Ping Zhuang

Preliminary studies on molecular mechanism of salinity regulation of Na+, K+-ATPase α-subunit in gills of juvenile Chinese sturgeon(Acipenser sinensis)

In order to explore the molecular regulation mechanism of Na+,K+-ATPase(NKA)α-subunit in gills of juvenile Chinese sturgeon at salinity 10,partial NKA α-subunit gene sequence was cloned,and the abundance of α-subunit mRNA,NKA activity,ion concentration and osmolality were examined at 3,6,12,24,48,72,96 hours post-transfer.Results showed that:in experimental group(fresh water-salinity water,FW-SW),the expression of NKA α-subunit mRNA and NKA activity increased significantly(P0.05)during the adaptation phase(0-12 h),and the concentration of Na+,Cl-and osmolality rose to a maximum level at 12 h post-transfer.In regulatory phase(12-24 h),the amounts of NKA α-subunit mRNA and NKA activity fell to a relatively lower level which was still higher than that of fish in control group(P0.05).The change both in ion concentration and osmolality were in accordance with the change of NKA and mRNA expression.In conclusion,gill Na+,K+-ATPase in Chinese sturgeon plays an important role in osmolality regulation by changing α-subunit mRNA expression.The different α-subunit mRNA expression can lead to the variation of enzyme activity which can further regulate the ion concentration and osmolality.

Analysis of fatty acid composition in different tissues of adult female Tridentiger trigonocephalus collected from the Yangtze Estuary

Research was made in this paper on the moisture,lipid content and fatty acid composition of muscle,liver and ovary of adult female Tridentiger trigonocephalus collected from the Yangtze Estuary at Ⅴ stage of ovary development.The results indicated that:(1) The moisture content in muscle,liver and ovary was reduced successively,and the value was significantly different among these three tissues(P0.05).The total lipid content in these three tissues was(1.32%±0.08%),(7.75%±0.38%),and(26.73%±0.59%),respectively.There was significant difference in total lipid content among these three tissues,and the highest was in ovary,followed by liver,and the lowest was in muscle.(2) The content of SFA in muscle was significant higher than that in liver and ovary.There was significant difference in SFA content among three tissues(P0.05).About the MUFA,C16:1 content of liver is the highest.The C16:1 content in muscle,liver and ovary were(11.90%±0.71%),(15.28%±2.42%) and(9.49%±0.37%) respectively,and there was significant difference among these three tissues(P0.05).The content of PUFA,3PUFA,6PUFA in ovary was significantly higher than that in muscle and liver(P0.05),but showed no significant difference between muscle and liver(P0.05).The total content of EPA and DHA in muscle,liver and ovary were increased successively.The total content of EPA and DHA in these three tissues was(30.17%±1.02%),(30.53%±0.50%) and(34.33%±0.71%),respectively.The content of EPA and DHA in ovary was significantly higher than that in muscle and liver(P0.05),but showed no significant difference between muscle and liver(P0.05).The ratio of EPA to DHA(EPA/DHA) in these three tissues was 1.50,1.75 and 1.59 respectively,and the ratio of total 3 polyunsaturated fatty acids to total 6 polyunsaturated fatty acids(∑ 3PUFA/∑ 6PUFA) in these three tissues was 6.44,8.05 and 7.00,respectively.The ratios of EPA/DHA and ∑ 3PUFA/∑ 6PUFA were highest in liver,followed by ovary,and the lowest was in muscle.

Changes in non-specific immune parameters of mature Chinese mitten crab(Eriocheir sinensis) in response to elevated salinities

Mature Chinese mitten crabs,Eriocheir sinensis,are exposed to brackish water or coastal waters as an obligatory part during adult reproductive migration.In this study,we investigated the changes in serum total protein and oxyhemocyanin contents,alkaline phosphatase(AKP),superoxide dismutase(SOD) and phenoloxidase(PO) activities in both mature male and female E.when in freshwater and after step-wise acclimation to the following salinities: 7,14,21,28,35.Increasing salinities caused a gradual decrease in serum total protein and oxyhemocyanin contents.Serum AKP activity was elevated slightly at 7,thereafter it dropped slowly by the end of experiment.Serum SOD activity showed a slight decrease after increase of salinity until 21,it was activated above 21.Serum PO activity decreased gradually with the increase of salinity in males;however,it maintained a stable level above 21 in females.All tested parameters in serum except for SOD were significantly higher in females than those in males.It is suggested that elevated salinity induced a decrease in serum total protein and oxyhemocyanin contents.Serum immune enzyme activities in mature E.sinensis will be affected when the salinity was near to or above 28,which could exert a negative effect on reproduction.Further studies are needed to understand the biochemical adaptation of mature E.sinensis,during their reproductive migration acclimation to elevated salinities.Sex differences should not be ignored.

Effects of cryopreservation on exterior shape and interior structure of Chinese mitten crab (Eriocheir sinensis) embryos

In order to deeply understand the effects of cryopreservation on the configuration of embryos,we chose the Eriocheir sinensis as the object,and observed the exterior shapes and interior structure of different developmental stages embryos after treatment with cryoprotectants and cryopreservation by means of microscope,slice and electron microscopy.Results showed that:(1) Cleavage embryos swelled clearly after treatment with vitrifying solutions by two-step methods,exterior shape of the embryos had no significant difference compared to the control group by three-step equilibration methods,some yolk overflowed from the inner cells and cells were damaged seriously after cryopreservation.(2) Exterior shape of gastrula stage embryos was similar to the control group after treatment with two-step equilibration methods,surface of gastrula stage embryo treated with cryoprotectants crinkled and shaped reticulation structure by scanning electron microscopy(SEM),white gobbet appeared in cells of embryos and fringe of cell was coarse and protuberant by transmission electron microscopy(TEM).After cryopreservation,color of embryos was pink,cell became opaque,the brim of cell membrane was blurry and shaped floss,segmental yolk was disintegrated into granule,the surface of embryos was sunken and wrinkled.(3) Cell membrane of embryos broke off,ice holes of different size appeared inside embryos,visible vacuoles appeared inside cells by slice observation.Ice holes in cells were very clear and some vacuoles appeared,about 80% mitochondria dissolved,breach of cells was very obvious by TEM.Exterior shape of the original zoea stage embryos had no difference compared to that of the control group after treatment with cryoprotectants by microscope and SEM.After cryopreservation,above 95% tissues shaped dispersion,partial yolk was disintegrated into granule,cell membrane of embryos broke off,ice holes appeared inside embryos.Surface of 90% embryos was sunken and wrinkled,but the cuticle of 10% embryos retained slick and intact by SEM.The results implied that the original zoea stage of embryos was the appropriate stage for cryopreservation.