Oxygen vacancies enhanced photocatalytic activity towards VOCs oxidation over Pt deposited Bi2WO6 under visible light

A novel Pt assisted self-modified Bi₂WO₆ composites (Pt/Bi-BWO) with high oxygen vacancies concentration was successfully fabricated via a simple in-situ NaBH₄ reduction method in presence of H₂PtCl₆•6H₂O. The Pt/Bi-BWO performed excellent photocatalytic activity on the degradation of gaseous toluene under visible light illumination. The photocatalytic reaction rate of 0.15% Pt/Bi-BWO was 2.88 times higher than that of Bi₂WO₆. Over 90% gas phase toluene was removed by 0.15% Pt/Bi-BWO in one hour and over 80% of which was degraded into CO₂ and H₂O. The Pt/Bi-BWO also performed great stability confirmed by circulating runs test. The mechanism of the promotion was explored by electron paramagnetic resonance (EPR) and DFT calculations. The produced oxygen vacancies were below conduction band (CB) of Bi₂WO₆, leading to a narrowed band gap. Meantime, the generated oxygen vacancies could activate O₂ to enhance the production of reactive oxygen species (ROS), such as O₂^- and OH. In addition, the added Pt could act as electron trap to suppress the recombination of electrons-holes pairs. In a word, this work produced a novel simply made photocatalyst to remove volatile organic compounds.

Copper-catalyzed 1,1-alkynylalkylation of alkynes: access toward conjugated enynes

A copper-catalyzed 1,1-alkynylalkylation of alkynes with α-haloacetamides for the construction of conjugated enynes has been developed.

Investigation of Streptococcus agalactiae using pcsB-based LAMP in milk, tilapia and vaginal swabs in Haikou, China

AIMS

To develop a pcsB-based Loop-mediated isothermal amplification (LAMP) method for the detection of Streptococcus agalactiae (GBS) in milk, tilapia and vaginal swabs.

METHODS AND RESULTS

The sensitivity of the LAMP method using real-time turbidity monitoring was 1 pg of template within 1 h at 64°C, 100-fold higher than conventional PCR. The sensitivity of visual detection dropped an order of magnitude using SYBR Green I or hydroxynaphthol blue. The validity of the visual LAMP assay was assessed by the detection of GBS in 180 vaginal swabs from one hospital, 14 brain tissues samples of diseased tilapias from two fishponds and fresh milk of 67 dairy cattle from one farm. In total, 17 samples (4 vaginal swabs, 13 tilapia brain tissues but no milk sample) tested positive for GBS. Subsequent bacterial identification confirmed the specificity and reliability of the LAMP method. Molecular serotyping and multilocus sequence typing demonstrated that all 13 tilapia GBS isolates were identical (serotype Ia, ST7), whereas the four human GBS isolates were more diverse and could be classified into two serotypes (Ia, III) and four sequence types (ST19, ST23, ST24, ST862). Virulence gene testing showed that only the bac, rib and lmb genes were not present in all isolates. Antimicrobial susceptibility profiles of the isolates were basically consistent with their genotypes, except for sulphonamide and fluoroquinolone.

CONCLUSIONS

We developed a reliable pcsB-based LAMP assay for GBS detection. Our results demonstrated that the prevalence of GBS was 92·9% among diseased tilapia, 2·2% among female patients and 0% on a dairy farm in Hainan.

SIGNIFICANCE AND IMPACT OF THE STUDY

The pcsB-based LAMP method is suitable for GBS detection and contains great potential of application in dairy industry, aquiculture and clinical.

Novel visible light enhanced Pyrite-Fenton system toward ultrarapid oxidation of p-nitrophenol: Catalytic activity, characterization and mechanism

