Natural nano-hydroxyapatite(HA)was extracted from Pacific cod(Gadus macrocephalus)bone with a thermostable col-lagenolytic protease in the present study.Conditions for the enzymatic reaction were optimized to be 60℃a...Natural nano-hydroxyapatite(HA)was extracted from Pacific cod(Gadus macrocephalus)bone with a thermostable col-lagenolytic protease in the present study.Conditions for the enzymatic reaction were optimized to be 60℃and pH 7.0,and a desir-able extraction efficiency was achieved by using the crude collagenolytic protease.Dynamic light scattering,transmission electron microscopy and energy-dispersive X-ray analysis revealed that nano-HA are anionic spherical(about 110nm)particles mainly com-prised of calcium and phosphorus at an approximate ratio of 5:3.As evaluated with the mouse ex vivo intestinal segments,the extracted nano-HA displayed comparable level of intestinal bioavailability to the positive control CaCl_(2).By treating with inhibitors(NaN3,ami-loride)and low temperature(4℃),clathrin-mediated endocytosis was assumed to involve the intestinal absorption of nano-HA.Over-all,the application of thermostable collagenolytic protease is proved to be a promising alternative method for nano-HA extraction from natural resource with improved ecological and biological value.展开更多
Growth of black porgy. Sparus macrocephalus was studied experimentally at four ration lerels from starvation to sltiation and tour temperatures ranging from 14.8 to 26.8℃ .At maximum rations. the specific growth rate...Growth of black porgy. Sparus macrocephalus was studied experimentally at four ration lerels from starvation to sltiation and tour temperatures ranging from 14.8 to 26.8℃ .At maximum rations. the specific growth rate (SGR) increased with temperature and was a negative linear function of body weight. The relationship betaren SGR and ration levels was a decelerating curve. Stepwise mpgression was used to derelop the predictive models for the specific growth rates. Maintenance rations and optimum ratlons both increased with increased temperature. The relationship between maintenance. optimum rations and body welght wds influenced by temperuture. Conversion efficiencies increased with ration from zero at maintenance ration to a peak at the optimum ration, then declined with further inceased ration.展开更多
The sea area surrounding Baishishan Island has abundant fishery resources because of its plentiful food and rocky reefs that provide refuge from predators.However,overfishing has occurred in many areas and some specie...The sea area surrounding Baishishan Island has abundant fishery resources because of its plentiful food and rocky reefs that provide refuge from predators.However,overfishing has occurred in many areas and some species’local populations need to be replenished through stocking programs.This case study,using Sparus microcephalus as the test species,designed and analyzed detailed stocking strategies to improve the survival ratio and control the active range of the released fishes.Controlled variables included release location,release time,and tidal level.Two stocking strategies were designed,executed,and evaluated for comparison.A traditional stocking method was applied to the high flow area of Baishishan Island in Xiangshan Bay,East China Sea.The released fry were transported by boat and released to the sea using buckets.Released fish were traced using plastic tags.The average distance of the 19 recaptured fry from the release point was 7.6 km with 52.9%mortality rate.The distance at recapture and mortality rate among recaptured individuals showed that the traditional releasing method was not successful.An in situ stocking method was used in a low tide area and natural process was imitated to decrease the stress response and promote physiological adaptation.The purpose of this method was to prolong the release process applying temporary net cages at the release location,which resulted in a regional distribution of the released fish and possibly improving the food availability.A new Sr+tagging technique was adopted to evaluate the release effect and quantify comparative release data.Only 1 fish among the 354 caught was found farther than 1 km from the release point in the following 6 months.The results validated the promotion of the new stocking technique.展开更多
