Complete genome sequencing and investigation on the fiber-degrading potential of Bacillus amyloliquefaciens strain TL106 from the tibetan pig.

BACKGROUND: Cellulolytic microorganisms are considered a key player in the degradation of feed fiber. These microorganisms can be isolated from various resources, such as animal gut, plant surfaces, soil and oceans. A new strain of Bacillus amyloliquefaciens, TL106, was isolated from faeces of a healthy Tibetan pigs. This strain can produce cellulase and shows strong antimicrobial activity in mice. Thus, in this study, to better understand the strain of B. amyloliquefaciens TL106 on degradation of cellulose, the genome of the strain TL106 was completely sequenced and analyzed. In addition, we also explored the cellulose degradation ability of strain TL106 in vitro. RESULTS: TL106 was completely sequenced with the third generation high-throughput DNA sequencing. In vitro analysis with enzymatic hydrolysis identified the activity of cellulose degradation. TL106 consisted of one circular chromosome with 3,980,960 bp and one plasmid with 16,916 bp, the genome total length was 3.99 Mb and total of 4,130 genes were predicted. Several genes of cellulases and hemicellulase were blasted in Genbank, including ß-glucosidase, endoglucanase, ß-glucanase and xylanase genes. Additionally, the activities of amylase (20.25 U/mL), cellulase (20.86 U/mL), xylanase (39.71 U/mL) and ß-glucanase (36.13 U/mL) in the fermentation supernatant of strain TL106 were higher. In the study of degradation characteristics, we found that strain TL106 had a better degradation effect on crude fiber, neutral detergent fiber, acid detergent fiber, starch, arabinoxylan and ß-glucan of wheat and highland barley . CONCLUSIONS: The genome of B. amyloliquefaciens TL106 contained several genes of cellulases and hemicellulases, can produce carbohydrate-active enzymes, amylase, cellulase, xylanase and ß-glucanase. The supernatant of fermented had activities of strain TL106. It could degrade the fiber fraction and non-starch polysaccharides (arabinoxylans and ß-glucan) of wheat and highland barley. The present study demonstrated that the degradation activity of TL106 to crude fiber which can potentially be applied as a feed additive to potentiate the digestion of plant feed by monogastric animals.

Autocatalytic Morphology Transformation Platform for Targeted Drug Accumulation.

The precise and highly efficient drug delivery of nanomedicines into lesions remains a critical challenge in clinical translational research. Here, an autocatalytic morphology transformation platform is presented for improving the tumor-specific accumulation of drugs by kinetic control. The in situ reorganization of prodrug from nanoparticle to ß-sheet fibrous structures for targeted accumulation is based on nucleation-based growth kinetics. During multiple administrations, the autocatalytic morphology transformation can be realized for skipping slow nucleating process and constructing the bulky nanoassembly instantaneously, which has been demonstrated to induce the cumulative effect of prodrug. Furthermore, the sustained drug release from fibrous prodrug depot in the tumor site inhibits the tumor growth efficiently. The autocatalytic morphology transformation strategy in vivo offers a novel perspective for targeted delivery strategy by introducing chemical kinetics and shows great potential in disease theranostics.

Endogenous Reactive Oxygen Species-Triggered Morphology Transformation for Enhanced Cooperative Interaction with Mitochondria.

The morphology controlled molecular assemblies play vital roles in biological systems. Here we present endogenous reactive oxygen species (ROS)-triggered morphology transformation of polymer-peptide conjugates (PPCs) for cooperative interaction with mitochondria, exhibiting high tumor therapeutic efficacy. The PPCs are composed of (i) a ß-sheet-forming peptide KLVFF conjugated with poly(ethylene glycol) through ROS-cleavable thioketal, (ii) a mitochondria-targeting cytotoxic peptide KLAK, and (iii) a poly(vinyl alcohol) backbone. The self-assembled PPCs nanoparticles can enter cells and target mitochondria. Because of overgenerated ROS around mitochondria in most cancer cells, the thioketal linker can be cleaved, leading to transformation from nanoparticles to fibrous nanostructures. As a result, the locational nanofibers with exposure of KLAK exhibit enhanced multivalent cooperative interactions with mitochondria, which causes selective cytotoxicity against cancer cells and powerful tumor suppression efficacy in vivo. As the first example of ROS-triggered intracellular transformation, the locational assembly strategy in vivo may provide a new insight for disease diagnosis and therapy through enhanced interaction with targeting site.

