Differences in the properties of extracellular polymeric substances responsible for PAH degradation isolated from Mycobacterium gilvum SN12 grown on pyrene and benzo[a]pyrene.

This study aimed to evaluate the differences in the characteristics of extracellular polymeric substances (EPSs) secreted by Mycobacterium gilvum SN12 (M.g. SN12) cultured on pyrene (Pyr) and benzo[a]pyrene (BaP). A heating method was used to extract EPSs from M.g. SN12, and the composition, emulsifying activity, and morphology of EPS extracts were investigated. Results showed that EPS extracts varied significantly with Pyr or BaP addition to the bacterial cultures. The concentration of proteins and carbohydrates, the main components of the EPS extracts, first increased and then decreased, with an increase in the concentration of Pyr (0-120 mg L-1) and BaP (0-120 mg L-1). A similar trend was observed for the emulsifying activity of the EPS extracts. EPSs extracted from all cultures exhibited a compact structure with a smooth surface, except for EPSs extracted from BaP-grown M.g. SN12, which revealed a more fragile and softer surface. These findings suggest that Pyr and BaP had different influences on the properties of isolated EPSs, providing insights into the mechanism underlying polycyclic aromatic hydrocarbons (PAHs) biodegradation by some EPS-secreting bacteria. To the best of our knowledge, this is the first report on the texture profile of EPS samples extracted from M.g. SN12 grown on PAHs.

Application of pedicled greater omentum flap tamponade combined with laparoscopic fenestration in diaphragmatic hepatic cyst.

OBJECTIVE: To investigate the efficacy and clinical application advantage of omental tamponade with vascular pedicle combined with Laparoscopic fenestration for the treatment of diaphragmatic hepatic cyst. METHODS: A total of 56 patients with diaphragmatic hepatic cysts underwent laparoscopic surgery in a single tertiary academic medical center from January 2010 to October 2020, including 21 patients (non-omental group) underwent laparoscopic fenestration of liver cysts, and 36 patients underwent laparoscopic liver cyst fenestration combined with vascular pedicle omentum tamponade (omental group). The general conditions and follow-up results of the two groups were compared and annalyzed. RESULTS: The operation time of the omental group was longer than that of the non-omental group (P = 1.358E-4). There was no significant difference in postoperative complications, postoperative laboratory values and hospital costs (P>0.05). The length of hospital stay in omental group was shorter than that in non-omental group (P = 0.034). In the omental group, recurrence occurred in 1 of 35 patients (4.65%) who were followeded up 12 months after surgery. In the non-omental group, of the 21 patients followed, 3 patients (14.28%) recurred 6 months after surgery, and 8 patients (38.10%) recurred 12 months after surgery. CONCLUSION: It is an effective method to prevent the recurrence of diaphragmatic hepatic cyst after laparoscopic fenestration by packing the cyst with vascularized omentum.

Rapid diagnosis of sepsis with TaqMan-Based multiplex real-time PCR.

BACKGROUND: The survival rate of septic patients mainly depends on a rapid and reliable diagnosis. A rapid, broad range, specific and sensitive quantitative diagnostic test is the urgent need. Thus, we developed a TaqMan-Based Multiplex real-time PCR assays to identify bloodstream pathogens within a few hours. METHODS: Primers and TaqMan probes were designed to be complementary to conserved regions in the 16S rDNA gene of different kinds of bacteria. To evaluate accurately, sensitively, and specifically, the known bacteria samples (Standard strains, whole blood samples) are determined by TaqMan-Based Multiplex real-time PCR. In addition, 30 blood samples taken from patients with clinical symptoms of sepsis were tested by TaqMan-Based Multiplex real-time PCR and blood culture. RESULTS: The mean frequency of positive for Multiplex real-time PCR was 96% at a concentration of 100 CFU/mL, and it was 100% at a concentration greater than 1000 CFU/mL. All the known blood samples and Standard strains were detected positively by TaqMan-Based Multiplex PCR, no PCR products were detected when DNAs from other bacterium were used in the multiplex assay. Among the 30 patients with clinical symptoms of sepsis, 18 patients were confirmed positive by Multiplex real-time PCR and seven patients were confirmed positive by blood culture. CONCLUSION: TaqMan-Based Multiplex real-time PCR assay with highly sensitivity, specificity and broad detection range, is a rapid and accurate method in the detection of bacterial pathogens of sepsis and should have a promising usage in the diagnosis of sepsis.

