Mechanistic insights into dissolved organic matter-driven protistan and bacterial community dynamics influenced by vegetation restoration.

Vegetation restoration projects can not only improve water quality by absorbing and transferring pollutants and nutrients from non-vegetation sources, but also protect biodiversity by providing habitat for biological growth. However, the mechanism of the protistan and bacterial assembly processes in the vegetation restoration project were rarely explored. To address this, based on 18 S rRNA and 16 S rRNA high-throughput sequencing, we investigated the mechanism of protistan and bacterial community assembly processes, environmental conditions, and microbial interactions in the rivers with (out) vegetation restoration. The results indicated that the deterministic process dominated the protistan and bacterial community assembly (94.29% and 92.38%), influenced by biotic and abiotic factors. For biotic factors, microbial network connectivity was higher in the vegetation zone (average degree = 20.34) than in the bare zone (average degree = 11.00). For abiotic factors, the concentration of dissolved organic carbon ([DOC]) was the most important environmental factor affecting the microbial community composition. [DOC] was lower significantly in vegetation zone (18.65 ± 6.34 mg/L) than in the bare zone (28.22 ± 4.82 mg/L). In overlying water, vegetation restoration upregulated the protein-like fluorescence components (C1 and C2) by 1.26 and 1.01-folds and downregulated the terrestrial humic-like fluorescence components (C3 and C4) by 0.54 and 0.55-folds, respectively. The different DOM components guided bacteria and protists to select different interactive relationships. The protein-like DOM components led to bacterial competition, whereas the humus-like DOM components resulted in protistan competition. Finally, the structural equation model was established to explain that DOM components can affect protistan and bacterial diversity by providing substrates, facilitating microbial interactions, and promoting nutrient input. In general, our study provides insights into the responses of vegetation restored ecosystems to the dynamics and interactives in the anthropogenically influenced river and evaluates the ecological restoration performance of vegetation restoration from a molecular biology perspective.

Herbal compound 861 prevents hepatic fibrosis by inhibiting the TGF-ß1/Smad/SnoN pathway in bile duct-ligated rats.

BACKGROUND: This study was to evaluate the effects of herbal compound 861 (Cpd861) on ski-related novel protein N (SnoN) and transforming growth factor-ß1 (TGF-ß1) /Smad signaling in rats with bile duct ligation (BDL)-induced hepatic fibrosis, and to explore the mechanisms of Cpd861 on hepatic fibrosis. METHODS: Thirty Wistar male rats were randomly divided into three groups: sham operation, BDL, and Cpd861. To induce hepatic fibrosis, BDL and Cpd861 group rats underwent bile duct ligation. Cpd861 at 9 g/kg/d or an equal volume of normal saline was administered intragastrically for 28 days. Liver injury was assessed biochemically and histologically. Protein and mRNA changes for SnoN and TGF-ß1/Smad signaling (TGF-ß1, Smad2, phosphorylated Smad2 [p-Smad2], phosphorylated Smad3 [p-Smad3], fibronectin, and collagen III) were determined by Western blotting and quantitative real-time PCR. RESULTS: BDL rats treated with Cpd861 had significantly alleviated hepatic fibrosis compared to BDL rats not receiving Cpd861 treatment. Moreover, Cpd861 decreased the expression of fibrosis-associated proteins fibronectin and collagen III in liver tissue. Cpd861 administration increased the expression of SnoN protein, did not change SnoN mRNA level, and decreased TGF-ß1, p-Smad2, and p-Smad3 protein expression compared to BDL without Cpd861 treatment. CONCLUSIONS: Cpd861 attenuates hepatic fibrosis by increasing SnoN protein expression and inhibiting the TGF-ß1/Smad signaling pathway.

Single-cell RNA transcriptomics reveals Du-Zhong-Wan promotes osteoporotic fracture healing via YAP/ß-catenin/VEGF axis in BMSCs.

