4.4 Ribosomal response between heat-tolerant and heat-sensitiveBrachionus species
Ribosome biogenesis is a complex and energy-demanding process requiring
coordination of ribosomal RNA (rRNA) and ribosomal protein production.
Ribosomal proteins have been mentioned several times to participate in
stress response and they have been either induced or suppressed upon
temperature increase (Lim et al., 2016; Podrabsky & Somero, 2004;
Schoville et al., 2012; Truebano et al., 2010). Ribosomal protein
related genes, in heat tolerant B. calyciflorus s.s., were
up-regulated towards the lower imposed temperature here at 20oC, indicating again that 20 oC
likely comprise stressful conditions for this species. In contrast, in
the heat-sensitive B. fernandoi , ribosomal protein related genes
were up-regulated under mild heat stress (23 oC),
suggesting an increased translation capacity or a protection of
ribosomal function through the addition or replacement of ribosomal
proteins (Meistertzheim, Tanguy, Moraga, & Thébault, 2007). However,
further temperature increase up to 26 oC, resulted in
down-regulation of ribosomal related genes. This suppression of protein
biosynthesis may reflect cellular homeostasis or an energy saving
mechanism to cope with thermal stress, as protein metabolism consumes a
large amount of ATP.