The activities of heterogeneous Fenton and Photo-Fenton processes using pyrite (FeS₂) prepared via a solvethermal method were evaluated by oxidation of p-nitrophenol (PNP). PNP could be completely ultrarapidly oxidized by Pyrite-Photo-Fenton (Pyrite-PF) system within 4 min, versus 10 min in Pyrite-Fenton (Pyrite-F) system. The excellent oxidation performance obtained by Pyrite-PF might be due to accelerated circulation between ferrous ions and ferric ions under visible light illumination, which improved generation of reactive oxygen species (ROS). X-ray diffraction (XRD), scanning electron microscope (SEM), high resolution transmission electron microscopy (HRTEM), electron paramagnetic resonance (EPR) and X-ray photoelectron spectroscopy (XPS) were applied to ascertain the morphology and crystal structure of fresh-pyrite as well as used-pyrite. According to these results, the synthesized pyrite particles performed eminent stability, and used-pyrite could even generated more ROS including hydroxyl radicals (OH) and superoxide radicals (O₂^-). EPR testing and quenching experiments also confirmed the generations of OH, O₂^- and holes (h⁺) during oxidation processes of PNP in both Pyrite-F and Pyrite-PF systems. The reaction pathway was proposed based on the detected intermediate products including 4-nitrocatechol, 4-nitropyrogallol, hydroquinone, benzoquinone, 1,2,4-trihydroxybenzene and 2,4-dinitrophenol. The mechanisms of PNP degradation in Pyrite-F and Pyrite-PF systems have also been studied by DFT calculations. Pyrite (111) should be responsible for the generations of free OH and surface OH.

Enhanced detection of toxicity in wastewater using a 2D smooth anode based microbial fuel cell toxicity sensor

As the biological recognition element of microbial fuel cell (MFC) toxicity "shock" sensors, the electrode biofilm is perceived to be the crucial issue that determines the sensing performance. A carbon felt and indium tin oxide (ITO) film anode were utilized to examine the effects of anodic biofilm microstructure on MFC toxicity sensor performance, with Pb2+ as the target toxicant. The carbon felt anode based MFC (CF-MFC) established a linear relationship of Pb2+ concentration (C Pb2+ ) vs. voltage inhibition ratio (IR2h) at a C Pb2+ range of 0.1 mg L-1 to 1.2 mg L-1. The highest IR2h was only 38% for CF-MFC. An ITO anode based MFC (ITO-MFC) also revealed a linear relationship between C Pb2+ and IR2h at C Pb2+ of 0.1 mg L-1 to 1.5 mg L-1 but better sensing sensitivity compared with the CF-MFC. The IR2h of ITO-MFC gradually approached 100% as C Pb2+ further increased. The enhanced sensing sensitivity for the ITO anode possibly originated from the thin biofilm that resulted in the efficient exposure of exoelectrogens to Pb2+. The employment of 2D conductive metal oxide with a smooth surface as the anode was able to increase the MFC sensing reliability in real wastewater.

Three species of Aeromonas (A. dhakensis, A. hydrophila and A. jandaei) isolated from freshwater crocodiles (Crocodylus siamensis) with pneumonia and septicemia

Hundreds of farmed Siamese crocodiles (Crocodylus siamensis) died during July 2016 at a farm in Wenchang, Hainan, China. In two necropsied crocodiles, we observed symptoms of dermatorrhagia, hepatomegaly and hepatic congestion. Pulmonitis was diagnosed by pulmonary congestion and pulmonary fibrinous exudate. Septicaemia was diagnosed by isolation of three Aeromonas species from blood and visceral tissues; A. dhakensis, A. hydrophila and A. jandaei were identified by biochemical and molecular tests. We used a zebrafish model to determine the half-maximal lethal dose (LD₅₀ ), and A. dhakensis was found to be the most virulent species, with an LD₅₀ of 8·91 × 10⁵ CFU per ml. The results of a drug sensitivity test indicated that these species were sensitive to 11 antibiotics. This is the first report of A. dhakensis, A. hydrophila and A. jandaei being isolated from a mixed infection in Siamese crocodiles. SIGNIFICANCE AND IMPACT OF THE STUDY: In this study, we isolated three species of Aeromonas (A. dhakensis, A. hydrophila and A. jandae) from farmed Siamese crocodiles with fatal fibrinous pneumonia and septicaemia. This is the first description of a mixed infection with three Aeromonas species among captive crocodilians.

