[Experimental study on the therapeutic effect and mechanism of erlotinib on non-proliferative diabetic retinopathy]

Objective: To investigate the therapeutic effect and mechanism of erlotinib, an epidermal growth factor receptor (EGFR) inhibitor, on non-proliferative diabetic retinopathy (NPDR). Methods: An experimental research was conducted. Human retinal Müller cells (RMC) were MIO-M1 cells from Moorfields Ophthalmology Hospital and the Institute of Ophthalmology at London University College. MIO-M1 cells were divided into normal, hypertonic, high glucose, high glucose+dimethyl sulfoxide (DMSO), high glucose+erlotinib 0.5 mmol/L, high glucose+erlotinib 1 mmol/L, and high glucose+erlotinib 2 mmol/L groups using a random number table method. Detection of the effect of erlotinib on the proliferation of MIO-M1 cells under high glucose conditions was performed by 5-ethynyl-2'-deoxyuridine (EdU) method. Western blotting (WB) was used to detect the effect of erlotinib on the activation markers of glial fibrillary acidic protein (GFAP) and glutamine synthetase (GS) protein levels in MIO-M1 cells under high glucose conditions. WB was used to detect the effect of erlotinib on the protein levels of nerve growth factor receptor (p75NTR), vimentin, and cell retinol binding protein (CRALBP) in RMC under high glucose conditions. MIO-M1 cells were divided into normal group, high glucose group, high glucose+DMSO group, and high glucose+erlotinib (1 mmol/L) group using random number table method. The effect of erlotinib on EGFR nuclear translocation under high glucose conditions was detected by cell immunofluorescence staining. Immunoprecipitation was used to detect the effect of erlotinib on the interaction between EGFR and transcription intermediate factor 2 (TIF2) in MIO-M1 cells under high glucose conditions. MIO-M1 cells were randomly divided into normal group, high glucose group, high glucose+DMSO group, high glucose+Myc-DDK empty body group, high glucose+erlotinib group, high glucose+erlotinib+human doublet protein group, high glucose+erlotinib+TIF2 plasmid group, and high glucose+erlotinib+human doublet protein+TIF2 plasmid group. Cell immunofluorescence staining was used to detect the effect of erlotinib on the binding of EGFR and TIF2 in MIO-M1 cells under high glucose conditions through the EGFR/TIF2 axis. Quantitative reverse transcription polymerase chain reaction (qRT-PCR) was used to detect the regulatory effect of EGFR and TIF2 binding on cyclin D1 transcription in MIO-M1 cells under high glucose conditions. The mouse model of diabetes retinopathy (DR) was constructed and divided into normal group, DR group, DR+DMSO group, DR+erlotinib 0.25 mg·kg-1·d-1 group, DR+erlotinib 0.5 mg·kg-1·d-1 group and DR+erlotinib 1 mg·kg-1·d-1 group. 25 mice in total, 5 in each group. Tissue immunofluorescence staining was used to detect the expression of RMC activation marker GFAP. The FITC-dextran injection experiment was used to detect the effect of erlotinib on retinal vascular leakage in a murine DR model. Results: Compared with the normal group (32.4%±3.0%), the proportion of EdU positive cells in RMC in the high glucose group (59.2%±3.8%) increased (P<0.001). Compared with the high glucose group (59.2%±3.8%), the proportion of EdU positive cells in the high glucose+1 mmol/L erlotinib group (37.6%±4.4%) decreased (P<0.001). Compared with the normal group, the expression of GFAP in RMC in the high glucose group increased (1 in the normal group, 2.27±0.11 in the high glucose group, P<0.001), while the expression of GS decreased (1 in the normal group, 0.32±0.03 in the high glucose group, P<0.001). 1 mmol/L erlotinib treatment reduced the expression of GFAP in RMC under high glucose conditions (1.32±0.13 and 2.27±0.11, respectively; P<0.001), and increased the expression of GS (0.71±0.06 and 0.32±0.03, respectively; P<0.001). The colocalization of EGFR and DAPI in RMC of the high glucose+1 mmol/L erlotinib group was lower than that of the high glucose group (52.2%±4.1% and 76.4%±5.7%, respectively; P<0.001). The expression of TIF2 or EGFR both increased while using EGF or TIF2 antibodies to precipitate TIF2 or EGFR under high glucose conditions compared to the normal group (1 in the normal group, 2.27±0.20 in the high glucose group, 2.17±0.21 in the EGFR, all P<0.05). And the expression of TIF2 (1.38±0.10) or EGFR (1.32±0.13) in the high glucose+erlotinib group was lower than that in the high glucose group (2.27±0.20) and the high glucose group (2.17±0.21) (all P<0.05). The colocalization of EGFR and TIF2 (17.2%±3.9%) and the mRNA level of Cyclin D1 (1.32±0.16) in the RMC of the high glucose+erlotinib group were lower than those in the high glucose group (54.6%±3.7% of EGFR and TIF2 colocalization ratio, 2.58±0.19 of Cyclin D1 mRNA level,all P<0.05). The high glucose+erlotinib+AREG (EGFR agonist) group, high glucose+erlotinib+Myc DDK-TIF2 plasmid group and high sugar+erlotinib+AREG+Myc-DDK-TIF2 plasmid group EGFR colocalization with TIF2 (colocalization ratios 24.1%±1.9%, 26.0%±2.3%, 35.3%±2.5%) and TIF2 mRNA levels (1.71±0.16, 1.72±0.18, 2.20±0.18). Compared with the high glucose+erlotinib group, The increases were statistically significant (all P<0.05). Compared to the normal group, the expression of GFAP in mouse retina tissue was increased in the DR group (1 in the normal group, 3.07±0.19 in the DR group, P<0.001), and 0.5 mg·kg-1·d-1 erlotinib (1.73±0.30) significantly reduced the expression of GFAP in the retina of DR group mice (P<0.05). Compared to the normal group (3.97±0.47), the DR group (23.13±2.15) showed an increase in fluorescein leakage, while the DR+erlotinib group (11.66±1.45) showed a significant decrease in leakage compared to the DR group (all P<0.05). Conclusions: Erlotinib inhibits the proliferation and activation of RMC induced by high glucose, inhibits the entry of EGFR into the nucleus, inhibits the binding of EGFR to TIF2 in RMC, and reduces the transcription of Cyclin D1 in RMC by inhibiting the interaction between EGFR and TIF2. At the same time, erlotinib inhibits the proliferation and activation of RMC in the mouse DR model, ameliorating retinal vascular leakage in mice. These results suggest that erlotinib inhibits the activation and proliferation of RMC by downregulating the EGFR/TIF2/Cyclin D1 pathway under high glucose conditions, thereby alleviating the progression of NPDR.

