Different levels of hsp70 and hsc70 mRNA expression in Iberian fish exposed to distinct river conditions

Abstract

Comprehension of the mechanisms by which ectotherms, such as fish, respond to thermal stress is paramount for understanding the threats that environmental changes may pose to wild populations. Heat shock proteins are molecular chaperones with an important role in several stress conditions such as high temperatures. In the Iberian Peninsula, particularly in Portugal, freshwater fish of the genus Squalius are subject to daily and seasonal temperature variations. To examine the extent to which different thermal regimes influence the expression patterns of hsp70 and hsc70 transcripts we exposed two species of Squalius (S. torgalensis and S. carolitertii) to different temperatures (20, 25, 30 and 35 °C). At 35 °C, there was a significant increase in the expression of hsp70 and hsc70 in the southern species, S. torgalensis, while the northern species, S. carolitertii, showed no increase in the expression of these genes; however, some individuals of the latter species died when exposed to 35 °C. These results suggest that S. torgalensis may cope better with harsher temperatures that are characteristic of this species natural environment; S. carolitertii, on the other hand, may be unable to deal with the extreme temperatures faced by the southern species.

Influence of Normal Aging on Brain Autophagy: A Complex Scenario

“…Western blot is often used for examining changes in LC3-I and LC3-II levels ( Tanida et al, 2005 ), but there are some caveats to the use of this procedure: (a) the concentration of LC3-I is higher than LC3-II in the brain, so LC3-II may be difficult to detect by western blot in crude homogenates ( Chu et al, 2009 ; Yang et al, 2011 ); (b) LC3-I is more susceptible than LC3-II to degradation in SDS sample buffer or by exposure to freeze/thaw cycles; and (c) LC3-II levels measured by western blot should be compared to the levels of one or more loading control proteins rather than to LC3-I ( Klionsky et al, 2016 ). Specific markers for CMA are presently limited to lamp2a and HSPA8/hsc70, but only the lysosomal membrane levels of these proteins correlate with CMA activity so their detection by Western blot or RT-PCR ( Zhang et al, 2006 ; Jesus et al, 2013 ) should optimally be performed on lysosome-enriched fractions ( Klionsky et al, 2016 ). Immunodetection of lamp2a should be done with antibodies which are specific for lamp2a ( Patel and Cuervo, 2015 ).…”

Broad-scale sampling of primary freshwater fish populations reveals the role of intrinsic traits, inter-basin connectivity, drainage area and latitude on shaping contemporary patterns of genetic diversity

“…(2) Is the genetic diversity of each population influenced by the area and by the hydrological regime of the river drainages they inhabit? (3) Does latitude influence genetic diversity, given that populations from northern rivers are subjected to lower temperatures and fewer temperature fluctuations, contrasting with those from southern rivers which are exposed to higher temperatures, lower oxygen concentrations and cyclical regimes of floods and droughts ( Magalhães, Schlosser & Collares-Pereira, 2003 ; Henriques, Sousa & Coelho, 2010 ; Füssel et al, 2012 ; Jesus, Inácio & Coelho, 2013 )? (4) Do populations of species with wider distribution ranges show higher overall genetic diversity than those with more geographically confined distributions?…”

Chronic wounds alter the proteome profile in skin mucus of farmed gilthead seabream

“…Both HSP70 and HSC70 may have similar cellular roles and have been previously found in skin mucus [ 20 – 23 ]. HSC70 can be mildly modulated by stressors such as heat [ 54 ], pathogens [ 55 ], and heavy metals [ 56 ]. According to these previous studies, at protein level, the present study demonstrated the under-expression of HSC70 in skin mucus after chronic wounds.…”