Luciano Cellai - Academia.edu (original) (raw)
Papers by Luciano Cellai
2006 5th IEEE Conference on Sensors, 2006
We report on the innovative electrical detection of biological binding, based on a thin metal oxi... more We report on the innovative electrical detection of biological binding, based on a thin metal oxide (MOX) film as channel for a field effect transistor. The working principle relies on modulation of a MOX space charge region (SCR) instead of an enriched/depleted Si channel like in chem-FETs. The feasibility of the working principle was at first demonstrated by pH measurement in liquid. Afterwards we implemented a reliable protocol for the immobilization of ODNs and for the electrical detection of their hybridization. Work is in progress to scale MOX down to nanosized nanowire.
Biomolecular Engineering, 2007
Carboxylic terminated monolayers have been covalently attached on phosphorous doped crystalline (... more Carboxylic terminated monolayers have been covalently attached on phosphorous doped crystalline (1 0 0) silicon surfaces using a cathodic electro grafting technique. The functionalization concentration and efficiency have been evaluated with different techniques. In particular, topographic images, performed with an atomic force microscope, were used to optimize the protocol in order to obtain a surface whose characteristics of uniformity and reproducibility are ideal for a bio-electronic device. Phase lag images of the functionalized surfaces were also performed, and show non-topographic structures that have been interpreted as areas of different molecule self-orientation. Poly-thymine oligonucleotides have been anchored on such a surface to form a nano-biosensing device capable to react selectively with a specific target molecule, a poly-adenine oligonucleotide. AFM images of high density ($3 Â 10 12 mol/cm 2) single strand and double strand covered samples show toroidal shaped structures formed by the self-assembly of the oligonucleotides on the silicon surface.
Antiviral chemistry & chemotherapy, 1999
A series of chemically oversulphated galactosaminoglycans (SO3H:COOH ratio > or = 2) were test... more A series of chemically oversulphated galactosaminoglycans (SO3H:COOH ratio > or = 2) were tested in vitro as antiviral agents against human immunodeficiency virus type 1 (HIV-1), the aetiological agent of AIDS, and against herpes simplex virus type 1 and human cytomegalovirus, two agents responsible for opportunistic infections in HIV-infected people. The oversulphated derivatives displayed an increase in activity ranging from one to four orders of magnitude against the three viruses, as compared to the natural parent compounds (SO3H:COOH, ratio approx. 1). The antiviral activity of these polyanions appears to be favoured by a high degree of sulphation and a high molecular mass. An oversulphated dermatan, with a SO3H:COOH ratio of 2.86 and molecular mass of 23.2 kDa, was the most potent anti-HIV-1 compound (EC50 0.04 microgram/ml). A second oversulphated dermatan, with a SO3H:COOH ratio of 2.40 and molecular mass of 25 kDa, displayed the highest activity against HSV-1 (EC50 0.01 ...
Chembiochem, Jan 25, 2010
Inflammation, Sep 1, 1997
Http Dx Doi Org 10 1080 15257770008033053, Sep 24, 2006
Journal of Medicinal Chemistry, Jul 10, 1992
International Journal of Pharmaceutics, 1996
Engineering in Translational Medicine, 2013
Journal of Medicinal Chemistry, 1992
European Journal of Medicinal Chemistry, 1989
Bioorganic & Medicinal Chemistry, 2008
Journal of Medicinal Chemistry, 1992
CHEMICAL & PHARMACEUTICAL BULLETIN, 2000
The synthesis of a series of diacetylenic compounds related to the natural product falcarindiol h... more The synthesis of a series of diacetylenic compounds related to the natural product falcarindiol has been carried out. Unsymmetrical diacetylenes were prepared by a modification of the Cadiot-Chodkiewicz coupling reaction, while a Glaser coupling was used to prepare symmetrical diacetylenes. These compounds have been tested for in vitro cytotoxic activity against Hep-G2, and H-4-II-E cell lines. Diacetylenes with additional unsaturation at C-1, 2, appended with hydroxyl groups at C-3 and C-8, or with long hydrophobic chains, exhibited IC 50 values in the micromolar range.
Nucleic Acids Research, 1995
The interaction of DNA dependent RNA polymerase of the extreme thermophile bacteria Thermotoga ma... more The interaction of DNA dependent RNA polymerase of the extreme thermophile bacteria Thermotoga maritima with a promoter bearing DNA fragment was investigated in the temperature range from 20 to 850C. We show that the T.maritima RNA polymerase recognizes and utilizes the Escherichia coliT7 Al promoter with an efficiency similar to that of the E.coli polymerase. We have investigated the interaction of both polymerases with the same promoter over a wide range of temperatures using hydroxyl radical footprinting and osmium tetroxide probing. This study revealed that the T.maritima polymerase goes through a series of isomerisation events very similar to the E.coli polymerase, i.e. the closed, intermediate and open complexes, but the transitions themselves occur at radically different temperatures. This indicates that conformational changes in the DNA that accompany initiation of transcription such as promoter melting are determined by the polymerase rather than the DNA sequence.