Hemoglobin within normal range is negatively related to hemoglobin A1c in a nondiabetic American population aged 16 years and older

BACKGROUND

Protein glycosylated hemoglobin, hemoglobin A1c (HbA1c) binds hemoglobin (Hb) in red blood cells to blood glucose. However, the relationship between Hb and HbA1c remains unclear.

AIM

To elucidate their relationship in a nondiabetic population aged ≥ 16 years in the United States, using data from the 1999-2018 National Health and Nutrition Examination Survey.

METHODS

This study was based on data from 44560 adults aged ≥ 16 years, excluding those with diabetes. The relationship was estimated using a multivariate regression. We also used piecewise linear regression for subgroup analysis based on age and sex stratification and analysis of the threshold effects of Hb on HbA1c.

RESULTS

Hb and HbA1c levels were negatively correlated in the unadjusted model (β = -0.01; 95%CI: -0.01, -0.01). The correlation was significantly negative when the regression model was minimally regulated and stratified by age and sex, and remained negative when the model was further regulated (more than 10%) to identify covariates with the HbA1c level influence estimates. In subgroup analyses based on age and sex stratification, the association remained negative when the covariates were controlled. A nonlinear relationship was observed between them when the Hb levels reached the tipping point (13.2 g/dL) (adjusted odds ratio, -0.04; 95%CI: -0.05, -0.03) and when the Hb levels exceeded 13.2 g/dL (adjusted odds ratio, -0.10; 95%CI: -0.10, -0.09).

CONCLUSION

Our study shows that normal Hb levels are negatively correlated with HbA1c in nondiabetic Americans aged ≥ 16 years.

Comparative analysis of the quantitative parameter method and elasticity color mode method for real-time shear wave elastography in the diagnosis of benign and malignant solid breast lesions

OBJECTIVE

To examine the performance of real-time shear wave elastography (RT-SWE) in routine clinical practice.

METHODS

This was a prospective study of 500 patients. The elasticity color mode method was judged by a four-mode system. The quantitative parameter method was used to measure the modulus of elasticity of the lesions. Pathologic reports were used as a gold standard to comparatively analyze the diagnostic performance of the two methods.

RESULTS

A total of 553 tumors were detected. The average mode value and the modulus of elasticity (E_max) of the benign breast masses was lower than that of malignant masses (p < 0.05). With E_max = 67.4 as the diagnostic threshold value, the sensitivity, specificity, accuracy, negative predictive value, and positive predictive value of the two methods were not statistically significant different (p > 0.05).

CONCLUSIONS

The shear wave quantitative parameter method and the elasticity color mode method showed similar performances in the diagnosis of benign and malignant breast masses. The elasticity color mode method is convenient and intuitive, whereas the quantitative parameter method can be used to objectively assess the lesions when it is difficult to score the elasticity of an image, but could not be relied on alone.

Mixotrophic cultivation of microalgae coupled with anaerobic hydrolysis for sustainable treatment of municipal wastewater in a hybrid system of anaerobic membrane bioreactor and membrane photobioreactor

This study investigated the possibility of coupling anaerobic hydrolysis in an anaerobic membrane bioreactor (AnMBR) with mixotrophic microalgae cultivation in a membrane photobioreactor (MPBR) for the sustainable treatment of municipal wastewater. Using the hydrolyzed wastewater discharged from AnMBR, Chlorella pyrenoidosa in MPBR grew in a mixotrophic mode and realized rapid growth. During the stable operation, MPBR achieved average carbon capture rate of 42.82 mg L^-1 d^-1 and algal lipid production rate of 19.66 mg L^-1 d^-1. The average reduction in TN, TP, and TOC during stable operation was 96.7%, 98.0%, and 95.9%, respectively. Mass balance analysis showed that the overall system captured 14.76 mg of carbon from the atmosphere per liter of wastewater treated. Therefore, this AnMBR-MPBR hybrid system simultaneously realized advanced treatment of municipal wastewater, efficient production of algal lipid, and carbon capture from atmosphere, and thus has a good potential in the sustainable treatment of municipal wastewater.