A study of the kinetics and isotherms for Cr(VI) adsorption in a binary mixture of Cr(VI)-Ni(II) using hierarchical porous carbon obtained from pig bone.

Cr(VI) adsorption in a binary mixture Cr(VI)-Ni(II) using the hierarchical porous carbon prepared from pig bone (HPC) was investigated. The various factors affecting adsorption of Cr(VI) ions from aqueous solutions such as initial concentration, pH, temperature and contact time were analyzed. The results showed excellent efficiency of Cr(VI) adsorption by HPC. The kinetics and isotherms for Cr(VI) adsorption from a binary mixture Cr(VI)-Ni(II) by HPC were studied. The adsorption equilibrium described by the Langmuir isotherm model is better than that described by the Freundlich isotherm model for the binary mixture in this study. The maximum adsorption capacity was reliably found to be as high as 192.68 mg/g in the binary mixture at pH 2. On fitting the experimental data to both pseudo-first- and second-order equations, the regression analysis of the second-order equation gave a better R² value.

Study on characterization of Bupleurum chinense polysaccharides with antioxidant mechanisms focus on ROS relative signaling pathways and anti-aging evaluation in vivo model.

This study explored the structures of three polysaccharides from Bupleurum chinense DC. (BCPRs), and evaluated their antioxidant and anti-aging properties. The HPGPC and ion chromatography analyses revealed that the molecular weights of the BCPRs ranged from 12.05 to 21.20 kDa, and were primarily composed of rhamnose, arabinose, xylose, galactose, glucose and galacturonic acid. Methylation and NMR studies identified 10 PMAAs, establishing the various backbones of BCPRs 1-3. BCPR-3 demonstrated potent antioxidant activities, including DPPH, ABTS, hydroxy, and superoxide radicals scavenging in vitro. At concentrations between 125 and 500 µg/mL, BCPR-3 increased T-AOC, SOD and GSH-Px activities, while decreasing MDA levels in H2O2-induced SH-SY5Y cells. In addition, RNA-seq results indicated that BCPR-3 considerably downregulated the expression of 49 genes and upregulated five genes compared with the control group. KEGG analysis suggested that these differentially expressed genes (DEGs) were predominantly involved in the TNF and PI3K/Akt signaling pathways. Furthermore, in vivo experiment with Drosophila melanogaster showed that BCPR-3 could extend the average lifespan of flies. In conclusion, polysaccharides from B. chinense exhibited potential antioxidant and anti-aging activities, which could be developed as new ingredients to combat oxidative stress damage and slow the aging process.

Effect of huanglianjiedu tang on fever in rats induced by 2, 4-dinitrophenol.

OBJECTIVE: To study metabolic characteristics of fever in rats induced by 2, 4-dinitrophenol (DNP) and the effect of Huanglianjiedu Tang (HLJDT) on the fever. METHODS: The urine samples were analyzed by ultra-performance liquid chromatography/electrospray ionization quadruple time-of-flight mass spectrometry (UPLC/ESI-Q-TOF-MS) at the positive ion mode scanning, and experimental data were analyzed by the principal component analysis. RESULTS: Eight potential biomarkers indicating the occurrence and evolvement of fever were determined according to ions in urine samples. Five of them were found increased, while the other three decreased. After HLJDD intervention, the increased five were reduced significantly in high dose group, compared with model group, while the decreased three had no obvious change. Five of the eight biomakers were identified with formyl-5-hydroxykynurenamine, gentisic acid, aminoadipic acid, phenylacetic acid, L-phenylalanyl-L-hydroxyproline on the basis of MS/MS. These biomarkers are associated with the metabolism of 5-hydroxytryptamine, tyrosine, lysine, phenylalanine and collagen protein, respectively. CONCLUSION: HLJDT had significant effect on DNP-induced fever in rats. The effect was performed possibly by acting on 5-hydroxytryptamine in hypothalamus and some amino acid metabolism. These results suggested that HLJDT relieved fever by acting on multi-targets.

