[News report of People's Daily (1949-1979) for TCM practitioners:Changes in the status of TCM groups].

The construction and analysis of the topic of traditional Chinese medicine is an important social and cultural landscape since the founding of New China, and media for party afairs is an important field for this process. Authoritative media such as People's Daily expressed respect to TCM practitioners, reflected the national system, urban-rural relations, cultural concepts, etc. behind the development of TCM, and clarified the determination and confidence of the Party and the country to adhere to the development of TCM through its content,specific situations and line of reasoning logic.

Susceptibility of Bacillus subtilis to Zinc Oxide Nanoparticles Treatment.

Aim: With the characteristics such as low toxicity, high total surface, ability to inhibit the growth of pathogenic microorganisms, zinc oxide nanoparticles (ZnO NPs), as one of the metallic nanoparticles, have been chosen as an antibacterial agent to treat various skin infections. The present study was aimed to determine the antibacterial potential of ZnO NPs on Bacillus subtilis, the Gram-positive bacterium that can cause skin and wound infections. Methods: B. subtilis was exposed to 5 to 150 µg/mL of ZnO NPs for 24 h. The parameters employed to evaluate the antimicrobial potential of ZnO NPs were the growth inhibitory effect on B. subtilis, the surface interaction of ZnO NPs on the bacterial cell wall, and also the morphological alterations in B. subtilis induced by ZnO NPs. Results: The results demonstrated a significant (p <0.05) inhibition of ZnO NPs on B. subtilis growth and it was in a dose-dependent manner for all the tested concentrations of ZnO NPs from 5 to 150 µg/mL at 24 h. Fourier transformed infrared (FTIR) spectrum confirmed the involvement of polysaccharides and polypeptides of bacterial cell wall in surface binding of ZnO NPs on bacteria. The scanning electron microscopy (SEM) was used to visualize the morphological changes, B. subtilis illustrated several surface alterations such as distortion of cell membrane, roughening of cell surface, aggregation and bending of cells, as well as, the cell rupture upon interacting with ZnO NPs for 24 h. Conclusion: The results indicated the potential of ZnO NPs to be used as an antibacterial agent against B. subtilis. The findings of the present study might bring insights to incorporate ZnO NPs as an antibacterial agent in the topical applications against the infections caused by B. subtilis.

Effect of N-acetyl-l-methionine supplementation on lactation performance and plasma variables in mid-lactating dairy cows.

The objective of current study was to investigate the effect of N-acetyl-l-methionine (NALM) supplementation on lactation performance and plasma variables in mid-lactating dairy cows. Forty-eight multiparous cows were blocked into 12 groups based on parity, days in milk, and milk production and were randomly assigned to 1 of the 4 treatments: 0, 15, 30, or 60 g/d of NALM per cow to supplement the basal diet. The experiment was conducted over a 13-wk period, with the first week as adaptation. The yields of milk, fat-corrected milk, and milk lactose were increased quadratically, and energy-corrected milk yield tended to increase with increased NALM supplementation in a quadratic manner. The dry matter intake, milk protein yield, milk fat yield, contents of milk composition (protein, fat, lactose, total solids, and milk urea nitrogen), feed efficiency, and body weight change were not affected by NALM supplementation. In addition, plasma methionine concentration was increased quadratically, and proline, total nonessential AA, and total AA concentrations were significantly higher in the 30 g/d group compared with that of the control group. However, other AA and total essential AA concentrations were not affected with supplementation of NALM. Adding NALM increased concentrations of total protein and globulin in plasma, but decreased plasma urea nitrogen concentration in a quadratic manner. Meanwhile, plasma malonaldehyde concentration decreased linearly as doses of NALM addition increased. Our results suggested that the supplementation of NALM improved milk yield and protein synthesis in the liver, and lowered lipid peroxidation in mid-lactating dairy cows.

Short communication: Effects of dietary addition of N-carbamoylglutamate on milk composition in mid-lactating dairy cows.

