Characteristics and catalytic mechanism of a novel multifunctional oxidase, CpmO, for chloramphenicols degradation from Sphingobium sp. WTD-1.

Chloramphenicols (CAPs) are ubiquitous emerging pollutants that threaten ecological environments and human health. Microbial and enzyme-based biodegradation strategies offer a cost-effective environmentally friendly approach for CAPs removal from contaminated sites. Here, CpmO, a novel multifunctional oxidase for CAP degradation was identified from the CAP-degrading strain Sphingobium sp. WTD-1. This enzyme was found to be responsible for both the oxidation of the C3-hydroxyl and oxidative cleavage of the C1-C2 bond of CAP, and the oxidative cleavage pathway of CAP was dominant. The catalytic efficiency of CpmO for CAP was 41.6 times that for thiamphenicol (TAP) under the optimal conditions (40 °C, pH 6.0). CpmO was identified as a member of the glucose-methanol-choline oxidoreductase family. Molecular docking and site-directed mutagenesis analysis indicated that CAP was connected to the key amino acid residues E231/E395, K277, and I273/A276 in CpmO through hydrogen bonding, nonclassical hydrogen bonding, and π-π stacking forces, respectively. The catalytic activities of the A276W, K277P, and E231S mutants were found to be 1.1 times, 6.4 times, and 13.2 times higher than that of the wild type, respectively. These findings provide genetic resources and theoretical guidance for future application in biotechnological and metabolic engineering efforts for the remediation of CAPs-contaminated environments.

Innovative accumulative risk assessment strategy of co-exposure of As and Pb in medical earthworms based on in vivo-in vitro correlation.

Recent studies on risks assessment of heavy metal(loid) are usually based on their total concentrations. Nevertheless, such an analysis does not assess their real amounts absorbed by human body. To scientifically assess the health risks, in this study medical earthworms were analyzed for relative bioavailability (RBA) of arsenic (As) and lead (Pb) using a multiple gavage mouse model with liver, kidneys, brain, and leg bones as biomarkers for the first time. Metal(loid) bioaccessibility was determined using in vitro physiologically based extraction (PBET) assay. We are the first to develop a novel accumulative health risk assessment strategy by combinational analyzing bioavailability of heavy metal(loid) levels to calculate target organ toxicity dose (TTD) modification of the HI and total cancer risk (TCR), which has capacity to evaluate the health risks of co-exposure of Pb and As in medical earthworms. As a result, As-RBA ranged from 7.2% to 45.1%, and Pb-RBA ranged from 16.1% to 49.8%. Additionally, As and Pb bioaccessibility varied from 6.7% to 48.3% and 7.8% to 52.5%, respectively. Moreover, strong in vivo-in vitro correlations (IVIVCs) were observed between metal-RBA and bioaccessibility, indicating the robustness of the in vitro PBET assay to predict metal-RBA in medical earthworms. The refined accumulative assessment strategy revealed that when adjusted by heavy metal(loid) bioavailability, the TTD modification of HI method typically exhibited an acceptable health risk caused by the co-exposure of Pb and As for cardiovascular, hematological, neurological, and renal system. The TCR levels associated with exposure to Pb and As due to the ingestion of medical earthworms were also acceptable after adjustment by bioavailability. Collectively, our innovation on accumulative risk assessment based on in vivo-in vitro correlation provides a novel approach engaging in assessing the risks due to co-exposure of As and Pb in medical earthworms.

Aggregation of konjac glucomannan by ethanol under low-alkali treatment.

Utilizing ethanol in konjac glucomannan (KGM) gelation has important food processing applications. Typically, ethanol positively impacts the formation of low-alkali KGM gels and dramatically changes their physical properties, but the role of ethanol on the aggregation of KGM chains and the resultant gelation is less well understood. This study presents the distinct microstructures of low-alkali KGM gels incorporating ethanol. The fibril diameter and mesh size were determined to be 262.3 ± 22.3 nm and 2.680 ± 0.035 µm in average, contributing to a higher degree of anisotropy of such a gel network. Ethanol favors intermolecular aggregation by increasing the Rg of small-sized aggregates to 2.10 nm. The FTIR and temperature-cycled rheological studies suggest there are hydrophobic interactions stabilizing the gel network with the assistance of hydrogen bonds. The spatial confinement of deacetylated KGM chains as the solvent quality deteriorates by incorporating ethanol may arrange the aggregation and induce the structural reorganization in gel formation.

Total Flavonoids of Drynariae Rhizoma Improve Glucocorticoid-Induced Osteoporosis of Rats: UHPLC-MS-Based Qualitative Analysis, Network Pharmacology Strategy and Pharmacodynamic Validation.