CircPSMC3 Inhibits Colorectal Cancer Cell Growth and Migration by Controlling miR-31-5p/YAP/ß-Catenin.

INTRODUCTION: Colorectal cancer (CRC) is hackneyed cancer and a major lethiferous cancer. Circular RNAs (CircRNAs) have been discovered to own important roles in controlling CRC progression. CircPSMC3 is known to exhibit lower expression in diversified cancers. However, the regulatory function of CircPSMC3 in CRC keeps unclear. METHODS: The expression of CircPSMC3 and miR-31-5p was confirmed through RT-qPCR. The cell proliferation was measured through CCK-8 and EdU assays. The protein expression of genes was examined through a western blot. The cell invasion and migration were tested through Transwell and wound healing assays. The binding ability between CircPSMC3 and miR-31-5p was confirmed through the luciferase reporter assay. RESULTS: CircPSMC3 exhibited lower expression in CRC tissues and cell lines. Additionally, CircPSMC3 was revealed to suppress cell proliferation in CRC. Moreover, through Transwell and wound healing assays, CircPSMC3 was discovered to repress CRC cell invasion and migration. In CRC tissues, miR-31-5p expression was up-regulated and negatively correlated with CircPSMC3 expression. Further mechanism exploration experiments disclosed that CircPSMC3 is bound with miR-31-5p to modulate the YAP/ß-catenin axis in CRC. At last, through rescue assays, CircPSMC3 inhibited cell proliferation, invasion and migration through sponging miR-31-5p in CRC. CONCLUSION: Our work was the first time to probe the potential regulatory effects of CircPSMC3 in CRC, and these above results uncovered that CircPSMC3 inhibited CRC cell growth and migration through regulating miR-31-5p/YAP/ß-catenin. This discovery hinted that CircPSMC3 may serve as a useful therapeutic candidate for CRC.

Corrigendum: A minimally manipulated preservation and virus inactivation method for amnion/chorion.

[This corrects the article DOI: 10.3389/fbioe.2022.952498.].

A novel bacteriophage KSL-1 of 2-Keto-gluconic acid producer Pseudomonas fluorescens K1005: isolation, characterization and its remedial action.

BACKGROUND: Bacteriophages have the destructive damage on the industrial bioprocess. 2-Keto-gluconic acid (2KGA) producing bacteria had also been attacked and lysed by bacteriophages which lowered the glucose consumption and 2KGA yield and even stopped the fermentation process. In this study, we presented the characteristics of a novel virulent bacteriophage specifically infecting Pseudomonas fluorescens K1005 and proposed an efficient remedial action for this phage infection to reduce the production loss. RESULTS: The phage KSL-1 of Pseudomonas fluorescens K1005 was isolated from abnormal 2KGA fermentation broth. It belonged to the Siphoviridae family with a hexagonal head diameter of about 99 nm and a non-contractile tail of about 103 nm × 39 nm. The genome size of phage KSL-1 was estimated to be approximately 53 kbp. Its optimal MOI to infect P. fluorescens K1005 was about 0.001. One-step growth curve gave its latent and burst periods of 90 min and 75 min with a burst size of 52 phage particles per infected cell. This phage was stable with a pH range of 7.0-10.0, and sensitive to thermal treatment. Finally, a simple remedial action was proposed by feeding fresh seed culture. Compared with the infected 2KGA fermentation, the remedial experiments restored 2KGA fermentation performance by increasing the produced 2KGA concentration to 159.89 g/L and shortening the total fermentation time of 80 h with the productivity and yield of 2.0 g/L.h and 0.89 g/g. The obtained data proved that this method was effective to combat the phage infections problems during the 2KGA fermentation. CONCLUSION: The phage KSL-1 was a novel bacteriophage specifically infecting Pseudomonas fluorescens K1005. The remedial action of feeding fresh seed culture to the infected broth was an easily-operating and effective method to maintain a high 2KGA yield and avoid the draft of infected broth.

