As an important material in pharmaceutical and chemical industry, β-alanine was mainly produced by chemical methods. L-aspartate-α-decarboxylase could catalyze the α-decarboxylation from L-aspartate to β-alanine. Determinations for specific activities of PanDs from Escherichia coli, Corynebacterium glutamicum and Bacillus subtilis were performed in this study (0.98 U/mg, 7.52 U/mg and 8.4 U/mg respectively). The optimal temperature and pH of PanDs from C. glutamicum and B. subtilis were 65 degrees C, pH 6.5 and 60 degrees C, pH 6.5 respectively. According to our research, PanD from B. subtilis could be more appropriate for industrial application because of the higher activity and thermostability when compared to PanDs from E. coli and C. glutamicum which had been the most studied. We also analyzed and discussed the special post-translation self-cleavage phenomenon and the mechanism based inactivation.
Bacillus subtilis ; enzymology ; Bacterial Proteins ; genetics ; metabolism ; Corynebacterium glutamicum ; enzymology ; Escherichia coli ; enzymology ; Glutamate Decarboxylase ; genetics ; metabolism ; Industrial Microbiology ; Temperature ; beta-Alanine

Objective To study the effects ofShenqi YizhiGranules (SQYZ) on learning and memory and content of Aβ1-42 of cerebral tissue in 5XFAD mice with Alzheimer’s disease; To discuss its mechanism on improving learning and memory ability of 5XFAD mice.Methods Four-month-old C57BL?6 wild type mice were randomly divided into NS control group and SQYZ control group, and the 5XFAD mice were randomly divided into model group, SQYZ group and huperzine-A (HupA) group, 15 mice in each group. Each group were given same volume for gavage for 60 d. After treatment, the learning and memory ability were evaluated by nesting test, passive avoidance and Morris water maze test. The senile plaques and content of Aβ1-42, ionized calcium binding adapter molecule 1 and glial fibrillary acidic protein in cerebral cortex and hippocampus were detected by immunohistochemical staining and immunofluorescence, respectively.Results Compared with NS control group, the score of nesting test in model group significantly decreased; the step-through latency in passive avoidance was shortened and the escape latentcy in Morris water maze test was prolonged; the quantity of senile plaques and content of Aβ1-42 increased in cerebral cortex and hippocampus; the activation of glial cells significantly increased. In the SQYZ group, the above-mentioned indexes reached or approached the level of wild type control mice. The difference between SQYZ group and model group was statistically significant (P<0.05,P<0.01).Conclusion SQYZ improved learning and memory ability in 5XFAD mice, which may be related to reduction of senile plaques, inhibition of over activation in glial cells and reduction of content of Aβ1-42 in cerebral cortex and hippocampus.

Objective To investigate the effect of Beraprost Sodium and atorvastatin in the treatment of TIA combined carotid plaques. Method 60 cases in our hospital with TIA and carotid artery plaques were randomly divided into observation group and control group, 30 cases in each group. The observation group was received beraprost natriuretic peptide and atorvastatin calcium therapy, the control group was treated with atorvastatin calcium. 12 months later,two groups were compared with carotid plaque area change and coagulation conditions. Results Carotid plaque area in observed group was significantly less than the control group (P<0.05). The differences of platelet agglutination test(PAgT), fibrinogen(Fg) , hypersensieive 3 C-reaction protein, total cholesterol(TC), high density lipoprotein cholesterol (HDL), low density lipoprotein cholesterol (LDL), TIA recurrence rate and incidence of ischemic stroke between two groups after treatment were statistically significant (P<0.05). Conclusion Beraprost Sodium and atorvastatin has a good effect in reducing carotid plaques area, adjusting blood fat and preventing TIA and ischemic stroke, It is worthy to clinical popularization and application.

Objective To investigate the relation of 11C-methionine (11C-MET) uptake with cell proliferation and angiogenesis in human brain gliomas .Methods For 30 cases of newly diagnosed glioma patients ,positron emission tomography (PET ) examina-tion with 11C-MET was performed ,and the maximal standardized uptake value (SUVmax) of 11C-MET was measured .Expression of Ki-67 and CD34 antigens was examined by immunohistochemistry method in the same glioma samples ,both Ki-67 labeling index (Ki-67 LI) and microvessel density (MVD) were measured .Results Both 11C-MET SUVmax and Ki-67 LI increased significantly with glioma pathological grade ascending (P=0 .000 ,P=0 .000) ,and which in malignant glioma tissues were significantly higher than those in benign glioma tissues as well (P=0 .000 ,P=0 .000);however ,there were not significant differences in MVD among different grades of gliomas (P=0 .831) as well as between high and low malignant gliomas (P=0 .370) .11 C-MET SUVmax was significantly positively correlated with Ki-67 LI (P= 0 .000) ,however ,there were not significant correlations between 11C-MET SUVmax and MVD (P=0 .154) as well as between Ki-67 LI and MVD (P=0 .842) .Conclusion 11C-MET uptake and cell prolif-eration activity can better reflect the pathological grades and malignant degrees of gliomas .

