miR-210-5p对南极独角雪冰鱼心脏发育的作用机制研究

microRNA为短链非编码RNA,通过与靶基因3'UTR序列互补在转录后水平发挥作用。已有研究表明,microRNA在心脏发育过程中起着重要的调控作用。南极冰鱼因体内缺乏功能性血红细胞,其心脏出现了补偿性增生。前期的研究提示,独角雪冰鱼心脏中特异表达的microRNAs可能与冰鱼心脏的补偿性增生相关。本研究针对南极冰鱼心脏中高表达的miR-210-5p,运用斑马鱼显微注射、靶基因预测等手段研究了miR-210-5p对心脏发育的作用机制。结果表明:斑马鱼胚胎注射miR-210-5p后,出现心包膜水肿,心脏发育畸形等现象。qRT-PCR分析显示,过表达miR-210-5p的斑马鱼胚胎中,心脏发育相关的标志性基因bmp4、smad1、gata6以及tbx2b的表达水平下调。Western blotting分析发现,bmp/smad通路中的BMP2、BMP4、SMAD1、GATA6以及TBX2B的蛋白表达水平也显著下调。通过对tbx20基因3'UTR的靶基因生物信息学预测,以及对其进行GFP荧光表达分析,发现tbx20基因可能是miR-210-5p的一个靶基因。由此推测,miR-210-5p可能通过抑制tbx20基因的表达,并调控bmp/smad通路以抑制冰鱼心脏发育。     

独角雪冰鱼和伯氏肩孔南极鱼骨骼中的元素分析

为探究缺失血红蛋白的南极独角雪冰鱼Chionodraco hamatus(CH)和具有血红蛋白的伯氏肩孔南极鱼Trematomus bernacchii(TB)骨骼中元素含量的差异,采用电感耦合等离子体质谱法对两种南极鱼的脊椎骨与头盖骨中Na、Mg、Al、K、Ca、56Fe、Zn等常量元素,以及V、Cr、Mn、As、Se、206Pb等微量元素含量进行了测定与分析。结果表明:两种南极鱼脊椎骨中Al、K、56Fe、Mn、Se含量有显著性差异(P0.05),头盖骨中Mg、K、Ca、56Fe、V、Mn等元素含量有显著性差异(P0.05),推测此差异可能与南极冰鱼缺失功能性血红细胞有关;将两种南极鱼脊椎骨骨骼中的元素含量与7种非南极海水鱼和3种淡水鱼相比,发现两种南极鱼骨骼中K、Na、Mg、56Fe、Zn、Ca等常量元素含量较少,且Mn、V、Cr、206Pb等微量元素含量明显低于非南极鱼,这可能与南极海域存在较低污染相关。本研究中首次测定了两种南极鱼骨骼中的元素含量,为后续拟通过体内组织元素分析探索南极鱼类的生理差异提供了科学依据。     

虾籽酱发酵工艺条件的优化及其挥发性风味成分研究

为改善虾籽酱传统加工周期长、高盐和品质不均一的不足,通过正交试验优化虾籽酱的发酵工艺条件,制备出一种发酵时间短、盐分低的虾籽酱,并采用顶空固相微萃取结合气相色谱—质谱联用技术对挥发性风味成分进行分离鉴定。结果表明,虾籽酱的二次发酵工艺条件为:温度20℃,加盐量11%,先发酵7 d,之后添加5%黄酒和7%糖,再发酵21d;此条件下制得的虾籽酱感官得分为83.5分,氨基酸态氮含量为0.56 g·100 m L~(-1)。虾籽酱中检出25种挥发性成分,主要为烃类、醇类、醛类、酮类、脂类;与原料虾籽相比,丁香醛和酯类化合物相对含量明显增加,(E,E)-3,5-辛二烯-2-酮和1-戊烯-3-醇相对含量明显减少,它们相互作用,可共同构成虾籽酱的特征风味。本研究为低盐虾籽酱的工业生产和风味研究提供了理论依据。     