Influences of impervious surfaces on ecological risks and controlling strategies in rapidly urbanizing regions.

Reducing ecological risks is important for promoting regional sustainable development. However, studies on the influence of impervious surfaces on ecological risks and risk control strategies in regions undergoing rapid urbanization are limited. Therefore, this study aimed to demonstrate the spatial-temporal dynamics of regional ecological risks using Beijing as a case study to reveal the influence of impervious surfaces and explore the controlling strategies of risks. We first characterized the ecological risks in Beijing based on the ecosystem service values and mapped the risk levels and temporal variations in risks. We then identified the ecological risk increases caused by impervious surface expansion and built linear regression models for impervious surface coverage (ISC) and risk index. Finally, we formulated ecological risk control strategies for the strategy categories identified based on the ISC thresholds. The results show that the mountainous areas mainly exhibited low ecological risk levels, and the plain areas mainly showed high levels. The expansion of impervious surface was the main cause of the relatively large temporal increase in ecological risks from 2005 to 2015. Moreover, the strategies for ecological risk control can be divided into four categories based on the division of ISC, with 30%, 70%, and 90% as the thresholds. For risk control strategies, reducing ISC is the most important measure to reduce ecological risks for the category with an ISC range of 90%-100%, and increasing the area proportions of forests and water bodies is the most effective measure for the category with an ISC range of 0%-30%. For the other two categories, controlling the ISC and other strategies are required. Our study can increase the understanding of the influences of impervious surfaces on ecological risks in rapidly urbanizing regions and help inform the formulation of strategies for controlling the ecological risks in Beijing.

Sprayable methacrylic anhydride-modified gelatin hydrogel combined with bionic neutrophils nanoparticles for scar-free wound healing of diabetes mellitus.

Hard-to-healing or nonhealing diabetic wounds caused by hyperglycemia, bacterial infection and chronic inflammation are becoming a challenge globally. In this study, a novel hydrogel for diabetic wound healing composed of methacrylic anhydride-modified gelatin (GelMA) hydrogel and mimicking neutrophil nanoparticles was originally created. The prepared GelMA hydrogel has good sprayability and film-formation ability under blue light illumination (wavelength = 435-480 nm). Nanoparticles mimicking neutrophils belong to a double enzyme system that are encapsulated in ZIF-8 nanoparticles, which can consume glucose to produce HClO, ensuring a decrease in the glucose concentration of the wound and growth inhibition in bacteria. The hydrogel also has excellent biocompatibility, which can promote the growth and proliferation of fibroblasts. More importantly, the hydrogel can accelerate wound healing in type I diabetic rats owing to the downregulation of proinflammatory cytokines, and the wound with an area of 1 cm2 can be almost fully healed with no formation of the scar on the 21st day, as verified by histochemistry and immunohistochemistry. All these combinations indicate its potential in diabetic wound treatment.

KIF2A participates in the progression of hepatocellular carcinoma and angiogenesis by interacting with Notch1.

