OBJECTIVE: To establish a quantitative fluorescent detection method using DAPI for detecting inorganic polyphosphate (polyP) in enterohemorrhagic Escherichia coli (EHEC) O157:H7. METHODS: The DNA of wild-type strain of EHEC O157:H7 was extracted and purified. DAPI was combined with the extracted DNA and polyP45 standards for measurement of the emission spectra at 360 nm and 415 nm fluorescence spectrophotometry. The fluorescence of DAPI-DNA and DAPI-polyP complexes was detected by fluorescence confocal microscopy to verify the feasibility of DAPI for detecting polyP. To determine the optimal pretreatment protocol for improving the cell membrane permeability, the effects of 6 pretreatments of the cells (namely snap-freezing in liquid nitrogen, freezing at -80 ℃, and freezing at -20 ℃, all followed by thawing at room temperature; heating at 60 ℃ for 10 min; treatment with Triton x-100; and placement at room temperature) were tested on the survival of EHEC O157:H7. The fluorescence values of the treated bacteria were then measured after DAPI staining. A standard calibration curve of polyP standard was established for calculation of the content of polyP in the live cells of wildtype EHEC strain and two mutant strains. RESULTS: At the excitation wavelength of 360 nm, the maximum emission wavelength of DAPI-DNA was 460 nm, and the maximum emission wavelength of DAPI-polyP was 550 nm at the excitation wavelength of 415 nm. The results of confocal microscopy showed that 405 nm excitation elicited blue fluorescence from DAPIDNA complex with the emission wavelength of 425-475 nm; excitation at 488 nm elicited green fluorescence from the DAPIpolyP complex with the emission wavelength of 500-560 nm of. Snap-freezing of cells at -80 ℃ followed by thawing at room temperature was the optimal pretreatment to promote DAPI penetration into the live cells. The standard calibration curve was =1849+127.5 (R=0.991) was used for determining polyP content in the EHEC strains. The experimental results showed that wild-type strain had significantly higher polyP content than the mutant strains with deletion. CONCLUSIONS We established a convenient quantitative method for direct and reliable detection polyP content to facilitate further study of polyP and its catalytic enzymes in EHEC O157:H7.
Escherichia coli O157 ; Escherichia coli Proteins ; Polyphosphates

Adenosine triphosphate (ATP)-sensitive potassium (KATP) channels in pancreatic beta-cells play a crucial role in insulin secretion and glucose homeostasis. These channels are composed of two subunits: a pore-forming subunit (Kir6.2) and a regulatory subunit (sulphonylurea receptor-1). Recent studies identified large number of gain of function mutations in the regulatory subunit of the channel which cause neonatal diabetes. Majority of mutations cause neonatal diabetes alone, however some lead to a severe form of neonatal diabetes with associated neurological complications. This review focuses on the functional effects of these mutations as well as the implications for treatment.
Adenosine Triphosphate ; Glucose ; Homeostasis ; Insulin ; KATP Channels ; Polyphosphates ; Potassium

OBJECTIVETo develop a best chitosan film for using as a drug sustained-release system through the evaluation of the sustained-release property, degradation property, and cytotoxicity to osteoblast.

METHODSOrthogonal experiments were designed to determine the best combination of chitosan film preparations. Drug release rate was determined with Coomassie brilliant blue G250. In a separate study, chitosan films were placed into the test tubes with buffer solution and 10(7) U/L lysozyme. The degradation rate was calculated. Osteoblasts derived from fetal rat calvarial were cultured on chitosan films. Cell proliferation was tested by methyl thiazolyl tetrazolium (MTT) assay. The relative growth rate was calculated and the cytotoxicity was graded.

RESULTSThe best processing condition was 1% acetic acid, chitosan concentration of 2 mg/mL, 6% sodium tripolyphosphate (STPP) concentration, and cross-linking time of one hour. The resulting chitosan film released 33.13% of bovine serum albumin (BSA) within 8 d, 36.73% of BSA within four weeks and the cytotoxicity grade was 0 or 1.

CONCLUSIONThis chitosan film possesses good sustained release property, and a good degradation rate.

Adenosine triphosphate (ATP) regeneration systems are essential for efficient biocatalytic phosphoryl transfer reactions. Polyphosphate kinase (PPK) is a versatile enzyme that can transfer phosphate groups among adenosine monophosphate (AMP), adenosine diphosphate (ADP), ATP, and polyphosphate (Poly P). Utilization of PPK is an attractive solution to address the problem of ATP regeneration due to its ability to use a variety of inexpensive and stable Poly P salts as phosphate group donors. This review comprehensively summarizes the structural characteristics and catalytic mechanisms of different types of PPKs, as well as the variations in enzyme activity, catalytic efficiency, stability, and coenzyme preference observed in PPKs from different sources. Moreover, recent advances in PPK-mediated ATP regeneration systems and protein engineering of wild-type PPK are summarized.
Adenosine Triphosphate/metabolism* ; Adenosine Monophosphate ; Polyphosphates/metabolism* ; Catalysis ; Regeneration

