INVESTIGADORES
ROCCHETTA iara
congresos y reuniones científicas
Título:
The effect of environmental conditions on life expectancy and physiological ageing of the freshwater bivalve Diplodon chilensis (Hyriidae)
Autor/es:
IARA ROCCHETTA
Lugar:
Jena
Reunión:
Congreso; Alexander von Humboldt Annual Network Meeting; 2013
Resumen:
Why and how animals age, why some species reach
hundreds of years whereas others live only days or months, and what role
environmental factors play are the questions that motivate this proposal.
Bivalves are novel organisms for the study of natural ageing. These
invertebrates have groups of species that have a life span of 400y as well as
others spanning only 1y. The age of bivalves from natural populations can be
determined by counting shell growth bands, which are formed at regular time
intervals. This enables to study the effects of abiotic and biotic environment
factors on senescence and fitness in natural populations.
In
this project I proposed to investigate the effect of different environmental parameters
on growth rates, longevity, and the physiological process of ageing on two
populations of the long-lived freshwater bivalve Diplodon chilensis from environments with different limnological
characteristics (river and lake) in Patagonia, Argentina. For that, I am analysing antioxidant
defence enzymes (SOD, CAT, GST), cell turnover (apoptosis via caspases),
cellular maintenance (metabolic enzymes related to respiration activity),
oxidative damage parameters (TBARS and carbonyls), and stress gene expression (using
real-time PCR) in
relation to age in bivalves and environmental conditions (by analysing
physic-chemical parameters in water samples). In addition, I performed a
transcriptome-based approach, using high-throughput sequencing technology
(Illumina), to obtain
ESTs from the most highly expressed genes associated to stress, thus generating
a data bank for further studies on ageing, ecology, physiology, and toxicology.
During my stay in Germany I am
evaluating not only the physiological parameters on environmental changes and
ageing process with an expert group in this subject (Dr. Abele group), but also
the gene expression pattern associated to apoptosis, antioxidant defence and
Heat Shock Proteins (HSPs). A small transcriptome of Diplodon chilensis patagonicus was determined in order to get a
limited number of expressed genetic sequence tags. This is aimed at generating
an array of PCR applicable sequences for genes from this important
limnic key species of the Patagonia, D. chilensis, which will help
me to do more extended stress studies using qPCR in Argentina. Field
experiments for further aging studies using this freshwater bivalve are also
planned, working in continuous collaboration between the Ecology Centre in
Neuquén (CEAN), Patagonia, Argentina and AWI, Dr. Abele group, from Germany.
Preliminary results, showed differences in the
maximum age reached for each population, 30 years for the river and 120 years
for the lake, probably in relation with a faster population growth at early
stages in the river. Not many differences were found between populations on metabolic
parameters, but we could observe some over expression of sequences (37 seq)
related to stress and growth genes in bivalves from the river. Metabolic
depression, in order to save energy and avoid oxidative damage, would seem
occur in bivalves older than 50-60 years for the lake population. This result
shows how the same species, coming from natural populations, can reach
different maximum age (3-fold increased), depending on the different
environmental conditions, like type of sediment, water flow rate, and dissolved
oxygen. More analyse are being conducted in order to have a complete
information in relation with the different abiotic factors found in both
sampling sites.