Cellular and molecular effects of protons: apoptosis induction and potential implications for cancer therapy.

Due to their ballistic precision, apoptosis induction by protons could be a strategy to specifically eliminate neoplastic cells. To characterize the cellular and molecular effects of these hadrons, we performed dose-response and time-course experiments by exposing different cell lines (PC3, Ca301D, MCF7) to increasing doses of protons and examining them with FACS, RT-PCR, and electron spin resonance (ESR). Irradiation with a dose of 10 Gy of a 26,7 Mev proton beam altered cell structures such as membranes, caused DNA double strand breaks, and significantly increased intracellular levels of hydroxyl ions, are active oxygen species (ROS). This modified the transcriptome of irradiated cells, activated the mitochondrial (intrinsic) pathway of apoptosis, and resulted in cycle arrest at the G2/M boundary. The number of necrotic cells within the irradiated cell population did not significantly increase with respect to the controls. The effects of irradiation with 20 Gy were qualitatively as well as quantitatively similar, but exposure to 40 Gy caused massive necrosis. Similar experiments with photons demonstrated that they induce apoptosis in a significantly lower number of cells and in a temporally delayed manner. These data advance our knowledge on the cellular and molecular effects of proton irradiation and could be useful for improving current hadrontherapy protocols

Measurements of the rate of interaction between stored electrons and positrons

The paper describes a series of experiments carried out with the purpose of observing the γ-rays produced in the collision between stored beams of electrons and positrons. The interaction rate has been measured and was found to be in good agreement with the hypothesis that there is a complete overlap between the two beams and that the dimensions of the beams are those calculated from the lifetime effect

Locally Sensitive Backtranslation Based On Multiple Sequence Alignment

Backtranslation is the process of decoding an amino acid sequence into a corresponding nucleic acid. Classical methods are based on the construction of a codon usage table by clustering and detection of the most probable codon used for each amino acid. In this paper we present a new method for backtranslation which is sensitive to the local position of the amino acid in the input sequence. The method makes use of multiple sequence alignment of the set of proteins under analysis. A local codon usage table stores for each amino acid X and for each position of X in the alignment the most used codon. We compared our method with EMBOSS using both ClustalW and AntiClustAl for multiple sequence alignment. Experiments showed that our method outperforms EMBOSS in terms of precision of backtranslation: the matching between the proteins obtained by our method and the original protein templates is clearly superior to that obtained by EMBOSS. This enforces the validity of a locally sensitive approach

"LA RESEZIONE-ANASTOMOSI ESOFAGEA PER VARICI".

RELAZIONE - 1O CONGRESSO NAZIONALE F.I.C.C.T.V. SAN MARCO DI CASTELLABATE (SA), 4-6 GIUGNO 1987

In vitro and in silico cloning of Xenopus laevis SOD2 cDNA and its phylogenetic analysis

By using the methodology of both wet and dry biology (i.e., RT-PCR and cycle sequencing, and biocomputational technology, respectively) and the data obtained through the Genome Projects, we have cloned Xenopus laevis SOD2 (MnSOD) cDNA and determined its nucleotide sequence. These data and the deduced protein primary structure were compared with all the other SOD2 nucleotide and amino acid sequences from eukaryotes and prokaryotes, published in public databases. The analysis was performed by using both Clustal W, a well known and widely used program for sequence analysis, and AntiClustAl, a new algorithm recently created and implemented by our group. Our results demonstrate a very high conservation of the enzyme amino acid sequence during evolution, which proves a close structure-function relationship. This is to be expected for very ancient molecules endowed with critical biological functions, performed through a specific structural organization. The nucleotide sequence conservation is less pronounced: this too was foreseeable, due to neutral mutations and to the species-specific codon usage. The data obtained by using AntiClustAl are comparable with those produced with Clustal W, which validates this algorithm as an important new tool for biocomputational analysis. Finally, it is noteworthy that evolutionary trees, drawn by using all the available data on SOD2 nucleotide sequences and amino acid and either Clustal W or AntiClustAl, are comparable to those obtained through phylogenetic analysis based on fossil records