BACKGROUND: Our previous study demonstrated that Du-Zhong-Wan (DZW) promoted osteoporotic fracture (OPF) healing by enhancing osteogenic differentiation of bone marrow mesenchymal stem cells (BMSCs) and angiogenesis of endothelial cells (ECs). However, the heterogeneity of BMSCs and ECs, as well as the specific molecular mechanism underlying these effects, still require further evaluation. PURPOSE: The primary objective of this study was to elucidate the heterogeneity of BMSCs and ECs, as well as the cellular-level mechanism of DZW against OPF through single-cell RNA sequencing. METHODS: In this study, we presented a single-cell atlas of mouse femoral callus, comparing samples with and without DZW treatment, utilizing single-cell RNA sequencing. Variable genes were identified using the FindVariableGenes (FVG) and principal component analysis (PCA) analysis. Additionally, uniform manifold approximation and projection (U-MAP) was employed to reduce and visualize the distinct subclusters. The CellPhoneDB2 method was employed to analyze intercellular communication and quantify the interaction between ligands and receptors within distinct cell clusters. The osteogenic differentiation capacity of BMSCs was assessed by micro-CT, alkaline phosphatase (ALP), and alizarin red S (ARS) assay. The scratch wound assay and tube formation assay were utilized to assess the angiogenic capabilities of ECs in vitro. Additionally, western blot and immunofluorescence experiments were utilized to elucidate the related protein expression. RESULTS: Consistent with our previous studies, DZW obviously promoted osteoporotic fracture healing. Moreover, this study discovered 14 cell clusters at the femoral fracture callus, where the BMSCs most actively interacted with ECs, through single-cell sequencing. Notably, DZW significantly elevated the proportion of Lepr+ BMSCs and Podxl+ ECs subgroup, which were respectively considered essential cells for osteoblastogenesis and angiogenesis of arteriolar vessels. The increased proportion of Podxl+ ECs was partially attributed to vascular endothelial growth factor (VEGF), secreted by BMSCs, which were able to be reversed by YAP pharmacological inhibitor verteporfin. Furthermore, the western blot assay revealed elevated expression levels of YAP/ß-catenin, VEGF, RUNX2, and OCN in BMSCs treated with DZW, which were counteracted by verteporfin. CONCLUSION: The data above indicates that DZW elevates the proportion of LEPR+ BMSCs and Podxl+ ECs, therefore contributing for the osteogenic ability of BMSCs and BMSCs-mediated angiogenesis via activation of the YAP/ß-catenin/VEGF axis, which provides novel potential targets and mechanism for DZW in treating OPF in sub-clusters and molecular level.

Baicalein improves the symptoms of polycystic ovary syndrome by mitigating oxidative stress and ferroptosis in the ovary and gravid placenta.

BACKGROUND: Polycystic ovary syndrome is a metabolic and hormonal disorder that is closely linked to oxidative stress. Within individuals diagnosed with PCOS, changes occur in the ovaries, resulting in an excessive buildup of iron and peroxidation of lipids, both of which may be associated with the occurrence of ferroptosis. Baicalein, a flavonoid found in the roots of Scutellaria baicalensis and widely known as Chinese skullcap, is known for its anti-inflammatory and anti-ferroptotic properties, which protect against various diseases. Nevertheless, there has been no investigation into the impact of baicalein on polycystic ovary syndrome. PURPOSE: This study aimed to correlate ferroptosis with polycystic ovary syndrome and to assess the effects of baicalein on ovarian dysfunction and placental development in pregnant patients. STUDY DESIGN AND METHODS: Polycystic ovary syndrome was induced in a rat model through the administration of dehydroepiandrosterone, and these rats were treated with baicalein. Oxidative stress and inflammation levels were assessed in serum and ovaries, and tissue samples were collected for histological and protein analyses. Furthermore, different groups of female rats were mated with male rats to observe pregnancy outcomes and tissue samples were obtained for histological, protein, and RNA sequencing. Then, RNA sequencing of the placenta was performed to determine the key genes involved in ferroptosis negative regulation (FNR) signatures. RESULTS: Baicalein was shown to reduce ovarian oxidative stress and pathology. Baicalein also ameliorated polycystic ovary syndrome by decreasing lipid peroxidation and chronic inflammation and modulating mitochondrial functions and ferroptosis in the ovaries. Specifically, glutathione peroxidase and ferritin heavy chain 1 were considerably downregulated in polycystic ovary syndrome gravid rats compared to their expression in the control group, and most of these differences were reversed after baicalein intervention. CONCLUSIONS: Our findings, initially, indicated that baicalein could potentially enhance the prognosis of individuals suffering from polycystic ovary syndrome by reducing oxidative stress and ferroptosis, thus potentially influencing the formulation of a therapeutic approach to address this condition.