Background: Glucocorticoid-induced osteoporosis (GIOP) is a common form of secondary osteoporosis caused by the protracted or a large dosage of glucocorticoids (GCs). Total flavonoids of Drynariae rhizoma (TFDR) have been widely used in treating postmenopausal osteoporosis (POP). However, their therapeutic effects and potential mechanism against GIOP have not been fully elucidated. Methods: Ultra-high-performance liquid chromatography coupled with electrospray ionization quadrupole time-of-flight mass spectrometry (UHPLC-ESIQ-TOF-MS) experiments were performed for qualitative analysis. We performed hematoxylin-eosin (HE) staining and microcomputed tomography (micro-CT) analysis to detect the changes in bone microstructure. The changes in biochemical parameters in the serum samples were determined by performing an enzyme-linked immunosorbent assay (ELISA). The prediction results of network pharmacology were verified via quantitative real-time polymerase chain reaction (qRT-PCR) to elucidate the potential mechanism of TFDR against GIOP. Results: A total of 191 ingredients were identified in vitro and 48 ingredients in vivo. In the in-vivo experiment, the levels of the serum total cholesterol (TC), the serum triglyceride (TG), Leptin (LEP), osteocalcin (OC), osteoprotegerin (OPG), bone morphogenetic protein-2 (BMP-2), propeptide of type I procollagen (PINP), tartrate-resistant acid phosphatase (TRACP) and type-I collagen carboxy-terminal peptide (CTX-1) in the TFDR group significantly changed compared with those in the GIOP group. Moreover, the TFDR group showed an improvement in bone mineral density and bone microstructure. Based on the results of network pharmacology analysis, 67 core targets were selected to construct the network and perform PPI analysis as well as biological enrichment analysis. Five of the targets with high "degree value" had differential gene expression between groups using qRT-PCR. Conclusion: TFDR, which may play a crucial role between adipose metabolism and bone metabolism, may be a novel remedy for the prevention and clinical treatment of GIOP.

Linear and non-linear rheological properties of water-ethanol hybrid pectin gels for aroma enhancement.

Whereas water-ethanol hybrid gels present an opportunity to realize aroma enhancement, translating hypothesis into practice is limited by poorly defined viscoelastic characteristics of those gels. In this work, the linear and non-linear rheological properties of water-ethanol hybrid pectin gels (WEPGs) were studied. Those WEPGs are physical gels in nature and the WEPG of 28.6% v/v ethanol differs basically from those of higher ethanol concentrations in the gel strength, resistance to deformation and non-linear properties. The retention of isopentyl acetate of WEPGs is dramatically improved by increasing the ethanol concentration to 33.3% v/v in the co-solvent system, but it is not further improved at 37.5% v/v. The cluster analysis reveals strong positive correlations between the isopentyl acetate release concentration and v 3/v 1 and absolute value of S/T ratio under 100% strain, suggesting the non-linear rheological responses of WEPGs have to be taken into account for which the enhancement of aroma is desired.

Analysis of longitudinal coupling dynamic characteristics of deep sea mining vessel and stepped lifting pipe.

In deep-sea mining, the coupling dynamic response between the mining vessel and the lifting pipe is a significant problem, which directly affects the structural design of the lifting system and the safety of field operation. The characteristics of coupled motion model have not been fully considered in the existing research. Therefore, this paper uses time-domain coupled numerical model as the research object, considering ocean current, surface wave, pipe dynamics and vessel-pipe contact mechanics, to study the dynamic behavior of the lifting pipe and mining vessel during the process of deep-sea mining using AQWA and OrcaFlex softwares. The response amplitude operator (RAO) is used to compare the measured and simulations dynamic response of the mining vessel. There is a very good agreement in RAO between the experiments and simulations. The coupling simulation results show that the coupling effect has a significant effect on the time domain dynamic response of the lifting pipe, but has little effect on the average effective tension and longitudinal amplitude along the pipe length. The research results of this paper are of great significance to the safety design of deep-sea mining lifting system and the planning of deep-sea operation activities.

Longitudinal vibration compensation model of stepped-pipe strings in deep-sea mining.

In this paper, the dynamic model of the rigid space stepped-pipe strings system is derived with Lagrangian method to represent the system dynamic behaviors which enriches the analysis method of longitudinal vibration of stepped-pipe strings. The stepped-pipe strings is constructed of pipes with different diameters and lengths, the physical properties of which mainly depends on the axial force and the depth of deep-sea mining. Based on lumped element method, the heave compensation system with dynamic vibration absorber is designed for longitudinal vibration suppression of the stepped-pipe strings. The analytical solution is obtained by modal analysis method when the mining ship is subjected to sea breeze excitation. The proposed method is easily implementable for rigid space stepped-pipe strings system with complex multi-degree-of-free deep-sea mining dynamic model. Furthermore, the optimal combination of mass ratio, spring coefficient and damping ratio is shown to have a better vibration suppression performance. Finally, numerical simulations on the stepped-pipe strings system with or without dynamic vibration absorbers are provided to demonstrate the effectiveness of the proposed method.

