Effects of slag and biochar amendments on microorganisms and fractions of soil organic carbon during flooding in a paddy field after two years in southeastern China.

Incorporating amendments of industrial waste such as biochar and steel slag in cropland has been used to enhance the storage of soil organic carbon (SOC) while sustaining crop production. Short-term laboratory and field studies have identified important influences of biochar on active SOC fractions associated with soil microbial activity in paddy soils, but the long-term effects remain poorly understood. To address these knowledge gaps, we examined the effects of slag, biochar, and slag+biochar treatments on total SOC concentration, active SOC fractions and soil microbial communities in a paddy field two years after incorporation. Across both two seasons, the addition of slag, biochar, slag+biochar increased soil salinity by 26-80%, 1.3-37% and 42-79%, and also increased soil pH by 0.8-5.7%, 2.1-2.4% and 4.0-6.3%, respectively, relative to the control. SOC concentration was higher in the slag, biochar, and slag+biochar treatments across both rice seasons by 4.3-5%, 0.5-17% and 4.3-7%, respectively. Soil C-pool activity and C-pool management indices in the late paddy season were significantly lower in the slag+biochar treatment than the control by 26.3 and 21.3%, respectively, indicating that the amendments contributed to the stability of SOC. The C concentrations of the biochar and slag amendments affected bacterial abundance more than fungal abundance and affected C cycling. Our study suggests that combined slag and biochar amendments may increase bacterial abundance that may maintain SOC storage and reduce the abundances of potential SOC decomposers in key functional genera, indicating strong coupling relationships with changes of soil properties such as salinity, pH, and SOC concentration. These outcomes due to the amendments (e.g. slag+biochar) may increase microbial C-use efficiency and support the stability of active SOC fractions, with opportunities for long-term C sequestration.

Effects of nitrogen-enriched biochar on rice growth and yield, iron dynamics, and soil carbon storage and emissions: A tool to improve sustainable rice cultivation.

Biochar is often applied to paddy soils as a soil improver, as it retains nutrients and increases C sequestration; as such, it is a tool in the move towards C-neutral agriculture. Nitrogen (N) fertilizers have been excessively applied to rice paddies, particularly in small farms in China, because N is the major limiting factor for rice production. In paddy soils, dynamic changes in iron (Fe) continuously affect soil emissions of methane (CH4) and carbon dioxide (CO2); however, the links between Fe dynamics and greenhouse gas emissions, dissolved organic carbon (DOC), and rice yields following application of biochar remain unclear. The aims of this study were to examine the effects of two rates of nitrogen (N)-enriched biochar (4 and 8 t ha-1 y-1) on paddy soil C emissions and storage, rice yields, and Fe dynamics in subtropical early and late rice growing seasons. Field application of N-enriched biochar at 4 and 8 t ha-1 increased C emissions in early and late rice, whereas application at 4 t ha-1 significantly increased rice yields. The results of a culture experiment and a field experiment showed that the application of N-enriched biochar increased soil Fe2+concentration. There were positive correlations between Fe2+concentrations and soil CO2, CH4, and total C emissions, and with soil DOC concentrations. On the other way around, these correlations were negative for soil Fe3+concentrations. In the soil culture experiment, under the exclusion of plant growth, N-enriched biochar reduced cumulative soil emissions of CH4 and CO2. We conclude that moderate inputs of N-rich biochar (4 t ha-1) increase rice crop yield and biomass, and soil DOC concentrations, while moderating soil cumulative C emissions, in part, by the impacts of biochar on soil Fe dynamics. We suggest that water management strategies, such as dry-wet cycles, should be employed in rice cultivation to increase Fe2+ oxidation for the inhibition of soil CH4 and CO2 production. Overall, we showed that application of 4 t ha-1 of N-enriched biochar may represent a potential tool to improve sustainable food production and security, while minimizing negative environmental impacts.

Optimization of media composition for enhancing tetracycline degradation by Trichosporon mycotoxinivorans XPY-10 using response surface methodology.

