adopted to determine cell migration, invasion, proliferation and apoptosis. Western blot was employed to measure the expressions of CCND1, CCND2 and CDK4. The effect of hsa_circ_0001573 on the growth of xenograft tumors was observed in nude mice. RNA pulldown assay was performed to identify hsa_circ_0001573-associated proteins. Subcellular localization of hsa_circ_0001573 and GNB4 was clarified by FISH and immunofluorescence (FISH-IF), to explore potential molecular mechanisms. Results: The expression level of hsa_circ_0001573 was high in breast cancer (P

Objective To explore the effects of the interaction between circular RNA hsa_circ_0000231 and HnRNPK on the proliferation, migration and apoptosis in breast cancer. Methods Microarray analysis was used to investigate the expression profile of circRNAs in 4 pairs of breast cancer tissues and corresponding adjacent normal tissues. A total of 35 breast cancer tissue specimens were collected from the patients admitted in the First Affiliated Hospital of Chongqing Medical University from September 2019 to January 2021. qRT-PCR was carried out to detect the relative expression of hsa_circ_0000231, and fluorescence in situ hybridization (FISH) assay was performed to observe its location and expression in the cells. Breast cancer MCF-7 and SK-BR-3 cells were transfected with the interference vector of hsa_circ_0000231 respectively. Then cell wound healing assay, CCK-8 assay, EdU cell proliferation assay, clone formation experiment, hoechst33342 staining, TUNEL, flow cytometry and Transwell assay were adopted to determine cell migration, invasion, proliferation and apoptosis, and Western blotting was employed to measure the expression of CCND2, CCND1 and CDK4 after the knockdown. The effect of hsa_circ_0000231 on the growth of transplanted tumors was observed in nude mice. RNA pulldown assay was performed to identify hsa_circ_0000231-associated proteins, and FISH-immunofluorescence (IF) assay were employed to clarify the subcellular localization of hsa_circ_0000231 and HnRNPK. qRT-PCR and Western blotting were conducted to detect the expression of c-Myc. Results Circular RNA hsa_circ_ 0000231 was highly expressed in breast cancer tissues (P < 0.001) and breast cancer cells (P < 0.01). Down-regulation of hsa_ circ_ 0000231 inhibited the proliferation, migration and invasion of breast cancer cells, induced cell apoptosis, led to cell cycle arrest in G1 phase, and obviously decreased the expression of CCND2, CCND1 and CDK4. The results of in vivo experiments showed that knockdown of hsa_circ_0000231 inhibited the growth of tumor xenograft. HnRNPK was co-localized in the nucleus with hsa_circ_0000231, and interacted with hsa_circ_0000231 to promote c-Myc expression. Conclusion Knockdown of hsa_ circ_ 0000231 could suppress the proliferation, migration and invasion of breast cancer cells, induce cell apoptosis and cell cycle arrest, and inhibit tumor growth in vivo. The interaction of hsa_circ_0000231 with HnRNPK enhances the expression of c-Myc, and thus promotes the occurrence and development of breast cancer.

Objective To investigate the expression of circular RNA circACTN4 (also called hsa_circ_0050900) in breast cancer (BC) and its effect on the proliferation, invasion and metastasis of BC cells. Methods The circRNA expression profiles of 4 pairs of BC tissues and adjacent tissues were analyzed by circRNA chip analysis, and the relative expression level of circACTN4 was detected by qRT-PCR. After BC cell lines MCF-7/MDA-MB-231 were transfected with circACTN4 overexpression plasmid and control plasmid, respectively, the effects of circACTN4 on cell proliferation, migration and invasion were tested by Cell Counting Kit-8 (CCK-8), EdU assay, colony formation, scratching assay, and Transwell migration and invasion assay. Western blotting was executed to determine the protein expression of CCND1, CCND2 and CDK4. The effects of circACTN4 on the growth and metastasis of transplanted tumors were also observed in nude mice. Results The expression of circACTN4 was significantly higher in BC tissues and cells than in the paired adjacent tissues and normal breast epithelial cells (P < 0.01). Up-regulation of circACTN4 enhanced the proliferation, migration and invasion of BC cells (P < 0.05), and facilitated the expression of CCND1, CCND2 and CDK4 (P < 0.01). The results of in vivo experiments also showed that up-regulation of circACTN4 promoted the growth and metastasis of transplanted tumors, with the tumor microvascular density and the number of lung metastatic nodules significantly increased in the circACTN4 group, as compared with the control group (P < 0.05). Conclusion circACTN4 is highly expressed in BC tissues and cells. It can promote the proliferation, migration and invasion of BC cells, and facilitate the growth and metastasis of transplanted tumors in vivo.