Kinesin family member 2A (KIF2A) serves a vital role in the development of hepatocellular carcinoma (HCC); however, the biological effect of KIF2A on the malignant progression of HCC remains unclear. Therefore, the present study was conducted to systematically determine the biological role of KIF2A in HCC and to better understand the molecular mechanism. The differences of KIF2A expression in HHL-5 normal human hepatocytes and the HCC cell lines Li-7, Huh7 and MHCC97 were assessed by reverse transcription-quantitative PCR and western blotting analysis. Moreover, viability, proliferation, migration and invasion of HCC cells were assessed by performing CCK-8, 5-ethynyl-2'-deoxyuridine staining, wound healing and Transwell assays. Additionally, the tube formation assay was performed to evaluate angiogenesis of HUVECs incubated with the conditioned media of HCC cells in vitro. The interaction between KIF2A and Notch1 was analyzed through co-immunoprecipitation assay. KIF2A was revealed to be highly expressed in HCC cells. KIF2A knockdown suppressed HCC cell proliferation, migration and invasion, and impaired in vitro angiogenesis. Furthermore, it was revealed that KIF2A interacted with Notch1 and positively regulated Notch1 expression. The suppressive effects of KIF2A knockdown on HCC cell proliferation, migration, invasion and in vitro angiogenesis were partially reversed by Notch1 overexpression. Overall, KIF2A may act as an oncogene in HCC via activation of the Notch1 signaling pathway.

Selenium-containing polysaccharides isolated from Rosa laevigata Michx fruits exhibit excellent anti-oxidant and neuroprotective activity in vitro.

Selenium-containing polysaccharides have potential as an organic selenium dietary supplement, owing to their low toxicity, few side effects, and easy absorption attributes. In this study, we isolated two novel homogeneous selenium-containing polysaccharides from Rosa laevigata Michx fruits (Se-RLFPs). Results from primary structural analysis revealed that Se-RLFPs were α - pyranose, and were both composed of rhamnose, xylose, glucose with an average molecular weight of 24 and 16 KDa, respectively. Selenium contents in Se-RLFP-I and Se-RLFP-II were 16.49 µg/g and 21.61 µg/g, respectively. Results from analysis of antioxidant and neuroprotective activity of the polysaccharides revealed that Se-RLFPs had a radical scavenging effect. Specifically, they effectively protected SH-SY5Y cells from H2O2-induced damage by enhancing antioxidant enzyme activities (SOD), total antioxidant capacity (T-AOC) and suppressing malondialdehyde (MDA) levels. Western blots showed that the underlying mechanisms of action may be related to the Nrf2/HO-1 signaling pathway. Taken together, these results suggested that Se-RLFPs have potential as a pharmaceutical agent for treatment of neurodegenerative diseases (NDDs) or as a selenium-complementary ingredient in functional foods.

A minimally manipulated preservation and virus inactivation method for amnion/chorion.

Allogeneic amnion tissues have been widely used in tissue repair and regeneration, especially a remarkable trend of clinical uses in chronic wound repair. The virus inactivation procedures are necessary and required to be verified for the clinical use and approval of biological products. Cobalt-60 (Co-60) or electron-beam (e-beam) is the common procedure for virus and bacterial reduction, but the excessive dose of irradiation was reported to be harmful to biological products. Herein, we present a riboflavin (RB)-ultraviolet light (UV) method for virus inactivation of amnion and chorion tissues. We used the standard in vitro limiting dilution assay to test the viral reduction capacity of the RB-UV method on amnion or chorion tissues loaded with four types of model viruses. We found RB-UV was a very effective procedure for inactivating viruses of amnion and chorion tissues, which could be used as a complementary method to Co-60 irradiation. In addition, we also screened the washing solutions and drying methods for the retention of growth factors.

Prognostic prediction of novel risk scores (AML-DRG and AML-HCT-CR) in acute myeloid leukemia patients with allogeneic hematopoietic stem cell transplantation.