European Journal of Biochemistry, 1999
The active form of HIV-1 reverse transcriptase (RT) is a p66/p51 heterodimer, in which the p51 su... more The active form of HIV-1 reverse transcriptase (RT) is a p66/p51 heterodimer, in which the p51 subunit is generated by C-terminal proteolytic cleavage of p66. A well-known problem of p66 recombinant expression is partial cleavage of a 15-kDa peptide from the C-terminus by host proteases that can not be completely suppressed. In order to analyse the contribution of specific residues to a particular function in one distinct subunit, an expression and purification system is required that selects for the combination of the two individual subunits with the desired substitutions. We reconstituted the p66/p51 heterodimer from subunits coexpressed in Escherichia coli as an N-terminal fusion protein of glutathione S-transferase (GST) with p51 and a C-terminally His-tagged p66, respectively. The two-plasmid coexpression system ensures convenience for gene manipulation while degradation is reduced to a minimum, as dimerization protects the protein from further proteolysis. The combination of glutathione-agarose, phenyl-superose and Ni/nitrilotriacetate affinity chromatography allows rapid and selective purification of the desired subunit combination. Truncated forms of p51 are efficiently removed. Mobility-shift assay revealed that the preparations are free of p66 homodimer. In a successful test of the novel expression system, mixed reconstituted RTs with p51 selectively mutated in a putative nucleic acid binding motif (the so called helix clamp) show reduced binding of dsDNA in mobility-shift assays. This indicates the p51 subunit has an active role in DNA binding
The Journal of Antibiotics, 1984
Two series of new semisynthetic rifamycin SV derivatives have been prepared. One of them bears a ... more Two series of new semisynthetic rifamycin SV derivatives have been prepared. One of them bears a quaternary ammonium salt at C3 (1-5), and the other a pyridoimidazo system condensed at C3 and C4 (6-11). While compounds 1-5 had poor antibacterial activity in vitro, compounds 6-11 were found to be highly active in vitro but poorly absorbed in vivo. They could thus have potential as agents in the therapy of intestinal infections. The synthesis and the 1H NMR structure determination of these new compounds are reported.
2006 5th IEEE Conference on Sensors, 2006
We report on the innovative electrical detection of biological binding, based on a thin metal oxi... more We report on the innovative electrical detection of biological binding, based on a thin metal oxide (MOX) film as channel for a field effect transistor. The working principle relies on modulation of a MOX space charge region (SCR) instead of an enriched/depleted Si channel like in chem-FETs. The feasibility of the working principle was at first demonstrated by pH measurement in liquid. Afterwards we implemented a reliable protocol for the immobilization of ODNs and for the electrical detection of their hybridization. Work is in progress to scale MOX down to nanosized nanowire.
Biomolecular Engineering, 2007
Carboxylic terminated monolayers have been covalently attached on phosphorous doped crystalline (... more Carboxylic terminated monolayers have been covalently attached on phosphorous doped crystalline (1 0 0) silicon surfaces using a cathodic electro grafting technique. The functionalization concentration and efficiency have been evaluated with different techniques. In particular, topographic images, performed with an atomic force microscope, were used to optimize the protocol in order to obtain a surface whose characteristics of uniformity and reproducibility are ideal for a bio-electronic device. Phase lag images of the functionalized surfaces were also performed, and show non-topographic structures that have been interpreted as areas of different molecule self-orientation. Poly-thymine oligonucleotides have been anchored on such a surface to form a nano-biosensing device capable to react selectively with a specific target molecule, a poly-adenine oligonucleotide. AFM images of high density ($3 Â 10 12 mol/cm 2) single strand and double strand covered samples show toroidal shaped structures formed by the self-assembly of the oligonucleotides on the silicon surface.
Antiviral chemistry & chemotherapy, 1999
A series of chemically oversulphated galactosaminoglycans (SO3H:COOH ratio > or = 2) were test... more A series of chemically oversulphated galactosaminoglycans (SO3H:COOH ratio > or = 2) were tested in vitro as antiviral agents against human immunodeficiency virus type 1 (HIV-1), the aetiological agent of AIDS, and against herpes simplex virus type 1 and human cytomegalovirus, two agents responsible for opportunistic infections in HIV-infected people. The oversulphated derivatives displayed an increase in activity ranging from one to four orders of magnitude against the three viruses, as compared to the natural parent compounds (SO3H:COOH, ratio approx. 1). The antiviral activity of these polyanions appears to be favoured by a high degree of sulphation and a high molecular mass. An oversulphated dermatan, with a SO3H:COOH ratio of 2.86 and molecular mass of 23.2 kDa, was the most potent anti-HIV-1 compound (EC50 0.04 microgram/ml). A second oversulphated dermatan, with a SO3H:COOH ratio of 2.40 and molecular mass of 25 kDa, displayed the highest activity against HSV-1 (EC50 0.01 ...
