| Sea cucumber (Apostichopus japonicus) is mainly produced in coastal regions ofnorth China, it is an important economic aquaculture species. It has the highestnutritional value and a wide range of medicinal value. Temperature is the importantenvironmental factor in effecting the survival, apostichopus growth and reproductionof sea cucumber, a study about the effect of the temperature on survival andphysiological can evaluate the growth status in low temperature and provide somebasic basis for the safety of sea cucumber aquaculture. In recent years, Diseases arisedfrom low temperature make marine aquaculture in north China suffered great loss, themortality of sea cucumber reaches above80%in some areas, and the survival seacucumbers also appear serious ulcerative skin. At present, the harm caused by coastalwinter ice to against sea cucumber breeding and it need to be solved urgently. Inrecent years, the researches about ecological and physiological mechanisms ontemperature change in sea cucumber are deeper, but mostly focus on the hightemperature and aestivation mechanism, the research of low temperature tolerancemechanisms are relatively few. This study simulated the sea cucumber breedingenvironment in winter, and investigated the expression analysis screened genesrelated to low temperature tolerance. It is believed that this study plays an importantrole in researching for the genetic mechanism of sea cucumber cold tolerance atmolecular level. It will promote a further development of sea cucumber aquacultureand scientific study and reduce the diseases of sea cucumber breeding in lowtemperature.In the present study, the full-length sea cucumber Uridine cytidine kinase-1wascloned by using RACE. It was3189bp in length and contained a1557bp open readingframe (ORF), a1506bp3UTR and a126bp5UTR. The full-length Uridine cytidinekinase-1cDNA had AATAAA special sequences in the3′UTR and polyA regions.The full-length Uridine cytidine kinase-1cDNA encoded518amino acids constitutinga58.2KD protein molecule with an isoelectric point of6.50. In these518amino acids,there are66Strongly Basic(+) Amino Acids (K,R),72Strongly Acidic(-) AminoAcids (D,E),177Hydrophobic Amino Acids (A,I,L,F,W,V),117Polar Amino Acids(N,C,Q,S,T,Y). And its molecular formula is C2590H4120N710O773S21. The resultsprovide a reference for investigating the function of this gene.Ferritin, Transferrin, Lysozyme, Hsp70, gp96, Uridine cytidine kinase-1and Toll like receptor were selected from the subtracted cDNA library of Apostichopusjaponicus under acute cold stress. Expression of these genes was investigated indifferent tissues (coelomocyte, respiratory tree, intestine, longitudinal muscle).Transcriptional expression profiles of these genes were studied in the four tissuesresponding to acute and mild temperature droppings respectively. The results showedthat1)The five cold tolerant related genes were found to be tissue-ubiquitous with thehighest mRNA levels observed in coelomocyte and respiratory tree;2)Undertemperature dropping treatments, the transcriptional regulation of those cold tolerantgenes generally presented three corresponding patterns: A primary suppressionfollowed with an up-regulation at-2℃; Throughout suppressed expression; and foroccasionally cases, a first stimulation followed with a recession;3)The acutetemperature dropping treatment caused much severer gene expression suppressionscompared to those by the mild temperature dropping treatment. In conclusion, the fivecold tolerant related genes mainly distributed in coelomocyte and respiratory tree.They were generally down-regulated by the low temperature stress but an inversedup-regulation was found at an extreme temperature (-2℃) when under temperaturedropping treatments. Results above provide novel information to elucidatemechanisms involved in the cold stress of sea cucumber.In the present study, we investigated how temperature stress affects geneexpressions of sea cucumber Apostichopus japonicas. Major yolk protein (MYP) genewas selected as a candidate indicator from our former pilot screening study oncold-resistant genes. Two isoforms of MYP, saying MYP1and MYP2were bothinvolved, to enhance the reliability of inferences drawn by the current study. Temporalexpression features of the two MYP were surveyed for nine developmentalstages(fertilized egg,blastula, gastrula, early auricularia, auricularia, late auricularia,doliolaria, pentactula, juvenile) via qRT-PCR. Tissue distribution for adult A.japonicas was studied for seven tissues(respiratory tree, coelomocyte, intestine,muscle, body wall, testis, ovary). Expression profiles of the two MYP correspondingto a long-term High/Low temperature treatment and a temporal acute cold shocktreatment were investigated respectively, with intestine as the target tissue. The twoMYP presented similarities for temporal expression and tissue distribution: graduallyenhanced expression since doliolarias stage to juvenile stage; and tissue-ubiquitous(but not in coelomic fluid) expression with greatest abundance in intestine.Interestingly, although the expressions of MYP presented a negative linearrelationship with the constant environmental temperature (six times higher for4℃ compared to20℃), a sharp cold shock treatment significantly suppressed them.Findings in our study contribute to study of molecular regulation mechanism onaestivation and hibernation for A. Japonicas. |
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