The objective of the study was to improve tetracycline degradation efficiency by Trichosporon mycotoxinivorans XPY-10 using statistical experimental designs. Different culture conditions (FeSO4, pH and glucose) were optimized for tetracycline biodegradation and the mutual interactions between these three variables were analysed using Box-Behnken design (BBD) and response surface methodology (RSM). The results showed that the empirical model was suitable for experimental data, and the maximum tetracycline degradation efficiency by XPY-10 was 95.18% under the optimum conditions of 0.02% of FeSO4, pH 7.83 and 0.28% of glucose, which was further verified by experiments. This study indicated the excellent ability of XPY-10 in degrading tetracycline and theoretical support for the follow-up practice to remediate tetracycline contaminated environment.

Steel slag and biochar amendments decreased CO2 emissions by altering soil chemical properties and bacterial community structure over two-year in a subtropical paddy field.

Waste amendments, such as steel slag and biochar, have been reported as a strategy for improving soil fertility, crop productivity, and carbon (C) sequestration in agricultural lands. However, information regarding the subsequent effects of steel slag and biochar on C cycling and the underlying microbial mechanisms in paddy soils remains limited. Hence, this study aimed to examine the effect of these waste amendments (applied in 2015-2017) on total soil CO2 emissions, total and active soil organic C (SOC) contents, and microbial communities in the early and late seasons in a subtropical paddy field. The results showed that despite the exogenous C input from these waste amendments (steel slag, biochar and slag + biochar), they significantly (P < 0.05) decreased total CO2 emissions (e.g., by 41.9-59.6% at the early season), compared to the control soil. These amendments also significantly (P < 0.001) increased soil salinity and pH. The increased soil pH had a negative effect (r = -0.37, P < 0.05) on microbial biomass C (MBC). The biochar and slag + biochar treatments (cf. control) significantly (P < 0.001) increased SOC contents in the both seasons. The amendments altered the soil microbial community structure that associated with soil C cycling: (1) all three amendments increased the relative abundance of Agromyces and Streptomyces, which was associated with higher soil pH (cf. control); and (2) biochar and slag + biochar treatments caused a higher relative abundance of Sphingomonas, which was supported by high SOC contents under those amendments. Overall, this study demonstrated that the steel slag and biochar amendments altered microbial community composition due to changes in key soil properties, such as salinity, pH and SOC contents, with implications for increasing soil C stocks while mitigating CO2 emissions in the paddy field.

Coupled steel slag and biochar amendment correlated with higher methanotrophic abundance and lower CH4 emission in subtropical paddies.

Aerobic methanotrophs in paddies serve as methane (CH4) filters and thereby reduce CH4 emissions. Amending soil with waste products can mitigate CH4 emissions in crops, but little is known about the impacts of amendments with steel slag and biochar on the populations and activities of aerobic methanotrophs in rice cropland. We used real-time quantitative PCR detecting system and high-throughput sequencing to determine the effects of slag and biochar amendments on CH4 emission, abundance, and community structure of methanotrophs, and the relationships between soil properties and the abundance and community composition of methanotrophs during the rice growing season in both early and late paddies. Soil salinity and pH were significantly higher for an amendment with both slag and biochar than the control in both the early and late paddies, and pH was significantly higher for a slag amendment in the late paddy. Cumulative CH4 emission was lower for the slag and slag + biochar amendments than the control in early paddy by-34.1%. Methanotrophic abundance was three- and sixfold higher for the slag + biochar amendment than the control in the early and late paddies (p < 0.05), respectively. The abundance of different groups of methanotrophs varied among the treatments. The relative abundance of Methylosarcina was higher for the slag amendment than the control, and the relative abundance of Methylomonas was lower for biochar, and slag + biochar amendments than the control. The relative abundance of Methylocystis was higher for the slag and slag + biochar amendments than the control in the early paddy, and the relative abundance of Methylocystis was higher for the slag, biochar, and slag + biochar amendments in the late paddy. Univariate and multivariate analyses indicated that the higher abundance of methanotrophic bacteria for the slag and slag + biochar amendments was correlated with soil pH, salinity, soil organic carbon, and C/N ratio, and the relative abundances of Methylocystis, Methylomonas, and Methylosarcina were associated with the effective mitigation of CH4 emission in the paddies. A discriminant general analysis indicated that the total population of methanotrophs was larger for the slag + biochar amendment than the control, and that this effect was only weakly correlated with changes in the soil properties, demonstrating that this effect on the size and species composition of methanotrophic soil populations was mostly associated with a direct effect of the slag + biochar amendment.

