Machine learning on MRI radiomic features: identification of molecular subtype alteration in breast cancer after neoadjuvant therapy.

OBJECTIVES: Recent studies have revealed the change of molecular subtypes in breast cancer (BC) after neoadjuvant therapy (NAT). This study aims to construct a non-invasive model for predicting molecular subtype alteration in breast cancer after NAT. METHODS: Eighty-two estrogen receptor (ER)-negative/ human epidermal growth factor receptor 2 (HER2)-negative or ER-low-positive/HER2-negative breast cancer patients who underwent NAT and completed baseline MRI were retrospectively recruited between July 2010 and November 2020. Subtype alteration was observed in 21 cases after NAT. A 2D-DenseUNet machine-learning model was built to perform automatic segmentation of breast cancer. 851 radiomic features were extracted from each MRI sequence (T2-weighted imaging, ADC, DCE, and contrast-enhanced T1-weighted imaging), both in the manual and auto-segmentation masks. All samples were divided into a training set (n = 66) and a test set (n = 16). XGBoost model with 5-fold cross-validation was performed to predict molecular subtype alterations in breast cancer patients after NAT. The predictive ability of these models was subsequently evaluated by the AUC of the ROC curve, sensitivity, and specificity. RESULTS: A model consisting of three radiomics features from the manual segmentation of multi-sequence MRI achieved favorable predictive efficacy in identifying molecular subtype alteration in BC after NAT (cross-validation set: AUC = 0.908, independent test set: AUC = 0.864); whereas an automatic segmentation approach of BC lesions on the DCE sequence produced good segmentation results (Dice similarity coefficient = 0.720). CONCLUSIONS: A machine learning model based on baseline MRI is proven useful for predicting molecular subtype alterations in breast cancer after NAT. KEY POINTS: • Machine learning models using MRI-based radiomics signature have the ability to predict molecular subtype alterations in breast cancer after neoadjuvant therapy, which subsequently affect treatment protocols. • The application of deep learning in the automatic segmentation of breast cancer lesions from MRI images shows the potential to replace manual segmentation..

Stablization of ACOs by NatB mediated N-terminal acetylation is required for ethylene homeostasis.

N-terminal acetylation (NTA) is a highly abundant protein modification catalyzed by N-terminal acetyltransferases (NATs) in eukaryotes. However, the plant NATs and their biological functions have been poorly explored. Here we reveal that loss of function of CKRC3 and NBC-1, the auxiliary subunit (Naa25) and catalytic subunit (Naa20) of Arabidopsis NatB, respectively, led to defects in skotomorphogenesis and triple responses of ethylene. Proteome profiling and WB test revealed that the 1-amincyclopropane-1-carboxylate oxidase (ACO, catalyzing the last step of ethylene biosynthesis pathway) activity was significantly down-regulated in natb mutants, leading to reduced endogenous ethylene content. The defective phenotypes could be fully rescued by application of exogenous ethylene, but less by its precursor ACC. The present results reveal a previously unknown regulation mechanism at the co-translational protein level for ethylene homeostasis, in which the NatB-mediated NTA of ACOs render them an intracellular stability to maintain ethylene homeostasis for normal growth and responses.

Sodium starch octenyl succinate facilitated the production of water-soluble yellow pigments in Monascus ruber fermentation.

Natural water-soluble Monascus pigments (WSMPs) have been in increasing demand but have not been able to achieve industrial production due to the low production rate. This study aimed to improve the biosynthesis and secretion of extracellular yellow pigments (EYPs) through submerged fermentation with Monascus ruber CGMCC 10,910 supplemented with sodium starch octenyl succinate (OSA-SNa). The results demonstrated that the yield was 69.68% and 48.89% higher than that without OSA-SNa in conventional fermentation (CF) and extractive fermentation (EF), respectively. The mainly increased EYP components were Y3 and Y4 in CF, but they were mainly Y1 and Y2 as well as secreted intracellular pigments, including Y5, Y6, O1, and O2, in EF. Scanning electron microscopy analysis revealed that the mycelium presented an uneven surface profile with obvious wrinkles and small fragments with OSA-SNa. It was found that a higher unsaturated/saturated fatty acids ratio in the cell membrane resulted in increased permeability and facilitated the export of intracellular yellow pigments into the broth with OSA-SNa treatment. In addition, a higher NAD+/NADH ratio and glucose-6-phosphate dehydrogenase activity provided a reducing condition for yellow pigment biosynthesis. Gene expression analysis showed that the expression levels of the key genes for yellow pigment biosynthesis were significantly upregulated by OSA-SNa. This study provides an effective strategy to promote the production of WSMPs by microparticle-enhanced cultivation using OSA-SNa. KEY POINTS: • OSA-SNa addition facilitated the production of Monascus yellow pigments. • Mycelial morphology and membrane permeability were affected by OSA-SNa. • The key gene expression of yellow pigments was upregulated.