L-Cysteine: A promising nutritional supplement for alleviating anxiety disorders.

Anxiety disorders are prevalent chronic psychological disease with complex pathogenic mechanisms. Current anxiolytics have limited efficacy and numerous side effects in many anxiety patients, highlighting the urgent need for new therapies. Recent research has been focusing on nutritional supplements, particularly amino acids, as potential therapies for anxiety disorders. Among these, L-Cysteine plays a crucial role in various biological processes. L-Cysteine exhibits antioxidant properties that can enhance the antioxidant functions of the central nervous system (CNS). Furthermore, metabolites of L-cysteine, such as glutathione and hydrogen sulfide have been shown to alleviate anxiety through distinct molecular mechanisms. Long-term administration of L-Cysteine has anxiolytic, antidepressant, and memory-improving effects. L-Cysteine depletion can lead to increased oxidative stress in the brain. This review delves into the potential mechanisms of L-Cysteine and its main products, glutathione (GSH) and hydrogen sulfide (H2S) in the management of anxiety and related diseases.

Multi-message multi-receiver signcryption scheme based on blockchain.

In conventional message communication systems, the practice of multi-message multi-receiver signcryption communication encounters several challenges, including the vulnerability to Key Generation Center (KGC) attacks, privacy breaches and excessive communication data volume. The KGC necessitates a secure channel to transmit partial private keys, thereby rendering the security of these partial private keys reliant on the integrity of the interaction channel. This dependence introduces concerns regarding the confidentiality of the private keys. Our proposal advocates for the substitution of the KGC in traditional certificateless schemes with blockchain and smart contract technology. Parameters are publicly disclosed on the blockchain, leveraging its tamper-proof property to ensure security. Furthermore, this scheme introduces conventional encryption techniques to achieve user identity privacy in the absence of a secure channel, effectively resolving the issue of user identity disclosure inherent in blockchain-based schemes and enhancing communication privacy. Moreover, users utilize smart contract algorithms to generate a portion of the encrypted private key, thereby minimizing the possibility of third-party attacks. In this paper, the scheme exhibits resilience against various attacks, including KGC leakage attacks, internal privilege attacks, replay attacks, distributed denial of service attacks and Man-in-the-Middle (MITM) attacks. Additionally, it possesses desirable security attributes such as key escrow security and non-repudiation. The proposed scheme has been theoretically and experimentally analyzed under the random oracle model, based on the computational Diffie-Hellman problem and the discrete logarithm problem. It has been proven to possess confidentiality and unforgeability. Compared with similar schemes, our scheme has lower computational cost and shorter ciphertext length. It has obvious advantages in communication and time overhead.

Telmisartan attenuates hepatic fibrosis in bile duct-ligated rats.

AIM: To evaluate the antifibrotic effect of telmisartan, an angiotensin II receptor blocker, in bile duct-ligated rats. METHODS: Adult Sprague-Dawley rats were allocated to 3 groups: sham-operated rats, model rats underwent common bile duct ligation (BDL), and BDL rats treated with telmisartan (8 mg/kg, po, for 4 weeks). The animals were sacrificed on d 29, and liver histology was examined, the Knodell and Ishak scores were assigned, and the expression of angiotensin-converting enzyme (ACE) and ACE2 was evaluated with immunohistochemical staining. The mRNAs and proteins associated with liver fibrosis were evaluated using RTQ-PCR and Western blot, respectively. RESULTS: The mean fibrosis score of BDL rats treated with telmisartan was significantly lower than that of the model rats (1.66±0.87 vs 2.13±0.35, P=0.015). However, there was no significant difference in inflammation between the two groups, both of which showed moderate inflammation. Histologically, treatment with telmisartan significantly ameliorated BDL-caused the hepatic fibrosis. Treatment with telmisartan significantly upregulated the mRNA levels of ACE2 and MAS, and decreased the mRNA levels of ACE, angiotensin II type 1 receptor (AT1-R), collagen type III, and transforming growth factor ß1 (TGF-ß1). Moreover, treatment with telmisartan significantly increased the expression levels of ACE2 and MAS proteins, and inhibited the expression levels of ACE and AT1-R protein. CONCLUSION: Telmisartan attenuates liver fibrosis in bile duct-ligated rats via increasing ACE2 expression level.