[The association between apparent temperature and hand, foot, and mouth disease and its spatial heterogeneity in Guangdong, Anhui and Jilin provinces]

Objective: To study the association between apparent temperature (AT) and the incidence of hand,foot, and mouth disease (HFMD) and its spatial heterogeneity in 46 cities in Guangdong, Anhui and Jilin provinces, and provide scientific evidence for the early warning of HFMD. Methods: The data of HFMD incidence and meteorological factors from 2009 to 2018 in Guangdong province, 2009 to 2015 in Anhui province, and 2013 to 2018 in Jilin province were collected. Distributed lag non-linear models were constructed to investigate the association between AT and the incidence of HFMD in 46 cities from three provinces in China. Meta-analysis was used to pool the city-specific estimates, and Meta-regression was applied to analyze the factors that may cause spatial heterogeneity. Results: The relationship between daily AT and the incidence of HFMD in 46 cities appeared nonlinear. The association in Guangdong was similar to that in Jilin, and the risk of HFMD increased with the increase of AT. While the risk of HFMD in Anhui first increased with the increase of AT, and peaked at 18.1 ℃ and then went down. AT on different levels showed different lag impacts and the higher AT showed greater and longer lag impact. The spatial heterogeneity of associations may have been caused by latitude, longitude, average temperature, and average sunshine hours. Conclusions: AT is a comprehensive index to evaluate the association between temperature, relative humidity and wind speed and the incidence of HFMD. Higher AT may increase the risk of HFMD. The AT and HFMD relationship across spatial heterogeneity varies depending on geographic location and meteorological conditions.

A 14-amino acids deletion in BmShadow results to non-moult on the 2nd instar in the bivoltine silkworm, Bombyx mori

The Bombyx mori Shadow gene (BmShadow) belongs to the superfamily of cytochrome P450 genes. To elucidate the function of the BmShadow gene and its association with diapause, we employed the CRISPR/Cas9 system to knock out the BmShadow gene in the bivoltine strain Qiufeng. The mutant (BmShadow^-/-) was obtained in G₂, exhibiting a 42-base deletion corresponded exactly to the amino acids regions from positions 155 to 168. The larvae of BmShadow^-/- cannot moult at the pre-moulting stage of the 2nd instar. When the BmShadow^-/- larvae were fed with 20E analogue at the late stage of the 2nd instar, they were rescued and developed into the 3rd instar. Rescue experiments indicated that the 20E concentration of BmShadow^-/- larvae was significantly lower than that in WT larvae, and the 20E concentration of BmShadow^-/- larvae which fed 20E analogue was restored to normal levels. Interestingly, the BmShadow^-/- larvae could not moult on the 1st instar when they hatched from eggs after being stored at 5 °C for 40 days or after hibernation, suggesting that the 20E transported from the mother was partially consumed in the diapause maintenance phase. Our study confirmed that BmShadow is involved in 20E synthesis and a 14-amino acids region from position 155 to 168 was essential for its function, also there appears to be no other compensation pathway in vivo, which offered an important potential target locus for the control of silkworm development and the biological control of agricultural and forestry pests.

[The expression of long non-coding RNA LINC00261 in laryngeal carcinoma tissue and their clinical significance]

Objective:To investigate the expression of LINC00261 in laryngeal carcinoma and to discuss their relevance and the roles in carcinogenesis and development of laryngeal carcinoma. Method:The expressions of LINC00261 in laryngeal carcinoma tissue and paired adjacent normal tissue was determined by real-time PCR. The relationship between the expressions of LINC00261 and the clinic pathological characteristics including clinical stage, pathological type, histological grade and lymph node metastasis in LSCC was analysed according to the clinical data. Result:①The expression of LINC00261 was significantly decreased in the LSCC tissue compared with the normal laryngeal tissue(P<0.01).②In clinical stage grouping, there were no statistical differences of the quantity of LINC00261 expression among supraglottic, glottic and subglottic LSCC(P>0.05).In histological differentiation grouping, LINC00261 had no significant changes in poorly differentiated LSCC compared with the well and moderately differentiated LSCC(P>0.05). In histological grade grouping, the expression of LINC00261 in T1+T2 stages was significantly higher than T3+T4 stages(P<0.05). Moreover, the expression of LINC00261 in LSCC with lymph node metastasis was significantly lower than that without of lymph node metastasis(P<0.05). Conclusion:Down regulation of LINC00261 in laryngeal carcinoma may contribute to the carcinogenesis and development of laryngeal carcinoma. The decreased expression of LINC00261 maybe relative to T term degree and lymphamatic metastasis of laryngeal carcinoma.

