Flooding duration affects the temperature sensitivity of soil extracellular enzyme activities in a lakeshore wetland in Poyang Lake, China.

Extracellular enzymes play central roles in the biogeochemical cycles in wetland ecosystems. Their activities are strongly impacted by hydrothermal conditions. Under the ongoing global change, many studies reported the individual effects of flooding and warming on extracellular enzyme activities, however, few researches investigated their interactive effects. Therefore, the current study aims to determine the responses of extracellular enzyme activities to warming in wetland soils under divergent flooding regimes. We investigated the temperature sensitivity of seven extracellular enzymes related to carbon (α-glucosidase, AG; ß-glucosidase, BG; cellobiohydrolase, CBH; ß-xylosidase, XYL), nitrogen (ß-N-acetyl -glucosaminidase, NAG; leucine aminopeptidase, LAP), and phosphorus (Phosphatase, PHOS) cycling along the flooding duration gradient in a lakeshore wetland of Poyang Lake, China. The Q10 value, calculated using a temperature gradient (10, 15, 20, 25, and 30 °C), was adopted to represent the temperature sensitivity. The average Q10 values of AG, BG, CBH, XYL, NAG, LAP, and PHOS in the lakeshore wetland were 2.75 ± 0.76, 2.91 ± 0.69, 3.34 ± 0.75, 3.01 ± 0.69, 3.02 ± 1.11, 2.21 ± 0.39, and 3.33 ± 0.72, respectively. The Q10 values of all the seven soil extracellular enzymes significantly and positively correlated with flooding duration. The Q10 values of NAG, AG and BG were more sensitive to the changes in flooding duration than other enzymes. The Q10 values of the carbon, nitrogen, and phosphorus-related enzymes were mainly determined by flooding duration, pH, clay, and substrate quality. Flooding duration was the most dominant driver for the Q10 of BG, XYL, NAG, LAP, and PHOS. In contrast, the Q10 values of AG and CBH were primarily affected by pH and clay content, respectively. This study indicated that flooding regime was a key factor regulating soil biogeochemical processes of wetland ecosystems under global warming.

Microbiome-metabolome analysis reveals cervical lesion alterations.

Cervical cancer (CC) continues to be one of the most common cancers among females worldwide. It takes a few years or even decades for CC to arise in a minority of women with cervical precancers. An increasing corpus of studies today indicates that local microecology and carcinogenesis are intimately related. To investigate the changes in cericovaginal microecology with the development of cervical cancer, we performed 16S rDNA sequencing and metabolomic analysis in cericovaginal fluid from 10 LSIL patients, 10 HSIL patients, 10 CC patients and 10 healthy controls to reveal the differential flora and metabolites during cervical carcinogenesis. Carcinogenesis is associated with alterations in microbiome diversity, individual taxa, and functions with notable changes in Lactobacillus, Prevotella and Aquabacterium, as well as in cervicovaginal metabolites that correlate with cervicovaginal microbial patterns. Increased bacterial diversity and a decline in the relative abundance of Lactobacillus, the dominant species in the cericovaginal flora, are observed when cervical lesions advance. According to KEGG pathway enrichment analysis, lipids and organic acids change as cervical cancer progresses, and the phenylalanine, tyrosine, and tryptophan biosynthesis pathway is essential for the development of cervical cancer. Our results reveal that microbic and metabolomic profiling is capable of distinguishing CC from precancer and highlights potential biomarkers for the early detection of cervical dysplasia. These differential microorganisms and metabolites are expected to become a potential tool to assist in the diagnosis of cervical cancer.

Characterization of Vaginal Microbiota in Third Trimester Premature Rupture of Membranes Patients through 16S rDNA Sequencing.