The present study was conducted to investigate the effect of N-carbamoylglutamate (NCG) on milk production and composition in mid-lactating Holstein dairy cows. Sixty multiparous cows with a mean body weight of 669 kg (standard deviation = 71) and 176 days in milk (standard deviation = 55) were blocked based on parity and milk production and randomly assigned into 4 treatments, a basal diet supplemented with 0, 10, 20, or 40 g of NCG/d per cow. Milk yield and composition were recorded weekly, whereas dry matter intake and plasma variables were determined every 2 wk. The results showed that the addition of NCG had no effect on the dry matter intake and milk yield of the cows. Milk fat content and yield increased linearly with NCG addition. The contents of milk protein and total solid also increased linearly in the cows fed NCG, whereas the yield of protein was not affected by the treatments. Conversely, dietary addition of NCG increased the plasma nitric oxide content in a quadratic manner. Moreover, addition of NCG linearly increased the plasma Arg content. Overall, the results indicate that dietary NCG addition increased the milk protein and fat contents, which improved the milk quality of lactating dairy cows.

[Clinical analysis of 76 cases of sentinel lymph node detection in cervical cancer and endometrial cancer].

Objective: To evaluate the feasibility and clinical value of identifying sentinel lymph node (SLN) and to assess possible factors associated with detection rate in both cervical cancer and endometrial cancer. Methods: Retrospective study of 76 cases (39 with cervical cancer and 37 with endometrial cancer) were conducted in Peking University People's Hospital. All patients underwent SLN biopsy with tracers of indocyanine green (ICG) and (or) carbon nanoparticles. All mapped SLN was resected and followed by procedures that systematic pelvic lymphadenectomy and hysterectomy according to National Comprehensive Cancer Network (NCCN) guidelines. All the lymph nodes were examined postoperatively for the routine paraffin section of hematoxylin and eosin (HE) staining. Detection rate, sensitivity and negative predictive value of SLN were calculated and factors associated with the detection rate were analyzed. Results: The overall detection rate was 95% (72/76), with 74% (56/76) positive bilaterally. The bilateral detection rate of SLN with combined technique was significantly higher than that with single technique (P<0.05). The difference of SLN detection rate between cervical and endometrial cancer patients were not significant (P>0.05). SLN were mostly recognized in obturator (32.1%, 114/355) and external iliac areas (32.4%, 115/355) in cervical cancer, and in external iliac (41.2%, 91/221) and obturator areas (39.4%,87/221) in endometrial cancer. Among 55 patients underwent systematic pelvic lymphadenectomy, the sensitivity of SLN detection was 75% and the negative predictive value was 96%. The sensitivity and negative predictive value were both 100% in patients with successfully bilateral mapped of SLN. Conclusion: s The overall detection rate of SLN in cervical and endometrial cancer is the highest with the combined technique of ICG and carbon nanoparticles. The detection rate and located regions of SLN are similar between cervical and endometrial cancer, and SLN are mostly recognized in the external iliac and obturator areas. The sensitivity and negative predictive value of SLN detection are high, especially when SLN are bilateral mapped.

Oral administration of tea saponins to relive oxidative stress and immune suppression in chickens.

The present study was designed to evaluate the effects of tea saponins on oxidative stress induced by cyclophosphamide in chickens. One hundred twenty chickens were randomly divided into 5 groups. Groups 3 to 4 received intramuscular injection of cyclophosphamide to induce oxidative stress and immunosuppression. After that, groups 2 and 4 were orally administered tea saponins in drinking water for 7 d. Then, groups 1 to 4 were immunized with a live, bivalent vaccine of Newcastle disease virus and infectious bronchitis virus. Blood samples were collected for analysis of oxidative parameters and specific antibody titers, and splenocytes were prepared for lymphocyte proliferative assay. The results showed that administration of tea saponins significantly increased total antioxidant capacity, total superoxide dismutase, catalase, glutathione peroxidase, glutathione, ascorbic acid, and α-tocopherol, and decreased malondialdehyde and protein carbonyl. Enhanced immune responses, such as lymphocyte proliferation induced by concanavalin A and lipopolysaccharides, and serum Newcastle disease virus- and infectious bronchitis virus-specific antibodies were also observed in chickens injected with or without cyclophosphamide. In addition, no side effects were found in chickens throughout the study. Therefore, tea saponins may be a potential agent to improve imunosuppression induced by oxidative stress in chickens.