Inducing red pigment and inhibiting citrinin production by adding lanthanum(III) ion in Monascus purpureus fermentation.

Monascus pigments (MPs) are widely used natural colorants in Asian countries. The problems of low extracellular red pigment (ERP) and high citrinin remain to be solved in Monascus pigment production. The effect of lanthanum(III) ion (LaCl3) on Monascus purpureus fermentation was investigated in this study. The yields of ERP and biomass respectively reached maxima of 124.10 U/mL and 33.10 g/L by adding 0.4 g/L La3+ on the second day in the total 8-day fermentation; simultaneously, citrinin was decreased by 59.93% and 38.14% in the extracellular and intracellular fractions, respectively. Reactive oxygen species (ROS) levels were obviously improved by La3+ treatment, while the activities of catalase (CAT) and superoxide dismutase (SOD) were increased compared with the control. The ratio of unsaturated/saturated fatty acids in mycelia was increased from 2.94 to 3.49, indicating that the permeability and fluidity of the cell membrane were enhanced under La3+ treatment. Gene expression analysis showed that the relative expression levels of Monascus pigment synthesis genes (pksPT, mppB, mppD, MpFasB2, and MpPKS5) were significantly upregulated by La3+ treatment, and in contrast, the relative expression levels of citrinin synthesis genes (ctnA, pksCT and mppC) were markedly downregulated. This work confirmed that LaCl3 possesses the potential to induce red pigment biosynthesis and inhibit citrinin production in M. purpureus fermentation. KEY POINTS: • La3+ induced red pigment and inhibited citrinin production in Monascus fermentation. • La3+ regulated genes expression up for Monascus pigment and down for citrinin. • La3+ increased the UFAs in cell membrane to enhance the permeability and fluidity.

MAL62 overexpression enhances uridine diphosphoglucose-dependent trehalose synthesis and glycerol metabolism for cryoprotection of baker's yeast in lean dough.

BACKGROUND: In Saccharomyces cerevisiae, alpha-glucosidase (maltase) is a key enzyme in maltose metabolism. In addition, the overexpression of the alpha-glucosidase-encoding gene MAL62 has been shown to increase the freezing tolerance of yeast in lean dough. However, its cryoprotection mechanism is still not clear. RESULTS: RNA sequencing (RNA-seq) revealed that MAL62 overexpression increased uridine diphosphoglucose (UDPG)-dependent trehalose synthesis. The changes in transcript abundance were confirmed by quantitative reverse transcription-polymerase chain reaction (qRT-PCR) and enzyme activity assays. When the UDPG-dependent trehalose synthase activity was abolished, MAL62 overexpression failed to promote the synthesis of intracellular trehalose. Moreover, in strains lacking trehalose synthesis, the cell viability in the late phase of prefermentation freezing coupled with MAL62 overexpression was slightly reduced, which can be explained by the increase in the intracellular glycerol concentration. This result was consistent with the elevated transcription of glycerol synthesis pathway members. CONCLUSIONS: The increased freezing tolerance by MAL62 overexpression is mainly achieved by the increased trehalose content via the UDPG-dependent pathway, and glycerol also plays an important role. These findings shed new light on the mechanism of yeast response to freezing in lean bread dough and can help to improve industrial yeast strains.

Improving mycelial morphology and adherent growth as well as metabolism of Monascus yellow pigments using nitrate resources.

