HSP60 expression profile under different extreme temperature stress in albino northern snakehead, Channa argus

An updated review of cold shock and cold stress in fish

Temperature is critical in regulating virtually all biological functions in fish. Low temperature stress (cold shock/stress) is an often-overlooked challenge that many fish face as a result of both natural events and anthropogenic activities. In this study, we present an updated review of the cold shock literature based on a comprehensive literature search, following an initial review on the subject by M.R. Donaldson and colleagues, published in a 2008 volume of this journal. We focus on how knowledge on cold shock and fish has evolved over the past decade, describing advances in the understanding of the generalized stress response in fish under cold stress, what metrics may be used to quantify cold stress and what knowledge gaps remain to be addressed in future research. We also describe the relevance of cold shock as it pertains to environmental managers, policymakers and industry professionals, including practical applications of cold shock. Although substantial progress has been made in addressing some of the knowledge gaps identified a decade ago, other topics (e.g., population-level effects and interactions between primary, secondary and tertiary stress responses) have received little or no attention despite their significance to fish biology and thermal stress. Approaches using combinations of primary, secondary and tertiary stress responses are crucial as a research priority to better understand the mechanisms underlying cold shock responses, from short-term physiological changes to individual- and population-level effects, thereby providing researchers with better means of quantifying cold shock in laboratory and field settings.

Molecular cloning and characterization of HSP60 gene in domestic pigeons (Columba livia) and differential expression patterns under temperature stress

Heat shock protein 60 (HSP60) is a well-recognized multifunctional protein, playing a substantial role in protecting organisms from environmental stress. The domestic pigeon (Columba livia) is a promising model organism, with important economic and ecological value, and its health is susceptible to temperature stress. To explore the molecular characteristics, tissue expression profile, and response to temperature stress for HSP60 of Columba livia (ClHSP60), we firstly cloned and characterized the complete cDNA sequence and investigated its expression profile under optimal conditions and acute temperature stress. The cDNA of ClHSP60 contained 2257 nucleotides, consisting of 12 exons with length ranging from 65 to 590 bp. The open reading frame (ORF) encoded 573 amino acids with calculated molecular weight of 60.97 kDa that contained a number of structurally prominent domains or motifs. Under optimal temperature conditions, levels of ClHSP60 expression differed between all the tested tissues (the highest was noted in liver and the lowest in pectoralis major muscle). Under acute temperature stress, five patterns of change were detected in the tested tissues, suggesting that different tissues in domestic pigeons differentially responded to various temperature stress conditions. Upregulation of ClHSP60 expression was highest in the lung and pectoralis major muscle, reflecting the crucial role of these two tissues in temperature regulation. However, the crop, cerebrum, and heart showed little change or decreased ClHSP60 expression. The results indicate that ClHSP60 may be sensitive to and play pivotal roles in responding to acute temperature stress.

Physiological and molecular responses to thermal stress in red cusk-eel (Genypterus chilensis) juveniles reveals atrophy and oxidative damage in skeletal muscle

The red cusk-eel (Genypterus chilensis) is a native species with strong potential to support Chilean aquaculture diversification. Environmental stressors, such as temperature, may generate important effects in fish physiology with negative impact. However, no information exists on the effects of thermal stress in Genypterus species or how this stressor affects the skeletal muscle. The present study evaluated for the first time the effect of high temperature stress in red cusk-eel juveniles to determine changes in plasmatic markers of stress (cortisol, glucose and lactate dehydrogenase (LDH)), the transcriptional effect in skeletal muscle genes related to (i) heat shock protein response (hsp60 and hsp70), (ii) muscle atrophy and growth (foxo1, foxo3, fbxo32, murf-1, myod1 and ddit4), and (iii) oxidative stress (cat, sod1 and gpx1), and evaluate the DNA damage (AP sites) and peroxidative damage (lipid peroxidation (HNE proteins)) in this tissue. Thermal stress generates a significant increase in plasmatic levels of cortisol, glucose and LDH activity and induced heat shock protein transcripts in muscle. We also observed an upregulation of atrophy-related genes (foxo1, foxo3 and fbxo32) and a significant modulation of growth-related genes (myod1 and ddit4). Thermal stress induced oxidative stress in skeletal muscle, as represented by the upregulation of antioxidant genes (cat and sod1) and a significant increase in DNA damage and lipid peroxidation. The present study provides the first physiological and molecular information of the effects of thermal stress on skeletal muscle in a Genypterus species, which should be considered in a climate change scenario.

