Research lines: This specific research line aims to clone and
characterize, genetically and physiologically, the carrier involved
in the a-specific mechanism though which the toxic oxyanion
tellurite is taken up by facultative photosynthetic bacteria; 2.
This second research line aims to determine the toxicity levels of
selenite under various physiological growth conditions along with
the setting up of a rapid and innovative methodology to determine
the cytosolic uptake of this oxyanion in order to understand the
interaction between selenite and the microrganism. 3. The aim of
this project is to develop a method to determine metal(lloid)s and
antibiotics susceptibility in bacterial biofilms and planktonic
cells; 4. This lines involves a series of procedures to study the
co-metabolic degradation under aerobic conditions of alyphatic
chlorinated hydrocarbons (vinyl cloride, chloroform, ethylene
chloride, chloethane) in bacteria growing on buthane and propane.
1. The phototrophic bacterium
Rhodobacter capsulatus is particularly resistant to the
toxic oxyanion tellurite. The cytotoxic action of this metalloid is
due to the pro-oxidant activity of this metalloid. Preliminary data
indicate that tellurite get into cells by means of an
uncharacterized acetate carrier. This project aims to clone and
characterized, both genetically and physiologically, this carrier.
Cloning will be performed on the basis of a bioinformatics approach
using the data presently available in silico or, alternatively, by
means of orthodox techniques such as mutagenesis or mutants
screening. The carrier functional analysis will be based on
tellurite resistance and kinetic parameters along with carrier
expression level as a function of growth conditions.
2. Phototrophic bacteria are
particularly resistant to toxic oxyanions which are included into
group VI A of the periodic table. A few years ago, our research
group started a study on the bacterial response against the toxic
effects of tellurite in Rhodobacter capsulatus. Along with tellurite,
oxyanions such as selenite and selenate are toxic to bacteria and
eukaryotes. Selenium, unlike tellurium, is a fundamental
micro-elements in metabolisms of living organisms. Further, the
oxyanion selenite have an impact on the environment which is much
higher than tellurite. Aim of this project is to determine the
level of toxicity of selenite under various physiological growth
conditions along with setting up a rapid and innovative method to
measure the cytosolic uptake of selenite. These data will be
necessary to understand the interaction between selenite and
bacterial cells.
3. Biofilms are microbial
communities adherent to a solid surface which is included into a
polymeric exocellular matrix. In spite of the fact that biofilms
represent the predominant bacterial form in nature, studies devoted
to understand the effects of metals, metalloids and other toxic
compounds on biofilms are lacking. This research line will be
focused on the development of a methodology to determine bacterial
susceptibility against metals, metalloids and antibiotics in both
biofilms and planktonic cells. Furthermore, several other aspects
will be examined such as: a) RNA-messenger transcription levels; b)
protein synthesis; c) phenotypic features of biofilms made by
Pseudomononas pseudoalcaligenes KF707 in the presence or
absence of meta(lloid)s or antibiotics.
4. This research line, which will
be undertaken in collaboration with DICMA-UniBo, involves a study
on the co-metabolic degradation of chlorinated aliphatic
hydrocarbons (vinyl chloride, chloroform, chloroethylene,
chloroethane) by bacteria growing on propane and butane. This
research will be directed toward the molecular analysis of
bacterial communities by T-RFLP analysis and 16S-DNA sequencing;
further, bacterial species belonging to Rhodococcus genus
and isolated from bacterial consortia degrading propane and butane
will also be analyzed as far as concern their content in
monooxygenases. In addition to isolation and sequencing of the
genes coding for the monooxygense subunits, their expression as a
function of various growth substrates and metabolic pathways will
be examined.
