Lampreys, as an important participant in the ecosystem, play an irreplaceable role in the stability of nature. A variety of models were used to simulate ecosystems and food webs, and the dynamic evolution of multiple ...Lampreys, as an important participant in the ecosystem, play an irreplaceable role in the stability of nature. A variety of models were used to simulate ecosystems and food webs, and the dynamic evolution of multiple populations was solved. The temporal changes of the biomass and the health of the ecosystem affected by the population of Lampreys in other ecological niches were solved. For problem 1, Firstly, a simple natural ecosystem is simulated based on the threshold model and BP neural network model. The dynamic change of the sex ratio of lampreys population and the fluctuation of ecosystem health value were found to generate time series maps. Lampreys overprey on low-niche animals, which damages the overall stability of the ecosystem. For problem 2, We used the Lotka-Volterra model to construct ecological competition between lampreys and primary consumers and predators. Then, the Lotka-Volterra equations were solved, and a control group without gender shift function was set up, which reflected the advantages and disadvantages of the sex-regulated characteristics of lampreys in the natural environment. For problem 3, The ecosystem model established in question 1 was further deepened, and the food web was simulated by the Beverton-Holt model and the Logistic time-dependent differential equations model. The parameters of the food web model were input into the neurons of the ecosystem model, and the two models were integrated to form an overall biosphere model. The output layer of the ecosystem neural network was input into the food web Beverton-Holt and Logistic differential equations, and finally, the three-dimensional analytical solution was obtained by numerical simulation. Then Euler method is used to obtain the exact value of the solution surface. The Random forest model was used to predict the future development of lampreys and other ecological niches. For problem 4, By investigating relevant literature, we normalized the populations of lampreys and a variety of fish as well as other ecological niche anim展开更多
Spinal cord injury leads to persistent behavioral deficits because mammalian central nervous system axons fail to regenerate. A neuron's response to axon injury results from a complex interplay of neuron-intrinsic...Spinal cord injury leads to persistent behavioral deficits because mammalian central nervous system axons fail to regenerate. A neuron's response to axon injury results from a complex interplay of neuron-intrinsic and environmental factors. The contribution of axotomy to the death of neurons in spinal cord injury is controversial because very remote axotomy is unlikely to result in neuronal death, whereas death of neurons near an injury may reflect environmental factors such as ischemia and inflammation. In lampreys, axotomy due to spinal cord injury results in delayed apoptosis of spinal-projecting neurons in the brain, beyond the extent of these environmental factors. This retrograde apoptosis correlates with delayed resealing of the axon, and can be reversed by inducing rapid membrane resealing with polyethylene glycol. Studies in mammals also suggest that polyethylene glycol may be neuroprotective, although the mechanism(s) remain unclear. This review examines the early, mechanical, responses to axon injury in both mammals and lampreys, and the potential of polyethylene glycol to reduce injury-induced pathology. Identifying the mechanisms underlying a neuron's response to axotomy will potentially reveal new therapeutic targets to enhance regeneration and functional recovery in humans with spinal cord injury.展开更多
Some neurons,especially in mammalian peripheral nervous system or in lower vertebrate or in vertebrate central nervous system(CNS)regenerate after axotomy,while most mammalian CNS neurons fail to regenerate.There is a...Some neurons,especially in mammalian peripheral nervous system or in lower vertebrate or in vertebrate central nervous system(CNS)regenerate after axotomy,while most mammalian CNS neurons fail to regenerate.There is an emerging consensus that neurons have different intrinsic regenerative capabilities,which theoretically could be manipulated therapeutically to improve regeneration.Population-based comparisons between"good regenerating"and"bad regenerating"neurons in the CNS and peripheral nervous system of most vertebrates yield results that are inconclusive or difficult to interpret.At least in part,this reflects the great diversity of cells in the mammalian CNS.Using mammalian nervous system imposes several methodical limitations.First,the small sizes and large numbers of neurons in the CNS make it very difficult to distinguish regenerating neurons from non-regenerating ones.Second,the lack of identifiable neurons makes it impossible to correlate biochemical changes in a neuron with axonal damage of the same neuron,and therefore,to dissect the molecular mechanisms of regeneration on the level of single neurons.This review will survey the reported responses to axon injury and the determinants of axon regeneration,emphasizing non-mammalian model organisms,which are often under-utilized,but in which the data are especially easy to interpret.展开更多