[Expression of signaling pathway of mammalian target of rapamycin in articular cartilage cell induced by interleukin 1β]

Objective: To observe effect of interleukin(IL)-1β on the expression of signaling pathway of mammalian target of rapamycin(mTOR) of articular cartilage. Methods: Articular cartilage of rats was isolated under sterile technique, cells were digested by type Ⅱ collagenase and trypsin and cultured in vitro, pre-culture the Ⅱ cells for three days, different concentrations of IL-1β were added for 24 hours.The cells were stained with toluidine blue and HE, to observe morphological changes of cells.RT-PCR was used to detect the mRNA expression of typeⅡcollagen gene, aggrecan gene, mTOR gene and P70S6K gene, Western blotting was used to detect the expression of protein related to mTOR. Results: With increasing concentrations of IL-1β, the phenotype of cells appeared polygon into a spindle, the mRNA expression of gene of type Ⅱ collagen (the control group: 0.821±0.014; 1 ng/ml: 0.614±0.014; 10 ng/ml: 0.549±0.009; 100 ng/ml: 0.520±0.008), aggrecan(0.867±0.005; 0.857±0.001; 0.554±0.008; 0.538±0.004) and mTOR(0.845±0.015; 0.785±0.009; 0.569±0.025; 0.518±0.014) reduced, but P70S6K(0.465±0.024; 0.566±0.022; 0.663±0.022; 0.896±0.015) increased by PCR .Expression of protein detected by Western blotting was similar to the trend of PCR. Conclusion: mTOR signaling pathway may play an important role on the degeneration of articular cartilage, regulating mTOR signaling pathway may provides a new idea of delaying the degeneration process of cells.

Synthesis of polymethylene-b-poly(vinyl acetate) block copolymer via visible light induced radical polymerization and its application

Polymethylene-b-poly(vinyl acetate) block copolymers were synthesized by polyhomologation of ylides and visible light-induced degenerative iodine transfer polymerization of vinyl acetate.

[Expression of Has-miR-93-5p in laryngeal squamous cell carcinoma and its clinical significance]

Objective:To investigate the expression of has-miR-93-5p on human laryngeal squamous cell carcinoma and the influence on malignant phenotype of Hep-2 cell.Method:The expression of has-miR-93-5p of paraffin samples in LSCC was determined by looped-primer Real-time PCR, and the relationship between the expression and the clinical pathological parameters was analysed. The has-miR-93-5p Inhibitor sequence was transfected into Hep-2 cells as the Inhibitor group. Using the MTS assay, Edu and colony formation assay to investigate the change of cell viability,proliferation and clone formation ability after transfection. Transwell invasion assay was used to detect the changes of cell migration and invasion ability. Flow cytometry was used to detect the changes of cell cycle and apoptosis.Result:The relative expression of has-miR-93-5p in LSCC was 11.148±1.141,which was higher than in normal tissues of adjacent to carcinoma1(985±4.547)（P <0.01）.The constituent ratio of has-miR-93-5p high expression in the group of low differentiation, T3+T4 and lymphatic metastasis was 69.8%、76.5%and 89.5%,which was higher than the group of high differentiation,T1+T2 and nonlymphatic metastasis respectively（P <0.05）, Inhibition the expression of has-miR-93-5p in vitro in Hep-2 cells could obviously inhibit the cell vitality, proliferation, clone, migration, and invasion ability, also could retardant the cells in G2/M phase, and promote its apoptosis.Conclusion: has-miR-93-5p might be an important molecule in pathogenesis of laryngeal squamous cell carcinoma. It could inhibit malignant phenotype of laryngeal squamous cancer cells when has-miR-93-5p expressionwas suppressed in vitro.

Positive association between PPARD rs2016520 polymorphism and coronary heart disease in a Han Chinese population

PPARD encodes peroxisome proliferator-activated re-ceptor delta, which has been shown to play an important role in control-ling lipid metabolism and atherosclerosis. In this case-control study, we explored the relationship between PPARD rs2016520 polymorphism and coronary heart disease (CHD) in a Han Chinese population. A to-tal of 657 CHD cases and 640 controls were included in the associa-tion study. rs2016520 polymorphism genotyping was performed using the melting temperature-shift polymerase chain reaction method. The PPARD rs2016520-G allele reduced CHD risk by 17.9% (χ(2) = 5.061, P = 0.025, OR = 0.821, 95%CI = 0.692-0.975). Furthermore, a signifi-cant difference in CHD risk was observed for the PPARD rs2016520 polymorphism in the dominant model (AG + GG vs AA: χ(2) = 4.751, degrees of freedom (df) = 1, P = 0.029, OR = 0.784, 95%CI = 0.631- 0.976). Analysis by age suggested that the G-allele decreased CHD risk by 14.8% in ages greater than 65 years (χ(2) = 4.446, P = 0.035, OR = 0.852, 95%CI = 0.684-1.060). In contrast, meta-analysis of PPARD rs2016520 among 3732 cases and 5042 controls revealed no associa-tion between PPARD rs2016520 and CHD (P = 0.19). We found that the PPARD rs2016520-GG genotype decreased CHD risk in a Han Chinese population. Moreover, we found an association between serum high-density lipoprotein cholesterol level and PPARD rs2016520 in senior individuals aged ≥ 65 years. The meta-analysis revealed no association between PPARD rs2016520 and CHD, suggesting ethnic differences in the association between the PPARD locus and CHD.