Microenvironment-Induced In Situ Self-Assembly of Polymer-Peptide Conjugates That Attack Solid Tumors Deeply.

In cancer treatment, the unsatisfactory solid-tumor penetration of nanomaterials limits their therapeutic efficacy. We employed an in vivo self-assembly strategy and designed polymer-peptide conjugates (PPCs) that underwent an acid-induced hydrophobicity increase with a narrow pH-response range (from 7.4 to 6.5). In situ self-assembly in the tumor microenvironment at appropriate molecular concentrations (around the IC50 values of PPCs) enabled drug delivery deeper into the tumor. A cytotoxic peptide KLAK, decorated with the pH-sensitive moiety cis-aconitic anhydride (CAA), and a cell-penetrating peptide TAT were conjugated onto poly(ß-thioester) backbones to produce PT-K-CAA, which can penetrate deeply into solid tumors owing to its small size as a single chain. During penetration in vivo, CAA responds to the weak acid, leading to the self-assembly of PPCs and the recovery of therapeutic activity. Therefore, a deep-penetration ability for enhanced cancer therapy is provided by this in vivo assembly strategy.

In Situ Monitoring Intracellular Structural Change of Nanovehicles through Photoacoustic Signals Based on Phenylboronate-Linked RGD-Dextran/Purpurin 18 Conjugates.

The stimuli-responsive polymeric nanocarriers have been studied extensively, and their structural changes in cells are important for the controlled intracellular drug release. The present work reported RGD-dextran/purpurin 18 conjugates with pH-responsive phenylboronate as spacer for monitoring the structural change of nanovehicles through ratiometric photoacoustic (PA) signal. Phenylboronic acid modified purpurin 18 (NPBA-P18) could attach onto the RGD-decorated dextran (RGD-Dex), and the resulting RGD-Dex/NPBA-P18 (RDNP) conjugates with different molar ratios of RGD-Dex and NPBA-P18 were prepared. When the moles of NPBA-P18 were equivalent to more than triple of RGD-Dex, the single-stranded RDNP conjugates could self-assemble into nanoparticles in aqueous solution due to the fairly strong hydrophobicity of NPBA-P18. The pH-responsive aggregations of NPBA-P18 were investigated by UV-vis, fluorescence, and circular dichroism spectra, as well as transmission electron microscope. Based on distinct PA signals between monomeric and aggregated state, ratiometric PA signal of I750/I710 could be presented to trace the structural change progress. Compared with RDNP single chains, the nanoparticles exhibited effective cellular internalization through endocytosis pathway. Furthermore, the nanoparticles could form well-ordered aggregates responding to intracellular acidic environment, and the resulting structural change was also monitored by ratiometric PA signal. Therefore, the noninvasive PA approach could provide a deep insight into monitoring the intracellular structural change process of stimuli-responsive nanocarriers.

Expression and Characterization of Laccase Lac1 from Coriolopsis trogii Strain Mafic-2001 in Pichia pastoris and Its Degradation of Lignin.

The laccase gene (Lac1) was cloned from Coriolopsis trogii strain Mafic-2001. Full-length sequence of Lac1 containing 11 exons and 10 introns is composed of 2140 nucleotides (nts). mRNA of Lac1 encoded for a protein of 517 aa. Nucleotide sequence of the laccase was optimized and expressed in Pichia pastoris X-33. SDS-PAGE analysis showed that the molecular weight of the purified recombinant laccase rLac1 was about 70 kDa. The optimum temperature and pH of rLac1 were 40 ℃ and 3.0, respectively. rLac1 showed high residual activity (90%) in the solutions after 1 h incubation at the pH ranging from 2.5 to 8.0. rLac1 maintained over 60% of laccase activity at the temperatures ranging from 20 to 60 °C, and kept higher than 50% of its activity at 40 °C for 2 h. The activity of rLac1 was promoted by Cu2+ and inhibited by Fe2+. Under optimal conditions, lignin degradation rates of rLac1 on the substrates of rice straw, corn stover, and palm kernel cake were 50.24%, 55.49%, and 24.43% (the lignin contents of substrates untreated with rLac1 were 100%), respectively. Treated with rLac1, the structures of agricultural residues (rice straw, corn stover, and palm kernel cake) were obviously loosened which was reflected by the analysis of scanning electron microscopy and Fourier transform infrared spectroscopy. Based on the specific activity of rLac1 on the degradation of lignin, rLac1 from Coriolopsis trogii strain Mafic-2001 has the potential for in-depth utilization of agricultural residues.

