Gene expression profiles of cytosolic heat shock proteins Hsp70 and Hsp90 from symbiotic dinoflagellates in response to thermal stress: possible implications for coral bleaching (original) (raw)
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Marine environmental research, 2016
Climate changes have increased the intensity/frequency of extreme thermal events, which represent serious threats to the health of reef-building corals. Since the vulnerability of corals exposed to thermal stresses are related to their ability to regulate Heat shock proteins (Hsps), we have analyzed together the time related expression profiles of the mitochondrial Hsp60 and the associated changes in tissue pigmentation in Seriatopora caliendrum subjected to 48 h of heat and cold treatments characterized by moderate (±2 °C) and severe (±6 °C) shocks. For the first time, an Hsp60 response was observed in a scleractinian coral exposed to cold stresses. Furthermore, the Hsp60 modulations and the changes in the tissue coloration were found to be specific for each treatment. A strong down-regulation at the end of the treatments was observed following both the severe shocks, but only the severe heat stress led to bleaching in concert with the lowest levels of Hsp60, suggesting that a seve...
Marine environmental research, 2018
Shallow-water corals of the Mediterranean Sea are facing a dramatic increase in water temperature due to climate change, predicted to increase the frequency of bleaching and mass mortality events. However, supposedly not all corals are affected equally, as they show differences in stress susceptibility, as suggested by physiological outputs of corals along temperature gradients and under controlled conditions in terms of reproduction, demography, growth, calcification, and photosynthetic efficiency. In this study, gene expression and induction of a 70-kDa heat shock protein (HSP70) was analyzed in five common shallow-water hard corals in the Mediterranean Sea, namely Astroides calycularis, Balanophyllia europaea, Caryophyllia inornata, Cladocora caespitosa, and Leptopsammia pruvoti. The main aim was to assess the contribution of this evolutionary conserved cytoprotective mechanism to the physiological plasticity of these species that possess different growth modes (solitary vs colon...
Molecular Characterization of the First Heat Shock Protein 70 from a Reef Coral
Biochemical and Biophysical Research Communications, 1999
The branching coral Stylophora pistillata, one of the most abundant hermatypic corals along the coasts of the Red Sea, has been used for many years as a model species for coral biological studies. Here we characterize the first coral heat shock protein 70 gene (SP-HSP70), cloned from S. pistillata, to be used as a tool for studying coral stress response. The cloning was carried out by a combination of PCR methods using heterologous, degenerate HSP70-based primers, followed by plaque-lift screening of a genomic library. The sequenced clone (5212 bp), contains a complete 1953 bp, intronless open reading frame, and 5 and 3 flanking regions of 1,935 and 1,324 bp, respectively. TATA, CAAT, and ATF boxes as well as 11 putative heat shock elements were identified in the SP-HSP70 5 flanking region. A polyadenylation site was identified in the 3 flanking region. SP-HSP70 protein sequence resembles the cytosolic/nuclear HSP70 cluster. RT-PCR studies confirmed SP-HSP70 mRNA expression in corals grown within their normal physiological conditions. Furthermore, SP-HSP70 has been shown to belong to the coral genome and not to its symbiotic algae one, as revealed by SP-HSP70 PCR amplification, using purified algal and coral DNA templates.
The susceptibility of corals to thermal stress by analyzing Hsp60 expression
Marine Environmental Research, 2014
Due to the increasing frequency and severity of the coral bleaching events in the context of global warming, there is an urgent need to improve our understanding of the susceptibility of corals to thermal stresses, particularly at the sub-cellular level. In this context, we examined the modulation of the polyp mitochondrial Hsp60 in three scleractinian coral species (Seriatopora hystrix, Montipora monasteriata and Acropora echinata) under simulated heat shock bleaching at 34 C during a time course of 36 h. All three species displayed a similar initial increase of Hsp60 level which accompanies the increasing paleness of coral tissue. Afterwards, each of them showed a specific pattern of Hsp60 down-regulation which can be indicative of a different threshold of resistance, although it proceeded in synchrony with the complete bleaching of tissues. The finely branched S. hystrix was the species most susceptible to heat stress while the plating M. monasteriata was the most tolerant one, as its Hsp60 down-regulation was less rapid than the branching corals. On the whole, the Hsp60 modulation appears useful for providing information about the susceptibility of the different coral taxa to environmental disturbances.