In China, premature rupture of membranes (PROM) counts as a major pregnancy complication in China and usually results into adverse pregnancy outcomes. We analysed the vagina microbiome composition using 16S rDNA V3−V4 amplicon sequencing technology, in this prospective study of 441 women in their third trimester of pregnancy. We first divided all subjects into PROM and HC (healthy control) groups, in order to investigate the correlation of vagina microbiome composition and the development of PROM. We found that seven pathogens were higher in the PROM group as compared to the HC group with statistical significance. We also split all subjects into three groups based on Lactobacillus abundance-dominant (Lactobacillus > 90%), intermediate (Lactobacillus 30−90%) and depleted (Lactobacillus < 30%) groups, and explored nine pathogenic genera that were higher in the depleted group than the intermediate and dominant groups having statistical significance. Finally, using integrated analysis and logistics regression modelling, we discovered that Lactobacillus (coeff = −0.09, p = 0.04) was linked to the decreased risk of PROM, while Gardnerella (coeff = 0.04, p = 0.02), Prevotella (coeff = 0.11, p = 0.02), Megasphaera (coeff = 0.04, p = 0.01), Ureaplasma (coeff = 0.004, p = 0.01) and Dialister (coeff = 0.001, p = 0.04) were associated with the increased risk of PROM. Further study on how these pathogens interact with vaginal microbiota and the host would result in a better understanding of PROM development.

NiCoSe4nanoparticles derived from nickel-cobalt Prussian blue analogues on N-doped reduced graphene oxide for high-performance asymmetric supercapacitors.

Synthesis of NiHCCo precursors via simple co-precipitation and nickel-cobalt tetraselenide composites grown on nitrogen-doped reduced graphene oxide (NiCoSe4/N-rGO) were fabricated using solvothermal method. The introduction of N-rGO used as a template effectively prevented agglomeration of NiCoSe4nanoparticles and provided more active sites, which greatly increased the electrochemical and electrical conductivity for NiCoSe4/N-rGO. NiCoSe4/N-rGO-20 presents a remarkably elevated specific capacity of 120 mA h g-1under current density of 1 A g-1. NiCoSe4/N-rGO-20 demonstrates an excellent cycle life and achieves a remarkable 83% retention rate over 3000 cycles with 10 A g-1. NiCoSe4/N-rGO-20//N-rGO asymmetric supercapacitor was constructed based on the NiCoSe4/N-rGO-20 as an anode, N-rGO as cathode by using 2 mol l-1KOH as an electrolyte. NiCoSe4/N-rGO-20//N-rGO ASC demonstrates an ultra-big energy density of 14 Wh kg-1and good circulation stability in the power density of 902 W kg-1. It is doubled in comparison to the NiCoSe4/N-rGO-20//rGO asymmetric supercapacitor (7 Wh kg-1). The NiCoSe4/N-rGO-20//N-rGO ASC capacity retention is still up to 93% over 5000 cycles (5 A g-1). The results reveal that this device would be a prospective cathode material of supercapacitors in actual applications.

Influences of submerged plant collapse on diet composition, breadth, and overlap among four crane species at Poyang Lake, China.