[The decipher, annotation and textual research of 3 prescriptions for gynecopathy in the Tangut medical documents unearthed in Khara-Khoto].

The second part of Tangut medical documents (И(HB).No.6476) unearthed in Khara-Khoto is the "Prescriptions for gynecopathy" , which includes 15 prescriptions, all without title. Three of them could be named as "prescription for treating vulvae bleeding" , "prescription for treating blood conglomeration inside woman body" and "prescription for treating ceaseless hemorrhage" . One to five ingredients were used in the prescriptions, most of them are local medicines. The compounding of the prescriptions also reflects the characteristics of northwestern region, showing that the author were the local folk doctor of the Western Xia reign.

[Textual research on a prescription, "Pill of Semen Plantaginis" in the Tangut medical documents unearthed in Khara-Khoto].

A prescription, "Pill of Semen Plantaginisfor Treating All Diseases" (И(HB).N(O).4384) carried in the Tangut medical documents unearthed in Khara-Khoto was published in the 10(th)Volume of Heishuicheng Manuscript Collected in Russia. The prescription is composed of Herba Cistanches, Radix Achyranthis, Semen Plantaginis, white poria, Cortex Cinnamomi, Radix Aconiti preparata, Semen Cuscutaeand baked ginger, whose main function is invigorating kidney yang and nourishing kidney essence. This prescription has a close relationship with the Han prescription in central plain of China which may be based on certain lost Chinese medical book.

Common effects of fat, ethanol, and nicotine on enkephalin in discrete areas of the brain.

Fat, ethanol, and nicotine share a number of properties, including their ability to reinforce behavior and produce overconsumption. To test whether these substances act similarly on the same neuronal populations in specific brain areas mediating these behaviors, we administered the substances short-term, using the same methods and within the same experiment, and measured their effects, in areas of the hypothalamus (HYPO), amygdala (AMYG), and nucleus accumbens (NAc), on mRNA levels of the opioid peptide, enkephalin (ENK), using in situ hybridization and on c-Fos immunoreactivity (ir) to indicate neuronal activity, using immunofluorescence histochemistry. In addition, we examined for comparison another reinforcing substance, sucrose, and also took measurements of stress-related behaviors and circulating corticosterone (CORT) and triglycerides (TG), to determine if they contribute to these substances' behavioral and physiological effects. Adult Sprague-Dawley rats were gavaged three times daily over 5 days with 3.5 mL of water, Intralipid (20% v/v), ethanol (12% v/v), nicotine (0.01% w/v) or sucrose (22% w/v) (approximately 7 kcal/dose), and tail vein blood was collected for measurements of circulating CORT and TG. On day five, animals were sacrificed, brains removed, and the HYPO, AMYG, and NAc processed for single- or double-labeling of ENK mRNA and c-Fos-ir. Fat, ethanol, and nicotine, but not sucrose, increased the single- and double-labeling of ENK and c-Fos-ir in precisely the same brain areas, the middle parvocellular but not lateral area of the paraventricular nucleus, central but not basolateral nucleus of the AMYG, and core but not shell of the NAc. While having little effect on stress-related behaviors or CORT levels, fat, ethanol, and nicotine all increased circulating levels of TG. These findings suggest that the overconsumption of these three substances and their potential for abuse are mediated by the same populations of ENK-expressing neurons in specific nuclei of the hypothalamus and limbic system.

Protective effect of icariin on kidney in 5/6 nephrectomized rats and its mechanism.