Rodents with prevailing subterranean activity usually play an important role in the ecosystems of which they are a part due to the combined effect of herbivory and soil perturbation.This is the case for the giant root...Rodents with prevailing subterranean activity usually play an important role in the ecosystems of which they are a part due to the combined effect of herbivory and soil perturbation.This is the case for the giant root-rat Tachyoryctes macrocephalus endemic to the Afroalpine ecosystem of the Bale Mountains,Ethiopia.We studied the impact of root-rats on various ecosystem features within a 3.5-ha study locality dominated by Alchemilla pasture,which represents an optimal habitat for this species,in 2 periods of a year.The root-rats altered plant species composition,reducing the dominant forb,Alchemilla abyssinica,while enhancing Salvia merjame and a few other species,and reduced vegetation cover,but not the fresh plant biomass.Where burrows were abandoned by root-rats,other rodents took them over and A.abyssinica increased again.Root-rat burrowing created small-scale heterogeneity in soil compactness due to the backfilling of some unused burrow segments.Less compacted soil tended to be rich in nutrients,including carbon,nitrogen and phosphorus,which likely affected the plant growth on sites where the vegetation has been reduced as a result of root-rat foraging and burrowing.展开更多
The complex life histories of demersal fishes are artificially separated into multiple stages along with changes in morphology and habitat.It is worth exploring whether the phenotypes expressed earlier and later durin...The complex life histories of demersal fishes are artificially separated into multiple stages along with changes in morphology and habitat.It is worth exploring whether the phenotypes expressed earlier and later during the life cycle are related or decoupled.The life stages of first year Pacific cod(Gadus macrocephalus)were tracked over different hatch years and regions to test whether the early life history had a long-lasting effect on subsequent growth.We further explored the contribution of growth in the early and subsequent life history stages to body size at the end of each stage.In addition to the accessory growth centre and the first annual ring,the other two checks on the otolith possibly related to settlement and entering deeper waters were identified in 75 Pacific cod individuals.The direct and indirect relationships among the life history stages was interpreted based on path analysis.The results showed that growth prior to the formation of the accessory growth centre had a significant effect on the absolute growth of the fish before and after settlement and migration to deep water.However,there was no or moderate evidence that early growth affected the body size at each stage,which was mainly regulated by growth during the stage.This study supports the lasting effect of early growth and clarifies that it affects size mainly by indirectly regulating staged growth.Quantifying the phenotype relationships and identifying the internal mechanisms form the basis for assessing population dynamics and understanding the processes behind the changes.展开更多
基金supported by the Natural Science Foundation of Shandong Province(No.ZR202102270334)the National Key Research and Development Program of China(No.2020YFD0901004).
文摘Natural nano-hydroxyapatite(HA)was extracted from Pacific cod(Gadus macrocephalus)bone with a thermostable col-lagenolytic protease in the present study.Conditions for the enzymatic reaction were optimized to be 60℃and pH 7.0,and a desir-able extraction efficiency was achieved by using the crude collagenolytic protease.Dynamic light scattering,transmission electron microscopy and energy-dispersive X-ray analysis revealed that nano-HA are anionic spherical(about 110nm)particles mainly com-prised of calcium and phosphorus at an approximate ratio of 5:3.As evaluated with the mouse ex vivo intestinal segments,the extracted nano-HA displayed comparable level of intestinal bioavailability to the positive control CaCl_(2).By treating with inhibitors(NaN3,ami-loride)and low temperature(4℃),clathrin-mediated endocytosis was assumed to involve the intestinal absorption of nano-HA.Over-all,the application of thermostable collagenolytic protease is proved to be a promising alternative method for nano-HA extraction from natural resource with improved ecological and biological value.
文摘Growth of black porgy. Sparus macrocephalus was studied experimentally at four ration lerels from starvation to sltiation and tour temperatures ranging from 14.8 to 26.8℃ .At maximum rations. the specific growth rate (SGR) increased with temperature and was a negative linear function of body weight. The relationship betaren SGR and ration levels was a decelerating curve. Stepwise mpgression was used to derelop the predictive models for the specific growth rates. Maintenance rations and optimum ratlons both increased with increased temperature. The relationship between maintenance. optimum rations and body welght wds influenced by temperuture. Conversion efficiencies increased with ration from zero at maintenance ration to a peak at the optimum ration, then declined with further inceased ration.