[Subsequent Effects of Slag and Biochar Application on Greenhouse Gas Emissions from Paddy Fields in the Fuzhou Plain].

We investigate whether slag and biochar applications have subsequent effects on greenhouse gas emissions from paddy fields by applying biochar (B), slag (S), and a biochar-slag mix (BS) to paddy fields in the Fuzhou Plain, China. Applications of the three treatments along with a control (CK) of no amendment were made in 2015 before early and late rice seedlings were transplanted. Two years later in 2017, the CO2, CH4, and N2O emissions in the different treatments and control were measured in the early and late rice growing seasons. The results showed that, in the rice growing season, the averaged CO2 emission in the control, biochar, slag, and mixed applications were (1723.66±194.56), (1245.52±155.05), (1140.29±79.68), and (1055.83±62.13) mg·(m2·h)-1, respectively. The CO2 emissions from the three treatments were significantly lower than the control group (P<0.05), and the reduction ratios of each treatment to the control were 27.74%, 33.84%, and 38.75%, respectively. The averaged CH4 emissions in the control, biochar, slag, and mixed applications were (0.45±0.03), (0.40±0.05), (0.36±0.10), and (0.25±0.04) mg·(m2·h)-1, respectively, which were lower, but not significantly so (P>0.05), than the control. The ratios of CH4 emissions from each treatment to the control were 11.11%, 20.00%, and 44.44%, respectively. The averaged N2O emissions from the control, biochar, slag, and mixed applications were (62.47±27.00), (115.09±30.94), (79.75±24.98), and (112.68±23.59) µg·(m2·h)-1, respectively. In comparison to the control, the biochar, slag, and mixed treatments increased the N2O emissions by 84.23%, 27.66%, and 80.37%, respectively. The global comprehensive warming potential indicated that the application treatments increased the comprehensive warming potential of the early and late rice paddy ecosystems; after 2 years of applying slag and biochar treatments, their effect on the emission reductions were not obvious.

Development of a high-throughput and sensitive assay of fusion genes in lung cancer by array-based MALDI-TOFMS.

ALK (anaplastic lymphoma kinase gene), ROS1 (ros proto-oncogene 1) and RET (ret proto-oncogene) fusions are oncogenic drivers in non-small cell lung cancer (NSCLC). Methods like fluorescence in situ hybridization (FISH) and immunohistochemistry (IHC) are highly sensitive but subjectively analyzed, labor intensive, expensive and unsuitable for multiple fusion gene screening. This study aimed to establish a high-throughput, sensitive and cost-effective screening method (array-based matrix-assisted laser desorption/ionization time-of-flight mass spectrometry, array-based MALDI-TOFMS) for ALK, ROS1 and RET fusion detection. This method was established with three fusion gene positive cell lines (H2228, ALK positive; HCC78, ROS1 positive; LC-2/AD, RET positive) and negative samples. Then, 34 clinical samples were selected and detected by Sanger sequencing, next generation sequencing (NGS) and array-based MALDI-TOFMS. The results were compared and analyzed and Sanger sequencing was considered the standard. 7 cases showed ALK fusions, 1 case showed ROS1 fusions, no case showed RET fusions and 4 cases were both ALK and ROS1 fusions. Results showed that array-based MALDI-TOFMS was 100% concordant with Sanger sequencing and NGS 82.3%. In this study, we reported the utility of array-based MALDI-TOFMS in the assessment of ALK, ROS1 and RET fusions in routine lung biopsies of FFPE and fresh tissue specimens. Besides, this method may also be applied to the diagnosis, monitoring and prognosis of illness.