We aimed to validate and prove the novel risk score models of acute myeloid leukemia (AML)-specific disease risk group (AML-DRG) and AML-Hematopoietic Cell Transplant-composite risk (AML-HCT-CR) in patients with acute myeloid leukemia (AML) after allogeneic hematopoietic stem cell transplantation (AHCT). Among the 172 AML patients analysed, 48.3% (n = 83) were females. Median age was 31.5 years (range 14 to 62 years), two patients was more than 60 years old (1.2%). Median follow-up was 44 months (range 1 to 94 months). According to the AML-DRG model, 109, 49 and 14 patients were in low-, intermediate- and high-risk group, respectively. According to the AML-HCT-CR model, 108, 30, 20 and 14 patients were in low-, intermediate-, high- and very high-risk group, respectively. Our results showed that the AML-DRG and AML-HCT-CR models significantly predicted cumulative incidence of relapse (p < 0.001; p < 0.001). But AML-DRG model was not associated with NRM (p = 0.072). Univariate analysis showed that the AML-DRG model could better stratify AML patients into different risk groups compared to the AML-HCT-CR model. Multivariate analysis confirmed that prognostic impact of AML-DRG and AML-HCT-CR models on post-transplant OS was independent to age, sex, conditioning type, transplant modality, and stem cell source (p < 0.001; p < 0.001). AML-DRG and AML-HCT-CR models can be used to effectively predict post-transplant survival in patients with AML receiving AHCT. Compared to AML-HCT-CR score, the AML-DRG score allows better stratification and improved survival prediction of AML patients post-transplant.

[Researches on pyretic pulmonary syndrome model interfered by Scutellariae Radix based on variation of biomarker].

OBJECTIVE: Metabonomics researches of Scutellariae Radix interfering pyretic pulmonary syndrome had been done, to determine the specific biomarkers of pyretic pulmonary syndrome, and to approach the mechanism that Scutellariae Radix interfered the variation of these biomarkers. METHOD: Metabonomics technique, UPLC-Q-TOF/MS analytical means and PCA statistical methods were utilized to investigate the trajectory change and inter-relationship of urinary metabolome of rats treated differently. RESULT: Six specific biomarkers were determined which could represent Streptococcus pneumoniae-induced pyretic pulmonary syndrome in rats. Scutellariae Radix could significantly adjust the ascended biomarkers to the normal level. Meanwhile two of these biomarkers were identified as Delta-12-prostaglandin J2 and indoxyl sulfate. CONCLUSION: There was a good therapeutic function of Scutellariae Radix on pyretic pulmonary syndrome, which was elucidated on the metabolic aspects. There was also a correlationship between the mechanism of Scutellariae Radix curing pyretic pulmonary syndrome and the six specific biomarkers.

[Effects of Chinese herbal medicine Huanglian Jiedu Decoction on urine metabonomics of healthy people].

OBJECTIVE: To study biomarkers and their diversification in healthy people's urine before and after oral administration of Huanglian Jiedu Decoction, a compound Chinese herbal medicine, and to investigate the influence of Huanglian Jiedu Decoction on urine metabonomics of healthy people. METHODS: Ten healthy volunteers joined in this experiment and signed informed consent. They were given oral administration of Huanglian Jiedu Decoction for 3 days, and their urine was collected every morning. The samples were centrifuged at 13 000×g for 10 min at 4 degrees centigrade, and the supernatant was stored at -75 degrees centigrade. The samples were examined by a core technology called ultra-performance liquid chromatography quadruple time of flight/mass spectrometry and then the data were analyzed by principal components analysis and partial least square-discriminant analysis to investigate trajectory diversification and corresponding relations of the time and amount of urine metabonomics before and after oral administration of Huanglian Jiedu Decoction. RESULTS: Evident variance of urine metabonomics took place after oral administration of Huanglian Jiedu Decoction, which showed that the metabolism of healthy people had been visibly affected. Seven potential biomarkers which play a role in healthy people on behalf of Huanglian Jiedu Decoction were preliminarily found, and one biomarker which had biological significance was identified as 2-(formylamino)-benzoic acid. CONCLUSION: The effects of Huanglian Jiedu Decoction on urine metabonomics in healthy people investigated at the level of metabolism can provide theoretical and technical support for the study of Huanglian Jiedu Decoction's influence on heat syndrome.

Coupling relation between urbanization and ecological risk of PAHs on coastal terrestrial ecosystem around the Bohai and Yellow Sea.