BACKGROUND: Interannual variation in resource abundance has become more unpredictable, and food shortages have increasingly occurred in the recent decades. However, compared to seasonal fluctuations in resource abundance, the influences of interannual variation in resource abundance on the dietary niches of consumers remain poorly understood. Poyang Lake, China, is a very important wintering ground for the globally endangered Siberian Crane (Leucogeranus leucogeranus), White-naped Crane (Grus vipio), and Hooded Crane (G. monacha), as well as the non-endangered Eurasian Crane (G. grus). Tubers of Vallisneria spp., the dominant submerged macrophytes at Poyang Lake, is an important food for cranes. Nevertheless, submerged macrophytes have experienced serious degradation recently. In this study, we used metabarcoding technology to explore the consequences of Vallisneria tuber collapse on the diet compositions, breadths, and overlaps of the four crane species based on fecal samples collected in winter 2017 (a year with tuber collapse) and winter 2018 (a year with high tuber abundance). RESULTS: Compared to previous studies, our study elucidates crane diets in an unprecedented level of detail. Vallisneria tubers was confirmed as an important food source of cranes. Surprisingly, the grassland plant Polygonum criopolitanum was also found to be an important food source in the feces of cranes. Agricultural fields were important foraging sites for Siberian Cranes, White-naped Cranes, and Hooded Cranes, providing foods that allowed them to survive in winters with natural food shortages. However, the three crane species preferred natural wetlands to agricultural fields when the abundance of natural foods was high. The abundance of Vallisneria tubers, and probably P. criopolitanum, greatly influenced the dietary compositions, breadths and overlap of cranes. During periods of preferred resource shortage, White-naped Cranes and Hooded Cranes widened their dietary niches, while Siberian Cranes maintained a stable niche width. The dietary niche overlap among crane species increased substantially under conditions of plentiful preferred food resources. CONCLUSIONS: Our study emphasizes the superior quality of natural wetlands compared to agricultural fields as foraging habitats for cranes. To provide safer and better foraging areas for cranes, it is urgent to restore the submerged plants at Poyang Lake. While high dietary niche overlap is often interpreted as intense interspecific competition, our study highlights the importance of taking food abundance into account.

Integrated metagenomics and metabolomics analysis of third-trimester pregnant women with premature membrane rupture: a pilot study.

BACKGROUND: Premature rupture of membranes (PROM) is a major pregnancy complication in China and usually leads to adverse pregnancy outcomes. The major aim of this study was to search for microorganisms and their related metabolites that have direct relationship with PROM. METHODS: For vaginal discharge samples, metagenomics sequencing was applied to identify microorganisms that were enriched in PROM subjects, and untargeted metabolomics was applied to characterize the metabolites changes in PROM subjects compared to healthy controls (HC). Correlation analysis was then used to explore the relationship between these microorganisms and metabolites changes. RESULTS: Two upstream metabolites of glycolysis, N-acetyl-D-galactosamine (GalNAc) and sucrose, were found downregulated in the PROM group (P=0.04 and P=0.041, respectively). Higher percentages of conditional pathogens, such as of Streptococcus (8.4% vs. 6.1% in HC group, P=0.15) and Chlamydia (4.3% vs. 2.3% in HC group, P=0.07) were found in PROM group. Other common conditional pathogens including Prevotella, Staphylococcus, Mycobacterium and Enterobacter, were also higher in PROM group, although their absolute percentages were low and the differences did not reach statistical significance due to relative small sample size. Correlation analysis further demonstrated a positive correlation of downregulation of glycolysis metabolites with higher percentage of conditional pathogens. CONCLUSIONS: Integrated metagenomics and metabolomics analysis can be used to track the subtle changes in the vaginal microenvironment. Downregulation of glycolysis substrates (GalNAc and sucrose) and increase of related pathogenic microorganisms (Streptococcus and Chlamydia) could serve as early warning biomarkers of PROM.

Detection of Vaginal Metabolite Changes in Premature Rupture of Membrane Patients in Third Trimester Pregnancy: a Prospective Cohort Study.