Rule-based expert system to assess caving output ratio in top coal caving.

Coal mining professionals in coal mining have recognized that the assessment of top coal release rate can not only improve the recovery rate of top coal, but also improve the quality of coal. But the process was often performed using a manual-based operation mode, which intensifies workload and difficulty, and is at risk of human errors. The study designs a assessment system to give the caving output ratio in top coal caving as accurately as possible based on the parameters adaptive Takagi-Sugeno (T-S) fuzzy system and the Levenberg-Marquardt (LM) algorithm. The main goal of the adaptive parameters based on LM algorithm is to construct its damping factor in the light of lowering of the objective function which is as taken as the index of termination iteration. The performance of the system is evaluated by Pearson correlation coefficient, Coefficient of Determination and relative error where the results of the Takagi-Sugeno method and the parameters adaptive Takagi-Sugeno method are compared to make the evaluation more robust and comprehensive.

Combination of minimum enclosing balls classifier with SVM in coal-rock recognition.

Top-coal caving technology is a productive and efficient method in modern mechanized coal mining, the study of coal-rock recognition is key to realizing automation in comprehensive mechanized coal mining. In this paper we propose a new discriminant analysis framework for coal-rock recognition. In the framework, a data acquisition model with vibration and acoustic signals is designed and the caving dataset with 10 feature variables and three classes is got. And the perfect combination of feature variables can be automatically decided by using the multi-class F-score (MF-Score) feature selection. In terms of nonlinear mapping in real-world optimization problem, an effective minimum enclosing ball (MEB) algorithm plus Support vector machine (SVM) is proposed for rapid detection of coal-rock in the caving process. In particular, we illustrate how to construct MEB-SVM classifier in coal-rock recognition which exhibit inherently complex distribution data. The proposed method is examined on UCI data sets and the caving dataset, and compared with some new excellent SVM classifiers. We conduct experiments with accuracy and Friedman test for comparison of more classifiers over multiple on the UCI data sets. Experimental results demonstrate that the proposed algorithm has good robustness and generalization ability. The results of experiments on the caving dataset show the better performance which leads to a promising feature selection and multi-class recognition in coal-rock recognition.

[Preliminary study of intervention in effect of Bushen Huoxue recipe on calcification of lumbar vertebra cartilage endplate of the aging gerbils].

OBJECTIVE: To study the effect of Bushen Huoxue decoction on calcification of cartilage endplate in lumbar vertebrae. METHODS: Six healthy male gerbils with 2-month-old were selected as normal control group, and 24 7-month-old healthy male gerbils were fed to 12-month-old to establish the aged gerbil model. Thirty gerbils were randomly divided into five groups as follow: the normal control group (n=6), model group (n=6, normal saline 4 ml/kg, intragastric 30 d), Bushen Huoxue low dose group(n=6, 1.9× 10⁻ ³ ml/g given Bushen Huoxue recipe orally, 30 d), Bushen Huoxue middle dose group(n=6, 3.8× 10⁻ ³ ml/g given Bushen Huoxue recipe orally, 30 d), Bushen Huoxue high dose group(n=6, 7.6× 10⁻ ³ ml/g given Bushen Huoxue recipe orally, 30 d), the intervention group administered for 1.36 g from 7-month-old age, 30 d. The animals were sacrificed at the age of 2 months in the normal control group and 12 months of age in the other groups. The morphology of the lumbar vertebral cartilage endplate, the area of vascular bud, the ratio of non-calcified/calcified layer were analysis by HE chromosome visual method. The expression of type X collagen and BMPs in cartilage endplates were detected by rabbit monoclonal immunohistochemical staining. RESULTS: The relative area of the vascular buds cartilage endplate measurements showed that compared with the model group, middle dose group and normal control group increased (P<0.05), high and low dose groups all had different degrees of increase, but no statistical significance(P>0.05). The ratio of cartilage endplate thickness of non-calcified/calcified showed that compared with the model group, Bushen Huoxue middle dose, normal control group increased, with statistical significance(P<0.05), and high and low dose groups all had different degrees of increase, but there were no statistical significance(P>0.05). Compared with the model group, the expression of type X collagen in the cartilage endplate of the normal group, the Bushen Huoxue low, middle and high dose groups decreased, and had statistical significance(P<0.01); compared with the model group, the expression of BMPs in the normal group, Bushen Huoxue middle dose group increased, with statistically significant(P<0.01), while the high and low dose groups increased in different degrees, but there was no statistical significance(P>0.05). CONCLUSIONS: Bushen Huoxue prescription can delay the calcification of cartilage endplate in the process of aging, suggesting that it can be used as a preventive medicine for early disc degeneration.