Europium (III) chelate microparticle-based lateral flow immunoassay strips for rapid and quantitative detection of antibody to hepatitis B core antigen.

Quantitative hepatitis B core antigen (anti-HBc) measurements could play an important role in evaluating therapeutic outcomes and optimizing the antiviral therapy of chronic hepatitis B infection. In this study, we have developed a simple and rapid fluorescence point-of-care test based on a lateral flow immunoassay (LFIA) method integrated with Eu (III) chelate microparticles to quantitatively determine anti-HBc concentrations in serum. This assay is based on a direct competitive immunoassay performed on lateral flow test strips with an assay time of 15 min. The Eu (III) chelate microparticle-based LFIA assay could quantitatively detect anti-HBc levels with a limit of detection of 0.31 IU mL-1, and exhibited a wide linear range (0.63-640 IU mL-1). The intra- and inter-assay coefficients of variation for anti-HBc were both less than 10% and a satisfactory dilution test and accuracy were demonstrated. There were no statistically significant differences in sensitivity or specificity in serum samples between the Eu (III) chelate microparticle-based LFIA strips and the Abbott Architect kit. A simple, rapid and effective quantitative detection of anti-HBc was possible using the Eu (III) chelate microparticle-based LFIA strips. The strips will provide diagnostic value for clinical application.

Comparison of isolation methods of exosomes and exosomal RNA from cell culture medium and serum.

Exosomes are cell-derived vesicles and are abundant in biological fluids; they contain RNA molecules which may serve as potential diagnostic biomarkers in 'precision medicine'. To promote the clinical application of exosomal RNA (exoRNA), many isolation methods must be compared and validated. Exosomes in cell culture medium (CCM) and serum may be isolated using ultracentrifugation (UC), ExoQuick or Total Exosome Isolation Reagent (TEI), and exoRNA may be extracted using TRIzol-LS, SeraMir, Total Exosome RNA Isolation (TER), HiPure Liquid RNA/miRNA kit (HLR), miRNeasy or exoRNeasy. ExoRNA was assessed using NanoDrop, Bioanalyzer 2100, quantitative polymerase chain reaction and high-throughput sequencing. UC showed the lowest recovery of particles, but the highest protein purity for exosome isolation. For isolation of exoRNA, we found that combinations of the TEI and TER methods resulted in high extraction efficiency and purity of small RNA obtained using CCM. High yield and a narrow size distribution pattern of small RNA were shown in exoRNA isolated by exoRNeasy from serum. In RNA profile analysis, the small RNA constituent ratio, miRNA content and amount varied as a result of methodological differences. This study showed that different methods may introduce variations in the concentration, purity and size of exosomes and exoRNA. Herein we discuss the advantages and disadvantages of each method and their application to different materials, therefore providing a reference according to research design.

Interaction of Fe-Mn plaque and Arthrobacter echigonensis MN1405 and uptake and translocation of Cd by Phytolacca acinosa Roxb.

In this study, hydroponic experiments were conducted to investigate the role of Fe-Mn plaque and Arthrobacter echigonensis MN1405 under different solution Cd levels (0, 2 and 50 mg L-1) on Cd uptake and translocation by Phytolacca acinosa Roxb. (P. acinosa). Results showed Cd accumulated by P.acinosa without plaque were mostly distributed in root surface, indicating that an exclusion strategy for Cd tolerance. The formation of Fe-Mn plaque could contribute to the increase in the Cd tolerance of P.acinosa, promotion of the growth, increase in the enhancement of Cd translocation. Among all the treatments, Fe-Mn plaque treatments inoculated with MN1405 accumulated the maximum DCB-Cd (46.61 ± 6.36 g kg-1) and had the highest value of TFaeria (2.14 ± 0.01) at 50 mg L-1 and 2 mg L-1 solution for Cd, respectively, demonstrating the greatest capacity to accumulate and translocate Cd. The uptake of Cd by P. acinosa in plaque treatments may result in the increase of soluble sugar and decrease of soluble protein synthesized from roots which involved in Cd detoxification and thus diminished the negative effects of Cd to some extent.

