Xylanase is the key enzyme to degrade xylan that is a major component of hemicellulose. The enzyme has potential industrial applications in the food, feed, paper and flax degumming industries. The use of xylanases becomes more and more important in the paper industry for bleaching purposes. Xylanases used in the pulp bleaching process should be stable and active at high temperature and alkaline pH. Thermophilic and alkalophilic xylanases could be obtained by screening the wild type xylanases or engineering the mesophilic and neutral enzymes. In this paper, we reviewed recent progress of screening of the thermophilic and alkalophilic xylanases, molecular mechanism of thermal and alkaline adaptation and molecular engineering. Future research prospective was also discussed.
Endo-1,4-beta Xylanases ; chemistry ; Enzyme Stability ; Hot Temperature ; Hydrogen-Ion Concentration ; Paper ; Protein Engineering

Cystic neoplasms of the pancreas are rare lesions,usually without typical clinical manifestations.This article summarizes the clin-icopathological features and surgical treatment of common cystic neoplasms of the pancreas,including serous cystic neoplasm (SCN),mu-cinous cystic neoplasm (MCN),intraductal papillary mucinous neoplasm (IPMN),and solid pseudopapillary neoplasm (SPN).The clini-copathological features are independent prognostic factors for patients.More attention should be paid to correct diagnosis and appropriate sur-gical strategy for each cystic neoplasm of the pancreas.

In the aromatic amino acid biosynthetic pathway 3-dehydroshikimate (DHS) is a key intermediate. As a potent antioxidant and important feedstock for producing a variety of important industrial chemicals, such as adipate and vanillin, DHS is of great commercial value. Here, in this study, we investigated the effect of the co-expression of aroFFBR (3-deoxy-D-arabino-heptulosonate 7-phosphate synthase mutant with tyrosine feedback-inhibition resistance) and tktA (Transketolase A) at different copy number on the production of DHS. The increased copy number of aroFFBR and tktA would enhance the production of DHS by the fold of 2.93. In order to further improve the production of DHS, we disrupted the key genes in by-product pathways of the parent strain Escherichia coli AB2834. The triple knockout strain of ldhA, ackA-pta and adhE would further increase the production of DHS. The titer of DHS in shake flask reached 1.83 g/L, 5.7-fold higher than that of the parent strain E. coli AB2834. In 5-L fed-batch fermentation, the metabolically engineered strain produced 25.48 g/L DHS after 62 h. Metabolically engineered E. coli has the potential to further improve the production of DHS.
3-Deoxy-7-Phosphoheptulonate Synthase ; genetics ; Amino Acids, Aromatic ; biosynthesis ; Biosynthetic Pathways ; Escherichia coli ; genetics ; metabolism ; Fermentation ; Metabolic Engineering ; Shikimic Acid ; analogs & derivatives ; metabolism ; Transketolase ; genetics

Objective The Toxicology study of Tibetan medicine MNXT granules was observed to provide basis for clinical safe medication.Methods The acute toxicity test in mice was conducted with the oral maximum-tolerated dosage,and then toxicity reaction and death situations in mice at 14d after the intragastric administration (ig) one day at 3 times was observed; Long-term toxic test:the does of MNXT granule 13.23 g/kg · d-1,6.667 g/kg· d-1,3.33 g/kg· d-1 (equivalent 100,50,25 times of the clinical dosage) were continuous administered to medicating groups for 30 days,and blank group was given distilled water instead.The rats'behavior,appearance,food intake,water intake,body weight were observed,and the blood,blood biochemical parameters,the main organ coefficient,anatomical,pathological morphology were determined at 30d after administration and 15d after withdrawal.Results The maximum study medication dose of Tibet an medicine MNXT granule was 39 g/kg (equivalent to 300 times the clinical dose) and the mice had not any adverse reaction.Long-term toxicity test:the rats' blood and blood biochemical parameters,the main organ coefficient,anatomical,pathological morphology had not significant differences compared with the blank grou? during the 30d administration and 15d withdrawal.Conclusion Toxicity of the Tibetan medicine MNXT granules was not observed in acute or long-term toxicity test.