Premature rupture of membranes (PROM) is usually associated with pregnant and neonatal complications. Most of the PROM cases are caused by ascending asymptomatic genital infection. In China, PROM (15.3%) is more common than spontaneous preterm labor (7.3%) and leads to more adverse pregnancy outcomes. Here, we designed a prospective cohort study to measure the metabolomics changes in vaginal swab samples and explored their potential contribution to PROM. A total of 260 differentially expressed metabolites were identified and further analyzed. In the PROM group, N-acetyl-D-galactosamine and sucrose were downregulated (P = 0.0025, P = 0.0195, respectively), both of which are the upstream metabolites of the glycolysis pathway. Furthermore, estriol 3-sulfate 16-glucuronide (P = 0.0154) and 2-methoxy-17beta-estradiol 3-glucosiduronic acid (P = 0.004), two final metabolites in steroid hormone biosynthesis, were both downregulated in the PROM group. Finally, we found two catechin metabolites (epigallocatechin-7-glucuronide, P = 0.0009; 4'-methyl-epigallocatechin-7-glucuronide, P = 0.01) as well as DL-citrulline (P = 0.0393) were also significantly downregulated in the PROM group compared with the healthy control (HC) group, which are related to important antioxidant and anti-inflammatory activities in the human body. Altogether, metabolite changes in glycolysis, steroid hormone biosynthesis, and antioxidant/anti-inflammatory pathways may contribute to (or be a consequence of) vaginal dysbiosis and PROM. Metabolite pathway analysis is a new and promising approach to further investigate the mechanism of PROM and help prevent its unfavorable pregnant outcomes at a functional level. Trial registration number: ChiCTR2000034721.

Palygorskite-anchored Pd complexes catalyze the coupling reactions of pyrimidin-2-yl sulfonates.

In this work, an anchored Pd complex (PGS-APTES-Pd(OAc)2) was prepared via simple and green steps from the natural clay mineral palygorskite and was well characterized by XPS, XRD, IR, SEM, and EDX. This complex was further utilized as a fine catalyst for the C-C/C-N coupling reactions of pyrimidin-2-yl sulfonates. Subsequently, the cyclic utilization test indicated the high stability and sustainability of this PGS-APTES-Pd(OAc)2 catalyst, and no activation was required in the recycling process, providing an applicable and reusable catalyst in organic synthesis.

Contamination levels and human health risk assessment of toxic heavy metals in street dust in an industrial city in Northwest China.

This study investigated the content, distribution, and contamination levels of toxic metals (Cd, Cr, Cu, Pb, and Zn) in street dust in Lanzhou, an industrial city in Northwest China. Meanwhile, the risk these metals posed to the urban ecosystem and human health was also evaluated using the potential ecological risk index and human exposure model. Results showed that concentrations of these metals in the dust are higher than the background value of local soil, with Cu having the highest levels. The districts of Anning and Xigu had the most extreme levels of contamination, while Chengguan and Qilihe districts were lightly contaminated, which can be partly attributed to human activities and traffic densities. In comparison with the concentrations of selected metals in other cities, the concentrations of heavy metals in Lanzhou were generally at moderate or low levels. Heavy metal concentration increased with decreasing dust particle size. The pollution indices of Cr, Cd, Cu, Pb, and Zn were in the range of 0.289-2.09, 0.332-2.15, 1.38-6.21, 0.358-2.59, and 0.560-1.83 with a mean of 1.37, 1.49, 3.18, 1.48, and 0.897, respectively. The geo-accumulation index (I geo) suggested that Zn in street dust was of geologic origin, while Cd, Cr, Pb, and Cu were significantly impacted by anthropogenic sources. The comprehensive pollution index showed that urban dust poses a high potential ecological risk in Lanzhou. Non-carcinogenic and carcinogenic effects due to exposure to urban street dust were assessed for both children and adults. For non-carcinogenic effects, ingestion appeared to be the main route of exposure to dust particles and thus posed a higher health risk to both children and adults for all metals, followed by dermal contact. Hazard index values for all studied metals were lower than the safe level of 1, and Cr exhibited the highest risk value (0.249) for children, suggesting that the overall risk from exposure to multiple metals in dust is low. The carcinogenic risk for Cd and Cr was all below the acceptable level (< 10-6).

Distribution, compositional pattern and sources of polycyclic aromatic hydrocarbons in urban soils of an industrial city, Lanzhou, China.