Dual-Labeled Time-Resolved Immunofluorometric Assay for the Simultaneous Quantitative Detection of Hepatitis B Virus Antigens in Human Serum.

In this paper, a novel time-resolved fluorescence immunoassay (TRFIA) is described that allows the simultaneous quantitative detection of hepatitis B virus surface antigen (HBsAg) and hepatitis B e antigen (HBeAg) in human serum to aid the diagnosis and monitoring of hepatitis B virus infection. The proposed method was developed based on a two-step sandwich immunoassay protocol in which monoclonal antibodies against HBsAg and HBeAg were co-coated in 96 microtitration wells, then tracer polyclonal antibodies against HBsAg labeled with samarium and tracer monoclonal antibodies against HBeAg labeled with europium chelates were used for detection. The detection range was 0.1-150 IU/mL for HBsAg and 0.5-160 PEIU/mL for HBeAg, and the detection limits were 0.03 IU/L and 0.09 PEIU/ml, respectively. The intra- and inter-assay coefficients of variation were below 8 % for both virus antigens. The dilution linearity and accuracy of the assay were satisfactory. No statistically significant differences were observed in sensitivity or specificity for the serum samples between the dual-label TRFIA and a commercial single-label TRFIA. These results demonstrate that an effective, reliable and convenient HBsAg/HBeAg dual-label TRFIA was successfully developed that may be clinically applicable for blood screening to monitor the course of hepatitis B virus infection and predict treatment responses.

Phytolacca acinosa Roxb. with Arthrobacter echigonensis MN1405 enhances heavy metal phytoremediation.

The growth and metal-extraction efficiency of plants when exposed to toxic metals can be enhanced by inoculating with certain bacteria, but the mechanisms of this process remain unclear. We report results from glasshouse experiments on the effect of Arthrobacter echigonensis MN1405 in promoting Phytolacca acinosa Roxb. growth when exposed to 100 mg/L Mn solution. Mn removal efficiency in solution was significantly enhanced by bacterial inoculation; Mn was accumulated in the root of P. acinosa Roxb. plant. The bacteria oxidized the Mn on root surface, which formed a Mn plaque to serve as a barrier or a containment to prevent metal toxicity. In this process, pH condition was an important factor on the effects of microbial-assisted heavy metal phytoremediation. Our finding suggests that A. echigonensis MN1405 assisted P. acinosa to achieve high remediation efficiency of Mn removal and accumulation in Mn contamination area.

A Method to Quantify Cell-Free Fetal DNA Fraction in Maternal Plasma Using Next Generation Sequencing: Its Application in Non-Invasive Prenatal Chromosomal Aneuploidy Detection.

OBJECTIVE: The fraction of circulating cell-free fetal (cff) DNA in maternal plasma is a critical parameter for aneuploidy screening with non-invasive prenatal testing, especially for those samples located in equivocal zones. We developed an approach to quantify cff DNA fractions directly with sequencing data, and increased cff DNAs by optimizing library construction procedure. METHODS: Artificial DNA mixture samples (360), with known cff DNA fractions, were used to develop a method to determine cff DNA fraction through calculating the proportion of Y chromosomal unique reads, with sequencing data generated by Ion Proton. To validate our method, we investigated cff DNA fractions of 2,063 pregnant women with fetuses who were diagnosed as high risk of fetal defects. The z-score was calculated to determine aneuploidies for chromosomes 21, 18 and 13. The relationships between z-score and parameters of pregnancies were also analyzed. To improve cff DNA fractions in our samples, two groups were established as follows: in group A, the large-size DNA fragments were removed, and in group B these were retained, during library construction. RESULTS: A method to determine cff DNA fractions was successfully developed using 360 artificial mixture samples in which cff DNA fractions were known. A strong positive correlation was found between z-score and fetal DNA fraction in the artificial mixture samples of trisomy 21, 18 and 13, as well as in clinical maternal plasma samples. There was a positive correlation between gestational age and the cff DNA fraction in the clinical samples, but no correlation for maternal age. Moreover, increased fetal DNA fractions were found in group A compared to group B. CONCLUSION: A relatively accurate method was developed to determine the cff DNA fraction in maternal plasma. By optimizing, we can improve cff DNA fractions in sequencing samples, which may contribute to improvements in detection rate and reliability.

