Modeling of Poly(3-hydroxybutyrate) Production by High Cell Density Fed-batch Culture of Ralstonia eutropha

Shang, Longan,Fan, Dai Di,Kim, Moon-Il,Choi, Jin-dal-rae,Chang, Ho-Nam Korean Society for Biotechnology and Bioengineerin 2007 Biotechnology and Bioprocess Engineering Vol.12 No.4

High cell density culturing has been conducted for the production of poly(3-hydroxybutyrate) fed-batch cultures of Ralstonia eutropha with phosphate limitation. It was found that a high glucose concentration inhibited the synthesis of P(3HB) in the high cell density culture of R. eutropha. Although a low glucose concentration can trigger the synthesis of P(3HB) in a manner similar to that of phosphate limitation, it also limited both the P(3HB) synthesis and the cell growth, and led to a low P(3HB) productivity because glucose is the sole carbon source in this reaction. An unstructured model was proposed for predicting the cell growth and P(3HB) synthesis in high cell density cultures of R. eutropha, where the phosphate concentration played a key role in the accumulation of P(3HB) and in cell growth. Good agreements were found between the experimental data and model predictions. The results of simulation showed that the final P(3HB) concentration would decrease more than 25% when the glucose was concentration increased to 40 g/L, and indicated that the optimal glucose concentration for P(3HB) production by high cell density cultures of R. eutropha was around 9g/L.

BLOW-UP TIME AND BLOW-UP RATE FOR PSEUDO-PARABOLIC EQUATIONS WITH WEIGHTED SOURCE

Di, Huafei,Shang, Yadong Korean Mathematical Society 2020 대한수학회논문집 Vol.35 No.4

In this paper, we are concerned with the blow-up phenomena for a class of pseudo-parabolic equations with weighted source u_t - △u - △u_t = a(x)f(u) subject to Dirichlet (or Neumann) boundary conditions in any smooth bounded domain Ω ⊂ ℝⁿ (n ≥ 1). Firstly, we obtain the upper and lower bounds for blow-up time of solutions to these problems. Moreover, we also give the estimates of blow-up rate of solutions under some suitable conditions. Finally, three models are presented to illustrate our main results. In some special cases, we can even get some exact values of blow-up time and blow-up rate.

Blow-up time and blow-up rate for pseudo-parabolic equations with weighted source

Huafei Di,Yadong Shang 대한수학회 2020 대한수학회논문집 Vol.35 No.4

In this paper, we are concerned with the blow-up phenomena for a class of pseudo-parabolic equations with weighted source $u_{t}-\triangle u-\triangle u_{t}=a(x)f(u)$ subject to Dirichlet (or Neumann) boundary conditions in any smooth bounded domain $\Omega\subset \mathbb{R}^{n}$ $(n\geq1)$. Firstly, we obtain the upper and lower bounds for blow-up time of solutions to these problems. Moreover, we also give the estimates of blow-up rate of solutions under some suitable conditions. Finally, three models are presented to illustrate our main results. In some special cases, we can even get some exact values of blow-up time and blow-up rate.

Modeling of Poly(3-hydroxybutyrate)Production by High Cell Density Fed-batchCulture of Ralstonia eutropha

장호남,김문일,Longan Shang,Dai Di Fan,Jin-dal-rae Choi 한국생물공학회 2007 Biotechnology and Bioprocess Engineering Vol.12 No.4

High cell density culturing has been conducted for the production of poly(3-hydroxybutyrate) fed-batch cultures of Ralstonia eutropha with phosphate limitation. It was found that a high glucose concentration inhibited the synthesis of P(3HB) in the high cell density culture of R. eutropha. Although a low glucose concentration can trigger the synthesis of P(3HB) in a manner similar to that of phosphate limitation, it also limited both the P(3HB) synthesis and the cell growth, and led to a low P(3HB) productivity because glucose is the sole carbon source in this reaction. An unstructured model was proposed for predicting the cell growth and P(3HB) synthesis in high cell density cultures of R. eutropha, where the phosphate concentration played a key role in the accumulation of P(3HB) and in cell growth. Good agreements were found between the experimental data and model predictions. The results of simulation showed that the final P(3HB) concentration would decrease more than 25% when the glucose was concentration increased to 40 g/L, and indicated that the optimal glucose concentration for P(3HB) production by high cell density cultures of R. eutropha was around 9 g/L.