The modification of proteins with ubiquitin is an important cellular mechanism for targeting abnormal or short-lived proteins for degradation.Ubiquitin-conjugating enzyme E2 D2 is a protein that is encoded by the UBE2...The modification of proteins with ubiquitin is an important cellular mechanism for targeting abnormal or short-lived proteins for degradation.Ubiquitin-conjugating enzyme E2 D2 is a protein that is encoded by the UBE2D2 gene.Here,we report a lamprey(La UBE2D2)gene which contained 441-bp open reading frame(ORF)encoding 147 amino acids with a typical UBC domain.Real-time PCR assay showed that the highest expression of the protein in adult lamprey was in the leukocytes,the lowest expression was in the skin,kidney and liver.The high conservation in amino acid sequence of the La UBE2D2protein with the UBE2D2s from Homo sapiens,Danio rerio,Oreochromis niloticus and Takifugu rubripes,implied that it had similar function with UBE2D2proteins from other species.展开更多
Lampreys belong to the superclass Cyclostomata and represent the most ancient group of vertebrates. Existing for over 360 million years, they are known as living fossils due to their many evolutionally conserved featu...Lampreys belong to the superclass Cyclostomata and represent the most ancient group of vertebrates. Existing for over 360 million years, they are known as living fossils due to their many evolutionally conserved features. They are not only a keystone species for studying the origin and evolution of vertebrates, but also one of the best models for researching vertebrate embryonic development and organ differentiation. From the perspective of genetic information, the lamprey genome remains primitive compared with that of other higher vertebrates, and possesses abundant functional genes. Through scientific and technological progress, scientists have conducted in-depth studies on the nervous, endocrine, and immune systems of lampreys. Such research has significance for understanding and revealing the origin and evolution of vertebrates, and could contribute to a greater understanding of human diseases and treatments. This review presents the current progress and significance of lamprey research.展开更多
It has become clear that the extant vertebrates are divided into three major groups, that is, hagfishes, lampreys, and jawed vertebrates. Morphological and molecular studies, however, have resulted in conflicting view...It has become clear that the extant vertebrates are divided into three major groups, that is, hagfishes, lampreys, and jawed vertebrates. Morphological and molecular studies, however, have resulted in conflicting views with regard to their interrelationships. To clarify the phylogenetic relationships between them, 48 orthologous protein-coding gene families were analyzed. Even as the analysis of 34 nuclear gene families supported the monophyly of cyclostomes, the analysis of 14 mitochondrial gene families suggested a closer relationship between lampreys and gnathostomes compared to hagfishes. Lampreys were sister group of gnathostomes. The results of this study supported the cyclostomes. Choice of outgroup, tree-making methods, and software may affect the phylogenetic prediction, which may have caused much debate over the subject. Development of new methods for tackling such problems is still necessary.展开更多
Abundances of important and imperiled fishes of the Snake River Basin continue to decline.We assessed the rationale for breaching the four lower Snake River Basin dams to prevent complete loss of these fishes,and to m...Abundances of important and imperiled fishes of the Snake River Basin continue to decline.We assessed the rationale for breaching the four lower Snake River Basin dams to prevent complete loss of these fishes,and to maximize their likelihood of recovery.We summarize the science surrounding Sockeye Salmon(Oncorhynchus nerka),Chinook Salmon(O.tshawytscha),steelhead(O.mykiss),Bull Trout(Salvelinus confluentus),White Sturgeon(Acipenser transmontanus),and Pacific Lamprey(Entosphenus tridentatus).From this,we drew ten conclusions:(1)development of the Columbia River System(including the Snake River Basin)has converted mainstem rivers into reservoirs,altering fish behavior and survival;(2)most populations currently record their lowest abundance;(3)the Columbia River System dams reduce productivity of diadromous fishes in the highest-quality spawning grounds that could buffer against future climate dynamics;(4)past actions have done little to reduce impacts or precipitate recovery;(5)the Columbia River System constrains survival and productivity of salmon,steelhead and Bull Trout;(6)Snake River Basin salmon and steelhead remain at high extinction risk;(7)eliminating migration impediments and improving mainstem habitats are essential for maintaining genetic diversity and improving Bull Trout persistence;(8)the lower Snake River Basin dams preclude passage of adult White Sturgeon,constraining gene flow and recruitment;(9)the lower Snake River Basin dams impede dramatically passage of adult and juvenile Pacific Lamprey,and(10)Snake River Basin Pacific Lamprey is at high risk of extirpation.Breaching the four lower Snake River Basin dams is an action likely to prevent extirpation and extinction of these fishes.Lessons from the Columbia River System can inform conservation in other impounded rivers.展开更多