The level, distribution, compositional pattern and possible sources of polycyclic aromatic hydrocarbons (PAHs) in Lanzhou urban soil of Northwest China were investigated in this study. The total level of 22 PAHs ranged from 115 to 12,100 µg kg(-1) and that of 16 priority PAHs from 82.4 to 10,900 µg kg(-1). Seven carcinogenic PAHs generally accounted for 6.18-57.4% of total 22 PAHs. Compared with data from those reported about urban areas, PAH contamination in Lanzhou urban soils was moderate. Among different functional areas, higher level of PAHs was found along roadsides and in the industrial district (p<0.01), while lower levels were detected in the commercial, park and residential districts. The composition of PAHs was characterized by high molecular weight PAHs (≥4 rings), among which fluoranthene, benz[a]anthracene and phenanthrene were the most dominant components. Correlation analysis suggested that low molecular weight PAHs and high molecular weight PAHs originated from different sources and further corroborated that TOC was an important factor in the accumulation of PAHs in soil. Isomer ratios and principal component analysis indicated that PAHs in urban soil derived primarily from emissions resulting from the combustion of biomass, coal and petroleum products. Toxic equivalent concentrations (BaP(eq)) of soil PAHs ranged from 6.12 to 1302 µg BaP(eq) kg(-1), with a mean of 138 µg BaP(eq) kg(-1). The results suggested that human exposure to those soils which polluted by high concentrations of PAHs through direct ingestion or inhalation of suspended soil particles probably poses a significant risk to human health from the carcinogenic effects of PAHs.

[Effect of Biochar on Adsorption Behavior of Nonylphenol onto Loess Soil in Northwest China].

In the present study, nonylphenol (NP) was selected as the target pollutant to investigate the effect of biochar produced from wheat residue at different temperatures on loess soil based on the batch experiments. The research basically included adsorption kinetic, thermodynamic and some influencing factors such as biochar with different pyrolysis temperature, particle size and pH value. The results showed that the adsorption reaction of NP onto loess soil without biochar was 10 h during fast reaction, and after the addition of biochar into loess soil, the fast reaction time of NP adsorption was shortened. Meanwhile, in the fast stage the adsorption reaction of NP onto loess soil with biochar was significantly higher than loess soil without biochar, while the difference of adsorption capacity was small at different carbonization temperatures. The adsorption reaction of NP onto loess soil by adding biochar could be well described by the pseudo-second-order kinetics model and reached equilibrium in 16 h. The kinetic data showed that the adsorption of NP accorded well with the Freundlich isotherm model. The saturated adsorption capacity was improved as temperature increased with or without biochar. Thermodynamic parameter analysis indicated Gibbs free energy ΔGθ<0, entropy ΔHθ>0 and enthalpy ΔSθ>0, demonstrating it was a spontaneous, endothermic and chaos-increasing adsorption process. At the same temperature, the adsorption capacity of NP in loess soils increased dramatically with the increase of carbonization temperature. The smaller particle size of the loess with the addition of biochar, the better the adsorption of NP. When the pH value was 4 to 7, the adsorption capacity of NP onto loess soil by adding biochar showed an increasing trend; in the pH range of 7 to 10, the adsorption saturation capacity decreased with the increase of pH value. Therefore, the adsorption of NP on loess with the addition of biochar had the best adsorption effect in the neutral range. Acid and alkalinity were not conducive to the adsorption of NP.

[Adsorption Behavior of p-hydroxy Biphenyl onto Sediment of the Yellow River in Lanzhou].