Synthesis of diverse α,ω-telechelic polystyrenes with di- and tri-functionality via tandem or one-pot strategies combining aminolysis of RAFT-polystyrene and a thiol–ene “click” reaction

Diverse new α,ω-telechelic polystyrenes with di-/tri-functionality were synthesized via tandem/one-pot strategies combining aminolysis of RAFT-polystyrene and a thiol–ene “click” reaction.

Synthesis of well-defined α-fluorinated alkyl ester, ω-carboxyltelechelic polystyrenes and fabrication of their hydrophobic highly ordered porous films and microspheres

Porous films and microspheres of α-fluorinated alkyl ester, ω-carboxyl telechelic polystyrenes synthesized via combining aminolysis of RAFT-polystyrene with thiol–ene “click” reaction.

Highly thermally stable hydrogels derived from monolayered two-dimensional supramolecular polymers

Hydrogels have been constructed from monolayered two-dimensional (2D) supramolecular polymers in water. The as-prepared hydrogels exhibited extremely high thermal stabilities, which demonstrates how the 2D structure can impact the bulk properties of soft materials.

New polymethylene-based AB2 star copolymers synthesized via a combination of polyhomologation of ylides and atom transfer radical polymerization

Polymethylene-based AB₂ star copolymers were synthesized. PM-b-(PS)₂ porous films and particles were fabricated via static breath-figure process and electrospraying, respectively.

Differentially expressed genes in the ovary of the sixth day of pupal "Ming" lethal egg mutant of silkworm, Bombyx mori

The "Ming" lethal egg mutant (l-em) is a vitelline membrane mutant in silkworm, Bombyx mori. The eggs laid by the l-em mutant lose water, ultimately causing death within an hour. Previous studies have shown that the deletion of BmEP80 is responsible for the l-em mutation in silkworm, B. mori. In the current study, digital gene expression (DGE) was performed to investigate the difference of gene expression in ovaries between wild type and l-em mutant on the sixth day of the pupal stage to obtain a global view of gene expression profiles using the ovaries of three l-em mutants and three wild types. The results showed a total of 3,463,495 and 3,607,936 clean tags in the wild type and the l-em mutant libraries, respectively. Compared with those of wild type, 239 differentially expressed genes were detected in the l-em mutant, wherein 181 genes are up-regulated and 58 genes are down-regulated in the mutant strain. The Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis results showed that no pathway was significantly enriched and three pathways are tightly related to protein synthesis among the five leading pathways. Moreover, the expression profiles of eight important differentially expressed genes related to oogenesis changed. These results provide a comprehensive gene expression analysis of oogenesis and vitellogenesis in B. mori which facilitates understanding of both the specific molecular mechanism of the 1-em mutant and Lepidopteran oogenesis in general.

Changes in quantity and spectroscopic properties of water-extractable organic matter during soil aquifer treatment

The aim of this study was to identify qualitative and quantitative changes in the character of water-extractable organic matter (WEOM) in soils as a consequence of soil aquifer treatment (SAT). Soil samples were obtained from a soil-column system with a 2-year operation, and divided into seven layers from top to bottom: CS1 (0-12.5 cm), CS2 (12.5-25 cm), CS3 (25-50 cm), CS4 (50-75 cm), CS5 (75-100 cm), CS6 (100-125 cm) and CS7 (125-150 cm). A sample of the original soil used to pack the columns was also analysed to determine the effects of SAT. Following 2 years of SAT operation, both soil organic carbon and water-extractable organic carbon were shown to accumulate in the top soil layer (0-12.5 cm), and to decrease in soil layers deeper than 12.5 cm. The WEOM in the top soil layer was characterized by low aromaticity index (AI), low emission humification index (HIX) and low fluorescence efficiency index (F(eff)). On the other hand, the WEOM in soil layers deeper than 12.5 cm had increased values of HIX and F(eff), as well as decreased AI values relative to the original soil before SAT. In all soil layers, the percentage of hydrophobic and transphilic fractions decreased, while that of the hydrophilic fraction increased, as a result of SAT. The production of the amide-2 functional groups was observed in the top soil layer. SAT operation also led to the enrichment of hydrocarbon and amide-1 functional groups, as well as the depletion of oxygen-containing functional groups in soil layers deeper than 12.5 cm.

Effect of ultrasonic and alkaline pretreatment on sludge degradation and electricity generation by microbial fuel cell

Both ultrasonic and alkaline pretreatment of excess sewage sludge were investigated to enhance organic degradation and electricity generation from sludge by the subsequent microbial fuel cell (MFC). The ultrasonic pretreatment showed that the degree of sludge disintegration was directly related to the energy input, ultrasonic density and duration. Alkaline pretreatment demonstrated that more soluble organic matters were released from the sludge with more NaOH dose and longer reaction time, and the degree of sludge disintegration within 30 min accounted for 45-76% of that for 24 h. When ultrasonic and alkaline pretreatment were combined, the released chemical oxygen demand (COD) was higher than those with ultrasonic or alkaline pretreatment alone. Ultrasonic and alkaline (pH=11) pretreatment could enhance electricity generation from sludge by the subsequent MFC, resulting in more degradation of total COD (TCOD) and volatile solids (VS). Slight change in power output from the MFC was observed due to the higher soluble chemical oxygen demand (SCOD) in the pretreated sludge. By using the combined ultrasonic and alkaline pretreatment of sludge, the removal efficiencies of TCOD and VS were increased from 27.1% to 61.0% and 35.2% to 62.9% in comparison with raw sludge, respectively, and the power output in MFC was slightly increased from 10.3 W/m(3) to 12.5 W/m(3).