Activated microporous-mesoporous carbon derived from chestnut shell as a sustainable anode material for high performance microbial fuel cells

Microbial fuel cells (MFCs) are promising biotechnologies tool to harvest electricity by decomposing organic matter in waste water, and the anode material is a critical factor in determining the performance of MFCs. In this study, chestnut shell is proposed as a novel anode material with mesoporous and microporous structure prepared via a simple carbonization procedure followed by an activation process. The chemical activation process successfully modified the macroporous structure, created more mesoporous and microporous structure and decreased the O-content and pyridinic/pyrrolic N groups on the biomass anode, which were beneficial for improving charge transfer efficiency between the anode surface and microbial biofilm. The MFC with activated biomass anode achieved a maximum power density (23.6 W m^-3) 2.3 times higher than carbon cloth anode (10.4 W m^-3). This study introduces a promising and feasible strategy for the fabrication of high performance anodes for MFCs derived from cost-effective, sustainable natural materials.

Utilization of anaerobic granular sludge for chromium (VI) removal from wastewater: optimization by response surface methodology

In this study, anaerobic granular sludge (AGS) was used as a novel adsorbent for hexavalent chromium (Cr (VI)) removal from aqueous solutions. Factor experiments were conducted to find out the effects of different variables on the biosorption process. Among these terms, the impact of three main independent variables (contact time, initial pH and AGS dosage) on the removal efficiency of Cr (VI) was modeled using a well-fitting polynomial equation (R² = 0.9044), by conducting 20 batch experiments designed by a central composite. The experimental isotherm data were successfully described by the Freundlich isotherm and the pseudo-second-order kinetic model was more suitable for explaining the kinetics process of adsorption. The AGS can be disposed using 0.1 M NaOH with 96.4% desorption efficiency. The results of the analyses (X-ray photoelectron spectroscopy and Fourier transformed infrared spectroscopy) suggested that Cr (VI) adsorption most likely involved electrostatic adsorption, redox reaction and complexation.

[Long-term outcomes after cataract surgery in infants with congenital cataract]

Objective: To observe the long-term outcomes after congenital cataract surgery performed prior to 36 months of age. Methods: A retrospective case study was conducted. Thirty-two cases (57 eyes) of congenital cataract were included from January 2004 to January 2012. All patients received intraocular lens (IOL) implantation with posterior continuous curvilinear capsulorhexies and anterior vitrectomy after cataract extraction and were followed up. At the last visit, the best corrected visual acuity (BCVA) was determined and postoperative complications were evaluated during follow-up with a longest time of 13 years. Non-normal distribution showed in median M (minimum and maximum). Data were analyzed by Kruskal Wallis single factor variance analysis and multiple comparison. The independent Mann-Witney U test was used to analyze non-normal distribution data. Results: There were thirty-two cases (57 eyes) of congenital cataract including 7 unilateral cases and 25 bilateral cases. The median age at cataract extraction was 6.0months; the median IOL implantation age was 28.0 months and the median duration of follow-up after cataract extraction was 67.0 months. The median postoperative BCVA was (LogMAR) 0.52. Unilateral and bilateral cataract postoperative BCVA difference had no statistical significance (U=107, P>0.05). Patients received cataract surgery in 2 to 4 months, the postoperative BCVA was better than in 5 to 8 months. The difference was statistical significance (H=-15.33, P<0.05). BCVA after IOL implantation before 24 months were significantly better than after 30 months. The difference had statistical significance(H=-20.61,-20.78, P<0.05). Postoperative complications were posterior capsular opacity (5 eyes; 8.77%), glaucoma (2 eyes; 3.51%), strabismus (17 eyes; 29.82%) and nystagmus (30 eyes; 52.63%). Conclusions: Most infantile cataract surgeries performed prior to 36 mouths of life together with the implantation of IOL can achieve good visual acuity. No serious complications occurred. (Chin J Ophthalmol, 2017, 53: 266-273).

Aerobic granular sludge inoculated microbial fuel cells for enhanced epoxy reactive diluent wastewater treatment

Microbial consortiums aggregated on the anode surface of microbial fuel cells (MFCs) are critical factors for electricity generation as well as biodegradation efficiencies of organic compounds. Here in this study, aerobic granular sludge (AGS) was assembled on the surface of the MFC anode to form an AGS-MFC system with superior performance on epoxy reactive diluent (ERD) wastewater treatment. AGS-MFCs successfully shortened the startup time from 13d to 7d compared to the ones inoculated with domestic wastewater. Enhanced toxicity tolerance as well as higher COD removal (77.8% vs. 63.6%) were achieved. The higher ERD wastewater treatment efficiency of AGS-MFC is possibly attributed to the diverse microbial population on MFC biofilm, as well as the synergic degradation of contaminants by both the MFC anode biofilm and AGS granules.