Expression of HSP70 family mRNAs in albino northern snakehead, Channa argus: Response to extreme temperature stress and bacterial infection

The wild albino northern snakehead, Channa argus, has only been found in Jialing Rivers System of China so far. It is easy to be affected by the environmental factors such as temperature changes and bacterial infection, thus causing a huge economic loss. Therefore, this study cloned a 2,213 bp cDNA that encodes a protein of heat shock protein 70 (CaHSP70), which has an open reading frame (ORF) that encodes 639 amino acids and the corresponding polypeptides of 70.50 kDa. And the oretical isoelectric point (pI) of CaHSP70 is 5.79. Additionally, we also cloned a cDNA for heat shock cognate protein 70 (CaHSC70) with a total length of 2,300 bp. And the ORF of CaHSC70 encodes 648 amino acids and 71.18 kDa peptides. The pI of CaHSC70 is 5.22. Moreover, the cDNA length of stress-70 protein mitochondrial (CaHSPA9) is 2,944 bp with an ORF that encodes 679 amino acids, polypeptides of 73.74 kDa, and a pI of 6.68. The quantitative real-time PCR (qRT-PCR) analysis showed that the mRNA expression levels of CaHSP70, CaHSC70, and CaHSPA9 genes were tissue-specific in the control groups. After the heat shock at 37 °C, the mRNA expression levels of CaHSP70 were extremely significantly upregulated in the kidney, liver, spleen, and brain tissues, while fewer mRNA expression levels of CaHSC70 and CaHSPA9 showed a relatively induction in these tissues. In contrast, after the cold shock at 8.5 °C, fewer mRNA expression levels of CaHSP70, CaHSC70, and CaHSPA9 showed the changes of expression in all the tissues, compared to heat shock. In addition, CaHSP70, CaHSC70, and CaHSPA9 mRNA expression levels showed an overall trend of first upregulating and then falling after Edwardsiella tarda (strain No. DL1,476) challenge. In conclusion, this study demonstrated that temperature had a great effect on the mRNA expression levels of CaHSP70, CaHSC70, and CaHSPA9, and the mRNA expression levels of these three genes were also sensitive to pathogen infection, especially CaHSP70 in the albino C. argus.

Channa argus BMH from Baima Hu Lake: sequencing and phylogenetic analysis of the mitochondrial genome

Northern snakehead, Channa argus, is a commercially important food fish species in China. In the present study, the complete mitochondrial genome of C.argus from the Baima Hu Lake was characterized. It is 16,558 bp in length, consist of 22 tRNA genes, 13 PCD genes, 2 rRNA genes, and 1 D-loop region. The overall base composition of the C. argus mitogenome is 27.26% A, 24.21% T, 31.58% C and 16.95% G, exhibits a similar AT bias (51.47%) feature to other vertebrate mitogenomes. The phylogenetic analysis showed that C. argus clustered in genus Channa. The present resultes provide useful information to population genetics and conservation biology studies of Channa fishes.

Role of Myeloperoxidase of northern snakehead (Channa argus) in Aeromonas veronii infection

Myeloperoxidase (MPO) is a ferrous lysosomal protein with many immune functions that belongs to the heme peroxidase enzyme. In this study, the functions of MPO in the northern snakehead (Channa argus) were investigated by cloning an MPO cDNA sequence with a full length of 3181 bp. Homology analysis showed that northern snakehead MPO gene had the highest (81%) homology with mandarin fish (Siniperca chuatsi). In healthy northern snakehead, the MPO gene was expressed in the head-kidney, kidney, heart, gill, spleen, liver, and muscles but not midgut. After the northern snakehead was infected with Aeromonas veronii, the MPO gene expression varied in different tissues with low level in spleen, liver, gill and muscle, fluctuated in kidney and head-kidney and showed high level in heart. The result indicated that MPO might play an important role in the antimicrobial immune response of the northern snakehead.