Objective To detect the expression of extracellular-regulated kinase (ERK) and phosphatedextracellular-regulated kinase (P-ERK) in the hippocampus after pentylenetetrazoloe-induced status epilepsy and the effects of nimodipine on it.Methods Male Sprague-Dawley adult rats (200-250 g) were randomly divided into normal control group(NC,n =35),status epilepsy group (SE,n =40),nimodipine group (NIM,n =40).The rats were injected first with 40 mg/kg pentylenetetrazoloe(PTZ),followed 10 minutes later by 20 mg/kg PTZ,and subsequently,10 mg/kg PTZ ip every 10 minutes until SE occurred,apoint charactered by a loss of postural control and tonic-clonic seizures.Rats in control group received the same number of saline injections.Rats in NIM group were injected NIM(2.5 mg/kg) intraperitoneally 15 min before the injection of PTZ.Rats in every group were killed at 30 minutes,1 hour,3 hours,12 hours,24 horus,72 hours and 7 days after status epilepsy respectively and the hippocampus were dissected.The expression of ERK and P-ERK in the hippocampus were detected by Western blot.Results Nimodipine attenuated the convulsion of PTZ-induced status epilepsy.There was dynamic expression of P-ERK in SE group.In NIM group,the expression of P-ERK was markedly increased than that of SE group at 30 min,1h,3h,12h,24h,72h,and 7d (3.26 ±0.95 vs 2.56 ±0.82 at 30 min,P＜0.05).Conclusion Nimodipine attenuates the convulsion of PTZ-induced status epilepsy with increased expression of phosphated-ERK in the hippocampus of rats.

Objective To explore the effects of luteolin on cognition function in pentylenetetrazol (PTZ)-induced epileptic rats and related mechanism.Methods Fifty male SD rats were randomly divided into a normal control group(n=8), a model group(n=12), and groups of 25, 50 mg/kg luteolin(both ofn=11), as well as 100 mg/kg luteolin group(n=8). Those rats were given different doses of luteolin (25, 50 and 100 mg/kg, daily, intragastric administration) for 36 consecutive days. Similarly, rats of the normal control group and the model group were given 0.5% sodium carboxymethyl cellulose suspension liquid via intragastric administration. Thirty minutes later, a model of epilepsy was induced using PTZ (40 mg/kg, daily) via intraperitoneal injection except the control group. Learning and memory of rats were evaluated by Morris water maze and novel objective recognition trials(including escape latency and recognition index). The levels of CaM and CaMPK were determined by ELISA methods, and expression of Ras proteins in the hippocampus were detected by Western Blot.Results Compared with the model group, luteolin treatment groups significantly shorten the escape latency(28.51 ± 3.84 s, 19.77 ± 5.41 s, 14.86 ± 2.76 svs. 37.08 ± 5.18 s) in the Morris water maze, and increased recognition index(18.77% ± 2.02%, 25.06% ± 4.32%, 31.92% ± 2.65%vs. 13.87% ± 2.14%) in the novel objection trial(P<0.05 orP<0.01). Meanwhile, CaM(140.33 ± 13.52 ng/L, 124.26 ± 9.97 ng/L, 113.52 ± 11.57 ng/Lvs. 158.36 ± 10.68 ng/L) and CaMPK(8.25 ± 1.37 ng/ml, 7.69 ± 0.84 ng/ml, 6.74 ± 0.93 ng/mlvs. 9.87 ± 1.02 ng/ml) were significantly decreased(P<0.05 orP<0.01). What’s more, the expression of Ras proteins(0.99 ± 0.08, 0.76 ± 0.07, 0.52 ± 0.07vs. 1.58 ± 0.12) was obviously decreased compared with the model group(P<0.05 orP<0.01).Conclusion Luteolin could effectively improve the cognition dysfunction of epileptic rats, and the mechanism might be relevant to regulate the CaM-CaMPK signaling pathway via down-regulation of CaM, CaMPK, as well as Ras protein.