Transformation of nitrogen and distribution of nitrogen-related bacteria in a polluted urban stream

Most researchers focused on either nitrogen species or microbial community for polluted urban stream while ignoring the interaction between them and its effect on nitrogen transformation, which restricted the rational selection of an effective and feasible remediation technology. Taking Buji stream in Shenzhen (China) as target stream, the distribution of nitrogen-related bacteria was investigated by most probable number (MPN) besides analysis of nitrogen species etc. The nitrogen-related bacteria in sediment were 10(2) times richer than those in water. Owing to their faster growth, the MPN of ammonifying bacteria and denitrifying bacteria were 10(5) and 10(2) times higher than those of nitrifying bacteria, respectively. The ammonifying bacteria numbers were significantly related to BOD5 in water, while nitrifying bacteria in sediment correlated well with nitrate in water. Thus, nitrification occurred mainly in sediment surface and was limited by low proportion of nitrifying bacteria. The denitrifying bacteria in sediment had good relationship with BOD5 and nitrite and nitrate in water. Low DO and rich organic compounds were beneficial to denitrification but unfavourable to nitrification. Denitrification was restricted by low nitrite and nitrate concentration. These results could be served as a reference for implementing the remediation scheme of nitrogen polluted urban stream.

Characterization of CIb1 gene promoter from silkworm, Bombyx mori

The hemolymph chymotrypsin inhibitor b1 (CIb1) of silkworm, Bombyx mori, plays an important role in innate immunity. In order to study its encoding gene CIb1, five heterogeneous promoter fragments of 844 bp, 682 bp, 516 bp, 312 bp and 82 bp in length were cloned from genomic DNA of the p50 silkworm strain. Characterization of the CIb1 promoter was performed in vitro using the firefly luciferase gene as reporter. The results showed that CIb1 promoter fragments have transcription activities in the B. mori ovary-derived BmN cell line. The 82 bp fragment (-72 to +10 nt) containing the eukaryotic core promoter elements revealed a basic transcription activity. The Bm1 element, upstream the transcription initiation site, showed a positive regulation function to the CIb1 promoter. CIb1 promoter-like fragments from the genomic DNA of the tetra hybrid silkworm SujuxMinghu provided a natural deletion model for the study of the CIb1 promoter. In vitro analysis indicated that the 132 bp fragment from -517 nt to -386 nt upstream of the transcription initiation site strongly suppressed the transcription activity of the CIb1 promoter, suggesting that the 132 bp fragment harbours strong negative cis-acting elements. Infection of Bombyx mori nucleopolyhedrovirus (BmNPV) increased the activity of the CIb1 promoter, having provided another evidence to the function of CIb1 in the innate immunity of silkworm.

Continuous electricity production from leachate in a novel upflow air-cathode membrane-free microbial fuel cell

In this study, a novel microbial fuel cell, i.e. upflow air-cathode membrane-free microbial fuel cell (UAMMFC) was reported and its performance in electricity generation from original leachate was examined. The experimental results demonstrated that the UAMMFC could continuously generate electricity from leachate (0.3V; REX=150 Omega) for an operational period of time (50 h). The maximum volumetric power reached 12.8 W/m3 at current density of 41 A/m3 (93 Omega). NH4+-N elimination from the leachate was shown to be a consequence of electrochemistry-independent oxidation occurred in the MFC. Increasing organic loading rate from 0.65 to 5.2 kgCOD/m3 d resulted in a decrease of overall Coulombic efficiency (CE) from 14.4% to 1.2%. The low CE obtained here should be attributed to severe oxygen diffusion from the open-to-air cathode.

Oral immunization with a live recombinant attenuated Salmonella typhimurium protects mice against Toxoplasma gondii

