To investigate the application effects of anisodamine in the immersion vaccination of Larimichthys crocea,the inactivated Pseudomonas plecoglossicida vaccine with anisodamine adjuvant was used for the immersion vaccination of large yellow croaker.The results showed that serum antibody levels significantly increased in both the adjuvant-free vaccine group(FKC group)and the anisodamine-supplemented vaccine group(FKCA group)during weeks 1～4 post-immunization.Notably,the FKCA group exhibited significantly elevated serum antibody levels compared with the FKC group at weeks 2～3.The results of RT-PCR indicated that immune-related genes(IgM,IL-1β,MHC-Ⅰα,MHC-Ⅱβ,CD4,and CD8)showed upregulated expression in head kidney and spleen tissues from day 4 post-immunization.Specifically,peak expression levels of IgM,IL-1β,MHC-Ⅰα,and CD8 in the head kidney were significantly higher in the FKCA group than in the FKC group.Enzyme activity assays showed that the activities of AKP and ACP in epidermal mucus reached their peaks on day 7 after immunization,while the activities of AKP and ACP in the serum reached their peaks on days 4 and 14 respectively.The AKP activity of FKCA group was significantly higher than that of FKC group.Histological examination revealed that both vaccinated groups exhibited dermal thickening and increased mucus cell density in skin tissues on day 4 post-immunization,with the FKCA group additionally demonstrating significant widening of primary gill filaments and more pronounced physiological alterations.At 28 days post-immunization,the FKCA group reached a relative protection rate of 61％post challenge,which was significantly higher than that of the FKC group(14％).Growth index analysis revealed that there were no significant differences in the average weight gain rate or specific growth rate between the vaccine group and the control group during the immunization period.As above,the research indicates that anisodamine,as an immersion vaccine adjuvant,can significantly increase the relative protection rate of the inactivated P.plecoglossicida vaccine for L.crocea,improve the serum antibody level and the relative expression level of immune genes in the head kidney,enhance the activities of AKP and ACP,and strengthen the physiological expansion responses of the skin and gill filaments to immersion immunization,without compromising growth performance.These findings highlight anisodamine as a promising adjuvant candidate for immersion vaccination in L.crocea.
A total of 156 sedimentary diatom specimens from D3-5 gravity cored sample(316 cm long)in the Powell Basin(62.2322°S,50.3449°W;water depth 3 397 m)in Antarctic during the China's 28th Antarctic Scientific Expedition from 2011 to 2012 were analyzed,from which 54 species and variants of diatoms were identified and they were dominated by marine and cold-water species.The following stages of the changes of the Powell Basin marine environment since the Late Pleistocene were established based on diatom analysis.During the 58.6～72.5 ka BP period,diatoms were dominated by cold-water and sea-ice species,and coastal species appeared.It was inferred that due to the growth of the Antarctic ice sheet,the Powell Basin was under the control of polar cold-water mass,with distinct cold-warm alternations in climate.Besides,the sea level was low and the water depth was shallow.During the 40.7～58.6 ka BP period,there was an obvious climate cold-warm change.The marine environment was greatly affected by climate change and becomes unstable.It was inferred that due to the melting of sea ice,the strengthening of thermohaline circulation,and the frequent occurrence of ice-rafted debris events,the species and abundance of diatoms decreased sharply.In the 26.2～40.7 ka BP period,the diatom species increased significantly,and the sea-ice appeared and cold-water species increased.It was speculated that in the early stage of ice-sheet growth of the Last Glacial Period,the influence range of the mid-latitude warm water mass in the Antarctic Sea area expanded southwards,and the cold and warm water masses were strongly mixed to drive the thermohaline circulation.From 26.2 ka BP to the present,the abundance of diatoms increased with the occurrence of diatom species Fragilariopsis oceanica indicating mixed with polar cold and warm water,suggesting that the mix of surface and bottom water in the study area was enhanced.Besides,the sea ice coverage area continued to expand,the Weddell Circulation was strengthened,while the influence of mid-latitude warm water was weakened.Overall,the Powell Basin underwent a transition from the cold period(development of the Antarctic Ice Sheet)to the warm period,and then to the cold period(the Last Glacial Period)since the Late Pleistocene,and there was a long period of ice-rafted debris events in the MIS 3 stage.
