Post-genomics of Neisseria meningitidis: an update.

Neisseria meningitidis infection still remains a major life-threatening bacterial disease worldwide. The availability of bacterial genomic sequences generated a paradigm shift in microbiological and vaccines sciences, and post-genomics (comparative genomics, functional genomics, proteomics and a combination/evolution of these techniques) played important roles in elucidating bacterial biological complexity and pathogenic traits, at the same time accelerating the development of therapeutic drugs and vaccines. This article summarizes the most recent technological and scientific advances in meningococcal biology and pathogenesis aimed at the development and characterization of vaccines against the pathogenic meningococci.

Postgenomics of Neisseria meningitidis: an update.

Neisseria meningitidis infection represents a major life-threatening bacterial disease worldwide. Genomics has revolutionized every aspect of the field of microbiology. As a consequence of genome sequencing, the postgenomic era commenced 15 years ago. Comparative genomics, functional genomics and proteomics, as well as a combination of these techniques, will play important roles in providing vital information regarding bacterial biological complexity and pathogenic traits, and accelerate the development of therapeutic drugs and vaccines for combating infections. This review summarizes the current knowledge regarding different approaches aimed to shed light on meningococcal biology and pathogenesis, and to accelerate the development and characterization of vaccines against pathogenic meningococci.

Oxidative damage mediated by herbicides on yeast cells.

Agricultural herbicides are among the most commonly used pesticides worldwide, posing serious concerns for both humans, exposed to these chemicals through many routes, and the environment. To clarify the effects of three herbicides as commercial formulations (namely, Pointer, Silglif, and Proper Energy), parameters related to oxidative issues were investigated on an autochthonous wine yeast strain. It was demonstrated that herbicides were able to affect the enzymatic activities of catalase and superoxide dismutase, as well as to induce carbonylation and thiol oxidation as post-translational modifications of proteins. Saccharomyces cerevisiae is an optimal model system to study responses to xenobiotics and oxidative stress. Thus, the results obtained could further the understanding of mechanisms underlying the toxicity of herbicides.

Helicobacter pylori: immunoproteomics related to different pathologies.

Helicobacter pylori is a Gram-negative bacterium that causes ulcer, atrophic gastritis, adenocarcinoma and mucosa-associated lymphoid tissue lymphoma. Moreover, an ongoing controversial role of this bacterium infection has been suggested in the etiopathogenesis of some extradigestive diseases. The humoral response to H. pylori during a natural infection can be used for diagnostic purposes and as a basis for vaccine development. Host-pathogen interactions may be investigated by means of immunoproteomics, which provides global information about relevant specific and nonspecific antigens, and thus might be suitable to identify novel vaccine candidates or serological markers of H. pylori infection as well as of different related diseases. In this review, we describe how several research groups used H. pylori proteomics combined with western blotting analysis, using sera from patients affected with different H. pylori-related pathologies, to investigate potential associations between host immune response and clinical outcomes of H. pylori infection, resulting in the rapid identification of novel, highly immunoreactive antigens.

Comparative analysis of the effects of locally used herbicides and their active ingredients on a wild-type wine Saccharomyces cerevisiae strain.

Herbicides are released to the environment with potential ecotoxicological risks for mammals. Yeast is a good model to elucidate toxicity mechanisms. We investigated how three commercial herbicides (Proper Energy, Pointer, and Silglif) and their active ingredients (respectively, fenoxaprop-P-ethyl, tribenuron methyl, and glyphosate) can affect biological activities of an oenological Saccharomyces cerevisiae strain, which may be resident on grape vineyards of the same geographical areas where herbicides are used. The use of commercial grade herbicides employed in Italy allowed us to reproduce the same conditions applied in crops; at the same time, assaying pure single active compounds made it possible to compare the effects obtained with commercial formulations. Interestingly, we found that while pure active compounds affect cell growth and metabolism at a lower extent, commercial preparations have a significant major negative influence on yeast biology.

Inactivation of Helicobacter pylori cagA gene affects motility.

BACKGROUND: The cytotoxin-associated protein CagA is a Helicobacter pylori immunodominant antigen whose gene resides in the cag pathogenicity island. Our purpose was to determine if the disruption or deletion of cagA gene could have an effect on the expression of other proteins at the proteome level. We analyzed two H. pylori strains, 328 and G27 wild-type, bearing the cag pathogenicity island, and their respective isogenic cagA(-) mutants. METHODS: The proteomes of two H. pylori strains (328 and its isogenic mutant SPM328_DeltacagA) were resolved by two-dimensional electrophoresis and the digitalized images obtained were analysed both quantitatively and qualitatively. Peculiar spots of each strain were identified by mass spectrometry or by Western blotting. RESULTS: The comparison between the proteome expression of an H. pylori cagA(+) strain and an isogenic mutant strain where the cagA gene was disrupted showed that, as well as the lack of expression of CagA, both flagellin A and flagellin B expressions were significantly decreased. The cagA(-) isogenic mutant was nonmotile. G27_DeltacagA, in which CagA was inactivated by gene deletion, was nonmotile as well respecting to motile G27 wild-type strain. Moreover, reintroduction of cagA in G27_DeltacagA restored motility. CONCLUSIONS: Our results suggest that CagA could quantitatively influence flaA and flaB transcription or their subsequent translation and/or correct folding.

Proteomic response to physiological fermentation stresses in a wild-type wine strain of Saccharomyces cerevisiae.

We report a study on the adaptive response of a wild-type wine Saccharomyces cerevisiae strain, isolated from natural spontaneous grape must, to mild and progressive physiological stresses due to fermentation. We observed by two-dimensional electrophoresis how the yeast proteome changes during glucose exhaustion, before the cell enters its complete stationary phase. On the basis of their identification, the proteins representing the S. cerevisiae proteomic response to fermentation stresses were divided into three classes: repressed proteins, induced proteins and autoproteolysed proteins. In an overall view, the proteome adaptation of S. cerevisiae at the time of glucose exhaustion seems to be directed mainly against the effects of ethanol, causing both hyperosmolarity and oxidative responses. Stress-induced autoproteolysis is directed mainly towards specific isoforms of glycolytic enzymes. Through the use of a wild-type S. cerevisiae strain and PMSF, a specific inhibitor of vacuolar proteinase B, we could also distinguish the specific contributions of the vacuole and the proteasome to the autoproteolytic process.