Intracellular Self-Immolative Polyprodrug with Near-Infrared Light Guided Accumulation and in Vivo Visualization of Drug Release.

The selective accumulation and real-time monitoring of drug release at tumor site are the key bottlenecks to the clinical translation of polyprodrug. Herein, an intracellular self-immolative polyprodrug (PMTO) is exploited, which not only shows the enhanced cellular internalization and selective accumulation in tumor site under the mild hyperthermia triggered by laser irradiation, but also possesses the self-monitoring drug release ability in vivo. The polyprodrug amphiphiles are synthesized by sequential esterification reaction, and hydrophilic poly(ethylene glycol) serves as blocking agent. On account of the mild hyperthermia produced by PMTO under the laser irradiation at tumor site, the cell membranous permeability increases, resulting in the enhanced cellular internalization and drug accumulation in tumor. After internalized by cells, the self-immolative PMTO nanoparticles can release free mitoxantrone (MTO) in intracellular reductive environment, and ratiometric photoacoustic imaging based on distinct signals between MTO and PMTO is presented to trace the drug release in vivo. Finally, this self-monitoring polyprodrug presents significant tumor suppression efficacy, which exhibits great potential for guiding the clinical medication in cancer treatment.

A new species of the Achalinus rufescens complex (Xenodermidae: Achalinus) from Fujian Province, China.

A new species of the xenodermid snake genus Achalinus Peters, 1869 is described from Fujian Province, China, based on six specimens. Bayesian inference and maximum likelihood analyses based on a mitochondrial DNA fragment (CO1) indicated the new taxon is different from its congeners (pdistance ≥ 18.5%). Morphologically, the new species can be diagnosed from the other species by a combination of following characters: (1) dorsal scales 23 rows throughout, strongly keeled, the most outer rows on both sides also keeled and slightly enlarged; (2) tail relatively longer, TaL/TL ratio 0.260.29 in males, 0.210.22 in females; (3) maxillary teeth 3033; (4) length of suture between internasals significantly longer than that between prefrontals; (5) nasal divided into two sections by nasal cleft; (6) a single loreal; (7) SPO 1, seldom 2; (8) SPL 6, the fourth and fifth contacting eye; (9) IFL5, rarely 6, the first three touching the first pair of chin shields; (10) TMP 79, arranged in three rows; (11) VS 142149 in males, VS 152154 in females; (12) SC 7481 in males, SC 6365 in females, arranged in a single row; (13) cloacal entire; (14) greyish brown above, pale yellow beneath; (15) dorsum with an indistinct longitudinal vertebral stripe. The description of the new species brings the total species of Achalinus to 19.

Extraction and quantitative analysis of tropane alkaloids in Radix physochlainae by emulsion liquid membrane with tropine-based ionic liquid.

Emulsion liquid membrane (ELM) coupled with tropine-based ionic liquid was prepared and successfully adopted for the extraction and quantitative analysis of tropane alkaloids (TA) in Radix physochlainae. Effects of formation conditions of ELM were explored and then optimized; the ideal oil-water mass ratio was determined to be 1:2.5, chloroform, Span 80 and 0.05 mol L-1N-propyl-tropine hexafluorophosphate ([C3Tr][PF6]) aqueous solution were stirred for 30 min with the speed of 1500 r min-1. In order to extract and enrich TA with ELM efficiently, key factors related with their extraction efficiency such as stirring speed, volume of the extracts (feed solution), migration time and initial concentration of TA were systematically investigated. Under optimal conditions, 1.5 mL extracts containing 1.6 mg mL-1 of TA was stirred with ELM at 250 r min-1 for 5 min, the extraction efficiency of target alkaloid can reach 94.14%. Finally, the method could be used in quantitative analysis of TA in herbal material and patent medicine after demulsification. By comparison, application of ELM for the enrichment and quantitation of TA offers a more straightforward and effective strategy, which is expected to provide a meaningful reference for similar separation processes.

[Surgical correction of conjunctival sac narrowing after orbital implantation using polyester fiber heart patches].