The aim of this study was to investigate the renal protective effect of icariin in 5/6 nephrectomized rats and the molecular mechanisms involved. Forty male Sprague-Dawley rats were randomly divided into 5 groups: sham-operated group, 5/6 nephrectomy model group, icariin groups (20 and 40 mg/kg), and benazepril group. After 12-weeks treatment, 24-h urine and serum were collected, and urine protein, serum creatinine, and blood urea nitrogen were determined. The rats were then sacrificed and fresh kidney tissues were prepared to obtain single cell suspensions. Cell cycle distribution and cell apoptosis were determined by annexin V-FITC/propidium iodide (PI) double staining using a flow cytometer. mRNA expression of Bcl-2 and Bax was examined using quantitative real-time PCR. After 12-weeks treatment, urinary protein, serum creatinine, and blood urea nitrogen in the icariin-treated group were much lower than in the untreated group compared with 5/6 nephrectomy model. Icariin reduced the percentage of S phase cells, increased the percentage of G0/M phase cells, and inhibited apoptosis in the renal cells. mRNA expression of Bcl-2 and Bax was decreased. In conclusion, icariin has a renal protective effect in 5/6 nephrectomized rats, which may be related mainly to alterations in cell cycle distribution and expression of apoptotic genes.

A comparative study on different metal loaded soybean milk by-product 'okara' for biosorption of phosphorus from aqueous solution.

Cationization of agricultural by-products using metal salts is widely used to activate their phosphorous capture ability. This study developed three kinds of new metal loaded soybean milk by-product 'okara' for phosphorus biosorption. A comparative study among these biosorbents was carried out with respect to their performances in terms of affinity, stability and reusability. Zirconium loaded okara (ZLO) was found to have the highest affinity towards PO(4)(3-) anions (47.88 mg/g), followed by iron/zirconium loaded okara--IZLO (40.96 mg/g) and iron loaded okara--ILO (16.39 mg/g). ZLO was successfully desorbed with 0.2M NaOH and activated with 0.1 HCl prior to the next cycle. After five consecutive cycles, the efficiency of both adsorption and desorption of ZLO remained about 85% whilst no Zr(IV) leakage was observed. Conversely, IZLO and ILO suffered from vital short comings such as high metal release and/or sharp reduction in PO4(3-) sequestering capability after multi operation cycles.

Feasibility of iron loaded 'okara' for biosorption of phosphorous in aqueous solutions.

This study investigated the feasibility of using soybean milk by-products (okara) as a sustainable biosorbent for phosphate removal in water and wastewater. The results show that raw okara could hardly decontaminate phosphate from aqueous solutions. Hence, in this work, okara was modified by being cationized using FeCl3 0.25 M (namely iron loaded okara, ILO) to enhance the phosphorus adsorption capacity. The phosphate sorption onto ILO was well achieved under the conditions of pH 3, initial phosphorous concentration of 25 mg/L, biosorbent dose of 20 mg/L and contact time of 7 h. Based on Langmuir model, the maximum adsorption capacity of phosphate by ILO was 4.785 mg/g. The effects of interfering anions were in the order of CO3(2-)>SO4(2-)>NO3(-). It was also observed that Fe(III) was detached during operation. This problem can hinder the sustainable usability of ILO. Thus, further research would be necessary for improving the modification method.

Development of a slow polycolloid-releasing substrate (SPRS) biobarrier to remediate TCE-contaminated aquifers.

In this study, an in situ slow polycolloid-releasing substrate (SPRS) biobarrier system was developed to continuously provide biodegradable substrates for the enhancement of trichloroethylene (TCE) reductive dechlorination. The produced SPRS contained vegetable oil (used as a slow-released substrate), cane molasses [used as an early-stage (fast-degradable) substrate], and surfactants [Simple Green (SG) and soya lecithin (SL)]. An emulsification study was performed to evaluate the globule droplet size and stability of SPRS. The distribution and migration of the SPRS were evaluated in a column experiment, and an anaerobic microcosm study was performed to assess the capability of SPRS to serve as a slow and long-term carbon-releasing substrate for TCE dechlorination. The results show that a stable oil-in-water (W/O, 50/50) emulsion (SPRS) with uniformly small droplets (D10, 0.93 µm) has been produced, continuously supplying primary substrates. The emulsion containing the surfactant mixture (with 72 mg/L SL and 71 mg/L SG) had a small absolute value of the zeta potential, which reduced the inter-particle repulsion, leading the emulsion droplets to adhere to one another after collision. The addition of SPRS creates anaerobic conditions and leads to a more complete and thorough removal of TCE through biodegradation and sorption mechanisms.

