2. ENVIRONMENTAL ChEMISTRy & TEChNOLOGy 2.1. Lectures

Chem. Listy, 102, s265–s1311 (2008) Environmental Chemistry & Technology
L06 INTEGRATION METALLOMICS,
PROTEOMICS AND TRANSCRIPTOMICS
IN ENVIRONMENTAL ISSuES
JOSE LUIS GóMEZ-ARIZA, MACAREnA GOnZALEZ-
FERnAnDEZ, TAMARA GARCIA-BARRERA, JUAn
LOPEZ-BAREA and CARMEn PUEYO
Universidad de Huelva, Departamento de Química y Ciencia
de los Materiales; Facultad de Ciencias Experimentales;
Campus de El Carmen; 21007-Huelva (Spain),
ariza@uhu.es
Introduction
Metallomics is one of most recent -omics whose importance
is associated to the presence of metals or any other
heteroelement (e.g. elements different of C, H, n, or O) in
biomolecules. These metal-linked molecules play important
roles in the cells and by extension in the biological behaviour
of the organisms.
Some of these elements are essential for life, marked in
green in the Fig. 1, other are non-essential or toxic, marked
in red. This is the case of transition elements, such as Fe in
Cytochrome P450, a superfamily of enzymes that regulate the
metabolism of pollutants, drugs and steroids. As well as Fe in
transferrin, that transport and deliver this element. Cobalt is
the key-element of B12 vitamin and ni in urease (the enzyme
for urea hydrolysis into carbon hydroxide and ammonia).
Other transition elements such as Cu and Zn are responsible
for the activity of the superoxide dismutase, which is involved
in the elimination of superoxide radical.
Fig. 1. Essential (green) and non-essential (red) elements
Together with elements linked to these proteinous
molecules other non-proteinous molecules of high molecular
weigh, such as DnA is characterized by the presence of phosphorus,
or boron in polysaccharides from vegetal cell walls.
Therefore, the chemistry of a cell and by extension of
living tissues and biological fluids can be characterized, not
only by its typical genome and proteome, but also by the
metallome, the distribution of metals and metalloids among
the different biomolecules. The metallome describes, per
analogy with genome and proteome, the entirety of metal and
metalloid species within a cell or tissue type. 1–4 The scope of
metallomics is very broad, focusing on developments of new
analytical techniques and instruments, as well as innovative
applications focused on environmental, food or health issues.
s303
I n s t r u m e n t a l A p p r o a c h e s i n M e t a l -
l o m i c s
Three-dimensional systems should be at least used
in Metallomics: (i) a separation component by gel electrophoresis
or HPLC; (ii) an very sensitive elemental monitoring
system, for metal or non-metal quantification, mainly
ICP-MS; and (iii) a component for the structural characterization
of the molecules, generally based on mass spectrometry.
Therefore, the metal or heteroelement act as tag of the
experiment, heteroatom-tagged proteomics 5 .
I n t e r e s t o f – o m i c s I n t e g r a t i o n
The benefit that Metallomics produces due to the simplification
introduced by the metal tag can be insufficient when
an overall appraisal of complex real problems, such as those
related to environmental, food or health issues is considered.
If we consider a contamination problem, genetic responses
to stress conditions are often regulated at transcriptional
level that can be checked by using the microarray technology
to generate genome-wide transcriptional profiles. The changes
detected by microarrays can be confirmed by RT-PCR
(reverse transcription–PCR). In addition, modifications in
the proteome can also used as markers of pollution as consequence
of protein expression alteration triggered by contamination.
However, these changes in proteins profiles can
not necessarily reflect alterations in gene expression at the
transcript level, but changes from post –transductional modifications.
Therefore, the three -omics are complementary and integration
among them is advisable. However, the difficulties in
integrating data from different -omics technologies in nonlaboratory
strains should not be under-estimated, and the use
of non-inbred strains/species induce a variety of confusing
factors can complicate interpretation. To avoid these problems
in environmental studies we propose the use in parallel
of sequenced model species and proved bioindicators with
gentic sequence homologous to the model. In the present
study we have selected two mouse species: (i) a model organism
used in many studies in the laboratory, whose genetic
sequence can be easily obtaine from database, Mus musculus,
and (ii) an aboriginal species checked as useful sentinel organism
in monitoring programs, Mus spretus 6 .
In the present work a combined application of transcriptomics,
proteomics and metallomics approaches has been
performed in Doñana natural Park, one of the most important
European biological reserves, in which millions of migrating
birds land each year in their way to/from Africa. The couple
M. musculus/M. Spretus was used for this integration.
Experimental
S a m p l i n g A r e a s
Mice were collected in February 2004 at six sites from
Doñana surroundings and the Domingo Rubio Stream, both
at Huelva province (Fig. 2.). Animals were captured with live
traps and taken alive to the nearest laboratory (Huelva University
or Doñana Biological Reserve-CSIC). Their sex and