Protein analysis and gene expression indicate differential vulnerability of Iberian fish species under a climate change scenario

Current knowledge on the biological responses of freshwater fish under projected scenarios of climate change remains limited. Here, we examine differences in the protein configuration of two endemic Iberian freshwater fish species, Squalius carolitertii and the critically endangered S. torgalensis that inhabit in the Atlantic-type northern and in the Mediterranean-type southwestern regions, respectively. We performed protein structure modeling of fourteen genes linked to protein folding, energy metabolism, circadian rhythms and immune responses. Structural differences in proteins between the two species were found for HSC70, FKBP52, HIF1α and GPB1. For S. torgalensis, besides structural differences, we found higher thermostability for two proteins (HSP90 and GBP1), which can be advantageous in a warmer environment. Additionally, we investigated how these species might respond to projected scenarios of 3° climate change warming, acidification (ΔpH = -0.4), and their combined effects. Significant changes in gene expression were observed in response to all treatments, particularly under the combined warming and acidification. While S. carolitertii presented changes in gene expression for multiple proteins related to folding (hsp90aa1, hsc70, fkbp4 and stip1), only one such gene was altered in S. torgalensis (stip1). However, S. torgalensis showed a greater capacity for energy production under both the acidification and combined scenarios by increasing cs gene expression and maintaining ldha gene expression in muscle. Overall, these findings suggest that S. torgalensis is better prepared to cope with projected climate change. Worryingly, under the simulated scenarios, disturbances to circadian rhythm and immune system genes (cry1aa, per1a and gbp1) raise concerns for the persistence of both species, highlighting the need to consider multi-stressor effects when evaluating climate change impacts upon fish. This work also highlights that assessments of the potential of endangered freshwater species to cope with environmental change are crucial to help decision-makers adopt future conservation strategies.info:eu-repo/semantics/publishedVersio

Finishing the euchromatic sequence of the human genome

The sequence of the human genome encodes the genetic instructions for human physiology, as well as rich information about human evolution. In 2001, the International Human Genome Sequencing Consortium reported a draft sequence of the euchromatic portion of the human genome. Since then, the international collaboration has worked to convert this draft into a genome sequence with high accuracy and nearly complete coverage. Here, we report the result of this finishing process. The current genome sequence (Build 35) contains 2.85 billion nucleotides interrupted by only 341 gaps. It covers ∼99% of the euchromatic genome and is accurate to an error rate of ∼1 event per 100,000 bases. Many of the remaining euchromatic gaps are associated with segmental duplications and will require focused work with new methods. The near-complete sequence, the first for a vertebrate, greatly improves the precision of biological analyses of the human genome including studies of gene number, birth and death. Notably, the human enome seems to encode only 20,000-25,000 protein-coding genes. The genome sequence reported here should serve as a firm foundation for biomedical research in the decades ahead

Nitric Oxide Responses of Air-Breathing and Water-Breathing Fish.

Nitric oxide (NO), exogenously administered or endogenously produced by NO synthase (NOS), is an important regulator of lung ventilation and perfusion in mammals. This study attempts to investigate the evolutionary history of this system in fish and its possible relationship to air breathing. The gas bladder of Hoplerythrinus unitaeniatus (air-breathing teleost) and Oncorhynchus mykiss (non-air-breathing teleost) and the lung of Lepidosiren paradoxa (air-breathing dipnoan) all exhibited elevated guanosine 3',5'-cyclic monophosphate (cGMP) levels in response to 1 microM sodium nitroprusside. Only the H. unitaeniatus gas bladder responded to 10 microM acetylcholine chloride (ACh) with increased cGMP levels. The ACh response was inhibited by N omega-nitro-L-arginine methyl ester, which inhibits NOS. These data suggest that although tissues from each species may respond to exogenous NO, only the gas bladder of H. unitaeniatus appears to synthesize NO through NOS. This is the first report of constitutive NOS outside of the central nervous system in a teleost. These results also imply that NOS did not necessarily coevolve with air breathing in fish. </jats:p