文摘Lampreys, as an important participant in the ecosystem, play an irreplaceable role in the stability of nature. A variety of models were used to simulate ecosystems and food webs, and the dynamic evolution of multiple populations was solved. The temporal changes of the biomass and the health of the ecosystem affected by the population of Lampreys in other ecological niches were solved. For problem 1, Firstly, a simple natural ecosystem is simulated based on the threshold model and BP neural network model. The dynamic change of the sex ratio of lampreys population and the fluctuation of ecosystem health value were found to generate time series maps. Lampreys overprey on low-niche animals, which damages the overall stability of the ecosystem. For problem 2, We used the Lotka-Volterra model to construct ecological competition between lampreys and primary consumers and predators. Then, the Lotka-Volterra equations were solved, and a control group without gender shift function was set up, which reflected the advantages and disadvantages of the sex-regulated characteristics of lampreys in the natural environment. For problem 3, The ecosystem model established in question 1 was further deepened, and the food web was simulated by the Beverton-Holt model and the Logistic time-dependent differential equations model. The parameters of the food web model were input into the neurons of the ecosystem model, and the two models were integrated to form an overall biosphere model. The output layer of the ecosystem neural network was input into the food web Beverton-Holt and Logistic differential equations, and finally, the three-dimensional analytical solution was obtained by numerical simulation. Then Euler method is used to obtain the exact value of the solution surface. The Random forest model was used to predict the future development of lampreys and other ecological niches. For problem 4, By investigating relevant literature, we normalized the populations of lampreys and a variety of fish as well as other ecological niche anim
基金supported by grants R01-NS092876(NIH,to MES)SHC-85400(Shriners Research Foundation,to MES)SHC-85220(Shriners Research Foundation,to MES)
文摘Spinal cord injury leads to persistent behavioral deficits because mammalian central nervous system axons fail to regenerate. A neuron's response to axon injury results from a complex interplay of neuron-intrinsic and environmental factors. The contribution of axotomy to the death of neurons in spinal cord injury is controversial because very remote axotomy is unlikely to result in neuronal death, whereas death of neurons near an injury may reflect environmental factors such as ischemia and inflammation. In lampreys, axotomy due to spinal cord injury results in delayed apoptosis of spinal-projecting neurons in the brain, beyond the extent of these environmental factors. This retrograde apoptosis correlates with delayed resealing of the axon, and can be reversed by inducing rapid membrane resealing with polyethylene glycol. Studies in mammals also suggest that polyethylene glycol may be neuroprotective, although the mechanism(s) remain unclear. This review examines the early, mechanical, responses to axon injury in both mammals and lampreys, and the potential of polyethylene glycol to reduce injury-induced pathology. Identifying the mechanisms underlying a neuron's response to axotomy will potentially reveal new therapeutic targets to enhance regeneration and functional recovery in humans with spinal cord injury.
基金supported by 85310-PHI Shriners Research Foundation(to MIS)NIH R01 NS092876(to MES)
文摘Some neurons,especially in mammalian peripheral nervous system or in lower vertebrate or in vertebrate central nervous system(CNS)regenerate after axotomy,while most mammalian CNS neurons fail to regenerate.There is an emerging consensus that neurons have different intrinsic regenerative capabilities,which theoretically could be manipulated therapeutically to improve regeneration.Population-based comparisons between"good regenerating"and"bad regenerating"neurons in the CNS and peripheral nervous system of most vertebrates yield results that are inconclusive or difficult to interpret.At least in part,this reflects the great diversity of cells in the mammalian CNS.Using mammalian nervous system imposes several methodical limitations.First,the small sizes and large numbers of neurons in the CNS make it very difficult to distinguish regenerating neurons from non-regenerating ones.Second,the lack of identifiable neurons makes it impossible to correlate biochemical changes in a neuron with axonal damage of the same neuron,and therefore,to dissect the molecular mechanisms of regeneration on the level of single neurons.This review will survey the reported responses to axon injury and the determinants of axon regeneration,emphasizing non-mammalian model organisms,which are often under-utilized,but in which the data are especially easy to interpret.