Immune regulation in polycystic ovary syndrome.

A polycystic ovarian syndrome (PCOS) is the most common endocrine disorder affecting females. Furthermore, it is a heterogeneous disease with a variety of etiologies and outcomes. Patients frequently complain about infertility, irregular menstruation, acne, seborrheic dermatitis, hirsutism, and obesity. PCOS can be caused by hypothalamic-pituitary-ovarian axis dysfunction, heredity, or metabolic abnormalities. PCOS is characterized by chronic low-level inflammation, which includes an imbalance in pro-inflammatory factor secretion, endothelial cell dysfunction, and leukocytosis. PCOS is also distinguished by hormonal and immune dysregulation. During PCOS, immune cells and immune regulatory molecules play critical roles in maintaining metabolic homeostasis and regulating immune responses. Because of oligo/anovulation, patients with PCOS have low progesterone levels. Therefore, low progesterone levels in PCOS overstimulate the immune system, causing it to produce more estrogen, which leads to a variety of autoantibodies. This review aims to summarize the immune regulation involved in the pathogenesis of PCOS and pave the way for the development of better PCOS treatment options in the near future.

[Down-regulation of PTEN expression in kidney and its role in development of diabetic nephropathy in rats].

Transforming growth factor-ß1 (TGF-ß1)-activated phosphoinositide-3-kinase (PI3K)-protein kinase B (PKB/Akt) pathway is intimately related to the development of diabetic nephropathy (DN), which is negatively regulated by phosphatase and tensin homolog deleted on chromosome ten (PTEN). The present study was to investigate the expression of PTEN in the renal tissue of diabetic mellitus (DM) rats and explore its possible effect on development of DN. Sixteen Sprague-Dawley rats were divided into normal control group (n = 8) and diabetic group (n = 8) at random. Streptozotocin injection was used to establish diabetic model. After 12 weeks, the rats were sacrificed to detect relative biochemical parameters and renal index, and to observe the changes of pathomorphology by HE staining as well. In addition, immunohistochemistry staining and Western blotting were employed to detect the protein expression of PTEN, TGF-ß1, PI3Kp110α, Akt1, p-Akt1 (Ser(473)), fibronectin (FN) and Collagen IV, respectively. Furthermore, the expression of PTEN mRNA was also examined by RT-PCR. The results indicated that the levels of blood glucose, serum creatinine and urine protein (24 h) were increased remarkably in the diabetic group (P < 0.05) compared with those in the control group. Compared with those in the control group, the protein expressions of TGF-ß1, PI3Kp110α, Akt1 in renal tubular epithelium and the expressions of FN and CollagenIV in renal interstitium were increased in the diabetic group (P < 0.05). The expression of PTEN in the diabetic group was significantly reduced than that in the control group (P < 0.05), and the expression of p-Akt1 (Ser(473)) increased remarkably in the diabetic group which had the similar trend to Akt1 (P < 0.05). PTEN mainly located in renal tubular epithelial cells. The expression of PTEN had negative correlation to that of p-Akt1 (Ser(473)). Compared with that in the control group, the expression of PTEN mRNA was decreased remarkably in the diabetic group (P < 0.05). The data suggest that the down-regulation of PTEN in renal tissue of DM rats may promote the PI3K-PKB/Akt pathway over-activated by TGF-ß1, which facilitates the initiation and development of DN.

Congenital bilateral cryptorchidism in an infant conceived after maternal breast cancer treatment: A case report.