Effects of two in-office bleaching agents with different pH on the structure of human enamel: an in situ and in vitro study.

This study evaluated the effects of two in-office bleaching agents (Beyond and Opalescence Boost) with different pH on the structure and mechanical properties of human enamel in vitro and in situ. One hundred and eight enamel slabs were obtained from freshly extracted premolars. The specimens were randomly distributed into nine groups (n=12), and the human saliva (HS) in the volunteers' oral cavities was used to simulate the in situ condition: Beyond + HS, Opalescence Boost (O-Boost) + HS, Control + HS, Beyond + artificial saliva (AS), O-Boost + AS, Control + AS, Beyond + distilled water (DW), O-Boost + DW, and Control + DW. The bleaching treatments were performed on the first and eighth day, and the total bleaching time was 90 minutes. Baseline and final surface roughness (RMS), surface morphology, microhardness, and fracture toughness (FT) were measured before the treatment and on the fifteenth day, respectively. Compared with control groups, surface alterations on enamel were found in the Beyond + AS and Beyond + DW groups under atomic force microscopy evaluation. Two-way analysis of variance and Tukey test revealed that the RMS showed significant intergroup differences for both storage condition and bleaching agent, whereas microhardness and FT revealed no significant alteration. The results indicated that in-office bleaching agents with low pH values could induce enamel morphology alterations under in vitro conditions. The presence of natural HS could eliminate the demineralization effect caused by low pH.

Prenatal ethanol exposure stimulates neurogenesis in hypothalamic and limbic peptide systems: possible mechanism for offspring ethanol overconsumption.

Exposure to ethanol during the prenatal period contributes to increased alcohol consumption and preference in rodents and increased risk for alcoholism in humans. With studies in adult animals showing the orexigenic peptides, enkephalin (ENK), galanin (GAL) and orexin (OX), to stimulate ethanol consumption, the question addressed here is whether prenatal ethanol alters the development in utero of specific neurons that express these peptides. With reports describing suppressive effects of high doses of ethanol, we examined the offspring of dams gavaged from embryonic day 9 to parturition with a control solution or lower ethanol doses, 1 and 3g/kg/day, known to promote ethanol consumption in the offspring. To understand underlying mechanisms, measurements were taken in postnatal offspring of the expression of ENK in the hypothalamic paraventricular nucleus (PVN) and nucleus accumbens (NAc), GAL in the PVN, and OX in the perifornical lateral hypothalamus (PFLH) using real-time qPCR and in situ hybridization, and also of the cell proliferation marker, 5-bromo-2-deoxyuridine (BrdU), and its double-labeling with either neuronal nuclei (NeuN), a marker of mature neurons, or the peptides. On postnatal day 15 (P15), after two weeks without ethanol, the offspring showed increased expression of ENK in the PVN and NAc core but not shell, GAL in the PVN, and OX in the PFLH. In these same areas, prenatal ethanol compared to control increased the density at birth (P0) of neurons expressing these peptides and at P0 and P15 of neurons double-labeling BrdU and NeuN, indicating increased neurogenesis. These BrdU-positive neurons were found to express ENK, GAL and OX, indicating that prenatal ethanol promotes neurogenesis in these specific peptide systems. There were no changes in gliogenesis or apoptosis. This increase in neurogenesis and density of peptide-expressing neurons suggests the involvement of these hypothalamic and accumbal peptide systems in mediating the increased alcohol consumption observed in prenatal ethanol-exposed offspring.

Effect of incremental levels of fish oil supplementation on specific bacterial populations in bovine ruminal fluid.

