Proteomics: Applications and Advances 18.5 Environment 483
Part C | 18.5
Most marine invertebrates have a biphasic life cycle,
where the fitness of the pelagic larval stage is responsible for the success of the benthic adult stage in that
they must locate a suitable substrate for attachment and
subsequent metamorphosis to the adult form, while simultaneously dealing with the cumulative effects of
environmental stress imposed by climate change. Consequently, larvae that undergo settlement and metamorphosis may exhibit a more detectable proteome response to environmental stressors compared to the adult
form due to their rapid development, greater susceptibility, and the complex developmental reprogramming
that occurs in the proteome during the larval–juvenile
transition [18.57]. Since barnacles are model organisms used in studies of larval development in intertidal
benthic invertebrates, Wong et al. [18.54] investigated
the effect of OA on protein expression in metamorphosing larvae of the economically and ecologically
important barnacle Balanus amphitrite, which were cultured from nauplius to the cyprid stage under current
and projected CO 2 concentrations for the year 2100.
Two-dimensional polyacrylamide gel electrophoresis
revealed proteins that were differentially up or downregulated in response to OA which could be placed in
three major functional groups: energy-metabolism, respiration, and molecular chaperones, possibly reflecting
the strategy employed by the barnacle larvae to tolerate
OA stress.
In a study investigating the effect of OA on C. virginica, the proteomes of mantle tissue samples obtained
from animals exposed to normal (39 Pa pCO 2 ) and
hypercapnic (357 Pa pCO 2 ) conditions were analyzed
for changes induced by elevated CO 2 [18.58]. Proteomic analysis revealed 54 of the 456 proteins (12%)
detected by 2D-PAGE were differentially expressed in
response to hypercapnic conditions; 17 of the proteins
responding to elevated CO 2 were identified and found
to either be associated with the cytoskeleton or the
oxidative stress response. Tomanek et al. [18.58] suggest that the mantel cytoskeleton is a major target of
oxidative stress caused by elevated CO 2 levels which
increase reactive oxygen species (ROS) either indirectly
by lowering the pH of the organism and/or directly by
interactions between CO 2 and other ROS to form more
free radicals.
One consequence of climate change will be altered
distribution patterns of fish and shellfish as a function of increased water temperatures [18.18, 55]. The
Mediterranean blue mussel Mytilus galloprovincialis
is an invasive species along the southern Californian
coast, which has displaced the more heat-sensitive native species Mytilus trossulus [18.59]. Tomanek and
Zuzow [18.59] investigated changes in the proteome
of gill tissue sampled from the two congeners in response to acute heat stress (exposure to 24, 28, and
32
ı C for 1 h, followed by a 24 h recovery at 13
ı C)
in order to detect responses common to both species
as well as differences that account for the greater
heat tolerance of the invasive mussel. The study found
that the expression of proteins involved in molecular
chaperoning, proteolysis, energy metabolism, oxidative damage, cytoskeleton, and deacetylation reflected
a common heat stress response in both mussels, but also
showed a lower sensitivity to high-temperature damage
in the warm-adapted Mediterranean mussel, which may
explain its increased range in warmer waters. For example, increased expression of a number of molecular
chaperones occurred at a lower temperature in the coldadapted Mytilus trossulus, which also seemed to be incapable of responding to heat-induced oxidative stress
beyond 28
ı C when nicotinamide adenine dinucleotide
phosphate (NADPH)-producing pathways were found
to be down-regulated in order to decrease the production of ROS via the electron transport chain [18.59].
The Tomanek and Zuzow study [18.59] was the
first comparative investigation which identified systems-level differences in the proteome’s response to
acute thermal stress in a pair of congeners whose biogeographic ranges are in flux. In a follow-up study that
investigated temperature acclimation (7, 13, and 19
ı C
for 4 weeks) in the two mussel species, warm acclimation was found to affect proteins that comprise the cytoskeleton and function in energy metabolism, which is
consistent with increased filtration and respiration rates
associated with increased culinary activity [18.60]. Increased levels of molecular chaperones were detected
in Mytilus trossulus at 19
ı C that were not evident in
Mytilus galloprovincialis, reflecting differences in the
long-term upper thermal limits of the congeners and
suggesting that 19
ı C is close to the chronic thermal
limit of Mytilus trossulus. Although their data indicate
that Mytilus trossulus may have a competitive advantage at colder temperatures, Fields et al. [18.60] suggest
that their study shows why Mytilus galloprovincialis
displaced Mytilus trossulus in southern California and
indicates that climate change could increase this competitive advantage.