BACKGROUND: The incidence of breast cancer among women of reproductive age is increasing, as well as the desire for children at late childbearing age. Identifying factors that may be associated with fetal malformation and maternal and fetal prognosis has gained importance. We describe a 32-year-old woman with breast cancer who gave birth to a son with congenital bilateral cryptorchidism after treatment, with a literature review performed. CASE SUMMARY: A 32-year-old woman with breast cancer who had been treated by surgery and radiotherapy experienced recurrence and underwent a second surgery, adjuvant chemotherapy, and targeted therapy. Her tumor cells were negative for estrogen receptor (ER) α, progesterone receptor (PR), and p53; positive for ERß, human epidermal growth factor receptor-2 (HER2), epidermal growth factor receptor (EGFR), and Ki67. She had pathogenic BRCA gene mutations. She became pregnant within 2 years and delivered a boy with congenital bilateral cryptorchidism. The boy underwent bilateral orchidopexy. As of this writing, the woman and her son are both healthy. CONCLUSION: HER2 overexpression, positivity for EGFR, Ki67, and ER, and PR negativity are associated with a poor prognosis in breast cancer. While no link has been established statistically between treatment for breast cancer and cryptorchidism in a subsequent pregnancy, this case suggests the possibility that ERß and gene mutations may be contributing factors.

Research progress in bioremediation of petroleum pollution.

With the enhancement of environmental protection awareness, research on the bioremediation of petroleum hydrocarbon environmental pollution has intensified. Bioremediation has received more attention due to its high efficiency, environmentally friendly by-products, and low cost compared with the commonly used physical and chemical restoration methods. In recent years, bacterium engineered by systems biology strategies have achieved biodegrading of many types of petroleum pollutants. Those successful cases show that systems biology has great potential in strengthening petroleum pollutant degradation bacterium and accelerating bioremediation. Systems biology represented by metabolic engineering, enzyme engineering, omics technology, etc., developed rapidly in the twentieth century. Optimizing the metabolic network of petroleum hydrocarbon degrading bacterium could achieve more concise and precise bioremediation by metabolic engineering strategies; biocatalysts with more stable and excellent catalytic activity could accelerate the process of biodegradation by enzyme engineering; omics technology not only could provide more optional components for constructions of engineered bacterium, but also could obtain the structure and composition of the microbial community in polluted environments. Comprehensive microbial community information lays a certain theoretical foundation for the construction of artificial mixed microbial communities for bioremediation of petroleum pollution. This article reviews the application of systems biology in the enforce of petroleum hydrocarbon degradation bacteria and the construction of a hybrid-microbial degradation system. Then the challenges encountered in the process and the application prospects of bioremediation are discussed. Finally, we provide certain guidance for the bioremediation of petroleum hydrocarbon-polluted environment.

Dual specific CD19/CD22-targeted chimeric antigen receptor T-cell therapy for refractory diffuse large B-cell lymphoma: A case report.

Clinical trials of chimeric antigen receptors (CARs) targeting CD19 have produced impressive results in hematological malignancies, including diffuse large B-cell lymphoma (DLBCL). However, a notable number of patients with DLBCL fail to achieve remission after CD19 CAR T-cell therapy and may therefore require a dual targeted CAR T-cell therapy. A 31-year-old man with refractory DLBCL was assessed in the present case report. The patient was treated with sequential infusion of single CD19 CAR T cells followed by dual CD19/CD22-targeted CAR T cells. The outcome was that the patient achieved partial remission after the first single CD19 CAR T-cell infusion and complete remission after the dual CD19/CD22-targeted CAR T-cell infusion. Grade 1 cytokine release syndrome (CRS) was observed after the single CD19 CAR T-cell infusion, while grade 3 CRS and hemophagocytic syndrome were observed after the dual targeted CAR T-cell infusion, but these adverse effects alleviated after the treatments. To the best of our knowledge, the present case report is the first to describe the successful application of dual CD19/CD22-targeted CAR T-cell therapy for the treatment of refractory DLBCL. The report suggests that dual CD19/CD22-targeted CAR T-cell therapy may represent a promising option for the treatment of refractory DLBCL; however, caution should be taken due to potential CRS development.

[Analysis of the Temporal and Spatial Distribution of the Diversity of the Denitrifying Anaerobic Methane-Oxidizing Bacterial Community in the Sediments of the Hunhe River and Its Relationship with Environmental Factors].