Failed cooperative, but not competitive, interaction between large-scale brain networks impairs working memory in schizophrenia

BACKGROUND

A large-scale network named the default mode network (DMN) dynamically cooperates and competes with an external attention system (EAS) to facilitate various cognitive functioning that is prominently impaired in schizophrenia. However, it is unclear whether the cognitive deficit in schizophrenia is related to the disrupted competition and/or cooperation between these two networks.

METHOD

A total of 35 schizophrenia patients and 30 healthy controls were scanned using gradient-echo echo-planar imaging during n-back working memory (WM) processing. Brain activities of the DMN and EAS were measured using general linear modelling of the functional magnetic resonance imaging data. Dynamic interaction between the DMN and EAS was decomposed into two directions using Granger causality analysis.

RESULTS

We observed a significant failure of DMN suppression in patients with schizophrenia, which was significantly related to WM/attentional deficit. Granger causality modelling showed that in healthy controls, while the EAS inhibitorily influenced the DMN, the DMN exerted an 'excitatory' or cooperative influence back on the EAS, especially in those with lower WM accuracy. In schizophrenia, this 'excitatory' DMN→EAS influence within the reciprocal EAS-DMN loop was significantly reduced, especially in patients with WM/attentional deficit.

CONCLUSIONS

The dynamic interaction between the DMN and EAS is likely to be comprised of both competitive and cooperative influences. In healthy controls, both the 'inhibitory' EAS→DMN interaction and 'excitatory' DMN→EAS interaction are correlated with WM performance. In schizophrenia, reduced 'cooperative' influence from the DMN to dorsal nodes of the EAS occurs in the context of non-suppression of the DMN and may form a possible pathophysiological substrate of WM deficit and attention disorder.

Influence of deposition substrate temperature on the morphology and molecular orientation of chloroaluminum phthalocyanine films as well the performance of organic photovoltaic cells

The dependence of the morphology of neat chloroaluminum phthalocyanine (ClAlPc) films on substrate temperature (Tsub) during deposition is investigated by variable angle spectroscopic ellipsometry (VASE), x-ray diffraction (XRD), and atomic force microscopy (AFM) to obtain detailed information about the molecular orientation, phase separation, and crystallinity. AFM images indicate that both grain size and root mean square (RMS) roughness noticeably increase with Tsub both in neat and blend films. Increasing Tsub from room temperature to 420 K increases the horizontal orientation of the ClAlPc molecules with an increase of the mean molecular tilt angle from 60.13° (300 K) to 65.86° (420 K). The UV-vis absorption band of the corresponding films increases and the peak wavelength slightly red shifts with the Tsub increase. XRD patterns show a clear diffraction peak at Tsub over 390 K, implying the π-stacking of interconnected ClAlPc molecules at high Tsub. Planar and bulk heterojunction (BHJ) photovoltaic cells containing pristine ClAlPc films and ClAlPc:C60 blend films fabricated at Tsub of 390 K show increases in the power conversion efficiency (ηPCE) of 28% (ηPCE = 3.12%) and 36% (ηPCE = 3.58%), respectively, relative to devices as-deposited at room temperature. The maximum short circuit current in BHJs is obtained at 390 K in the Tsub range from 300 K to 450 K.

Removal of benzotriazole by heterogeneous photoelectro-Fenton like process using ZnFe2O4 nanoparticles as catalyst

ZnFe2O4 nanoparticles (ZFNPs) were developed as catalyst for the degradation of benzotriazole (BTA) by heterogeneous photoelectro-Fenton (PE-Fenton) like process. ZFNPs were prepared by a co-precipitation process and then characterized with transmission electron microscopy (TEM), X-ray fluorescence (XRF), X-ray diffraction (XRD) and BET surface area. Using such ZFNPs as catalyst, the degradation of BTA was investigated. Due to the high catalytic activity of ZFNPs, PE-Fenton like process showed efficient degradation of BTA. The influencing factors such as pH, dosage of ZFNPs, applied potential and initial concentration of BTA were systematically investigated. Under the optimum conditions, 91.2% of BTA was removed after 180 min treatment.

