Pyruvate phosphate dikinase (PPDK; EC 2.7.9.1) is found in certain microorganisms and plants, and catalyzes the conversion of AMP, PPi and phosphoenolpyruvate (PEP) to ATP, Pi and pyruvate. Using the genomic DNA of Microbispora rosea subsp. aerata as the template, a DNA fragment encoding the gene PPDK was amplified by PCR and inserted into the expression vector pET28a(+), yielding pET28a (+)-PPDK. The E. coli BL21 (DE3) was transformed with the pET28a (+)-PPDK. After inducing with IPTG, the E. coli BL21 (DE3) [pET28a (+)-PPDK] expressed recombinant PPDK fused to an N-terminal sequence of 6-His Tag. The molecular weight of PPDK was estimated to be 101 kD by SDS-PAGE. The PPDK was purified by His * Bind Resin affinity chromatography and ultrafiltration using 10 kD cut-off membrane. The successful application of PPDK in pyrosequencing was also demonstrated.
Actinomyces ; enzymology ; Escherichia coli ; genetics ; metabolism ; Pyruvate, Orthophosphate Dikinase ; biosynthesis ; genetics ; Recombinant Fusion Proteins ; biosynthesis ; genetics ; Recombination, Genetic ; Sequence Analysis

We expressed recombinant single-stranded DNA-binding protein (r-SSBP) from Escherichia coli with the molecular weight of 24-kDa by using genetic engineering strategy, and demonstrated the single-stranded DNA (ssDNA)-binding activity of r-SSBP by electrophoretic mobility shift assay (EMSA). To further characterize r-SSBP, we studied the effects of r-SSBP on melting temperature (T(m)) of DNA. The results showed that r-SSBP could bind to ssDNA, and lower the T(m) of DNA, especially for single-base mismatched DNA. Therefore, r-SSBP significantly increased the T(m) difference between single-base mismatched DNA and perfect matched DNA. These results are very beneficial for single-nucleotide polymorphism detection. Moreover, we applied r-SSBP in high sensitive pyrosequencing system developed by our group. The results suggest that the r-SSBP decreased non-specific signals, corrected the proportion of signal peak height and improved the performance of pyrosequencing.
DNA-Binding Proteins ; biosynthesis ; genetics ; Diphosphates ; metabolism ; Escherichia coli ; genetics ; metabolism ; Genetic Vectors ; Recombinant Proteins ; biosynthesis ; genetics ; Sequence Analysis, DNA ; methods

Objective:To evaluate the effects of exogenous biliverdin (BV) on the expression of Litaf in PC12 cells subjected to oxygen-glucose deprivation and restoration (OGD/R).Methods:PC12 cells were seeded in a 96-well cell culture plate at a density of 1×10 4 cells/well for 3 days and were divided into 3 groups ( n=18 each) by a random number table method: control group (group C), OGD/R group, and biliverdin group (BV group). Group C was incubated in a 37 ℃ incubator (95% air+ 5%CO 2) for 6 h. To establish the OGD/R model, cells were incubated with sugar-free medium in a 37 ℃ incubator (95% air+ 5%CO 2) for 2 h, and the medium was then replaced with normal medium and cells were continuously incubated in a 37 ℃ incubator (95% N 2+ 5% CO 2). In BV group, 2 μg/ml biliverdin was added immediately after oxygen-glucose restoration.Cells in 6 wells in each group were selected at 6 h of restoration for determination of the expression of Litaf protein and mRNA (by real-time polymerase chain reaction) and tumor necrosis factor-alpha (TNF-α) concentration (by enzyme-linked immunosorbent assay). Results:Compared with group C, the expression of Litaf protein and mRNA was significantly up-regulated, and TNF-α concentration in supernatant was increased in group OGD/R ( P<0.05). Compared with group OGD/R, the expression of Litaf protein and mRNA was significantly down-regulated, and TNF-α concentration in supernatant was decreased in group BV ( P<0.05). Conclusion:The mechanism by which exogenous biliverdin reduces OGD/R damage to PC12 cells is related to inhibiting up-regulated expression of Litaf and alleviating the inflammatory responses.

OBJECTIVES: The interaction between elderly people with disabilities and their caregivers and the improvement of caregiver burden is important for elderly people with disabilities and their caregivers. This study aims to explore the multiple mediating roles of caregiver's caring ability and resilience in depression in the elderly people with disabilities on caregiver burden. METHODS: A total of 246 elderly people with disabilities at home and their family caregivers from 5 regions were investigated by questionnaires, including the General Information Questionnaire, the Patient Health Questionnaire, the Family Caregiver Task Inventory, the Resilience Scale, and the Caregiver Burden Interview. A multiple mediation model was constructed and tested. RESULTS: Univariate analysis showed that the caregiver burden of disabled elderly men is higher than that of women; the lower the level of self-care of disabled elderly individuals, the greater the burden on their caregivers (both P<0.05). Correlation analysis showed that depression of the disabled elderly people was positively correlated with the caregiver burden (P<0.01). Caregiver's caring ability was positively correlated with caregiver's resilience (P<0.01), and both were negatively correlated with caregiver burden (both P<0.01). The multiple mediating effects of caregiver caring capacity and resilience between depression of the disabled elderly people and caregiver burden were significant, with the mediating effects of caregiver caring capacity and resilience accounting for 68.9% and 26.2% of the total effect, respectively. CONCLUSIONS Depression in the elderly people with disabilities can indirectly affect caregiver burden through the caregiver's caring ability and resilience. Families of older people with disabilities need to focus on both the elderly and their caregivers. It is possible to reduce the caregiver burden and improve the physical and mental health of the dyads by empowering the caregiver's caring ability and resilience.
Male ; Humans ; Female ; Aged ; Caregiver Burden ; Disabled Persons ; Caregivers ; Surveys and Questionnaires ; Mental Health