OBJECTIVE: To test the feasibility of correcting conjunctival sac narrowing following orbital implantation using polyester fiber heart patches instead of the skin autograft. METHODS: Twelve patients of conjunctival sac narrowing after orbital implantation (including 3 with orbital implant exposure) admitted in Nanfang Hospital between 2012 and 2016 received surgical correction of the conjunctival sac using polyester fiber heart patches. During the surgery, the central conjunctival sac was opened, the exposed area was covered with suitable polyester fiber heart patches, and the palpebral margin was sutured. RESULTS: Three months after the operation, 10 patients showed improved appearance after implantation of the prosthetic eye. Two patients received a second operation to remove the patches due to graft rejection and infections and skin autograft was implanted for reconstruction of the conjunctival sac. CONCLUSION: Polyester fiber heart patches are ideal materials for repairing Conjunctival sac narrowing and orbital implant exposure, but this approach is not suitable in cases of severe narrowing or occlusion of the conjunctival sac.

Thymine-functionalized amphiphilic biodegradable copolymers for high-efficiency loading and controlled release of methotrexate.

In this study, a novel thymine-functionalized six-membered cyclic carbonate monomer (TAC) was synthesized by the Michael-addition reaction between thymine and acryloyl carbonate (AC). The corresponding functional amphiphilic block copolymer mPEG-b-PTAC was further successfully synthesized by ring-opening polymerization using immobilized porcine pancreas lipase (IPPL) as the catalyst and mPEG as the macroinitiator. Meanwhile, mPEG-b-P(TAC-co-DTC) and mPEG-b-PDTC were also synthesized by the same enzymatic methods for comparison on different TAC contents. The structures of monomer and copolymers were characterized by (1)H-NMR, (13)C-NMR and FTIR. All the amphiphilic block copolymers could self-assemble to form nano-sized micelles in aqueous solution. Transmission electron microscopy (TEM) observation showed that the micelles dispersed in spherical shape with nano-size before and after MTX loading. (1)H-NMR and FTIR results confirmed the successful formation of multiple hydrogen-bonding interactions between exposed thymine groups of hydrophobic PTAC segments and 2,6-diaminopyridine (DAP) groups of MTX molecules, which resulting in the higher drug loading capacity and the pH-sensitive drug release behavior. MTT assays also indicated lower toxicity of copolymer but higher potent cytotoxic activity of MTX-loaded copolymer against HeLa cells.

A comparison of dioctahedral smectite and iodine glycerin cream with topical mouth rinse in treatment of chemotherapy induced oral mucositis: a pilot study.

PURPOSE OF THE RESEARCH: To compare the efficacy of dioctahedral smectite and iodine glycerin (DSIG) cream with topical mouth rinse (composed of saline, gentamicin and Vitamin B12) in treatment of chemotherapy induced oral mucositis (OM). METHODS AND SAMPLE: A total of 130 intensive chemotherapy or stem cells transplantation induced OM patients were recruited. Among these patients, 67 patients received topical mouth rinse and 63 patients received DSIG cream treatment. The OM would be treated on the OM appearance and sustained for 5 days. OM severity was measured daily using The American Oncology Nursing Society recommended Oral Assessment Guideline (OAG) score system. KEY RESULTS: Compared with topical mouth rinse treatment, a significant lower OAG score was observed in DSIG cream treated patients. Specifically, the OAG scores were respectively 12.1 ± 1.1, 12.0 ± 1.2, 11.3 ± 1.3 and 10.4 ± 1.3 from day 2 to day 5 in topical mouth rinse treatment subgroup. Correspondingly, the OAG scores were respectively 10.2 ± 1.0, 9.3 ± 0.9, 8.5 ± 0.6 and 8.0 ± 0.2 for DSIG cream treatment subset (all P < 0.05). Importantly, compared with topical mouth rinse treatment, the DSIG cream significantly shortened OM repair time (4.68 ± 0.98 vs. 8.76 ± 1.80 days, P < 0.001). After 5 days treatment, 54 patients (85.7%) obtained complete regression with an OAG score ≤8, and 7 patients (11.1%) had partial regression with an OAG score of 9-10 in DSIG cream treatment subgroup. However, only 2 patients (3.0%) obtained completed regression and 32 patients (47.8%) had partial regression in topical mouth rinse treatment cohort. Moreover, no serious side-effect was observed in both cohorts. CONCLUSIONS: Compared with topical mouth rinse, DSIG cream significantly lowered the OAG score and shortened OM duration.