Objective To evaluate the efficacy of salvage radiotherapy for supraclavicular lymph node metastasis ( SLNM) after initial treatment in patients with esophageal cancer. Methods A total of 117 patients with SLNM after radical resection for esophageal cancer were enrolled as subjects from 2006 to 2012. All patients received three?dimensional radiotherapy with 1. 8?2. 0 Gy per cycle, 5 cycles a week. The survival rates were calculated using the Kaplan?Meier method and analyzed using the log?rank test. The Cox model was used for multivariate analysis. Results The follow?up rate was 100%. In all the patients, the 1?and 3?year overall survival (OS) rates were 38. 5% and 14. 1%, respectively. The 1?and 3?year OS rates were significantly higher in patients treated with salvage radiotherapy or radiochemotherapy ( n=100) than in patients without any salvage treatment (n=17)(42% vs. 18%,P=0. 008;17% vs. 0%, P=0. 008). The patients treated with radiochemotherapy ( n=32) had significantly higher 1?and 3?year OS rates than those treated with radiotherapy alone (n=68)(59% vs. 34%, 36% vs. 11%, P=0. 002) or without any salvage treatment (n=17)(59% vs. 18%, 36% vs. 0%, P=0. 002). Patients without visceral metastasis (n=80) had significantly higher 1?and 3?year OS rates than those with visceral metastasis ( n=37) ( 44% vs. 27%, P=0. 002;22% vs. 0%,P=0. 002) . Patients with supraclavicular doses of ≥60 Gy in salvage radiotherapy ( n=75) had significantly higher 1?and 3?year OS rates than those with supraclavicular doses of<60 Gy in salvage radiotherapy ( n=25) ( 75% vs. 25%,P=0. 000;24% vs. 8%,P=0. 000) . The multivariate analysis using the Cox model showed that supraclavicular doses of ≥60 Gy, mediastinal metastasis, visceral metastasis, and salvage treatment method were independent factors for survival ( P=0. 001,0. 015,0. 009, 0. 025) . Conclusions Salvage radiotherapy can improve the survival of patients with SLNM in esophageal cancer. Salvage radiotherapy or radiochemotherapy is highly recommended for patients with SLNM alone. A radiation dose of ≥60 Gy in salvage radiotherapy improves survival in patients.

Photosynthetic CO(2) fixation is the ultimate source of organic carbon on earth and thus is essential for crop production and carbon sequestration. Ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) catalyzes the first step of photosynthetic CO(2) fixation. However, the extreme low carboxylation efficiency of Rubisco makes it the most attractive target for improving photosynthetic efficiency. Extensive studies have focused on re-engineering a more efficient enzyme, but the effort has been impeded by the limited understanding of its structure-function relationships and the lack of an efficient selection system towards its activity. To address the unsuccessful molecular engineering of Rubisco, we developed an Escherichia coli-based activity-directed selection system which links the growth of host cell solely to the Rubisco activity therein. A Synechococcus sp. PCC7002 Rubisco mutant with E49V and D82G substitutions in the small subunit was selected from a total of 15,000 mutants by one round of evolution. This mutant showed an 85% increase in specific carboxylation activity and a 45% improvement in catalytic efficiency towards CO(2). The small-subunit E49V mutation was speculated to influence holoenzyme catalysis through interaction with the large-subunit Q225. This interaction is conserved among various Rubisco from higher plants and Chlamydomonas reinhardtii. Knowledge of these might provide clues for engineering Rubisco from higher plants, with the potential of increasing the crop yield.
Amino Acid Substitution ; Bacterial Proteins ; chemistry ; genetics ; Carbon Dioxide ; chemistry ; Directed Molecular Evolution ; Escherichia coli ; growth & development ; Ribulose-Bisphosphate Carboxylase ; chemistry ; genetics ; Synechococcus ; enzymology

Objective:To measure the microdosimetric spectrum of carbon ion beam and calculate the relative biological effect (RBE) distribution, so as to provide reference for radiotherapy microdosimetric research.Methods:A silicon on insulator (SOI) microdosimeter was used to measure the microdosimetric spectrum of 12C ion beam, at 260 MeV/u, provided by Lanzhou Heavy Ion Accelerator National Laboratory. The measured pulse amplitude spectrum was converted to obtain the dose distribution. The microdosimetric spectra and RBE values at different polymethyl methacrylate depths were measured by the combination of different thickness PMMA. Results:The microdosimetric spectra of 12C ion beam at 260 MeV/u were measured at different PMMA depths, and the relationship between dose line energy yD and RBE and different PMMA depths was also obtained. The measurement result showed that the RBE value reached a peak of 2.6 at the PMMA depth of 116.5 mm, and decreased rapidly after the Bragg peak. However, the RBE value was still 1.3 at the trailing point, which was about twice as much as the entrance of the flat zone. Conclusions:This paper provides basic data for carbon ion beam microdosimetric spectroscopy through measurement. The RBE value of 12C ion beam gradually rises and reaches a peak with the increase of PMMA depth. After the Bragg peak position, it drops rapidly, but the biological effect at the tail cannot be ignored. At the same time, it reflects the dose fraction caused by different line energy intervals, and provides a reference for assessing the risk of heavy ion therapy for secondary cancer.

5-Aminolevulinic acid is the key intermediate of the tetrapyrrole biosynthesis pathway in organisms and has broad application potentials. This review summarized and discussed recent progress in microbial production of 5-aminolevulinic acid, including screening, isolation and mutation of microbes to produce 5-aminolevulinic acid; microbial whole-cell transformation to synthesize 5-aminolevulinic acid depending on the C4 pathway; construction of high-yield 5-aminolevulinic acid producing strains by metabolic engineering. Finally, future research directions in microbial production of 5-aminolevulinic acid were addressed.
Aminolevulinic Acid ; metabolism ; Escherichia coli ; genetics ; metabolism ; Metabolic Engineering ; Mutation ; Rhodobacter sphaeroides ; genetics ; metabolism