The objective of this study was to determine the effects of incremental replacement of dietary linoleic acid by >20-carbon polyunsaturated fatty acids (PUFA) on changes in population of ruminal micro-organisms associated with fibre digestion and biohydrogenation using real-time PCR of bacterial 16S rRNA sequences. Four beef steers with ruminal cannulas were randomly assigned to control (CK, 65:35 forage to concentrate), CK with 3% sunflower oil plus 1% fish oil (S3F1), 2.5% sunflower oil plus 1.5% fish oil (S2.5F1.5) or 2% sunflower oil plus 2% fish oil (S2F2) in a 4 × 4 Latin square design with 21-day periods. Ruminal fluid was collected on day 15 of each period. Compared with CK, oil addition led to lower ruminal acetate and butyrate but greater propionate concentration. DNA copy number of Anaerovibrio lipolytica in ruminal fluid was greater with oil (average 5.38 vs. 3.62 × 10(5) DNA copy number), particularly with S2F2 relative to CK. Fibrobacter succinogenes and Butyrivibrio fibrisolvens DNA copy number decreased by 74% (1.06 vs. 4.01 × 10(5)) and 39% (5.16 vs. 8.42 × 10(7)) in response to S2F2 compared with CK. DNA copy numbers of Ruminococcus flavefaciens and Ruminococcus albus were not affected by incremental fish oil. Results suggest that greater availability of PUFA with >20 carbons (i.e. eicosapentaenoic acid and docosahexaenoic acid) promoted changes in bacterial populations that are relevant for fibre digestion and biohydrogenation.

The dentine remineralization activity of a desensitizing bioactive glass-containing toothpaste: an in vitro study.

BACKGROUND: Dentine hypersensitivity occurs easily on exposed dentine. This study aimed to evaluate the effectiveness of a novel bioactive glass-containing toothpaste on dentine permeability and remineralization. METHODS: Thirty dentine discs were divided into three groups of 10 specimens each. The groups corresponded to the following brushing treatments: no brush, distilled water, and bioactive glass-containing toothpaste (Novamin). The toothpaste was applied twice a day for 7 days. Dentine permeability was measured after ethylene-diamine-tetraacetic acid (EDTA) etching, initial application, 3-day application, 7-day application and citric acid challenge, respectively. The dentine morphology was investigated using scanning electron microscopy (SEM). Attenuated total reflection Fourier transform infrared (ATR/FTIR) spectroscopy was performed to monitor the mineral variation on demineralized dentine. Qualitative information of elemental variation before and after treatments on completely demineralized dentine was detected by energy dispersive X-ray (EDX) analysis. RESULTS: The bioactive glass-containing toothpaste significantly reduced dentine permeability after the 7-day treatment and showed, under SEM, excellent resistance to acid challenge compared to the other groups. ATR/FTIR and EDX revealed increased mineral content after treatment with Novamin. CONCLUSIONS: As the innovative bioactive glass-containing toothpaste occlude dentinal tubules and resist acid challenge, it may be useful for the treatment of dentine hypersensitivity and dentine remineralization.

Use of specific gene analysis to assess the effectiveness of surfactant-enhanced trichloroethylene cometabolism.

The objective of this study was to evaluate the effectiveness of in situ bioremediation of trichloroethylene (TCE)-contaminated groundwater using specific gene analyses under the following conditions: (1) pretreatment with biodegradable surfactants [Simple Green™ (SG) and soya lecithin (SL)] to enhance TCE desorption and dissolution, and (2) supplementation with SG, SL, and cane molasses as primary substrates to enhance the aerobic cometabolism of TCE. Polymerase chain reaction (PCR), denaturing gradient gel electrophoresis (DGGE), and nucleotide sequence analysis were applied to monitor the variations in specific activity-dependent enzymes and dominant microorganisms. Results show that TCE-degrading enzymes, including toluene monooxygenase, toluene dioxygenase, and phenol monooxygenase, were identified from sediment samples collected from a TCE-spill site. Results from the microcosm study show that addition of SG, SL, or cane molasses can enhance the aerobic cometabolism of TCE. The TCE degradation rates were highest in microcosms with added SL, the second highest in microcosms containing SG, and lowest in microcosms containing cane molasses. This indicates that SG and SL can serve as TCE dissolution agents and act as primary substrates for indigenous microorganisms. Four dominant microorganisms (Rhodobacter sp., Methyloversatilis sp., Beta proteobacterium sp., and Hydrogenophaga pseudoflava) observed in microcosms might be able to produce TCE-degrading enzymes for TCE cometabolic processes.