[Effects and mechanism on removing organics and reduction of membrane fouling using granular macro-porous anion exchange resin in drinking water treatment].

A granular macro-porous anion exchange resin combined with coagulation was used as pretreatment of microfiltration membrane, and their effects and mechanism on removing organics and reduction of membrane fouling were evaluated. The results showed that resin could be effective in removing organics with medium and small molecular weight ( Mr) but ineffective in removing organics with large Mr, while couagulation could significantly remove organics with large Mr, with a limited removal for organics with medium and small Mr. Using resin alone as pretreatment could be effective in removal of organics but limited in reduction of membrane fouling. With combination of coagulation and resin as pretreatment of microfiltration, not only organics could be removed effectively, but also membrane fouling could be reduced.

[DOM membrane fouling and effects on rejection behaviors of NF membranes].

This work investigated membrane fouling caused by two kinds of dissolved organic matters (DOMs), i. e., Qingcaosha (QCS) DOM and Taihu lake (TH) DOM, and the effects on the rejection behaviors of two different nanofiltration (NF) membranes, i. e., HL and ESNA1-K, using carbamazepine (CBZ) as a molecular indicator. The results showed that severe membrane fouling occurred in the presence of DOM. And the CBZ removal rate was associated with the properties and characteristics of the organic matters and the membranes. It was found that the hydrophobicity of adhered DOM cake layer was responsible for the flux decline and the influence of CBZ removal. QCS DOM increased the retention of CBZ, while TH DOM decreased the rejection rate of CBZ by both membranes tested. DOMs at medium relative molecular weight (M(r) 1 500-10 000) could adhere closely to NF membranes to form cake layer, thus changed the hydrophobicity of the membranes. DOMs at low molecular weight could enter the membrane pores reducing the M(r), which influenced the CBZ removal and resulted in membrane fouling. The experiment also showed that DOM of TH contained more hydrophobic organic matters than that of QCS, the adhesion free energy and cohesion free energy of which was more negative, and the resulting membrane fouling and membrane flux decline were more severe.

Cloning, expression, and characterization of ß-mannanase from Bacillus subtilis MAFIC-S11 in Pichia pastoris.

The ß-mannanase gene (1,029 nucleotide) from Bacillus subtilis MAFIC-S11, encoding a polypeptide of 342 amino acids, was cloned and expressed in Pichia pastoris. To increase its expression, the ß-mannanase gene was optimized for codon usage (mannS) and fused downstream to a sequence-encoding modified α-factor signal peptide. The expression level was improved by 2-fold. This recombinant enzyme (mannS) showed its highest activity of 24,600 U/mL after 144-h fermentation. The optimal temperature and pH of mannS were 50 °C and 6.0, respectively, and its specific activity was 3,706 U/mg. The kinetic parameters V max and K m were determined as 20,000 U/mg and 8 mg/mL, respectively, representing the highest ever expression level of ß-mannanase reported in P. pastoris. In addition, the enzyme exhibited much higher binding activity to chitin, chitosan, Avicel, and mannan. The superior catalytic properties of mannS suggested great potential as an effective additive in animal feed industry.

[Effect of relative molecular mass distribution and hydrophilicity/ hydrophobicity of NOM on membrane fouling in MF-combined process].

This study investigated the reversible and irreversible foulants in a submerged microfiltration (MF) with pretreatments (coagulation/powdered activated carbon (PAC)/potassium permanganate) in a pilot scale treatment of water from Taihu Lake. The study focused on the effect of relative molecular mass (M(r)) distribution and hydrophilicity/hydrophobicity on membrane fouling using high performance size-exclusion chromatography (HPSEC) with UV and TOC detectors and three dimension fluorescence excitation-emission matrix (3DEEM). HPSEC analyses showed that pretreatments could almost completely remove the macro molecules (M(r) > 10 x 10(3)), but only eliminate part of medium (10 x 10(3)) > M(r) > 1 x 10(3)) and micro molecules (M(r) < 1 x 10(3)). A majority of medium and micro molecules were found in chemical cleaning solutions, indicating that medium and micro molecules were the main foulants that contributed to irreversible membrane fouling. In addition, it was also found that the content of strong hydrophobic acids (SHA) and neutral hydrophilic (Neut) fractions in chemical solutions were far higher than that of weakly hydrophobic acids (WHA) and charged hydrophilic (Char), which suggested that both organic fractions were responsible for irreversible fouling. 3DEEM fluorescence demonstrated that aromatic proteins and soluble microbial products were the main contributors to irreversible membrane fouling.