Objective To understand laboratory diagnosis and clinical characteristics of human immunodeficiency virus (HIV ) infection and AIDS patients in three comprehensive hospitals .Methods Laboratory diagnosis and clinical characteristics dates of people living with HIV/AIDS patients consulted in Chongqing Emergency Medical Center between 2007 to 2013 were retrospective‐ly analyzed .Results Totally 47 355 cases were carried HIV antibody screening during 7 years ,179 cases of HIV antibody were positive in preliminary screening ,171 cases were confirmed as positive .Among 5 cases of HIV antibodies result unconfirmed ,2 ca‐ses were followed up ,1 case was ruled out HIV infection ,1 case was converted to HIV antibody positive .People living with HIV al‐ways merging double or multiple infection with hepatitis b virus (HBV) ,hepatitis c virus (HCV) and treponema pallidum (TP) and so on .People living with HIV aged from 18 to 86 years old ,9 .36% was over 60 years old .Most patient has two or more clinical manifestations when consulted a doctor .Conclusion There were false‐positive of HIV antibody preliminary screening ,HIV anti‐body positive results must be confirmed by Western blot confirmatory test .Uncertainty of HIV antibody results should be judged by regularly follow‐up or combining with other detection methods ,epidemiological data .Routine HIV antibody screening should be adopt for HBV ,HCV and TP infection .Elder patients should not be ignored .Clinical specificity of HIV/AIDS is not strong ,it is need to be valued and identified from other cause similar symptoms of diseases caused by phase identification ,in order to reduce missed diagnosis and misdiagnosis .

Objective: To introduce electroacupuncture (EA) treatment on cervical spondylosis radiculopathy (CSR) at home and abroad in the prior ten years. Methods: EA, combined EA and other treatments for NCS are classified and analyzed. Results: The most commonly used acupoints are JiaJi (Ex-B2), Fengchi (GB 20), Waiguan (TE 5), Quchi (LI 11). EA is widely applied to treat CSR because of its definite therapeutic effects and safety. Conclusion: The validity of other evaluation indexes needs to be proved by more rigorously designed randomized controlled trials (RCT) with scientific methods.

Objective To investigate the value of combined detection of multi-tumor markers in the diagnosis of primary hepatocellular carcinoma (HCC) and to establish the discriminant equation. Methods Using a protein chip, 12 tumor markers in the serum from 98 patients with HCC and 67 patients with benign liver diseasewho had been admitted to Daping Hospital from November 2003 to April 2006, and 46 healthy individuals during he same period were analyzed. A discriminant equation was established to discriminate primary HCC from benign liver diseases. All the data were processed by variance analysis and chi-square test. Results The positive rates of the tumor markers were 89% (87/98) in patients with primary HCC, 19% (13/67) in patients with benign liver disease and 4% (2/46) in healthy individuals. There was statistical difference in the serum level of alpha-fetoprotein (AFP), eareinoembryonic antigen (CEA), ferritin (FER), CA19-9 and CA125 among the 3 groups (F =59.530, 40.472, 31.708, 75. 897, 153.066, P <0.05). Combined detection of AFP, CEA, FER, CA19-9 and CA125 improved the diagnostic accordance rate to 89%, which was significandy higher than the diagnostic accordance rate (64%) when only AFP was detected (X2 = 16.362, P <0.05). The accuracy of the discriminant equation was 90%. Conclusions Combined detection of multi-tumor markers is superior to AFP detection. Combined detection of multi-tumor markers can be used in screening of the HCC patients in HCC high risk population and in the early diagnosis of primary HCC.