16S rRNA and pmoA functional genes were used as biomarker genes to investigate the temporal and spatial distribution of community diversity of Candidatus Methylomirabilis oxyfera (M. oxyfera) in the sediments of the Hunhe River by clone library technology. The dependence relationship between the physicochemical property of water and sediment samples and the diversity characteristics of the M. oxyfera community were analyzed by multivariate direct gradient analysis. Among the examples collected in September 2014, the OTU number of the 16S rRNA gene of M. oxyfera was 2-5, the Shannon-Wiener diversity index was 0.21-1.4, and the distribution characteristics in the middle reaches > upstream > downstream were presented. The OTU number and Shannon-Wiener diversity index of the pmoA functional gene in upstream samples are significantly higher than those in the middle and lower reach samples, and the Shannon-Wiener diversity indices in the upstream samples are 3.5 times and 2.3 times higher than that of the middle and the downstream samples, respectively. The community diversity of M. oxyfera showed a distinct regional distribution. Samples were collected at 3 sampling points in March 2015. The OTU values of 16S rRNA and pmoA for M. oxyfera are 6 and 5 respectively, which were obviously higher than those in September 2014. The Shannon-Wiener index is also higher than that in September 2014 (1.4>0.68; 57>0.00). The community diversity of M. oxyfera showed obvious seasonal distribution characteristics. Multivariate direct gradient analysis results showed that the concentration of DOC in water, sediment conductivity, TOC concentration, and nitrite concentration in the sediment are the main environmental factors affecting the community diversity of M. oxyfera.

Surface reaction of Bacillus cereus biomass and its biosorption for lead and copper ions.

In this study, the surface chemical functional groups of Bacillus cereus biomass were identified by Fourier transform infrared (FTIR) analytical technique. It had been shown that the B. cereus cells mainly contained carboxyl, hydroxyl, phosphate, amino and amide functional groups. The potentiometric titration was conducted to explain the surface acid-base properties of aqueous B. cereus biomass. The computer program FITEQL 4.0 was used to perform the model calculations. The optimization results indicated that three sites-three pKas model, which assumed the cell surface to have three distinct types of surface organic functional groups based on the IR analysis results, simulated the experimental results very well. Moreover, batch adsorption experiments were performed to investigate biosorption behavior of Cu(II) and Pb(II) ions onto the biomass. Obviously, the adsorption equilibrium data for the two ions were reasonably described by typical Langmuir isotherm.

Fibronectin expression is critical for liver fibrogenesis in vivo and in vitro.

Increased fibronectin (FN) expression has an important role during liver fibrosis. The present study examined FN expression in rats subjected to carbon tetrachloride (CCl4)­induced liver fibrosis. In addition, the potential mechanisms underlying fibrogenesis were investigated by exposing hepatic stellate cells (HSCs) to transforming growth factor­ß (TGF­ß), which is a known inducer of myofibroblastic transformation of HSCs. Briefly, a rat model of liver fibrosis was created by administering intraperitoneal injections of CCl4. Furthermore, HSC­T6 cells were stimulated with increasing doses of recombinant TGF­ß over 24 h. Hepatic fibrosis gradually increased following CCl4 administration in vivo. Western blotting and immunohistochemistry demonstrated that fibronectin (FN), TGF­ß and α­smooth muscle actin (SMA) expression was increased following CCl4 injection, and the maximum expression levels were observed at 8 weeks. Once CCl4 treatment had been terminated, the expression levels of FN, TGF­ß and α­SMA progressively declined to near baseline levels. Western blotting and quantitative polymerase chain reaction demonstrated that FN expression was gradually increased in response to TGF­ß­stimulation of HSCs; maximum expression was achieved 12 h post­treatment (P<0.01 vs. the baseline). In conclusion, these findings indicated that FN expression is an early and progressive event that occurs during liver fibrogenesis in vivo and in vitro.

Sequence-based screening and characterization of cytosolic mandelate oxidase using oxygen as electron acceptor.

Sequence-based screening was carried out to find a type of cytosolic mandelate oxidase that converted l-mandelate to phenylglyoxylate using oxygen as the final electron acceptor. The sequence features of the cytosolic mandelate oxidase were summarized, and were used in the screening process. Mandelate oxidases from Streptomyces coelicolor (HmoSC) and Amycolatopsis orientalis (HmoAO) were screened and then they were heterologously expressed and characterized. At pH 7.3 40 °C, the HmoAO showed kcat and Km values of 140 min(-1) and 10.2 mM, the HmoSC showed kcat and Km values of 105.1 min(-1) and 2.06 mM. The HmoSC was thermal stable and retained its 90% activity at 60 °C for up to 5 h, while HmoAO lost most of its activity at this temperature. The HmoSC could effectively catalyze the conversion of l-mandelate to phenylglyoxylate at higher temperature using oxygen as the final electron acceptor.