PURPOSE: Breast cancer is heterogeneous disease and the response to chemotherapeutic agents is also heterogeneous from patient to patient. Chemotherapy response assay is in vitro test that is performed to evaluate the degree of tumor growth inhibition by chemotherapy drugs. In this study, we performed the chemotherapy response assay using adenosine triphosphate (ATP-CRA) in breast cancer patients and assessed the clinical availability. METHODS: Sixty five breast cancer patients were enrolled in this study. Cancer cells were evenly divided and treated with commonly used chemotherapeutic drugs in breast cancer (doxorubicin, epirubicin, 5-fluorouracil, paclitaxel, docetaxel, vinorelbine, and gemcitabine). To verify in vitro ATP-CRA indirectly, we analyzed the correlation between cell death rate (CDR) of doxorubicin and epirubicin, and between doxorubicin and paclitaxel. We also analyzed the mean CDR of doxorubicin, epirubicin and paclitaxel by HER2 status. RESULTS: We could successfully perform the ATP-CRA in 60 patients (95.2%). In all cases, we can get the results within 7 days. The range of CDR was very wide, from 0 to more than 50%, except gemcitabine. Epirubicin showed the highest mean CDR (39.9%) and doxorubicin, paclitaxel in order. According to the chemosensitivity index, paclitaxel is the most frequently first-ranked and doxorubicin, epirubicin in order. Correlation coefficient between the cell death rate of doxorubicin and epirubicin is 0.4210 and 0.1299 between paclitaxel and doxorubicin. In HER2 positive group, mean CDR of paclitaxel, epirubicin and doxorubicin was higher than in HER2 negative group, even though epirubicin and doxorubicin were not statistically significant (p=0.018, p=0.114, p=0.311, respectively). CONCLUSION: ATP-CRA showed heterogeneous results in individual patients. ATP-CRA was successful and can be performed within short time period. According to our in vitro study, it showed similar results with in vivo study but for the clinical use, the prospective randomized controlled trial should be preceded.
Adenosine Triphosphate ; Breast ; Breast Neoplasms ; Cell Death ; Deoxycytidine ; Doxorubicin ; Epirubicin ; Fluorouracil ; Humans ; Paclitaxel ; Polyphosphates ; Taxoids ; Vinblastine

STUDY DESIGN: Posterior and posterolateral fusions were performed in rabbit lumbar spines. OBJECTIVES: To investigate the osteoinductive effect of polyphosphates. SUMMARY AND LITERATURE REVIEW: Inorganic polyphosphates are known to be rich in osteoblasts and involved in the mineralization process in bone metabolism. However, no study has been undertaken to investigate the osteoinductive effect of polyphosphates. MATERIALS AND METHODS: Forty adult New Zealand white rabbits underwent monolevel lumbar fusions, and were divided into two groups according to the fusion beds: twenty each between the laminae (posterior fusion group, PF group) and between the transverse processes (posterolateral fusion group, PLF group). In ten of twenty rabbits in the PF group, 0.8gm of autogenous iliac bone was grafted onto the right sides of the laminae, which were used as a control group (C1), with 0.4gm autogenous bone immersed in polyphosphate solution in the left sides as an experimental group (E1). In the other ten, 0.8gm of autogenous bone was grafted onto the right sides (C2) and 0.8gm of tricalcium phosphate porous blocks containing polyphosphate in the left sides (E2). The other twenty rabbits of the PLF group were similarly divided into C1, E1, C2 and E2 groups by grafting the same amount of materials between the transverse processes. The animals were sacrificed at the 16th postoperative week and the fusions evaluated grossly, radiologically and histologically. Statistical differences between the groups (C1 vs. E1, C2 vs. E2 and E1 vs. E2) in each of the PF and PLF groups were compared by chi-square tests. RESULTS: The fusions were finally determined by the gross finding using manual palpation. In the PF group, bony fusions were obtained in 90, 80, 90 and 70% of the C1, E1, C2 and E2 groups, respectively. In the PLF group, these were 80, 70, 60 and 0% of the C1, E1, C2 and E2 groups, respectively. Statistical analysis revealed differences only between C2 and E2 (p=0.005), and between E1 and E2 (p=0.002) of the PLF group. Histologically, beta-tricalcium phosphate particles containing polyphosphate were transformed into the osteoid in some areas of the PLF-E2 group, although only fibrous unions were obtained grossly. CONCLUSIONS: It is suggested that the polyphosphate may have an osteoinductive effect, even though the osteoinductive potency was very week in this fusion model of the rabbit lumbar spine. Therefore, further explorations, such as the threshold and optimal concentrations of polyphosphate in vivo and the best carrier material of polyphosphate, should be performed to obtain the optimal conditions for fusion.
Adult ; Animals ; Bone Regeneration ; Humans ; Metabolism ; Osteoblasts ; Palpation ; Polyphosphates ; Rabbits ; Spine* ; Transplants

