Ontogenetic difference of beak elemental concentration and its possible application in migration reconstruction for Ommastrephes bartramii in the North Pacific Ocean

The migration route of oceanic squid provides critical information for us to understand their spatial and temporal variations.Mark-recapture and electronic tags tend to be problematic during processing.Cephalopod hard structures such as the beak,containing abundant ecological information with stable morphology and statolithlike sequences of growth increments,may provide information for studying spatio-temporal distribution.In this study,we developed a method,which is based on elemental concentration of beaks at different ontogenetic stages and sampling locations,to reconstruct the squid migration route.We applied this method to Ommastrephes bartramii in the North Pacific Ocean.Nine trace elements were detected in the rostrum sagittal sections(RSS)of the beak using laser ablation inductively coupled plasma mass spectrometry(LA-ICP-MS).For those elements,significant differences were found between the different ontogenetic stages for phosphorus(P),copper(Cu)and zinc(Zn).Sodium(Na),P and Zn were chosen as indicators of sea surface temperature(SST)and a regression model was estimated.The high probability of occurrence in a particular area represented the possible optimal squid location based on a Bayesian model.A reconstructed migration route in this study,combining all the locations at different ontogenetic stages,was consistent with that hypothesized in previous studies.This study demonstrates that the beak can provide useful information for identifying the migration routes of oceanic squid.

δ13C and δ15N in Humboldt squid beaks: understanding potential geographic population connectivity and movement

We quantified theδ^13C andδ^15N values in the lower beaks of Humboldt squid,Dosidicus gigas,collected from international waters off Costa Rica,Ecuador,Peru and Chile by Chinese squid jigging vessels during 2009,2010 and 2013.There was a significant difference in the isotopic values among regions with the lowest value off Ecuador and the highest off Chile,which were interpreted as a function of trophic effects as well as baseline values.However,constant trophic level of D.gigas across its geographic range showed that spatial variation in the baseline of primary production is the main driver responsible for the observed geographic isotope variability.Inter-regional difference and intra-regional convergence of isotope values indicated squid off Costa Rica,Ecuador and Chile belong to different geographically segregated populations,which were previously proved by integrated population identifying method.In contrast,the higher variations inδ^13C andδ^15N values in a given size group suggest the squid off Peru move and forage in different places.Moreover,potential population exchange could be responsible for the overlap of the isotope values between the squid off Peru and off Chile.On the whole,the spatial difference in isotopic values of Humboldt squid beaks improves our understanding of potential geographic population connectivity and movement.

Growth marks in eyestalks of Portunus trituberculatus:A development of technique and evidence of molting

The analysis of growth bands in the eyestalk has been increasingly used for estimating crustacean ageing and molting.In this study,we developed an effective method to process and observe the eyestalk microstructure of the swimming crab(Portunus trituberculatus).We found that dark pigmentation as a result of boiling has an influence on the observation of the eyestalk microstructure.Choosing an unboiled eyestalk,this study compared the cross section and longitudinal section,and concluded that the cross section is suitable for the observation of growth increments with 6.1%CV(coefficient of variation),and growth bands are suitable for the observation of the longitudinal section with 5.4%CV.The width of growth increments near the edge of the endocuticle is small,and the width of growth increments of the middle part of the endocuticle is large.Relationship of number of growth bands to molting time was fitted to a linear function with the slope not significantly different from 1,indicating that growth bands are formed associated with molting.Periodicity of growth increment formation was calculated as 3.7 d,however was not verified.Our results provide a new improved technique for identification of crustacean molting and growth.

Vampyroteuthis pseudoinfernalis sp.nov.:the second extant widespread deep sea squid species of Vampyromorpha(Cephalopoda:Coleoidea)

The vampire squid,Vampyroteuthis infernalis Chun,1903,is currently the only extant species in the family Vampyroteuthidae Chun,1903.However,specimens from the Gulf of Guinea,Africa,and California suggested the possibility of additional taxa.Here,we report the second species of Vampyroteuthis,collected from the South China Sea,China,which differs from V.infernalis by its tail shape,lower beak,photophores position,and the phylogenetic analysis of mitochondrial COI and nuclear large subunit ribosomal DNA(LSU)sequences:V.infernalis present by the lacking of the tail,photophores located approximately one-third of the points between the fins and end,and the lower beak with a broad,short wing;V.pseudoinfernalis Qiu,Liu&Huang,sp.nov.present by an acuate tail,a pair of photophores located at the midpoints between the fins and tail,and a lower beak with a broad,elongate wing.