Chembiochem, Jan 25, 2010
Inflammation, Sep 1, 1997
Http Dx Doi Org 10 1080 15257770008033053, Sep 24, 2006
Journal of Medicinal Chemistry, Jul 10, 1992
International Journal of Pharmaceutics, 1996
Engineering in Translational Medicine, 2013
Journal of Medicinal Chemistry, 1992
European Journal of Medicinal Chemistry, 1989
Bioorganic & Medicinal Chemistry, 2008
Journal of Medicinal Chemistry, 1992
CHEMICAL & PHARMACEUTICAL BULLETIN, 2000
The synthesis of a series of diacetylenic compounds related to the natural product falcarindiol h... more The synthesis of a series of diacetylenic compounds related to the natural product falcarindiol has been carried out. Unsymmetrical diacetylenes were prepared by a modification of the Cadiot-Chodkiewicz coupling reaction, while a Glaser coupling was used to prepare symmetrical diacetylenes. These compounds have been tested for in vitro cytotoxic activity against Hep-G2, and H-4-II-E cell lines. Diacetylenes with additional unsaturation at C-1, 2, appended with hydroxyl groups at C-3 and C-8, or with long hydrophobic chains, exhibited IC 50 values in the micromolar range.
Nucleic Acids Research, 1995
The interaction of DNA dependent RNA polymerase of the extreme thermophile bacteria Thermotoga ma... more The interaction of DNA dependent RNA polymerase of the extreme thermophile bacteria Thermotoga maritima with a promoter bearing DNA fragment was investigated in the temperature range from 20 to 850C. We show that the T.maritima RNA polymerase recognizes and utilizes the Escherichia coliT7 Al promoter with an efficiency similar to that of the E.coli polymerase. We have investigated the interaction of both polymerases with the same promoter over a wide range of temperatures using hydroxyl radical footprinting and osmium tetroxide probing. This study revealed that the T.maritima polymerase goes through a series of isomerisation events very similar to the E.coli polymerase, i.e. the closed, intermediate and open complexes, but the transitions themselves occur at radically different temperatures. This indicates that conformational changes in the DNA that accompany initiation of transcription such as promoter melting are determined by the polymerase rather than the DNA sequence.
European Journal of Biochemistry, 1999
The active form of HIV-1 reverse transcriptase (RT) is a p66/p51 heterodimer, in which the p51 su... more The active form of HIV-1 reverse transcriptase (RT) is a p66/p51 heterodimer, in which the p51 subunit is generated by C-terminal proteolytic cleavage of p66. A well-known problem of p66 recombinant expression is partial cleavage of a 15-kDa peptide from the C-terminus by host proteases that can not be completely suppressed. In order to analyse the contribution of specific residues to a particular function in one distinct subunit, an expression and purification system is required that selects for the combination of the two individual subunits with the desired substitutions. We reconstituted the p66/p51 heterodimer from subunits coexpressed in Escherichia coli as an N-terminal fusion protein of glutathione S-transferase (GST) with p51 and a C-terminally His-tagged p66, respectively. The two-plasmid coexpression system ensures convenience for gene manipulation while degradation is reduced to a minimum, as dimerization protects the protein from further proteolysis. The combination of glutathione-agarose, phenyl-superose and Ni/nitrilotriacetate affinity chromatography allows rapid and selective purification of the desired subunit combination. Truncated forms of p51 are efficiently removed. Mobility-shift assay revealed that the preparations are free of p66 homodimer. In a successful test of the novel expression system, mixed reconstituted RTs with p51 selectively mutated in a putative nucleic acid binding motif (the so called helix clamp) show reduced binding of dsDNA in mobility-shift assays. This indicates the p51 subunit has an active role in DNA binding
The Journal of Antibiotics, 1984
Two series of new semisynthetic rifamycin SV derivatives have been prepared. One of them bears a ... more Two series of new semisynthetic rifamycin SV derivatives have been prepared. One of them bears a quaternary ammonium salt at C3 (1-5), and the other a pyridoimidazo system condensed at C3 and C4 (6-11). While compounds 1-5 had poor antibacterial activity in vitro, compounds 6-11 were found to be highly active in vitro but poorly absorbed in vivo. They could thus have potential as agents in the therapy of intestinal infections. The synthesis and the 1H NMR structure determination of these new compounds are reported.