18.5.2 Pollution
Coastal and near-shore regions receive a steady influx of anthropogenic pollutants, which accumulate in
Part C | 18.5
Most marine invertebrates have a biphasic life cycle,
where the fitness of the pelagic larval stage is responsible for the success of the benthic adult stage in that
they must locate a suitable substrate for attachment and
subsequent metamorphosis to the adult form, while simultaneously dealing with the cumulative effects of
environmental stress imposed by climate change. Consequently, larvae that undergo settlement and metamorphosis may exhibit a more detectable proteome response to environmental stressors compared to the adult
form due to their rapid development, greater susceptibility, and the complex developmental reprogramming
that occurs in the proteome during the larval–juvenile
transition [18.57]. Since barnacles are model organisms used in studies of larval development in intertidal
benthic invertebrates, Wong et al. [18.54] investigated
the effect of OA on protein expression in metamorphosing larvae of the economically and ecologically
important barnacle Balanus amphitrite, which were cultured from nauplius to the cyprid stage under current
and projected CO 2 concentrations for the year 2100.
Two-dimensional polyacrylamide gel electrophoresis
revealed proteins that were differentially up or downregulated in response to OA which could be placed in
three major functional groups: energy-metabolism, respiration, and molecular chaperones, possibly reflecting
the strategy employed by the barnacle larvae to tolerate
OA stress.
In a study investigating the effect of OA on C. virginica, the proteomes of mantle tissue samples obtained
from animals exposed to normal (39 Pa pCO 2 ) and
hypercapnic (357 Pa pCO 2 ) conditions were analyzed
for changes induced by elevated CO 2 [18.58]. Proteomic analysis revealed 54 of the 456 proteins (12%)
detected by 2D-PAGE were differentially expressed in
response to hypercapnic conditions; 17 of the proteins
responding to elevated CO 2 were identified and found
to either be associated with the cytoskeleton or the
oxidative stress response. Tomanek et al. [18.58] suggest that the mantel cytoskeleton is a major target of
oxidative stress caused by elevated CO 2 levels which
increase reactive oxygen species (ROS) either indirectly
by lowering the pH of the organism and/or directly by
interactions between CO 2 and other ROS to form more
free radicals.
One consequence of climate change will be altered
distribution patterns of fish and shellfish as a function of increased water temperatures [18.18, 55]. The
Mediterranean blue mussel Mytilus galloprovincialis
is an invasive species along the southern Californian
coast, which has displaced the more heat-sensitive native species Mytilus trossulus [18.59]. Tomanek and
Zuzow [18.59] investigated changes in the proteome
of gill tissue sampled from the two congeners in response to acute heat stress (exposure to 24, 28, and
32
ı C for 1 h, followed by a 24 h recovery at 13
ı C)
in order to detect responses common to both species
as well as differences that account for the greater
heat tolerance of the invasive mussel. The study found
that the expression of proteins involved in molecular
chaperoning, proteolysis, energy metabolism, oxidative damage, cytoskeleton, and deacetylation reflected
a common heat stress response in both mussels, but also
showed a lower sensitivity to high-temperature damage
in the warm-adapted Mediterranean mussel, which may
explain its increased range in warmer waters. For example, increased expression of a number of molecular
chaperones occurred at a lower temperature in the coldadapted Mytilus trossulus, which also seemed to be incapable of responding to heat-induced oxidative stress
beyond 28
ı C when nicotinamide adenine dinucleotide
phosphate (NADPH)-producing pathways were found
to be down-regulated in order to decrease the production of ROS via the electron transport chain [18.59].
The Tomanek and Zuzow study [18.59] was the
first comparative investigation which identified systems-level differences in the proteome’s response to
acute thermal stress in a pair of congeners whose biogeographic ranges are in flux. In a follow-up study that
investigated temperature acclimation (7, 13, and 19
ı C
for 4 weeks) in the two mussel species, warm acclimation was found to affect proteins that comprise the cytoskeleton and function in energy metabolism, which is
consistent with increased filtration and respiration rates
associated with increased culinary activity [18.60]. Increased levels of molecular chaperones were detected
in Mytilus trossulus at 19
ı C that were not evident in
Mytilus galloprovincialis, reflecting differences in the
long-term upper thermal limits of the congeners and
suggesting that 19
ı C is close to the chronic thermal
limit of Mytilus trossulus. Although their data indicate
that Mytilus trossulus may have a competitive advantage at colder temperatures, Fields et al. [18.60] suggest
that their study shows why Mytilus galloprovincialis
displaced Mytilus trossulus in southern California and
indicates that climate change could increase this competitive advantage.
18.5.2 Pollution
Coastal and near-shore regions receive a steady influx of anthropogenic pollutants, which accumulate in