Biodegradation of tetracycline by the yeast strain Trichosporon mycotoxinivorans XPY-10.

We investigated the behavior of tetracycline degradation and its degradation products upon treatment of isolated yeast that we termed "XPY-10." XPY-10 was isolated from wastewater and identified as Trichosporon mycotoxinivorans by morphological and physiological tests and 5.8S rRNA ITS sequencing. In our experiments, 78.28 ± 0.8% of tetracycline was removed within 7 days with XPY-10. The degradation of tetracycline fitted well with the first-order kinetic model. We also speculated upon the biodegradation products formed during biodegradation. The possible structures of five products were determined using liquid chromatography-tandem mass spectrometry. During practical application, XPY-10 was shown to have an obvious influence on biodegradation, and 89.61% of tetracycline was removed in feedlot sewage after 7 days of reaction. The chemical oxygen demand removal reached 73.47%.

Rapid and sensitive lateral flow immunoassay method for determining alpha fetoprotein in serum using europium (III) chelate microparticles-based lateral flow test strips.

Alpha-fetoprotein (AFP), a primary marker for many diseases including various cancers, is important in clinical tumor diagnosis and antenatal screening. Most immunoassays provide high sensitivity and accuracy for determining AFP, but they are expensive, often complex, time-consuming procedures. A simple and rapid point-of-care system that integrates Eu (III) chelate microparticles with lateral flow immunoassay (LFIA) has been developed to determine AFP in serum with an assay time of 15 min. The approach is based on a sandwich immunoassay performed on lateral flow test strips. A fluorescence strip reader was used to measure the fluorescence peak heights of the test line (HT) and the control line (HC); the HT/HC ratio was used for quantitation. The Eu (III) chelate microparticles-based LFIA assay exhibited a wide linear range (1.0-1000 IU mL(-1)) for AFP with a low limit of detection (0.1 IU mL(-1)) based on 5ul of serum. Satisfactory specificity and accuracy were demonstrated and the intra- and inter-assay coefficients of variation (CV) for AFP were both <10%. Furthermore, in the analysis of human serum samples, excellent correlation (n = 284, r = 0.9860, p < 0.0001) was obtained between the proposed method and a commercially available CLIA kit. Results indicated that the Eu (III) chelate microparticles-based LFIA system provided a rapid, sensitive and reliable method for determining AFP in serum, indicating that it would be suitable for development in point-of-care testing.

Inhibition or promotion of biodegradation of nitrate by Paracoccus sp. in the presence of nanoscale zero-valent iron.

To investigate the effect of nanoscale zero-valent iron (nZVI) on the growth of Paracoccus sp. strain and biodenitrification under aerobic conditions, specific factors were studied, pH, concentration of nitrate, Fe (II) and carbon dioxide. Low concentration of nZVI (50mg/L) promoted both cell growth and biodegradation of nitrate which rose from 69.91% to 76.16%, while nitrate removal fell to 67.10% in the presence of high nZVI concentration (1000 mg/L). This may be attributed to the ions produced in nZVI corrosion being used as an electron source for the biodegradation of nitrate. However, the excess uptake of Fe (II) causes oxidative damage to the cells. To confirm this, nitrate was completely removed after 20 h when 100mg/L Fe (II) was added to the solution, which is much faster than the control (86.05%, without adding Fe (II)). However, nitrate removal reached only 45.64% after 20 h, with low cell density (OD 600=0.62) in the presence of 300 mg/L Fe (II). Characterization techniques indicated that nZVI adhered to microorganism cell membranes. These findings confirmed that nZVI could affect the activity of the strain and consequently change the biodenitrification.