Simulation of the performance of aerobic granular sludge SBR using modified ASM3 model

The activated sludge model No. 3 (ASM3) was modified to describe the biological reactions in aerobic granular sludge SBR. The simultaneous storage and growth, nitrification and denitrification were all accounted for in modified model. The sensitivities of effluent COD, NH(4)(+) -N, and TN toward the stoichiometric and kinetic coefficients were analyzed. A standard set of parameters obtained from a combination of literature data was chosen for the model. The experimental results for the time profile of COD, NH(4)(+) -N, and TN in a typical cycle were used to verify the ASM3 model. The verification results show the model established is applicable for simulating the perfo rmance of an aerobic granule-based SBR. A comparison of the measured and predicted values of substrate removal for both the modified ASM3 and the original ASM3 was also performed. The verification and comparison results show the modified ASM3 model describes the aerobic granule-based SBR better and more mechanistically.

Stable aerobic granules in continuous-flow bioreactor with self-forming dynamic membrane

A novel continuous-flow bioreactor with aerobic granular sludge and self-forming dynamic membrane (CGSFDMBR) was developed for efficient wastewater treatment. Under continuous-flow operation, aerobic granular sludge was successfully cultivated and characterized with small particle size of about 0.1-1.0mm, low settling velocity of about 15-25 m/h, loose structure and high water content of about 96-98%. To maintain the stability of aerobic granular sludge, strategies based on the differences of settling velocity and particle-size between granular and flocculent sludge were implemented. Moreover, in CGSFDMBR, membrane fouling was greatly relieved. Dynamic membrane was just cleaned once in more than 45 days' operation. CGSFDMBR presented good performance in treating septic tank wastewater, obtaining average COD, NH(4)(+)-N, TN and TP removal rates of 83.3%, 73.3%, 67.3% and 60%, respectively, which was more efficient than conventional bioreactors since that carbon, nitrogen and phosphorus were simultaneously removed in a single aerobic reactor.

Feasibility investigation of oily wastewater treatment by combination of zinc and PAM in coagulation/flocculation

Poly-zinc silicate (PZSS) is a new type of coagulant with cationic polymer synthesized by polysilicic acid and zinc sulfate. It has been used in several sorts of wastewaters treatment, but not used in oily wastewater treatment. In this study, we investigated the coagulation/flocculation of oil and suspended solids in heavy oil wastewater (HOW) by PZSS and anion polyacrylamide (A-PAM). The properties of PZSS cooperated with A-PAM were compared with PAC and PFS in dosages, PAMs amount, settling time, pH value and flocs morphology. The results showed that PZSS was more efficient than PAC and PFS. Under the optimum experimental conditions of coagulation/flocculation (dosage: 100mg/L, A-PAM dosage: 1.0mg/L, settling time time: 40min and pH 6.5-9.5), more than 99% of oil was removed and suspended solid value less than 5mg/L by using PZSS cooperated with A-PAM, which could satisfy the demands of the pre-treatment process for HOW to be reused in the steam boiler or recycled into the injecting well.

Chaperoning of estrogen receptor and induction of mammary gland proliferation by neuronal protein synuclein gamma

Synucleins are emerging as central players in the formation of pathologically insoluble deposits characteristic of neurodegenerative diseases. However, synuclein gamma (SNCG), previously identified as a breast cancer specific gene (BCSG1), is also highly associated with breast cancer progression. Using transgenic mouse model, we demonstrated a role of SNCG in induction of highly proliferative pregnancy-like phenotype of mammary epithelial cells and branching morphology. SNCG participated in the heat shock protein-based multiprotein chaperone complex for steroid receptor signaling. Expression of SNCG in mammary epithelium resulted in a significant stimulation of ERalpha transcriptional activity. SNCG-induced mammary gland proliferation can be effectively blocked by antiestrogen and ovariectomy, indicating that the induced proliferation is mediated by ERalpha signaling and requires estrogen stimulation. These data indicate the chaperone activity of SNCG on stimulation of steroid receptor signaling in mammary gland and, thus induces extensive mammary gland proliferation and contributes to the hormonal impact on mammary tumorigenesis.