In situ oxidation of petroleum-hydrocarbon contaminated groundwater using passive ISCO system.

Groundwater contamination by gasoline spill is a worldwide environmental problem. Gasoline contains methyl tertiary-butyl ether (MTBE) (a fuel oxygenates) and benzene, which are the chemicals of concerns among the gasoline components. In this study, an in situ chemical oxidation (ISCO) barrier system was developed to evaluate the feasibility of applying this passive system on the control of MTBE and benzene plume in aquifer. The developed ISCO barrier contained oxidant-releasing materials, which could release oxidants (e.g., persulfate) when contact with water for the contaminants' oxidation in groundwater. In this study, laboratory-scale fill-and-draw experiments were conducted to determine the component ratios of the oxidant-releasing materials and evaluate the persulfate release rates. Results indicate that the average persulfate-releasing rate of 7.26 mg S(2)O(8)(2-)/d/g was obtained when the mass ratio of sodium persulfate/cement/sand/water was 1/1.4/0.24/0.7. The column study was conducted to evaluate the efficiency of in situ application of the developed ISCO barrier system on MTBE and benzene oxidation. Results from the column study indicate that approximately 86-92% of MTBE and 95-99% of benzene could be removed during the early persulfate-releasing stage (before 48 pore volumes of groundwater pumping). The removal efficiencies for MTBE and benzene dropped to approximately 40-56% and 85-93%, respectively, during the latter part of the releasing period due to the decreased persulfate-releasing rate. Results reveal that acetone, byproduct of MTBE, was observed and then further oxidized completely. Results suggest that the addition of ferrous ion would activate the persulfate oxidation. However, excess ferrous ion would compete with organic contaminants for persulfate, and thus, cause the decrease in contaminant oxidation rates. The proposed treatment scheme would be expected to provide a more cost-effective alternative to remediate MTBE, benzene, and other petroleum-hydrocarbon contaminated aquifers. Results from this study will be useful in designing a scale-up system for field application.

Production and synthetic dyes decolourization capacity of a recombinant laccase from Pichia pastoris.

AIMS: To produce and purify a recombinant laccase from Pichia pastoris and to test its ability in decolourization of synthetic dyes. METHODS AND RESULTS: A cDNA encoding for a laccase was isolated from Pycnoporus sanguineus and was expressed in P. pastoris strain SMD1168H under the control of the alcohol oxidase (AOX1) promoter. The laccase native signal peptide efficiently directed the secretion of the recombinant laccase in an active form. Factors influencing laccase expression, such as cultivation temperature, pH, copper concentration and methanol concentration, were investigated. The recombinant enzyme was purified to electrophoretic homogeneity, and was estimated to have a molecular mass of about 62.8 kDa. The purified enzyme showed a similar behaviour to the native laccase produced by P. sanguineus. Four different synthetic dyes including azo, anthraquinone, triphenylmethane and indigo dyes could be efficiently decolourized by the purified recombinant laccase without the addition of redox mediators. CONCLUSIONS: Heterologous production of P. sanguineus laccase in P. pastoris was successfully achieved. The purified recombinant laccase could efficiently decolourize synthetic dyes in the absence of mediators. SIGNIFICANCE AND IMPACT OF THE STUDY: This study is the first report on the synthetic dye decolourization by the recombinant P. sanguineus laccase. The decolourization capacity of this recombinant enzyme suggested that it could be a useful biocatalyst for the treatment of dye-containing effluents.