The cellular uptake and anti-tumor activity of conjugated linoleic acid-paclitaxelloaded iRGD-modified lysolipid-containing thermosensitive liposomes

In the present study, we prepared the iRGD-modified lysolipid-containing thermosensitive liposomes(LTSL) containing conjugated linoleic acid-paclitaxel(CLA-PTX), also known as iRGD-LTSL-CLA-PTX. The in vitro cellular uptake and in vitro cytotoxicity of iRGD-LTSL-CLA-PTX were evaluated in B16-F10 melanoma cells. The in vivo anti-tumor effect of i RGD-LTSL-CLA-PTX was investigated using B16-F10 tumor-bearing C57BL/6 mice. The results of the cellular uptake experiment indicated that the increased cellular uptake of CLA-PTX in the iRGD-LTSL-CLA-PTX-treated groups was 2.05-, 3.31-or 4.83-fold compared with that in the SSL-CLA-PTX group after a 2-, 4-or 6-h incubation at 42 °C, respectively. The in vivo antitumor results showed that iRGD-LTSL-CLA-PTX/heat significantly inhibited the growth of B16-F10 tumors compared with the CLA-PTX solution(LTSL-CLA-PTX, LTSL-CLA-PTX/heat and iRGD-LTSL-CLA-PTX)(P<0.01). In conclusion, the antitumor effect of iRGD-LTSL-CLA-PTX was confirmed on B16-F10 melanoma in vitro and in vivo, which was induced by both the effect of iRGD and LTSL.

Comparative age and growth of Uroteuthis chinensis and Uroteuthis edulis from China Seas based on statolith

To determine the age and growth of Uroteuthis chinensis and U.edulis,growth increments of the lateral dome of the statolith were used in the present study.Specimens of the two species caught in the South China Sea(SCS)and East China Sea(ECS)were used to compare the age and growth differences between sexes.In the present study,we found the two species have similar lifespans of less than 200 days.We also found that there were significant differences in the relationships between mantle length and body weight for two species and for both sexes in the same species.The back-calculated hatching date for the two species was similar,i.e.October to January for specimens caught in spring,and March to June for specimens caught in summer(U.edulis)or autumn(U.chinensis).Exponential and logistic growth curves were fitted to build the age and mantle length relationship.Both growth curves showed that U.chinensis has a larger mantle length than U.edulis at the same age.The results of the growth rates also showed that U.chinensis grows faster than U.edulis.However,there are discrepancies between previous studies and the present study on the lifespan of the two species.Also,the sample size of the present study is small especially for U.edulis.Hence,future studies should be conducted to validate the daily periodicity of growth increment in the regions of statolith(except for the lateral dome which has been validated)and the sample size should be increased for age and growth studies.

Inter-individual variation in trophic history of Dosidicus gigas,as indicated by stable isotopes in eye lenses

Isotopic signatures have been extensively used to reconstruct marine organism trophic habitat over their lifetime.In this study,sequential stable isotopic values ofδ13C andδ15N in eye lenses were measured to investigate the trophic history of Dosidicus gigas during ontogeny.A total of 281 segments from 33 lenses were examined withδ13C ranging from−20.17‰to−16.11‰andδ15N ranging from 5.15‰to 18.74‰.Sequential increasing but variableδ13C andδ15N values in eye lenses indicated that the prey used in the model had a wide range of values,it became able to consume prey from higher trophic levels,perhaps to maximize feeding success.High inter-individual differences in the range and considerable inter-individual variation in the trend of the isotopic values of the sequential segments from the nuclear to the periphery were considered to be the result of the effects of food and the best feeding strategy.These inter-individual isotopic differences in the life history of D.gigas confirmed the high degree of plasticity of feeding for this squid and its high potential to adapt to environmental change.Inter-individual differences ofδ15N values in the growth of D.gigas were more likely to be caused by differences in the baseline values of isotopes.According to the population discrimination model ofδ15N value changes during ontogeny,the D.gigas off Peru fit the model of“generalist population-generalist individuals”.

Synthesis of poly(amidoamine)-poly(ethyleneglycol)-poly(amidoamine) and preparation of its hydrogel solution containing doxorubicin

Many pH-and temperature-responsive polymers have been designed for preparing hydrogel.In the present study,in order to decrease the pH sensitivity of reported poly(amidoamine)-poly(ethyleneglycol)-poly(amidoamine)(PAA1580-PEG4600-PAA1580),we designed and synthesized poly(amidoamine)-poly(ethyleneglycol)-poly(amidoamine)(PAA-PEG-PAA)with shorter length of PAA chain by decreasing reaction temperature for preparing PAA-PEG-PAA hydrogel solution containing doxorubicin(DOX).The PAA-PEG-PAA was synthesized via the Michael-addition polymerization.The characteristic of PAA-PEG-PAA was evaluated.The PAA-PEG-PAA hydrogel solution was prepared and investigated.DOX-loaded PAA-PEG-PAA hydrogel solution was prepared,and its in vitro DOX release and in vitro anti-tumor activity were evaluated.Our results indicated that the viscosity of PAA-PEG-PAA hydrogel solution was concentration-and temperature-dependent.The sol-gel transition temperature of PAA-PEG-PAA hydrogel solution(12%,w/w)ranged from 35 to 29℃,and its pH ranged from 6.0 to 7.4.The released DOX from DOX-loaded PAA-PEG-PAA hydrogel showed sustained release characteristics.The in vitro anti-tumor activity of DOX-loaded PAA-PEG-PAA hydrogel was confirmed in B16 F10 cell line.Considering the acidic tumor microenvironment,this DOX-loaded PAA-PEG-PAA hydrogel solution would be easy in situ administration for intra-tumor injection or para-tumor injection forming hydrogel at body temperature.We suggested that this DOX-loaded PAA-PEG-PAAhydrogel solution,if containing photothermal conversion agents,would have a potential further use for photothermal therapy.