Mycelial adhesion affects cell growth and the production of water-soluble extracellular yellow pigment (EYP) in submerged fermentation with Monascus ruber CGMCC 10910. Two nitrates, NaNO3 and KNO3, were used as nitrogen sources for mitigating mycelial adhesion and improving the production of EYP in this study. The results showed that the adhesion of mycelia in the fermentation broth significantly decreased by adding 5 g/L NaNO3, which prevented mycelia from attaching to the inner wall of the Erlenmeyer flask. It was suggested that NaNO3 reduced the total amount of extracellular polysaccharides, increased extracellular proteins, and decreased the viscosity of the fermentation broth. Scanning electron microscopy (SEM) analysis revealed that the mycelial morphology was shorter and more dispersed and vigorous under NaNO3 conditions than under the control conditions. The biomass increased by 49.2% and 45.4% with 5 g/L NaNO3 and 6 g/L KNO3 treatment, respectively, compared with that of the control, and the maximum production of EYP was 267.1 and 241.8 AU350, which increased by 70.0% and 53.9% compared with that of the control, respectively. Simultaneously, the ratios of intracellular yellow pigment to orange pigment increased significantly with 5 g/L of NaNO3 addition (p < 0.05). Genetic analysis found that the expression levels of the key genes for Monascus pigment biosynthesis were significantly upregulated by NaNO3 addition (p < 0.05 or p < 0.01). This study provides an effective strategy for the production of water-soluble Monascus yellow pigments.Key Points• Nitrate addition decreased mycelial adhesion and improved cell growth in Monascus pigment fermentation.• The biosynthesis genes of water-soluble extracellular yellow pigment (EYP) were upregulated by nitrate addition.• The mycelial morphology was significantly influenced to enhance EYP biosynthesis with nitrate addition.

[An Epidemiological Survey on Echinococcosis in Yushu Prefecture of Qinghai Province].

Objective: To investigate the prevalence of echinococcosis in Yushu Prefecture of Qinghai Province in 2012. Methods: Two to three towns were selected in each of Chengduo, Nangqian, Qu malai, Yushu, Zaduo and Zhiduo Counties from June to August in 2012. Ultrasound examination was conducted for residents aged over 1 year, and ELISA was performed to detect serum antibody against Echinococcus. Visceral dissection was performed to detect hydatid infection in rodents and livestock. ELISA was used to detect Echinococcus antigen in collected dog feces. Results: A total of 7 025 residents received ultrasound examination, of whom 319 showed hydatid cysts with a morbidity rate of 4.54%. ELISA showed a serum antibody positive rate of 16.38% （457/2 790）. The mobidity of hydatid disease was highest in Chengduo County （7.41%, 181/2 444）, and the rate of serum antibody was highest in Yushu County （23.18%, 127/548）. The morbidity and serum antibody in males were 3.91% （118/3 018） and 13.93% （172/1 235） respectively, and those in females were 5.02% （201/4 007） and 18.33% （285/1 555）. In terms of age distribution, the morbidity was relatively higher in residents of 60- （8.39%, 38/453） and 40- years （6.61%, 67/1 014）; and the rate of serum antibody was highest in residents over 70 years （33.93%, 19/56）. In terms of occupation, the morbidity was relatively higher in herdsmen （5.28%, 252/4 777）, Herdsmen-peasants （6.52%, 24/368）, and religious workers（3.37%, 11/326）, while the rate of serum antibody was relatively higher in children（24%, 6/25）, religious workers （18.79%, 31/165） and herdsmen（18.34%, 328/1 788）. In terms of education level, the morbidity and the rate of serum antibody were both highest in the uneducated（5.04%, 41/4 779; 18.34%, 359/1 958, respectively）. In terms of residential pattern, the morbidity and the rate of serum antibody were both highest in those who were settled in winter and nomadic in summer （8.25%, 227/2 753; 19.48%, 158/811, respectively）. There were significant differences in the morbidity and the rate of serum antibody in aspects of residential region, sex, age, occupation, education level and residential pattern (P<0.05 or P<0.01). In 872 rodents detected, the Echinococcus hydatid rate was 0.46% （4/872）, while in 809 cattle and sheep detected, the Echinococcus hydatid rate was 10.14% （82/809）. The fecal antigen positive rate in 838 samples of dog feces was 10.74%（90/838）. Conclusion: It shows a high morbidity of hydatid diesease and serum antibody positive rate in residents, a high Echinococcus hydatid rate in cattle and sheep, and a high fecal antigen positive rate in dogs in Yushu Prefecture.