ObjectiveTo evaluate setup errors of image guided radiation therapy (IGRT) for body tumors immbilized with vacuum cushions and localized with final isocenter marked method using kilovoltage cone beam CT (KVCBCT).MethodsA retrospective study has been carried out for 223 patients from March 2009 to April 2011.All patients were immobilized with vacuum cushions and localized with final isocenter marked method in Philips PQS CT or Philips Brilliance CT Big Bore scanner,which were equipped with LAP movable laser systems. The CT images were transferred to a Varian Eclipse workstation for contouring and treatment planning.Before irradiation,a KVCBCT scan was performed and image registration was done on a Varian iX linear accelerator via OBI system.Each set of setup errors in right-left ( RL),superior-inferior (SI),and anterior-posterior (AP) directions were gathered.An independent-samples t-test statistical analysis was conducted with the 758 sets of data using SPSS 16.0.Results The statistical analysis showed that setup errors from the 758 datasets were depicted a Gaussian distribution.The system errors ± random errors in RL,SI and AP were ( -0.5 ±2.8) mm,(0.0±3.0) mm and (0.4±3.4)mm,respectively.Referring to the formula for planning target volume margin calculation,M =2.5Σ + 0.7δ,the margins were calculated as 3.2,2.1 and 3.4 mm,respectively.ConclusionsThe margins derived from this retrospective study have confirmed the premise that the treatment plans were executed in patients with high reliability,thereby created a high sense of confidence for the clinicians.

Objective To understand the characteristics of problem behaviors among junior middle school students in northern Guizhou rural areas to provide reference for formulating the intervention measures .Methods The Chinese middle school students mental health scale and the self-made externalizing behavior problem questionnaire were adopted to perform the questionnaire sur-vey on left-behind kids of 6 junior middle schools .Results In the implicit problem behavior ,the scores of girls in hostility ,interper-sonal ,depression factor ,anxiety and total score were higher than those of boys ,and the each factor score was increased with grade ;in the explicit behavioral problems ,the occurrence rates of smoking ,drinking and gambling in boys were higher ,the detection rates of smoking and gambling were higher than those in students ,the occurrence rates of suicidal idea and leaving from home idea in students were 13 .1% and 22 .2% respectively ,in which the occurance rates of girls were higher than those in boys .The detection rate of sex related behaviors in boys was higher than that in girls .Conclusion The problem behaviors appear the gender and grade differences among left-behind kids in northern Guizhou rural areas .The differential mental health education should be carried out according to different target behaviors .

Rhamnolipid biosurfactant is mainly produced by Pseudomonas aeruginosa that is the opportunistic pathogenic strain and not suitable for future industrial development. In order to develop a relatively safe microbial strain for the production of rhamnolipid biosurfactant, we constructed engineered Escherichia coli strains for rhamnolipid production by expressing different copy numbers of rhamnosyltransferase (rhlAB) gene with the constitutive synthetic promoters of different strengths in E. coli ATCC 8739. We further studied the combinatorial regulation of rhlAB gene and rhaBDAC gene cluster for dTDP-1-rhamnose biosynthesis with different synthetic promoters, and obtained the best engineered strain-E. coli TIB-RAB226. Through the optimization of culture temperature, the titer of rhamnolipd reached 124.3 mg/L, 1.17 fold higher than that under the original condition. Fed-batch fermentation further improved the production of rhamnolipid and the titer reached the highest 209.2 mg/L within 12 h. High performance liquid chromatography-mass spectrometry (LC-MS) analysis showed that there are total 5 mono-rhamnolipid congeners with different nuclear mass ratio and relative abundance. This study laid foundation for heterologous biosynthesis of rhanomilipd.
Bacterial Proteins ; genetics ; Batch Cell Culture Techniques ; Decanoates ; Escherichia coli ; metabolism ; Fermentation ; Glycolipids ; biosynthesis ; Hexosyltransferases ; genetics ; Industrial Microbiology ; methods ; Multigene Family ; Promoter Regions, Genetic ; Pseudomonas aeruginosa ; Rhamnose ; analogs & derivatives ; biosynthesis ; Surface-Active Agents ; metabolism