Evaluation of the role of I(KACh) in atrial fibrillation using a mouse knockout model

OBJECTIVES

We sought to study the role of I(KACh) in atrial fibrillation (AF) and the potential electrophysiologic effects of a specific I(KACh) antagonist.

BACKGROUND

I(KACh) mediates much of the cardiac responses to vagal stimulation. Vagal stimulation predisposes to AF, but the specific role of I(KACh) in the generation of AF and the electrophysiologic effects of specific I(KACh) blockade have not been studied.

METHODS

Adult wild-type (WT) and I(KACh)-deficient knockout (KO) mice were studied in the absence and presence of the muscarinic receptor agonist carbachol. The electrophysiologic features of KO mice were compared with those of WT mice to assess the potential effects of a specific I(KACh) antagonist.

RESULTS

Atrial fibrillation lasting for a mean of 5.7+/-11 min was initiated in 10 of 14 WT mice in the presence of carbachol, but not in the absence of carbachol. Atrial arrhythmia could not be induced in KO mice. Ventricular tachyarrhythmia could not be induced in either type of mouse. Sinus node recovery times after carbachol and sinus cycle lengths were shorter and ventricular effective refractory periods were greater in KO mice than in WT mice. There was no significant difference between KO and WT mice in AV node function.

CONCLUSIONS

Activation of I(KACh) predisposed to AF and lack of I(KACh) prevented AF. It is likely that I(KACh) plays a crucial role in the generation of AF in mice. Specific I(KACh) blockers might be useful for the treatment of AF without significant adverse effects on the atrioventricular node or the ventricles.

[Diagnostic and differential diagnostic potential of mitochondrial DNA assessment in patients with Leber's hereditary optic neuropathy]

OBJECTIVE

To study the primary mutations of mitochondrial DNA (mtDNA) associated with Leber's hereditary optic neuropathy (LHON) in patients with optic neuropathy.

METHODS

Seventy-nine patients with a variety of bilateral optic neuropathy were examined. Mutations at np 3,460, np 11,778 and np 14,484 of mtDNA were tested by PCR-restriction fragment length polymorphism technique to detect DNA in peripheral blood. The samples were taken from 16 cases of clinically diagnosed LHON, 44 cases of suspected LHON, two cases of alcohol amblyopia, four cases of multiple sclerosis, five cases of autosomal dominant hereditary optic atrophy, 4 cases with primary open-angle glaucoma, three cases of spinocerebellar degeneration, and one case of ethambutol-induced optic neuropathy.

RESULTS

The mutation at np 11,778 was identified in 31 cases (39.2%), consisting of all the 16 clinically diagnosed LHON cases, thirteen cases (29.5%) of the suspected LHON, and the two cases of alcohol amblyopia. The remaining 48 cases were negative for mtDNA mutations at np 3,460, np 11,778, or np 14,484.

CONCLUSION

Assessment of mtDNA provides a useful diagnostic aid in confirming and excluding the diagnosis of LHON, particularly useful in cases without a family hereditary history and cases with cause unknown bilateral optic neuritis.

Diagnostic potential of mitochondrial DNA assessment in patients with optic neuropathy

OBJECTIVE

To study the primary mutations of mitochondrial DNA (mtDNA) associated with Leber's hereditary optic neuropathy (LHON) in patients with optic neuropathy.

METHODS

Seventy-nine patients with a variety of bilateral optic neuropathies were examined. Mutations at np3460, np11,778 and np14,484 of mtDNA were tested by PCR-restriction detection in peripheral blood DNA from 16 cases of clinically probable LHON, 44 cases of possible LHON, 2 cases of alcohol amblyopia, 4 cases of multiple sclerosis, 5 cases of autosomal dominant optic atrophy, 4 cases of primary open-angle glaucoma, 3 cases of spinocerebellar degeneration, and 1 case of ethambutol-induced optic neuropathy.