[Quality standard study on Tibetan medicine Gentianae Szechenyii Flos].

In order to efficiently control the quality of the Tibetan medicine Gentianae Szechenyii Flos, the quality standard was established in this study. The tests of water content, total ash and ethanol-soluble extractives of the crude drugs were carried out based on the methods recorded in appendix of Chinese Pharmacopeia (2010 edition, volume 1). The TLC method was established by using reference drug and gentiournoside A as reference substance, and a mixture of ethyl acetate-methanol-water-formic acid (7: 1.5: 1: 0.2) as the developing solvent system on silica gel G TLC plate. The content of gentiournoside A was assayed by HPLC on a Ultimate XB-C18 (4.6 mm x 250 mm, 5 µm) column, using methanol-water (0.02% phosphoric acid) (52:48) as the mobile phase at a flow rate of 1.0 mL x min(-1). The column temperature is 25 degrees C and the detection wavelength is at 240 nm. As a result, gentiournoside A and the other constituents were separated and presented the same fluorescence light comparing with the reference substance on TLC detected under the UV light(366 nm). The methodology validation for the assay of gentiournoside A showed that it was in a good linear correlation in the range of 10.01-400.32 mg x L(-1) with the regression equation of Y = 1 539.5X - 33.339 (r = 0.999 7), and the average recovery was 99.68% (RSD 1.92%). The mass fractions of gentiournoside A, water content, ethanol-soluble extractives of 19 batches samples were varied in the ranges of 14.48-31.51 mg x g(-1), 11.25% -12.74% and 24.21% - 31.60%, respectively, and total ash was 4.64% - 6.12% detected from 10 batches samples. The recommended standards of quantitative indexes are that the mass fractions of gentiournoside A and extractives are not less than 15.0 mg x g(-1) (1.5%) and 21.0%, respectively; the water and total ash are not more than 13.0% and 6.0%, respectively.

[Molecular identification of Tibetan medicine Qianghuoyu by CO I].

The CO I gene sequences of Qianghuoyu, Pachytriton labiatus and Gehyra mutilata were achieved by PCR amplification and bi-directional sequencing. Furthermore, a pair of specific primers SJYW1 and SJYW2 in the non-conservative district were designed through sequence alignment. The PCR reaction condition was established by changing the annealing temperature and cycle numbers. The results showed that 350 bp DNA fragment was amplified from Qianghuoyu in PCR with annealed temperature at 54 °C and the cycle number was 25 cycles, whereas not any DNA fragment was amplified from P. labiatus and G. mutilata under the same reaction condition. This method is well-performed in the identification of Qianghuoyu for its excellent specificity and repeatability.

[Quality standard study on Tibetan medicine Gentianae Urnulae Herba].

Gentianae Urnulae Herba, dried whole herb of Gentiana urnula,is a commonly used Tibetan medicine. However, only the character identification is used as quality control standard officially at present. As a part of project for the Chinese Pharmacopoeia (2015 edition), the quality standard of this species was established in this study. The tests of water content, total ash, acid-insoluble ash and ethanol-soluble extractives of the crude drugs were carried out following the methods recorded in appendix of Chinese Pharmacopeia (2010 edition, volume 1). The TLC identification method was established by using gentiournoside A as reference substance, and a mixture of ethyl acetate-methanol-water-formic acid(7:1. 5:1: 0. 2) as the developing solvent system on silica gel G TLC plate. The content of gentiournoside A was assayed by HPLC on an Agilent Zorbax SB-C18 (4.6 mm x 250 mm,5 µm) column, using acetonitrile-water (0.1% phosphoric acid) (26:74) as the mobile phase at a flow rate of 1.0 mL x min(-1). The column temperature is at 30 degrees C and the detection wavelength is at 240 nm. As a result, gentiournoside A and the other constituents were separated and presented the same fluorescence light comparing with the reference substance on TLC detected under the UV light(366 nm). The methodology validation for the assay of gentiournoside A showed that it was in a good linear correlation in the range of 0.009 95-0.398 g x L(-1) with the regression equation of Y = 1 467.1X +41.407(r = 0.999 9), and the average recovery was 98. 3% (RSD 2.2%). The mass fractions of gentiournoside A, water content, ethanol-soluble extractives of 15 batches samples were varied in the ranges of 0.175% -1.83%, 8.60% - 9.93% and 29.2% - 35.2%, respectively. Total ash and acid-insoluble ash were 10.2% - 17.2% and 5.26% - 10.8% detected from 10 batches samples. The recommended standards of quantitative indexes are that the mass fractions of gentiournoside A and extractives are not less than 0.80% and 26.0%, respectively; the water, total ash and acid-insoluble ash are not more than 12.0%, 15.0% and 8.0%, respectively.