This paper introduces the principle of Hidden Markov Model, which is used to describe the Markov process with unknown parameters, is a probability model to describe the statistical properties of the random process. On this basis, designed a solitary word detection experiment based on HMM model, by optimizing the experimental model, Using Baum-Welch algorithm for training the problem of solving the HMM model, HMM model to estimate the parameters of the λ value is found, in this view of mathematics equivalent to other linear prediction coefficient. This experiment in reducing unnecessary HMM training at the same time, reduced the algorithm complexity. In order to test the effectiveness of the Baum-Welch algorithm. The simulation of experimental data, the results show that the algorithm is effective. [ABSTRACT FROM AUTHOR]

This paper firstly analyzes the influences of low load condition on natural gas treatment unit from two aspects: the low load condition can lead to surging, as well as yield decline, which directly affects the economic benefits. Secondly, aiming at the harm of units at low load condition, according to the experience formula of expansion refrigeration and throttling expansion, the methods, such as improving the processing capacity, the expansion ratio of expansion machine, and the throttle effect, and increasing the auxiliary refrigerating capacity, etc, are used to reduce top temperature of methane tower, so as to improve the unit yield. These measures have certain reference significance to the operation of similar natural gas treatment plant. [ABSTRACT FROM AUTHOR]

We wished to explore the ability of the meq-deleted Marek's disease virus (MDV) vaccine strain SC9-1 to acquire the meq gene from the MDV wild strain Md5 by recombination. Chicken embryo fibroblast cells (CEFs) were co-infected with the SC9-1 vaccine virus and Md5 virus, passaged to third generation, and viral DNA was extracted from a single plaque in the cell culture. Specific pathogen-free chickens pre-immunized with the SC9-1 vaccine virus were infected with the Md5 virus. Viruses were isolated from chickens-at different time points. Then, viral DNA was extracted from a single plaque and amplification by polymerase chain reaction done to identify isolated viruses. The flip recombina-se sites (FRT) residue region was cloned and sequenced. Results showed that the isolated viruses in cultured CEFs or in chickens were the SC9-1 or Md5 virus, and recombinant viruses were not detected. Sequence analyses revealed that the homology of the FRT residue sequence between the isolated virus and parent virus was 100%. Therefore, there is little chance that SC9-1 can acquire the meq gene from Md5 by natural recombination. Also, the meq-gene knockout region had good genetic stability during serial passages in vivo and in vitro.

We used a meq-deleted attenuated MDV-I strain GX0101Δmeq as a vector to construct a recombinant virus expressing the exogenous gene NDV-F. The ORF of exogenous gene NDV-F was inserted into the eukaryotic expression vector pcDNA3.1(-). Then, the expression cassette of NDV-F which contains the CMV promoter was amplified. Simultaneously, we amplified the selected gene Kan+ expression cassette and inserted them into the PMD18-T vector. Tandem expression cassettes were amplified using primers containing the 50-bp homologous arm of MDV-US2. The PCR product was electroporated into EL250 host bacteria containing GX0101Δmeq. Then, the Kan+ expression cassette was deleted from the recombinant virus genome using 1% arabinose. The plasmid of the positive clone which the Kan+ expression cassette was deleted was extracted and transfected into CEFs to rescue the recombinant virus. The recombinant virus was injected into chickens to observe its growth and replication. The recombinant virus rMDV-F containing the exogenous gene NDV-F was rescued successfully. The recombinant virus could duplicate and express well in CEFs, and grow and replicate well in chickens. Using GX0101Δmeq as a vector, combined with a recombinant system of Red E/T and FLP/FRT, we constructed a recombinant virus that expressed the exogenous gene NDV-F. This study could lay the foundation for further study of recombinant viruses.