In order to study the adsorption behavior of organic pollutants in sediment of the Yellow River in Lanzhou, p-hydroxy biphenyl (PHB) was selected as the typical organic pollutants to understand the adsorption kinetics and thermodynamics of PHB onto sediment of the Yellow River in Lanzhou based on the batch experiments. Meanwhile, the effects of systemic temperature, such as the particle size, the initial concentration of PHB, pH value, and the ionic strength, were also investigated for the adsorption of PHB onto sediment of the Yellow River. The results indicated that the adsorption kinetics of PHB onto sediment of the Yellow River could be better described by Pseudo-second-order model, and the boundary layer and intraparticle diffusion were both involved in the adsorption kinetic process. The adsorption thermodynamics of PHB onto sediment of the Yellow River were fitted well with the Langmuir model(R2>0.974), which was a single molecular layer adsorption process. The average adsorption free energy E ranged from 0.913 to 1.00 kJ·mol-1 when the systemic temperatures increased from 25℃ to 45℃, suggesting a physical adsorption. Thermodynamic parameter analysis indicated that Gibbs free energy (ΔGθ) and Entropy (ΔHθ) were less than zero, but Enthalpy (ΔSθ) was more than zero in the adsorption process, which tended to prove the spontaneous nature of the adsorption process, the endothermic nature of the adsorption process and the increased randomness at the sediment surface. Furthermore, the smaller the particle size, the greater the adsorption capacity of the PHB. The adsorption capacity was increased with the increase of the initial concentration of PHB. When the pH value in a range of 4.23 to 7.00, the adsorption capacity of PHB showed a slow decreasing trend, while the decreasing was sharp when pH value was greater than 7.00, and the adsorption capacity was almost zero when pH value was about 10.3. With the increase of ionic strength, the adsorption amount of PHB was also increased, but when the ionic strength increased to a certain value, due to the competitive adsorption, the adsorption of PHB onto sediments would be inhibited, resulting in decreased amount of adsorption.

[Adsorption and Influential Factors of Diuron on the Loess Soil by Adding Different Biochar Prepared at Varying Temperatures].

The primary objective of this study was to investigate the effect of biochar, produced from maize and pine needles residue at different temperatures, on the adsorption of diuron onto loess soil. Meanwhile, the effect of the systemic temperature, pH values and the initial concentration of diuron were also investigated for the adsorption of diuron onto losses soil. And Kinetic parameters, such as rate constants, equilibrium adsorption capacities and related correlation coefficients were also calculated and discussed. The results showed that the adsorption of diuron onto loess soil by adding biochar could be described by the pseudo-second-order kinetic model, and followed the intraparticle diffusion model, but diffusion was not only the rate-controlling step. The adsorption process was divided into fast (0-8 h) and slow (8-12 h) adsorption stages, and equilibrium was reached at around 12 h. The adsorption thermodynamics of diuron onto loess soil was nonlinear by nature, and well fitted with the Freundlich isothermal model. Thermodynamic parameter analysis of diuron onto loess soil by adding biochar showed that Gibbs free energy (ΔGθ) was less than zero, while Enthalpy (ΔSθ) and Entropy (ΔHθ) were greater than zero, indicating a spontaneous endothermic adsorption, which increased the degree of disorder during the process. And Thermodynamic parameter analysis of diuron onto loess soil without adding biochar showed that Gibbs free energy (ΔGθ) and Entropy (ΔHθ) were less than zero, while Enthalpy (ΔSθ) was greater than zero. The average adsorption free energy E was in range of 1.29-5.00 kJ·mol-1 when the temperatures increased from 25 to 45℃, indicated that adsorption of diuron onto loess was a physical adsorption. The results also suggested that the influencing factors of diuron had significant effects on the adsorptive behaviors of diuron on loess soil. With increasing pyrolysis temperature of biochar, the equilibrium concentration of diuron in water decreased, while the amount of adsorption on loess soil increased. When the initial concentration of diuron increased from 0.5 mg·L-1 to 6 mg·L-1, the adsorption capacity of diuron onto loess soil by adding biochar showed a rapidly increasing trend. When the initial concentration increased. the adsorption capacity showed a slow increasing trend and gradually tended to be stable. In the pH range of 3 to 10, the adsorption capacity of diuron onto loess soil by adding biochar changed a little.

Status, source and health risk assessment of polycyclic aromatic hydrocarbons in street dust of an industrial city, NW China.