Kinetics study of aqueous sorption of phenanthrene to humic acids and sediments.

The sorption behavior was determined for a model polycyclic aromatic hydrocarbon (PAH), i.e., phenanthrene(PHN), from water to three humic acids (HAs) and three sediments in different reacting time. The chemical compositions of HA samples were measured using cross polarization magic angle spinning carbon-13 (CPMAS 13C NMR along with elemental analysis. The dissolved humic substances dissociating from solid HAs and sediments were characterized by 'H NMR. The experiments indicated that the sorption modes and mechanisms of natural sorbents for PHN varied significantly between short (< 7 d) and long contact time and the reaction time should be taken into consideration in studying the overall sorption process. The sorption capacity (K'f) and exponent (n) might be relative to the properties of dissolved humic materials in initial stage but the solid aromatic organic matter after long time reaction. According to the experiments performed in this investigation and the previous researches, a conceptive sorption model was established.

[Fluorescence characteristics of fractionated colloidal organic matter in freshwater from Hunhe and Taizihe watersheds].

The ultrafiltration system with molecular mass of 100 x 10(3) and 1 x 10(3) membrane was used for the fractionation of total dissolved organic matter (DOM) in waters from Hunhe and Taizihe Watersheds. The fluorescence properties of colloidal organic matter with different sizes were investigated using a three-dimension excitation-emission matrix (3-D EEM) fluorescence spectroscopy. It was shown that the tryptophan-, fuvic-and humic-like materials were presented in the waters from Hunhe and Taizihe Watersheds, of which fuvic-and humic-like materials were mainly in colloidal form with small size (relative molecular mass < 100 x 10(3)) and truly dissolved phase (relative molecular mass < 1 x 10(3)). The adsorption of protein-like matters onto the colloid particles made the majority of these materials in colloidal phase though they had a low molecular mass. The higher percentages of small colloidal and truly dissolved organic carbon in total dissolved organic carbon (DOC) were observed in the water samples collected in wet season. Fluorescence index (FI), index of recent autochthonous contribution (BIX) and humification index (HIX) indicated that humic-like components in truly dissolved phase were mainly originated from autochthonous source and colloidal humic-like components were mainly derived from terrestrial organic matter. The recent autochthonous organic matter made a major contribution to truly dissolved phase. The humic-like matter was the domain of DOC content, but the contribution of protein-like materials to the organic carbon was not negligible due to the pollution of waterbody by industrial wastewater discharge.

Heterologous pathway for the production of L-phenylglycine from glucose by E. coli.

The aproteinogenic amino acid L-phenylglycine (L-Phg) is an important side chain building block for the preparation of several antibiotics and taxol. To biosynthesis L-Phg from glucose, an engineered Escherichia coli containing L-Phg synthetic genes was firstly developed by an L-phenylalanine producing chassis supplying phenylpyruvate. The enzymes HmaS (L-4-hydroxymandelate synthase), Hmo (L-4-hydroxymandelate oxidase) and HpgT (L-4-hydroxyphenylglycine transaminase) from Amycolatopsis orientalis as well as Streptomyces coelicolor were heterologously expressed in E. coli and purified to evaluate their abilities on L-Phg formation. HpgT conversing phenylglyoxylate to L-Phg uses an unusual amino donor L-phenylalanine, which releases another phenylpyruvate as the substrate of HmaS. Thus, a recycle reaction was developed to maximize the utilization of precursor phenylpyruvate. To amplify the accumulation of L-Phg, the effects of attenuating L-phenylalanine transamination was investigated. After deletion of tyrB and aspC, L-Phg yield increased by 12.6-fold. The limiting step in the L-Phg biosynthesis was also studied; the L-Phg yield was further improved by 14.9-fold after enhancing hmaS expression. Finally, by optimizing expression of hmaS, hmo and hpgT and attenuation of L-phenylalanine transamination, the L-Phg yield was increased by 224-fold comparing with the original strain.