With glucose as substrate, sodium tripolyphosphate as the phosphorus acylating agent, and phosphorylase of Solanum tuberosum as the catalyst, glucose 1-phosphate was synthesized. Based on a three-level, three-variable Box-Behnken experimental design, response surface methodology was used to evaluate the effects of temperature, molar ratio of glucose to sodium tripolyphosphate and time on the production. The structure of the product was confirmed by 1H NMR spectra. The results show that the optimum conditions were as follows: temperature 35 degrees C, molar ratio of glucose to sodium tripolyphosphate 1.35:1 and time 19 h.
Catalysis ; Glucose ; metabolism ; Glucosephosphates ; biosynthesis ; Phosphorylases ; metabolism ; Polyphosphates ; chemistry ; Solanum tuberosum ; enzymology ; Surface Properties

Calcium polyphosphate (CPP) may be a promising bone substitute with controllably-degraded ability. In this investigation, the effects of sintering temperatures on its phase transformation and structure parameters, such as crystalline size distribution and micro-strain were investigated by X-ray diffraction (XRD). The phase composition was calculated with reference intensity ratio (RIR). The crystalline size distribution and micro-strain were calculated with Warren-Averbach Fourier transfer (W-A/FT) method. The results demonstrated that at the temperature of 585 degrees C-900 degrees C, the phase transformation of amorphous CPP into crystalline gamma-CPP and then into beta-CPP occurred,and the course of such transformation was accompanied with the significant change of the mean crystalline size (D) and the mean micro-strain (epsilon).
Biocompatible Materials ; Biodegradation, Environmental ; Bone Substitutes ; chemistry ; Calcium ; chemistry ; Humans ; Polyphosphates ; chemistry ; Stress, Mechanical

Polyphosphate kinase plays an important role in the catalytic synthesis of ATP in vitro. In order to find a polyphosphate kinase that can efficiently synthesize ATP using short-chain polyphosphate (polyP) as substrate, the polyphosphate kinase 2 (PPK2) from Sphingobacterium siyangensis was cloned and expressed in Escherichia coli BL21(DE3). As an enzyme for ATP regeneration, PPK2 was used in combination with l-amino acid ligase (YwfE) to produce l-alanyl-l-glutamine (Ala-Gln). The length of ppk2 of S. siyangensis is 810 bp, encoding 270 amino acids. The SDS-PAGE showed that PPK2 was expressed correctly and its molecular weight was 29.7 kDa as expected. The reaction conditions of PPK2 were optimized. PPK2 could maintain good activity in the range of 22-42 ℃ and pH 7-10. The highest enzyme activity was observed at 37 ℃, pH 7, 30 mmol/L magnesium ion (Mg²⁺), 5 mmol/L ADP and 10 mmol/L sodium hexametaphosphate, and the yield of ATP reached 60% of the theoretical value in 0.5 hours at this condition. When used in combination with YwfE to produce Ala-Gln, the PPK2 showed a good applicability as an ATP regeneration system, and the effect was similar to that of direct addition of ATP. The PPK2 from S. siyangensis shows good performance in a wide range of temperature and pH, synthesizes ATP with cheap and readily available short chain polyP as substrate. The PPK2 thus provides a new enzyme source for ATP dependent catalytic reaction system.
Sphingobacterium/metabolism* ; Phosphotransferases (Phosphate Group Acceptor)/metabolism* ; Amino Acids ; Adenosine Triphosphate ; Regeneration ; Polyphosphates/metabolism*

Breast cancer is the most common malignancy, and it is also the major cause of cancer-related deaths of women worldwide. Breast cancer treatment involves surgery, chemotherapy, radiation therapy, or combination therapy, and novel strategies are needed to boost the oncologic outcome. The non-metabolizable glucose analogue, 2-deoxy-D-glucose (2-DG) which inhibits glucose synthesis and adenosine triphosphate production, is one of the important discoveries involving the disturbances that can be caused to the process of the metabolism. The glucose analogue, 2-DG, is known as a tumor sensitizer to irradiation (IR) and chemotherapy, which help improve the treatment rates. It enhances the cytotoxicity via oxidative stress, which is more redundant in tumor cells than in normal ones. This article provides a brief summary on studies related to 2-DG chemo-/radio-sensitization effects by combination therapy of 2-DG/IR or 2-DG/doxorubicin.
Adenosine Triphosphate ; Breast ; Breast Neoplasms ; Cell Line, Tumor ; Combined Modality Therapy ; Deoxyglucose ; Female ; Glucose ; Humans ; Oxidative Stress ; Polyphosphates ; Radiation Tolerance