Fungal laccase: copper induction, semi-purification, immobilization, phenolic effluent treatment and electrochemical measurement

The laccase activity induced by copper ions in Trametes versicolor by two inducers was studied and the aims were to show that it is possible to obtain a high laccase activity in almost 12 of the enzymesproduct using a basic culture medium but different copper concentration. Laccase was inducted by 2,5-xylidine and copper sulfate. Semi-purification of the crude laccase was carried out through precipitation and the column separation with NaCl gradient. In order to apply in an effluent treatment, laccase was immobilized on different vitroceramics supports, pyrolytic graphite and also on a carbon fiber electrode as biosensor. The maximum laccase activity was 40,774.0 U L-1 at the 12th day. The best support for immobilization was pyrolytic graphite (glutaraldehyde treated-94% efficiency). Total phenol removal in Kraft E1 effluent was 19% for immobilized pyrolytic graphite with the mediator present. The biosensor prepared with this material showed a good linear response to catechol. The optimization of laccaseactivity induction through the combination of 2,5-xylidine and cooper sulfate was obtained and led to its use in environmental remediation

Characterization of Cholinesterases in Plasma of Three Portuguese Native Bird Species: Application to Biomonitoring

Over the last decades the inhibition of plasma cholinesterase (ChE) activity has been widely used as a biomarker to diagnose organophosphate and carbamate exposure. Plasma ChE activity is a useful and non-invasive method to monitor bird exposure to anticholinesterase compounds; nonetheless several studies had shown that the ChE form(s) present in avian plasma may vary greatly among species. In order to support further biomonitoring studies and provide reference data for wildlife risk-assessment, plasma cholinesterase of the northern gannet (Morus bassanus), the white stork (Ciconia ciconia) and the grey heron (Ardea cinerea) were characterized using three substrates (acetylthiocholine iodide, propionylthiocholine iodide, and S-butyrylthiocholine iodide) and three ChE inhibitors (eserine sulphate, BW284C51, and iso-OMPA). Additionally, the range of ChE activity that may be considered as basal levels for non-exposed individuals was determined. The results suggest that in the plasma of the three species studied the main cholinesterase form present is butyrylcholinesterase (BChE). Plasma BChE activity in non-exposed individuals was 0.48±0.11 SD U/ml, 0.39±0.12 SD U/ml, 0.15±0.04 SD U/ml in the northern gannet, white stork and grey heron, respectively. These results are crucial for the further use of plasma BChE activity in these bird species as a contamination bioindicator of anti-cholinesterase agents in both wetland and marine environments. Our findings also underscore the importance of plasma ChE characterization before its use as a biomarker in biomonitoring studies with birds

Induction, expression and characterisation of laccase genes from the marine-derived fungal strains Nigrospora sp. CBMAI 1328 and Arthopyrenia sp. CBMAI 1330

The capability of the fungi Nigrospora sp. CBMAI 1328 and Arthopyrenia sp. CBMAI 1330 isolated from marine sponge to synthesise laccases (Lcc) in the presence of the inducer copper (110 M) was assessed. In a liquid culture medium supplemented with 5 M of copper sulphate after 5 days of incubation, Nigrospora sp. presented the highest Lcc activity (25.2 UL1). The effect of copper on Lcc gene expression was evaluated by reverse transcriptase polymerase chain reaction. Nigrospora sp. showed the highest gene expression of Lcc under the same conditions of Lcc synthesis. The highest Lcc expression by the Arthopyrenia sp. was detected at 96 h of incubation in absence of copper. Molecular approaches allowed the detection of Lcc isozymes and suggest the presence of at least two undescribed putative genes. Additionally, Lcc sequences from the both fungal strains clustered with other Lcc sequences from other fungi that inhabit marine environments.M. Passarini was supported by Ph.D. grant from FAPESP (2008/06720-7), Sao Paulo, Brazil. The authors thank FAPESP for financial support (BIOTA-FAPESP grant 2010/50190-2 and FAPESP grant 2013/19486-0) and Roberto G.S. Berlinck and CEBIMAR for the support related to samples collecting. L.D. Sette thanks CNPq for Productivity Fellowships 304103/2013-6

Evaluation of a new community-based curriculum in disaster medicine for undergraduates

BACKGROUND: Nowadays, many medical schools include training in disaster medicine in undergraduate studies. This study evaluated the efficacy of a disaster medicine curriculum recently designed for Saudi Arabian medical students. METHODS: Participants were 15 male and 14 female students in their fourth, fifth or sixth year at Jazan University Medical School, Saudi Arabia. The course was held at the Research Center in Emergency and Disaster Medicine and Computer Sciences Applied to the Medical Practice in Novara, Italy. RESULTS: The overall mean score on a test given before the course was 41.0 % and it increased to 67.7 % on the post-test (Wilcoxon test for paired samples: z = 4.71, p < 0.0001). There were no significant differences between the mean scores of males and females, or between students in their fourth, fifth or sixth year of medical school. CONCLUSIONS: These results show that this curriculum is effective for teaching disaster medicine to undergraduate medical students. Adoption of this course would help to increase the human resources available for dealing with disaster situations