[Isolation and characterization of the salt-tolerant aerobic denitrifying bacterial strain A-13].

OBJECTIVE: This study is aimed to isolate and identify an aerobic denitrifying bacterium with high ability for nitrogen removing, and optimize its growing and denitrifying conditions to obtain the theory basis for controlling the eutrophic artificial lake. METHODS: Aerobic denitrifying bacterium strain A-13 was screened by denitrifying medium. Strain identification was carried out through morphological, biochemical and physiological characteristics, 16S rRNA gene and periplasm nitrate reductase gene analysis. The optimal pH, temperature, carbon source, dissolved oxygen (DO), inoculum ratio were tested as well. RESULTS: Strain A-13 isolated from a drain outlet located in Gaoqi village, Shangjie town, Minhou county, Fuzhou, China, was a member of Pseudomonas stutzeri and its DNA sequence was most closely related to Pseudomonas stutzeri DSM 50283. The optimal conditions for its growth and denitrification were followed as: pH 6.5, 33 degrees C, 150 r/min, 5% inoculum rate and the best carbon source was sodium succinate. Under these conditions, the maximum removal capacity for NO3- was approximately 1900 mg/L. The strain could grow well in the medium with high salinity (10%) and could also use NO2- and NH(4+)-H as the sole nitrogen source. CONCLUSION: The isolated P. stutzeri, A-13 is a potential strain to treat wastewater with high salinity and/or eutrophication.

Biosorption of Cd(II) from aqueous solution by Pseudomonas plecoglossicida: kinetics and mechanism.

In our present study, we investigated the mechanism of Cd(II) biosorption from aqueous solution by Pseudomonas plecoglossicida using different instrumental techniques. The adsorption kinetics fitted well with the pseudo second-order model, suggesting that the Cd(II) adsorption by P. plecoglossicida consisted of a chemisorption and a physisorption process. Compared with the dead P. plecoglossicida cells, the live cells demonstrated the same adsorption capacity of Cd(II). Scanning electron microscope with energy dispersive X-ray spectroscopy analysis revealed that the main mechanism of adsorption was the combination of Cd(II) with the organic functional groups in the cell wall of P. plecoglossicida. Furthermore, Fourier transform infrared spectroscopic analysis of the metal-loaded biosorbent confirmed the participation of -NH, -OH, -CH, and -CONH groups in the uptake of Cd(II). Moreover, cation transport test revealed that ionic exchange interactions were involved in the Cd(II) adsorption. However, it only played a minor role in the Cd(II) biosorption process.

miRNA regulatory circuits in ES cells differentiation: a chemical kinetics modeling approach.

MicroRNAs (miRNAs) play an important role in gene regulation for Embryonic Stem cells (ES cells), where they either down-regulate target mRNA genes by degradation or repress protein expression of these mRNA genes by inhibiting translation. Well known tables TargetScan and miRanda may predict quite long lists of potential miRNAs inhibitors for each mRNA gene, and one of our goals was to strongly narrow down the list of mRNA targets potentially repressed by a known large list of 400 miRNAs. Our paper focuses on algorithmic analysis of ES cells microarray data to reliably detect repressive interactions between miRNAs and mRNAs. We model, by chemical kinetics equations, the interaction architectures implementing the two basic silencing processes of miRNAs, namely "direct degradation" or "translation inhibition" of targeted mRNAs. For each pair (M,G) of potentially interacting miRMA gene M and mRNA gene G, we parameterize our associated kinetic equations by optimizing their fit with microarray data. When this fit is high enough, we validate the pair (M,G) as a highly probable repressive interaction. This approach leads to the computation of a highly selective and drastically reduced list of repressive pairs (M,G) involved in ES cells differentiation.