[Survey on Echinococcosis in Maqing County of Qinghai Province].

OBJECTIVE: To understand the status of echinococcosis in Maqing County of Qinghai Province in order to facilitate echinococcosis control in this region. METHODS: Ultrasonic scanning and indirect hemagglutination assay were used to detect echinococcosis infection in residents >1 year old, according to the People's Republic of China Health Industry Standard--Diagnostic Criteria for Hydatid Disease (WS257-2006). Meanwhile, ELISA was used o detect the Echinococcus antigen in dog's feces collected in Youyun, Dangluo and Xiadawu townships. RESULTS: Ultrasonic scanning showed that the prevalence of hydatid disease in the residents was 7.4% (116/1 561), cystic hydatid disease 5.3% (82/1 561), alveolar hydatid disease 2.2% (34/1 561). The serum positive rate in human population was 23.8%(307/1 288). Of the 82 cases of cystic hydatid disease, 23 cases (28.1%) had the hydatid cyst with a diameter of >10 cm. The prevalence in males and females in the county was 5.3% (40/753) and 9.4% (76/808), respectively (P<0.05). Among populations with different occupations, the highest prevalence of hydatid disease fell into houseworkers (11/61, 18.0%), monks (5/41, 12.2%) and herdsmen (84/758, 11.1%). Among the age groups, the groups of >60 years (24/132, 18.2%) and 30-40 years (31/302, 10.3%) had higher prevalence of hydatid disease. The three townships with the higher prevalence were Youyun (29/247, 11.7%), Changmahe (6/63, 9.5%) and Dangluo (54/645, 8.4%). Of the 199 samples of dog's feces, 54 were positive for Echinococcus antigens (27.1%), with a positive rate of 40.4% (23/57) in Youyun towship, being significantly higher than in the other two (P<0.05). CONCLUSION: Maqin county is a co-endemic area of cystic echinococcosis and alveolar echinococcosis. The prevalence is higher in females and those over 60 years-old.

Two new schisdilactone-type compounds from Schisandra chinensis.

Two new schisdilactone-type compounds, respectively, named schisdilactone H (1) and schisdilactone I (2), were isolated from the stems of Schisandra chinensis. The structures and absolute configurations of these new compounds were elucidated by extensive spectroscopic analysis as well as time-dependent density functional theory electronic circular dichroism calculations.

Significance of NatB-mediated N-terminal acetylation of auxin biosynthetic enzymes in maintaining auxin homeostasis in Arabidopsis thaliana.

The auxin IAA (Indole-3-acetic acid) plays key roles in regulating plant growth and development, which depends on an intricate homeostasis that is determined by the balance between its biosynthesis, metabolism and transport. YUC flavin monooxygenases catalyze the rate-limiting step of auxin biosynthesis via IPyA (indole pyruvic acid) and are critical targets in regulating auxin homeostasis. Despite of numerous reports on the transcriptional regulation of YUC genes, little is known about those at the post-translational protein level. Here, we show that loss of function of CKRC3/TCU2, the auxiliary subunit (Naa25) of Arabidopsis NatB, and/or of its catalytic subunit (Naa20), NBC, led to auxin-deficiency in plants. Experimental evidences show that CKRC3/TCU2 can interact with NBC to form a NatB complex, catalyzing the N-terminal acetylation (NTA) of YUC proteins for their intracellular stability to maintain normal auxin homeostasis in plants. Hence, our findings provide significantly new insight into the link between protein NTA and auxin biosynthesis in plants.