基金The study was financially supported by the National Natural Science Foundation of China(No.51309150)Special Fund for Agro-scientific Research in the Public Interest(No.201303047).
文摘The sea area surrounding Baishishan Island has abundant fishery resources because of its plentiful food and rocky reefs that provide refuge from predators.However,overfishing has occurred in many areas and some species’local populations need to be replenished through stocking programs.This case study,using Sparus microcephalus as the test species,designed and analyzed detailed stocking strategies to improve the survival ratio and control the active range of the released fishes.Controlled variables included release location,release time,and tidal level.Two stocking strategies were designed,executed,and evaluated for comparison.A traditional stocking method was applied to the high flow area of Baishishan Island in Xiangshan Bay,East China Sea.The released fry were transported by boat and released to the sea using buckets.Released fish were traced using plastic tags.The average distance of the 19 recaptured fry from the release point was 7.6 km with 52.9%mortality rate.The distance at recapture and mortality rate among recaptured individuals showed that the traditional releasing method was not successful.An in situ stocking method was used in a low tide area and natural process was imitated to decrease the stress response and promote physiological adaptation.The purpose of this method was to prolong the release process applying temporary net cages at the release location,which resulted in a regional distribution of the released fish and possibly improving the food availability.A new Sr+tagging technique was adopted to evaluate the release effect and quantify comparative release data.Only 1 fish among the 354 caught was found farther than 1 km from the release point in the following 6 months.The results validated the promotion of the new stocking technique.
基金funded by GAČR(P506/11/1512),ERC(669609)and GAJU(156/2013/P,151/2016/P).
文摘Rodents with prevailing subterranean activity usually play an important role in the ecosystems of which they are a part due to the combined effect of herbivory and soil perturbation.This is the case for the giant root-rat Tachyoryctes macrocephalus endemic to the Afroalpine ecosystem of the Bale Mountains,Ethiopia.We studied the impact of root-rats on various ecosystem features within a 3.5-ha study locality dominated by Alchemilla pasture,which represents an optimal habitat for this species,in 2 periods of a year.The root-rats altered plant species composition,reducing the dominant forb,Alchemilla abyssinica,while enhancing Salvia merjame and a few other species,and reduced vegetation cover,but not the fresh plant biomass.Where burrows were abandoned by root-rats,other rodents took them over and A.abyssinica increased again.Root-rat burrowing created small-scale heterogeneity in soil compactness due to the backfilling of some unused burrow segments.Less compacted soil tended to be rich in nutrients,including carbon,nitrogen and phosphorus,which likely affected the plant growth on sites where the vegetation has been reduced as a result of root-rat foraging and burrowing.
基金This work was financially supported by China Scholarship Council(202006330094).
文摘The complex life histories of demersal fishes are artificially separated into multiple stages along with changes in morphology and habitat.It is worth exploring whether the phenotypes expressed earlier and later during the life cycle are related or decoupled.The life stages of first year Pacific cod(Gadus macrocephalus)were tracked over different hatch years and regions to test whether the early life history had a long-lasting effect on subsequent growth.We further explored the contribution of growth in the early and subsequent life history stages to body size at the end of each stage.In addition to the accessory growth centre and the first annual ring,the other two checks on the otolith possibly related to settlement and entering deeper waters were identified in 75 Pacific cod individuals.The direct and indirect relationships among the life history stages was interpreted based on path analysis.The results showed that growth prior to the formation of the accessory growth centre had a significant effect on the absolute growth of the fish before and after settlement and migration to deep water.However,there was no or moderate evidence that early growth affected the body size at each stage,which was mainly regulated by growth during the stage.This study supports the lasting effect of early growth and clarifies that it affects size mainly by indirectly regulating staged growth.Quantifying the phenotype relationships and identifying the internal mechanisms form the basis for assessing population dynamics and understanding the processes behind the changes.