Value of Postoperative Radiation Therapy for Regional Control after Dissection in Head and Neck Squamous Cell Carcinoma Cases

Li, Xiao-Ming,Di, Bin,Shang, Yao-Dong,Tao, Zhen-Feng,Cheng, Ji-Min,He, Zhan-Guo Asian Pacific Journal of Cancer Prevention 2013 Asian Pacific journal of cancer prevention Vol.14 No.7

Objective: We aimed to define clinicopathologic risk factors associated with regional recurrence (RR) and thus the effectiveness of postoperative radiotherapy (PORT) for neck control for head and neck squamous cell carcinomas (HNSCCs) with differing cervical lymph node status. Methods: A retrospective study was performed in 196 HNSCC patients with pathologically positive neck node (N+) to evaluate the high-risk factors for RR and to define the role of PORT in control after neck dissection and postoperative radiotherapy (PORT). Results: Overall, the RR rate after neck dissection and PORT was 29%. Extracapsular spread (ECS) was confirmed to be the only independent risk factor for RR. There were no significant risk factors associated with RR in the ECS- group. The 5-year disease-specific survival rate was 45%, which descended to 10% with the emergence of RR. Conclusions: ECS remains a determined risk factor for RR after neck dissection and PORT in patients with N+. PORT alone is not adequate for preventing RR in the neck with ECS after neck dissection. More intensive postoperative adjuvant therapies, especially combined chemotherapy and radiotherapy, are needed to prevent regional failure in HNSCC patients with ECS.

SIRT5-related desuccinylation modification of AIFM1 protects against compression-induced intervertebral disc degeneration by regulating mitochondrial homeostasis

Mao Jianxin,Wang Di,Wang Dong,Wu Qi,Shang Qiliang,Gao Chu,Wang Huanbo,Wang Han,Du Mu,Peng Pandi,Jia Haoruo,Xu Xiaolong,Wang Jie,Yang Liu,Luo Zhuojing 생화학분자생물학회 2023 Experimental and molecular medicine Vol.55 No.-

Mitochondrial dysfunction plays a major role in the development of intervertebral disc degeneration (IDD). Sirtuin 5 (SIRT5) participates in the maintenance of mitochondrial homeostasis through its desuccinylase activity. However, it is still unclear whether succinylation or SIRT5 is involved in the impairment of mitochondria and development of IDD induced by excessive mechanical stress. Our 4D label-free quantitative proteomic results showed decreased expression of the desuccinylase SIRT5 in rat nucleus pulposus (NP) tissues under mechanical loading. Overexpression of Sirt5 effectively alleviated, whereas knockdown of Sirt5 aggravated, the apoptosis and dysfunction of NP cells under mechanical stress, consistent with the more severe IDD phenotype of Sirt5 KO mice than wild-type mice that underwent lumbar spine instability (LSI) surgery. Moreover, immunoprecipitation-coupled mass spectrometry (IP-MS) results suggested that AIFM1 was a downstream target of SIRT5, which was verified by a Co-IP assay. We further demonstrated that reduced SIRT5 expression resulted in the increased succinylation of AIFM1, which in turn abolished the interaction between AIFM1 and CHCHD4 and thus led to the reduced electron transfer chain (ETC) complex subunits in NP cells. Reduced ETC complex subunits resulted in mitochondrial dysfunction and the subsequent occurrence of IDD under mechanical stress. Finally, we validated the efficacy of treatments targeting disrupted mitochondrial protein importation by upregulating SIRT5 expression or methylene blue (MB) administration in the compression-induced rat IDD model. In conclusion, our study provides new insights into the occurrence and development of IDD and offers promising therapeutic approaches for IDD.

Prognostic Significance of Tumor Mutation Burden among Patients with Non-small Cell Lung Cancer Who Received Platinum-based Adjuvant Chemotherapy: An Exploratory Study

Wei-Xi Shen,Guang-Hua Li,Yu-Jia Li,Peng-Fei Zhang,Jia-Xing Yu,Di Shang,Qiu-Shi Wang 대한암예방학회 2023 Journal of cancer prevention Vol.28 No.4

This study aimed to investigate the prognostic significance of tumor mutation burden (TMB) among patients with non-small cell lung cancer (NSCLC) who received platinum-based adjuvant chemotherapy. Tumor tissue specimens after surgical resection were collected for DNA extraction. Somatic mutation detection and TMB analysis were conducted using next-generation sequencing (NGS). Recurrence status of the patients was assessed in the hospital during the adjuvant chemotherapy period, and long-term survival data of patients were obtained by telephone follow-up. Univariate analysis between TMB status and prognosis was carried out by survival analysis. A retrospective review of 78 patients with non-squamous NSCLC who received platinum-based adjuvant chemotherapy showed a median disease-free survival of 3.6 years and median overall survival (OS) of 5.3 years. NGS analysis exhibited that the most common mutated somatic genes among the 78 patients were tumor suppressor protein p53 (TP53), epidermal growth factor receptor, low-density lipoprotein receptor related protein 1B, DNA methyltransferase 3 alpha and FAT atypical cadherin 3, and their prevalence was 56.4%, 48.7%, 37.2%, 30.7%, and 25.6%, respectively. TMB status was divided into TMB-L (≤ 4.5/Mb) and TMB-H (> 4.5/Mb) based on the median TMB threshold. Relevance of TMB to prognosis suggested that the median OS of patients with TMB-L was significantly longer than that of patients with TMB-H (NR vs. 4.6, P = 0.014). Higher TMB status conferred a worse implication on OS among patients with non-squamous NSCLC who received platinum-based adjuvant chemotherapy.