Construction of the subtracted cDNA library of striatal neurons treated with long-term morphine.

OBJECTIVE: To construct a morphine tolerance model in primarily cultured striatal neurons, and screen the differentially expressed genes in this model using suppression subtractive hybridization (SSH). METHODS: Sbtracted cDNA libraries were constructed using SSH from normal primarily cultured striatal neurons and long-term morphine treated striatal neurons (10-5 mol/L for 72 hours). To check reliability of the cell culture model, RT-PCR was performed to detect the cAMP-responsive element-binding protein (CREB) mRNA expression. The subtracted clones were prescreened by PCR. The clones containing inserted fragments from forward libraries were sequenced and submitted to GenBank for homology analysis. And the expression levels of genes of interest were confirmed by RT-PCR. Results CREB mRNA expression showed a significant increase in morphine treated striatal neurons (62.85 ± 1.98) compared with normal striatal neurons (28.43 ± 1.46, P < 0.01). Thirty-six clones containing inserted fragments were randomly chosen for sequence analysis. And the 36 clones showed homology with 19 known genes and 2 novel genes. The expression of 2 novel genes, mitochondrial carrier homolog 1 (Mtch1; 96.81 ± 2.04 vs. 44.20 ± 1.31, P < 0.01) and thymoma viral proto-oncogene 1 (Akt1; 122.10 ± 2.17 vs. 50.11 ± 2.01, P < 0.01), showed a significant increase in morphine-treated striatal neurons compared with normal striatal neurons. CONCLUSIONS: A reliable differential cDNA library of striatal neurons treated with long-term morphine is constructed. Mtch1 and Akt1 might be the candidate genes for the development of morphine tolerance.

Function of histone H2B monoubiquitination in transcriptional regulation of auxin biosynthesis in Arabidopsis.

The auxin IAA is a vital plant hormone in controlling growth and development, but our knowledge about its complicated biosynthetic pathways and molecular regulation are still limited and fragmentary. cytokinin induced root waving 2 (ckrw2) was isolated as one of the auxin-deficient mutants in a large-scale forward genetic screen aiming to find more genes functioning in auxin homeostasis and/or its regulation. Here we show that CKRW2 is identical to Histone Monoubiquitination 1 (HUB1), a gene encoding an E3 ligase required for histone H2B monoubiquitination (H2Bub1) in Arabidopsis. In addition to pleiotropic defects in growth and development, loss of CKRW2/HUB1 function also led to typical auxin-deficient phenotypes in roots, which was associated with significantly lower expression levels of several functional auxin synthetic genes, namely TRP2/TSB1, WEI7/ASB1, YUC7 and AMI1. Corresponding defects in H2Bub1 were detected in the coding regions of these genes by chromatin immunoprecipitation (ChIP) analysis, indicating the involvement of H2Bub1 in regulating auxin biosynthesis. Importantly, application of exogenous cytokinin (CK) could stimulate CKRW2/HUB1 expression, providing an epigenetic avenue for CK to regulate the auxin homeostasis. Our results reveal a previously unknown mechanism for regulating auxin biosynthesis via HUB1/2-mediated H2Bub1 at the chromatin level.

1,4,8,11-Tetra-kis(carboxy-meth-yl)-5,5,7,12,12,14-hexa-methyl-4,11-diaza-1,8-diazo-niacyclo-tetra-decane dichloride dihydrate.

The title compound, C(24)H(46)N(4)O(8) (2+)·2Cl(-)·2H(2)O, was synthes-ized by the hydrolysis of tetra-ethyl 2,2',2'',2'''-(5,5,7,12,12,14-hexa-methyl-1,4,8,11-tetra-azacyclo-tetra-decane-1,4,8,11-tetra-yl) tetra-acetate in hydro-chloric acid solution. The crystal structure of the title compound consists of a 14-membered C(10)N(4) centrosymmetric cationic macrocycle which inter-acts with the chloride ions and water mol-ecules of crystallization to give a three-dimensional hydrogen-bonded network.