RESULTS

The mutation at np11778 was identified in 31 cases (39.2%) to establish LHON, which consisted of: all 16 of clinically probable LHON cases, 13 cases (29.5%) of possible LHON, and 2 cases of alcohol amblyopia. The remaining 48 cases were negative for mtDNA mutations at np3460, np11 778, and np14,484.

CONCLUSION

Assessment of mtDNA provides a useful diagnostic aid in the definition and exclusion of LHON, in particular family history-negative, otherwise undefined bilateral optic nerve inflammatory disease.

pICln binds to a mammalian homolog of a yeast protein involved in regulation of cell morphology

Since its cloning and tentative identification as a chloride channel, the function of the pICln protein has been debated. Although there is no consensus regarding the specific function of pICln, it was suggested to play a role, directly or indirectly, in the function of a swelling-induced chloride conductance. Previously, the protein was shown to exist in several discrete protein complexes. To determine the function of the protein, we have begun the systematic identification of all proteins to which it binds. Here we show that four proteins firmly bind to pICln and identify the 72-kDa pICln-binding protein by affinity purification and peptide microsequencing. The interaction between this protein and pICln was verified several ways, including the extraction of several pICln clones from a cDNA library using the 72-kDa protein as a bait in a yeast two-hybrid screen. The protein is homologous to the yeast Skb1 protein. Skb1 interacts with Shk1, a homolog of the p21(Cdc42/Rac)-activated protein kinases (PAKs). The known involvement of PAKs in cytoskeletal rearrangement suggests that pICln may be linked to a system regulating cell morphology.

[An experimental study on effects of biomembrane on prevention of filtering bleb adhesion in trabeculectomy]

OBJECTIVE

The study was designed to investigate the effects of biomembrane on experimental trabeculectomy.

METHODS

A biomembrane was implanted under the scleral flap and the conjunctival flap in trabeculectomy in one eye of rabbits, while the fellow eye of the same rabbit without biomembrane implantation was the control.

RESULTS

(1) The wound healing of the procedure reached its peak at 2-3 weeks after surgery, while the absorption of the biomembrane began at 6 weeks after surgery, and there was no tight adhesion between the biomembrane and the scar tissue, thus the filtering fistula was prevented from obstruction. (2) From the 2nd to the 7th week after surgery, the percentage of existing functional bleb in the experimental group was significantly higher than that in the control group (P < 0.05). (3) From the 1st to the 5th postoperative week, the decreasing of intraocular pressure in the experimental group was significantly greater than that in the control group (P < 0.05).

CONCLUSION

The use of biomembrane in trabeculectomy can prevent the adhesion of filtering bleb and decrease intraocular pressure more effectively, and this study can provide experimental reference for the clinical use of biomembrane.

Effects of pH and sulfhydryl specific reagents on 4-fumarylacetoacetate fumarylhydrolase

The pH-dependence of fumarylacetoacetase (4-fumarylacetoacetate fumaryl-hydrolase, EC 3.7.1.2) activity was studied in the pH range 6.25-8.50. After correction of the substrate concentration for enolate formation, the Michealis constant was found to be pH independent in this range. Likewise, the Ki values for the competitive inhibitors chloride and fluoride were found to be independent of pH between 6.25-8.50. A bell-shaped curve described the log V vs. pH dependence, and ionization constants of 6.5 and 8.2 were calculated. Tentatively an imidazole group and a sulfhydryl group were assigned to the constants 6.5 and 8.2, respectively. Both p-hydroxymercuribenzoate and 5,5'-dithiobis(2-nitrobenzoic acid) react with both sulfhydryl groups per subunit in the native protein and three sulfhydryl groups per subunit in the denatured protein. Substrate protects one sulfhydryl group in the native protein from reaction with 5,5'-dithiobis(2-nitrobenzoid acid). Substrate or the competitive inhibitor, fluoride, protect the enzyme from inactivation by p-hydroxymercuribenzoate. In addition p-hydroxymercuribenzoate shows saturation kinetics. Neither sulfhydryl inhibitor completely inactivates the enzyme. The enzyme is described as having three sulfhydryl groups per subunit, one of which is inaccessible to the sulfhydryl specific reagents when the protein is in the native state. One of the two accessible sulfhydryl groups is either near the active site or essential in maintaining the structure of the protein.