[FTIR microspectroscopic investigation of the age-related changes of subchondral bone of the knee in guinea pig].

Fourier transform infrared (FTIR) microspectroscopy was applied to in-situ analyse the chemical change of tibial articular subchondral bone of female Hartley guinea pigs with age increase. Three infrared absorption regions (a, b, c) of trabecular bone and central marrow region of the subchondral bone were measured for guinea pigs of different ages (1 months, 2 months and 3 months) using the infrared spectrum. Results show that (1) with months increasing, the total area of trabecular bone is increasing, meanwhile, the region a which is similar to normal trabecular bone spectra is decreasing, and region d waveform has the same trend as region a. (2) In the second and third month, region b & c show amide Ill redshift and the red shift in region c shows a shoulder peak, showing the absorption peak intensity on behalf of nucleic acid and polysaccharide in region b & c is 7 times that in region a. (3) beta glycosidic bond absorption peak appears at region c in 3 different old pigs. (4) I(amide III) / I(amide II) is the highest in region b in the second month but lowest in the third month; I(amide III) / I(amide II) reduces from a to c in the second and third month; I(upsilon3)PO2- / I(amide II) in region b & c is 7 times higher than region a in the second and third Month These results are consistent with the regular pattern of change rule of osteoarthritis subchondral bone's organization structure and chemical composition in different stages. Our primary result illustrated that FTIR microspectroscopy can be used for in-situ analysis of the molecular organization of subchondral trabecular bone and bone marrow. It provides reliable pathology information for osteoarthritis subchondral bone tissue at molecular level.

[Preliminary investigation of animal model of tibial defection fracture made by drilling hole method ].

OBJECTIVE: To compare the differences in damage degree, healing time and healing process between two animal models of defection fracture and provide the research data for the establishment of a new animal model. METHODS: Sixty male SPF Spragur-Dawley rats were divided randomly into control group, sawing group and drilling hole group, with 20 rats in each group. Animals of drilling hole group were treated with hone drill and made an 1 mm hole on tibial plateau animals of sawing group were treated with saw and made an 3 mm defection on tibial plateau; nothing to do in animals of control group. The rats were respectively killed at 2nd, 4th weeks after operation, bone density, bone ash quantity, contents of bone Ca, P were detected. RESULTS: At the 2nd week after operation, bone density, bone ash quantity, contents of bone Ca, P in drilling hole group and sawing group were significantly lower than that of the control group (P < 0.05 or P < 0.01). Two animal models of drilling hole group and sawing group were similar in X-ray films and pathology investigations. At the 4th week after operation, there were no significant defference in bone density and bone ash quantity among three groups (P > 0.05). Rats of sawing group showed more poroma and inflammatory infiltration in histological examination. CONCLUSION: Drilling hole method and sawing method could be used to make animal model of defection fracture, two methods showed similar damage degree, healing time and healing process, hut drilling hole method have advantages of simple operation, easily control damage degree and less inflammatory infiltration and bone disunion.

[Investigation of articular cartilage using FTIR microspectroscopy for guinea pig with spontaneous osteoarthritis].

In-situ analysis the chemical composition of tibial articular cartilage of female Hartley guinea pigs with Fourier transform infrared (FTIR) microspectroscopy was conducted. The infrared spectrum survey consists of three ages (1 months, 2 months and 3 months) and three cartilage layers (surface, middle and deep). The results demonstrated that with ages increasing, the peak positions of main absorbance bands in surface and middle shifted to a lower wavenumber, and in deep they shifted to a lower wavenumber first, then shifted to a higher wavenumber. Infrared spectrum character of collagen, nucleic acid and proteoglycan were compared and analyzed. The ratios of I1 657/I 1 548, I1 074/I1 548 and I1 074/I1 237 tend to decrease with ages increasing in surface and middle. However, the ratios at 2 months are less than other ages in deep. These results are consistent with the regular pattern of cartilage ingredient change in different degradation stage, while the tibial platform images created by microscopic spectral imaging technology is highly compliant with pathology description. The authors' primary result illustrated that FTIR microspectroscopy can be used for in-situ analysis of molecular constituents of different levels cartilages. The molecular information obtained from the study is important for understanding the pathogenesis of cartilage diseases.