[An epidemiological survey on hydatid disease in Yushu Prefecture of Qinghai Province].

Local inhabitants in 8 towns/townships of the counties Yushu, Zhiduo and Chengduo were examined with serology and ultrasound in 2006. Among 2 251 people tested by indirect hemagglutination (IHA), 207 showed anti-hydatid IgG positive (9.2%). Ultrasound examination found 106 cases out of 2581 people, with a morbidity of 4.1%. Females showed higher sero-positive rate (11.3%) and morbidity rate (5.0%) than males (6.6% and 3.0% respectively). The highest sero-positive rate was in the group of 40-49 years old (16.4%). The morbidity rate increased with age, with the highest rate (15.5%) in the group of 60 years old and above. Occupationally, those involved in semi-agriculture and semi-animal husbandry showed highest sero-positive rate and morbidity rate, 21.5% and 11.4% respectively. The survey demonstrated that the prevalence of hydatid disease in human population is at a high level in Yushu Tibetan Autonomous Prefecture.

Highly sensitive and selective sensor for sunset yellow based on molecularly imprinted polydopamine-coated multi-walled carbon nanotubes.

Polydopamine (PDA) can be formed by monomeric self-polymerization in water. This convenient behavior was exploited to prepare a molecularly imprinted polymer (MIP) layer on the surface of multi-walled carbon nanotubes (MWCNTs) with sunset yellow (SY) as a template molecule. The prepared nanocomposites were characterized, and their electrochemical behavior towards SY was investigated. Under the optimized conditions, a glassy carbon electrode modified with the imprinted nanocomposite showed a highly selective and ultrasensitive electrochemical response to SY compared with the performance of control electrodes and previously reported electrochemical sensors for SY. The improved behavior of the developed sensor can be attributed to its superficial highly matched imprinted cavities on the excellent electrocatalytic matrix of MWCNTs and the electronic barrier of the non-imprinted PDA to outside molecules. The fabricated sensor expressed a linear relationship to SY concentrations from 2.2nM to 4.64µM with a detection limit of 1.4nM (S/N = 3). The sensor also exhibited excellent selectivity for SY over its structural analogs, good stability, and adequate reproducibility. The prepared sensor was successfully used to detect SY in real spiked samples. This methodology has potential application value and may be readily adapted to design other PDA-based MIP sensors.

[An epidemiological survey on echinococcosis in Zhiduo County of Qinghai Province].

The survey was carried out in July, 2006 in Zhiduo County. The IHA and ELISA positive rate in human population was 4.5% (42/933) and 8.2% (76/931) respectively. Ultrasonography revealed a morbidity of 3.4% (33/979) with 3.2% Echinococcus granulosus and 0.2% of E. multilocularis respectively. Animal dissection showed an infection rate of 15.1% (14/93) in pikas with one infected by E. shiquicus proved by molecular biology. Coproantigen rate by ELISA was 62% (12/193) in dogs and 35.7% (5/14) in wolves. The results indicated that Zhiduo County is a mixed endemic area for echinococcosis.

[Study on the purification and scavenging free radical activity of water soluble polysaccharide of leave in Hippohae rhamnoides L].

The crude polysaccharide was extracted from Leave in Hippohae rhamnoides L. with hot water, and precipitated by ethanol. The crude polysaccharide has been fractionated by acidic ethanol. Three fractions (SJ1, SJ2, SJ3) were got respectively. SJ2 deproteinizationed by the combined methods of enzyme and Seveage, purified by DEAE-Sephadex A-25 gel filtration. PC analysis indicated that SJ22 is composed of Xyl,Ara,Glc,Gal,GaL A. The identification of purify by Sepharose CL-4B, paper chromatography and cellulous acetate electrophoresis showed it was homogeneous. Typical absorption of polysaccharides was shown in its IR spectrum. It contained a-glucosidic bonds by IR analysis. It had typical absorption of protein by UV scaning. SJ22 is first isolated from Leave in Hippohae rhamnoides L Scavenging free radical experiment showed that SJ22 was effective in scavenging superoxideradical and hydroxylradical, but only a little effective in scavenging lipid radical.