Journal of Experimental Marine Biology and Ecology, 2000
Previously it was found that the expression of selected heat-shock proteins is upregulated in corals after exposure to elevated temperature. We published that HSPs are suitable markers in sponges to monitor the degree of environmental stress on these animals. In the present study the heat-shock proteins (HSPs) with a molecular weight of 90 kDa have been selected to prove their potential usefulness as biomarkers under controlled laboratory conditions and in the field. The studies have been performed with the octocoral Dendronephthya klunzingeri from which the cDNA coding for HSP90 was cloned first. The expression of the HSP90 gene is upregulated by thermal stress; treatment of the animals for 2 h at 48C below or above the ambient temperature resulted in a . 4.5-fold higher steady-state level of the respective mRNA. Also animals taken from stressed locations in the field showed an increased expression. The amount of HSP90 protein in D. klunzingeri was found to be strongly increased under thermal stress, or exposure to polychlorinated biphenyl (congener 118), but not after treatment with cadmium. Field studies revealed that samples taken from a nonstressed area have a low level of HSP90, but those collected from locations at which the corals are under physical stress (sedimentation through landfilling) show a high expression of HSP90. It is concluded that the chaperone HSP90 might become a suitable biomarker to monitor environmental stress on corals.
Marine Biotechnology, 2014
Abalone (Haliotis) are economically important molluscs for fisheries and aquaculture industries worldwide. Despite this, genomic resources for abalone and molluscs are still limited. Here we present a description and functional annotation of the greenlip abalone (Haliotis laevigata) transcriptome. We present a focused analysis on the heat shock protein 70 (HSP70) family of genes with putative functions affecting temperature stress and immunity. A total of~38 million paired end Illumina reads were obtained, resulting in a Trinity assembly of 222,172 contigs with minimum length of 200 base pairs and maximum length of 33 kilobases. The 20,702 contigs were annotated with gene descriptions by BLAST. We created a program to maximise the number of functionally annotated genes, and over 10,000 contigs were assigned Gene ontologies (GO terms). By using CateGOrizer, immunity related GO terms for stressors such as heat, hypoxia, oxidative stress and wounding received the highest counts.
Heat shock protein 70 response to physical and chemical stress in Chamelea gallina
Journal of Experimental Marine Biology and Ecology, 2011
Intertidal area is characterized by several fluctuations in natural agents and anthropogenic factors (oxygen levels, temperature, salinity, B[a]P presence) that cause a noticeable increase in the expression rate of heat shock protein 70 (HSP70). HSPs acting as molecular chaperones and their induction represent a specific cellular defence mechanism in response to several stress. Chamelea gallina specimens from the North Adriatic coast were exposed to different experimental conditions: varying oxygen levels (48 h of anoxia followed by 24 h of normoxic recovery), temperatures (20, 25, 30°C for 7 days), salinity (28, 34, 40‰ for 7 days) and B[a]P concentrations (0.5 mg/L for 24 h, 7 and 12 days). Following the extraction of the digestive gland and gills, HSP70 levels were identified in the cytosolic fraction by immunoblotting using primary monoclonal antibodies. An increase in the rate of HSP70 expression under anoxic conditions in the digestive gland was observed at high temperatures, at low salinity and in the presence of B[a]P. The protein was overexpressed in the absence of oxygen and after 12 days of B[a]P exposure, while it was underexpressed in hyposaline conditions in the gills. HSP70 induction can be considered an adaptation mechanism associated with changes in environmental parameters, but also with xenobiotic presence. The overexpression of HSP70 is therefore induced by protein damage due to stressogenic factors. HSP recruitment renders them available for the processes of folding and refolding of denatured proteins or for their transport to a degradation system. The evident sensitivity of HSP70 to natural and anthropogenic stressogenic agents was examined in the present research. The results of this research revealed an interesting response of heat shock protein 70 in C. gallina, underlining the sensitivity of this important commercial species to natural and anthropogenic stress agents.