The natural site of infection for T. gondii is the mucosal surface of the intestine, so the protective immunity obtained after natural infection with T. gondii points to the importance of developing a vaccine that stimulates mucosal defences. In this study, an aroA- and aroD- attenuated strain of Salmonella typhimurium (BRD509) has been used to deliver the recombinant eukaryotic plasmid pSAG(1-2)/CTA2/B expressing a multi-antigenic gene encoding SAG1 and SAG2 of T. gondii linked to A2/B subunits of cholera toxin as a candidate oral T. gondii vaccine. Immunoblot analysis showed compound gene expression in HeLa cells in vitro and intragastric immunization of mice with the recombinant salmonella resulted in the induction of humoral and Th1 type cellular immune responses and afforded protection against RH strain T. gondii challenge. Anti-T. gondii IgG values increased markedly in the BRD509/pSAG(1-2)-CTA2/B immunized group; these values were significantly higher than those in the negative controls (P = 0.008). With CTA2/B genetic adjuvant, the T. gondii-specific response was predominantly Th1, indicating that the CTA(2)/B genetic adjuvant was able to overcome the strong Th2-bias of the antigen (IgG2a >> IgG1). Antigen-specific T cell proliferative responses and CTL activity were significantly enhanced when cholera toxin CTA2/B genetic adjuvant was used (P = 0.009; P = 0.006). Culture supernatants from antigen-stimulated splenocytes from mice in these groups were also examined by ELISA for Th1- and Th2-type cytokines; mean IFN-gamma levels produced after oral immunization with BRD509/pSAG(1-2)-CTA2/B were about nine-fold higher than after immunization with BRD509/pSAG(1-2) (P = 0.007). On the other hand, the levels of IL-4 were low for all groups and no increase was seen in the presence of CTA2/B genetic adjuvant. When the immunized mice were intraperitoneally challenged with 10(3) tachyzoites of the highly virulent RH strain, the survival time of the mice immunized with BRD509/pSAG(1-2)-CTA2/B was markedly longer than other groups (P = 0.003) and a 40% survival rate was achieved. This is the first report that demonstrates that an oral attenuated salmonella DNA vaccine can induce protective immunity against the acute phase of T. gondii infection.

MAP precipitation from landfill leachate and seawater bittern waste

The leachates generated at Hong Kong landfill sites contain high strength of ammonium-nitrogen (NH4+-N) over 3,000 mg l(-1) and are generally inhibitive to most biological treatment processes. To remove the NH4+-N from the landfill leachates and also recover the nitrogen as a struvite fertilizer, a lab-scale study was performed to investigate the feasibility of NH4+-N removal and struvite crystallization using different magnesium sources. Three combinations of chemicals, MgCl2 x 6H2O+Na2HPO4 x 12H2O, MgO+H3PO4 and MgSO4 x 7H2O+Ca(H2PO4) x H2O, were first used at different molar ratios to precipitate NH4+-N from the leachate. The experimental results indicated that NH4+-N was removed by 92%, 36% and 70% respectively at pH 9.0 and a molar ratio of Mg:N:P=1:1:1. Two synthetic seawater bitten wastes containing Mg2+ at 9,220 mg l(-1) and 24,900 mg l(-1) respectively were then used as a magnesium source, while 85% H3PO4 chemical was used as a phosphorus source. The results revealed that NH4+-N was removed by 80% and 72% respectively, while a molar ratio of Mg:N:P=1:1:1 was applied. In the final stage of experiments, the magnesium-ammonium-phosphate (MAP) precipitates were examined by SEM, EDS and XRD. The SEM micrographs of the MAP precipitates showed a typical morphology of elongated tubular and short prismatic crystals. The EDS and XRD results indicated that the chemical composition of the MAP precipitates depended on the chemicals used and experimental conditions. The study confirmed that the recovery of NH4+-N from landfill leachate and seawater bitten wastes could be effectively achieved by MAP precipitation to obtain struvite crystals with a composition of 5.1%N, 10.3%Mg and 16.5%P.

Enhancement of hyperthermia-induced apoptosis by a free radical initiator, 2,2'-azobis (2-amidinopropane) dihydrochloride, in human histiocytic lymphoma U937 cells

To elucidate the mechanism how a free radical initiator, 2,2'-azobis (2-amidinopropane) dihydrochloride (AAPH), induces cell death at hyperthermic temperatures, apoptosis in a human histiocytic lymphoma cell line, U937, was investigated. Free radical formation deriving from the thermal decomposition of AAPH was examined by spin trapping with 5,5-dimethyl-1-pyrroline-N-oxide (DMPO). An assay for DNA fragmentation, observation of nuclear morphological changes, and flow cytometry for phosphatidylserine (PS) externalization were used to detect apoptosis and revealed enhancement of 44.0 degrees C hyperthermia-induced apoptosis by free radicals due to AAPH. However, free radicals alone derived from AAPH did not induce apoptosis. Hyperthermia induced the production of lipid peroxidation (LPO), an increase in intracellular Ca2+ concentration ([Ca2+]i) and enhanced expression of the type 1 inositol 1,4,5-trisphosphate receptor (IP3R1). The effects of hyperthermia on LPO and [Ca2+]i were enhanced markedly by the combination with AAPH. A significant decrease in Bcl-2 expression, increase in Bax expression, a loss of mitochondrial membrane potential (delta psi m) and a marked increase in cytochrome c expression were found only in cells treated with hyperthermia and AAPH. Although an intracellular Ca2+ ion chelator, BAPTA-AM, completely inhibited DNA fragmentation, water-soluble vitamin E, Trolox, only partially suppressed DNA fragmentation and the increase in [Ca2+]i. In contrast, LPO was inhibited completely by Trolox, but no inhibition by BAPTA-AM was found. These results suggest that apoptosis induced by hyperthermia alone is due to the increase in [Ca2+]i arising from increased expression of IP3R1 and LPO. Additional increase in [Ca2+]i due to increased LPO and the activation of mitochondria-caspase dependent pathway play a major role in the enhancement of apoptosis by the combination with hyperthermia and AAPH.