Urbanization, the ecological risks of polycyclic aromatic hydrocarbons (PAHs) to terrestrial ecosystems, and the complex relationship between them have drawn globally attention. In this paper, a comprehensive indicator system was calculated to illustrate the levels of urbanization in 20 coastal cities around the Bohai and Yellow Sea. The top three cities with high levels of urbanization were Tianjin > Qingdao > Dalian. The ecological risk of phenanthrene (Phe) was 52.0%; while the risk of fluoranthene (Flt) was 25.8%, and that of pyrene (Pyr), benzo[a]anthracene (Bap), fluorene (Flu), and naphthalene (Nap) were below 20% throughout the entire region. Risks were high in Dandong, Tianjin, Tangshan, Nantong, and Lianyungang and low in Weihai, Dongying, and Rizhao. The degree of coupling between urbanization and ecological risk of PAHs was above high (0.6) and more than 50% of the coordination degrees were slight unbalance [0.3, 0.5). Furthermore, redundancy analysis showed that the indicator aspects of industry, transportation, and population made great contribution to PAHs risk. Industry correlated to Low Molecular Weight (LMW) PAHs, while transportation correlated to High Molecular Weight (HMW) PAHs. To minimize risk, urbanization scale should be under acceptable level, or the structure of industry and transportation should be optimized.

The application of urban anthropogenic background to pollution evaluation and source identification of soil contaminants in Macau, China.

The anthropogenic background characterized by the accumulation characteristics of contaminants is recognized as an important evidence in pollution assessment and source identification in urban soil due to its less arbitrariness compared with the existing quality standards and the guidelines. A credible approach for pollution index calculation referring to anthropogenic background values (ABVs) combined with entropy weight method was developed. By the approach, the soil pollution degrees in Macau, China (one of the most densely populated region worldwide) were assessed based on the database of the heavy metals, Cd, Cu, Hg, Pb, and Zn, and high molecular weight polycyclic aromatic hydrocarbons (HMW PAHs) from 31 sites spatially distributed all over Macau. It was revealed that approximately half of the sites had no specific point source pollution. Mercury, benzo(a)anthracene (BaA), fluoranthene (FLT), and benzo(b)fluorantene (BbF), which had the highest weights were considered as the main contaminants. Macau Peninsula was identified as the critical polluted area. Then, the positive matrix factorization (PMF) coupled with ABVs as one of the data uncertainty inputs was used to identify the anthropogenic pollution sources of the contaminants. Three main anthropogenic sources with their contributions, including vehicle emissions (51.3%), use of hazard material (24.8%), and municipal or domestic waste (23.9%), could be well identified and quantified in the study area. The error estimation of the results showed that the variation of the contaminants in the derived factors were stable. The approaches which were in conformity with ABVs of soil contaminants are proved applicable in soil pollution assessment and source identification.

Amidase as a versatile tool in amide-bond cleavage: From molecular features to biotechnological applications.

Amidases (EC 3. 5. 1. X) are versatile biocatalysts for synthesis of chiral carboxylic acids, α-amino acids and amides due to their hydrolytic and acyl transfer activity towards the C-N linkages. They have been extensively exploited and studied during the past years for their high specific activity and excellent enantioselectivity involved in various biotechnological applications in pharmaceutical and agrochemical industries. Additionally, they have attracted considerable attentions in biodegradation and bioremediation owing to environmental pressures. Motivated by industrial demands, crystallographic investigations and catalytic mechanisms of amidases based on structural biology have witnessed a dramatic promotion in the last two decades. The protein structures showed that different types of amidases have their typical stuctural elements, such as the conserved AS domains in signature amidases and the typical architecture of metal-associated active sites in acetamidase/formamidase family amidases. This review provides an overview of recent research advances in various amidases, with a focus on their structural basis of phylogenetics, substrate specificities and catalytic mechanisms as well as their biotechnological applications. As more crystal structures of amidases are determined, the structure/function relationships of these enzymes will also be further elucidated, which will facilitate molecular engineering and design of amidases to meet industrial requirements.