Chemical composition of lipopolysaccharides isolated from various endophytic nitrogen-fixing bacteria of the genus Herbaspirillum.

Bacteria from the genus Herbaspirillum are endophytes responsible for nitrogen fixation in gramineous plants of economic importance such as maize, sugarcane, sorghum, rice, and wheat. Some species are known to produce plant growth substances. In contrast, Herbaspirillum rubrisubalbicans strains are known to be mild plant pathogens. The molecular communication between the plant and the microbes might involve lipopolysaccharides present in the outer membrane of these gram-negative bacteria. Phenol-water extraction was used to obtain lipopolysaccharides from 7 strains of Herbaspirillum seropedicae (SmR1, Z67, Z78, ZA95, and M2) and H. rubrisubalbicans (M1 and M4). The electrophoretic profiles and chemical composition of the lipopolysaccharides obtained in the phenol and aqueous extracts were shown herein.

Proton-therapy, present status.

At the moment, proton-therapy is the most advanced radiotherapeutic technique in cancer treatment. The use of the high energy proton beam (from 70 MeV to 200 MeV) lets a Bragg's peak be moved to different depths, so allowing personal radiotherapeutic treatment. In recent years, many proton-therapy centers have grown up throughout the world with very satisfactory clinical results, first of all in eye melanoma treatment. The future expectations are very promising, even if the very high installation and maintenance expenses of a synchrotron (for proton production) hinder the development of such a method.