文摘The modification of proteins with ubiquitin is an important cellular mechanism for targeting abnormal or short-lived proteins for degradation.Ubiquitin-conjugating enzyme E2 D2 is a protein that is encoded by the UBE2D2 gene.Here,we report a lamprey(La UBE2D2)gene which contained 441-bp open reading frame(ORF)encoding 147 amino acids with a typical UBC domain.Real-time PCR assay showed that the highest expression of the protein in adult lamprey was in the leukocytes,the lowest expression was in the skin,kidney and liver.The high conservation in amino acid sequence of the La UBE2D2protein with the UBE2D2s from Homo sapiens,Danio rerio,Oreochromis niloticus and Takifugu rubripes,implied that it had similar function with UBE2D2proteins from other species.
基金supported by the National Program on Key Basic Research Project(973 Program)(2013CB835304)National Natural Science Foundation of China(31501911)+1 种基金General Scientific Research Foundation of Liaoning Educational Committee(L2015293)Youth Scientific Research Project of Liaoning Normal University(LS2014L008)
文摘Lampreys belong to the superclass Cyclostomata and represent the most ancient group of vertebrates. Existing for over 360 million years, they are known as living fossils due to their many evolutionally conserved features. They are not only a keystone species for studying the origin and evolution of vertebrates, but also one of the best models for researching vertebrate embryonic development and organ differentiation. From the perspective of genetic information, the lamprey genome remains primitive compared with that of other higher vertebrates, and possesses abundant functional genes. Through scientific and technological progress, scientists have conducted in-depth studies on the nervous, endocrine, and immune systems of lampreys. Such research has significance for understanding and revealing the origin and evolution of vertebrates, and could contribute to a greater understanding of human diseases and treatments. This review presents the current progress and significance of lamprey research.
基金the National Natural Science Foundation of China （No. 60575005） the Natural Science Foundation of Liaoning Province （No. 20072152）+3 种基金 Key Project of Science and Technology of the Educational Ministry of China （No. 206032） the Science and Technology Project of Dalian City （No. 2006E11SF068） the National High Technology Research and Development Program of China （No. 2007AA09ZA28） the National Basic Research Program of China （No. 2007CB815802）.
文摘It has become clear that the extant vertebrates are divided into three major groups, that is, hagfishes, lampreys, and jawed vertebrates. Morphological and molecular studies, however, have resulted in conflicting views with regard to their interrelationships. To clarify the phylogenetic relationships between them, 48 orthologous protein-coding gene families were analyzed. Even as the analysis of 34 nuclear gene families supported the monophyly of cyclostomes, the analysis of 14 mitochondrial gene families suggested a closer relationship between lampreys and gnathostomes compared to hagfishes. Lampreys were sister group of gnathostomes. The results of this study supported the cyclostomes. Choice of outgroup, tree-making methods, and software may affect the phylogenetic prediction, which may have caused much debate over the subject. Development of new methods for tackling such problems is still necessary.
文摘Abundances of important and imperiled fishes of the Snake River Basin continue to decline.We assessed the rationale for breaching the four lower Snake River Basin dams to prevent complete loss of these fishes,and to maximize their likelihood of recovery.We summarize the science surrounding Sockeye Salmon(Oncorhynchus nerka),Chinook Salmon(O.tshawytscha),steelhead(O.mykiss),Bull Trout(Salvelinus confluentus),White Sturgeon(Acipenser transmontanus),and Pacific Lamprey(Entosphenus tridentatus).From this,we drew ten conclusions:(1)development of the Columbia River System(including the Snake River Basin)has converted mainstem rivers into reservoirs,altering fish behavior and survival;(2)most populations currently record their lowest abundance;(3)the Columbia River System dams reduce productivity of diadromous fishes in the highest-quality spawning grounds that could buffer against future climate dynamics;(4)past actions have done little to reduce impacts or precipitate recovery;(5)the Columbia River System constrains survival and productivity of salmon,steelhead and Bull Trout;(6)Snake River Basin salmon and steelhead remain at high extinction risk;(7)eliminating migration impediments and improving mainstem habitats are essential for maintaining genetic diversity and improving Bull Trout persistence;(8)the lower Snake River Basin dams preclude passage of adult White Sturgeon,constraining gene flow and recruitment;(9)the lower Snake River Basin dams impede dramatically passage of adult and juvenile Pacific Lamprey,and(10)Snake River Basin Pacific Lamprey is at high risk of extirpation.Breaching the four lower Snake River Basin dams is an action likely to prevent extirpation and extinction of these fishes.Lessons from the Columbia River System can inform conservation in other impounded rivers.