A production season of turbot larvae Scophthalmus maximus (Linnaeus, 1758) reared on copepods in a Danish (56°N) semi‐intensive outdoor system

Turbot were reared from yolk sack larvae to juvenile in an outdoor semi‐intensive system. Three production cycles were monitored from May to September. A pelagic food chain was established with phytoplankton, copepods and turbot larvae. Abiotic and biotic parameters of lower trophic levels together with turbot larval survival, development, prey electivity and growth were monitored. A decreasing larval survival from 18.4% in May to 13.6% in July and just 7.0% in September was observed. The overall phytoplankton and copepod abundance decreased during the productive season. The turbot larval growth showed significant differences between larvae below (isometric) and above (allometric) 7 mm. Larval fish gut content showed no differences with available prey between production cycles. Therefore, it appears that the available prey concentration is governing their growth in this outdoor system. First‐feeding turbot larvae exhibited active selection for nauplii whereas developed larvae switched to copepodites and adult copepods. Although developing turbot larva exhibited active selection towards copepod size classes, there was no evidence of selective feeding on either of the two dominant copepod species. The turbot larvae's prey ingestion was modelled together with the standing stock of copepod biomass. The model results indicated that the estimated need for daily ingestion exceeded the standing stock of copepods. Hence, the initially established food web was unable to sustain the added turbot larvae with starvation as a consequence. We therefore suggest several solutions to circumvent starvation in the semi‐intensive system.     

独角雪冰鱼和伯氏肩孔南极鱼TRPV1基因的克隆及低温适应功能检测

为从细胞水平上研究独角雪冰鱼Chionodraco hamatus和伯氏肩孔南极鱼Trematomus bernacchii的低温适应能力,采用RT-PCR方法,获得独角雪冰鱼和伯氏肩孔南极鱼的瞬时受体电位阳离子通道蛋白(transient receptor potential channels V1,TRPV1)基因序列,其开放阅读框全长均为2310 bp;生物信息学分析表明,两种南极鱼TRPV1基因均编码769氨基酸残基,预测其蛋白相对分子质量分别为88 210和88 160,理论等电点分别为7.63和8.26;两种南极鱼TRPV1蛋白均无信号肽;亚细胞定位显示,TRPV1蛋白主要在细胞膜和内质网中发挥生物学功能;理化性质分析表明,两种南极鱼的TRPV1为不溶性跨膜蛋白,分别有34、35个磷酸化位点和6、5个糖基化位点,二者均含有6个跨膜结构域、5个锚蛋白结构域,二级结构以随机卷曲为主;同源性分析显示,独角雪冰鱼TRPV1氨基酸序列与伯氏肩孔南极鱼的一致性最高,为93.4%,与其他物种的一致性为44.3%~69.8%;低温适应试验结果显示,两种南极鱼的TRPV1基因不能被温度所激活。研究表明,独角雪冰鱼和伯氏肩孔南极鱼TRPV1基因可能与低温适应无关。     

The effect of temperature and duration of incubation on the hatching of diapause eggs of Centropages hamatus (Lilljeborg) (Copepoda, Calanoida)

Diapause eggs of Centropages hamatus were used to investigate the effect of temperature and duration of incubation on egg hatching. Eggs were incubated for 10, 12, 14, 16, 20, 24, 28, 32, 36 and 40 h at 15°C and 14L–10D. After incubation for the designated period, eggs were transferred to 25°C and monitored periodically to determine egg hatching. Control eggs were incubated solely at 15°C and monitored for egg hatching. The greatest daily hatching success of eggs occurred within 1 or 2 days after transfer from 15°C to 25°C, while the controls required 3–4 days. The cumulative hatching success of eggs was significantly lower than the control, with the exception of eggs held for at least 36 h at 15°C before transfer to 25°C. These results indicate that overall time to hatching of diapause eggs of C. hamatus can be reduced by transferring the eggs to a higher temperature, for example, 25°C, following a minimum period of time (36 h) at reduced temperature, for example, 15°C. Exposure to 15°C for only 10 h does not appear to be sufficient to result in any subsequent hatching at higher temperature.