Performance of a narrow buffer strip in abating agricultural pollutants in the shallow subsurface water flux

The performance of a narrow buffer strip in abating dissolved P, electrical conductivity and herbicides (terbuthylazine, alachlor, nicosulfuron, pendimethalin, linuron) in subsurface water coming from cropland was tested in an experiment carried out on the low plains of the Veneto Region (NE Italy). The experiment lasted from December 1997 to June 1999, monitoring subsurface water quality entering and exiting a buffer composed of a grass strip (5 m wide) and 1 m wide row of trees. Dissolved phosphorus concentrations were reduced by almost 100% passing through the buffer and in most cases exiting water satisfied the limit for avoiding eutrophication. A positive effect was also detected on ECW (reduced by 20%), while pH was not significantly altered. Herbicide concentration abatement varied between 60 and 90%, depending on chemical and time elapsed since application

Encapsulation of N,N-diethyl-meta-toluamide (DEET) via miniemulsion polymerization for temperature controlled release

N,N-diethyl-meta-toluamide (DEET), an insect repellent, can be successfully encapsulated in poly(n-butyl methacrylate-co-methyl methacrylate) nanospheres via direct miniemulsion polymerization. Stable and low polydisperse nanospheres with a number average diameter of 114 +/- 37nm were obtained. It is shown that DEET is an effective costabilizer and that sodium lauryl sulfate is a suitable surfactant. The nanospheres glass-transition temperature (T-g) can be tuned by adjusting the ratio between n-butyl methacrylate and methyl methacrylate in the monomer formulation. The repellent reduced the polymerization reaction rate and the copolymer molecular weight, and changed the nanoparticle morphology. The release rate of the encapsulated DEET provides repellency for over 9 h and is and more controlled when compared to the free DEET. Results show the mechanism of release is temperature dependent. At temperatures close to and lower than the polymer T-g, polymer relaxation is the limiting mechanism. At higher temperatures, Fickian diffusion limits the overall release. Thus, the DEET release rate can be tuned by adjusting the copolymer T-g. This ensures this material a great potential as temperature-dependent delivery system1369FAPESP – Fundação de Amparo à Pesquisa Do Estado De São Paulo2016/13427‐

Synthesis, purification and characterization of human ciliary neurotrophic factor from E.Coli

The cDNA for human ciliary neuronotrophic factor (CNTF) has been cloned into an expression vector under the control of the T7 promoter. The BL21 strain of E. coli was transformed with this vector. Human CNTF accounted for about 30% of the total bacterial protein after induction with isopropyl-B-D-thiogalactopyranoside. This human CNTF was purified to homogeneity from inclusion bodies by a combination of ion exchange chromatography and reverse-phase high performance liquid chromatography. The amino-terminal amino acid sequence of the purified protein was identical to the deduced amino acid sequence; however, the methionyl residue has been removed. On SDS-PAGE gels, human CNTF displayed a molecular weight of about 24 kDa, in accord with its deduced molecular mass; a pI of 5.8 indicates the acidic nature of the molecule. A proposed structure for human CNTF includes major alpha helical regions. The ED50 of purified human CNTF was approximately 30 pM, using cultured embryonic day 10 chicken dorsal root ganglion neurons; no activity was observed with neurons from embryonic day 8 ganglia. Polyclonal antibodies prepared against both a synthetic peptide of CNTF and the entire human CNTF protein recognized a single 24 kDa band on Western blots, corresponding to human CNTF. However, only the antibodies against intact CNTF blocked its biological activity. This represents the first molecular expression and purification of human CNT

Expression of biologically active human beta nerve growth factor in Escherichia coli

The gene (NGFB) encoding the beta subunit of mature human nerve growth factor (hNGFB) was subcloned into the pJLA503 expression vector under the control of bacteriophage promoters PR and PL, and expressed in Escherichia coli. The recombinant protein represented approximately 3% of the total cellular protein. Biologically active hNGFB was solubilized (0.2% total NGFB) and purified by cation-exchange chromatography and it yielded two bands on polyacrylamide-gel electrophoresis under nonreducing conditions, corresponding to the monomeric (14 kDa) and homodimeric (26.5 kDa) forms of the molecule. Both hNGFB forms were immunopositive on Western blots with rabbit anti-NGFB antibodies; however, following additional purification, only the species corresponding to the hNGFB homodimer was biologically active on cultured chicken dorsal root ganglion neurons. These results demonstrate the feasibility of synthesizing the biologically active form of hNGFB in E. coli