Mesoscale oceanic eddies are critically important phenomena in the ocean.The sea surface temperature anomalies they induce can alter the heat fluxes at the air-sea interface,subsequently affecting the marine atmospheric boundary layer and the free atmosphere,thereby exerting influences on both local and global climates.Therefore,based on observational and reanalysis data,spatiotemporal filtering and dynamical compositing methods were employed to examine the modulation of air-sea heat exchange by mesoscale eddies in the tropical Northwest Pacific from 1993 to 2019.Results indicate that anticyclonic(cyclonic)eddies are associated with warm(cold)sea surface temperature(SST)anomalies,which lead to an increase(decrease)in the air-sea temperature gradient,thereby enhancing(reducing)evaporation and subsequently increasing(decreasing)the heat flux from the ocean to the atmosphere.These anomalies in air-sea variables decrease gradually outward from the eddy center,following an exponential Gaussian-like distribution.SST anomalies induced by mesoscale eddies are identified as the primary driver of variations in the air-sea temperature gradient,evaporation rate,and heat flux.For anticyclonic eddies,the linear regression coefficients between SST anomalies and anomalies in the air-sea temperature gradient,evaporation rate,sensible heat flux,and latent heat flux are 0.91,48.2 cm/(a·℃),11.6 W/(m2·℃),38.3 W/(m2·℃),respectively.For cyclonic eddies,the corresponding coefficients are 0.77,37.5 cm/(a·℃),10.0 W/(m2·℃),36.8 W/(m2·℃).The analysis suggests that anticyclonic eddies exert a more pronounced influence on the atmosphere compared to cyclonic eddies,a finding that contrasts with studies in the Kuroshio Extension and the South China Sea,where cyclonic eddies have a more significant forcing effect.This research elucidated the forcing characteristics of mesoscale eddies on air-sea heat flux in the tropical northwest Pacific,identified the critical factors influencing air-sea heat flux,and underscores the regional differences in these processes,and provided an important foundation for further investigation into mesoscale eddy-air-sea coupling mechanisms.
Neo-male fish are induced from genetic females and are indispensable in the large-scale cultivation of all-female seedlings.However,studies on their sperm vitality are scarce in China and the world.To investigate the changes in sperm motility of neo-male yellow drum(Nibea albiflora)during the breeding season and the effects of environmental factors on its motility,we utilized a computer-assisted sperm analysis(CASA)system to assess the sperm concentration,motility,life span,and velocity.Additionally,various temperature and pH gradients were set to determine their effects on sperm motility in the neo-males.Results indicate that the sperm concentration of neo-males ranged(2.24～2.60)× 1010 cells/mL.Throughout the breeding season,the sperm concentration of neo-males exhibited a gradual decline,and during the middle and late stages of breeding,the sperm concentration was significantly higher than that of males.The CASA analysis revealed that sperm motility in neo-males increased at first and then decreased in the breeding season,and the motility rates in neo-males surpassed those of males,although their life span and velocity were lower than those of males.Furthermore,the effects of water temperature and pH on sperm motility during the mid-breeding season were analyzed,using seawater to activate the sperm of neo-males.It was observed that when seawater temperatures ranged from 16 to 24 ℃,the sperm motility rates and life span increased at beginning,and then declined.At 22 ℃,neo-males exhibited the highest motility and life span,recorded at 83.58％and 270.67 s,respectively;however,there were no significant variations in sperm velocity in different activation temperatures.When seawater pH ranged from 6.9 to 8.9,sperm motility of neo-males also displayed an initial increase followed by a decrease.At pH 7.9,neo-males had highest motility and life span,measured at 83.62％and 263.64 s,and exhibited peak speed at this pH level.We demonstrated that the neo-males had higher sperm concentration and motility but a shorter life span compared to the males.Furthermore,both neo-male and male fish sperms exhibited similar trends in motility in response to varying temperature and pH conditions.The present study provides valuable insights for the large-scale production of all-female N.albiflora.
Hyriopsis cumingii and Cristaria plicata are the primary freshwater pearl mussels in China accounting for over 90％of the global pearl production.Developing sperm cryopreservation techniques for these is essential for germplasm conservation and genetic breeding.This study optimized cryopreservation techniques for both species by comparing key parameters such as cryoprotectants,equilibration times,packaging,extenders,and cooling procedures,using sperm motility and survival rates as evaluation indicators.Optimal conditions included 5％and 8％DMSO for H.cumingii and C.plicata sperm,respectively,supplemented with 0.05 mol/L trehalose.The 0.5 mL straw was identified as the optimal container for both species,outperforming 0.25 mL straws and 0.5 mL cryovials.For H.cumingii,the ideal equilibration time was 50 minutes with 5％DMSO,whereas C.plicata showed the best performance with 8％DMSO and an equilibration time of 10 to 30 minutes.Solution D(10-fold dilution of HBSS)outperformed physiological saline and Ringer's solution as a sperm extender,with filtered pond water showing comparable results for C.plicata.Comparison of six cooling protocols identified the optimal cryopreservation procedure for H.cumingii sperm as follows:equilibration at 4 ℃ for 30 minutes,cooling at-7 ℃/min to-30 ℃,holding for 2 minutes,followed by cooling at-12 ℃/min to-80 ℃,holding for another 2 minutes,and finally plunging into liquid nitrogen.For C.plicata sperm,the best protocol involved equilibration at 4 ℃ for 30 minutes,cooling at-7 ℃/min to-80 ℃,holding for 2 minutes,and plunging into liquid nitrogen.Both species achieved the highest motility and survival rates when thawed in a 40 ℃ water bath for 8 seconds.Post-thaw motility and survival rates were 28.57％±2.02％and 71.64％±3.04％for H.cumingii,and 33.38％±3.80％and 64.04％±2.40％for C.plicata,respectively.Artificial fertilization experiments using cryopreserved H.cumingii sperm resulted in a fertilization rate of 43.93％±3.40％.These findings represent a significant advancement in sperm cryopreservation techniques,supporting hybrid breeding efforts and promoting the application of modern biotechnologies.