[Researches on factors affecting the removal of carbamazepine by nanofiltration membranes].

The influence factors on removal of carbamazepine (CBZ) in drinking water by nanofiltration membrane was mainly investigated. The effect of CBZ removal by NF270 and NF90 was firstly compared and found that removal efficiency by NF90 with small pore size showed more effectively than removed by NF270 with large pore size. The next experiment focused on the effect of various factors on removal with respect to CBZ initial concentration, pH, ionic strength and water temperature. The results showed that removal efficiency reduced with decreased pH and increased Ca2+ concentration and water temperature. The effect of initial concentration in the range of 50-500 microg/L on flux and CBZ removal was insignificant. It can be concluded that the retention of non-ionic CBZ by loose NF membrane was strongly dependent on the mechanism of steric (size) exclusion.

[Characteristic of algogenic organic matter (AOM) membrane fouling and its effect on UF membrane fouling].

Algogenic organic matter (AOM) was extracted from blue-green algae (Cyanobacteria) and its characteristics was determined by various methods including high-pressure size-exclusion chromatography (HP-SEC), hydrophobic and hydrophilic fractionation and fluorescence excitation emission matrix (EEM). The results showed that AOM was composed of hydrophilic fraction predominantly, account for 78%. The SUVA of AOM was only 1.1 L/(mg x m). The analysis for relative molecular weight (Mr) demonstrated that organic matter greater than 30,000 accounted for above 40% and mostly was composed of neutral hydrophilic compound. EEM analyses revealed that protein-like and humic substances existed in AOM. A test for membrane filtration exhibited that AOM could make ultrafiltration membrane substantial flux decline, which can be attributed to membrane pore clog caused by neutral hydrophilic compound with larger MW.

[Effect of ozone/coagulation pretreatment on membrane fouling reduction].

In order to investigate the effect of ozone and coagulation pretreatments on organic matter and MF membrane filtration, pretreated Huangpu River surface water was filtrated by MF membrane. The results showed that there were the optimal dosages of ozone and coagulant made maximum membrane flux. The result of membrane fouling reduction by coagulation was better than that by ozone, which was relative to character of organic matter removed by two pretreatment processes. Organics in Huangpu River water mostly concentrates in relative molecule mass (Mr) ranging 3 x 10(3)-5 x 10(3). Research on the chemical cleaning of the fouled membrane indicated that fouling organic substance concentrated about Mr 4.5 x 10(3). Removals of Mr 3 x 10(3) organic matter are higher than Mr 5 x 10(3) organic matter by ozone oxidation. Coagulation process can remove 5 x 10(3) high relative molecular mass organic matter effectively. Removal of these organics fouled membrane by coagulation was better than that by ozone, thereby to effectively reduce membrane fouling.

[Effect of different organic fraction on membrane flux declines].

Organic matter in the tap water was isolated into strongly hydrophobic acids, weakly hydrophobic acids, charged hydrophilic and neutral hydrophilic by DAX-8, XAD-4 and IRA-958 synthetic resins. Filtration tests using polyvinylidene fluoride (PVDF), polyethersulphone (PES) and cellulose acetate (CA) membranes were conducted to investigate the contribution of different organic fractions to membrane fouling. The results show that in filtration of raw water, flux declines with PES, PVDF and CA membrane are 67%, 59% and 19% of the initial flux, indicating that the more hydrophobic membrane resulted in more severe fouling. For the effect of different fractions on flux, flux decline with neutral hydrophilic is 41%-75% of the initial flux, whereas weakly hydrophobic acids is 6%-33%, suggesting that neutral hydrophilic has a great impact on filtration flux. Among three membranes tested, CA membrane shows the lowest flux decline compared with other membranes in spite of rejection of as high as 14.69% of neutral hydrophilic, suggesting that the extent of flux decline may not be associated with the total amount of NOM removed. The mechanism of fouling was discussed and found that the neutral hydrophilic fraction with greater than 3 x 10(4) of molecular weight caused a significant flux decline, through blocking the pore for the MF or UF having greater relative molecular mass cut-off (MWCO), but resulted in a little impact on flux with the UF having lower MWCO, through forming cake layer on the surface of membrane due to not entering the inside of pore.