Efficiency of biological treatment affected by high strength of ammonium-nitrogen in leachate and chemical precipitation of ammonium-nitrogen as pretreatment

Leachate samples with a high strength of ammonium-nitrogen (NH4+-N) were collected from a local landfill site in Hong Kong. Two experiments were carried out to study (1) the inhibition of microbial activity of activated sludge by NH4+-N and (2) the chemical precipitation of NH4+-N from leachate as a preliminary treatment prior to the activated sludge process. The experimental results demonstrated that the efficiency of COD removal decreased from 97.7% to 78.1%, and the dehydrogenase activity of activated sludge decreased from 9.29 to 4.93 microg TF/mg MLSS, respectively, when the NH4+-N concentration increased from 53 to 800 mg/l. The experiment also demonstrated that the NH4+-N in the leachate can be quickly precipitated as MgNH4PO4 x 6H2O after addition of MgCl2 x 6H2O + Na2HPO4 x 12H2O. The NH4+-N concentration was reduced from 5618 to 112 mg/l within 15 min when a molar ratio of Mg2+:NH+:PO4(3-) = 1:1:1 was used. The optimum pH to reach the minimum solubility of MgNH4PO4 x 6H2O was found to be in the range of 8.5-9.0. Attention should be given to the high salinity formed in the treated leachate by using MgCl2 x 6H2O + Na2HPO4 x 12H2O, which may affect microbial activity in the following biological treatment processes. Using two other combinations of chemicals [MgO + 85%H3PO4 and Ca(H2PO4)2 x H2O + MgSO4 x 7H2O] could minimise salinity generation after precipitation, while they were less efficient for NH4+-N removal.

The role of intracellular Ca(2+) in apoptosis induced by hyperthermia and its enhancement by verapamil in U937 cells

PURPOSE

The relationship between apoptosis induced by 42 degrees C and 44 degrees C hyperthermia alone or in combination with verapamil and changes in intracellular Ca(2+) concentration ([Ca(2+)]i) was investigated in U937 cells.

METHODS

Apoptosis induced by hyperthermia was assessed according to DNA fragmentation, nuclear morphologic changes, and expression of phosphatidylserine on the outside plasma cell membrane. These changes were measured by flow cytometry. The [Ca(2+)]i of individual cells after hyperthermia was monitored by a digital image-analyzing technique using Fura-2.

RESULTS

Hyperthermia-induced apoptosis reached a plateau after 6 h and was found to be both time and temperature-dependent. DNA fragmentation was maximum at 44 degrees C after 30 min. Verapamil enhanced the apoptosis induced by 42 degrees C and 44 degrees C hyperthermia in normal cells and by 44 degrees C hyperthermia in thermotolerant cells. The number of cells containing higher [Ca(2+)]i (more than 200 nM) was significantly increased by hyperthermia and further elevated by the addition of verapamil in both normal and thermotolerant cells. Apoptosis induced by hyperthermia was markedly decreased by an intracellular Ca(2+) chelator, BAPTA-AM, in a dose-dependent manner.

CONCLUSION

These results indicate that [Ca(2+)]i increase plays a crucial role in apoptosis induced by hyperthermia and the combined treatment with verapamil in normal and thermotolerant U937 cells. Furthermore, hyperthermia-combined drug therapy has potential significance in cancer therapy.

Apoptosis induced by cadmium in human lymphoma U937 cells through Ca2+-calpain and caspase-mitochondria- dependent pathways

Apoptosis induced by cadmium has been shown in many tissues in vivo and in cultured cells in vitro. However, its molecular mechanism is not fully understood. When the human histiocytic lymphoma cell line U937 was treated with cadmium for 12 h, evidence of apoptotic features, including change in nuclear morphology, DNA fragmentation, formation of DNA ladder in agarose gel electrophoresis, and phosphatidylserine externalization, were obtained. Moreover, loss of the mitochondrial membrane potential (Deltapsi(m)) was observed in the cadmium-treated cells and was inhibited by a broad caspase inhibitor (Z-VAD-FMK). Caspase inhibitors suppressed the DNA fragmentation in the order of Z-VAD-FMK > caspase-8 inhibitor > caspase-3 inhibitor. Expression of Bcl-x(L) and Bid decreased significantly in the cadmium-treated cells, although no apparent change in Bcl-2 and Bax expression was found. Tetrakis-(2-pyridylmethyl) ethylendiamine, a cell-permeable heavy metal chelator, partially reversed the increase of fluorescence of Fura-2 in the cadmium-treated cells. In addition, verapamil (70 microm), a voltage-dependent Ca(2+) channel blocker, inhibited the DNA fragmentation induced by cadmium less than 100 microm and decreased the fluorescence of Fura-2. Cadmium up-regulated the expression of type 1 inositol 1,4,5-trisphosphate receptor (IP(3)R) but not type 2 or type 3 IP(3)R. Calpain inhibitors I and II partially prevented DNA fragmentation. No effects of Z-VAD-FMK on the expression of type 1 IP(3)R or of calpain inhibitors on the loss of Deltapsi(m) were observed. These results suggest that cadmium possibly induced apoptosis in U937 cells through two independent pathways, the Ca(2+)-calpain-dependent pathway and the caspase-mitochondria-dependent pathway.