The status, source and health risk of street-dust-borne polycyclic aromatic hydrocarbons (PAHs) in Lanzhou of Northwest China were investigated. The total level of the 21 PAHs ranged from 1470 to 13,700 µg kg(-1) and that of the 16 priority PAHs from 1240 to 10,700 µg kg(-1). Higher levels of PAHs were mainly distributed in the Chengguan and Qilihe districts at Lanzhou central areas, and the lower levels were in Anning and Xigu districts. The level of seven potential carcinogenic PAHs generally accounted for 35-40 percent of total PAHs, and the PAHs contained two to four rings, mainly phenanthrene, benzo[b]fluoranthene and fluoranthene. The total level of PAHs increased with the decreasing particle size in the street dust. The correlation analysis suggested that the total organic carbon (TOC) was only slightly affected the PAH accumulation in street dust. The isomer ratios and principal component analysis indicated that the dust-borne PAHs in the dust were derived primarily from the combustion of biomass, coal and petroleum emission. The toxic equivalent concentrations (BaP(eq)) of dust-borne PAHs ranged from 115 to 827 µg BaP(eq) kg(-1), with a mean of 300 µg BaP(eq) kg(-1). The 95 percent upper confidence limit of Incremental Lifetime Cancer Risk due to human exposure to urban surface dust-borne PAHs in Lanzhou urban area was 2.031 × 10(-6) for children and 1.935 × 10(-6) for adults.

Neohesperidin induces cellular apoptosis in human breast adenocarcinoma MDA-MB-231 cells via activating the Bcl-2/Bax-mediated signaling pathway.

Neohesperidin, a flavonoid compound found in high amounts in Poncirus trifoliata, has free radical scavenging activity. For the first time, our study indicated that neohesperidin also induces cell apoptosis in human breast adenocarcinoma MDA-MB-231 cells, which was possibly mediated by regulating the P53/Bcl-2/Bax pathway. MDA-MB-231 cells were subjected to treatment with neohesperidin. MTT and Trypan blue exclusion assays were applied to assess the cell viability. The morphological changes of cells were observed using an inverted microscope, and cell apoptosis was detected by flow cytometric analysis. Immunoblot analysis was conducted to evaluate the protein expressions of apoptosis-related genes, including P53, Bcl-2 and Bax. Our results indicated that the proliferation of MDA-MB-231 cells was inhibited by the treatment with neohesperidin in a time- and dose-dependent manner. The IC50 values of neohesperidin at 24 and 48 h were 47.4 +/- 2.6 microM and 32.5 +/- 1.8 microM, respectively. The expressions of P53 and Bax in the neohesperidin-treated cells were significantly up-regulated, while that of Bcl-2 was down-regulated. Our study suggested that neohesperidin could induce apoptosis of MDA-MB-231 cells, a process which was associated with the activation of the Bcl-2/Bax-mediated signaling pathway.

Study on the mutations in the D-loop region of mitochondrial DNA in cervical carcinoma.

BACKGROUND: Study on genesis and development of tumor is mainly concentrated on gene mutation in nucleus. But in recent years, the role of mitochondrial DNA (mtDNA) mutation in tumor genesis has been given more attention, which is the only extra-nucleus DNA in cells of higher animals. Carcinoma of the uterine cervix is a common tumor in gynecology. There are few reports of mtDNA mutation in this area. The focus of this study was to investigate the mitochondrial DNA mutation in tumor tissues of cervical carcinomas patients and their relationship to tumorigenesis and tumor development. METHODS: The D-loop region of 24 cervical carcinomas together with the adjacent normal tissues were amplified by PCR and sequenced. RESULTS: Among the 24 cervical carcinomas, 30 mutations were identified with the mutations rate of 37.5% (9/24).There were eight microsatellite instabilities among the mutations and 13 new polymorphisms which were not reported previously in the GeneBank. CONCLUSIONS: The D-loop region of mitochondrial DNA is a highly polymorphoric and mutable region and the mutations rate is relatively high in patients with cervical carcinomas.