Antibacterial Activity Of Chitosan Solutions For Wound Dressing

Chitosan has found wide application in the biomedical field due to its interesting biological properties that include: biocompatibility, biodegradability, hemostatic activity and bacteriostatic effect. In this present study, antibacterial activity of chitosan solutions for wound dressing were investigated against Stophylococcus aureus (isolated from an activated sludge) and Escherichia coli (ATCC 25922) that are potential wound pathogens. Moreover, the effects of plasticizer addition and chitosan concentration on antibacterial activity of chitosan solutions were also evaluated. According to the antibacterial activity study, chitosan solutions, plasticized or not, showed inhibitory activity against Escherichia coli. However, they did not inhibit Staphylococcus aureus growth, possibly because this bacterium strain would become resistant due to mutations caused by industrial effluent exposure. Copyright © 2006 WILEY-VCH Verlag GmbH & Co. KGaA.245-246515518Kurita, K., (1998) Polym. Degrad Stabil, 59, p. 117Berger, J., (2004) Eur. J. Pharm. Biopharm, 57, p. 19Hoemann, C., (2005) Osteoarthr. Cartilage, 13, p. 318Denkbas, E., (2004) J. Biomater. Appl, 18, p. 291Ueno, H., (2001) Adv. Drug Deliver Rev, 52, p. 105Helander, I.M., (2001) Int. J. Food Microbiol, 71, p. 235Bowler, P.C., (2001) Clin. Microbiol. Rev, 14, p. 244Uri, J.V., (1994) Acta Microbiol. Immunol. Hung, 41 (2), p. 215Suyatma, N., (2005) J. Agr. Food Chem, 53, p. 3950Liu, H., (2004) Int. J. Food Microbiol, 95 (2), p. 14

Bacterial Remediation From Effluent Containing Multi-walled Carbon Nanotubes

Multi-wall carbon nanotubes (MWCNT) were functionalized with functional groups containing oxygen, mainly carboxylic groups (-COOH), through reaction with a mixture of H2SO4/HNO3 (3:1 v/v). The oxidized multi-wall carbon nanotubes (MWCNTOOH) were used to prepare an effluent, 2 mg L-1 in a saline solution of NaCl (0.9%), to study of remediation of MWCNTOOH in aqueous suspension by utilization of Escherichia coli. The suspensions of E. coli (4.5 × 105 CFU mL-1 and 4.5 × 108 CFU mL-1) in test tubes with MWCNTOOH effluent caused the precipitation of a large amount of MWCNTOOH and supernatant clearing. The scanning electron microscopy (SEM) analysis of the precipitate and supernatant showed the adhesion and interlace of MWCNTOOH in bacteria surface. Although the precipitate consist of a large quantity of MWCNTOOH and bacteria, it was verified their presence in the supernatant. The spread plate technique showed that MWCNTOOH caused no cellular death of E. coli in the supernatant.3041Baughman, R.H., Zakhidov, A.A., De Heer, W.A., Carbon nanotubes the route toward applications (2002) Science, 297, p. 787Kang, S., Pinault, M., Pfefferle, L.D., Elimelech, M., Single-Walled Carbon Nanotubes Exhibit Strong Antimicrobial Activity (2007) Langmuir, 23, p. 8670Lam, C.W., James, J.T., McCluskey, R., Arepalli, S., Hunter, R.L., A review of carbon nanotube toxicity and assessment of potential occupational and environmental health risks (2006) Crit. Rev. Toxicol., 36, p. 189Jia, G., Wang, H., Yan, L., Wang, X., Pei, R., Yan, T., Zhao, Y., Guo, X., Cytotoxicity of Carbon Nanomaterials: Single-Wall Nanotube, Multi-Wall Nanotube, and Fullerene (2005) Environ. Sci. Technol., 39, p. 1378Moon, H.M., Kim, J.W., Carbon Nanotube Clusters as Universal Bacterial Adsorbents and Magnetic Separation Agents (2010) Biotechnol. Prog.r, 26, p. 179Gu, L., Elkin, T., Jiang, X., Li, H., Lin, Y., Qu, L., Tzeng, T.R.J., Sun, Y.P., Single-walled carbon nanotubes displaying multivalent ligands for capturing pathogens (2005) Chem. Commun., 7, p. 874Arias, L.R., Yang, L., Inactivation of Bacterial Pathogens by Carbon Nanotubes in Suspensions (2009) Langmuir, 25, pp. 3003-3012Akasaka, T., Watari, F., Capture of bacteria by flexible carbon nanotubes (2009) Acta Biomateralia, 5, p. 607Tan, H., Jiang, L.Y., Huang, Y., Liu, B., Hwang, K.C., The effect of van der Waals-based interface cohesive law on carbon nanotube-reinforced composite materials (2007) Compos. Sci. Tech., 67, p. 2941Kang, S., Herzberg, M., Rodrigues, D.F., Elimelech, M., Antibacterial Effects of Carbon Nanotubes: Size Does Matter! (2008) Langmuir, 24, p. 640