RESUMO
The genome sequence of the Antarctic Gram-negative marine eubacterium Pseudoalteromonas haloplanktis TAC125 is a potential source of useful data on proteins from a cold-adapted microorganism. Identifying the bases of protein adaptation to higher or lower temperatures is important to understand the relationship between structure/function and life history on the Earth. The P. haloplanktis TAC125 genome contains three genes in distinct positions on chromosome I, named PSHAa0030, PSHAa2217 and PSHAa0458. These genes encode three truncated hemoglobins. The amino-acid identity between the three hemoglobins is less than 25% suggesting that these proteins may have different function(s) in bacterial cellular metabolism. The hemoglobin encoded by the PSHAa0030 gene has been cloned, expressed in Escherichia coli, purified and structurally characterised. This truncated hemoglobin is monomeric; circular dichroism shows high temperature resistance. The optical spectra of oxygenated and CO forms are similar to those of other truncated hemoglobins. Phylogenetic analyses show that two truncated globins encoded by the PSHAa0030 and PSHAa2217 genes belong to group II, and the third one encoded by PSHAa0458 to group I.
Assuntos
Proteínas de Bactérias/genética , Hemeproteínas/genética , Pseudoalteromonas/genética , Sequência de Aminoácidos , Regiões Antárticas , Proteínas de Bactérias/química , Proteínas de Bactérias/metabolismo , Dicroísmo Circular , Eletroforese em Gel de Poliacrilamida , Hemeproteínas/química , Hemeproteínas/metabolismo , Dados de Sequência Molecular , Filogenia , Proteínas Recombinantes/química , Proteínas Recombinantes/isolamento & purificação , Proteínas Recombinantes/metabolismo , Alinhamento de Sequência , Homologia de Sequência de Aminoácidos , Espectrofotometria Ultravioleta , TemperaturaRESUMO
The potential pollution loads, of both organic and eutrophicating type, along the Italian coast were evaluated with reference to census data of 1991. The methodology adopted for the indirect evaluation of loads are those developed by the Water Research Institute of the Italian National Research Council. They take into account the different sources of pollution load, namely population, industry, agriculture and cattle farming. Pollution loads were estimated at coastal provinces level. Annual riverine fluxes of pollutants were also evaluated for the main Italian rivers. Finally, the positive role played by the adoption of monitoring plans forecasted by the national law recently come into force (DL.vo 152/99) for a better evaluation of the pollution loads was stressed.