Sorption of ionizable organic compounds on HDTMA-modified loess soil.

A natural loess soil was modified using a cationic surfactant, hexadecyltrimethylammonium (HDTMA) bromide. Sorption of ionizable organic compounds (IOCs), 2,4-dichlorophenol (DCP), p-nitroaniline (NA) and benzoic acid (BA), on the modified soil was determined under different pH conditions. The objective of this study was to examine the sorptive characteristics of IOCs on HDTMA-modified loess soil as a function of pH in an attempt to establish the sorptive models and mechanisms for predicting the sorptive behaviors of IOCs on the HDTMA-modified loess soil. The sorption isotherms of DCP, NA and BA with the soil were obtained using the batch equilibration method. Results indicated that the sorption isotherms of IOCs, regardless of ionic or neutral forms, were non-linear and obeyed to the Freundlich equation. A model describing the sorption of IOCs on the HDTMA-modified loess soil was derived from the experimental data. The model well predicted the sorption of DCP from individual sorption of both ionic and neutral species of the IOC. In binary solute systems, sorption of NA was reduced in the presence of DCP or BA, which indicated that DCP and BA had a competitive effect on the sorption of NA on the HDTMA-modified loess soil. The effect of DCP on the sorption of NA gradually increased with decreasing pH from 10.8 to 6.7, suggesting a stronger effect of neutral DCP than that of the ionic species on the sorption of NA. Modification of loess soil may effectively immobilize ionizable organic contaminants in soil environment.

[Research advances in biodegradation of chlorophenols in environment].

This paper examines the biodegradation of chlorophenols by microbes and deals with the chlorophenols-degrading microbes and the usage of biotechnology with special emphasis on degradation mechanisms. Dechlorination is the first critical step in the bacterial degradation of many chloroniated pollutans. Under aerobic condition, the degradation of mono- and dichlorophenols is shown to be initiated by oxygenation into chlorocatechols, and dechlorination occurs only after ring cleavage of the chlorocatechols. The degradation of polychlorinated phenols starts by hydrolytic para-hydroxylation, yielding chlorinated para-hydroquinone. The anaerobic biodegradation of chlorophenols occurs by reductive dechlorination, a process by which chlorines are replaced with hydrogen.

Sorption behaviors of aromatic anions on loess soil modified with cationic surfactant.

Modification of soils with hydrophobic cationic surfactants is an effective approach for enhancing the sorptive capabilities of soil in the vadose zone for the purpose of retaining organic contaminants prior to cleanup. The objective of this study was to examine the sorptive behavior of the cationic surfactant-modified loess soil for aromatic anions in the aqueous phase in an attempt to define the sorptive mechanisms. Some dominant factors governing the sorption, such as ionic strength and divalent heavy metal cation, were investigated. The sorption isotherms of 2,4-dinitrophenol (DNP) and benzoic acid (BA) in the modified soil samples were obtained using the batch equilibration method. Under the laboratory conditions, the modified loess soil utilized in this study was prepared by replacing the cations of loess soil with a cationic surfactant-hexadecyltrimethylammonium (HDTMA) bromide. The acidic aromatic compounds, DNP and BA existing as aromatic anions in the natural mixture of loess soil and aqueous phase, were selected as indicator compounds to measured the sorption behaviors of aromatic anions on the HDTMA-modified loess soil. The results confirmed that the sorptive capabilities of aromatic anions in loess soil were greatly enhanced by modification with HDTMA. The increase of ionic strength and the addition of divalent heavy metal cation Zn(2+) significantly increased the sorption of aromatic anions on the HDTMA-modified loess soil. In binary solute systems, the sorbed amounts either of DNP or BA on the HDTMA-modified loess soil were reduced if two compounds existed simultaneously in the soil. This results indicated that competitive adsorption between the two aromatic anions occurred in soil matrix.